Ethanol influences on Bax translocation, mitochondrial membrane potential, and reactive oxygen species generation are modulated by vitamin E and brain-derived neurotrophic factor

Artabotrys odoratissimus Bark Extract Restores Ethanol Induced Redox Imbalance and Toxicity in Hepatocytes and In Vivo Model

Alcohol-induced oxidative stress is a key player in the development of liver diseases, and herbal alternatives are important means of ameliorating the hepatotoxic effects. The study aimed to evaluate the hepatoprotective potentiality of Artabotrys odoratissimus, an important medicinal shrub from the family Annonaceae. The phenolic compounds from bark ethanol extract (BEE) were detected using RP-HPLC. The in vitro hepatoprotective activity against ethanol-induced damage was studied in HepG2 cells with cell viability assays, mitochondrial membrane potential (MMP) assay, reactive oxygen species (ROS) assay, double staining assay and western blotting. The in vivo mice model was used to evaluate the alcohol-induced stress with liver function enzymes, lipid profile and histopathology. All the thirteen phenolic compounds detected with HPLC were docked onto protein targets such as aspartate amino transferase (AST), alkaline phosphatase (ALP) and inducible nitric oxide synthase (NO). The RP-HPLC detected the presence of various phenolics including rutin, chlorogenic acid and catechin, amongst others. Co-administration of BEE with ethanol alleviated cell death, ROS and MMP in HepG2 cells compared to the negative control. The extract also modulated the MAP kinase/caspase-3 pathway, thereby showing protective effects in HepG2 cells. Also, pre-treatment for 14 days with the extract in the mice model before a single toxic dose (5 g/kg body weight) reduced the liver injury by bringing the levels of liver function enzymes, lipid profile and bilirubin to near normal. In silico analysis revealed that rutin showed the best binding affinity with all the target proteins in the study. These results provide evidence that BEE possesses significant hepatoprotective effects against ethanol-induced oxidative stress in hepatic cells and in vivo models, which is further validated with in silico analysis.

Assessment of Ethanol Exposure from Hand Sanitizer Use and Potential for Developmental Toxicity in Nursing Infants

Ingestion of ethanol during pregnancy is known to have detrimental effects on the fetus. Although the potential developmental effects of maternal ethanol intake during lactation are less well characterized, public health guidelines recommend avoidance of alcohol or, if alcohol is consumed, to allow for 1–2 h to pass before nursing. A proposal to classify ethanol as potentially harmful to breast‐fed children warrants an investigation of the potential adverse neurodevelopmental effects of low‐dose ethanol exposure during lactation. There currently are no studies that have examined neurodevelopmental outcomes from lactational exposure to ethanol from the use of topical products that contain ethanol, such as alcohol‐based hand sanitizers (ABHS). Furthermore, the epidemiological literature of lactational ethanol exposures from maternal alcohol consumption is limited in design, provides equivocal evidence of neurological effects in infants, and is insufficient to characterize a dose–response relationship for developmental effects. Toxicological studies that observed neurodevelopmental effects in pups from ethanol via lactation did so at exceedingly high doses that also caused maternal toxicity. In this investigation, blood ethanol concentrations (BECs) of breastfeeding women following typical‐to‐intense ABHS use were computationally predicted and compared to health benchmarks to quantify the risk for developmental outcomes. Margins of 2.2 to 1000 exist between BECs associated with ABHS use compared to BECs associated with neurotoxicity adverse effect levels in the toxicology literature or oral ethanol intake per public health guidelines. Neurodevelopmental effects are not likely to occur in infants due to ABHS use by breastfeeding women, even when ABHSs are used at intense frequencies.

Adverse neurodevelopmental effects of ethanol exposure are supported by toxicological studies; ethanol as a potential “lactation hazard” needs evaluation. A lactation hazard may not be applicable for all ethanol‐containing products, such as hand sanitizers. Furthermore, internal dose assessments of hand sanitizer use are lacking. Computationally modeled blood ethanol concentrations following hand sanitizer use are lower than concentrations associated with toxicological and guideline benchmarks. Therefore, there is low potential for the use of ethanol‐containing hand sanitizers to be a lactation hazard.

Pilot Study on Analysis of Electroencephalography Signals from Children with FASD with the Implementation of Naive Bayesian Classifiers

In this paper Naive Bayesian classifiers were applied for the purpose of differentiation between the EEG signals recorded from children with Fetal Alcohol Syndrome Disorders (FASD) and healthy ones. This work also provides a brief introduction to the FASD itself, explaining the social, economic and genetic reasons for the FASD occurrence. The obtained results were good and promising and indicate that EEG recordings can be a helpful tool for potential diagnostics of FASDs children affected with it, in particular those with invisible physical signs of these spectrum disorders.

Caffeine Potentiates Ethanol-Induced Neurotoxicity Through mTOR/p70S6K/4E-BP1 Inhibition in SH-SY5Y Cells

Caffeine is a popular psychostimulant, which is frequently consumed with ethanol. However, the effects of caffeine on neuronal cells constantly exposed to ethanol have not been investigated. Apoptosis and oxidative stress occurring in ethanol-induced neurotoxicity were previously associated with decreased phosphorylation of the mTOR/p70S6K/4E-BP1 signaling proteins. Evidence also suggested that caffeine inhibits the mTOR pathway. In this study, human SH-SY5Y neuroblastoma cells were exposed to caffeine after pretreatment for 24 hours with ethanol. Results indicated that both ethanol and caffeine caused neuronal cell death in a dose- and time-dependent manner. Exposure to 20-mM caffeine for 24 hours magnified reduced cell viability and enhanced apoptotic cell death induced by 200 mM of ethanol pretreatment. The phosphorylation of mTOR, p70S6K, and 4E-BP1 markedly decreased in cells exposed to caffeine after ethanol pretreatment, associated with a decrease of the mitochondrial membrane potential (ΔΨm). These findings suggested that caffeine treatment after neuronal cells were exposed to ethanol resulted in marked cell damages, mediated through enhanced inhibition of mTOR/p70S6K/4E-BP1 signaling leading to impaired ΔΨm and, eventually, apoptotic cell death.

Inhibition of the electron transport chain in propofol induced neurotoxicity in zebrafish embryos

Fetal and neonatal exposure to propofol can lead to neuronal death and long-term neurobehavioral deficiencies in both rodents and nonhuman primates. Zebrafish embryo, which is fertilized ex-utero, has provided us a new model species to study the effects of general anesthetics on developing brain. Inhibited electron transport chain leads to mitochondrial dysfunction and insufficient energy production. The aim of this study was to dissect the role of electron transport chain in propofol-induced neurotoxicity. 6 h post fertilization (hpf) zebrafish embryos were exposed to control or 1, 2 or 4 μg/ml propofol until 48hpf. Acridine orange staining was used to assess cell apoptosis in the brain of zebrafish embryos. The activity of mitochondrial electron transport chain complex was assessed using colorimetric method. Expression of key subunit of cytochrome c oxidase was assessed by western blot and transcription level of cox4i1 was assessed by quantitative real time-PCR. The mitochondrial membrane potential and ATP content were assessed. Exposure to 1, 2 and 4 μg/ml propofol induced significant increases in cell apoptosis in the brain of zebrafish embryos in a dose-dependent manner and led to significant decreases in electron transport chain complex IV activity from (0.161 ± 0.023)μmol/mg/min in blank control-treated group to (0.096 ± 0.015)μmol/mg/min, (0.083 ± 0.013)μmol/mg/min and (0.045 ± 0.014)μmol/mg/min respectively, accompanied by decreased expression of key regulatory subunit of cytochrome c oxidase-subunit IV and decreased transcription level of cox4i1. Propofol exposure also decreased the mitochondrial membrane potential and ATP content. Our findings demonstrate that inhibition of the electron transport chain is involved in the mechanisms by which propofol induces neurotoxicity in the developing brain.

Propolis ameliorates cerebral injury in focal cerebral ischemia/reperfusion (I/R) rat model via upregulation of TGF-β1

Neuroprotective impact of transforming growth factor β1 (TGF-β1) is increasingly recognized in different brain injuries. Propolis exhibits a broad spectrum of biological and pharmacological properties including neuroprotective action. The objective of the investigation was to explore the involvement of TGF-β1 signaling in the neuroprotective mechanism of propolis in I/R rats. In this study, focal cerebral ischemia model was built by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion. The investigation was carried out on 48 rats that were arranged into four groups (n = 12): the sham group, I/R control group, I/R + propolis (50 mg/kg) group and I/R + propolis (100 mg/kg) group. The results revealed that propolis preserved rats against neuronal injury induced by cerebral I/R. It significantly reduced neurological deficit scores and improved motor coordination and locomotor activity in I/R rats. Propolis antagonized the damage induced by cerebral I/R through suppression of malondialdehyde (MDA) and elevation of reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), brain-derived neurotropic factor (BDNF) and dopamine levels in the brain homogenates of I/R rats. Other ameliorations were also observed based on reduction of neurodegeneration and histological alterations in the brain tissues. These results also proposed that the neuroprotective effect of propolis might be related to upregulation of TGF-β1 and suppressed matrix metallopeptidase-9 (MMP9) mRNA expression.

Diterpene pekinenal from euphorbia pekinensis radix induced IEC-6 cells apoptosis mediated by mitochondria and death receptors

Pekinenal, a diterpenoid from the roots of Euphorbia pekinensis Rupr., can cause serious intestinal toxicity. However, its toxic mechanism hasn't been comprehensively understood. This present study aims to clarify its toxic effects and investigate the potential mechanism. In vitro effects of pekinenal on cell proliferation, cell cycle and apoptosis were examined by performing experiments on rat intestinal crypt epithelial cells (IEC-6). Proteins and enzymes involved in cell apoptotic pathways were detected by Western blot and enzyme-linked immunosorbent assay (ELISA), and related mRNAs were detected by RT-PCR. The results showed that the cell cycle was arrested in G0/G1 phase, and apoptotic morphology changes in pekinenal-treated cells. Furthermore, pekinenal up-regulated the expression level of apoptotic protein including Bax, AIF, Apaf-1 and the expression level of mRNA such as Fas, FasL, TNFR1 and NF-κB, while down-regulated the expression level of Bcl-2, ultimately triggering the apoptosis of caspase dependence. In conclusion, the above data confirmed that pekinenal inhibited the proliferation of IEC-6 cells and induced cells apoptosis by modulating mitochondrial and death receptor pathways.

Retinal Wnt signaling defect in a zebrafish fetal alcohol spectrum disorder model

Fetal alcohol spectrum disorder caused by prenatal alcohol exposure includes ocular abnormalities (microphthalmia, photoreceptor dysfunction, cataracts). Zebrafish embryos exposed to ethanol from gastrulation through somitogenesis show severe ocular defects, including microphthalmia and photoreceptor differentiation defects. Ethanol-treated zebrafish had an enlarged ciliary marginal zone (CMZ) relative to the retina size and reduced Müller glial cells (MGCs). Ethanol exposure produced immature photoreceptors with increased proliferation, indicating cell cycle exit failure. Signaling mechanisms in the CMZ were affected by embryonic ethanol exposure, including Wnt signaling in the CMZ, Notch signaling and neurod gene expression. Retinoic acid or folic acid co-supplementation with ethanol rescued Wnt signaling and retinal differentiation. Activating Wnt signaling using GSK3 inhibitor (LSN 2105786; Eli Lilly and Co.) restored retinal cell differentiation pathways. Ethanol exposed embryos were treated with Wnt agonist, which rescued Wnt-active cells in the CMZ, Notch-active cells in the retina, proliferation, and photoreceptor terminal differentiation. Our results illustrate the critical role of Wnt signaling in ethanol-induced retinal defects.

Betulinic acid induces apoptosis and inhibits metastasis of human renal carcinoma cells in vitro and in vivo

Betulinic acid (BA), a natural product with a broad range of biological properties, is a lupane-type pentacyclic triterpene isolated from various plants. Evidence is accumulating that BA is cytotoxic against multiple types of human cancer cells; however, its effects on renal carcinoma cells remain obscure. This study aimed to evaluate the anticancer activity of BA in human renal cancer cells in vitro and in vivo. In the current study, we found that BA inhibited renal cancer cell proliferation in a time-dependent and dose-dependent manner in vitro. Moreover, flow cytometry analysis revealed that BA affected the survival of renal cancer cells via the induction of apoptosis. Western blot analysis showed that the occurrence of apoptosis was associated with upregulation of Bcl2-associated X protein and cleaved caspase-3 and downregulation of B-cell lymphoma 2 in renal cancer cells. Additionally, BA treatment augmented the production of reactive oxygen species and induced a significant loss of mitochondrial membrane potential in renal cancer cells, suggesting that BA may trigger apoptosis via the mitochondria-mediated apoptotic pathway. Furthermore, the migrative and invasive capabilities of renal cancer cells were markedly repressed by BA treatment, which was related to upregulation of matrix metalloproteinase (MMP)2, MMP9, and vimentin, and downregulation of tissue inhibitor of metalloproteinase 2 and E-cadherin. Notably, administration of BA retarded tumor growth in 786-O-bearing mice in vivo. Taken together, our results demonstrated the anticancer potential of BA in human renal cancer cells by triggering apoptosis and suppressing migration and invasion.

ProBDNF/p75NTR/sortilin pathway is activated in peripheral blood of patients with alcohol dependence

Alcohol dependence is a worldwide problem with a great social and economic burden in many countries. A number of studies have suggested that BDNF (mature BDNF) and its precursor (proBDNF) play important roles in the alcohol dependence. However, what roles of the mBDNF/proBDNF pathways play during the pathological process of alcohol dependence are not clearly understood. In our clinical study, peripheral blood was sampled from 30 male patients with alcohol dependence and 50 healthy males (as control). The protein levels of proBDNF, p75NTR, sortilin, mBDNF, TrkB and mRNA levels of BDNF, p75NTR, sortilin, and TrkB were detected in the peripheral blood in our study. We found that the protein levels of proBDNF and p75NTR were increased, but not the sortilin protein level; while the TrkB protein level was decreased in the alcohol dependence patients compared with healthy controls. Moreover, the mRNA levels of p75NTR and sortilin from the lymphocytes were slightly increased; while BDNF and TrkB were significantly decreased. The ELISA results of mBDNF and TrkB were declined in the alcohol dependence group. The levels of mBDNF and TrkB were negatively correlated with the average amount of daily ethanol consumption, and the levels of proBDNF, p75NTR and sortilin were positively correlated with the average amount of ethanol consumption per day. The ratio of proBDNF to mBDNF was altered in alcohol dependence patients. The balance between the proBDNF/p75NTR and mBDNF/TrkB signalling pathways appeared dysregulated in alcohol dependence. Our results suggested that both pathways may participate in the complex processes of alcohol dependence.

Effect of Thymoquinone on Reproductive Parameter in Morphine-treated Male Mice

BACKGROUND

Thymoquinone as the main active component of Nigella sativa might have a various pharmacological effects such as antiapoptotic and antioxidant. Morphine is commonly used for the treatment of severe pain that can increase the generation of free radicals and affects the spermatogenesis. This study was designed to evaluate protective effects of thymoquinone against morphine-induced damages, sperm viability, count, motility, morphology and testis histology, and nitric oxide and testosterone hormone of the mice.

MATERIALS AND METHODS

In this experimental study, we divided 48 mice into eight groups (n = 6); various doses of thymoquinone (2, 10, and 20 mg/kg) and morphine (20 mg/kg) plus thymoquinone (2, 10, and 20 mg/kg) were administered intraperitoneally to 48 male mice for 30 consequent days. Male reproductive parameters including testis weight, testosterone hormone, serum nitric oxide, germinal thickness, sperm morphology, count, viability, and motility were analyzed and compared.

RESULTS

The results indicated that morphine administration significantly decreased germinal thickness, testis weight, testosterone level, viability, morphology, count, and motility of sperm and increased nitric oxide as compared to saline group (P < 0.05). However, increasing the dose of thymoquinone in the thymoquinone and thymoquinone plus morphine groups significantly decreases nitric oxide level (P < 0.05) while significantly boosted motility, morphology, count, viability of sperm cells, germinal thickness, and testosterone hormone in all groups as compared to morphine group (P < 0.05).

CONCLUSION

It seems that thymoquinone administration could increase the quality some of spermatozoa and improves morphine-induced adverse effects on reproductive parameters in male mice.

The Effects of Thymoquinone Against Morphine-induced Damages on Male Mice Liver

BACKGROUND

Morphine is a pain medication. It is mostly processed in liver and reasons disturbing effects. It can increase the production of free radicals. Thymoquinone is a phytochemical compound found in the plant Nigella sativa. It has diverse pharmacological properties such as antioxidant and anticancer. This study was intended to assess the effects of thymoquinone against morphine damages on the liver of mice.

METHODS

In this study, various doses of thymoquinone (4.5, 9, and 18 mg/kg) and thymoquinone plus morphine was administered (once a day) intraperitoneally to 48 male mice for 20 consequent days. These mice were randomly assigned to eight groups (n = 6). Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, serum nitric oxide (NO) levels, liver weight, and histology have been studied.

RESULTS

The results indicated that morphine administration significantly increased the mean diameter of central hepatic vein and hepatocyte, blood serum NO level, liver enzymes level, and decreased liver weight compared to saline group (P < 0.05). However, thymoquinone and thymoquinone plus morphine administration significantly enhanced liver weight and reduced the mean diameter of hepatocyte, central hepatic vein, liver enzymes, and NO levels in all groups compared to morphine group (P < 0.05).

CONCLUSIONS

It seems that antioxidant effect of thymoquinone could protect damage of liver parameters against morphine toxicity.

Turmeric Extract Rescues Ethanol-Induced Developmental Defect in the Zebrafish Model for Fetal Alcohol Spectrum Disorder (FASD)

Prenatal ethanol exposure causes the most frequent preventable birth disorder, fetal alcohol spectrum disorder (FASD). The effect of turmeric extracts in rescuing an ethanol-induced developmental defect using zebrafish as a model was determined. Ethanol-induced oxidative stress is one of the major mechanisms underlying FASD. We hypothesize that antioxidant inducing properties of turmeric may alleviate ethanol-induced defects. Curcuminoid content of the turmeric powder extract (5 mg/mL turmeric in ethanol) was determined by UPLC and found to contain Curcumin (124.1 ± 0.2 μg/mL), Desmethoxycurcumin (43.4 ± 0.1 μg/mL), and Bisdemethoxycurcumin (36.6 ± 0.1 μg/mL). Zebrafish embryos were treated with 100 mM (0.6% v/v) ethanol during gastrulation through organogenesis (2 to 48 h postfertilization (hpf)) and supplemented with turmeric extract to obtain total curcuminoid concentrations of 0, 1.16, 1.72, or 2.32 μM. Turmeric supplementation showed significant rescue of the body length at 72 hpf compared to ethanol-treated embryos. The mechanism underlying the rescue remains to be determined.

The Neuroprotective Effects of Carvacrol on Ethanol-Induced Hippocampal Neurons Impairment via the Antioxidative and Antiapoptotic Pathways

Chronic alcohol consumption causes hippocampal neuronal impairment, which is associated with oxidative stress and apoptosis. Carvacrol is a major monoterpenic phenol found in essential oils from the family Labiatae and has antioxidative stress and antiapoptosis actions. However, the protective effects of carvacrol in ethanol-induced hippocampal neuronal impairment have not been fully understood. We explored the neuroprotective effects of carvacrol in vivo and in vitro. Male C57BL/6 mice were exposed to 35% ethanol for 4 weeks to establish ethanol model in vivo, and hippocampal neuron injury was simulated by 200 mM ethanol in vitro. Morris water maze test was performed to evaluate the cognitive dysfunction. The oxidative stress injury of hippocampal neurons was evaluated by measuring the levels of oxidative stress biomarkers. Histopathological examinations and western blot were performed to evaluate the apoptosis of neurons. The results showed that carvacrol attenuates the cognitive dysfunction, oxidative stress, and apoptosis of the mice treated with ethanol and decreases hippocampal neurons apoptosis induced by ethanol in vitro. In addition, western blot analysis revealed that carvacrol modulates the protein expression of Bcl-2, Bax, caspase-3, and p-ERK, without influence of p-JNK and p-p38. Our results suggest that carvacrol alleviates ethanol-mediated hippocampal neuronal impairment by antioxidative and antiapoptotic effects.

Apoptotic cell death and temporal expression of apoptotic proteins Bcl-2 and Bax in the hippocampus, following binge ethanol in the neonatal rat model

BACKGROUND

Binge-like ethanol (EtOH) exposure during the early rat neonatal period results in acute cell loss in specific brain regions, but such acute cell death has not been well established in the hippocampus. Binge alcohol exposure can also result in protein expression changes in the cerebellum that could alter cell fate, but this has not been reported for the hippocampal subregions. This study investigates acute apoptotic cell death in hippocampal regions CA1, CA3, and dentate gyrus (DG) following a binge EtOH exposure on postnatal day (PN) 6, PN8, or PN6 + 8 and the alteration in pro- and anti-apoptotic proteins following a single EtOH binge on PN6.

METHODS

Apoptotic cell death was quantified 12 hours after EtOH binge exposure using the optical fractionator method. Western blot analysis determined expression of pro-apoptotic Bax and anti-apoptotic Bcl-2, 12, 24, and 48 hours after binge EtOH exposure on PN6. The Bcl-2:Bax ratio was used as a measure of vulnerability to apoptosis.

RESULTS

Acute apoptosis increased significantly 12 hours following PN6 or 8 EtOH exposure in CA1, CA3, and DG, but the magnitude of apoptotic cell death was significantly greater in CA1 than in CA3 and DG, which did not differ. Significant cell death was not detected when a PN8 EtOH exposure was preceded by exposure on PN6. Binge EtOH exposure on PN6 resulted in a significant increase in expression of Bcl-2 and the Bcl-2:Bax ratio in the CA1/DG region at 24 hours after EtOH exposure on PN6. The Bcl-2:Bax ratio in the CA3 region was not altered.

CONCLUSIONS

This study shows that repeated binge exposure does not have a cumulative effect on the magnitude of acute apoptotic cell death. This finding may be explained in part by changes in the Bcl-2:Bax ratio after a single binge EtOH exposure.

Differential effects of ethanol on bid, tBid, and Bax:tBid interactions in postnatal day 4 and postnatal day 7 rat cerebellum

BACKGROUND

Exposure to ethanol (EtOH) during central nervous system (CNS) development can lead to a wide array of neuroanatomical, behavioral, and cognitive abnormalities, broadly subsumed under the fetal alcohol spectrum disorder classification. One mode of EtOH-induced interference in the normal developmental program appears to be through induction of apoptotic processes mediated by the Bcl-2 family of survival-regulatory proteins. The present series of studies investigated the role of the Bcl-2-related, pro-apoptotic Bid protein, and its truncated, apoptotically active fragment, tBid, in developmental EtOH neurotoxicity.

METHODS

Protein analyses were made via enzyme-linked immunosorbent assays (ELISA) in neonatal rat cerebellum, of basal Bid, and of Bid and tBid, following EtOH exposure via vapor inhalation, at an age of peak EtOH sensitivity in this region (postnatal day 4 [P4]) and a later age of relative resistance (P7). ELISA analyses were also made of Bax:tBid heterodimers, a process which activates Bax, essential for its apoptotic functioning. Finally, in vitro assessments of the importance of tBid to EtOH neurotoxicity were made in cultured cerebellar granule cells, using a specific tBid inhibitor.

RESULTS

Basal levels of Bid were higher at P4 compared to P7, possibly contributing to the differential sensitivity. EtOH exposure elicited further increases in cytosolic Bid and mitochondrial tBid when administration was at P4, but not at P7. Bax:tBid heterodimers were markedly increased by EtOH exposure on P4, an increase which persisted even 2 hours after termination of treatment. Similar effects were not seen at P7. The in vitro analyses revealed that tBid inhibition provided complete protection against EtOH-induced cell death and depressed EtOH-mediated cytochrome-c release.

CONCLUSIONS

These results suggest that Bid/tBid may be important elements in EtOH-mediated neurotoxicity during CNS development. The molecular processes and interactions revealed may represent critical points which can be targeted in studies concerned with designing possible therapeutic strategies for minimizing these devastative effects.

Autophagy and ethanol neurotoxicity

Excessive ethanol exposure is detrimental to the brain. The developing brain is particularly vulnerable to ethanol such that prenatal ethanol exposure causes fetal alcohol spectrum disorders (FASD). Neuronal loss in the brain is the most devastating consequence and is associated with mental retardation and other behavioral deficits observed in FASD. Since alcohol consumption during pregnancy has not declined, it is imperative to elucidate the underlying mechanisms and develop effective therapeutic strategies. One cellular mechanism that acts as a protective response for the central nervous system (CNS) is autophagy. Autophagy regulates lysosomal turnover of organelles and proteins within cells, and is involved in cell differentiation, survival, metabolism, and immunity. We have recently shown that ethanol activates autophagy in the developing brain. The autophagic preconditioning alleviates ethanol-induced neuron apoptosis, whereas inhibition of autophagy potentiates ethanol-stimulated reactive oxygen species (ROS) and exacerbates ethanol-induced neuroapoptosis. The expression of genes encoding proteins required for autophagy in the CNS is developmentally regulated; their levels are much lower during an ethanol-sensitive period than during an ethanol-resistant period. Ethanol may stimulate autophagy through multiple mechanisms; these include induction of oxidative stress and endoplasmic reticulum stress, modulation of MTOR and AMPK signaling, alterations in BCL2 family proteins, and disruption of intracellular calcium (Ca2+) homeostasis. This review discusses the most recent evidence regarding the involvement of autophagy in ethanol-mediated neurotoxicity as well as the potential therapeutic approach of targeting autophagic pathways.

Zebrafish retinal defects induced by ethanol exposure are rescued by retinoic acid and folic acid supplement

Fetal Alcohol Spectrum Disorder (FASD) is caused by prenatal alcohol exposure, producing craniofacial, sensory, motor, and cognitive defects. FASD is highly prevalent in low socioeconomic populations, which are frequently accompanied by malnutrition. FASD-associated ocular pathologies include microphthalmia, optic nerve hypoplasia, and cataracts. The present study characterizes specific retinal tissue defects, identifies ethanol-sensitive stages during retinal development, and dissects the effect of nutrient supplements, such as retinoic acid (RA) and folic acid (FA) on ethanol-induced retinal defects. Exposure to pathophysiological concentrations of ethanol (during midblastula transition through somitogenesis; 2-24 h post fertilization [hpf]) altered critical transcription factor expression involved in retinal cell differentiation, and produced severe retinal ganglion cell, photoreceptor, and Müller glial differentiation defects. Ethanol exposure did not alter retinal cell differentiation induction, but increased retinal cell death and proliferation. RA and FA nutrient co-supplementation rescued retinal photoreceptor and ganglion cell differentiation defects. Ethanol exposure during retinal morphogenesis stages (16-24 hpf) produced retinal defects like those seen with ethanol exposure between 2 and 24 hpf. Significantly, during an ethanol-sensitive time window (16-24 hpf), RA co-supplementation moderately rescued these defects, whereas FA co-supplementation showed significant rescue of optic nerve and photoreceptor differentiation defects. Interestingly, RA, but not FA, supplementation after ethanol exposure could reverse ethanol-induced optic nerve and photoreceptor differentiation defects. Our results indicate that various ethanol-sensitive events underlie FASD-associated retinal defects. Nutrient supplements like retinoids and folate were effective in alleviating ethanol-induced retinal defects.

The effects of bioactive compounds from plant foods on mitochondrial function: a focus on apoptotic mechanisms

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

PDLLA/PRGD/β-TCP conduits build the neurotrophin-rich microenvironment suppressing the oxidative stress and promoting the sciatic nerve regeneration

A novel nerve guidance conduit comprising poly{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]} (PRGD), poly (d,l-lactic acid) (PDLLA) and β-tricalcium phosphate (β-TCP) was constructed to facilitate the peripheral nerve regeneration. From the comparative study, PDLLA/PRGD/β-TCP conduit achieved the best recovery in regard of the ultrastructure observation and the SFI evaluation. At the first stage of the injury (7 days), the maximum expression augments in ZnSOD (6.4 folds) and GPX4 (6.8 folds) were observed in PDLLA/PRGD/β-TCP group; while striking rise in actin (6.8 folds), tubulin (5.6 folds), and ERM components expressions were observed later (35 days). Meanwhile, compared with PDLLA and PDLLA/PRGD conduits, PDLLA/PRGD/β-TCP conduits achieved the highest local nerve growth factor (NGF) content and an accumulating BDNF content. We speculated that addition of RGD and β-TCP in the composites were the main positive factors to build the microenvironment rich in NGF and BDNF, which help to counteract with the oxidative stress and to boost the cytoskeletal protein expressions. Therefore, PDLLA/PRGD/β-TCP could be promising composites used in peripheral nerve regeneration.

Fetal Alcohol Spectrum Disorder (FASD) Associated Neural Defects: Complex Mechanisms and Potential Therapeutic Targets

Fetal alcohol spectrum disorder (FASD), caused by prenatal alcohol exposure, can result in craniofacial dysmorphism, cognitive impairment, sensory and motor disabilities among other defects. FASD incidences are as high as 2% to 5 % children born in the US, and prevalence is higher in low socioeconomic populations. Despite various mechanisms being proposed to explain the etiology of FASD, the molecular targets of ethanol toxicity during development are unknown. Proposed mechanisms include cell death, cell signaling defects and gene expression changes. More recently, the involvement of several other molecular pathways was explored, including non-coding RNA, epigenetic changes and specific vitamin deficiencies. These various pathways may interact, producing a wide spectrum of consequences. Detailed understanding of these various pathways and their interactions will facilitate the therapeutic target identification, leading to new clinical intervention, which may reduce the incidence and severity of these highly prevalent preventable birth defects. This review discusses manifestations of alcohol exposure on the developing central nervous system, including the neural crest cells and sensory neural placodes, focusing on molecular neurodevelopmental pathways as possible therapeutic targets for prevention or protection.

Involvement of sphingolipids in ethanol neurotoxicity in the developing brain

Ethanol-induced neuronal death during a sensitive period of brain development is considered one of the significant causes of fetal alcohol spectrum disorders (FASD). In rodent models, ethanol triggers robust apoptotic neurodegeneration during a period of active synaptogenesis that occurs around the first two postnatal weeks, equivalent to the third trimester in human fetuses. The ethanol-induced apoptosis is mitochondria-dependent, involving Bax and caspase-3 activation. Such apoptotic pathways are often mediated by sphingolipids, a class of bioactive lipids ubiquitously present in eukaryotic cellular membranes. While the central role of lipids in ethanol liver toxicity is well recognized, the involvement of sphingolipids in ethanol neurotoxicity is less explored despite mounting evidence of their importance in neuronal apoptosis. Nevertheless, recent studies indicate that ethanol-induced neuronal apoptosis in animal models of FASD is mediated or regulated by cellular sphingolipids, including via the pro-apoptotic action of ceramide and through the neuroprotective action of GM1 ganglioside. Such sphingolipid involvement in ethanol neurotoxicity in the developing brain may provide unique targets for therapeutic applications against FASD. Here we summarize findings describing the involvement of sphingolipids in ethanol-induced apoptosis and discuss the possibility that the combined action of various sphingolipids in mitochondria may control neuronal cell fate.

Ethanol influences on Bax associations with mitochondrial membrane proteins in neonatal rat cerebellum

These studies investigated interactions taking place at the mitochondrial membrane in neonatal rat cerebellum following ethanol exposure and focused on interactions between proapoptotic Bax and proteins of the permeability transition pore (PTP), voltage-dependent anion channel (VDAC) and adenine nucleotide translocator (ANT) of the outer and inner mitochondrial membranes, respectively. Cultured cerebellar granule cells were used to assess the role of these interactions in ethanol neurotoxicity. Analyses were made at the age of maximal cerebellar ethanol vulnerability (P4), compared to the later age of relative resistance (P7), to determine whether differential ethanol sensitivity was mirrored by differences in these molecular interactions. We found that, following ethanol exposure, Bax proapoptotic associations with both VDAC and ANT were increased, particularly at the age of greater ethanol sensitivity, and these interactions were sustained at this age for at least 2 h postexposure. Since Bax:VDAC interactions disrupt protective VDAC interactions with mitochondrial hexokinase (HXK), we also assessed VDAC:HXK associations following ethanol treatment and found such interactions were altered by ethanol treatment, but only at 2 h postexposure and only in the P4, ethanol-sensitive cerebellum. Ethanol neurotoxicity in cultured neuronal preparations was abolished by pharmacological inhibition of both VDAC and ANT interactions with Bax but not by a Bax channel blocker. Therefore, we conclude that, at this age, within the constraints of our experimental model, a primary mode of Bax-induced initiation of the apoptosis cascade following ethanol insult involves interactions with proteins of the PTP complex and not channel formation independent of PTP constituents.

Mechanistic insights into neurotoxicity induced by anesthetics in the developing brain

Compelling evidence has shown that exposure to anesthetics used in the clinic can cause neurodegeneration in the mammalian developing brain, but the basis of this is not clear. Neurotoxicity induced by exposure to anesthestics in early life involves neuroapoptosis and impairment of neurodevelopmental processes such as neurogenesis, synaptogenesis and immature glial development. These effects may subsequently contribute to behavior abnormalities in later life. In this paper, we reviewed the possible mechanisms of anesthetic-induced neurotoxicity based on new in vitro and in vivo findings. Also, we discussed ways to protect against anesthetic-induced neurotoxicity and their implications for exploring cellular and molecular mechanisms of neuroprotection. These findings help in improving our understanding of developmental neurotoxicology and in avoiding adverse neurological outcomes in anesthesia practice.

Postnatal exposure to trichloroethylene alters glutathione redox homeostasis, methylation potential, and neurotrophin expression in the mouse hippocampus

Previous studies have shown that continuous exposure throughout gestation until the juvenile period to environmentally relevant doses of trichloroethylene (TCE) in the drinking water of MRL+/+ mice promoted adverse behavior associated with glutathione depletion in the cerebellum indicating increased sensitivity to oxidative stress. The purpose of this study was to extend our findings and further characterize the impact of TCE exposure on redox homeostasis and biomarkers of oxidative stress in the hippocampus, a brain region prone to oxidative stress. Instead of a continuous exposure, the mice were exposed to water only or two environmentally relevant doses of TCE in the drinking water postnatally from birth until 6 weeks of age. Biomarkers of plasma metabolites in the transsulfuration pathway and the transmethylation pathway of the methionine cycle were also examined. Gene expression of neurotrophins was examined to investigate a possible relationship between oxidative stress, redox imbalance and neurotrophic factor expression with TCE exposure. Our results show that hippocampi isolated from male mice exposed to TCE showed altered glutathione redox homeostasis indicating a more oxidized state. Also observed was a significant, dose dependent increase in glutathione precursors. Plasma from the TCE treated mice showed alterations in metabolites in the transsulfuration and transmethylation pathways indicating redox imbalance and altered methylation capacity. 3-Nitrotyrosine, a biomarker of protein oxidative stress, was also significantly higher in plasma and hippocampus of TCE-exposed mice compared to controls. In contrast, expression of key neurotrophic factors in the hippocampus (BDNF, NGF, and NT-3) was significantly reduced compared to controls. Our results demonstrate that low-level postnatal and early life TCE exposure modulates neurotrophin gene expression in the mouse hippocampus and may provide a mechanism for TCE-mediated neurotoxicity.

Neuroprotection with metformin and thymoquinone against ethanol-induced apoptotic neurodegeneration in prenatal rat cortical neurons

Background

Exposure to ethanol during early development triggers severe neuronal death by activating multiple stress pathways and causes neurological disorders, such as fetal alcohol effects or fetal alcohol syndrome. This study investigated the effect of ethanol on intracellular events that predispose developing neurons for apoptosis via calcium-mediated signaling. Although the underlying molecular mechanisms of ethanol neurotoxicity are not completely determined, mitochondrial dysfunction, altered calcium homeostasis and apoptosis-related proteins have been implicated in ethanol neurotoxicity. The present study was designed to evaluate the neuroprotective mechanisms of metformin (Met) and thymoquinone (TQ) during ethanol toxicity in rat prenatal cortical neurons at gestational day (GD) 17.5.

Results

We found that Met and TQ, separately and synergistically, increased cell viability after ethanol (100 mM) exposure for 12 hours and attenuated the elevation of cytosolic free calcium [Ca²⁺]_c. Furthermore, Met and TQ maintained normal physiological mitochondrial transmembrane potential (Δψ_M), which is typically lowered by ethanol exposure. Increased cytosolic free [Ca²⁺]_c and lowered mitochondrial transmembrane potential after ethanol exposure significantly decreased the expression of a key anti-apoptotic protein (Bcl-2), increased expression of Bax, and stimulated the release of cytochrome-c from mitochondria. Met and TQ treatment inhibited the apoptotic cascade by increasing Bcl-2 expression. These compounds also repressed the activation of caspase-9 and caspase-3 and reduced the cleavage of PARP-1. Morphological conformation of cell death was assessed by TUNEL, Fluoro-Jade-B, and PI staining. These staining methods demonstrated more cell death after ethanol treatment, while Met, TQ or Met plus TQ prevented ethanol-induced apoptotic cell death.

Conclusion

These findings suggested that Met and TQ are strong protective agents against ethanol-induced neuronal apoptosis in primary rat cortical neurons. The collective data demonstrated that Met and TQ have the potential to ameliorate ethanol neurotoxicity and revealed a possible protective target mechanism for the damaging effects of ethanol during early brain development.

Differential effects of ethanol on c-jun N-terminal kinase, 14-3-3 proteins, and Bax in postnatal day 4 and postnatal day 7 rat cerebellum

These studies investigated ethanol effects on upstream cellular elements and interactions which contribute to Bax-related apoptosis in neonatal rat cerebellum at ages of peak ethanol sensitivity (postnatal day 4 [P4]), compared to later ages of relative resistance (P7). Analyses were made of basal levels of the pro-apoptotic c-jun N-terminal kinase (JNK), Bax, and the 14-3-3 anchoring proteins, as well as the responsiveness of these substances to ethanol at P4 versus P7. Dimerization of Bax with 14-3-3 was also investigated at the two ages following ethanol treatment, a process which sequesters Bax in the cytosol, thus inhibiting its mitochondrial translocation and disruption of the mitochondrial membrane potential. Cultured cerebellar granule cells were used to examine the protective potential of JNK inhibition on ethanol-mediated cell death. Basal levels of JNK were significantly higher at P4 than P7, but no differences in the other proteins were found. Activated JNK, and cytosolic and mitochondrially-translocated Bax were increased in P4 but not P7 animals following ethanol exposure, while protective 14-3-3 proteins were increased only at P7. Ethanol treatment resulted in decreases in Bax:14-3-3 heterodimers at P4, but not at P7. Inhibition of JNK activity in vitro provided partial protection against ethanol neurotoxicity. Thus, differential temporal vulnerability to ethanol in this CNS region correlates with differences in both levels of apoptosis-related substances (e.g., JNK), and differential cellular responsiveness, favoring apoptosis at the most sensitive age and survival at the resistant age. The upstream elements contributing to this vulnerability can be targets for future therapeutic strategies.

Protection of neurons and microglia against ethanol in a mouse model of fetal alcohol spectrum disorders by peroxisome proliferator-activated receptor-γ agonists

Fetal alcohol spectrum disorders (FASD) result from ethanol exposure to the developing fetus and are the most common cause of mental retardation in the United States. These disorders are characterized by a variety of neurodevelopmental and neurodegenerative anomalies which result in significant lifetime disabilities. Thus, novel therapies are required to limit the devastating consequences of FASD. Neuropathology associated with FASD can occur throughout the central nervous system (CNS), but is particularly well characterized in the developing cerebellum. Rodent models of FASD have previously demonstrated that both Purkinje cells and granule cells, which are the two major types of neurons in the cerebellum, are highly susceptible to the toxic effects of ethanol. The current studies demonstrate that ethanol decreases the viability of cultured cerebellar granule cells and microglial cells. Interestingly, microglia have dual functionality in the CNS. They provide trophic and protective support to neurons. However, they may also become pathologically activated and produce inflammatory molecules toxic to parenchymal cells including neurons. The findings in this study demonstrate that the peroxisome proliferator-activated receptor-γ agonists 15-deoxy-Δ12,15 prostaglandin J2 and pioglitazone protect cultured granule cells and microglia from the toxic effects of ethanol. Furthermore, investigations using a newly developed mouse model of FASD and stereological cell counting methods in the cerebellum elucidate that ethanol administration to neonates is toxic to both Purkinje cell neurons as well as microglia, and that in vivo administration of PPAR-γ agonists protects these cells. In composite, these studies suggest that PPAR-γ agonists may be effective in limiting ethanol-induced toxicity to the developing CNS.