Assuntos
Eritromelalgia/fisiopatologia , Neuralgia/fisiopatologia , Potenciais de Ação , Adulto , Feminino , HumanosRESUMO
Interactions between blood vessels and osteoblasts-bone-forming cells-are critical for successful bone development. We therefore investigated the endothelial differentiation capacity of mesenchymal stem cells (MSCs) derived from bone tissue. We found that fetal pre-osteoblast and adult trabecular bone-derived (TB) MSCs express similar surface markers as bone marrow (BM) MSCs and can differentiate into adipocytes, osteoblasts, and chondrocytes. However, when cultured in extracellular matrix (ECM) and endothelial differentiation conditions, bone-derived MSCs (B-MSCs) more readily form tubular structures and uptake acetylated low-density lipoproteins, fulfilling the functional criteria for endothelial cells (ECs). Moreover, addition of B-MSCs but not other cells significantly enhanced vessel formation in the in vivo chick chorioallantoic membrane assay. Mechanistically, this appears to be due to the upregulation of the endothelial transcription factor forkhead box protein C2 (FOXC2) and its downstream gene αvß3 integrin/CD61in B-MSCs but not BMMSCs by laminin, a component protein of the ECM. Our findings not only reveal discrepant differentiation capacity for various tissue-specific MSCs, but also highlight the critical role of the niche-in this case, the ECM and its component proteins-in determining lineage commitment of stem cells.
Assuntos
Diferenciação Celular , Proteínas da Matriz Extracelular/metabolismo , Células Endoteliais da Veia Umbilical Humana/citologia , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Nicho de Células-Tronco , Adulto , Células-Tronco Adultas/citologia , Células-Tronco Adultas/metabolismo , Animais , Biomarcadores/metabolismo , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Diferenciação Celular/genética , Embrião de Galinha , Matriz Extracelular/metabolismo , Feto/citologia , Fatores de Transcrição Forkhead/metabolismo , Técnicas de Silenciamento de Genes , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Laminina/metabolismo , Neovascularização Fisiológica/genética , Osteoblastos/citologia , Osteoblastos/metabolismo , Nicho de Células-Tronco/genética , Fatores de Transcrição/metabolismo , Regulação para Cima/genéticaRESUMO
Current advances in stem cell biology have brought much hope for therapy of neuro-degenerative diseases. However, neural stem cells (NSCs) are rare adult stem cells, and the use of non-NSCs requires efficient and high-yielding lineage-specific differentiation prior to transplantation for efficacy. We report on the efficient differentiation of placental-derived multipotent cells (PDMCs) into a neural phenotype with use of Y-27632, a clinically compliant small molecular inhibitor of Rho kinase (ROCK) which is a major mediator of cytoskeleton dynamics. Y-27632 does not induce differentiation of PDMC toward the mesodermal lineages of adipogenesis and osteogenesis, but rather a neural-like morphology, with rapid development of cell extensions and processes within 24 h. Compared with conventional neurogenic differentiation agents, Y-27632 induces a higher percentage of neural-like cells in PDMCs without arresting proliferation or cell cycle dynamics. Y-27632-treated PDMCs express several neural lineage genes at the RNA and protein level, including nestin, MAP2, and GFAP. The effect of the ROCK inhibitor is cell-specific to PDMCs, and is mainly mediated through the ROCK2 isoform and its downstream target, myosin II. Our data suggest that ROCK inhibition and cytoskeletal rearrangement may allow for induction of a neural phenotype in PDMCs without compromising cell survival.
Assuntos
Amidas/farmacologia , Células-Tronco Multipotentes/citologia , Células-Tronco Multipotentes/enzimologia , Neurônios/citologia , Placenta/citologia , Piridinas/farmacologia , Quinases Associadas a rho/antagonistas & inibidores , Adipogenia/efeitos dos fármacos , Adipogenia/genética , Ciclo Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Forma Celular/genética , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Células-Tronco Multipotentes/efeitos dos fármacos , Miosina Tipo II/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Nestina , Neurônios/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Fenótipo , Gravidez , Quinases Associadas a rho/metabolismoRESUMO
Primary immune thrombocytopenia (ITP) of childhood is an autoimmune disease characterized by abnormally increased destruction of platelets and decreased megakaryopoiesis. Stromal-derived factor-1 (SDF-1) plays a role in megakaryopoiesis and may be involved in the pathogenesis of ITP. Five single nucleotide polymorphisms (SNPs) of the SDF-1 gene, including rs1801157, rs2839693, rs2297630, rs1065297, and rs266085, were assessed in 100 children with ITP and 126 healthy controls. The genotypes were analyzed by tetra ARMS polymerase chain reaction and confirmed by direct sequencing. Compared with controls, the rs2839693 A/A and rs266085 C/T genotypes were decreased in ITP patients (P = 0.004 and 0.007, respectively). The odds ratios of the latter genotypes were 0.48, 95% CI 0.28-0.82. Further analysis of the relationship between SDF-1 polymorphisms and clinical features showed that rs2297630 A/G was associated with protection from chronicity (P = 0.002; OR, 0.07; 95% CI, 0.01-0.61) and steroid dependence (P = 0.007; OR, 0.10; 95% CI, 0.01-0.84) in ITP patients. However, rs266085 genotype C/C was associated with risk of steroid dependence (P = 0.012, OR 3.87, 95% CI 1.27-11.77). The findings of this study suggest that SDF-1 gene variations may be associated with the occurrence and prognosis of childhood ITP.
Assuntos
Quimiocina CXCL12/genética , Polimorfismo de Nucleotídeo Único , Púrpura Trombocitopênica Idiopática/genética , Adolescente , Corticosteroides/uso terapêutico , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Humanos , Lactente , Masculino , Púrpura Trombocitopênica Idiopática/tratamento farmacológicoRESUMO
The biomass yield of a continuous flow activated sludge system varied when the system treated influent containing different compositions of biogenic and xenobiotic substrates. Both the biogenic substrate and a test xenobiotic 2,4-dichlorophenoxyacetic acid (2,4-D) were degraded at steady-state activated sludge operations. The true yields, determined from steady-state activated sludge treatment performances, were at the maximum and the minimum when the activated sludge treated the influent of sole biogenic substrate and sole 2,4-D, respectively. The minimum yield was 56% of the maximum. Yield reduction between the maximum and the minimum was proportional to the concentration of 2,4-D in the influent. This trend of yield reduction suited a model that describes the metabolic uncoupling effect of 2,4-D on the sludge's degradation of the substrates. The model function variable was defined as the ratio of 2,4-D to biogenic COD concentrations in the influent.
Assuntos
Ácido 2,4-Diclorofenoxiacético/metabolismo , Bactérias/metabolismo , Herbicidas/metabolismo , Modelos Biológicos , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Xenobióticos/metabolismo , Biodegradação Ambiental , BiomassaRESUMO
HSP90 chaperones are transducer proteins of many signaling pathways in cells. Using a highly specific inhibitor, geldanamycin (GA), an increasing number of the HSP90 client proteins have been identified. Nevertheless, there is little information on the differential transactivation of the two isoforms of the hsp90 genes, hsp90alpha and beta, in cells under stress conditions. Here, we demonstrate the differential expression of the HSP90 isoforms, HSP90alpha and beta, in rat gliosarcoma 9L cells using a modified SDS-PAGE system that allowed us to distinguish the isoforms. We subsequently assessed the transcriptional controls involving the transcription elements located in the promoter regions of the hsp90 genes. At the protein level, HSP90alpha is more responsive to GA in terms of rate of de novo synthesis and amount of accumulation, as shown by metabolic-labeling and Western-blotting analyses. Upregulation of the hsp90 genes was demonstrated by real-time qPCR. The promoter elements hsp90alpha-HSE2 and hsp90beta-HSE1 were also identified to be the major transcription elements involved in GA-activated gene expression, as shown by EMSA, whereas the results of supershift showed that the transcription factor HSF1 is also involved. Moreover, EMSA results of analysis of the GC box showed differences in both the initial amounts and inductive response of hsp90s transcripts, whereas analysis of the TATA box showed GA responsiveness in hsp90alpha only. Collectively, these results indicate that GA exerts its regulatory effects through transcription elements including heat-shock elements (HSEs), GC boxes and TATA boxes, resulting in differential transactivation of hsp90alpha and hsp90beta in rat gliosarcoma 9L cells.
Assuntos
Benzoquinonas/farmacologia , Elementos Facilitadores Genéticos/fisiologia , Gliossarcoma/patologia , Proteínas de Choque Térmico HSP90/genética , Lactamas Macrocíclicas/farmacologia , Ativação Transcricional , Animais , Linhagem Celular Tumoral , Proteínas de Choque Térmico HSP90/biossíntese , Proteínas de Choque Térmico HSP90/efeitos dos fármacos , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/efeitos dos fármacos , Isoformas de Proteínas/genética , Ratos , TATA BoxRESUMO
A series of heteroleptic Ir(III) metal complexes 1-3 bearing two N-phenyl-substituted pyrazoles and one 2-pyridyl pyrazole (or triazole) ligands were synthesized and characterized to attain highly efficient, room-temperature blue phosphorescence. The N-phenylpyrazole ligands, dfpzH = 1-(2,4-difluorophenyl)pyrazole, fpzH = 1-(4-fluorophenyl)pyrazole, dfmpzH = 1-(2,4-difluorophenyl)-3,5-dimethylpyrazole, and fmpzH = 1-(4-fluorophenyl)-3,5-dimethylpyrazole, show a similar reaction pattern with respect to the typical cyclometalated (C(wedge)N) chelate, which utilizes its ortho-substituted phenyl segment to link with the central Ir(III) atom, while the second 2-pyridylpyrazole (or triazole) ligand, namely, fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole, fptzH = 3-(trifluoromethyl)-5-(2-pyridyl)triazole, and hptzH = 3-(heptafluoropropyl)-5-(2-pyridyl)triazole, undergoes typical anionic (N--N) chelation to complete the octahedral framework. X-ray structural analyses on complexes [(dfpz)(2)Ir(fppz)] (1a) and [(fmpz)(2)Ir(hptz)] (3d) were established to confirm their molecular structures. Increases of the pipi energy gaps of the Ir(III) metal complexes were systematically achieved with two tuning strategies. One involves the substitution for one or two fluorine atoms at the N-phenyl segment or the introduction of two electron-releasing methyl substituents at the pyrazole segment of the H(C--N) ligands. Alternatively, we have applied the more electron-accepting triazolate in place of the pyrazolate segment for the third (N--N)H ligand. Our results, on the basis of steady-state, relaxation dynamics, and theoretical approaches, lead to a conclusion that, for complexes 1-3, the weakening of iridium metal-ligand bonding strength in the T(1) state plays a crucial role for the fast radiationless deactivation. For the case of [(fmpz)(2)Ir(hptz)] (3d), a thermal deactivation barrier of 4.8 kcal/mol was further deduced via temperature-dependent studies. The results provide a theoretical basis for future design and synthesis of the corresponding analogues suited to blue phosphorescent emitters.