Anxa10 and neuropathic pain: Insights into dysregulation of endoplasmic reticulum-mitochondria contact tethering complex and therapeutic potential.

The stability of membrane contact sites is critically dependent on Endoplasmic Reticulum mitochondria contact tethering complexes (EMCTCs), and dysregulation of these sites has been implicated in neuropathic diseases. In this study, we examined the role of Annexin A10 (Anxa10), a calcium-dependent protein, in neuropathic pain by investigating its influence on EMCTCs dysregulation. Using RNA sequencing, western blotting, and behavioral assays, we observed that spared nerve injury (SNI)-induced neuropathic pain significantly increased Anxa10 expression levels within the spinal dorsal horn (SDH) of mice. By employing cell-specific gene regulation via the Cre/loxp system, we utilized loxp-modified adeno-associated virus vectors to modulate Anxa10 expression in GAD2-Cre (inhibitory neurons), vGlut2-Cre (excitatory neurons), and Fos-Cre (activity-induced neurons) transgenic mice. Our results demonstrated that specific down-regulation of Anxa10 in excitatory neurons within the SDH alleviated neuropathic pain, whereas up-regulation of Anxa10, regardless of cell type, induced spontaneous pain in mice. Ultrastructural analysis of the endoplasmic reticulum (ER) and mitochondria, as well as double immunofluorescence staining, revealed that downregulation of Anxa10 mitigated the SNI-induced reduction in ER-mitochondrial distance. Additionally, it attenuated the SNI-induced upregulation of key components of EMCTCs, including IP3R, GRP75, and VDAC1, while preventing the SNI-induced downregulation of NCX3 expression. Furthermore, we formulated and validated the hypothesis that SGK1 and PI3K are positioned downstream of Anxa10. The up-regulation of Anxa10 compromised mitochondrial integrity and disrupted mitochondrial networks, ultimately leading to elevated oxidative stress. Collectively, these findings suggest that Anxa10 represents a promising therapeutic target for correcting EMCTCs dysregulation and mitigating neuropathic pain.