Glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 modulate beta-cell chromatin structure.
Chromatin can exert a regulatory effect on gene transcription by modulating the access of transcription factors to target genes. In the present study, we examined whether nuclear actions of the incretin hormones, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1, involve modulation of beta-cell chromatin structure. Stimulation of INS-1(832/13) beta-cells or dispersed mouse islets with glucose-dependent insulinotropic polypeptide or glucagon-like peptide-1 resulted in the post-translational modification of core H3 histones, through acetylation and phosphorylation. Both increased histone H3 acetyltransferase and reduced histone deacetylase activities contributed. Subsequent studies demonstrated that incretin-mediated histone H3 modifications involved activation of protein kinase A, p42/44 mitogen-activated protein kinase (MAPK), and p38 MAPK signaling modules, resulting in the activation of mitogen- and stress-activated kinase-1. Additionally, modification of histone H3 increased its association with the transcription factor, phosphorylated cAMP-response element-binding protein (phospho-CREB) and with cAMP-responsive CREB coactivator 2. Incretin-activated CREB-related Bcl-2 transcription was greatly reduced by a histone acetyltransferase inhibitor, demonstrating the functional importance of histone H3 modification. This appears to be the first demonstration of beta-cell chromatin modification in response to the incretins and the studies indicate that their regulatory effects involve coordinated nuclear interactions between specific signaling modules, chromatin-modifying enzymes and transcription factors.
Kim
Su-Jin
SJ
Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
Nian
Cuilan
C
McIntosh
Christopher H S
CH
D000107:Acetylation; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D005749:Gastric Inhibitory Polypeptide / Q000494:pharmacology*; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism; D047468:Immunoprecipitation; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors
D002843:Chromatin; C504923:Crtc2 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D006657:Histones; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C116919:mitogen and stress-activated protein kinase 1; D020928:Mitogen-Activated Protein Kinases; C484389:Hdac1 protein, mouse; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D005947:Glucose