Department of Ophthalmology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510220, P.R. China.
Mol Med Rep. 2024 Dec;30(6). doi: 10.3892/mmr.2024.13337. Epub 2024 Sep 27.
Although both mucin1 (MUC1) and transient receptor potential cation channel subfamily V member 1 (TRPV1) have been reported to be associated with dry eye (DE) disease, whether they interact and their regulatory roles in diabetic DE disease are unknown. Diabetic DE model mice were generated by streptozotocin induction and assessed by corneal fluorescein staining, tear ferning (TF) tests, phenol red thread tests, hematoxylin and eosin staining of corneal sections and periodic acid Schiff staining of conjunctival sections. Cell proliferation was measured by CCK8 assay. Western blotting was performed to measure protein expression. Primary mouse corneal epithelial cells (MCECs) were cultured after enzymatic digestion. Immunofluorescence staining of MCECs and frozen corneal sections was conducted to assess protein expression and colocalization. Coimmunoprecipitation was performed to detect protein‑protein interactions. It was found that, compared with control mice, diabetic DE mice exhibited increased corneal epithelial defects, reduced tear production, poorer TF pattern grades and impaired corneal and conjunctival tissues. and experiments showed that hyperglycemia impaired cell proliferation, accompanied by decreased levels of the MUC1 extracellular domain (MUC1‑ND) and TRPV1. Additionally, it was found that capsazepine (a TRPV1 antagonist) inhibited the proliferation of MCECs. Notably, MUC1‑ND was shown to interact with the TRPV1 protein in the control group but not in the diabetic DE group. It was also found that the AKT signaling pathway was attenuated in the diabetic DE mice and downstream of TRPV1. MUC1‑ND interacted with TRPV1, partly activating the AKT signaling pathway to promote MCEC proliferation. The present study found that the interaction of MUC1‑ND with TRPV1 promotes MCEC proliferation by partly activating the AKT signaling pathway, providing new insight into the pathogenesis of corneal epithelial dysfunction in diabetic DE disease.
尽管黏蛋白 1（MUC1）和瞬时受体电位阳离子通道亚家族 V 成员 1（TRPV1）已被报道与干眼症（DE）疾病有关，但它们是否相互作用以及它们在糖尿病 DE 疾病中的调节作用尚不清楚。通过链脲佐菌素诱导生成糖尿病 DE 模型小鼠，并通过角膜荧光素染色、泪液蕨状（TF）试验、酚红线试验、角膜切片苏木精和伊红染色以及结膜切片过碘酸希夫染色进行评估。通过 CCK8 测定法测量细胞增殖。通过 Western blot 测定法测量蛋白质表达。通过酶消化培养原代小鼠角膜上皮细胞（MCEC）。通过免疫荧光染色 MCEC 和冷冻角膜切片评估蛋白质表达和共定位。进行共免疫沉淀以检测蛋白质-蛋白质相互作用。结果发现，与对照小鼠相比，糖尿病 DE 小鼠表现出增加的角膜上皮缺陷、减少的泪液产生、较差的 TF 模式等级以及受损的角膜和结膜组织。体外和体内实验表明，高血糖损害细胞增殖，同时伴有 MUC1 细胞外结构域（MUC1-ND）和 TRPV1 水平降低。此外，还发现辣椒素（TRPV1 拮抗剂）抑制 MCEC 的增殖。值得注意的是，在对照组中发现 MUC1-ND 与 TRPV1 蛋白相互作用，但在糖尿病 DE 组中没有发现。还发现糖尿病 DE 小鼠中的 AKT 信号通路减弱且 TRPV1 的下游也减弱。MUC1-ND 与 TRPV1 相互作用，部分激活 AKT 信号通路以促进 MCEC 增殖。本研究发现，MUC1-ND 与 TRPV1 的相互作用通过部分激活 AKT 信号通路促进 MCEC 增殖，为糖尿病 DE 疾病中角膜上皮功能障碍的发病机制提供了新的见解。
