Actin Cytoskeleton Dynamics Promotes Leptin-Induced Vascular Smooth Muscle Hypertrophy via RhoA/ROCK- and Phosphatidylinositol 3-Kinase/Protein Kinase B-Dependent Pathways

Zeidan, Asad; Paylor, Ben; Steinhoff, Karly J.; Javadov, Sabzali; Rajapurohitam, Venkatesh; Chakrabarti, Subrata; Karmazyn, Morris

doi:10.1124/jpet.107.122440

Cited by 44 publications

(49 citation statements)

References 39 publications

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“…13,14,27 Furthermore, the effect of actin polymerization for gene transcription via MRTF has been shown to be involved in multiple and SMCs. 10,[28][29][30] Herein, we demonstrate that the ratio of filamentous to globular actin is dramatically decreased in phenotypically modulated SMCs. By stabilizing actin filaments in cultured cells with Jasp, the expression of smooth muscle markers can be partially restored already after 24 hours of treatment and further induced by 72 hours.…”

Section: Discussionmentioning

confidence: 65%

Regulation of Smooth Muscle Dystrophin and Synaptopodin 2 Expression by Actin Polymerization and Vascular Injury

Turczyńska

Swärd

Hien

et al. 2015

ATVB

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Objective-Actin dynamics in vascular smooth muscle is known to regulate contractile differentiation and may play a role in the pathogenesis of vascular disease. However, the list of genes regulated by actin polymerization in smooth muscle remains incomprehensive. Thus, the objective of this study was to identify actin-regulated genes in smooth muscle and to demonstrate the role of these genes in the regulation of vascular smooth muscle phenotype. Approach and Results-Mouse aortic smooth muscle cells were treated with an actin-stabilizing agent, jasplakinolide, and analyzed by microarrays. Several transcripts were upregulated including both known and previously unknown actin-regulated genes. Dystrophin and synaptopodin 2 were selected for further analysis in models of phenotypic modulation and vascular disease. These genes were highly expressed in differentiated versus synthetic smooth muscle and their expression was promoted by the transcription factors myocardin and myocardin-related transcription factor A. Furthermore, the expression of both synaptopodin 2 and dystrophin was significantly reduced in balloon-injured human arteries. Finally, using a dystrophin mutant mdx mouse and synaptopodin 2 knockdown, we demonstrate that these genes are involved in the regulation of smooth muscle differentiation and function. Conclusions-This

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Section: Discussionmentioning

confidence: 65%

Regulation of Smooth Muscle Dystrophin and Synaptopodin 2 Expression by Actin Polymerization and Vascular Injury

Turczyńska

Swärd

Hien

et al. 2015

ATVB

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“…This effect was attenuated by Latrunculin B, which binds actin monomers, preventing polymerization and effective disruption of actin filament formation. Previous work has demonstrated the importance of actin remodeling in hypertrophy of cardiomyocytes (34) and vascular smooth muscle cells (13). Stress fiber formation is typically mediated via RhoA-dependent signaling (12).…”

Section: Discussionmentioning

confidence: 99%

“…Upon stimulation of Rho/ROCK, phosphorylation of the actin depolymerizing factor cofilin ensues, resulting in its inactivation and inability to sever filamentous-actin (F-actin) (12). Furthermore, modulation of cofilin activity via the Rho/ROCK pathway was recently shown to regulate cardiac hypertrophy (13). Because the Rho/ROCK pathway critically regulates several essential cardiac functions, the use of ROCK inhibitors has been investigated as a potential therapeutic approach (14).…”

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confidence: 98%

Regulation of MT1-MMP and MMP-2 by Leptin in Cardiac Fibroblasts Involves Rho/ROCK-Dependent Actin Cytoskeletal Reorganization and Leads to Enhanced Cell Migration

Schram

Ganguly

et al. 2011

Endocrinology

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Altered leptin action has been implicated in the pathophysiology of heart failure in obesity, a hallmark of which is extracellular matrix remodeling. Here, we characterize the direct influence of leptin on matrix metalloproteinase (MMP) activity in primary adult rat cardiac fibroblasts and focus on elucidating the molecular mechanisms responsible. Leptin increased expression and cell surface localization of membrane type 1 (MT1)-MMP, measured by cell surface biotinylation assay and antibody-based colorimetric detection of an exofacial epitope in intact cells. Coimmunoprecipitation analysis showed that leptin also induced the formation of a cluster of differentiation 44/MT1-MMP complex. Qualitative analysis using rhodamine-conjugated phalloidin immunofluorescence indicated that leptin stimulated actin cytoskeletal reorganization and enhanced stress fiber formation. Hence, we analyzed activation of Ras homolog gene family (Rho), member A GTPase activity and found a rapid increase in response to leptin that corresponded with increased phosphorylation of cofilin. Quantitative analysis of cytoskeleton reorganization upon separation of globular and filamentous actin by differential centrifugation confirmed the significant increase in filamentous to globular actin ratio in response to leptin, which was prevented by pharmacological inhibition of Rho (C3 transferase) or its downstream effector kinase Rho-associated coiled-coil-forming protein kinase (ROCK) (Y-27632). Inhibition of Rho or ROCK also attenuated leptin-stimulated increases in cell surface MT1-MMP content. Pro-MMP-2 is a known MT1-MMP substrate, and we observed that enhanced cell surface MT1-MMP in response to leptin resulted in enhanced extracellular activation of pro-MMP-2 measured by gelatin zymography, which was again attenuated by inhibition of Rho or ROCK. Using wound scratch assays, we observed enhanced cell migration, but not proliferation, measured by 5-bromo2'-deoxy-uridine incorporation, in response to leptin, again via a Rho-dependent signaling mechanism. Our results suggest that leptin regulates myocardial matrix remodeling by regulating the cell surface localization of MT1-MMP in adult cardiac fibroblasts via Rho/ROCK-dependent actin cytoskeleton reorganization. Subsequent pro-MMP-2 activation then contributes to stimulation of cell migration.

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“…Concentrations of circulating leptin in lean and obese individuals are between 2-10 ng/ml and 10-100 ng/ml, respectively [35]. Leptin, although primarily produced by adipocytes [9], is additionally synthesized by a plethora of tissues [11][12][13][14][15][16][17], including the heart [10]. The cardiac effects of leptin have yet to be fully elucidated, however, leptin regulates cardiomyocyte hypertrophy [13][14][15]19] hyperplasia [13], apoptosis [33] and the production of various myocardial matrix components by cardiomyocytes and cardiac fibroblasts [13,16] The underlying mechanism through which obesity contributes to the development of cardiac fibrosis in cardiovascular disease, however, remains poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Leptin regulates MMP-2, TIMP-1 and collagen synthesis via p38 MAPK in HL-1 murine cardiomyocytes

Schram

Girolamo

Madani

et al. 2010

Cellular and Molecular Biology Letters

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Abbreviations used: AP-1 -activator protein-1; ATF-2 -activating transcription factor-2; ECM -extracellular matrix; HF-heart failure; LV -left ventricular; MAPK -mitogen activated protein kinase; MMP -matrix metalloproteinase; mRNA-messenger ribonucleic acid; PBS -phosphate buffered saline; PCR -polymerase chain reaction; TIMP-tissue inhibitor of metalloproteinase Abstract: A clear association between obesity and heart failure exists and a significant role for leptin, the product of the obese gene, has been suggested. One aspect of myocardial remodeling which characterizes heart failure is a disruption in the balance of extracellular matrix synthesis and degradation. Here we investigated the effects of leptin on matrix metalloproteinase (MMP) activity, tissue inhibitor of metalloproteinase (TIMP) expression, as well as collagen synthesis in HL-1 cardiac muscle cells. Gelatin zymographic analysis of MMP activity in conditioned media showed that leptin enhanced MMP-2 activity in a dose-and time-dependent manner. Leptin is known to stimulate phosphorylation of p38 MAPK in cardiac cells and utilization of the p38 MAPK inhibitor, SB203580, demonstrated that this kinase also plays a role in regulating several extracellular matrix components, such that inhibition of p38 MAPK signaling prevented the leptin-induced increase in MMP-2 activation. We also observed that leptin enhanced collagen synthesis determined by both proline incorporation and picrosirius red staining of conditioned media. Pro-collagen type-I and pro-collagen type-III expression, measured by real-time PCR and Western blotting were also increased by leptin, effects which were again attenuated by SB203580. In summary, these results demonstrate the potential for leptin to play a role in mediating myocardial ECM remodeling and that the p38 MAPK pathway plays an important role in mediating these effects.

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Actin Cytoskeleton Dynamics Promotes Leptin-Induced Vascular Smooth Muscle Hypertrophy via RhoA/ROCK- and Phosphatidylinositol 3-Kinase/Protein Kinase B-Dependent Pathways

Cited by 44 publications

References 39 publications

Regulation of Smooth Muscle Dystrophin and Synaptopodin 2 Expression by Actin Polymerization and Vascular Injury

Regulation of Smooth Muscle Dystrophin and Synaptopodin 2 Expression by Actin Polymerization and Vascular Injury

Regulation of MT1-MMP and MMP-2 by Leptin in Cardiac Fibroblasts Involves Rho/ROCK-Dependent Actin Cytoskeletal Reorganization and Leads to Enhanced Cell Migration

Leptin regulates MMP-2, TIMP-1 and collagen synthesis via p38 MAPK in HL-1 murine cardiomyocytes

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