Abstract

Healthy functioning of cells within the Central Nervous System (CNS) requires a homeostatic microenvironment. This homeostasis can be disrupted by bodies such as protein aggregates (E.g. β-Amyloid plaques, α-Synuclein) and apoptotic neurons, leading to both acute and chronic inflammation, or neuroinflammation.
Microglia make up 10-20% of the total CNS cell population and are the resident immune cell responsible for the CNS immune response. In a resting state they survey their microenvironment for threats to homeostasis. Once activated they employ a number of phenotypic responses to protect neuronal function (migration towards perceived threats, proliferation, cytokine release and phagocytosis), all of which can be measured to determine a compound’s effect on neuroinflammation.
This work describes development of a phagocytosis assay using a variety of phagocytotic particles (E. coli or Zymosan bioparticles, β-Amyloid or α-Synuclein peptides or apoptotic cells) labelled with the pH sensitive pHrodo dye that exhibits an increase in fluorescence when within the acidic environment of the phagosome. The assay was used to functionally profile microglia cells from a variety of sources, including both mouse and human immortalised cell lines and human primary and iPSC derived cells.