I mmunohistochemical Characterization of Microglia in a De‐identified Human Meningioma Brain Culture

Abstract

Background Microglia, the resident macrophages of the central nervous system, play an important role in immune defense by removing damaged neurons and cellular plaques. When activated microglia release pro‐inflammatory mediators (i.e. reactive oxygen intermediates, eicosanoids, cytokines, and metalloproteinases) which may contribute to the pathophysiology of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and HIV encephalopathy. Although rodent microglia have been used for immunological and pharmacological research, extrapolation of observations from rat microglia to human microglia has become challenging. Methods In 2017, a research collaboration was established between Neurosurgery at Cook County Hospital and the Pharmacology Department, College of Graduate Studies, Midwestern University. Several human brain biopsies were cultured in vitro and progressively developed into human brain tissue cultures. One of the human primary cultures (culture # 464) generated from a de‐identified human WHO grade I meningioma contained several cell types as determined by immunohistochemistry and described in 2019 (1). To further characterize microglia in brain culture # 464 three antibodies were used, namely against: A) cell surface integrin CD11b; B) the ionized calcium binding adaptor molecule 1 (Iba1), and C) the transmembrane proteinTMEM119. Results Immuno‐histochemistry observations appear to confirm the presence of microglia in de‐identified human WHO grade I meningioma brain culture # 464. Further studies will be required to confirm our current observations and determine a method to isolate viable microglia from culture # 464. Conclusions Microglia are present in de‐identified human brain culture # 464. Isolation of microglia would enable pharmacological and toxicological research with marine‐derived natural products and toxins in future studies (2). (1) T. Moazezi, et al. Characterization of de‐identified human brain culture by immunofluorescence. Chicago Chapter of the Society for Neuroscience, 4/19/2019, abstract F7, page 69. (2) Mayer, A.M.S., et al. Toxicological Sciences 149(2):484‐95, 2016. PMID: 26609141.