Certain cells secrete a substance in the brain that protects neurons, USC study finds

June 24, 2019

USC researchers have discovered a secret sauce in the brain's vascular system that preserves the neurons needed to keep dementia and other diseases at bay.

The finding, in a mouse model of the human brain, focuses on specific cells called pericytes and reveals that they play a previously unknown role in brain health. Pericytes secrete a substance that keeps neurons alive, even in the presence of leaky blood vessels that foul brain matter and result in cognitive decline.

The study, which appears today in Nature Neuroscience, helps explain the cascade of problems that lead to neurodegeneration after stroke or traumatic brain injury, as well as in diseases like Alzheimer's and Parkinson's -- and suggests a potential strategy for therapy.

"What this paper shows is if you lose these vascular cells, you start losing neurons. The link with neurodegeneration was really not that clear before," said senior author Berislav Zlokovic, director of the Zilkha Neurogenetic Institute at the Keck School of Medicine of USC.

The discovery comes at a time when scientists are beginning to understand Alzheimer's disease as the result of multiple processes that begin long before memory loss sets in. Many researchers are shifting their focus from the amyloid plaques that accumulate in the brain later in life toward other targets earlier in the timeline.

Zlokovic, for example, studies the layers of cells that make up blood vessels in the brain. His previous research shows that the more permeable, or leaky, a person's brain capillaries, the more cognitive disability they have.

For this new experiment in mice, Zlokovic zeroed in on pericytes in the brain's blood vessels. Pericytes help regulate blood flow and keep blood vessel walls sealed tight. When researchers artificially removed pericytes, they saw rapid degeneration of the blood-brain barrier, a slowdown of blood flow and the loss of brain cells.

To further understand the role of pericytes, the scientists infused mice with a protein, or growth factor, secreted by pericytes in the brain and not found elsewhere in the body. They found that, even with pericyte cells artificially removed, the growth factor protected neurons and the brain cells didn't die. The results persisted even with constricted blood flow.

Because these pericytes are implicated in many diseases -- including Huntington's, Parkinson's, stroke, brain trauma and amyotrophic lateral sclerosis -- the research offers intriguing possibilities for further investigation.

"This opens up an entirely new view of the possible pathogenesis of Alzheimer's disease," Zlokovic said.
-end-
In addition to Zlokovic, other authors -- all from the Keck School of Medicine -- include senior co-author Zhen Zhao; first co-authors Angeliki Nikolakopoulou, Axel Montagne, Kassandra Kisler and Zhonghua Dai; and Yaoming Wang, Mikko Huuskonen, Abhay Sagare, Divna Lazic, Melanie D. Sweeney, Pan Kong, Min Wang, Nelly Chuqui Owens, Erica Lawson and Xiaochun Xie.

The study was supported with grants from the National Institutes of Health (R01AG039452, R01NS100459, R01AG023084, R01NS090904 and R01NS034467) and the Foundation Leducq Transatlantic Network of Excellence for the Study of Perivascular Spaces in Small Vessel Disease.

University of Southern California

Related Blood Vessels Articles from Brightsurf:

Biofriendly protocells pump up blood vessels
In a new study published today in Nature Chemistry, Professor Stephen Mann and Dr Mei Li from Bristol's School of Chemistry, together with Associate Professor Jianbo Liu and colleagues at Hunan University and Central South University in China, prepared synthetic protocells coated in red blood cell fragments for use as nitric oxide generating bio-bots within blood vessels.

Specific and rapid expansion of blood vessels
Upon a heart infarct or stroke, rapid restoration of blood flow, and oxygen delivery to the hypo perfused regions is of eminent importance to prevent further damage to heart or brain.

Flexible and biodegradable electronic blood vessels
Researchers in China and Switzerland have developed electronic blood vessels that can be actively tuned to address subtle changes in the body after implantation.

Lumpy proteins stiffen blood vessels of the brain
Deposits of a protein called ''Medin'', which manifest in virtually all older adults, reduce the elasticity of blood vessels during aging and hence may be a risk factor for vascular dementia.

Cancer cells take over blood vessels to spread
In laboratory studies, Johns Hopkins Kimmel Cancer Center and Johns Hopkins University researchers observed a key step in how cancer cells may spread from a primary tumor to a distant site within the body, a process known as metastasis.

Novel function of platelets in tumor blood vessels found
Scientists at Uppsala University have discovered a hitherto unknown function of blood platelets in cancer.

Blood vessels can make you fat, and yet fit
IBS scientists have reported Angiopoietin-2 (Angpt2) as a key driver that inhibits the accumulation of potbellies by enabling the proper transport of fatty acid into general circulation in blood vessels, thus preventing insulin resistance.

Brothers in arms: The brain and its blood vessels
The brain and its surrounding blood vessels exist in a close relationship.

Feeling the pressure: How blood vessels sense their environment
Researchers from the University of Tsukuba discovered that Thbs1 is a key extracellular mediator of mechanotransduction upon mechanical stress.

Human textiles to repair blood vessels
As the leading cause of mortality worldwide, cardiovascular diseases claim over 17 million lives each year, according to World Health Organization estimates.

Read More: Blood Vessels News and Blood Vessels Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.