OTUD1 delays wound healing by regulating endothelial function and angiogenesis in diabetic mice.

INTRODUCTION: Diabetic non-healing wounds represent a major complication of diabetes, primarily due to impaired angiogenesis. Ovarian tumor deubiquitinase 1 (OTUD1), a deubiquitinase, has been implicated in vascular pathophysiology; however, its role in endothelial dysfunction and angiogenesis during diabetic wound healing is still poorly understood. OBJECTIVES: This study explores whether OTUD1 influences angiogenesis and its underlying mechanisms. METHODS: We developed OTUD1 knockout mice and induced type 1 and type 2 diabetes mellitus (T1DM and T2DM) by administering streptozotocin (STZ) alone or in combination with a high-fat diet (HFD), respectively. Human umbilical vein endothelial cells (HUVECs) incubated with high glucose and palmitic acid (HG + PA) were utilized to imitate hyperglycemia-induced endothelial dysfunction in vitro. Mass spectrometry combined with immunoprecipitation analysis was used to analyze the interacting proteins of OTUD1. Moreover, we developed endothelial-specific OTUD1 knockdown db/db mice using an adeno-associated virus serotype 2/BI30 (AAV2/BI30) vector. RESULTS: Increased OTUD1 expressions were observed both in diabetic wound tissues and in HUVECs treated with HG + PA. OTUD1 deficiency promoted angiogenesis and fibrosis in wound tissues of T1DM and T2DM mice and alleviated HG + PA-induced endothelial migration inhibition, tube formation impairment, and oxidative stress in HUVECs. Mechanistically, OTUD1 directly interacted with β-catenin, reducing its K63-linked ubiquitination at residues K496, K508, and K625 via its catalytic site C320. This modification facilitated β-catenin phosphorylation, restricted its nuclear translocation, and downregulated the expression of angiogenesis-related factors. Finally, pharmacological inhibition of β-catenin reversed the improvement of delayed wound healing induced by OTUD1 knockdown in db/db mice. CONCLUSION: These findings elucidate the OTUD1-β-catenin pathway's role in endothelial dysfunction-associated angiogenesis and suggest OTUD1 as a promising therapeutic target for diabetic non-healing wounds.