Astrocyte Orai1 signaling promotes spinal excitatory synaptic potentiation and neuropathic pain after nerve injury in male mice

ABSTRACT: Neuropathic pain after peripheral nerve injury is a multifactorial condition mediated partly by inflammation in the spinal cord that results in potentiation of excitatory synaptic transmission in nociceptive circuits. Glial cells including astrocytes are key mediators of the underlying inflammation, but the signaling checkpoints that regulate astrocyte-driven spinal cord inflammation and sensitization of nociceptive circuits are not well understood. Here, we identify Orai1-mediated store-operated Ca2+ entry (SOCE) as an important regulator of spinal astrocyte cytokine production, metabolic reprogramming, and pain hypersensitivity in mice. Conditional deletion of Orai1 in astrocytes attenuated mechanical allodynia after nerve injury in male but not female mice, despite comparable SOCE suppression in both sexes. Orai1 deficiency also attenuated production of proinflammatory cytokines after SOCE activation, including TNFα, IL-6, and IL-33, both in vivo and in vitro. Electrophysiological recordings revealed that astrocyte Orai1 deletion prevented injury-induced enhancement of glutamatergic synaptic transmission in dorsal horn neurons, linking astrocytic Ca2+ signaling to central sensitization. Metabolomic profiling showed that Orai1 loss disrupted glycolysis and TCA cycle intermediates while promoting accumulation of immunomodulatory metabolites such as itaconate, consistent with a less inflammatory astrocyte metabolic state. These findings identify Orai1 channels as integrators of astrocyte Ca2+ signaling, immunometabolism, and excitatory synaptic potentiation after nerve injury, and identify a sexually dimorphic astrocyte mechanism governing neuropathic pain pathogenesis. Targeting astrocyte Orai1 channels may provide a selective therapeutic strategy for male-predominant chronic pain.