‘Humanized' mice is latest MIT medical breakthrough

A team led by Sangeeta Bhatia, a biomedical engineer at the Massachusetts Institute of Technology in Cambridge, made 20-millimetre-long artificial human livers and implanted them into otherwise normal mice. The researchers report today in Proceedings of the National Academy of Sciences that the mice showed metabolism characteristic of the human liver for weeks after implantation.

Although scientists commonly use mice for biomedical research, they are not always helpful for pharmaceutical testing. Because mouse livers react to drugs differently than human livers, they often can't be used to predict whether a potential drug will be toxic to people. That means that a drug that harms the liver could make it all the way to human clinical trials before researchers discover its risks.

"What's exciting to researchers is this idea that if we can create these mice with human livers, we can basically create a slew of human-like patients to do drug-development screens, or to ... develop new therapies," says Alice Chen, an author on the study who works in the lab of Sangeeta Bhatia, the John and Dorothy Wilson Professor of HST and Electrical Engineering and Computer Science.

"The key technique is that we make stable liver implants in the laboratory first," says biomedical engineer Chen The researchers combined human liver cells (hepatocytes) that carry out the liver's metabolic functions, with mouse fibroblast cells and human liver endothelial cells, which provide chemical signals the hepatocytes need to function. They encased the cell packages in a plastic scaffold and implanted them into mice.

When they gave the mice drugs that humans and mice break down differently, the mice produced the same breakdown products (metabolites) and showed the same metabolic interactions between drugs as a human would. The authors hope that the new technology will make drug development safer and less costly, by spotting toxicities before a drug gets to clinical trials.


You can read more of this fascinating story here and here

Gene therapy offers hope for Parkinson's disease

An experimental gene-therapy treatment for Parkinson's disease has eased the movement problems of a small number of patients and raised no major safety concerns. The study, reported in The Lancet Neurology¹, is the first double-blind clinical trial to show a benefit of gene therapy to patients with the neurodegenerative condition.

Parkinson's disease is characterized by tremors, slowness and cognitive problems, and is caused by the death of neurons in brain circuits that makes dopamine. The effects cascade through interconnected brain regions involved in movement, with some areas becoming overactive.

Many patients are treated with the drug levadopa (L-DOPA), a chemical precursor of dopamine, and regain control of their movements. Over time, however, patients become less sensitive to L-DOPA and burdened by its side effects, which include psychological and physical problems.

Long-term fix

Gene therapy could offer a longer-lasting solution, says Andrew Feigin, a neurologist at the Feinstein Institute for Medical Research in Manhasset, New York, who led the trial along with Michael Kaplitt, at Weill Cornell Medical College in New York and Matthew During, at Ohio State University in Columbus. This involved 45 patients aged between 30 and 75 years old, and was funded by Neurologix of Fort Lee, New Jersey, which holds the patent for the therapy.

Half of the patients received an infusion of a virus engineered to deliver a gene called glutamic acid decarboxylase (GAD) into a brain centre that is overactive in Parkinson's disease — the subthalamic nucleus. GAD encodes a neurotransmitter called GABA, which quiets neurons in this area. Another treatment for Parkinson's, deep brain stimulation (DBS), uses electricity to silence neurons in the same region.

The remaining patients underwent brain surgery, but did not receive the gene therapy.

Six months after these surgeries, Feigin's team measured improvements in both sets of patients using a standardized assessment of Parkinson's disease that looks at factors such as gait, posture, and hand and finger movements. Patients who had received the gene therapy exhibited a 23.1% improvement on this scale, compared with a 12.7% boost for patients who had undergone the placebo surgery. However, patients given the gene therapy did not, as a whole, see any more quality-of-life benefits than the other group.

Feigin's team excluded six patients who may not have received the gene therapy because of problems in its delivery. He says that this is justifiable in a small trial intended to test whether or not a treatment works. "If you included people who didn't get the therapy it could easily wash out the benefit you might see," he says.

In safe hands

One patient who received the gene therapy required treatment for a bowel obstruction 4 months after surgery, but Feigin says this was not related to the therapy.

"I'm very excited to see that it's safe," says Stéphane Palfi, a neurosurgeon at Henri Mondor Hospital in Creteil, France who was not involved in the trial.

However, he notes that DBS typically offers much more benefit to patients with Parkinson's disease. And, he adds, unlike gene therapy, DBS can be tuned up or down depending on a patient's current condition.

Despite this, Palfi remains enthusiastic that gene therapy could provide another tool with which to manage Parkinson's disease. He is involved in an early-stage safety trial for delivering genes involved in making dopamine to the brains of patients with Parkinson's disease. Palfi says that, so far, nine people have received the treatment.

Other scientists are testing gene therapies that prevent neuron from dying in patients with Parkinson's disease.

Marc Panoff, chief financial officer at Neurologix, says that the company will seek permission from the US Food and Drug Administration later this year to conduct a larger clinical trial.

Source: http://www.nature.com/news/2011/110317/full/news.2011.167.html

China, Australia to collaborate on genetic research

Australian and Chinese researchers have agreed to collaborate on a new genetic research project to find a link between genes and diseases.

They will use the information gathered to develop new medicines that can help people according to their specific genetic make-up.

Liver disease and obesity are just two conditions that can benefit from a better understanding of human genes and personally-targeted drug treatments.

The director of the China-Australia Centre for Phenomics Research, Dr Ed Bertram, has told Radio Australia's Connect Asia program, the project will be fast-tracking research by many years.

He says they are teaming up with the Beijing Genomics Institute, a world leader in genome sequencing technology for more than 10 years.

"One of the key projects that we will be working with is to build a large-scale library of some 10,000 unique fully-sequenced genetic mice with mutations of every gene in the genome," he said.

"Researchers can then access to study or validate genes from the human genome sequences for finding cause and mutations that are involved in disease."

Dr Bertram says the information will allow them to develop new therapies and drugs, as well as look at current drugs and treatments and their suitability for patients.

The China-Australia Centre, located at the Australian National University in Canberra, was one of four joint research centres set up with the support of the Australian and Chinese governments in 2008.

Dr Bertram says the new initiative is the start of a long-term partnership.

"It's really the latest technology development that will allow us to rapidly increase that output," he said.

"And we've found working with China to be a very good collaboration, particularly in this area."

 

source: Radio Australia News

High Cholesterol protects against Infections

A very good read..Many researchers have suggested that the blood lipids play a key role in the immune defence system. There is also a growing understanding that an inflammatory response of the arterial intima to injury is a crucial step in the genesis of atherosclerosis. and that infections may be one type of such injury.22 These two concepts are difficult to harmonize with the low-density-lipoprotein (LDL) receptor hypothesis, according to which high LDL cholesterol is the most important cause of atherosclerosis. However, the many observations that conflict with the LDL receptor hypothesis, may be explained by the idea that high serum cholesterol and/or high LDL is protective against infection and atherosclerosis.

Read the whole article here

Old Genes Can Learn New Tricks, Horned Beetles Show

A popular view among evolutionary biologists that fundamental genes do not acquire new functions has been challenged by a new study in the Proceedings of the National Academy of Sciences.

Indiana University Bloomington biologist Armin Moczek and research associate Debra Rose report that two ancient genes were "co-opted" to help build a new trait in beetles -- the fancy antlers that give horned beetles their name. The genes, Distal-less and homothorax, touch most aspects of insect larval development, and have therefore been considered off-limits to the evolution of new traits. In the two horned beetle species Moczek and Rose studied, the genetic sequences of Distal-less and homothorax were hardly different, suggesting the two genes have retained their unique identities because of selective pressures not to change. What changed was not the genes themselves, but when and where they are turned on.

"Evolutionary biologists have a good idea of what it takes to change the shape of a wing, the length of a leg, or the anatomy of an eye," Moczek said. "What we have struggled with, though, is how these traits originate in the first place. How do you evolve that first wing, limb or photoreceptor from a flightless, limbless and blind ancestor?"

To investigate these questions, Moczek and Rose examined three development genes that are so old, all insects have them: Distal-less, homothorax and a third, dachshund. The genes were first characterized in fruit flies, and are categorized as "upstream" regulatory genes because they influence a wide variety of genetic processes in insect cells, such as the development of legs, antennae and wings. Moczek said that in horned beetles, each of the three genes is likely to have hundreds to thousands of downstream targets.

A tenuous consensus among evolutionary biologists was that such genes -- upon which so many different and important processes depend -- could not be easily modified, because any modification would affect countless aspects of the insect's development, any one of which could be bad for the individual insect, reducing its fitness relative to its peers.

Moczek and Rose's PNAS paper confirms one aspect of this idea. All three genes were sequenced and found to be highly conserved, or unchanged, not only among the individuals of each beetle species they examined, but also between the two species, Onthophagus taurus (Italy) and Onthophagus binodis (South Africa), whose lineages diverged about 24 million years ago. But that isn't the whole story.

To understand the effects of the three genes on horned beetle development, Moczek and Rose employed a new and promising technique, RNA interference, which disables the action of specific genes without compromising other genetic processes. Humans are only mimicking nature here; RNA interference is also a natural method of gene regulation in eukaryotes.

Moczek and Rose divided beetle larvae of both species into three treatment groups: no injection, buffer injection with nonsense RNA and buffer injection with RNA interference transcripts designed to disrupt one of three crucial developmental genes.

Moczek and Rose learned that two of the three genes, Distal-less and homothorax, are used by both O. taurus and O. binodis in the development of beetle horns. While Distal-less was found to affect both the development of thorax horns (which form just behind the head) and head horns, homothorax was only found to influence thorax horn development. The gene dachshund appears to have no effect whatsoever on horn development in either species.

"The evolution of novel features does not require the evolution of novel genes," Moczek said. "A lot of innovation can grow from within the organism's genetic toolbox."

More importantly, Moczek and Rose learned all developmental genes are candidates for such recruitment, not just the genes whose development functions are considered non-essential or limited in their effects.

Moczek also says the PNAS paper may compel evolutionary biologists to revisit pleiotropy, the foundational concept of one gene influencing many traits.

"It may be that our understanding of pleiotropy is too simplistic," Moczek said. "Now that we know fundamental development genes can acquire new and diverse functions with relative ease, pleiotropy may not be nearly as constraining as we have thought."

U.S. company finds "safer" way to make stem-like cells

U.S. researchers said on Thursday they had come up with the safest way yet to make stem-like cells using a patient's ordinary skin cells, this time by using pure human proteins. The team at Harvard University and Massachusetts-based Advanced Cell Technology Inc said their technique involves soaking cells in human proteins that turn back the clock biologically, making the cells behave like powerful embryonic stem cells.

Dr. Robert Lanza of Advanced Cell sees almost immediate commercial applications.

"After a few more flight tests -- in order to assure everything is working properly -- it should be ready for commercial use," Lanza said by e-mail.

He said the company would seek Food and Drug Administration permission to test the cells in people by next year -- a process unlikely to be quick, especially with a brand-new technology such as this one.

Stem cells are the body's master cells, giving rise to all the tissues, organs and blood. Embryonic stem cells are considered the most powerful kind, as each one is pluripotent, with the potential to morph into any type of tissue.

Doctors hope to someday use them to transform medicine, for instance, by regenerating the cells destroyed in type 1 diabetes or regrowing eye cells to reverse blindness.

But embryonic cells require the use of an embryo or cloning technology, and several countries, including the United States, limit funding for such experiments.

Several teams of scientists have homed in on four genes that can turn back the clock in ordinary cells, making them look and act like embryonic stem cells. These so-called induced pluripotent stem cells, or iPS cells, could in theory be made using a patient's own skin, allowing grow-your-own transplants with no risk of rejection.

DIFFICULT WORK

Getting these genes into the cells is not easy, however.

The first attempts used retroviruses, which integrate their own genetic material into the cells they infect. Others used loops of genetic material called plasmids or other genetically engineered molecules to reformat the cells.

And another team used the proteins made by the four genes and valproic acid to reprogram cells, but Lanza said these methods all have drawbacks.

His team, working with Kwang-Soo Kim of the Harvard Stem Cell Institute and a team at CHA Stem Cell Institute in South Korea used a peptide, a protein fragment, to drag the human proteins into the cells.

"These have been around for a long time," Lanza said. "The AIDS virus uses the peptide to get into the cells it infects," he said.

Using cells from the foreskins of newborn boys -- a common laboratory technique -- they showed they could transform the cells into iPS cells. They regrew them into a variety of mature new cell types, they reported in the journal Cell Stem Cell.

"This method eliminates the risks associated with genetic and chemical manipulation, and provides for the first time a potentially safe source of iPS cells for translation into the clinic," Lanza said.

"This is the ultimate stem cell solution -- you just add some proteins to a few skin cells and voila! Patient-specific stem cells!"

One question that is not clear is who owns the technology. Lanza said many groups have tried to patent the various steps in the process and it is not yet clear whose patents will prevail.

New Cellular Targets For HIV Drug Development

Focusing HIV drug development on immune cells called macrophages instead of traditionally targeted T cells could bring us closer to eradicating the disease, according to new research from University of Florida and five other institutions.

In the largest study of its kind, researchers found that in diseased cells — such as cancer cells — that are also infected with HIV, almost all the virus was packed into macrophages, whose job is to "eat" invading disease agents.

What's more, up to half of those macrophages were hybrids, formed when pieces of genetic material from several parent HIV viruses combined to form new strains.

Such "recombination" is responsible for formation of mutants that easily elude immune system surveillance and escape from anti-HIV drugs.

"Macrophages are these little factories producing new hybrid particles of the virus, making the virus probably even more aggressive over time," said study co-author Marco Salemi, Ph.D., an assistant professor in the department of pathology, immunology and laboratory medicine at the UF College of Medicine. "If we want to eradicate HIV we need to find a way to actually target the virus specifically infecting the macrophages."

At least 1.1 million people in the United States and 33 million in the world are living with HIV/AIDS, according to the Kaiser Family Foundation.

The researchers set out to see if HIV populations that infect abnormal tissues are different from those that infect normal ones, and whether particular strains are associated with certain types of illness.

They tackled the question using frozen post-autopsy tissue samples, pathology results and advanced computational techniques. They analyzed 780 HIV sequences from 53 normal and abnormal tissues from seven patients who had died between 1995 and 2003 from various AIDS-related conditions, including HIV-associated dementia, non-Hodgkin's lymphoma and generalized infections throughout the body. Four patients had been treated with highly active antiretroviral therapy, called HAART, at or near the time of death.

The researchers compared brain and lymphoma tissues, which had heavy concentrations of macrophages, with lymphoid tissues — such as from the spleen and lymph nodes— that had a mix of HIV-infected macrophages and T cells.

The analyses revealed great diversity in the HIV strains present, with different tissues having hybrid viruses made up of slightly different sets of genes. A high frequency of such recombinant viruses was also found in tissues generally associated with disease processes, such as the meninges, spleen and lymph nodes.

The researchers concluded that HIV-infected macrophages might be implicated in tumor-producing mechanisms.

The higher frequency of recombinant virus in diseased tissues likely is because macrophages multiply as a result of an inflammatory response, the researchers said.

"The study points to macrophages as a site of recombination in active disease," said neurobiologist Kenneth C. Williams, Ph.D., a Boston College associate professor and AIDS expert who was not involved in the study. "So people can say this is one spot where these viruses come from."

T cells — the so-called conductors of the immune system orchestra, whose decline is the hallmark of HIV disease — are an obvious target for HIV drug development because they die soon after infection, and are readily sampled from the blood and cultured. But although current drugs are effective at blocking infection of new cells and lowering viral loads to barely detectable levels, they never reduce the viral level in an infected person to zero.

"Where is it coming from?" said Michael S. McGrath, the University of California, San Francisco, professor who led the research team. "We believe it's coming from these macrophages."

Macrophages, like T cells, can be infected multiple times by HIV. But unlike T cells, when they get infected, they don't die within days, but live for several months, all the while being re-infected with multiple viruses of different genetic makeup. That situation is ripe for the emergence of hybrids.

"Most people who look at viral sequences assume that evolution of the virus is linear. In the real world that doesn't happen — large parts of the virus are swapped in and out. This group has shown that in this model," Williams said. "It sort of overturns the old way of trying to match virus sequence with pathology."

McGrath's group is now developing macrophage-targeting drugs that, through a grant from the National Institute of Mental Health, should be in human clinical trials in a few years.

"This is one of the last frontiers — killing off what we believe is a so far untouched reservoir," he said.

The work was published recently in the journal PLoS One.

Gene-laden Bubbles Grow New Blood Vessels

Progress in human gene therapy -- the insertion of therapeutic DNA into tissues and cells in the human body -- has been slower than expected since the first clinical trials in 1990. One of the biggest challenges for this technology is finding ways to safely and effectively deliver genes only to the specific parts of the body that they are meant to treat.

Cardiologist Jonathan Lindner of Oregon Health and Science University will discuss his latest experiments in gene therapy, which use microscopic bubbles chemically modified to stick to the cells that line blood vessels.

This technique, ultrasound-mediated gene delivery (UMGD), exploits the properties of contrast agents, microparticles that are normally injected into the body to improve the quality of ultrasound images. In UMGD, the tiny particles are microbubbles composed of pockets of gas encapsulated by thin membranes that are coated with DNA before injection. A targeted pulse of ultrasound energy "rings" the bubbles like a bell, popping them in a specific location and releasing the DNA into the surrounding tissue.

To improve the specificity of this targeting, Lindner grafts long arm-like molecules to the outside of the bubbles. These arms, which do not interfere with the DNA attached to surface, are designed to recognize and bind to molecules on the outside of specific cells in the body, allowing the bubbles to attach to a tissue before being popped. In theory, this should improve both the specificity and efficiency of the gene therapy.

Lindner created an arm designed to attach to endothelial cells lining blood vessels. He will present data evaluating the behavior of these "targeted" bubbles in living tissue. The ability to stick these gene-laden microbubbles to the lining of blood vessels increased the amount of gene transfection. This strategy may be particularly important for delivering therapeutic DNA to the walls of blood vessels. For example, Dr. Lindner and collaborators have successfully stimulated the growth of new blood vessels using UMGD with microbubbles carrying a gene for vascular endothelial growth factor. This therapeutic use could be important for treating ischemia in patients who have had a heart attack, peripheral artery disease, or stroke.

The team is also investigating using the bubbles to transport small doses of drugs. "If you're trying to deliver a nasty drug to part of the body, this may be a way to improve safety," says Lindner.

The talk "Targeted microbubble technology and ultrasound-mediated gene delivery" by Jonathan Lindner will be presented at the 157th  Acoustical Society of America Meeting to be held May 18-22 in Portland, Ore.

Fish Oil Protects Against Diseases Like Parkinson's

Dr. Nicolas Bazan, Director of the Neuroscience Center of Excellence, Boyd Professor, and Ernest C. and Yvette C. Villere Chair of Retinal Degenerative Diseases Research at LSU Health Sciences Center New Orleans, will present new research findings showing that an omega three fatty acid in the diet protects brain cells by preventing the misfolding of a protein resulting from a gene mutation in neurodegenerative diseases like Parkinson's and Huntington's.

He will present these findings for the first time on April 19, 2009 at the Ernest N. Morial Convention Center, Nouvelle C Room, at the American Society for Nutrition, Experimental Biology 2009 Annual Meeting.

With funding from the National Eye Institute of the National Institutes of Health, Dr. Bazan and his colleagues developed a cell model with a mutation of the Ataxin-1 gene. The defective Ataxin-1 gene induces the misfolding of the protein produced by the gene. These misshapened proteins cannot be properly processed by the cell machinery, resulting in tangled clumps of toxic protein that eventually kill the cell. Spinocerebellar Ataxia, a disabling disorder that affects speech, eye movement, and hand coordination at early ages of life, is one disorder resulting from the Ataxin-1 misfolding defect. The research team led by Dr. Bazan found that the omega three fatty acid, docosahexaenoic acid (DHA), protects cells from this defect.

Dr. Bazan's laboratory discovered earlier that neuroprotectin D1 (NPD1), a naturally-occurring molecule in the human brain that is derived from DHA also promotes brain cell survival. In this system NPD1 is capable of rescue the dying cells with the pathological type of Ataxin-1, keeping their integrity intact.

"These experiments provide proof of principle that neuroprotectin D1 can be applied therapeutically to combat various neurodegenerative diseases," says Dr. Bazan. "Furthermore, this study provides the basis of new therapeutic approaches to manipulate retinal pigment epithelial cells to be used as a source of NPD1 to treat patients with disorders characterized by this mutation like Parkinson's, Retinitis Pigmentosa and some forms of Alzheimer's Disease."

Earliest Evidence Of Domesticated Maize Discovered: Dates Back 8,700 Years

This is so fascinating. According to Ranere, recent studies have confirmed that maize derived from teosinte, a large wild grass that has five species growing in Mexico, Guatemala and Nicaragua. The teosinte species that is closest to maize is Balsas teosinte, which is native to Mexico's Central Balsas River Valley.

"We went to the area where the closest relative to maize grows, looked for the earliest maize and found it," said Ranere. "That wasn't surprising since molecular biologists had determined that Balsas teosinte was the ancestral species to maize. So it made sense that this was where we would find the earliest domestication of maize."

The study began with Piperno, a Temple University anthropology alumna, finding evidence in the form of pollen and charcoal in lake sediments that forests were being cut down and burned in the Central Balsas River Valley to create agricultural plots by 7000 years ago. She also found maize and squash phytoliths -- rigid microscopic bodies found in many plants -- in lakeside sediments.

Ranere, an archaeologist, joined in the study to find rock shelters or caves where people lived in that region thousands of years ago. His team carried out excavations in four of the 15 caves and rock shelters visited in the region, but only one of them yielded evidence for the early domestication of maize and squash.

Ranere excavated the site and recovered numerous grinding tools. Radiocarbon dating showed that the tools dated back at least 8700 years. Although grinding tools were found beneath the 8700 year level, the researchers were not able to obtain a radiocarbon date for the earliest deposits. Previously, the earliest evidence for the cultivation of maize came from Ranere and Piperno's earlier research in Panama where maize starch and phytoliths dated back 7600 years.

Ranere said that maize starch, which is different from teosinte starch, was found in crevices of many of the tools that were unearthed.

"We found maize starch in almost every tool that we analyzed, all the way down to the bottom of our site excavations," Ranere said. "We also found phytoliths that comes from maize or corn cobs, and since teosinte doesn't have cobs, we knew we had something that had changed from its wild form."

Ranere said that their findings also supported the premise that maize was domesticated in a lowland seasonal forest context, as opposed to being domesticated in the arid highlands as many researchers had once believed.

"For a long time, I though it strange that researchers argued about the location and age of maize domestication yet never looked in the Central Balsas River Valley, the homeland for the wild ancestor," said Ranere. "Dolores was the first one to do it.'

In addition to Ranere and Piperno, other researchers in the study included Irene Holst of the Smithsonian Tropical Research Institute, Ruth Dickau of Temple, and Jose Iriarte of the University of Exeter. The study was funded by the National Science Foundation, National Geographic Society, Wenner-Gren Foundation, Smithsonian National Museum of Natural History, Smithsonian Tropical Research Institute and the Temple University College of Liberal Arts.

Glucose-To-Glycerol Conversion In Long-lived Yeast Provides Anti-aging Effects

Cell biologists have found a more filling substitute for caloric restriction in extending the life span of simple organisms. In a study published May 8 in the open-access journal PLoS Genetics, researchers from the University of Southern California Andrus Gerontology Center show that yeast cells maintained on a glycerol diet live twice as long as normal -- as long as yeast cells on a severe caloric-restriction diet. They are also more resistant to cell damage.

Many studies have shown that caloric restriction can extend the life span of a variety of laboratory animals. Caloric restriction is also known to cause major improvements in a number of markers for cardiovascular diseases in humans. This study is the first to propose that "dietary substitution" can replace "dietary restriction" in a living species.

"If you add glycerol, or restrict caloric intake, you obtain the same effect," said senior author Valter Longo. "It's as good as calorie restriction, yet cells can take it up and utilize it to generate energy or for the synthesis of cellular components."

Longo and colleagues Min Wei and Paola Fabrizio introduced a glycerol diet after discovering that genetically engineered long-lived yeast cells that survive up to 5-fold longer than normal have increased levels of the genes that produce glycerol. In fact, they convert virtually all the glucose and ethanol into glycerol. Notably, these cells have a reduced activity in the TOR1/SCH9 pathway, which is also believed to extend life span in organisms ranging from worms to mice.

When the researchers blocked the genes that produce glycerol, the cells lost most of their life span advantage. However, Longo and colleagues believe that the "glucose to glycerol" switch represents only a component of the protective systems required for the extended survival. The current study indicates that glycerol biosynthesis is an important process in the metabolic switch that allows this simple organism to activate its protective systems and live longer.

"This is a fundamental observation in a very simple system," Longo said, "that at least introduces the possibility that you don't have to be calorie-restricted to achieve some of the remarkable protective effects of the hypocaloric diet observed in many organisms, including humans. It may be sufficient to substitute the carbon source and possibly other macronutrients with nutrients that do not promote the "pro-aging" changes induced by sugars."

Funding for the study came from the American Federation for Aging Research and the National Institute on Aging (NIH).

Groundbreaking Study Reveals Intermediary Steps Of Genetic Encoding For The First Time

The scientists report that they were able to crystallize a very large complex of a macromolecular "machine" in the human cell and determine its structure or what it actually looks like, thereby zeroing in on the process of genetic encoding. Importantly, 15 to 20 percent of all human genetic disorders, including muscular dystrophy, are caused by defects in this genetic encoding process known as RNA splicing.

Using x-ray crystallography, the scientists for the first time were able to create a three-dimensional structure of an integral complex of the human spliceosome, which consists of specialized RNA and protein subunits. The spliceosome's job is to modify the message relayed from our genetic material—DNA—by clipping, or splicing, genetic bits in such a manner that they are acceptable for translation into protein. Importantly, the spliceosome also rearranges the genetic bits of the message in such a way that it can generate multiple and varied proteins which can and do have dramatic effects on human development, said lead author and Brandeis biochemist Daniel Pomeranz Krummel.

"The process of RNA splicing is vital to human cell development and survival," said Pomeranz Krummel. "In this process, the regions of our DNA encoding for protein are removed from non-encoding regions and brought together—quite often in alternative arrangements. Defects in this process can have disasterous repercussions in the form of genetic disorders," said Pomeranz Krummel, adding that neuronal development can be particularly affected when things go awry. Indeed, defects in this process have recently been implicated in various human neurological disorders, including epilepsy.

Specifically, this macromolecular machine clips, or splices, gene sequences transcribed as part of a precursor to the mRNA, removing them before the final mRNA product is translated into protein. The spliceosome must clip these sequences, known as introns, at the right place in the precursor mRNA.

"In human cells one gene can be made into a variety of proteins, so if the process just goes slightly wrong, the genetic alteration can lead to incredible disaster; yet on the other hand, this incredible complexity has led to our amazing evolutionary progress," said Pomeranz Krummel. "The human genome is not terribly different from the earthworm's with regards to its size, but the process of RNA splicing that occurs in our cells is different. The fundamental difference between us and the earthworm is that our cells have evolved to utilize this process of RNA splicing to generate a whole other dimension to the transmission of genetic information."

Pomeranz Krummel's lab will next focus on understanding how this complex interacts with other macromolecular machines in the human cell. The study was funded by the Medical Research Council (U.K.) and the Human Frontier Science Program.

Did you know?? Omega-3 Kills Cancer Cells

Docosahexanoic acid (DHA), an omega-3 fatty acid found in fish oils, has been shown to reduce the size of tumours and enhance the positive effects of the chemotherapy drug cisplatin, while limiting its harmful side effects. The rat experiments provide some support for the plethora of health benefits often ascribed to omega-3 acids.

DHA is an omega-3 fatty acid that is commonly found in cold-water fish oil, and some vegetable oils. It is a major component of brain gray matter and of the retina in most mammalian species and is considered essential for normal neurological and cellular developments. According to the authors, "While DHA has been tentatively linked with protection against cardiovascular, neurological and neoplastic diseases, there exists a paucity of research information, in particular regarding its interactions with existing chemotherapy drugs". The researchers found that, at the molecular level, DHA acts by reducing leukocytosis (white blood cell accumulation), systemic inflammation, and oxidative stress – all processes that have been linked with tumour growth.

El-Mowafy and his colleagues have called for greater deployment of omega-3 in the fight against cancer. They write, "Our results suggest a new, fruitful drug regimen in the management of solid tumors based on combining cisplatin, and possibly other chemotherapeutics, with DHA".

Human Genes Required For Hepatitis C Viral Replication Identified

Massachusetts General Hospital (MGH) researchers are investigating a new way to block reproduction of the hepatitis C virus (HCV) – targeting not the virus itself but the human genes the virus exploits in its life cycle. In the March 19 Cell Host & Microbe, they report finding nearly 100 genes that support the replication of HCV and show that blocking several of them can suppress viral replication in cultured cells.

"We identified a large number of genes that have not been previously known to be involved in hepatitis C replication," says Raymond Chung, MD, director of Hepatology in the MGH Gastrointestinal Unit, the study's senior author.

Lead author Andrew Tai, MD, PhD, also of the MGH Gastrointestinal Unit, adds, "We may be a few years away from developing therapies based on these findings, but this study is a proof of principle that targeting host factors is a viable therapeutic strategy."

Usually spread by blood-to-blood contact, HCV infection becomes chronic in 70 to 80 percent of patients, and long-term infection can lead to liver failure or liver cancer. Today HCV-related liver disease is the most common diagnosis underlying the need for liver transplantation. HCV infection is usually treated with a six- to eleven-month regimen combining peginterferon and the antiviral drug ribavirin, but treatment is not successful in many patients and has serious side effects some cannot tolerate. Other therapies targeting viral enzymes are being developed, but there is concern that HCV's ability to mutate rapidly would lead to the emergence of resistant strains, so strategies directed against factors in the infected host rather than the virus may offer a complementary approach.

These strategies are being explored in a number of diseases – including influenza, West Nile virus and HIV – and previous studies have scanned a limited number of human genes for host cofactors of HCV infection. For the current study the researchers examined whether blocking each of the approximately 21,000 predicted messenger RNA transcripts in the human genome with small interfering RNAs (siRNAs) had any effect on HCV replication. Chung notes that this approach does not rely on any prior assumptions about gene function and can thereby identify genes not previously suspected of involvement.

The siRNA scan found 96 genes that appear to have a role in viral replication, and the research team studied several of them in greater detail. One gene codes for an enzyme called PI4KA, which is believed to be involved in the formation of membrane structures within the cell that may be the site of HCV replication. Another group of genes contribute to formation of the COPI coat that covers several types of cellular vesicles and is known to have a role in the replication of poliovirus. The researchers also focused on the gene for hepcidin, a liver protein that regulates iron absorption, since iron levels in the blood and liver rise in chronic HCV infection. They found that blocking each of these genes also blocked HCV replication, as did drugs that inhibit PI4KA and COPI, although the tested agents might not be suitable for therapeutic use.

"Now we need to work to uncover the molecular mechanisms by which these genes support HCV replication to get a better idea of which would be advantageous therapeutic targets," explains Chung, an associate professor of Medicine at Harvard Medical School.

Additional co-authors of the Cell Host & Microbe paper are Yair Benita, PhD, Sun-Suk Kim, MD, and Ramnik Xavier, MB,ChB, MGH Gastrointestinal Unit; and Naoya Sakamoto, MD, PhD,Tokyo Medical and Dental University. The study was supported by grants from the National Institutes of Health, the Massachusetts Biomedical Research Corporation, the American Gastrointestinal Association and the American Liver Foundation.

Newly Identified Protein May Inhibit Hepatitis Virus

A newly identified family of proteins may inhibit replication of the
Hepatitis B (HBV) and C (HCV) viruses say researchers from California.
Their findings appear in the March 2005 issue of the Journal of
Virology.Hepatitis B (HBV) and C (HCV) are viruses that infect the liver, and in some cases can cause liver failure requiring a transplant for survival. The protein interferon, produced by animal cells when they are invaded by viruses, is released into the bloodstream or intercellular fluid to induce healthy cells to manufacture an enzyme that counters the infection. One class of interferons (alpha) is used to treat chronic infection with HBV and HCV. There is a vaccine available to prevent the spread of HBV but not HCV.

In the study, a new class of interferons, interferon lambda, was tested for its ability to inhibit HBV and HCV replication. Results showed 90% inhibition of HBV after twenty-four hours and 90-99% inhibition in HCV five days posttreatment.

“We have demonstrated here that replication of HBV and HCV is sensitive to the antiviral activities of interferon lambda,” say the researchers. “These results suggest the possibility that interferon lambda may be therapeutically useful in the treatment of chronic HBV or HCV infection.”

(M.D. Robek, B.S. Boyd, F.V. Chisari. 2005. Lambda interferon inhibits hepatitis B and C virus replication. Journal of Virology, 79. 6: 3851-3854.)

Mutated Gene In Zebrafish Sheds Light On Blindness In Humans

Described in a paper published in the Proceedings of the National Academy of Sciences (PNAS), the landmark study of retinal development in zebrafish larvae and the genetic switch it has identified should shed new light on the molecular mechanisms underlying that development and, consequently, provide needed insight on inherited retinal diseases in humans.

From FSU's Department of Biological Science and Program in Neuroscience, doctoral candidate Karen Alvarez-Delfin (first author of the PNAS paper), postdoctoral fellow Ann Morris (second author), and Associate Professor James M. Fadool are the first scientists to identify the crucial function of a previously known gene called "tbx2b." The researchers have named the newfound allele (a different form of a gene) "lor" -- for "lots-of-rods" -- because the mutation results in too many rods and fewer ultraviolet cones than in the normal eye.

"Our goal is to generate animal models of inherited diseases of the eye and retina to understand the progression of disease and find more effective treatments for blindness," said Fadool, faculty advisor to Alvarez-Delfin and principal investigator for Morris's ongoing research. "We are excited about the mutation that Karen has identified because it is one of the few mutations in this clinically critical pathway that is responsible for cells developing into one photoreceptor subtype rather than another."

"What is striking in this case is that the photoreceptor cell changes we observed in the retinas of zebrafish are opposite to the changes identified in Enhanced S-cone syndrome (ESCS), an inherited human retinal dystrophy in which the rods express genes usually only found in cones, eventually leading to blindness," Alvarez-Delfin said. "Equally surprising is that this study and others from our lab show that while alterations in photoreceptor development in the human and mouse eyes lead to retinal degeneration and blindness, they don't in zebrafish. Therefore, the work from our Florida State lab and with our collaborators at the University of Pennsylvania, Vanderbilt University and the University of Louisville should provide a model for better understanding the differences in outcomes between mammals and fish, and why the human mutation leads to degenerative disease."

Morris calls the zebrafish an ideal genetic model for studies of development and disease. The common aquarium species are vertebrates, like humans. Their retinal organization and cell types are similar to those in humans. Zebrafish mature rapidly, and lay many eggs. The embryos are transparent, and they develop externally, unlike mammals, which develop in utero.

"This lets us study developmental processes such as the formation of tissues and organs in living animals," she said.

"From a developmental biology perspective, our research will help us unravel the competing signals necessary for generating the different photoreceptor cell types in their appropriate numbers and arrangement," Morris said. "The highly specialized nature of rods and cones may make them particularly vulnerable to inherited diseases and environmental damage in humans. Understanding the genetic processes of photoreceptor development could lead to clinical treatments for the millions of people affected by photoreceptor cell dystrophies such as retinitis pigmentosa and macular degeneration."

The mosaic arrangement of photoreceptors in fish was first described more than 100 years ago, but the J. Fadool laboratory at Florida State was the first to successfully take advantage of the pattern to identify mutations affecting photoreceptor development and degeneration.

"Imagine a tile mosaic," Fadool said. "That is the kind of geometric pattern formed by the rod and cone photoreceptors in the zebrafish retina. This mosaic is similar to the pattern of a checkerboard but with four colors rather than two alternating in a square pattern. The red-, green-, blue-, and ultraviolet-sensitive cones are always arranged in a precise repeating pattern. Human retinas have a photoreceptor mosaic, too, but here the term is used loosely, because while the arrangement of the different photoreceptors is nonrandom, they don't form the geometric pattern observed in zebrafish.

"So how do we ask a fish if it has photoreceptor defects?" he asked.

Fadool explained that because the mosaic pattern of zebrafish photoreceptors is so precise, mutations causing subtle alterations are easier to uncover than in retinas with a "messier" arrangement.

"Just as we can easily recognize a checkerboard mistakenly manufactured with some of the squares changed from black to red or with all-black squares, by using fluorescent labeling and fluorescence microscopes we can see similar changes in the pattern of the zebrafish photoreceptor mosaic," he said. "Karen showed that within the mosaic of the lots-of-rod fish, the position on the checkerboard normally occupied by a UV cone is replaced with a rod. The identity of the mutated gene is then discovered using a combination of classical genetics and genomic resources."

Funding for the Fadool laboratory's zebrafish research comes in large part from a five-year grant totaling more than $1.7 million from the National Institutes of Health.

Rejoice Fatboys!! Fitness More Than Fatness Determines Your Health and Longevity

Did you know that fitness level is a strong predictor of longevity, especially for adults over age 60? While obesity receives much airtime as a public health problem, it seems that being thin is not the be-all and end-all of a healthy body.

Results of a 12-year study have indicated that fitness levels can be more important than your weight levels and can definitely influence whether or not you suffer from health problems and die earlier than those who are physically fit but not necessarily thin.

The 12-year study was conducted by Professor Steven Blair from the University of South Carolina in Columbia. Researchers looked at the relationship between body fat, fitness and longevity in 2,603 people over the age of 60.

At the start of the study, fitness levels were assessed using a treadmill stress test and body fat was calculated by various measures, including BMI, waist circumference and fat percentages. The volunteers had follow-up medical checks over the 12-year study period.

The overall results showed that fit adults who engage in cardiovascular exercise on a regular basis outlived the unfit, regardless of their level of obesity or waist size. There were 450 deaths during the study. Researchers found that those who died were older, had lower fitness levels and had more cardiovascular risk factors than survivors.

Death rates for those with higher fitness levels were less than half of the rates for those who were unfit and not surprisingly they were less likely to have risk factors for cardiovascular disease, such as hypertension, diabetes, or high cholesterol levels. The exception however was with those who were severely obese or with large amounts of abdominal fat.

The message from these study results is that there is great benefit to being physically active on a regular basis even if you are overweight. Exercise has a systematic effect on many levels - it strengthens the heart, the lungs and builds up the skeletal muscles. It also provides great benefit to the brain and the overall well-being of the person. It is important though to maintain a healthy body weight at the same time.

"Our data provides further evidence regarding the complex long-term relationship among fitness, body size and survival. It may be possible to reduce all-cause death rates among older adults, including those who are obese, by promoting regular physical activity, such as brisk walking for 30 minutes or more on most days of the week," said Dr. Xuemei Sui of the University of South Carolina.

Gene Therapy Demonstrates Benefit In Patients With Rheumatoid Arthritis

Researchers have reported the first clinical evidence that gene therapy reduces symptoms in patients with rheumatoid arthritis, an important milestone for this promising treatment which has endured a sometimes turbulent past.

Described in the February issue of the journal Human Gene Therapy the findings stem from a study of two patients with severe rheumatoid arthritis conducted in Germany and led by an investigator at Beth Israel Deaconess Medical Center (BIDMC).

Originally conceived as a means of treating genetic diseases, such as cystic fibrosis and hemophilia, gene therapy involves implanting a normal gene to compensate for a defective gene in the patient. The first clinical trial to test gene therapy was launched in 1990 for the treatment of a rare, genetic immunodeficiency disease.

"This study helps extend gene therapy research to nongenetic, nonlethal diseases," explains principal investigator Christopher Evans, PhD, Director of the Center for Advanced Orthopaedic Studies at BIDMC. "Rheumatoid arthritis [RA] is an extremely painful condition affecting multiple joints throughout the body. Arthritis is a good target for this treatment because the joint is a closed space into which we can inject genes," adds Evans, who is also the Maurice Muller Professor of Orthopaedic Surgery at Harvard Medical School.

A classic autoimmune disease, RA develops when, for unknown reasons, the body's immune system turns against itself, causing joints to become swollen and inflamed. If the disease is inadequately controlled, the tissues of the joint are eventually destroyed. Although anti-inflammatory agents and biologics can help to mitigate symptoms, there is no cure for the condition, estimated to affect more than 2 million individuals in the U.S. alone.

Evans has spent many years studying the molecules responsible for the breakdown of cartilage in patients with arthritis, identifying interleukin-1 as a good target. But, he adds, once he had this answer, another question was not far behind: How could he effectively reach the joints to block the actions of this protein?

Gene therapy provided the answer.

By implanting a gene in the affected joint, he was able to stimulate production of a human interleukin-1 receptor antagonist protein, which serves to block actions of the interleukin-1 protein.

"The idea is that by remaining in place, the new gene can continuously block the action of the interleukin-1 within the joints," says Evans. "In essence, the gene becomes its own little factory, continuously working to alleviate pain and swelling."

In 2005, in a study published in the Proceedings of the National Academy of Sciences (PNAS), Evans and colleagues demonstrated that the IL-1Ra gene could be safely transferred to human joints in patients with RA. In this new paper, the authors aimed to prove that the therapy was not only safe, but that it was of therapeutic benefit.

Two study subjects were recruited. (The number reduced from six study subjects following severe adverse events in an unrelated gene therapy trial taking place elsewhere, according to Evans.) Both subjects were postmenopausal females under the age of 75 with a diagnosis of advanced rheumatoid arthritis. After tissue was removed from the subjects' knuckle joints, a harmless retrovirus was inserted into the tissue cells, in order to serve as a "vector" to transport the gene into the patients' joints. After being placed in culture to grow and replicate, the cells were injected back into the afflicted joints.

After four weeks, patients reported reduced pain and swelling, according to Evans. "In one of the two subjects, these effects were dramatic, and the gene-treated joints remained pain-free even though other joints experience flares." Subsequent laboratory tests showed that tissues removed from the subject's joint tissue synthesized lower amounts of disease-related proteins, confirming that the reduction in pain and swelling resulted from the actions of the implanted gene.

"Existing treatments for rheumatoid arthritis are costly and need to be administered regularly," says Evans, adding that in addition to risk of side effects, not all patients respond well. "This paper provides us with the first real evidence that painful symptoms can indeed be lessened through gene therapy."

Ongoing work will focus on the use of gene therapy for the treatment of osteoarthritis, as well as rheumatoid arthritis.

This study was funded, in part, by grants from the National Institutes of Health and Orthogen, a German biotechnology company.

Study coauthors include Peter Wehling, Julio Reinecke, Axel Baltzer, Marcus Granrath, Klaus Schulitz, Carl Schultz, and Rudiger Krauspe of the University of Dusseldorf School of Medicine, Germany; Theresa Whiteside, Elaine Elder and Paul Robbins of the University of Pittsburgh School of Medicine; and Steven Ghivizzani of the University of Florida College of Medicine.

Is There A Relationship Between Sleep-wake Rhythm And Diabetes?

An international research team with German participation including Helmholtz Zentrum München, among other institutions, has succeeded in identifying a new gene variant which is associated with elevated fasting glucose levels and a high risk for type 2 diabetes. The gene mediates insulin secretion indirectly via the release of melatonin, which implicates a previously unknown relationship between the sleep-wake rhythm and the fasting glucose level. The finding could open up new possibilities of treatment which go far beyond the primarily symptomatic therapy approaches to diabetes that have been practised until now.

Diabetes mellitus and diabetes-associated late complications are among the most frequent chronic diseases and causes of death worldwide. In Germany there are approximately six million people with type 2 diabetes who are aware that they have the disease. In addition, there is a relatively high estimated number of undiagnosed diabetics. Besides lifestyle factors such as overweight and lack of exercise, genetic factors play an important role in the pathogenesis of this disease.

The international MAGIC Consortium (MAGIC = Meta-Analyses of Glucose and Insulin-related traits Consortium) combined the data from 13 case-control studies with over 18,000 diabetic and 64,000 non-diabetic study participants and was able to identify a variant of the MTNR1B gene which is associated with both elevated fasting glucose levels as well an elevated risk for type 2 diabetes. The goal of the MAGIC Consortium is to identify gene variants which regulate the fasting glucose levels in healthy individuals.

Germany is represented within the framework of the KORA studies by scientists of the Helmholtz Zentrum München (Assistant Professor Thomas Illig; Director of the KORA studies: Professor H.-Erich Wichmann) and the German Diabetes Center in Düsseldorf (Dr. Wolfgang Rathmann, Dr. Christian Herder; Direktor: Professor Michael Roden).

The MTNR1B gene is expressed in insulin-producing islet cells, among other cells, and encodes one of the two known melatonin receptors. It is assumed that this receptor inhibits the release of insulin via the neural hormone melatonin. The melatonin level in the body is high at night and declines in daylight, whereas the insulin level is higher during the day than in the night. Taken together, these new data implicate an association between the sleep-wake rhythm, the so-called circadian rhythm, and fasting glucose levels, which was not known previously.

Until now an efficient strategy for prevention and for therapies to treat the cause of the disease has been missing in diabetes research. The Helmholtz Zentrum München is working intensively on new approaches in the study and treatment of diabetes. Further studies will show which role melatonin plays in the regulation of insulin secretion, fasting glucose levels and the development of diabetes and whether this finding will lead to new treatment options.

Target That Could Ease Spinal Muscular Atrophy Symptoms Discovered

There is no cure for spinal muscular atrophy (SMA), a genetic disorder that causes the weakening of muscles and is the leading genetic cause of infant death, but University of Missouri researchers have discovered a new therapeutic target that improves deteriorating skeletal muscle tissue caused by SMA. The new therapy enhanced muscle strength, improved gross motor skills and increased the lifespan in a SMA model.

“This therapy does not directly target the disease-causing gene; instead it targets the pathways that affect muscle maintenance and growth,” said Chris Lorson, investigator in the Christopher S. Bond Life Sciences Center and associate professor of veterinary pathobiology in the MU College of Veterinary Medicine. “We administered a particular protein, follistatin, to SMA mouse models to determine if enhanced muscle mass impacts the symptoms of SMA. After treatment, the mice had increased muscle mass, gross motor function improvement and an increase in average life span of 30 percent.”

 With the therapy, MU researchers inhibited myostatin, a protein that limits muscle tissue growth. Myostatin activity can be reduced significantly by enabling several proteins that bind to myostatin, including follistatin. When myostatin is inhibited, muscle mass and strength increase.

SMA is caused by the loss of survival motor neuron-1(SMN1). Humans have a nearly identical copy gene called SMN2. Because of a single molecular difference, SMN2 alone cannot compensate for the loss of SMN1.

“While most work in the SMA field has logically focused on targeting the SMN2 gene, the results of this study suggest that skeletal muscle is a viable therapeutic target that may reduce the severity of some SMA symptoms,” said Lorson, who also is the scientific director for FightSMA, a private spinal muscular atrophy research foundation in Richmond, Va. “Because follistatin does not alter the expression level of SMN protein, the most effective treatment would combine strategies that directly address the genetic defect in SMA as well as SMN-independent strategies that enhance skeletal muscle.”

In Jan 2009, Lorson was awarded a $370,000 grant from the Muscular Dystrophy Association to continue his research on the role of muscle in SMA.