Microglia and its role in neurodegenerative diseases

Microglia are immune cells colonized in the central nervous system (CNS) during the development of the embryo. They make up about 12% of the glial cell population in the brain. These cells play an important role in eliminating the damage that may occur in the CNS or in carrying out normal functions. Microglia cells, which are in morphologically inactive form, are characterized by small cell body, small amounts of cytoplasm and cellular extensions that are released towards the environment. They undergo a significant morphological change and switch to the active form in a pathophysiological condition in the CNS, and they have the ability to migrate to the damaged area by ameboid movement. In today's studies, microglial cells in the active form has been stated to show neuroprotective and neurotoxic effects in neuronal structures in addition to carrying out phagocytosis of metabolic residues in the medium. It has also been mentioned in recent studies that microglial cells located in the CNS have a highly sensitive activation mechanism against inflammation and pathological conditions. Understanding the microglial activation mechanism in neurodegenerative diseases is thought to may contribute to the diagnosis / treatment of neurological diseases as well as being a diagnostic marker for the etiology of the diseases. In this review, the general characteristics and activation mechanism of microglial cells and their functional roles in Alzheimer's, Parkinson's, epilepsy and multiple sclerosis diseases were discussed in the current review.