Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, 40292, United States.
Department of Ophthalmology and Visual Sciences, Ohio State University College of Medicine, Columbus, OH, 43210, United States.
Biochem Biophys Res Commun. 2023 Jul 30;667:127-131. doi: 10.1016/j.bbrc.2023.05.040. Epub 2023 May 14.
Retinal pigment epithelial (RPE) cells contribute to several clinical conditions resulting in retinal fibrotic scars. Myofibroblast trans-differentiation of RPE cells is a critical step in the process of retinal fibrosis. In this study, we investigated the effects of N-oleoyl dopamine (OLDA), a newer endocannabinoid with a structure distinct from classic endocannabinoids, on TGF-β2-induced myofibroblast trans-differentiation of porcine RPE cells. Using an in vitro collagen matrix contraction assay, OLDA was found to inhibit TGF-β2 induced contraction of collagen matrices by porcine RPE cells. This effect was concentration-dependent, with significant inhibition of contraction observed at 3 μM and 10 μM. OLDA did not affect the proliferation of porcine RPE cells. Immunocytochemistry showed that at 3 μM, OLDA decreased incorporation of α-SMA in the stress fibers of TGF-β2-treated RPE cells. In addition, western blot analysis showed that 3 μM OLDA significantly downregulated TGF-β2-induced α-SMA protein expression. Taken together these results demonstrate that OLDA inhibits TGF-β induced myofibroblast trans-differentiation of RPE cells. It has been established that classic endocannabinoid such as anandamide, by activating the CB1 cannabinoid receptor, promote fibrosis in multiple organ systems. In contrast, this study demonstrates that OLDA, an endocannabinoid with a chemical structure distinct from classic endocannabinoids, inhibits myofibroblast trans-differentiation, an important step in fibrosis. Unlike classic endocannabinoids, OLDA has weak affinity for the CB1 receptor. Instead, OLDA acts on non-classic cannabinoid receptors such as GPR119, GPR6, and TRPV1. Therefore, our study indicates that the newer endocannabinoid OLDA and its non-classic cannabinoid receptors could potentially be novel therapeutic targets for treating ocular diseases involving retinal fibrosis and fibrotic pathologies in other organ systems.
视网膜色素上皮 (RPE) 细胞参与多种导致视网膜纤维性瘢痕的临床病症。RPE 细胞的肌成纤维细胞转分化是视网膜纤维化过程中的关键步骤。在这项研究中，我们研究了 N-油酰基多巴胺 (OLDA)（一种与经典内源性大麻素结构不同的新型内源性大麻素）对 TGF-β2 诱导的猪 RPE 细胞肌成纤维细胞转分化的影响。通过体外胶原基质收缩试验发现，OLDA 可抑制 TGF-β2 诱导的猪 RPE 细胞对胶原基质的收缩。这种作用呈浓度依赖性，在 3μM 和 10μM 时观察到显著的收缩抑制作用。OLDA 不影响猪 RPE 细胞的增殖。免疫细胞化学显示，在 3μM 时，OLDA 减少了 TGF-β2 处理的 RPE 细胞中应激纤维中 α-SMA 的掺入。此外，Western blot 分析显示，3μM OLDA 显著下调 TGF-β2 诱导的 α-SMA 蛋白表达。这些结果表明，OLDA 抑制 TGF-β2 诱导的 RPE 细胞肌成纤维细胞转分化。已经证实，经典内源性大麻素，如大麻素，通过激活 CB1 大麻素受体，促进多个器官系统的纤维化。相比之下，本研究表明，OLDA，一种与经典内源性大麻素化学结构不同的内源性大麻素，抑制肌成纤维细胞转分化，这是纤维化的一个重要步骤。与经典内源性大麻素不同，OLDA 对 CB1 受体的亲和力较弱。相反，OLDA 作用于非经典大麻素受体，如 GPR119、GPR6 和 TRPV1。因此，我们的研究表明，新型内源性大麻素 OLDA 及其非经典大麻素受体可能成为治疗涉及视网膜纤维化和其他器官系统纤维化病理的眼部疾病的新的治疗靶点。
