Early immune response and regulation of IL-2 receptor subunits
ABSTRACT Affymetrix oligonucleotide arrays were used to monitor expression of 8796 genes and probe sets in activated T-cells; analysis revealed that 217 genes were significantly upregulated within 4 h. Induced genes included transcription factors, cytokines and their receptor genes. Analysis by semi-quantitative RT-PCR confirmed the significant induction of IL-2, IL-2R(gamma) and IL-2R(alpha). Forty-eight of the 217 induced genes are known to or predicted to be regulated by a CRE promoter/enhancer. We found that T-cell activation caused a significant increase in CREB phosphorylation furthermore, inhibition of the PKC pathway by GF109203 reduced CREB activation by 50% and inhibition of the PKA pathway caused a total block of CREB phosphorylation and significantly reduced IFN(gamma), IL-2 and IL-2R(alpha) gene expression by approximately 40% (p<0.001). PKC(theta) plays a major role in T-cell activation: inhibition of PKC significantly reduced the expression of IFN(gamma), IL-2 and IL-2R(alpha). Since PKC blocked activation of CREB, we studied potential cross-talk between the PKC and the PKA/MAPK pathways, PMA-stimulated Jurkat cells were studied with specific signal pathway inhibitors. Extracellular signal-regulated kinase-2 (ERK2) pathway was found to be significantly activated greater than seven-fold within 30 min; however, there was little activation of ERK-1 and no activation of JNK or p38 MAPK. Inhibition of the PKA pathway, but not the PKC pathway, resulted in inhibition of ERK1/2 activation at all time points, inhibition of MEK1 and 2 significantly blocked expression of IL-2 and IL-2R(alpha). Gene expression of IL-2R(alpha) and IFN(gamma) was dependent on PKA in S49 wt cells but not in kin- mutants. Using gel shift analysis, we found that forskolin activation of T-cells resulted in activation of AP1 sites; this increase in nuclear extract AP1 was significantly blocked by MEK1 inhibitor U0126. Taken together, these results suggest that the PKA in addition to PKC and MAPK pathways plays a role in early T-cell activation and induction of IL-2, IL-2R(alpha) and IFN(gamma) gene expression.
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ABSTRACT: Inflammatory bowel disease is deregulation of the mucosal immune system, changes in the composition of gut micro flora and deranged epithelial barrier function.Crohn's disease is associated with a Th 1 -type immune response with production of TNF-α, interferon-gamma (IFN-γ) and IL-12, whereas ulcerative colitis is associated with Th 2 response with abundant IL-5 and IL-10. In a mouse model, Th1 cytokine responses resulted in the acute transmural and focal lesions; whereas Th2 cytokine responses resulted in diffuse atrophic changes in crypts and the mucosal layer. Animal models of inflammatory bowel disease (1) Inducible colitis models: Exogenous colitogenic substance that disrupts the mucosal integrity(2) Gene knockout (KO) models: Abnormalities in production of regulatory cytokines (3) Transgenic models: Mice deficient in a transcription factor (4)Spontaneous colitis models: immunodeficient mouse strains created via gene targeting in embryonic stem cells. (5)Adoptive transfer models: Selective transfer of certain cell types to immunocompromised host animals affected by many immunological and genetic factors.
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ABSTRACT: Spaceflight is associated with deregulation in the immune system. Head-down bed rest (HDBR) at -6° is believed to be the most practical model for examining multi-system responses to microgravity in humans during spaceflight. In the present study, a 45-day HDBR was performed to investigate the alterations in human immune cell distributions and their functions in response to various stimuli. The effect of countermeasure, Rhodiola rosea (RR) treatment, was also examined. A significant decrease of interferon-γ (IFN-γ) and interleukin-17 (IL-17) productions by activated T cells, increase of IL-1β and IL-18 by activated B and myeloid cells were observed during HDBR. The upregulation of serum cortisol was correlated with the changes of IL-1 family cytokines. In addition, a significant increase of memory T and B cell and regulatory T cells (Treg) were also detected. The uptake of RR further decreased IFN-γ level and slowed down the upregulation of IL-1 family cytokines. These data suggest that for prolonged HDBR and spaceflight, the decreased protective T cell immunity and enhanced proinflammatory cytokines should be closely monitored. The treatment with RR may play an important role in suppressing proinflammatory cytokines but not in boosting protective T cell immunity.PLoS ONE 10/2013; 8(10):e77401. DOI:10.1371/journal.pone.0077401 · 3.53 Impact Factor
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ABSTRACT: Regeneration of the immune system after hematopoietic stem cell transplantation (HSCT) is a slow process. We attempted to identify problems in the recovery of the immune system by examining expressions of early event cell cycle proteins Myc, Jun, and Fos, as well as DNA binding of Myc, activating protein 1 (AP-1), and CD4 cell activation values, in phytohemagglutinin-activated T lymphocytes taken from patients after HSCT. HSCT patients showed lower protein expression levels of Myc and Jun, as well as Myc and AP-1 DNA-binding levels, as compared to healthy controls. C-Jun was lower in long-term survivors of HSCT than short-term survivors. Adenosine triphosphate (ATP) values in CD4 cells were also lower in HSCT patients than healthy controls, but showed a time-dependent increase post-transplant. Non-surviving patients showed lower levels of both Fos protein and ATP as compared to surviving patients and a negative correlation between Fos values and lymphocyte percentage that was not present in surviving patients. There was a strong positive correlation between Fos values and lymphocyte percentage and between AP-1 values and white blood count, in patients without graft-versus-host disease (GVHD), that did not exist in patients who suffered from GVHD. Patients 2 years post-HSCT showed a positive correlation between AP-1 and Myc DNA-binding protein values, similar to those values found in healthy controls. Our study identified significant factors that account for the delay in immune reconstitution after transplant; this knowledge may improve the management of post-HSCT patients.Clinical and Experimental Medicine 08/2014; DOI:10.1007/s10238-014-0285-6 · 2.82 Impact Factor