Mafu Yishen Formula ameliorates membranous nephropathy by promotion of regulatory T cell differentiation: a...

Primary membranous nephropathy (PMN) is one of the main causes of nephrotic syndrome in adults, with edema as the primary symptom. The Mafu Yishen Formula (MFYS) is derived from a combination of classical prescriptions for treating edema diseases recorded in the Treatise on Cold Damage and Miscellaneous Diseases. While clinical efficacy of MFYS in treating PMN has been supported by evidence-based studies, its specific mechanisms remain unclear. This study aims to investigate the therapeutic effects and molecular mechanisms of MFYS in the treatment of membranous nephropathy, with a focus on whether MFYS promotes regulatory T cells (Treg) differentiation and modulates immune responses.

The passive Heymann nephritis (PHN) rat model was employed to simulate human PMN. Rats were treated with either low- or high-dose Mafu Yishen Formula (MFYS) or cyclosporine A (CsA) as a positive control. Urinary protein levels, serum biochemical parameters, renal pathological changes, and podocyte injury were evaluated. Immunofluorescence and flow cytometry were used to assess renal IgG deposition, B cell proliferation, and the proportion of Treg. Serum cytokine levels were measured using appropriate assays. The absorbed components of MFYS were identified via metabolomic analysis. Integrated strategies including network pharmacology, spleen transcriptomics, and proteomics were applied to identify key targets and signaling pathways. In vitro Treg polarization assays, supplemented with pathway inhibitors, were conducted to validate mechanistic findings. Molecular docking simulations were performed to explore interactions between active components of MFYS and potential target proteins.

MFYS significantly reduced urinary protein levels in PHN rats, improved biochemical indicators such as serum albumin and blood lipids. Pathological examination revealed that MFYS alleviated glomerular and podocyte injury, while also reducing intrarenal IgG deposition and suppressing splenic B cell activation. Serum tests indicated that MFYS increased levels of IL-2 and IL-10 while decreasing levels of IL-6 and IL-17. Notably, MFYS significantly increased the proportion of Tregs. Integrated network pharmacology and multi-omics analysis consistently revealed that MFYS upregulates the PI3K/AKT signaling pathway and enhances mitochondrial oxidative phosphorylation. Furthermore, MFYS intervention down regulated pSTAT3 expression while promoting PGC-1α expression. In vitro experiments further confirmed that MFYS directly promotes the differentiation of naïve T cells into Tregs, an effect that was counteracted by a PI3K/AKT pathway inhibitor. Molecular docking results suggested that some active components of MFYS can bind to AKT1.

MFYS modulates the immune response in PHN rats, reduces IgG deposition, and ameliorates renal and podocyte injury. It promotes Treg differentiation, regulates the cytokine network, and exerts multi-target effects on both inflammation and metabolism.