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Biochemical Pharmacology Aug 2019Lung cancers have a predilection for metastasizing to bone. The matricellular glycoprotein thrombospondin (TSP)-2 regulates multiple biological functions and has a...
Lung cancers have a predilection for metastasizing to bone. The matricellular glycoprotein thrombospondin (TSP)-2 regulates multiple biological functions and has a critical role in tumor development and metastasis, although its effects are uncertain in lung cancer bone metastasis. This study demonstrates that TSP-2 expression is highly correlated with lung cancer tumor stage and that the TSP-2 neutralizing antibody reduces osteoclast formation in conditioned medium obtained from lung cancer cells. We also found that TSP-2 promotes osteoclastogenesis through the RANKL-dependent pathway and that TSP-2-mediated osteoclastogenesis involves the transactivation of nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) via the inhibition of miR-486-3p expression. Osteoblasts played a critical role in osteoclast differentiation and incubation of osteoblasts with TSP-2 altered the RANKL:OPG ratio. Furthermore, TSP-2 knockdown inhibited lung cancer osteolytic metastasis in vivo. TSP-2 appears to be worth targeting for the prevention of bone metastasis in lung cancer.
Topics: A549 Cells; Animals; Bone Neoplasms; Humans; Lung Neoplasms; Mice; Mice, Nude; Osteoclasts; Osteogenesis; RANK Ligand; RAW 264.7 Cells; Thrombospondins
PubMed: 31075265
DOI: 10.1016/j.bcp.2019.05.005 -
The International Journal of... Jun 2004GeneQuest was a high throughput, large-scale analysis of single nucleotide polymorphisms (SNPs) to identify gene associated with familial, premature coronary artery... (Review)
Review
GeneQuest was a high throughput, large-scale analysis of single nucleotide polymorphisms (SNPs) to identify gene associated with familial, premature coronary artery disease and myocardial infarction. The three SNPs showing the highest and most significant associations with disease were all members of the thrombospondin gene family, thrombospondin-1, thrombospondin-2 and thrombospondin-4. These unanticipated associations have kindled efforts to understand how the three SNPs influence the structures and functions of the thrombospondins. The SNP in thrombospondin-1 and thrombospondin-4 reside in their coding regions and result in single amino acid changes: in thrombospondin-1, the predominant asparagine at position 700 is changed to a serine while, in thrombospondin-4, it is a change of an alanine to a proline at position 387. The SNP in thrombospondin-2 is a base change in the 3'-untranslated region of the mRNA. At this early stage of investigation, predictive analyses suggest that the substitutions in thrombospondin-2 and thrombospondin-4 should alter structure, and there is direct evidence to indicate that the thrombospondin-1 SNP alters conformational stability. In addition, profound differences in the function of the thrombospondin-4 SNP variants have been identified with respect to their capacity to support endothelial cell adhesion and proliferation. While substantial additional information is needed to understand if and how the polymorphic forms of the thrombospondins affect coronary artery disease, the data assembled to date suggest marked effects of these SNPs on the structures and functions of the thrombospondins, which are consistent with induction of a proatherogenic and prothrombotic phenotype.
Topics: Binding Sites; Calcium-Binding Proteins; Coronary Artery Disease; Fibroblast Growth Factors; Humans; Polymorphism, Single Nucleotide; Protein Structure, Secondary; Protein Structure, Tertiary; Thrombospondins
PubMed: 15094117
DOI: 10.1016/j.biocel.2004.01.005 -
The New England Journal of Medicine Dec 2014Idiopathic membranous nephropathy is an autoimmune disease. In approximately 70% of patients, it is associated with autoantibodies against the phospholipase A2 receptor...
BACKGROUND
Idiopathic membranous nephropathy is an autoimmune disease. In approximately 70% of patients, it is associated with autoantibodies against the phospholipase A2 receptor 1 (PLA2R1). Antigenic targets in the remaining patients are unknown.
METHODS
Using Western blotting, we screened serum samples from patients with idiopathic membranous nephropathy, patients with other glomerular diseases, and healthy controls for antibodies against human native glomerular proteins. We partially purified a putative new antigen, identified this protein by means of mass spectrometry of digested peptides, and validated the results by analysis of recombinant protein expression, immunoprecipitation, and immunohistochemical analysis.
RESULTS
Serum samples from 6 of 44 patients in a European cohort and 9 of 110 patients in a Boston cohort with anti-PLA2R1-negative idiopathic membranous nephropathy recognized a glomerular protein that was 250 kD in size. None of the serum samples from the 74 patients with idiopathic membranous nephropathy who were seropositive for anti-PLA2R1 antibodies, from the 76 patients with other glomerular diseases, and from the 44 healthy controls reacted against this antigen. Although this newly identified antigen is clearly different from PLA2R1, it shares some biochemical features, such as N-glycosylation, membranous location, and reactivity with serum only under nonreducing conditions. Mass spectrometry identified this antigen as thrombospondin type-1 domain-containing 7A (THSD7A). All reactive serum samples recognized recombinant THSD7A and immunoprecipitated THSD7A from glomerular lysates. Moreover, immunohistochemical analyses of biopsy samples from patients revealed localization of THSD7A to podocytes, and IgG eluted from one of these samples was specific for THSD7A.
CONCLUSIONS
In our cohort, 15 of 154 patients with idiopathic membranous nephropathy had circulating autoantibodies to THSD7A but not to PLA2R1, a finding that suggests a distinct subgroup of patients with this condition. (Funded by the French National Center for Scientific Research and others.).
Topics: Autoantibodies; Blotting, Western; Case-Control Studies; Glomerulonephritis, Membranous; Humans; Kidney Glomerulus; Receptors, Phospholipase A2; Thrombospondins
PubMed: 25394321
DOI: 10.1056/NEJMoa1409354 -
FASEB Journal : Official Publication of... Feb 2023Thrombospondin-2 (Tsp2), a glycoprotein in the extracellular matrix, plays a critical role in the maintenance of vascular homeostasis. However, its role in the...
Thrombospondin-2 (Tsp2), a glycoprotein in the extracellular matrix, plays a critical role in the maintenance of vascular homeostasis. However, its role in the pathogenesis of cardiovascular disorders such as intimal hyperplasia is not fully elucidated. This study, therefore, aims to explore the effect of Tsp2 on intimal hyperplasia and its associated underlying mechanisms. Intimal hyperplasia (IH) was established using a modified wire-mediated femoral artery injury model. Immunofluorescence and qPCR identified upregulated Tsp2 expression in the injured femoral artery compared with the uninjured femoral artery. Similarly, TSP2 expression was also increased in human samples from the atherosclerotic femoral artery and colocalized with vascular smooth muscle cells (VSMCs). Compared with the wild-type littermates, Tsp2 knockout mice displayed a mitigated IH in the injured femoral artery, as demonstrated by a decreased neointimal area and intimal/median ratio. Primary mouse VSMCs were cultured to explore the mechanism by which Tsp2 influenced IH in vitro. PDGF-stimulated VSMCs presented an elevated Tsp2 expression and enhanced migration and proliferation. However, Tsp2 knockdown by siRNA blocked the increased migration and proliferation of VSMCs. Further analysis identified an association between Notch3 and IH when the intracellular domain of Notch3 (Nicd3) was upregulated in PDGF-stimulated VSMCs and femoral arteries with IH in human tissues. Along with the overexpression and downregulation of Tsp2, the Nicd3 expression was also up and downregulated accordingly. Tsp2 was associated with IH and may serve as a therapeutic target for IH. Downregulation of Tsp2 could mitigate the progression of IH by modulating the proliferation and migration of VSMCs.
Topics: Animals; Humans; Mice; Cell Movement; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Hyperplasia; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Thrombospondins
PubMed: 36645109
DOI: 10.1096/fj.202201040R -
Cardiovascular Research Jan 2016
Topics: Amino Acid Sequence; Cell Adhesion Molecules, Neuronal; Humans; Hypertension, Pulmonary; Thrombospondin 1; Thrombospondins
PubMed: 26604038
DOI: 10.1093/cvr/cvv258 -
Biochemical Pharmacology Jun 2019A Disintegrin and Metalloproteinase (ADAM) is a family of proteolytic enzymes that possess sheddase function and regulate shedding of membrane-bound proteins, growth... (Review)
Review
A Disintegrin and Metalloproteinase (ADAM) is a family of proteolytic enzymes that possess sheddase function and regulate shedding of membrane-bound proteins, growth factors, cytokines, ligands and receptors. Typically, ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and a characteristic transmembrane domain. Most ADAMs are activated by proprotein convertases, but can also be regulated by G-protein coupled receptor agonists, Ca ionophores and protein kinase C activators. A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) is a family of secreted enzymes closely related to ADAMs. Like ADAMs, ADAMTS members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but they lack a transmembrane domain and instead have characteristic thrombospondin motifs. Activated ADAMs perform several functions and participate in multiple cardiovascular processes including vascular smooth muscle cell proliferation and migration, angiogenesis, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs may also be involved in pathological conditions and cardiovascular diseases such as atherosclerosis, hypertension, aneurysm, coronary artery disease, myocardial infarction and heart failure. Like ADAMs, ADAMTS have a wide-spectrum role in vascular biology and cardiovascular pathophysiology. ADAMs and ADAMTS activity is naturally controlled by endogenous inhibitors such as tissue inhibitors of metalloproteinases (TIMPs), and their activity can also be suppressed by synthetic small molecule inhibitors. ADAMs and ADAMTS can serve as important diagnostic biomarkers and potential therapeutic targets for cardiovascular disorders. Natural and synthetic inhibitors of ADAMs and ADAMTS could be potential therapeutic tools for the management of cardiovascular diseases.
Topics: ADAM Proteins; Amino Acid Motifs; Animals; Disintegrins; Endothelium, Vascular; Humans; Matrix Metalloproteinase Inhibitors; Thrombospondins; Vascular Diseases
PubMed: 30905657
DOI: 10.1016/j.bcp.2019.03.033 -
Blood Advances Feb 2024Immunomodulatory drugs (IMiDs) are key drugs for treating multiple myeloma and myelodysplastic syndrome with chromosome 5q deletion. IMiDs exert their pleiotropic...
Immunomodulatory drugs (IMiDs) are key drugs for treating multiple myeloma and myelodysplastic syndrome with chromosome 5q deletion. IMiDs exert their pleiotropic effects through the interaction between cell-specific substrates and cereblon, a substrate receptor of the E3 ubiquitin ligase complex. Thus, identification of cell-specific substrates is important for understanding the effects of IMiDs. IMiDs increase the risk of thromboembolism, which sometimes results in fatal clinical outcomes. In this study, we sought to clarify the molecular mechanisms underlying IMiDs-induced thrombosis. We investigated cereblon substrates in human megakaryocytes using liquid chromatography-mass spectrometry and found that thrombospondin-1 (THBS-1), which is an inhibitor of a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13, functions as an endogenous substrate in human megakaryocytes. IMiDs inhibited the proteasomal degradation of THBS-1 by impairing the recruitment of cereblon to THBS-1, leading to aberrant accumulation of THBS-1. We observed a significant increase in THBS-1 in peripheral blood mononuclear cells as well as larger von Willebrand factor multimers in the plasma of patients with myeloma, who were treated with IMiDs. These results collectively suggest that THBS-1 represents an endogenous substrate of cereblon. This pairing is disrupted by IMiDs, and the aberrant accumulation of THBS-1 plays an important role in the pathogenesis of IMiDs-induced thromboembolism.
Topics: Humans; Adaptor Proteins, Signal Transducing; Immunomodulating Agents; Leukocytes, Mononuclear; Multiple Myeloma; Thromboembolism; Thrombospondins
PubMed: 38163319
DOI: 10.1182/bloodadvances.2023010080 -
Molecular Biology and Evolution Jun 2019Extracellular matrix (ECM) is considered central to the evolution of metazoan multicellularity; however, the repertoire of ECM proteins in nonbilaterians remains... (Comparative Study)
Comparative Study
Extracellular matrix (ECM) is considered central to the evolution of metazoan multicellularity; however, the repertoire of ECM proteins in nonbilaterians remains unclear. Thrombospondins (TSPs) are known to be well conserved from cnidarians to vertebrates, yet to date have been considered a unique family, principally studied for matricellular functions in vertebrates. Through searches utilizing the highly conserved C-terminal region of TSPs, we identify undisclosed new families of TSP-related proteins in metazoans, designated mega-TSP, sushi-TSP, and poriferan-TSP, each with a distinctive phylogenetic distribution. These proteins share the TSP C-terminal region domain architecture, as determined by domain composition and analysis of molecular models against known structures. Mega-TSPs, the only form identified in ctenophores, are typically >2,700 aa and are also characterized by N-terminal leucine-rich repeats and central cadherin/immunoglobulin domains. In cnidarians, which have a well-defined ECM, Mega-TSP was expressed throughout embryogenesis in Nematostella vectensis, with dynamic endodermal expression in larvae and primary polyps and widespread ectodermal expression in adult Nematostella vectensis and Hydra magnipapillata polyps. Hydra Mega-TSP was also expressed during regeneration and siRNA-silencing of Mega-TSP in Hydra caused specific blockade of head regeneration. Molecular phylogenetic analyses based on the conserved TSP C-terminal region identified each of the TSP-related groups to form clades distinct from the canonical TSPs. We discuss models for the evolution of the newly defined TSP superfamily by gene duplications, radiation, and gene losses from a debut in the last metazoan common ancestor. Together, the data provide new insight into the evolution of ECM and tissue organization in metazoans.
Topics: Animals; Anthozoa; Biological Evolution; Hydra; Invertebrates; Multigene Family; Thrombospondins
PubMed: 30863851
DOI: 10.1093/molbev/msz060 -
Genome Biology May 2015The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have... (Review)
Review
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future.
Topics: ADAM Proteins; Animals; Arthritis; Cardiovascular Diseases; Catalytic Domain; Disease Models, Animal; Disintegrins; Endopeptidases; Evolution, Molecular; Extracellular Matrix; Gene Expression Regulation; Humans; Multigene Family; Neoplasms; Substrate Specificity; Thrombospondins
PubMed: 26025392
DOI: 10.1186/s13059-015-0676-3 -
Cold Spring Harbor Perspectives in... May 2012Thrombospondins TSP-1 and TSP-2 are potent endogenous inhibitors of angiogenesis. They inhibit angiogenesis through direct effects on endothelial cell migration,... (Review)
Review
Thrombospondins TSP-1 and TSP-2 are potent endogenous inhibitors of angiogenesis. They inhibit angiogenesis through direct effects on endothelial cell migration, proliferation, survival, and apoptosis and by antagonizing the activity of VEGF. Several of the membrane receptor systems and signal transduction molecules that mediate the effects of TSP-1 and TSP-2 have been elucidated. TSP-1 and TSP-2 exert their direct effects through CD36, CD47, and integrins. Recent data indicate that CD36 and β1 integrins collaborate to transmit the signals that are initiated by TSP-1 and TSP-2. Furthermore, these receptors appear to associate with VEGFR2 to form a platform for the integration of positive and negative signals for angiogenesis. Cross talk between pro- and antiangiogenic signal transduction pathways may enable TSP-1 and TSP-2 to inhibit angiogenesis by antagonizing survival pathways while also activating apoptotic pathways. CD36 and CD47 are both involved in the suppression of nitric oxide (NO). Advances in understanding of the molecular regulation of angiogenesis by TSP have paved the way for innovations in experimental treatment of cancers and will likely continue to offer vast avenues for discovery in other disease processes as well.
Topics: Angiogenesis Inhibitors; Antigens, CD; Antineoplastic Agents; Apoptosis; Cell Movement; Cell Proliferation; Endothelial Cells; Forecasting; Humans; Neoplasms; Neovascularization, Pathologic; Nitric Oxide; Proto-Oncogene Proteins c-fyn; Receptors, Vascular Endothelial Growth Factor; Signal Transduction; Thrombospondin 1; Thrombospondins; Vascular Endothelial Growth Factor A
PubMed: 22553494
DOI: 10.1101/cshperspect.a006627