title: Upregulation of miR21 and repression of Grhl3 by leptin mediates sinusoidal endothelial injury in experimental nonalcoholic steatohepatitis.
abstract: Sinusoidal endothelial dysfunction (SED) has been found to be an early event in nonalcoholic steatohepatitis (NASH) progression but the molecular mechanisms underlying its causation remains elusive. We hypothesized that adipokine leptin worsens sinusoidal injury by decreasing functionally active nitric oxide synthase 3 (NOS)3 via miR21. Using rodent models of NASH, and transgenic mice lacking leptin and leptin receptor, results showed that hyperleptinemia caused a 4-5 fold upregulation of hepatic miR21 as assessed by qRTPCR. The upregulation of miR21 led to a time-dependent repression of its target protein Grhl3 levels as shown by western blot analyses. NOS3-p/NOS3 ratio which is controlled by Grhl3 was significantly decreased in NASH models. SED markers ICAM-1, VEGFR-2, and E-selectin as assessed by immunofluorescence microscopy were significantly up regulated in the progressive phases of NASH. Lack of leptin or its receptor in vivo, reversed the upregulation of miR21 and restored the levels of Grhl3 and NOS3-p/NOS3 ratio coupled with decreased SED dysfunction markers. Interestingly, leptin supplementation in mice lacking leptin, significantly enhanced miR21 levels, decreased Grhl3 repression and NOS3 phosphorylation. Leptin supplementation in isolated primary endothelial cells, Kupffer cells and stellate cells showed increased mir21 expression in stellate cells while sinusoidal injury was significantly higher in all cell types. Finally miR21 KO mice showed increased NOS3-p/NOS3 ratio and reversed SED markers in the rodent models of NASH. The experimental results described here show a close association of leptin-induced miR21 in aiding sinusoidal injury in NASH.
authors: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC, 29208, United States of America.
authors: Sahar
authors: S
authors: Pourhoseini
authors: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC, 29208, United States of America.
authors: Ratanesh Kumar
authors: RK
authors: Seth
authors: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC, 29208, United States of America.
authors: Suvarthi
authors: S
authors: Das
authors: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC, 29208, United States of America.
authors: Diptadip
authors: D
authors: Dattaroy
authors: Free Radical Metabolism Group, Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, United States of America.
authors: Maria B
authors: MB
authors: Kadiiska
authors: Division of Gastroenterology, Duke University, Durham, NC, 27707, United States of America.
authors: Guanhua
authors: G
authors: Xie
authors: Division of Gastroenterology, Duke University, Durham, NC, 27707, United States of America.
authors: Gregory A
authors: GA
authors: Michelotti
authors: Dept. of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, 29209, United States of America.
authors: Mitzi
authors: M
authors: Nagarkatti
authors: Division of Gastroenterology, Duke University, Durham, NC, 27707, United States of America.
authors: Anna Mae
authors: AM
authors: Diehl
authors: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC, 29208, United States of America.
authors: Saurabh
authors: S
authors: Chatterjee
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004727:Endothelium / Q000378:metabolism* / Q000503:physiopathology; D005786:Gene Expression Regulation / Q000235:genetics*; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000378:metabolism*; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications* / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D020738:Leptin; D035683:MicroRNAs; D014157:Transcription Factors; C499942:Grhl3 protein, mouse; C531950:MIRN21 microRNA, mouse