1,087 research outputs found
The weight-inclusive vs. weight-normative approach to health: Evaluating the evidence for prioritizing well-being over weight
Using an ethical lens, this review evaluates two methods of working within patient care and public health: the weight-normative approach (emphasis on weight and weight loss when defining health and well-being) and the weight-inclusive approach (emphasis on viewing health and well-being as multifaceted while directing efforts toward improving health access and reducing weight stigma). Data reveal that the weight-normative approach is not effective for most people because of high rates of weight regain and cycling from weight loss interventions, which are linked to adverse health and well-being. Its predominant focus on weight may also foster stigma in health care and society, and data show that weight stigma is also linked to adverse health and well-being. In contrast, data support a weight-inclusive approach, which is included in models such as Health at Every Size for improving physical (e.g., blood pressure), behavioral (e.g., binge eating), and psychological (e.g., depression) indices, as well as acceptability of public health messages. Therefore, the weight-inclusive approach upholds nonmaleficience and beneficience, whereas the weight-normative approach does not. We offer a theoretical framework that organizes the research included in this review and discuss how it can guide research efforts and help health professionals intervene with their patients and community
Novel cellular mechanisms for neuroprotection in ischemic preconditioning: A view from inside organelles
Ischemic preconditioning represents an important adaptation mechanism of CNS, which results in its increased tolerance to the lethal cerebral ischemia. The molecular mechanisms responsible for the induction and maintenance of ischemic tolerance in the brain are complex and not yet completely clarified. In the last 10 years, great attention has been devoted to unravel the intracellular pathways activated by preconditioning and responsible for the establishing of the tolerant phenotype. Indeed, recent papers have been published supporting the hypothesis that mitochondria might act as master regulators of preconditioning-triggered endogenous neuroprotection due to their ability to control cytosolic calcium homeostasis. More interestingly, the demonstration that functional alterations in the ability of mitochondria and endoplasmic reticulum (ER) managing calcium homeostasis during ischemia, opened a new line of research focused to the role played by mitochondria and ER cross-talk in the pathogenesis of cerebral ischemia in order to identify new molecular mechanisms involved in the ischemic tolerance. In line with these findings and considering that the expression of the three isoforms of the sodium calcium exchanger (NCX), NCX1, NCX2, and NCX3, mainly responsible for the regulation of Ca2+ homeostasis, was reduced during cerebral ischemia, it was investigated whether these proteins might play a role in neuroprotection induced by ischemic tolerance. In this review, evidence supporting the involvement of ER and mitochondria interaction within the preconditioning paradigm will be provided. In particular, the key role played by NCXs in the regulation of Ca2+-homeostasis at the different subcellular compartments will be discussed as new molecular mechanism proposed for the establishing of ischemic tolerant phenotype
The hypoxia sensitive metal transcription factor MTF-1 activates NCX1 brain promoter and participates in remote postconditioning neuroprotection in stroke
Remote limb ischemic postconditioning (RLIP) is an experimental strategy in which short femoral artery ischemia reduces brain damage induced by a previous harmful ischemic insult. Ionic homeostasis maintenance in the CNS seems to play a relevant role in mediating RLIP neuroprotection and among the effectors, the sodium-calcium exchanger 1 (NCX1) may give an important contribution, being expressed in all CNS cells involved in brain ischemic pathophysiology. The aim of this work was to investigate whether the metal responsive transcription factor 1 (MTF-1), an important hypoxia sensitive transcription factor, may (i) interact and regulate NCX1, and (ii) play a role in the neuroprotective effect mediated by RLIP through NCX1 activation. Here we demonstrated that in brain ischemia induced by transient middle cerebral occlusion (tMCAO), MTF-1 is triggered by a subsequent temporary femoral artery occlusion (FAO) and represents a mediator of endogenous neuroprotection. More importantly, we showed that MTF-1 translocates to the nucleus where it binds the metal responsive element (MRE) located at −23/−17 bp of Ncx1 brain promoter thus activating its transcription and inducing an upregulation of NCX1 that has been demonstrated to be neuroprotective. Furthermore, RLIP restored MTF-1 and NCX1 protein levels in the ischemic rat brain cortex and the silencing of MTF-1 prevented the increase of NCX1 observed in RLIP protected rats, thus demonstrating a direct regulation of NCX1 by MTF-1 in the ischemic cortex of rat exposed to tMCAO followed by FAO. Moreover, silencing of MTF-1 significantly reduced the neuroprotective effect elicited by RLIP as demonstrated by the enlargement of brain infarct volume observed in rats subjected to RLIP and treated with MTF-1 silencing. Overall, MTF-dependent activation of NCX1 and their upregulation elicited by RLIP, besides unraveling a new molecular pathway of neuroprotection during brain ischemia, might represent an additional mechanism to intervene in stroke pathophysiology
The Transcriptional Complex Sp1/KMT2A by Up-Regulating Restrictive Element 1 Silencing Transcription Factor Accelerates Methylmercury-Induced Cell Death in Motor Neuron-Like NSC34 Cells Overexpressing SOD1-G93A
Methylmercury (MeHg) exposure has been related to amyotrophic lateral sclerosis (ALS) pathogenesis and molecular mechanisms of its neurotoxicity has been associated to an overexpression of the Restrictive Element 1 Silencing Transcription factor (REST). Herein, we evaluated the possibility that MeHg could accelerate neuronal death of the motor neuron-like NSC34 cells transiently overexpressing the human Cu2+/Zn2+superoxide dismutase 1 (SOD1) gene mutated at glycine 93 (SOD1-G93A). Indeed, SOD1-G93A cells exposed to 100 nM MeHg for 24 h showed a reduction in cell viability, as compared to cells transfected with empty vector or with unmutated SOD1 construct. Interestingly, cell survival reduction in SOD1-G93A cells was associated with an increase of REST mRNA and protein levels. Furthermore, MeHg increased the expression of the transcriptional factor Sp1 and promoted its binding to REST gene promoter sequence. Notably, Sp1 knockdown reverted MeHg-induced REST increase. Co-immunoprecipitation experiments demonstrated that Sp1 physically interacted with the epigenetic writer Lysine-Methyltransferase-2A (KMT2A). Moreover, knocking-down of KMT2A reduced MeHg-induced REST mRNA and protein increase in SOD1-G93A cells. Finally, we found that MeHg-induced REST up-regulation triggered necropoptotic cell death, monitored by RIPK1 increased protein expression. Interestingly, REST knockdown or treatment with the necroptosis inhibitor Necrostatin-1 (Nec) decelerated MeH-induced cell death in SOD1-G93A cells. Collectively, this study demonstrated that MeHg hastens necroptotic cell death in SOD1-G93A cells via Sp1/KMT2A complex, that by epigenetic mechanisms increases REST gene expression
Multiplicative noise: A mechanism leading to nonextensive statistical mechanics
A large variety of microscopic or mesoscopic models lead to generic results
that accommodate naturally within Boltzmann-Gibbs statistical mechanics (based
on ). Similarly, other classes of models
point toward nonextensive statistical mechanics (based on , where the value of the entropic index depends on
the specific model). We show here a family of models, with multiplicative
noise, which belongs to the nonextensive class. More specifically, we consider
Langevin equations of the type , where
and are independent zero-mean Gaussian white noises with
respective amplitudes and . This leads to the Fokker-Planck equation
. Whenever the
deterministic drift is proportional to the noise induced one, i.e., , the stationary solution is shown to be (with and ). This distribution is
precisely the one optimizing with the constraint constant. We also
introduce and discuss various characterizations of the width of the
distributions.Comment: 3 PS figure
Involvement of phosphodiesterase-cGMP-PKG pathway in intracellular Ca2+ oscillations in pituitary GH3 cells
AbstractThe present study investigates the potential role of the Ca2+-calmodulin-dependent type I phosphodiesterase (PDE)-cGMP-protein kinase G (PKG) pathway in spontaneous [Ca2+]i oscillations in GH3 cells using fura-2 single cell videoimaging. Vinpocetine (2.5–50 μM), a selective inhibitor of type I PDE, induced a concentration-dependent inhibition of spontaneous [Ca2+]i oscillations in these pituitary cells, and at the same time produced an increase of the intracellular cGMP content. The cell permeable cGMP analog N2,2′-O-dibutyryl-cGMP (dB-cGMP) (1 mM) caused a progressive reduction of the frequency and the amplitude of spontaneous [Ca2+]i oscillations when added to the medium. KT5823 (400 nM), a selective inhibitor of cGMP-dependent protein kinase (PKG), produced an increase of baseline [Ca2+]i and the disappearance of spontaneous [Ca2+]i oscillations. When KT5823 was added before vinpocetine, the PKG inhibitor counteracted the [Ca2+]i lowering effect of the cGMP catabolism inhibitor. Finally, the removal of extracellular Ca2+ or the blockade of L-type voltage-sensitive calcium channels (VSCC) by nimodipine produced a decrease of cytosolic cGMP levels. Collectively, the results of the present study suggest that spontaneous [Ca2+]i oscillations in GH3 cells may be regulated by the activity of type I PDE-cGMP-PKG pathway
Targeted acetylation of NF-kappaB/RelA and histones by epigenetic drugs reduces post-ischemic brain injury in mice with an extended therapeutic window.
Nuclear factor-kappaB (NF-κB) p50/RelA is a key molecule with a dual effect in the progression of ischemic stroke. In harmful ischemia, but not in preconditioning insult, neurotoxic activation of p50/RelA is characterized by RelA-specific acetylation at Lys310 (K310) and deacetylation at other Lys residues. The derangement of RelA acetylation is associated with activation of Bim promoter. Objective: With the aim of producing neuroprotection by correcting altered acetylation of RelA in brain ischemia, we combined the pharmacological inhibition of histone deacetylase (HDAC) 1-3, the enzymes known to reduce global RelA acetylation, and the activation of sirtuin 1, endowed with a specific deacetylase activity on the K310 residue of RelA. To afford this aim, we tested the clinically used HDAC 1-3 inhibitor entinostat (MS-275) and the sirtuin 1 activator resveratrol. Methods: We used the mouse model of transient middle cerebral artery occlusion (MCAO) and primary cortical neurons exposed to oxygen glucose deprivation (OGD). Results: The combined use of MS-275 and resveratrol, by restoring normal RelA acetylation, elicited a synergistic neuroprotection in neurons exposed to OGD. This effect correlated with MS-275 capability to increase total RelA acetylation and resveratrol capability to reduce RelA K310 acetylation through the activation of an AMP-activated protein kinase-sirtuin 1 pathway. The synergistic treatment reproduced the acetylation state of RelA peculiar of preconditioning ischemia. Neurons exposed to the combined drugs totally recovered the optimal histone H3 acetylation.Neuroprotection was reproduced in mice subjected to MCAO and treated with MS-275 (20μg/kg and 200μg/kg) or resveratrol (6800μg/kg) individually. However, the administration of lowest doses of MS-275 (2μg/kg) and resveratrol (68μg/kg) synergistically reduced infarct volume and neurological deficits. Importantly, the treatment was effective even when administered 7h after the stroke onset. Chromatin immunoprecipitation analysis of cortices harvested from treated mice showed that the RelA binding and histone acetylation increased at the Bcl-x L promoter and decreased at the Bim promoter. Conclusion: Our study reveals that epigenetic therapy shaping acetylation of both RelA and histones may be a promising strategy to limit post-ischemic injury with an extended therapeutic window
miR-16-5p, miR-103-3p, and miR-27b-3p as Early Peripheral Biomarkers of Fetal Growth Restriction
Current tests available to diagnose fetal hypoxia in-utero lack sensitivity thus failing to identify many fetuses at risk. Emerging evidence suggests that microRNAs derived from the placenta circulate in the maternal blood during pregnancy and may be used as non-invasive biomarkers for pregnancy complications. With the intent to identify putative markers of fetal growth restriction (FGR) and new therapeutic druggable targets, we examined, in maternal blood samples, the expression of a group of microRNAs, known to be regulated by hypoxia. The expression of microRNAs was evaluated in maternal plasma samples collected from (1) women carrying a preterm FGR fetus (FGR group) or (2) women with an appropriately grown fetus matched at the same gestational age (Control group). To discriminate between early- and late-onset FGR, the study population was divided into two subgroups according to the gestational age at delivery. Four microRNAs were identified as possible candidates for the diagnosis of FGR: miR-16-5p, miR-103-3p, miR-107-3p, and miR-27b-3p. All four selected miRNAs, measured by RT-PCR, resulted upregulated in FGR blood samples before the 32nd week of gestation. By contrast, miRNA103-3p and miRNA107-3p, analyzed between the 32nd and 37th week of gestation, showed lower expression in the FGR group compared to aged matched controls. Our results showed that measurement of miRNAs in maternal blood may form the basis for a future diagnostic test to determine the degree of fetal hypoxia in FGR, thus allowing the start of appropriate therapeutic interventions to alleviate the burden of this disease
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