A preliminary proteomic evaluation of smooth muscle cells in thoracic aortic aneurysms

Background Sporadic non-syndromic thoracic aortic aneurysms (SNSTAAs) are less well understood than familial non-syndromic or syndromic ones. The study aimed at defining the peculiar morphologic and molecular changes occurring in the media layer of SNSTAAs. Design This study was based on a single centre design. Methods Media layer samples taken from seven carefully selected SNSTAAs and seven reference patients (controls) were investigated via quantitative polymerase chain reaction, proteomics-bioinformatics, immunoblotting, quantitative histology, and immunohistochemistry/immunofluorescence. Results In SNSTAAs media, aortic smooth muscle cells numbers were halved due to an apoptotic process coupled with a negligible cell proliferation. Cystathionine γ-lyase was diffusely up-regulated. Surviving aortic smooth muscle cells exhibited diverging phenotypes: in inner- and outer-media contractile cells prevailed, having higher contents of smooth-muscle-α-actin holoprotein (45-kDa) and of caspase-3-cleaved smooth-muscle-α-actin 25-kDa fragments; in mid-media, aortic smooth muscle cells exhibited a synthetic/secretor phenotype, down-regulating vimentin, but up-regulating glial fibrillary acidic protein, trans-Golgi network 46 protein, Jagged1 (172-kDa) holoprotein, and Jagged1’s receptor Notch1. Extracellular soluble Jagged1 (42-kDa) fragments accumulated. Conclusions In SNSTAAs, there is a relentless aortic smooth muscle cells attrition caused by the up-regulated cystathionine γ-lyase. In mid-media, synthetic/secretor aortic smooth muscle cells intensify Jagged1/NOTCH1 signalling in the attempt to counterbalance the weakened aortic wall, due to aortic smooth muscle cells net loss and mechanical stress. Synthetic/secretor aortic smooth muscle cells are apoptosis-prone, and the accruing thrombin-cleaved Jagged1 fragments counteract the otherwise useful effects of Jagged1/NOTCH1 signalling, thus hampering tissue homeostasis/remodelling, and aortic smooth muscle cells adhesion, differentiation, and migration.

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Abstract 4275: TGFBR2 Mutations Reduce Expression of Contractile Proteins in Aortic Smooth Muscle Cells and Predispose Individuals to Thoracic Aortic Aneurysms and Dissections

Circulation ◽

10.1161/circ.118.suppl_18.s_856-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Sakiko Inamoto ◽

Callie Kwartler ◽

Andrea Lafont ◽

Yao Yun Liang ◽

Van Tran Fadulu ◽

...

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Matched Control ◽

Muscle Cells ◽

Contractile Proteins ◽

Aortic Aneurysms ◽

Gain Of Function ◽

Age And Gender ◽

Thoracic Aortic Aneurysms ◽

And Gender

Mutations in the TGF-β receptor type II gene ( TGFBR2 ) cause thoracic aortic aneurysms and dissections (TAAD). Studies have suggested a gain of function effect for these mutations, leading to increased TGF-β signaling in the aortic media and resulting in vascular disease. We sought to characterize the phenotype of smooth muscle cells (SMCs) harboring heterozygous missense TGFBR2 mutations and our data suggest that instead of a gain of function, TGFBR2 mutations cause TAAD as a result of a loss of function resulting in defective SMC differentiation. Using primary aortic SMCs from patients harboring TGFBR2 mutations (n=4), we show a global decrease in expression of SMC contractile proteins ( ACTA2 , MYH11 , CNN1 , SMTN , TPM1 , TPM2 , p <0.001) by quantitative PCR analysis when these cells are compared with age and gender matched control SMCs (n=4), along with no change in the expression of cytoskeletal proteins. Consistent with the decreased expression of contractile proteins in the mutant cells, there was increased expression of S100A4, a marker of de-differentiated SMCs (p<0.001). Analysis of fixed and frozen aortas from patients with TGFBR2 mutations (n=3) confirmed decreased in vivo expression of SMC contractile proteins when compared to control aortas (n=3). In control SMCs, addition of TGF- β significantly increased the expression of the SMC contractile proteins but the TGFBR2 SMCs showed no significant increase in expression of these proteins with TGF-β stimulation. We found that fibroblasts explanted from patients with TGFBR2 mutations (n=8) consistently fail to transform into myofibroblasts as assessed by expression of SMC contractile proteins after TGF-β stimulation, when compared with age and gender matched control fibroblasts (n=8). Finally, introduction of TGFBR2 missense mutations into a mouse mesenchymal embryonic cell line that is used as a model of SMC differentiation (10T1/2 cells) disrupts the expression of contractile proteins in these cells when assessed post-differentiation. These data suggest that TGFBR2 mutations disrupt differentiation of SMCs and myofibroblasts. This is the first genetic defect identified to lead to defective SMC differentiation.

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Smooth Muscle Cells Isolated from Thoracic Aortic Aneurysms Exhibit Increased Genomic Damage, but Similar Tendency for Apoptosis

DNA and Cell Biology ◽

10.1089/dna.2012.1644 ◽

2012 ◽

Vol 31 (10) ◽

pp. 1523-1534 ◽

Cited By ~ 15

Author(s):

Ceyda Acilan ◽

Muge Serhatli ◽

Omer Kacar ◽

Zelal Adiguzel ◽

Altug Tuncer ◽

...

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Aortic Aneurysms ◽

Thoracic Aortic Aneurysms ◽

Similar Tendency ◽

Genomic Damage

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Phenotypic and Functional Changes of Endothelial and Smooth Muscle Cells in Thoracic Aortic Aneurysms

International Journal of Vascular Medicine ◽

10.1155/2016/3107879 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 13

Author(s):

Anna Malashicheva ◽

Daria Kostina ◽

Aleksandra Kostina ◽

Olga Irtyuga ◽

Irina Voronkina ◽

...

Keyword(s):

Extracellular Matrix ◽

Smooth Muscle ◽

Aortic Valve ◽

Smooth Muscle Cells ◽

Aortic Wall ◽

Muscle Cells ◽

Aortic Aneurysms ◽

Cell Phenotype ◽

Functional Markers ◽

Thoracic Aortic Aneurysms

Thoracic aortic aneurysm develops as a result of complex series of events that alter the cellular structure and the composition of the extracellular matrix of the aortic wall. The purpose of the present work was to study the cellular functions of endothelial and smooth muscle cells from the patients with aneurysms of the thoracic aorta. We studied endothelial and smooth muscle cells from aneurysms in patients with bicuspid aortic valve and with tricuspid aortic valve. The expression of key markers of endothelial (CD31, vWF, and VE-cadherin) and smooth muscle (SMA, SM22α, calponin, and vimentin) cells as well extracellular matrix and MMP activity was studied as well as and apoptosis and cell proliferation. Expression of functional markers of endothelial and smooth muscle cells was reduced in patient cells. Cellular proliferation, migration, and synthesis of extracellular matrix proteins are attenuated in the cells of the patients. We show for the first time that aortic endothelial cell phenotype is changed in the thoracic aortic aneurysms compared to normal aortic wall. In conclusion both endothelial and smooth muscle cells from aneurysms of the ascending aorta have downregulated specific cellular markers and altered functional properties, such as growth rate, apoptosis induction, and extracellular matrix synthesis.

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