RESUMO
Glioma is the most common form of malignant brain cancer in adults. The Sleeping Beauty (SB) transposon-based glioma mouse model allows for effective in vivo analysis of candidate genes. In the present study, we developed a transposon vector that encodes the triple combination of platelet-derived growth factor subunit A (PDGFA), and shRNAs against Nf1 and Trp53 (shNf1/shp53). Initiation and progression of glioma in the brain were monitored by expression of a fluorescent protein. Transduction of the vector into neural progenitor and stem cells (NPC) in the subventricular zone (SVZ) of the neonatal brain induced proliferation of oligodendrocyte precursor cells, and promoted formation of highly penetrant malignant gliomas within 2-4 months. Cells isolated from the tumors were capable of forming secondary tumors. Two transposon vectors, encoding either PDGFA or shNf1/shp53 were co-electroporated into NPC. Cells expressing PDGFA or shNf1/shp53 were labeled with unique fluorescent proteins allowing visualization of the spatial distribution of cells with different genetic alterations within the same tumor. Tumor cells located at the center of tumors expressed PDGFA at higher levels than those located at the periphery, indicating that intratumoral heterogeneity in PDGFA expression levels spontaneously developed within the same tumor. Tumor cells comprising the palisading necrosis strongly expressed PDGFA, suggesting that PDGFA signaling is involved in hypoxic responses in glioma. The transposon vectors developed are compatible with any genetically engineered mouse model, providing a useful tool for the functional analysis of candidate genes in glioma.
Assuntos
Neoplasias Encefálicas/etiologia , Elementos de DNA Transponíveis/genética , Modelos Animais de Doenças , Glioma/etiologia , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Hipóxia Celular , Proliferação de Células , Glioma/genética , Glioma/patologia , Camundongos , Camundongos Endogâmicos ICR , Células NIH 3T3 , Neurofibromina 1/genética , Fator de Crescimento Derivado de Plaquetas/genética , Fator de Crescimento Derivado de Plaquetas/fisiologia , Transdução de Sinais , Proteína Supressora de Tumor p53/genéticaRESUMO
It is desirable to produce beef with high levels of monounsaturated fatty acids (MUFA), as this is related to fat softness and palatability. However, the physiology of MUFA synthesis in bovine fat during the fattening process remains to be established. In this study, in order to elucidate the relationship between plasma components and the fatty acid composition of intramuscular fat, we investigated the effect of plasma obtained from fattening cattle on the messenger RNA (mRNA) expressions of the adipogenesis-related gene in a clonal bovine intramuscular preadipocyte line (BIP cells). The mRNA expressions of stearoyl-CoA desaturase, adipocyte Protein 2, peroxisome proliferator-activated receptor gamma and sterol regulatory element-binding protein 1 in BIP cells were significantly higher following treatment with those plasma samples collected from the cattle with the highest diaphragmatic unsaturated fatty acids to saturated fatty acids ratio (US/S). Furthermore, the concentration of nonesterified fatty acid (NEFA) in the plasma samples had an inverse correlation with carcass diaphragmatic US/S. These results indicate that cattle with a low ratio of US/S in fat may be discriminated from the population of fattening cattle before slaughter by measuring the effect of their plasma on gene expression in BIP cells as well as their plasma concentration and composition of NEFA.
Assuntos
Adipócitos/metabolismo , Adipogenia/genética , Tecido Adiposo/metabolismo , Bovinos/genética , Bovinos/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Qualidade dos Alimentos , Expressão Gênica , Carne Vermelha , Animais , Diafragma/metabolismo , Ácidos Graxos/metabolismo , Ácidos Graxos não Esterificados/sangue , Ácidos Graxos Insaturados/metabolismo , Feminino , Masculino , PPAR gama/genética , PPAR gama/metabolismo , RNA Mensageiro/metabolismo , Estearoil-CoA Dessaturase/genética , Estearoil-CoA Dessaturase/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genéticaRESUMO
In mice, peripheral 5-HT induces an increase in the plasma concentrations of glucose, insulin and bile acids, and a decrease in plasma triglyceride, NEFA and cholesterol concentrations. However, given the unique characteristics of the metabolism of ruminants relative to monogastric animals, the physiological role of peripheral 5-HT on glucose and lipid metabolism in sheep remains to be established. Therefore, in this study, we investigated the effect of 5-HT on the circulating concentrations of metabolites and insulin using five 5-HT receptor (5HTR) antagonists in sheep. After fasting for 24 h, sheep were intravenously injected with 5-HT, following which-, plasma glucose, insulin, triglyceride and NEFA concentrations were significantly elevated. In contrast, 5-HT did not affect the plasma cholesterol concentration, and it induced a decrease in bile acid concentrations. Increases in plasma glucose and insulin concentrations induced by 5-HT were attenuated by pre-treatment with Methysergide, a 5HTR 1, 2 and 7 antagonist. Additionally, decreased plasma bile acid concentrations induced by 5-HT were blocked by pre-treatment with Ketanserin, a 5HTR 2A antagonist. However, none of the 5HTR antagonists inhibited the increase in plasma triglyceride and NEFA levels induced by 5-HT. On the other hand, mRNA expressions of 5HTR1D and 1E were observed in the liver, pancreas and skeletal muscle. These results suggest that there are a number of differences in the physiological functions of peripheral 5-HT with respect to lipid metabolism between mice and sheep, though its effect on glucose metabolism appears to be similar between these species.
