Project description:While immune responses during nervous system injury and disease are well studied, exactly how primary neurons respond to immune signals is still largely unknown. We find that primary sympathetic neurons respond unexpectedly to interferon-gamma (IFN-γ), a cytokine released by immune cells in response to infection. While IFN-γ induces apoptosis in many cell types, it has the opposite effect on sympathetic neurons by protecting them from apoptotic stimuli. We found that IFN-γ addition enabled sympathetic neurons to become resistant to nerve growth factor (NGF) deprivation- or pan-kinase inhibition-induced apoptosis. In investigating how interferon modulates the apoptotic pathway, we discovered that c-jun phosphorylation and Bim induction in response to NGF deprivation were unchanged with IFN-γ. Downstream of the mitochondria, however, IFN-γ blocked cytochrome c release and caspase-3 activation in NGF-deprived neurons. Microinjection of cytochrome c into XIAP-/- neurons revealed no difference in cell death with IFN-γ addition, demonstrating a role for IFN-γ at the point of mitochondria permeabilization. Levels of Bax and Bcl-XL, molecules that help regulate mitochondrial permeabilization, were unchanged. These results identify Bax activation as the likely point at which IFN-γ acts to inhibit neuronal apoptosis.
Project description:Scrub typhus is a life-threatening disease caused by Orientia tsutsugamushi, a bacterium that mainly infects endothelial cells in vitro and in vivo. Evidence suggests that the interaction of O. tsutsugamushi with myeloid cells may play a pivotal role in O. tsutsugamushi infection. We showed here that O. tsutsugamushi intensively replicated within human monocyte-derived macrophages. Bacterial organisms stimulated the expression of a large panel of genes including type I interferon, interferon-stimulated, inflammatory, apoptosis-related genes and induced an M1-type gene response in macrophages. This transcriptional signature was accompanied by functional consequences such as the release of inflammatory cytokines such as Tumor Necrosis Factor and interleukin-gamma. Live O. tsutsugamushi organisms were necessary for type I interferon response and, to a lesser degree, to inflammatory response. As interferon-gamma is known to elicit M1 polarization, we assessed the effect of interferon-gamma on O. tsutsugamushi fate in macrophages. Exogenous interferon-gamma partly inhibited O. tsutsugamushi replication within macrophages. Our results suggest that the inflammatory response induced by O. tsutsugamushi may account for the local and systemic inflammation observed in scrub typhus and that interferon-gamma may be useful as an adjuvant treatment of patients with scrub typhus. Macrophages (4 M-CM-^W 10.5 cells per assay) were incubated with O. tsutsugamushi at a bacterium-to-cell ratio of 20:1 for 8 hours. RNA samples (four samples per experimental condition) were processed for microarray analysis.
Project description:The objective of this study was to compare the ability of mice that lack STAT1 to resolve a neurotropic viral challenge, and to assess the ability of neurons obtained from these mice to be effectively cleared of virus by interferon gamma For the array, primary neurons were isolated from embryonic mice, grown as pure cultures, exposed to recombinant interferon gamma for 3, 6 or 24 hours and harvested for microarray analysis to identify and compare the gene profiles between wild type and STAT1 knockout neurons.
Project description:Scrub typhus is a life-threatening disease caused by Orientia tsutsugamushi, a bacterium that mainly infects endothelial cells in vitro and in vivo. Evidence suggests that the interaction of O. tsutsugamushi with myeloid cells may play a pivotal role in O. tsutsugamushi infection. We showed here that O. tsutsugamushi intensively replicated within human monocyte-derived macrophages. Bacterial organisms stimulated the expression of a large panel of genes including type I interferon, interferon-stimulated, inflammatory, apoptosis-related genes and induced an M1-type gene response in macrophages. This transcriptional signature was accompanied by functional consequences such as the release of inflammatory cytokines such as Tumor Necrosis Factor and interleukin-gamma. Live O. tsutsugamushi organisms were necessary for type I interferon response and, to a lesser degree, to inflammatory response. As interferon-gamma is known to elicit M1 polarization, we assessed the effect of interferon-gamma on O. tsutsugamushi fate in macrophages. Exogenous interferon-gamma partly inhibited O. tsutsugamushi replication within macrophages. Our results suggest that the inflammatory response induced by O. tsutsugamushi may account for the local and systemic inflammation observed in scrub typhus and that interferon-gamma may be useful as an adjuvant treatment of patients with scrub typhus.
Project description:Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Interferon-gamma may interfere with the growth of tumor cells and slow the growth of the tumor. Combining more than one drug with interferon-gamma may kill more tumor cells. This phase I/II trial is studying the side effects and best dose of giving fluorouracil together with phenylbutyrate, indomethacin, and interferon-gamma and to see how well it works in treating patients with stage IV colorectal cancer
Project description:Developing sympathetic neurons depend on nerve growth factor (NGF) for survival and die by apoptosis after NGF withdrawal. This process requires de novo gene expression but only a small number of genes induced by NGF deprivation have been identified so far. We have used Affymetrix Exon arrays to study the pattern of expression of all known genes in sympathetic neurons deprived of NGF. We identified 415 up- and 813 down-regulated genes, including most of the genes previously known to be regulated in this system. By including a mixed lineage kinase (MLK) inhibitor, CEP-11004, in our experimental design we identified which of the genes induced after NGF withdrawal are potential targets of the MLK-JNK-c-Jun pathway. A detailed Gene Ontology and functional enrichment analysis also identified genetic pathways, such as the ER unfolded protein response, that are highly enriched and overrepresented amongst the genes expressed after NGF withdrawal whilst hierarchical cluster analysis revealed four major patterns of gene expression. Five genes not previously studied in sympathetic neurons - trb3, ddit3, txnip, ndrg1 and mxi1 - were validated by real time-PCR. The proteins encoded by these genes also increased in level after NGF withdrawal and this increase was prevented by CEP-11004, suggesting that these genes are potential targets of the MLK-JNK-c-Jun pathway. Overall, our microarray data gives a comprehensive overview of, and provides new information about, signalling pathways and transcription factors that are regulated by NGF withdrawal and identifies potential targets of the MLK-JNK-c-Jun pathway in sympathetic neurons
Project description:The transcription factor Egr3 has been shown to have a cell autonomous role in sympathetic nervous system (SNS) development. We utilized microarray analysis to identify potential downstream target genes deregulated with loss of Egr3. Both conditions were in the null Bax background to prevent apoptosis and therefore mitigate identification of apoptosis related genes. Our analysis identified genes involved in biological processes that were expected such as SNS development and axonogenesis as well as those that were unexpected such as dendritogenesis and axon guidance. This led us to investigate whether Egr3 is important in these unexpected biological processes within sympathetic neurons. Total RNA was obtained from superior cervical ganglion (SCG) dissected from P0 mice with the genotype of Egr3+/+; Bax-/- or Egr3-/-; Bax-/-. Each genotype had 3 samples each.
Project description:The transcription factor Egr3 has been shown to have a cell autonomous role in sympathetic nervous system (SNS) development. We utilized microarray analysis to identify potential downstream target genes deregulated with loss of Egr3. Both conditions were in the null Bax background to prevent apoptosis and therefore mitigate identification of apoptosis related genes. Our analysis identified genes involved in biological processes that were expected such as SNS development and axonogenesis as well as those that were unexpected such as dendritogenesis and axon guidance. This led us to investigate whether Egr3 is important in these unexpected biological processes within sympathetic neurons.
Project description:Understanding factors that drive development of the sympathetic neuron is crucial to development of potential therapies for neuroblastoma. Here, we identify a key cell autonomous role for the LIM homeodomain transcription factor ISL1 for survival, proliferation and differentiation of sympathetic neurons throughout development. Chromatin immunoprecipitation assays performed utilizing antibody to ISL1 in chromatin extracts from sympathetic neurons demonstrated that ISL1 directly binds genomic regions within several genes critical for sympathetic neuron development and function, including subunits of the Insm1, Lmo1,Tlx3 and Prox1. Our studies represent in vivo ChIP-seq studies for sympathetic neurons which provide a basis for further exploration of factors critical to sympathetic neurons development and function .