Inhibition of O-GlcNAcase using a potent and cell-permeable inhibitor does not induce insulin resistance in 3T3-L1 adipocytes.
To probe increased O-GlcNAc levels as an independent mechanism governing insulin resistance in 3T3-L1 adipocytes, a new class of O-GlcNAcase (OGA) inhibitor was studied. 6-Acetamido-6-deoxy-castanospermine (6-Ac-Cas) is a potent inhibitor of OGA. The structure of 6-Ac-Cas bound in the active site of an OGA homolog reveals structural features contributing to its potency. Treatment of 3T3-L1 adipocytes with 6-Ac-Cas increases O-GlcNAc levels in a dose-dependent manner. These increases in O-GlcNAc levels do not induce insulin resistance functionally, measured using a 2-deoxyglucose (2-DOG) uptake assay, or at the molecular level, determined by evaluating levels of phosphorylated IRS-1 and Akt. These results, and others described, provide a structural blueprint for improved inhibitors and collectively suggest that increased O-GlcNAc levels, brought about by inhibition of OGA, does not by itself cause insulin resistance in 3T3-L1 adipocytes.
Macauley
Matthew S
MS
Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada.
He
Yuan
Y
Gloster
Tracey M
TM
Stubbs
Keith A
KA
Davies
Gideon J
GJ
Vocadlo
David J
DJ
D041721:3T3-L1 Cells; D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000494:pharmacology; D017667:Adipocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003847:Deoxyglucose / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D007212:Indolizines / Q000737:chemistry* / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance; D051379:Mice; D010091:Oximes / Q000494:pharmacology; D048448:Phenylcarbamates / Q000494:pharmacology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D001619:beta-N-Acetylhexosaminidases / Q000037:antagonists & inhibitors* / Q000378:metabolism
C555049:6-acetamido-6-deoxycastanospermine; D004791:Enzyme Inhibitors; D007212:Indolizines; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010091:Oximes; D048448:Phenylcarbamates; C068836:N-acetylglucosaminono-1,5-lactone O-(phenylcarbamoyl)oxime; D003847:Deoxyglucose; D051057:Proto-Oncogene Proteins c-akt; C110628:hexosaminidase C; D001619:beta-N-Acetylhexosaminidases; D000117:Acetylglucosamine