CircGAB1 Facilitates Podocyte Injury Through Sponging miR-346 and Activating MAPK6 in Diabetic Nephropathy.

BACKGROUND: Podocyte injury is very important process in diabetic nephropathy (DN) progression. Circular RNA (circRNA) takes part in regulating the advancement of DN. Herein, we explored the role and mechanism of circGAB1 in DN progression. METHODS: The abundances of circGAB1, microRNA-346 (miR-346) and mitogen-activated protein kinase 6 (MAPK6) were detected by qRT-PCR in DN serum samples and podocyte HGPC. Moreover, cell viability and apoptosis were determined using CCK8 assay and flow cytometry. Also, the protein levels of MAPK6, proliferation-related markers and apoptosis-related markers were analyzed by western blot. ELISA assay was used to measure the levels of inflammatory factors, and corresponding kits were used to detect the levels of oxidative stress-related markers. The relationship between miR-346 and circGAB1 or MAPK6 was distinguished by dual-luciferase reporter assay. RESULTS: CircGAB1 expression was increased in DN serum samples and HG-treated HGPC cells. CircGAB1 knockdown inhibited HG-induced apoptosis, inflammatory response and oxidative stress in HGPC cells. In terms of mechanism, circGAB1 sponged miR-346, and miR-346 targeted MAPK6. The inhibition effect of circGAB1 knockdown on HG-induced podocyte injury could be reversed by miR-346 inhibitor. Moreover, miR-346 overexpression repressed HG-induced podocyte injury by targeting MAPK6. CircGAB1 served as miR-346 sponge to positively regulate MAPK6. CONCLUSION: CircGAB1 contributed to podocyte injury through mediating miR-346/MAPK6 axis, suggesting that circGAB1 might promote DN progression.

Relaxin Attenuates Contrast-Induced Human Proximal Tubular Epithelial Cell Apoptosis by Activation of the PI3K/Akt Signaling Pathway In Vitro.

Background. Contrast-induced acute kidney injury (CI-AKI) is one of the main causes of iatrogenic acute kidney injury (AKI); however, therapeutic strategies for AKI remain limited. This study aims to explore the effect of relaxin (RLX) on contrast-induced HK-2 apoptosis and its underlying mechanisms. Methods. Renal tubular epithelial cells (HK-2) were incubated either with or without ioversol, human H2 relaxin, and LY294002 (the inhibitor of the PI3K/Akt signal pathway). Cell viability was evaluated with a CCK-8 assay. Apoptotic morphologic alterations were observed using the Hoechst 33342 staining method. Apoptosis was detected with Annexin V staining. Western blot analysis was employed to measure the expression of pAkt (S473), Akt, cleaved caspase-3, Bcl-2, Bax, and actin proteins. Results. Ioversol reduced the viability of HK-2 cells. Western blotting results revealed decreased expression of phosphorylated Akt in cells treated with ioversol. The activities of caspase-3 and Bax protein increased, while the expression of Bcl-2 protein decreased. As a result, the Bax/Bcl-2 ratio increased after treatment with ioversol. These effects were reversed when HK-2 cells were cotreated with RLX. However, with preadministration of PI3K/Akt pathway inhibitor LY294002, the effect of RLX was blocked. Conclusion. Our study demonstrates that relaxin attenuates ioversol induced cell apoptosis via activation of the PI3K/Akt signaling pathway, suggesting that RLX might play a protective role in the treatment of CI-AKI.

Relaxin attenuates aristolochic acid induced human tubular epithelial cell apoptosis in vitro by activation of the PI3K/Akt signaling pathway.

Aristolochic acid nephropathy remains a leading cause of chronic kidney disease (CKD), however few treatment strategies exist. Emerging evidence has shown that H2 relaxin (RLX) possesses powerful antifibrosis and anti-apoptotic properties, therefore we aimed to investigate whether H2 relaxin can be employed to reduce AA-induced cell apoptosis. Human proximal tubular epithelial (HK-2) cells exposed to AA-I were treated with or without administration of H2 RLX. Cell viability was examined using the WST-8 assay. Apoptotic morphologic alterations were observed using the Hoechst 33342 staining method. Apoptosis was detected using flow cytometry. The expression of caspase 3, caspase 8, caspase 9, ERK1/2, Bax, Bcl-2, and Akt proteins was determined by Western blot. Co-treatment with RLX reversed the increased apoptosis observed in the AA-I only treated group. RLX restored expression of phosphorylated Akt which found to be decreased in the AA-I only treated cells. RLX co-treatment led to a decrease in the Bax/Bcl-2 ratio as well as the cleaved form of caspase-3 compared to the AA-I only treated cells. This anti-apoptotic effect of RLX was attenuated by co-administration of the Akt inhibitor LY294002. The present study demonstrated H2 RLX can decrease AA-I induced apoptosis through activation of the PI3K/Akt signaling pathway.

Relaxin Inhibits High Glucose-Induced Matrix Accumulation in Human Mesangial Cells by Interfering with TGF-ß1 Production and Mesangial Cells Phenotypic Transition.

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD). DN is characterized by glomerular extracellular matrix accumulation, mesangial expansion, basement membrane thickening, and renal interstitial fibrosis. To date, mounting evidence has shown that H2 relaxin possesses powerful antifibrosis properties; however, the mechanisms of H2 relaxin on diabetic nephropathy remain unknown. Here, we aimed to explore whether H2 relaxin can reduce production of extracellular matrix (ECM) secreted by human mesangial cells (HMC). HMC were exposed to 5.5 mM glucose (NG) or 30 mM glucose (HG) with or without H2 relaxin. Fibronectin (FN) and collagen type IV levels in the culture supernatants were examined by solid-phase enzyme-linked immunoadsorbent assay (ELISA). Western blot was used to detect the expression of α-smooth muscle actin (α-SMA) protein. Quantitative polymerase chain reaction (qPCR) method was employed to analyze transforming growth factor (TGF)-ß1 mRNA expression. Compared with the normal glucose group, the levels of fibronectin and collagen type were markedly increased after being cultured in high glucose medium. Compared with the high glucose group, remarkable decreases of fibronectin, collagen type IV, α-smooth muscle actin, and TGF-ß1 mRNA expression were observed in the H2 relaxin-treated group. The mechanism by which H2 relaxin reduced high glucose-induced overproduction of ECM may be associated with inhibition of TGF-ß1 mRNA expression and mesangial cells' phenotypic transition. H2 relaxin is a potentially effective modality for the treatment of DN.

Mechanism of kidney injury caused by bevacizumab in rats.

OBJECTIVE: We investigate kidney injury caused by high dose bevacizumab to uncover the possible mechanisms involving in this process. METHODS: Forty rats were divided into four groups: cisplation group (treated with 1 mg/kg cisplation), Bev-high group (treated with 5 mg/kg bevacizumab); Bev-low group (treated with 2.5 mg/kg bevacizumab) and control group (treated with saline). The urine microalbumin, serum cystatin C, blood urea nitrogen and serum creatinine were detected in the four group rats, respectively. The immunoglobulin of IgG, IgA and IgM and protein of VEGF (vascular endothelial growth factor) and nephrin were detected by immunohistochemical methods. RESULTS: All the levels of microalbumin, cystatin C, serum creatinine and blood urea nitrogen in Bev-high group were significantly higher than those in normal control group (P < 0.05). The cystatin C was much more increased in kidney Bev-high group than cisplatin and Bev-low groups (P < 0.05). The light microscope showed a normal glomerular morphology in the four groups, while the electronic microscopy showed the podocytes were extensively fused in cisplatin group and Bev-high group. The two groups were found IgG and IgM deposition as well. The VEGF in kidney amples were down regulated in high dose bevacizumab group, whereas the nephrin and IgA showed no significant expression changes at all. CONCLUSION: Bevacizumab increases the risk of injury in glomerular filtration barrier in a dose dependent model. The injury may not only associate with the rising level of proteinuria but also with podocyte-dependent membrane structures.

[Cyst puncture aspiration in 40 cases of abdominal echinococcosis].

OBJECTIVE: To evaluate the efficacy of cyst puncture aspiration in treating abdominal echinococcosis. METHOD: A retrospective analysis was performed in 40 cases of abdominal echinococcosis with formation of isolated single cyst in close adhesion with the abdominal wall, for which cyst puncture aspiration was carried out under ultrasound guidance. RESULTS: No death occurred in these patients and only 15 developed mild fever. The days for antibiotic use, jaundice resolution, bile secretion, time of extubation and hospital stay were 2.88+/-0.65, 3.50+/-0.71, 4.25+/-0.96, 5.38+/-0.98 and 9.35+/-1.08 days, respectively. Ultrasound examination in the follow-up showed no relapse in these patients, with the time of the residue adhesive cyst closure and calcification of 4.50+/-1.13 and 13.90+/-2.38 months, respectively. CONCLUSION: Cyst puncture aspiration under ultrasound guidance produces good therapeutic effects on abdominal echinococcosis with isolated single cyst closely adhering to the abdominal wall.