Improvement Of The Physical Performance Is Associated With Activation Of No/pgc-1α/mttfa Signaling Pathway And Increased Protein Expressions Of Electron Transport Chain In Gastrocnemius Muscle From Rats Supplemented With L-arginine.

To examine the influence of l-arginine supplementation in combination with physical training on mitochondrial biomarkers from gastrocnemius muscle and its relationship with physical performance. Male Wistar rats were divided into four groups: control sedentary (SD), sedentary supplemented with l-arginine (SDLA), trained (TR) and trained supplemented with l-arginine (TRLA). Supplementation of l-arginine was administered by gavage (62.5mg/ml/day/rat). Physical training consisted of 60min/day, 5days/week, 0% grade, speed of 1.2km/h. The study lasted 8weeks. Skeletal muscle mitochondrial enriched fraction as well as cytoplasmic fractions were obtained for Western blotting and biochemical analyses. Protein expressions of transcriptor coactivator (PGC-1α), transcriptor factors (mtTFA), ATP synthase subunit c, cytochrome oxidase (COXIV), constitutive nitric oxide synthases (eNOS and nNOS), Cu/Zn-superoxide dismutase (SOD) and manganese-SOD (Mn-SOD) were evaluated. We also assessed in plasma: lipid profile, glycemia and malondialdehyde (MDA) levels. The nitrite/nitrate (NOx(-)) levels were measured in both plasma and cytosol fraction of the gastrocnemius muscle. 8-week l-arginine supplementation associated with physical training was effective in promoting greater tolerance to exercise that was accompanied by up-regulation of the protein expressions of mtTFA, PGC-1α, ATP synthase subunit c, COXIV, Cu/Zn-SOD and Mn-SOD. The upstream pathway was associated with improvement of NO bioavailability, but not in NO production since no changes in nNOS or eNOS protein expressions were observed. This combination would be an alternative approach for preventing cardiometabolic diseases given that in overt diseases a profound impairment in the physical performance of the patients is observed.

Activation Of The Low Molecular Weight Protein Tyrosine Phosphatase In Keratinocytes Exposed To Hyperosmotic Stress.

Herein, we provide new contribution to the mechanisms involved in keratinocytes response to hyperosmotic shock showing, for the first time, the participation of Low Molecular Weight Protein Tyrosine Phosphatase (LMWPTP) activity in this event. We reported that sorbitol-induced osmotic stress mediates alterations in the phosphorylation of pivotal cytoskeletal proteins, particularly Src and cofilin. Furthermore, an increase in the expression of the phosphorylated form of LMWPTP, which was followed by an augment in its catalytic activity, was observed. Of particular importance, these responses occurred in an intracellular milieu characterized by elevated levels of reduced glutathione (GSH) and increased expression of the antioxidant enzymes glutathione peroxidase and glutathione reductase. Altogether, our results suggest that hyperosmostic stress provides a favorable cellular environment to the activation of LMWPTP, which is associated with increased expression of antioxidant enzymes, high levels of GSH and inhibition of Src kinase. Finally, the real contribution of LMWPTP in the hyperosmotic stress response of keratinocytes was demonstrated through analysis of the effects of ACP1 gene knockdown in stressed and non-stressed cells. LMWPTP knockdown attenuates the effects of sorbitol induced-stress in HaCaT cells, mainly in the status of Src kinase, Rac and STAT5 phosphorylation and activity. These results describe for the first time the participation of LMWPTP in the dynamics of cytoskeleton rearrangement during exposure of human keratinocytes to hyperosmotic shock, which may contribute to cell death.

An Asp49 Phospholipase A2 From Snake Venom Induces Cyclooxygenase-2 Expression And Prostaglandin E2 Production Via Activation Of Nf-κb, P38mapk, And Pkc In Macrophages.

Phospholipases A2 (PLA2) are key enzymes for production of lipid mediators. We previously demonstrated that a snake venom sPLA2 named MT-III leads to prostaglandin (PG)E2 biosynthesis in macrophages by inducing the expression of cyclooxygenase-2 (COX-2). Herein, we explored the molecular mechanisms and signaling pathways leading to these MT-III-induced effects. Results demonstrated that MT-III induced activation of the transcription factor NF-κB in isolated macrophages. By using NF-κB selective inhibitors, the involvement of this factor in MT-III-induced COX-2 expression and PGE2 production was demonstrated. Moreover, MT-III-induced COX-2 protein expression and PGE2 release were attenuated by pretreatment of macrophages with SB202190, and Ly294002, and H-7-dihydro compounds, indicating the involvement of p38MAPK, PI3K, and PKC pathways, respectively. Consistent with this, MT-III triggered early phosphorylation of p38MAPK, PI3K, and PKC. Furthermore, SB202190, H-7-dihydro, but not Ly294002 treatment, abrogated activation of NF-κB induced by MT-III. Altogether, these results show for the first time that the induction of COX-2 protein expression and PGE2 release, which occur via NF-κB activation induced by the sPLA2-MT-III in macrophages, are modulated by p38MAPK and PKC, but not by PI3K signaling proteins.

Eccentric Exercise Leads To Glial Activation But Not Apoptosis In Mice Spinal Cords.

The aim of this investigation was to evaluate the effects of 3 overtraining (OT) protocols on the glial activation and apoptosis in the spinal cords of mice. Rodents were divided into control (C; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up) and overtrained by running without inclination (OTR). The incremental load test, ambulation test, exhaustive test and functional behavioural assessment were used as performance evaluation parameters. 36 h after the exhaustive test, the dorsal and ventral parts of the lumbar spinal cord (L4-L6) were dissected for subsequent protein analysis by immunoblotting. The OT protocols led to similar responses of some performance parameters. The ventral glial fibrillary acidic protein (GFAP) protein levels were diminished in the OTR/up and OTR compared to CT and OTR/down groups. The ventral ionized calcium binding adaptor molecule 1 (Iba-1), and the dorsal GFAP and Iba-1 protein levels were increased in the OTR/down compared to the other groups. The ratio between the cleaved capase-3/caspase-3 and cleaved caspase-9/caspase-9 measured in the spinal cord were not sensitive to the OT protocols. In summary, the OTR/down activated the glial cells in the motor (i. e. Iba-1) and sensory (i. e. GFAP and Iba-1) neurons without leading to apoptosis.

Increased Expression Of Hes5 Protein In Notch Signaling Pathway In The Hippocampus Of Mice Offspring Of Dams Fed A High-fat Diet During Pregnancy And Suckling.

Maternal high-fat diet (HFD) impairs hippocampal development of offspring promoting decreased proliferation of neural progenitors, in neuronal differentiation, in dendritic spine density and synaptic plasticity reducing neurogenic capacity. Notch signaling pathway participates in molecular mechanisms of the neurogenesis. The activation of Notch signaling leads to the upregulation of Hes5, which inhibits the proliferation and differentiation of neural progenitors. This study aimed to investigate the Notch/Hes pathway activation in the hippocampus of the offspring of dams fed an HFD. Female Swiss mice were fed a control diet (CD) and an HFD from pre-mating until suckling. The bodyweight and mass of adipose tissue in the mothers and pups were also measured. The mRNA and protein expression of Notch1, Hes5, Mash1, and Delta1 in the hippocampus was assessed by RT-PCR and western blotting, respectively. Dams fed the HFD and their pups had an increased bodyweight and amount of adipose tissue. Furthermore, the offspring of mothers fed the HFD exhibited an increased Hes5 expression in the hippocampus compared with CD offspring. In addition, HFD offspring also expressed increased amounts of Notch1 and Hes5 mRNA, whereas Mash1 expression was decreased. However, the expression of Delta1 did not change significantly. We propose that the overexpression of Hes5, a Notch effector, downregulates the expression of the proneural gene Mash1 in the offspring of obese mothers, delaying cellular differentiation. These results provide further evidence that an offspring's hippocampus is molecularly susceptible to maternal HFD and suggest that Notch1 signaling in this brain region is important for neuronal differentiation.