HHcy promotes hypertension by activating ferroptosis via suppression of the renal H₂S-SLC7A11/GPX4 axis.

Elevated homocysteine (Hcy) is an independent risk factor for hypertension, and kidney is an important organ for Hcy metabolism and blood pressure regulation, and its damage is closely related to the process of hypertension. Recent evidence suggests that ferroptosis, an oxidative stress-related form of cell death, contributes significantly to hypertensive organ damage. However, whether Hcy aggravates renal injury in H-type hypertension by destroying renal hydrogen sulfide (H2S) metabolism and driving ferroptosis is still lack of direct evidence. In this study, the H-type hypertensive rat model induced by high methionine diet combined with HK-2 cell model was studied. We observed a significant increase in blood pressure and plasma Hcy in the Hcy group, accompanied by renal dysfunction and renal tubular injury. Specifically, in the renal tissue of Hcy group rats, the levels of KIM-1, Fe2+ and malondialdehyde (MDA) were increased, glutathione/glutathione disulfide (GSH/GSSG) ratio decreased, SLC7A11 expression was down-regulated, and GPX4 activity was inhibited. Concurrently, H2S levels and cystathionine-beta-synthase (CBS) activity were decreased. In vitro experiments using HK-2 cells confirmed that Hcy could down-regulate the expression of CBS, cystathionine-gamma-lyase (CSE), SLC7A11, GPX4 and GSH/GSSG ratio, and up-regulate MDA and reactive oxygen species (ROS) levels. Treatment with H2S donor (NaHS) or ferroptosis inhibitors (Ferrostatin-1, Fer-1) could rescue these changes. Collectively, our results demonstrate that high Hcy promotes hypertension by suppressing endogenous H2S generation, downregulating the SLC7A11/GPX4 signaling axis, and inducing ferroptosis. These findings reveal a new mechanism by which Hcy aggravates hypertension by inhibiting H2S synthesis and inducing ferroptosis.