scholarly journals Differences in genetic signaling, and not mechanical properties of the wall, are linked to ascending aortic aneurysms in fibulin-4 knockout mice

2015 ◽  
Vol 309 (1) ◽  
pp. H103-H113 ◽  
Author(s):  
Jungsil Kim ◽  
Jesse D. Procknow ◽  
Hiromi Yanagisawa ◽  
Jessica E. Wagenseil
Keyword(s):  
Gene Expression ◽  
Matrix Protein ◽  
Mechanical Response ◽  
Aortic Aneurysms ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Newborn Mice ◽  
Thoracic Aortic Aneurysms ◽  
Neutrophil Collagenase

Fibulin-4 is an extracellular matrix protein that is essential for proper assembly of arterial elastic fibers. Mutations in fibulin-4 cause cutis laxa with thoracic aortic aneurysms (TAAs). Sixty percent of TAAs occur in the ascending aorta (AA). Newborn mice lacking fibulin-4 ( Fbln4−/−) have aneurysms in the AA, but narrowing in the descending aorta (DA), and are a unique model to investigate locational differences in aneurysm susceptibility. We measured mechanical behavior and gene expression of AA and DA segments in newborn Fbln4−/− and Fbln4+/+ mice. Fbln4−/− AA has increased diameters compared with Fbln4+/+ AA and Fbln4−/− DA at most applied pressures, confirming genotypic and locational specificity of the aneurysm phenotype. When diameter compliance and tangent modulus were calculated from the mechanical data, we found few significant differences between genotypes, suggesting that the mechanical response to incremental diameter changes is similar, despite the fragmented elastic fibers in Fbln4−/− aortas. Fbln4−/− aortas showed a trend toward increased circumferential stretch, which may be transmitted to smooth muscle cells (SMCs) in the wall. Gene expression data suggest activation of pathways for SMC proliferation and inflammation in Fbln4−/− aortas compared with Fbln4+/+. Additional genes in both pathways, as well as matrix metalloprotease-8 ( Mmp8), are upregulated specifically in Fbln4−/− AA compared with Fbln4+/+ AA and Fbln4−/− DA. Mmp8 is a neutrophil collagenase that targets type 1 collagen, and upregulation may be necessary to allow diameter expansion in Fbln4−/− AA. Our results provide molecular and mechanical targets for further investigation in aneurysm pathogenesis.

scholarly journals Case Report: Occurrence of Severe Thoracic Aortic Aneurysms (Involving the Ascending, Arch, and Descending Segments) as a Result of Fibulin-4 Deficiency: A Rare Pathology With Successful Management

2021 ◽  
Vol 8 ◽  
Author(s):  
Paul Thomas ◽  
Aparna Venugopalan ◽  
Siddharth Narayanan ◽  
Thomas Mathew ◽  
Lakshmi Parvathi Deepti Cherukuwada ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Genetic Disorder ◽  
Female Child ◽  
Aortic Aneurysms ◽  
Cutis Laxa ◽  
Extracellular Matrix Protein ◽  
Successful Outcome ◽  
High Morbidity ◽  
Aortic Diseases ◽  
Thoracic Aortic Aneurysms

Aortic diseases requiring surgery in childhood are distinctive and rare. Very few reports in the literature account for the occurrence of multiple thoracic aortic aneurysms in the same pediatric patient because of a genetic cause. We report a rare occurrence of severe thoracic aortic aneurysms (involving the ascending, arch and descending aortic segments) with severe aortic insufficiency in a 7-year-old female child secondary to the extremely rare and often lethal genetic disorder, cutis laxa. She was eventually identified as a carrier of a homozygous EFEMP2 (alias FBLN4) mutation. This gene encodes the extracellular matrix protein fibulin-4, and its mutation is associated with autosomal recessive cutis laxa type 1B that leads to severe aortopathy with aneurysm formation and vascular tortuosity. Parents of the child were not known to be consanguineous. Significant symptomatic improvement in the patient could be discerned after timely intervention with the valve-sparing aortic root replacement (David V procedure) and a concomitant aortic arch replacement. This is a unique report with a successful outcome that highlights the occurrence of a rare hereditary aortopathy associated with a high morbidity and mortality, and the importance of an early diagnosis and timely management. It also offers insight to physicians in having a very broad differential and multimodal approach in handling rare pediatric cardio-pathologies with a genetic predisposition.

scholarly journals Cartilage oligomeric matrix protein is an endogenous β-arrestin-2-selective allosteric modulator of AT1 receptor counteracting vascular injury

Cell Research ◽  
2021 ◽  
Author(s):  
Yi Fu ◽  
Yaqian Huang ◽  
Zhao Yang ◽  
Yufei Chen ◽  
Jingang Zheng ◽  
...  
Keyword(s):  
Cartilage Oligomeric Matrix Protein ◽  
Matrix Protein ◽  
Therapeutic Strategies ◽  
At1 Receptor ◽  
Extracellular Matrix Protein ◽  
Binding Motif ◽  
Abdominal Aortic ◽  
Novel Therapeutic Strategies ◽  
G Protein Coupled

AbstractCompelling evidence has revealed that biased activation of G protein-coupled receptor (GPCR) signaling, including angiotensin II (AngII) receptor type 1 (AT1) signaling, plays pivotal roles in vascular homeostasis and injury, but whether a clinically relevant endogenous biased antagonism of AT1 signaling exists under physiological and pathophysiological conditions has not been clearly elucidated. Here, we show that an extracellular matrix protein, cartilage oligomeric matrix protein (COMP), acts as an endogenous allosteric biased modulator of the AT1 receptor and its deficiency is clinically associated with abdominal aortic aneurysm (AAA) development. COMP directly interacts with the extracellular N-terminus of the AT1 via its EGF domain and inhibits AT1-β-arrestin-2 signaling, but not Gq or Gi signaling, in a selective manner through allosteric regulation of AT1 intracellular conformational states. COMP deficiency results in activation of AT1a-β-arrestin-2 signaling and subsequent exclusive AAA formation in response to AngII infusion. AAAs in COMP–/– or ApoE–/– mice are rescued by AT1a or β-arrestin-2 deficiency, or the application of a peptidomimetic mimicking the AT1-binding motif of COMP. Explorations of the endogenous biased antagonism of AT1 receptor or other GPCRs may reveal novel therapeutic strategies for cardiovascular diseases.

Thrombospondin-4 knockout in hypertension protects small-artery endothelial function but induces aortic aneurysms

2016 ◽  
Vol 310 (11) ◽  
pp. H1486-H1493 ◽  
Author(s):  
Teresa Palao ◽  
Catarina Rippe ◽  
Henk van Veen ◽  
Ed VanBavel ◽  
Karl Swärd ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Matrix Protein ◽  
Pressure Overload ◽  
Aortic Aneurysms ◽  
Endoplasmic Reticulum Stress Response ◽  
Extracellular Matrix Protein ◽  
Ang Ii ◽  
Wild Type ◽  
Resistance Arteries ◽  
Thrombospondin 4

Thrombospondin-4 (TSP-4) is a multidomain calcium-binding protein that has both intracellular and extracellular functions. As an extracellular matrix protein, it is involved in remodeling processes. Previous work showed that, in the cardiovascular system, TSP-4 expression is induced in the heart in response to experimental pressure overload and infarction injury. Intracellularly, it mediates the endoplasmic reticulum stress response in the heart. In this study, we explored the role of TSP-4 in hypertension. For this purpose, wild-type and TSP-4 knockout ( Thbs4 −/−) mice were treated with angiotensin II (ANG II). Hearts from ANG II-treated Thbs4 −/− mice showed an exaggerated hypertrophic response. Interestingly, aortas from Thbs4 −/− mice treated with ANG II showed a high incidence of aneurysms. In resistance arteries, ANG II-treated wild-type mice showed impaired endothelial-dependent relaxation. This was not observed in ANG II-treated Thbs4 −/− mice or in untreated controls. No differences were found in the passive pressure-diameter curves or stress-strain relationships, although ANG II-treated Thbs4 −/− mice showed a tendency to be less stiff, associated with thicker diameters of the collagen fibers as revealed by electron microscopy. We conclude that TSP-4 plays a role in hypertension, affecting cardiac hypertrophy, aortic aneurysm formation, as well as endothelial-dependent relaxation in resistance arteries.

scholarly journals Direct observation of structure and dynamics during phase separation of an elastomeric protein

2017 ◽  
Vol 114 (22) ◽  
pp. E4408-E4415 ◽  
Author(s):  
Sean E. Reichheld ◽  
Lisa D. Muiznieks ◽  
Fred W. Keeley ◽  
Simon Sharpe
Keyword(s):  
Phase Separation ◽  
Matrix Protein ◽  
Molecular Mechanisms ◽  
Bulk Water ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Cross Linking ◽  
Structure And Dynamics ◽  
Chemical Cross Linking

Despite its growing importance in biology and in biomaterials development, liquid–liquid phase separation of proteins remains poorly understood. In particular, the molecular mechanisms underlying simple coacervation of proteins, such as the extracellular matrix protein elastin, have not been reported. Coacervation of the elastin monomer, tropoelastin, in response to heat and salt is a critical step in the assembly of elastic fibers in vivo, preceding chemical cross-linking. Elastin-like polypeptides (ELPs) derived from the tropoelastin sequence have been shown to undergo a similar phase separation, allowing formation of biomaterials that closely mimic the material properties of native elastin. We have used NMR spectroscopy to obtain site-specific structure and dynamics of a self-assembling elastin-like polypeptide along its entire self-assembly pathway, from monomer through coacervation and into a cross-linked elastic material. Our data reveal that elastin-like hydrophobic domains are composed of transient β-turns in a highly dynamic and disordered chain, and that this disorder is retained both after phase separation and in elastic materials. Cross-linking domains are also highly disordered in monomeric and coacervated ELP3 and form stable helices only after chemical cross-linking. Detailed structural analysis combined with dynamic measurements from NMR relaxation and diffusion data provides direct evidence for an entropy-driven mechanism of simple coacervation of a protein in which transient and nonspecific intermolecular hydrophobic contacts are formed by disordered chains, whereas bulk water and salt are excluded.

Abstract 15539: Single-cell Analysis of Aortic Tissues From Patients With Marfan Syndrome Reveals Changes in Smooth Muscle Cell Differentiation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Ashley Dawson ◽  
Yanming Li ◽  
Pingping Ren ◽  
Hernan Vasquez ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Single Cell ◽  
Marfan Syndrome ◽  
Immune Cells ◽  
Matrix Protein ◽  
Immune Cell ◽  
Aortic Aneurysms ◽  
Extracellular Matrix Protein ◽  
Cardiac Transplant ◽  
Control Tissue

Background: Thoracic aortic aneurysms associated with Marfan syndrome (MFS) carry a high risk of mortality; however, the molecular and cellular processes leading to aortopathy in this population remain poorly understood. We aimed to use single-cell RNA (scRNA) sequencing to define the non-immune cell populations present within the aortic wall in MFS, hypothesizing that these would differ from those of non-aneurysmal control tissue. Methods: We performed scRNA sequencing of ascending aortic aneurysm tissues from MFS patients (n=3) undergoing aneurysm repair and of age-matched, non-aneurysmal control tissue from cardiac transplant donors and recipients (n=4). The Seurat package in R was used for analysis. Differentially expressed genes were identified using edgeR. Results: Eighteen non-immune cell clusters were identified, with conserved gene expression of the largest of the clusters consistent with smooth muscle cells (SMCs; n=6), fibroblasts (n=3), and endothelial cells (n=3). The SMCs and fibroblasts exhibited graded changes in their expression of contractile and extracellular matrix protein genes, supportive of a phenotypic continuum. Additionally, we identified differences in the proportions of non-immune cells in MFS tissues compared to controls. In control tissues, the most common non-immune cells expressed markers of contractile SMC maturity including CNN1 , MYH11 , and SMTN . In contrast, the largest clusters in MFS tissue were most closely related to SMCs on correlation analysis, but displayed increased expression of cyclin genes as well as immune, endothelial, and fibroblast genes indicative of de-differentiated, proliferative SMCs. Additionally, expression of genes associated with SMC phenotypic maturity, including MYH11 and MYOCD , were significantly downregulated in several of the MFS SMC clusters. Conclusion: Our data demonstrate a phenotypic continuum between fibroblasts and SMCs, with aortas from patients with MFS exhibiting an increased proportion of de-differentiated, proliferative SMCs compared to controls. Additionally, markers of SMC maturity were downregulated in SMCs in MFS compared to controls. This may be due to disruption of signaling pathways that promote differentiation.

scholarly journals An Elastin-Derived Self-Assembling Polypeptide

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Antonietta Pepe ◽  
Brigida Bochicchio
Keyword(s):  
Elastic Properties ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Hydrophobic Region ◽  
Beta Turn ◽  
Self Assembling ◽  
Polypeptide Sequence ◽  
Hydrophilic Region ◽  
Self Aggregation

Elastin is an extracellular matrix protein responsible for the elastic properties of organs and tissues, the elastic properties being conferred to the protein by the presence of elastic fibers. In the perspective of producing tailor-made biomaterials of potential interest in nanotechnology and biotechnology fields, we report a study on an elastin-derived polypeptide. The choice of the polypeptide sequence encoded by exon 6 of Human Tropoelastin Gene is dictated by the peculiar sequence of the polypeptide. As a matter of fact, analogously to elastin, it is constituted of a hydrophobic region (GLGAFPAVTFPGALVPGG) and of a more hydrophilic region rich of lysine and alanine residues (VADAAAAYKAAKA). The role played by the two different regions in triggering the adoption of beta-turn and beta-sheet conformations is herein discussed and demonstrated to be crucial for the self-aggregation properties of the polypeptide.

Gene expression changes associated with fibronectin-induced cardiac myocyte hypertrophy

2004 ◽  
Vol 18 (3) ◽  
pp. 273-283 ◽  
Author(s):  
Hua Chen ◽  
Xueyin N. Huang ◽  
Alexandre F. R. Stewart ◽  
Jorge L. Sepulveda
Keyword(s):  
Gene Expression ◽  
Cardiac Myocytes ◽  
Matrix Protein ◽  
Cardiac Myocyte ◽  
Tissue Growth ◽  
In Vivo Studies ◽  
Extracellular Matrix Protein ◽  
Myocyte Hypertrophy ◽  
Cardiac Myocyte Hypertrophy

Fibronectin (FN) is an extracellular matrix protein that binds to integrin receptors and couples cardiac myocytes to the basal lamina. Cardiac FN expression is elevated in models of pressure overload, and FN causes cultured cardiac myocytes to hypertrophy by a mechanism that has not been characterized in detail. In this study, we analyzed the gene expression changes induced by FN in purified rat neonatal ventricular myocytes using the Affymetrix RAE230A microarray, to understand how FN affects gene expression in cardiac myocytes and to separate the effects contributed by cardiac nonmyocytes in vivo. Pathway analysis using z-score statistics and comparison with a mouse model of cardiac hypertrophy revealed several pathways stimulated by FN in cardiac myocytes. In addition to the known cardiac myocyte hypertrophy markers, FN significantly induced metabolic pathways including virtually all of the enzymes of cholesterol biosynthesis, fatty acid biosynthesis, and the mitochondrial electron transport chain. FN also increased the expression of genes coding for ribosomal proteins, translation factors, and the ubiquitin-proteasome pathway. Interestingly, cardiac myocytes plated on FN showed elevated expression of the fibrosis-promoting peptides connective tissue growth factor (CTGF), WNT1 inducible signaling pathway protein 2 (WISP2), and secreted acidic cysteine-rich glycoprotein (SPARC). Our data complement in vivo studies and reveal several novel genes and pathways stimulated by FN, pointing to cardiac myocyte-specific mechanisms that lead to development of the hypertrophic phenotype.

scholarly journals Protein Kinase C Alpha Acting Through Phorbol-12-Myristate 13-Acetate Regulates Nephronectin Gene Expression Via c-Jun and c-Fos Transcription Factors

2021 ◽  
Author(s):  
Mitsuhiro Kinoshita ◽  
Atsushi Yamada ◽  
Kiyohito Sasa ◽  
Kaori Ikezaki ◽  
Tatsuo Shirota ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Small Interfering Rna ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Down Regulation ◽  
Kinase C ◽  
Interfering Rna ◽  
Dose Dependent

Abstract Nephronectin (Npnt) is an extracellular matrix protein and ligand of integrin α8β1 known to promote differentiation of osteoblasts. A search for factors that regulate Npnt gene expression in osteoblasts revealed that phorbol 12-myristate 13-acetate (PMA), which activates protein kinase C (PKC), had a strong effect to suppress that expression. Research was then conducted to elucidate the signaling pathway responsible for regulation of Npnt gene expression by PMA in osteoblasts. Treatment of MC3T3-E1 cells with PMA suppressed cell differentiation and Npnt gene expression. Effects were noted at a low concentration of PMA, and were time- and dose-dependent. Furthermore, treatment with the PKC signal inhibitor Gö6983 inhibited down-regulation of Npnt expression, while transfection with small interfering RNA (siRNA) of PKCα, c-Jun, and c-Fos suppressed that down-regulation. The present results suggest regulation of Npnt gene expression via the PKCα and c-Jun/c-Fos pathway.

scholarly journals Decreased Levels of Microfibril-Associated Glycoprotein (MAGP)-1 in Patients with Colon Cancer and Obesity Are Associated with Changes in Extracellular Matrix Remodelling

2021 ◽  
Vol 22 (16) ◽  
pp. 8485
Author(s):  
Iranzu Gómez de Segura ◽  
Patricia Ahechu ◽  
Javier Gómez-Ambrosi ◽  
Amaia Rodríguez ◽  
Beatriz Ramírez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colon Cancer ◽  
Extracellular Matrix ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Mrna Levels ◽  
Expression Levels ◽  
The Impact ◽  
Ht 29 ◽  
Gene Expression Levels

Objective: The protein microfibril-associated glycoprotein (MAGP)-1 constitutes a crucial extracellular matrix protein. We aimed to determine its impact on visceral adipose tissue (VAT) remodelling during obesity-associated colon cancer (CC). Methods: Samples obtained from 79 subjects (29 normoponderal (NP) (17 with CC) and 50 patients with obesity (OB) (19 with CC)) were used in the study. Circulating concentrations of MAGP-1 and its gene expression levels (MFAP2) in VAT were analysed. The impact of inflammation-related factors and adipocyte-conditioned media (ACM) on MFAP2 mRNA levels in colon adenocarcinoma HT-29 cells were further analysed. The effects of MAGP-1 in the expression of genes involved in the extracellular matrix (ECM) remodelling and tumorigenesis in HT-29 cells was also explored. Results: Obesity (p < 0.01) and CC (p < 0.001) significantly decreased MFAP2 gene expression levels in VAT whereas an opposite trend in TGFB1 mRNA levels was observed. Increased mRNA levels of MFAP2 after the stimulation of HT-29 cells with lipopolysaccharide (LPS) (p < 0.01) and interleukin (IL)-4 (p < 0.01) together with a downregulation (p < 0.05) after hypoxia mimicked by CoCl2 treatment was observed. MAGP-1 treatment significantly enhanced the mRNA levels of the ECM-remodelling genes collagen type 6 α3 chain (COL6A3) (p < 0.05), decorin (DCN) (p < 0.01), osteopontin (SPP1) (p < 0.05) and TGFB1 (p < 0.05). Furthermore, MAGP-1 significantly reduced (p < 0.05) the gene expression levels of prostaglandin-endoperoxide synthase 2 (COX2/PTGS2), a key gene controlling cell proliferation, growth and adhesion in CC. Interestingly, a significant decrease (p < 0.01) in the mRNA levels of MFAP2 in HT-29 cells preincubated with ACM from volunteers with obesity compared with control media was observed. Conclusion: The decreased levels of MAGP-1 in patients with obesity and CC together with its capacity to modulate key genes involved in ECM remodelling and tumorigenesis suggest MAGP-1 as a link between AT excess and obesity-associated CC development.

Characterization of Cardiac Function and Arterial Mechanics During Early Postnatal Development in Fibulin-5 Null Mice

2013 ◽  
Author(s):  
Victoria Le ◽  
Hiromi Yanagisawa ◽  
Jessica Wagenseil
Keyword(s):  
Matrix Protein ◽  
Elastic Fiber ◽  
Connective Tissue Disorder ◽  
Fiber Formation ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Arterial Mechanics ◽  
Early Postnatal Development ◽  
Complex Process

Fibulin-5 is an extracellular matrix protein that interacts with other proteins during a complex process that results in elastic fiber formation from the elastin precursor, tropoelastin [1]. Elastic fibers are an important component of tissues requiring elasticity, including large arteries, lungs and skin. In mice lacking fibulin-5 ( Fbln5−/−), these tissues contain disorganized elastic fibers and exhibit decreased elasticity [2]. The phenotype of Fbln5−/− mice is similar to that of humans with cutis laxa, a connective tissue disorder characterized by loose skin and narrow arteries with reduced compliance.

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