Matsuda Yorishige, Tanaka Megumu, Zhao Yunlu, Kakihara Shinji, Hoshiyama Ken, Sakurai Takayuki, Kamiyoshi Akiko, Ichikawa-Shindo Yuka, Kawate Hisaka, Zhang Yan, Guo Qianqian, Li Peixuan, Li Jiake, Duan Jun, Hayashi Marina, Sanjo Hideki, Murata Toshinori, Shindo Takayuki
Department of Cardiovascular Research, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
Invest Ophthalmol Vis Sci. 2025 Jun 2;66(6):12. doi: 10.1167/iovs.66.6.12.
Adrenomedullin (AM), a peptide produced by various cells, exerts diverse physiological effects and is regulated by receptor activity-modifying proteins (RAMP2 and 3). Experimental autoimmune uveitis (EAU) is a well-established model for studying human autoimmune uveitis. Hence, we investigated the pathophysiological roles of the AM-RAMP system in uveitis using an optimized EAU mouse model.
Female wild-type (WT), AM knockout, RAMP2KO, and RAMP3KO mice were immunized with the human interphotoreceptor retinoid-binding protein. The expression of macrophage-related genes and inflammatory cytokines in the retina and spleen was analyzed using real-time polymerase chain reaction. EAU-induced WT mice received human recombinant AM; therapeutic effects were evaluated via clinical and histologic scores, quantification of T-cell and macrophage infiltration in the retina, and the number of splenic regulatory T cells (Tregs) and M2 macrophages using flow cytometry.
Compared with WT mice, EAU-induced AMKO and RAMP2KO mice had significantly increased retinal inflammatory cell infiltration and worsened clinical scores, whereas RAMP3KO mice did not. Proinflammatory cytokine expression was suppressed in the retina of EAU-induced WT mice that received AM. However, anti-inflammatory cytokine expression was upregulated compared with that in the vehicle group. Additionally, there was reduced retinal infiltration of T cells and macrophages, leading to improved clinical and histologic scores. AM administration also suppressed EAU-induced splenomegaly and increased the number of Tregs and M2 macrophages, possibly contributing to resolving inflammation.
AM exerts an anti-inflammatory effect in uveitis by activating Tregs and M2 macrophages through RAMP2. Its administration is a potential adjunctive therapy for uveitis.
肾上腺髓质素（AM）是一种由多种细胞产生的肽，具有多种生理作用，并受受体活性调节蛋白（RAMP2和RAMP3）调控。实验性自身免疫性葡萄膜炎（EAU）是研究人类自身免疫性葡萄膜炎的成熟模型。因此，我们使用优化的EAU小鼠模型研究了AM-RAMP系统在葡萄膜炎中的病理生理作用。
用人类光感受器间维生素A结合蛋白免疫雌性野生型（WT）、AM基因敲除、RAMP2基因敲除和RAMP3基因敲除小鼠。使用实时聚合酶链反应分析视网膜和脾脏中巨噬细胞相关基因和炎性细胞因子的表达。EAU诱导的WT小鼠接受人重组AM；通过临床和组织学评分、视网膜中T细胞和巨噬细胞浸润的定量以及使用流式细胞术检测脾调节性T细胞（Treg）和M2巨噬细胞的数量来评估治疗效果。
与WT小鼠相比，EAU诱导的AM基因敲除和RAMP2基因敲除小鼠视网膜炎性细胞浸润显著增加，临床评分恶化，而RAMP3基因敲除小鼠则没有。接受AM的EAU诱导的WT小鼠视网膜中促炎细胞因子表达受到抑制。然而，与载体组相比，抗炎细胞因子表达上调。此外，视网膜中T细胞和巨噬细胞浸润减少，导致临床和组织学评分改善。给予AM还可抑制EAU诱导的脾肿大，并增加Treg和M2巨噬细胞的数量，可能有助于炎症消退。
AM通过RAMP2激活Treg和M2巨噬细胞，在葡萄膜炎中发挥抗炎作用。其给药是葡萄膜炎的一种潜在辅助治疗方法。
