The present study systematically investigated the impact of angiotensin‑converting enzyme 2‑knockout (ACE2KO) on hepatic metabolic homeostasis and its molecular mechanisms using integrated transcriptomic, proteomic and metabolomic profiling. ACE2KO exacerbated hepatic lipid accumulation, as evidenced by elevated total cholesterol and triglyceride levels, while disrupting the renin‑angiotensin system equilibrium via increased angiotensin II levels and reduced angiotensin‑(1‑7) levels. Histopathological analysis revealed hepatocyte edema, vacuolar degeneration and inflammatory infiltration in the ACE2KO mice. Multi‑omics integration revealed systemic metabolic dysregulation. Transcriptomics identified 1,004 differentially expressed genes, including lipid metabolism regulators (Scd1 and Fabp1) and circadian rhythm modulators (Arntl and Cry1), proteomics identified 191 differentially expressed proteins associated with interferon signaling activation (Oas1a and Rsad2) and lipid synthesis suppression (Scd1 and Fasn), and metabolomics highlighted 193 differentially expressed metabolites indicative of bile acid dysregulation, glutathione redox imbalance and amino acid metabolism anomalies. Cross‑omics analysis indicated that ACE2 is a key regulator of metabolic homeostasis. Its absence causes systematic metabolic disorders, including lipid metabolism disorder, amino acid metabolic imbalance and detoxification dysfunction. These findings comprehensively delineated the multifaceted role of ACE2 in hepatic metabolic homeostasis, and provided mechanistic insights into and therapeutic targets for ACE2‑associated liver diseases.
Keywords: angiotensin‑converting enzyme 2; gene knockout; liver metabolic dysregulation; metabolomics; proteomics; transcriptomics.