KuJiang GanLuoYin Alleviates Hypertensive Vascular Injury and Modulates FMO2/FTO/m6A Signaling

Background: Hypertension-induced vascular injury involves endothelial dysfunction, inflammation, and oxidative stress, leading to vascular remodeling and cardiovascular complications. Flavin-containing monooxygenase 2 (FMO2) has been implicated in redox regulation, but its role in hypertensive vascular injury remains unclear. This study investigated whether KuJiang GanLuoYin (KJGLY) protects against hypertensive vascular injury and whether FMO2-associated Fat mass and obesity-associated protein (FTO)/N6-methyladenosine (m6A) signaling is involved. Methods: Spontaneously hypertensive rats (SHRs) were treated with KJGLY for eight weeks. Blood pressure, vascular remodeling, inflammation, oxidative stress, and global m6A RNA methylation were assessed. Integrated metabolomic and proteomic analyses were performed to identify treatment-associated molecular alterations and candidate proteins. AAV9-mediated FMO2 knockdown in SHRs and gain- and loss-of-function approaches in angiotensin II (Ang II)-stimulated human umbilical vein endothelial cells were used to examine the functional involvement of FMO2. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based chemical profiling and High-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) quantification were performed to characterize the major constituents of KJGLY. Results: KJGLY significantly reduced blood pressure and alleviated vascular remodeling in SHRs. Metabolomic and proteomic analyses revealed treatment-associated alterations in inflammatory and lipid metabolic pathways and identified FMO2 as a treatment-responsive candidate. KJGLY restored FMO2 expression, reduced FTO abundance and NF-κB activation, increased global m6A levels, and attenuated inflammatory and oxidative stress responses in hypertensive aortas. Conversely, AAV9-mediated FMO2 knockdown aggravated vascular injury, enhanced inflammation and oxidative stress, reduced global m6A levels, and increased NF-κB activation. Co-immunoprecipitation showed an association between FMO2 and FTO, and MeRIP-qPCR indicated that FMO2 manipulation altered m6A enrichment of VCAM-1 mRNA. In Ang II-stimulated endothelial cells, linarin, the most abundant quantified constituent of KJGLY, partially recapitulated the cellular effects of KJGLY, including restoration of FMO2/FTO-associated signaling and attenuation of inflammatory activation. Conclusions: These findings support a functional role for FMO2 in hypertensive vascular injury and suggest that FMO2-associated modulation of FTO/m6A signaling may contribute to the vascular protective effects of KJGLY. Linarin recapitulated key protective effects in vitro, although its in vivo contribution to the formula remains to be determined.