TLR4 elimination prevents synaptic and myelin alterations and long-term cognitive dysfunctions in adolescent mice with intermittent ethanol treatment.

The adolescent brain undergoes important dynamic and plastic cell changes, including overproduction of axons and synapses, followed by rapid pruning along with ongoing axon myelination. These developmental changes make the adolescent brain particularly vulnerable to neurotoxic and behavioral effects of alcohol. Although the mechanisms of these effects are largely unknown, we demonstrated that ethanol by activating innate immune receptors toll-like receptor 4 (TLR4), induces neuroinflammation and brain damage in adult mice. The present study aims to evaluate whether intermittent ethanol treatment in adolescence promotes TLR4-dependent pro-inflammatory processes, leading to myelin and synaptic dysfunctions, and long-term cognitive impairments. Using wild-type (WT) and TLR4-deficient (TLR4-KO) adolescent mice treated intermittently with ethanol (3.0g/kg) for 2weeks, we show that binge-like ethanol treatment activates TLR4 signaling pathways (MAPK, NFκB) leading to the up-regulation of cytokines and pro-inflammatory mediators (COX-2, iNOS, HMGB1), impairing synaptic and myelin protein levels and causing ultrastructural alterations. These changes were associated with long-lasting cognitive dysfunctions in young adult mice, as demonstrated with the object recognition, passive avoidance and olfactory behavior tests. Notably, elimination of TLR4 receptors prevented neuroinflammation along with synaptic and myelin derangements, as well as long-term cognitive alterations. These results support the role of the neuroimmune response and TLR4 signaling in the neurotoxic and behavioral effects of ethanol in adolescence.

Neuroimmune activation and myelin changes in adolescent rats exposed to high-dose alcohol and associated cognitive dysfunction: a review with reference to human adolescent drinking.

AIMS: The aim of the study was to assess whether intermittent ethanol administration to adolescent rats activates innate immune response and TLRs signalling causing myelin disruption and long-term cognitive and behavioural deficits. METHODS: We used a rat model of intermittent binge-like ethanol exposure during adolescence. RESULTS: Binge-like ethanol administration to adolescent rats increased the gene expression of TLR4 and TLR2 in the prefrontal cortex (PFC), as well as inflammatory cytokines TNFα and IL-1ß. Up-regulation of TLRs and inflammatory mediators were linked with alterations in the levels of several myelin proteins in the PFC of adolescent rats. These events were associated with previously reported long-term cognitive dysfunctions. Conversely, the same ethanol treatment did not cause significant changes in either inflammatory mediators or myelin changes in the brain of adult rats. CONCLUSION: Activation of innate immune receptors TLRs in the PFC appears to be involved in the neuroinflammation and demyelination processes induced by ethanol exposure during adolescence. The findings support the vulnerability of the juvenile brain to the effects of ethanol and the long-term cognitive consequences of binge drinking. In addition, ethanol-induced PFC dysfunctions might underlie the propensity of adolescents for impulsivity and to ignore the negative consequences of their behaviour, both of which could increase the risk of substance abuse.

Prohibitin depletion extends lifespan of a TORC2/SGK-1 mutant through autophagy and the mitochondrial UPR.

Mitochondrial prohibitins (PHB) are highly conserved proteins with a peculiar effect on lifespan. While PHB depletion shortens lifespan of wild-type animals, it enhances longevity of a plethora of metabolically compromised mutants, including target of rapamycin complex 2 (TORC2) mutants sgk-1 and rict-1. Here, we show that sgk-1 mutants have impaired mitochondrial homeostasis, lipogenesis and yolk formation, plausibly due to alterations in membrane lipid and sterol homeostasis. Remarkably, all these features are suppressed by PHB depletion. Our analysis shows the requirement of SRBP1/SBP-1 for the lifespan extension of sgk-1 mutants and the further extension conferred by PHB depletion. Moreover, although the mitochondrial unfolded protein response (UPRmt ) and autophagy are induced in sgk-1 mutants and upon PHB depletion, they are dispensable for lifespan. However, the enhanced longevity caused by PHB depletion in sgk-1 mutants requires both, the UPRmt and autophagy, but not mitophagy. We hypothesize that UPRmt induction upon PHB depletion extends lifespan of sgk-1 mutants through autophagy and probably modulation of lipid metabolism.

Autophagy Constitutes a Protective Mechanism against Ethanol Toxicity in Mouse Astrocytes and Neurons.

Ethanol induces brain damage and neurodegeneration by triggering inflammatory processes in glial cells through activation of Toll-like receptor 4 (TLR4) signaling. Recent evidence indicates the role of protein degradation pathways in neurodegeneration and alcoholic liver disease, but how these processes affect the brain remains elusive. We have demonstrated that chronic ethanol consumption impairs proteolytic pathways in mouse brain, and the immune response mediated by TLR4 receptors participates in these dysfunctions. We evaluate the in vitro effects of an acute ethanol dose on the autophagy-lysosome pathway (ALP) on WT and TLR4-/- mouse astrocytes and neurons in primary culture, and how these changes affect cell survival. Our results show that ethanol induces overexpression of several autophagy markers (ATG12, LC3-II, CTSB), and increases the number of lysosomes in WT astrocytes, effects accompanied by a basification of lysosomal pH and by lowered phosphorylation levels of autophagy inhibitor mTOR, along with activation of complexes beclin-1 and ULK1. Notably, we found only minor changes between control and ethanol-treated TLR4-/- mouse astroglial cells. Ethanol also triggers the expression of the inflammatory mediators iNOS and COX-2, but induces astroglial death only slightly. Blocking autophagy by using specific inhibitors increases both inflammation and cell death. Conversely, in neurons, ethanol down-regulates the autophagy pathway and triggers cell death, which is partially recovered by using autophagy enhancers. These results support the protective role of the ALP against ethanol-induced astroglial cell damage in a TLR4-dependent manner, and provide new insight into the mechanisms that underlie ethanol-induced brain damage and are neuronal sensitive to the ethanol effects.

Transcriptional repression of the tumor suppressor DRO1 by AIB1.

Using transcriptomic gene expression profiling we found tumor suppressor DRO1 being repressed in AIB1 transgenic mice. In agreement, AIB1 represses DRO1 promoter and its expression levels inversely correlate with DRO1 in several cancer cell lines and in ectopic and silencing assays. Estrogen modulators treatment showed a regulation in an estrogen receptor-dependent fashion. Importantly, DRO1 overexpression resulted in BCLAF1 upregulation, a compelling concept given that BCLAF1 is a death-promoting transcriptional repressor. Additionally, DRO1 shuttles from Golgi to the endoplasmic reticulum upon apoptotic stimuli, where it is predicted to facilitate the apoptosis cascade. Finally, DRO1 repression is an important factor for AIB1-mediated inhibition of apoptosis. Collectively, our results reveal DRO1 as an AIB1-targeted tumor suppressor, providing a novel mechanism for AIB1-dependent inhibition of apoptosis.

[Test to measure basic life support and defibrillation skills in primary care doctors and nurses]. / Test Raval Sud para medir habilidades de soporte vital básico y desfibrilación en médicos y enfermeras de atención primaria.

OBJECTIVE: To prepare and validate a tool to measure Basic Life Support (BLS) and semi-automatic defibrillator (SAD) skills adapted for use by health professionals in Primary Care Teams (PCT). To propose an updated version and demonstrate self-sufficiency of the team to use it in a training evaluation. DESIGN: Validation of measurement tools. Study of reliability with repeated measurements after a training course. SETTING: Drassanes Primary Care Centre. Raval Sud Basic Health Area. Barcelona. Spain. PARTICIPANTS: A total of 37 voluntary resuscitators (all doctors/nurses), professional camera, medical controller, computerised mannequin, 6 evaluators. INTERVENTIONS: Test preparation methodology. Cardiff Model 3.1. IMPLEMENTATION: 2 filmed series (professional+domestic), of 26-25 "station type" simulations, separated by 1 month. A training workshop between series. Retrospective evaluation of DVD recordings (5 evaluators). 2nd series scored again at 3 weeks with a blind and random order filmed version. VARIABLES: performances classified from worse to best execution. Psychometric analysis: Validity (content/apparent). Test-retest reliability, between-observer and sensitivity to change. RESULTS: Compared to the Cardiff test (46 items) our 83 item test contained 38(46%) new, 34(41%) modified and 11(13%) similar. Between-evaluator reliability, excellent/good in 51/62 items analysed; Within-evaluator and between-filming reliability, excellent/good in all except 1 item; the test score doubled after the training course. A version of the test according to BLS-SAD recommendations is proposed. CONCLUSIONS: On there not being useful tools available for Primary Care doctors and nurses, one has been prepared with adequate psychometric guarantees and proven self-sufficient evaluation. We propose the immediate application of the updated version for training evaluation purposes.