1,25-dihydroxyvitamin D3 suppresses renin gene transcription by blocking the activity of the cyclic AMP response element in the renin gene promoter.
Level 5 - mechanism / opinion, no new human data
In vitro bench molecular study without human data (CEBM level 5)
PubMed 17690094 · doi:10.1074/jbc.M705495200
What was done
The authors examined the molecular mechanism by which 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] suppresses mouse Ren-1c gene transcription using promoter luciferase reporter assays with deletion constructs, site-directed mutagenesis of the cAMP response element (CRE), electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP), and GST pull-down assays.
What was found
Deletion analysis identified two promoter fragments (-2,725 to -2,647 and -117 to +6) sufficient to mediate repression. Mutation of the distal CRE blunted both forskolin stimulation and 1,25(OH)2D3-mediated transcriptional inhibition. EMSA showed 1,25(OH)2D3 inhibited nuclear protein binding to the CRE. ChIP and GST pull-down assays demonstrated that liganded vitamin D receptor directly bound CREB via its ligand-binding domain, blocking CREB binding to the CRE. The repression was rescued by CREB, CBP, or p300 overexpression. The abstract reports no numerical values.
Why it matters
This study defines the molecular pathway through which active vitamin D directly down-regulates renin expression by disrupting the CRE-CREB-CBP transcriptional complex.
Limits
The study is restricted to in vitro molecular assays analyzing the mouse renin promoter, with no in vivo animal models or human clinical data reported in the abstract. Quantitative effect sizes, concentrations, and statistical metrics are not provided in the abstract.
Cited by
- supports Vitamin D functions as an endocrine repressor of the renin-angiotensin system by downregulating renin gene expression.