Expression of PU.1 and terminal differentiation of alveolar macrophages in newborn rats.
PU.1, which is a transcription factor, promotes the terminal differentiation of alveolar macrophages (AMs). Its expression is regulated by granulocyte/macrophage colony-stimulating factor (GM-CSF). In this study of AMs in newborn rats, we performed immunohistochemical staining, acid phosphatase staining, reverse transcriptase polymerase chain reaction (RT-PCR), quantitative real-time PCR, cytokine assay, and electron microscopy. AMs at 3 and 7 days after birth had a large foamy appearance with an intracytoplasmic accumulation of surfactants. Weak expression of PU.1 was observed in the nuclei. AMs at 15 days after birth were smaller, and PU.1 expression had increased. Ultrastructurally, AMs at 1 day after birth had a smooth surface and abundant lamellar structures in the cytoplasm, whereas AMs at 56 days after birth were characterized by (1) abundant microvillar projections on the cell surface, and (2) well-developed lysosomes and a few lamellar structures in the cytoplasm. Acid phosphatase activity and the expression of mannose receptor, scavenger receptor, and GM-CSF receptor alpha were enhanced in AMs with time after birth. These results suggest that AMs are initially immature, and that their terminal differentiation starts after birth concomitantly with an increased expression of PU.1.
Iwabuchi
Haruko
H
Division of Cellular and Molecular Pathology, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510, Japan.
Kawasaki
Takashi
T
Yamamoto
Takashi
T
Uchiyama
Makoto
M
Nakata
Koh
K
Naito
Makoto
M
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D003593:Cytoplasm / Q000378:metabolism / Q000648:ultrastructure; D005786:Gene Expression Regulation / Q000502:physiology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000378:metabolism* / Q000648:ultrastructure; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D011663:Pulmonary Surfactants / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011956:Receptors, Cell Surface / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000096:biosynthesis*; D000099232:Proto-Oncogene Protein Spi-1
D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D011518:Proto-Oncogene Proteins; D011663:Pulmonary Surfactants; D011956:Receptors, Cell Surface; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1