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.

Baicalin Reduces Renal Inflammation in Mesangial Proliferative Glomerulonephritis through Activation of Nrf2/ARE and PI3K/AKT Pathways

OBJECTIVE

Mesangial proliferative glomerulonephritis (MPGN) is a prevalent form of primary glomerulonephritis, distinguished by the proliferation of mesangial cells and the accompanying inflammatory response. Baicalin, the active ingredient in the Scutellaria baicalensis Georgi plant, has been observed to have a protective effect on the kidneys. However, its specific impact on MPGN has yet to be studied widely. Hence, this study aimed to investigate the effect on MPGN and the underlying mechanisms of Baicalin.

METHODS

Thirty-six Sprague-Dawley (SD) rats, aged 6 to 8 weeks, were randomly allocated into different subgroups: control, model, benazepril, and three baicalin subgroups (low, medium, and high dose), each consisting of six rats. The concentrations of 24-hour urinary protein, blood urea nitrogen (BUN), serum creatinine (SCr), triglycerides (TG), total cholesterol (TC), interleukins (IL-1α, IL-2, IL-10), and interferon-γ (IFN-γ) were measured with biochemistry. The pathological alterations in the renal tissue were examined using Hematoxylin and Eosin (HE) along with Periodic Acid-Schiff (PAS) staining. Concurrently, the extent of apoptosis was evaluated using TdT-mediated dUTP nick end labeling (TUNEL) staining. In vitro, mesangial cells were exposed to 30 μg/mL lipopolysaccharide for 24 h, with or without varying concentrations of baicalin (10, 20, 40 μM). MTT assay was applied to estimate cell activity, flow cytometry to evaluate the cell cycle, and 5-ethynyl-2-deoxyuridine (EdU) detection to measure cell proliferation. IL-1α, IL-2, IL-10, and IFN-γ concentrations in the cell supernatant were assayed with biochemistry. Furthermore, the expression of apoptosis-related proteins, concluding BCL2-Associated X (Bax), Bcl-2, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), and caspase-1, NF-E2-related factor 2/antioxidant response element (Nrf2/ARE) pathway-related proteins (Nrf2 and HO-1), and phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) pathway-related proteins (p-PI3K, PI3K, p-AKT, and AKT) in both the renal tissue and cell supernatant were measured.

RESULTS

Baicalin treatment significantly reduced the 24-hour urinary protein, serum levels of BUN, SCr, TG, TC, IL-1α, IL-2, IL-10, and IFN-γ in vivo experiments. Baicalin treatment also improved the pathological condition of renal tissue and decreased the occurrence of apoptosis. In vitro, findings confirmed that baicalin inhabits the proliferation of mesangial cells triggered by Lipopolysaccharide (LPS), induces a G1 phase cell cycle arrest, and reduces the concentrations of IL-1α, IL-2, IL-10, and IFN-γ. Baicalin also decreased the ratios of p-PI3K/PI3K and p-AKT/AKT while enhancing the levels of Nrf2 and HO-1 in both renal tissue and cell supernatant.

CONCLUSIONS

Baicalin can mitigate MPGN by impeding the proliferation and inflammation of mesangial cells by activating Nrf2/ARE and PI3K/AKT pathways.

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.

Overlap of Thrombotic Microangiopathy and Mesangial Proliferative Glomerulonephritis Caused by Combination Therapy with Atezolizumab and Bevacizumab

Vascular endothelial growth factor inhibitors and checkpoint inhibitors are effective treatments for solid tumors. These new classes of anti-cancer agents frequently cause kidney-related side effects. Although their anti-cancer effects may be enhanced when used in combination, the severity of their kidney-related side effects is unknown. We herein report the first case of thrombotic microangiopathy and mesangial proliferative glomerulonephritis caused by combined treatment with atezolizumab and bevacizumab in a 74-year-old man with hepatocellular carcinoma. The combination therapy was discontinued and replaced with intravenous methylprednisolone followed by oral prednisolone. Subsequently, the urinary protein excretion levels declined.

Focal segmental glomerulosclerosis in patients after Fontan operation: is this a Fontan-associated renal disease?

Despite acceptable survival for Fontan operation, there are concerns about late complications affecting the major organs. We herein present two cases of adults after Fontan operation who developed focal segmental glomerulosclerosis. These cases suggest that focal segmental glomerulosclerosis is owing to haemodynamic incompetence associated with Fontan operation, including congestion, hypoxia, and hyperviscosity, which may be called Fontan-associated renal disease.

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.

Expression and clinical significance of thrombospondin-1 and plasminogen activator inhibitor-1 in patients with mesangial proliferative glomerulonephritis

BACKGROUND

As a common pathological type of glomerular disease in China, mesangial proliferative glomerulonephritis is related to plasminogen activator inhibitor-1 (PAI-1) and thrombospondin-1 (TSP-1). Here, this study aims to investigate the expression and clinical significance of TSP-1 and PAI-1 in patients with mesangial proliferative glomerulonephritis.

METHODS

Renal tissue specimens from 46 patients with mesangial proliferative glomerulonephritis admitted to this hospital were selected as the subjects, and 8 specimens of renal tissue from autopsy were used as controls. The expression levels of TSP-1 and PAI-1 were detected by immunohistochemistry and analyzed.

RESULTS

The 24-hour urine protein, triglyceride, and total cholesterol levels of patients with severe mesangial hyperplasia were significantly higher than those of patients with mild and moderate mesangial hyperplasia, and serum albumin was lower than that of patients with mild and moderate mesangial hyperplasia (P<0.05). The 24-hour urine protein level of patients with moderate mesangial hyperplasia was higher than that of patients with mild mesangial hyperplasia while the albumin level was lower (P<0.05), but there was no significant difference in triglyceride and total cholesterol (P>0.05). There was no significant difference in creatinine clearance (Ccr) between the three groups (P>0.05).The 24-hour urine protein and urine alpha-1-microglobulin (A1M) levels in patients with renal interstitial disease were higher than those in patients without renal interstitial disease, while their Ccr level was lower (P<0.05). TSP-1 and PAI-1 were not positively expressed in the glomeruli and renal tubules of specimens of the control group. However, in mesangial hyperplasia patients, the expression of TSP-1 and PAI-1 in mesangial hyperplasia with varying degrees and in different renal tubular damage were as follows: mild degree < moderate degree < severe degree (P<0.05).

CONCLUSIONS

The pathological changes of mesangial proliferative glomerulonephritis are related to 24- hour urine protein, triglyceride, total cholesterol level, urine A1M, and Ccr level. The expression of TSP1 and PAI-1 in the mesenchyme of glomerular and renal tubules significantly increased with the severity of the disease, suggesting that TSP-1 and PAI-1 play an important role in the occurrence and development of mesangial proliferative glomerulonephritis.

Paeoniflorin Inhibits Mesangial Cell Proliferation and Inflammatory Response in Rats With Mesangial Proliferative Glomerulonephritis Through PI3K/AKT/GSK-3β Pathway

Mesangial proliferative glomerulonephritis (MPGN) is the most common type of chronic kidney disease in China, characterized by mesangial cell proliferation and inflammatory response. Paeoniflorin, an effective composition extracted from Radix Paeoniae Alba, has been used for various kinds of kidney diseases. However, there are no studies reporting the effects of paeoniflorin on MPGN. The present study aims to investigate whether paeoniflorin plays a role in MPGN and confirm the underlying molecular mechanisms. Our results manifested that paeoniflorin strongly restrained 24 h urinary protein and promoted renal function and dyslipidemia in a MPGN rat model. Moreover, paeoniflorin attenuated mesangial cell proliferation and inflammation both in MPGN rats and human mesangial cells (HMCs) treated with lipopolysaccharide (LPS). In detail, paeoniflorin decreased the number of mesangial cells and expressions of proliferation marker Ki67 in MPGN rats. Paeoniflorin also inhibited HMC proliferation and blocked cell cycle progression. In addition, the contents of inflammatory factors and the expressions of macrophage marker iNOS were decreased after paeoniflorin treatment. Furthermore, we found that the protective effect of paeoniflorin was accompanied by a strong inhibition of the phosphatidylinositol 3-kinase (PI3K)/AKT/glycogen synthase kinase (GSK)-3β pathway. Paeoniflorin enhanced the inhibitory effect of PI3K inhibitor LY294002 and suppressed the activated effect of PI3K agonist insulin-like growth factor 1 (IGF-1) on PI3K/AKT/GSK-3β pathway. In conclusion, these results demonstrated that paeoniflorin ameliorates MPGN by inhibiting mesangial cell proliferation and inflammatory response through the PI3K/AKT/GSK-3β pathway.

Suppressor of Cytokine Signaling-1/STAT1 Regulates Renal Inflammation in Mesangial Proliferative Glomerulonephritis Models

Mesangial proliferative glomerulonephritis (MsGN) is a significant global threat to public health. Inflammation plays a crucial role in MsGN; however, the underlying mechanism remains unknown. Herein, we demonstrate that suppression of the cytokine signaling-1 (SOCS1)/signal transducer and activator of transcription 1 (STAT1) signaling pathway is associated with renal inflammation and renal injury in MsGN. Using MsGN rat (Thy1.1 GN) and mouse (Habu GN) models, renal SOCS1/STAT1 was determined to be associated with CD4+ T cell infiltration and related cytokines. In vitro, SOCS1 overexpression repressed IFN-γ-induced MHC class II and cytokine levels and STAT1 phosphorylation in mesangial cells. SOCS1 and STAT1 inhibitors significantly inhibited IFN-γ-induced CIITA promoter activity and MHC class II expression. In conclusion, our study emphasizes the pivotal role of the SOCS1/STAT1 axis in the regulation of inflammation in MsGN.

IgA nephropathy in a girl with mitochondrial disease

Mitochondrial renal disease is one of the important causes of end-stage renal disease in children and its incidence may be underestimated. We here describe the case of a 13-year-old girl who was diagnosed with mitochondrial disease (MD) accompanied by IgA nephropathy (IgAN). She presented with persistent proteinuria, short stature, and hearing defect, and her younger sister had the same symptoms. Renal biopsy indicated mild focal segmental mesangial proliferation with dominant mesangial IgA deposition on immunofluorescence. Electron microscopy showed marked proliferation of abnormal mitochondria in the proximal tubular cells. Enzyme activity of the mitochondrial respiratory chain complex I and IV in cultured skin fibroblasts was significantly decreased. This case indicated the possible co-occurrence of IgAN and MD. Underlying MD should be considered in patients with urine abnormalities, especially in those with multiple organ involvement.

Multicentric Castleman's disease with renal amyloidosis and mesangial proliferative glomerulonephritis: a case report

Renal involvement is a significant complication of multicentric Castleman's disease (MCD) and various glomerular involvements have been reported. A 56-year-old Chinese woman presented with proteinuria and skin rash, with lymphadenopathy and hypergammaglobulinemia. Lymph nodes and skin biopsy proven the case was multicentric CD with plasma cell pathological pattern. The renal biopsy was performed and six glomeruli were observed and two of these showed global sclerosis. Moderate increasing of mesangial matrix with mesangial cell proliferation were seen in every glomerulus. In addition, one-segmental sclerosis accompanied by adhesion of the Bowman's capsule was revealed. Two of the glomeruli had crescents formation. Under immunofluorescence microscopy, immunofluorescence for anti-IgA, IgM, C3, C1q and FRA showed coarse and fine granular depositions along capillary walls and sparsely in the mesangium. Staining for anti-IgG was negative. Under electron microscopy revealed indiscriminate amyloidal deposits in glomerular basement membrane. The foot process of glomerular podocytes was fusion. Moderate increasing of mesangial matrix and mesangial cell proliferation were found. Subsequently, she was successfully treated with prednisone combined with cyclophosphamide therapy not only for proteinuria but also for renal function.

Association of human leukocyte antigen gene polymorphism and mesangial proliferative glomerulonephritis in a large population-based study

The aim of the present study was to investigate the association of human leukocyte antigen (HLA) gene polymorphism and clinical phenotypes of patients with mesangial proliferative glomerulonephritis (MsPGN). The genotyping of HLA-A, HLA-B and HLA-DRB1 alleles was detected in 1,536 consecutive MsPGN patients during the previous five years and 2,027 age- and gender-matched healthy individuals by using the polymerase chain reaction-sequence-specific primers method. The clinical and pathological data of the patients were collected and the genotype frequencies (GF) and odds ratio (OR) were analyzed. The allele frequencies of HLA-A*23, A*25, B*15, B*40, B*53 and DRB1*18 were significantly higher in MsPGN patients than in the controls (P<0.05). These alleles were considered as the suspected susceptibility genes (SSG) for MsPGN. Of note, results of the follow-up survey study demonstrated poorer prognosis of patients with SSG than those without SSG. On the other hand, the frequencies of A*32, A*33, B*50, B*58, B*60, B*71, DRB1*16 were lower in MsPGN patients than in the controls (P<0.05). However, the alleles A*20, A*22, A*35, A*36, A*38, B*21, B*73 and B*78 were not expressed in MsPGN patients. HLA gene polymorphism is associated with hereditary susceptibility to MsPGN. Therefore, there might be corresponding susceptibility and protective genes associated with MsPGN.