| Summary: | 博士 === 國立臺灣大學 === 免疫學研究所 === 103 === Asthma is characterized by chronic airway inflammation and hyperresponsiveness (AHR). Little is known about the role of pulmonary stem cells (PSCs) in allergic airway inflammation. To identify the role of PSCs population in the bronchial epithelium of neonatal mice, we developed an enzyme-based digestion method to isolate PSCs from lung tissues. Characterization of PSCs was done using flow cytometry, real-time PCR, immunofluorescence staining, confocal microscopy, and scanning electron microscopy. The effects of SSEA-1+ PSCs was studied in an in vivo model of ovalbumin-induced allergic inflammation and an in vitro model of cell-based regulation using flow cytometry, enzyme-linked immunosorbent assay, real-time PCR, and immune-blotting. Cell suspensions derived from neonatal lung tissue contained cells expressing either SSEA-1+ (stage-specific embryonic antigen-1) or Sca-1+ (stem cell antigen-1) that represent PSCs phenotype. The SSEA-1+ PSCs were prevalent in neonatal mice, but rare in adult mice. Enriched SSEA-1+ PSCs had the ability to differentiate into pneumocytes and tracheal epithelial cells. The expression of CCSP (Clara cell secretory protein) were higher in SSEA-1+ PSCs as compared with that of SSEA-1- pulmonary cells. Transplantation of SSEA-1+ PSCs in asthmatic mice reduced AHR and airway damage by decreasing eosinophil infiltration, inhibiting chemokines/cytokines production, increasing regulatory T cells, and preserving the level of CCSP. Collectively, our results indicated that neonatal SSEA-1+ PSCs contribute to ameliorate the progression of asthma by reducing lung damage and inhibiting inflammatory responses. Study about the molecular mechanisms of neonatal SSEA-1+ PSCs might shed light on etiology of airway inflammation.
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