Suppression Strategy. STAT1 Explore

Asthma is a chronic airway disease which is characterised by persistant airway inflammation and airway hyper-responsiveness (AMR) even in chronic phase, during which no apparent allergen contact happened. The mechanism of this phenomena is waiting to be explored. Recently, Holtzman thought that Signal Transduction and Activator of Transcription 1 (STAT1) may play a critical role in chronic asthma phenotype, in which the exclusively up-regulated STAT1 among a bunch of other transcription factors, for example, Nuclear factor- k B and Activator of Protein-1 made it a candidate responsible for the chronic pathological changes. We plan to further explore the chronic asthmatic phenotype and STAT1 expression in animal models and than evaluate the effectiveness and specificity of a potent STAT1 inhibitor, fludarabine in supressing STAT1 expression and inflammtion and finally. Fludarabine exhibited anti-inflammatory mechanisms other than STAT1 inhibition, so we further constructed a dominant negative mutant of STAT1 in order to supress STAT1 in a more specific manner.Part OneStat1 Expression in Chronic Asthmatic Animals Objectives: To investigate the pulmonary STAT1 expression andpathological changes in chronic asthmatic animals. Methods: 30 C57BL/6 mice were divided into 3 groups: A, controls; B, chronic asthma models prepared by prolonged inhalation of ovalbumin and C, established chronic asthmatic models were avoided allergen contact for one month. Pulmonary inflammation, fibrosis and the expression of STAT1 were evaluated. Results: Submucosal collgen accumulation in group C were heavier than in group A and B (P<0.05) while pulmonary inflammation in group C is less severe than in group B (P<0.05). STAT1 expression in group C is higher than in other two groups (P<0.05). Conclusion: Airway remodeling in chronic asthma subjects is not dependent upon allergen contact and submucosal inflammation. STAT1 up-regulation is one of the characteristics during chronic phase of asthma.Part Two Effects of Fludarabine in Pulmonary InflammationCharacterised by STAT1 up-regulationObjecitves: To evaluate the effects of fludarabine, one of the potent STAT1 inhibitors in the process of pulmonary inflammation which characterised by STAT1 up-regulatoin. Methods: Lipopolysaccharide was used to prepare the model of acute pulmonary inflammation in mice, the effects of fludarabine upon the inflammation and STAT1expression were evaluated. Results: LPS caused severe pulmonary inflammation in mice, accompanied by STAT1 up-regulation. Fludarabine inhalation alleviated lung inflammtion and down-regulated STAT1 expression.Conclusions: Fludarabine inhalation could significantly inhibit STAT1 expression and improve inflammation during LPS induced pulmonary inflammation.Part Three Effects of Fludarabine in Pulmonary InflammationCharacterised by STAT1 down-regulationObjectives: To evaluate the effects of fludarabine, one of the potent STAT1 inhibitors, in the process of pulmonary inflammation which characterised by STAT1 down-regulatoin. Methods: 21 mice were divided into 3 groups, group A, controls; group B, Sendai virus infected subjects; group C, virus infected subjects treated by fludarabine. The effects of fludarabine upon the inflammation and STAT1 expression were evaluated. Resultes: Sendai virus infection caused severe pulmonary inflammation and STAT1 down-regulation (P<0.05). Fludarabine treatment had beneficial effects upon lung inflammation (PO.05) while did not affect the down-regulated STAT1 levels. Conclusions: In Sendai viral pneumonia which is characterised by STAT1 down-regulation, the effects of fludarabine showed it hadanti-inflammatory mechanisms other than STAT1 inhibition.Part Four The Construction of STAT1 Dominant Negative MutantAnd its Expression in Mammalian CellsObjectives: To construct the dominant negative mutant of STAT1 and express it in mammalian cells as a specific method in inhibiting STAT1 funcions. Methods: Total RNA was extracted from C57BL/6 mice lung tissue, RT-PCR was applied to acquire the intact ope...