Project description:Isogenic deletion and truncation of specific genes encoding RNases in Brucella abortus were analyzed for changes in gene expression. The main goal of this work is to determine the mRNAs that exhibit dysregulation when small regulatory RNAs (i.e., Bsr8) or RNases (i.e., RNaseE and RNaseJ) are invactivated in Brucella abortus. Small regulatory RNAs often control gene expression by binding directly to mRNAs to block translation or induce their degradation, and RNA from a deletion of one sRNA gene, bsr8, was analyzed to uncover the mRNAs that may be controlled by BsrB. RNases are enzymes that cleave RNAs during processing, turnover, and regulatory events, and RNaseE and RNaseJ appear to be important for B. abortus virulence. Therefore, to determine the mRNAs potentially targetd by these RNases, RNA from a strain harboring a RNaseE truncation and a strain carrying a deletion of rnaseJ were analyzed. In the end, the objective of this study was to gain insight into the regulatory patterns of specific B. abortus sRNAs and RNases.
Project description:Gene expression analysis of wild-type and STING knock-out mouse bone marrow-derived macrophages (mBMDM) infected with Brucella abortus or transfected with Brucella abortus DNA. Genes whose expression are affected by Brucella abortus in a STING-dependent manner will be identified and signaling pathways regulated by STING will be elucidated.
Project description:Brucellosis is an important zoonotic disease that causes great economic losses. Vaccine immunisation is the main strategy for the prevention and control of Brucellosis. Although live attenuated vaccines play important roles in the prevention of this disease, they also have several limitations, such as residual virulence and difficulty in the differentiation of immunisation and infection. We developed and evaluated a new bacteria ghost vaccine of Brucella abortus A19 by a new double inactivation method. The results showed that the bacterial ghost vaccine of Brucella represents a more safe and efficient vaccine for Brucellosis. We further characterised the antigenic components and signatures of the vaccine candidate A19BG. Here, we utilised a mass spectrometry-based label-free relative quantitative proteomics approach to investigate the global proteomics changes in A19BGs compared to its parental A19. The proteomic analysis identified 2014 proteins, 1116 of which were differentially expressed compared with those in A19. The common immunological proteins of OMPs (Bcsp31, Omp25, Omp10, Omp19, Omp28, and Omp2a), HSPs (DnaK, GroS, and GroL), and SodC were enriched in the proteome of A19BG. By protein micro array- based antibody profiling, significant differences were observed between A19BG and A19, and a number of signature immunogenic proteins were identified. Two of these proteins, BMEII0032 and BMEI0892, were confirmed to be differential diagnostic antigens for the A19BG vaccine candidate. In conclusion, using comparative proteomics and antibody profiling, protein components and signature antigens were identified for the ghost vaccine candidate A19BG, which are valuable for further developing the vaccine and its monitoring assays.
Project description:We focused on whether transposon mutagenesis in Brucella abortus could induce difference in the trascriptional responses of RAW 264.7 cell infection model compared to the wild strain infected RAW 264.7 cells. The function of genes in Brucella abortus was analyzed through the identified differences in gene expression between RAW 264.7 cell infected with wild and mutant strains.
Project description:MucR is one of the few transcriptional regulatory proteins that has been linked to Brucella pathogenesis. We used custom-made Affymetrix B. abortus strain 2308 derived GeneChips to copare the gene expression properties of wild type and isogenic mucR mutant cells.
Project description:We describe the isolation of sufficient Brucella abortus RNA from primary host cell environment using modified reported methods for RNA-seq analysis, and simultaneously characterize the transcriptional profiles of intracellular B. abortus and bone marrow-derived macrophages (BMM) from BALB/c mice at 24 h (replicative phase) post-infection.
Project description:Brucellosis is still a widespread zoonotic disease. Very little is known about the interaction between B. abortus and trophoblastic cells, which is essential for better understanding the pathogenesis of the Brucella-induced placentitis and abortion, a key event for transmission of the disease. The goal of this study was to evaluate the profile of gene expression by bovine trophoblastic cells during infection with B abortus. Explants of chorioallantoic membranes were inoculated with B. abortus strain 2308. Microarray analysis was performed at 4 h after infection, and expression of cytokines and chemokines by trophoblastic cells was assessed by real time RT-PCR at 6 and 12 h after inoculation. In addition, cytokine and chemokine expression was evaluated in placentomes from experimentally infected cows. Expression of pro-inflammatory genes by trophoblastic cells was suppressed at 4 h after inoculation, whereas a significant up-regulation of CXC chemokines, namely CXCL6 (GCP-2) and CXCL8 (IL-8), was observed at 12, but not at 6 h after inoculation. Placentomes of experimentally infected cows had a similar profile of chemokine expression, with upregulation of CXCL6 and CXCL8. Our data indicate that B. abortus modulates the innate immune response by trophoblastic cells, suppressing expression of pro-inflammatory mediators during the early stages of infection that is followed by a delayed and mild expression of pro-inflammatory chemokines, which is similar to the profile of chemokine expression in the placentomes of experimentally infected cows. This trophoblastic response is likely to contribute to the pathogenesis of B. abortus-induced placentitis. Keywords: trophoblast response to Brucella