Reduced Expression of Nuclear Cyclic Adenosine 5′-Monophospate Response Element-Binding Proteins and IFN-γ Promoter Function in Disease Due to an Intracellular Pathogen

Abstract

Mycobacterium tuberculosis-induced IFN-γ protein and mRNA expression have been shown to be reduced in tuberculosis patients, compared with healthy tuberculin reactors. To determine whether this decrease was associated with reduced activity of the IFN-γ promoter, we first studied binding of nuclear proteins to the radiolabeled proximal IFN-γ promoter (−71 to −40 bp), using EMSAs with nuclear extracts of freshly isolated peripheral blood T cells. Nuclear extracts of T cells from most tuberculosis patients showed markedly reduced expression of proteins that bind to the proximal IFN-γ promoter, compared with findings in nuclear extracts of T cells from healthy tuberculin reactors. These DNA-binding complexes contained CREB proteins, based on competitive EMSAs, supershift assays, and Western blotting with an anti-CREB Ab. Transient transfection of PBLs with a luciferase reporter construct under the control of the IFN-γ promoter revealed reduced IFN-γ promoter activity in tuberculosis patients. Transient transfection of Jurkat cells with a dominant-negative CREB repressor plasmid reduced IFN-γ promoter activity. These data suggest that reduced expression of CREB nuclear proteins in tuberculosis patients results in decreased IFN-γ promoter activity and reduced IFN-γ production.

CD40 Ligand Trimer Enhances the Response of CD8+ T Cells to Mycobacterium tuberculosis

“…Some investigators found that CREB inhibited IFN-␥ transcription (31,55). In contrast, others found that CREB-enhanced IFN-␥ transcription (28,29), and reduced CREB expression, paralleled decreased IFN-␥ promoter activity in tuberculosis patients (29). In view of these findings, we determined whether CD40LT enhanced IFN-␥ production by M. tuberculosis-reactive CD8 ϩ T cells through the transcription factors CREB and AP-1.…”

“…To investigate the mechanism for this effect, we studied transcription factors that bind the IFN-␥ promoter and enhance IFN-␥ mRNA expression in T cells. One of these transcription factors is CREB (28), and reduced CREB expression is associated with decreased IFN-␥ production in human tuberculosis (29). Phosphorylation of CREB enhances its capacity to up-regulate gene transcription (30) and we used Western blotting with a mAb specific for phosphorylated CREB to show that stimulation of CD8 ϩ T cells from three healthy donors with PMA and ionomycin enhanced phosphorylation of CREB within 15 min (Fig.…”

β-Caryophyllene Inhibits Dextran Sulfate Sodium-Induced Colitis in Mice through CB2 Receptor Activation and PPARγ Pathway

“…35 Genes whose transcription is regulated by CREB include those encoding the T helper type 1 (T H 1) cytokines. 61,62 The T H 1 cytokines encompass the cytokine profile of acute murine DSSinduced colitis (INF-␥, TNF-␣, and IL-1␤). 63 In T H 1 cells, the recruitment of phospho-CREB is significantly higher than in T H 2 cells.…”

Association of interferon gamma and interleukin 10 genes with tuberculosis in Hong Kong Chinese

“…13,14 This may be ascribed to the þ 874 A/A genotype, 14 and also the reduced expression of nuclear cyclic adenosine 5 0 -monophosphate response element-binding protein and reduced IFN-g promoter activity in TB patients. 15 Moreover, IFN-g production from PBMCs is depressed in TB patients with A/A genotype when compared with A/T or T/T genotype at the time of diagnosis and after completion of treatment. 14 This suggests that A/A genotype may be related to TB severity or reactivation.…”