Restoration of Immune Homeostasis: The Role of miR‐30b‐5p and Notch Signaling in Uveitis After Treatment With Longdan Xiegan Decoction

Uveitis is an inflammatory eye disease, and Longdan Xiegan Decoction (LXD) has been used to treat uveitis. However, the underlying mechanisms have not fully been addressed. The present study aimed to provide new insights into LXD ameliorating inflammatory response of experimental autoimmune uveitis (EAU) and regulating T helper (Th) cell differentiation via the interaction between microRNA (miRNA) and mRNA. The hub genes, corresponding miRNAs, and bioactive substances from the LXD formula that are involved in ameliorating uveitis were identified through the network pharmacology analysis. We investigated the efficacy of LXD on the pathogenesis of EAU in vivo using the Genesis-D camera and histopathological examination, and confirmed the inhibitory effect of miR-30b-5p on the Notch signaling pathway in vitro. The analysis results indicated that T-cell lineage commitment and the Notch signaling pathway activation are the primary inflammatory process associated with the therapeutic effects of LXD on uveitis. Further predictions revealed the miRNA-mRNA interactions between miR-30b-5p and the mRNAs associated with Notch1 and DLL4. The pathogenesis of uveitis involves elevated Notch1, DLL4, IL-17A, and RORγt, and decreased levels of miR-30b-5p. LXD can enhance miR-30b-5p expression, inhibit Notch signaling activation, and suppress the commitment of uveitogenic T-cell lineages. Additionally, it downregulates proinflammatory cytokines while upregulating antiinflammatory cytokines, thereby promoting the the expansion of Treg and Th2 cell lineages, and restoring the ratios of Th1/Th2 and Th17/Treg cells. Reduced expression of miR-30b-5p contributes to the pathogenesis of uveitis. LXD exhibited an inhibitory effect on Notch signaling activation through the miR-30b-5p upregulation and the regulation of the balance between Th1/Th2 and Th17/Treg cell differentiation, ultimately facilitating the treatment of uveitis.