title: Novel mechanism of transcriptional regulation of cell matrix protein through CREB.
abstract: The transcription mechanism(s) of renal cell matrix accumulation in diabetes does not explored. Phosphorylation of the transcription factor cAMP-responsive element binding protein (CREB) significantly increased in cells treated with high glucose (HG) compared to cell grown in normal glucose (NG). Cells pretreated with rapamycin before exposure to HG showed significant decrease phosphorylation of CREB, increase in AMPK activity and decrease protein/mRNA and promoter activity of fibronectin. In addition, cells transfected with siRNA against CREB showed significant increase in AMPK activity, decrease in protein/mRNA and promoter activity of fibronectin. Cells treated with HG showed nuclear localization of p-CREB while pretreated cells with rapamycin reversed HG effect. Moreover, gel shift analysis shows increase binding of CREB to fibronectin promoter in cells treated with HG while cells pretreated with rapamycin reversed the effect of HG. Furthermore, db/db mice treated with rapamycin showed significant increase in AMPK activity, decrease in expression of p-CREB and protein/mRNA of fibronectin. Strong staining of fibronectin and p-CREB was detected in kidney cortex of db/db mice while treated mice with rapamycin reversed hyperglycemia effect. In summary, our data provide a novel mechanism of transcriptional regulation of fibronectin through CREB that may be used as therapeutic approach to prevent diabetes complications.
authors.affiliation: a South Texas Veterans Health Care System ; San Antonio , TX USA.
authors.forename: Samy L
authors.initials: SL
authors.lastname: Habib
authors.forename: Sumathy
authors.initials: S
authors.lastname: Mohan
authors.forename: Sitai
authors.initials: S
authors.lastname: Liang
authors.forename: Baojie
authors.initials: B
authors.lastname: Li
authors.forename: Mukesh
authors.initials: M
authors.lastname: Yadav
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology*; D003920:Diabetes Mellitus / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D008820:Mice, Obese; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D014158:Transcription, Genetic
chemical_list: C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D005353:Fibronectins; D000263:Adenylate Kinase
keywords: AMPK; CREB; cell matrix; fibronectin; renal cells; transcription