Skip to main content
  • U.S. Department of Health & Human Services
National Institutes of Health (NIH) - Turning Discovery into Health
  • Virtual Tour
  • En Español

Site Menu

  • Home
  • Health Information
    • Health Care Providers & Facilities
    • Health Info Lines
    • HealthCare.gov
    • Science Education Resources
    • NIH Clinical Research Trials and You
    • Talking to Your Doctor

    More »

    Quick Links

    • MedlinePlus Health Info
    • NIH News in Health
    • Wellness Toolkits
  • Grants & Funding
    • Grants Home Page
    • Find Funding
    • Due Dates
    • How to Apply
    • About Grants
    • Policy & Compliance
    • Grants News/Blog
    • Contracts
    • Loan Repayment

    More »

    Quick Links

    • RePORT
    • eRA Commons
    • NIH Common Fund
  • News & Events
    • News Releases
    • Digital Media Kits
    • Media Resources
    • Media Contacts
    • Images and B-roll
    • Events
    • Social Media

    More »

    Quick Links

    • NIH News in Health
    • NIH Research Matters
    • NIH Record
  • Research & Training
    • Medical Research Initiatives
    • Science Highlights
    • Science Education
    • Research in NIH Labs & Clinics
    • Training Opportunities
    • Library Resources
    • Research Resources
    • Clinical Research Resources
    • Safety, Regulation and Guidance

    More »

    Quick Links

    • PubMed
    • Stem Cell Information
    • OppNet
    • NIDB
    • NIH Blueprint for Neuroscience Research
  • Institutes at NIH
    • List of Institutes and Centers
    • NIH Office of the Director
    • Directors of NIH Institutes and Centers
    • NIH Institute and Center Contact Information

    More »

    Quick Links

    • NCI
    • NEI
    • NHLBI
    • NHGRI
    • NIA
    • NIAAA
    • NIAID
    • NIAMS
    • NIBIB
    • NICHD
    • NIDCD
    • NIDCR
    • NIDDK
    • NIDA
    • NIEHS
    • NIGMS
    • NIMH
    • NIMHD
    • NINDS
    • NINR
    • NLM
    • CC
    • CIT
    • CSR
    • FIC
    • NCATS
    • NCCIH
  • About NIH
    • Who We Are
    • What We Do
    • Jobs at NIH
    • Visitor Information
    • Frequently Asked Questions
    • Contact Us

    More »

    Quick Links

    • The NIH Director
    • Take the Virtual Tour
    • NIH…Turning Discovery Into Health®
    • Impact of NIH Research
    • Science, Health, and Public Trust

You are here

Home » News & Events » News Releases

News Releases

News Release

Tuesday, April 11, 2017

NIH researchers trace origin of blood-brain barrier ‘sentry cells’

Finding in zebrafish may contribute to understanding cognitive decline of aging.

Image of an adult zebrafish brain An adult zebrafish brain showing fluorescent granular perithelial cells (green) atop blood vessels (purple).

National Institutes of Health researchers studying zebrafish have determined that a population of cells that protect the brain against diseases and harmful substances are not immune cells, as had previously been thought, but instead likely arise from the lining of the circulatory system.

This basic science finding may have implications for understanding age-related decline in brain functioning and how HIV infects brain cells.

The study, appearing online in eLife, was conducted by researchers at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and National Human Genome Research Institute and the Japanese National Institute of Genetics.

 

The blood-brain barrier is the layer of cells that line the blood vessels of the brain. The inner cell layer that lines vessels, known as the endothelium, is present in all the blood vessels of the body. Within the blood vessels of the brain, endothelial cells and other adjacent cells form a tight barrier that helps to prevent toxins and microbes from entering the brain. Although their function is not completely understood, a special population of cells covering the blood vessels on the brain’s surface is thought to contribute to the organ’s protection. The cells act as sentries, engulfing toxins, cellular wastes and microbes and then encasing them in sphere-like structures called vesicles. These sentry cells are called fluorescent granular perithelial cells (FGPs) because the vesicles they contain give off a yellow glow in the presence of light.

In the current study, the researchers showed that FGPs are present on the surface of the zebrafish brain and that these blood vessel-associated FGPs do not arise from the immune system, as had been previously thought, but from endothelial cells themselves.

FGPs are thought to be important in a variety of human brain disorders and conditions. These cells appear to be a major entry point for HIV infection of the brain. Age-related decline in cognitive function is associated with a decline in the scavenging function of FGPs.  “Learning more about how FGPs function may lead to a greater understanding of dementia and other conditions,” said the study’s senior author, Brant Weinstein, Ph.D., of NICHD’s Section on Vertebrate Organogenesis.

The Weinstein lab studies zebrafish to understand how the blood and lymphatic systems develop.  Because the young fish are transparent, it is possible to see the developing circulatory system while observing the fish under a light microscope. As part of this effort, Dr. Weinstein and his colleagues inserted a gene for a protein that turns green into the cells that line the endothelium of selected embryonic veins and in the lymphatic system — the network of vessels through which immune cells travel in the body. In addition to seeing green lymphatic cells in the zebrafish embryos, the researchers noticed that green cells also covered the surface of the tiny fish’s brains.

Upon closer inspection, the researchers tentatively identified these cells as FGPs. Because they turned green, it was apparent that they arose from endothelial cells. Until the current study, FGPs were thought to be macrophages, a type of immune cell. The researchers conducted additional experiments to confirm the origins of the FGPs, including analyzing what proteins were being made by their DNA. These proteins most closely resembled those made by endothelial cells in the lymphatic system, not the proteins made by macrophages or other immune cells. In another series of experiments, they inserted a green fluorescent protein into the tissues that give rise to blood and lymph vessels in embryonic zebrafish. Using time lapse photography, the researchers captured images of FGPs arising from the vessels’ endothelium. When zebrafish with the green fluorescing endothelial gene matured, the researchers observed green FGPs on the surface of the fish’s brains — confirming that these cells arose from endothelial tissue.

The researchers hope to conduct further studies of how FGPs interact with blood vessels and the blood-brain barrier. The researchers noted that, unlike mammals, embryonic zebrafish can be observed under a microscope as they develop, providing an easy means for studying the role of FGPs in protecting the brain.

About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD conducts and supports research in the United States and throughout the world on fetal, infant and child development; maternal, child and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit NICHD’s website.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

NIH…Turning Discovery Into Health®

Reference

Galanternik, et al. A novel perivascular cell population in the zebrafish brain.

###

Institute/Center

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Contact

Robert Bock
Linda Huynh
301-496-5133

Multimedia

Connect with Us

  • Subscribe to news releases
  • RSS Feed

Connect with Us

  • Contact Us
  • X
  • Facebook
  • Instagram
  • YouTube
  • Flickr
  • More Social Media from NIH

Footer

  • NIH Home
  • Virtual Tour
  • En Español
  • Visitor Information
  • Frequently Asked Questions
  • Privacy Policy
  • Disclaimers
  • Accessibility
  • NIH Website Archives
  • Nondiscrimination Notice
  • Freedom of Information Act
  • No Fear Act
  • HHS Vulnerability Disclosure
  • Office of Inspector General
  • USA.gov

NIH…Turning Discovery Into Health®

National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892

U.S. Department of Health and Human Services

Back to Top