Characteristics of renal pathology and coagulation function in IgA nephropathy and IgA vasculitis associated nephritis.

BACKGROUND: The objective of this study is to investigate the clinical and pathological differences between patients with IgA nephropathy (IgAN) and IgA vasculitis associated nephritis (IgAVN). METHODS: A total of 253 patients with IgAN and 71 patients with IgAVN were retrospectively included in the study, and clinical and laboratory data were collected and analysed. RESULTS: Compared with IgAVN group, months from onset to kidney biopsy were significantly prolonged in IgAN patients because of the lack of obvious symptoms such as rash, abdominal symptoms, and joint pain (13.5 ± 26.6 vs. 10.2 ± 31.6 months, P = 0.007), and the levels of serum creatinine (92.3 ± 94.7 vs. 68.9 ± 69.2 µmol/L, P = 0.015) was higher and eGFR (99.1 ± 35.2 vs. 123.4 ± 41.8 mL/min/1.73m2, P < 0.001) was lower in IgAN group. The pathological results revealed that patients with IgAN have a greater degree of chronic kidney injury compared to patients with IgAVN. In addition, the levels of plasma D-Dimers (1415.92 ± 1774.69 vs. 496.78 ± 711.91 ng/mL, P < 0.001) and fibrinogen degradation products (FDP) (3.92 ± 4.73 vs. 1.63 ± 2.46 µg/mL, P = 0.001) were significantly higher in IgAVN patients than in IgAN patients. The deposition of fibrinogen in the renal tissues was more severe and the cumulative partial remission rate was higher in patients with IgAVN as compared to those with IgAN (P = 0.001). CONCLUSIONS: In comparison, IgAN patients had poorer renal function, whereas IgAVN patients had more severe coagulation abnormalities. These findings provide a basis for the differentiation of the two diseases at an early stage.

Rosiglitazone Inhibits Angiotensin II-Induced Proliferation of Glomerular Mesangial Cells via the Gαq/Plcß4/TRPC Signaling Pathway.

BACKGROUND/AIMS: Mesangial cell proliferation and extracellular matrix accumulation (ECM) deposition play an important role in the pathogenesis of glomerulosclerosis. TRPC and PPAR-γ can regulate cell proliferation. Angiotensin II (AngII) can induce mesangial cell proliferation and affect TRPC expression. However, the mechanism has not been fully elucidated. This study was designed to investigate the role of TRPC and the effect of rosiglitazone (RSG) in the proliferation of rat glomerular mesangial cells (HBZY-1) that were stimulated by AngII and the underlying mechanisms. METHODS: Immunofluorescence staining and qRT-PCR were performed to examine the expression levels of TRPCs in HBZY-1. Gene expression levels of TRPC, PPAR-γ, RGS4 (regulators of G protein signaling), the GPCR/Gαq/PLCß4/TRPC signaling pathway and major downstream molecules (PCNA, SKP2, P21 and P27) were detected by qRT-PCR and western blotting. Additionally, changes in intracellular Ca2+ levels were determined through Fluo-4 Ca2+ imaging, and the cell cycle was analyzed by flow cytometry. RESULTS: Our results found that TRPC1 and 6 were at higher expression levels in HBZY-1 cells. Following AngII stimulation, there were increased levels of TRPC1 and 6, Ca2+ entry, PCNA and SKP2, decreased expression levels of P21 and P27 and a reduced G0/G1 percentage. Silencing TRPC1 and 6 by siRNAs led to decrease in Ca2+ influx, G0/G1 cell cycle arrest and cell proliferation. Notably, PPAR-γ activation by RSG upregulated RGS4 expression, which can interact with the Gαq family to inhibit the Gαq-mediated signaling cascade. The results were similar to silencing TRPC1 and 6 by siRNAs. CONCLUSION: All these results indicate that RSG could inhibit HBZY-1 cell proliferation via the Gαq/PLCß4/TRPC signaling pathway.

Therapeutic Effects of FK506 on IgA Nephropathy Rat.

BACKGROUND/AIMS: FK506 is an immunosuppressive drug and a calcineurin inhibitor that has been widely used in kidney disease in recent years. FK506 shows a wide range of biological and pharmaceutical effects; however, the mechanism of its anti- proliferative effect has not been well elucidated. An IgA nephropathy (IgAN) model was used to generate a mesangial cell proliferation model. This study aims to examine the effect of FK506 on IgAN rats and the underlying mechanisms. METHODS: Hematuria, proteinuria and renal function were measured. To observe the pathological conditions, we performed HE (hematoxylin - eosin) and PAS (periodic acid - schiff) staining. Transcription and protein expression levels were detected by qRT - PCR (quantitative real-time polymerase chain reaction) and Wb (western blotting). The location and semi-quantitative expression levels of TRPCs, CaN (Calcineurin) and α-SMA were examined by IHC (Immunohistochemical staining). RESULTS: We found that FK506 could improve hematuria, proteinuria and renal function, especially in the HF (high-dose FK506) groups. Renal pathological changes were ameliorated in the treatment groups. FK506 could significantly decrease TRPCs, CaN, phosphorylation of ERK1/2 and α-SMA expression. CONCLUSION: Taken together, these results suggest that the therapeutic effect of FK506 on IgAN might be partially associated with the down-regulated expression of TRPC channels, CaN and phosphorylation of ERK1/2.

SEMA7A as a Novel Prognostic Biomarker and Its Correlation with Immune Infiltrates in Breast Cancer.

Background: The role of Semaphorin 7a (SEMA7A) in the initiation and progression of different types of cancerous lesions has been extensively studied. However, the prognostic significance of SEMA7A, specifically in breast cancer (BC), lacks clarity. Methods: We conducted an evaluation on the relationship between SEMA7A and the prognosis, immune invasion and tumor mutation burden in different types of cancer by analyzing data from The Cancer Genome Atlas database. The present study focused on investigating the expression level, mutation, immune correlation and coexpression of SEMA7A in BC, utilizing various databases such as the University of Alabama at Birmingham Cancer data analysis portal, cBioPortal and tumor immune estimation resource. Survival analysis was carried out using the Kaplan-Meier Plotter. Furthermore, we employed the R software package to generate receiver operating characteristic (ROC) curves and nomograms. Notably, P<0.05 was considered to indicate statistical significance. Results: Using pancancer analysis, it has been observed that the expression of SEMA7A is elevated in various types of cancer and is strongly correlated with the prognosis of different cancer types. SEMA7A also exhibits a significant association with the tumor mutation burden of diverse types of cancer. Moreover, SEMA7A displays a notable increase in BC cases, and was indicated to have a substantial association with the abundance of immune infiltration. In-depth survival analysis demonstrated that elevated levels of SEMA7A expression are notably linked to shorter overall survival and distant metastasis-free survival among patients with BC. The efficiency of SEMA7A as a reliable prognostic biomarker for BC has been substantiated by the validation of ROC curves and nomograms. Conclusion: SEMA7A has the potential to function as a prognostic indicator for BC, and its correlation with immune infiltration in BC is significant.

Association of ADP­ribosylation factor family genes with prognosis and immune infiltration of breast cancer.

Breast cancer (BC) is the most common type of cancer found in women. ADP-ribosylation factors (ARFs) are a group of small proteins that bind to GTP and are involved in controlling different cellular functions. The function and evolution of multiple ARFs in BC have remained to be fully elucidated, despite existing studies on this protein family in Homo sapiens and other species. In the present study, a systematic analysis of ARF expression levels in BC tissues compared to normal breast tissues was performed using data from The Cancer Genome Atlas database. The analysis revealed significantly higher expression of ARFs in BC tissues. In addition, the prognostic significance of ARF1 and ARF3-6 expression levels was assessed in patients with BC. Of note, elevated ARF1 expression was associated with reduced rates of distant metastasis-free survival (DMFS), overall survival (OS) and recurrence-free survival (RFS) in affected individuals. Similarly, patients with high expression levels of ARF3 had lower post-progression survival (PPS) rates. In addition, patients with higher ARF4 expression had worse PPS and patients with high ARF5 expression exhibited lower DMFS. Patients with high ARF6 expression had worse DMFS, OS, RFS and predictive power score values. Furthermore, the expression of ARF was found to be strongly linked to the infiltration of various immune cell types, namely dendritic cells, macrophages, neutrophils, CD8+ T cells and B cells. These significant associations offer a solid foundation for the potential utilization of new therapeutic targets and predictive markers for the treatment of BC.

Comprehensive pan­cancer analysis of MTDH for human tumor prognosis and as an immunological biomarker including breast and kidney cancer.

Metadherin (MTDH), initially discovered in primary astrocytes of the human fetus through rapid subtraction hybridization and labeled as astrocyte elevated gene-1, represents a widely recognized oncogene present in multiple types of cancers. However, the role of MTDH in different types of cancer remains unclear. To address this, a comprehensive analysis of MTDH across various types of cancers was conducted by utilizing multiple databases such as The Cancer Genome Atlas. The present analysis discovered that MTDH exhibits differential expression in different types of cancer and is associated with important factors including tumor mutational burden and microsatellite instability. These findings highlighted the significance of MTDH in the tumor microenvironment and its involvement in the development of immune cells in specific cancers. Furthermore, the results of the present study indicated that the expression of MTDH is strongly correlated with clinical prognosis, mutations and immune cell infiltration. MTDH could serve as a potential indicator of patient prognosis and potentially play a role in modulating the immune system. Given its potential as a novel immunological checkpoint, MTDH may be a viable target for tumor immunotherapy.

WIP1-mediated regulation of p38 MAPK signaling attenuates pyroptosis in sepsis-associated acute kidney injury.

Wild-Type p53-Induced Phosphatase 1 (WIP1/PPM1D) is a serine/threonine phosphatase that plays a significant role in various physiological processes. However, the involvement of WIP1 in kidney remains unclear. Lipopolysaccharide (LPS) was administered to induce acute injury in mice and human kidney 2 (HK2) cells in the study. The WIP1 inhibitor, CCT007093, was administered both in vitro and in vivo to assess its effect on kidney. The single-cell sequencing (scRNA-seq) data revealed that Ppm1d mRNA reached peak on day 2 following unilateral ischemia-reperfusion injury (uni-IRI) in mice, especially in the proximal renal tubules during repair phase. Compared to the control group, WIP1 protein exhibited a significant increase in renal tubules of patients with acute tubular injury (ATI) and mice with LPS-induced acute kidney injury (AKI), as well as in LPS-injured HK2 cells. In vitro experiments showed that CCT007093 increased the protein levels of NLRP3, cleaved-Caspase1, GSDMD-N and IL-1ß in HK2 cells and further reduced the viability of LPS-stimulated HK2 cells. In vivo experiments showed that inhibition of WIP1 activity with CCT007093 further increased cleaved-Caspase1, GSDMD-N protein levels in kidney tissue from mice with LPS-induced AKI. In addition, LPS induces phosphorylation of p38 MAPK, a key regulator of pyroptosis, which is further activated by CCT007093. In conclusion, inhibition of WIP1 activity acts as a positive regulator of renal tubular pyroptosis mainly through the mediation of phospho-p38 MAPK.

TIPE2, a novel biomarker for clinical chronic kidney allograft rejection.

Tumor necrosis factor-a--induced protein 8-like 2 (TIPE2) has an essential role in immune homeostasis, yet the relationship between TIPE2 expression and allograft rejection has not been addressed. Dependent on clinical diagnosis, 96 kidney transplant recipients were divided into three groups, long-term survival group, acute rejection group (AR) and chronic rejection group (CR). Thirty-two healthy volunteers were used as a control group. The expression of TIPE2 in peripheral blood mononuclear cells (PBMC) and kidney biopsy samples was performed using reverse transcript-polymerase chain reaction, immunohistochemistry and immunofluorescence. The expression of TIPE2 in PBMC of CR group was significantly higher than that of the healthy control (P < 0.001), but TIPE2 expression in AR group was lower than that of control individuals (P < 0.05). The renal expression of TIPE2 in allograft tissue of CR was significantly lower and its expression in AR slightly lower than in normal kidneys. The positive correlation between TIPE2 expression in PBMCs and the CR of allo-kidney grafts indicates that detection of TIPE2 in the blood samples may be used as one of the diagnosis molecular markers in clinical monitoring kidney chronic rejection.

Premature senescence and cellular phenotype transformation of mesangial cells induced by TGF-B1.

BACKGROUND: Transforming growth factor-ß1 (TGF-ß1) is a polypeptide member of the transforming growth factor ß superfamily of cytokines and performs many cellular functions. Its overexpression may lead to renal fibrosis. AIM: This study planed to investigate the effects of TGF-ß1 on the cell cycle and phenotype of mesangial cells. METHODS: Rat mesangial cells were cultured together with different concentrations (0, 1, 2, 5, and 10 ng/mL) of TGF-ß1 for specified times from 0 min to 72 h. 0 ng/mL TGF-ß1 and 0 min served as controls. Cell cycles were assessed by flow cytometry and α-smooth muscle actin expression (α-SMA) protein expression by western blot analysis. All data were presented as Mean ± SD. Statistical analysis was performed by using one-way analysis of variance and correlation analysis. Results were considered significant at p < 0.05. RESULTS: After 15 min of co-culture with different concentrations of TGF-ß1, the percentage of mesangial cells in G0/G1 phase was significantly elevated compared to the control (p < 0.05). 12 h co-culture induced cell hyperplasia, 24 h co-culture obvious up-regulation of α-SMA (p < 0.01) and one or two cells' myofibroblast phenotype transition, and 36 h co-culture several cells' phenotype transition. Correlation analysis prompted that the TGF-ß1-induced premature aging was time-dependent (p < 0.01). CONCLUSION: TGF-ß1 may induce mesangial cells' premature senescence and myofibroblast-like phenotype transformation time-dependently, which may contribute to the development of early stage of glomerulosclerosis.

A Study on the Role of Wip1 in Renal Fibrosis by Modulating Macrophage Phenotype.

BACKGROUND: Renal fibrosis is the result of chronic kidney diseases, the exploration of the pathogenesis of renal fibrosis and the development of effective treatment methods have become major challenges. AIMS: To investigate the effect of wild-type p53-induced phosphatase 1 (Wip1) on macrophage phenotype regulation and the role played in renal fibrosis. METHODS: RAW264.7 macrophages were stimulated by lipopolysaccharide (LPS) plus interferon-γ (IFN-γ) or interleukin 4 (IL-4) to differentiate into M1 or M2 macrophages. Lentivirus vectors were transduced into RAW264.7 macrophages to construct the cell lines that overexpressed or silenced Wip1, respectively. Furthermore, E-cadherin, Vimentin, and α-SMA levels of primary renal tubular epithelial cells (RTECs) were measured after co-culture with macrophages overexpressed or silenced by Wip1. RESULTS: Macrophages stimulated by LPS plus IFN-γ differentiated into M1 macrophages with high expression of iNOS and TNF-α, while those stimulated by IL-4 differentiated into M2 macrophages with high expression of Arg-1 and CD206. Increased expression of iNOS and TNF-α was observed in macrophages transduced with Wip1 RNA interference, while an increased expression of Arg-1 and CD206 was observed in macrophages transduced with Wip1 overexpressed vector, indicating that RAW264.7 macrophages could be transformed into M2 macrophages after Wip1 overexpression, and transformed into M1 macrophages by down-regulating Wip1. In addition, the E-cadherin mRNA level decreased and Vimentin and α-SMA increased in RTECs co-cultured with Wip1 overexpressed macrophages compared to the control group. CONCLUSION: Wip1 may participate in the pathophysiological process of renal tubulointerstitial fibrosis by transforming macrophages into the M2 phenotype.

Investigation on Temperature Behavior for a GaAs E-pHEMT MMIC LNA.

In order to investigate the temperature behavior for monolithic microwave integrated circuits (MMICs) under alpine conditions, the performance parameters of a 0.4-3.8 GHz gallium arsenide (GaAs) enhancement pseudomorphic high-electron-mobility transistor (E-pHEMT) low-noise amplifier (LNA) are tested at different temperatures. The typical temperatures of -39.2 °C, -32.9 °C, -25.3 °C, -11.3 °C, -4.9 °C, 0 °C and 23 °C are chosen as the alpine condition. The major performance indexes including the direct current (DC) characteristics, S-parameters, stability, radio frequency (RF) output characteristics, output third-order intersection point (OIP3) and noise figure (NF), which were inspected and analyzed in detail. The results show that the DC characteristics, small-signal gain (S21), RF output characteristics and NF all deteriorate with the rising temperature due to the decrease in two-dimensional electron gas mobility (µ). Contrary to this trend, the special design makes stability and OIP3 increase. For further application of this MMIC LNA under alpine conditions, several measures can be utilized to remedy performance degradation. This paper can provide some significant engineering value for the reliable design of MMICs.

[Evaluation of immune status of kidney transplant recipients by combined HLA-G5 and sCD30].

OBJECTIVE: to study the relationship between the expression of serum human leucocyte antigen-G5 (HLA-G5)/soluble CD30 (sCD30) and the function of renal graft in kidney transplant recipients and investigate the immune status of recipients with combined HLA-G5 and sCD30. METHODS: from January 2002 to November 2008, a total of 66 kidney transplant recipients in our centre were selected as subjects and divided into three groups: stable function of renal graft (n = 38), acute rejection (n = 15) and chronic rejection (n = 13). The expressions of serum HLA-G5 and sCD30 were detected. There were two different immune conditions with acute/chronic allograft rejection and normal renal graft in kidney transplant recipients as evaluated by combined HLA-G5 and sCD30. The sensitivity, specificity and critical value of the method were analyzed by the curve of receiver operating characteristic. RESULTS: the levels of HLA-G5 and sCD30 were significantly correlated with serum creatinine (r = -0.493, 0.691, both P < 0.01). Within the first year post-transplantation, the sensitivity was 78.6% and the specificity 85.7% when HLA-G5 critical value 82 microg/L and sCD30 critical value 12.2 microg/L. After one year post-transplantation: the sensitivity was 92.3% and the specificity 84.6% when HLA-G5 critical value 141 microg/L and sCD30 critical value 10.3 microg/L. CONCLUSION: the immune state of recipients are evaluated by combine HLA-G5 and sCD30 which may be a simple and valid method.

Effect of uremic serum on Th17/Treg cell balance and endoplasmic reticulum stress in rats.

BACKGROUND/AIMS: The imbalance of T helper 17 (Th17) and regulatory T (Treg) cells exists in the occurrence and development of various diseases. Endoplasmic reticulum stress (ERS) is an important self-protective cellular response to harmful stimuli, such as uremic environment. The objective of this study was to investigate the Th17/Treg cell balance and ERS in a uremic environment and analyze the relationship between them. METHODS: (1) The rat spleen lymphocytes were extracted and treated with thapsigargin (inducer of ERS) and sodium citrate. The proportion of Th17 and Treg cells were then detected. (2) The uremic serum-cultured lymphocytes were used and divided into three groups: non-uremic serum group, uremic serum group, and uremic serum + sodium citrate group. Afterward, the proportion of Th17/Treg cells and the expression of ERS-related proteins (GRP78 and CHOP) were detected. RESULTS: Thapsigargin had no significant effect on the proportion of Th17 cells within a limited concentration range, but it could reduce the proportion of Treg cells, sodium citrate had a negative influence on the deviation of Th17/Treg cells treated with thapsigargin. Uremic serum treatment reduced the proportion of Treg cells, resulting in an increase of the Th17/Treg ratio. However, sodium citrate had no influence on the deviation of Th17/Treg cells treated by uremic serum. Sodium citrate reduced the elevation of ERS-related proteins induced by uremic serum. CONCLUSIONS: Uremic serum can lead to the imbalance of Th17/Treg cells as well as ERS, suggesting that ERS is one of the mechanisms of the imbalance of Th17/Treg cells induced by uremic serum. Sodium citrate can inhibit ERS induced by uremic serum.

Farrerol alleviates high glucose-induced renal mesangial cell injury through the ROS/Nox4/ERK1/2 pathway.

Hyperproliferation and oxidative stress induced by hyperglycemia in mesangial cells plays crucial roles in the pathological process of diabetic nephropathy. Farrerol, isolated from rhododendron leaves, possesses broad anti-oxidative and anti-inflammatory properties towards several diseases, but its role in diabetic neuropathy remains unclear. The aim of this study was to evaluate the effects of farrerol in high glucose induced mesangial cell injury, and to explore underlying molecular mechanisms. Our results showed that high glucose in vitro conditions significantly stimulated cell proliferation, inflammatory cytokine secretion, extracellular matrix deposition, excessive oxidative stress, and NADPH oxidase activity in mesangial cells. Levels of NADPH oxidase 4 (Nox4) expression, ERK1/2 phosphorylation, and TGF-ß1/Smad2 activation were significantly induced by high glucose conditions in mesangial cells. Inversely, farrerol treatments at 40, 60, and 80 µM concentrations, dose-dependently alleviated this molecular damage by high glucose in mesangial cells. We also found that restoration of Nox4 expression abolished the protective effects of farrerol on high glucose-induced proliferation and reactive oxygen species generation. Furthermore, pretreatment with the Nox4 inhibitor diphenyliodonium or the ERK1/2 pathway inhibitor PD98059, displayed similar ameliorated effects of farrerol on high glucose-induced mesangial cell damage. Taken together, these data suggest that farrerol displays protective effects on high glucose induced mesangial cell injury, partly through the Nox4-mediated ROS/ERK1/2 signaling pathway. These observations may provide novel insights into the application of farrerol as a diabetic neuropathy treatment.

Citrate attenuates vascular calcification in chronic renal failure rats.

Vascular calcification (VC) is a major contributor of cardiovascular dysfunction in chronic renal failure (CRF). Citrate binds calcium and inhibits the growth of calcium crystals. This present study intends to evaluate the effect of citrate on VC in adenine-induced CRF rats. The rats were randomly divided into five groups: the control group, the citrate control group, model group, model rats with low-dose treatment of citrate (216 mg/kg) and model rats with high-dose treatment of citrate (746 mg/kg). The rats were euthanized at 5 weeks with their blood and aorta in detection. The results showed that serum level of blood urea nitrogen, serum creatinine, phosphorus, calcium, and related renal failure function marker were elevated in the model group. Furthermore, the aortic calcium accumulation and alkaline phosphatase activity were significantly increased in the model group compared with control groups. Additionally, hematoxylin-eosin staining results demonstrated that the vascular calcification in aorta is significantly increased in the model group. Finally, the expression of VC-related proteins including bone morphogenetic protein and osteocalcin were increased in the model group, whereas alpha-smooth muscle actin was decreased in the model group compared with the control group. However, treatment with citrate caused a reversal effect of all the above events in a dose-dependent manner. In conclusion, citrate may attenuate vascular calcification in adenine-induced CRF rats.

Sirt1 is essential for resveratrol enhancement of hypoxia-induced autophagy in the type 2 diabetic nephropathy rat.

Type 2 diabetic nephropathy (DN) is a serious end-stage kidney disease worldwide. Multiple studies demonstrate that resveratrol (RSV) has a beneficial effect on DN. However, whether RSV-induced improvement in kidney function in diabetes is due to the regulation of autophagy remains unclear. Here, we investigated the mechanisms underlying RSV-mediated protection against DN in diabetic rats, with a special focus on the role of NAD-dependent deacetylase sirtuin 1 (Sirt1) in regulating autophagy. We found that long-term RSV treatment in rats promoted Sirt1 expression and improved related metabolic levels in the diabetic kidney. Our study showed that, in cultured NRK-52E cells, Sirt1 knockdown inhibited the autophagy levels of proteins Atg7, Atg5, and LC3 and impaired the RSV amelioration of dysfunctional autophagy under hypoxic condition. Furthermore, exposed to 1% O2 over time induced autophagy dysfunction and apoptosis in NRK-52E cells, which could be improved by RSV treatment. Our data highlight the role of the Sirt1-mediated pathway in the effects of RSV on autophagy in vivo and in vitro, suggesting RSV could be a potential new therapy for type 2 DN.

Citrate Attenuates Adenine-Induced Chronic Renal Failure in Rats by Modulating the Th17/Treg Cell Balance.

Citrate is commonly used as an anticoagulant in hemodialysis for chronic renal failure (CRF) and for the regulation of the immune dysfunction in CRF patients. The objective of this study was to investigate the effect of citrate on the balance of T helper 17 (Th17) and regulatory T (Treg) cells in CRF. The levels of blood urea nitrogen (BUN) and serum creatinine (Scr) were significantly increased in the CRF model group compared to the control group, and were decreased in the citrate-treated groups. Citrate treatment inhibited the viability of Th17 cells while elevating the viability of Treg cells in CRF rats. Moreover, Th17-related cytokines significantly decreased while the Treg-related cytokines significantly increased with citrate treatment. Moreover, citrate had a negative influence on the deviation of Th17/Treg cells in CRF rats. Therefore, our study suggests that citrate had an anti-inflammatory effect on CRF through the modulation of the Th17/Treg balance.

Activation of AMPK by metformin inhibits TGF-ß-induced collagen production in mouse renal fibroblasts.

AIMS: To clarify whether activation of adenosine monophosphate-activated protein kinase (AMPK) by metformin inhibits transforming growth factor beta (TGF-ß)-induced collagen production in primary cultured mouse renal fibroblasts and further to address the molecular mechanisms. MAIN METHODS: Primary cultured mouse renal fibroblasts were stimulated with TGF-ß1 and the sequence specific siRNA of Smad3 or connective tissue growth factor (CTGF) was applied to investigate the involvement of these molecular mediators in TGF-ß1-induced collagen type I production. Cells were pre-incubated with AMPK agonist metformin or co-incubated with AMPK agonist metformin and AMPK inhibitor Compound C before TGF-ß1 stimulation to clarify whether activation of AMPK inhibition of TGF-ß1-induced renal fibroblast collagen type I expression. KEY FINDINGS: Our results demonstrate that TGF-ß1 time- and dose-dependently induced renal fibroblast collagen type I production; TGF-ß1 also stimulated Smad3-dependent CTGF expression and caused collagen type I generation; this effect was blocked by knockdown of Smad3 or CTGF. Activation of AMPK by metformin reduced TGF-ß1-induced collagen type I production by suppression of Smad3-driven CTGF expression. SIGNIFICANCE: This study suggests that activation of AMPK might be a novel strategy for the treatment of chronic kidney disease (CKD) partially by inhibition of renal interstitial fibrosis (RIF).

Sorafenib ameliorates renal fibrosis through inhibition of TGF-ß-induced epithelial-mesenchymal transition.

OBJECTIVE: This study was to investigate whether sorafenib can inhibit the progression of renal fibrosis and to study the possible mechanisms of this effect. METHODS: Eight-week-old rats were subjected to unilateral ureteral obstruction (UUO) and were intragastrically administered sorafenib, while control and sham groups were administered vehicle for 14 or 21 days. NRK-52E cells were treated with TGF-ß1 and sorafenib for 24 or 48 hours. HE and Masson staining were used to visualize fibrosis of the renal tissue in each group. The expression of α-SMA and E-cadherin in kidney tissue and NRK-52E cells were performed using immunohistochemistry and immunofluorescence. The apoptosis rate of NRK-52E cells was determined by flow cytometry analysis. The protein levels of Smad3 and p-Smad3 in kidney tissue and NRK-52E cells were detected by western blot analysis. RESULTS: HE staining demonstrated that kidney interstitial fibrosis, tubular atrophy, and inflammatory cell infiltration in the sorafenib-treated-UUO groups were significantly decreased compared with the vehicle-treated-UUO group (p<0.05). Masson staining showed that the area of fibrosis was significantly decreased in the sorafenib-treated-UUO groups compared with vehicle-treated-UUO group (p<0.01). The size of the kidney did not significantly increase; the cortex of the kidney was thicker and had a richer blood supply in the middle-dose sorafenib group compared with the vehicle-treated-UUO group (p<0.05). Compared with the vehicle-treated-UUO and TGF-ß-stimulated NRK-52E groups, the expression of a-SMA and E-cadherin decreased and increased, respectively, in the UUO kidneys and NRK-52E cells of the sorafenib-treated groups (p<0.05). The apoptotic rate of NRK-52E cells treated with sorafenib decreased for 24 hours in a dose-dependent manner (p<0.05). Compared with the vehicle-treated UUO and TGF-ß-stimulated NRK-52E groups, the ratio of p-Smad3 to Smad3 decreased in the sorafenib-treated groups (p<0.05). CONCLUSION: Our results suggest that sorafenib may useful for the treatment of renal fibrosis through the suppression of TGF-ß/Smad3-induced EMT signaling.

Inhibition of the K+ channel K(Ca)3.1 reduces TGF-ß1-induced premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells.

OBJECTIVE: K(Ca)3.1 channel participates in many important cellular functions. This study planned to investigate the potential involvement of K(Ca)3.1 channel in premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells. METHODS & MATERIALS: Rat mesangial cells were cultured together with TGF-ß1 (2 ng/ml) and TGF-ß1 (2 ng/ml) + TRAM-34 (16 nM) separately for specified times from 0 min to 60 min. The cells without treatment served as controls. The location of K(Ca)3.1 channels in mesangial cells was determined with Confocal laser microscope, the cell cycle of mesangial cells was assessed with flow cytometry, the protein and mRNA expression of K(Ca)3.1, α-smooth muscle actin (α-SMA) and fibroblast-specific protein-1 (FSP-1) were detected with Western blot and RT-PCR. One-way analysis of variance (ANOVA) and Student-Newman-Keuls-q test (SNK-q) were used to do statistical analysis. Statistical significance was considered at P<0.05. RESULTS: Kca3.1 channels were located in the cell membranes and/or in the cytoplasm of mesangial cells. The percentage of cells in G0-G1 phase and the expression of K(ca)3.1, α-SMA and FSP-1 were elevated under the induction of TGF-ß1 when compared to the control and decreased under the induction of TGF-ß1+TRAM-34 when compared to the TGF-ß1 induced (P<0.05 or P<0.01). CONCLUSION: Targeted disruption of K(Ca)3.1 inhibits TGF-ß1-induced premature aging, myofibroblast-like phenotype transdifferentiation and proliferation of mesangial cells.