Global liver proteomic analysis of Wistar rats chronically exposed to low-levels of bisphenol A and S.

Exposure to bisphenol A (BPA) and bisphenol S (BPS) has been associated with the development of metabolic disorders, such as obesity, dyslipidemias, and nonalcoholic fatty liver disease. Nonetheless, the associated mechanisms are still not fully understood. BPS is being used with no restrictions to replace BPA, which increases the concern regarding its safety and claims for further investigation on its potential mechanisms of toxicity. The present study aims to access liver molecular disturbances which could be associated with systemic metabolic disorders following exposure to BPA or BPS. Therefore, body weight gain and serum biochemical parameters were measured in male Wistar rats chronically exposed to 50 or 500 µg/kg/day of BPA or BPS, while an extensive evaluation of liver protein expression changes was conducted after exposure to 50 µg/kg/day of both compounds. Exposure to the lowest dose of BPA led to the development of hyperglycemia and hypercholesterolemia, while the BPS lowest dose led to the development of hypertriglyceridemia. Besides, exposure to 500 µg/kg/day of BPS significantly increased body weight gain and LDL-cholesterol levels. Hepatic proteins differentially expressed in BPA and BPS-exposed groups compared to the control group were mostly related to lipid metabolism and synthesis, with upregulation of glucokinase activity-related sequence 1 (1.8-fold in BPA and 2.4-fold in BPS), which is involved in glycerol triglycerides synthesis, and hydroxymethylglutaryl-CoA synthase cytoplasmic (2-fold in BPS), an enzyme involved in mevalonate biosynthesis. Essential mitochondrial proteins of the electron transport chain were upregulated after exposure to both contaminants. Also, BPA and BPS dysregulated expression of liver antioxidant enzymes, which are involved in cellular reactive oxygen species detoxification. Altogether, the results of the present study contribute to expand the scientific understanding of how BPA and BPS lead to the development of metabolic disorders and reinforce the risks associated with exposure to these contaminants.

The highly efficient powerhouse in the Wistar audiogenic rat, an epileptic rat strain.

The Wistar audiogenic rat (WAR) is an animal model of tonic-clonic epileptic seizures, developed after genetic selection by sister × brother inbreeding of Wistar rats susceptible to sound stimuli. Although metabolic changes have been described in this strain, nothing is known about its mitochondrial metabolism. Here, we addressed mitochondrial aspects of oxidative phosphorylation, oxidative stress, biogenesis, and dynamics in liver, skeletal muscle, and heart of male WARs and correlating them with physiological aspects of body metabolism. The results showed higher mitochondrial content, respiration rates in phosphorylation and noncoupled states, and H2O2 production in WARs. Liver presented higher content of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α) and mammalian target of rapamycin, proteins related to mitochondrial biogenesis. In agreement, isolated liver mitochondria from WARs showed higher respiration rates in phosphorylation state and ADP-to-O ratio, as well as higher content of proteins related to electron transport chain ATP synthase, TCA cycle, and mitochondrial fusion and fission compared with their Wistar counterparts. Mitochondria with higher area and perimeter and more variable shapes were found in liver and soleus from WARs in addition to lower reduced-to-oxidized glutathione ratio. In vivo, WARs demonstrated lower body mass and energy expenditure but higher food and water intake and amino acid oxidation. When exposed to a running test, WARs reached higher speed and resisted for a longer time and distance than their Wistar controls. In conclusion, the WAR strain has mitochondrial changes in liver, skeletal muscle, and heart that improve its mitochondrial capacity of ATP production, making it an excellent rat model to study PGC1α overexpression and mitochondrial function in different physiological conditions or facing pathological challenges.

Energy Metabolism and Redox State in Brains of Wistar Audiogenic Rats, a Genetic Model of Epilepsy.

The Wistar Audiogenic Rat (WAR) strain is a genetic model of epilepsy, specifically brainstem-dependent tonic-clonic seizures, triggered by acute auditory stimulation. Chronic audiogenic seizures (audiogenic kindling) mimic temporal lobe epilepsy, with significant participation of the hippocampus, amygdala, and cortex. The objective of the present study was to characterize the mitochondrial energy metabolism in hippocampus and cortex of WAR and verify its relationship with seizure severity. Hippocampus of WAR naïve (no seizures) presented higher oxygen consumption in respiratory states related to the maximum capacities of phosphorylation and electron transfer system, elevated mitochondrial density, lower GSH/GSSG and catalase activity, and higher protein carbonyl and lactate contents, compared with their Wistar counterparts. Audiogenic kindling had no adding functional effect in WAR, but in Wistar, it induced the same alterations observed in the audiogenic strain. In the cortex, WAR naïve presented elevated mitochondrial density, lower GSH/GSSG and catalase activity, and higher protein carbonyl levels. Chronic acoustic stimulation in Wistar induced the same alterations in cortex and hippocampus. Mainly in the hippocampus, WAR naïve presented elevated mRNA expression of glucose, lactate and excitatory amino acids transporters, several glycolytic enzymes, lactate dehydrogenase, and Na+/K+ ATPase in neurons and in astrocytes. In vivo treatment with mitochondrial uncoupler 2,4-dinitrophenol (DNP) or N-acetylcysteine (NAC) in WAR had no effect on mitochondrial metabolism, but lowered oxidative stress. Unlike DNP, NAC downregulated all enzyme genes involved in glucose and lactate uptake, and metabolism in neurons and astrocytes. Additionally, it was able to reduce brainstem seizure severity in WAR. In conclusion, in WAR naïve animals, both cerebral cortex and hippocampus display elevated mitochondrial density and/or activity associated with oxidative damage, glucose and lactate metabolism pathways upregulation, and increased Na+/K+ ATPase mRNA expression. Only in vivo treatment with NAC was able to reduce seizure severity of kindled WARs, possibly via down regulation of glucose/lactate metabolism. Taken together, our results are a clear contribution to the field of mitochondrial metabolism associated to epileptic seizures.

Metformin exerts multitarget antileukemia activity in JAK2V617F-positive myeloproliferative neoplasms.

The recurrent gain-of-function JAK2V617F mutation confers growth factor-independent proliferation for hematopoietic cells and is a major contributor to the pathogenesis of myeloproliferative neoplasms (MPN). The lack of complete response in most patients treated with the JAK1/2 inhibitor ruxolitinib indicates the need for identifying novel therapeutic strategies. Metformin is a biguanide that exerts selective antineoplastic activity in hematological malignancies. In the present study, we investigate and compare effects of metformin and ruxolitinib alone and in combination on cell signaling and cellular functions in JAK2V617F-positive cells. In JAK2V617F-expressing cell lines, metformin treatment significantly reduced cell viability, cell proliferation, clonogenicity, and cellular oxygen consumption and delayed cell cycle progression. Metformin reduced cyclin D1 expression and RB, STAT3, STAT5, ERK1/2 and p70S6K phosphorylation. Metformin plus ruxolitinib demonstrated more intense reduction of cell viability and induction of apoptosis compared to monotherapy. Notably, metformin reduced Ba/F3 JAK2V617F tumor burden and splenomegaly in Jak2V617F knock-in-induced MPN mice and spontaneous erythroid colony formation in primary cells from polycythemia vera patients. In conclusion, metformin exerts multitarget antileukemia activity in MPN: downregulation of JAK2/STAT signaling and mitochondrial activity. Our exploratory study establishes novel molecular mechanisms of metformin and ruxolitinib action and provides insights for development of alternative/complementary therapeutic strategies for MPN.

Combretum lanceolatum flowers extract shows antidiabetic activity through activation of AMPK by quercetin

The present study evaluated the antidiabetic activity of the Combretum lanceolatum Pohl ex Eichler, Combretaceae, flowers extract (ClEtOH) in diabetic rats. Streptozotocin-diabetic rats were divided into four groups: diabetic control, diabetic treated with 500 mg/kg of metformin and diabetic treated with 250 or 500 mg/kg of ClEtOH for 21 days. The treatment of diabetic rats with 500 mg/kg of ClEtOH promoted an increase in the weight of liver, white adipose tissues and skeletal muscles, improving body weight gain. Diabetic rats treated with 500 mg/kg of ClEtOH also presented reduction in glycemia, glycosuria and urinary urea levels, and increase in liver glycogen content. HPLC chromatogram showed that quercetin is the major compound in the extract. The phosphorylation levels of adenosine monophosphate-activated protein kinase were increased in liver slices incubated in vitro with 50 µg/mL of ClEtOH, similarly to the incubation with metformin (50 µg/mL) or quercetin (10 µg/mL). The antihyperglycemic effect of ClEtOH was similar to that of metformin and appears to be through inhibition of gluconeogenesis, since urinary urea was reduced and skeletal muscle mass was increased. These data indicate that the antidiabetic activity of the Combretum lanceolatum extract could be mediated, at least in part, through activation of adenosine monophosphateactivated protein kinase by quercetin.