This study aims to investigate the role of Notch pathway in the renal ischemia/reperfusion injury (IRI)-associated inflammation and apoptosis. Materials and methods: Male Sprague-Dawley rats were divided into three groups: normal saline (NS)-treated sham rats, NS-treated ischemia/reperfusion (I/R) rats, and N- [N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT) (a γ-secretase inhibitor) treated I/R rats. I/R rat model underwent nephrectomy of the right kidney and was subjected to 60 min of left renal pedicle occlusion followed by 24 h, 48 h, and 72 h of reperfusion, respectively. The levels of creatinine, urea nitrogen (BUN), interleukin (IL)-6, tumor necrosis factor (TNF)-α in serum samples and urinary N-acety-β-D-glucosaminidase (NAG) were assayed. Histological examinations were performed. The protein expression of Notch2, hairy/enhancer of split 1 (hes-1), NF-κB2, monocyte chemoattractant protein (MCP)-1, B-cell lymphoma 2 (bcl-2), and bcl-2-associated X (bax) were detected and the degree of apoptosis of tubular cells was evaluated. Results: Renal IR induced severe tubular damage, caused significant increases in the Scr, BUN, IL-6, TNF-α, urinary NAG, Notch2, hes-1, NF-κB2, MCP-1, ratio of tubule cells apoptosis, and reduction in the ratio of bcl-2 to bax. However, DAPT treatment significantly reduced the level of Scr, BUN, IL-6, TNF-α, and NAG. Thus, I/R activates Notch2/hes-1 signaling and DAPT treatment can ameliorate the severity of tubular damage after renal IRI, lower the expression of NF-κB2, MCP-1, and bax protein, increase the expression of bcl-2 protein, and reduce the ratio of terminal 2-deoxyuridine 5-triphosphate nick end-labeling-positive cells. Conclusion: Notch signaling plays an important role in the renal IRI-associated inflammation and apoptosis. DAPT can protect against IRI through partly suppressing inflammation and apoptosis, which could constitute a new target for AKI.

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The molecular mechanism linking aldosterone and endothelin-1 in the development of diabetic nephropathy has not been completely elucidated. Here, we provide evidence showing that streptozotocin-induced diabetic rats have significantly increased aldosterone and endothelin-1 in the kidney tissue and markedly decreased expression of Dot1a and Af9. Blocking aldosterone with spironolactone significantly reduced proteinuria, glomerulosclerosis, tubulointerstitial injury and endothelin-1 expression, and significantly increased Dot1a and Af9 expression. Increasing Dot1a and Af9 expression by spironolactone or by stable transfection led to impaired endothelin-1 expression in NRK-52 cells. In contrast, downregulation of Dot1a and Af9 by aldosterone in NRK-52E cells caused upregulation of endothelin-1. Genetic inactivation of Dot1l, which encodes Dot1a, in Aqp2-expressing principal cells of mouse kidney impaired association of Dot1a and H3 dimethyl K79 with the specific subregions of endothelin-1 promoter, and upregulates endothelin-1 mRNA and protein expression. Our data suggest that Dot1a and Af9 repress endothelin-1 in vitro and in vivo. Excessive aldosterone induces kidney injury, in part possibly by downregulating Dot1a and Af9, and thus relieving Dot1a-Af9-mediated repression to increase endothelin-1 transcription. Spironolactone ameliorates kidney injury in Streptozotocin-induced diabetic rats, possibly by restoring Dot1a-Af9-mediated repression to reduce endothelin-1 expression. Therefore, Dot1a and Af9 as aldosterone-downregulated targets are negative regulators of endothelin-1 transcription in vitro and in vivo, and may be considered as new potential therapeutic targets of kidney injury in diabetes.

Background/Aims: Anticoagulation in hemodialysis (HD) patients at high risk of bleeding remains an intractable problem. Simulating endothelial cells by releasing anticoagulant on the membrane may be a promising alternative. Methods: We modified a polyacrylonitrile (PAN) dialyzer by loading argatroban into its membrane and verified its anticoagulation efficiency and its influence on coagulation markers such as activated partial thromboplastin time (aPTT), D-dimer and thrombin-antithrombin complex (TAT) in an animal HD model. Results: All HD sessions with the argatroban dialyzer were completed successfully with either no or minimal fiber clotting. D-dimer was lower in the argatroban group than in the PAN group; TAT and aPTT values were similar in the two groups, which suggests better anticoagulation and a similar influence on the coagulation system. Conclusion: HD with the argatroban dialyzer is feasible, safe and simple, and could be used in patients at high risk of bleeding.