Jiuyao Zhou

Introduction: The calcium-sensing receptor (CaSR), a G protein-coupled receptor (GPCR), plays a critical role in kidney injury by promoting inflammation and apoptosis when activated. Whether Wulingsan (WLS), a traditional Chinese herbal formula used for kidney disorders, exerts its protective effects against acute kidney injury (AKI) via modulation of the CaSR pathway remains unclear. Methods: WLS’s chemical profile was characterized by ultra-high performance liquid chromatography coupled with Q-Exactive mass spectrometry (UHPLC-QE-MS). C57BL/6J mice were divided into Control, cisplatin (CP)-induced AKI, WLS (2.34/4.68/9.36 g/kg), and CaSR inhibitor NPS2143 (4.5 mg/kg) groups. Mice were pretreated with WLS/NPS2143 before CP injection (20 mg/kg, i. p.). Renal function, histopathology, inflammation, oxidative stress, and apoptosis were evaluated. Cisplatin-induced mouse renal tubular epithelial cells (mRTECs) were treated with WLS-containing serum (5%–10%) for in vitro validation. Molecular docking predicted the binding affinity of WLS components to CaSR. Results: UHPLC-QE-MS identified 15 major WLS components, with 13 binding to CaSR (Polyporusterone E: binding energy of −10.4 kcal/mol). WLS pretreatment significantly improved renal function (reduced serum creatinine (SCr)/blood urea nitrogen (BUN)), attenuated tubular injury, suppressed inflammation (downregulated monocyte chemoattractant protein-1 (MCP-1)/tumor necrosis factor-α (TNF-α)/interleukin-1β (IL-1β)), alleviated oxidative stress (restored glutathione (GSH)/superoxide dismutase (SOD), reduced malondialdehyde (MDA)), and inhibited apoptosis (decreased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, modulated Bcl-2-associated X protein (Bax)/B-cell lymphoma-2 (Bcl-2) ratio, downregulated cleaved Caspase 3). Mechanistically, WLS inhibited renal CaSR/calmodulin-dependent protein kinase β (CaMKKβ)/adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) pathway activation (reduced CaSR/CaMKKβ/p-AMPK expression). In vitro , WLS-containing serum reduced cisplatin-induced reactive oxygen species (ROS) production, intracellular Ca ²⁺ overload, and apoptosis in mRTECs, effects reversed by the CaSR agonist cinacalcet. Conclusion: This study demonstrates that WLS protects against CP-induced kidney injury and inhibits apoptosis in renal tubular epithelial cells in association with the CaSR/CaMKKβ/AMPK pathway.

Renal fibrosis is a common pathological process in chronic kidney disease (CKD), which is mainly characterized by glomerulosclerosis and tubulointerstitial fibrosis. The formation and development of renal fibrosis are stimulated by pro‐inflammatory as well as pro‐fibrosis factors released by inflammatory cells. Wuling San is an ancient Chinese classical formula for urination‐promoting and dampness‐draining, which can regulate the metabolism of water and fluid and has exerted therapeutic effects on various chronic kidney diseases by reducing oedema, inflammation, and improving glomerulosclerosis and renal interstitial fibrosis. However, further study is still needed to explore the mechanism. Based on the research analysis with the help of CiteSpace, the following three directions were the possible mechanisms in improving renal fibrosis: inhibiting the conversion of renal cells to myofibroblasts; regulating amino acid, lipid and energy metabolism and reducing extracellular matrix (ECM) deposition; and regulating the RhoA/ROCK pathway, the downstream of G protein‐coupled receptor (GPCR). This review aims to summarize the mechanism of action of Wuling San in the treatment of CKD from the perspective of antifibrosis, which can help to explore the new ideas and directions of Wuling San in the treatment of renal diseases.

Introduction: The pathogenesis of renal fibrosis is related to blood stasis, and the method of promoting blood circulation and removing blood stasis is often used as the treatment principle. Danshen injection (DSI) is a commonly used drug for promoting blood circulation and removing blood stasis in clinic. However, whether DSI slows the progression of renal fibrosis or the potential mechanism is uncertain.Methods: We investigated renal fibrosis models using UUO mice and TGF-β stimulation in HK-2 cells.Results: Our findings revealed that DSI or Fer-1 alleviated kidney injury by ameliorating renal morphology injury and pathological injury in vivo. Besides, DSI or Fer-1 inhibited renal fibrosis in vivo and in TGF-β-induced HK-2 cells. Furthermore, ferroptosis was lessened under DSI or Fer-1 treatment. More importantly, the DSI active ingredients (danshensu, salvianolic acid B, protocatechuic aldehyde, caffeic acid and tanshinone IIA) could bind to SIRT1. The protein levels of SIRT1 and GPX4 were downregulated accompanied by the incremental concentrations of TGF-β or Erastin, which were repaired by DSI or Fer-1 intervention. However, the inhibition of ferroptosis and renal fibrosis owing to DSI were reversed by SIRT1 inhibitor EX527.Conclusion: Taken together, our results indicated that DSI could protect against ferroptosis to attenuate renal fibrosis by activating the SIRT1/GPX4 pathway. It is expected to be a potential agent to treat renal fibrosis.