Microglia Limit Neurodegeneration Post Brain Injury

Microglial cells play vital roles in the brain, which include supporting neural function and development, specifically by clearing out dead cells, remodeling synapses, and maintaining blood vessels, to name a few (Eyo and Dailey, 2013). Referring to the paper, “Microglia: Key Elements in Neural Development, Plasticity, and Pathology,” understanding microglial function, development, and morphological activity leads to understanding neuropathological conditions. Dr. Dailey has studied microglia development in various Injury Models, such as: trauma, alcohol, stroke, environmental toxin exposure, and hypertension, and he studies the activity of microglia using in vitro and in vivo methods, and time-lapse fluorescence confocal and multiphoton imaging to capture the dynamic behavior of microglia (Dailey Lab).

            Before focusing on microglia in the stroke Injury Model, Eyo and Dailey's paper states analogies to understand the roles of microglia, one of which states that microglia can be viewed as “morticians,” which use their phagocytic ability to remove dead cells and other cellular debris in the brain (Eyo and Dailey, 2013). Dr. Dailey explains that as cells die, like in the case of strokes, the damaged cells can release “cytotoxic substances” into the space around them, which may injury the surrounding healthy cells, which makes microglial debris clearance an imperative role (Eyo and Dailey, 2013). Thereby showing that microglia may be used to lessen damage done after strokes and other brain injuries. The time-lapse fluorescence confocal imaging does justice to the dynamism of microglia; the video presented by Dr. Dailey shows the extension of microglial cytoplasmic projections through the space around them in order to identify and target areas in need of clearance and phagocytosis of debris (Seminar, 10/30/2018). Both the surveillance and clearance ability of microglia aid in limiting neurodegeneration.

            Similarly, at the University of Virginia School of Medicine, researchers have also related microglial phagocytic ability to decreases likelihood of “extensive neurodegeneration” after a brain injury, such as a stroke (Rockefeller University Press). Jonathan Kipnis, chairman of University of Virginia's Department of Neuroscience, and his colleagues came to the same idea of the role of microglia in removing toxic debris. Kipnis and his colleagues also found that microglia produce “complement” proteins that aid other microglia in finding their target cells to phagocytose (Rockefeller University Press), which reveals the complex cooperation of these supporting cells in the central nervous system. Kipnis and collegues have studied microglia post-injury, and through experimental depletion of microglia they found that microglia are the “dominant postinjury phagocytes,” (Rockefeller University Press) which provides evidence that microglia are crucial in helping the brain heal after an injury.

            Both Dailey’s and Kipnis’s studies reveal the essential function of microglia in limiting degeneration from brain injuries, through the function of clearing out debris and cytotoxins. These microglial studies shine light on the possibility of manipulating microglia to use as treatment or therapy for brain injuries.

Works Cited

Dailey, Michael E. “College of Liberal Arts & Sciences | The University of Iowa.” Dailey Lab, <dailey.lab.uiowa.edu>.

Eyo U., Dailey M.E. (2013) Microglia: Key Elements in Neural Development, Plasticity, and Pathology. J. Neuroimmune Pharmacol. 8:494-509.

Rockefeller University Press. "Brain cells responsible for removing damaged neurons after injury identified." ScienceDaily. ScienceDaily, 25 June 2018. <www.sciencedaily.com/releases/2018/06/180625122540.htm>.