P2X7 inhibition prevents mitochondrial stress caused by alcohol and e‐cigarette exposure in primary vascular endothelial cells and restores barrier function

Abstract

Studies in both human and animal models demonstrated that chronic alcohol/e‐cigarette (e‐Cig) exposure affects mitochondrial function and impairs barrier function in brain microvascular endothelial cells (BMVEC). Identification of the signaling pathways by which chronic alcohol/e‐Cig exposure induces mitochondrial damage in BMVEC is vital for protection of the blood‐brain barrier. We treated primary human BMVEC with ethanol (100 mM) or e‐Cig conditioned medium and showed reduced mitochondrial oxidative phosphorylation (OXPHOS) analyzed by a Seahorse analyzer. Chronic alcohol/e‐Cig treatment significantly reduced the expression of mitochondrial OXPHOS proteins and pyruvate dehydrogenase (a vital enzyme in the TCA cycle) detected by western blot. We observed the cytosolic escape of ATP and its extracellular release due to the disruption of mitochondrial membrane potential after alcohol or e‐Cig treatment of BMVEC. Further, alcohol or e‐Cig treatment resulted in an elevated purinergic receptor (P2X7) and TRPV1 channel expression by qPCR in primary BMVEC. We showed a protective role of the P2X7r antagonist which restored the mitochondrial oxidative phosphorylation levels and prevented ATP release. In summary, we identified potential common pathways of mitochondrial injury caused by alcohol and e‐Cig which allow new protective interventions. We are further investigating the potential link between P2X7 regulatory pathways and mitochondrial health.