Cartilage oligomeric matrix protein (thrombospondin-5) is expressed by human vascular smooth muscle cells

COMP promotes pancreatic fibrosis by activating pancreatic stellate cells through CD36-ERK/AKT signaling pathways

BACKGROUND

Pancreatic fibrosis is one of the most important pathological features of chronic pancreatitis (CP) and pancreatic stellate cells (PSCs) are the key cells of fibrosis. As an extracellular matrix (ECM) glycoprotein, cartilage oligomeric matrix protein (COMP) is critical for collagen assembly and ECM stability and recent studies showed that COMP exert promoting fibrosis effect in the skin, lungs and liver. However, the role of COMP in activation of PSCs and pancreatic fibrosis remain unclear. We aimed to investigate the role and specific mechanisms of COMP in regulating the profibrotic phenotype of PSCs and pancreatic fibrosis.

METHODS

ELISA method was used to determine serum COMP in patients with CP. Mice model of CP was established by repeated intraperitoneal injection of cerulein and pancreatic fibrosis was evaluated by Hematoxylin-Eosin staining (H&E) and Sirius red staining. Immunohistochemical staining was used to detect the expression changes of COMP and fibrosis marker such as α-SMA and Fibronectin in pancreatic tissue of mice. Cell Counting Kit-8, Wound Healing and Transwell assessed the proliferation and migration of human pancreatic stellate cells (HPSCs). Western blotting, qRT-PCR and immunofluorescence staining were performed to detect the expression of fibrosis marker, AKT and MAPK family proteins in HPSCs. RNA-seq omics analysis as well as small interfering RNA of COMP, recombinant human COMP (rCOMP), MEK inhibitors and PI3K inhibitors were used to study the effect and mechanism of COMP on activation of HPSCs.

RESULTS

ELISA showed that the expression of COMP significantly increased in the serum of CP patients. H&E and Sirius red staining analysis showed that there was a large amount of collagen deposition in the mice in the CP model group and high expression of COMP, α-SMA, Fibronectin and Vimentin were observed in fibrotic tissues. TGF-β1 stimulates the activation of HPSCs and increases the expression of COMP. Knockdown of COMP inhibited proliferation and migration of HPSCs. Further, RNA-seq omics analysis and validation experiments in vitro showed that rCOMP could significantly promote the proliferation and activation of HPSCs, which may be due to promoting the phosphorylation of ERK and AKT through membrane protein receptor CD36. rCOMP simultaneously increased the expression of α-SMA, Fibronectin and Collagen I in HPSCs.

CONCLUSION

In conclusion, this study showed that COMP was up-regulated in CP fibrotic tissues and COMP induced the activation, proliferation and migration of PSCs through the CD36-ERK/AKT signaling pathway. COMP may be a potential therapeutic candidate for the treatment of CP. Interfering with the expression of COMP or the communication between COMP and CD36 on PSCs may be the next direction for therapeutic research.

The molecular mechanism of thrombospondin family members in cardiovascular diseases

Cardiovascular diseases have been identified as vital factors in global morbidity and mortality in recent years. The available evidence suggests that various cytokines and pathological proteins participate in these complicated and changeable diseases. The thrombospondin (TSP) family is a series of conserved, multidomain calcium-binding glycoproteins that cause cell-matrix and cell-cell effects via interactions with other extracellular matrix components and cell surface receptors. The TSP family has five members that can be divided into two groups (Group A and Group B) based on their different structures. TSP-1, TSP-2, and TSP-4 are the most studied proteins. Among recent studies and findings, we investigated the functions of several family members, especially TSP-5. We review the basic concepts of TSPs and summarize the relevant molecular mechanisms and cell interactions in the cardiovascular system. Targeting TSPs in CVD and other diseases has a remarkable therapeutic benefit.

Joint biomarker response to mechanical stimuli in osteoarthritis - A scoping review

Objective

Arthritic cartilage is primed for mechanical damage. Joint biochemical markers (JBM) could provide insight into the impact of mechanical stimulation on joint tissue turnover in osteoarthritis (OA) of potential use in clinical OA research and practice. However, existing studies of the acute impact of physical activities (PA) on JBM often contain risks of substantial bias. The purpose of this scoping review was to critically review and discuss existing reports of acute joint tissue turnover as reflected in JBM in relation to PA in OA and propose considerations for future research.

Design

We searched PubMed, Embase, and Scopus and reference lists for original reports on the acute impact of PA on JBM in human OA. Identified studies were reviewed by two reviewers forming the basis for the discussion of methodology.

Results

Search in databases resulted in nine eligible papers after full-text evaluation. Two additional papers were identified through reference lists, resulting in 11 papers included in this review. Ten investigated knee OA and one investigated hand OA. Biomarkers described were related to turnover of type II collagen, aggrecan, and cartilage oligomeric matrix protein.

Conclusions

The literature is dominated by small, simplistic studies, but suggests that mechanical stimulation can induce acute changes in joint biomarkers. In order to diminish the existing bias in future studies, it is important to recognize methodological considerations e.g. patient and biomarker selection as well as peri-interventional control. Common potential sources of bias include the acute shift in plasma volume due to cardiovascular stress and postural changes.

Cardiovascular disease risk in early rheumatoid arthritis: the impact of cartilage oligomeric matrix protein (COMP) and disease activity

BACKGROUND

To investigate whether baseline serum cartilage oligomeric matrix protein (COMP), patient characteristics, traditional cardiovascular disease (CVD) risk factors and disease activity over time predict CVD, in early rheumatoid arthritis (RA).

METHODS

This study included patients with early RA (< 12 months disease duration) (n = 233) recruited 1995-2005. Potential predictors of CVD and coronary artery disease (CAD) were assessed using Cox regression.

RESULTS

A first ever diagnosis of CVD occurred in 70 patients, and CAD in 52. Age, sex, hypertension and diabetes predicted CVD and CAD. COMP was associated with increased risk of CVD and CAD [crude hazard ratios (HRs) per SD 1.45; 95% CI 1.17-1.80 and 1.51; 95% CI 1.18-1.92, respectively]. When adjusted for age, sex, hypertension, diabetes and ESR, results where similar but did not reach significance [HRs 1.32, 95% CI 0.99-1.74 and 1.35, 95% CI 0.99-1.86]. Baseline disease activity did not independently predict CVD. High DAS28 (> 5.1) at two years was associated with increased risk of subsequent CVD [adjusted HR 2.58; 95% CI 1.10-6.04] and CAD. ESR and CRP at two years as well as cumulative disease activity over 2 years independently predicted CVD and CAD.

CONCLUSION

COMP may be a novel predictor of CVD and CAD in RA. Active disease two years after RA diagnosis, as well as cumulative disease activity, was associated with increased risk of CVD and CAD, independent of traditional CVD risk factors. Awareness of the particularly increased CVD risk among difficult to treat patients is important in order to further reduce CVD in RA.

Matricellular proteins in atherosclerosis development

The extracellular matrix (ECM) is an intricate network composed of various multi-domain macromolecules like collagen, proteoglycans, and fibronectin, etc., that form a structurally stable composite, contributing to the mechanical properties of tissue. However, matricellular proteins are non-structural, secretory extracellular matrix proteins, which modulate various cellular functions via interacting with cell surface receptors, proteases, hormones, and cell-matrix. They play essential roles in maintaining tissue homeostasis by regulating cell differentiation, proliferation, adhesion, migration, and several signal transduction pathways. Matricellular proteins display a broad functionality regulated by their multiple structural domains and their ability to interact with different extracellular substrates and/or cell surface receptors. The expression of these proteins is low in adults, however, gets upregulated following injuries, inflammation, and during tumor growth. The marked elevation in the expression of these proteins during atherosclerosis suggests a positive association between their expression and atherosclerotic lesion formation. The role of matricellular proteins in atherosclerosis development has remained an area of research interest in the last two decades and studies revealed these proteins as important players in governing vascular function, remodelling, and plaque formation. Despite extensive research, many aspects of the matrix protein biology in atherosclerosis are still unknown and future studies are required to investigate whether targeting pathways stimulated by these proteins represent viable therapeutic approaches for patients with atherosclerotic vascular diseases. This review summarizes the characteristics of distinct matricellular proteins, discusses the available literature on the involvement of matrix proteins in the pathogenesis of atherosclerosis and suggests new avenues for future research.

The rs3825807 Polymorphism of ADAMTS7 as a Potential Genetic Marker for Myocardial Infarction in Slovenian Subjects with Type 2 Diabetes Mellitus

BACKGROUND

A disintegrin and metalloprotease with thrombospondin motif 7 (ADAMTS-7) was reported to play a role in the migration of vascular smooth muscle cells and neointimal formation. The object of the study was to investigate the association between the rs3825807 polymorphism of ADAMTS7 and myocardial infarction among patients with type 2 diabetes mellitus in a Slovenian cohort.

METHODS

1590 Slovenian patients with type 2 diabetes mellitus were enrolled in this retrospective cross-sectional case-control study. In total, 463 had a history of recent myocardial infarction, and 1127 of the subjects in the control group had no clinical signs of coronary artery disease. Genetic analysis of an rs3825807 polymorphism of ADAMTS7 was performed with logistic regression.

RESULTS

Patients with the AA genotype had a higher prevalence of myocardial infarction than those in the control group in recessive [odds ratio (OR) 1.647; confidence interval (CI) 1.120-2.407; p = 0.011] and co-dominant (OR 2.153; CI 1.215-3.968; p = 0.011) genetic models.

CONCLUSION

We found a statistically significant association between rs3825807 and myocardial infarction in a cohort of Slovenian patients with type 2 diabetes mellitus. We report that the AA genotype might be a genetic risk factor for myocardial infarction.

EMILIN1 deficiency causes arterial tortuosity with osteopenia and connects impaired elastogenesis with defective collagen fibrillogenesis

EMILIN1 (elastin-microfibril-interface-located-protein-1) is a structural component of the elastic fiber network and localizes to the interface between the fibrillin microfibril scaffold and the elastin core. How EMILIN1 contributes to connective tissue integrity is not fully understood. Here, we report bi-allelic EMILIN1 loss-of-function variants causative for an entity combining cutis laxa, arterial tortuosity, aneurysm formation, and bone fragility, resembling autosomal-recessive cutis laxa type 1B, due to EFEMP2 (FBLN4) deficiency. In both humans and mice, absence of EMILIN1 impairs EFEMP2 extracellular matrix deposition and LOX activity resulting in impaired elastogenesis, reduced collagen crosslinking, and aberrant growth factor signaling. Collagen fiber ultrastructure and histopathology in EMILIN1- or EFEMP2-deficient skin and aorta corroborate these findings and murine Emilin1^-/- femora show abnormal trabecular bone formation and strength. Altogether, EMILIN1 connects elastic fiber network with collagen fibril formation, relevant for both bone and vascular tissue homeostasis.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.

Structure, evolution and expression of zebrafish cartilage oligomeric matrix protein (COMP, TSP5). CRISPR-Cas mutants show a dominant phenotype in myosepta

COMP (Cartilage Oligomeric Matrix Protein), also named thrombospondin-5, is a member of the thrombospondin family of extracellular matrix proteins. It is of clinical relevance, as in humans mutations in COMP lead to chondrodysplasias. The gene encoding zebrafish Comp is located on chromosome 11 in synteny with its mammalian orthologs. Zebrafish Comp has a domain structure identical to that of tetrapod COMP and shares 74% sequence similarity with murine COMP. Zebrafish comp is expressed from 5 hours post fertilization (hpf) on, while the protein is first detectable in somites of 11 hpf embryos. During development and in adults comp is strongly expressed in myosepta, craniofacial tendon and ligaments, around ribs and vertebra, but not in its name-giving tissue cartilage. As in mammals, zebrafish Comp forms pentamers. It is easily extracted from 5 days post fertilization (dpf) whole zebrafish. The lack of Comp expression in zebrafish cartilage implies that its cartilage function evolved recently in tetrapods. The expression in tendon and myosepta may indicate a more fundamental function, as in evolutionary distant Drosophila muscle-specific adhesion to tendon cells requires thrombospondin. A sequence encoding a calcium binding motif within the first TSP type-3 repeat of zebrafish Comp was targeted by CRISPR-Cas. The heterozygous and homozygous mutant Comp zebrafish displayed a patchy irregular Comp staining in 3 dpf myosepta, indicating a dominant phenotype. Electron microscopy revealed that the endoplasmic reticulum of myosepta fibroblasts is not affected in homozygous fish. The disorganized extracellular matrix may indicate that this mutation rather interferes with extracellular matrix assembly, similar to what is seen in a subgroup of chondrodysplasia patients. The early expression and easy detection of mutant Comp in zebrafish points to the potential of using the zebrafish model for large scale screening of small molecules that can improve secretion or function of disease-associated COMP mutants.

ADAMTS Proteins and Vascular Remodeling in Aortic Aneurysms

Extracellular matrix (ECM) in the vascular wall is a highly dynamic structure composed of a set of different molecules such as elastins, collagens, fibronectin (Fn), laminins, proteoglycans, and polysaccharides. ECM undergoes remodeling processes to regulate vascular smooth muscle and endothelial cells' proliferation, differentiation, and adhesion. Abnormalities affecting the ECM can lead to alteration in cellular behavior and from this, this can conduce to the development of pathologies. Metalloproteases play a key role in maintaining the homeostasis of ECM by mediating the cleavage of different ECM components. There are different types of metalloproteases: matrix metalloproteinases (MMPs), disintegrin and metalloproteinases (ADAMs), and ADAMs with thrombospondin motifs (ADAMTSs). ADAMTSs have been found to participate in cardiovascular physiology and diseases and specifically in aortic aneurysms. This review aims to decipher the potential role of ADAMTS proteins in the physiopathologic development of Thoracic Aortic Aneurysms (TAA) and Abdominal Aortic Aneurysms (AAA). This review will focus on what is known on the ADAMTS family involved in human aneurysms from human tissues to mouse models. The recent findings on THSD4 (encoding ADAMTSL6) mutations in TAA give a new insight on the involvement of the ADAMTS family in TAA.

Basic Components of Connective Tissues and Extracellular Matrix: Fibronectin, Fibrinogen, Laminin, Elastin, Fibrillins, Fibulins, Matrilins, Tenascins and Thrombospondins

Collagens are the most abundant components of the extracellular matrix (ECM) and many types of soft tissues. Elastin is another major component of certain soft tissues, such as arterial walls and ligaments. It is an insoluble polymer of the monomeric soluble precursor tropoelastin, and the main component of elastic fibers in matrix tissue where it provides elastic recoil and resilience to a variety of connective tissues, e.g., aorta and ligaments. Elastic fibers regulate activity of transforming growth factors β (TGFβ) through their association with fibrillin microfibrils. Elastin also plays a role in cell adhesion, cell migration, and has the ability to participate in cell signaling. Mutations in the elastin gene lead to cutis laxa. Many other molecules, though lower in quantity, function as essential, structural and/or functional components of the extracellular matrix in soft tissues. Some of these are reviewed in this chapter. Besides their basic structure, biochemistry and physiology, their roles in disorders of soft tissues are discussed only briefly as most chapters in this volume deal with relevant individual compounds. Fibronectin with its multidomain structure plays a role of "master organizer" in matrix assembly as it forms a bridge between cell surface receptors, e.g., integrins, and compounds such collagen, proteoglycans and other focal adhesion molecules. It also plays an essential role in the assembly of fibrillin-1 into a structured network. Though the primary role of fibrinogen is in clot formation, after conversion to fibrin by thrombin it also binds to a variety of compounds, particularly to various growth factors, and as such, fibrinogen is a player in cardiovascular and extracellular matrix physiology. Laminins contribute to the structure of the ECM and modulate cellular functions such as adhesion, differentiation, migration, stability of phenotype, and resistance towards apoptosis. Fibrillins represent the predominant core of microfibrils in elastic as well as non-elastic extracellular matrixes, and interact closely with tropoelastin and integrins. Not only do microfibrils provide structural integrity of specific organ systems, but they also provide basis for elastogenesis in elastic tissues. Fibrillin is important for the assembly of elastin into elastic fibers. Mutations in the fibrillin-1 gene are closely associated with Marfan syndrome. Latent TGFβ binding proteins (LTBPs) are included here as their structure is similar to fibrillins. Several categories of ECM components described after fibrillins are sub-classified as matricellular proteins, i.e., they are secreted into ECM, but do not provide structure. Rather they interact with cell membrane receptors, collagens, proteases, hormones and growth factors, communicating and directing cell-ECM traffic. Fibulins are tightly connected with basement membranes, elastic fibers and other components of extracellular matrix and participate in formation of elastic fibers. Matrilins have been emerging as a new group of supporting actors, and their role in connective tissue physiology and pathophysiology has not been fully characterized. Tenascins are ECM polymorphic glycoproteins found in many connective tissues in the body. Their expression is regulated by mechanical stress both during development and in adulthood. Tenascins mediate both inflammatory and fibrotic processes to enable effective tissue repair and play roles in pathogenesis of Ehlers-Danlos, heart disease, and regeneration and recovery of musculo-tendinous tissue. One of the roles of thrombospondin 1 is activation of TGFβ. Increased expression of thrombospondin and TGFβ activity was observed in fibrotic skin disorders such as keloids and scleroderma. Cartilage oligomeric matrix protein (COMP) or thrombospondin-5 is primarily present in the cartilage. High levels of COMP are present in fibrotic scars and systemic sclerosis of the skin, and in tendon, especially with physical activity, loading and post-injury. It plays a role in vascular wall remodeling and has been found in atherosclerotic plaques as well.

High Levels of Expression of Cartilage Oligomeric Matrix Protein in Lymph Node Metastases in Breast Cancer Are Associated with Reduced Survival

Simple Summary

Cartilage oligomeric matrix protein (COMP) is an emerging independent prognostic marker for breast cancer patients. COMP expression by cancer cells affects their metabolism, metastases, and the abundance of cancer stem cell populations. This study assessed the levels of COMP in the sera of metastatic breast cancer patients. Further, matched tumor tissues from the primary tumor and metastases were stained for COMP expression with immunohistochemistry. The levels of serum COMP were highest in the blood of metastatic ER-positive and HER2-positive patients. The expression of COMP in primary tumors correlated with COMP expression in the metastatic loci. Lymph node metastases (LNM) with COMP expression were associated with reduced survival. The expression of COMP in LNM at the time of primary diagnosis could indicate later development of visceral and lung metastases.

Abstract

Cartilage oligomeric matrix protein (COMP) is a regulator of the extracellular matrix and is expressed primarily in the cartilage. Recently, COMP expression was also documented in breast cancer patients both in sera and tumor biopsies, in both of which it could serve as an independent prognostic marker. This study aimed to assess COMP as a potential biomarker in the group of metastatic breast cancer patients. Levels of COMP were measured by ELISA in serum samples of 141 metastatic breast cancer patients. Biopsies from primary tumors, synchronous lymph node metastases, and distant metastases were stained for COMP expression. The levels of serum COMP were higher in patients with ER- and HER2-positive tumors when compared to triple-negative tumors and correlated with the presence of bone and lung metastases, circulating tumor cell count, and clusters. Most of the primary tumors expressing COMP (70%) retained the expression also in the lymph node metastases, which correlated with visceral metastases and reduced survival. In conclusion, COMP appears as a valuable biomarker in metastatic breast cancer patients indicating a more severe stage of the disease. Serum COMP levels were associated with specific types of metastases in patients with metastatic breast cancer emphasizing that further studies are warranted to elucidate its potential role as a monitoring marker.

In the balance: how do thrombospondins contribute to the cellular pathophysiology of cardiovascular disease?

Thrombospondins (TSPs) are multidomain, secreted proteins that associate with cell surfaces and extracellular matrix. In mammals, there is a large body of data on functional roles of various TSP family members in cardiovascular disease (CVD), including stroke, cardiac remodeling and fibrosis, atherosclerosis, and aortic aneurysms. Coding single nucleotide polymorphisms (SNPs) of TSP1 or TSP4 are also associated with increased risk of several forms of CVD. Whereas interactions and functional effects of TSPs on a variety of cell types have been studied extensively, the molecular and cellular basis for the differential effects of the SNPs remains under investigation. Here, we provide an integrative review on TSPs, their roles in CVD and cardiovascular cell physiology, and known properties and mechanisms of TSP SNPs relevant to CVD. In considering recent expansions to knowledge of the fundamental cellular roles and mechanisms of TSPs, as well as the effects of wild-type and variant TSPs on cells of the cardiovascular system, we aim to highlight knowledge gaps and areas for future research or of translational potential.

The role of caveolae in endothelial dysfunction

Caveolae, the specialized cell-surface plasma membrane invaginations which are abundant in endothelial cells, play critical roles in regulating various cellular processes, including cholesterol homeostasis, nitric oxide production, and signal transduction. Endothelial caveolae serve as a membrane platform for compartmentalization, modulation, and integration of signal events associated with endothelial nitric oxide synthase, ATP synthase β, and integrins, which are involved in the regulation of endothelial dysfunction and related cardiovascular diseases, such as atherosclerosis and hypertension. Furthermore, these dynamic microdomains on cell membrane are modulated by various extracellular stimuli, including cholesterol and flow shear stress. In this brief review, we summarize the critical roles of caveolae in the orchestration of endothelial function based on recent findings as well as our work over the past two decades.

Does moderate intensity impact exercise and non-impact exercise induce acute changes in collagen biochemical markers related to osteoarthritis? - An exploratory randomized cross-over trial

OBJECTIVE

To investigate acute changes in biochemical markers of cartilage turnover in response to moderate intensity exercise with and without joint impact in humans with knee osteoarthritis.

DESIGN

We conducted a randomized, cross-over, exploratory clinical study. Twenty subjects with knee osteoarthritis (OA) were randomized, of which twenty completed 30 min of cycling and 15 completed 30 min of running on days 1 week apart. Fasting blood samples were taken before, immediately after and 1, 2, 3, and 24 h after activity was initiated. Midstream spot urine was sampled before and after activity. Serum samples were analyzed for concentrations of fragment of type II collagen degradation, C2M, fragment of type VI collagen degradation, C6M, cartilage oligomeric matrix protein, COMP, marker of type II collagen formation, PRO-C2, and urine for marker of crosslinked type II collagen degradation, CTX-II. To establish a reference, all subjects had similar samples taken during rest on a separate day. Data was analyzed in a restricted maximum likelihood based random effects linear mixed model.

RESULTS

C2M trended to increase after cycling compared running (13.49%, 95%CI: -0.36-27.34%) and resting (12.88%, 95%CI: 0.2-25.6%) and the type II collagen formation/degradation ratio switched towards degradation after cycling, but not running. C6M trended to decrease after cycling (-8.1%, 95%CI: -14.8 to -1.4%) and running (-6.8%, 95%CI: -14.16-0.55%).

CONCLUSION

In persons with knee OA moderate intensity exercise without joint impact may induce acute changes in circulating levels of biochemical markers reflecting type II and VI collagen degradation.

Coronary Disease Association With ADAMTS7 Is Due to Protease Activity

[Figure: see text].

Correlation between serum cartilage oligomeric matrix protein and major adverse cardiovascular events within 30 days in patients with acute coronary syndrome

Background

We studied the correlation between cartilage oligomeric matrix protein (COMP) and major adverse cardiovascular events in patients with acute coronary syndrome (ACS) within 30 days.

Methods

This study included 170 ACS patients who were hospitalized in the Second Affiliated Hospital of Nantong University from August 2017 to April 2019. Serum COMP level was measured at baseline. The enrolled patients were followed up for 30 days and grouped according to the occurrence of major adverse cardiovascular events (MACE) during follow-up. Among the 170 patients, 23 patients had MACE during hospitalization (MACE group), and 147 patients had no MACE (no MACE group).

Results

The serum COMP levels in the MACE group were significantly higher than those of the non-MACE group [84.85 (51.55, 141.75) vs. 20.65 (9.11, 46.31) ng/mL, respectively, P<0.05]. The area under the receiver operating characteristic (ROC) curve for COMP in predicting the occurrence of MACE within 30 days was 0.839, with a cutoff level of 39.9 ng/mL [95% confidence interval (CI): 0.774–0.890], 86.96% sensitivity, and 72.79% specificity (P<0.0001). Multivariate logistic regression analysis showed that serum COMP could be used as an independent predictor of MACE within 30 days in ACS patients [odds ratio (OR): 1.024, 95% CI: 1.0133–1.0349, P=0.0001].

Conclusions

Serum COMP is associated with the short-term prognosis of ACS patients. High serum COMP levels can be used as a predictor of MACE within 30 days in ACS patients.

COMP (Cartilage Oligomeric Matrix Protein) Neoepitope: A Novel Biomarker to Identify Symptomatic Carotid Stenosis

OBJECTIVE

COMP (cartilage oligomeric matrix protein) is abundantly expressed in the cardiovascular system, cartilage, and atherosclerotic plaques. We investigated if the total COMP (COMPtotal) and COMP neoepitope (COMPneo) with other cardiovascular markers and clinical parameters could identify symptomatic carotid stenosis. Approach and Results: Blood samples were collected from patients with symptomatic carotid stenosis (stenosis, n=50), patients with stroke without carotid stenosis but small plaques (plaque, n=50), and control subjects (n=50). COMPtotal and COMPneo were measured using an ELISA. Ninety-two cardiovascular disease markers were measured by the Olink CVD kit. The presence of native COMP and COMPneo was determined by immunohistochemistry. The concentration of COMPneo was higher and COMPtotal was lower in the stenosis group. When the concentration was compared between the stenosis and control groups, IL-1ra (interleukin-1 receptor antagonist protein), IL6 (interleukin-6), REN (Renin), MMP1 (matrix metalloproteinase-1), TRAIL-R2 (tumor necrosis factor-related apoptosis-inducing ligand receptor 2), ITGB1BP2 (integrin beta 1 binding protein 2), and COMPneo were predictive of stenosis. Conversely, KLK6 (kallikrein-6), COMPtotal, NEMO (nuclear factor-kappa-B essential modulator), SRC (Proto-oncogene tyrosine-protein kinase Src), SIRT2 (SIR2-like protein), CD40 (cluster of differentiation 40), TF (tissue factor), MP (myoglobin), and RAGE (receptor for advanced glycation end-products) were predictive of the control group. Model reproducibility was good with the receiver operating characteristic plot area under the curve being 0.86. When comparing the plaque group and stenosis group, COMPneo, GAL (galanin), and PTX3 (pentraxin-related protein PTX3) were predictive of stenosis. Model reproducibility was excellent (receiver operating characteristic plot area under the curve 0.92). COMPneo was detected in smooth muscle-, endothelial-, and foam-cells in carotid stenosis.

CONCLUSIONS

Degradation of COMP may be associated with atherosclerosis progression and generation of a specific COMP fragment-COMPneo. This may represent a novel biomarker that together with COMPtotal and other risk-markers could be used to identify symptomatic carotid stenosis. Graphic Abstract: A graphic abstract is available for this article.

Cartilage oligomeric matrix protein fine-tunes disturbed flow-induced endothelial activation and atherogenesis

Disturbed flow leads to increased inflammatory responses of endothelial cells (ECs) prone to atherogenic state. Currently, little is known about the physiological mechanisms protecting vasculature against disturbed flow-activated ECs leading to atherosclerosis. Understanding the protective mediators involved in EC activation could provide novel therapeutic strategies for atherosclerosis. The extracellular matrix microenvironment profoundly regulates cellular homeostasis. A non-EC resident ECM protein, cartilage oligomeric matrix protein (COMP), has diverse protective roles in the cardiovascular system. To determine whether COMP could protect against disturbed flow-activated EC and atherosclerosis, we compared oscillatory shear stress (OSS) induced EC activation coated with various ECM proteins. Purified COMP inhibited EC activation caused by OSS. EC activation was upregulated in the aortic arch where the flow is disturbed in COMP^-/- mice as compared with wild-type mice under physiological conditions or pathologically in partially ligated mouse carotid arteries. Mechanistically, co-immunoprecipitation, mammalian two-hybrid and FRET assay results suggest that COMP bound directly to integrin α5 via its C-terminus. We next synthesized a COMP-derived peptidomimetics (CCPep24) mimicking a specific COMP-integrin α5 interaction and found that CCPep24 protected against EC activation and atherogenesis in vivo. This study extends our current understanding of how ECM and flow coordinately fine-tune EC homeostasis and reveals the potential therapeutic effect of COMP or COMP-derived peptidomimetics on blocking aberrant integrin α5 activation, inflammatory EC activation and atherosclerosis pathogenesis.

Thrombospondin-5 and fluvastatin promote angiogenesis and are protective against endothelial cell apoptosis

The thrombospondins (TSPs), multifunctional matricellular proteins, are known mediators of endothelial cell (EC) angiogenesis and apoptosis. TSP-1, an antiangiogenic molecule, is important in the progression of vascular disease, in part by inducing EC apoptosis. TSP-2, although less studied, also induces EC apoptosis and inhibits angiogenesis. The effects of TSP-5 are largely unexplored in ECs, but TSP-5 is believed to be protective against arterial disease. Statin drugs have been shown to have beneficial pleiotropic effects, including decreasing EC apoptosis, increasing angiogenesis, and blocking TSP signaling. We hypothesized TSP-5 will be proangiogenic and antiapoptotic, and statin pretreatment would reverse the proapoptotic and antiangiogenic phenotype of TSP-1 and TSP-2. ECs were exposed to serum-free medium, TSP-1, TSP-2, or TSP-5 with or without fluvastatin pretreatment. Quantitative real-time polymerase chain reaction was performed on 96 apoptosis and 96 angiogenesis-related genes using microfluidic card assays. Angiogenesis was measured using Matrigel assays, while apoptosis was measured by fluorescent caspase assay. TSP-5 suppressed apoptotic genes and had a mixed effect on the angiogenic genes; however, TSP-5 did not alter apoptois but was proangiogenic. Pretreatment with fluvastatin downregulated proapoptotic genes and apoptosis and upregulated proangiogenic genes and angiogenesis. Findings indicate TSP-5 and fluvastatin have a protective effect on ECs, being proangiogenic and reversing the antiangiogenic effects of TSP-1 and TSP-2. In conclusion, TSP-5 and fluvastatin may be beneficial for inducing angiogenesis in the setting of ischemia.

Chondrodysplasias and Aneurysmal Thoracic Aortopathy: An Emerging Tale of Molecular Intersection

Although at first glance chondrodysplasia and aneurysmal thoracic aortopathy seem oddly dissimilar, recent lines of evidences indicate that they share molecular similarities. Chondrodysplasias are a group of skeletal disorders characterized by genetic defects in hyaline cartilage. Aneurysmal thoracic aortopathy is the pathological enlargement of the thoracic aorta due to wall weakness, along with its ensuing life-threatening complications (i.e., aortic dissection and/or rupture). Extracellular matrix dysregulation, abnormal TGF-β signaling, and, to a more limited extent, endoplasmic reticulum stress emerge as common disease processes. In this review we provide a comprehensive overview of the genetic and pathomechanistic overlap as well as of how these commonalities can guide treatment strategies for both disease entities.

Elevated serum cartilage oligomeric matrix protein and the metalloproteinase-ADAMTS7 levels are associated with vascular calcification in maintenance hemodialysis patients

BACKGROUND

Vascular calcification is common in maintenance hemodialysis (HD) patients. Recent studies showed that cartilage oligomeric matrix protein (COMP) could protect blood vessels from calcification, but the role of ADAMTS7 was opposite. We aimed to investigate the relationship between serum COMP, ADAMTS7 levels and vascular calcification scores in HD patients.

METHODS

Serum COMP and ADAMTS7 levels were tested by ELISA and we compared calcification scores between high and low COMP groups, also between high and low ADAMTS7 groups. We also investigated the differences of serum COMP and ADAMTS7 levels between mild and severe vascular calcification groups. The relationship between serum COMP and ADAMTS7 levels was analyzed in the end.

RESULTS

Serum COMP and ADAMTS7 levels were both higher in HD patients than in control (29.63 vs 14.23 ng/mL, P = .002, 11.12 vs 2.40 ng/mL, P = .005). Serum COMP levels in severe vascular calcification (VC) group were higher than in mild VC (43.13 ± 28.77 vs 26.75 ± 18.22 ng/mL, P = .010). Serum ADAMTS7 levels were positively correlated with radial and digital arteries (small arteries) calcification scores (r = .249, P = .033). And serum COMP and ADAMTS7 levels were positively correlated (r = .348, P = .026).

CONCLUSIONS

Serum COMP and ADAMTS7 levels were probably associated with vascular calcification scores in HD respectively.

Metabolic Stress

Mitochondria regulate major aspects of cell function by producing ATP, contributing to Ca²⁺ signaling, influencing redox potential, and controlling levels of reactive oxygen species. In this review, we will discuss recent findings that illustrate how mitochondrial respiration, Ca²⁺ handling, and production of reactive oxygen species affect vascular smooth muscle cell function during neointima formation. We will review mitochondrial fission/fusion as fundamental mechanisms for smooth muscle proliferation, migration, and metabolism and examine the role of mitochondrial mobility in cell migration. In addition, we will summarize novel aspects by which mitochondria regulate apoptosis.

Fibroblastic Reticular Cells Control Conduit Matrix Deposition during Lymph Node Expansion

Lymph nodes (LNs) act as filters, constantly sampling peripheral cues. This is facilitated by the conduit network, a tubular structure of aligned extracellular matrix (ECM) fibrils ensheathed by fibroblastic reticular cells (FRCs). LNs undergo rapid 3- to 5-fold expansion during adaptive immune responses, but these ECM-rich structures are not permanently damaged. Whether conduit flow or filtering function is affected during LN expansion is unknown. Here, we show that conduits are partially disrupted during acute LN expansion, but FRC-FRC contacts remain connected. We reveal that polarized FRCs deposit ECM basolaterally using LL5-β and that ECM production is regulated at transcriptional and secretory levels by the C-type lectin CLEC-2, expressed by dendritic cells. Inflamed LNs maintain conduit size exclusion, and flow is disrupted but persists, indicating the robustness of this structure despite rapid tissue expansion. We show how dynamic communication between peripheral tissues and LNs provides a mechanism to prevent inflammation-induced fibrosis in lymphoid tissue.

Upregulation of ADAMTS‑7 and downregulation of COMP are associated with spontaneous abortion

A disintegrin and metalloproteinase with thrombospondin motifs 7 (ADAMTS-7) has been revealed to serve an important role in inflammation-associated diseases. However, the role of ADAMTS-7 in spontaneous abortion (SA) remains unclear. In the present study, human and mouse decidual tissues were used to detect the expression of ADAMTS-7 and cartilage oligomeric matrix protein (COMP) in mice with lipopolysaccharide (LPS)-induced abortion (10 mice/group), and in SA humans and the corresponding control group (21 participants in the SA group and 15 participants in the control group). The results revealed that ADAMTS-7 expression was upregulated and that COMP expression was downregulated in the mouse decidual tissue of the LPS-induced abortion group, when compared with that of the normal control group. The results were further confirmed by western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, which revealed increased ADAMTS-7 and decreased COMP expression at the protein and mRNA levels in mice treated with LPS. Additionally, the expression of ADAMTS-7 was negatively correlated with the expression of COMP in mice, with a correlation coefficient of −0.936 (P<0.001). In addition, the expression of ADAMTS-7 and COMP exhibited was similar in the decidual tissue of SA patients when compared with the levels observed in the tissues of the normal control participants, as demonstrated by increased ADAMTS-7 expression and decreased COMP expression. Western blotting and RT-qPCR analysis revealed that ADAMTS-7 was increased and COMP was decreased in the decidual tissue of SA subjects. The correlation analysis of ADAMTS-7 and COMP in human decidual tissue also revealed a similar result, with a correlation coefficient of −0.836 (P<0.001). The results of the present study demonstrated that ADAMTS-7 was upregulated and COMP was downregulated in the decidual tissues of humans and mice with SA, and a negative correlation was identified between the expression levels of ADAMTS-7 and COMP, thereby providing novel evidence for a better understanding of the pathogenesis of SA, which may lead to improvements in the clinical pregnancy outcomes of these individuals.

Cartilage oligomeric matrix protein: COMPopathies and beyond

Cartilage oligomeric matrix protein (COMP) is a large pentameric glycoprotein that interacts with multiple extracellular matrix proteins in cartilage and other tissues. While, COMP is known to play a role in collagen secretion and fibrillogenesis, chondrocyte proliferation and mechanical strength of tendons, the complete range of COMP functions remains to be defined. COMPopathies describe pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), two skeletal dysplasias caused by autosomal dominant COMP mutations. The majority of the mutations are in the calcium binding domains and compromise protein folding. COMPopathies are ER storage disorders in which the retention of COMP in the chondrocyte ER stimulates overwhelming cellular stress. The retention causes oxidative and inflammation processes leading to chondrocyte death and loss of long bone growth. In contrast, dysregulation of wild-type COMP expression is found in numerous diseases including: fibrosis, cardiomyopathy and breast and prostate cancers. The most exciting clinical application is the use of COMP as a biomarker for idiopathic pulmonary fibrosis and cartilage degeneration associated osteoarthritis and rheumatoid and, as a prognostic marker for joint injury. The ever expanding roles of COMP in single gene disorders and multifactorial diseases will lead to a better understanding of its functions in ECM and tissue homeostasis towards the goal of developing new therapeutic avenues.

Changes in synovial fluid and serum concentrations of cartilage oligomeric matrix protein over 5 years after anterior cruciate ligament rupture: an exploratory analysis in the KANON trial

OBJECTIVE

To monitor longitudinal changes of cartilage oligomeric matrix protein (COMP) in synovial fluid (sf) and serum (s) over 5 years after acute anterior cruciate ligament (ACL) rupture, and to compare results from two commercial COMP immunoassays.

DESIGN

Bio-fluids were collected from 121 patients on six occasions over 5 years after acute ACL injury, and from 25 knee healthy reference subjects. Concentrations of sf- and sCOMP were measured by AnaMar (sCOMP-Ana) and by BioVendor (sf- and sCOMP-Bio) immunoassays; other biomarkers were previously assessed. We used ANCOVA for group comparisons and linear mixed models for associations between biomarkers over 5-years with P < 0.05 considered a statistically significant difference or association.

RESULTS

Compared to the reference group, sfCOMP-Bio concentrations were 2-fold elevated within 6 weeks after ACL injury and remained elevated 5 years thereafter, whereas sCOMP-Bio and sCOMP-Ana concentrations were no different from reference levels at any time point. Over the 5-year period, there was an association between sCOMP-Bio and sCOMP-Ana concentrations, although neither sCOMP-Bio nor sCOMP-Ana associated with sfCOMP-Bio. sfCOMP-Bio associated with SF ARGS-aggrecan, urine type I and II collagens (uNTX-I and uCTX-II) and SF cytokines, while sCOMP-Bio associated inversely with uCTX-II, uNTX-I and SF cytokines.

CONCLUSION

The local process after an acute ACL injury generates increased SF COMP concentrations in the injured knee up to 5 years after injury. This response is not detected in serum. Discrepancies in associations between sCOMP measured by BioVendor and AnaMar immunoassays with other biomarkers indicate differences in detected COMP fragments.

Cartilage oligomeric matrix protein is differentially expressed in human subcutaneous adipose tissue and regulates adipogenesis

Objective

The composition of the extracellular matrix (ECM) impacts adipocyte function and might determine adipose tissue (AT) function and distribution. Cartilage oligomeric matrix protein (COMP), a matricellular protein usually studied in bone and cartilage, is highly differentially expressed between subcutaneous abdominal and gluteal AT. This study aimed to explore COMP's role in human subcutaneous abdominal and gluteal AT and preadipocyte biology.

Methods

COMP mRNA levels were measured in whole AT and immortalised preadipocytes via quantitative (q)-PCR. Tissue and cellular COMP protein were measured via Western blot and immunohistochemistry; plasma COMP was measured by ELISA. The effect of COMP on adipogenesis in immortalised preadipocytes was evaluated by qPCR of adipogenic markers and cellular triacylglycerol (TAG) accumulation.

Results

qPCR analysis of paired subcutaneous abdominal and gluteal AT biopsies (n = 190) across a range of BMI (20.7–45.5 kg/m²) indicated ∼3-fold higher COMP expression in gluteal AT (P = 1.7 × 10⁻³¹); protein levels mirrored this. Immunohistochemistry indicated COMP was abundant in gluteal AT ECM and co-localised with collagen-1. AT COMP mRNA levels and circulating COMP protein levels were positively associated with BMI/adiposity but unrelated to AT distribution. COMP expression changed dynamically during adipogenesis (time × depot, P = 0.01). Supplementation of adipogenic medium with exogenous COMP protein (500 ng/ml) increased PPARG2 expression ∼1.5-fold (P = 0.0003) and TAG accumulation ∼1.25-fold in abdominal and gluteal preadipocytes (P = 0.02).

Conclusions

We confirmed that COMP is an ECM protein which is differentially expressed between subcutaneous abdominal and gluteal AT. Despite its depot-specific expression pattern, however, AT COMP mRNA levels and plasma COMP concentration correlated positively with overall obesity but not body fat distribution. Exogenous COMP enhanced adipogenesis. These data identify COMP as a novel regulator of AT and highlight the importance of the ECM to AT biology.

•

COMP is a matricellular protein which is abundant in bone and cartilage.

•

COMP is differentially expressed between subcutaneous abdominal and gluteal AT.

•

COMP expression was positively correlated with overall AT mass but not distribution.

•

COMP promoted adipogenesis in subcutaneous abdominal and gluteal preadipocytes.

•

COMP represents a novel regulator of AT biology that resides in the ECM.

Association of serum ADAMTS-7 levels with left ventricular reverse remodeling after ST-elevation myocardial infarction

BACKGROUND

Left ventricular reverse remodeling (LVRR) in patients with ST-elevation myocardial infarction (STEMI) is associated with a good prognosis. Serum levels of ADAMTS-7 might be used for the prognosis of STEMI. This study aimed to investigate the relationship between serum ADAMTS-7 levels and LVRR.

METHODS

This was a prospective study of 104 patients with STEMI who underwent revascularization and 63 controls. ADAMTS-7 serum levels were measured on days 1, 3, and 7 and in months 1 and 6 after STEMI. A decrease ≥ 15% of the left ventricular end-systolic volume at 6 months was defined as LVRR.

RESULTS

The serum levels of ADAMTS-7 in patients with LVRR were lower than those without LVRR (3.84 ± 2.26 vs. 5.02 ± 2.54, P = 0.032) 7 days after STEMI and the difference between day 7 and day 1 (ΔADAMTS-7) was even significantly lower (- 1.31 ± 0.94 vs. - 0.30 ± 0.22, P = 0.021). Multivariate analysis showed that ΔADAMTS-7_{(day 7 minus day 1)} was independently associated with LVRR (OR = - 0.322, 95% CI = - 0.996 to - 0.074, P = 0.028). Receiver operating characteristic (ROC) curve analysis showed that LVRR could be predicted (sensitivity 89%, specificity 82%, and area under the curve 0.896) when ΔADAMTS-7_{(day 7 minus day 1)} was < - 0.39.

CONCLUSIONS

ΔADAMTS-7_{(day 7 minus day 1)} might be a potential predictive factor for LVRR.

Identification of genomic differences among peripheral arterial beds in atherosclerotic and healthy arteries

Calcification is independently associated with cardiovascular events and morbidity. The calcification burden in atherosclerotic lesions quantitatively and qualitatively differs between arterial beds. Cardiovascular risk factors (CVRF) differentially affect plaque development between arterial beds. The aim of this study was to evaluate the impact of CVRF on atherosclerotic plaque calcification and to further study the molecular arterial heterogeneity that could account for these differences. Histological analysis was performed on atherosclerotic plaques from 153 carotid, 97 femoral and 28 infrapopliteal arteries. CVRF showed minor associations with plaque calcification: age and hypertension affected only the overall presence of calcification but not the type of the calcification, which significantly differed between arterial beds. Transcriptome analysis revealed distinct gene expression profiles associated with each territory in atherosclerotic and healthy arteries. Canonical pathway analysis showed the preferential involvement of immune system-related processes in both atherosclerotic and healthy carotid arteries. Bone development-related genes were among those mostly enriched in atherosclerotic and healthy femoral arteries, which are more prone to developing endochondral calcification. This study highlights the heterogeneous nature of arteries from different peripheral vascular beds and contributes to a better understanding of atherosclerosis formation and evolution.

Species-specific regulation of angiogenesis by glucocorticoids reveals contrasting effects on inflammatory and angiogenic pathways

Glucocorticoids are potent inhibitors of angiogenesis in the rodent in vivo and in vitro but the mechanism by which this occurs has not been determined. Administration of glucocorticoids is used to treat a number of conditions in horses but the angiogenic response of equine vessels to glucocorticoids and, therefore, the potential role of glucocorticoids in pathogenesis and treatment of equine disease, is unknown. This study addressed the hypothesis that glucocorticoids would be angiostatic both in equine and murine blood vessels.The mouse aortic ring model of angiogenesis was adapted to assess the effects of cortisol in equine vessels. Vessel rings were cultured under basal conditions or exposed to: foetal bovine serum (FBS; 3%); cortisol (600 nM), cortisol (600nM) plus FBS (3%), cortisol (600nM) plus either the glucocorticoid receptor antagonist RU486 or the mineralocorticoid receptor antagonist spironolactone. In murine aortae cortisol inhibited and FBS stimulated new vessel growth. In contrast, in equine blood vessels FBS alone had no effect but cortisol alone, or in combination with FBS, dramatically increased new vessel growth compared with controls. This effect was blocked by glucocorticoid receptor antagonism but not by mineralocorticoid antagonism. The transcriptomes of murine and equine angiogenesis demonstrated cortisol-induced down-regulation of inflammatory pathways in both species but up-regulation of pro-angiogenic pathways selectively in the horse. Genes up-regulated in the horse and down-regulated in mice were associated with the extracellular matrix. These data call into question our understanding of glucocorticoids as angiostatic in every species and may be of clinical relevance in the horse.

Hypoxia decrease expression of cartilage oligomeric matrix protein to promote phenotype switching of pulmonary arterial smooth muscle cells

Extracellular matrix proteins play important roles in the development of pulmonary hypertension(pH). However, the role of Cartilage oligomeric matrix protein (COMP) in the development of hypoxia-induced pH is largely unknown. We tested the hypothesis that COMP deficiency induced by hypoxia leads to the phenotype switching of pulmonary arterial smooth muscle cells (PASMCs). The expression of COMP decreased in a chronic hypoxia rat pH model (P<0.05) and in PASMCs under hypoxia (3%O₂) (P<0.05). The expressions of differentiated marker proteins reduced in the pulmonary arteries from 5 month old COMP^-/- mice and in PASMCs under hypoxia or with the siRNA of COMP treatment under normoxia, but increased in PASMCs with adenovirus-increased COMP under hypoxia. The absorbance of cell counting kit-8 at 450nm and the expressions of proliferating cell nuclear antigen (PCNA) and osteopontin increased in PASMCs with the siRNA of COMP under normoxia (P<0.05). PCNA and osteopontin decreased in PASMCs with adenovirus-increased COMP under hypoxia (P<0.05). Additionally, the expression of bone morphogenetic protein receptor 2 (BMPR2) was reduced in COMP^-/- mice (P<0.01). Both mRNA and protein levels of bone morphogenetic protein 2 (BMP2) were lower in PASMCs with the siRNA of COMP (P<0.05). The protein level of BMP2 could be reversed by adenovirus-increased COMP under hypoxia (P<0.05). These data suggest that COMP could normally have a protective role against PASMC phenotype switching and maintain BMP2/BMPR2 signaling, and these protective actions could be lost as a result of hypoxia promoting a depletion of COMP.

Upregulation of ADAMTS‑7 and downregulation of COMP are associated with aortic aneurysm

Aortic aneurysm (AA) remains a fatal condition with high rates of morbidity and mortality, and the associated underlying mechanism influencing its pathology remains to be elucidated. A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-7 has previously been demonstrated to be involved in the pathogenesis of vascular atherosclerosis via degradation of cartilage oligomeric matrix protein (COMP). The ADAMTS-7/COMP pathway may therefore act as a potential therapeutic target for vascular disorders. To the best of the author's knowledge, the present study aimed to investigate for the first time, the expression of ADAMTS-7 and COMP in human AA. Human aortic aneurysm samples were collected from patients with AA (n=24), and ascending aorta control samples were harvested from dilated cardiomyopathy patients who underwent heart transplantation (n=18). Expression levels of ADAMTS-7 and matrix metalloproteinase-9 were significantly increased in the AA group, as detected by immunohistochemistry (P<0.05). The COMP protein level was markedly decreased in the AA group when compared with the control group, as demonstrated via immunohistochemistry and western blot analysis (P<0.05). The findings suggest that upregulation of ADAMTS-7 and downregulation of COMP are associated with induction of human AA. ADAMTS-7/COMP pathway may provide therefore act as a potential therapeutic target in human AA for efficient, optimal treatment interventions in the future.

Thrombospondins: A Role in Cardiovascular Disease

Thrombospondins (TSPs) represent extracellular matrix (ECM) proteins belonging to the TSP family that comprises five members. All TSPs have a complex multidomain structure that permits the interaction with various partners including other ECM proteins, cytokines, receptors, growth factors, etc. Among TSPs, TSP1, TSP2, and TSP4 are the most studied and functionally tested. TSP1 possesses anti-angiogenic activity and is able to activate transforming growth factor (TGF)-β, a potent profibrotic and anti-inflammatory factor. Both TSP2 and TSP4 are implicated in the control of ECM composition in hypertrophic hearts. TSP1, TSP2, and TSP4 also influence cardiac remodeling by affecting collagen production, activity of matrix metalloproteinases and TGF-β signaling, myofibroblast differentiation, cardiomyocyte apoptosis, and stretch-mediated enhancement of myocardial contraction. The development and evaluation of TSP-deficient animal models provided an option to assess the contribution of TSPs to cardiovascular pathology such as (myocardial infarction) MI, cardiac hypertrophy, heart failure, atherosclerosis, and aortic valve stenosis. Targeting of TSPs has a significant therapeutic value for treatment of cardiovascular disease. The activation of cardiac TSP signaling in stress and pressure overload may be therefore beneficial.

Extracellular matrix markers and risk of myocardial infarction: The HUNT Study in Norway

Aims Extracellular matrix remodelling may influence atherosclerotic progression and plaque stability. We hypothesized that evaluation of extracellular matrix markers, with potentially different roles during atherogenesis, could provide information on underlying mechanisms and risk of myocardial infarction (MI) in apparently healthy individuals. Methods We conducted a case-control study nested within the population-based HUNT2 cohort in Norway. A total of 58,761 men and women, free of known cardiovascular disease, were followed for a first MI. During 11.3 years of follow-up, 1587 incident MIs were registered, and these cases were compared with 3959 age- and sex-matched controls. Circulating levels of the ECM proteins CD147 (ECM metalloproteinase inducer; EMMPRIN), cartilage oligomeric matrix protein (COMP: thrombospondin-5) and YKL-40 (chitinase-3-like-1) were measured by enzyme immunoassays. Results We found an inverse association between COMP (quartile (Q) 4 vs. Q1: hazard ratio 0.81 (95% confidence interval: 0.67-0.98)) and YKL-40 (Q4 vs. Q1: hazard ratio 0.77 (0.62-0.95)) with incidence of MI after full multivariable adjustment. Serum CD147 was not associated with MI risk in adjusted analysis. Conclusion High levels of COMP and YKL-40 were associated with lower risk of incident MI, suggesting a potential beneficial role in promoting plaque stability in individuals without incident cardiovascular disease.

Genetic variants rs1994016 and rs3825807 in ADAMTS7 affect its mRNA expression in atherosclerotic occlusive peripheral arterial disease

AIM

Peripheral artery disease (PAD) is a vascular disease affecting peripheral circulation. Recently, genome-wide association studies revealed a relationship between single nucleotide polymorphisms (SNPs) in ADAMTS7 (a disintegrin and metalloprotease with thrombospondin motif 7) and atherosclerosis. In this study, we aimed to determine ADAMTS7 expression in peripheral blood mononuclear cells (PBMCs) and the frequency of ADAMTS7 rs1994016 and rs3825807 polymorphisms in a sample of Turkish patients with PAD, and to evaluate the association of matrix metalloproteinase (MMP) levels with PAD development.

METHODS

In this case-control study, ADAMTS7mRNA and protein expression was determined using reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and western blot, respectively, and rs1994016 and rs3825807 variants in ADAMTS7 were determined by real-time PCR in 115 PAD patients and 116 healthy controls. Plasma levels of nine MMPs were determined using a multiplex immunoassay system.

RESULTS

ADAMTS7mRNA levels were significantly higher in PAD patients than in controls (t=-2.75, P=.007). There was no significant difference in the frequencies of rs1994016 and rs3825807 between PAD patients and controls (P>.05). In PAD patients, ADAMTS7mRNA levels were significantly increased for the CC genotype of rs1994016 (t=-2.31, P=.026) and TT genotype of rs3825807 (t=-2.23, P=.032). Furthermore, plasma levels of MMP-1, MMP-3, MMP-7, MMP-10, MMP-12, and MMP-13 were significantly higher in PAD patients than in controls (P<.05).

CONCLUSION

This is the first report of the relationship between PAD and ADAMTS7 expression and the effects of the rs1994016 and rs3825807 variants on PAD development. ADAMTS7 may be associated with PAD development.

Identification of Differentially Expressed Genes in Pelvic Organ Prolapse by RNA-Seq

Background

Pelvic organ prolapse (POP) brings major health issues for women, affecting 40% of postmenopausal women, and directly affects bladder and bowel function, as well as quality of life. In light of the projected growth in demand for care for pelvic floor disorders, determining the etiology and progression of POP has important public health implications.

Material/Methods

Uterosacral ligaments (USLs) samples of POP patients and normal controls were enrolled for RNA-Seq, and functional annotation analysis and Protein-Protein interaction (PPI) networks construction were performed for differentially expressed genes (DEGs).

Results

A total of 81 DEGs were identified between POP and normal control, and distinctly classify all samples into normal and POP group by hierarchical clustering. Sixty-six DEGs demonstrated the same expression pattern among the POP samples with different stages. For those DEGs, canonical Wnt receptor signaling pathway was the most significantly enriched GO term (P value=3.33E-07), and neuroactive ligand-receptor interaction was the most significantly enriched pathway (P value=1.24E-03). In The PPI networks of 81 dysregulated genes, significant hub proteins contained TOP2A (Degree=54), KCNA5 (Degree=22) and PLA2G2A (Degree=19), suggesting their important role in the development of POP.

Conclusions

This RNA-seq analysis identified a POP signature of 81 genes, and some ECM-related genes, including COMP, NDP, and SNAI2 might participate in the pathology of POP and be applied as potential therapeutic targets.

Thrombospondins in the transition from myocardial infarction to heart failure

The heart's reaction to ischemic injury from a myocardial infarction involves complex cross-talk between the extra-cellular matrix (ECM) and different cell types within the myocardium. The ECM functions not only as a scaffold where myocytes beat synchronously, but an active signaling environment that regulates the important post-MI responses. The thrombospondins are matricellular proteins that modulate cell--ECM interactions, functioning as "sensors" that mediate outside-in and inside-out signaling. Thrombospondins are highly expressed during embryonic stages, and although their levels decrease during adult life, can be re-expressed in high quantities in response to cardiac stress including myocardial infarction and heart failure. Like a Swiss-army knife, the thrombospondins possess many tools: numerous binding domains that allow them to interact with other elements of the ECM, cell surface receptors, and signaling molecules. It is through these that the thrombospondins function. In the present review, we provide basic as well as clinical evidence linking the thrombospondin proteins with the post myocardial infarction response, including inflammation, fibrotic matrix remodeling, angiogenesis, as well as myocyte hypertrophy, apoptosis, and contractile dysfunction in heart failure. We will describe what is known regarding the intracellular signaling pathways that are involved with these responses, paving the road for future studies identifying these proteins as therapeutic targets for cardiac disease.

The Function and Roles of ADAMTS-7 in Inflammatory Diseases

The ADAMTS proteinases are a group of multidomain and secreted metalloproteinases containing the thrombospondin motifs. ADAMTS-7 is a member of ADAMTS family and plays a crucial role in the pathogenesis of arthritis. Overexpression of ADAMTS-7 gene promotes the breakdown of cartilage oligomeric matrix protein (COMP) matrix and accelerates the progression of both surgically induced osteoarthritis and collagen-induced arthritis. Moreover, ADAMTS-7 and tumor necrosis factor-α (TNF-α) form a positive feedback loop in osteoarthritis. More significantly, granulin-epithelin precursor, a growth factor has important roles in bone development and bone-associated diseases, disturbs the interaction between ADAMTS-7 and COMP, and prevents COMP degradation. This review is based on our results and provides an overview of current knowledge of ADAMTS-7, including its structure, function, gene regulation, and inflammatory diseases involvement.

ADAMTS7 locus confers high cross-race risk for development of coronary atheromatous plaque

Genome-wide association studies of coronary artery disease (CAD) have recently identified a new susceptibility locus, ADAMTS7, in subjects of European ancestry. However, the significance of this locus in Chinese populations has not been identified. Therefore, this study was designed to evaluate the effect of rs3825807, a non-synonymous variant in the prodomain of the ADAMTS7 protease, on CAD risk and atherosclerosis severity in a Chinese population. We performed genetic association analyses in two independent case-control cohorts, which included a total of 8154 participants. Additionally, the association between the ADAMTS7 rs3825807 genotype and the proportion of CAD patients with 3- and 1-vessel disease was tested. We found that ADAMTS7 rs3825807 was associated with susceptibility to CAD in a Chinese population [odds ratio (OR) = 1.15, 95 % confidence interval (CI) = 1.05-1.26, P = 0.002]. The association remained significant after adjusting for clinical covariates (adjusted OR = 1.12, 95 % CI = 1.02-1.24, P = 0.02). Among 3741 angiographically documented CAD patients, the rs3825807 risk allele showed a significant association with disease severity (P = 0.04, trend P = 0.02). Additionally, 3-vessel disease demonstrated a strong and direct association with ADAMTS7 rs3825807 gene dosage (P = 0.02). Overall, our findings indicate that the significant associations observed between this coding variant in ADAMTS7 and the risk of CAD development are cross-ethnic, and the gene dosage is consistent with the degree of coronary atheromatous burden.

Thrombospondin-1, -2 and -5 have differential effects on vascular smooth muscle cell physiology

INTRODUCTION

The thrombospondins (TSPs) are matricellular proteins that exert multifunctional effects by binding cytokines, cell-surface receptors and other proteins. TSPs play important roles in vascular pathobiology and are all expressed in arterial lesions. The differential effects of TSP-1, -2, and -5 represent a gap in knowledge in vascular smooth muscle cell (VSMC) physiology. Our objective is to determine if structural differences of the TSPs imparted different effects on VSMC functions critical to the formation of neointimal hyperplasia. We hypothesize that TSP-1 and -2 induce similar patterns of migration, proliferation and gene expression, while the effects of TSP-5 are different.

METHODS

Human aortic VSMC chemotaxis was tested for TSP-2 and TSP-5 (1-40 μg/mL), and compared to TSP-1 and serum-free media (SFM) using a modified Boyden chamber. Next, VSMCs were exposed to TSP-1, TSP-2 or TSP-5 (0.2-40 μg/mL). Proliferation was assessed by MTS assay. Finally, VSMCs were exposed to TSP-1, TSP-2, TSP-5 or SFM for 3, 6 or 24 h. Quantitative real-time PCR was performed on 96 genes using a microfluidic card. Statistical analysis was performed by ANOVA or t-test, with p < 0.05 being significant.

RESULTS

TSP-1, TSP-2 and TSP-5 at 20 μg/mL all induce chemotaxis 3.1 fold compared to serum-free media. TSP-1 and TSP-2 induced proliferation 53% and 54% respectively, whereas TSP-5 did not. In the gene analysis, overall, cardiovascular system development and function is the canonical pathway most influenced by TSP treatment, and includes multiple growth factors, cytokines and proteases implicated in cellular migration, proliferation, vasculogenesis, apoptosis and inflammation pathways.

CONCLUSIONS AND RELEVANCE

The results of this study indicate TSP-1, -2, and -5 play active roles in VSMC physiology and gene expression. Similarly to TSP-1, VSMC chemotaxis to TSP-2 and -5 is dose-dependent. TSP-1 and -2 induces VSMC proliferation, but TSP-5 does not, likely due conservation of N-terminal domains in TSP-1 and -2. In addition, TSP-1, -2 and -5 significantly affect VSMC gene expression; however, little overlap exists in the specific genes altered. This study further delineates TSP-1, -2 and -5's contributions to processes related to VSMC physiology.

Association between plasma ADAMTS-7 levels and ventricular remodeling in patients with acute myocardial infarction

Background

The metalloproteinase family of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) degrades extracellular matrix. However, the relevance of the ADAMTS family to cardiovascular diseases remains largely unknown. The study aimed to examine plasma ADAMTS-7 levels in patients with acute myocardial infarction (AMI) and the relationship between plasma ADAMTS-7 levels and heart function.

Methods

This was a prospective study performed in 84 patients with ST-elevation myocardial infarction (STEMI), 70 patients with non-STEMI (NSTEMI), and 38 controls. Enzyme-linked immunosorbent assay (ELISA) was used to measure plasma ADAMTS-7 levels. Cardiac structure and function were assessed using two-dimensional transthoracic echocardiography. Patients were stratified according to left ventricular ejection fraction (LVEF) ≤35% or >35%.

Results

Plasma ADAMTS-7 levels were higher in patients with LVEF ≤35% compared with those with LVEF >35% (6.73 ± 2.47 vs. 3.22 ± 2.05 ng/ml, P < 0.05). Plasma ADAMTS-7 levels were positively correlated with brain natriuretic peptide (BNP), left ventricular mass index (LVMI), left ventricular end-diastolic diameter (LVEDD), and left ventricular end-systolic diameter (LVESD) and negatively correlated with the 6-min walk test (P < 0.05). According to the receiver operating characteristic (ROC) curve, using a cutoff value of plasma ADAMTS-7 of 5.69 ng/ml was associated with a specificity of 61.0% and a sensitivity of 87.6% for the diagnosis of heart failure after AMI. Logistic regression analysis indicated that the association between ADAMTS-7 and heart failure after AMI was independent from traditional cardiovascular risk factors and other biomarkers (odds ratio = 1.236, 95% confidence interval: 1.023 to 1.378, P = 0.021).

Conclusions

Elevated ADAMTS-7 level may be involved in ventricular remodeling after AMI.

Knockout of Adamts7, a novel coronary artery disease locus in humans, reduces atherosclerosis in mice

BACKGROUND

Genome-wide association studies have established ADAMTS7 as a locus for coronary artery disease in humans. However, these studies fail to provide directionality for the association between ADAMTS7 and coronary artery disease. Previous reports have implicated ADAMTS7 in the regulation of vascular smooth muscle cell migration, but a role for and the direction of impact of this gene in atherogenesis have not been shown in relevant model systems.

METHODS AND RESULTS

We bred an Adamts7 whole-body knockout mouse onto both the Ldlr and Apoe knockout hyperlipidemic mouse models. Adamts7(-/-)/Ldlr(-/-) and Adamts7(-/-)/Apoe(-/-) mice displayed significant reductions in lesion formation in aortas and aortic roots compared with controls. Adamts7 knockout mice also showed reduced neointimal formation after femoral wire injury. Adamts7 expression was induced in response to injury and hyperlipidemia but was absent at later time points, and primary Adamts7 knockout vascular smooth muscle cells showed reduced migration in the setting of tumor necrosis factor-α stimulation. ADAMTS7 localized to cells positive for smooth muscle cell markers in human coronary artery disease lesions, and subcellular localization studies in cultured vascular smooth muscle cells placed ADAMTS7 at the cytoplasm and cell membrane, where it colocalized with markers of podosomes.

CONCLUSIONS

These data represent the first in vivo experimental validation of the association of Adamts7 with atherogenesis, likely through modulation of vascular cell migration and matrix in atherosclerotic lesions. These results demonstrate that Adamts7 is proatherogenic, lending directionality to the original genetic association and supporting the concept that pharmacological inhibition of ADAMTS7 should be atheroprotective in humans, making it an attractive target for novel therapeutic interventions.

Cartilage oligomeric matrix protein-induced complement activation in systemic sclerosis

Introduction

Complexes between cartilage oligomeric matrix protein (COMP) and the complement activation product C3b have been found in the circulation of patients with rheumatoid arthritis and systemic lupus erythematosus. In systemic sclerosis (SSc) COMP expression in the skin is upregulated both in lesional and non-lesional skin, which is also reflected in an increased amount of circulating COMP. We investigated the presence of COMP-C3b complexes in serum and skin biopsies of patients with SSc.

Methods

The presence of COMP and COMP-C3b complexes in the serum of 80 patients with limited cutaneous SSc (lcSSc, n = 40) and diffuse cutaneous SSc (dcSSc, n = 40) and 97 healthy controls was measured by ELISA and correlated to different clinical parameters. Samples were collected both at baseline and after three to five years to assess longitudinal changes in COMP-C3b complex levels. Furthermore, skin biopsies from seven patients with dcSSc and three healthy controls were analyzed for expression of COMP and deposition of C3b and IgG.

Results

Serum levels of COMP-C3b were found to be elevated in both dcSSc and lcSSc compared to healthy controls and decreased at the second measurement in patients on immunosuppressive therapy. No co-localization of COMP and C3b was found in the skin biopsies, indicating that the COMP-C3b complexes are formed upon release of COMP into the circulation.

Conclusion

COMP-C3b complexes are found in the serum of patients with SSc. The lack of co-localization between COMP and C3b in the skin suggests that COMP does not drive complement activation in the skin in SSc.

Cartilage oligomeric matrix protein (COMP) in murine brachiocephalic and carotid atherosclerotic lesions

OBJECTIVE

To investigate the hypothesis that COMP can influence the morphology, stability and size of murine atherosclerotic lesions.

METHODS

ApoE- and ApoE/COMP-knockout mice were fed a high-fat diet to develop atherosclerotic plaques at lesion sites of three different types; inflammatory and fibrous plaques induced in the carotid artery by low or oscillatory shear stress, respectively, and spontaneously developing plaques in the brachiocephalic artery. The localization of COMP in the plaques and the effect of COMP deficiency on plaque development were evaluated.

RESULTS

COMP immunoreactivity was observed in about half of the investigated plaques from the ApoE null mice, mainly located along the intima-medial border. There were no significant differences in the size of inflammatory and fibrous carotid plaques between the genotypes. Plaques in the brachiocephalic artery from ApoE mice lacking COMP were increased in size with 54%. In these plaques the collagen content was also increased by 48%. There were no differences in relative collagen content in inflammatory and fibrous carotid plaques between genotypes. Polarized light microscopy showed that the increase in total collagen in brachiocephalic plaques was more than proportionally accounted for by an increase in thicker collagen fibrils.

CONCLUSION

We have shown that COMP deficiency has a significant impact on atherosclerotic plaque morphology and size. Our data also suggest that an altered collagen metabolism may be an important mechanism in this finding.

Control of organization and function of muscle and tendon by thrombospondin-4

Thrombospondins (TSPs) are multifunctional proteins that are deposited in the extracellular matrix where they directly affect the function of vascular and other cell types. TSP-4, one of the 5 TSP family members, is expressed abundantly in tendon and muscle. We have examined the effect of TSP-4 deficiency on tendon collagen and skeletal muscle morphology and function. In Thbs4(-/-) mice, tendon collagen fibrils are significantly larger than in wild-type mice, and there is no compensatory over-expression of TSP-3 and TSP-5, the two TSPs most highly homologous to TSP-4, in the deficient mice. TSP-4 is expressed in skeletal muscle, and higher levels of TSP-4 protein are associated with the microvasculature of red skeletal muscle with high oxidative metabolism. Lack of TSP-4 in medial soleus, red skeletal muscle with predominant oxidative metabolism, is associated with decreased levels of several specific glycosaminoglycan modifications, decreased expression of a TGFβ receptor beta-glycan, decreased activity of lipoprotein lipase, which associates with vascular cell surfaces by binding to glycosaminoglycans, and decreased uptake of VLDL. The soleus muscle is smaller and hind- and fore-limb grip strength is reduced in Thbs4(-/-) mice compared to wild-type mice. These observations suggest that TSP-4 regulates the composition of the ECM at major sites of its deposition, tendon and muscle, and the absence of TSP-4 alters the organization, composition and physiological functions of these tissues.

Thrombospondins, potential drug targets for cardiovascular diseases

The thrombospondin (TSP) family consists of five multimeric, multidomain calcium-binding glycoproteins that act as regulators of cell-cell and cell-matrix associations as well as interact with other extracellular matrix molecules affecting their function. Increasing interest on cardiac TSP-1, TSP-2 and TSP-4 has emerged, and they have been studied in cardiac hypertrophy, myocardial infarction, heart failure, atherosclerosis and aortic valve stenosis. The aim of this MiniReview is to summarize the current knowledge on each TSP in various cardiovascular pathologies. We specifically emphasize the role of TSPs in cardiac remodelling and evaluate TSPs as potential cardiovascular drug targets. Thrombospondin-1 (TSP-1) is the most studied TSP, being antiangiogenic and able to activate transforming growth factor-β. The functions of TSP-2 and TSP-4 are linked in maintaining the composition of the matrix of the hypertrophied heart, whereas there is very little knowledge on cardiac TSP-3 and TSP-5. TSP-1, TSP-2 and TSP-4 have been shown to affect cardiac remodelling in vivo, for example, by modulating matrix metalloproteinase and transforming growth factor-β activity, collagen synthesis, myofibroblast differentiation, cell death and stretch-mediated augmentation of cardiac contractility. The detrimental role for TSPs in cardiovascular pathophysiology has been clearly demonstrated in knockout mouse models, and augmentation of TSP signalling in the heart during stress and haemodynamic overload might be beneficial. In conclusion, the role of TSP-1, TSP-2 and TSP-4 in cardiac hypertrophy, remodelling after myocardial infarction, heart failure, atherosclerosis and aortic valve stenosis encourages further investigation to validate them as potential drug targets.

Identification, prioritization, and evaluation of glycoproteins for aggressive prostate cancer using quantitative glycoproteomics and antibody-based assays on tissue specimens

Prostate cancer is highly heterogeneous in nature; while the majority of cases are clinically insignificant, some cases are lethal. Currently, there are no reliable screening methods for aggressive prostate cancer. Since most established serum and urine biomarkers are glycoproteins secreted or leaked from the diseased tissue, the current study seeks to identify glycoprotein markers specific to aggressive prostate cancer using tissue specimens. With LC-MS/MS glycoproteomic analysis, we identified 350 glycopeptides with 17 being altered in aggressive prostate cancer. ELISA assays were developed/purchased to evaluate four candidates, that is, cartilage oligomeric matrix protein (COMP), periostin, membrane primary amine oxidase (VAP-1), and cathepsin L, in independent tissue sets. In agreement with the proteomic analysis, we found that COMP and periostin expressions were significantly increased in aggressive prostate tumors while VAP-1 expression was significantly decreased in aggressive tumor. In addition, the expression of these proteins in prostate metastases also follows the same pattern observed in the proteomic analysis. This study provides a workflow for biomarker discovery, prioritization, and evaluation of aggressive prostate cancer markers using tissue specimens. Our data suggest that increase in COMP and periostin and decrease in VAP-1 expression in the prostate may be associated with aggressive prostate cancer.

Molecular basis of antiangiogenic thrombospondin-1 type 1 repeat domain interactions with CD36

OBJECTIVE

Antiangiogenic activity of thrombospondin-1 and related proteins is mediated by interactions between thrombospondin type 1 repeat (TSR) domains and the CD36, LIMP-2, Emp sequence homology (CLESH) domain of the endothelial cell receptor CD36. We sought to characterize key molecular determinants of the interaction between thrombospondin-1 TSR domains and the CD36 CLESH domain.

APPROACH AND RESULTS

Recombinant thrombospondin-1 TSR2 and TSR(2,3) constructs inhibited microvascular endothelial cell migration, microvascular endothelial cell tube formation, and vessel sprouting in aortic ring assays. Interaction with CD36 CLESH decoy peptides negated these effects. Mutational analyses identified a cluster of residues that confer positive charge to the TSR2 surface and mediate interaction with CD36 CLESH. Antiangiogenic activity was significantly reduced by charge-neutralizing mutations of the Arg-Trp ladder in TSR2, but not TSR3. Additionally, I438 and K464 of TSR2 were shown to be required for CD36 CLESH binding to TSR2. A complementary acidic cluster within CD36 CLESH is also required for antiangiogenic activity.

CONCLUSIONS

Thrombospondin-1 interacts with CD36 CLESH through electrostatic interactions mediated by a positively charged TSR2 surface and multiple negatively charged CD36 CLESH residues. Two key residues serve as specificity determinants that identify other TSR domains that interact with CD36 CLESH.

ADAMTS7 cleavage and vascular smooth muscle cell migration is affected by a coronary-artery-disease-associated variant

Recent genome-wide association studies have revealed an association between variation at the ADAMTS7 locus and susceptibility to coronary artery disease (CAD). Furthermore, in a population-based study cohort, we observed an inverse association between atherosclerosis prevalence and rs3825807, a nonsynonymous SNP (A to G) leading to a Ser-to-Pro substitution in the prodomain of the protease ADAMTS7. In light of these data, we sought a mechanistic explanation for this association. We found that ADAMTS7 accumulated in smooth muscle cells in coronary and carotid atherosclerotic plaques. Vascular smooth muscle cells (VSMCs) of the G/G genotype for rs3825807 had reduced migratory ability, and conditioned media of VSMCs of the G/G genotype contained less of the cleaved form of thrombospondin-5, an ADAMTS7 substrate that had been shown to be produced by VSMCs and inhibit VSMC migration. Furthermore, we found that there was a reduction in the amount of cleaved ADAMTS7 prodomain in media conditioned by VSMCs of the G/G genotype and that the Ser-to-Pro substitution affected ADAMTS7 prodomain cleavage. The results of our study indicate that rs3825807 has an effect on ADAMTS7 maturation, thrombospondin-5 cleavage, and VSMC migration, with the variant associated with protection from atherosclerosis and CAD rendering a reduction in ADAMTS7 function.