GLIA RESPONSE TO ISCHEMIA IN NEURON GLIA CULTURES: LIPID DROPLET FORMATION, INFLAMMATION AND CROSSTALK BETWEEN CELL TYPES

Recent studies demonstrated that misregulation of lipid metabolism in microglia and macrophages plays a role in brain pathologies. Lipid droplets (LD) are intracellular organelles that ensure secure lipid storage for energy needs and they protect the cell against stressful conditions. However, in pathological conditions, such as cerebral ischemia, LD overload may impair the phagocytic activity of microglia compromising tissue repair.
To clarify the contribution of LD in astrocytes and microglia to the ischemic cascade, the aim of the present study is to characterize the LD biogenesis and explore how the regulation of lipid metabolism can affect inflammation and neuron survival in an ischemic environment.
We established a model of oxygen and glucose deprivation (OGD) in primary mixed neuron-glia cultures that causes 15-20 % of cell death at 24h, and we developed a workflow for image analysis in Imaris to detect LD in microglia and astrocytes.
Under this experimental setting, astrocytes and microglia exhibited LD in basal conditions. However, OGD alone did not increase the formation of LD. Conversely, OGD in combination with exogeneous cholesterol or myelin triggered the accumulation of LD in glial cells.
Our data show that the accumulation of LD in microglia and astrocytes exposed to ischemic conditions requires lipid supply from the extracellular environment.
Funding: This work is supported by the 2022-HR23-00560 grant from Fundacio La Caixa.