Cellular prion protein expression in non-ciliated epithelial cells (Clara cells) of proliferating bronchioles during bleomycin-induced pulmonary fibrosis in hamster.
The cellular isoform of prion protein (PrPc) is a membrane glycoprotein with unknown roles. This study aimed to immunohistochemically demonstrate PrPc expression in normal and fibrotic hamster lungs. In untreated lungs, Clara cells, which were preferentially distributed in small bronchioles and characterized by globule granules, were positively stained. Reaction products were diffuse in the cytoplasm outside the granules and nuclei. In bleomycin-induced pulmonary fibrosis, bronchiolar proliferation was induced in the thickened fibrous tissue around terminal bronchioles. This event was characterized by accumulation of ductular structures which were predominantly lined by PrPc positive cells representative of Clara cells. Furthermore, PrPc positive cells were occasionally populated in the epithelium of alveolar ducts and reepithelialized alveoli. These findings suggest that Clara cells might undergo proliferation and migration into acini from terminal bronchioles. The fibrous tissue contained many alpha-smooth muscle actin positive myofibroblasts. The present study indicates that PrPc is expressed in Clara cells in normal and fibrotic hamster lungs and suggests that Clara cells may proliferate as pulmonary stem cells and repair the damaged epithelium after alveolar injuries.
Kadoya
H
H
Department of Anatomy, Osaka City University Medical School, Osaka, Japan.
Ikeda
K
K
Nakatani
K
K
Seki
S
S
Kaneda
K
K
D000818:Animals; D001761:Bleomycin; D001980:Bronchi / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D006224:Cricetinae; D008297:Male; D011328:Prions / Q000378:metabolism*; D011658:Pulmonary Fibrosis / Q000139:chemically induced* / Q000378:metabolism* / Q000473:pathology; D012016:Reference Values
D011328:Prions; D001761:Bleomycin