Project description:Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for survival. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. Previous work has identified a small RNA, HrrF, that is Fur-regulated in NTHi 86-028NPrpsL.To understand the contribution made by HrrF to gene regulation in NTHi, hrrF was deleted in the NTHi strain 86-028NPrpsL∆fur. Using RNA-Seq, we identified protein-encoding genes whose expression was repressed or activated by HrrF.
Project description:Nontypeable Haemophilus influenzae (NTHi) is a pathobiont which chronically colonises the airway of individuals with chronic respiratory disease. It is unclear how NTHi persists in the airway, however accumulating evidence suggests that NTHi can invade and persist within macrophages. To better understand the mechanisms of NTHi persistence within macrophages, this work developed an in vitro model of NTHi intracellular persistence using human monocyte-derived macrophages (MDM). Dual RNA Sequencing was used to assess MDM and NTHi transcriptomic regulation occurring simultaneously during NTHi persistence. This work demonstrates that NTHi can invade and persist within human macrophages. Macrophages activate innate immune responses, whereas NTHi persistence was facilitated by transcriptomic adaptations in bacterial metabolic, stress response and ribosome pathways. This research provides transcriptomic insights into NTHi-macrophage interactions, enhances our understanding of how NTHi can utilise host immune cells to chronically colonise the airway and identifies potential bacterial gene pathways that may be attractive therapeutic targets
Project description:Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for survival. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. Previous work has identified a small RNA, HrrF, that is Fur-regulated in NTHi 86-028NPrpsL.To understand the contribution made by HrrF to gene regulation in NTHi, hrrF was deleted in the NTHi strain 86-028NPrpsLM-bM-^HM-^Ffur. Using RNA-Seq, we identified protein-encoding genes whose expression was repressed or activated by HrrF. These data comprise transcriptional anaylses of an rpsL mutant of 86-028NP, an isogenic fur mutant of 86-028NPrpsL, an isogenic fur mutant of 86-028NPrpsL also containing a full deletion of hrrF, and an isogenic fur mutant of 86-028NPrpsL also containing a deletion of only the 3' portion of hrrF. All strains were grown in defined medium containing 10 M-BM-5g/ml human hemoglobin to mid-log phase. Cells were then harvested and RNA extracted. A total of three biological replicates were generated for these analyses. Analysis of transcriptomes using the Illumina HiSeq 2000 of four strains of nontypeable Haemophilus influenzae which include NTHi 86-028NPrpsL, NTHi 86-028NPrpsLM-bM-^HM-^Ffur, NTHi 86-028NPrpsLM-bM-^HM-^FfurM-bM-^HM-^FhrrF, and NTHi 86-028NPrpsLM-bM-^HM-^FfurM-bM-^HM-^FhrrF3' strains. For each strain three biological replicates were analyzed.