Activation of AMP-activated protein kinase by metformin induces protein acetylation in prostate and ovarian cancer cells

AMP-activated protein kinase (AMPK) is an energy sensor and master regulator of metabolism. AMPK functions as a fuel gauge monitoring systemic and cellular energy status. Activation of AMPK occurs when the intracellular AMP/ATP ratio increases and leads to a metabolic switch from anabolism to catabolism. AMPK phosphorylates and inhibits acetyl-CoA carboxylase (ACC), which catalyzes carboxylation of acetyl-CoA to malonyl-CoA, the first and rate-limiting reaction in de novo synthesis of fatty acids. AMPK thus regulates homeostasis of acetyl-CoA, a key metabolite at the crossroads of metabolism, signaling, chromatin structure, and transcription. Nucleocytosolic concentration of acetyl-CoA affects histone acetylation and links metabolism and chromatin structure. Here we show that activation of AMPK with the widely used antidiabetic drug metformin or with the AMP mimetic 5-aminoimidazole-4-carboxamide ribonucleotide increases the inhibitory phosphorylation of ACC and decreases the conversion of acetyl-CoA to malonyl-CoA, leading to increased protein acetylation and altered gene expression in prostate and ovarian cancer cells. Direct inhibition of ACC with allosteric inhibitor 5-(tetradecyloxy)-2-furoic acid also increases acetylation of histones and non-histone proteins. Because AMPK activation requires liver kinase B1, metformin does not induce protein acetylation in liver kinase B1-deficient cells. Together, our data indicate that AMPK regulates the availability of nucleocytosolic acetyl-CoA for protein acetylation and that AMPK activators, such as metformin, have the capacity to increase protein acetylation and alter patterns of gene expression, further expanding the plethora of metformin's physiological effects

Homocysteine plasma levels as a marker of clinical severity in septic patients

OBJECTIVE: Homocysteine and sepsis are both associated with inflammation and endothelial activation. Therefore this study was aimed to evaluate if the plasma homocystein level is related with the septic patient clinical severity. METHODS: Severe sepsis or septic shock patients, with less than 48 hours from organ dysfunction start, were admitted to this prospective observational study. Homocysteine levels were determined by the time of study admission and then on the Days 3, 7 and 14. The homocysteine association with the Sequential Organ Failure Assessment (SOFA) score was evaluated using the Sperman test, and its association with mortality using the Mann-Whitney test. A p<0.05 value was considered statistically significant. RESULTS: Twenty one patients were enrolled, and 60 blood samples were collected to measure total homocysteine [median 6.92 (5.27 - 9.74 μmol/L)]. The Sperman correlation test showed no association between homocysteine and SOFA ( r=0.15 and p=0.26). Also no correlation was found for the homocysteine level by the study admission time and the difference between the Day 3 SOFA score versus by study admission (deltaSOFA) (r=0.04 and p=0.87). Homocysteine variation between the Day 3 and the study admission (deltaHmc) and SOFA score variation in the same period were not correlated (r=-0.11 and p=0.66). Homocysteine by the study admission was not correlated with death in intensive care unit rate (p= 0.46) or in-hospital death rate (p = 0.13). This was also true for deltaHmc (p=0.12 and p=0.99, respectively). CONCLUSION: Baseline homocysteine levels and its variations within the first dysfunction days were not related with septic patients' worsened organ function parameters or mortality.OBJETIVO: Homocisteína e a sepse estão ambos associados à inflamação e ativação endotelial. O objetivo desse estudo foi verificar se o nível plasmático de homocisteína está relacionado à gravidade do quadro séptico. MÉTODOS: Estudo clínico, prospectivo e observacional, incluindo pacientes com sepse grave ou choque séptico com menos de 48 horas de instalação da disfunção orgânica. Os níveis de homocisteína foram determinados no dia da inclusão no estudo e nos dias 3, 7, 14. A associação entre homocisteína com o escore Sequential Organ Failure Assessment (SOFA) foi avaliada pelo teste de Sperman e com mortalidade pelo teste de Mann-Whitney. Os resultados foram considerados significativos se p<0,05. RESULTADOS: Foram incluídos 21 pacientes e feitas 60 coletas para avaliação da homocisteina total (mediana de 6,92 (5,27 - 9,74 μmol/l). O teste de correlação Spearman não mostrou associação entre homocisteina e SOFA (r = -0,15 e p = 0,26). Também não foi encontrada correlação da medida de homocisteína na data de admissão do estudo e a diferença do SOFA obtido no 3º dia e o SOFA da admissão (deltaSOFA) (r = 0,04 e p = 0,87). A variação da homocisteína do 3º dia e a admissão no estudo (deltaHmc) e a variação do SOFA no mesmo período não estavam correlacionadas (r = -0,11 e p = 0,66). A homocisteina da admissão não se correlacionou com mortalidade na UTI (p=0,46) ou com a mortalidade hospitalar.(p=0,13). Mesmo quando foi utilizado o deltaHmc não houve correlação (p=012 e p=0,99, respectivamente). CONCLUSÃO: O nível basal de homocisteína ou sua variação nos primeiros dias da disfunção não estiveram relacionadas com a piora dos parâmetros funcionais dos sistemas orgânicos ou mortalidade nos pacientes sépticos.Universidade Federal de São Paulo (UNIFESP) Setor de Terapia Intensiva da Disciplina de Anestesiologia, Dor e Terapia IntensivaUniversidade Federal de São Paulo (UNIFESP)UNIFESP, Setor de Terapia Intensiva da Disciplina de Anestesiologia, Dor e Terapia IntensivaUNIFESPSciEL

Defining phenotypic and functional heterogeneity of glioblastoma stem cells by mass cytometry

Most patients with glioblastoma (GBM) die within 2 years. A major therapeutic goal is to target GBM stem cells (GSCs), a subpopulation of cells that contribute to treatment resistance and recurrence. Since their discovery in 2003, GSCs have been isolated using single-surface markers, such as CD15, CD44, CD133, and α6 integrin. It remains unknown how these single-surface marker-defined GSC populations compare with each other in terms of signaling and function and whether expression of different combinations of these markers is associated with different functional capacity. Using mass cytometry and fresh operating room specimens, we found 15 distinct GSC subpopulations in patients, and they differed in their MEK/ERK, WNT, and AKT pathway activation status. Once in culture, some subpopulations were lost and previously undetectable ones materialized. GSCs that highly expressed all 4 surface markers had the greatest self-renewal capacity, WNT inhibitor sensitivity, and in vivo tumorigenicity. This work highlights the potential signaling and phenotypic diversity of GSCs. Larger patient sample sizes and antibody panels are required to confirm these findings

Homocysteine levels and molecular analysis in congenital heart defects patients

BV UNIFESP: Teses e dissertaçõe

Evaluation of oxidative stress markers and cardiovascular risk factors in Fabry Disease patients

Fabry Disease, an X-linked inborn error of metabolism, is characterized by progressive renal insufficiency, with cardio and cerebrovascular involvement. Homocysteine (Hcy) is considered a risk factor for vascular diseases, but the mechanisms by which it produces cardiovascular damage are still poorly understood. Regarding the vascular involvement in FD patients, the analysis of factors related to thromboembolic events could be useful to improving our understanding of the disease. The aim of this study was to evaluate plasma Hcy and other parameters involved in the methionine cycle, as well as oxidative stress markers. The sample consisted of a group of 10 male FD patients and a control group of 8 healthy individuals, paired by age. Venous blood was collected for Hcy determination, molecular analysis, identification of thiobarbituric acid reactive substances, total glutathione and antioxidant enzymes activity, as well as vitamins quantification. Comparative analysis of FD patients versus the control group indicated hyperhomocysteinemia in 8 of the 10 FD patients, as well as a significant increase in overall glutathione levels and catalase activity. It is inferred that FD patients, apart from activation of the antioxidant system, present increased levels of plasma Hcy, although this is probably unrelated to common alterations in the methionine cycle

Evaluation of oxidative stress markers and cardiovascular risk factors in Fabry Disease patients

Fabry Disease, an X-linked inborn error of metabolism, is characterized by progressive renal insufficiency, with cardio and cerebrovascular involvement. Homocysteine (Hcy) is considered a risk factor for vascular diseases, but the mechanisms by which it produces cardiovascular damage are still poorly understood. Regarding the vascular involvement in FD patients, the analysis of factors related to thromboembolic events could be useful to improving our understanding of the disease. The aim of this study was to evaluate plasma Hcy and other parameters involved in the methionine cycle, as well as oxidative stress markers. The sample consisted of a group of 10 male FD patients and a control group of 8 healthy individuals, paired by age. Venous blood was collected for Hcy determination, molecular analysis, identification of thiobarbituric acid reactive substances, total glutathione and antioxidant enzymes activity, as well as vitamins quantification. Comparative analysis of FD patients versus the control group indicated hyperhomocysteinemia in 8 of the 10 FD patients, as well as a significant increase in overall glutathione levels and catalase activity. It is inferred that FD patients, apart from activation of the antioxidant system, present increased levels of plasma Hcy, although this is probably unrelated to common alterations in the methionine cycle

Oxidative stress markers in patients with inborn errors of metabolism

Univ Fed Sao Paulo, UNIFESP EPM, Ctr Referencia Erros Inatos Metab, Dept Pediat, Sao Paulo, BrazilUniv Fed Sao Paulo, UNIFESP EPM, Ctr Referencia Erros Inatos Metab, Dept Pediat, Sao Paulo, BrazilWeb of Scienc

Increased concentration of plasma homocysteine in children with systemic lupus erythematosus

ObjectiveStudies in adults with SLE have evidenced increase of homocysteine related, mainly, to thromboembolic events. The aim of our study was to evaluate plasma homocysteine concentration in children with systemic lupus erythematosus (SLE) and its correlation with renal involvement, serum and erythrocyte folate, vitamin B12, antiphospholipid antibodies, estimated creatinine clearance and dyslipidemia.MethodsThirty-two children (29 females) with SLE and 32 healthy controls (29 females) matched for age and sex were included in the study. The mean age of patients and controls was 14.2 years (range from 10 to 18 years). Only one patient presented one thrombotic event. Plasma homocysteine, erythrocyte and serum folate, vitamin B12, lipid profile, antiphospholipid antibodies and estimated creatinine clearance were evaluated. Raised homocysteine concentration was defined as equal or more than 12.9 mol/L.ResultsRaised homocysteine concentration was detected in 15 (46.9%) children with SLE with an important statistical difference in relation to control group (p < 0.001). A positive correlation was found between plasma homocysteine concentration and renal involvement (odds ratio 11.1 [95% CI 1.50-82.24], p = 0.01) based on the presence of renal biopsy, abnormalities of urine sediment and/or serum creatinine. However when we performed the estimated creatinine clearance the correlation with homocysteine concentration was not positive. We did not observe abnormalities in serum and erythrocyte folate and vitamin B12 in our patients. However they presented significant higher concentrations of TC total cholesterol (p = 0.005) and of LDL low-density lipoprotein (p = 0.02) than controls.ConclusionsElevated plasma homocysteine concentration is frequent in children with SLE. We believe that these results may signalize to the possibility of complications in our patients later in life. Further long-term and prospective studies are needed in order to determine the real role of the homocysteine concentration as a risk factor in children.Univ Fed Sao Paulo, Dept Pediat, Sao Paulo, BrazilUniv Sao Paulo, Fac Pharmaceut Sci, Dept Clin Chem & Toxicol, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Pediat, Sao Paulo, BrazilWeb of Scienc