Acquisition of the contractile phenotype by murine arterial smooth muscle cells depends on the Mir143/145 gene cluster
Thomas Boettger, … , Lutz Hein, Thomas Braun
Thomas Boettger, … , Lutz Hein, Thomas Braun
Published August 17, 2009
Citation Information: J Clin Invest. 2009;119(9):2634-2647. https://doi.org/10.1172/JCI38864.
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Research Article

Acquisition of the contractile phenotype by murine arterial smooth muscle cells depends on the Mir143/145 gene cluster

Abstract

VSMCs respond to changes in the local environment by adjusting their phenotype from contractile to synthetic, a phenomenon known as phenotypic modulation or switching. Failure of VSMCs to acquire and maintain the contractile phenotype plays a key role in a number of major human diseases, including arteriosclerosis. Although several regulatory circuits that control differentiation of SMCs have been identified, the decisive mechanisms that govern phenotypic modulation remain unknown. Here, we demonstrate that the mouse miR-143/145 cluster, expression of which is confined to SMCs during development, is required for VSMC acquisition of the contractile phenotype. VSMCs from miR-143/145–deficient mice were locked in the synthetic state, which incapacitated their contractile abilities and favored neointimal lesion development. Unbiased high-throughput, quantitative, mass spectrometry–based proteomics using reference mice labeled with stable isotopes allowed identification of miR-143/145 targets; these included angiotensin-converting enzyme (ACE), which might affect both the synthetic phenotype and contractile functions of VSMCs. Pharmacological inhibition of either ACE or the AT1 receptor partially reversed vascular dysfunction and normalized gene expression in miR-143/145–deficient mice. We conclude that manipulation of miR-143/145 expression may offer a new approach for influencing vascular repair and attenuating arteriosclerotic pathogenesis.

Authors

Thomas Boettger, Nadine Beetz, Sawa Kostin, Johanna Schneider, Marcus Krüger, Lutz Hein, Thomas Braun

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Figure 4

In vitro evaluation of contractile properties of isolated femoral artery rings mounted in a myograph.

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In vitro evaluation of contractile properties of isolated femoral artery...
(A) Vessel contraction induced by extracellular potassium was reduced to 61% of the WT response (n = 12 WT and n = 8 KO vessels, *P < 0.05). No change in contraction after potassium-induced depolarization was observed after treatment with captopril (n = 8 WT and n = 9 KO vessels). (B) Vessel contraction induced by angiotensin II was significantly blunted in mutant arteries. Pretreatment with captopril significantly improved angiotensin II–induced contractile responses (n = 12 WT and n = 9 KO vessels of untreated animals, ***P < 0.0001, KO untreated vs. WT untreated; n = 8 WT and n = 9 KO vessels of captopril-treated animals, #P < 0.05 KO treated vs. KO untreated). (C and D) Isolated arteries stimulated with increasing concentrations of phenylephrine. Arrows indicate applications of phenylephrine. (D) Statistical analysis of phenylephrine and captopril responses. Captopril treatment improved responses of the KO vessels (n = 12 WT and n = 8 KO vessels of untreated animals, *P < 0.05, ***P < 0.001, KO untreated vs. WT untreated; n = 8 WT and n = 0 KO vessels of captopril-treated animals, ##P < 0.01 KO treated vs. KO untreated). (E) Contractile responses to phenylephrine stimulation of mesenteric arteries. Arterial rings from KO animals showed a significant enhancement in contractility after AT1 receptor blockade by losartan (n = 7 WT and n = 8 KO vessels from untreated animals, ***P < 0.001, KO untreated vs. WT untreated; n = 10 WT and n = 8 KO vessels from losartan-treated animals, ##P < 0.01, ###P > 0.001, KO treated vs. KO untreated). (F) pCa-force relationships in skinned femoral arteries. Maximal Ca2+-induced contraction was blunted in KO arteries, and the pEC50 values significantly shifted leftward in KO skinned arteries (n = 12 WT and n = 8 KO vessels, *P < 0.05, **P < 0.01, ***P < 0.001, KO vs. WT). Error bars indicate ± SEM.