CONTRACTILE PROTEIN EXPRESSION IN BLADDER SMOOTH MUSCLE IS A MARKER OF PHENOTYPIC MODULATION AFTER OUTLET OBSTRUCTION IN THE RABBIT MODEL

Objective: The objective of this study is to determine the role of SPA (surfactant protein A) in vascular smooth muscle cell (SMC) phenotypic modulation and vascular remodeling. Approach and Results: PDGF-BB (Platelet-derived growth factor-BB) and serum induced SPA expression while downregulating SMC marker gene expression in SMCs. SPA deficiency increased the contractile protein expression. Mechanistically, SPA deficiency enhanced the expression of myocardin and TGF (transforming growth factor)-β, the key regulators for contractile SMC phenotype. In vivo, SPA was induced in medial and neointimal SMCs following mechanical injury in both rat and mouse carotid arteries. SPA knockout in mice dramatically attenuated the wire injury-induced intimal hyperplasia while restoring SMC contractile protein expression in medial SMCs. These data indicate that SPA plays an important role in SMC phenotype modulation and vascular remodeling in vivo. Conclusions: SPA is a novel protein factor modulating SMC phenotype. Blocking the abnormal elevation of SPA may be a potential strategy to inhibit the development of proliferative vascular diseases.

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Contractile Protein Changes in Urinary Bladder Smooth Muscle Following Outlet Obstruction

Advances in Experimental Medicine and Biology - Advances in Bladder Research ◽

10.1007/978-1-4615-4737-2_11 ◽

1999 ◽

pp. 137-153 ◽

Cited By ~ 19

Author(s):

Samuel Chacko ◽

Michael DiSanto ◽

Chandrakala Menon ◽

Yongmu Zheng ◽

Joseph Hypolite ◽

...

Keyword(s):

Smooth Muscle ◽

Urinary Bladder ◽

Outlet Obstruction ◽

Contractile Protein ◽

Bladder Smooth Muscle ◽

Urinary Bladder Smooth Muscle

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Deletion of SM-B, the high ATPase isoform of myosin, upregulates the PKC-mediated signal transduction pathway in murine urinary bladder smooth muscle

AJP Renal Physiology ◽

10.1152/ajprenal.90221.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. F658-F665 ◽

Cited By ~ 8

Author(s):

Joseph A. Hypolite ◽

Shaohua Chang ◽

Edward LaBelle ◽

Gopal J. Babu ◽

Muthu Periasamy ◽

...

Keyword(s):

Signal Transduction ◽

Smooth Muscle ◽

Rabbit Model ◽

Outlet Obstruction ◽

Signal Transduction Pathway ◽

Transduction Pathway ◽

Bladder Smooth Muscle ◽

Two Dimensional Gel Electrophoresis ◽

Compensatory Response ◽

Myosin Heavy Chain Isoform

Detrusor smooth muscle (DSM) hypertrophy induced by partial bladder outlet obstruction (PBOO) is associated with changes in the NH2-terminal myosin heavy chain isoform from predominantly SM-B to SM-A, alteration in the Ca2+ sensitization pathway, and the contractile characteristics from phasic to tonic in rabbits. We utilized the SM-B knockout (KO) mouse to determine whether a shift from SM-B to SM-A without PBOO is associated with changes in the signal transduction pathway mediated via PKC and CPI-17, which keeps the myosin phosphorylation (MLC20) level high by inhibiting the myosin phosphatase. DSM strips from SM-B KO mice generated more force in response to electrical field stimulation, KCl, carbachol, and phorbol 12,13-dibutyrate than that of age-matched wild-type mice. There was no difference in the ED50 for carbachol but the maximum response was greater for the SM-B KO mice. DSM from SM-B KO mice revealed increased mass and hypertrophy. The KO mice also showed an overexpression of PKC-α, increased levels of phospho-CPI-17, and an elevated level of IP3 and DAG upon stimulation with carbachol. Two-dimensional gel electrophoresis revealed an increased level of MLC20 phosphorylation in response to carbachol. Together, these changes may be responsible for the higher level of force generation and maintenance by the DSM from the SM-B KO bladders. In conclusion, our data show that ablation of SM-B is associated with alteration of PKC-mediated signal transduction and CPI-17-mediated Ca2+ sensitization pathway that regulate smooth muscle contraction. Interestingly, similar changes are also present in PBOO-induced DSM compensatory response in the rabbit model in which SM-B is downregulated.

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Obstruction-induced changes in urinary bladder smooth muscle contractility: a role for Rho kinase

AJP Renal Physiology ◽

10.1152/ajprenal.00378.2002 ◽

2003 ◽

Vol 285 (5) ◽

pp. F990-F997 ◽

Cited By ~ 114

Author(s):

Wu Bing ◽

Shaohua Chang ◽

Joseph A. Hypolite ◽

Michael E. DiSanto ◽

Stephen A. Zderic ◽

...

Keyword(s):

Smooth Muscle ◽

Rabbit Model ◽

Rho Kinase ◽

Outlet Obstruction ◽

Slow Relaxation ◽

Bladder Smooth Muscle ◽

Smooth Muscle Contractility ◽

Slow Development ◽

Urinary Bladder Smooth Muscle ◽

Force Maintenance

Detrusor smooth muscle (DSM) undergoes hypertrophy after partial bladder outlet obstruction (PBOO) in male rabbits, as it does in men with PBOO induced by benign prostatic hyperplasia. Despite detrusor hypertrophy, some bladders are severely dysfunctional (decompensated). In this study, the rabbit model for PBOO was used to determine the biochemical regulation of the contractile apparatus and force maintenance by the detrusor from decompensated bladders (DB). Bladders from sham-operated rabbits served as a control. On stimulation with 125 mM KCl, the DSM from sham-operated (SB) rabbits showed phasic contractions, whereas the detrusor from DB was tonic, exhibiting slow development of force, a longer duration of force maintenance, and slow relaxation. The Rho kinase (ROK) inhibitor Y-27632 enhanced the relaxation of precontracted DSM strips from DB. The enhancement of relaxation of the KCl-induced contraction of DB by Y-27632 was associated with dephosphorylation of myosin light chain (MLC20). The DSM extract from DB showed low phosphatase activity compared with that from SB. The DB also showed more Ca2+-independent MLC20 phosphorylation, which was partially inhibited by Y-27632. RT-PCR and Western blotting revealed similar expression levels of MLC kinase and ROK-α in SB and DB, but ROK-β was overexpressed in DB. These results suggest that the ROK-mediated pathway is partly responsible for the high degree of force maintenance and slow relaxation in the detrusor from DB.

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1435: Effect of Strip Length on the Contractile Dysfunction of Bladder Smooth Muscle Following Partial Outlet Obstruction

The Journal of Urology ◽

10.1016/s0022-5347(18)35569-1 ◽

2005 ◽

Vol 173 (4S) ◽

pp. 389-389

Author(s):

Robert M. Levin ◽

Timothy Reed ◽

Catherine Whitbeck ◽

Paul Chichester

Keyword(s):

Smooth Muscle ◽

Outlet Obstruction ◽

Contractile Dysfunction ◽

Bladder Smooth Muscle ◽

Strip Length

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Mechanisms of bladder smooth-muscle hypertrophy and decompensation: lessons from normal development and the response to outlet obstruction

World Journal of Urology ◽

10.1007/s003450050079 ◽

1998 ◽

Vol 16 (5) ◽

pp. 350-358 ◽

Cited By ~ 24

Author(s):

Stephen A. Zderic ◽

Alan Wein ◽

Dorothea Rohrman ◽

ChiaoLiang Gong ◽

Denise Nigro ◽

...

Keyword(s):

Smooth Muscle ◽

Muscle Hypertrophy ◽

Normal Development ◽

Outlet Obstruction ◽

Bladder Smooth Muscle

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Endothelial cell-conditioned medium downregulates smooth muscle contractile protein expression

AJP Cell Physiology ◽

10.1152/ajpcell.1997.272.2.c582 ◽

1997 ◽

Vol 272 (2) ◽

pp. C582-C591 ◽

Cited By ~ 14

Author(s):

S. M. Vernon ◽

M. J. Campos ◽

T. Haystead ◽

M. M. Thompson ◽

P. E. DiCorleto ◽

...

Keyword(s):

Smooth Muscle ◽

Endothelial Cell ◽

Growth Factor ◽

Protein Expression ◽

Conditioned Medium ◽

Transforming Growth Factor Beta ◽

Transforming Growth Factor ◽

Contractile Protein ◽

Alpha Actin ◽

Cell Conditioned Medium

Smooth muscle cells (SMC) within atherosclerotic lesions proliferate and exhibit phenotypic modulation, but the contribution of vascular endothelium to this process is poorly understood. Our aim was to examine the effects of endothelial cell-conditioned medium (ECCM) on vascular SMC growth and differentiation. Rat aortic ECCM stimulated a ninefold increase in [3H]thymidine incorporation and downregulated smooth muscle-specific myosin heavy chain and alpha-actin synthesis in rat aortic SMC. These effects were not inhibited by antibodies to platelet-derived growth factor (PDGF)-BB or PDGF-AB or with a PDGF beta-receptor subunit. Treatment with PDGF-BB (at a concentration found in ECCM), PDGF-AA, basic fibroblast growth factor, endothelin-1, or transforming growth factor-beta did not reproduce these effects. The ECCM activities were sensitive to heat and trypsinization, were >30 kDa in molecular mass, and bound weakly to heparin-Sepharose. Our data indicate that cultured endothelial cells produce a factor(s) that downregulates contractile protein expression in SMC, which may contribute to SMC dedifferentiation and proliferation.

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Extracellular matrix proteins differentially regulate airway smooth muscle phenotype and function

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00331.2006 ◽

2007 ◽

Vol 292 (6) ◽

pp. L1405-L1413 ◽

Cited By ~ 80

Author(s):

Bart G. J. Dekkers ◽

Dedmer Schaafsma ◽

S. Adriaan Nelemans ◽

Johan Zaagsma ◽

Herman Meurs

Keyword(s):

Smooth Muscle ◽

Protein Expression ◽

Airway Smooth Muscle ◽

Airway Remodeling ◽

Negative Control ◽

Collagen I ◽

Contractile Protein ◽

Chronic Obstructive ◽

Ecm Proteins ◽

And Function

Changes in the ECM and increased airway smooth muscle (ASM) mass are major contributors to airway remodeling in asthma and chronic obstructive pulmonary disease. It has recently been demonstrated that ECM proteins may differentially affect proliferation and expression of phenotypic markers of cultured ASM cells. In the present study, we investigated the functional relevance of ECM proteins in the modulation of ASM contractility using bovine tracheal smooth muscle (BTSM) preparations. The results demonstrate that culturing of BSTM strips for 4 days in the presence of fibronectin or collagen I depressed maximal contraction (Emax) both for methacholine and KCl, which was associated with decreased contractile protein expression. By contrast, both fibronectin and collagen I increased proliferation of cultured BTSM cells. Similar effects were observed for PDGF. Moreover, PDGF augmented fibronectin- and collagen I-induced proliferation in an additive fashion, without an additional effect on contractility or contractile protein expression. The fibronectin-induced depression of contractility was blocked by the integrin antagonist Arg-Gly-Asp-Ser (RGDS) but not by its negative control Gly-Arg-Ala-Asp-Ser-Pro (GRADSP). Laminin, by itself, did not affect contractility or proliferation but reduced the effects of PDGF on these parameters. Strong relationships were found between the ECM-induced changes in Emax in BTSM strips and their proliferative responses in BSTM cells and for Emax and contractile protein expression. Our results indicate that ECM proteins differentially regulate both phenotype and function of intact ASM.

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