Minocycline blocks asthma-associated inflammation in part by interfering with the T cell receptor-nuclear factor κB-GATA-3-IL-4 axis without a prominent effect on poly(ADP-ribose) polymerase.

Minocycline protects against asthma independently of its antibiotic function and was recently reported as a potent poly(ADP-ribose) polymerase (PARP) inhibitor. In an animal model of asthma, a single administration of minocycline conferred excellent protection against ovalbumin-induced airway eosinophilia, mucus hypersecretion, and Th2 cytokine production (IL-4/IL-5/IL-12(p70)/IL-13/GM-CSF) and a partial protection against airway hyperresponsiveness. These effects correlated with pronounced reduction in lung and sera allergen-specific IgE. A reduction in poly(ADP-ribose) immunoreactivity in the lungs of minocycline-treated/ovalbumin-challenged mice correlated with decreased oxidative DNA damage. The effect of minocycline on PARP may be indirect, as the drug failed to efficiently block direct PARP activation in lungs of N-methyl-N'-nitro-N-nitroso-guanidine-treated mice or H(2)O(2)-treated cells. Minocycline blocked allergen-specific IgE production in B cells potentially by modulating T cell receptor (TCR)-linked IL-4 production at the mRNA level but not through a modulation of the IL-4-JAK-STAT-6 axis, IL-2 production, or NFAT1 activation. Restoration of IL-4, ex vivo, rescued IgE production by minocycline-treated/ovalbumin-stimulated B cells. IL-4 blockade correlated with a preferential inhibition of the NF-κB activation arm of TCR but not GSK3, Src, p38 MAPK, or ERK1/2. Interestingly, the drug promoted a slightly higher Src and ERK1/2 phosphorylation. Inhibition of NF-κB was linked to a complete blockade of TCR-stimulated GATA-3 expression, a pivotal transcription factor for IL-4 expression. Minocycline also reduced TNF-α-mediated NF-κB activation and expression of dependent genes. These results show a potentially broad effect of minocycline but that it may block IgE production in part by modulating TCR function, particularly by inhibiting the signaling pathway, leading to NF-κB activation, GATA-3 expression, and subsequent IL-4 production.

The decidual stromal cells-secreted CCL2 induces and maintains decidual leukocytes into Th2 bias in human early pregnancy.

The precise mechanism of characteristic Th2 predominance at maternal-fetal interface remains unresolved. In the present study, we investigated roles of the decidua-derived CCL2 in Th2 predominance at maternal-fetal interface. FCM shows that 55% CD56(+)CD16(-)CD3(-) decidual NK, 52% CD4(+) T cells and 75% CD14(+) monocytes express CCR2. Recombinant human CCL2 (rhCCL2) and the decidual stromal cells (DSCs)-derived supernatant can enhance proliferation and inhibit apoptosis of these decidual leukocytes (DLCs), and promote Th2 cytokines production, IL-4 and IL-10, with an increase in GATA-3 transcription. They also inhibit the secretion of Th1 cytokines, TNF-α and IFN-γ, with a decrease in T-bet transcription It is concluded that the secreted CCL2 by decidual stromal cells increases GATA-3 transcription and decreases T-bet transcription in the decidual leukocytes, which contributes to Th2 polarization at maternal-fetal interface. Furthermore, the Th2 cytokines, IL-4 and IL-10, rather than Th1 cytokines, was shown to increase CCL2 secretion of DSC.

Activation of the cholinergic anti-inflammatory system by nicotine attenuates neuroinflammation via suppression of Th1 and Th17 responses.

The alpha7 nicotinic acetylcholine receptor (nAChR) was recently described as an anti-inflammatory target in both macrophages and T cells. Its expression by immune cells may explain the epidemiological data claiming a negative link between cigarette smoking and several inflammatory diseases. In this study, we determined the immunological effects of alpha7 nAChR activation by nicotine. Our results indicate that the alpha7 nAChR is expressed on the surface of CD4(+) T cells and that this expression is up-regulated upon immune activation. Nicotine reduced T cell proliferation in response to an encephalitogenic Ag, as well as the production of Th1 (TNF-alpha and IFN-gamma) and Th17 cytokines (IL-17, IL-17F, IL-21, and IL-22). IL-4 production was increased in the same setting. Attenuation of the Th1 and Th17 lineages was accompanied by reduced T-bet (50%) and increased GATA-3 (350%) expression. Overall, nicotine induced a shift to the Th2 lineage. However, alpha7(-/-)-derived T cells were unaffected by nicotine. Furthermore, nicotine reduced NF-kappaB-mediated transcription as measured by IL-2 and IkappaB transcription. In vivo, administration of nicotine (2 mg/kg s.c.) suppressed the severity of CD4(+) T cell-mediated disease experimental autoimmune encephalomyelitis. alpha7(-/-) mice were refractory to nicotine treatment, although disease severity in those animals was reduced, due to impairment in Ag presentation. Accordingly, CD4(+) and CD11b(+) cells infiltration into the CNS, demyelination, and axonal loss were reduced. Our data implicate a role for the alpha7 nAChR in immune modulation and suggest that alpha7 nAChR agonists may be effective in the treatment of inflammatory disorders.

Transcription factor GATA-3 in Atlantic salmon (Salmo salar): molecular characterization, promoter activity and expression analysis.

GATA-3 is a T cell-specific transcription factor and is essential for the development of the T cell lineage and differentiation of T helper type 2 cells. We have identified and characterized the full-length Atlantic salmon GATA-3 cDNA (3074bp), having two zinc finger domains which are fully conserved within teleosts and higher vertebrates. RT-PCR analysis revealed that the Atlantic salmon GATA-3 (AsGATA-3) is strongly expressed in gills, thymus, and brain. Moreover, the involvement of GATA-3 in Atlantic salmon immune response was demonstrated by investigating the early time dependent expression profile of GATA-3 in spleen and head kidney following intraperitoneal injection of live Aeromonas salmonicida, LPS, and beta-glucan. Furthermore, we have determined 1.9kb of upstream promoter sequence and found a number of sequence motifs which match those of known transcription factor binding sites and the AsGATA-3 promoter is a TATA-less promoter. Activities of presumptive regulatory regions of this gene were assessed by transfecting different 5' deletion constructs and the result showed the basal promoter and positive transcriptional regulator activity of AsGATA-3 gene is determined by sequences located between +58 and -199bp upstream of the transcriptional start site (TSS). This study provides further insights into the transcriptional regulation of AsGATA-3.