Circular RNA <em>ZBTB46</em> Attenuates Apoptosis and Oxidative Stress in Lipopolysaccharide-Injured Human Endothelial Cells by Modulating ERBB2-AKT Signaling

Circular RNAs are emerging regulators of stress responses, yet their roles in endothelial injury that leads to sepsis-related acute kidney injury remain incompletely defined. We hypothesized that the circular RNA ZBTB46 (circZBTB46) confers endothelial protection by engaging ERBB2-AKT signaling. Using a cell-based model in which human umbilical vein endothelial cells were challenged with lipopolysaccharide, we quantified circZBTB46 expression and tested the effects of its forced expression on survival, apoptosis, inflammatory mediators, and redox homeostasis. Cell viability assays and flow cytometry assessed survival and apoptosis. Enzyme-linked immunosorbent assays measured interleukin-6, tumor necrosis factor-α, and interleukin-1β, while reactive oxygen species, malondialdehyde, superoxide dismutase, and catalase were evaluated as indices of oxidative injury and antioxidant capacity. To define the mechanism, we performed transcriptome profiling with gene set enrichment analysis, confirmed pathway proteins by Western blotting, and assessed the necessity using the ERBB2 inhibitor AG-825. Lipopolysaccharide suppressed circZBTB46. CircZBTB46 overexpression increased viability, lowered apoptosis, reduced pro-inflammatory cytokines and reactive oxygen species, decreased malondialdehyde, and raised superoxide dismutase and catalase activities. Transcriptomic and protein analyses supported activation of the ERBB2-AKT axis, and pharmacologic ERBB2 blockade blunted cytoprotection and reversed gains in redox balance. These findings identify circZBTB46 as an endogenous brake on lipopolysaccharide-induced endothelial damage through ERBB2-AKT signaling and nominate circZBTB46 as a mechanistic node and potential therapeutic target for sepsis-related acute kidney injury.