Project description:In the present study, genomic binding sites of glucocorticoid receptors (GR) were identified in vivo in the rat hippocampus applying chromatin immunoprecipitation followed by next-generation sequencing. We identified 2470 significant GR-binding sites (GBS) and were able to confirm GR binding to a random selection of these GBS covering a wide range of P values. Analysis of the genomic distribution of the significant GBS revealed a high prevalence of intragenic GBS. Gene ontology clusters involved in neuronal plasticity and other essential neuronal processes were overrepresented among the genes harboring a GBS or located in the vicinity of a GBS. Male adrenalectomized rats were challenged with increasing doses of the GR agonist corticosterone (CORT) ranging from 3 to 3000 μg/kg, resulting in clear differences in the GR-binding profile to individual GBS. Two groups of GBS could be distinguished: a low-CORT group that displayed GR binding across the full range of CORT concentrations, and a second high-CORT group that displayed significant GR binding only after administering the highest concentration of CORT. All validated GBS, in both the low-CORT and high-CORT groups, displayed mineralocorticoid receptor binding, which remained relatively constant from 30 μg/kg CORT upward. Motif analysis revealed that almost all GBS contained a glucocorticoid response element resembling the consensus motif in literature. In addition, motifs corresponding with new potential GR-interacting proteins were identified, such as zinc finger and BTB domain containing 3 (Zbtb3) and CUP (CG11181 gene product from transcript CG11181-RB), which may be involved in GR-dependent transactivation and transrepression, respectively. In conclusion, our results highlight the existence of 2 populations of GBS in the rat hippocampal genome. - See more at: http://press.endocrine.org/doi/10.1210/en.2012-2187?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed#sthash.LqK088DP.dpuf
Project description:Group B Streptococcus (GBS) is a pervasive perinatal pathogen, yet factors driving GBS dissemination in utero are poorly defined. Gestational diabetes mellitus (GDM), a complication marked by dysregulated immunity and maternal microbial dysbiosis, increases risk for GBS perinatal disease. We interrogated host-pathogen dynamics in a novel murine GDM model of GBS colonization and perinatal transmission. GDM mice had greater GBS in utero dissemination and subsequently worse neonatal outcomes. Dual-RNA sequencing revealed differential GBS adaptation to the GDM reproductive tract, including a putative glycosyltransferase (yfhO), and altered host responses. GDM disruption of immunity included reduced uterine natural killer cell activation, impaired recruitment to placentae, and altered vaginal cytokines. Lastly, we observed distinct vaginal microbial taxa associated with GDM status and GBS invasive disease status. Our translational model of GBS perinatal transmission in GDM hosts recapitulates several clinical aspects and enables discovery of host and bacterial drivers of GBS perinatal disease.
Project description:Background and aims: Guillain-Barré syndrome (GBS) is a rare disorder, with a global incidence ranging from 1 to 2 individuals per 100,000 people/year. Infections and vaccines have been implicated as causes triggering GBS. The aim of the study was to identify host genes involved in the pathogenesis of GBS when Zika (ZIKV) and Chikungunya viruses (CHIKV) were introduced in Brazil. Methods: A case-control study of GBS was performed when ZIKV and CHIKV were introduced into a naïve population. GBS was studied during both acute and postacute phases. RNA sequencing was conducted using whole blood. Results: GBS typically manifested a week after rash and fever; acute inflammatory demyelinating polyradiculoneuropathy was more frequent. None of the GBS cases had a poor outcome. Serological assays for ZIKV and CHIKV revealed high titers of immunoglobulin G for both viruses in 9 out of 11 subjects. Metatranscriptomic analyses unveiled an increased abundance of reads attributed to Pseudomonas tolaasii and Toxoplasma gondii in the acute phase. Analysis of differentially expressed host genes during the acute phase revealed altered expression of genes associated with axogenesis, synapse assembly, and presynapse organization. Moreover, genes upregulated during acute GBS were primarily related to inflammation and the inflammasome pathways, including AIM2, NLR family genes and LRR-protein genes, and IL-10. Interpretation: These findings suggest that inflammasome activation via AIM2 could play a role in tissue damage during GBS. Further investigation into the general activation of innate inflammatory responses is warranted to elucidate their potential contribution to the pathology of GBS.
Project description:The CiaRH and LiaFSR two-component regulatory systems in Streptococcus agalactiae (Group B Streptococcus, GBS) are essential mediators of the organism s response to biologically important sources of environmental stress, and positive regulators of GBS virulence. Transcriptional profiling of CiaR mutant GBS and LiaR mutant GBS reveals that LiaR is positively-regulated by CiaR, and the individual mutant transcriptomes share a number of commonly-regulated genes. To determine the GBS response to loss of both of these key regulatory systems, we constructed a GBS mutant strain with non-polar deletions in both ciaR and liaR, and performed transcriptional profiling using DNA microarray analysis, comparing wild-type GBS to CiaR/LiaR double mutant GBS under non-stressed conditions.
Project description:Diabetic wound infections have poor healing outcomes due to the presence of numerous pathogens in addition to an impaired immune response. Group B Streptococcus (GBS) is one of the most commonly isolated bacteria from diabetic wound infections, but virulence mechanisms GBS uses during these infections have not been investigated. Here, we developed a new murine model of GBS diabetic wound infection to determine how GBS establishes infection and persists in the wound environment. Using dual RNA sequencing, we demonstrate that GBS infection of diabetic wounds triggers an inflammatory response, leading to increased transcript levels of inflammatory cytokines and chemokines as well as markers of neutrophil degranulation such as myeloperoxidase, calprotectin, and elastase. We then confirm that diabetic wounds infected with GBS have significantly higher abundance of Il-1b, KC (CXCL1), myeloperoxidase, calprotectin and elastase in wound tissues than uninfected controls . When examining how GBS adapts to this hyper-inflammatory environment we find that GBS upregulates numerous virulence factors including the surface plasminogen-binding protein pbsP, the nuclease nucA, the cyl operon which is responsible for hemolysin production and pigmentation as well as numerous effectors of type VII secretion. In addition, we recovered multiple hyper-pigmented/hemolytic GBS colonies from the murine diabetic wound environment which encode mutations in the two-component system covRS. We then go on to demonstrate that a mutant in cylE, which is repressed by CovR, is attenuated in diabetic wound infection. Finally, we examine the most highly upregulated gene pbsP in diabetic wound infection and find that PbsP is necessary for diabetic wound infection via adherence to the skin and promotion of inflammation.