Increased soluble ST2 and IL‑4 serum levels are associated with disease severity in patients with membranous nephropathy

MicroRNA-382 Promotes M2-Like Macrophage via the SIRP-α/STAT3 Signaling Pathway in Aristolochic Acid-Induced Renal Fibrosis

Aristolochic acid nephropathy (AAN) is a type of drug-induced nephropathy and is correlated with a potentially progression of kidney fibrosis. However, whether miR-382 is implicated in macrophage activation in AA-induced kidney fibrosis remains elusive. Here, cell-sorting experiments defined a significant miR-382 enrichment in renal macrophage after AAN 14 days. Then, we found that treatment of AA induced a significant switch in the phenotype of macrophage both in vivo and in vitro. Furthermore, miR-382 knockout (KO) mice and miR-382-/- bone marrow-derived macrophage (BMDM) were subjected to AA induction. We found that both systemic KO and macrophage-specific miR-382 depletion notably suppressed M2-like macrophage activation as well as kidney interstitial fibrosis. Additionally, adoptive transfer of miR-382 overexpression BMDMs into mice promoted AA-induced kidney injury. Moreover, in cultured macrophage, upregulation of miR-382 promoted M2-related gene expression, accompanied by downregulation of signal regulatory protein α (SIRP-α) and activation of signal transducer and activator of transcription 3 (STAT3). The interaction between miR-382 and SIRP-α was evaluated via dual-luciferase assay. Knockdown of SIRP-α upregulated phosphorylated STAT3 at S727 and Y705. Pharmacological inhibition of STAT3 was performed both in vivo and in vitro. Inhibition of STAT3 attenuated AA-induced kidney fibrosis, in parallel to lesser macrophage M2 polarization. Coculture experiments further confirmed that overexpressed miR-382 in macrophage promoted injuries of tubular cells. Luminex bio-chip detection suggested that IL-4 and CCL-5 were critical in the cross talk between macrophages and tubular cells. Taken together, our data suggest that miR-382 is a critical mediator in M2-like macrophage polarization and can be a promising therapeutic target for kidney fibrosis.

The Potential Role of Regulatory B Cells in Idiopathic Membranous Nephropathy

Regulatory B cells (Breg) are widely regarded as immunomodulatory cells which play an immunosuppressive role. Breg inhibits pathological autoimmune response by secreting interleukin-10 (IL-10), transforming growth factor-β (TGF-β), and adenosine and through other ways to prevent T cells and other immune cells from expanding. Recent studies have shown that different inflammatory environments induce different types of Breg cells, and these different Breg cells have different functions. For example, Br1 cells can secrete IgG4 to block autoantigens. Idiopathic membranous nephropathy (IMN) is an autoimmune disease in which the humoral immune response is dominant and the cellular immune response is impaired. However, only a handful of studies have been done on the role of Bregs in this regard. In this review, we provide a brief overview of the types and functions of Breg found in human body, as well as the abnormal pathological and immunological phenomena in IMN, and propose the hypothesis that Breg is activated in IMN patients and the proportion of Br1 can be increased. Our review aims at highlighting the correlation between Breg and IMN and proposes potential mechanisms, which can provide a new direction for the discovery of the pathogenesis of IMN, thus providing a new strategy for the prevention and early treatment of IMN.

Both Peripheral Blood and Urinary miR-195-5p, miR-192-3p, miR-328-5p and Their Target Genes PPM1A, RAB1A and BRSK1 May Be Potential Biomarkers for Membranous Nephropathy

Background

To identify noninvasive diagnostic biomarkers for membranous nephropathy (MN).

Material/Methods

The mRNA microarray datasets GSE73953 using peripheral blood mononuclear cells (PBMCs) of 8 membranous nephropathy patients and 2 control patients; and microRNAs (miRNA) microarray dataset GSE64306 using urine sediments of 4 membranous nephropathy patients and 6 control patients were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were respectively identified from PBMCs and urine sediments of membranous nephropathy patients, followed with functional enrichment analysis, protein-protein interaction (PPI) analysis, and miRNA-target gene analysis. Finally, the DEGs and the target genes of DEMs were overlapped to obtain crucial miRNA-mRNA interaction pairs for membranous nephropathy.

Results

A total of 1246 DEGs were identified from PBMCs samples, among them upregulated CCL5 was found to be involved in the chemokine signaling pathway, and BAX was found to be apoptosis related; while downregulated PPM1A and CDK1 were associated with the MAPK signaling pathway and the p53 signaling pathway, respectively. The hub role of CDK1 (degree=18) and CCL5 (degree=12) were confirmed after protein-protein interaction network analysis in which CKD1 could interact with RAB1A. A total of 28 DEMs were identified in urine sediments. The 276 target genes of DEMs were involved in cell cycle arrest (PPM1A) and intracellular signal transduction (BRSK1). Thirteen genes were shared between the DEGs in PMBCs and the target genes of DEMs in urine sediments, but only hsa-miR-192-3p-RAB1A, hsa-miR-195-5p-PPM1A, and hsa-miR-328-5p-BRSK1 were negatively related in their expression level.

Conclusions

Both peripheral blood and urinary miR-195-5p, miR-192-3p, miR-328-5p, and their target genes PPM1A, RAB1A, and BRSK1 may be potential biomarkers for membranous nephropathy by participating in inflammation and apoptosis.