Potentially explaining why even healthy brains don't function well with age, researchers have discovered that genes that are switched on early in brain development to sever connections between neurons as the brain fine-tunes, are again activated in aging neuronal support cells called astrocytes. The work, which appeared in Cell Reports , suggests that astrocytes may be good therapeutic targets to prevent or reverse the effects of normal aging.
Although not nearly as well studied as neurons, astrocytes--named for their star-shaped appearance--make up one-third to one-half of all the cells in the brain and are increasingly being found to be critical for neuronal function.
Neuroscientists know that in the young, developing brain, synapses are being activated and deactivated, while in the adult brain they are mostly stable. But in aging brains, neurons start to lose connections and don't communicate as well. Researchers wondered whether the changes to synapses and neuronal communication during aging might be related to changes in astrocytes.
To find out, they decided to compare gene expression in astrocytes in the adult brain versus the aged brain in mice. This would give them an idea of which genes are active at the two stages. To develop a comprehensive view of astrocyte gene expression, the duo used the bibo-tag technique in four very different areas of the mouse brain: two regions of the cortex and the hypothalamus and cerebellum.
To their surprise, they found that most of the properties that make an astrocyte an astrocyte didn't change much with age--gene expression was fairly consistent with time. But what did change: genes that during development would normally cause the loss of connections between neurons were switched on again in the aging astrocytes. Aging astrocytes show minimal alteration of homeostatic and neurotransmission-regulating genes. However, aging astrocytes upregulate genes that eliminate synapses and partially resemble reactive astrocytes. Authors further identified heterogeneous expression of synapse-regulating genes between astrocytes from different cortical regions.
"This suggests that there's some sort of genetic program that's being reactivated in these astrocytes as they age that's causing neurons to lose their connections with each other," says the senior author.
Interestingly, the areas in which astrocytes looked the most different were brain areas where neurons are known to function notably less well with age or even to die--the cerebellum and the hypothalamus.
"This may explain why metabolism decreases and coordination gets worse with age, because these are functions that are coordinated by the hypothalamus and cerebellum," adds the graduate student.
The team has made their study data publicly available for other researchers to use. In future, the lab plans to compare aging astrocytes to astrocytes in models of disease to see whether there could be prepathological changes that allow the transition to disease to occur.
https://www.salk.edu/news-release/brains-support-cells-arent-supportive/
http://www.cell.com/cell-reports/fulltext/S2211-1247(17)31848-X
Developmental genes turn on in astrocytes during aging!
- 2,272 views
- Added
Edited
Latest News
Protein that helps COVID-19…
By newseditor
Posted 26 Jul
Spinal Muscular Atrophy (SM…
By newseditor
Posted 26 Jul
Link between bowel movement…
By newseditor
Posted 26 Jul
Inhibition of IL-11 signall…
By newseditor
Posted 25 Jul
Brain changes linked to obe…
By newseditor
Posted 25 Jul
Other Top Stories
Circadian rhythm controls fat production and burning!
Read more
A biological pathway that boosts our ability to build aerobic capac…
Read more
Blood test may identify gestational diabetes risk in first trimester
Read more
How the brain knows when to stop eating?
Read more
Fish oils do not prevent heart attack or strokes in people with dia…
Read more
Protocols
A systems biology approach…
By newseditor
Posted 24 Jul
quantms: a cloud-based pipe…
By newseditor
Posted 22 Jul
Emerging tools and best pra…
By newseditor
Posted 19 Jul
Directly selecting cell-typ…
By newseditor
Posted 17 Jul
PUFFFIN: an ultra-bright, c…
By newseditor
Posted 16 Jul
Publications
Hepatocyte-intrinsic SMN de…
By newseditor
Posted 26 Jul
Aberrant bowel movement fre…
By newseditor
Posted 26 Jul
A pseudoautosomal glycosyla…
By newseditor
Posted 26 Jul
Microglia protect against a…
By newseditor
Posted 26 Jul
Rigor and reproducibility i…
By newseditor
Posted 26 Jul
Presentations
Myelin plasticity in the ve…
By newseditor
Posted 10 Jun
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar