Cyclic strain upregulates VEGF and attenuates proliferation of vascular smooth muscle cells

Persistent Link:
http://hdl.handle.net/10150/610259
Title:
Cyclic strain upregulates VEGF and attenuates proliferation of vascular smooth muscle cells
Author:
Schad, Joseph; Meltzer, Kate; Hicks, Michael; Beutler, David; Cao, Thanh; Standley, Paul
Affiliation:
Department of Basic Medical Sciences, University of Arizona - Phoenix, AZ, USA; Department of Biomedical Sciences, Midwestern University - Glendale, AZ, USA; Department of Molecular and Cell Biology, Arizona State University - Tempe, AZ, USA
Issue Date:
2011
Publisher:
BioMed Central
Citation:
Schad et al. Vascular Cell 2011, 3:21 http://www.vascularcell.com/content/3/1/21
Journal:
Vascular Cell
Rights:
© 2011 Schad et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0)
Collection Information:
This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at repository@u.library.arizona.edu.
Abstract:
OBJECTIVE:Vascular smooth muscle cell (VSMC) hypertrophy and proliferation occur in response to strain-induced local and systemic inflammatory cytokines and growth factors which may contribute to hypertension, atherosclerosis, and restenosis. We hypothesize VSMC strain, modeling normotensive arterial pressure waveforms in vitro, results in attenuated proliferative and increased hypertrophic responses 48 hrs post-strain.METHODS:Using Flexcell Bioflex Systems we determined the morphological, hyperplastic and hypertrophic responses of non-strained and biomechanically strained cultured rat A7R5 VSMC. We measured secretion of nitric oxide, key cytokine/growth factors and intracellular mediators involved in VSMC proliferation via fluorescence spectroscopy and protein microarrays. We also investigated the potential roles of VEGF on VSMC strain-induced proliferation.RESULTS:Protein microarrays revealed significant increases in VEGF secretion in response to 18 hours mechanical strain, a result that ELISA data corroborated. Apoptosis-inducing nitric oxide (NO) levels also increased 43% 48 hrs post-strain. Non-strained cells incubated with exogenous VEGF did not reproduce the antimitogenic effect. However, anti-VEGF reversed the antimitogenic effect of mechanical strain. Antibody microarrays of strained VSMC lysates revealed MEK1, MEK2, phospo-MEK1T385, T291, T298, phospho-Erk1/2T202+Y204/T185+T187, and PKC isoforms expression were universally increased, suggesting a proliferative/inflammatory signaling state. Conversely, VSMC strain decreased expression levels of Cdk1, Cdk2, Cdk4, and Cdk6 by 25-50% suggesting a partially inhibited proliferative signaling cascade.CONCLUSIONS:Subjecting VSMC to cyclic biomechanical strain in vitro promotes cell hypertrophy while attenuating cellular proliferation. We also report an upregulation of MEK and ERK activation suggestive of a proliferative phenotype. Hhowever, the proliferative response appears to be aborogated by enhanced antimitogenic cytokine VEGF, NO secretion and downregulation of Cdk expression. Although exogenous VEGF alone is not sufficient to promote the quiescent VSMC phenotype, we provide evidence suggesting that strain is a necessary component to induce VSMC response to the antimitogenic effects of VEGF. Taken together these data indicate that VEGF plays a critical role in mechanical strain-induced VSMC proliferation and vessel wall remodeling. Whether VEGF and/or NO inhibit signaling distal to Erk 1/2 is currently under investigation.
EISSN:
 2045-824X
DOI:
10.1186/2045-824X-3-21
Keywords:
blood vessels; cell proliferation; biomechanical strain; VEGF; vascular smooth muscle; cytokines; nitric oxide
Version:
Final published version
Additional Links:
http://www.vascularcell.com/content/3/1/21

Full metadata record

DC FieldValue Language
dc.contributor.authorSchad, Josephen
dc.contributor.authorMeltzer, Kateen
dc.contributor.authorHicks, Michaelen
dc.contributor.authorBeutler, Daviden
dc.contributor.authorCao, Thanhen
dc.contributor.authorStandley, Paulen
dc.date.accessioned2016-05-20T09:02:27Z-
dc.date.available2016-05-20T09:02:27Z-
dc.date.issued2011en
dc.identifier.citationSchad et al. Vascular Cell 2011, 3:21 http://www.vascularcell.com/content/3/1/21en
dc.identifier.doi10.1186/2045-824X-3-21en
dc.identifier.urihttp://hdl.handle.net/10150/610259-
dc.description.abstractOBJECTIVE:Vascular smooth muscle cell (VSMC) hypertrophy and proliferation occur in response to strain-induced local and systemic inflammatory cytokines and growth factors which may contribute to hypertension, atherosclerosis, and restenosis. We hypothesize VSMC strain, modeling normotensive arterial pressure waveforms in vitro, results in attenuated proliferative and increased hypertrophic responses 48 hrs post-strain.METHODS:Using Flexcell Bioflex Systems we determined the morphological, hyperplastic and hypertrophic responses of non-strained and biomechanically strained cultured rat A7R5 VSMC. We measured secretion of nitric oxide, key cytokine/growth factors and intracellular mediators involved in VSMC proliferation via fluorescence spectroscopy and protein microarrays. We also investigated the potential roles of VEGF on VSMC strain-induced proliferation.RESULTS:Protein microarrays revealed significant increases in VEGF secretion in response to 18 hours mechanical strain, a result that ELISA data corroborated. Apoptosis-inducing nitric oxide (NO) levels also increased 43% 48 hrs post-strain. Non-strained cells incubated with exogenous VEGF did not reproduce the antimitogenic effect. However, anti-VEGF reversed the antimitogenic effect of mechanical strain. Antibody microarrays of strained VSMC lysates revealed MEK1, MEK2, phospo-MEK1T385, T291, T298, phospho-Erk1/2T202+Y204/T185+T187, and PKC isoforms expression were universally increased, suggesting a proliferative/inflammatory signaling state. Conversely, VSMC strain decreased expression levels of Cdk1, Cdk2, Cdk4, and Cdk6 by 25-50% suggesting a partially inhibited proliferative signaling cascade.CONCLUSIONS:Subjecting VSMC to cyclic biomechanical strain in vitro promotes cell hypertrophy while attenuating cellular proliferation. We also report an upregulation of MEK and ERK activation suggestive of a proliferative phenotype. Hhowever, the proliferative response appears to be aborogated by enhanced antimitogenic cytokine VEGF, NO secretion and downregulation of Cdk expression. Although exogenous VEGF alone is not sufficient to promote the quiescent VSMC phenotype, we provide evidence suggesting that strain is a necessary component to induce VSMC response to the antimitogenic effects of VEGF. Taken together these data indicate that VEGF plays a critical role in mechanical strain-induced VSMC proliferation and vessel wall remodeling. Whether VEGF and/or NO inhibit signaling distal to Erk 1/2 is currently under investigation.en
dc.language.isoenen
dc.publisherBioMed Centralen
dc.relation.urlhttp://www.vascularcell.com/content/3/1/21en
dc.rights© 2011 Schad et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0)en
dc.subjectblood vesselsen
dc.subjectcell proliferationen
dc.subjectbiomechanical strainen
dc.subjectVEGFen
dc.subjectvascular smooth muscleen
dc.subjectcytokinesen
dc.subjectnitric oxideen
dc.titleCyclic strain upregulates VEGF and attenuates proliferation of vascular smooth muscle cellsen
dc.typeArticleen
dc.identifier.eissn 2045-824Xen
dc.contributor.departmentDepartment of Basic Medical Sciences, University of Arizona - Phoenix, AZ, USAen
dc.contributor.departmentDepartment of Biomedical Sciences, Midwestern University - Glendale, AZ, USAen
dc.contributor.departmentDepartment of Molecular and Cell Biology, Arizona State University - Tempe, AZ, USAen
dc.identifier.journalVascular Cellen
dc.description.collectioninformationThis item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
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