Background: Atherosclerosis preferentially develops at arterial regions exposed to low shear stress (LSS), highlighting the critical role of local hemodynamic forces in disease initiation and progression. Emerging evidence indicates that endothelial lipid metabolism is a key determinant of vascular homeostasis; however, whether LSS directly regulates endothelial lipid droplets’ (LDs) dynamics remains unclear. In particular, the mechano-transduction pathways linking shear stress to lysosome-mediated lipid processing within the endothelium have yet to be defined. Methods: Complementary in vitro flow systems and in vivo atheroprone models were employed to examine the effects of LSS on endothelial lipid metabolism. Endothelial LDs accumulation, lysosome-dependent lipophagy, and atherosclerotic lesion development were systematically assessed under LSS conditions. Mechanistically, molecular profiling and rapamycin-mediated functional rescue were conducted to delineate the role of the KLF4/TFEB/ATP1A1 signaling axis in LSS-induced impairment of lysosome-dependent lipophagy. Results: We found that LSS induced pathological accumulation of LDs in vascular endothelial cells, accompanied by a marked suppression of lysosome-dependent lipophagy. Elucidation of the mechanism showed that LSS downregulated the shear-responsive transcription factor KLF4, resulting in aberrant phosphorylation of transcription factor EB (TFEB) and impaired TFEB nuclear translocation. Consequently, the TFEB transcriptional program governing lysosomal function was disrupted, including reduced expression of the TFEB target ATP1A1, leading to defective lysosomal acidification and blockade of lipid autophagic flux. Restoration of the KLF4/TFEB/ATP1A1 axis reactivated lipophagy, alleviated endothelial lipid burden, and significantly attenuated atherosclerotic lesion development. Conclusions: Our findings demonstrate that disruption of the KLF4/TFEB/ATP1A1 signaling pathway mediates LSS-induced impairment of endothelial lipophagy, thereby driving pathological LDs accumulation. This highlights the potential of restoring this axis as a therapeutic strategy to attenuate atherosclerotic progression.

Pathological cardiac remodeling is a significant contributor to heart failure and mortality. Studies have demonstrated that extracellular signal regulated kinase 3 (ERK3) in cardiac fibroblasts aggravates pressure overload-evoked pathological cardiac remodeling via mitogen activated protein kinase-activated protein kinase-5 (MK5). However, myocardial ERK3 does not activate MK5, thus the role of myocardial ERK3 remains unclear. Through in vivo and in vitro experiments, we revealed that myocardial ERK3 expression increases under pressure overload and the protein accumulates significantly in the nucleus. Using cardiomyocyte-specific Erk3 -deficient mice, neonatal rat cardiomyocytes and adult mouse cardiomyocytes, we found that cardiomyocyte-specific Erk3 deficiency ameliorated pressure overload-induced pathological cardiac remodeling in vivo. Co-immunoprecipitation, mass spectrometry, and single nucleus RNA sequencing were used to analyse for the nuclear translocation and downstream signaling mechanisms of ERK3. Specifically, pressure overload enhances the binding of Aly/REF export factor (ALY) to ERK3, resulting in the truncation of the ERK3 C-terminal and its subsequent nuclear translocation to activate the thioredoxin-interacting protein (TXNIP)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3) pathway through the expression of the splicing factor proline and glutamine rich (SFPQ). To screen for targeted drugs, we conducted a virtual screening and identified estrone sulfate as an inhibitor of ALY to counteract hypertrophic effects. Collectively, our findings indicate that estrone sulfate functions as a novel inhibitor of the ALY-ERK3 signaling pathway, potentially serving as a promising therapeutic candidate for the management of pathological cardiac remodeling.

Endothelial dysfunction persisting after glucose normalization, termed metabolic memory, constitutes a primary driver of diabetic vascular complications, y