MP74-16 REGULATION OF CPI-17-INDUCED CONTRACTION IN DETRUSOR SMOOTH MUSCLE BY MYOCYTE-SPECIFIC ENHANCER FACTOR (MEF)-2D

Abstract

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Non-neurogenic Voiding Dysfunction I1 Apr 2016MP74-16 REGULATION OF CPI-17-INDUCED CONTRACTION IN DETRUSOR SMOOTH MUSCLE BY MYOCYTE-SPECIFIC ENHANCER FACTOR (MEF)-2D Ettickan Boopathi, Stephan Zderic, and Samuel Chacko Ettickan BoopathiEttickan Boopathi More articles by this author , Stephan ZdericStephan Zderic More articles by this author , and Samuel ChackoSamuel Chacko More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1713AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Protein kinase C (PKC)-potentiated inhibitory protein of 17 kDa (CPI-17) inhibits myosin light chain phosphatase and induces detrusor smooth muscle contraction by maintaining the levels of myosin light chain (MLC) phosphorylation. Dysregulation of CPI-17 expression and phosphorylation has been linked to pathological conditions associated with detrusor smooth muscle contractile dysfunction in bladder outlet obstruction (BOO)-induced bladder smooth muscle (BSM) hypertrophy. Overexpression of CPI-17 is associated with the increased basal MLC phosphorylation and the high degree of force maintenance, and slow relaxation of BSM in BOO. These studies suggest that CPI-17 expression and activation may contribute to bladder overactivity in BPH patients. However, the mechanism by which the transcriptional regulation of CPI-17 in BSM is not known. In the present study, we sought to identify the transcription machinery critical for CPI-17 expression and PKC mediated smooth muscle contraction during BSM hypertrophy in partial bladder outlet obstruction (PBOO) using murine models METHODS We used DNA affinity column chromatography and chromatin immunoprecipitation to identify the binding of transcription factors to the murine CPI-17 promoter in BSM tissues from normal and obstructed bladders of mouse. Bladder sections prepared from sham-operated and PBOO mice were subjected to immunofluorescence and confocal microscopy to localize the specific transcription factor within the muscle bundles. Functional studies were carried out using muscle strips stimulated with PDBu (Phorbol 12,13-dibutyrate). RESULTS Findings from a combination of DNA affinity chromatography, and chromatin immunoprecipitation studies demonstrated that the transcription factor, MEF-2D binds to AT-rich motif of the promoter and regulates CPI-17 gene expression. The DNA binding activity of MEF-2D and expression of CPI-17 was higher in BSM tissues from PBOO mice bladder compared to controls. Overexpression of MEF-2D in murine BSM cells and strips resulted in up-regulation of CPI-17. MEF-2D overexpression in BSM strips significantly increased the forces in response to PDBu compared to vector controls. CONCLUSIONS Our data identify MEF-2D as a critical regulator of CPI-17 expression in BSM and contribute to BSM contractility. This study provides the mechanism mediating CPI-17 overexpression during pathological BSM hypertrophy and implicates MEF-2D as a therapeutic target for the treatment of bladder overactivity in BPH patients. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e975-e976 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Ettickan Boopathi More articles by this author Stephan Zderic More articles by this author Samuel Chacko More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...