Programmed Cell Death 4 (<scp>PDCD</scp>4): A Novel Player in Ethanol‐Mediated Suppression of Protein Translation in Primary Cortical Neurons and Developing Cerebral Cortex

Narasimhan, Madhusudhanan; Rathinam, Marylatha; Riar, Amanjot Kaur; Patel, Dhyanesh A.; Mummidi, Srinivas; Yang, Hsin Shen; Colburn, Nancy H.; Henderson, George I.; Mahimainathan, Lenin

doi:10.1111/j.1530-0277.2012.01850.x

Cited by 19 publications

(41 citation statements)

References 62 publications

(83 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One study that appeared after Kennedy's (1984) review demonstrated that protein synthesis rates were significantly reduced in the brains of EtOH‐exposed rat embryos (Rawat, ). This was further confirmed in more recent studies, which established that the rate of protein synthesis reduction in the brain can be as much as 40% (Bonner et al., ; Narasimhan et al., ). The results of our meta‐analyses are consistent with this hypothesis: we found enrichment of genes involved in ribosome biogenesis (or more generally ribonucleoprotein complex biogenesis) in our down‐regulated “all,” “acute,” and “prenatal” meta‐signatures.…”

Section: Discussionmentioning

confidence: 55%

Meta‐Analysis of Gene Expression Patterns in Animal Models of Prenatal Alcohol Exposure Suggests Role for Protein Synthesis Inhibition and Chromatin Remodeling

Rogić

Wong

Pavlidis

2016

Alcoholism Clin & Exp Res

View full text Add to dashboard Cite

Background Prenatal alcohol exposure (PAE) can result in an array of morphological, behavioural and neurobiological deficits that can range in their severity. Despite extensive research in the field and a significant progress made, especially in understanding the range of possible malformations and neurobehavioral abnormalities, the molecular mechanisms of alcohol responses in development are still not well understood. There have been multiple transcriptomic studies looking at the changes in gene expression after PAE in animal models, however there is a limited apparent consensus among the reported findings. In an effort to address this issue, we performed a comprehensive re-analysis and meta-analysis of all suitable, publically available expression data sets. Methods We assembled ten microarray data sets of gene expression after PAE in mouse and rat models consisting of samples from a total of 63 ethanol-exposed and 80 control animals. We re-analyzed each data set for differential expression and then used the results to perform meta-analyses considering all data sets together or grouping them by time or duration of exposure (pre- and post-natal, acute and chronic, respectively). We performed network and Gene Ontology enrichment analysis to further characterize the identified signatures. Results For each sub-analysis we identified signatures of differential expressed genes that show support from multiple studies. Overall, the changes in gene expression were more extensive after acute ethanol treatment during prenatal development than in other models. Considering the analysis of all the data together, we identified a robust core signature of 104 genes down-regulated after PAE, with no up-regulated genes. Functional analysis reveals over-representation of genes involved in protein synthesis, mRNA splicing and chromatin organization. Conclusions Our meta-analysis shows that existing studies, despite superficial dissimilarity in findings, share features that allow us to identify a common core signature set of transcriptome changes in PAE. This is an important step to identifying the biological processes that underlie the etiology of FASD.

show abstract

Section: Discussionmentioning

confidence: 55%

Meta‐Analysis of Gene Expression Patterns in Animal Models of Prenatal Alcohol Exposure Suggests Role for Protein Synthesis Inhibition and Chromatin Remodeling

Rogić

Wong

Pavlidis

2016

Alcoholism Clin & Exp Res

View full text Add to dashboard Cite

show abstract

“…Our laboratory has previously shown that PDCD4 plays a critical role in ethanol-induced dysregulation of protein synthesis in PCNs and in utero binge alcohol model [11]. Since neuron development is progeny dependent, in the current study we investigated whether ethanol-induced PDCD4 changes are conserved in mitotic neuroblasts, the immediate precursor of neurons.…”

Section: Resultsmentioning

confidence: 95%

Ethanol-Induced Transcriptional Activation of Programmed Cell Death 4 (Pdcd4) Is Mediated by GSK-3β Signaling in Rat Cortical Neuroblasts

et al. 2014

Self Cite

View full text Add to dashboard Cite

Ingestion of ethanol (ETOH) during pregnancy induces grave abnormalities in developing fetal brain. We have previously reported that ETOH induces programmed cell death 4 (PDCD4), a critical regulator of cell growth, in cultured fetal cerebral cortical neurons (PCNs) and in the cerebral cortex in vivo and affect protein synthesis as observed in Fetal Alcohol Spectrum Disorder (FASD). However, the mechanism which activates PDCD4 in neuronal systems is unclear and understanding this regulation may provide a counteractive strategy to correct the protein synthesis associated developmental changes seen in FASD. The present study investigates the molecular mechanism by which ethanol regulates PDCD4 in cortical neuroblasts, the immediate precursor of neurons. ETOH treatment significantly increased PDCD4 protein and transcript expression in spontaneously immortalized rat brain neuroblasts. Since PDCD4 is regulated at both the post-translational and post-transcriptional level, we assessed ETOH’s effect on PDCD4 protein and mRNA stability. Chase experiments demonstrated that ETOH does not significantly impact either PDCD4 protein or mRNA stabilization. PDCD4 promoter-reporter assays confirmed that PDCD4 is transcriptionally regulated by ETOH in neuroblasts. Given a critical role of glycogen synthase kinase 3β (GSK-3β) signaling in regulating protein synthesis and neurotoxic mechanisms, we investigated the involvement of GSK-3β and showed that multifunctional GSK-3β was significantly activated in response to ETOH in neuroblasts. In addition, we found that ETOH-induced activation of PDCD4 was inhibited by pharmacologic blockade of GSK-3β using inhibitors, lithium chloride (LiCl) and SB-216763 or siRNA mediated silencing of GSK-3β. These results suggest that ethanol transcriptionally upregulates PDCD4 by enhancing GSK-3β signaling in cortical neuroblasts. Further, we demonstrate that canonical Wnt-3a/GSK-3β signaling is involved in regulating PDCD4 protein expression. Altogether, we provide evidence that GSK-3β/PDCD4 network may represent a critical modulatory point to manage the protein synthetic anomalies and growth aberrations of neural cells seen in FASD.

show abstract

“…This is a well-established and documented primary neuronal culture system, which is essentially free of glia. Dual immunostaining with MAP2 (for neurons) and GFAP (for astrocytes) were performed and the isolation procedure reproducibly adopted yielded ~95% enriched neuronal culture [4,29]. Handling of animals was carried out according to the National Institutes of Health guidelines for the use and care of laboratory animals.…”

Section: Methodsmentioning

confidence: 99%

“…The in vitro experiments involving ETOH in the current study uses a clinically relevant dose, which is at or below to that used in other studies to elicit a range of neurotoxic responses including brain apoptotic responses in various neuron culture, mouse and rat models [4,23,29,30]. …”

Section: Methodsmentioning

confidence: 99%

Astrocytes Prevent Ethanol Induced Apoptosis of Nrf2 Depleted Neurons by Maintaining GSH Homeostasis

Narasimhan

Rathinam

Patel

et al. 2012

OJApo

Self Cite

View full text Add to dashboard Cite

Glutathione (GSH), a major cellular antioxidant protects cells against oxidative stress injury. Nuclear factor erythroid 2-related factor 2 (NFE2L2/Nrf2) is a redox sensitive master regulator of battery of antioxidant enzymes including those involved in GSH antioxidant machinery. Earlier we reported that ethanol (ETOH) elicits apoptotic death of primary cortical neurons (PCNs) which in partly due to depletion of intracellular GSH levels. Further a recent report from our laboratory illustrated that ETOH exacerbated the dysregulation of GSH and caspase mediated cell death of cortical neurons that are compromised in Nrf2 machinery (Narasimhan et al., 2011). In various experimental models of neurodegeneration, neuronal antioxidant defenses mainly GSH has been shown to be supported by astrocytes. We therefore sought to determine whether astrocytes can render protection to neurons against ETOH toxicity, particularly when the function of Nrf2 is compromised in neurons. The experimental model consisted of co-culturing primary cortical astrocytes (PCA) with Nrf2 downregulated PCNs that were exposed with 4 mg/mL ETOH for 24 h. Monochlorobimane (MCB) staining followed by FACS analysis showed that astrocytes blocked ETOH induced GSH decrement in Nrf2-silenced neurons as opposed to exaggerated GSH depletion in Nrf2 downregulated PCNs alone. Similarly, the heightened activation of caspase 3/7 observed in Nrf2-compromised neurons was attenuated when co-cultured with astrocytes as measured by luminescence based caspase Glo assay. Furthermore, annexin-V-FITC staining followed by FACS analysis revealed that Nrf2 depleted neurons showed resistance to ETOH induced neuronal apoptosis when co-cultured with astrocytes. Thus, the current study identifies ETOH induced dysregulation of GSH and associated apoptotic events observed in Nrf2-depleted neurons can be blocked by astrocytes. Further our results suggest that this neuroprotective effect of astrocyte despite dysfunctional Nrf2 system in neurons could be compensated by astrocytic GSH supply.

show abstract

Programmed Cell Death 4 (PDCD4): A Novel Player in Ethanol‐Mediated Suppression of Protein Translation in Primary Cortical Neurons and Developing Cerebral Cortex

Cited by 19 publications

References 62 publications

Meta‐Analysis of Gene Expression Patterns in Animal Models of Prenatal Alcohol Exposure Suggests Role for Protein Synthesis Inhibition and Chromatin Remodeling

Meta‐Analysis of Gene Expression Patterns in Animal Models of Prenatal Alcohol Exposure Suggests Role for Protein Synthesis Inhibition and Chromatin Remodeling

Ethanol-Induced Transcriptional Activation of Programmed Cell Death 4 (Pdcd4) Is Mediated by GSK-3β Signaling in Rat Cortical Neuroblasts

Astrocytes Prevent Ethanol Induced Apoptosis of Nrf2 Depleted Neurons by Maintaining GSH Homeostasis

Contact Info

Product

Resources

About