Abstract Body (Do not enter title and authors here): Background: Atherogenesis often develops in regions with disturbed blood flow (d-flow), involving increased ERK5 and p53 SUMOylation due to SENP2 T368 phosphorylation, leading to increased ERK5 and p53 SUMOylation, contributing to endothelial cell (EC) activation. Conversely, laminar flow (l-flow) induces SENP2 S344 phosphorylation, reducing ERK5 and p53 SUMOylation, thereby suppressing EC activation. The presence of senescent ECs in atherosclerotic plaques suggests that d-flow-induced EC senescence may contribute to atherogenesis, possibly due to metabolic changes. EC glycolysis is crucial for NO production and atheroprotection, however, it is inhibited by l-flow, indicating that l-flow protective effects extend beyond glycolysis.

Methods: In ECs from wild-type mice exposed to l-flow, the expression of DDIAS increases, regulated by SENP2 S344 phosphorylation. DDIAS interacts with ACLY, a key regulator of fatty acid metabolism and vascular function. We performed LC-MS and IC-MS analyses on ECs with DDIAS knocked down or control siRNA exposed to l-flow, using ¹³C₂-gucose or ¹³C₅-glutamine to trace metabolic changes. HMG-CoA, acetyl-CoA, and CoQ levels were measured using LC-MS and triple quadrupole LC-MS/MS.

Results: L-flow enhances glycolysis and glutaminolysis, significantly increasing TCA cycle intermediates through upregulated glutamine pathways. DDIAS expression and its interaction with ACLY are also increased by l-flow. Without DDIAS, the ACLY-mediated mevalonate pathway is inhibited, reducing l-flow-induced antioxidant mechanisms. Thus, the DDIAS-ACLY complex is crucial for the antioxidant response triggered by L-flow, which is essential for supporting angiogenesis after hindlimb ischemia. L-flow-induced increases in HMG-CoA and CoQ are inhibited by DDIAS depletion, highlighting the importance of DDIAS in maintaining the balance of metabolic and antioxidant pathways under L-flow. We are investigating the role of DDIAS-ACLY complex on l-flow-mediated upregulation of glycolysis and glutaminolysis.

Conclusion: DDIAS plays a key role in mediating l-flow atheroprotective effect by directly interacting with and activating ACLY, essential for the mevalonate pathway and subsequent HMG-CoA and CoQ biosynthesis. Under l-flow conditions, ECs preferentially utilize glutamine over glucose for TCA cycle intermediates, underscoring the importance of the DDIAS-ACLY complex in supporting EC protection and function through enhanced metabolic pathways.