In vitro generated human microglia derived from blood precursors (111.14)

Abstract

Microglia as the resident innate immune cells of the brain share common characteristics with monocyte-macrophage lineage such as expression of surface markers and chemokine/cytokine receptors. To date, there is no standardized simple model available to investigate the biology of human microglia. The aim of this study is to establish a new in vitro microglia model using blood-derived precursor cells. For that purpose, human peripheral blood monocytes were cultured in serum free medium in the presence of M-CSF, GM-CSF, NGF and CCL2 to generate monocyte-derived microglia (M-MG).M-MG were clearly different in morphology, phenotype and function from freshly isolated monocyte-derived dendritic cells (M-DC).M-MG acquired a ramified morphology with primary and secondary processes .M-MG displayed a comparable phenotype to the human microglia cell line HMC3, expressing very low levels of CD45, CD14 and HLA-DR, CD11b and CD11c; and a distinct pattern of chemokine receptors (CCR1, CCR2, CCR4, CCR5, CXCR1, CXCR3, CX3CR1).In comparison with M-DC, M-MG displayed lower T-lymphocyte stimulatory capacity as well as lower phagocytosis activity.The described protocol for the generation of human monocyte-derived microglia is feasible, well standardized and reliable, as it uses well defined culture medium and recombinant cytokines, but no serum or conditioned medium. This protocol will certainly be very helpful for future studies investigating the biology and pathology of human microglia.