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1.
BMC Geriatr ; 23(1): 74, 2023 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-36739383

RESUMO

BACKGROUND: Mild cognitive impairment (MCI) is not just a prodrome to dementia, but a very important intervention point to prevent dementia caused by Alzheimer's disease (AD). It has long been known that people with AD have a higher frequency of falls with some gait instability. Recent evidence suggests that vestibular impairment is disproportionately prevalent among individuals with MCI and dementia due to AD. Therefore, we hypothesized that the measurement of balance capability is helpful to identify individuals with MCI. METHODS: First, we developed a useful method to evaluate balance capability as well as vestibular function using Nintendo Wii balance board as a stabilometer and foam rubber on it. Then, 49 healthy volunteers aged from 56 to 75 with no clinically apparent cognitive impairment were recruited and the association between their balance capability and cognitive function was examined. Cognitive functions were assessed by MoCA, MMSE, CDR, and TMT-A and -B tests. RESULTS: The new balance capability indicator, termed visual dependency index of postural stability (VPS), was highly associated with cognitive impairment assessed by MoCA, and the area under the receiver operating characteristic (ROC) curve was more than 0.8, demonstrating high sensitivity and specificity (app. 80% and 60%, respectively). CONCLUSIONS: Early evidence suggests that VPS measured using Nintendo Wii balance board as a stabilometer helps identify individuals with MCI at an early and preclinical stage with high sensitivity, establishing a useful method to screen MCI.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Idoso , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/epidemiologia , Disfunção Cognitiva/complicações , Doença de Alzheimer/diagnóstico , Cognição , Curva ROC , Testes Neuropsicológicos , Sensibilidade e Especificidade
2.
Biochem Biophys Res Commun ; 582: 35-42, 2021 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-34688045

RESUMO

High protein diet (HPD) is an affordable and positive approach in prevention and treatment of many diseases. It is believed that transcriptional regulation is responsible for adaptation after HPD feeding and Kruppel-like factor 15 (KLF15), a zinc finger transcription factor that has been proved to perform transcriptional regulation over amino acid, lipid and glucose metabolism, is known to be involved at least in part in this HPD response. To gain more insight into molecular mechanisms by which HPD controls expressions of genes involved in amino acid metabolism in the liver, we performed RNA-seq analysis of mice fed HPD for a short period (3 days). Compared to a low protein diet, HPD feeding significantly increased hepatic expressions of enzymes involved in the breakdown of all the 20 amino acids. Moreover, using KLF15 knockout mice and in vivo Ad-luc analytical system, we were able to identify Cth (cystathionine gamma-lyase) as a new target gene of KLF15 transcription as well as Ast (aspartate aminotransferase) as an example of KLF15-independent gene despite its remarkable responsiveness to HPD. These findings provide us with a clue to elucidate the entire transcriptional regulatory mechanisms of amino acid metabolic pathways.


Assuntos
Aspartato Aminotransferases/genética , Cistationina gama-Liase/genética , Dieta Rica em Proteínas/métodos , Fatores de Transcrição Kruppel-Like/genética , Transcrição Gênica , Adaptação Fisiológica/genética , Aminoácidos/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Cistationina gama-Liase/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Genes Reporter , Glucose/metabolismo , Fatores de Transcrição Kruppel-Like/deficiência , Metabolismo dos Lipídeos/genética , Fígado/metabolismo , Luciferases , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Sequência de RNA , Transdução de Sinais
3.
Hepatology ; 71(5): 1609-1625, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31529722

RESUMO

BACKGROUND AND AIMS: Dysfunctional hepatic lipid metabolism is a cause of nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disorder worldwide, and is closely associated with insulin resistance and type 2 diabetes. ELOVL fatty acid elongase 6 (Elovl6) is responsible for converting C16 saturated and monounsaturated fatty acids (FAs) into C18 species. We have previously shown that Elovl6 contributes to obesity-induced insulin resistance by modifying hepatic C16/C18-related FA composition. APPROACH AND RESULTS: To define the precise molecular mechanism by which hepatic Elovl6 affects energy homeostasis and metabolic disease, we generated liver-specific Elovl6 knockout (LKO) mice. Unexpectedly, LKO mice were not protected from high-fat diet-induced insulin resistance. Instead, LKO mice exhibited higher insulin sensitivity than controls when consuming a high-sucrose diet (HSD), which induces lipogenesis. Hepatic patatin-like phospholipase domain-containing protein 3 (Pnpla3) expression was down-regulated in LKO mice, and adenoviral Pnpla3 restoration reversed the enhancement in insulin sensitivity in HSD-fed LKO mice. Lipidomic analyses showed that the hepatic ceramide(d18:1/18:0) content was lower in LKO mice, which may explain the effect on insulin sensitivity. Ceramide(d18:1/18:0) enhances protein phosphatase 2A (PP2A) activity by interfering with the binding of PP2A to inhibitor 2 of PP2A, leading to Akt dephosphorylation. Its production involves the formation of an Elovl6-ceramide synthase 4 (CerS4) complex in the endoplasmic reticulum and a Pnpla3-CerS4 complex on lipid droplets. Consistent with this, liver-specific Elovl6 deletion in ob/ob mice reduced both hepatic ceramide(d18:1/18:0) and PP2A activity and ameliorated insulin resistance. CONCLUSIONS: Our study demonstrates the key role of hepatic Elovl6 in the regulation of the acyl-chain composition of ceramide and that C18:0-ceramide is a potent regulator of hepatic insulin signaling linked to Pnpla3-mediated NAFLD.


Assuntos
Ceramidas/metabolismo , Elongases de Ácidos Graxos/fisiologia , Resistência à Insulina/genética , Fígado/enzimologia , Animais , Ceramidas/química , Sacarose Alimentar/administração & dosagem , Regulação para Baixo , Elongases de Ácidos Graxos/genética , Camundongos , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Fosfolipases A2 Independentes de Cálcio/metabolismo , Proteína Fosfatase 2/metabolismo , Esfingosina N-Aciltransferase/metabolismo
4.
J Exerc Sci Fit ; 19(3): 178-181, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33936218

RESUMO

BACKGROUND: Catecholamine is a typical index of exercise intensity, but it is difficult to detect. Plasma metanephrine (MN) and normethanephrine (NMN) levels are more stable than those of catecholamines. This study aimed to investigate plasma MN and NMN levels during acute exercise running in amateur runners. METHODS: Samples were collected from eight healthy male participants. They were either sedentary or running at low or high intensity for 30 min. Blood samples were collected under these conditions. Measurements taken included plasma adrenaline, noradrenaline, MN, and NMN. RESULTS: Plasma adrenaline levels increased after high-intensity exercise compared with sedentary subjects. Plasma noradrenaline, MN, and NMN levels increased after both low- and high-intensity exercise compared with sedentary subjects. In addition, these levels were also significantly higher at high intensity than at low intensity. Plasma adrenaline and noradrenaline levels were positively correlated with plasma free MN and NMN levels after acute running, respectively. CONCLUSION: This study revealed that plasma MN and NMN levels transiently increased depending on exercise intensity in amateur runners. In addition, plasma NMN levels are better markers than plasma MN levels because of their stronger correlation with plasma catecholamine levels.

5.
Int J Mol Sci ; 21(13)2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32605164

RESUMO

Local cryotherapy is widely used as a treatment for sports-related skeletal muscle injuries. The molecular mechanisms are unknown. To clarify these mechanisms, we applied one to three 15-min cold stimulations at 4 °C to various cell lines (in vitro), the tibialis anterior (TA) muscle (ex vivo), and mouse limbs (in vivo). In the in vitro assay, cyclic AMP (cAMP) response element binding protein 1 (CREB1) was markedly phosphorylated (p-CREB1), and the CREB-binding protein (CBP) was recruited to p-CREB-1 in response to two or three cold stimulations. In a reporter assay with the cAMP-responsive element, the signals significantly increased after two to three cold stimulations at 4 °C. In the ex vivo study, CREB-targeting genes were significantly upregulated following two or three cold stimulations. The in vivo experiment disclosed that cold stimulation of a mouse limb for 9 days significantly increased mitochondrial DNA copy number and upregulated genes involved in mitochondrial biogenesis. The results suggest that local cryotherapy increases CREB transcription and upregulates CREB-targeting genes, in a manner dependent on cold stimulation frequency and duration. This information will inform further investigations into local cryotherapy as a treatment for sports-related skeletal muscle trauma.


Assuntos
Crioterapia/métodos , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Músculo Esquelético/fisiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Animais , Proteínas Quinases Dependentes de AMP Cíclico/genética , Masculino , Camundongos , Camundongos Endogâmicos CBA , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Fosforilação , Transdução de Sinais , Ativação Transcricional
6.
Biochem Biophys Res Commun ; 493(1): 40-45, 2017 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-28928093

RESUMO

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have both anti-diabetic and anti-obesity effects. However, the precise mechanism of the anti-obesity effect remains unclear. We previously demonstrated that the glycogen depletion signal triggers lipolysis in adipose tissue via liver-brain-adipose neurocircuitry. In this study, therefore, we investigated whether the anti-obesity mechanism of SGLT2 inhibitor is mediated by this mechanism. Diet-induced obese mice were subjected to hepatic vagotomy (HVx) or sham operation and loaded with high fat diet containing 0.015% tofogliflozin (TOFO), a highly selective SGLT2 inhibitor, for 3 weeks. TOFO-treated mice showed a decrease in fat mass and the effect of TOFO was attenuated in HVx group. Although both HVx and sham mice showed a similar level of reduction in hepatic glycogen by TOFO treatment, HVx mice exhibited an attenuated response in protein phosphorylation by protein kinase A (PKA) in white adipose tissue compared with the sham group. As PKA pathway is known to act as an effector of the liver-brain-adipose axis and activate triglyceride lipases in adipocytes, these results indicated that SGLT2 inhibition triggered glycogen depletion signal and actuated liver-brain-adipose axis, resulting in PKA activation in adipocytes. Taken together, it was concluded that the effect of SGLT2 inhibition on weight loss is in part mediated via the liver-brain-adipose neurocircuitry.


Assuntos
Tecido Adiposo/fisiologia , Compostos Benzidrílicos/administração & dosagem , Encéfalo/fisiologia , Glucosídeos/administração & dosagem , Fígado/fisiologia , Inibidores do Transportador 2 de Sódio-Glicose , Transportador 2 de Glucose-Sódio/metabolismo , Redução de Peso/fisiologia , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/inervação , Animais , Fármacos Antiobesidade/administração & dosagem , Encéfalo/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/inervação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vagotomia , Nervo Vago/efeitos dos fármacos , Nervo Vago/fisiologia , Nervo Vago/cirurgia
7.
Neurochem Res ; 41(4): 696-706, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26620190

RESUMO

Germline mutations in genes encoding succinate dehydrogenase subunits are associated with the development of familial pheochromocytomas and paragangliomas [hereditary paraganglioma/pheochromocytoma syndrome (HPPS)]. In particular, a mutation in succinate dehydrogenase subunit B (SDHB) is highly associated with abdominal paraganglioma and subsequent distant metastasis (malignant paraganglioma), indicating the importance of SDHB genetic testing. The discovery of HPPS suggests an association among genetic mitochondrial defects, tumor development, and catecholamine oversecretion. To investigate this association, we transfected pheochromocytoma cells (PC12) with SDHB-specific siRNA. SDHB silencing virtually abolished complex II activity, demonstrating the utility of this in vitro model for investigating the pseudo-hypoxic drive hypothesis. Lack of complex II activity resulting from RNA interference of SDHB increased tyrosine hydroxylase (TH; the rate-limiting enzyme in catecholamine biosynthesis) activity and catecholamine secretion. Reduced apoptosis was observed accompanied by Bcl-2 accumulation in PC12 cells, consistent with the phenotypes of paragangliomas with SDHB mutations. In addition, SDHB silencing increased reactive oxygen species (ROS) production and nuclear HIF1α stabilization under normoxic conditions. Furthermore, phenotypes induced by complex II activity knockdown were abolished by pretreatment with N-acetyl cysteine (an ROS scavenger) and by prior HIF1α knockdown, indicating an ROS- and HIF1α-dependent mechanism. Our results indicate that increased ROS may act as signal transduction messengers that induce HIF1α stabilization and may be necessary for the pseudo-hypoxic states observed in our experimental model. To our knowledge, this is the first study demonstrating that pseudo-hypoxic states resulting from SDHB knockdown are associated with increased TH activity and catecholamine oversecretion.


Assuntos
Catecolaminas/biossíntese , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Succinato Desidrogenase/metabolismo , Animais , Apoptose , Catecolaminas/metabolismo , Sobrevivência Celular , Complexo II de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Mutação , Células PC12 , Paraganglioma/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Interferente Pequeno/genética , Ratos , Succinato Desidrogenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo
8.
Biochem Biophys Res Commun ; 465(4): 857-63, 2015 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-26321664

RESUMO

Fatty acid elongase 5 (ELOVL5) is an enzyme involved in the synthesis of polyunsaturated fatty acids. Sterol Regulatory Element-binding Protein (SREBP)-1 activates ELOVL5 and increases polyunsaturated fatty acid synthesis, which in turn negatively affects SREBP-1 expression. Thus, ELOVL5 has been established as an SREBP-1 target gene and an important component of the negative feedback loop of de novo lipogenesis. However, the human ELOVL5 promoter/enhancer has not been fully analyzed and the location of SREBP biding sites around the ELOVL5 gene has yet to be defined. Here we performed a detailed promoter/enhancer analysis of human ELOVL5 gene, and identified two new SREBP binding sites, one in the 10 kb upstream region and one in the exon 1. These two SRE motifs are conserved among mammals and the mechanism found in the present study by which SREBP activates ELOVL5 is considered to be common in mammals. Through these findings, we clarified the molecular mechanism how SREBP activates ELOVL5, an important regulator of de novo lipogenesis.


Assuntos
Acetiltransferases/genética , Elementos Facilitadores Genéticos , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Animais , Sequência de Bases , Sítios de Ligação/genética , Éxons , Elongases de Ácidos Graxos , Ácidos Graxos Insaturados/metabolismo , Ácidos Graxos Insaturados/farmacologia , Células HEK293 , Humanos , Lipogênese/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Regiões Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Regulação para Cima
9.
FEBS J ; 291(2): 259-271, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37702262

RESUMO

During periods of fasting, the body undergoes a metabolic shift from carbohydrate utilization to the use of fats and ketones as an energy source, as well as the inhibition of de novo lipogenesis and the initiation of gluconeogenesis in the liver. The transcription factor sterol regulatory element-binding protein-1 (SREBP-1), which plays a critical role in the regulation of lipogenesis, is suppressed during fasting, resulting in the suppression of hepatic lipogenesis. We previously demonstrated that the interaction of fasting-induced Kruppel-like factor 15 (KLF15) with liver X receptor serves as the essential mechanism for the nutritional regulation of SREBP-1 expression. However, the underlying mechanisms of KLF15 induction during fasting remain unclear. In this study, we show that the glucocorticoid receptor (GR) regulates the hepatic expression of KLF15 and, subsequently, lipogenesis through the KLF15-SREBP-1 pathway during fasting. KLF15 is necessary for the suppression of SREBP-1 by GR, as demonstrated through experiments using KLF15 knockout mice. Additionally, we show that GR is involved in the fasting response, with heightened binding to the KLF15 enhancer. It has been widely known that the hypothalamic-pituitary-adrenal (HPA) axis regulates the secretion of glucocorticoids and plays a significant role in the metabolic response to undernutrition. These findings demonstrate the importance of the HPA-axis-regulated GR-KLF15 pathway in the regulation of lipid metabolism in the liver during fasting.


Assuntos
Lipogênese , Receptores de Glucocorticoides , Camundongos , Animais , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Lipogênese/genética , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Regiões Promotoras Genéticas , Fígado/metabolismo , Jejum
10.
BBA Adv ; 3: 100078, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37082255

RESUMO

ELOVL fatty acid elongase 6 (ELOVL6) controls cellular fatty acid (FA) composition by catalyzing the elongation of palmitate (C16:0) to stearate (C18:0) and palmitoleate (C16:1n-7) to vaccinate (C18:1n-7). Although the transcriptional regulation of ELOVL6 has been well studied, the post-transcriptional regulation of ELOVL6 is not fully understood. Therefore, this study aims to evaluate the role of microRNAs (miRNAs) in regulating human ELOVL6. Bioinformatic analysis identified five putative miRNAs: miR-135b-5p, miR-135a-5p, miR-125a-5p, miR-125b-5p, and miR-22-3p, which potentially bind ELOVL6 3'-untranslated region (UTR). Results from dual-luciferase assays revealed that these miRNAs downregulate ELOVL6 by directly interacting with the 3'-UTR of ELOVL6 mRNA. Moreover, miR-135b-5p and miR-135a-5p suppress cell proliferation and migration in glioblastoma multiforme cells by inhibiting ELOVL6 at the mRNA and protein levels. Taken together, our results provide novel regulatory mechanisms for ELOVL6 at the post-transcriptional level and identify potential candidates for the treatment of patients with glioblastoma multiforme.

11.
PNAS Nexus ; 2(11): pgad351, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37954160

RESUMO

The endoplasmic reticulum (ER)-embedded transcription factors, sterol regulatory element-binding proteins (SREBPs), master regulators of lipid biosynthesis, are transported to the Golgi for proteolytic activation to tune cellular cholesterol levels and regulate lipogenesis. However, mechanisms by which the cell responds to the levels of saturated or unsaturated fatty acids remain underexplored. Here, we show that RHBDL4/RHBDD1, a rhomboid family protease, directly cleaves SREBP-1c at the ER. The p97/VCP, AAA-ATPase complex then acts as an auxiliary segregase to extract the remaining ER-embedded fragment of SREBP-1c. Importantly, the enzymatic activity of RHBDL4 is enhanced by saturated fatty acids (SFAs) but inhibited by polyunsaturated fatty acids (PUFAs). Genetic deletion of RHBDL4 in mice fed on a Western diet enriched in SFAs and cholesterol prevented SREBP-1c from inducing genes for lipogenesis, particularly for synthesis and incorporation of PUFAs, and secretion of lipoproteins. The RHBDL4-SREBP-1c pathway reveals a regulatory system for monitoring fatty acid composition and maintaining cellular lipid homeostasis.

12.
Am J Physiol Endocrinol Metab ; 302(6): E615-25, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21878661

RESUMO

Sunitinib is an oral multitargeted receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity that mainly targets vascular endothelial growth factor receptors (VEGFRs). Very recently, sunitinib has been shown to be an active agent for the treatment of malignant pheochromocytomas. However, it is unclear whether sunitinib acts only through an antiangiogenic mechanism or whether it may also directly target tumor cells. Sunitinib markedly induced apoptosis of PC12 cells in a dose-dependent and time-dependent manner. Furthermore, in support of these findings, we found that sunitinib induced a reduction in the expression of the antiapoptotic molecule Bcl-2 as well as dephosphorylation of the proapoptotic molecule BAD, which results in the activation of BAD in these cells. Consistent with these apoptotic effects, our results showed that sunitinib inhibited phosphorylation of Akt and mTOR and was followed by a reduction of S6K1, which is a well-known target of mTOR. Knockdown of VEGFR-2 attenuated the sunitinib-induced effects, including apoptosis and inhibition of signaling pathways such as the phosphorylation of Akt as well as mTOR, and Bcl-2, which confirmed that these effects could be mediated by VEGFR-2. In addition, silencing of S6K1 induced apoptosis accompanied by a decrease in the phosphorylation of BAD and Bcl-2, similar to that observed with sunitinib treatment. Thus, these results together suggest that sunitinib initially exerts its apoptotic effect through the inhibition of VEGFR-2, which, when followed by reduction of its downstream effectors, including Akt/mTOR/S6K1, may lead to inhibition of the antiapoptotic molecule Bcl-2 and activation of the proapoptotic molecule BAD in PC12 cells. However, PC12 cells do not precisely reflect the pathogenesis of malignant cells. Therefore, we confirmed the key findings by replicating these experiments in human neuroblastoma SK-N-SH cells.


Assuntos
Inibidores da Angiogênese/farmacologia , Apoptose/efeitos dos fármacos , Indóis/farmacologia , Proteína Oncogênica v-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirróis/farmacologia , Proteínas Quinases S6 Ribossômicas/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Proteína de Morte Celular Associada a bcl/metabolismo , Animais , Antimetabólitos Antineoplásicos , Western Blotting , Bromodesoxiuridina , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Corantes , Marcação In Situ das Extremidades Cortadas , Indicadores e Reagentes , Análise em Microsséries , Células PC12 , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , RNA Interferente Pequeno/genética , Ratos , Sunitinibe , Sais de Tetrazólio , Tiazóis , Proteína de Morte Celular Associada a bcl/efeitos dos fármacos
13.
Am J Physiol Endocrinol Metab ; 303(8): E1006-14, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-22912364

RESUMO

Sunitinib is an oral, small molecule multitargeted receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity that primarily targets vascular endothelial growth factor receptors (VEGFRs). Although sunitinib is an active agent for the treatment of malignant pheochromocytomas, it is unclear whether sunitinib acts through only antiangiogenic mechanisms or also directly targets tumor cells. We previously showed that sunitinib directly induced apoptosis of PC-12 cells. To further confirm these direct effects, we examined the effects of sunitinib on tyrosine hydroxylase (TH) (the rate-limiting enzyme in catecholamine biosynthesis) activity and catecholamine secretion in PC-12 cells and the underlying mechanisms. Sunitinib inhibited TH activity in a dose-dependent manner, and decreased TH protein levels. Consistent with this finding, sunitinib decreased TH phosphorylation at Ser(31) and Ser(40) and significantly decreased catecholamine secretion. VEGFR-2 knockdown attenuated these effects, including inhibition of TH activity and catecholamine secretion, suggesting that they were mediated by VEGFR-2. Sunitinib significantly decreased phospholipase C (PLC)-γ phosphorylation and subsequent protein kinase C (PKC) activity. Because Ser(40) phosphorylation significantly affects TH activity and is known to be regulated by PKC, sunitinib may inhibit Ser(40) phosphorylation via the VEGFR-2/PLC-γ/PKC pathway. Additionally, sunitinib markedly decreased the activity of extracellular signal-regulated kinase (ERK), but not c-Jun NH(2)-terminal kinase or p38 mitogen-activated protein kinase. Therefore, sunitinib may reduce TH Ser(31) phosphorylation through inhibition of the VEGFR-2/PLC-γ/PKC/Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/ERK pathway. Sunitinib also significantly reduced inositol 1,4,5-trisphosphate production. However, because PC-12 cells do not precisely reflect the pathogenesis of malignant cells, we confirmed the key findings in a human neuroblastoma cell line, SK-N-SH. In conclusion, sunitinib directly inhibits catecholamine synthesis and secretion in pheochromocytoma PC-12 cells.


Assuntos
Inibidores da Angiogênese/farmacologia , Catecolaminas/biossíntese , Catecolaminas/metabolismo , Indóis/farmacologia , Fosfolipase C gama/metabolismo , Pirróis/farmacologia , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Western Blotting , Linhagem Celular Tumoral , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Inositol 1,4,5-Trifosfato/biossíntese , Células PC12 , Feocromocitoma/metabolismo , Proteína Quinase C/metabolismo , RNA Interferente Pequeno/genética , Ratos , Transdução de Sinais/efeitos dos fármacos , Sunitinibe , Tirosina 3-Mono-Oxigenase/metabolismo
14.
Clin Endocrinol (Oxf) ; 77(5): 707-14, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22541004

RESUMO

OBJECTIVE: Recently, TMEM127 was shown to be a new pheochromocytoma susceptibility gene; this is consistent with its function as a tumour suppressor gene (Journal of Clinical Endocrinology and Metabolism, 2009, 94, 2817). Most pheochromocytomas arise from the adrenal medulla, and in approximately half of the cases, the tumours are bilateral (Journal of Clinical Endocrinology and Metabolism, 2009, 94, 2817; Journal of the American Medical Association, 2004, 292, 943; Human Mutation, 2010, 31, 41; Science, 2009, 325, 1139). The aim of the present study was to determine whether TMEM127 mutations are involved in the pathogenesis of pheochromocytomas/paragangliomas in Japanese subjects. PATIENTS AND METHODS: For this study, 74 unrelated patients with pheochromocytoma/paraganglioma who tested negative for mutations and deletions in RET, VHL, SDHB and SDHD were recruited through a multi-institutional collaborative effort in Japan. The TMEM127 gene sequence was determined in their germline DNA, and tumour DNA was analysed for the loss of heterozygosity. In addition, their TMEM127 gene sequences were compared with sequences from 114 normal healthy, ethnically matched controls. RESULTS: Among the 74 eligible patients, two unrelated patients (2·7%) with bilateral adrenal pheochromocytoma were found to have an identical germline TMEM127 mutation (c.116_119delTGTC, p.Ile41ArgfsX39) associated with 2q deletion loss of heterozygosity, which was also previously described in a Brazilian case (Journal of the American Medical Association, 2004, 292, 943). We also determined that none of the 114 normal healthy controls had this deletion mutation. CONCLUSION: This is the first report showing that TMEM127 mutation plays a pathological role in pheochromocytoma in an Asian population. Although our surveillance is limited, the prevalence and the phenotype of this gene mutation appear to be similar to those reported in previous studies.


Assuntos
Mutação em Linhagem Germinativa/genética , Proteínas de Membrana/genética , Feocromocitoma/genética , Adulto , Predisposição Genética para Doença/genética , Humanos , Japão , Perda de Heterozigosidade/genética , Masculino , Pessoa de Meia-Idade , Mutação
15.
PLoS One ; 17(7): e0270864, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35881638

RESUMO

All healthcare professionals must understand information on a patient's biophysical functions, and it is important to educate professionals on how to use this information in an interprofessional team for diagnosis. However, there is little interprofessional education for students of medical technology and radiological science involved in biophysical function diagnosis. In the present study, we developed a case-based interprofessional learning tool for using biophysical information for diagnosis. The study examined the effects of a collaborative exercise workshop for healthcare professional students using the tool. Participants were 234 students from three healthcare professions (medical technology, radiological science, and physical therapy). They completed the Japanese version of the Readiness for Interprofessional Learning Scale before and after the workshops. The workshops incorporated digital materials that allowed students to examine the test results of a virtual patient, answer questions, and discuss their diagnoses and prognoses. For analysis, a two-way analysis of variance was performed on the total score on the Readiness for Interprofessional Learning Scale of the three departments, and the effectiveness of the workshop for the three departments was compared. Statistical analyses showed no interaction between time and department (p = 0.283). After the workshop, students from all three departments showed significant improvements in total scores on the Readiness for Interprofessional Learning Scale (p < 0.01) with medium to large effect sizes (r = 0.33-0.52). In the comparison between departments, there was a significant difference in the awareness levels of only medical technology and radiological science students before the workshop (p = 0.015). This study conducted case-based learning workshops with students from three departments, in which a patient's biophysical information was conveyed between occupational practices. The workshops improved the awareness of interprofessional education in students from all departments and revealed that interprofessional education is important for healthcare professions involved in biophysical function diagnosis.


Assuntos
Estudantes de Ciências da Saúde , Estudantes de Medicina , Atitude do Pessoal de Saúde , Comportamento Cooperativo , Humanos , Relações Interprofissionais , Aprendizagem , Modalidades de Fisioterapia , Inquéritos e Questionários , Tecnologia Radiológica
16.
Biochim Biophys Acta Mol Basis Dis ; 1868(4): 166339, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35017029

RESUMO

The pancreatic islet vasculature is of fundamental importance to the ß-cell response to obesity-associated insulin resistance. To explore islet vascular alterations in the pathogenesis of type 2 diabetes, we evaluated two insulin resistance models: ob/ob mice, which sustain large ß-cell mass and hyperinsulinemia, and db/db mice, which progress to diabetes due to secondary ß-cell compensation failure for insulin secretion. Time-dependent changes in islet vasculature and blood flow were investigated using tomato lectin staining and in vivo live imaging. Marked islet capillary dilation was observed in ob/ob mice, but this adaptive change was blunted in db/db mice. Islet blood flow volume was augmented in ob/ob mice, whereas it was reduced in db/db mice. The protein concentrations of total and phosphorylated endothelial nitric oxide synthase (eNOS) at Ser1177 were increased in ob/ob islets, while they were diminished in db/db mice, indicating decreased eNOS activity. This was accompanied by an increased retention of advanced glycation end-products in db/db blood vessels. Amelioration of diabetes by Elovl6 deficiency involved a restoration of capillary dilation, blood flow, and eNOS phosphorylation in db/db islets. Our findings suggest that the disability of islet capillary dilation due to endothelial dysfunction impairs local islet blood flow, which may play a role in the loss of ß-cell function and further exacerbate type 2 diabetes.


Assuntos
Vasos Sanguíneos/metabolismo , Ilhotas Pancreáticas/fisiologia , Animais , Velocidade do Fluxo Sanguíneo , Diabetes Mellitus Tipo 2/patologia , Modelos Animais de Doenças , Elongases de Ácidos Graxos/deficiência , Elongases de Ácidos Graxos/genética , Feminino , Produtos Finais de Glicação Avançada/metabolismo , Insulina/metabolismo , Resistência à Insulina , Ilhotas Pancreáticas/anatomia & histologia , Ilhotas Pancreáticas/irrigação sanguínea , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Óxido Nítrico Sintase Tipo III/metabolismo , Fosforilação
17.
iScience ; 24(12): 103446, 2021 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-34988390

RESUMO

KLF15 is a transcription factor that plays an important role in the activation of gluconeogenesis from amino acids as well as the suppression of lipogenesis from glucose. Here we identified the transcription start site of liver-specific KLF15 transcript and showed that FoxO1/3 transcriptionally regulates Klf15 gene expression by directly binding to the liver-specific Klf15 promoter. To achieve this, we performed a precise in vivo promoter analysis combined with the genome-wide transcription-factor-screening method "TFEL scan", using our original Transcription Factor Expression Library (TFEL), which covers nearly all the transcription factors in the mouse genome. Hepatic Klf15 expression is significantly increased via FoxOs by attenuating insulin signaling. Furthermore, FoxOs elevate the expression levels of amino acid catabolic enzymes and suppress SREBP-1c via KLF15, resulting in accelerated amino acid breakdown and suppressed lipogenesis during fasting. Thus, the FoxO-KLF15 pathway contributes to switching the macronutrient flow in the liver under the control of insulin.

18.
Cancers (Basel) ; 13(16)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34439168

RESUMO

The high incidence of germline variants in pheochromocytoma and paraganglioma (PPGL) has been reported mainly in Europe, but not among Japanese populations in Asia. We aimed to study the prevalence of germline variants in Japanese PPGL patients and the genotype-phenotype correlation. We examined 370 PPGL probands, including 43 patients with family history and/or syndromic presentation and 327 patients with apparently sporadic (AS) presentation. Clinical data and blood samples were collected, and the seven major susceptibility genes (MAX, SDHB, SDHC, SDHD, TMEM127, VHL, and RET) were tested using Sanger sequencing. Overall, 120/370 (32.4%) patients had pathogenic or likely pathogenic variants, with 81/327 (24.8%) in AS presentation. SDHB was the most frequently mutated gene (57, 15.4%), followed by SDHD (27, 7.3%), and VHL (18, 4.9%). The incidence of metastatic PPGL was high in SDHB carriers (21/57, 36.8%). A few unique recurrent variants (SDHB c.137G>A and SDHB c.470delT) were detected in this Japanese cohort, highlighting ethnic differences. In summary, almost a quarter of patients with apparently sporadic PPGL in Japan harboured germline variants of the targeted genes. This study reinforces the recommendation in Western guidelines to perform genetic testing for PPGL and genotype-based clinical decision-making in the Japanese population.

19.
Biomedicines ; 8(3)2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32164328

RESUMO

The aim of this study was to clarify degradation characteristics in each tissue of the knee complex of a medial meniscectomy (MMx)-induced knee osteoarthritis (KOA) animal model using classical methods and an alternative comprehensive evaluation method called contrast-enhanced X-ray micro-computed tomography (CEX-µCT), which was developed in the study. Surgical MMx was performed in the right knee joints of five male Wistar rats to induce KOA. At four weeks post-surgery, the synovitis was evaluated using quantitative polymerase chain reaction (qPCR). Degradations of the articular cartilage of the tibial plateau were evaluated using classical methods and CEX-µCT. Evaluation of the synovitis demonstrated significantly increased expression levels of inflammation-associated marker genes in MMx-treated knees compared with those in sham-treated knees. Evaluation of the articular cartilage using classical methods showed that MMx fully induced degradation of the cartilage. Evaluation using CEX-µCT showed that local areas of the medial cartilage of the tibial plateau were significantly reduced in MMx-treated knees compared with those in sham-treated knees. On the other hand, total cartilage volumes were significantly increased in MMx-treated knees. On the basis of the findings of this study, the method could be relevant to study new treatments in KOA research.

20.
PeerJ ; 8: e8595, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32140302

RESUMO

BACKGROUND: With the rapid progress of genetic engineering and gene therapy methods, the World Anti-Doping Agency has raised concerns regarding gene doping, which is prohibited in sports. However, there is no standard method available for detecting transgenes delivered by injection of naked plasmids. Here, we developed a detection method for detecting transgenes delivered by injection of naked plasmids in a mouse model that mimics gene doping. METHODS: Whole blood from the tail tip and one piece of stool were used as pre-samples of injection. Next, a plasmid vector containing the human erythropoietin (hEPO) gene was injected into mice through intravenous (IV), intraperitoneal (IP), or local muscular (IM) injection. At 1, 2, 3, 6, 12, 24, and 48 h after injection, approximately 50 µL whole blood was collected from the tail tip. One piece of stool was collected at 6, 12, 24, and 48 h. From each sample, total DNA was extracted and transgene fragments were analyzed by Taqman quantitative PCR (qPCR) and SYBR green qPCR. RESULTS: In whole blood DNA samples evaluated by Taqman qPCR, the transgene fragments were detected at all time points in the IP sample and at 1, 2, 3, 6, and 12 h in the IV and IM samples. In the stool-DNA samples, the transgene fragments were detected at 6, 12, 24, and 48 h in the IV and IM samples by Taqman qPCR. In the analysis by SYBR green qPCR, the transgene fragments were detected at some time point in both specimens; however, many non-specific amplicons were detected. CONCLUSIONS: These results indicate that transgene fragments evaluated after each injection method of naked plasmids were detected in whole-blood and stool DNA samples. These findings may facilitate the development of methods for detecting gene doping.

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