MP54-12 IMPAIRMENT OF AMPK-α2 BY ISCHEMIA PROVOKES DETRUSOR OVERACTIVITY VIA CELLULAR STRESS SENSORS

Abstract

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Basic Research & Pathophysiology (MP54)1 Apr 2020MP54-12 IMPAIRMENT OF AMPK-α2 BY ISCHEMIA PROVOKES DETRUSOR OVERACTIVITY VIA CELLULAR STRESS SENSORS Jinghua Yang, Yedan Li, Michelle Azad, and Kazem Azadzoi* Jinghua YangJinghua Yang More articles by this author , Yedan LiYedan Li More articles by this author , Michelle AzadMichelle Azad More articles by this author , and Kazem Azadzoi*Kazem Azadzoi* More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000916.012AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Adenosine monophosphate-activated protein kinase alpha 2 (AMPK-α2) is a subunit of AMPK with catalytic kinase domain that senses cellular energy deprivation and signals cellular nutrients deficiency. Our goal was to examine functional consequences of AMPK-α2 responses in bladder ischemia. METHODS: A rat model of bladder ischemia was developed by engendering aorto-iliac arterial atherosclerosis. After 8 weeks, ischemic and sham control bladder tissues were processed for analysis of AMPK-α2 expression and AMPK-α2 translocation and activity using western blotting and ELISA. Ischemia-mediated cellular stress was examined by real-time PCR analysis of the cellular stress sensor upstream stimulatory factor 1 (USF1). USF1-mediated smooth muscle contractile activity was examined in the organ bath. In follow up experiments, rats with bladder ischemia were treated with the AMPK-α2 activator 5-aminoimidazole-4-carboxamide-1-beta-D ribofuranoside (AICAR) or placebo in daily basis for 4 weeks then conscious cystometry was performed and bladder tissues were processed for analysis of AMPK-α2, USF1, and smooth muscle contractile activity, as described earlier. RESULTS: Ischemia upregulated AMPK-α2 expression while blocking AMPK-α2 translocation from cytoplasm to the nucleus. Blockade of AMPK-α2 translocation was associated with significant decrease in AMPK-α2 catalytic activity, suggesting loss of cellular energy deprivation sensing via AMPK-α2 in bladder ischemia. Impairment of AMPK-α2 activity upregulated the expression of cellular stress sensor USF1, implying cellular stress responses via AMPK-α2/USF1 pathway in bladder ischemia. These changes shifted contractile reactivity of ischemic bladder tissues to electrical field stimulation (EFS) to the left and produced cystometric changes consistent with detrusor overactivity. Treatment of bladder tissues with the USF1 inhibitor C527 reversed hyperreactivity to EFS. Treatment of rats with the AMPK-α2 activator AICAR significantly downregulated USF1 expression and diminished cystometric markers of detrusor overactivity in bladder ischemia. CONCLUSIONS: Impairment of AMPK-α2 by ischemia upregulated USF1 and provoked detrusor overactivity by activation of cellular stress responses. The mechanism appeared to involve USF1-directed smooth muscle hyperreactivity via cellular stress signaling pathway. Our data suggest that activators of AMPK-α2 and inhibitors of USF1 may have valuable therapeutic potentials against overactive bladder. Source of Funding: Supported by Merit Review Award Number I01 BX004372 from the United States (U.S.) Department of Veterans Affairs Biomedical Laboratory R&D (BLRD) Service. © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e795-e796 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jinghua Yang More articles by this author Yedan Li More articles by this author Michelle Azad More articles by this author Kazem Azadzoi* More articles by this author Expand All Advertisement PDF downloadLoading ...