Liuwei Dihuang Pills Inhibit Podocyte Injury and Alleviate IgA Nephropathy by Directly Altering Mesangial Cell-Derived Exosome Function and Secretion

Regulatory role of the mTOR signaling pathway in autophagy and mesangial proliferation in IgA nephropathy

OBJECTIVES

IgA nephropathy (IgAN) is the most common primary glomerular disease in China, but its pathogenesis remains unclear. This study aims to explore the regulatory role of the mammalian target of rapamycin (mTOR) signaling pathway in autophagy and mesangial proliferation during renal injury in IgA.

METHODS

The activity of mTOR and autophagy was evaluated in kidney samples from IgAN patients and in an IgAN mouse model induced by oral bovine serum albumin and carbon tetrachloride (CCl4) injection. mTOR inhibitors (rapamycin) and activators [bpV(phen)] were administered to the IgAN mouse model to observe the effects of mTOR on autophagy and renal lesions. In human mesangial cells treated with polymeric IgA1 (p-IgA1) and mTOR modulators, the expression and distribution of cell cycle proteins were assessed, along with the effects of mTOR on mesangial cell proliferation and autophagy.

RESULTS

Increased mTOR activity and decreased autophagy were observed in kidney tissues from IgAN patients and the mouse model, as evidenced by elevated phosphorylated mTOR (p-mTOR) levels and reduced LC3 expression. In the IgAN mouse model, rapamycin inhibited mTOR, restored autophagy, reduced mesangial IgA deposition, alleviated mesangial cell proliferation, and decreased proteinuria (all P<0.05). In contrast, bpV(phen) activated mTOR, further suppressed autophagy, exacerbated kidney damage, and increased proteinuria (all P<0.05). In vitro, p-IgA1 induced mesangial cell proliferation and inhibited autophagy, effects that were reversed by rapamycin and aggravated by bpV(phen) (all P<0.05). mTOR regulated mesangial cell proliferation by altering cell cycle distribution, with rapamycin inducing G1 phase arrest and bpV(phen) promoting cell cycle progression. Additionally, cyclinD1 expression in renal cortex was up-regulated in the IgAN mouse model, further increased by bpV(phen), and reduced by rapamycin (all P<0.05).

CONCLUSIONS

Inhibition of the mTOR signaling pathway enhances renal autophagy, reduces mesangial cell proliferation, and improves renal injury in IgAN.

Network pharmacology and molecular docking to elucidate the common mechanism of hydroxychloroquine treatment in lupus nephritis and IgA nephropathy

OBJECTIVE

Hydroxychloroquine (HCQ), characterized by a broad effect on immune regulation, has been widely used in the treatment of autoimmune glomerulonephritis such as lupus nephritis (LN) and immunoglobulin A nephropathy (IgAN). The current research investigates whether HCQ plays a role in the treatment of LN and IgAN through common mechanisms since the pathogenesis of both LN and IgAN is closely related to immune complex deposition, complement activation, and ultimately inflammation.

METHODS

Seventy-two common targets were obtained related to the common mechanism of HCQ treatment of LN and IgAN. Targets associated with LN and IgAN were collected based on DisGeNET, GeneCards, and OMIM databases. Possible HCQ targets were obtained from the PubChem database and PharmMapper databases. The overlapping targets of HCQ ingredients, IgAN, and LN were discovered via the Venn 2.1.0 online platform. Through the DAVID database, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted. Cytoscape (v3.9.1) was used to build a protein-protein interaction (PPI) network. Molecular docking was performed by using AutoDockTools 1.5.6 software and PyMol software to match the binding activity between HCQ and the 10 core targets.

RESULTS

The results showed that core targets (including MMP 2, PPARG, IL-2, MAPK14, MMP 9, and SRC), three signaling pathways (including the PI3K-Akt, AGE-RAGE, and MAPK), and cell differentiation (including Th1, Th2, and Th17) might be related to the body's immunity and inflammation. These results suggested that HCQ might act on targets and pathways involved in inflammation and immune regulation to exert a common effect on the treatment of LN and IgAN.

CONCLUSIONS

The current study provided new evidence for the protective mechanism and clinical utility of HCQ against LN and IgAN.

miR-664a-5p promotes experimental membranous nephropathy progression through HIPK2/Calpain1/GSα-mediated autophagy inhibition

We previously found that miR-664a-5p is specifically expressed in urinary exosomes of idiopathic membranous nephropathy (IMN) patients. Homeodomain-interacting protein kinase 2 (HIPK2), a nuclear serine/threonine kinase, plays an important role in nephropathy. But the function of these factors and their connection in MN are unclear. To investigate the function and mechanism of miR-664a-5p in MN, the miR-664a-5p expression in HK-2 cells, exosomes, podocytes and renal tissues were studied, as well as cell growth and apoptosis of these cells, the binding of miR-664a-5p to HIPK2 mRNA, the levels of relative proteins and autophagy. The MN progression in MN mice model was also studied. Albumin increased the miR-664a-5p content and apoptosis of HK-2 cells, which was blocked by miR-664a-5p antagomir. miR-664a-5p bound to the 3' UTR of HIPK2 mRNA, resulting in the up-regulation of Calpain1, GSα shear and the inhibition of autophagy level. Autophagy inhibitor CQ blocked the protective effect of miR-664a-5p antagomir, HIPK2 overexpression, Calpain inhibitor SJA6017 on albumin-mediated injury. MiR-664a-5p from albumin-treated HK-2 cells could be horizontally transported to podocytes through exosomes. Exosomes from albumin-treated HK-2 cells promoted progression of MN mice, AAV-Anti-miR-664-5p (mouse homology miRNA) could improve them. Albumin increases the miR-664a-5p level and causes changes of HIPK2/Calpain1/GSα pathway, which leads to autophagy inhibition and apoptosis up-regulation of renal tubular epithelial cells. miR-664a-5p can horizontally enter podocytes through exosomes resulting in podocytes injury. Targeted inhibition of miR-664a-5p can reduce the apoptosis of renal tubule cells and podocytes, and may improve the MN progression.

Mechanism of Liuwei Dihuang Pills in treating osteoporosis based on network pharmacology

Osteoporosis is a prevalent age-related disease that poses a significant public health concern as the population continues to age. While current treatments have shown some therapeutic benefits, their long-term clinical efficacy is limited by a lack of stable curative effects and significant adverse effects. Traditional Chinese Medicine has gained attention due to its positive curative effects and fewer side effects. Liuwei Dihuang Pill has been found to enhance bone mineral density in patients with osteoporosis and rats, but the underlying mechanism is not yet clear. To shed more light on this problem, this study aims to explore the pharmacological mechanism of Liuwei Dihuang Pill in treating osteoporosis using network pharmacology and molecular docking. The findings indicate that Liuwei Dihuang Pills treat osteoporosis through various targets and channels. Specifically, it mainly involves TNF, IL17, and HIF-1 signaling pathways and helps regulate biological processes such as angiogenesis, apoptosis, hypoxia, and gene expression. Furthermore, molecular docking demonstrates excellent binding properties between the drug components and key targets. Therefore, this study offers a theoretical foundation for understanding the pharmacological mechanism and clinical application of Liuwei Dihuang Pills in treating osteoporosis more comprehensively.