Store-operated calcium entry drives alcohol-exacerbated neuroinflammation in retinal degeneration.

Patients with neurodegenerative diseases such as retinitis pigmentosa (RP) may engage in maladaptive coping behaviors, including alcohol misuse, which can aggravate disease progression. Neuroinflammation, a hallmark of RP, is largely driven by microglial activation and amplified when cells are primed by oxidative stress. Store-operated calcium entry (SOCE), primarily mediated by Orai1 channels, regulates microglial metabolism and inflammatory signaling. Here, we tested whether ethanol (EtOH) exacerbates RP-related neuroinflammation through SOCE-dependent mechanisms and whether 2-aminoethoxydiphenyl borate (2-APB) mitigates these effects. In mixed retinal cultures, a "double-hit" (oxidative stress + EtOH) triggered pronounced microglial activation, neuronal loss, and altered cytokine expression and correlation patterns, assessed by multiplex bead assays and hierarchical clustering analysis. Indeed, 2-APB restored ramified morphology and improved neuronal survival. Conditioned medium experiments revealed that both microglia and Müller cells responded to the double-hit, but only microglia were sensitive to SOCE inhibition. In vivo, subretinal delivery of EtOH and 2-APB in rd1 mice, a genetic model of RP, altered microglial morphology and reduced pro-inflammatory cytokine levels without affecting photoreceptor density. Notably, in situ assessment of CD86/CD206 showed no change in expression, indicating that microglial activation in vivo is better captured by morphological and cytokine-network alterations than by classical surface markers. These findings show that alcohol misuse amplifies retinal neuroinflammation in RP via calcium-dependent mechanisms and identify SOCE as a therapeutic target for limiting damage from systemic comorbidities in retinal degeneration.