Vascular smooth muscle cells (VSMCs) are the most abundant cell type in blood vessels, participating in cardiovascular diseases in various ways, among which their transformation into macrophage-like cells has become a research hotspot. In this study, rats were infused with aldosterone for 12 weeks, and VSMCs stimulated with aldosterone in vitro were used to observe aortic injury and the role of VSMC transformation. Vascular changes were detected via small animal ultrasound and H&E staining. Moreover, immunohistochemistry, immunofluorescence, Western blot, and flow cytometry were used to verify that the transformation of VSMCs into macrophage-like cells is regulated by mineralocorticoid receptor (MR) activation and macrophage colony-stimulating factor (M-CSF) and its receptor. Rat vasculature and in vitro cellular experiments revealed that VSMCs transformed into macrophage-like cells and secreted inflammatory factors such as interleukin-1β (IL-1β) and monocyte chemoattractant protein-1 (MCP-1), thereby exacerbating inflammatory vascular lesions, which was inhibited by the MR antagonist esaxerenone. These results reveal that increased levels of aldosterone activate MR, leading to the secretion of M-CSF by VSMCs. This further promotes the transformation of VSMCs into macrophage-like cells, which participate in inflammatory vascular lesions. Therefore, inhibiting the formation of macrophage-like cells can effectively reduce inflammatory vascular lesions.

Background: Vascular smooth muscle cell (VSMC) injury caused by the inflammatory response plays a key role in cardiovascular disease (CVD), and the vasoprotective effects of mineralocorticoid receptor blockers (MRBs) support the role of mineralocorticoid receptor (MR) activation. Methods: C57BL/6 mice and VSMCs isolated from rats were treated with aldosterone and esaxerenone. Caspase-1, GSDMD-N, IL-1β, and NR3C2 expression and DNA damage in aortic VSMCs were detected using immunohistochemistry, Western blotting, and TUNEL staining. Mitochondrial changes were detected by transmission electron microscopy (TEM). Reactive oxygen species (ROS), MitoTracker, JC-I, mitochondrial respiratory chain complexes I–V, and NR3C2 were detected using immunofluorescence and flow cytometry. Pyroptosis was detected with scanning electron microscopy (SEM). Results: After aldosterone treatment, the number of TUNEL-positive cells increased significantly, and the expression of caspase-1, GSDMD-N, and IL-1β increased. TEM revealed mitochondrial damage, and SEM revealed specific pyroptotic changes, such as cell membrane pore changes and cytoplasmic extravasation. Increased ROS levels and nuclear translocation of NR3C2 were also observed. These pyroptosis-related changes were reversed by esaxerenone. Conclusions: Aldosterone activates the MR and mediates mitochondrial damage, thereby inducing pyroptosis in VSMCs via the NLRP3/caspase-1 pathway. Esaxerenone inhibits MR activation and reduces mitochondrial damage and oxidative stress, thereby inhibiting pyroptosis.

To investigate the effect of mineralocorticoid receptor (MR) blockade esaxerenone on renal macrophage proliferation in db/db mice and its potential role in the progression of diabetic kidney disease (DKD). Eight-week-old db/db mice were administered esaxerenone at a dose of 1 mg/kg/day for six weeks. The origin of macrophages (resident versus recruited) and their phenotypic subtypes (M1 vs. M2) were evaluated using molecular markers, including F4/80, Ki-67, Ly6C, iNOS, and CD206. Immunohistochemistry, flow cytometry, and single-cell RNA sequencing were utilized to evaluate these parameters. The inhibitory effects of esaxerenone and the TGF-β1 inhibitor LY2109761 on the proliferation of bone marrow-derived macrophages (BMDMs) under high-glucose conditions were examined in vitro. Marked increases in macrophage infiltration and proliferation were observed in the kidneys of db/db mice. Both recruited and resident macrophages exhibited significant proliferative activity, with recruited macrophages predominantly adopting an M1 phenotype and resident macrophages primarily exhibiting an M2 phenotype. Proliferating macrophages displayed enhanced pro-inflammatory and pro-fibrotic responses compared to non-proliferating counterparts. In vivo, esaxerenone treatment significantly suppressed macrophage proliferation. In vitro studies demonstrated that high glucose activated MR, upregulated TGF-β1 expression, and subsequently promoted BMDMs proliferation, particularly within the M1 subtype. TGF-β1 alone also induced BMDMs proliferation, an effect attenuated by LY2109761. Esaxerenone inhibits renal macrophage proliferation mediated by high glucose-induced activation of MR and downstream TGF-β1 signaling pathways, thereby mitigating inflammatory and fibrotic damage. These findings suggest that MR blockade may directly target macrophage proliferation and inflammation in DKD.

Fibroblasts and lymphangiogenesis promote renal fibrosis. However, whether fibroblasts promote renal fibrosis via lymphangiogenesis has not yet been fully elucidated. This study set out to clarify whether aldosterone induces fibroblast transdifferentiation into lymphatic endothelial-like cells, thus promoting lymphangiogenesis and renal fibrosis. In vivo, twenty-four male Wistar rats were randomized into Sham, ALD (6-week aldosterone infusion), and ALD + ESA (aldosterone infusion with esaxerenone co-treatment) groups. In vitro, primary rat renal interstitial fibroblasts (RKFs) were used. Immunohistochemistry and Western blot were used to detect lymphatic endothelial and fibroblast marker expression in kidneys from aldosterone-infused rats and RKFs. Their co-expression was determined by flow cytometry and immunofluorescence co-staining. Mineralocorticoid receptor (MR) activation and related signaling pathways were also analyzed by Western blot, immunohistochemistry, and flow cytometry. Additionally, RKF migration and tube formation were examined to investigate the role of aldosterone-induced fibroblast-to-lymphatic endothelial-like transdifferentiation in renal fibrosis. Our data suggest that aldosterone activates the MR and induces the transdifferentiation of fibroblasts into lymphatic endothelial-like cells via the MR/VEGFC/VEGFR-3 pathway, thereby promoting lymphangiogenesis. In addition, the administration of esaxerenone (a mineralocorticoid receptor blocker, MRB) to rats significantly suppresses this transdifferentiation and alleviates fibrosis.

Renal fibrosis is a multifaceted pathological process driven by cellular interactions, with fibroblasts and macrophages serving as central regulators. Fibroblasts activate into matrix-producing myofibroblasts, directly contributing to fibrogenesis and disease progression. Macrophages, characterized by pronounced heterogeneity, dynamically modulate the balance between tissue injury and repair, thereby critically influencing disease outcomes. The crosstalk between these two cell types operates through diverse signaling pathways, extracellular vesicle-mediated communication, and metabolic reprogramming, forming an intricate regulatory network that exerts stage-specific effects during renal injury. Recent insights into fibroblast activation, macrophage polarization, and their intercellular interplay have provided potential therapeutic avenues for delaying kidney fibrosis, offering renewed promise for clinical translation.