Project description:Recently, Bailey et al (2016, Nature) defined four subtypes of pancreatic cancer that are associated with distinct histopathological characteristics and differential survival, namely, Squamous, Pancreatic Progenitor, Immunogenic, and ADEX (Aberrantly Differentiated Endocrine eXocrine). We set out to assess by RNASeq whether loss of CXCR2 was significantly associated with a specific PDAC subtype. Pancreatic tumors were harvested from KPC or KPC Cxcr2-/- mice at endpoint (n=5 v 5), RNA prepared, and RNASeq analysis carried out. Reads were analysed using the bcbio-nextgen framework (https://bcbio-nextgen.readthedocs.org/en/latest/). After quality control and adaptor trimming, reads were aligned to the mouse genome build (UCSC mouse mm10) using STAR. Counts for known genes were generated using the function featureCounts in the R/Bioconductor package \Rsubread\. The R/Bioconductor package edgeR was used to identify differentially expressed genes.
Project description:We report the application of bulk RNAseq of live cells from pancreas of KPC or KPC-OG genetic mice at 6 weeks of age. These sponteneous tumors were unperturbed otherwise until timepoint.
Project description:Plasmid carriage requires appropriate expression of the genes on the plasmid or host chromosome through cooperative transcriptional regulation. To clarify the impact of plasmid carriage on the host chromosome, we compared the chromosomal RNA maps of plasmid-free and plasmid-containing host strains using the incompatibility group P-7 archetype plasmid pCAR1, which is involved in carbazole degradation, and three distinct Pseudomonas strains. The possession of pCAR1 altered gene expression related to the iron acquisition systems in each host. Expression of the major siderophore pyoverdine was greater in plasmid-containing P. putida KT2440 and P. aeruginosa PAO1 than in the plasmid-free host strains, in part due to the expression of carbazole-degradative genes on pCAR1. The mexEFoprN operon encoding an efflux pump of the resistance-nodulation-cell division (RND) family was specifically upregulated by the carriage of pCAR1 in P. putida KT2440, whereas the expression of orthologous genes in the other species remained unaltered. Induction of the mexEFoprN genes increased the resistance of pCAR1-containing KT2440 to chloramphenicol compared to pCAR1-free KT2440. Our findings indicate that the possession of pCAR1 altered the growth rate of the host via the expression of genes on pCAR1 and the host chromosomes.
Project description:Antibiotic resistance associated with the expression of the clinically significant carbapenemases, IMP, KPC, and NDM and OXA-48 in Enterobacteriaceae is emerging as a worldwide calamity to health care. In Australia, IMP-producing Enterobacteriaceae is the most prevalent carbapenemase-producing Enterobacteriaceae (CPE). Genomic characteristics of such carbapenemase-producing Enterobacteriaceae (CPE) are well described, but the corresponding proteome is poorly characterised. We have thus developed a method to analyse dynamic changes in the proteome of CPE under antibiotic pressure. Specifically, we have investigated the effect of meropenem at sub-lethal concentrations to develop a better understanding of how antibiotic pressure leads to resistance. Escherichia coli, producing either NDM, IMP or KPC type carbapenemase were included in this study, and their proteomes were analysed in growth conditions with or without meropenem.
Project description:Chlamydia trachomatis serovariants are responsible for either Trachoma, the leading cause of infectious blindness or sexually transmitted disease, wherein the endocervix is the most frequently infected site in women. Disease caused by Chlamydia typically involves chronic inflammation and scarring. Recent work with a live-attenuated A2497 plasmid deficient vaccine strain (A2497-) demonstrated protection in nonhuman primates against trachoma and a lack of measurable ocular pathology in A2497- infected monkeys. We therefore performed host cell transcriptome analysis of Hela cells infected with A2497 plasmid-containing (A2497) and A2497- Chlamydia over time. Our results indicate that relative to wild type A2497, the A2497- variant illicits a transcriptome response indicative of lowered inflammation response a delayed apoptosis response, a reduction in immune cell recruitement cytokine expression and a reduction in genes involved in cell proliferation and or fibrosis-like activities. The data provided here suggests a model that may explain how plasmid deficient chlamydia may provide an immuno-protective response without the pathology normally seen with plasmid-containing bacteria.
Project description:Background: Treatment with single-agent decitabine (5aza-dC; DAC), a well-tolerated DNA hypomethylating drug, in a mouse model of pancreatic ductal adenocarcinoma (PDAC), KPC-Brca1, extended the survival of the animals and upregulated immune-related pathways. Here we extend these findings to combination therapy, using DAC followed by the immune checkpoint inhibitor anti-PD-1H in the original more widely utilized KPC (Pdx-Cre Kras/p53) model. Methods: We treated tumor-bearing KPC mice with DAC, and with anti-PD-1H, separately and in combination, and assessed tumor growth, mouse survival, immune cell infiltration of the tumors, and gene expression, compared to historical and mock-treated control mice. Results: Treatment with single-agent DAC led to increased Cd8+ tumor-infiltrating T cells (TILs), increased tumor necrosis, and slower tumor growth. RNA-seq analysis revealed increased expression of a group of myeloid-lineage markers, including Chi3l3 (Ym1), which proved to reflect recruitment or expansion of a unique population of Chi3l3/Arginase-1 double-positive “M2-polarized” tumor-infiltrating myeloid cells. Anti-PD-1H alone had only modest effects on tumor growth and number of Cd8+ TILs. However, PD-1H-expressing TILs were significantly increased by single agent DAC, and DAC treatment followed by anti-PD-1H produced the strongest increase in Cd8+ TILS, inhibition of tumor growth, and prolongation of survival. Conclusions: Treatment with DAC alone, and DAC plus anti-PD-1H, inhibits PDAC tumor growth in the KPC model and produces changes in tumor-infiltrating lymphoid and myeloid cell populations, with an additive therapeutic benefit from combining the two agents. Since the influx of M2-polarized macrophages induced by DAC is predicted to antagonize the anti-tumor effects, future work should investigate eliminating or reprogramming these cells.