Many of the body’s processes follow a natural daily rhythm or so-called circadian clock. Continue reading
They looked at patients with Potocki-Shaffer syndrome, a rare disorder that can result in significant abnormalities such as a small head and chin and intellectual disability, and found the gene PHF21A was mutated, said Dr. Hyung-Goo Kim, molecular geneticist at the Medical College of Continue reading
What genetic changes account for the vast behavioral differences between humans and other primates? Researchers so far have catalogued Continue reading
In a look at how major stressors during childhood can change a person’s biological risk for psychiatric disorders, researchers at Butler Hospital have discovered a genetic alteration at the root of the association. The research, published online in PLoS ONE on January 25, 2012, suggests that childhood adversity may lead to epigenetic changes in the human glucocorticoid receptor gene, an important regulator of the biological stress response that may increase risk for psychiatric disorders.
The association between childhood adversity, including parental loss and childhood maltreatment, and risk for psychiatric disorders such as depression and anxiety has been established in multiple studies. However, researchers have yet to define how and why this association exists in humans. “We need to understand the biology of this effect in order to develop better treatment and prevention programs,” Continue reading
Medical researchers estimate that over 50% of cancers have defective “p53.” So what exactly is p53 and why does it play such a big part in cancer growth?
Normally, p53 is a gene that works to protect healthy cells when they are dividing. P53 lives in your cytoplasm, but if it senses a cell is coming under attack, it moves into the nucleus. If it detects a genetic error in the cell’s code, it stops the cell reproduction process to give the DNA a chance to repair. If the cell can’t be repaired, the cell kills itself — this is called “apoptosis.”
It sounds like a great safeguard system, doesn’t it? And it is — except when p53 becomes too aggressive. Continue reading
People with a certain gene trait are known to be more kind and caring than people without it, and strangers can quickly tell the difference, according to US research published on Monday.
The variation is linked to the body’s receptor gene of oxytocin, sometimes called the “love hormone” because it often manifests during sex and promotes bonding, empathy and other social behaviors.
Scientists at Oregon State University devised an experiment in which 23 couples, whose genotypes were known to researchers but not observers, were filmed.
One member of the couple was asked to tell the other about a time of suffering in his or her life. Continue reading
Humans and zebra fish share mechanisms that regulate our circadian system, says TAU researcher
Circadian rhythms — the natural cycle that dictates our biological processes over a 24-hour day — does more than tell us when to sleep or wake. Disruptions in the cycle are also associated with depression, problems with weight control, jet lag and more. Now Prof. Yoav Gothilf of Tel Aviv University‘s Department of Neurobiology at the George S. Wise Faculty of Life Sciences is looking to the common zebrafish to learn more about how the human circadian system functions.
Prof. Gothilf Continue reading
Mosquitoes make proteins to help them handle the stressful spike in body temperature that’s prompted by their hot blood meals, a new study has found.
The mosquito’s eating pattern is inherently risky: Taking a blood meal involves finding warm-blooded hosts, avoiding detection, penetrating tough skin and evading any host immune response, not to mention the slap of a human hand.
Until now, the stress of the hot blood meal itself has been overlooked, researchers say.
Scientists have determined in female mosquitoes Continue reading
A new study in fruit flies offers a broad view of the potent and sometimes devastating molecular events that occur throughout the body as a result of methamphetamine exposure.
The study, described in the journal PLoS ONE, tracks changes in the expression of genes and proteins in fruit flies (Drosophila melanogaster) exposed to meth.
Unlike most studies of meth, which focus on the brain, the new analysis looked at molecular changes throughout the body, said University of Illinois entomology professor Barry Pittendrigh, who led the research.
“One of the great things about working with fruit flies is that because they’re small, we Continue reading
Looking at the dark stripes on the tiny zebra fish you might not expect that they hold a potentially important clue for discovering a treatment for the deadly skin disease melanoma. Yet melanocytes, the same cells that are responsible for the pigmentation of zebra fish stripes and for human skin color, are also where melanoma originates. Craig Ceol, PhD, assistant professor of molecular medicine at the University of Massachusetts Medical School, and collaborators at several institutions, used zebra fish to identify a new gene responsible for promoting melanoma. In a paper featured on the cover of the March 24 issue of Nature, Dr. Ceol and colleagues describe the melanoma-promoting gene SETDB1. Continue reading
WASHINGTON – A gene that influences how the brain responds to stress may also play a key role in depression, according to a new study.
Numerous studies have shown that the brain molecule neuropeptide Y (NPY) helps to restore calm after stressful events.
However, a team of University of Michigan-led researchers has found that people whose genes predispose them to produce lower levels of NPY have a more intense negative emotional response to stress and may be more likely to develop a major depressive disorder.
They now hope the research will eventually help with early diagnosis and intervention for depression and other psychiatric illnesses, and could help lead the way toward developing more individualized therapies.
“We’ve identified a biomarker – in this case genetic variation – that is linked with increased risk of major depression,” said the study’s senior author Jon-Kar Zubieta, a professor of psychiatry and radiology and research professor at the Molecular and Behavioral Neurosciences Institute.
“This appears to be another mechanism, independent of previous targets in depression research, such as serotonin, dopamine and norepinephrine,” he added.
The study found that people who produce lower amounts of NPY had measurably stronger brain responses to negative stimuli and psychological responses to physical pain.
They were also over-represented in a population diagnosed with a major depressive disorder.
The researchers used three different approaches, each with a varying number of research subjects ranging from 58 to 152, to study the link between NPY gene expression and emotional processing.
First, they classified subject participants into three categories according to low, medium or high NPY expression.
Using functional magnetic resonance imaging (fMRI), they then observed the brain activity as the subjects viewed different words – some neutral (such as ‘material’) negative (like ‘murderer’), and positive words (like ‘hopeful’).
In response to negative words, subjects in the low NPY group showed strong activation in the prefrontal cortex, which is involved with processing emotion, while subjects with high NPY demonstrated a much smaller response.
In the second trial, researchers looked at how subjects described their emotional state before and after a stress challenge in which saline solution was injected into their jaw muscles, causing moderate pain for about 20 minutes.
Those in the low NPY group were more negative both before and after the pain – meaning they were more emotionally affected while anticipating the pain and while reflecting on their experience immediately afterward.
Finally, the researchers compared the NPY genotypes of subjects with major depressive disorders with control subjects and found that people with low NPY were ‘over-represented’ in the group with depression.
“These are genetic features that can be measured in any person. We hope they can guide us toward assessing an individual’s risk for developing depression and anxiety,” said lead author Brian Mickey, an assistant professor in the Department of Psychiatry at the University of Michigan Medical School.
The findings are published in the Archives of General Psychiatry.
Front temporal dementia is caused by a breakdown of nerve cells in the frontal and temporal region of the brain (fronto-temporal lobe), which leads to, among other symptoms, a change in personality and behavior. The cause of some forms of front temporal dementia is a genetically determined reduction of a hormone-like growth factor, progranulin. Scientists around Dr. Anja Capell and Prof. Christian Haass have now shown that various drugs that are already on the market to treat malaria, angina pectoris or heart rhythm disturbances can increase the production of progranulin. Accordingly, these drugs are good candidates for treatment of this specific form of front temporal dementia. The work will be published in the online edition of the scientific journal, Journal of Neuroscience on February 2nd, 2011.
Progranulin is needed in the human brain as a protective factor for sensitive nerve cells, too little progranulin therefore results in a progressive neuronal cell death. As for almost every other gene, there are also two copies of the progranulin gene in the cell. In patients with progranulin dependent front temporal dementia, one of the two copies is defective, leading to a 50% reduction in progranulin levels. To rescue the lack of progranulin, the Munich researchers tested various substances for their ability to stimulate the remaining progranulin production and identified a drug called bafilomycin (BafA1). They then examined the molecular mechanism underlying the impact of BafA1 on progranulin more closely. Growth factors such as progranulin are produced in cellular membrane inclusions, known as vesicles. BafA1 has an alkalizing effect on these vesicles: After administration of BafA1 the interior of the vesicles is less acidic – and this increases the production of progranulin.
This observation encouraged the researchers to investigate further alkalizing substances for their ability to raise progranulin levels. Among the substances that passed the test were three drugs that are already on the market to treat various diseases: a medication for angina pectoris (bepridil), one for heart rhythm problems (amiodarone) and the widely used malaria drug chloroquine. Chloroquine increased the progranulin level not only in experiments with mouse cells to normal, but also in cells from patients with the defective progranulin gene.
In a clinical study in collaboration with the University of London, the team of Prof. Haass and Dr. Capell will now investigate whether chloroquine actually helps against progranulin dependent front temporal dementia. The human studies can be started very soon, as chloroquine has been used on countless patients, so that serious side effects are not to be expected. Even though the Munich scientists are optimistic, Prof. Haass warns against exaggerated hopes. “Experience shows that the step from cell and animal models to the patient is always connected with considerable difficulties. It will take several years until we know, whether chloroquine can be used as therapy for progranulin dependent front temporal dementia,” says Haass.