Selenium binding protein 1 protects renal tubular epithelial cells from ferroptosis by upregulating glutathione peroxidase 4.

Ferroptosis is a form of programmed cell death involved in various types of acute kidney injury (AKI). It is characterized by inactivation of the selenoprotein, glutathione peroxidase 4 (GPX4), and upregulation of acyl-CoA synthetase long-chain family member 4 (ACSL4). Since urinary selenium binding protein 1 (SBP1/SELENBP1) is a potential biomarker for AKI, this study investigated whether SBP1 plays a role in AKI. First, we showed that SBP1 is expressed in proximal tubular cells in normal human kidney, but is significant downregulated in cases of AKI in association with reduced GPX4 expression and increased ACSL4 expression. In mouse renal ischemia-reperfusion injury (I/R), the rapid downregulation of SBP1 protein levels preceded downregulation of GPX4 and the onset of necrosis. In vitro, hypoxia/reoxygenation (H/R) stimulation in human proximal tubular epithelial (HK-2) cells induced ferroptotic cell death in associated with an acute reduction in SBP1 and GPX4 expression, and increased oxidative stress. Knockdown of SBP1 reduced GPX4 expression and increased the susceptibility of HK-2 cells to H/R-induced cell death, whereas overexpression of SBP1 reduced oxidative stress, maintained GPX4 expression, reduced mitochondrial damage, and reduced H/R-induced cell death. Finally, selenium deficiency reduced GPX4 expression and promoted H/R-induced cell death, whereas addition of selenium was protective against H/R-induced oxidative stress. In conclusion, SBP1 plays a functional role in hypoxia-induced tubular cell death. Enhancing SBP1 expression is a potential therapeutic approach for the treatment of AKI.

Effect of pulsed intravenous methylprednisolone with alternative low-dose prednisone on high-risk IgA nephropathy: a 18-month prospective clinical trial.

Full-dose prednisone (FP) regimen in the treatment of high-risk immunoglobulin A nephropathy (IgAN) patients, is still controversial. The pulsed intravenous methylprednisolone combined with alternative low-dose prednisone (MCALP) might have a more favorable safety profile, which has not been fully investigated. Eighty-seven biopsy-proven IgAN adult patients and proteinuria between 1 and 3.5 g/24 h after ACEI/ARB for at least 90 days were randomly assigned to 6-month therapy: (1) MCALP group: 0.5 g of methylprednisolone intravenously for three consecutive days at the beginning of the course and 3rd month respectively, oral prednisone at a dose of 15 mg every other day for 6 months. (2) FP group: 0.8-1.0 mg/kg/days of prednisone (maximum 70 mg/day) for 2 months, then tapered by 5 mg every 10 days for the next 4 months. All patients were followed up for another 12 months. The primary outcome was complete remission (CR) of proteinuria at 12 months. The percentage of CR at 12th and 18th month were similar in the MCALP and FP groups (51% vs 58%, P = 0.490, at 12th month; 60% vs 56%, P = 0.714, at 18th month). The cumulative dosages of glucocorticoid were less in the MCALP group than FP group (4.31 ± 0.26 g vs 7.34 ± 1.21 g, P < 0.001). The analysis of the correlation between kidney biopsy Oxford MEST-C scores with clinical outcomes indicated the percentages of total remission was similar between two groups with or without M1, E1, S1, T1/T2, and C1/C2. More patients in the FP group presented infections (8% in MCALP vs 21% in FP), weight gain (4% in MCALP vs 19% in FP) and Cushing syndrome (3% in MCALP vs 18% in FP). These data indicated that MCALP maybe one of the choices for IgAN patients with a high risk for progression into ESKD.Trial registration: The study approved by the Chinese Clinical Trial Registry (registration date 13/01/2018, approval number ChiCTR1800014442, https://www.chictr.org.cn/ ).

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.

Growth and carbohydrate dynamic of perennial ryegrass seedlings during PEG-simulated drought and subsequent recovery.

Due to the increasing occurrence of drought events, drought recovery has become equally important as drought resistance for long-term growth and survival of plants. However, information regarding the mechanism that controls growth recovery of herbaceous perennials is not available. In this study, perennial ryegrass (Lolium perenne) was rewatered after eight-day exposure to three drought intensities simulated by polyethylene glycol-6000. The growth, nonstructural carbohydrates (NSC, i.e. sucrose, glucose, fructose and starch), shoot δ13C, and activities of enzymes for sucrose conversion were monitored for 24 days after rewatering, allowing investigation of the dynamic of NSCs and its relation with growth in the recovery phase. In response to drought, growth and NSC content decreased mainly in shoot rather than root, and the total dry matter was negatively correlated to shoot δ13C. After rewatering, the growth of drought-treated groups still lagged behind that of control (CK) group for more than 16 days, but it was no longer correlated to shoot δ13C, suggesting that the limited growth is caused by non-stomatal factors related to photosynthesis. On day 24 after rewatering, the final growth of drought-treated groups caught up or even exceeded that of CK group, and was accompanied by higher dry weight root to shoot ratio (R/S) and root NSC content, which may facilitate water and nutrient acquisition and emergency of new tillers, respectively. During drought and subsequent recovery, the variation of R/S and root NSC content mainly attributed to root acid invertase rather than leaf sucrose phosphate synthase activity.

Protective effects of GPR120 agonist-programmed macrophages on renal interstitial fibrosis in unilateral ureteral obstruction (UUO) rats.

Macrophages in the kidney play different roles in renal interstitial fibrosis (RIF) depending on their phenotypes. M2 phenotype macrophages are believed to protect the kidney against RIF. Free fatty acid receptor GPR120 is expressed in macrophages, and its activation induces macrophage transition to M2 phenotype. In this study, the effects of GPR120 agonist-programmed macrophages on RIF were investigated. The peritoneal macrophages collected from rats were incubated with GPR120 agonist TUG891 in vitro for 24 h, and then they were transplanted autologously to the kidney with ureteral obstruction by intrarenal injection for 7 days on the same day following unilateral ureteral obstruction (UUO) operation. RIF was identified by Masson trichrome histological staining, and the expression of RIF-related proteins was analyzed by immunohistochemistry and western blot. It was observed that TUG891-programmed macrophages up-regulated the expression of CD206 and arginase-1 while the expression of interleukin-6 and tumor necrosis factor-α were down-regulated. RIF in rats was significantly increased following UUO, which was markedly alleviated by TUG891-programmed macrophages but not untreated macrophages. TUG891-programmed macrophages inhibited the abnormal expression of TGF-ß1 and SMAD2. The abnormal expression of epithelial-mesenchymal transition (EMT)-related proteins including vimentin, α-SMA and ß-catenin was also significantly decreased in rats with transplantation of TUG891-programmed macrophages as compared to UUO rats. This study suggests that autologous administration of peritoneal macrophages programmed in vitro by GPR120 agonist to kidney has a protective effect against RIF following UUO.

Correlation of increased Th17/Treg cell ratio with endoplasmic reticulum stress in chronic kidney disease.

To investigate the relationship between the regulatory immune network and endoplasmic reticulum stress (ERS) in patients with different stages of chronic kidney disease (CKD).A total of 91 patients diagnosed with CKD were divided into different groups according to the stage of disease and treatment with hemodialysis (HD) or peritoneal dialysis (PD). Routine blood and biochemical tests were performed in patients in the different CKD groups and in healthy controls (n = 20). The frequencies of T helper type 17 (Th17) and regulatory T (Treg) cells in the overall T cell population were measured by flow cytometric analysis. Levels of Th17 cell (IL-17) and Treg cell (IL-10) cytokines and the ERS markers CCAAT-enhancer-binding protein homologous protein (CHOP) and glucose-regulated protein 78 (GRP78) were measured by enzyme-linked immunosorbent assay in serum samples collected from controls and patients. Correlations between each parameter and serum creatinine were analyzed by Spearman rank correlation and regression test.CKD stage showed a positive correlation with serum creatinine level, and increased and decreased percentages of Th17 and Treg cells, respectively, reflected in an increased Th17/Treg cell ratio. Consistent with this, CKD stage was positively correlated with serum concentrations of IL-17 and negatively correlated with serum IL-10 levels. Moreover, serum levels of CHOP and GRP78 increased with advancing CKD stage. These correlations were most pronounced in patients in the CKD5 group, who also had the poorest response to HD and PD treatment, compared with CKD5 patients in the nondialysis group. Correlation analysis showed that serum levels of CHOP and GRP78 were independently and positively correlated with the ratio of Th17/Treg cells.We have found that an increased Th17/Treg cell ratio and increased serum levels of ERS markers correlate with the progression of CKD. Our results indicate that the interplay between regulation of the immune network and management of ERS is closely associated with the pathogenesis of CKD. Although HD and PD treatment manage chronic kidney conditions and prevent further deterioration of renal function, they have limited effects on improving the immune disorder and relieving ERS. Our study suggests a potential new direction for development of therapeutic strategies in CKD.

Epithelial C5aR1 Signaling Enhances Uropathogenic Escherichia coli Adhesion to Human Renal Tubular Epithelial Cells.

Recent work in a murine model of ascending urinary tract infection has suggested that C5a/C5aR1 interactions play a pathogenic role in the development of renal infection through enhancement of bacterial adhesion/colonization to renal tubular epithelial cells (RTECs). In the present study, we extended these observations to human. We show that renal tubular epithelial C5aR1 signaling is involved in promoting uropathogenic Escherichia coli (UPEC) adhesion/invasion of host cells. Stimulation of primary cultures of RTEC with C5a resulted in significant increases in UPEC adhesion/invasion of the RTEC. This was associated with enhanced expression of terminal α-mannosyl residues (Man) (a ligand for type 1 fimbriae of E. coli) in the RTEC following C5a stimulation. Mechanism studies revealed that C5aR1-mediated activation of ERK1/2/NF-κB and upregulation of proinflammatory cytokine production (i.e., TNF-α) is at least partly responsible for the upregulation of Man expression and bacterial adhesion. Clinical sample studies showed that C5aR1 and Man were clearly detected in the renal tubular epithelium of normal human kidney biopsies, and UPEC bound to the epithelium in a d-mannose-dependent manner. Additionally, C5a levels were significantly increased in urine of urinary tract infection patients compared with healthy controls. Our data therefore demonstrate that, in agreement with observations in mice, human renal tubular epithelial C5aR1 signaling can upregulate Man expression in RTEC, which enhances UPEC adhesion to and invasion of RTEC. It also suggests the in vivo relevance of upregulation of Man expression in renal tubular epithelium by C5a/C5aR1 interactions and its potential impact on renal infection.

C5aR1 promotes acute pyelonephritis induced by uropathogenic E. coli.

C5a receptor 1 (C5aR1) is a G protein-coupled receptor for C5a and also an N-linked glycosylated protein. In addition to myeloid cells, C5aR1 is expressed on epithelial cells. In this study, we examined the role of C5aR1 in bacterial adhesion/colonization of renal tubular epithelium and addressed the underlying mechanisms of this role. We show that acute kidney infection was significantly reduced in mice with genetic deletion or through pharmacologic inhibition of C5aR1 following bladder inoculation with uropathogenic E. coli (UPEC). This was associated with reduced expression of terminal α-mannosyl residues (Man; a ligand for type 1 fimbriae of E. coli) on the luminal surface of renal tubular epithelium and reduction of early UPEC colonization in these mice. Confocal microscopy demonstrated that UPEC bind to Man on the luminal surface of renal tubular epithelium. In vitro analyses showed that C5a stimulation enhances Man expression in renal tubular epithelial cells and subsequent bacterial adhesion, which, at least in part, is dependent on TNF-α driven by C5aR1-mediated intracellular signaling. Our findings demonstrate a previously unknown pathogenic role for C5aR1 in acute pyelonephritis, proposing a potentially novel mechanism by which C5a/C5aR1 signaling mediates upregulation of carbohydrate ligands on renal tubules to facilitate UPEC adhesion.

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.

Anti-Double-Stranded DNA IgG Participates in Renal Fibrosis through Suppressing the Suppressor of Cytokine Signaling 1 Signals.

Suppressor of cytokine signaling 1 (SOCS1) participates in renal fibrosis by downregulating Janus kinase 2 (JAK2)/signal transducer and activator of transcription 1 (STAT1)-mediated cytokine signaling. Recently, it was found that anti-double-stranded DNA (dsDNA) IgG induces the synthesis of profibrotic cytokines by renal cells. To explore the potential effect of anti-dsDNA IgG on SOCS1-mediated renal fibrosis, kidney tissues were collected from patients with lupus nephritis (LN) as well as MRL/lpr lupus-prone mice. The SOCS1 expression was evaluated in tissue samples. In addition, SCID mice were injected with anti-dsDNA IgG, followed by evaluation of SOCS1 levels. Renal resident cells were cultured in vitro, receiving the stimulation of anti-dsDNA IgG and then the measurement of SOCS1, JAK2, STAT1α, and profibrotic cytokines. Moreover, the binding of anti-dsDNA IgG to SOCS1 kinase inhibitory region (KIR) peptide was analyzed by surface plasmon resonance. We found that SOCS1 expression was inhibited, but JAK2/STAT1 activation was prominent in the kidney tissues of patients with LN, MRL/lpr mice, or anti-dsDNA IgG-injected SCID mice. The cultured renal cells also showed SOCS1 downregulation, JAK2/STAT1 activation, and profibrotic cytokine promotion upon anti-dsDNA IgG stimulation. Surprisingly, anti-dsDNA IgG showed high affinity to KIR peptide and competed with JAK2 loop for KIR. Additionally, a DNA-mimicking peptide (ALW) blocked the binding of anti-dsDNA IgG to KIR, and even partially abrogated the activation of JAK2/STAT1α signals and the expression of profibrotic cytokines in SCID mice. In conclusion, anti-dsDNA IgG downregulates SOCS1 expression, activates JAK2/STAT1 signals, and contributes to renal fibrosis; its peptide blockade may restore the SOCS1 inhibitory effect on the production of profibrotic cytokine, and finally ameliorate renal fibrosis in LN.

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.

Sodium Citrate Inhibits Endoplasmic Reticulum Stress in Rats with Adenine-Induced Chronic Renal Failure.

BACKGROUND/AIMS: Endoplasmic reticulum stress (ERS) is an important self-protective cellular response to harmful stimuli that contribute to various diseases, including chronic renal failure (CRF). Sodium citrate plays an important role in antioxidant and cellular immunity, but whether it improves ERS in CRF is unclear. METHODS: The rats were randomly divided into five groups: the control group, the sodium citrate control group, the model group, model rats with low dose sodium citrate (216 mg/kg), and model rats with a high dose of sodium citrate (746 mg/kg). The rats were euthanized at 6, 8, 12, and 16 weeks with their blood and renal tissue in detection. RESULTS: The increased concentrations of blood urea nitrogen and serum creatinine in the model group were significantly decreased by sodium citrate treatment. Hematoxylin-eosin and Masson staining showed that sodium citrate treatment apparently improved renal pathological changes in CRF rats. Western blot analysis showed that sodium citrate treatment decreased the protein levels of transforming growth factor-beta 1 and collagen type IV, which were increased in model rats. Moreover, immunohistochemical staining demonstrated that sodium citrate could effectively reduce the protein expression of glucose-regulated protein 78 kDa and CCAAT/enhancer-binding protein homologous protein in the model rats, which was consistent with western blot results. Additionally, the high dose of sodium citrate had a stronger protective effect in CRF rats than the low dose of sodium citrate. CONCLUSIONS: Sodium citrate has a protective effect on CRF through its effects on ERS.

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.

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.

Uremic anorexia and ghrelin expression in the amygdala.

BACKGROUND/AIMS: Ghrelin can act as a signal for mealtime hunger and meal initiation. Amygdala is indispensable in appetitive behavior motivated by learned emotions. This study was to investigate the alteration of ghrelin in the amygdala of rats with chronic renal failure (CRF) and its relation with uremic anorexia. METHODS: SD rats were randomly classified into CRF group and control group (n=16 per group). The CRF model was constructed using 5/6 nephrectomy. When plasma creatinine (PCr) and blood urea nitrogen (BUN) in the CRF group were twice more than the normal level, food intake (g/24h) was measured and then all rats were killed for detection of ghrelin protein expression in the amygdala using immunohistochemical analysis and mRNA expression using RT-PCT. Statistics was conducted with one-way analysis of variance, Student-Newman-Keuls-q test and correlation analysis. RESULTS: By the 8th week after the surgery, the BUN and PCr of CRF rats exceeded double the normal level, and their food intake was obviously decreased compared with the controls (P<0.05). The protein and mRNA expression of ghrelin in the amygdala of CRF group were significantly reduced, and there was a positive correlation between this reduction and the decrease in food intake (P<0.05). CONCLUSION: The reduction of amygdala's ghrelin in CRF rats may be associated with uremic anorexia.