(Press-News.org) Contact information: Dov Smith
dovs@savion.huji.ac.il
972-258-82844
The Hebrew University of Jerusalem
Scientists find a new mechanism underlying depression
Hebrew University research could lead to efficient and fast-acting antidepressant drugs
The World health Organization calls depression "the leading cause of disability worldwide," causing more years of disability than cancer, HIV/AIDS, and cardiovascular and respiratory diseases combined. In any given year, 5-7% of the world's population experiences a major depressive episode, and one in six people will at some point suffer from the disease.
Despite recent progress in understanding depression, scientists still don't understand the biological mechanisms behind it well enough to deliver effective prevention and therapy. One possible reason is that almost all research focuses on the brain's neurons, while the involvement of other brain cells has not been thoroughly examined.
Now researchers at the Hebrew University of Jerusalem have shown that changes in one type of non-neuronal brain cells, called microglia, underlie the depressive symptoms brought on by exposure to chronic stress. In experiments with animals, the researchers were able to demonstrate that compounds that alter the functioning of microglia can serve as novel and efficient antidepressant drugs.
The findings were published in Molecular Psychiatry, the premier scientific journal in psychiatry and one of the leading journals in medicine and the neurosciences. (See Dynamic microglial alterations underlie stress-induced depressive-like behavior and suppressed neurogenesis).
The research was conducted by Prof. Raz Yirmiya, director of the Hebrew University's Psychoneuroimmunology Laboratory, and his doctoral student Tirzah Kreisel, together with researchers at Prof. Yirmiya's laboratory and at the University of Colorado in Boulder, USA.
The researchers examined the involvement of microglia brain cells in the development of depression following chronic exposure to stress. Comprising roughly 10% of brain cells, microglia are the representatives of the immune system in the brain; but recent studies have shown that these cells are also involved in physiological processes not directly related to infection and injury, including the response to stress.
The researchers mimicked chronic unpredictable stress in humans — a leading causes of depression — by exposing mice to repeated, unpredictable stressful conditions over a period of 5 weeks. The mice developed behavioral and neurological symptoms mirroring those seen in depressed humans, including a reduction in pleasurable activity and in social interaction, as well as reduced generation of new brain cells (neurogenesis) — an important biological marker of depression.
The researchers found that during the first week of stress exposure, microglia cells undergo a phase of proliferation and activation, reflected by increased size and production of specific inflammatory molecules, after which some microglia begin to die. Following the 5 weeks of stress exposure, this phenomenon led to a reduction in the number of microglia, and to a degenerated appearance of some microglia cells, particularly in a specific region of the brain involved in responding to stress.
When the researchers blocked the initial stress-induced activation of microglia with drugs or genetic manipulation, they were able to stop the subsequent microglia cell death and decline, as well as the depressive symptoms and suppressed neurogenesis. However, these treatments were not effective in "depressed" mice, which were already exposed to the 5-weeks stress period and therefore had lower number of microglia. Based on these findings, the investigators treated the "depressed" mice with drugs that stimulated the microglia and increased their number to a normal level.
Prof. Yirmiya said, "We were able to demonstrate that such microglia-stimulating drugs served as effective and fast-acting antidepressants, producing complete recovery of the depressive-like behavioral symptoms, as well as increasing the neurogenesis to normal levels within a few days of treatment. In addition to the clinical importance of these results, our findings provide the first direct evidence that in addition to neurons, disturbances in the functioning of brain microglia cells have a role in causing psychopathology in general, and depression in particular. This suggests new avenues for drug research, in which microglia stimulators could serve as fast-acting antidepressants in some forms of depressive and stress-related conditions."
INFORMATION:
The Hebrew University's technology transfer company, Yissum, has applied for a patent for the treatment of some forms of depression by several specific microglia-stimulating drugs.
Scientists find a new mechanism underlying depression
Hebrew University research could lead to efficient and fast-acting antidepressant drugs
2014-01-08
ELSE PRESS RELEASES FROM THIS DATE:
Lower fat content and exercise for the diet of adolescents
2014-01-08
Lower fat content and exercise for the diet of adolescents
A study by the UPV/EHU-University of the Basque Country links dietary fat content with the excess of abdominal fat in adolescents, irrespective of the physical exercise they do
This news release is available ...
Study explains origins of giant underwater waves
2014-01-08
Study explains origins of giant underwater waves
Large-scale tests in the lab and the South China Sea reveal the origins of underwater waves that can tower hundreds of feet
CAMBRIDGE, Mass-- Their effect on the surface of the ocean is negligible, producing ...
Older firefighters may be more resilient to working in heat
2014-01-08
Older firefighters may be more resilient to working in heat
FALLS CHURCH, Va. (January 8, 2014) — Older firefighters who are chronically exposed to heat stress on the job could be more heat resilient over time. A recent study published in the December ...
Scientists make your stomach turn bright green if you have an ulcer
2014-01-08
Scientists make your stomach turn bright green if you have an ulcer
Doctors may soon be able to diagnose stomach ulcers without taking tissue samples from the stomach. Researchers from the University of Southern Denmark now report to have developed a new, safer and noninvasive ...
Does the body's immune response to viral vector delivery systems affect the safety or efficacy of gene therapy?
2014-01-08
Does the body's immune response to viral vector delivery systems affect the safety or efficacy of gene therapy?
New Rochelle, NY, January 7, 2014—Packaging replacement genes in viruses is an effective method to deliver them to target ...
Research reveals new therapeutic target for Huntington's disease
2014-01-08
Research reveals new therapeutic target for Huntington's disease
Geography has impact on grapevine moth's success in French vineyards
2014-01-08
Geography has impact on grapevine moth's success in French vineyards
Study sheds light on how regional differences, local temperatures influence immune function of pests
'Location, location, location' is an adage also true for the European grapevine moth, it seems. Research ...
Laundering money -- literally -- could save billions of dollars
2014-01-08
Laundering money -- literally -- could save billions of dollars
A dollar bill gets around, passing from hand to hand, falling on streets and sidewalks, eventually getting so grimy that a bank machine flags it and sends it to the shredder. Rather than destroying ...
Newly discovered celestial object defies categories
2014-01-08
Newly discovered celestial object defies categories
Scientists asking if it is a new kind of planet or a rare kind of failed star
TORONTO, ON – An object discovered by astrophysicists at the University of Toronto (U of T) nearly 500 light years away from the Sun ...
Metal ink could ease the way toward flexible electronic books, displays
2014-01-08
Metal ink could ease the way toward flexible electronic books, displays
Scientists are reporting the development of a novel metal ink made of small sheets of copper that can be used to write a functioning, flexible electric circuit on regular printer paper. ...
LAST 30 PRESS RELEASES:
Revised diagnostic criteria for vascular cognitive impairment and dementia—The VasCog-2-WSO criteria
The ATREIDES program in search of lost exo-Neptunes
Ancient crop discovered in the Canary Islands thanks to archaeological DNA
Placental research may transform our understanding of autism and human brain evolution
Mapping the Universe, faster and with the same accuracy
Study isolates population aging as primary driver of musculoskeletal disorders
Designing a sulfur vacancy redox disruptor for photothermoelectric and cascade‑catalytic‑driven cuproptosis–ferroptosis–apoptosis therapy
Recent advances in dynamic biomacromolecular modifications and chemical interventions: Perspective from a Chinese chemical biology consortium
CRF and the Jon DeHaan Foundation to launch TCT AI Lab at TCT 2025
Canada’s fastest academic supercomputer is now online at SFU after $80m upgrades
Architecture’s past holds the key to sustainable future
Laser correction for short-sightedness is safe and effective for older teenagers
About one in five people taking Ozempic, Wegovy or Mounjaro say food tastes saltier or sweeter than before
Taking semaglutide turns down food noise, research suggests
Type 2 diabetes may double risk of sepsis, large community-based study suggests
New quantum sensors can withstand extreme pressure
Tirzepatide more cost-effective than semaglutide in patients with knee osteoarthritis and obesity
GLP-1 drugs shown cost-effective for knee osteoarthritis and obesity
Interactive apps, AI chatbots promote playfulness, reduce privacy concerns
How NIL boosts college football’s competitive balance
Moffitt researchers develop machine learning model to predict urgent care visits for lung cancer patients
Construction secrets of honeybees: Study reveals how bees build hives in tricky spots
Wheat disease losses total $2.9 billion across the United States and Canada between 2018 and 2021
New funding fuels development of first potentially regenerative treatment for multiple sclerosis
NJIT student–faculty team wins best presentation award for ant swarm simulation
Ants defend plants from herbivores but can hinder pollination
When the wireless data runs dry
Inquiry into the history of science shows an early “inherence” bias
Picky eaters endure: Ecologists use DNA to explore diet breadth of wild herbivores
Study suggests most Americans would be healthier without daylight saving time
[Press-News.org] Scientists find a new mechanism underlying depressionHebrew University research could lead to efficient and fast-acting antidepressant drugs