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In the mdx mice model of Duchenne Muscular Dystrophy (DMD), mild endurance exercise training positively affected limb skeletal muscles, whereas few and controversial data exist on the effects of training on the diaphragm. The diaphragm was examined in mdx (C57BL/10ScSn-Dmd mdx) and wild-type (WT, C57BL/10ScSc) mice under sedentary conditions ( mdx-SD, WT-SD) and during mild exercise training ( mdx-EX, WT-EX). At baseline, and after 30 and 45 days (training: 5 d/wk for 6 weeks), diaphragm muscle morphology and Cx39 protein were assessed. In addition, tissue levels of the chaperonins Hsp60 and Hsp70 and the p65 subunit of nuclear factor-kB (NF-kB) were measured in diaphragm, gastrocnemius, and quadriceps in each experimental group at all time points. Although morphological analysis showed unchanged total area of necrosis/regeneration in the diaphragm after training, there was a trend for larger areas of regeneration than necrosis in the diaphragm of mdx-EX compared to mdx-SD mice. However, the levels of Cx39, a protein associated with active regeneration in damaged muscle, were similar in the diaphragm of mdx-EX and mdx-SD mice. Hsp60 significantly decreased at 45 days in the diaphragm, but not in limb muscles, in both trained and sedentary mdx compared to WT mice. In limb muscles, but not in the diaphragm, Hsp70 and NF-kB p65 levels were increased in mdx mice irrespective of training at 30 and 45 days. Therefore, the diaphragm of mdx mice showed little inflammatory and stress responses over time, and appeared hardly affected by mild endurance training. J. Cell. Physiol. 232: 2044-2052, 2017. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Mild exercise training may positively affect the course of Duchenne Muscular Dystrophy (DMD). Training causes mild bronchial epithelial injury in both humans and mice, but no study assessed the effects of exercise in mdx mice, a well known model of DMD. The airway epithelium was examined in mdx (C57BL/10ScSn-Dmdmdx) mice, and in wild type (WT, C57BL/10ScSc) mice either under sedentary conditions ( mdx-SD, WT-SD) or during mild exercise training (mdx-EX, WT-EX). At baseline, and after 30 and 45 days of training (5 d/wk for 6 weeks), epithelial morphology and markers of regeneration, apoptosis, and cellular stress were assessed. The number of goblet cells in bronchial epithelium was much lower in mdx than in WT mice under all conditions. At 30 days, epithelial regeneration (PCNA positive cells) was higher in EX than SD animals in both groups; however, at 45 days, epithelial regeneration decreased in mdx mice irrespective of training, and the percentage of apoptotic (TUNEL positive) cells was higher in mdx-EX than in WT-EX mice. Epithelial expression of HSP60 (marker of stress) progressively decreased, and inversely correlated with epithelial apoptosis (r = −0.66, P = 0.01) only in mdx mice. Lack of dystrophin in mdx mice appears associated with defective epithelial differentiation, and transient epithelial regeneration during mild exercise training. Hence, lack of dystrophin might impair repair in bronchial epithelium, with potential clinical consequences in DMD patients. J. Cell. Physiol. 231: 2218-2223, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptor gamma coactivator-1α ( PGC-1α) is a transcriptional coactivator involved in the regulation of mitochondrial biogenesis and cell defense. The functions of PGC-1α in physiology of brain mitochondria are, however, not fully understood. To address this we have studied wild-type and transgenic mice with a two-fold overexpression of PGC-1α in brain neurons. Data showed that the relative number and basal respiration of brain mitochondria were increased in PGC-1α transgenic mice compared with wild-type mitochondria. These changes occurred concomitantly with altered levels of proteins involved in oxidative phosphorylation ( OXPHOS) as studied by proteomic analyses and immunoblottings. Cultured hippocampal neurons from PGC-1α transgenic mice were more resistant to cell degeneration induced by the glutamate receptor agonist kainic acid. In vivo kainic acid induced excitotoxic cell death in the hippocampus at 48 h in wild-type mice but significantly less so in PGC-1α transgenic mice. However, at later time points cell degeneration was also evident in the transgenic mouse hippocampus, indicating that PGC-1α overexpression can induce a delay in cell death. Immunoblotting showed that X-linked inhibitor of apoptosis protein ( XIAP) was increased in PGC-1α transgenic hippocampus with no significant changes in Bcl-2 or Bcl-X. Collectively, these results show that PGC-1α overexpression contributes to enhanced neuronal viability by stimulating mitochondria number and respiration and increasing levels of OXPHOS proteins and the anti-apoptotic protein XIAP. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction and oxidative stress occur in Parkinson's disease (PD), but little is known about the molecular mechanisms controlling these events. Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) is a transcriptional coactivator that is a master regulator of oxidative stress and mitochondrial metabolism. We show here that transgenic mice overexpressing PGC-1α in dopaminergic neurons are resistant against cell degeneration induced by the neurotoxin MPTP. The increase in neuronal viability was accompanied by elevated levels of mitochondrial antioxidants SOD2 and Trx2 in the substantia nigra of transgenic mice. PGC-1α overexpression also protected against MPTP-induced striatal loss of dopamine, and mitochondria from PGC-1α transgenic mice showed an increased respiratory control ratio compared with wild-type animals. To modulate PGC-1α, we employed the small molecular compound, resveratrol (RSV) that protected dopaminergic neurons against the MPTP-induced cell degeneration almost to the same extent as after PGC-1α overexpression. As studied in vitro, RSV activated PGC-1α in dopaminergic SN4741 cells via the deacetylase SIRT1, and enhanced PGC- 1α gene transcription with increases in SOD2 and Trx2. Taken together, the results reveal an important function of PGC-1α in dopaminergic neurons to combat oxidative stress and increase neuronal viability. RSV and other compounds acting via SIRT1/PGC-1α may prove useful as neuroprotective agents in PD and possibly in other neurological disorders. [ABSTRACT FROM AUTHOR]

Abstract: In the present study we aimed to verify if the enhancement of glial cell line-derived neurotrophic factor (GDNF) production in mouse striatum following treatment with LY379268 may also induce in the nigrostriatal system a time-related activation of RET receptor and its specific intracellular signaling. For this purpose, we have investigated the effects of LY379268 treatment on RET phosphorylation at the Tyr1062 and on downstream signaling Erk1/2, Akt and PLCγ1 pathway activation. The results showed that treatment with LY379268 (3 mg/kg) induces a significant increase of GDNF levels and time-related RET and Erk1/2 phosphorylation in the striatum. These increases were detected at 24 h and 48 h following LY379268 treatment. No changes were observed in the Akt and PLCγ1 phosphorylation levels. Similar results for p-Erk1/2 were observed in the substantia nigra. A complete block of LY379268 effect on striatal RET and p-Erk1/2 phosphorylation was observed in mice intrastriatal injected with anti-GDNF antibodies, suggesting a correlation between GDNF upregulation and RET activation. Overall, with present data we have shown that activation of mGluR2/3 receptors by LY379268 may be particularly promising for nigrostriatal dopaminergic system protection by enhancing striatal levels of GDNF/RET trophic system activity. [Copyright &y& Elsevier]

Abstract: Aims: We investigated the effects induced by exogenous adenosine on the spontaneous contractile activity of the longitudinal muscle of a mouse ileum, the receptor subtypes activated, the involvement of enteric nerves and whether opening of K+ channels was a downstream event leading to the observed effects. Main methods: Mechanical responses of the mouse ileal longitudinal muscle to adenosine were examined in vitro as changes in isometric tension. Key findings: Adenosine caused a concentration-dependent reduction of the spontaneous contraction amplitude of the ileal longitudinal muscle up to its complete disappearance. This effect induced was markedly reduced by an A1 receptor antagonist, but not by A2 and A3 receptor antagonists and mimicked only by the A1 receptor agonist. Adenosine uptake inhibitors did not change adenosine potency. A1 receptor expression was detected at the smooth muscle level. Adenosine responses were insensitive to tetrodotoxin, atropine or nitric oxide synthase inhibitor. Tetraethylammonium and iberiotoxin, BKCa channel blockers, significantly reduced adenosine effects, whilst 4-aminopyridine, a Kv blocker, apamin, a small conductance Ca2+-activated K+ (SKCa) channel blocker, charybdotoxin, an intermediate conductance Ca2+-activated K+ (IKCa) and BKCa channel blocker, or glibenclamide, an ATP-sensitive K+ channel blocker, had no effects. The combination of apamin plus iberiotoxin caused a reduction of the purinergic effects greater than iberiotoxin alone. Significance: Adenosine acts as an inhibitory modulator of the contractility of mouse ileal longitudinal muscle through postjunctional A1 receptors, which in turn would induce opening of BKCa and SKCa potassium channels. This study would provide new insight in the pharmacology of purinergic receptors involved in the modulation of the gastrointestinal contractility. [Copyright &y& Elsevier]

Abstract: Although connexin36 (Cx36) has been studied in several tissues, it is notable that no data are available on Cx36 expression in the carotid body and the intestine. The present study was undertaken to evaluate using immunohistochemistry, PCR and Western blotting procedures, whether Cx36 was expressed in the mouse carotid body and in the intestine at ileum and colon level. In the carotid body, Cx36 was detected as diffuse punctate immunostaining and as protein by Western blotting and mRNA by RT-PCR. Cx36 punctate immunostaining was also evident in the intestine with localization restricted to the myenteric plexus of both the ileum and the colon, and this detection was also confirmed by Western blotting and RT-PCR. All the data obtained were validated using Cx36 knockout mice. Taken together the present data on localization of Cx36 gap-junctions in two tissues of neural crest-derived neuroendocrine organs may provide an anatomical basis for future functional investigations. [Copyright &y& Elsevier]

Abstract: Treatment with resveratrol (RSV) has been shown to protect vulnerable neurons after various brain injuries and in neurodegenerative diseases. The mechanisms for the effects of RSV in brain are not fully understood, but RSV may affect the expression of various gene products. RSV is structurally related to the synthetic estrogen, diethylstilbestrol so the effects of RSV may be gender-specific. Here we studied the role of RSV in the regulation of dopamine transporter (DAT) in the striatum using male and female mice. The basic levels of DAT in the striatum showed no sex difference, but the levels increased significantly by RSV (20 mg/kg i.p.) in female but not in male mice. Pretreatment of mice with the selective estrogen receptor (ER), ERα- and ERβ antagonist ICI 182,780, led to a complete block of RSV effect on DAT protein levels, suggesting that ERs are involved in the up-regulation of DAT by RSV. Similar data was also obtained in culture using human MESC2.10 and mouse SN4741 dopaminergic cells after treatment with RSV. Data further showed that RSV specifically induced gene transcription of DAT in the dopaminergic cells. These results show that estrogen receptors are involved in the up-regulation of DAT by RSV in the dopaminergic neurons, demonstrating a sex-dependent effect of RSV in the brain that may be of clinical importance. This article is part of a Special Issue entitled ‘Post-Traumatic Stress Disorder’. [Copyright &y& Elsevier]

Abstract: Adenine-based purines play a pivotal role in the control of gastrointestinal motility in rodents. Recently, guanine-based purines have been also shown to exert extracellular effects in the central nervous system raising the possibility of the existence of distinct receptors for guanine-based purines. Thus, it seems likely to speculate that also guanine-based purines may play a role in the modulation of the intestinal contractility. Spontaneous and neurally-evoked mechanical activity was recorded in vitro as changes in isometric tension in circular muscle strips from mouse distal colon. Guanosine up to 3mM or guanine up to 1mM failed to affect the spontaneous mechanical activity, but reduced the amplitude of the electrical field stimulation (EFS)-induced cholinergic contractions, without affecting the early nitrergic relaxation. Both compounds failed to affect the direct contractile responses evoked by carbachol. No desensitization of the response was observed. Guanine-based purine effects were not altered by theophylline, P1 purinoceptor antagonist, by PPADS or suramin, P2 purinoceptor antagonists, by ODQ, guanilyl cyclase inhibitor, or by DDA, adenylyl cyclase inhibitor. Nucleoside uptake inhibitors, dipyridamole or 6-[(4-Nitrobenzyl)thio]-9-β-D-ribofuranosylpurine (NBTI), antagonized the inhibitory effects induced by guanosine without interfering with guanine. On the contrary, adenine, a competitive inhibitor of nucleobase uptake, antagonized guanine-induced effects. In conclusion, our data indicate that guanosine and guanine are able to modulate negatively the excitatory cholinergic neurotransmission in the circular muscle layer of mouse colon. Guanine-based purines appear to interfere with prejunctional acethylcoline release. Their effects are dependent by their cellular uptake, and independent by adenine-based purine receptors. [ABSTRACT FROM AUTHOR]