RESUMO
Experimental studies have demonstrated that methylphenidate (MPH) modulates the synaptic vesicle trafficking and synaptotagmin-1 (SytI) mRNA levels. SytI is a regulatory protein of the SNARE complex, a neurotransmitter exocytosis mediator. Despite this evidence, most SNARE complex-related genes have never been evaluated in attention-deficit/hyperactivity disorder (ADHD) pharmacogenetics. This study evaluates, for we believe the first time, polymorphisms on the SNARE complex-related genes STX1A (rs2228607), VAMP2 (26bp Ins/Del) and SYT1 (rs1880867 and rs2251214) on the response to immediate-release methylphenidate (IR-MPH) in a naturalistic sample of adults with ADHD. The sample comprised 433 subjects, of which 272 (62.8%) have completed the short-term IR-MPH treatment (at least 30 days). The main outcome measure was the categorical variable of short-term response to IR-MPH based on the Swanson, Nolan and Pelham Rating Scale version 4 (SNAP-IV), and on the clinical global impression-improvement scale. Additional analyses evaluated the percentage of SNAP-IV symptom reduction for each dimension as well as short- and long- (7 years) term treatment persistence. SYT1-rs2251214 was associated with the categorical short-term response to IR-MPH (P=0.006, PFDR=0.028), and with the percentage of inattention and oppositional defiant disorder symptoms reduction (P=0.007, PFDR=0.028 and P=0.017, PFDR=0.048, respectively). SYT1-rs2251214 was also associated with short-term treatment persistence (P=0.018, PFDR=0.048), and with months of treatment (P=0.002, PFDR=0.016) in the long-term protocol. Our findings suggest that SYT1-rs2251214 presents a broad influence in IR-MPH response variability in adults with ADHD, being involved with both symptom response and treatment persistence. If such findings are replicated, SytI could represent a key element in MPH pharmacodynamics in adults with ADHD.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/genética , Exocitose/genética , Sinaptotagmina I/genética , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/complicações , Estimulantes do Sistema Nervoso Central , Exocitose/fisiologia , Feminino , Humanos , Masculino , Metilfenidato/farmacologia , Metilfenidato/uso terapêutico , Avaliação de Resultados em Cuidados de Saúde , Polimorfismo Genético , Sinaptotagmina I/metabolismo , Sintaxina 1/genética , Sintaxina 1/metabolismo , Resultado do Tratamento , Proteína 2 Associada à Membrana da Vesícula/genética , Proteína 2 Associada à Membrana da Vesícula/metabolismoRESUMO
AIM: The maternal environment during pregnancy and lactation plays a determining role in programming energy metabolism in offspring. Among a myriad of maternal factors, disruptions in the light/dark cycle during pregnancy can program glucose intolerance in offspring. Out-of-phase feeding has recently been reported to influence metabolism in adult humans and rodents; however, it is not known whether this environmental factor impacts offspring metabolism when applied during pregnancy and lactation. This study aims to determine whether maternal day-restricted feeding (DF) influences energy metabolism in offspring. METHODS: Pregnant and lactating Wistar rats were subjected to ad libitum (AL) or DF during pregnancy and lactation. The offspring born to the AL and DF dams were intra- and interfostered, which resulted in 4 group types. RESULTS: The male offspring born to and breastfed by the DF dams (DF/DF off) were glucose intolerant, but without parallel insulin resistance as adults. Experiments with isolated pancreatic islets demonstrated that the male DF/DF off rats had reduced insulin secretion with no parallel disruption in calcium handling. However, this reduction in insulin secretion was accompanied by increased miRNA-29a and miRNA34a expression and decreased syntaxin 1a protein levels. CONCLUSION: We conclude that out-of-phase feeding during pregnancy and lactation can lead to glucose intolerance in male offspring, which is caused by a disruption in insulin secretion capacity. This metabolic programming is possibly caused by mechanisms dependent on miRNA modulation of syntaxin 1a.
Assuntos
Restrição Calórica/efeitos adversos , Insulina/metabolismo , Lactação/fisiologia , Prenhez/metabolismo , Animais , Cálcio/metabolismo , Metabolismo Energético/fisiologia , Feminino , Intolerância à Glucose/metabolismo , Técnicas In Vitro , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Masculino , MicroRNAs/biossíntese , MicroRNAs/genética , NADP/metabolismo , Gravidez , Ratos , Ratos Wistar , Sintaxina 1/biossíntese , Sintaxina 1/genéticaRESUMO
During pregnancy and the perinatal period of life, prolactin (PRL) and other lactogenic substances induce adaptation and maturation of the stimulus-secretion coupling system in pancreatic beta-cells. Since the SNARE molecules, SNAP-25, syntaxin 1, VAMP-2, and synaptotagmins participate in insulin secretion, we investigated whether the improved secretory response to glucose during these periods involves alteration in the expression of these proteins. mRNA was extracted from neonatal rat islets cultured for 5 days in the presence of PRL and from pregnant rats (17th-18th days of pregnancy) and reverse transcribed. The expression of genes was analyzed by semi-quantitative RT-PCR assay. The expression of proteins was analyzed by Western blotting and confocal microscopy. Transcription and expression of all SNARE genes and proteins were increased in islets from pregnant and PRL-treated neonatal rats when compared with controls. The only exception was VAMP-2 production in islets from pregnant rats. Increased mRNA and protein expression of synaptotagmin IV, but not the isoform I, also was observed in islets from pregnant and PRL-treated rats. This effect was not inhibited by wortmannin or PD098059, inhibitors of the PI3-kinase and MAPK pathways, respectively. As revealed by confocal laser microscopy, both syntaxin 1A and synaptotagmin IV were immunolocated in islet cells, including the insulin-containing cells. These results indicate that PRL modulates the final steps of insulin secretion by increasing the expression of proteins involved in membrane fusion.
Assuntos
Regulação da Expressão Gênica no Desenvolvimento/genética , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Prolactina/farmacologia , Proteínas SNARE/genética , Sinaptotagminas/genética , Animais , Animais Recém-Nascidos , Western Blotting , Eletroforese em Gel de Poliacrilamida , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Immunoblotting , Imunoquímica , Insulina/genética , Secreção de Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/embriologia , Microscopia Confocal , Gravidez , RNA Mensageiro/análise , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas SNARE/metabolismo , Proteína 25 Associada a Sinaptossoma/genética , Proteína 25 Associada a Sinaptossoma/metabolismo , Sinaptotagminas/metabolismo , Sintaxina 1/genética , Sintaxina 1/metabolismo , Proteína 2 Associada à Membrana da Vesícula/genética , Proteína 2 Associada à Membrana da Vesícula/metabolismoRESUMO
During pregnancy and the perinatal period of life, prolactin (PRL) and other lactogenic substances induce adaptation and maturation of the stimulus-secretion coupling system in pancreatic â-cells. Since the SNARE molecules, SNAP-25, syntaxin 1, VAMP-2, and synaptotagmins participate in insulin secretion, we investigated whether the improved secretory response to glucose during these periods involves alteration in the expression of these proteins. mRNA was extracted from neonatal rat islets cultured for 5 days in the presence of PRL and from pregnant rats (17th-18th days of pregnancy) and reverse transcribed. The expression of genes was analyzed by semi-quantitative RT-PCR assay. The expression of proteins was analyzed by Western blotting and confocal microscopy. Transcription and expression of all SNARE genes and proteins were increased in islets from pregnant and PRL-treated neonatal rats when compared with controls. The only exception was VAMP-2 production in islets from pregnant rats. Increased mRNA and protein expression of synaptotagmin IV, but not the isoform I, also was observed in islets from pregnant and PRL-treated rats. This effect was not inhibited by wortmannin or PD098059, inhibitors of the PI3-kinase and MAPK pathways, respectively. As revealed by confocal laser microscopy, both syntaxin 1A and synaptotagmin IV were immunolocated in islet cells, including the insulin-containing cells. These results indicate that PRL modulates the final steps of insulin secretion by increasing the expression of proteins involved in membrane fusion.