Endocytosis in cultured rat alveolar type II cells: effect of lysosomotropic weak bases on the processes.
We investigated the uptake of Lucifer yellow and surfactant complexed with gold (S-G) by isolated alveolar Type II cells. The fluid phase marker Lucifer yellow did not reach lamellar bodies (LB) even after prolonged incubation time, whereas S-G was internalized and found in LB. Treatment of Type II cells with lysosomotropic weak bases (NH4Cl and chloroquine) resulted in dilation of endosomes, lysosomes, and LB. The effect of these agents on LB resulted in disappearance of their lamellar organization, as detected by polarized light and electron microscopy. After incubation in lysosomotropic agent-free medium, endocytosis of Lucifer yellow and S-G in treated cells was mainly directed towards large vacuoles resembling either multivesicular bodies (MVB) or lysosomes. The possible relationship between LB, MVB, and lysosomes in freshly isolated as well as cultured alveolar Type II cells is discussed.
Kalina
M
M
Department of Histology and Cell Biology, Sackler School of Medicine, Tel-Aviv University, Israel.
Socher
R
R
D000643:Ammonium Chloride / Q000494:pharmacology*; D000818:Animals; D001718:Birefringence; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D006651:Histocytochemistry; D002479:Inclusion Bodies / Q000187:drug effects; D007546:Isoquinolines / Q000378:metabolism / Q000493:pharmacokinetics; D008247:Lysosomes / Q000187:drug effects; D008297:Male; D008854:Microscopy, Electron; D008859:Microscopy, Polarization; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D011663:Pulmonary Surfactants / Q000378:metabolism / Q000493:pharmacokinetics; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D007546:Isoquinolines; D011663:Pulmonary Surfactants; D000643:Ammonium Chloride; D002738:Chloroquine; C017475:lucifer yellow