Document Detail


Smooth muscle myosin expression, isoform composition, and functional activities in rat corpus cavernosum altered by the streptozotocin-induced type 1 diabetes.
MedLine Citation:
PMID:  21917637     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Diabetes mellitus (DM) is a quite common chronic disease, and the prevalence of erectile dysfunction (ED) is three times higher in this large population. Although diabetes-related ED has been studied extensively, the actin-myosin contractile apparatus was not examined. The mRNAs encoding smooth muscle myosin (SMM) heavy chains (MHC) and essential light chains (LC(17)) exist as several different alternatively spliced isoforms with distinct contractile properties. Recently, we provided novel data that blebbistatin (BLEB), a specific myosin II inhibitor, potently relaxed corpus cavernosum smooth muscle (CCSM). In this study, we examine whether diabetes alters SMM expression, alternative splicing, and/or functional activities, including sensitivity to BLEB. By using streptozotocin (STZ)-induced 2-mo diabetic rats, functional activities were tested in vivo by intracavernous pressure (ICP) recording during cavernous nerve stimulation and in vitro via organ bath contractility studies. SMM isoform composition was analyzed by competitive RT-PCR and total SMM, myocardin, and embryonic SMM (SMemb) expression by real-time RT-PCR. Results revealed that the blood glucose level of STZ rats was 407.0 vs. 129.5 mg/dl (control). STZ rats exhibited ED confirmed by significantly increased CCSM contractile response to phenylephrine and decreased ICP response. For STZ rats, SM-B, LC(17a) and SM2 isoforms, total SMM, and myocardin expression increased, whereas SM-A, LC(17b), and SM1 isoforms were decreased, with SMemb unchanged. BLEB was significantly more effective in relaxing STZ CCSM both in vitro and in vivo. Thus we demonstrated a novel diabetes-specific effect on alternative splicing of the SMM heavy chain and essential light chain genes to a SMM isoform composition favoring a heightened contractility and ED. A switch to a more contractile phenotype was supported further by total SMM expression increase. Moreover, the change in CCSM phenotype was associated with an increased sensitivity to BLEB, which may serve as a novel pharmacotherapy for ED.
Authors:
Xinhua Zhang; Nirmala D Kanika; Arnold Melman; Michael E DiSanto
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, N.I.H., Extramural     Date:  2011-09-13
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  302     ISSN:  1522-1555     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2011-12-19     Completed Date:  2012-02-14     Revised Date:  2012-04-20    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E32-42     Citation Subset:  IM    
Affiliation:
Department of Urology, Albert Einstein College of Medicine, Bronx, NY, USA.
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MeSH Terms
Descriptor/Qualifier:
Alternative Splicing
Animals
Diabetes Mellitus, Type 1 / complications,  metabolism*,  physiopathology*
Drug Resistance
Enzyme Inhibitors / pharmacology
Erectile Dysfunction / complications,  drug therapy,  metabolism*,  physiopathology*
Gene Expression Regulation
Heterocyclic Compounds with 4 or More Rings / pharmacology
Male
Muscle Contraction / drug effects
Muscle, Smooth / drug effects,  metabolism,  physiopathology
Myosin Heavy Chains / genetics,  metabolism
Myosin Light Chains / genetics,  metabolism
Myosin Type II / antagonists & inhibitors
Nuclear Proteins / genetics,  metabolism
Penis / drug effects,  innervation,  metabolism*,  physiopathology*
Protein Isoforms / genetics,  metabolism
RNA, Messenger / metabolism
Rats
Rats, Inbred F344
Smooth Muscle Myosins / genetics,  metabolism*
Streptozocin / toxicity
Trans-Activators / genetics,  metabolism
Grant Support
ID/Acronym/Agency:
5-R01-DK-077116/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 0/Heterocyclic Compounds with 4 or More Rings; 0/Myosin Heavy Chains; 0/Myosin Light Chains; 0/Nuclear Proteins; 0/Protein Isoforms; 0/RNA, Messenger; 0/Trans-Activators; 0/blebbistatin; 0/myocardin; 18883-66-4/Streptozocin; EC 3.6.1.-/Myosin Type II; EC 3.6.1.-/Smooth Muscle Myosins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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