Metanephric mesenchyme-derived Foxd1+ mesangial precursor cells alleviate mesangial proliferative glomerulonephritis

SOCS1 Peptidomimetic Alleviates Glomerular Inflammation in MsPGN by Inhibiting Macrophage M1 Polarization

Mesangial proliferative glomerulonephritis (MsPGN), the most common pathological change in primary glomerulonephritis, is characterized by increased macrophage infiltration into glomeruli, which results in proinflammatory cytokine release. Macrophage infiltration and differentiation are induced by the Janus kinase 2 and signal transducer and activator of the transcription 1 (JAK2/STAT1) pathway. As a suppressor of cytokine signaling 1 (SOCS1) downregulates the immune response by inhibiting the JAK2/STAT1 pathway, we investigated whether a peptide mimicking the SOCS1 kinase inhibitor region, namely, SOCS1 peptidomimetic, protects against nephropathy. Glomerular JAK2/STAT1 pathway activation was synchronized with kidney injury in an MsPGN rat model. Rats treated with the SOCS1 peptidomimetic exhibited reduced pathological glomerular changes and lessened macrophage recruitment. Moreover, in vivo, the phosphorylation of the JAK2/STAT1 pathway was downregulated in infiltrated macrophages of glomeruli. In vitro, the SOCS1 peptidomimetic inhibited macrophage M1 polarization by suppressing JAK2/STAT1 activation. In conclusion, our study demonstrated that the SOCS1 peptidomimetic plays a protective role against pathologic glomerular changes in MsPGN by reducing macrophage infiltration and inhibiting macrophage polarizing to the M1 phenotype. SOCS1 peptidomimetic, therefore, presents a feasible therapeutic strategy to alleviate renal inflammation in MsPGN.

The therapeutic effect of Shenhua tablet against mesangial cell proliferation and renal inflammation in mesangial proliferative glomerulonephritis

Shenhua tablet (SH), a formulation of traditional Chinese medicine, exerts renoprotective effect on chronic kidney diseases, and it has been found to restrain inflammation, but the mechanism is still unclear. Here, we explored the potential renoprotection of SH in mesangial proliferative glomerulonephritis (MsPGN) rat model induced by anti-Thy1 antibody. Administration of SH reduced urinary albumin/creatinine ratio (UACR) and significantly attenuated mesangial cell proliferation and renal inflammation. Notably, SH protected rats against renal inflammation, which was associated with decreasing macrophage infiltration and promoting macrophage anti-inflammatory activity. Network analysis combined with arrays identified the Janus kinase signal transducer and activator of transcription (JAK-STAT) signaling pathway as the main pathways of SH could target inflammation. Furthermore, it was confirmed that mesangial cell proliferation, which response to inflammation, were alleviated by ASS1 expression enhanced after SH administration both in vivo and in vitro. Collectively, SH has the beneficial on relieving the progression of MsPGN to alleviate inflammation and mesangial proliferation by inhibiting STAT3 phosphorylation and maintains the expression level of ASS1, might be an effective strategy for treating MsPGN.

Differential expression profile of urinary exosomal microRNAs in patients with mesangial proliferative glomerulonephritis

OBJECTIVE

To investigate the differential expression profile of urinary exosomal microRNA (miRNA) in patients with mesangial proliferative glomerulonephritis (MsPGN) and healthy controls and their potential role in the pathogenesis of MsPGN.

METHODS

Urine specimens were collected from five MsPGN patients and five healthy controls, and differentially expressed miRNAs were screened using high-throughput sequencing technology. The sequenced urinary exosomal miRNAs were further investigated by quantitative real-time polymerase chain reaction (qRT-PCR) in a validation cohort (16 MsPGN patients and 16 healthy controls). Correlation and receiver operating characteristic (ROC) curve analyses were used to determine the association between clinical features and miRNA expression in MsPGN. Finally, fluorescence in situ hybridization was performed to detect miRNA expression in the renal tissues of MsPGN patients.

RESULTS

Five differentially expressed miRNAs (miR-125b-2-3p, miR-205-5p, let-7b-3p, miR-1262, and miR-548o-3p) were identified by qRT-PCR. The expression of these miRNAs correlated with ACR, 24hUpro, mAlb, UA, and combined yielded a ROC curve area of 0.916 in discriminating MsPGN patients from the controls. In addition, the expression of miR-205-5p, let-7b-3p, miR-1262, and miR-548o-3p was elevated in the MsPGN patient group, and miR-125b-2-3p was decreased in the MsPGN patient group.

CONCLUSIONS

Differential expression of urinary exosomal miRNAs may pose a risk of MsPGN and help distinguish MsPGN patients from controls. Certain miRNA expressions may be associated with disease progression, contributing to the epigenetic understanding of the pathophysiology of MsPGN.

Aqueous Extract and Polysaccharide of Aconiti Lateralis Radix Induce Apoptosis and G0/G1 Phase Cell Cycle Arrest by PI3K/AKT/mTOR Signaling Pathway in Mesangial Cells

Mesangial proliferative glomerulonephritis (MesPGN) is a common renal disease that lacks effective drug intervention. Aconiti Lateralis Radix (Fuzi), a natural Chinese medical herb, is found with significant therapeutic effects on various diseases in the clinic. However, its effects on MesPGN have not been reported. This study is aimed to discuss the therapeutic effects of the aqueous extract of Aconiti Lateralis Radix (ALR) and the polysaccharides of Aconiti Lateralis Radix (PALR) on MesPGN as well as the underlying mechanism. In this study, we, firstly, studied the anti-MesPGN mechanism of ALR and PALR. ALR and PALR inhibit the proliferation of the mesangial cells through the PI3K/AKT/mTOR pathway, induce the G0/G1 phase of block and apoptosis, inhibit the activity of Cyclin E and CDK2, increase the expression of Bax, cleaved caspase-8/caspase-8, and cleaved caspase-3/caspase-3 proteins, and effectively inhibit the growth of the mesangial cells. Overall, our data suggest that ALR and PALR may be potential candidates for MesPGN and that PALR is more effective than ALR.

Ameliorating role of microRNA-378 carried by umbilical cord mesenchymal stem cells-released extracellular vesicles in mesangial proliferative glomerulonephritis

BACKGROUND

Mesenchymal stem cells (MSCs) and their released extracellular vesicles (Evs) have shown protective effects against kidney diseases. This study aims to study the functions of umbilical cord MSCs-released Evs (ucMSC-Evs) and their implicated molecules in mesangial proliferative glomerulonephritis (MsPGN).

METHODS

A rat model of MsPGN was induced by anti-Thy-1.1, and rat mesangial cells (rMCs) HBZY-1 were treated with PDGF-BB/DD to mimic MsPGN condition in vitro. Rats and cells were treated with different doses of ucMSC-Evs, and then the pathological changes in renal tissues and proliferation of rMCs were determined. Differentially expressed microRNAs (miRNAs) after Evs treatment were screened by microarray analysis. The interactions among miR-378, PSMD14, and TGFBR1 were analyzed. Gain- and loss-of function studies of miR-378 and PSMD14 were performed to explore their effects on tissue hyperplasia and rMC proliferation and their interactions with the TGF-β1/Smad2/3 signaling pathway.

RESULTS

The ucMSC-Evs treatment ameliorated mesangial hyperplasia and fibrosis in rat renal tissues and suppressed the aberrant proliferation of rMCs in a dose-dependent manner. miR-378 was the most upregulated miRNA in tissues and cells after ucMSC-Evs treatment. miR-378 directly targeted PSMD14, and PSMD14 maintained the stability of TGFBR1 through deubiquitination modification, which led to TGF-β1/Smad2/3 activation. Either miR-378 knockdown or PSMD14 overexpression diminished the protective functions of ucMSC-Evs by activating the TGF-β1/Smad2/3 signaling pathway.

CONCLUSION

UcMSC-Evs ameliorate pathological process in MsPGN through the delivery of miR-378, which suppresses PSMD14-mediated TGFBR1 stability and inactivates the TGF-β1/Smad2/3 signaling pathway to reduce tissue hyperplasia and rMC proliferation. Video abstract.

Modulation of IL-6 Expression by KLF4-Mediated Transactivation and PCAF-Mediated Acetylation in Sublytic C5b-9-Induced Rat Glomerular Mesangial Cells

Interleukin-6 (IL-6) overproduction has been considered to contribute to inflammatory damage of glomerular mesangial cells (GMCs) in human mesangial proliferative glomerulonephritis (MsPGN) and its rat model called Thy-1 nephritis (Thy-1N). However, the regulatory mechanisms of IL-6 expression in GMCs upon sublytic C5b-9 timulation remain poorly understood. We found that Krüppel-like factor 4 (KLF4) bound to the IL-6 promoter (−618 to −126 nt) and activated IL-6 gene transcription. Furthermore, lysine residue 224 of KLF4 was acetylated by p300/CBP-associated factor (PCAF), which was important for KLF4-mediated transactivation. Moreover, lysine residue 5 on histone H2B and lysine residue 9 on histone H3 at the IL-6 promoter were also acetylated by PCAF, which resulted in an increase in IL-6 transcription. Besides, NF-κB activation promoted IL-6 expression by elevating the expression of PCAF. Overall, these findings suggest that sublytic C5b-9-induced the expression of IL-6 involves KLF4-mediated transactivation, PCAF-mediated acetylation of KLF4 and histones, and NF-κB activation in GMCs.

Exploring the Underlying Mechanism of Shenyankangfu Tablet in the Treatment of Glomerulonephritis Through Network Pharmacology, Machine Learning, Molecular Docking, and Experimental Validation

Purpose

This study aimed to explore the underlying mechanisms of Shenyankangfu tablet (SYKFT) in the treatment of glomerulonephritis (GN) based on network pharmacology, machine learning, molecular docking, and experimental validation.

Methods

The active ingredients and potential targets of SYKFT were obtained through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, the targets of GN were obtained through GeneCards, etc. Perl and Cytoscape were used to construct an herb-active ingredient–target network. Then, the clusterProfiler package of R was used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. We also used the STRING platform and Cytoscape to construct a protein–protein interaction (PPI) network, as well as the SwissTargetPrediction server to predict the target protein of the core active ingredient based on machine-learning model. Molecular-docking analysis was further performed using AutoDock Vina and Pymol. Finally, we verified the effect of SYKFT on GN in vivo.

Results

A total of 154 active ingredients and 255 targets in SYKFT were screened, and 135 targets were identified to be related to GN. GO enrichment analysis indicated that biological processes were primarily associated with oxidative stress and cell proliferation. KEGG pathway analysis showed that these targets were involved mostly in infection-related and GN-related pathways. PPI network analysis identified 13 core targets of SYKFT. Results of machine-learning model suggested that STAT3 and AKT1 may be the key target. Results of molecular docking suggested that the main active components of SYKFT can be combined with various target proteins. In vivo experiments confirmed that SYKFT may alleviate renal pathological injury by regulating core genes, thereby reducing urinary protein.

Conclusion

This study demonstrated for the first time the multicomponent, multitarget, and multipathway characteristics of SYKFT for GN treatment.

Activated mesangial cells induce glomerular endothelial cells proliferation in rat anti-Thy-1 nephritis through VEGFA/VEGFR2 and Angpt2/Tie2 pathway

OBJECTIVES

We aimed to investigate the underlying mechanism of endothelial cells (ECs) proliferation in anti-Thy-1 nephritis.

MATERIALS AND METHODS

We established anti-Thy-1 nephritis and co-culture system to explore the underlying mechanism of ECs proliferation in vivo and in vitro. EdU assay kit was used for measuring cell proliferation. Immunohistochemical staining and immunofluorescence staining were used to detect protein expression. ELISA was used to measure the concentration of protein in serum and medium. RT-qPCR and Western blot were used to qualify the mRNA and protein expression. siRNA was used to knock down specific protein expression.

RESULTS

In anti-Thy-1 nephritis, ECs proliferation was associated with mesangial cells (MCs)-derived vascular endothelial growth factor A (VEGFA) and ECs-derived angiopoietin2 (Angpt2). In vitro co-culture system activated MCs-expressed VEGFA to promote vascular endothelial growth factor receptor2 (VEGFR2) activation, Angpt2 expression and ECs proliferation, but inhibit TEK tyrosine kinase (Tie2) phosphorylation. MCs-derived VEGFA stimulated Angpt2 expression in ECs, which inhibited Tie2 phosphorylation and promoted ECs proliferation. And decline of Tie2 phosphorylation induced ECs proliferation. In anti-Thy-1 nephritis, promoting Tie2 phosphorylation could alleviate ECs proliferation.

CONCLUSIONS

Our study showed that activated MCs promoted ECs proliferation through VEGFA/VEGFR2 and Angpt2/Tie2 pathway in experimental mesangial proliferative glomerulonephritis (MPGN) and in vitro co-culture system. And enhancing Tie2 phosphorylation could alleviate ECs proliferation, which will provide a new idea for MPGN treatment.

KLF6 Acetylation Promotes Sublytic C5b-9-Induced Production of MCP-1 and RANTES in Experimental Mesangial Proliferative Glomerulonephritis

Rat Thy-1 nephritis (Thy-1N) is an experimental mesangial proliferative glomerulonephritis (MsPGN) for studying human MsPGN. Although sublytic C5b-9 complex formation on glomerular mesangial cells (GMCs) and renal MCP-1 and RANTES production in rats with Thy-1N have been proved, the role and mechanism of MCP-1 or RANTES synthesis in GMCs induced by sublytic C5b-9 are poorly elucidated. In this study, we first found the expression of transcription factor (KLF6), co-activator (KAT7) and chemokines (MCP-1 and RANTES) was all up-regulated both in renal tissue of Thy-1N rats (in vivo) and in sublytic C5b-9-induced GMCs (in vitro). Further in vitro experiments revealed that KLF6 bound to MCP-1 promoter (-297 to -123 nt) and RANTES promoter (-343 to -191 nt), leading to MCP-1 and RANTES gene transcription. Meanwhile, KAT7 also bound to the same region of MCP-1 and RANTES promoter in a KLF6-dependent manner, and KLF6 was acetylated by KAT7 at lysine residue 100, which finally promoted MCP-1 and RANTES expression. Moreover, our in vivo experiments discovered that knockdown of renal KAT7 or KLF6 gene obviously reduced MCP-1 and RANTES production, GMCs proliferation, ECM accumulation, and proteinuria secretion in Thy-1N rats. Collectively, our study indicates that sublytic C5b-9-induced MCP-1 and RANTES synthesis is associated with KAT7-mediated KLF6 acetylation and elevated KLF6 transcriptional activity, which might provide a new insight into the pathogenesis of rat Thy-1N and human MsPGN.

Justicidin B Inhibits PDGF-BB-Induced Proliferation and ECM Accumulation in Mesangial Cells via Nrf2/HO-1 and Akt/mTOR Signaling Pathway

Mesangial proliferative glomerulonephritis (MsPGN) is characterized by mesangial cell proliferation, inflammation, and extracellular matrix deposition in the mesangial area, which develops into glomerulosclerosis and contributes to end-stage renal disease. Justicidin B is a bioactive compound isolated from Justicia procumbens L., a traditional herbal remedy that reduces proteinuria in nephritis. However, the mechanism of Justicidin B’s therapeutic effect on MsPGN remains unclear. This study was aimed to explore the positive effect of Justicidin B on MsPGN. The results showed that Justicidin B attenuated the proliferation induced by platelet-derived growth factor-BB (PDGF-BB) in MCs and blocked cell cycle progression. Likewise, inflammatory factors, including monocyte chemotactic protein 1 (MCP-1) and tumor necrosis factor alpha (TNF-α), in MCs were decreased after treatment with Justicidin B. In addition, Justicidin B exhibited antioxidant activity in PDGF-BB-induced MCs, shown by the decreased production of malondialdehyde and T-AOC, and increased the expression of superoxide dismutase. Besides, Justicidin B suppressed extracellular matrix (ECM) deposition by reducing the protein levels of collagen IV and fibronectin. Furthermore, we found that Justicidin B significantly inhibited activation of the Akt/mammalian target of rapamycin (mTOR) signaling pathway in MCs induced by PDGF-BB, but enhanced the levels of proteins in the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. Taken together, Justicidin B prevented PDGF-BB-induced proliferation, inflammation, oxidative stress, and ECM accumulation via regulating the activation of the Nrf2/HO-1 pathway and the Akt/mTOR signaling pathway.