IL-12-induced T-bet expression and IFNγ release in lymphocytes from asthmatics—Role of MAPkinases ERK-1/-2, p38MAPK and effect of dexamethasone

Abstract

The transcription factor T-box-expressed-in-T-cells (T-bet) is required for T(H)1 lymphocyte differentiation, regulates the IL-12-induced expression of the T(H)1-specific cytokine IFNgamma and may be dysregulated in asthmatics. The modulatory role of extracellular signal-regulated kinase (ERK)-1/-2, p38mitogen-activated protein kinase (MAPK) and dexamethasone on IL-12 induced T-bet and IFNgamma expression was assessed in peripheral blood lymphocytes of 10 atopic asthmatics and 10 nonatopic normals. IFNgamma production was dependent on phosphorylation of ERK-1/-2 and p38MAPK, as examined by PD098059, an inhibitor of the upstream activator of MAPKkinase (MKK-1), and SB203580, an inhibitor of p38MAPK. The inhibitory effect of PD098059 on IFNgamma release was decreased in asthmatic T-cells compared with normals. The IL-12-induced T-bet expression and the inhibitory effect of SB203580 were increased in asthmatic T-cells compared with normals. Dexamethasone blocked the IL-12-induced T-bet expression in asthmatic T-cells completely and decreased IL-12-induced IFNgamma release by approximately 50%, which occurred to the same extent in asthmatic and normal T-cells. In conclusion, (1) p38MAPK-pathway rather than ERK-pathway may play a more basic role in the regulation of the increased T-bet expression in asthma, and (2) ERK- and p38MAPK-activation modulate IFNgamma expression independently of T-bet and this regulatory role of ERK-1/-2 on IFNgamma release is impaired in asthma. The therapeutic benefit of dexamethasone on T-bet and IFNgamma production seems to be critical.

Histamine receptor H1 is required for TCR-mediated p38 MAPK activation and optimal IFN-γ production in mice

“…Although the precise mechanism by which p38 MAPK regulates IFN-γ production in CD4 + T cells remains unclear, recent studies have suggested that the activation of the this MAPK pathway is required for T-bet expression (32,33), and T-bet regulates IFN-γ production (34). We therefore examined T-bet expression by Western blot analysis during activation of WT and H1RKO CD4 + T cells.…”

Heterogeneity of transcription factor expression and regulation in human airway epithelial and smooth muscle cells

“…The role of transcription factors in immune cells has revealed a number of important pathways that initiate or maintain inflammation (1,3,11,12,16,24). Here we show that these two resident structural cells, airway epithelial and smooth muscle, also undergo changes in expression of transcription factors in an inflammatory environment.…”

“…In asthma, two stromal cell types play significant roles in the syndrome: the airway epithelial cell and the airway smooth muscle cell (5, 9). Although some information is known about the regulation and action of selected transcription factors of immune cells of the lung and peripheral circulation (1,11,12,24), there is a paucity of data on the expression of transcription factors in airway epithelial and smooth muscle cells. Furthermore, there are no studies that examine a large complement of transcription factors expressed in these cells and their modulation by inflammatory stimuli or ␤-agonists, the most common treatment for asthma.…”

Effect of lipoteichoic acid on IL-2 and IL-5 release from T lymphocytes in asthma and COPD

“…PBMCs were isolated from the peripheral blood of donors as described in Koch et al [33]: Peripheral venous blood obtained by venipuncture was added to anticoagulant-citrate-dextrose solution (ACD: 277 mM D-(+)-glucose; trisbase sodium citrate) as anticoagulant at a final concentration of 10% (v/v). HAES (6-hydroxyethyl starch) was added in a 1:4 ratio.…”

“…For Ficoll gradient sedimentation cells in HBSS were layered over a Ficoll-paque and centrifuged for 30 minutes at 360 g at 18°C. PBMCs in the upper phase were washed three times with HBSS and resuspended in RPMI 1640 culture medium (Sigma, Munich Germany) containing 10% heat-inactivated FCS (fetal calf serum), 2 mM L-glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin as previously described [18,33]. PBMCs were cultured in RPMI 1640 medium or subjected to immunomagnetic depletion Kits in order to purify monocytes or T cells (see below).…”