Jornayvaz, F.R.* ; Birkenfeld, A.L.* ; Jurczak, M.J.* ; Kanda, S.* ; Guigni, B.A.* ; Jiang, D.* ; Zhang, D.* ; Lee, H.Y.* ; Samuel, V.T.* ; Shulman, G.I.*
    
    
        
Hepatic insulin resistance in mice with hepatic overexpression of diacylglycerol acyltransferase 2.
    
    
        
    
    
        
        Proc. Natl. Acad. Sci. U.S.A. 108, 5748-5752 (2011)
    
    
 	
    
	
	  DOI
 DOI
	  PMC
 PMC
		
		
			Open Access Gold as soon as Publ. Version/Full Text is submitted to ZB.
		
     
    
      
      
	
	    Mice overexpressing acylCoA:diacylglycerol (DAG) acyltransferase 2 in the liver (Liv-DGAT2) have been shown to have normal hepatic insulin responsiveness despite severe hepatic steatosis and increased hepatic triglyceride, diacylglycerol, and ceramide content, demonstrating a dissociation between hepatic steatosis and hepatic insulin resistance. This led us to reevaluate the role of DAG in causing hepatic insulin resistance in this mouse model of severe hepatic steatosis. Using hyperinsulinemic-euglycemic clamps, we studied insulin action in Liv-DGAT2 mice and their wild-type (WT) littermate controls. Here, we show that Liv-DGAT2 mice manifest severe hepatic insulin resistance as reflected by decreased suppression of endogenous glucose production (0.8 ± 41.8 vs. 87.7 ± 34.3% in WT mice, P < 0.01) during the clamps. Hepatic insulin resistance could be attributed to an almost 12-fold increase in hepatic DAG content (P < 0.01) resulting in a 3.6-fold increase in protein kinase Cε (PKCε) activation (P < 0.01) and a subsequent 52% decrease in insulin-stimulated insulin receptor substrate 2 (IRS-2) tyrosine phosphorylation (P < 0.05), as well as a 64% decrease in fold increase pAkt/Akt ratio from basal conditions (P < 0.01). In contrast, hepatic insulin resistance in these mice was not associated with increased endoplasmic reticulum (ER) stress or inflammation. Importantly, hepatic insulin resistance in Liv-DGAT2 mice was independent of differences in body composition, energy expenditure, or food intake. In conclusion, these findings strengthen the link between hepatic steatosis and hepatic insulin resistance and support the hypothesis that DAG-induced PKCε activation plays a major role in nonalcoholic fatty liver disease (NAFLD)-associated hepatic insulin resistance.
	
	
	    
	
       
      
	
	    
		Impact Factor
		Scopus SNIP
		Web of Science
Times Cited
		Scopus
Cited By
		Altmetric
		
	     
	    
	 
       
      
     
    
        Publication type
        Article: Journal article
    
 
    
        Document type
        Scientific Article
    
 
    
        Thesis type
        
    
 
    
        Editors
        
    
    
        Keywords
        
    
 
    
        Keywords plus
        
    
 
    
    
        Language
        english
    
 
    
        Publication Year
        2011
    
 
    
        Prepublished in Year
        
    
 
    
        HGF-reported in Year
        0
    
 
    
    
        ISSN (print) / ISBN
        0027-8424
    
 
    
        e-ISSN
        1091-6490
    
 
    
        ISBN
        
    
    
        Book Volume Title
        
    
 
    
        Conference Title
        
    
 
	
        Conference Date
        
    
     
	
        Conference Location
        
    
 
	
        Proceedings Title
        
    
 
     
	
    
        Quellenangaben
        
	    Volume: 108,  
	    Issue: 14,  
	    Pages: 5748-5752 
	    Article Number: ,  
	    Supplement: ,  
	
    
 
    
        
            Series
            
        
 
        
            Publisher
            National Academy of Sciences
        
 
        
            Publishing Place
            
        
 
	
        
            Day of Oral Examination
            0000-00-00
        
 
        
            Advisor
            
        
 
        
            Referee
            
        
 
        
            Examiner
            
        
 
        
            Topic
            
        
 
	
        
            University
            
        
 
        
            University place
            
        
 
        
            Faculty
            
        
 
    
        
            Publication date
            0000-00-00
        
 
         
        
            Application date
            0000-00-00
        
 
        
            Patent owner
            
        
 
        
            Further owners
            
        
 
        
            Application country
            
        
 
        
            Patent priority
            
        
 
    
        Reviewing status
        Peer reviewed
    
 
    
        Institute(s)
        Institute of Pancreatic Islet Research (IPI)
    
 
    
        POF-Topic(s)
        
    
 
    
        Research field(s)
        
    
 
    
        PSP Element(s)
        
    
 
    
        Grants
        
    
 
    
        Copyright
        
    
 	
    
    
    
        Erfassungsdatum
        2011-12-31