Comparison of tenascin-C proficient versus tenascin-C deficient Mouse Embryonic Fibroblasts (MEFs)
ABSTRACT: In order to investigate what signalling pathways are turned on by tenascin-C, we generated Mouse Embryonic Fibroblasts (MEFs) deficient for tenascin-C and compared their gene expression profile to MEFs proficient for tenascin-C. Overall design: TNC-KO MEFs as well as WT MEFs in which tenascin-C was knocked-down (following stable transfection of a short hairpin RNA) were compared to WT MEFs (expressing strong endogenous levels of tenascin-C).
Project description:In order to investigate what signalling pathways are turned on by tenascin-C, we generated Mouse Embryonic Fibroblasts (MEFs) deficient for tenascin-C and compared their gene expression profile to MEFs proficient for tenascin-C. TNC-KO MEFs as well as WT MEFs in which tenascin-C was knocked-down (following stable transfection of a short hairpin RNA) were compared to WT MEFs (expressing strong endogenous levels of tenascin-C).
Project description:Tenascin C (TNC) is a matricellular glycoprotein whose expression in adult tissue is indicative of tissue remodeling. The purpose of the current study was to determine the localization of TNC in trabecular meshwork (TM) tissue and to analyze the effects of TNC on intraocular pressure (IOP).Human TM frontal sections were immunostained with anti-TNC and imaged by confocal microscopy. TNC mRNA and protein levels were quantitated in anterior segments perfused at physiological and elevated pressure. Short, hairpin RNA (shRNA) silencing lentivirus targeting full-length TNC (shTNC) was applied to anterior segment perfusion organ cultures. The IOPs and central corneal thickness (CCT) of wild-type, TNC(-/-), and tenascin X (TNX(-/-)) knockout mice were measured.TNC was distributed in the juxtacanalicular (JCT) region of adult human TM, predominantly in the basement membrane underlying the inner wall of Schlemm's canal. Application of shTNC lentivirus to human and porcine anterior segments in perfusion culture did not significantly affect outflow rate. Although TNC was upregulated in response to pressure, there was no difference in outflow rate when shTNC-silenced anterior segments were subjected to elevated pressure. Furthermore, IOPs and CCTs were not significantly different between TNC(-/-) or TNX(-/-) and wild-type mice.TNC does not appear to contribute directly to outflow resistance. However, TNC immunolocalization in the JCT of adult human eyes suggests that certain areas of the TM are being continuously remodeled with or without an IOP increase.
Project description:Mesenchymal stem cells (MSCs) are currently thought to transdifferentiate into neural lineages under specific microenvironments. Studies have reported that the tenascin family members, tenascin-C (TnC) and tenascin-R (TnR), regulate differentiation and migration, in addition to neurite outgrowth and survival in numerous types of neurons and mesenchymal progenitor cells. However, the mechanisms by which TnC and TnR affect neuronal differentiation are not well understood. In this study, we hypothesized that different forms of tenascin might regulate the neural transdifferentiation of human bone marrow-derived mesenchymal stem cells. Human MSCs were cultured in media incorporated with soluble tenascins, or on precoated tenascins. In a qualitative polymerase chain reaction analysis, adding a soluble TnC and TnR mixture to the medium significantly enhanced the expression of neuronal and glial markers, whereas no synaptic markers were expressed. Conversely, in groups of cells treated with coated TnC, hMSCs showed neurite outgrowth and synaptic marker expression. After being treated with coated TnR, hMSCs exhibited neuronal differentiation; however, it inhibited neurite outgrowth and synaptic marker expression. A combination of TnC and TnR significantly promoted hMSC differentiation in neurons or oligodendrocytes, induced neurite formation, and inhibited differentiation into astrocytes. Furthermore, the effect of the tenascin mixture showed dose-dependent effects, and a mixture ratio of 1:1 to 1:2 (TnC:TnR) provided the most obvious differentiation of neurons and oligodendrocytes. In a functional blocking study, integrin ?7 and ?9?1-blocking antibodies inhibited, respectively, 80% and 20% of mRNA expression by hMSCs in the coated tenascin mixture. In summary, the coated combination of TnC and TnR appeared to regulate neural differentiation signaling through integrin ?7 and ?9?1 in bone marrow-derived hMSCs. Our findings demonstrate novel mechanisms by which tenascin regulates neural differentiation, and enable the use of cell therapy to treat neurodegenerative diseases.
Project description:Tenascin-C (TNC) is an extracellular matrix protein expressed at high levels during lung organogenesis. Later, TNC is only transiently de novo expressed to orchestrate tissue repair in pathological situations. We previously showed that TNC inactivation affects lung development and thus evaluated here the implications on lung function in newborn/adult mice. Respiratory function parameters were measured in anesthetized and mechanically ventilated wild-type (WT) and TNC-deficient mice at 5 (P5) and 90 (P90) days of age under basal conditions, as well as following high tidal volume (HTV) ventilation. At P5, TNC-deficient mice showed an increased static compliance (Cst) and inspiratory capacity (IC) relative to WT at baseline and throughout HTV. At P90, however, Cst and IC were only elevated at baseline. Control non-ventilated newborn and adult TNC-deficient mice showed similar lung morphology, but less alpha smooth muscle actin (?-SMA) around small airways. SMA?+?cells were decreased by 50% in adult TNC-deficient lungs and collagen layer thickened around small airways. Increased surfactant protein C (SP-C) and altered TGF? and TLR4 signaling pathways were also detected. Thus, TNC inactivation-related defects during organogenesis led to persisting functional impairment in adulthood. This might be of interest in the context of pulmonary diseases with thickened airway smooth muscle layer or ventilation heterogeneity, like asthma and COPD.
Project description:Acute aortic dissection (AAD) is one of the major aortic diseases that occurs without a preceding symptom and often results in sudden death. Despite the recent advances in cardiovascular medicine, AAD remains a serious problem because its molecular pathogenesis is largely unknown. In this paper, we report our serendipitous discovery that stress-induced expression of tenascin C (TNC), a member of matricellular proteins, is the protection mechanism of aorta to prevent AAD. The aortic wall stress imposed by the aortic stiffening and the angiotensin II infusion caused the strong induction of TNC in wild type mouse aorta without gross morphological changes. While TNC knockout mice at the baseline showed no morphological, histological or biomechanical abnormalities of aorta, deletion of TNC gene rendered the aorta susceptible to AAD upon the aortic stress. The stressed TNC-null aorta showed the loss of the tensile strength due to the insufficient expression of extracellular matrix proteins and the exaggerated proinflammatory response before the onset of AAD. Therefore, TNC works as a stress-activated molecular damper both by reinforcing the tensile strength and by limiting the excessive proinflammatory response in aorta. Thus far, the molecular event that leads to the AAD development has been unclear because of the unpredictable nature of the AAD onset. This study sheds light on the previously unrecognized tissue protection mechanism that converts the potentially harmful stress response into the active reinforcement of the aorta, of which failure leads to the development of AAD. Although TNC is expressed in various tissues upon the mechanical and proinflammatory stimuli, its role has long been a mystery. Our data uncovered the adaptive role of TNC in aorta that must be resilient to the continuous hemodynamic and humoral stress for lifetime. We used periaortic application of 0.5 M CaCl2 to the infrarenal aorta or either wild type (WT) or tenascin C knockout (TNC-KO) mice to create the mouse model for stiffened aorta and infused the mice with AngII (1 µg/min/kg) for 1 week to apply the pathological stress on aorta (Ca+AngII). Mice were then killed with an overdose of pentobarbital to obtain the tissue samples. The suprarenal aortic samples, from the level of right renal artery to 10 mm above the right renal artery, and infrarenal aortic samples, from the level of left renal artery to 10 mm below the left renal artery, were collected and kept in RNAlater (Qiagen) until the extraction of total RNA using RNeasy (Qiagen). We obtained the RNA samples from 8 mice with Ca+AngII treatment and 5 mice without Ca+AngII treatment for each genotype. We pooled the RNA samples with the identical experimental condition to perform the transcriptome analysis using Mouse Genome 430 2.0 (Affymetrix). We obtained suprarenal aortic smooth muscle cells (ASMCs) from TNC-KO mice by enzymatic dispersion and cultured them in Dulbecco's modified Eagle medium (DMEM) supplemented with 10% fetal bovine serum. We cultured TNC-KO ASMCs in the presence or absence of exogenous TNC (10 µg/mL) and stimulated the cells with 10 ng/mL TNF-alpha for 24 h before obtaining total RNA using RNeasy. We used 3 independent ASMC cultures without the exogenous TNC and 4 independent cultures with the exogenous TNC. We hybridized each of the RNA samples individually to Mouse Genome 430 2.0 Array (Affymetrix).
Project description:In order to identify the effects of starvation on the MEFs wt trascriptome, we performed Affymetrix Gene-Chip hybridization experiments for the starved cells Transcriptome analysis of the starved MEFs wt cells For the analysis on the starved MEFs wt cells, total RNA was extracted; RNA extracted from MEFs wt cells grown in Normal Medium was used as control
Project description:OBJECTIVE:Expression of the de-adhesive extracellular matrix protein tenascin-C (TNC) is associated with the early postnatal development of articular cartilage which is both load-dependent and associated with chondrocyte differentiation. We assessed morphological changes in the articular cartilage of TNC deficient mice at postnatal ages of 1, 4 and 8 weeks compared to age-matched wildtype mice. RESULTS:Cartilage integrity was assessed based on hematoxylin and eosin stained-sections from the tibial bone using a modified Mankin score. Chondrocyte density and cartilage thickness were assessed morphometrically. TNC expression was localized based on immunostaining. At 8 weeks of age, the formed tangential/transitional zone of the articular cartilage was 27% thicker and the density of chondrocytes in the articular cartilage was 55% lower in wildtype than the TNC-deficient mice. TNC protein expression was associated with chondrocytes. No relevant changes were found in mice at 1 and 4 weeks of age. The findings indicate a role of tenascin-C in the post-natal maturation of the extracellular matrix in articular cartilage. This might be a compensatory mechanism to strengthen resilience against mechanical stress.
Project description:Tenascin-C (TNC) is a mechano-regulated, morphogenic, extracellular matrix protein that is associated with tissue remodeling. The physiological role of TNC remains unclear because transgenic mice engineered for a TNC deficiency, via a defect in TNC secretion, show no major pathologies. We hypothesized that TNC-deficient mice would demonstrate defects in the repair of damaged leg muscles, which would be of functional significance because this tissue is subjected to frequent cycles of mechanical damage and regeneration. TNC-deficient mice demonstrated a blunted expression of the large TNC isoform and a selective atrophy of fast-muscle fibers associated with a defective, fast myogenic expression response to a damaging mechanical challenge. Transcript profiling mapped a set of de-adhesion, angiogenesis, and wound healing regulators as TNC expression targets in striated muscle. Expression of these regulators correlated with the residual expression of a damage-related 200-kDa protein, which resembled the small TNC isoform. Somatic knockin of TNC in fast-muscle fibers confirmed the activation of a complex expression program of interstitial and slow myofiber repair by myofiber-derived TNC. The results presented here show that a TNC-orchestrated molecular pathway integrates muscle repair into the load-dependent control of the striated muscle phenotype.
Project description:Tenascin-C (TNC), a cancer-associated extracellular matrix glycoprotein, plays a pivotal role in tumor growth. However, the mechanism whereby TNC affects tumor biology remains unclear. We used microarrays to investigate change in global gene expression between tumors in wild-type (WT) mice, which express TNC, and tumors in TNC-knockout (TNKO) mice. We developed a non-TNC-producing mouse mammary tumor cell line (GLMT1). GLMT1 was inoculated in the drosal flank of WT mice and TNKO mice. After 14 days, the tumor were harvested and RNA was extracted. Subsequently, they were processed and hybridized on Affymetrix GeneChip Mouse Genome 430 2.0 Array
Project description:Oral tongue squamous cell carcinoma (OTSCC) metastasises early, especially to regional lymph nodes. There is an ongoing debate on which early stage (T1-T2N0) patients should be treated with elective neck dissection. We need prognosticators for early stage tongue cancer.Mice immunisation with human mesenchymal stromal cells resulted in production of antibodies against tenascin-C (TNC) and fibronectin (FN), which were used to stain 178?(98 early stage), oral tongue squamous cell carcinoma samples. Tenascin-C and FN expression in the stroma (negative, moderate or abundant) and tumour cells (negative or positive) were assessed. Similar staining was obtained using corresponding commercial antibodies.Expression of TNC and FN in the stroma, but not in the tumour cells, proved to be excellent prognosticators both in all stages and in early stage cases. Among early stages, when stromal TNC was negative, the 5-year survival rate was 88%. Correspondingly, when FN was negative, no cancer deaths were observed. Five-year survival rates for abundant expression of TNC and FN were 43% and 25%, respectively.Stromal TNC and, especially, FN expressions differentiate patients into low- and high-risk groups. Surgery alone of early stage primary tumours might be adequate when stromal FN is negative. Aggressive treatments should be considered when both TNC and FN are abundant.