title: Purinergic receptor X7 mediates leptin induced GLUT4 function in stellate cells in nonalcoholic steatohepatitis.
abstract: Metabolic oxidative stress via CYP2E1 can act as a second hit in NASH progression. Our previous studies have shown that oxidative stress in NASH causes higher leptin levels and induces purinergic receptor X7 (P2X7r). We tested the hypothesis that higher circulating leptin due to CYP2E1-mediated oxidative stress induces P2X7r. P2X7r in turn activates stellate cells and causes increased proliferation via modulating Glut4, the glucose transporter, and increased intracellular glucose. Using a high fat diet-fed NAFLD model where bromodichloromethane (BDCM) was administered to induce CYP2E1-mediated oxidative stress, we show that P2X7r expression and protein levels were leptin and CYP2E1 dependent. P2X7r KO mice had significantly decreased stellate cell proliferation. Human NASH livers showed marked increase in P2X7r, and Glut4 in α-SMA positive cells. NASH livers had significant increase in Glut4 protein and phosphorylated AKT, needed for Glut4 translocation while leptin KO and P2X7r KO mice showed marked decrease in Glut4 levels primarily in stellate cells. Mechanistically stellate cells showed increase in phosphorylated AKT, Glut4 protein and localization in the membrane following administration of P2X7r agonist or leptin+P2X7r agonist, while use of P2X7r antagonist or AKT inhibitor attenuated the response suggesting that leptin-P2X7r axis in concert but not leptin alone is responsible for the Glut4 induction and translocation. Finally P2X7r-agonist and leptin caused an increase in intracellular glucose and consumption by increasing the activity of hexokinase. In conclusion, the study shows a novel role of leptin-induced P2X7r in modulating Glut4 induction and translocation in hepatic stellate cells, that are key to NASH progression.
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Varun
authors.initials: V
authors.lastname: Chandrashekaran
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Suvarthi
authors.initials: S
authors.lastname: Das
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Ratanesh Kumar
authors.initials: RK
authors.lastname: Seth
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Diptadip
authors.initials: D
authors.lastname: Dattaroy
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Firas
authors.initials: F
authors.lastname: Alhasson
authors.affiliation: Division of Gastroenterology, Duke University, Durham, NC 27707, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Michelotti
authors.affiliation: Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
authors.forename: Mitzi
authors.initials: M
authors.lastname: Nagarkatti
authors.affiliation: Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
authors.forename: Prakash
authors.initials: P
authors.lastname: Nagarkatti
authors.affiliation: Division of Gastroenterology, Duke University, Durham, NC 27707, USA.
authors.forename: Anna Mae
authors.initials: AM
authors.lastname: Diehl
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA. Electronic address: schatt@mailbox.sc.edu.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Chatterjee
mesh_terms: D000818:Animals; D002460:Cell Line; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D055166:Hepatic Stellate Cells / Q000378:metabolism* / Q000473:pathology; D020738:Leptin / Q000378:metabolism*; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008297:Male; D008810:Mice, Inbred C57BL; D065626:Non-alcoholic Fatty Liver Disease / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism*
chemical_list: D051275:Glucose Transporter Type 4; D020738:Leptin; D058486:Receptors, Purinergic P2X7; D019392:Cytochrome P-450 CYP2E1
keywords: CYP2E1; Diallyl sulfide; Glucose transporter; Hexokinase; PI3K