Playing true to form, Google cofounder Sergey Brin is launching an ambitious, expensive effort using unorthodox tactics, but this time he’s taking on Parkinson’s research. In cooperation with the personal genetics testing company 23andMe, which was cofounded by Brin’s wife, Anne Wojcicki, Brin is hoping to get 10,000 Parkinson’s patients to fill out online questionnaires and get their genomes scanned. To encourage participation, 23andMe will provide the DNA scan for $25, a fraction of the normal $399 price. Brin, who says he has an elevated risk of Parkinson’s, will contribute the bulk of the money for the study, although he declined to disclose the total costs.
Wojcicki says that getting full genetic information for so many patients could reveal genetic patterns to the disease, which has already been linked to a handful of genes. “We want to try and find out if there are other genetic variations that are associated with Parkinson’s or with rapid progression or slow progression,” said Wojcicki, in a telephone interview yesterday. “Also, why some people respond well to therapy, some people don’t, and some develop resistance faster” [Bloomberg].
(more…)
The controversy surrounding stem cell research might soon be moot, with new research showing that ordinary skin cells can be transformed into an equivalent of embryonic stem cells, which have been the focus of research because of their ability to become any kind of cell in the human body. This is known as a pluripotent state, and the new research, published in two articles in Nature, marks the first time that scientists have turned skin cells into induced pluripotent stem cells or iPS cells—which look and act like embryonic stem cells—without having to use viruses in the process [Reuters].
Scientists have been able to make stem cells from adult cells for more than a year, but relied on the injection of a virus to trigger the transformation of the cell into the embryonic state. These cells could not be used on patients, however, because of the risk they presented of developing cancer. Now, researchers in Britain and Canada have produced the cells by using strands of genetic material, instead of potentially dangerous genetically engineered viruses, to coax skin cells into a state that appears biologically identical to embryonic stem cells [Washington Post].
(more…)
A new study shows that teenage boy developed cancerous tumors because of the stem cell therapy he received years ago for a rare genetic condition. The boy, now 17, suffered from ataxia telangiectasia, or AT, a neurodegenerative disease that interferes with the part of the brain that controls movement and speech. AT patients do not usually live past their teens or 20s, and the Israeli boy, whose identity was not publicly revealed, was taken to Russia for experimental treatment. The first neural stem cells, taken from fetuses, were first injected into his brain and spinal cord when he was nine, and he received further injections at ages 10 and 12.
His condition deteriorated and he was using a wheelchair by age 13, when he also began to complain of headaches. Tests showed two growths, one pushing on his brain stem and the other on his spinal cord. The tumors were removed in 2006 and his health has since remained stable. But scientists at Tel Aviv University who wanted to determine the origin of the cancer have been in the lab ever since, and their findings have just been published in PLoS Medicine. The team found that the tumor could not have arisen from the boy, because he [has two disease-causing versions of the gene] that causes AT, while the DNA from the tumor cells carried only the normal version [The Scientist].
(more…)
A cure for the common cold may eventually be within reach, now that scientists have sequenced the genetic code of 99 strains of the common cold virus.
The research team, whose findings are published in Science, found that the strains are organized in about 15 family groups, each with its own ancestral path, which may explain why no one anti-viral drug works against all of them [Medical News Today]. By mapping a family tree of the common cold virus, or human rhinovirus, the researchers say they can identify the similarities and differences among all the strains. That family tree shows that some regions of the rhinovirus genome are changing all the time but that others never change. The … unchanging regions … are therefore ideal targets for drugs because, in principle, any of the 99 strains would succumb to the same drug [The New York Times].
The study also found something not thought possible in that type of virus: they recombine to form new strains…. which may account for the speed with which new strains emerge within one season [Medical News Today].
(more…)
For the first time, scientists have derived and cultured embryonic stem (ES) cells from rats, paving the way for genetically engineered rats that would more accurately model some human diseases than the currently available genetically engineered mice. Two collaborating teams developed a new approach to derive the ES cells, using a new cocktail of molecules to protect their precious pluripotency, the ability to differentiate into any type of cell. “This is a major development in stem cell research because we know that rats are much more closely related to humans than mice in many aspects of biology. The research direction of many labs around the world will change because of the availability of rat ES cells,” says Qilong Ying [Xinhua], who led one of the teams.
ES cells from mice have been available since 1981, and different researchers have created hundreds of different strains of “knock-out” mice—ones raised from ES cells in which certain genes are silenced to make apparent the genes’ functions. With mice, ES cells were grown with a mixture of growth signals to make them divide without differentiating. But transferring the same technique to rats and other mammals proved surprisingly difficult. To the great frustration of researchers, stem cells isolated from rat embryos and cultured with growth signals would quickly lose their pluripotency. The new strategy, reported in two studies in Cell [subscription required], involves growing the ES cells in a mixture of three key molecules that block the signals that normally induce differentiation. “Our discovery was that if you want to maintain cells in the undifferentiated state, you must block signals, not activate them,” says Ying… By repressing differentiation, the researchers could hold the cells in what they call a “ground state,” a blank slate ready to turn into any tissue in the body [Science News].
(more…)
In the western world, marriage between first cousins is labeled incest or inbreeding, and in the United States the practice is banned or restricted in 31 states. But a new essay argues that such laws are based on an outdated notion of the genetic risks involved in cousins marrying and reproducing. [T]hose laws “seem ill-advised” and “should be repealed,” a geneticist and medical historian write…. “Neither the scientific nor social assumptions that informed them are any longer defensible” [Scientific American].
First cousins share about an eighth of their genes, and are therefore more likely to receive two copies of some recessive gene that poses health problems. Scientists had assumed that the children of first cousins would therefore be more likely to be born with birth defects. But coauthor Hamish Spencer writes that the risk of congenital defects is about 2 per cent higher than average for babies born to first-cousin marriages – with the infant mortality about 4.4 per cent higher – which is on a par with the risk to babies born to women over 40. “Women over the age of 40 have a similar risk of having children with birth defects and no one is suggesting they should be prevented from reproducing,” said Professor Spencer [The Independent].
(more…)
A hormone produced in the gut appears to limit bone formation, scientists report in Cell [subscription required]. The hormone, serotonin, is the same one produced by the brain to regulate mood, learning, and sleep, but the new study finds that serotonin produced by the gut has an entirely separate function. Mice engineered to produce extra serotonin formed weak bones, while mice engineered to produce less serotonin developed extra-strong bones. The research, though still basic, suggests new avenues of osteoporosis research in humans. “It’s what you’d call a landmark study,” Bjorn Olsen [a Harvard cell biologist who was not involved with the study] says. “It opens new doors” [Science News].
Although serotonin produced by the gut makes up 95 percent of the body’s serotonin, its function had not been well understood. The connection between serotonin and bone formation revealed itself through two types of rare human diseases, both involving the gene Lrp5. People with one mutation produced less Lrp5 protein, developing fragile bones and blindness, while people with another mutation produced extra Lrp5 protein, developing unusually dense bones and resistance to osteoporosis. However, when the authors of the new study looked into the gene further, they were surprised to find that it acted not in bone cells but in cells of the gut. “We, as bone [researchers], thought of the skeleton as functioning independent of everything else,” said [Cliff Rosen, a bone biologist]. This group “asked the question, ‘could there be other regulators outside the skeleton that are regulating bone?’ and found the answer to be ‘yes.’” [The Scientist].
(more…)
Injury to nerve cells in the brain and spinal cord, once considered permanent, may be reversible after all. A pair of new studies demonstrate how to override two biological mechanisms that prevent damaged cells of the central nervous system from regrowing. The first obstacle are genes that prevent nerve growth and the second are chemical signals that repress nerve growth.
In the first study, published in Science [subscription required], Harvard researchers identified a gene, PETN, that inhibits the major growth pathway in nerve cells. They created genetically modified “knock-out” mice that lacked the gene. Normally, axons in the optic nerve of adult mice do not regenerate when crushed—and worse yet, about 80% of the neurons with severed axons die. But in mice lacking PTEN, 50% of neurons survived and about 10% of axons in the optic nerve regrew—as far as 4 millimeters in 28 days. “To have any manipulation that can make these axons grow from where they were severed near the retina all the way down the optic nerve is just amazing,” [ScienceNOW Daily News] commented neurobiologist Ben Barres.
(more…)
Ten intrepid genetic explorers have volunteered to have their genetic information posted on the Internet for anyone’s perusal, along with photographs, their disease histories, allergies, medications, ethnic backgrounds and a trove of other traits, called phenotypes, from food preferences to television viewing habits [The New York Times]. The 10 volunteers are the first participants in the Personal Genomics Project, an endeavor run by Harvard Medical School that hopes to offer free genetic testing to 100,000 people in exchange for their privacy.
The project aims to advance genome research by tapping volunteers who have a Facebook-mentality sense of privacy–minimal–and enough excitement about genomic science that they are willing to lay out their genetic and medical information so any researcher can sift through it for links between genes and traits. “There’s a hope that by making these data public, you can harness crowd-sourcing power in the same way that Wikipedia and YouTube and Google and Linux all emerged from cooperative, distributed efforts” [Boston Globe], said Harvard psychology professor Steven Pinker, who is one of the 10 pioneers.
(more…)
In a counterintuitive new study, researchers have found that obese women get less pleasure from drinking a chocolate milkshake than average-weight women, and suggest that obese women are therefore more likely to overeat in an attempt to get that high. Researchers used a fMRI brain scanner to record women’s levels of the pleasure-providing brain chemical dopamine while they were sipping milkshakes, and found that obese women had a muted pleasure response.
They also studied a dopamine-regulating gene variant that has previously been linked to obesity, and showed that women with this variant had the lowest dopamine levels and were also very likely to gain weight over the ensuing year. Dopamine expert Nora Volkow says this furthers the research on the genetic component of obesity: “It takes the gene associated with greater vulnerability for obesity and asks the question why. What is it doing to the way the brain is functioning that would make a person more vulnerable to compulsively eat food and become obese?” [AP]
(more…)
Two separate groups of researchers have developed a non-invasive test for Down syndrome, using only a blood sample from the pregnant woman to examine the fetus’ DNA. While the genetic tests are still in clinical trials, experts are hailing the achievement as significant because current prenatal tests like amniocentesis require inserting a needle in the uterus, and carry a risk of miscarriage.
A biotechnology company called Sequenom says it will begin selling its test next June, while researchers from Stanford, who just published their results in the Proceedings of the National Academy of Sciences, are still planning a large-scale clinical trial. Some experts say that the results are somewhat preliminary, and should be viewed cautiously: The Stanford test has been tried on only 18 blood samples. Sequenom has tried its test on only about 400 samples and has not yet published its results in peer-reviewed journals. Still, both tests have perfect records so far: no false negatives or false positives. “This is quite simply a major step forward, if it works at all like we expect it might,” [says Down Syndrome expert] Jacob A. Canick [The New York Times].
(more…)
A biotechnology company has announced a new price for sequencing an individual’s entire genome: $5,000. The announcement from the California start-up Complete Genomics signifies a drastic price drop–the going rate for a complete genome is currently about $100,000–and could allow researchers to routinely collect vast amounts of genetic information. Researchers say that a $5,000 genome would enable new studies to identify rare genetic variants linked to common diseases, and it could open up the sequencing market to diagnostic and pharmaceutical companies, making genome sequencing a routine part of clinical drug testing [ABC News].
Complete Genomics won’t offer its services directly to people who are curious about their genetic makeup, setting it apart from consumer-oriented companies like 23andMe and deCODE Genetics. Complete Genomics expects most of its customers to be pharmaceutical companies or research laboratories that are doing studies aimed at finding genes linked to diseases. Such studies might look at the DNA of 1,000 people with a disease and 1,000 people without the disease. Right now, such studies look at only particular locations in the DNA because it is too expensive to determine the entire DNA sequence. But presumably, an entire sequence would provide more complete information [The New York Times].
(more…)
Researchers have found a way to create stem cells from adult liver cells without triggering DNA changes that have caused mutations and tumors in previous studies. Though demonstrated only in mice so far, the result marks another key achievement in the fledgling science of cellular reprogramming. The hope is to create human, embryonic-like stem cells — which can be turned into all the other tissue types of the body — without using eggs or destroying embryos. That freshly derived tissue could then be transplanted into patients to treat various diseases [The Wall Street Journal].
A method of using adult cells to create stem cells was debuted by Japanese researchers in 2006. By using viruses to insert key developmental genes, researchers coaxed human skin cells into an embryonic state, capable of growing into almost any other type of tissue…. But there was a catch: Viruses used to reset the cells tended to fuse with their DNA, leading to unpredictable mutations and cancer. The cells were promising in principle, but couldn’t be used medically [Wired News]. In the new breakthrough, researchers used a different kind of virus to introduce the genes, and found that it didn’t leave behind any damaging genetic code.
(more…)
A new method to identify an individual’s genetic profile from a larger pool of genetic data could be a boon for forensic science, but is causing headaches for the National Institutes of Health. In response to a study describing the technique, the NIH quickly removed several publicly available databases of DNA information drawn from medical studies, citing concerns that patients’ privacy could be threatened.
The new type of DNA analysis could only identify an individual if that person’s genetic profile was already known. Such a confirmation could reveal patients’ participation in a study about a specific medical condition, denying them their presumed confidentiality, experts said [Los Angeles Times]. NIH officials say they took down the databases, which contained genetic data from more than 60,000 patients, as a precautionary measure, and say it’s unlikely that the privacy of any of those patients has been violated.
(more…)
Scientists have produced the cells that make up delicate inner ear hairs in mouse embryos, a step that could point the way to reversing hearing loss and curing congenital deafness. Sensory hair cells inside the cochlea, the auditory portion of the inner ear, convert sound waves into electrical impulses that are delivered to the brain. The loss of these minute hairs, or the nerves that control them, is the most common cause of hearing impairment and so-called nerve deafness [ABC Science].
Researchers used gene therapy to create the crucial cells: They used a virus to introduce a gene into the mice embryos, which caused non-sensory cells to turn into cochlear hair cells. While this preliminary experiment was done on normal-hearing mice, the discovery that the engineered cochlear cells functioned as well as natural cells was an important step. Says lead researcher John Brigande: “One approach to restore auditory function is to replace defective cells with healthy new cells…. Our work shows that it is possible to produce functional auditory hair cells in the mammalian cochlea” [Reuters].
(more…)
