scholarly journals A Loss of Nuclear—Cytoskeletal Interactions in Vascular Smooth Muscle Cell Differentiation Induced by a Micro-Grooved Collagen Substrate Enabling the Modeling of an In Vivo Cell Arrangement

2021 ◽  
Vol 8 (9) ◽  
pp. 124
Author(s):  
Kazuaki Nagayama

Vascular smooth muscle cells (VSMCs) remodel vascular walls actively owing to mechanical cues and dedifferentiate to the synthetic phenotype from contractile phenotype in pathological conditions. It is crucial to clarify the mechanisms behind the VSMC phenotypic transition for elucidating their role in the vascular adaptation and repair and for designing engineered tissues. We recently developed novel micro-grooved collagen substrates with “wavy wrinkle” grooves to induce cell–substrate adhesion, morphological polarization, and a tissue-like cell arrangement with cytoskeletal rearrangements similar to those in vascular tissue in vivo. We found that cultivation with this micro-grooved collagen significantly induced VSMC contractile differentiation. Nonetheless, the detailed mechanism underlying the promotion of such VSMC differentiation by micro-grooved collagen has not been clarified yet. Here, we investigated the detailed mechanism of the cell arrangement into a tissue and contractile-differentiation improvement by our micro-grooved collagen substrates in terms of nuclear–cytoskeletal interactions that possibly affect the nuclear mechanotransduction involved in the activation of transcription factors. We found that VSMCs on micro-grooved collagen manifested significant cell arrangement into a tissue and nucleus slimming with a volume reduction in response to the remodeling of the actin cytoskeleton, with consequent inhibition of nuclear shuttling of a transcriptional coactivator, Yes-associated protein (YAP), and improved contractile differentiation. Furthermore, VSMC nuclei rarely deformed during macroscopic cell stretching and featured a loss of nesprin-1–mediated nuclear–cytoskeletal interactions. These results indicate that our micro-grooved collagen induces a cell alignment mimicking in vivo VSMC tissue and promotes contractile differentiation. In such processes of contractile differentiation, mechanical interaction between the nucleus and actin cytoskeleton may diminish to prevent a nuclear disturbance from the excess mechanical stress that might be essential for maintaining vascular functions.

2010 ◽  
Vol 298 (6) ◽  
pp. C1481-C1488 ◽  
Author(s):  
Xiaojun Liu ◽  
Yunhui Cheng ◽  
Jian Yang ◽  
Thomas J. Krall ◽  
Yuqing Huo ◽  
...  

It is well established that vascular smooth muscle cell (VSMC) apoptosis and proliferation are critical cellular events in a variety of human vascular diseases. However, the molecular mechanisms involved in controlling VSMC apoptosis and proliferation are still unclear. In the current study, we have found that programmed cell death 4 (PDCD4) is significantly downregulated in balloon-injured rat carotid arteries in vivo and in platelet-derived growth factor-stimulated VSMCs in vitro. Overexpression of PDCD4 via adenovirus (Ad-PDCD4) increases VSMC apoptosis in an apoptotic model induced by serum deprivation. In contrast, VSMC apoptosis is significantly decreased by knockdown of PDCD4 via its small interfering RNA. In the rat carotid arteries in vivo, VSMC apoptosis is increased by Ad-PDCD4. We have further identified that activator protein 1 is a downstream signaling molecule of PDCD4 that is associated with PDCD4-mediated effects on VSMC apoptosis. In addition, VSMC proliferation was inhibited by overexpression of PDCD4. The current study has identified, for the first time, that PDCD4 is an essential regulator of VSMC apoptosis and proliferation. The downregulation of PDCD4 expression in diseased vascular walls may be responsible for the imbalance of VSMC proliferation and apoptosis. The results indicate that PDCD4 may be a new therapeutic target in proliferative vascular diseases.


Blood ◽  
1993 ◽  
Vol 82 (1) ◽  
pp. 66-76 ◽  
Author(s):  
MC Galmiche ◽  
VE Koteliansky ◽  
J Briere ◽  
P Herve ◽  
P Charbord

In human long-term marrow cultures connective tissue-forming stromal cells are an essential cellular component of the adherent layer where granulomonocytic progenitors are generated from week 2 onward. We have previously found that most stromal cells in confluent cultures were stained by monoclonal antibodies directed against smooth muscle- specific actin isoforms. The present study was carried out to evaluate the time course of alpha-SM-positive stromal cells and to search for other cytoskeletal proteins specific for smooth muscle cells. It was found that the expression of alpha-SM in stromal cells was time dependent. Most of the adherent spindle-shaped, vimentin-positive stromal cells observed during the first 2 weeks of culture were alpha- SM negative. On the contrary, from week 3 to week 7, most interdigitated stromal cells contained stress fibers whose backbone was made of alpha-SM-positive microfilaments. In addition, in confluent cultures, other proteins specific for smooth muscle were detected: metavinculin, h-caldesmon, smooth muscle myosin heavy chains, and calponin. This study confirms the similarity between stromal cells and smooth muscle cells. Moreover, our results reveal that cells in vivo with the phenotype closest to that of stromal cells are immature fetal smooth muscle cells and subendothelial intimal smooth muscle cells; a cell subset with limited development following birth but extensively recruited in atherosclerotic lesions. Stromal cells very probably derive from mesenchymal cells that differentiate along this distinctive vascular smooth muscle cell pathway. In humans, this differentiation seems crucial for the maintenance of granulomonopoiesis. These in vitro studies were completed by examination of trephine bone marrow biopsies from adults without hematologic abnormalities. These studies revealed the presence of alpha-SM-positive cells at diverse locations: vascular smooth muscle cells in the media of arteries and arterioles, pericytes lining capillaries, myoid cells lining sinuses at the abluminal side of endothelial cells or found within the hematopoietic logettes, and endosteal cells lining bone trabeculae. More or less mature cells of the granulocytic series were in intimate contact with the thin cytoplasmic extensions of myoid cells. Myoid cells may be the in vivo counterpart of stromal cells with the above-described vascular smooth muscle phenotype.


2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Nahed El-Najjar ◽  
Rashmi P. Kulkarni ◽  
Nancy Nader ◽  
Rawad Hodeify ◽  
Khaled Machaca

Diabetes is a complex disease that is characterized with hyperglycemia, dyslipidemia, and insulin resistance. These pathologies are associated with significant cardiovascular implications that affect both the macro- and microvasculature. It is therefore important to understand the effects of various pathologies associated with diabetes on the vasculature. Here we directly test the effects of hyperglycemia on vascular smooth muscle (VSM) Ca2+signaling in an isolated in vitro system using the A7r5 rat aortic cell line as a model. We find that prolonged exposure of A7r5 cells to hyperglycemia (weeks) is associated with changes to Ca2+signaling, including most prominently an inhibition of the passive ER Ca2+leak and the sarcoplasmic reticulum Ca2+-ATPase (SERCA). To translate these findings to the in vivo condition, we used primary VSM cells from normal and diabetic subjects and find that only the inhibition of the ER Ca2+leaks replicates in cells from diabetic donors. These results show that prolonged hyperglycemia in isolation alters the Ca2+signaling machinery in VSM cells. However, these alterations are not readily translatable to the whole organism situation where alterations to the Ca2+signaling machinery are different.


2013 ◽  
Vol 99 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Keith Allen-Redpath ◽  
Ou Ou ◽  
John H. Beattie ◽  
In-Sook Kwun ◽  
Jorg Feldmann ◽  
...  

1994 ◽  
Vol 269 (11) ◽  
pp. 8504-8509
Author(s):  
K.A. Pritchard ◽  
M.K. O'Banion ◽  
J.M. Miano ◽  
N. Vlasic ◽  
U.G. Bhatia ◽  
...  

2005 ◽  
Vol 108 (6) ◽  
pp. 523-530 ◽  
Author(s):  
Giovanna CASTOLDI ◽  
Serena REDAELLI ◽  
Willy M. M. van de GREEF ◽  
Cira R. T. di GIOIA ◽  
Giuseppe BUSCA ◽  
...  

Ang II (angiotensin II) has multiple effects on vascular smooth muscle cells through the modulation of different classes of genes. Using the mRNA differential-display method to investigate gene expression in rat aortic smooth muscle cells in culture in response to 3 h of Ang II stimulation, we observed that Ang II down-regulated the expression of a member of the family of transmembrane receptors for Wnt proteins that was identified as Fzd2 [Fzd (frizzled)-2 receptor]. Fzds are a class of highly conserved genes playing a fundamental role in the developmental processes. In vitro, time course experiments demonstrated that Ang II induced a significant increase (P<0.05) in Fzd2 expression after 30 min, whereas it caused a significant decrease (P<0.05) in Fzd2 expression at 3 h. A similar rapid up-regulation after Ang II stimulation for 30 min was evident for TGFβ1 (transforming growth factor β1; P<0.05). To investigate whether Ang II also modulated Fzd2 expression in vivo, exogenous Ang II was administered to Sprague–Dawley rats (200 ng·kg−1 of body weight·min−1; subcutaneously) for 1 and 4 weeks. Control rats received normal saline. After treatment, systolic blood pressure was significantly higher (P<0.01), whereas plasma renin activity was suppressed (P<0.01) in Ang II- compared with the saline-treated rats. Ang II administration for 1 week did not modify Fzd2 expression in aorta of Ang II-treated rats, whereas Ang II administration for 4 weeks increased Fzd2 mRNA expression (P<0.05) in the tunica media of the aorta, resulting in a positive immunostaining for fibronectin at this time point. In conclusion, our data demonstrate that Ang II modulates Fzd2 expression in aortic smooth muscle cells both in vitro and in vivo.


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