Teneurin4 dimer structures reveal a calcium-stabilized compact conformation supporting homomeric trans-interactions.

Establishment of correct synaptic connections is a crucial step during neural circuitry formation. The Teneurin family of neuronal transmembrane proteins promotes cell-cell adhesion via homophilic and heterophilic interactions, and is required for synaptic partner matching in the visual and hippocampal systems in vertebrates. It remains unclear how individual Teneurins form macromolecular cis- and trans-synaptic protein complexes. Here, we present a 2.7 Å cryo-EM structure of the dimeric ectodomain of human Teneurin4. The structure reveals a compact conformation of the dimer, stabilized by interactions mediated by the C-rich, YD-shell, and ABD domains. A 1.5 Å crystal structure of the C-rich domain shows three conserved calcium binding sites, and thermal unfolding assays and SAXS-based rigid-body modeling demonstrate that the compactness and stability of Teneurin4 dimers are calcium-dependent. Teneurin4 dimers form a more extended conformation in conditions that lack calcium. Cellular assays reveal that the compact cis-dimer is compatible with homomeric trans-interactions. Together, these findings support a role for teneurins as a scaffold for macromolecular complex assembly and the establishment of cis- and trans-synaptic interactions to construct functional neuronal circuits.

Latent TGF-ß Activation Is a Hallmark of the Tenascin Family.

Transforming growth factor-ß (TGF-ß) isoforms are secreted as inactive complexes formed through non-covalent interactions between bioactive TGF-ß entities and their N-terminal pro-domains called latency-associated peptides (LAP). Extracellular activation of latent TGF-ß within this complex is a crucial step in the regulation of TGF-ß activity for tissue homeostasis and immune cell function. We previously showed that the matrix glycoprotein Tenascin-X (TN-X) interacted with the small latent TGF-ß complex and triggered the activation of the latent cytokine into a bioactive TGF-ß. This activation most likely occurs through a conformational change within the latent TGF-ß complex and requires the C-terminal fibrinogen-like (FBG) domain of the glycoprotein. As the FBG-like domain is highly conserved among the Tenascin family members, we hypothesized that Tenascin-C (TN-C), Tenascin-R (TN-R) and Tenascin-W (TN-W) might share with TN-X the ability to regulate TGF-ß bioavailability through their C-terminal domain. Here, we demonstrate that purified recombinant full-length Tenascins associate with the small latent TGF-ß complex through their FBG-like domains. This association promotes activation of the latent cytokine and subsequent TGF-ß cell responses in mammary epithelial cells, such as cytostasis and epithelial-to-mesenchymal transition (EMT). Considering the pleiotropic role of TGF-ß in numerous physiological and pathological contexts, our data indicate a novel common function for the Tenascin family in the regulation of tissue homeostasis under healthy and pathological conditions.

Human HINT1 Mutant Proteins that Cause Axonal Motor Neuropathy Exhibit Anomalous Interactions with Partner Proteins.

The 14 kDa histidine triad nucleotide-binding protein 1 (HINT1) is critical to maintain the normal function of motor neurons. Thus, a series of human HINT1 mutants cause autosomal recessive axonal neuropathy with neuromyotonia. HINT1 establishes a series of regulatory interactions with signaling proteins, some of which are enriched in motor neurons, such as the type 1 sigma receptor or intracellular domain (ICD) of transmembrane teneurin 1, both of which are also implicated in motor disturbances. In a previous study, we reported the capacity of HINT1 to remove the small ubiquitin-like modifier (SUMO) from a series of substrates and the influence of HINT1 mutants on this activity. We now report how human HINT1 mutations affect the interaction of HINT1 with the regulator of its SUMOylase activity, calcium-activated calmodulin, and its substrate SUMO. Moreover, HINT1 mutants exhibited anomalous interactions with G protein coupled receptors, such as the mu-opioid, and with glutamate N-methyl-D-aspartate receptors as well. Additionally, these HINT1 mutants showed impaired associations with transcriptional regulators such as the regulator of G protein signaling Z2 protein and the cleaved N-terminal ICD of teneurin 1. Thus, the altered enzymatic activity of human HINT1 mutants and their anomalous interactions with partner proteins may disrupt signaling pathways essential to the normal function of human motor neurons.

Anoikis resistance conferred by tenascin-C-derived peptide TNIIIA2 and its disruption by integrin inactivation.

Glioblastoma multiforme (GBM), the most common brain tumor in adults, has an extremely poor prognosis, which is attributed to the aggressive properties of GBM cells, such as dysregulated proliferation and disseminative migration. We recently found that peptide TNIIIA2, derived from tenascin-C (TNC), which is highly expressed in GBM, contributes to the acquisition of these aggressive properties through ß1-integrin activation. In general, cancer cells often acquire an additional malignant property that confers resistance to apoptosis due to loss of adhesion to the extracellular matrix, termed anoikis resistance. Our present results show that regulation of ß1-integrin activation also plays a key role in both the development and loss of anoikis resistance in GBM cells. Despite being derived from a GBM with an extremely poor prognosis, the human GBM cell line T98G was susceptible to anoikis but became anoikis resistant via treatment with peptide TNIIIA2, which is able to activate ß1-integrin. The TNIIIA2-conferred anoikis resistance of T98G cells was disrupted by further addition of peptide FNIII14, which has the ability to inactivate ß1-integrin. Moreover, anchorage-independent survival of GBM cells in suspension culture was abrogated by peptide FNIII14, but not by RGD and CS-1 peptides, which are antagonistic for integrins α5ß1, αvß3, and α4ß1. These results suggest that GBM cells develop anoikis resistance through activation of ß1-integrin by TNC-derived peptide TNIIIA2, which is abundantly released into the tumor microenvironment of GBM. Inactivation of ß1-integrin may provide a promising strategy to overcome the apoptosis resistance of cancer cells, including GBM.

Dynamics of the lens basement membrane capsule and its interaction with connective tissue-like extracapsular matrix proteins.

The lens, suspended in the middle of the eye by tendon-like ciliary zonule fibers and facing three different compartments of the eye, is enclosed in what has been described as the thickest basement membrane in the body. While the protein components of the capsule have been a subject of study for many years, the dynamics of capsule formation, and the region-specific relationship of its basement membrane components to one another as well as to other matrix molecules remains to be explored. Through high resolution confocal and super-resolution imaging of the lens capsule and 3D surface renderings of acquired z-stacks, our studies revealed that each of its basement membrane proteins, laminin, collagen IV, nidogen and perlecan, has unique structure, organization, and distribution specific both to the region of the lens that the capsule is located in and the position of the capsule within the eye. We provide evidence of basal membrane gradients across the depth of the capsule as well as the synthesis of distinct basement membrane lamella within the capsule. These distinctions are most prominent in the equatorial capsule zone where collagen IV and nidogen span the capsule depth, while laminin and perlecan are located in two separate lamellae located at the innermost and outermost capsule domains. We discovered that an extracapsular matrix compartment rich in the connective tissue-like matrix molecules fibronectin, tenascin-C, and fibrillin is integrated with the superficial surface of the lens capsule. Each matrix protein in this extracapsular zone also exhibits region-specific distribution with fibrils of fibrillin, the matrix protein that forms the backbone of the ciliary zonules, inserting within the laminin/perlecan lamella at the surface of the equatorial lens capsule.

Alternative splicing controls cell lineage-specific responses to endogenous innate immune triggers within the extracellular matrix.

The identification of barely more than 20,000 human genes was amongst the most surprising outcomes of the human genome project. Alternative splicing provides an essential means of expanding the proteome, enabling a single gene to encode multiple, distinct isoforms by selective inclusion or exclusion of exons from mature mRNA. However, mis-regulation of this process is associated with most human diseases. Here, we examine the impact of post-transcriptional processing on extracellular matrix function, focusing on the complex alternative splicing patterns of tenascin-C, a molecule that can exist in as many as 500 different isoforms. We demonstrate that the pro-inflammatory activity of this endogenous innate immune trigger is controlled by inclusion or exclusion of a novel immunomodulatory site located within domains AD2AD1, identifying this as a mechanism that prevents unnecessary inflammation in healthy tissues but enables rapid immune cell mobilization and activation upon tissue damage, and defining how this goes awry in autoimmune disease.

Autocrine Production of PDGF Stimulated by the Tenascin-C-Derived Peptide TNIIIA2 Induces Hyper-Proliferation in Glioblastoma Cells.

Expression level of tenascin-C is closely correlated to poor prognosis in glioblastoma patients, while the substantial role of tenascin-C responsible for aggressive progression in glioblastoma cells has not been clarified. We previously found that peptide TNIIIA2, which is derived from the tumor-associated tenascin-C variants, has the ability to promote cell adhesion by activating ß1-integrins. Our recent study demonstrated that potentiated activation of integrin α5ß1 by TNIIIA2 causes not only a dysregulated proliferation in a platelet-derived growth factor (PDGF)-dependent manner, but also disseminative migration in glioblastoma cells. Here, we show that TNIIIA2 enhances the proliferation in glioblastoma cells expressing PDGF-receptorß, even without exogenous PDGF. Mechanistically, TNIIIA2 induced upregulated expression of PDGF, which in turn stimulated the expression of tenascin-C, a parental molecule of TNIIIA2. Moreover, in glioblastoma cells and rat brain-derived fibroblasts, tenascin-C upregulated matrix metalloproteinase-2, which has the potential to release TNIIIA2 from tenascin-C. Thus, it was shown that autocrine production of PDGF triggered by TNIIIA2 functions to continuously generate a functional amount of PDGF through a positive spiral loop, which might contribute to hyper-proliferation in glioblastoma cells. TNIIIA2 also enhanced in vitro disseminative migration of glioblastoma cells via the PKCα signaling. Collectively, the tenascin-C/TNIIIA2 could be a potential therapeutic target for glioblastoma.

Aggressive Progression in Glioblastoma Cells through Potentiated Activation of Integrin α5ß1 by the Tenascin-C-Derived Peptide TNIIIA2.

Tenascin-C is a member of the matricellular protein family, and its expression level is correlated to poor prognosis in cancer, including glioblastoma, whereas its substantial role in tumor formation and malignant progression remains controversial. We reported previously that peptide TNIIIA2 derived from the cancer-associated alternative splicing domain of tenascin-C molecule has an ability to activate ß1-integrin strongly and to maintain it for a long time. Here, we demonstrate that ß1-integrin activation by TNIIIA2 causes acquisition of aggressive behavior, dysregulated proliferation, and migration, characteristic of glioblastoma cells. TNIIIA2 hyperstimulated the platelet-derived growth factor-dependent cell survival and proliferation in an anchorage-independent as well as -dependent manner in glioblastoma cells. TNIIIA2 also strongly promoted glioblastoma multiforme cell migration, which was accompanied by an epithelial-mesenchymal transition-like morphologic change on the fibronectin substrate. Notably, acquisition of these aggressive properties by TNIIIA2 in glioblastoma cells was abrogated by peptide FNIII14 that is capable of inducing inactivation in ß1-integrin activation. Moreover, FNIII14 significantly inhibited tumor growth in a mouse xenograft glioblastoma model. More importantly, FNIII14 sensitized glioblastoma cells to temozolomide via downregulation of O6-methylguanine-DNA methyltransferase expression. Consequently, FNIII14 augmented the antitumor activity of temozolomide in a mouse xenograft glioblastoma model. Taken altogether, the present study provides not only an interpretation for the critical role of tenascin-C/TNIIIA2 in aggressive behavior of glioblastoma cells, but also an important strategy for glioblastoma chemotherapy. Inhibition of the tenascin-C/ß1-integrin axis may be a therapeutic target for glioblastoma, and peptide FNIII14 may represent a new approach for glioblastoma chemotherapy. SIGNIFICANCE: These findings provide a proposal of new strategy for glioblastoma chemotherapy based on integrin inactivation.

Determinants of Tenascin-C and HIV-1 envelope binding and neutralization.

Interactions between innate antiviral factors at mucosal surfaces and HIV-1 virions contribute to the natural inefficiency of HIV-1 transmission and are a platform to inform the development of vaccine and nonvaccine strategies to block mucosal HIV-1 transmission. Tenascin-C (TNC) is a large, hexameric extracellular matrix glycoprotein identified in breast milk and genital fluids that broadly neutralizes HIV-1 via interaction with the HIV-1 Envelope (Env) variable 3 (V3) loop. In this report, we characterize the specific determinants of the interaction between TNC and the HIV-1 Env. We observed that TNC binding and neutralization of HIV-1 is dependent on the TNC fibrinogen-like globe (fbg) and fibronectin-type III (fn) domains, oligomerization, and its newly-mapped glycan structure. Moreover, we observed that TNC-mediated neutralization is also dependent on Env V3 residues 321/322 and 326/327, which surround the IGDIR motif of the V3 loop, as well the N332 glycan, which is critical to the broadly neutralizing activity of glycan-dependent V3-specific antibodies such as PGT128. Our results demonstrate a striking parallel between innate and adaptive immune mechanisms of broad HIV neutralization and provide further insight into the host protein-virus interactions responsible for the natural inefficiency of mucosal HIV-1 transmission.

The Tenascin-C-Derived Peptide VSWRAPTA Promotes Neuronal Branching Via Transcellular Activation of the Focal Adhesion Kinase (FAK) and the ERK1/2 Signaling Pathway In Vitro.

The central nervous system (CNS) of mammals has a limited regeneration capacity after traumatic events, which causes chronic functional disability. The development of biomaterials aims at providing support for the regeneration process. One strategy integrates peptides that mimic functional domains of extracellular matrix (ECM) or cell adhesion molecules with synthetic polymers designed to present growth-supporting cues to the neuronal microenvironment. Thus, small peptide sequences originating from molecules of the ECM may serve as promising bio-additives, acting as artificial matricryptins to gear cellular processes. The glycoprotein tenascin-C (Tnc) is a major constituent of the ECM of the developing brain and persists in the neurogenic regions of the adult CNS. It is a multimodular glycoprotein that comprises distinct domains with neurite growth promoting and axon growth repulsing properties. In the present study, the novel peptide motif VSWRAPTA that is encoded in the neurite growth promoting 6th fibronectin type III repeat close to the alternative splice site of Tnc was tested for its effects on neuron differentiation. When this newly synthesized biomimetic peptide was added to cultures of embryonic cortical neurons it significantly promoted the outgrowth of neurites. The neuron differentiation supporting effect was thereby associated with the trans-cellular activation of the focal adhesion kinase (FAK) and the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Cortical neurons supplemented with the Tnc peptide displayed a dose-dependent increase in neurite outgrowth that saturated at a peptide concentration of 50 µg/ml (56.4 mMol/l). The analysis of neuron morphology revealed that neurite branching rather than fiber length was stimulated by the Tnc peptide. Therefore, we predict that the analyzed peptide motif of the 6th constitutively expressed FNIII domain of the Tnc molecule might be a major contributor for neurite outgrowth and guiding events in the native CNS microenvironment. In conclusion, the Tnc-derived VSWRAPTA peptide may represent a promising tool to spike regeneration supportive microenvironments.

Tenascin-X in amniotic fluid and reproductive tissues of pregnancies complicated by infection and preterm prelabor rupture of membranes†.

Preterm prelabor rupture of membranes (PPROM), which can precede or follow intra-amniotic infection/inflammation (IAI), is a poorly understood pregnancy complication. Tenascin-X (TNX) is a connective tissue extracellular matrix protein that regulates fibrillogenesis of collagens I, III, and V. Our goal was to investigate the presence and level of soluble TNX (sTNX) in amniotic fluid (AF) and TNX expression in reproductive tissues of pregnancies complicated by PPROM and IAI. We prospectively recruited 334 women pregnant with singletons who had a clinically indicated amniocentesis for genetic karyotyping, lung maturity testing, or rule-out IAI in the presence or absence of PPROM. We quantified TNX expression in fetal membranes, myometrium, cervix, and placenta using immunological methods and qRT-PCR. In pregnancies with normal outcomes, AF sTNX levels were GA-regulated with lower levels toward term. IAI significantly upregulated AF sTNX levels independent of membrane status. AF sTNX levels inversely correlated with fetal membranes tenascin XB (TNXB) mRNA level, which was significantly downregulated by IAI. Western blotting identified characteristic ∼75 and ∼140 kDa sTNX forms in both AF and fetal membranes. Fetal membranes, placenta, and cervix constitutively express TNX with the highest abundance in the amnion. Amnion TNX richness is significantly lost in the setting of IAI. Our results suggest that fetal membranes may be a source of AF sTNX whereby protein and mRNA expression seem to be significantly impacted by inflammation independent of fetal membrane status. A more thorough understanding of TNX changes may be valuable for understanding spontaneous PPROM and to potentially develop therapeutic targets.

Prediction of folding mechanisms for Ig-like beta sandwich proteins based on inter-residue average distance statistics methods.

To understand the folding mechanism of a protein is one of the goals in bioinformatics study. Nowadays, it is enigmatic and difficult to extract folding information from amino acid sequence using standard bioinformatics techniques or even experimental protocols which can be time consuming. To overcome these problems, we aim to extract the initial folding unit for titin protein (Ig and fnIII domains) by means of inter-residue average distance statistics, Average Distance Map (ADM) and contact frequency analysis (F-value). TI I27 and TNfn3 domains are used to represent the Ig-domain and fnIII-domain, respectively. Beta-strands 2, 3, 5, and 6 are significant for the initial folding processes of TI I27. The central strands of TNfn3 were predicted as a primary folding segment. Known 3D structure and unknown 3D structure domains were investigated by structure or non-structure based multiple sequence alignment, respectively, to learn the conserved hydrophobic residues and predicted compact region relevant to evolution. Our results show good correspondence to experimental data, phi-value and protection factor from H-D exchange experiments. The significance of conserved hydrophobic residues near F-value peaks for structural stability using hydrophobic packing is confirmed. Our prediction methods once again could extract a folding mechanism only knowing the amino acid sequence.

Bioanalytical workflow for novel scaffold protein-drug conjugates: quantitation of total Centyrin protein, conjugated Centyrin and free payload for Centyrin-drug conjugate in plasma and tissue samples using liquid chromatography-tandem mass spectrometry.

AIM: Alternative scaffold proteins have emerged as novel platforms for development of therapeutic applications. One such application is in protein-drug conjugates (PDCs), which are analogous to antibody-drug conjugates. METHODOLOGY: Liquid chromatography-mass spectrometry methods for quantitation of total protein, conjugate and free payload for a PDC based on Centyrin scaffold were developed. Tryptic peptides generated from a region of the Centyrin that does not contain a conjugation site, and another that has the conjugation site with the linker-payload attached were used as surrogates of the total and conjugated Centyrin, respectively. CONCLUSION: The methods were successfully applied to analysis of samples from mice to quantify the plasma and tissue concentrations. This same workflow can potentially be applied to other PDCs and site-specific antibody-drug conjugates.

Prediction of protein flexibility using a conformationally restrained contact map.

Knowledge of protein flexibility is crucial to understanding protein function. However, probing protein flexibility by either experiment or computational simulations is a difficult process. In particular, many computational approaches to understanding protein flexibility require an experimentally determined protein structure. The Conformationally Restrained Contact Map (CoRe-CMap) approach reported here couples protein disorder predictions with protein structure predictions and only requires sequence data to predict protein flexibility. This paper reports the application of the CoRe-CMap model to predicting Lipari-Szabo order parameters of all proteins for which experimentally derived Lipari-Szabo order parameters are available in the BioMagResBank: the median root mean square deviation between a protein's predicted and experimentally derived order parameters is 0.124. Additionally, application of the CoRe-CMap model to predict Lipari-Szabo order parameters for the 10th Type III Domain in Fibronectin and a homologous domain from Tenascin demonstrates the ability of CoRe-CMap to predict functionally important differences in protein flexibility.

Structures of Teneurin adhesion receptors reveal an ancient fold for cell-cell interaction.

Teneurins are ancient cell-cell adhesion receptors that are vital for brain development and synapse organisation. They originated in early metazoan evolution through a horizontal gene transfer event when a bacterial YD-repeat toxin fused to a eukaryotic receptor. We present X-ray crystallography and cryo-EM structures of two Teneurins, revealing a ~200 kDa extracellular super-fold in which eight sub-domains form an intricate structure centred on a spiralling YD-repeat shell. An alternatively spliced loop, which is implicated in homophilic Teneurin interaction and specificity, is exposed and thus poised for interaction. The N-terminal side of the shell is 'plugged' via a fibronectin-plug domain combination, which defines a new class of YD proteins. Unexpectedly, we find that these proteins are widespread amongst modern bacteria, suggesting early metazoan receptor evolution from a distinct class of proteins, which today includes both bacterial proteins and eukaryotic Teneurins.

Mapping tenascin-C interaction with toll-like receptor 4 reveals a new subset of endogenous inflammatory triggers.

Pattern recognition underpins innate immunity; the accurate identification of danger, including infection, injury, or tumor, is key to an appropriately targeted immune response. Pathogen detection is increasingly well defined mechanistically, but the discrimination of endogenous inflammatory triggers remains unclear. Tenascin-C, a matrix protein induced upon tissue damage and expressed by tumors, activates toll-like receptor 4 (TLR4)-mediated sterile inflammation. Here we map three sites within tenascin-C that directly and cooperatively interact with TLR4. We also identify a conserved inflammatory epitope in related proteins from diverse families, and demonstrate that its presence targets molecules for TLR detection, while its absence enables escape of innate immune surveillance. These data reveal a unique molecular code that defines endogenous proteins as inflammatory stimuli by marking them for recognition by TLRs.

Fibrillin-2 and Tenascin-C bridge the age gap in lung epithelial regeneration.

Organ engineering based on native matrix scaffolds involves combining regenerative cell populations with corresponding biological matrices to form functional grafts on-demand. The extracellular matrix (ECM) that is retained following lung decellularization provides essential structure and biophysical cues for whole organ regeneration after recellularization. The unique ECM composition in the early post-natal lung, during active alveologenesis, may possess distinct signals that aid in driving cell adhesion, survival, and proliferation. We evaluated the behavior of basal epithelial stem cells (BESCs) isolated from adult human lung tissue, when cultured on acellular ECM derived from neonatal (aged < 1 week) or adult lung donors (n = 3 donors per group). A significant difference in cell proliferation and survival was found. We next performed in-depth proteomic analysis of the lung scaffolds to quantify proteins significantly enriched in the neonatal ECM, and identified the glycoproteins Fibrillin-2 (FBN-2) and Tenascin-C (TN-C) as potential mediators of the observed effect. BESCs cultured on Collagen Type IV coated plates, supplemented with FBN-2 and TN-C demonstrated significantly increased proliferation and decreased cellular senescence. No significant increase in epithelial-to-mesenchymal transition was observed. In vitro migration was also increased by FBN-2 and TN-C treatment. Decellularized lung scaffolds treated with FBN-2 and TN-C prior to re-epithelialization supported greater epithelial proliferation and tissue remodeling. BESC distribution, matrix alignment, and overall tissue morphology was improved on treated lung scaffolds, after 3 and 7 days of ex vivo lung culture. These results demonstrate that scaffold re-epithelialization is enhanced on neonatal lung ECM, and that supplementation of FBN-2 and TN-C to the native scaffold may be a valuable tool in lung tissue regeneration.

T/T homozygosity of the tenascin-C gene polymorphism rs2104772 negatively influences exercise-induced angiogenesis.

BACKGROUND: Mechanical stress, including blood pressure related factors, up-regulate expression of the pro-angiogenic extracellular matrix protein tenascin-C in skeletal muscle. We hypothesized that increased capillarization of skeletal muscle with the repeated augmentation in perfusion during endurance training is associated with blood vessel-related expression of tenascin-C and would be affected by the single-nucleotide polymorphism (SNP) rs2104772, which characterizes the non-synonymous exchange of thymidine (T)-to-adenosine (A) in the amino acid codon 1677 of tenascin-C. METHODS: Sixty-one healthy, untrained, male white participants of Swiss descent performed thirty 30-min bouts of endurance exercise on consecutive weekdays using a cycling ergometer. Genotype and training interactions were called significant at Bonferroni-corrected p-value of 5% (repeated measures ANOVA). RESULTS: Endurance training increased capillary-to-fiber-ratio (+11%), capillary density (+7%), and mitochondrial volume density (+30%) in m. vastus lateralis. Tenascin-C protein expression in this muscle was confined to arterioles and venules (80% of cases) and increased after training in A-allele carriers. Prior to training, volume densities of subsarcolemmal and myofibrillar mitochondria in m. vastus lateralis muscle were 49% and 18%, respectively, higher in A/A homozygotes relative to T-nucleotide carriers (A/T and T/T). Training specifically increased capillary-to-fiber ratio in A-nucleotide carriers but not in T/T homozygotes. Genotype specific regulation of angiogenesis was reflected by the expression response of 8 angiogenesis-associated transcripts after exercise, and confirmed by training-induced alterations of the shear stress related factors, vimentin and VEGF A. CONCLUSION: Our findings provide evidence for a negative influence of T/T homozygosity in rs2104772 on capillary remodeling with endurance exercise.

The Promoting Effect of the Extracellular Matrix Peptide TNIIIA2 Derived from Tenascin-C in Colon Cancer Cell Infiltration.

The extracellular matrix (ECM) molecule tenascin C (TNC) is known to be highly expressed under various pathological conditions such as inflammation and cancer. It has been reported that the expression of TNC is correlated with the malignant potential of cancer. In our laboratory, it was found that the peptide derived from the alternative splicing domain A2 in TNC, termed TNIIIA2, has been shown to influence a variety of cellular processes, such as survival, proliferation, migration, and differentiation. In this study, we investigated the effect of TNC/TNIIIA2 on the invasion and metastasis of colon cancer cells, Colon26-M3.1, or PMF-Ko14, using an in vitro and in vivo experimental system. The degree of cell invasion was increased by the addition of TNC and TNIIIA2 in a dose-dependent manner. The invasion by TNC and TNIIIA2 were suppressed by an MMP inhibitor or TNIIIA2-blocking antibody. In an in vivo experiment, pulmonary metastasis was promoted conspicuously by the addition of TNIIIA2. In this study, we found that colon cancer cell invasion and metastasis was accelerated by TNC/TNIIIA2 via MMP induction. This result suggests the possibility of a new strategy targeting TNC/TNIIIA2 for colon cancer.