934 resultados para Cell Signaling


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Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

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Bone Morphogenetic Proteins (BMPs) are multifunctional secreted cytokines, which belong to the TGF-beta superfamily. These glycoproteins act as a disulfide-linked homo- or heterodimers, being potent regulators of bone and cartilage formation and repair, cell proliferation during embryonic development and bone homeostasis in the adult. BMPs are promising molecules for tissue engineering and bone therapy. The present review discusses this family of proteins, their structure and biological function, their therapeutic applications and drawbacks, their effects on mesenchymal stem cells differentiation, and the cell signaling pathways involved in this process. (C) 2014 Published by Elsevier Inc.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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p38 mitogen-activated protein kinases (MAPKs) are critical for innate immune signaling and subsequent cytokine expression in periodontal inflammation and bone destruction. In fact, previous studies show that systemic p38 MAPK inhibitors block periodontal disease progression. However, development of p38 MAPK inhibitors with favorable toxicological profiles is difficult. Here, we report our findings regarding the contribution of the downstream p38 MAPK substrate, mitogen-activated protein kinase-activated protein kinase 2 (MK2 or MAPKAPK-2), in immune response modulation in an experimental model of pathogen-derived lipopolysaccharide (LPS)-induced periodontal bone loss. To determine whether small interfering RNA (siRNA) technology has intraoral applications, we initially validated MK2 siRNA specificity. Then, gingival tissue surrounding maxillary molars of rats was injected with MK2 siRNA or scrambled siRNA at the palatal regions of bone loss. Intraoral tissues treated with MK2 siRNA had significantly less MK2 mRNA expression compared with scrambled siRNA-treated tissues. MK2 siRNA delivery arrested LPS-induced inflammatory bone loss, decreased inflammatory infiltrate, and decreased osteoclastogenesis. This proof-of-concept study suggests a novel target using an intraoral RNA interference strategy to control periodontal inflammation.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Substances that mimic endogenous hormones may alter the cell signaling that govern prostate development and predispose it to developing lesions in adult and senile life. Bisphenol A is able to mimic estrogens, and studies have demonstrated that low levels of exposure to this compound have caused alterations during prostate development. The aim of this study was to describe the prostate development in both male and female neonatal gerbils in normal conditions and under exposure to BPA during intrauterine life, and also to analyze whether the effects of intrauterine exposure to BPA remain in adulthood. Morphological, stereological, three-dimensional reconstruction, and immunohistochemical methods were employed. The results demonstrated that in 1-day-old normal gerbils, the female paraurethral glands and the male ventral lobe are morphologically similar, although its tissue components-epithelial buds (EB), periurethral mesenchyme (PeM), paraurethral mesenchyme (PaM) or ventral mesenchymal pad (VMP), and smooth muscle (SM)-have presented different immunolabeling pattern for androgen receptor (AR), and for proliferating cell nuclear antigen (PCNA). Moreover, we observed a differential response of male and female prostate to intrauterine BPA exposure. In 1-day-old males, the intrauterine exposure to BPA caused a decrease of AR-positive cells in the PeM and SM, and a decrease of the proliferative status in the EB. In contrast, no morphological alterations were observed in ventral prostate of adult males. In 1-day-old females, BPA exposure promoted an increase of estrogen receptor alpha (ERα) positive cells in PeM and PaM, a decrease of AR-positive cells in EB and PeM, besides a reduction of cell proliferation in EB. Additionally, the adult female prostate of BPA-exposed animals presented an increase of AR- and PCNA-positive cells. These results suggest that the prostate of female gerbils were more susceptible to the intrauterine BPA effects, since they became more proliferative in adult life. © 2015 Wiley Periodicals, Inc. Environ Toxicol, 2015.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The mechanisms linking obesity to kidney damage are unknown. AGEs are responsible for renal damage in obese individuals. The receptor AGEs (RAGE) contributes to nuclear transcription factors that result in the production of proinflammatory cytokines and this seems to contribute to the development of renal disease. Thus, intervention with antioxidant can have an important effect in the prevention and treatment of pro-oxidant and pro-inflammatory state in the kidneys resulting from obesity.

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OBJECTIVES: The phosphatidylinositol 3-kinase/AKT axis is an important cell-signaling pathway that mediates cell proliferation and survival, two biological processes that regulate malignant cell growth. The phosphatidylinositol 3-kinase CA gene encodes the p110 alpha subunit of the phosphatidylinositol 3-kinase protein. There are phosphatidylinositol 3-kinase CA mutations in several types of human tumors, and they are frequently observed in breast cancer. However, these mutations have not been investigated in Brazilian breast cancer patients. METHODS: PCR-SSCP and direct DNA sequencing were performed to identify phosphatidylinositol 3-kinaseCA exon 9 and exon 20 mutations in 86 patients with sporadic breast cancer. The relationships between PIK3CA mutations and patient clinicopathological characteristics and survival were analyzed. The presence of the TP53 mutation was also examined. RESULTS: Twenty-three (27%) of the 86 primary breast tumors contained PIK3CA mutations. In exons 9 and 20, we identified the hotspot mutations E542K, E545K, and H1047R, and we identified two new missense mutations (I1022V and L1028S) and one nonsense (R992X) mutation. Phosphatidylinositol 3-kinase CA exon 20 mutations were associated with poor overall survival and TP53 gene mutations. CONCLUSIONS: Phosphatidylinositol 3-kinase CA mutations are common in tumors in Brazilian breast cancer patients, and phosphatidylinositol 3-kinase CA and TP53 mutations are not mutually exclusive. Phosphatidylinositol 3-kinase CA exon 20 mutations are associated with poor survival, and they may be useful biomarkers for identifying breast cancer patients with aggressive tumors and for predicting the response to treatment with PI3K pathway inhibitors.

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In the last decade, molecular biology has contributed to define some of the cellular events that trigger skeletal muscle hypertrophy. Recent evidence shows that insulin like growth factor 1/phosphatidyl inositol 3-kinase/protein kinase B (IGF-1/PI3K/Akt) signaling is not the main pathway towards load-induced skeletal muscle hypertrophy. During load-induced skeletal muscle hypertrophy process, activation of mTORC1 does not require classical growth factor signaling. One potential mechanism that would activate mTORC1 is increased synthesis of phosphatidic acid (PA). Despite the huge progress in this field, it is still early to affirm which molecular event induces hypertrophy in response to mechanical overload. Until now, it seems that mTORC1 is the key regulator of load-induced skeletal muscle hypertrophy. On the other hand, how mTORC1 is activated by PA is unclear, and therefore these mechanisms have to be determined in the following years. The understanding of these molecular events may result in promising therapies for the treatment of muscle-wasting diseases. For now, the best approach is a good regime of resistance exercise training. The objective of this point-of-view paper is to highlight mechanotransduction events, with focus on the mechanisms of mTORC1 and PA activation, and the role of IGF-1 on hypertrophy process.

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Cell therapy is a therapeutic strategy used to replace or repair damaged tissue. The epithelium transplantation of cultivated keratinocytes has been applied to several modalities of reconstruction, like oral, urethra and ocular surface. Life and death signals work coordinately to ensure cellular quality control and the viability of an organism. The aim of this study is to verify that culture conditions did not induce genetic mutations through the analysis of the key genes: pAKT, Pten, p53 and MDM2 and investigate the presence of the related proteins in human oral keratinocytes obtained by primary culture and in vitro cultivated. Formalin fixed and paraffin embedded tissues from the oral cavity were utilized as control for normal expression of the related markers and two oral squamous cell carcinoma cell lines provided the expression pattern of the proposed markers in the event of cellular transformation. Akt, PTEN, p53 and MDM2 immunohistochemistry and Western-Blotting analyzes were performed. The results showed the expression levels and intracellular localizations of the four proteins evaluated. These analyzes confirmed that the produced in vitro epithelium is bio-compatible for its utilization as reconstruction and reparatory tissue, however further analyses and additional research on other biomarkers should be performed to analyse the long term engraftment of transplantable primary culture of oral keratinocytes and the long term resistance to cellular transformation.

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Abstract Background The ongoing efforts to sequence the honey bee genome require additional initiatives to define its transcriptome. Towards this end, we employed the Open Reading frame ESTs (ORESTES) strategy to generate profiles for the life cycle of Apis mellifera workers. Results Of the 5,021 ORESTES, 35.2% matched with previously deposited Apis ESTs. The analysis of the remaining sequences defined a set of putative orthologs whose majority had their best-match hits with Anopheles and Drosophila genes. CAP3 assembly of the Apis ORESTES with the already existing 15,500 Apis ESTs generated 3,408 contigs. BLASTX comparison of these contigs with protein sets of organisms representing distinct phylogenetic clades revealed a total of 1,629 contigs that Apis mellifera shares with different taxa. Most (41%) represent genes that are in common to all taxa, another 21% are shared between metazoans (Bilateria), and 16% are shared only within the Insecta clade. A set of 23 putative genes presented a best match with human genes, many of which encode factors related to cell signaling/signal transduction. 1,779 contigs (52%) did not match any known sequence. Applying a correction factor deduced from a parallel analysis performed with Drosophila melanogaster ORESTES, we estimate that approximately half of these no-match ESTs contigs (22%) should represent Apis-specific genes. Conclusions The versatile and cost-efficient ORESTES approach produced minilibraries for honey bee life cycle stages. Such information on central gene regions contributes to genome annotation and also lends itself to cross-transcriptome comparisons to reveal evolutionary trends in insect genomes.