title: Acute overactive endocannabinoid signaling induces glucose intolerance, hepatic steatosis, and novel cannabinoid receptor 1 responsive genes.
abstract: Endocannabinoids regulate energy balance and lipid metabolism by stimulating the cannabinoid receptor type 1 (CB1). Genetic deletion and pharmacological antagonism have shown that CB1 signaling is necessary for the development of obesity and related metabolic disturbances. However, the sufficiency of endogenously produced endocannabinoids to cause hepatic lipid accumulation and insulin resistance, independent of food intake, has not been demonstrated. Here, we show that a single administration of isopropyl dodecylfluorophosphonate (IDFP), perhaps the most potent pharmacological inhibitor of endocannabinoid degradation, increases hepatic triglycerides (TG) and induces insulin resistance in mice. These effects involve increased CB1 signaling, as they are mitigated by pre-administration of a CB1 antagonist (AM251) and in CB1 knockout mice. Despite the strong physiological effects of CB1 on hepatic lipid and glucose metabolism, little is known about the downstream targets responsible for these effects. To elucidate transcriptional targets of CB1 signaling, we performed microarrays on hepatic RNA isolated from DMSO (control), IDFP and AM251/IDFP-treated mice. The gene for the secreted glycoprotein lipocalin 2 (lcn2), which has been implicated in obesity and insulin resistance, was among those most responsive to alterations in CB1 signaling. The expression pattern of IDFP mice segregated from DMSO mice in hierarchal cluster analysis and AM251 pre-administration reduced (>50%) the majority (303 of 533) of the IDFP induced alterations. Pathway analysis revealed that IDFP altered expression of genes involved in lipid, fatty acid and steroid metabolism, the acute phase response, and amino acid metabolism in a CB1-dependent manner. PCR confirmed array results of key target genes in multiple independent experiments. Overall, we show that acute IDFP treatment induces hepatic TG accumulation and insulin resistance, at least in part through the CB1 receptor, and identify novel cannabinoid responsive genes.
authors.affiliation: Department of Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, California, United States of America.
authors.forename: Maxwell A
authors.initials: MA
authors.lastname: Ruby
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Nomura
authors.forename: Carolyn S S
authors.initials: CS
authors.lastname: Hudak
authors.forename: Anne
authors.initials: A
authors.lastname: Barber
authors.forename: John E
authors.initials: JE
authors.lastname: Casida
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Krauss
mesh_terms: D000818:Animals; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism*; D063388:Endocannabinoids; D005234:Fatty Liver / Q000378:metabolism*; D005951:Glucose Tolerance Test; D007333:Insulin Resistance; D051379:Mice; D016133:Polymerase Chain Reaction; D043884:Receptor, Cannabinoid, CB1 / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D043884:Receptor, Cannabinoid, CB1
references.citation: J Lipid Res. 2011 Feb;52(2):337-44
references.pmid: 21097653
references.citation: Life Sci. 1998;63(8):PL113-7
references.pmid: 9718088
references.citation: Biochim Biophys Acta. 2000 Oct 18;1482(1-2):9-24
references.pmid: 11058743
references.citation: Liver Int. 2010 Nov;30(10):1482-9
references.pmid: 20602678
references.citation: Diabetes. 2010 Jun;59(6):1376-85
references.pmid: 20332347
references.citation: Eur Heart J. 2008 Jul;29(14):1761-71
references.pmid: 18417461
references.citation: Bull Environ Contam Toxicol. 2001 Oct;67(4):463-9
references.pmid: 11779058
references.citation: Clin Pharmacol Ther. 1974 Aug;16(2):297-302
references.pmid: 4851289
references.citation: Proc Natl Acad Sci U S A. 1999 May 11;96(10):5780-5
references.pmid: 10318961
references.citation: Mol Cell Endocrinol. 2008 Apr 16;286(1-2 Suppl 1):S66-78
references.pmid: 18343566
references.citation: Pain. 1998 Mar;75(1):111-119
references.pmid: 9539680
references.citation: J Clin Invest. 2005 May;115(5):1298-305
references.pmid: 15864349
references.citation: J Assoc Physicians India. 2000 Dec;48(12):1197-9
references.pmid: 11280228
references.citation: J Clin Invest. 2010 Aug;120(8):2953-66
references.pmid: 20664173
references.citation: Proc Natl Acad Sci U S A. 2004 Jul 13;101(28):10422-7
references.pmid: 15240880
references.citation: Can Med Assoc J. 1981 Mar 15;124(6):745-8
references.pmid: 7471018
references.citation: J Biol Chem. 2011 May 20;286(20):17467-77
references.pmid: 21454566
references.citation: Proc Natl Acad Sci U S A. 2008 Sep 23;105(38):14561-6
references.pmid: 18794527
references.citation: J Clin Invest. 2008 Sep;118(9):3160-9
references.pmid: 18677409
references.citation: J Clin Invest. 2004 Apr;113(8):1202-9
references.pmid: 15085199
references.citation: Int J Obes (Lond). 2010 Mar;34(3):557-68
references.pmid: 20029375
references.citation: Int J Obes Relat Metab Disord. 2004 Apr;28(4):640-8
references.pmid: 14770190
references.citation: Lancet. 2006 Nov 11;368(9548):1660-72
references.pmid: 17098084
references.citation: Diabetologia. 2009 Feb;52(2):213-7
references.pmid: 18972095
references.citation: Toxicol Sci. 2003 Nov;76(1):131-7
references.pmid: 12944586
references.citation: Nat Med. 2008 Jun;14(6):667-75
references.pmid: 18516053
references.citation: Int J Obes (Lond). 2005 Jul;29(7):755-9
references.pmid: 15809662
references.citation: Nat Med. 2004 Feb;10(2):168-74
references.pmid: 14716305
references.citation: Br J Pharmacol. 2009 Sep;158(2):451-61
references.pmid: 19371345
references.citation: Mol Cell Biol. 2001 Mar;21(5):1621-32
references.pmid: 11238899
references.citation: Cell. 2005 Jan 28;120(2):261-73
references.pmid: 15680331
references.citation: Nat Rev Neurosci. 2003 Nov;4(11):873-84
references.pmid: 14595399
references.citation: Gut. 2009 Aug;58(8):1135-43
references.pmid: 19282305
references.citation: J Biol Chem. 2005 Sep 30;280(39):33426-34
references.pmid: 16046413
references.citation: J Biol Chem. 2009 Oct 9;284(41):27816-27826
references.pmid: 19648649
references.citation: Diabetes. 2006 Nov;55(11):3053-60
references.pmid: 17065342
references.citation: Br J Pharmacol. 2003 Sep;140(1):115-22
references.pmid: 12967941
references.citation: J Toxicol Clin Toxicol. 1983 Jun;20(4):381-5
references.pmid: 6655779
references.citation: JAMA. 2002 Dec 4;288(21):2709-16
references.pmid: 12460094
references.citation: Nat Neurosci. 2009 Sep;12(9):1152-8
references.pmid: 19648913
references.citation: J Pharmacol Exp Ther. 1994 Jul;270(1):219-27
references.pmid: 8035318
references.citation: N Engl J Med. 2005 Nov 17;353(20):2121-34
references.pmid: 16291982
references.citation: J Clin Invest. 2003 Aug;112(3):423-31
references.pmid: 12897210
references.citation: J Clin Invest. 2009 May;119(5):1359-72
references.pmid: 19425170
references.citation: JAMA. 2006 Feb 15;295(7):761-75
references.pmid: 16478899
references.citation: Int J Obes (Lond). 2005 Feb;29(2):183-7
references.pmid: 15558076
references.citation: Gastroenterology. 2008 Apr;134(4):1148-58
references.pmid: 18395093
references.citation: Chem Biol. 2009 Jul 31;16(7):744-53
references.pmid: 19635411
references.citation: Toxicol Lett. 2008 Nov 10;182(1-3):42-7
references.pmid: 18789379
references.citation: Am J Physiol Regul Integr Comp Physiol. 2003 Feb;284(2):R345-53
references.pmid: 12399252
references.citation: Nat Neurosci. 2010 Sep;13(9):1113-9
references.pmid: 20729846
references.citation: Nature. 2001 Apr 12;410(6830):822-5
references.pmid: 11298451
references.citation: FASEB J. 2005 Sep;19(11):1567-9
references.pmid: 16009704
references.citation: Cell Metab. 2008 Mar;7(3):227-35
references.pmid: 18316028
references.citation: Chem Rev. 2008 May;108(5):1687-707
references.pmid: 18429637
references.citation: J Biol Chem. 1995 Sep 22;270(38):22565-70
references.pmid: 7545679
references.citation: J Biol Chem. 2006 Dec 1;281(48):37246-55
references.pmid: 17028193
references.citation: Nat Chem Biol. 2008 Jun;4(6):373-8
references.pmid: 18438404
references.citation: Diabetes. 2005 Oct;54(10):2838-43
references.pmid: 16186383
references.citation: Proc Natl Acad Sci U S A. 2009 Dec 1;106(48):20270-5
references.pmid: 19918051
references.citation: Lancet. 2005 Apr 16-22;365(9468):1389-97
references.pmid: 15836887
references.citation: Diabetes. 2010 Apr;59(4):872-82
references.pmid: 20068130