Tissue kallikrein mediates pro-inflammatory pathways and activation of protease-activated receptor-4 in proximal tubular epithelial cells.

published_or_final_versio

N-Acetyl-seryl-aspartyl-lysyl-proline Alleviates Renal Fibrosis Induced by Unilateral Ureteric Obstruction in BALB/C Mice

To expand the armamentarium of treatment for chronic kidney disease (CKD), we explored the utility of boosting endogenously synthesized N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), which is augmented by inhibition of the angiotensin converting enzyme. Male BALB/c mice underwent unilateral ureteral ligation (UUO) or sham operation and received exogenously administered Ac-SDKP delivered via a subcutaneous osmotic minipump or Captopril treatment by oral gavage. Seven days after UUO, there were significant reductions in the expression of both collagen 1 and collagen 3 in kidneys treated with Ac-SDKP or Captopril, and there was a trend towards reductions in collagen IV, alpha-SMA, and MCP-1 versus control. However, no significant attenuation of interstitial injury or macrophage infiltration was observed. These findings are in contrary to observations in other models and underscore the fact that a longer treatment time frame may be required to yield anti-inflammatory effects in BALB/c mice treated with Ac-SDKP compared to untreated mice. Finding an effective treatment regimen for CKD requires fine-tuning of pharmacologic protocols.published_or_final_versio

Semi-individualised Chinese medicine treatment as an adjuvant management for diabetic nephropathy: a pilot add-on, randomised, controlled, multicentre, open-label pragmatic clinical trial

published_or_final_versio

Human Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Prevent Adriamycin Nephropathy in Mice

published_or_final_versio

Thrombin induces Epithelial-Mesenchymal Transition through the activation of PAR-1 in Tubular Epithelial Cells

Saturday Poster - Extracellular Matrix Biology, Fibrosis, and Cell Adhesion - 2: no. SA-PO414BACKGROUND: Fibrin deposition is commonly observed in tubulointerstitial injury of chronic kidney diseases. Recent studies have suggested that local activation of thrombin contributes to renal fibrosis. However, the effect of thrombin on tubular cells is not fully understood. Since epithelial-mesenchymal transition (EMT) is an important mechanism of renal tubulointerstitial fibrosis, we investigated whether thrombin plays a role in tubular EMT and dissected the underlying mechanism. METHODS: Rat kidney tubular epithelial cells (NRK52E) were treated with thrombin (1-4U/ml) for 72 h and were examined for the expression of EMT and profibrotic markers. To determine the potential role of protease activated receptor (PAR) in tubular EMT, selective PAR antagonists, SCH7979 for PAR-1 and tcY-NH2 for PAR-4 were co-incubated with thrombin. RESULTS: After 72-h treatment, cells underwent a transition from an epithelial to a mesenchymal phenotype as evidenced by reduced expression of E-cadherin, and increased expression of α-smooth muscle actin in a dose-dependent manner. Expression of snail, the known inducer of EMT, was also upregulated by thrombin. Blockade of PAR-1, but not PAR-4 partially restored the altered expression of thrombin-induced EMT markers. Besides, thrombin also stimulated the expression of profibrotic growth factors (TGFβ1 and CTGF) and extracellular matrix (ECM) proteins (fibronectin and collagen IV). The induction of TGFβ1 and collagen IV were suppressed by PAR-1 antagonist; while the induction of fibronectin was inhibited by both PAR-1 and PAR-4 antagonists. CONCLUSIONS: Our data demonstrated that thrombin promoted EMT and increased the production of profibrotic factors and ECM proteins in tubular epithelial cells. These effects were partially mediated by PAR-1 and, to a lesser extent, PAR-4. These results suggest that modulation of PAR signaling may provide a potential therapeutic strategy for the treatment of renal fibrosis. Fund support: Research Grants Council of Hong Kong (GRF grant number 7796/11M) and Small Project Funding (project code 201309176032) from the University of Hong Kong.link_to_OA_fulltex

Dedifferentiation-Reprogrammed Mesenchymal Stem Cells with Improved Therapeutic Potential in Diabetic Nephropathy

Poster Session: Apoptosis, Proliferation, Autophagy, Cell Senescence, Cell Transformatio

Spleen Tyrosine Kinase Inhibitor Ameliorates Tubular Inflammation in IgA Nephropathy.

Poster session: Pathologic Mechanism

Kallistatin protects against diabetic nephropathy in db/db mice by suppressing AGE-RAGE-Induced oxidative stress

Thursday Poster - Diabetes Mellitus and Obesity: Basic-Experimental - 1: no. TH-PO357BACKGROUND: Kallistatin is a serine protease inhibitor that exerts anti-inflammatory Anti-apoptotic and anti-oxidative effects in regulating cellular dysfunction. As oxidative stress plays a critical role in the pathogenesis of diabetic nephropathy, we aim to investigate the effect and mechanisms of kallistatin gene transfer on diabetic renal injury in the db/db mouse model of type 2 diabetes. METHODS: Plasmid with kallistatin gene was injected into the kidney of db/db mice using ultrasound-mediated microbubble-inducible gene transfer. The therapeutic potential of kallistatin in diabetic kidney was evaluated by histopathology, renal function, oxidative and fibrotic pathways. RESULTS: Kallistatin expression was induced in tubules of kidney after gene transfer compared with mice treated with empty plasmid. In db/db mice, kallistatin overexpression reduced serum creatinine and BUN levels, ameliorated glomerulosclerosis and tubulointerstitial injury and attenuated renal fibrosis by inhibiting TGF-β signaling and the downstream plasminogen activator inhibitor-1 and type IV collagen expression. Furthermore, kallistatin gene transfer significantly attenuated elevated oxidative stress in db/db mice as evidenced by suppressed levels of Nox4 and the oxidative marker (8-OHdG and MDA) in diabetic renal tissue. Finally, kallistatin inhibited expression of RAGE in both diabetic kidney and AGE-stimulated cultured proximal tubular epithelial cells, reflecting an anti-oxidative mechanism via AGE/RAGE axis. CONCLUSIONS: Our results suggest a renoprotective role of kallistatin against progression of diabetic nephropathy via anti-oxidative properties. Kallistatin reduced AGE-RAGE induced Nox4 expression, leading to suppression of oxidative stress and TGF-β-mediated renal fibrosis. Funding: Research Grants Council of Hong Kong (GRF grant number 7796/11M) and the National Basic Research Program of China 973 program no. 2012CB517600 (no 2012CB517606)

Kallistatin protects against diabetic nephropathy in db/db mice by suppressing AGE-RAGE-induced oxidative stress

Kallistatin is a serine protease inhibitor with anti-inflammatory, anti-angiogenic, and anti-oxidative properties. Since oxidative stress plays a critical role in the pathogenesis of diabetic nephropathy, we studied the effect and mechanisms of action of kallistatin superinduction. Using ultrasound-microbubble-mediated gene transfer, kallistatin overexpression was induced in kidney tubules. In db/db mice, kallistatin overexpression reduced serum creatinine and BUN levels, ameliorated glomerulosclerosis and tubulointerstitial injury, and attenuated renal fibrosis by inhibiting TGF-beta signaling. Additionally, downstream PAI-1 and collagens I and IV expression were reduced and kallistatin partially suppressed renal inflammation by inhibiting NF-kappaB signaling and decreasing tissue kallikrein activity. Kallistatin lowered blood pressure and attenuated oxidative stress as evidenced by suppressed levels of NADPH oxidase 4, and oxidative markers (nitrotyrosine, 8-hydroxydeoxyguanosine, and malondialdehyde) in diabetic renal tissue. Kallistatin also inhibited RAGE expression in the diabetic kidney and AGE-stimulated cultured proximal tubular cells. Reduced AGE-induced reactive oxygen species generation reflected an anti-oxidative mechanism via the AGE-RAGE-reactive oxygen species axis. These results indicate a renoprotective role of kallistatin against diabetic nephropathy by multiple mechanisms including suppression of oxidative stress, anti-fibrotic and anti-inflammatory actions, and blood pressure lowering.Kidney International advance online publication, 4 November 2015; doi:10.1038/ki.2015.331