Project description:The DNA repair protein, Cockayne syndrome group B (CSB), has been recently identified as a promising anticancer target. Suppression, by antisense technology, of this protein causes devastating effects on tumor cells viability, through a massive induction of apoptosis, while being non-toxic to non-transformed cells. To gain insights into the mechanisms underlying the pro-apoptotic effects observed after CSB ablation, global gene expression patterns were determined, to identify genes that were significantly differentially regulated as a function of CSB expression. The one-color Agilent microarray platform was used. The study revealed that response to endoplasmic reticulum stress and response to unfolded proteins were ranked top amongst the cellular processes affected by CSB suppression.
Project description:Lipoic acid induced endoplasmic reticulum stress-mediated apoptosis in rat hepatoma cells:identification of new ER stress aggravator (ERSA)
Project description:The hepatitis E virus (HEV), a non enveloped RNA virus, causes viral hepatitis. The viral open reading frame 2 (ORF2) protein represents the capsid protein of HEV which is known to cause endoplasmic reticulum stress in ORF2 expressing cells. The initiation of endoplasmic reticulum stress induced apoptosis mainly involves the transcriptional activation of pro-apoptotic gene CHOP which will further trigger the major apoptotic pathways. However, the activation of CHOP by ORF2 protein in this study does not induce apoptotic markers such as Bax translocation to mitochondria. We have used the Affymetrix microarray platform to screen the pro-apoptotic effects induced by the expression of ORF2 protein in human hepatic cell lines (Huh7). The Huh7 cells were transduced either with recombinant adenovirus encoding the HEV ORF2 (Ad-ORF2) or an adenovirus encoding the green fluorescent protein (Ad-GFP). The array results consistently showed an ORF2 specific induction of mRNA corresponding to the chaperones Hsp72, Hsp70B’ and co-chaperone Hsp40. These studies provide further mechanisms of the ER stress mediated pro apoptotic effects caused by the ORF2 protein and its potential role for the activation of anti-apoptotic activity of the host cell. We used microarray to screen the host genes were regulated by the expression of the hepatitis E virus capsid protein. Huh7 cells transduced with Ad-GFP (control) or with Ad-HEV ORF2.
Project description:Pharmacological intervention of redox balance in cancer cells often results in oxidative stress-mediated apoptosis, attracting much attention for the development of a new generation of targeted therapy in cancer. However, little is known about mechanisms underlying the conversion from oxidative signaling to downstream activities leading cells to death. We here report a systematic detection of transcriptome changes in response to oxidative signals generated in leukemia cells upon fenretinide treatment, implicating the occurrence of numerous stress-responsive events during the fenretinide induced apoptosis, such as redox response, endoplasmic reticulum stress/unfolded protein response, translational repression and proteasome activation. Moreover, the configuration of these relevant events is primarily orchestrated by stress responsive transcription factors, as typically highlighted by NF-E2-related factor-2 (NRF2) and heat shock factor 1 (HSF1). Several lines of evidence suggest that the coordinated regulation of these transcription factors and thus their downstream genes are involved in converting oxidative signaling into downstream stress-responsive events regulating pro-apoptotic and apoptotic activities at the temporal and spatial levels, typifying oxidative stress-mediated programmed death rather than survival in cancer cells. This study provides a roadmap for understanding oxidative stress-mediated apoptosis in cancer cells, which may be further developed into more sophisticated therapeutic protocols, as implicated by synergistic induction of cell apoptosis using proteasome inhibitors with fenretinide. Time-series experiment, fenretinide treated NB4 cells at 19 time points (i.e., 0.25, 0.5, 1, 2, 4, 6, 8, 10, 12, 15, 18, 21, 24, 30, 36, 42, 48, 54 and 60 hours) and untreated NB4 cells at 4 time points (i.e., 0, 8, 12 and 15 hours).
Project description:Currently, more than 55 million people around the world suffer from dementia, and Alzheimer's disease-related dementia (ADRD) accounts for nearly 60-70% of all those cases. The spread of AD pathology and progressive neurodegeneration in the hippocampus and cerebral cortex is strongly correlated with cognitive decline in AD patients; however, the molecular underpinning of the ADRD causality is still unclear. Studies of postmortem AD brains and animal models of AD suggest that elevated endoplasmic reticulum (ER) stress may have a role in ADRD pathology through altered neurocellular homeostasis in brain regions associated with learning and memory. To study the ER stress-associated neurocellular response and its effects on neurocellular homeostasis and neurogenesis, we modeled an ER stress challenge using Thapsigargin (TG), a specific inhibitor of sarco/endoplasmic reticulum Ca2+ ATPase (SERCA), in induced pluripotent stem cell (iPSC)-derived neural stem cells (NSCs) of two individuals from our Mexican American Family Study (MAFS). High-content screening and transcriptomic analysis of the control and ER stress-challenged NSCs showed that NSC’s ER stress response resulted in a significant decline in NSC self-renewal and an increase in apoptosis and cellular oxidative stress. A total of 2300 genes were significantly (moderated t statistics FDR corrected p-value ≤ 0.05 and Fold Change absolute ≥ 2.0) differentially expressed (DE). Pathway enrichment and gene network analysis of DE genes suggests that all three unfolded protein response (UPR) pathways (PERK, IRE1, and ATF6) were significantly activated and cooperatively regulated the NSC’s transcriptional response to ER stress. Our results show that IRE1/XBP1 mediated transcriptional regulation of E2F1 and its downstream targets have a dominant role in inducing G1/S-phase cell cycle arrest in the ER stress-challenged NSCs. The ER stress-challenged NSCs also showed activation of CHOP-mediated apoptosis and dysregulation of synaptic plasticity and neurotransmitter homeostasis-associated genes. Overall, our results suggest that ER stress-associated attenuation of NSC self-renewal, increased apoptosis, and dysregulated synaptic plasticity and neurotransmitter homeostasis plausibly play a role in the causation of ADRD.
Project description:The aim of this study is to identify genes whose expression is under the control of IRE1A and IRE1B during a chronic proteotoxic endoplasmic reticulum stress induced by tunicamycin. The transcriptional response has been measured in separated shoot and root tissues from Arabidopsis seedlings.
Project description:The hepatitis E virus (HEV), a non enveloped RNA virus, causes viral hepatitis. The viral open reading frame 2 (ORF2) protein represents the capsid protein of HEV which is known to cause endoplasmic reticulum stress in ORF2 expressing cells. The initiation of endoplasmic reticulum stress induced apoptosis mainly involves the transcriptional activation of pro-apoptotic gene CHOP which will further trigger the major apoptotic pathways. However, the activation of CHOP by ORF2 protein in this study does not induce apoptotic markers such as Bax translocation to mitochondria. We have used the Affymetrix microarray platform to screen the pro-apoptotic effects induced by the expression of ORF2 protein in human hepatic cell lines (Huh7). The Huh7 cells were transduced either with recombinant adenovirus encoding the HEV ORF2 (Ad-ORF2) or an adenovirus encoding the green fluorescent protein (Ad-GFP). The array results consistently showed an ORF2 specific induction of mRNA corresponding to the chaperones Hsp72, Hsp70B’ and co-chaperone Hsp40. These studies provide further mechanisms of the ER stress mediated pro apoptotic effects caused by the ORF2 protein and its potential role for the activation of anti-apoptotic activity of the host cell.
Project description:Study of the effects of the VCP knockdown. VCP (p97, yeast cdc48) is a hexameric AAA ATPase involved in various cellular functions including degradation of proteins by the ubiquitin-proteasome system. We examine the consequences of the reduction of VCP levels after RNAi of VCP in HeLa cells. We find ~30 transcripts upregulated in a sequence independent manner. Those transcripts encode proteins involved in endoplasmic reticulum stress, apoptosis, and amino acid starvation.