A newly discovered part of the brain acts as a shield and watchdog

Researchers have discovered a previously unknown part of brain anatomy where immune cells act as both a protective barrier and platform to monitor brain infection and inflammation.

From the complexity of neural networks to basic biological functions and structures, the human brain only reluctantly reveals its secrets.

Advances in neuroimaging and molecular biology have enabled scientists to study the living brain at a previously unattainable level of detail, revealing many of its mysteries.

The new research comes from the lab of Miken Nedergaard, co-director of the Center for Translational Neuromedicine at the University of Rochester and the University of Copenhagen, and Keld Morgaud, professor of neuroanatomy at the University of Copenhagen.

Nedergaard and her colleagues changed our understanding of the basic mechanisms of the human brain and made important discoveries in the field of neuroscience. This includes many important functions of previously overlooked cells in the brain called glia, as well as details of the brain’s unique waste removal processes.lab named glyphatic system.

“Discovery of new anatomical structures that help separate and control blood flow. cerebrospinal fluid (CSF) in and around the brain has led to a deeper understanding of its sophisticated role in not only transporting and removing waste products from the brain, but also supporting its immune defenses. ” said Nedergaard.

This research focuses on the series of membranes that wrap around the brain, creating a barrier from the rest of the body and keeping the brain bathed in CSF. identifies three distinct layers: dura mater, arachnoid mater, and pia mater.

A new layer, discovered by a team of researchers based in the United States and Denmark, further divides the subarachnoid space, the space between the arachnoid and pia mater layers, into two compartments, separated by a newly described layer. increase. Membrane like.

Although many of the studies in this paper describe the function of SLYM in mice, they also report the presence of SLYM in the adult human brain.

SLYM is a type of membrane called mesothelium that covers other organs in the body, such as the lungs and heart. These membranes typically surround and protect organs and house immune cells. The idea that similar membranes might exist in the central nervous system was a question first posed by the lead author of this study, his Møllgård. Møllgård’s research focuses on developmental neurobiology and the barrier systems that protect the brain.

The new membrane is very thin and delicate, consisting of only a few cells in thickness. However, SLYM is a tight barrier that allows only very small molecules to pass through, and also appears to separate ‘clean’ and ‘dirty’ CSF.

This last observation suggests a likely role played by SLYM in the lymphatic system. This requires a controlled flow and exchange of CSF, allowing an influx of fresh CSF while toxic protein Associated with Alzheimer’s disease and other neurological disorders of the central nervous system.

This finding will help researchers better understand the mechanisms of the glymphatic system.

SLYM also appears to be important in brain defense. The central nervous system maintains a unique population of immune cells and membrane integrity prevents invasion by foreign immune cells. Moreover, this membrane appears to host a unique population of central nervous system immune cells that use the SLYM as a point of observation close to the surface of the brain, allowing her CSF passing through it to be screened for signs of infection or inflammation. Scan.

The discovery of SLYM has opened the door for further study of the role of SLYM in brain diseases. For example, researchers note that during inflammation and aging, immune cells congregate in larger and more variable concentrations in membranes. Furthermore, membrane rupture during traumatic brain injury disrupted CSF flow, compromised the lymphatic system, and allowed non-central nervous system immune cells to enter the brain.

These and similar observations suggest that diseases as diverse as multiple sclerosis, central nervous system infections and Alzheimer’s disease may be caused or exacerbated by abnormal SLYM function. They also suggest that drug and gene therapy delivery to the brain may be affected by SLYM, and this should be taken into account as new generations of biologic therapies are being developed. I have.

The research will be published in a journal chemistryAdditional co-authors are from the University of Copenhagen.

Support for this research is from the Lundbeck Foundation, Novo Nordisk Foundation, National Institute of Neurological Disorders and Stroke, U.S. Army Research Service, Human Frontier Science Program, Dr. Miriam and Sheldon G. Adelson Foundation for Medical Research, and The Simmons Foundation.

sauce: University of Rochester