Autotaxin regulates the expression and the activity of P-glycoprotein in lipopolysaccharide -activated microglial cells.

Abstract

Neurodegenerative diseases (NDs), such as Alzheimer's and Parkinson's, are characterized by chronic inflammation and oxidative stress, often mediated by activated microglial cells. Microglia-induced neuroinflammation is essential to neuronal damage, driven by the overproduction of pro-inflammatory cytokines and reactive oxygen species. Autotaxin (ATX), a lysophospholipase D enzyme, can modulate inflammation through its enzymatic product lysophosphatidic acid (LPA). While previous studies highlighted ATX's anti-inflammatory properties, its impact on P-glycoprotein (P-gp), a key efflux transporter involved in drug resistance and neuroinflammation, remains not fully understood. The objective of this study was to explore how ATX modulates the expression and activity of P-gp in lipopolysaccharide (LPS)-activated and H2O2-stressed BV-2 microglial cells. Microglial cells were transfected with either an empty vector (EV) or an ATX cDNA vector (A +) and exposed to LPS (1 µg/mL) or H2O2 (100 µM). The mRNA expression levels of P-gp and pro-inflammatory cytokines were analyzed using qRT-PCR, and P-gp activity was assessed using the NBD-CSA fluorescence efflux assay. Our findings revealed that while LPS- and H₂O₂-treated microglial cells were characterized by an abnormal cellular morphology with long ramified processes, ATX overexpression restored the round shape morphology normally observed in the control untreated cells. Interestingly, ATX overexpression significantly reduced the mRNA levels of pro-inflammatory cytokines, such as TNF-α, in LPS- and H₂O₂-treated microglial cells. Moreover, ATX overexpression reduced both the mRNA levels and efflux activity of P-gp under inflammatory and oxidative stress conditions. These results suggest that ATX mitigates microglial activation and its downstream effects, highlighting its therapeutic potential in reducing neuroinflammation.