Extracellular Matrix Structure and Interaction with Immune Cells in Adult Astrocytic Tumors.

The extracellular matrix (ECM) is a dynamic set of molecules produced by the cellular component of normal and pathological tissues of the embryo and adult. ECM acts as critical regulator in various biological processes such as differentiation, cell proliferation, angiogenesis, and immune control. The most frequent primary brain tumors are gliomas and by far the majority are adult astrocytic tumors (AATs). The prognosis for patients with these neoplasms is poor and the treatments modestly improves survival. In the literature, there is a fair number of studies concerning the composition of the ECM in AATs, while the number of studies relating the composition of the ECM with the immune regulation is smaller. Circulating ECM proteins have emerged as a promising biomarker that reflect the general immune landscape of tumor microenvironment and may represent a useful tool in assessing disease activity. Given the importance it can have for therapeutic and prognostic purposes, the aim of our study is to summarize the biological properties of ECM components and their effects on the tumor microenvironment and to provide an overview of the interactions between major ECM proteins and immune cells in AATs. As the field of immunotherapy in glioma is quickly expanding, we retain that current data together with future studies on ECM organization and functions in glioma will provide important insights into the tuning of immunotherapeutic approaches.

A novel splice-altering TNC variant (c.5247A > T, p.Gly1749Gly) in an Chinese family with autosomal dominant non-syndromic hearing loss.

BACKGROUND: This study aims to analyze the pathogenic gene in a Chinese family with non-syndromic hearing loss and identify a novel mutation site in the TNC gene. METHODS: A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis. RESULTS: The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A > T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19. CONCLUSION: This novel splice-altering variant (c.5247A > T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.

The Role of Tenascin-C in Hypertrophic Scar Formation: Insights from Cell and Animal Experiments.

Background: Hypertrophic scars (HS) are dermal diseases characterized by excessive fibroblast proliferation and collagen deposition following burns or trauma. While Tenascin-C (TNC)'s role in promoting visceral fibrosis has been established, its impact on skin tissue fibrosis remains unclear. This study aims to investigate the effects of TNC on HS. Methods: RNA sequence and IHC techniques were used to examine the upregulation of TNC gene in human hypertrophic scar tissue compared to normal tissues. Knockdown of TNC in Human skin fibroblasts (HFF-1) cells was achieved, and expression of Col1 and Col3 was evaluated using qPCR. Sirius red collagen staining assessed impact on total collagen content and ECM deposition. Effects on cell proliferation and migration were investigated through cck-8 and cell scratch experiments. Lentivirus infection was used to knock out TNC, and resulting samples were injected into ear wound of rabbits. Effects of TNC knockout on ear scar formation were measured using digital morphology, ultrasound, SEI, H&E, and Masson trichrome methods. Results: Cell experiments: downregulation of TNC decreased Col1 and Col3 expression, leading to reduced collagen production and extracellular matrix deposition. It did not affect HFF-1 cell proliferation and migration. Animal experiments: TNC knockdown promoted wound healing and reduced collagen deposition in rabbit ears. Conclusion: This study suggests that knocking down TNC inhibits collagen formation and extracellular matrix deposition, thereby inhibiting hypertrophic scar formation. Therefore, TNC can be considered a potential biomarker for HS formation and may offer promising treatment strategies for clinical management of hypertrophic scars.

Protease-activated CendR peptides targeting tenascin-C: mitigating off-target tissue accumulation.

To achieve precision and selectivity, anticancer compounds and nanoparticles (NPs) can be targeted with affinity ligands that engage with malignancy-associated molecules in the blood vessels. While tumor-penetrating C-end Rule (CendR) peptides hold promise for precision tumor delivery, C-terminally exposed CendR peptides can accumulate undesirably in non-malignant tissues expressing neuropilin-1 (NRP-1), such as the lungs. One example of such promiscuous peptides is PL3 (sequence: AGRGRLVR), a peptide that engages with NRP-1 through its C-terminal CendR element, RLVR.Here, we report the development of PL3 derivatives that bind to NRP-1 only after proteolytic processing by urokinase-type plasminogen activator (uPA), while maintaining binding to the other receptor of the peptide, the C-domain of tenascin-C (TNC-C). Through a rational design approach and screening of a uPA-treated peptide-phage library (PL3 peptide followed by four random amino acids) on the recombinant NRP-1, derivatives of the PL3 peptide capable of binding to NRP-1 only post-uPA processing were successfully identified. In vitro cleavage, binding, and internalization assays, along with in vivo biodistribution studies in orthotopic glioblastoma-bearing mice, confirmed the efficacy of two novel peptides, PL3uCendR (AGRGRLVR↓SAGGSVA) and SKLG (AGRGRLVR↓SKLG), which exhibit uPA-dependent binding to NRP-1, reducing off-target binding to healthy NRP-1-expressing tissues. Our study not only unveils novel uPA-dependent TNC-C targeting CendR peptides but also introduces a broader paradigm and establishes a technology for screening proteolytically activated tumor-penetrating peptides.

Involvement of Matricellular Proteins in Cellular Senescence: Potential Therapeutic Targets for Age-Related Diseases.

Senescence is a physiological and pathological cellular program triggered by various types of cellular stress. Senescent cells exhibit multiple characteristic changes. Among them, the characteristic flattened and enlarged morphology exhibited in senescent cells is observed regardless of the stimuli causing the senescence. Several studies have provided important insights into pro-adhesive properties of cellular senescence, suggesting that cell adhesion to the extracellular matrix (ECM), which is involved in characteristic morphological changes, may play pivotal roles in cellular senescence. Matricellular proteins, a group of structurally unrelated ECM molecules that are secreted into the extracellular environment, have the unique ability to control cell adhesion to the ECM by binding to cell adhesion receptors, including integrins. Recent reports have certified that matricellular proteins are closely involved in cellular senescence. Through this biological function, matricellular proteins are thought to play important roles in the pathogenesis of age-related diseases, including fibrosis, osteoarthritis, intervertebral disc degeneration, atherosclerosis, and cancer. This review outlines recent studies on the role of matricellular proteins in inducing cellular senescence. We highlight the role of integrin-mediated signaling in inducing cellular senescence and provide new therapeutic options for age-related diseases targeting matricellular proteins and integrins.

An investigation of the relationship between Behçet's disease and tenascin-C.

Objectives: The study aimed to investigate serum tenascin-C levels and its relationship with pathogenesis of Behçet's disease (BD) with inflammatory processes. Patients and methods: This prospective and analytical study included 34 BD patients (19 males, 15 females; mean age: 31.5±8.2 years; range, 18 to 48 years) who met the 2014 International Criteria for Behçet's Disease and had no comorbidities and 37 healthy volunteers (21 females, 16 males; mean age: 29.6±5.3 years; range, 21 to 45 years). Sex, age, age at diagnosis, clinical and laboratory data, medication use, and smoking history of the participants were recorded. Serum tenascin-C levels were measured using a commercially available tenascin-C enzyme-linked immunosorbent assay kit. Results: There was no significant difference between the groups in terms of age (p=0.262) and sex (p=0.287). Serum tenascin-C levels were significantly lower in the BD group (10,824±7,612 pg/mL) compared to the control group (27,574±14,533 pg/mL, p<0.001). In the receiver operating characteristic analysis performed for the diagnostic value of tenascin-C level in BD, the sensitivity was determined as 79.4% and the specificity as 82.5% (p<0.001). No statistically significant difference was observed in tenascin-C levels in correlation with clinical characteristics, laboratory values, medication use, and smoking in the BD group. Conclusion: In contrast to other chronic inflammatory diseases, lower levels of tenascin-C were observed in patients with BD than in the healthy individuals, which can be attributed to the absence of prolonged chronic inflammatory course in BD. The fact that tenascin-C levels are high in other rheumatic inflammatory diseases but low in BD may be useful in the differential diagnosis of BD.

Tenascin-C in patients with central nervous system infections.

BACKGROUND: The extracellular matrix protein tenascin-C has been discovered to be an important regulator of the response to tissue injury and repair in cerebrovascular diseases. This study investigated if tenascin-C is released in response to infections in the central nervous system (CNS). METHODS: Tenascin-C concentration in the cerebrospinal fluid (CSF) was measured in patients, (>18 years) with and without CNS infections, admitted to a department of infectious diseases in Denmark. CSF tenascin-C was measured on the Meso-scale platform. RESULTS: 174 patients were included of which 140 were diagnosed with a CNS infection and 34 where this was ruled out (control group). Median CSF tenascin-C levels were significantly higher among patients with bacterial meningitis (147 pg/mL), viral meningitis (33 mg/mL), viral encephalitis (39 pg/mL) and Lyme neuroborreliosis (45 pg/mL) when compared to controls (21 pg/mL). Correlations between tenascin-C and CSF markers of inflammation and age were only moderate. CONCLUSION: Levels of CSF tenascin-C are higher among patients with bacterial and viral neuroinfections, already on admission, but exhibit only a modest correlation with baseline indices of neuroinflammation. CSF tenascin-C is highest among patients with bacterial meningitis compared to the other CNS infections. Patients with unfavorable outcomes presented with higher median CSF tenascin-C than their counterparts.

Tenascin C as a novel zinc finger protein 750 target regulating the immunogenicity via DNA damage in lung squamous cell carcinoma.

Modulation of DNA damage repair in lung squamous cell carcinoma (LUSC) can result in the generation of neoantigens and heightened immunogenicity. Therefore, understanding DNA damage repair mechanisms holds significant clinical relevance for identifying targets for immunotherapy and devising therapeutic strategies. Our research has unveiled that the tumor suppressor zinc finger protein 750 (ZNF750) in LUSC binds to the promoter region of tenascin C (TNC), leading to reduced TNC expression. This modulation may impact the malignant behavior of tumor cells and is associated with patient prognosis. Additionally, single-cell RNA sequencing (scRNA-seq) of LUSC tissues has demonstrated an inverse correlation between ZNF750/TNC expression levels and immunogenicity. Manipulation of the ZNF750-TNC axis in vitro within LUSC cells has shown differential sensitivity to CD8+ cells, underscoring its pivotal role in regulating cellular immunogenicity. Further transcriptome sequencing analysis, DNA damage repair assay, and single-strand break analyses have revealed the involvement of the ZNF750-TNC axis in determining the preference for homologous recombination (HR) repair or non-homologous end joining (NHEJ) repair of DNA damage. with involvement of the Hippo/ERK signaling pathway. In summary, this study sheds light on the ZNF750-TNC axis's role in DNA damage repair regulation in LUSC, laying a groundwork for future translational research in immune cell therapy for LUSC.

Creating 3D constructs with cranial neural crest-derived cell lines using a bio-3D printer.

OBJECTIVES: The development of bio-three-dimensional (bio-3D) printers has led to significant advances in regenerative medicine. Three-dimensional constructs, including spheroids, are maintained by extracellular matrix proteins secreted by cells so that the cells can be cultured in conditions closer to the physiological environment. This study aimed to create a useful 3D construct as a model of the dentin-pulp complex. METHODS: We examined the expression patterns of extracellular matrix proteins and cell proliferation areas in a 3D construct created using O9-1 cells derived from cranial neural crest cells of mice. The 3D construct was created by sticking the spheroid cultures onto a needle array using a bio-3D printer. RESULTS: Cell proliferation areas along with characteristic expression of tenascin C and DMP1 were evaluated. The expression of tenascin C and DMP1 was significantly enhanced in the spheroids compared to that in two-dimensional cultures. Moreover, cell proliferation regions and tenascin C expression were confirmed in the outer layer of spheroids in the embryonic stem cell medium, with insignificant DMP1 expression being observed. Interestingly, in a 3D construct cultured in calcification-induction medium, DMP1 expression was promoted, and DMP1-positive cells existed in the outermost layer without overlapping with tenascin C expression. CONCLUSIONS: The extracellular matrix proteins, tenascin C and DMP1, were expressed in a polarized manner in spheroids and 3D constructs, similar to the findings in the dental papilla. Therefore, these 3D constructs show potential as artificial models for studying odontogenesis.

Tenascin-C targeting strategies in cancer.

Tenascin-C (TNC) is a matricellular and multimodular glycoprotein highly expressed under pathological conditions, especially in cancer and chronic inflammatory diseases. Since a long time TNC is considered as a promising target for diagnostic and therapeutic approaches in anti-cancer treatments and was already extensively targeted in clinical trials on cancer patients. This review provides an overview of the current most advanced strategies used for TNC detection and anti-TNC theranostic approaches including some advanced clinical strategies. We also discuss novel treatment protocols, where targeting immune modulating functions of TNC could be center stage.

Targeting myocardial inflammation: investigating the therapeutic potential of atrial natriuretic peptide in atrial fibrosis.

BACKGROUND: Atrial Fibrillation (AF), a prevalent arrhythmic condition, is intricately associated with atrial fibrosis, a major pathological contributor. Central to the development of atrial fibrosis is myocardial inflammation. This study focuses on Atrial Natriuretic Peptide (ANP) and its role in mitigating atrial fibrosis, aiming to elucidate the specific mechanisms by which ANP exerts its effects, with an emphasis on fibroblast dynamics. METHODS AND RESULTS: The study involved forty Sprague-Dawley rats, divided into four groups: control, Angiotensin II (Ang II), Ang II + ANP, and ANP only. The administration of 1 µg/kg/min Ang II was given to Ang II and Ang II + ANP groups, while both Ang II + ANP and ANP groups received 0.1 µg/kg/min ANP intravenously for a duration of 14 days. Cardiac fibroblasts were used for in vitro validation of the proposed mechanisms. The study observed that rats in the Ang II and Ang II + ANP groups showed an increase in blood pressure and a decrease in body weight, more pronounced in the Ang II group. Diastolic dysfunction, a characteristic of the Ang II group, was alleviated by ANP. Additionally, ANP significantly reduced Ang II-induced atrial fibrosis, myofibroblast proliferation, collagen overexpression, macrophage infiltration, and the elevated expression of Interleukin 6 (IL-6) and Tenascin-C (TN-C). Transcriptomic sequencing indicated enhanced PI3K/Akt signaling in the Ang II group. Furthermore, in vitro studies showed that ANP, along with the PI3K inhibitor LY294002, effectively reduced PI3K/Akt pathway activation and the expression of TN-C, collagen-I, and collagen-III, which were induced by Ang II. CONCLUSIONS: The study demonstrates ANP's potential in inhibiting myocardial inflammation and reducing atrial fibrosis. Notably, ANP's effect in countering atrial fibrosis seems to be mediated through the suppression of the Ang II-induced PI3K/Akt-Tenascin-C signaling pathway. These insights enhance our understanding of AF pathogenesis and position ANP as a potential therapeutic agent for treating atrial fibrosis.

Tenascin C activates the toll­like receptor 4/NF­κB signaling pathway to promote the development of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a globally prevalent gynecological disorder among women of childbearing age. The present study aimed to investigate the role of tenascin C (TNC) in PCOS and its potential mechanisms. Fasting blood glucose and serum insulin, the homeostasis model assessment of insulin resistance and the serum hormone levels were determined in PCOS rats. In addition, H&E staining was used for assessing pathology. In addition, the effects of TNC on oxidative stress and inflammation response in PCOS rat and cell models was assessed. Furthermore, the roles of TNC on KGN cell proliferation and apoptosis were determined employing EdU assay and flow cytometry. TLR4/NF­κB pathway­related proteins were measured using western blotting, immunofluorescence and immunohistochemistry. It was found that the mRNA and protein expression was upregulated in PCOS rats and in KGN cells induced by dihydrotestosterone (DHT). Knockdown of TNC relieved the pathological characteristics and the endocrine abnormalities of PCOS rats. Knockdown of TNC inhibited ovarian cell apoptosis, oxidative stress and inflammation in PCOS rats. Knockdown of TNC reversed the DHT­induced reduction in cell proliferation and increase in apoptosis in KGN cells. Furthermore, knockdown of TNC alleviated oxidative stress and inflammatory responses induced by DHT in KGN cells. Additionally, knockdown of TNC inhibited the toll­like receptor 4 (TLR4)/NF­κB signaling pathway in PCOS rats and DHT­treated KGN cells. In conclusion, knockdown of TNC could ameliorate PCOS in both rats and a cell model by inhibiting cell apoptosis, oxidative stress and inflammation via the suppression of the TLR4/NF­κB signaling pathway.

The Role of Tenascin-C on the Structural Plasticity of Perineuronal Nets and Synaptic Expression in the Hippocampus of Male Mice.

Neuronal plasticity is a crucial mechanism for an adapting nervous system to change. It is shown to be regulated by perineuronal nets (PNNs), the condensed forms of the extracellular matrix (ECM) around neuronal bodies. By assessing the changes in the number, intensity, and structure of PNNs, the ultrastructure of the PNN mesh, and the expression of inhibitory and excitatory synaptic inputs on these neurons, we aimed to clarify the role of an ECM glycoprotein, tenascin-C (TnC), in the dorsal hippocampus. To enhance neuronal plasticity, TnC-deficient (TnC-/-) and wild-type (TnC+/+) young adult male mice were reared in an enriched environment (EE) for 8 weeks. Deletion of TnC in TnC-/- mice showed an ultrastructural reduction of the PNN mesh and an increased inhibitory input in the dentate gyrus (DG), and an increase in the number of PNNs with a rise in the inhibitory input in the CA2 region. EE induced an increased inhibitory input in the CA2, CA3, and DG regions; in DG, the change was also followed by an increased intensity of PNNs. No changes in PNNs or synaptic expression were found in the CA1 region. We conclude that the DG and CA2 regions emerged as focal points of alterations in PNNs and synaptogenesis with EE as mediated by TnC.

Exosomal Tenascin-C primes macrophage pyroptosis amplifying aberrant inflammation during sepsis-induced acute lung injury.

Sepsis-induced acute lung injury (ALI) is a serious complication of sepsis and the predominant cause of death. Exosomes released by lung tissue cells critically influence the progression of ALI during sepsis by modulating the inflammatory microenvironment. However, the molecular mechanisms by which exosome-mediated intercellular signaling exacerbates ALI in septic infection remain undefined. Our study found increased levels of exosomal Tenascin-C (TNC) in the plasma of both patients and mice with ALI, showing a strong association with disease progression. By integrating exosomal proteomics with transcriptome sequencing and experimental validation, we elucidated that LPS induce unresolved endoplasmic reticulum stress (ERs) in alveolar epithelial cells (AECs), ultimately leading to the release of exosomal TNC through the activation of PERK-eIF2α and the transcription factor CHOP. In the sepsis mouse model with TNC knockout, we noted a marked reduction in macrophage pyroptosis. Our detailed investigations found that exosomal TNC binds to TLR4 on macrophages, resulting in an augmented production of ROS, subsequent mitochondrial damage, activation of the NF-κB signaling pathway, and induction of DNA damage response. These interconnected events culminate in macrophage pyroptosis, thereby amplifying the release of inflammatory cytokines. Our findings demonstrate that exosomal Tenascin-C, released from AECs under unresolved ER stress, exacerbates acute lung injury by intensifying sepsis-associated inflammatory responses. This research provides new insights into the complex cellular interactions underlying sepsis-induced ALI.

A single chain variable fragment antibody (Tn 64) cognate to fibronectin type III repeats promotes corneal wound healing by inhibiting fibrosis.

Corneal wound healing requires epithelial reorganization and stromal extracellular matrix (ECM) remodeling, with ECM proteins such as Tenascin C (TnC) regulating and maintaining corneal homeostasis. The N-terminal globular domain and C-terminal fibrinogen-related domains of TnC are separated by epidermal growth factor (EGF)-like repeats, and upto fifteen fibronectin type III domains (Tn fn). Overexpression of Tn fn 1-5 and its splice variants occurs in varied pathologies. We have previously used Tn64 (a single chain variable fragment antibody cognate to Tn fn 1-5) to establish roles of Tn fn 1-5 in fibrotic pathologies such as rheumatoid arthritis and posterior capsular opacification. Here, we show that Tn64 binds to Tn fn repeats 3-5 (which constitute the major site for binding of soluble fibronectin within TnC). Unlike other Tn fn domains, Tn fn 3-5 displays no inhibition of fibronectin matrix assembly. Rather, the Tn fn 3-5 construct is pro-fibrotic and elicits increased expression of fibronectin. We examined corneal epithelial as well as stromal wound healing through Tn64 binding to Tn fn 3-5, using a human corneal epithelial cell (HCEC) line, primary cultures of human corneal fibroblasts (HCFs), and an ex-vivo corneal organ culture model. Tn64 enhanced proliferation and adhesion of corneal epithelial cells, while inhibiting the migration of corneal fibroblasts and myofibroblasts. Tn64 appears to attenuate inflammation through downregulation of TNF-α, prevent corneal fibrosis by limiting fibronectin polymerization, and promote regeneration of corneal epithelia and stroma, suggesting that it could be developed as a therapeutic agent for effective anti-fibrotic corneal wound healing.

Substrate-bound and soluble domains of tenascin-C regulate differentiation, proliferation and migration of neural stem and progenitor cells.

Introduction: The lack of regenerative capacity of the central nervous system is one of the major challenges nowadays. The knowledge of guidance cues that trigger differentiation, proliferation, and migration of neural stem and progenitor cells is one key element in regenerative medicine. The extracellular matrix protein tenascin-C (Tnc) is a promising candidate to regulate cell fate due to its expression in the developing central nervous system and in the adult neural stem cell niches. Of special interest are the alternatively spliced fibronectin type III (FnIII) domains of Tnc whose combinatorial diversity could theoretically generate up to 64 isoforms in the mouse. A total of 27 isoforms have already been discovered in the developing brain, among others the domain combinations A1D, CD, and A124BCD. Methods: In the present study, these domains as well as the combination of the constitutively expressed FnIII domains 7 and 8 (78) were expressed in Chinese hamster ovary cells as pseudo-antibodies fused to the Fc-fragment of a human immunoglobulin G antibody. The fusion proteins were presented to primary mouse neural stem/progenitor cells (NSPCs) grown as neurospheres, either as coated culture substrates or as soluble additives in vitro. The influence of the domains on the differentiation, proliferation and migration of NSPCs was analyzed. Results: We observed that the domain combination A124BCD promoted the differentiation of neurons and oligodendrocytes, whereas the domain A1D supported astrocyte differentiation. The constitutively expressed domain 78 had a proliferation and migration stimulating impact. Moreover, most effects were seen only in one of the presentation modes but not in both, suggesting different effects of the Tnc domains in two- and three-dimensional cultures. Discussion: This knowledge about the different effect of the Tnc domains might be used to create artificial three-dimensional environments for cell transplantation. Hydrogels spiked with Tnc-domains might represent a promising tool in regenerative medicine.

Role of integrin ß1 and tenascin C mediate TGF-SMAD2/3 signaling in chondrogenic differentiation of BMSCs induced by type I collagen hydrogel.

Cartilage defects may lead to severe degenerative joint diseases. Tissue engineering based on type I collagen hydrogel that has chondrogenic potential is ideal for cartilage repair. However, the underlying mechanisms of chondrogenic differentiation driven by type I collagen hydrogel have not been fully clarified. Herein, we explored potential collagen receptors and chondrogenic signaling pathways through bioinformatical analysis to investigate the mechanism of collagen-induced chondrogenesis. Results showed that the super enhancer-related genes induced by collagen hydrogel were significantly enriched in the TGF-ß signaling pathway, and integrin-ß1 (ITGB1), a receptor of collagen, was highly expressed in bone marrow mesenchymal stem cells (BMSCs). Further analysis showed genes such as COL2A1 and Tenascin C (TNC) that interacted with ITGB1 were significantly enriched in extracellular matrix (ECM) structural constituents in the chondrogenic induction group. Knockdown of ITGB1 led to the downregulation of cartilage-specific genes (SOX9, ACAN, COL2A1), SMAD2 and TNC, as well as the downregulation of phosphorylation of SMAD2/3. Knockdown of TNC also resulted in the decrease of cartilage markers, ITGB1 and the SMAD2/3 phosphorylation but overexpression of TNC showed the opposite trend. Finally, in vitro and in vivo experiments confirmed the involvement of ITGB1 and TNC in collagen-mediated chondrogenic differentiation and cartilage regeneration. In summary, we demonstrated that ITGB1 was a crucial receptor for chondrogenic differentiation of BMSCs induced by collagen hydrogel. It can activate TGF-SMAD2/3 signaling, followed by impacting TNC expression, which in turn promotes the interaction of ITGB1 and TGF-SMAD2/3 signaling to enhance chondrogenesis. These may provide concernful support for cartilage tissue engineering and biomaterials development.

Tenascin-C modulates alveolarization in bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease characterized by retarded alveolarization. Tenascin-C (TN-C), an extracellular matrix glycoprotein and soluble molecule, is involved in tissue morphogenesis. In the present study, we demonstrated that the level of TN-C in lung tissues was greater in a mouse model of BPD induced by 85% oxygen. TN-C deficiency, however, impaired alveolarization in the hyperoxia-induced BPD model. In contrast, a functional TN-C blocking antibody ameliorated alveolar dysplasia in BPD-like mice. Mechanistically, hyperoxia increased the soluble TN-C (sTN-C) released from respiratory epithelial cells. On one hand, low-dose sTN-C promoted lung epithelial cell proliferation and migration, which was mediated by ICAM-1. On the other hand, high-dose sTN-C hindered the proliferation and migration of epithelial cells. Overall, this study revealed that TN-C plays a dual role in lung alveolarization and that TN-C may be a target in BPD therapy.

Association of Tenascin-C Gene Polymorphisms with Risk of Acute Coronary Syndrome in South Indian Population: A Case-Control Genetic Association Study.

Background: The extracellular matrix (ECM) glycoprotein changes are associated with the pathogenesis and complications of atherosclerosis, leading to acute coronary syndrome (ACS). Tenascin-C (TNC), an ECM protein, has been implemented in the pathogenesis, diagnosis, and prognosis of patients with cardiovascular disease. Aim: The study aimed to compare the genetic variants of the TNC gene (rs13321, rs2104772, and rs12347433) between South Indians with ACS and healthy participants. Materials and Methods: This case-control study recruited 150 ACS patients as cases and 150 healthy participants as controls. TNC genotyping was performed using TaqMan 5'-exonuclease allele discrimination assay. Serum TNC levels were measured by enzyme-linked immunosorbent assay. Results: Serum TNC levels were significantly higher in cases compared with controls. No significant difference was observed in allele and genotype frequencies of rs13321, rs2104772, and rs12347433 between cases and controls, which was confirmed by dominant, recessive, codominant, and homozygotic genetic models. The patients with heterozygous genotypes of rs13321, rs2104772, and rs12347433 had significantly lower serum TNC levels than patients with respective homozygous genotypes. Haplotype analyses revealed that the C-T-A haplotype in the block of rs13321-rs12347433-rs2104772 was associated with lower ACS risk (OR = 0.33, 95% CI: 0.15 - 0.75; p = 0.005). Also, the C-T-T and G-T-A haplotypes of the TNC gene were associated with higher and lower serum TNC levels, respectively. Conclusion: Our study demonstrated no genetic association between single nucleotide polymorphisms of the TNC gene and ACS risk; however, the C-T-A haplotype of the TNC gene might be associated with reduced ACS risk in South Indians.

Tenascin-C as a potential biomarker and therapeutic target for esophageal squamous cell carcinoma.

PURPOSE: To establish a prognostic model of esophageal squamous cell carcinoma (ESCC) patients based on tenascin-C (TNC) expression level and clinicopathological characteristics, and to explore the therapeutic potential of TNC inhibition. METHODS: The expression of TNC was detected using immunohistochemistry (IHC) in 326 ESCC specimens and 50 normal esophageal tissues. Prognostic factors were determined by Cox regression analyses and were incorporated to establish the nomogram. The effects of TNC knockdown on ESCC cells were assessed in vitro and in vivo. Transcriptome sequencing (RNA-seq) and gene set enrichment analysis (GSEA) were performed to reveal signaling pathways regulated by TNC knockdown. The therapeutic significance of TNC knockdown combined with small-molecule inhibitors on cell proliferation was examined. RESULTS: TNC protein was highly expressed in 48.77 % of ESCC tissues compared to only 2 % in normal esophageal epithelia (p < 0.001). The established nomogram model, based on TNC expression, pT stage, and lymph node metastasis, showed good performance on prognosis evaluation. More importantly, the reduction of TNC expression inhibited tumor cell proliferation and xenograft growth, and mainly down-regulated signaling pathways involved in tumor growth, hypoxia signaling transduction, metabolism, infection, etc. Knockdown of TNC enhanced the inhibitory effect of inhibitors targeting ErbB, PI3K-Akt, Ras and MAPK signaling pathways. CONCLUSION: The established nomogram may be a promising model for survival prediction in ESCC. Reducing TNC expression enhanced the sensitivity of ESCC cells to inhibitors of Epidermal Growth Factor Receptor (EGFR) and downstream signaling pathways, providing a novel combination therapy strategy.