Project description:Purpose: Nucleotide excision repair (NER) in mammalian cells requires the xeroderma pigmentosum group A protein (XPA) as a core factor. Remarkably, XPA and other NER proteins have been detected by chromatin immunoprecipitation at some active promoters, and NER deficiency is reported to influence the activated transcription of selected genes. However, the global influence of XPA on transcription in human cells has not been determined. Methods: We analyzed the human transcriptome by RNA sequencing (RNA-Seq). Four genetically matched human cell line pairs deficient or proficient in XPA were analyzed Results: Of the ~14,000 genes transcribed in each cell line, 325 genes (2%) had a significant XPA-dependent directional change in gene expression that was common to all four pairs (with a false discovery rate of 0.05). These genes were enriched in pathways for the maintenance of mitochondria. Only 27 genes were different by more than 1.5-fold. The most significant hits were AKR1C1 and AKR1C2, involved in steroid hormone metabolism. AKR1C2 protein was lower in all of the immortalized XPA-deficient cells. Retinoic acid treatment led to modest XPA-dependent activation of some genes with transcription-related functions. Conclusions: We conclude that XPA status does not globally influence human gene transcription. However, XPA significantly influences expression of a small subset of genes important for mitochondrial functions and steroid hormone metabolism. The results may help explain defects in neurological function and sterility in individuals with xeroderma pigmentosum.
Project description:We compared the transcriptomic response to UVC radiation in widltype (N2), DNA repair-deficient (xpa-1), and germ cell-deficient (glp-1) young adult nematodes. We were interested in the wildtype response to this stressor, and postulated that the early (3h post-exposure) difference might be different in nucleotide excision repair-deficient (xpa-1) nematodes. We also hypothesized that the response would be different in young adults composed entirely of somatic cells (glp-1 strain at this temperature), compared to germ cell-bearing and gravid young adults (N2 and xpa-1). Finally, we compared constitutive differences in gene expression between the strains.
Project description:Adult neurogenesis, found in two neurogenic regions of the brain, has profound roles in neural plasticity and brain function. A hallmark feature of neurodegeneration is neuroinflammation, which can either enhance or inhibit neurogenesis depending on the context of the brain microenvironment. The consequences of deficient DNA repair in adult neurogenesis and neuroinflammation are poorly understood despite their potential relevance for homeostasis. We previously reported that loss of NEIL1, an important DNA glycosylase involved in DNA base excision repair, is associated with deficiencies in spatial memory, olfaction, and protection against ischemic stroke in mice. Here, we show that Neil1-/- mice display an anxiety-mediated behavior in the open field test, a deficient recognitive memory in novel object recognition and increased neuroinflammatory response under basal conditions. Further, mice lacking NEIL1 have decreased neurogenesis and deficient resolution of neuroinflammation following gamma irradiation (IR)-induced stress compared to WT mice. Neil1-/- IR-exposed mice also exhibit increased DNA damage and apoptosis in the hippocampus. Interestingly, behavioral tests two weeks after IR showed impaired stress response in the Neil1-/- mice. Our data indicate that NEIL1 plays an important role in adult neurogenesis and in the resolution of neuroinflammation.
Project description:We are investigating the transcriptional response of mice that are wt or null for Aag in response to alkylating agent MMS; We used microarrays to detail the global programme of gene expression response due to MMS exposure in a DNA repair proficient or deficient mouse Experiment Overall Design: Mice (WT and Aag null) were treated with MMS and livers extracted at 6, 12, 24, and 48 hours
Project description:Background: The ability of an organism to repair damages to DNA is inextricably linked to aging and cancer. We have characterized and compared the transcriptome of C. elegans mutants deficient in DNA base excision repair, nucleotide excision repair or both to elucidate the transcriptional changes incurred by the reduction of these repair pathways. Results: The gene expression signatures from nth-1, xpa-1 and nth-1;xpa-1 are deciphered. We find that the single mutants are more similar in overall transcriptomic activity compared to the double mutant and their corresponding wild-type (N2). Interestingly, of the enriched Gene Ontology terms for respective mutants are aging and proteolysis for nth-1, aging, energy production and unfolded protein response for xpa-1, and DNA repair and regulation of M-phase for nth-1;xpa-1. We also find striking similarities between the biological processes found to be enriched in the single mutants, which show a shared response in genes associated with aging and insulin signaling. Loss of either BER or NER induces an oxidative stress response, but does not confer resistance to heat shock. Conclusion: Taken together, our study provides a general overview about the global transcriptional changes in the absence of nth-1, xpa-1 and nth-1;xpa-1. Our results also point to a two-tiered global response to combat the effects of decreased DNA repair capacity.
Project description:Background: The ability of an organism to repair DNA damage is implicated in carcinogenesis and aging. Interestingly expression profiling of Nucleotide Excision Repair (NER) deficient segmental progeroid mice revealed gene expression changes resembling these observed in aged wild type animals. Our previous transcriptional profiling of NER-deficient C. elegans xpa-1 mutant showed overrepresentation of genes involved in lifespan determination and upregulation of several oxidative stress response genes (Fensgard et al. Aging 2010). However, since an independent study performed by Boyd and coworkers (Boyd et al. Mut Res 2010) showed limited number of changes in xpa-1 mutant. Therefore to independently validate that transcriptome modulation does take place in xpa-1 mutants, we performed another global gene expression profiling based on 5 independent biological replicates allowing more stringent statistical analysis. Results: In agreement with what was observed by Boyd and coworkers (Boyd et al. Mut Res 2010) current transcriptomic analysis detected fewer changes in xpa-1 C. elegans mutant with only a few genes regulated more than 4-fold. Nevertheless, Gene Ontology (GO) enrichment analysis performed on statistically significantly regulated unique protein coding genes revealed overrepresentation of aging gene cluster. Moreover, as before, overexpression of several genes involved in oxidative stress responses was detected. Conclusion: More stringent statistical analysis predictably resulted in a smaller number of regulated genes and thus overrepresented GOs comparing to the earlier paper. However, major conclusions of the previous study can be still regarded as valid, as the most important aging GO is still overrepresented. Background: The ability of an organism to repair DNA damage is implicated in carcinogenesis and aging. Interestingly expression profiling of Nucleotide Excision Repair (NER) deficient segmental progeroid mice revealed gene expression changes resembling these observed in aged wild type animals. Our previous transcriptional profiling of NER-deficient C. elegans xpa-1 mutant showed overrepresentation of genes involved in lifespan determination and upregulation of several oxidative stress response genes (Fensgard et al. Aging 2010). However, since an independent study performed by Boyd and coworkers (Boyd et al. Mut Res 2010) showed limited number of changes in xpa-1 mutant. Therefore to independently validate that transcriptome modulation does take place in xpa-1 mutants, we performed another global gene expression profiling based on 5 independent biological replicates allowing more stringent statistical analysis. Results: In agreement with what was observed by Boyd and coworkers (Boyd et al. Mut Res 2010) current transcriptomic analysis detected fewer changes in xpa-1 C. elegans mutant with only a few genes regulated more than 4-fold. Nevertheless, Gene Ontology (GO) enrichment analysis performed on statistically significantly regulated unique protein coding genes revealed overrepresentation of aging gene cluster. Moreover, as before, overexpression of several genes involved in oxidative stress responses was detected. Conclusion: More stringent statistical analysis predictably resulted in a smaller number of regulated genes and thus overrepresented GOs comparing to the earlier paper. However, major conclusions of the previous study can be still regarded as valid, as the most important aging GO is still overrepresented. Background: The ability of an organism to repair DNA damage is implicated in carcinogenesis and aging. Interestingly expression profiling of Nucleotide Excision Repair (NER) deficient segmental progeroid mice revealed gene expression changes resembling these observed in aged wild type animals. Our previous transcriptional profiling of NER-deficient C. elegans xpa-1 mutant showed overrepresentation of genes involved in lifespan determination and upregulation of several oxidative stress response genes (Fensgard et al. Aging 2010). However, since an independent study performed by Boyd and coworkers (Boyd et al. Mut Res 2010) showed limited number of changes in xpa-1 mutant. Therefore to independently validate that transcriptome modulation does take place in xpa-1 mutants, we performed another global gene expression profiling based on 5 independent biological replicates allowing more stringent statistical analysis. Results: In agreement with what was observed by Boyd and coworkers (Boyd et al. Mut Res 2010) current transcriptomic analysis detected fewer changes in xpa-1 C. elegans mutant with only a few genes regulated more than 4-fold. Nevertheless, Gene Ontology (GO) enrichment analysis performed on statistically significantly regulated unique protein coding genes revealed overrepresentation of aging gene cluster. Moreover, as before, overexpression of several genes involved in oxidative stress responses was detected. Conclusion: More stringent statistical analysis predictably resulted in a smaller number of regulated genes and thus overrepresented GOs comparing to the earlier paper. However, major conclusions of the previous study can be still regarded as valid, as the most important aging GO is still overrepresented. Activation of oxidative stress-responses and downregulation of insulin-like signaling (ILS) is seen in Nucleotide Excision Repair (NER) deficient segmental progeroid mice. Evidence suggests that this is a survival response to persistent transcription-blocking DNA damage, although the relevant lesions have not been identified. Here we provide evidence for transcriptional reprogramming in NER-deficient C. elegans xpa-1 by transcriptomic and proteomic approaches. This reprograming is accompanied by increased intracellular ROS and ATP levels and lifespan shortening in xpa-1 mutant. Moreover we show that Base Excision Repair DNA glycosylase NTH-1 is upstream form the signaling events leading to transcriptomic changes, as its downregulation reverses overexpression of sod-3, gst-4 and aqp-1 genes, reduces intracellular ROS and ATP levels and reverses lifespan shortening observed in xpa-1 mutant. Surprisingly, however, these responses appear to not depend on cyclopurine levels, since these lesions are lower in xpa-1 C. elegans mutant than in the wild type. Finally, we also explore here which other upstream factors are necessary for transcriptional reprograming in xpa-1 mutant. Untreated Caenorhabditis elegans mutant deficient in xpa-1 and the wild type N2 strain were subjected to transcriptome analysis using Affymetrix platform. For each sample group five replicates were analyzed.
Project description:Single Center, open label, Phase I-II trial designed to test the safety and efficacy of the combination of Ataluren and Pembrolizumab for the treatment of metastatic mismatch repair deficient and proficient colorectal adenocarcinoma and metastatic mismatch repair deficient endometrial carcinoma.
Project description:Cockayne syndrome (CS) is a photosensitive, DNA repair disorder associated with progeria caused by a defect in the transcription-coupled repair (TCR) subpathway of nucleotide excision repair (NER). Here, complete inactivation of NER in Csbm/m/Xpa-/- mutants causes a phenotype that reliably mimics the human progeroid CS syndrome. Newborn Csbm/m/Xpa-/- mice display attenuated growth, progressive neurological dysfunction, retinal degeneration, cachexia, kyphosis and die before weaning. To investigate whether a disturbance in growth and metabolism could explain the pronounced accelerated organismal deterioration seen in Csbm/m/Xpa-/- mice, we evaluated the liver transcriptome of 15-day old wt, single and double mutant mice (n=4). At this age, the Csbm/m/Xpa-/- pups have not yet become cachectic. Mouse liver transcriptome analysis and several physiological endpoints revealed systemic suppression of the GH/IGF1 somatotroph axis and oxidative metabolism, increased antioxidant responses, hypoglycemia together with hepatic glycogen and fat accumulation. Broad genome-wide parallels between Csbm/m/Xpa-/- and naturally aged mouse liver transcriptomes suggested that these changes are intrinsic to natural aging and the DNA repair-deficient mice. Importantly, wild type (wt) mice exposed to a low dose of chronic genotoxic stress and adult Csbm/m mutant mice recapitulated this response, thereby pointing to a novel link between genome instability and the age-related decline of the somatotroph axis.
Project description:Background: The ability of an organism to repair DNA damage is implicated in carcinogenesis and aging. Interestingly expression profiling of Nucleotide Excision Repair (NER) deficient segmental progeroid mice revealed gene expression changes resembling these observed in aged wild type animals. Our previous transcriptional profiling of NER-deficient C. elegans xpa-1 mutant showed overrepresentation of genes involved in lifespan determination and upregulation of several oxidative stress response genes (Fensgard et al. Aging 2010). However, since an independent study performed by Boyd and coworkers (Boyd et al. Mut Res 2010) showed limited number of changes in xpa-1 mutant. Therefore to independently validate that transcriptome modulation does take place in xpa-1 mutants, we performed another global gene expression profiling based on 5 independent biological replicates allowing more stringent statistical analysis. Results: In agreement with what was observed by Boyd and coworkers (Boyd et al. Mut Res 2010) current transcriptomic analysis detected fewer changes in xpa-1 C. elegans mutant with only a few genes regulated more than 4-fold. Nevertheless, Gene Ontology (GO) enrichment analysis performed on statistically significantly regulated unique protein coding genes revealed overrepresentation of aging gene cluster. Moreover, as before, overexpression of several genes involved in oxidative stress responses was detected. Conclusion: More stringent statistical analysis predictably resulted in a smaller number of regulated genes and thus overrepresented GOs comparing to the earlier paper. However, major conclusions of the previous study can be still regarded as valid, as the most important aging GO is still overrepresented. Activation of oxidative stress-responses and downregulation of insulin-like signaling (ILS) is seen in Nucleotide Excision Repair (NER) deficient segmental progeroid mice. Evidence suggests that this is a survival response to persistent transcription-blocking DNA damage, although the relevant lesions have not been identified. Here we provide evidence for transcriptional reprogramming in NER-deficient C. elegans xpa-1 by transcriptomic and proteomic approaches. This reprograming is accompanied by increased intracellular ROS and ATP levels and lifespan shortening in xpa-1 mutant. Moreover we show that Base Excision Repair DNA glycosylase NTH-1 is upstream form the signaling events leading to transcriptomic changes, as its downregulation reverses overexpression of sod-3, gst-4 and aqp-1 genes, reduces intracellular ROS and ATP levels and reverses lifespan shortening observed in xpa-1 mutant. Surprisingly, however, these responses appear to not depend on cyclopurine levels, since these lesions are lower in xpa-1 C. elegans mutant than in the wild type. Finally, we also explore here which other upstream factors are necessary for transcriptional reprograming in xpa-1 mutant.