The Role Of T Helper Cells-Specific Transcription Factors T-bet, GATA-3 In Asthmatic Airway Inflammation

Part OneExpression of Specific Transcription FactorsT-bet, GATA-3 in Asthmatic Airway InflammationStudy objectives: To investigate the expression of T helper cells-specifictranscription factors T-bet, GATA-3, and the changes of typical Th cytokinesin peripheral blood mononuclear cells (PBMC) from asthmatics.Patients and Methods: T-bet and GATA-3 mRNA level in peripheral bloodmononuclear cells (PBMCs) from 15 patients with asthma and 10 healthysubjects was determined by reverse transcription-polymerase chain reaction(RT-PCR). PBMCs were incubated with dexamethasone (Dex) and then theconcentration of Interferon (IFN)y and interleukin-4 in the supernatant wasdetermined. The number of CD4+CCR3+ and CD4+CCR5+ cells wascounted by Flow Cytometry (FCM), and sGaw was detected.Results: The level of T-bet mRNA (0.13±0.03 vs 0.18±0.04, P=0.006) inPBMCs of asthmatic patients was lower and the level of GATA-3 mRNA (0.43±0.07 vs 0.29±0.09, PO.001) was much higher compared with healthy subjects; meanwhile the level of T-bet (0.10±0.05, P=0.05) and GATA-3 (0.35±0.10, P=0.017) was decreased after pretreatment of Dex. The number of CD4+CCR3+ cells in asthmatics with Dex reduced much more than that without Dex (9.41±5.76 vs 5.24±3.70, P=0.028). The relation analysis showed that the ratio of T-bet to GATA-3 (T-bet/GATA-3) had positive relation with sGaw (r=0.407, P=0.01), and the level of T-bet and GATA-3 mRNA had positive relationship with IFN-y (r=0.663, PO.0001) and IL-4 (r=0.67, PO.0001) respectively.Conclusion: 1.Reduced expression of Thl-specific transcription factor T-bet or/and overexpression of Th2-specific transcription factor GATA-3 contribute to airway inflammation in asthmatics. 2. Downregulation of GATA-3 expression or restoration of balance in T-bet/GATA-3 perhaps are the important mechanism of Dex which inhibits the airway inflammation potently. 3. Imbanance of T-bet/GATA-3 expression not only directed development of Th and induced a selective alteration of patterns of cytokine expression, but the degree of airway inflammation.Part two The Role of Antisense-induced Local Blockade of T-betExpression in Pathogenesis of Airway Inflammation in RatsObjective: To explore the role of antisense-induced local blockade of T-bet expression in pathogenesis of airway inflammation in rats.Methods: 1 .T-bet expression was suppressed in local lung by delivery of an antisense oligonucleotide overlapping the translation start site of T-bet, whereas nonsense control oligonucleotides were delivered. 2. total white blood cell number and cellular composition in supernatants of bronchoalveolar lavage fluid (BALF) were detected, and IFN-Yn IL-4 and IL-5 levels in BALF were examined by ELISA. 3. T-bet mRNA level was detected by in situ hybridization, and GATA-3 expression was determined by immunohistochemistry.Results: 1. T-bet mRNA + cells in antisense oligonucleotide and OVA-sensitized rats were decreased compared with control rats (P<0.00\), while GATA-3 + cells were increased (PO.OOl). The relation analysis showed that the cells of T-bet mRNA + or GATA-3 + had positive relation with INF-y or IL-4 , IL-5, respectively. 2. total white blood cell number and eosinophils were increased evidently in antisense oligonucleotide and OVA-sensitized rats (PO.01). 3. The level of IFN-y in supernatant of BALF was decreased, and the level of IL-4, IL-5 was increased in antisense oligonucleotide and OVA-sensitized rats (PO.001). Conclusion: 1. Antisense-induced local blockade of T-bet expression in lung could lead to imbalance of T-bet/GATA-3, Thl/Th2. 2. A expression reduction of T-bet would induce a selective alteration of patterns of cytokine expression, which was seen analogously in asthmatic rats.