title: Pro-inflammatory role of microrna-200 in vascular smooth muscle cells from diabetic mice.
abstract: OBJECTIVE
  Vascular smooth muscle cells (VSMC) from type 2 diabetic db/db mice exhibit enhanced proinflammatory responses implicated in accelerated vascular complications. We examined the role of microRNA(miR)-200 family members and their target Zeb1, an E-box binding transcriptional repressor, in these events.
  
  
  RESULTS
  The expression levels of miR-200b, miR-200c, and miR-429 were increased, although protein levels of Zeb1 were decreased in VSMC and aortas from db/db mice relative to control db/+ mice. Transfection of miR-200 mimics into VSMC downregulated Zeb1 by targeting its 3'-UTR, upregulated the inflammatory genes cyclooxygenase-2 and monocyte chemoattractant protein-1, and promoted monocyte binding in db/+VSMC. In contrast, miR-200 inhibitors reversed the enhanced monocyte binding of db/dbVSMC. Zeb1 gene silencing with siRNAs also increased these proinflammatory responses in db/+VSMC confirming negative regulatory role of Zeb1. Both miR-200 mimics and Zeb1 siRNAs increased cyclooxygenase-2 promoter transcriptional activity. Chromatin immunoprecipitation showed that Zeb1 occupancy at inflammatory gene promoters was reduced in VSMC from type 2 diabetic db/db mice. Furthermore, Zeb1 knockdown increased miR-200 levels demonstrating a feedback regulatory loop.
  
  
  CONCLUSIONS
  Disruption of the reciprocal negative regulatory loop between miR-200 and Zeb1 under diabetic conditions enhances proinflammatory responses of VSMC implicated in vascular complications.
authors.affiliation: Department of Diabetes, Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
authors.forename: Marpadga A
authors.initials: MA
authors.lastname: Reddy
authors.forename: Wen
authors.initials: W
authors.lastname: Jin
authors.forename: Louisa
authors.initials: L
authors.lastname: Villeneuve
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Linda
authors.initials: L
authors.lastname: Lanting
authors.forename: Ivan
authors.initials: I
authors.lastname: Todorov
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kato
authors.forename: Rama
authors.initials: R
authors.lastname: Natarajan
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001013:Aorta, Thoracic / Q000276:immunology / Q000378:metabolism; D001665:Binding Sites; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D003925:Diabetic Angiopathies / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation; D025461:Feedback, Physiological; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism*; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000276:immunology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000276:immunology / Q000378:metabolism*; D034622:RNA Interference; D014162:Transfection; D015854:Up-Regulation; D000071799:Zinc Finger E-box-Binding Homeobox 1
chemical_list: D020413:3' Untranslated Regions; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D018398:Homeodomain Proteins; D018836:Inflammation Mediators; D051741:Kruppel-Like Transcription Factors; D035683:MicroRNAs; C543719:Mirn200 microRNA, mouse; C519422:ZEB1 protein, mouse; D000071799:Zinc Finger E-box-Binding Homeobox 1; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2