Organ Donors: Recipe for long-lasting livers

Provided by ScienceDaily

Date: April 22, 2015

Source: RIKEN

Summary: A new technique that extends the time that donor organs last has been developed by researchers. The technique can also resuscitate organs obtained after cardiac arrest, the researchers say.

(Left) A natural liver. (Middle) A liver preserved using the new perfusion system at 22 degrees Celsius. (Right) A liver preserved using the standard static method at 4 degrees Celsius. Note how much similar in appearance the liver preserved using the new method is to a natural liver. Transplants with these livers proved much more effective than those using livers in the standard method. Credit: RIKEN

People waiting for organ transplants may soon have higher hopes of getting the help that they need in time. Researchers at the RIKEN Center for Developmental Biology have developed a new technique that extends the time that donor organs last and can also resuscitate organs obtained after cardiac arrest. The work published in Scientific Reports details a procedure that cools organs down to 22 °C (71.6 °F) and slows down organ function while still supplying oxygen, resulting in more successful transplants than the current standard methods. Team leader Takashi Tsuji notes that this system should quickly increase the pool of available donor organs and could even be used to grow whole 3D organs in the future.

Typically, donor organs are kept at a static temperature of 4 °C in preservation solution and have preservation times of only about 6 hours for hearts and lungs, 12 hours for livers, and 20 hours for kidneys. Lengthening these times is a high-priority goal in transplant research, and the team at RIKEN was able to do so using a 3D organ-perfusion system that supplies oxygen to the donor organ and keeps it at an ideal temperature.

Using a rat model for liver transplant, they isolated livers, placed them in culture, and hooked them up to a perfusion system that can pump essential fluids through the organs--including red blood cells, which carry much-needed oxygen. They assessed liver function at several different temperatures by measuring concentrations of certain protein markers--alanine aminotransferase, which rises in dysfunctional livers, and albumin, which is higher in healthy livers. Analysis of these markers and bile production--another sign of a healthy liver--showed that livers remained healthy the longest--up to 2 days--when preserved at 22 °C with red blood cells added to the perfusion culture. 3D-image analysis showed that when red blood cells were used, fewer liver cells died, and the complex structure of the livers remained intact.

After determining that liver cells cooled to 22 °C--but not lower--will begin to multiply again and exhibit healthy metabolism when warmed, the researchers compared the effectiveness of transplanting livers preserved for 24 hours by their new method with those preserved for 24 hours at the standard static 4 °C. Seven days after the transplant, they cut out most of the recipient's natural liver, and through this manipulation, could be sure that they were only analyzing the function of the transplanted liver. While only 20% of rats that received statically preserved livers survived after this partial hepatectomy, 100% survived after receiving livers preserved using the new hypothermic perfusion system that included red blood cells. Careful analysis showed that seven days after the partial hepatectomy, the new livers, which had been smaller than normal when transplanted, had grown to acceptable weights, and markers of liver function had returned to normal levels.

The team also tested their system on livers similar to those donated after a person has died from cardiac arrest, which in practice often go unused because they are frequently severely damaged. When red blood cells were added, these livers showed many signs of normal function after transplant, and survival rate was 100% even after partial liver removal seven days after transplant. In stark contrast, when these types of livers were transplanted using static 4 °C preservation or the new perfusion system without red blood cells, none of the rats survived after the partial hepatectomy.

While there is still a ways to go until this method will be available for humans, Tsuji is optimistic. "Optimizing the scale of the system for humans while still making it portable," he says, "will likely take about 3 years. Once that is accomplished, we should be able to begin the first human trials within a year or two."

Story Source:

The above story is based on materials provided by RIKEN. Note: Materials may be edited for content and length.

Journal Reference:

1. Jun Ishikawa, Masamitsu Oshima, Fumitaka Iwasaki, Ryoji Suzuki, Joonhong Park, Kazuhisa Nakao, Yuki Matsuzawa-Adachi, Taro Mizutsuki, Ayaka Kobayashi, Yuta Abe, Eiji Kobayashi, Katsunari Tezuka, Takashi Tsuji. Hypothermic temperature effects on organ survival and restoration. Scientific Reports, 2015; 5: 9563 DOI: 10.1038/srep09563

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Shape-shifting molecule tricks viruses into mutating themselves to death

Provided by the University of Chicago

This photograph shows part of the two-dimensional infrared spectroscopy instrument operating in the laboratory of Prof. Andrei Tokmakoff. The normally invisible infrared laser beam appears red in this image with the aid of dry ice. Photo by Robert Kozloff

By Steve Koppes

April 14, 2015

A newly developed spectroscopy method is helping to clarify the poorly understood molecular process by which an anti-HIV drug induces lethal mutations in the virus’ genetic material. The findings from the University of Chicago and the Massachusetts Institute of Technology could bolster efforts to develop the next generation of anti-viral treatments.

Viruses can mutate rapidly in order to adapt to environmental pressure. This feature also helps them become resistant to anti-viral drugs. But scientists have developed therapeutic anti-viral agents for HIV, hepatitis C and influenza using a strategy called lethal mutagenesis.

This strategy seeks to extinguish viruses by forcing their already high mutation rates above an intolerable threshold. If viruses experience too many mutations, they can’t properly manage their genetic material.

“They can’t replicate and so are quickly eliminated,” said Andrei Tokmakoff, the Henry G. Gale Distinguished Service Professor in Chemistry at UChicago. “In order to make this work, you need a stealth mutagen. You need something sneaky, something that the virus isn’t going to recognize as a problem.”

Tokmakoff and his associates at UChicago and MIT reported new details of the stealthy workings of the anti-HIV agent KP1212 in March in the Proceedings of the National Academy of Sciences. Supporting data were collected with two-dimensional infrared spectroscopy, an advanced laser technique that combines ultrafast time resolution with high sensitivity to chemical structure.

Critical tools

“Two-dimensional infrared spectroscopy will be critical on the path ahead. It lets us look at the structures that exist in aqueous solution, which is the natural milieu of cells,” said study co-author John Essigmann, MIT’s William and Betsy Leitch Professor of Chemistry, Toxicology and Biological Engineering. Essigmann is co-founder of a pharmaceutical company that is developing mutagenic inhibitors of HIV.

“We also have done nuclear magnetic resonance, which is very informative, but those studies were done in organic solvents that probably do not as accurately provide a view of what happens in cells as did the infrared studies done by the Tokmakoff group,” Essigmann said.

Scientists design lethally mutagenic molecules such as KP1212 to resemble natural DNA bases, the adenine-thymine, cytosine-guanine base pairs. “These analogs can bind to the wrong base partners and therefore lead to genetic mutations,” said the study’s lead author, Sam Peng, who was a visiting graduate research assistant at UChicago.

KP1212 is a cytosine variation, which normally would pair with guanine during replication. But biochemical experiments and clinical trials have shown that KP1212 induces mutations by pairing with adenine. A leading proposal suggested that KP1212 derived its mutagenicity by shape shifting—converting into a different molecular structure by repositioning its hydrogen atoms on nitrogen and oxygen atoms.

Scientists call this shape-shifted structure a tautomer. James Watson, SB’47, and Francis Crick proposed this tautomer hypothesis in 1953 when they announced the discovery of DNA’s double-helical structure. “The shuffled hydrogen positions in rare tautomers alter the hydrogen bonding patterns, resulting in incorrect base paring,” said Peng, who completed his doctorate at MIT in 2014 and will become a postdoctoral scientist at Stanford University later this year.

Rapid measurement

Most experimental tools would have difficulty distinguishing between the normal and shape-shifted structures because they interconvert very rapidly. With two-dimensional infrared spectroscopy, the UChicago team was able to distinguish between the two structures. The team also was able to measure how rapidly the shape shifting occurs under physiological conditions: in 20 billionths of a second.

The research team expected to find only two dominant tautomers, but their experiments showed that many more exist. In addition to taking on different forms as a neutral molecule, KP1212 also could accept an extra proton, giving it a positive charge at physiological levels of acidity—pH of approximately five and a half to seven—that made possible even more rearrangements and tautomer structures. “The number of possibilities exploded,” Tokmakoff said.

The experiments also showed that both the protonated and non-protonated forms facilitated the viral mutation rate. Even in the absence of the protonated form, the virus still mutated, just at a lower rate.

“We found that under physiological pHs, KP1212 is significantly protonated and this protonated form induces even higher mutation rates, reaching approximately 50 percent,” Peng said.

The finding that the molecule could become protonated both surprised and delighted Essigmann. The work taught his team how to create even more potent shape shifters—by decorating the KP1212 scaffold with groups of atoms and molecules that further raises their ability to capture protons.

“KP1212 is about 20 percent of the way toward being an ideal therapeutic mutagen. The hints given to us by the spectroscopy guide us toward even better mutagenic molecules,” Essigmann said.

Although Essigmann and Tokmakoff have known each other for years, they pursued seemingly far-removed research specialties until now. Tokmakoff’s biological research involves proteins, not DNA. But together their research teams were able to fruitfully undertake one of the first two-dimensional infrared spectroscopic studies of the therapeutic mechanism of an anti-viral drug.

“This is how basic research works,” Tokmakoff said. “This is how so often you get transitions from basic research to real applications. They can’t be predicted.”

---

Citation: “Two-dimensional IR spectroscopy of the anti-HIV agent KP1212 reveals protonated and neutral tautomers that influence pH-dependent mutagenicity,” by Chunte Sam Peng, Bogdan I. Fedeles, Vipender Singh, Deyu Li, Tiffany Amariuta, John M. Essigmann and Andrei Tokmakoff, Proceedings of the National Academy of Sciences, March 17, 2015, vol. 112, no. 11, pp. 3229-3234. Published online before print March 2, 2015, doi: 10.1073/pnas.1415974112.

Funding: National Science Foundation and National Institutes of Health.

Source

Repurposing of the antihistamine chlorcyclizine and related compounds for treatment of hepatitis C virus infection

Sci Transl Med 8 April 2015:
Vol. 7, Issue 282, p. 282ra49
Sci. Transl. Med. DOI: 10.1126/scitranslmed.3010286

Research Article

DRUG DISCOVERY

Shanshan He¹, Billy Lin¹, Virginia Chu¹, Zongyi Hu¹, Xin Hu², Jingbo Xiao², Amy Q. Wang², Cameron J. Schweitzer¹, Qisheng Li¹, Michio Imamura³, Nobuhiko Hiraga³, Noel Southall², Marc Ferrer², Wei Zheng², Kazuaki Chayama³, Juan J. Marugan² and T. Jake Liang¹,*

+ Author Affiliations

1. ¹Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
2. ²National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA.
3. ³Department of Medicine and Molecular Sciences, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 730-0053, Japan.

1. *Corresponding author. E-mail: jliang@nih.gov

Abstract

Hepatitis C virus (HCV) infection affects an estimated 185 million people worldwide, with chronic infection often leading to liver cirrhosis and hepatocellular carcinoma. Although HCV is curable, there is an unmet need for the development of effective and affordable treatment options. Through a cell-based high-throughput screen, we identified chlorcyclizine HCl (CCZ), an over-the-counter drug for allergy symptoms, as a potent inhibitor of HCV infection. CCZ inhibited HCV infection in human hepatoma cells and primary human hepatocytes. The mode of action of CCZ is mediated by inhibiting an early stage of HCV infection, probably targeting viral entry into host cells. The in vitro antiviral effect of CCZ was synergistic with other anti-HCV drugs, including ribavirin, interferon-α, telaprevir, boceprevir, sofosbuvir, daclatasvir, and cyclosporin A, without significant cytotoxicity, suggesting its potential in combination therapy of hepatitis C. In the mouse pharmacokinetic model, CCZ showed preferential liver distribution. In chimeric mice engrafted with primary human hepatocytes, CCZ significantly inhibited infection of HCV genotypes 1b and 2a, without evidence of emergence of drug resistance, during 4 and 6 weeks of treatment, respectively. With its established clinical safety profile as an allergy medication, affordability, and a simple chemical structure for optimization, CCZ represents a promising candidate for drug repurposing and further development as an effective and accessible agent for treatment of HCV infection.

• Copyright © 2015, American Association for the Advancement of Science

Citation: S. He, B. Lin, V. Chu, Z. Hu, X. Hu, J. Xiao, A. Q. Wang, C. J. Schweitzer, Q. Li, M. Imamura, N. Hiraga, N. Southall, M. Ferrer, W. Zheng, K. Chayama, J. J. Marugan, T. J. Liang, Repurposing of the antihistamine chlorcyclizine and related compounds for treatment of hepatitis C virus infection. Sci. Transl. Med. 7, 282ra49 (2015).

Source

NCKU research team discovers new treatment for liver diseases

Taipei, Taiwan, June 3, 2014

A Tainan-based research team from National Cheng Kung University (NCKU) has discovered the pathogenesis of liver fibrosis and developed antibodies that reduce liver damage, inhibit hepatic fibrosis, and recover liver function.

Professor Ming-Shi Chang, PhD, Chair Professor of Biochemistry and Molecular Biology at NCKU, has led the team to make another breakthrough in their research on interleukin 20 (IL-20), the university revealed at a press conference on June 3.

Their research titled “IL-20 and IL-20R1 Antibodies Protect Against Liver Fibrosis” has been published in the May issue of Hepatology.

Currently, NCKU has been granted a patent in the United States of America, US 860347 B1, “Use of IL-20 Antagonists for Treating Liver Diseases”, which has attracted great interest from the biotechnology industry.
Hepatitis, fatty liver disease, and hepatotoxicity are some of the primary disorders that lead to the development of liver diseases, according to Professor Chang, who added that inflammation of the liver can evolve into liver fibrosis and cirrhosis, and that patients with liver cirrhosis at the final stage often develop liver cancer.

Inflammation is the source of many diseases, said Professor Chang. She also said that IL-20 is involved in several inflammatory diseases.

Professor Chang’s team discovered that IL-20 is an important cause of liver diseases, and they confirmed that the liver tissue of patients with liver fibrosis, liver cirrhosis, and liver cancer have significantly higher levels of IL-20. IL-20 causes liver inflammation and increases the amount of extracellular matrix, thus causing liver fibrosis and cirrhosis.

Therefore, Professor Chang went a step further by developing an antibody that inhibits IL-20, which has been tested and confirmed to effectively inhibit liver cirrhosis in mice and to attenuate the fatty liver disease resulting from the inflammation caused by the accumulation of visceral fat. The antibody also significantly recovers the liver function of mice, as attested by reduction of ALT and AST, which are the indicators of liver function.

IL-20 is a protein secreted by the human immune system, Professor Chang said. An excessive amount of IL-20 can damage body tissue and, therefore, lead to many diseases such as osteoporosis and a variety of liver diseases.

Most liver diseases result from liver damage caused by long-term chronic hepatitis. Patients with liver disease include people infected with the hepatitis B and C viruses, as well as alcoholic hepatitis and toxin-induced hepatitis.

Repeated or prolonged chronic hepatitis can seriously damage liver cells. This damage stimulates fibroblasts in the liver to produce collagen fibers, which are then deposited in the liver and fill up the empty spaces left by dead hepatocytes. Finally, this fibrosis causes liver cirrhosis.

Professor Chang and her research team observed that patients with liver fibrosis, liver cirrhosis, and liver cancer also had high levels of IL-20. After investigating this phenomenon, they discovered that IL-20 activates hepatic stellate cells and stimulates transforming growth factor (TGF)-beta1, tumor necrosis factor (TNF)-alpha, and Type I Collagen in these cells to increase the accumulation of extracellular matrix.

Because IL-20 is a protein secreted by the human body, Professor Chang and her research team developed anti-IL-20 monoclonal antibody, which inhibits the functions of IL-20 and stops IL-20-induced liver damage at the same time.

Professor Chang’s research has provided a solution to the therapeutic management of liver fibrosis and a new direction for treating liver diseases.

From the perspective of clinical medicine, anti-IL-20 monoclonal antibody could be an effective drug for treating liver fibrosis, fatty liver diseases, and liver cancer in the future.

Dr. Chang and her research team have also found that other than anti-IL-20 monoclonal antibody, monoclonal antibody that blocks the IL-20 receptor (IL-20 R1) can also protect the liver.

Liver disease is one of the most widely contracted types of diseases in Taiwan, and is widely known as one of the major types of diseases that cause a huge healthcare burden in developing countries all over the world.

At present, there is no marketed medication that can inhibit inflammation and stop liver fibrosis simultaneously.

The development of a new drug that can reverse liver fibrosis and prevent it from developing into liver cancer will benefit millions of patients with liver disease and create a huge business opportunity in the pharmaceutical sector of the world economy.

The next frontier in 3-D printing: Human organs

By Brandon Griggs, CNN
updated 9:43 AM EDT, Thu April 3, 2014

(CNN) -- The emerging process of 3-D printing, which uses computer-created digital models to create real-world objects, has produced everything from toys to jewelry to food.

Soon, however, 3-D printers may be spitting out something far more complex, and controversial: human organs.

For years now, medical researchers have been reproducing human cells in laboratories by hand to create blood vessels, urine tubes, skin tissue and other living body parts. But engineering full organs, with their complicated cell structures, is much more difficult.

Enter 3-D printers, which because of their precise process can reproduce the vascular systems required to make organs viable. Scientists are already using the machines to print tiny strips of organ tissue. And while printing whole human organs for surgical transplants is still years away, the technology is rapidly developing.

"The mechanical process isn't all that complicated. The tricky part is the materials, which are biological in nature," said Mike Titsch, editor-in-chief of 3D Printer World, which covers the industry. "It isn't like 3-D printing plastic or metal. Plastic doesn't die if you leave it sitting on an open-air shelf at room temperature for too long."

Lawrence Bonassar, a professor of biomedical engineering at Cornell University, with an artificial ear made via 3-D printing and injectable molds.

The idea of printing a human kidney or liver in a lab may seem incomprehensible, even creepy. But to many scientists in the field, bioprinting holds great promise. Authentic printed organs could be used for drug or vaccine testing, freeing researchers from less accurate methods such as tests on animals or on synthetic models.

Then there's the hope that 3-D printers could someday produce much-needed organs for transplants. Americans are living longer, and as we get deeper into old age our organs are failing more. Some 18 people die in the United States each day waiting in vain for transplants because of a shortage of donated organs -- a problem that Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine and a pioneer in bioprinting, calls "a major health crisis."

An 'exciting new area of medicine'

Bioprinting works like this: Scientists harvest human cells from biopsies or stem cells, then allow them to multiply in a petri dish. The resulting mixture, a sort of biological ink, is fed into a 3-D printer, which is programmed to arrange different cell types, along with other materials, into a precise three-dimensional shape. Doctors hope that when placed in the body, these 3-D-printed cells will integrate with existing tissues.

The process already is seeing some success. Last year a 2-year-old girl in Illinois, born without a trachea, received a windpipe built with her own stem cells. The U.S. government has funded a university-led "body on a chip" project that prints tissue samples that mimic the functions of the heart, liver, lungs and other organs. The samples are placed on a microchip and connected with a blood substitute to keep the cells alive, allowing doctors to test specific treatments and monitor their effectiveness.

"This is an exciting new area of medicine. It has the potential for being a very important breakthrough," said Dr. Jorge Rakela, a gastroenterologist at the Mayo Clinic in Phoenix and a member of the American Liver Foundation's medical advisory committee.

One of Organovo's engineers oversees the construction of a vascular tissue construct on a Novotel bioprinter.

"Three-D printing allows you to be closer to what is happening in real life, where you have multiple layers of cells," he said. With current 2-D models, "if you grow more than one or two layers, the cells at the bottom suffocate from lack of oxygen."

To accelerate the development of bioprinted organs, a Virginia foundation that supports regenerative medicine research announced in December it will award a $1 million prize for the first organization to print a fully functioning liver.

One early contender for the prize is Organovo, a California start-up that has been a leader in bioprinting human body parts for commercial purposes. Using cells from donated tissue or stem cells, Organovo is developing what it hopes will be authentic models of human organs, primarily livers, for drug testing.

The company has printed strips of human liver tissue in its labs, although they are still very small: four by four by one millimeter, or about one-fourth the size of a dime. Each strip takes about 45 minutes to print, and it takes another two days for the cells to grow and mature, said Organovo CEO Keith Murphy. The models can then survive for about 40 days.

Organovo has also built models of human kidneys, bone, cartilage, muscle, blood vessels and lung tissue, he said.

"Basically what it allows you to do is build tissue the way you assemble something with Legos," Murphy said. "So you can put the right cells in the right places. You can't just pour them into a mold."

Ethical concerns

Not everyone is comfortable with this bold new future of lab-built body parts, however.

A research director at Gartner Inc., the information-technology research and advisory firm, believes 3-D bioprinting is advancing so quickly that it will spark a major ethical debate by 2016.

A 3-D printer at Cornell University produces an artificial ear.

"Three-D bioprinting facilities with the ability to print human organs and tissue will advance far faster than general understanding and acceptance of the ramifications of this technology," Pete Basiliere said in a recent report.

"These initiatives are well-intentioned, but raise a number of questions that remain unanswered," Basiliere added. "What happens when complex 'enhanced' organs involving nonhuman cells are made? Who will control the ability to produce them? Who will ensure the quality of the resulting organs?"

Bioprinted organs are also likely to be expensive, which could put them out of reach of all but the wealthiest patients.

Murphy said Organovo only uses human cells in creating tissues, and doesn't see any ethical problems with what his company is doing.

"People used to worry about doing research on cadavers ... and that dissipated very quickly," he said. "We don't think there's any controversy if you're producing good data and helping people with health conditions."

Most experts, including Wake Forest's Atala, don't think we'll see complex 3-D-printed organs, suitable for transplants, for years if not decades. Instead, they believe the next step will be printing strips of tissue, or patches, that could be used to repair livers and other damaged organs.

Organovo also uses the Nuveen MMX Bio printer, which is small enough to fit into a cabinet.

"We are very eager to put pieces of tissue to work for surgical transplants," said Organovo's Murphy, who hopes his company will be ready to begin clinical trials within five years.

Of course, any use of 3-D-printed tissue in surgical procedures would require approval by the U.S. Food and Drug Administration. That review process could take up to a decade.

By then, the notion of a surgeon putting a 3-D-printed kidney into a patient may not seem so bizarre. Then again, this swiftly evolving technology may create new moral conundrums.

"The ethical questions are bound to be the same concerns we have seen in the past. Many major medical breakthroughs have suffered moral resistance, from organ transplants to stem cells," said Titsch of 3D Printer World.

"Will only the rich be able to afford it? Are we playing God? In the end, saving lives tends to trump all objections."

Source

Researchers take mathematical route to fighting viruses

PUBLIC RELEASE DATE: 24-Mar-2014

Contact: David Garner
david.garner@york.ac.uk
44-019-043-22153
University of York

Mathematicians at the University of York have joined forces with experimentalists at the University of Leeds to take an important step in discovering how viruses make new copies of themselves during an infection.

The researchers have constructed a mathematical model that provides important new insights about the molecular mechanisms behind virus assembly which helps to explain the efficiency of their operation.

The discovery opens up new possibilities for the development of anti-viral therapies and could help in the treatment of a range of diseases from HIV and Hepatitis B and C to the "winter vomiting bug" Norovirus and the Common Cold. The research is published in the Proceedings of the National Academy of Sciences (PNAS).

The researchers led by Professor Reidun Twarock, of the Departments of Mathematics and Biology at York, have established a theoretical basis for the speed and efficiency with which viruses assemble protective protein containers for their genetic information – in this case an RNA molecule - during an infection.

By incorporating multiple specific contacts between the genomic RNA and the proteins in the containers, and other details of real virus infections, the research team's mathematical model demonstrates how these contacts act collectively to reduce the complexity of virus formation, thus solving a longstanding puzzle about virus assembly – a form of Levinthal's Paradox. This also ensures efficient and selective packaging of the viral genome and has evolved because it provides significant selective advantages to viruses that operate this way.

Professor Twarock, a member of the York Centre for Complex Systems Analysis (YCCSA), said: "This truly interdisciplinary effort has provided surprising insights into a fundamental mechanism in virology. Existing experimental techniques for studying viral assembly are unable to identify the cooperative roles played by all the important components, highlighting the need and power of mathematical modelling. This model is a paradigm shift in the field of viral assembly. It sheds new light on virus assembly in a major class of viruses and their evolution, and opens up a novel strategy for antiviral therapy."

Professor Peter Stockley, of the Astbury Centre for Structural Molecular Biology at the University of Leeds, added: "These results provide a new perspective for our understanding of virus assembly, highlighting important features in the process that had previously been overlooked. We have already obtained proof of principle in a simple model virus that these functions can be targeted by drugs. The new opportunities for anti-viral intervention opened up by our paper also apply to viruses for which therapeutic options are currently limited. The new approach is enticing because it enables us to target co-operative aspects of viral assembly that are conserved across different viral strains, making it less likely that drug therapy would elicit resistance mutations. "

###

The research was funded by Engineering and Physical Sciences Research Council, the Biotechnology and Biological Sciences Research Council and the University of York.

Source

HIV and Hepatitis C vaccines now closer to reality

Published on March 26, 2014 at 5:01 AM

Plans for a new type of DNA vaccine to protect against the deadly HIV and Hepatitis C viruses have taken an important step forward, with University of Adelaide researchers applying for a patent based on groundbreaking new research.

Professor Eric Gowans from the University's Discipline of Surgery, based at the Basil Hetzel Institute at the Queen Elizabeth Hospital, has submitted a patent application for what he describes as a relatively simple but effective technique to stimulate the body's immune system response, thereby helping to deliver the vaccine.

While pre-clinical research into this vaccination technique is still underway, he's now searching for a commercial partner to help take it to the next stage.

Professor Gowans' work has focused on utilizing the so-called "accessory" or "messenger" cells in the immune system, called dendritic cells, to activate an immune response. These are a type of white blood cell that play a key role during infection and vaccination.

"There's been a lot of work done in the past to target the dendritic cells, but this has never been effective until now," Professor Gowans says. "What we've done is incredibly simple, but often the simple things are the best approach. We're not targeting the dendritic cells directly - instead, we've found an indirect way of getting them to do what we want."

Professor Gowans and his team have achieved this by including a protein that causes a small amount of cell death at the point of vaccination.

"The dead cells are important because they set off danger signals to the body's immune response. This results in inflammation, and the dendritic cells become activated. Those cells then create an environment in which the vaccination can be successful," Professor Gowans says.

Using a micro-needle device provided by United States company FluGen Inc., the researchers can puncture the skin to a depth of 1.5mm, delivering the vaccination directly into the skin. "We chose the skin instead of the muscle tissue, which is more common for DNA vaccines, because the skin has a high concentration of dendritic cells," Professor Gowans says.

Because the technique has the potential to translate to other, more common viruses in addition to the devastating HIV and Hepatitis C, the project attracted seed funding from The Hospital Research Foundation, and additional funding from the National Health and Medical Research Council (NHMRC).

The research is still in the pre-clinical phase, with a patient study due next year. "This technique has worked much better than I anticipated," Professor Gowans says. "We're now ready for a commercial partner to help us take this to the next phase, and we're in discussions with some potential partners at the moment."

Professor Gowans will present some of his work at the forthcoming 5th Australasian Vaccines & Immunotherapeutics Development Meeting (AVID2014), 7-9 May in Melbourne, Australia. Last month he was an invited speaker at the 23rd Australian Conference on Microscopy and Microanalysis (ACMM23) in Adelaide. A paper about this work has already been published recently in Immunology & Cell Biology.

SOURCE University of Adelaide

Source

Researchers explore transplanting stem cells to reduce inflammation in the liver

Provided by Phys.org

March 19th, 2014

University of Birmingham researchers are to lead a worldwide collaboration of scientists looking at the possibility of transplanting stem cells from one person to another to reduce inflammation in the liver.

Prof Philip Newsome and Dr Gideon Hirschfield, from the University's School of Immunity and Infection, will lead the €5.4 million Mesenchymal stem cells (MSC) to Reduce Liver Inflammation (MERLIN) programme which will include the first clinical trial of mesenchymal stem cells in liver disease in the UK.

The EU-funded programme will study how mesenchymal stem cells can reduce inflammation in the liver of people suffering from primary sclerosing cholangitis (PSC), a disease which causes inflammation and thickening of the bile ducts, build-up of bile in the liver and life-threatening liver disease.

The consortium will study how the actions of mesenchymal stem cells, which are found throughout the body including in teeth and bone marrow, can be improved and prolonged for greater clinical benefit. The consortium, which will work on this programme over the next 4 years, includes partners from the UK, Ireland, Italy, the Netherlands and the United States.

Prof Newsome said: "Gaining experience of improving the manufacture of mesenchymal stem cells and using them in this clinical trial will address a huge unmet need for treatment of PSC, which is currently incurable. It will also open up extensive opportunities for their use in other common inflammatory conditions such as rheumatoid arthritis and kidney disease."

"This will complement our other ongoing studies of cell therapy, consolidating Birmingham's position as a world-leading centre for cutting-edge clinical trials of novel therapies."

Provided by University of Birmingham

This Phys.org Science News Wire page contains a press release issued by an organization mentioned above and is provided to you “as is” with little or no review from Phys.Org staff.

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Chronic hepatitis C virus infection: it is not only about the liver

Eur J Gastroenterol Hepatol. 2014 Mar;26(3):313-8. doi: 10.1097/MEG.0b013e328362dbff.

Vigani AG¹, Tozzo R, Quezada A, Diaz AC, Mendes L, Lopes I, Riberio E, Espindola GM, Lopes FP, Petoilho EC, Queiroz JL, Castro HM.

Abstract

BACKGROUND AND AIMS: Although hepatitis B virus (HBV) and hepatitis C virus (HCV) are both hepatotropic and quite similar in terms of clinical manifestations and histopathology, their respective infections are distinct in terms of epidemiology and prognosis. Recognizing the differences between patients with HBV and HCV infection with respect to demographic characteristics, prevalence of comorbidities, and presence of lifestyle factors aids the proper treatment of these patients. We aimed to compare two populations with chronic viral liver disease (chronic HCV and chronic HBV), each of them with resolved hepatitis C.

PATIENTS AND METHODS: We included patients referred to a municipal reference clinic from March 2009 through May 2012. Patient data were collected using standardized questionnaires at the patients' first visit to clinic. Questionnaires included epidemiological information, presence of comorbidities, and lifestyle.

RESULTS: A total of 756 patients were included in the study, 348 (46.0%) with chronic HCV infection, 176 (23.3%) with chronic HBV infection, and 232 (30.7%) with resolved HCV infection. Multivariate analysis including patients with chronic HCV infection and chronic HBV infection indicated that age [adjusted odds ratio (AOR)=1.06; 95% confidence interval (CI): 1.03-1.08], alcohol abuse (AOR=1.58; 95% CI: 1.01-2.49), smoking (AOR=1.64; 95% CI: 1.00-2.17), and illicit drug (AOR=2.92; 95% CI: 1.69-5.02) use were associated independently with chronic HCV infection. Multivariate analyses including patients with chronic HCV infection and those patients with resolved HCV infection, presence of at least one comorbidity (AOR=1.94; 95% CI: 1.12-3.3), illicit drug use (AOR=3.24; 95% CI: 1.90-5.54), and age (AOR=1.03; 95% CI: 1.01-1.05) were independently associated with chronic HCV infection. Age (AOR=0.98; 95% CI: 0.96-0.99) and male sex (AOR=1.93; 95% CI: 1.26-2.95) were the only variables associated significantly with chronic HBV infection in the multivariate analysis between patients with chronic HBV infection and resolved HCV infection.

CONCLUSION: Our results highlight that patients with chronic HCV infection are complex and require a multidisciplinary approach during patient follow-up and clinical management.

PMID: 23719563 [PubMed - in process]

Source

Racial Disparities in the Proportion of Current, Unresolved Hepatitis C Virus Infections in the United States, 2003-2010

Dig Dis Sci. 2014 Feb 27. [Epub ahead of print]

Liu G¹, Holmberg SD, Kamili S, Xu F.

Abstract

BACKGROUND: The hepatitis C virus (HCV) antibody test alone does not distinguish current from resolved infections.

AIM: The study aimed to describe the percentage of current HCV infection, defined by HCV RNA positivity, among those tested positive for anti-HCV, and to examine characteristics of those with current infection.

METHODS: Using nationally representative data from the 2003 to 2010 National Health and Nutrition Examination Surveys, descriptive analyses and regressions were performed on data from anti-HCV-positive adults aged ≥40 years.

RESULTS: Of 13,909 participants examined, 304 were anti-HCV-positive. Of these, 238 or 75.3 % [95 % confidence interval (CI) 67.5-81.8 %] had detectable viral RNA. The percentage of current, unresolved HCV infection was highest among non-Hispanic Blacks (91.1 %) and lowest among those with a college education (57.3 %). In multivariate analyses, non-Hispanic Blacks were more likely to have current HCV infection compared to non-Hispanic Whites (adjusted odds ratio 3.9, 95 % CI 1.6-9.2). Among persons with current HCV infection, most had elevated alanine aminotransferase (56.5 %) or aspartate aminotransferase (71.8 %) levels, but only 35.3 % reported having been diagnosed with any abnormal liver conditions. Excessive alcohol drinking was reported by 27.3 % of participants with current HCV infection.

CONCLUSIONS: Among adults aged ≥40 years who had ever been infected with HCV, approximately three-quarters had current, unresolved HCV infection. Non-Hispanic Blacks were more likely to have current infection than non-Hispanic Whites. The majority of those with current infection had abnormal liver function tests but had not received appropriate diagnoses. Many currently infected persons would benefit from lifestyle modifications to avoid the multiplicative effect of alcohol on HCV infection.

PMID: 24573716 [PubMed - as supplied by publisher]

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Scientists Transform Skin Cells into Functioning Liver Cells

Joint Gladstone-UCSF Study Highlights Novel Reprogramming Method, Offers New Hope for Treating Liver Failure

By Jeff Norris and Anne Holden on February 23, 2014

The power of regenerative medicine now allows scientists to transform skin cells into cells that closely resemble heart cells, pancreas cells and even neurons. However, a method to generate cells that are fully mature—a crucial prerequisite for life-saving therapies—has proven far more difficult. But now, scientists at the Gladstone Institutes and UC San Francisco have made an important breakthrough: they have discovered a way to transform skin cells into mature, fully functioning liver cells that flourish on their own, even after being transplanted into laboratory animals modified to mimic liver failure.

Holger Willenbring, MD, PhD

In previous studies on liver-cell reprogramming, scientists had difficulty getting stem cell-derived liver cells to survive once being transplanted into existing liver tissue. But the Gladstone-UCSF team figured out a way to solve this problem. Writing in the latest issue of the journal Nature, researchers in the laboratories of Gladstone Senior Investigator Sheng Ding, PhD, and UCSF Associate Professor Holger Willenbring, MD, PhD, reveal a new cellular reprogramming method that transforms human skin cells into liver cells that are virtually indistinguishable from the cells that make up native liver tissue.

These results offer new hope for the millions of people suffering from, or at risk of developing, liver failure—an increasingly common condition that results in progressive and irreversible loss of liver function. At present, the only option is a costly liver transplant. So, scientists have long looked to stem cell technology as a potential alternative. But thus far they have come up largely empty-handed.

Sheng Ding, PhD

“Earlier studies tried to reprogram skin cells back into a pluripotent, stem cell-like state in order to then grow liver cells,” explained Ding, one of the paper’s senior authors, who is also a professor of pharmaceutical chemistry at UCSF, with which Gladstone is affiliated. “However, generating these so-called induced pluripotent stem cells, or iPS cells, and then transforming them into liver cells wasn’t always resulting in complete transformation. So we thought that, rather than taking these skin cells all the way back to a pluripotent, stem cell-like state, perhaps we could take them to an intermediate phase.”

This research, which was performed jointly at the Roddenberry Center for Stem Cell Research at Gladstone and the Broad Center of Regeneration Medicine and Stem Cell Research at UCSF, involved using a ‘cocktail’ of reprogramming genes and chemical compounds to transform human skin cells into cells that resembled the endoderm. Endoderm cells are cells that eventually mature into many of the body’s major organs—including the liver.

“Instead of taking the skin cells back to the beginning, we took them only part way, creating endoderm-like cells,” added Gladstone and CIRM Postdoctoral Scholar Saiyong Zhu, PhD, one of the paper’s lead authors. “This step allowed us to generate a large reservoir of cells that could more readily be coaxed into becoming liver cells.”

Next, the researchers discovered a set of genes and compounds that can transform these cells into functioning liver cells. And after just a few weeks, the team began to notice a transformation.

“The cells began to take on the shape of liver cells, and even started to perform regular liver-cell functions,” said UCSF Postdoctoral Scholar Milad Rezvani, MD, the paper’s other lead author. “They weren’t fully mature cells yet—but they were on their way.”

Now that the team was encouraged by these initial results in a dish, they wanted to see what would happen in an actual liver. So, they transplanted these early-stage liver cells into the livers of mice. Over a period of nine months, the team monitored cell function and growth by measuring levels of liver-specific proteins and genes.

Two months post-transplantation, the team noticed a boost in human liver protein levels in the mice, an indication that the transplanted cells were becoming mature, functional liver cells. Nine months later, cell growth had shown no signs of slowing down. These results indicate that the researchers have found the factors required to successfully regenerate liver tissue.

“Many questions remain, but the fact that these cells can fully mature and grow for months post-transplantation is extremely promising,” added Willenbring, associate director of the UCSF Liver Center and the paper’s other senior author. “In the future, our technique could serve as an alternative for liver-failure patients who don’t require full-organ replacement, or who don’t have access to a transplant due to limited donor organ availability.”

Other scientists who participated in this research include UCSF researchers Jack Harbell, MD, also a lead author on the paper, as well as Aras Mattis, MD, PhD, Alan Wolfe and Leslie Benet, PhD. Funding was provided by the following: the California Institute for Regenerative Medicine, the National Institutes of Health, the German Academic Exchange Service, and the Society of University Surgeons.

About the Gladstone Institutes

Gladstone is an independent and nonprofit biomedical-research organization dedicated to accelerating the pace of scientific discovery and innovation to prevent, treat and cure cardiovascular, viral and neurological diseases. Gladstone is affiliated with UCSF.

About UCSF

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy, a graduate division with nationally renowned programs in basic biomedical, translational and population sciences, as well as a preeminent biomedical research enterprise and two top-ranked hospitals, UCSF Medical Center and UCSF Benioff Children’s Hospital.

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Rutgers scientists identify structure of virus that could lead to hepatitis C vaccine

PUBLIC RELEASE DATE: 19-Feb-2014

Contact: Robin Lally
rlally@ucm.rutgers.edu  
848-932-0557
Rutgers University

Infection is a major global health problem affecting 160 million people worldwide

This is Joseph Marcotrigiano, associate professor of chemistry and chemical biology, Rutgers University. Credit: Nick Romanenko, Rutgers University

Rutgers University scientists have determined the structure of a hepatitis C surface protein, a finding that could assist in the development of a vaccine to halt the spread of the the deadly disease that has infected 3.2 million Americans.

Joseph Marcotrigiano, associate professor of chemistry and chemical biology, says this new research – published online today in Nature – describes an outer region of hepatitis C that enables the virus to evade the body's natural immune system response, causing persistent, chronic infection.

Hepatitis C is constantly mutating, allowing it to infect a host cell and evade the immune responses, causing chronic infection that can be difficult to treat. By identifying the structure of virus's outer protein, Marcotrigiano, the study's lead author, says scientists will be better able to develop a vaccine that targets the immune system to vulnerable regions of the virus in order to prevent infection.

"Viruses are smart and it is a constant battle to keep them out," says Marcotrigiano who collaborated on the research with colleagues from the Center for Advanced Biotechnology and Medicine at Rutgers and Emory University School of Medicine. "That's why the development of a vaccine is so important. It's always better to prevent infection through an effective vaccine then to treat after a chronic infection has been established."

Hepatitis C virus is a major global health problem with 160 million people infected throughout the world, about four times more individuals than those with HIV. Most of those infected do not show symptoms until the virus – the number one cause of liver transplantation – has caused severe liver damage.

The virus is mainly spread through contact with an infected person's blood, such as sharing of needles. Prior to 1992, when donated blood began being tested, the virus was also spread through blood transfusions and organ donation.

Recently, the Food and Drug Administration approved several new drugs that could cure many patients infected with hepatitis C in as little as 12 weeks. However, at about $1000 per pill, this may not be a cost-effective solution to hepatitis C virus.

Developing a vaccine against hepatitis C would not only prevent people from acquiring the disease, Marcotrigiano says, but would also be the most cost-conscious health intervention.

Michael Houghton, a researcher at the University of Alberta in Canada, has been developing a vaccine that is currently being tested clinically. Houghton, who led a team that discovered the hepatitis C virus in 1989, says the Rutgers finding is important because knowing the structure of the virus will help in the development of a vaccine that enables the immune system to produce more infection-fighting antibodies that can neutralize the virus.

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New nanoparticles offer best-ever gene silencing, could help treat liver diseases

Posted: Feb 11, 2014

(Nanowerk News) Inspired by tiny particles that carry cholesterol through the body, MIT chemical engineers have designed nanoparticles that can deliver snippets of genetic material that turn off disease-causing genes.

This approach, known as RNA interference (RNAi), holds great promise for treating cancer and other diseases. However, delivering enough RNA to treat the diseased tissue, while avoiding side effects in the rest of the body, has proven difficult.

The new MIT particles, which encase short strands of RNA within a sphere of fatty molecules and proteins, silence target genes in the liver more efficiently than any previous delivery system, the researchers found in a study of mice.

“What we’re excited about is how it only takes a very small amount of RNA to cause gene knockdown in the whole liver. The effect is specific to the liver — we get no effect in other tissues where you don’t want it,” says Daniel Anderson, the Samuel A. Goldblith Associate Professor of Chemical Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research.

Anderson is senior author of a paper describing the particles in the Proceedings of the National Academy of Sciences ("Lipopeptide nanoparticles for potent and selective siRNA delivery in rodents and nonhuman primates") the week of Feb. 10. Robert Langer, the David H. Koch Institute Professor at MIT, is also an author.

MIT engineers designed nanoparticles that can deliver short strands of RNA (green) into cells (nuclei are stained blue). (Image: Gaurav Sahay, Yizhou Dong, and Omid Veiseh)

The research team, which included scientists from Alnylam Pharmaceuticals, also found that the nanoparticles could powerfully silence genes in nonhuman primates. The technology has been licensed to a company for commercial development.

Natural inspiration

RNA interference is a naturally occurring phenomenon that scientists have been trying to exploit since its discovery in 1998. Snippets of RNA known as short interfering RNA (siRNA) turn off specific genes inside living cells by destroying the messenger RNA molecules that carry DNA’s instructions to the rest of the cell.

Scientists hope this approach could offer new treatments for diseases caused by single mutations, such as Huntington’s disease, or cancer, by blocking mutated genes that promote cancerous behavior. However, developing RNAi therapies has proven challenging because it is difficult to deliver large quantities of siRNA to the right location without causing side effects in other tissues or organs.

In previous studies, Anderson and Langer showed they could block multiple genes with small doses of siRNA by wrapping the RNA in fatlike molecules called lipidoids. In their latest work, the researchers set out to improve upon these particles, making them more efficient, more selective, and safer, says Yizhou Dong, a postdoc at the Koch Institute and lead author of the paper.

“We really wanted to develop materials for clinical use in the future,” he says. “That’s our ultimate goal for the material to achieve.”

The design inspiration for the new particles came from the natural world — specifically, small particles known as lipoproteins, which transport cholesterol and other fatty molecules throughout the body.

Like lipoprotein nanoparticles, the MIT team’s new lipopeptide particles are spheres whose outer membranes are composed of long chains with a fatty lipid tail that faces into the particle. In the new particles, the head of the chain, which faces outward, is an amino acid (the building blocks of proteins). Strands of siRNA are carried inside the sphere, surrounded by more lipopeptide molecules. Molecules of cholesterol embedded in the membrane and an outer coating of the polymer PEG help to stabilize the structure.

The researchers tuned the particles’ chemical properties, which determine their behavior, by varying the amino acids included in the particles. There are 21 amino acids found in multicellular organisms; the researchers created about 60 lipopeptide particles, each containing a different amino acid linked with one of three chemical groups — an acrylate, an aldehyde, or an epoxide. These groups also contribute to the particles’ behavior.

David Putnam, an associate professor of biomedical engineering at Cornell University, says he is impressed with the team’s approach to mimicking how the body transports fatty molecules with lipoprotein particles.

“They hijacked that machinery and made something that looks like the lipoprotein structures and will carry siRNA straight to the liver. They’re building on Mother Nature and making it as efficient as possible,” says Putnam, who was not part of the research team.

Targeted strike

The researchers then tested the particles’ ability to shut off the gene for a blood clotting protein called Factor VII, which is produced in the liver by cells called hepatocytes. Measuring Factor VII levels in the bloodstream reveals how effective the siRNA silencing is.

In that initial screen, the most efficient particle contained the amino acid lysine linked to an epoxide, so the researchers created an additional 43 nanoparticles similar to that one, for further testing. The best of these compounds, known as cKK-E12, achieved gene silencing five times more efficiently than that achieved with any previous siRNA delivery vehicle.

In a separate experiment, the researchers delivered siRNA to block a tumor suppressor gene that is expressed in all body tissues. They found that siRNA delivery was very specific to the liver, which should minimize the risk of off-target side effects.

“That’s important because we don’t want the material to silence all the targets in the human body,” Dong says. “If we want to treat patients with liver disease, we only want to silence targets in the liver, not other cell types.”

In tests in nonhuman primates, the researchers found that the particles could effectively silence a gene called TTR (transthyretin), which has been implicated in diseases including senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy.

The MIT team is now trying to learn more about how the particles behave and what happens to them once they are injected, in hopes of further improving the particles’ performance. They are also working on nanoparticles that target organs other than the liver, which is more challenging because the liver is a natural destination for foreign material filtered out of the blood.

Source: By Anne Trafton, MIT

Source

Newly found tactics in offense-defense struggle with hepatitis C virus

PUBLIC RELEASE DATE: 7-Feb-2014

Contact: Leila Gray
leilag@uw.edu
206-685-0381
University of Washington

This is a schematic on the window board of Dr. Ram Savan's lab at UW Medicine South Lake Union in Seattle. The schematic outlines how a genetic variant produces a robust antiviral response to the hepatitis C virus. Credit: Ram Savan/University of Washington

The hepatitis C virus (HCV) has a previously unrecognized tactic to outwit antiviral responses and sustain a long-term infection. It also turns out that some people are genetically equipped with a strong countermeasure to the virus' attempt to weaken the attack on it.

The details of these findings suggest potential targets for treating HCV, according to a research team led by Dr. Ram Savan, assistant professor of immunology at the University of Washington. The study was published in Nature Immunology.

HCV infects more than 150 million of the world's people. The virus is notorious for evading the body's immune system and establishing an infection that can continue for decades, despite treatment. A lasting infection can damage the liver, and in some cases produce liver cancer. HCV infection is a major cause of liver failure requiring an organ transplant.

The virus, hiding in other tissues, can return in the transplanted liver. HCV and the human immune system are engaged in a seemingly never-ending duel, each trying to overcome the others latest move. Several HCV mechanisms for defying the body's immune system have already been uncovered.

Present treatments are about 70 percent effective in curing the infection, Savan said. The triple combination treatments consist of interferon, ribavirin and direct-acting antiviral agents.

He added, however, that resistant strains of HCV are emerging in antiviral treated patients. Also troubling, he said, is that certain patients can undergo almost a year of treatment weeks – and still be infected. They've endured the unpleasant, flu-like side effects of the regimen with little benefit.

After observing that patients of Asian descent reacted better to HCV treatment than did those of African descent, other research teams searched entire human genomes to identify gene clusters associated with response to therapy.

On chromosome 19, the scientists found different, single-letter DNA code changes linked to treatment response and the natural ability to clear HCV infection.

These tiny genetic variations are located near an area that encodes for interferon-lamda3 (IFNL3), also called interleukin-28B. Viruses can trigger blood cells and other cells to produce this potent substance, which is released to protect against virus invasion.

The mechanism aligning this genetic finding with clearance of HCV had been elusive, Savan's group noted in their paper. His team discovered how the single-letter variation in the IFNL3 gene was responsible for the differences between those who could and those who could not effectively clear HCV.

Individuals who carry the T (for thymidine) variant have an unfavorable outcome in fighting HCV, while those who carry the G (for guanosine) variant have a favorable outcome.

Their data showed that HCV could induce liver cells to target the activities of the IFNL3 gene with two microRNAs. MicroRNAs are silencers: They stop the messengers who transmit information to produce a protein from a gene, in this case the production of the antiviral interferon lambda-3.

These two particular microRNAs are generally turned off in liver cells, until HCV coerces them to act on its behalf. Normally, these so called myomiRs are associated with myosin-encoding genes in skeletal and heart muscle.

"This is a previously unknown strategy by which HCV evades the immune system and suggests that these microRNAs could be therapeutic targets for restoring the host antiviral response," the researchers wrote in their paper. Adding support to this suggestion is the researchers' observation that the bad-acting microRNAs in question could not land on and repress interferon lambda-3, if the host carried the favorable "G" variant.

In those cases, the host is able to escape adverse regulation by HCV, the researchers observed. Savan pointed out that this particular escape variant has been found only in humans, and not in other primates. He said it is not yet known if the G variant arose in humans as a response to selective pressure by infection with HCV.

###

Savan came to the University of Washington in late 2011 from the National Institutes of Health. The first author on the paper, Adelle McFarland, was a research scientist in Savan's lab and is now a graduate student in the Molecular and Cellular Biology Program at the UW.

Funding for this project came from a start-up grant from the UW Department of Immunology and from the National Institutes of Health (HHSN261200800001E, AI060389, AI88778, and CA148068)

Other researchers on the project, reported in the article "The favorable IFNL3 genotype escapes mRNA decay mediated by AU-rich elements and hepatitis C virus-induced microRNAS," were Stacy M. Horner, Abigail Jarret, Rochelle C. Joslyn, all at the UW Department of Immunology at the time of the study; Eckart Bindewald and Mary Carrington of the Frederick National Laboratory for Cancer Research, Bruce A. Shapiro of the National Cancer Institute, and Don A. Delker and Curt H. Hagedorn, both of the University of Utah. Michael Gale, Jr., a collaborator in this study, is from the UW department of Immunology.

A Nature Immunology News & Views commentary, "Outflanking HCV." by Zhigang Tian of the University Of Life Sciences Of China in Hefei, gives a perspective on the research findings.

Source

BPA Exposure in Womb Linked with Liver Tumors

Provided by Nature World News

By Staff Reporter Feb 03, 2014 06:13 AM EST

mice exposed to BPA have high risk of liver tumors. (not pictured) (Photo : REUTERS/Asmaa Waguih)

University of Michigan School of Public Health researchers found liver tumors in mice whose mothers were exposed to the chemical BPA.

Bisphenol A or BPA is a chemical used in plastics and epoxy resins. The chemical is found in many products including water bottles, cups and impact resistant material. Compact discs Epoxy resin is used to coat metal products such as food cans, bottles and cup.

Previous research has shown that BPA can affect fertility in animals. A related study on mice had linked the chemical with prostate cancer in the rodents.

The study shows a direct link between BPA and cancer. The mice in the study were exposed to the chemical during gestation and nursing.

For the study, researchers fed female mice with food containing BPA. These mice were then allowed to mate and were given one of three chemical doses (50 µg, or 50 mg of BPA per kg diet) during gestation and nursing.

The scientists then followed one male and female mouse from each litter and tracked their growth for ten months.

They found that mice whose mothers were exposed to 50 mg of BPA per kg diet had seven times higher risk of developing liver tumor than other non-exposed mice.

"We found that 27 percent of the mice exposed to one of three different doses of BPA through their mother's diet developed liver tumors and some precancerous lesions. The higher the dosage, the more likely they were to present with tumors," said Caren Weinhouse, U-M doctoral student in the School of Public Health's Department of Environmental Health Sciences and first author of the paper, according to a news release.

Also, researchers found that BPA didn't discriminate between male and female. "In general, females are at lower risk of spontaneous development of liver cancer," she said in a news release. "That distinction was erased in this study, with both males and females showing tumors."

The study is published in the journal Environmental Health Perspectives.

Source

Scientists hail breakthrough in embryonic-like stem cells

BY KATE KELLAND, HEALTH AND SCIENCE CORRESPONDENT
LONDON Thu Jan 30, 2014 1:29pm EST

A mouse embryo formed with Stimulus-Triggered Acquisition of Pluripotency (STAP) cells is seen in this undated image released by RIKEN Center for Developmental Biology on January 28, 2014.
CREDIT: REUTERS/HARUKO OBOKATA/RIKEN CENTER FOR DEVELOPMENTAL BIOLOGY/HANDOUT VIA REUTERS

(Reuters) - In experiments that could open a new era in stem cell biology, scientists have found a simple way to reprogram mature animal cells back into an embryonic-like state that allows them to generate many types of tissue.

The research, described as game-changing by experts in the field, suggests human cells could in future be reprogrammed by the same technique, offering a simpler way to replace damaged cells or grow new organs for sick and injured people.

Chris Mason, chair of regenerative medicine bioprocessing at University College London, who was not involved in the work, said its approach in mice was "the most simple, lowest-cost and quickest method" to generate so-called pluripotent cells - able to develop into many different cell types - from mature cells.

"If it works in man, this could be the game changer that ultimately makes a wide range of cell therapies available using the patient's own cells as starting material - the age of personalized medicine would have finally arrived," he said.

The experiments, reported in two papers in the journal Nature on Wednesday, involved scientists from the RIKEN Center for Developmental Biology in Japan and Brigham and Women's Hospital and Harvard Medical School in the United States.

The researchers took skin and blood cells, let them multiply, then subjected them to stress "almost to the point of death", they explained, by exposing them to various events including trauma, low oxygen levels and acidic environments.

One of these "stressful" situations was simply to bathe the cells in a weak acid solution for around 30 minutes.

Within days, the scientists found that the cells had not only survived but had also recovered by naturally reverting into a state similar to that of an embryonic stem cell.

These stem cells - dubbed Stimulus-Triggered Acquisition of Pluripotency, or STAP, cells by the researchers - were then able to differentiate and mature into different types of cells and tissue, depending on the environments they were put in.

"NEW ERA"

"If we can work out the mechanisms by which differentiation states are maintained and lost, it could open up a wide range of possibilities for new research and applications using living cells," said Haruko Obokata, who lead the work at RIKEN.

Stem cells are the body's master cells and are able to differentiate into all other types of cells. Scientists say that by helping to regenerate tissue and potentially grow new organs, they could offer ways of tackling diseases for which there are currently only limited treatments.

Recent experimental research has seen stem cells used to create a functional human liver and to create beating heart muscle tissue.

There are two main types of stem cells: embryonic ones, harvested from embryos, and adult or iPS cells, which are taken from skin or blood and reprogrammed back into stem cells.

Because the harvesting of embryonic stem cells requires the destruction of a human embryo, the technique has been the subject of ethical concerns and protests from pro-life campaigners.

Dusko Ilic, a reader in stem cell science at Kings College London, said the Nature studies described "a major scientific discovery" and predicted their findings would open "a new era in stem cell biology".

"Whether human cells would respond in a similar way to comparable environmental cues ... remains to be shown," he said in an emailed comment. "I am sure that the group is working on this and I would not be surprised if they succeed even within this calendar year."

Robin Lovell-Badge, a stem cell expert at Britain's National Institute for Medical Research, said it would be some time before the exact nature and capabilities of the STAP cells would be fully understood by scientists - and only then would their full potential in medicine become clearer.

"But the really intriguing thing to discover will be the mechanism underlying how a low pH shock triggers reprogramming," he said. "And why does it not happen when we eat lemon or vinegar, or drink cola?"

(Editing by Kevin Liffey)

Source

Mount Sinai researchers identify UHRF1 as oncogene driving liver cancer

PUBLIC RELEASE DATE: 30-Jan-2014

Contact: Laura Newman
laura.newman@mountsinai.org
212-241-9200
The Mount Sinai Hospital / Mount Sinai School of Medicine

Finding spurs R&D into epigenetic-modifying drugs for this lethal disease

This shows a 5-day old zebrafish expressing green fluorescent protein in hepatocytes (liver cells) to highlight the liver.

New York, NY – Patients with advanced hepatocellular (or liver) cancer have high mortality rates, with existing drugs demonstrating only a small, but significant survival advantage. By combining a zebrafish model of liver cancer with data from human tumors, researchers from the Icahn School of Medicine at Mount Sinai hope to identify potential genes of interest that can be targeted for new treatments for hepatocellular carcinoma, the most common form of liver cancer to develop from liver cells.

Using transgenic zebrafish as an emerging, powerful whole animal model for cancer gene discovery, in combination with cultured cells and data from human tumors, they found that a gene called UHRF1, which is highly expressed in many types of cancers, can cause liver cancer at an unprecedented rate and incidence – with tumors forming in 75% of fish within 20 days. Results from the study are published online in the journal Cancer Cell.

"This is the first time that UHRF1 has been shown to be sufficient on its own to cause any kind of cancer when it is highly expressed," said the study's senior investigator, Kirsten C. Sadler, PhD, Associate Professor Medicine in the Division of Liver Diseases and of Developmental and Regenerative Biology, and Director of the Zebrafish Research Facility at the Icahn School of Medicine at Mount Sinai. UHRF1 has generated a lot of interest because it is a central regulator of epigenome – which is a collection of reversible modifications to DNA and the DNA packaging proteins – that are important for deciding which genes are expressed and how the DNA is transmitted during cell division. The cancer cell epigenome is dramatically different from normal cells, and the field of cancer epigenetics is exploding because of the hope that these changes could be reversed, and thereby reverse the aggressive nature of cancer cells. "Down the road, we hope to develop drugs to target UHRF1 and thereby reset the cancer epigenome to activate anti-tumor mechanisms and halt liver cancer.," added Dr. Sadler.

\UHRF Levels Important in Human Liver Cancers, Too

When the team analyzed patient-derived liver tumors, they found that high levels of the UHRF1 were also found there, too. Most strikingly, the changes in gene expression caused by high UHRF1 levels in zebrafish were reflected in the human tumors expressing high UHRF1 levels. This points to similar mechanisms underlying UHRF1-driven liver tumor formation in both species. One of these is the ability of the cancer-prone cells to bypass the tumor suppressive mechanisms that are activated in most cells when they receive a cancer-causing stimulus.

Cellular senescence is one such mechanism, and this study found that tumors associated with UHRF1 levels in both fish and humans only those cells that could escape senescence were the ones that could go on to form the tumors. This lays the groundwork to use this model to test new therapies that would target UHRF1 to re-activate the senescence program and halt cancer formation.

Dr. Sadler pointed to several advantages of using zebrafish in preclinical liver disease research. Zebrafish reproduce rapidly and abundantly, they are translucent until about three weeks of age, enabling researchers to directly visualize tumor growth, and the cells in the liver function similarly to those in humans. Zebrafish are also inexpensive to raise, making this study uniquely powerful, as they analyzed nearly 300 fish for tumors in this study– a scope that would be extremely costly using traditional mammalian cancer models.

UHRF1 is overexpressed in around 40%-50% hepatocellular cancers in humans and predict poor outcome. This overexpression is associated with poorer prognosis in terms of high recurrence rate and low term overall survival. "We have little to offer people in the setting of advanced disease – and this points to an entirely new direction," Dr. Sadler said. "It raises the hope that epigenetic drugs could be applied to liver cancer in the future."

Commenting on the research, Scott Friedman, MD, Dean for Therapeutic Discovery, and Fishberg Professor of Medicine, and Chief of the Division of Liver Diseases, at the Icahn School of Medicine at Mount Sinai, said: "Dr. Sadler's team has conducted a remarkable study that combines the power of the zebrafish model with state of the art genomic analysis of a devastating and poorly treated human cancer. This kind of comprehensive study not only uncovers a new approach to treating hepatocellular carcinoma, but also provides a vital roadmap to unlocking cancer's secrets more quickly and effectively."

The need for better treatments for hepatocellular cancer was underscored by Josep M. Llovet, MD, a study coauthor, and Professor of Medicine, and Director, Mount Sinai Liver Cancer Program. "The incidence of hepatocellular cancer is increasing worldwide and the median outcome at advanced stages with the sole effective molecule available, Sorafenib, is one year. Thus, identification of novel targets for HCC therapies are an unmet medical need. The current study points to the fact that UHRF1 is an oncogene driver and a potential target for therapies"

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Other researchers contributing to this research from the Icahn School of Medicine at Mount Sinai were Raksha Mudbhary, Yujin Hoshida, Yelena Chernyavskaya, Vinitha Jacob, M. Isabel Fiel, Xintong Chen, Kensuke Kojima, Swan Thung, Anja Lachenmayer, Kate Revill, Ravi Sachidananandam, and Josep M. Llovet. The research team also included investigators from Harvard Medical School's Brigham and Women's Hospital and the IDIBAPS- Hospital Clínic and Institucio Catalana de Recerca, in Barcelona Spain.

About Cancer Gene Discovery in Zebrafish

Researchers in the Liver Cancer Research Program at the Icahn School of Medicine at Mount Sinai use genetic approaches in live zebrafish and in cultured human cancer cells. They collaborate with translational researchers to exploit data from human tumors to identify novels targets for treating hepatocellular carcinoma.

About the Mount Sinai Health System

The Mount Sinai Health System is an integrated health system committed to providing distinguished care, conducting transformative research, and advancing biomedical education. Structured around seven member hospital campuses and a single medical school, the Health System has an extensive ambulatory network and a range of inpatient and outpatient services—from community-based facilities to tertiary and quaternary care.

The System includes approximately 6,600 primary and specialty care physicians, 12-minority-owned free-standing ambulatory surgery centers, over 45 ambulatory practices throughout the five boroughs of New York City, Westchester, and Long Island, as well as 31 affiliated community health centers. Physicians are affiliated with the Icahn School of Medicine at Mount Sinai, which is ranked among the top 20 medical schools both in National Institutes of Health funding and by U.S. News & World Report.

For more information, visit http://www.mountsinai.org. Find Mount Sinai on: Facebook: http://www.facebook.com/mountsinainyc Twitter @mountsinainyc YouTube:http://www.youtube.com/mountsinainy

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