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Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) control antral follicular growth by regulating several processes, such as the synthesis of hormones and signaling molecules, proliferation, survival, apoptosis, luteinization, and ovulation. To exert these effects, gonadotropins bind to their respective Gs protein-coupled receptors, activating the protein kinase A (PKA) pathway or recruiting Gq proteins to activate protein kinase C (PKC) signaling. Although the action mechanism of FSH and LH is clear, recently, it has been shown that both gonadotropins promote the synthesis of sphingosine-1-phosphate (S1P) in granulosa and theca cells through the activation of sphingosine kinase 1. Moreover, the inhibition of SPHKs reduces S1P synthesis, cell viability, and the proliferation of follicular cells in response to gonadotropins, and the addition of S1P to the culture medium increases the proliferation of granulosa and theca cells without apparent effects on sexual steroid synthesis. Therefore, we consider that S1P is a crucial signaling molecule that complements the canonical gonadotropin pathway to promote the proliferation and viability of granulosa and theca cells.

Assuntos

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Inflammatory Bowel Diseases had their first peak in incidence in countries in North America, Europe, and Oceania and are currently experiencing a new acceleration in incidence, especially in Latin America and Asia. Despite technological advances, 90 years after the development of the first molecule for the treatment of IBD, we still do not have drugs that promote disease remission in a generalized way. We carried out a narrative review on therapeutic advances in the treatment of IBD, the mechanisms of action, and the challenges facing the therapeutic goals in the treatment of IBD. Salicylates are still used in the treatment of Ulcerative Colitis. Corticosteroids have an indication restricted to the period of therapeutic induction due to frequent adverse events, while technologies with less systemic action have been developed. Most immunomodulators showed a late onset of action, requiring a differentiated initial strategy to control the disease. New therapeutic perspectives emerged with biological therapy, initially with anti-TNF, followed by anti-integrins and anti-interleukins. Despite the different mechanisms of action, there are similarities between the general rates of effectiveness. These similar results were also evidenced in JAK inhibitors and S1p modulators, the last therapeutic classes approved for the treatment of IBD.

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Sphingolipid-1-phosphate (S1P) signaling through the activation S1P receptors (S1PRs) plays critical roles in cellular events in the brain. Aberrant S1P metabolism has been identified in the brains of Alzheimer's disease (AD) patients. Our recent studies have shown that treatment with fingolimod, an analog of sphingosine, provides neuroprotective effects in five familiar Alzheimer disease (5xFAD) transgenic mice, resulting in the reduction of amyloid-ß (Aß) neurotoxicity, inhibition of activation of microglia and astrocytes, increased hippocampal neurogenesis, and improved learning and memory. However, the pathways by which dysfunctional S1P and S1PR signaling may associate with the development of AD-like pathology remain unknown. In this study, we investigated the alteration of signaling of S1P/S1P receptor 1 (S1PR1), the most abundant S1PR subtype in the brain, in the cortex of 5xFAD transgenic mice at 3, 8, and 14 months of age. Compared to non-transgenic wildtype (WT) littermates, we found significant decreased levels of sphingosine kinases (SphKs), increased S1P lyase (S1PL), and increased S1PR1 in 8- and 14-month-old, but not in 3-month-old 5xFAD mice. Furthermore, we detected increased activation of the S1PR1 downstream pathway of Akt/mTor/Tau signaling in aging 5xFAD mice. Treatment with fingolimod from 1 to 8 months of age reversed the levels of SphKs, S1PL, and furthermore, those of S1PR1 and its downstream pathway of Akt/mTor/Tau signaling. Together the data reveal that dysregulation of S1P and S1PR signaling may associate with the development of AD-like pathology through Akt/mTor/Tau signaling.

Assuntos

Assuntos

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The fibrotic process could be easily defined as a pathological excess of extracellular matrix deposition, leading to disruption of tissue architecture and eventually loss of function; however, this process involves a complex network of several signal transduction pathways. Virtually almost all organs could be affected by fibrosis, the most affected are the liver, lung, skin, kidney, heart, and eyes; in all of them, the transforming growth factor-beta (TGF-ß) has a central role. The canonical and non-canonical signal pathways of TGF-ß impact the fibrotic process at the cellular and molecular levels, inducing the epithelial-mesenchymal transition (EMT) and the induction of profibrotic gene expression with the consequent increase in proteins such as alpha-smooth actin (α-SMA), fibronectin, collagen, and other extracellular matrix proteins. Recently, it has been reported that some molecules that have not been typically associated with the fibrotic process, such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4), mammalian target of rapamycin (mTOR), histone deacetylases (HDAC), and sphingosine-1 phosphate (S1P); are critical in its development. In this review, we describe and discuss the role of these new players of fibrosis and the convergence with TGF-ß signaling pathways, unveiling new insights into the panorama of fibrosis that could be useful for future therapeutic targets.

Assuntos

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Variants in MBTPS1 (membrane-bound transcription factor peptidase, site 1) encoding the protein convertase site-1 protease (S1P) were recently reported in a single individual with skeletal dysplasia and elevated plasma lysosomal enzymes. Here, we report the second individual with this newly described autosomal recessive spondyloepiphyseal dysplasia (OMIM #618392), presenting severe growth retardation, cataract and dysmorphic features, mainly retromicrognathia. Epilepsy and craniosynostosis were novel findings in our proband. She was found to be homozygous for a novel nonsense variant p.Trp983Ter in MBTPS1. In addition, she had normal levels of lysosomal enzyme activity in leukocytes but elevated levels in plasma. Our description confirms the existence of this new skeletal dysplasia and expands the phenotype and genotype of the disease.

Assuntos

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PURPOSE: Sphingosine 1 phosphate (S1P), S1P receptors (S1PRs) and their signaling pathways play an important role in the fate of cancer cells. The expression pattern of S1PR subtypes (S1PR1-S1PR5) may alter in cancer development stages, depending on the origin and the pathologic features of tumors. The present study aimed to examine the relationship between plasma S1P levels and the expression of S1PR subtypes in bladder tumors. METHODS/PATIENTS: These changes were evaluated in terms of the pathologic grades and stages of human bladder cancer samples. For this, tumor biopsies from 41 new bladder cancer patients as well as 26 normal-looking bladder tissues were collected and processed for immunohistochemistry (IHC) and quantitative real-time RT-PCR of S1PR subtypes. Plasma S1P level was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: The results show that tissue S1PR1, S1PR2 and S1PR3 are over-expressed in all tumors regardless of their pathological grade (~ 3, ~ 6 and ~ 104 folds, respectively). These results were corroborated by IHC data showing accumulation of S1PR subtypes 1 and 2 in the tissues. Plasma S1P in the plasma samples from patients was in the range of control samples (Controls; 256 ± 47; patients, 270 ± 41). CONCLUSIONS: Overexpression of S1PR1, S1PR2 and S1PR3 in bladder tumor biopsies which were corroborated with the pathological grades and stages may suggest that S1PR profile in tumor biopsies is a promising marker in the diagnosis of bladder carcinoma.

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Sphingosine 1-phosphate (S1P) and FTY720-phosphate (FTYp) increased intracellular calcium in cells expressing S1P1 mCherry-tagged receptors; the synthetic agonist was considerably less potent. Activation of protein kinase C by phorbol myristate acetate (PMA) blocked these effects. The three agents induced receptor phosphorylation and internalization, with the action of FTYp being more intense. S1P1 receptor-Rab protein (GFP-tagged) interaction was studied using FRET. The three agents were able to induce S1P1 receptor-Rab5 interaction, although with different time courses. S1P1 receptor-Rab9 interaction was mainly increased by the phorbol ester, whereas S1P1 receptor-Rab7 interaction was only increased by FTYp and after a 30-min incubation. These actions were not observed using dominant negative (GDP-bound) Rab protein mutants. The data suggested that the three agents induce interaction with early endosomes, but that the natural agonist induced rapid receptor recycling, whereas activation of protein kinase C favored interaction with late endosome and slow recycling and FTYp triggered receptor interaction with vesicles associated with proteasomal/lysosomal degradation. The ability of bisindolylmaleimide I and paroxetine to block some of these actions suggested the activation of protein kinase C was associated mainly with the action of PMA, whereas G protein-coupled receptor kinase (GRK) 2 (GRK2) was involved in the action of the three agents.

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Sphingolipid metabolism pathway is essential in membrane homeostasis, and its dysfunction has been associated with favorable tumor microenvironment, disease progression, and chemotherapy resistance. Its major components have key functions on survival and proliferation, with opposing effects. We have profiled the components of the sphingolipid pathway on leukocytes of breast cancer (BC) patients undergoing chemotherapy treatment and without, including the five sphingosine 1-phosphate (S1P) receptors, the major functional genes, and cytokines, in order to better understand the S1P signaling in the immune cells of these patients. To the best of our knowledge, this is the first characterization of the sphingolipid pathway in whole blood of BC patients. Skewed gene profiles favoring high SPHK1 expression toward S1P production during BC development was observed, which was reversed by chemotherapy treatment, and reached similar levels to those found in healthy donors. Such levels were also correlated with high levels of TNF-α. Our data revealed an important role of the sphingolipid pathway in immune cells in BC with skewed signaling of S1P receptors, which favored cancer development even under chemotherapy, and may probably be a trigger of cancer resistance. Thus, these molecules must be considered as a target pathway for combined BC therapeutics.

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The barrier properties of endothelial cells are critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier function has been implicated in the genesis and/or progression of a variety of pathological conditions, including pulmonary edema, ischemic stroke, neurodegenerative disorders, angioedema, sepsis and cancer. The altered barrier function in these conditions is often linked to the release of soluble mediators from resident cells (e.g., mast cells, macrophages) and/or recruited blood cells. The interaction of the mediators with receptors expressed on the surface of endothelial cells diminishes barrier function either by altering the expression of adhesive proteins in the inter-endothelial junctions, by altering the organization of the cytoskeleton, or both. Reactive oxygen species (ROS), proteolytic enzymes (e.g., matrix metalloproteinase, elastase), oncostatin M, and VEGF are part of a long list of mediators that have been implicated in endothelial barrier failure. In this review, we address the role of blood borne cells, including, neutrophils, lymphocytes, monocytes, and platelets, in the regulation of endothelial barrier function in health and disease. Attention is also devoted to new targets for therapeutic intervention in disease states with morbidity and mortality related to endothelial barrier dysfunction.

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OBJECTIVE: To determine the prevalence of feeding dysfunction in children with single ventricle defects and identify associated risk factors. STUDY DESIGN: Patients aged 2-6 years with single ventricle physiology presenting for routine cardiology follow-up at the Children's Hospital of Wisconsin were prospectively identified. Parents of the patients completed 2 validated instruments for assessment of feeding dysfunction. Chart review was performed to retrospectively obtain demographic and diagnostic data. RESULTS: Instruments were completed for 56 patients; median age was 39 months. Overall, 28 (50%) patients had some form of feeding dysfunction. Compared with a normal reference population, patients with single ventricle had statistically significant differences in dysfunctional food manipulation (P < .001), mealtime aggression (P = .002), choking/gagging/vomiting (P < .001), resistance to eating (P < .001), and parental aversion to mealtime (P < .001). Weight and height for age z-scores were significantly lower in subjects with feeding dysfunction (-0.84 vs -0.33; P < .05 and -1.46 vs -0.56; P = .001, respectively). Multivariable analysis identified current gastrostomy tube use (P = .02) and a single parent household (P = .01) as risk factors for feeding dysfunction. CONCLUSION: Feeding dysfunction is common in children with single ventricle defects, occurring in 50% of our cohort. Feeding dysfunction is associated with worse growth measures. Current gastrostomy tube use and a single parent household were identified as independent risk factors for feeding dysfunction.

Assuntos

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The role of protein kinase C (PKC) isozymes in phorbol myristate acetate (PMA)-induced sphingosine 1-phosphate (S1P) receptor 1 (S1P1) phosphorylation was studied. Activation of S1P1 receptors induced an immediate increase in intracellular calcium, which was blocked by preincubation with PMA. Both S1P and PMA were able to increase S1P1 phosphorylation in a concentration- and time-dependent fashion. Down-regulation of PKC (overnight incubation with PMA) blocked the subsequent effect of the phorbol ester on S1P1 phosphorylation, without decreasing that of the natural agonist. Pharmacological inhibition of PKC α prevented the effects of PMA on S1P-triggered intracellular calcium increase and on S1P1 phosphorylation; no such effect was observed on the effects of the sphingolipid agonist. The presence of PKC α and ß isoforms in S1P1 immunoprecipitates was evidenced by Western blotting. Additionally, expression of dominant-negative mutants of PKC α or ß and knockdown of these isozymes using short hairpin RNA, markedly attenuated PMA-induced S1P1 phosphorylation. Our results indicate that the classical isoforms, mainly PKC α, mediate PMA-induced phosphorylation and desensitization of S1P1.

Assuntos