Abstract Background Cardiovascular diseases in type 2 diabetes (T2D), including both macro- and microvascular complications, remain a leading cause of mortality worldwide. Despite their high prevalence, effective therapeutic options are currently limited. BUD13, a nuclear RNA-binding protein, plays a crucial role in RNA splicing. Emerging evidence suggests its involvement in the pathogenesis of metabolic syndrome; however, the role of BUD13 in cardiovascular disease is unclear. Purpose This study investigates the contribution of BUD13 to T2D-associated cardiovascular complications. Methods BUD13 expression was assessed in the aortae (macrovasculature) and in ocular vascular tissues (retina and choroid, microvasculature) from wild-type (WT) and db/db mice (a T2D model). Endothelium-dependent relaxation (EDR) was measured in (1) aortae exposed to high glucose (HG, 30 mM) for 18 h or (2) db/db aortae, both pre-treated with BUD13 siRNA using a wire myograph. The real-time cell migration together with the formation of reactive oxygen species (ROS) and nitric oxide (NO) were measured in human carotid arterial endothelial cells (HCtAEC), following exposure to HG compared to normal glucose (NG), with/without BUD13 siRNA (siBUD13). RNA sequencing, transcriptomic and proteome analysis were also performed. Results BUD13 was predominantly localised to the endothelium of the aorta (Fig. 1A–B) and ocular tissues (Fig. 1C–E), with elevated expression in db/db aortae and choroids compared with WT. siBUD13 significantly decreased BUD13 expression at the endothelial layer of db/db aortae (Fig. 1F). Notably, EDR was impaired in aortae exposed to HG (Fig. 1G) and in db/db aortae (Fig. 1H), an effect was significantly attenuated by siBUD13 in both cases. HCtAEC treated with HG showed both increased mRNA and protein BUD13 levels (Fig. 2A–B), which was ameliorated by siBUD13 (Fig. 2C). HCtAEC with HG also exhibited disrupted cell migration (Fig. 2D-E), increased ROS formation (Fig. 2F-G) and reduced NO production (Fig. 2H-I), all of which were normalized by siBUD13. Transcriptomic analysis revealed differentially expressed genes in HG-treated HCtAEC following BUD13 silencing (Fig. 2J), with significant changes in key pro-inflammatory signalling pathways and hallmarks (Fig. 2K–L). Several candidates including MPO, TNFα, TGFα were confirmed to be downregulated and IL-17 to be upregulated by siBUD13 using proteomic analysis (Fig. 2M). A predictive interaction between SNIP1 (which modulates pro-inflammatory signalling) and BUD13 existed (Fig. 2N), which was supported by its downregulation after siBUD13 in HG HCtAEC (Fig. 2J) and its upregulation in db/db choroids (Fig. 2O–P). Conclusion Our findings highlight that endothelial BUD13 contributes to T2D-related vascular dysfunction through oxidative and inflammatory pathways. Targeting endothelial BUD13 may represent a potential therapeutical strategy for preventing both macrovascular and microvascular complications in T2D. Figure1ASGFor image description, please refer to the figure legend and surrounding text. Figure2ASGFor image description, please refer to the figure legend and surrounding text.
Garrido et al. (Fri,) studied this question.