Weng Zhiyan, Ren Xiaoyan, Lin Wanxin, Zheng Lifeng, Weng Renfu, Xie Liangxiao, Zhao Fengying, Yan Sunjie, Shen Ximei
Department of Endocrinology, the First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, 350005, China.
Department of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, 350005, China.
Cell Mol Life Sci. 2025 Aug 25;82(1):318. doi: 10.1007/s00018-025-05814-6.
Diabetic foot ulcers (DFUs) are a leading cause of disability and mortality, with endothelial dysfunction playing a key role in the development of non-healing ulcers. A primary driver of endothelial cell impairment in this context is endoplasmic reticulum (ER) stress, triggered by glycolipotoxicity, though the underlying mechanisms are not fully understood. In this study, we observed that diabetic mice displayed poor ulcer healing associated with reduced angiogenesis and downregulated Reticulocalbin 1 (RCN1) expression. Proteomic analysis in human umbilical vein endothelial cells (HUVECs) identified a strong link between RCN1 and the damaging effects of glycolipotoxicity on endothelial cell function, leading to impaired tubule formation, reduced migratory capacity, and increased apoptosis in endothelial cells. Mechanistic RNA sequencing analysis highlighted a significant role for RCN1 in regulating ER function. RCN1 overexpression alleviated ER stress by reducing Protein kinase R-like endoplasmic reticulum kinase (PERK) phosphorylation and C/EBP homologous protein (CHOP) expression, both induced by glycolipotoxicity or Thapsigargin (TG), while RCN1 silencing intensified these effects. Additionally, TRIM11-mediated ubiquitination, influenced by glycolipotoxicity, regulated RCN1 stability, specifically promoting angiogenesis through RCN1 modulation. RCN1 overexpression accelerated ulcer healing in diabetic mice by suppressing ER stress proteins and enhancing angiogenesis, whereas RCN1 inhibition further delayed ulcer healing. In human DFU samples, proteomic analysis revealed that low RCN1 levels were linked to disrupted ER functional proteins, with RCN1 serum levels decreasing as diabetes progressed to DFU. Following surgical debridement treatment, RCN1 levels increased in patients with improved DFU healing outcomes. These findings suggest that ER stress, initiated by RCN1 inhibition in response to glycolipotoxicity, leads to endothelial dysfunction and apoptosis, ultimately contributing to the non-healing of DFUs.
糖尿病足溃疡（DFU）是导致残疾和死亡的主要原因，内皮功能障碍在不愈合溃疡的发生发展中起关键作用。在这种情况下，内质网（ER）应激是内皮细胞损伤的主要驱动因素，由糖脂毒性引发，但其潜在机制尚未完全明确。在本研究中，我们观察到糖尿病小鼠溃疡愈合不良，伴有血管生成减少和网钙蛋白1（RCN1）表达下调。对人脐静脉内皮细胞（HUVEC）进行蛋白质组学分析发现，RCN1与糖脂毒性对内皮细胞功能的破坏作用之间存在紧密联系，导致内皮细胞小管形成受损、迁移能力降低和凋亡增加。机制性RNA测序分析突出了RCN1在调节内质网功能中的重要作用。RCN1过表达通过减少由糖脂毒性或毒胡萝卜素（TG）诱导的蛋白激酶R样内质网激酶（PERK）磷酸化和C/EBP同源蛋白（CHOP）表达来减轻内质网应激，而RCN1沉默则加剧了这些效应。此外，受糖脂毒性影响的TRIM11介导的泛素化调节RCN1稳定性，特别是通过调节RCN1促进血管生成。RCN1过表达通过抑制内质网应激蛋白和增强血管生成来加速糖尿病小鼠的溃疡愈合，而RCN1抑制则进一步延迟溃疡愈合。在人类DFU样本中，蛋白质组学分析显示低RCN1水平与内质网功能蛋白紊乱有关，随着糖尿病进展为DFU，RCN1血清水平降低。手术清创治疗后，DFU愈合结果改善的患者RCN1水平升高。这些发现表明，对糖脂毒性的反应中，RCN1抑制引发的内质网应激导致内皮功能障碍和凋亡，最终导致DFU不愈合。
