Project description:The anaerobic Gram-positive bacterium Propionibacterium acnes is a human skin commensal, but is occasionally associated with inflammatory diseases. Recent work has indicated that evolutionary distinct lineages of P. acnes play etiologic roles in disease while others are associated with health. To shed light on the molecular basis for differential strain properties, we carried out genomic and transcriptomic analysis of distinct P. acnes strains. We sequenced the genome of the P. acnes strain 266, a type I-1a sequence type (ST) 18 strain. Comparative genome analysis of strain 266 and four other P. acnes strains revealed that overall genome plasticity is relatively low; however, a number of island-like genomic regions, encoding a variety of putative virulence-associated and fitness traits, differ between phylotypes. Comparative transcriptome analysis revealed that 225 genes of strain KPA171202 (type I-2, ST34) were differentially transcribed in strain 266 during exponential growth. 47% of these genes belong to the strain-specific gene content of strain KPA171202, indicating that strain-specific functions are utilized. Next, we studied differential expression during exponential and stationary growth phases. Genes encoding components of the energy-conserving respiratory chain as well as secreted and virulence-associated factors were transcribed during the exponential phase, while the stationary growth phase was characterized by up-regulation of genes involved in the stress response and amino acid metabolism. Taken together, our data highlight the genomic basis for strain diversity and identify, for the first time, the transcribed part of the genome, underling the important role active growth plays in the inflammatory activity of P. acnes. We argue that the disease-causing potential of different P. acnes strains is not only determined by variable genome content but also, and to a greater degree, by variable transcriptomes. Microarray experiments were performed as dual-color hybridizations. In order to compensate specific effects of the dyes and to ensure statistically relevant data analysis, a color-swap dye-reversal was performed. Two different labeling methods were applied. RNA labeling was performed with the two color Quick Amp Labeling Kit (Agilent Technologies) using FullSpectrum MultiStart Primer for T7 IVT RNA Amplification (BioCat GmbH, Heidelberg, Germany) as random T7 labeling. Alternatively, the total RNA samples were amplified with the TransPlex Whole Transcriptome Amplification Kit (Sigma-Aldrich, Munich, Germany) and labeled with BioPrime Plus Array CGH Indirect Genomic Labeling System (Invitrogen, Karlsruhe, Germany) as WTA BioPrime indirect. Both methods were compared and combined for final data analysis.

Project description:The composition of the prostate microbiome may influence the fate of the cells that may be relevant to prostate morbidity. Several independent studies have reported the presence of the bacterium Propionibacterium acnes in diseased human prostate tissue. It is unclear if the bacterium is an infectious agent, part of a normal prostate microbiota or if it is derived from the skin and accidentally introduced, for instance during a prostate biopsy. Previous research with prostate cell culture and animal models has revealed the capability of P. acnes to establish a low-grade chronic inflammation. However, the fate of primary prostate cells exposed to P. acnes has not been investigated in molecular detail. Here, we investigated the impact of P. acnes on human primary prostate epithelial cells (PrEC). An initial analysis of the host cell response by microarray technology confirmed the inflammation-inducing capability of P. acnes but also showed the deregulation of genes involved in cell cycle, and more specifically in kinetochore and centromere functionality. In particular, we could show and confirm by qPCR that only viable P. acnes downregulated a master regulator of cell cycle progression, FOXM1, as well as its target genes. It was further shown by flow cytometry that P. acnes was indeed able to alter the cell cycle by increasing the number of PrEC cells in S-phase. In search for a molecular explanation we tested the hypothesis that a P.acnes produced berninamycin A-like thiopeptide, that is a structurally closely related to the known FOXM1 inhibitor siomycin A, is responsible for the effect on FOXM1 and the cell cycle. A knock-out mutant in P. acnes was created that lacked the gene encoding the berninamycin A peptide precursor; this mutant was unable to downregulate FOXM1, suggesting that a berninamycin A-like thiopeptide induces cell cycle alterations in PrEC cells. Interestingly, the gene cluster encoding this thiopeptide is restricted to a subtype of P. acnes that is relatively rare on human skin, but more often found in prostate tissue.

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Propionibacterium acnes HKGB1

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