Chihiro Ozawa, Michiko Horiguc
Pulmonary emphysema is a disease in which alveoli in the lung are irreversibly destroyed, compromising lung function. All-trans-retinoic acid (ATRA) reportedly repairs the alveoli of emphysema model mice. In addition, ATRA can activate two nuclear receptors, nuclear retinoic acid receptor (RAR) and peroxisome proliferator-activated receptor (PPAR) β/δ. Both of these receptors induce differentiation in many different cell types. In this study, PPARβ/δ stimulation is shown to induce differentiation of human alveolar epithelial progenitor cells into alveolar type II epithelial (AT-II) cells. PPARβ/δ activation also stimulates the expression of adipose differentiation-related protein mRNA in human alveolar epithelial progenitor cells. These data suggest that PPARβ/δ selective agonists could differentiate human alveolar epithelial progenitor cells without cytotoxic of ATRA derived from stimulation to RAR.