Endothelial nitric oxide synthase regulation is altered in pancreas from cirrhotic rats

AIM： To determine whether biliary cirrhosis could induce pancreatic dysfunction such as modifications in endothelial nitric oxide synthase（eNOS） expression and whether the regulation of eNOS could be altered by the regulatory proteins caveolin and heat shock protein 90 （Hsp90）, as well as by the modifications of calmodulin binding to eNOS. METHODS： Immunoprecipitations and Western blotting analysis were performed in pancreas isolated from sham and cirrhotic rats. RESULTS： Pancreatic injury was minor in cirrhotic rats but eNOS expression importantly decreased with the length （and the severity） of the disease. Because coimmunoprecipitation of eNOS with both Hsp90 and caveolin similarly decreased in cirrhotic rats, eNOS activity was not modified by this mechanism. In contrast, drrhosis decreased the calmodulin binding to eNOS with a concomitant decrease in eNOS activity. CONCLUSION： In biliary cirrhosis, pancreatic injury is minor but the pancreatic nitric oxide （NO） production is significantly decreased by two mechanisms： a decreased expression of the enzyme and a decreased binding of calmodulin to eNOS.

Titanate nanofibers reduce Kruppel-like factor 2(KLF2)-eNOS pathway in endothelial monolayer:A transcriptomic study

Although titanate nanofibers(TiNFs)and titanate nanotubes(TiNTs)have been proposed as relatively biocompatible nanomaterials(NMs),there is currently lacking of systemic studies which investigated the toxicity of TiNFs and TiNTs to endothelium.In this study,we developed endothelial monolayer model by using cell culture inserts,and systemically investigated the toxicity of TiNFs and TiNTs by RNA-seq,with a focus on Kruppel-like factor(KLF)-mediated effects,since KLF are transcription factors(TF)involved in the regulation of vascular biology.It was shown that NMs did not significantly induce cytotoxicity despite substantial internalization.However,the expression of many KLF was altered,and Western blot further confirmed that NMs down-regulated KLF2 proteins.Ingenuity pathway analysis(IPA)revealed that NMs altered the expression of KLF2-targed genes,typically the genes involved in inflammatory responses.KLF2-related Gene Ontology(GO)terms and Kyoto Encyclopedia of Gene and Genomes(KEGG)pathways were also altered,and it should be noticed that NMs altered GO terms and KEGG pathways related with endothelial NO synthase(eNOS).This study further verified that NMs decreased intracellular NO and eNOS proteins.All the observed effects were more obvious for TiNFs compared with TiNTs.Combined,this study showed that TiNFs or TiNTs we re non-cytotoxic to endothelial monolayer model,but TiNFs and more modestly TiNTs decreased KLF2 leading to decreased eNOS proteins and NO production.Our data may provide novel understanding about the toxicity of TiNFs as well as other Ti-based NMs to endothelium.