Microglia: Front Line Defenders of the Central Nervous System

Microglia play an essential role in brain homeostasis, neuroinflammation, neurodegenerative diseases, and brain infections. Microglia are integral components of the neuro-glial cell network and are the resident immune cells of the brain. Recent studies indicate that microglia are derived from the yolk sac and can self-renew. Microglia are distributed throughout the central nervous system (CNS) to perform brain immune surveillance. Microglia are also the first to respond to injury or infection in the brain and are important for development of the adult brain.

Under homeostatic conditions, the population of microglia is strictly regulated. As microglia are critical cells for the CNS, they perform a diverse array of functions such as scavenging, phagocytic debris removal, antigen presentation, synaptic organization, extracellular signaling and promoting repair. Upon activation, they act as brain macrophages to clear cellular debris, damaged cells, or microbes when programmed cell death occurs in brain development or when the CNS is damaged. Following injury or infection in the CNS, microglia act quickly by activating and releasing proinflammatory molecules, activating astrocytes, and enlisting cells from the peripheral immune system to aid in the response.

Microglia: Front Line Defenders of the Central Nervous System

As microglia are the primary components of the brain immune system, they also play a major role in neuroinflammation. Microglia are responsible for initiating the inflammatory process in the CNS and they have a direct effect on the local microenvironment in the brain. Microglia can secrete cytokines, chemokines and growth factors, which can either limit or promote tissue damage.  Although microglia are critical for the response to injury in CNS, they can also have detrimental effects if they become chronically activated due to continuous damage. Neurodegenerative disorders such as multiple sclerosis, Alzheimer’s disease, and Parkinson’s diseases are strongly linked to dysregulation of microglia and chronic microglia activation.  

Not surprisingly, microglia have been implicated in the neuroinflammation that develops during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Neurological issues have been previously detailed in both severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). Study of both viruses indicate that the viruses can directly infect the CNS, although the specific pathways are still unclear. Currently, it is not yet known whether microglia are simply responding directly to the virus as it gains access to the brain or whether they are reacting to the cytokine storm occurring in the body. Neuroinflammation of the brain may well occur in severe COVID-19 patients as the microglia respond to the threat of the virus.

Microglia are essential components of the CNS and understanding their role in infection and neurological diseases is vital for developing future therapeutic treatments. ScienCell Research Laboratories is currently offering primary Rat Microglia (Cat# R1900) for buy one, get one half off until October 5th. Rat Microglia are cryopreserved at P0 and have high purity. We also offer primary Mouse Microglia from both CD-1® mice (Cat# M1900) and C57BL/6 mice (Cat# M1900-57).

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