Peptide IRW upregulates ACE2 in spontaneously hypertensive rats via dopamine/D1R signaling pathway

INTRODUCTION: The bioactive peptide IRW lowers blood pressure in spontaneously hypertensive rats (SHRs) by upregulating angiotensin-converting enzyme 2 (ACE2), but the underlying mechanisms remain unclear. OBJECTIVES: This study aimed to elucidate the mechanisms underlying IRW-mediated ACE2 upregulation through integrated transcriptomic and metabolomic analyses. METHODS: Mesenteric arteries from IRW-treated SHRs underwent transcriptomic and metabolomic analyses. Weighted gene co-expression network analysis (WGCNA) and transcription factor prediction were performed to identify ACE2-associated regulators. Subsequent validation was conducted both in vitro with EA.hy926 endothelial cells and in vivo via receptor blocker infusion in SHRs. RESULTS: WGCNA of transcriptomic data identified 651 genes co-expressed with ACE2, including 17 predicted transcription factors, notably nuclear receptor 4A1 (Nr4a1). Metabolomic analysis revealed a significant increase in dopamine after IRW treatment, and its abundance correlated with ACE2 expression. Ingenuity pathway analysis indicated that dopamine may activate Nr4a1 via the dopamine D1 receptor (D1R). In vitro, dopamine (1 μM) upregulated protein levels of ACE2 and Nr4a1, effects blocked by the D1R antagonist SCH23390 (10 μM). Additionally, Nr4a1 knockdown reduced dopamine-induced ACE2 upregulation. In SHRs, D1R blockade abolished IRW's antihypertensive effects and ACE2 upregulation. CONCLUSION: IRW-driven ACE2 upregulation in vivo relies on the dopamine/D1R signaling pathway, highlighting the therapeutic potential of this pathway for ACE2-related conditions.