BackgroundWe have previously shown that 8 weeks’ treatment with phenylbutyrate (PBA) (500mgx2/day) with or without vitamin D3 (vitD3) (5000 IU/day) as host-directed therapy (HDT) accelerated clinical recovery, sputum culture conversion and increased expression of cathelicidin LL-37 by immune cells in a randomized, placebo-controlled trial in adults with pulmonary tuberculosis (TB). In this study we further aimed to examine whether HDT with PBA and vitD3 promoted clinically beneficial immunomodulation to improve treatment outcomes in TB patients.MethodsCytokine concentration was measured in supernatants of peripheral blood mononuclear cells (PBMC) from patients (n = 31/group). Endoplasmic reticulum stress-related genes (GADD34 and XBP1spl) and human beta-defensin-1 (HBD1) gene expression were studied in monocyte-derived-macrophages (MDM) (n = 18/group) from PBMC of patients. Autophagy in MDM (n = 6/group) was evaluated using LC3 expression by confocal microscopy.ResultsA significant decline in the concentration of cytokines/chemokines was noted from week 0 to 8 in the PBA-group [TNF-α (β = − 0.34, 95% CI = − 0.68, − 0.003; p = 0.04), CCL11 (β = − 0.19, 95% CI = − 0.36, − 0.03; p = 0.02) and CCL5 (β = − 0.08, 95% CI = − 0.16, 0.002; p = 0.05)] and vitD3-group [(CCL11 (β = − 0.17, 95% CI = − 0.34, − 0.001; p = 0.04), CXCL10 (β = − 0.38, 95% CI = − 0.77, 0.003; p = 0.05) and PDGF-β (β = − 0.16, 95% CI = − 0.31, 0.002; p = 0.05)] compared to placebo. Both PBA- and vitD3-groups showed a decline in XBP1spl mRNA on week 8 (p < 0.03). All treatment groups demonstrated increased LC3 expression in MDM compared to placebo over time (p < 0.037).ConclusionThe use of PBA and vitD3 as adjunct therapy to standard TB treatment promoted favorable immunomodulation to improve treatment outcomes.Trials registrationThis trial was retrospectively registered in clinicaltrials.gov, under identifier NCT01580007.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3203-9) contains supplementary material, which is available to authorized users.
Objective
The objective of this study is to structurally characterize the interaction between the Pseudomonas aeruginosa PA01extra‐cytoplasmic‐function (ECF) sigma factor, FpvI, and the sigma regulator, FpvR.
Hypothesis
The extra‐cytoplasmic‐function (ECF) sigma factor, FpvI, interacts with high affinity with the N‐terminal anti‐sigma domain of FpvR. It can be purified to homogeneity and used for structural studies by X‐ray crystallography.
Summary
Transcription of the pyoverdine transport system of Pseudomonas aeruginosa PA01 is mediated by Cell Surface Signaling (CSS). This process involves binding of the siderophore ferric‐pyoverdine to the outer membrane transporter FpvA. This event triggers the regulated intramembrane proteolysis of the sigma regulator, FpvR. Release of the FpvR anti‐sigma domain (ASD) in complex with the extra‐cytoplasmic‐function (ECF) sigma factor FpvI, directs RNA polymerase to the promoter of FpvA to initiate the transcription. The molecular details of the interaction between FpvR ASD and FpvI are not known. We are using a dual expression plasmid to produce the FpvR ASD and a his‐tagged construct of FpvI. Immobilized metal affinity chromatography (IMAC) followed by size exclusion chromatography is used to purify the complex. We have characterized the complex by Circular dichroism (CD) to show it is well folded. This protein is being further characterized by sparse matrix crystal screening and Small‐angle X‐ray scattering (SAXS).
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