Exploring the mechanism of Yishen Huayu formula in intervening chronic kidney disease-mineral and bone disorder via the miR-340-5p/FGF-23/klotho signaling pathway.

BACKGROUND: Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a severe complication of chronic kidney disease characterized by dysregulation of the FGF-23/Klotho axis. MicroRNA-340-5p (miR-340-5p) participates in this signaling pathway. Nevertheless, its functional role in CKD-MBD, as well as the underlying mechanism by which Yishen Huayu Formula (YSHYF) intervenes in this disease, remains unclear. METHODS: A rat model of CKD-MBD was established using nephrectomy combined with adenine administration and a high-phosphate diet. Indicators of renal function, renal histopathology, renal fibrosis, bone microarchitecture and circulating bone-metabolic markers were evaluated. The expression of miR-340-5p, FGF-23 and Klotho in renal tissues was detected. A dual-luciferase reporter assay was performed to verify the targeting relationship between miR-340-5p and FGF-23. In-vivo knockdown of renal miR-340-5p was further applied to validate this regulatory mechanism. RESULTS: YSHYF ameliorated renal dysfunction, pathological injury and renal fibrosis in a dose-dependent manner. Improved bone microarchitecture and mineral metabolic disturbances were observed in YSHYF-treated CKD-MBD rats, which may occur secondarily to renal protection. YSHYF up-regulated the expression of renal miR-340-5p and Klotho while suppressing renal FGF-23. We confirmed that miR-340-5p directly targets FGF-23. Furthermore, knockdown of miR-340-5p partially reversed the renal-protective effect of YSHYF as well as its regulatory action on the renal FGF-23/Klotho axis. CONCLUSION: YSHYF alleviates renal injury, renal fibrosis and mineral-metabolism disturbances in CKD-MBD rats by up-regulating renal miR-340-5p to modulate the renal FGF-23/Klotho axis. The improvements in bone-related indicators observed in this study may be secondary to renal protection and the correction of mineral metabolism. These results provide experimental evidence for the application of YSHYF in the intervention of CKD-MBD.