| 1. |
- Alajbegovic, Azra, et al.
(författare)
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Regulation of microRNA expression in vascular smooth muscle by MRTF-A and actin polymerization
- 2017
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Ingår i: Biochimica et Biophysica Acta - Molecular Cell Research. - : Elsevier BV. - 0167-4889. ; 1864:6, s. 1088-1098
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Tidskriftsartikel (refereegranskat)abstract
- The dynamic properties of the actin cytoskeleton in smooth muscle cells play an important role in a number of cardiovascular disease states. The state of actin does not only mediate mechanical stability and contractile function but can also regulate gene expression via myocardin related transcription factors (MRTFs). These transcriptional co-activators regulate genes encoding contractile and cytoskeletal proteins in smooth muscle. Regulation of small non-coding microRNAs (miRNAs) by actin polymerization may mediate some of these effects. MiRNAs are short non-coding RNAs that modulate gene expression by post-transcriptional regulation of target messenger RNA.In this study we aimed to determine a profile of miRNAs that were 1) regulated by actin/MRTF-A, 2) associated with the contractile smooth muscle phenotype and 3) enriched in muscle cells. This analysis was performed using cardiovascular disease-focused miRNA arrays in both mouse and human cells. The potential clinical importance of actin polymerization in aortic aneurysm was evaluated using biopsies from mildly dilated human thoracic aorta in patients with stenotic tricuspid or bicuspid aortic valve.By integrating information from multiple qPCR based miRNA arrays we identified a group of five miRNAs (miR-1, miR-22, miR-143, miR-145 and miR-378a) that were sensitive to actin polymerization and MRTF-A overexpression in both mouse and human vascular smooth muscle. With the exception of miR-22, these miRNAs were also relatively enriched in striated and/or smooth muscle containing tissues. Actin polymerization was found to be dramatically reduced in the aorta from patients with mild aortic dilations. This was associated with a decrease in actin/MRTF-regulated miRNAs.In conclusion, the transcriptional co-activator MRTF-A and actin polymerization regulated a subset of miRNAs in vascular smooth muscle. Identification of novel miRNAs regulated by actin/MRTF-A may provide further insight into the mechanisms underlying vascular disease states, such as aortic aneurysm, as well as novel ideas regarding therapeutic strategies. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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| 2. |
- Grossi, Mario, et al.
(författare)
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Pyk2 inhibition promotes contractile differentiation in arterial smooth muscle
- 2017
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Ingår i: Journal of Cellular Physiology. - : Wiley. - 0021-9541. ; 232:11, s. 3088-3102
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Tidskriftsartikel (refereegranskat)abstract
- Modulation from contractile to synthetic phenotype of vascular smooth muscle cells is a central process in disorders involving compromised integrity of the vascular wall. Phenotype modulation has been shown to include transition from voltage-dependent toward voltage-independent regulation of the intracellular calcium level, and inhibition of non-voltage dependent calcium influx contributes to maintenance of the contractile phenotype. One possible mediator of calcium-dependent signaling is the FAK-family non-receptor protein kinase Pyk2, which is activated by a number of stimuli in a calcium-dependent manner. We used the Pyk2 inhibitor PF-4594755 and Pyk2 siRNA to investigate the role of Pyk2 in phenotype modulation in rat carotid artery smooth muscle cells and in cultured intact arteries. Pyk2 inhibition promoted the expression of smooth muscle markers at the mRNA and protein levels under stimulation by FBS or PDGF-BB and counteracted phenotype shift in cultured intact carotid arteries and balloon injury ex vivo. During long-term (24–96 hr) treatment with PF-4594755, smooth muscle markers increased before cell proliferation was inhibited, correlating with decreased KLF4 expression and differing from effects of MEK inhibition. The Pyk2 inhibitor reduced Orai1 and preserved SERCA2a expression in carotid artery segments in organ culture, and eliminated the inhibitory effect of PDGF stimulation on L-type calcium channel and large-conductance calcium-activated potassium channel expression in carotid cells. Basal intracellular calcium level, calcium wave activity, and store-operated calcium influx were reduced after Pyk2 inhibition of growth-stimulated cells. Pyk2 inhibition may provide an interesting approach for preserving vascular smooth muscle differentiation under pathophysiological conditions.
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| 3. |
- Madsen, Marie, et al.
(författare)
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Uremia modulates the phenotype of aortic smooth muscle cells
- 2017
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Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150. ; 257, s. 64-70
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims Chronic kidney disease leads to uremia and markedly accelerates atherosclerosis. Phenotypic modulation of smooth muscle cells (SMCs) in the arterial media plays a key role in accelerating atherogenesis. The aim of this study was to investigate whether uremia per se modulates the phenotype of aortic SMCs in vivo. Methods Moderate uremia was induced by 5/6 nephrectomy in apolipoprotein E knockout (ApoE-/-) and wildtype C57Bl/6 mice. Plasma analysis, gene expression, histology, and myography were used to determine uremia-mediated changes in the arterial wall. Results Induction of moderate uremia in ApoE-/- mice increased atherosclerosis in the aortic arch en face 1.6 fold (p = 0.04) and induced systemic inflammation. Based on histological analyses of aortic root sections, uremia increased the medial area, while there was no difference in the content of elastic fibers or collagen in the aortic media. In the aortic arch, mRNA and miRNA expression patterns were consistent with a uremia-mediated phenotypic modulation of SMCs; e.g. downregulation of myocardin, α-smooth muscle actin, and transgelin; and upregulation of miR146a. Notably, these expression patterns were observed after acute (2 weeks) and chronic (19 and 30 weeks) uremia, both under normo- and hypercholesterolemic settings. Functionally, aortic constriction was decreased in uremic as compared to non-uremic aorta segments, as measured by myography. Conclusions Uremia modulates the phenotype of aortic SMCs as determined by mRNA/miRNA expression, an increased medial area, and decreased aortic contractility. We propose that this phenotypic modulation of SMCs precedes the acceleration of atherosclerosis observed in uremic mice.
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