RESUMO
Severe muscle injury causes distress and difficulty in humans. Studying the high regenerative ability of the axolotls may provide hints for the development of an effective treatment for severe injuries to muscle tissue. Here, we examined the regenerative process in response to a muscle injury in axolotls. We found that axolotls are capable of complete regeneration in response to a partial muscle resection called volumetric muscle loss (VML), which mammals cannot perfectly regenerate. We investigated the mechanisms underlying this high regenerative capacity in response to VML, focusing on the migration of muscle satellite cells and the extracellular matrix (ECM) formed during VML injury. Axolotls form tenascin-C (TN-C)-enriched ECM after VML injury. This TN-C-enriched ECM promotes the satellite cell migration. We confirmed the importance of TN-C in successful axolotl muscle regeneration by creating TN-C mutant animals. Our results suggest that the maintenance of a TN-C-enriched ECM environment after muscle injury promotes the release of muscle satellite cells and supports eventually high muscle regenerative capacity. In the future, better muscle regeneration may be achieved in mammals through the maintenance of TN-C expression.
Assuntos
Ambystoma mexicanum , Tenascina , Animais , Humanos , Tenascina/genética , Tenascina/metabolismo , Ambystoma mexicanum/metabolismo , Matriz Extracelular/metabolismo , Músculos/metabolismo , Mamíferos/metabolismo , Músculo Esquelético/metabolismoRESUMO
OBJECTIVES: This study compared the cytotoxicity, biocompatibility, and tenascin immunolabeling of a new ready-to-use hydraulic sealer (Bio-C Sealer) with MTA-Fillapex and white MTA-Angelus. MATERIALS AND METHODS: L929 fibroblasts were cultivated and exposed to undiluted and diluted material extracts. Polyethylene tubes with or without (the control) the materials were implanted into the dorsa of rats. At 7 days and 30 days, the rats were euthanized, and the specimens were prepared for analysis; inflammation and immunolabeling were measured, and statistical analysis was performed (p < 0.05). RESULTS: MTA-Fillapex exhibited greater cytotoxicity than the other materials at all time points (p < 0.05). The undiluted Bio-C Sealer exhibited greater cytocompatibility at 6 and 48 hours than white MTA-Angelus, with higher cell viability than in the control (p < 0.05). White MTA-Angelus displayed higher cell viability than the control at 24 hours, and the one-half dilution displayed similar results at both 6 and 48 hours (p < 0.05). At 7 days and 30 days, the groups exhibited moderate inflammation with thick fibrous capsules and mild inflammation with thin fibrous capsules, respectively (p > 0.05). At 7 days, moderate to strong immunolabeling was observed (p > 0.05). After 30 days, the control and MTA-Fillapex groups exhibited strong immunolabeling, the white MTA-Angelus group exhibited moderate immunolabeling (p > 0.05), and the Bio-C Sealer group exhibited low-to-moderate immunolabeling, differing significantly from the control (p < 0.05). CONCLUSIONS: Bio-C Sealer and white MTA-Angelus exhibited greater cytocompatibility than MTA-Fillapex; all materials displayed adequate biocompatibility and induced tenascin immunolabeling.
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The purpose of this study was to compare the immunohistochemical expression of tenascin-C (Tn-C) regarding clinicopathological variables and its association with the clinical behavior of central giant cell lesions (CGCLs). Forty-eight paraffin-embedded samples of CGCLs were selected. Based on clinical and radiographic features, the lesions were classified as aggressive (A-CGCLs) and non-aggressive (NA-CGCLs) subtypes. Histological assessment included the microvessel count (MVC), multinucleated giant cell (MGC) count, and the proportion of tissue area involved by mononuclear stromal cells/interstitial fibrosis. Immunoreactivity, immunolocalization, and distribution patterns of Tn-C were studied immunohistochemically. The association between Tn-C expression and clinicopathological characteristics was analyzed separately and adjusted for confounders using logistic regression models. A significantly greater proportion of cases with moderate-to-intense, intracellular, and diffuse staining of Tn-C was observed in A-CGCLs. CGCLs with a size ≥3.3 cm, fast growth, cortical disruption, high MVC/MGC counts, and low interstitial fibrosis showed a significantly greater frequency of moderate-to-intense, intracellular, and diffuse staining. Logistic regression analysis indicated a strong/independent association of these three immunohistochemical parameters with the aggressiveness of lesions. These data appear to suggest a possible role for Tn-C in the etiopathogenesis of CGCLs of the jaws, where its upregulation might favor the destructive behavior of A-CGCLs.
Assuntos
Regulação da Expressão Gênica , Células Gigantes/patologia , Doenças Maxilomandibulares/metabolismo , Doenças Maxilomandibulares/patologia , Tenascina/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-IdadeRESUMO
Aims: The aim of this study was to evaluate the biocompatibility of resinous root canal sealers: Sealer 26, AH plus, and SK Seal Root Canal Sealer in the subcutaneous tissue of rats. Subjects and Methods: Twenty-four Wistar rats received polyethylene tubes containing the sealers and empty tubes as control (n = 6). After 7, 15, 30, and 60 days, animals were killed and polyethylene tubes were removed with the surrounding tissues. The specimens were embedded in paraffin, processed for hematoxylin-eosin and immunohistochemistry assessed for fibronectin (FN) and tenascin (TN). Statistical Analysis Used: Data were tabulated and analyzed via Kruskal-Wallis and Dunn's test (P < 0.05). Results: All groups induced a moderate inflammatory reaction after 7 and 15 days (P > 0.05); after 30 days, a mild inflammatory infiltrate was observed in control groups, and moderate in sealers groups (P > 0.05); all groups showed mild inflammatory infiltrate at 60 days (P > 0.05). Overall, the fibrous capsule was considered thick only on the 7th day and became thin over time. All groups had expression for FN and TN in all analyzed periods, with high immunolabeling in sealers groups when comparing with the control group (P < 0.05). Conclusion: All sealers demonstrated biocompatibility and induced FN and TN expression.
RESUMO
Breast cancer is one of the most frequently diagnosed cancers and the leading cause of cancer-related deaths in women worldwide, whereby mortality is largely attributable to the development of distant metastasis. Caveolin-1 (CAV1) is a multifunctional membrane protein that is typically upregulated in the final stages of cancer and promotes migration and invasion of tumor cells. Elevated levels of CAV1 have been detected in extracellular vesicles (EVs) from advanced cancer patients. EVs are lipid enclosed vesicular structures that contain bioactive proteins, DNA and RNAs, which can be transferred to other cells and promote metastasis. Therefore, we hypothesized that CAV1 containing EVs released from breast cancer cells may enhance migration and invasion of recipient cells. EVs were purified from conditioned media of MDA-MB-231 wild-type (WT), MDA-MB-231 (shCAV1; possessing the plasmid pLKO.1 encoding a 'small hairpin' directed against CAV1) and MDA-MB-231 (shC) short hairpin control cells. Nanoparticle tracking analysis revealed an average particle size of 40-350 nm for all preparations. As anticipated, CAV1 was detected in MDA-MB-231 WT and shC EVs, but not in MDA-MB-231 (shCAV1) EVs. Mass spectrometry analysis revealed the presence of specific cell adhesion-related proteins, such as Cyr61, tenascin (TNC) and S100A9 only in WT and shC, but not in shCAV1 EVs. Importantly, EVs containing CAV1 promoted migration and invasion of cells lacking CAV1. We conclude that the presence of CAV1 in EVs from metastatic breast cancer cells is associated with enhanced migration and invasiveness of recipient cells in vitro, suggesting that intercellular communication promoted by EVs containing CAV1 will likely favor metastasis in vivo.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Caveolina 1/genética , Adesão Celular/efeitos dos fármacos , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Caveolina 1/química , Comunicação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Vesículas Extracelulares/química , Feminino , Humanos , Células MCF-7 , Metástase NeoplásicaRESUMO
AIM: The aim was to compare the immunoexpression of extracellular matrix proteins in squamous cell carcinomas of tongue (SCCTo) and lower lip (SCCLi). METHODS: Eleven SCCTo and 11 SCCLi were selected and examined according to Bryne's method (1998). For immunohistochemical study utilized antibodies to fibronectin, tenascin and type I collagen. Histopathologic and immunohistochemical analysis were performed on the tumor invasive front. RESULTS: All SCCTo were classified in high score malignant grade and all SCCLi in lower score. Fibronectin showed strong immunorreactivity in the peritumoral basement membrane (BM) in 91% of SCCTo and all cases of SCCLi, while in the tumor stroma (TS) all cases of SCCTo and SCCLi had strong intensity. Tenascin had strong expression in BM of 91% cases of SCCTo and 63.4% of SCCLi and in TS had strong expression in 91% cases of SCCTo and 54.6% of SCCLi. Type I collagen demonstrated weak immunoreactivity in the TS of 72.7% cases of SCCTo and 63.4% of SCCLi. CONCLUSION: These results may suggest that the strong expression of fibronectin and tenascin proteins and the weak expression of type I collagen could play a role in the invasive process of oral SCC (AU)
Assuntos
Colágeno Tipo I , Fibronectinas , Imuno-Histoquímica , Neoplasias Bucais , TenascinaRESUMO
Objetivo: Avaliar a resposta tecidual e a capacidade de biomineralização dos materiais endodônticos SK Seal Root Canal Sealer (SK Seal), Sealer 26® e AH plus® em tecido subcutâneo de ratos. Material e Métodos: Vinte e quatro ratos Wistar (n=6) receberam implantes subcutâneo contendo os cimentos e um tubo vazio como controle. Após 7, 15, 30 e 60 dias, os animais foram eutanasiados e os tubos de polietileno foram removidos junto com o tecido circunjacente. Em seguida, os espécimes foram processados para análise em Hematoxilina-Eosina, von Kossa, luz polarizada e imunoistoquímica para fibronectina (FN) e tenascina (TN). Os dados foram tabulados e analisados através do teste de Kruskal-Wallis e Dunn (p<0,05). Resultados: Todos os materiais testados induziram uma reação inflamatória moderada aos 7 e 15 dias (p> 0,05). Não foram observadas diferenças entre os grupos após 30 ou 60 dias (p> 0,05). A cápsula fibrosa foi considerada espessa aos 7 dias, tornando-se fina no final do experimento. Todos os grupos apresentaram marcadores positivos para FN e TN em todos os tempos de análise, com maior imunomarcação para os cimentos em comparação ao grupo controle (p <0,05). Os cimentos não apresentaram von Kossa positiva ou estruturas birrefringentes à luz polarizada. Conclusão: Todos os cimentos testados apresentaram biocompatibilidade, porém não estimularam a mineralização(AU)
Aim: The aim of this study was to evaluate biocompatibility and biomineralization of the endodontic materials SK Seal Root Canal Sealer (SK Seal), Sealer 26® and AH plus® in subcutaneous tissue of rats. Methodology: Twenty-four Wistar rats (n=6) received subcutaneous implants containing the test sealers, and an empty tube as control. After 7, 15, 30 and 60 days, the animals were killed and polyethylene tubes were removed with the surrounding tissues. The pieces were processed for Hematoxylin-Eosin, von Kossa, polarized light and immunohistochemical analysis for fibronectin (FN) and tenascin (TN). Data were tabulated and analyzed via Kruskal-Wallis and Dunn's test (p<0,05). Results: All tested materials induced a moderate infammatory reaction after 7 and 15 days. (p>0,05). No difference was observed among groups after days 30 or 60 days (p>0.05). The fibrous capsule was considered thick on the 7th day, and classified as thin at the end of the experiment. All groups presented positive markers for FN and TN in all analyzed time, with higher immunolabeling to sealers in comparison with the control group (p<0,05). The sealers did not present von Kossa positive or birefringent structures to polarized light. Conclusion: All tested sealers demonstrated biocompatibility, but did not stimulate the mineralization(AU)
Assuntos
Animais , Ratos , Inflamação , Obturação do Canal Radicular , Calcificação Fisiológica , Ratos Wistar , Receptores de Fibronectina , TenascinaRESUMO
Extracellular matrix (ECM) molecules are pivotal for central nervous system (CNS) development, facilitating cell migration, axonal growth, myelination, dendritic spine formation, and synaptic plasticity, among other processes. During axon guidance, the ECM not only acts as a permissive or non-permissive substrate for navigating axons, but also modulates the effects of classical guidance cues, such as netrin or Eph/ephrin family members. Despite being highly important, little is known about the expression of ECM molecules during CNS development. Therefore, this study assessed the molecular expression patterns of tenascin, HNK-1, laminin, fibronectin, perlecan, decorin, and osteopontin along chick embryo prosomere 1 during posterior commissure development. The posterior commissure is the first transversal axonal tract of the embryonic vertebrate brain. Located in the dorso-caudal portion of prosomere 1, posterior commissure axons primarily arise from the neurons of basal pretectal nuclei that run dorsally to the roof plate midline, where some turn toward the ipsilateral side. Expressional analysis of ECM molecules in this area these revealed to be highly arranged, and molecule interactions with axon fascicles suggested involvement in processes other than structural support. In particular, tenascin and the HNK-1 epitope extended in ventro-dorsal columns and enclosed axons during navigation to the roof plate. Laminin and osteopontin were expressed in the midline, very close to axons that at this point must decide between extending to the contralateral side or turning to the ipsilateral side. Finally, fibronectin, decorin, and perlecan appeared unrelated to axonal pathfinding in this region and were instead restricted to the external limiting membrane. In summary, the present report provides evidence for an intricate expression of different extracellular molecules that may cooperate in guiding posterior commissure axons.
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Ehlers-Danlos syndrome is a rare clinical condition caused by a genetic change that results in the formation of structurally or functionally altered collagen. The clinical manifestations are varied, being the most obvious skin hypermotility and increased joint flexibility, although other systems - such as cardiovascular, respiratory and neurological - may also be affected. This paper presents the report of a patient who sought medical attention with complaints of atypical chest pain. Clinical evaluation enabled hypothetical diagnosis of hypertrophic obstructive cardiomyopathy and Ehlers-Danlos syndrome. Initial electrocardiogram, echocardiogram and 24 hours holter allowed the confirmation of the first hypothesis. A skin biopsy performed later associated clinical data and confirmed the second hypothesis.
.Assuntos
Idoso , Feminino , Humanos , Cardiomiopatia Hipertrófica/fisiopatologia , Síndrome de Ehlers-Danlos/fisiopatologia , Biópsia , Cardiomiopatia Hipertrófica , Colágeno/fisiologia , Eletrocardiografia Ambulatorial , Síndrome de Ehlers-Danlos/patologia , Pele/patologiaRESUMO
Seizures have been shown to upregulate the expression of numerous extracellular matrix molecules. Tenascin C (TNC) is an extracellular matrix protein involved in several physiological roles and in pathological conditions. Though TNC upregulation has been described after excitotoxins injection, to date there is no research work on the signal transduction pathway(s) participating in TNC protein overproduction. The aim of this study was to evaluate the role of TGF-ß signaling pathway on TNC upregulation. In this study, we used male rats, which were injected with saline or pilocarpine to induce status epilepticus (SE) and killed 24h, 3 and 7 days after pilocarpine administration. For evaluating biochemical changes, we measured protein content of TNC, TGF-ß1 and phospho-Smad2/3 for localization of TNC in coronal brain hippocampus at 24h, 3 and 7 days after pilocarpine-caused SE. We found a significant increase of TNC protein content in hippocampal homogenates after 1, 3, and 7 days of pilocarpine-caused SE, together with an enhancement of TNC immunoreactivity in several hippocampal layers and the dentate gyrus field where more dramatic changes occurred. We also observed a significant enhancement of protein content of both the TGF-ß1 and the critical downstream transduction effector phospho-Smad2/3 throughout the chronic exposure. Interestingly, animals injected with SB-431542, a TGF-ß-type I receptor inhibitor, decreased TNC content in cytosolic fraction and diminished phospho-Smad2/3 content in both cytoplasmic and nuclear fraction compared with pilocarpine vehicle-injected. These findings suggest the participation of TGF-ß signaling pathway on upregulation of TNC which in turn support the idea that misregulation of this signaling pathway produces changes that may contribute to disease.