Phagocytosis of crocidolite asbestos induces oxidative stress, DNA damage,and apoptosis in mesothelial cells

Citation
Wh. Liu et al., Phagocytosis of crocidolite asbestos induces oxidative stress, DNA damage,and apoptosis in mesothelial cells, AM J RESP C, 23(3), 2000, pp. 371-378
Citations number
39
Categorie Soggetti
da verificare
Journal title
AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY
ISSN journal
10441549 → ACNP
Volume
23
Issue
3
Year of publication
2000
Pages
371 - 378
Database
ISI
SICI code
1044-1549(200009)23:3<371:POCAIO>2.0.ZU;2-K
Abstract
Phagocytosis of asbestos fibers may be a necessary step for asbestos-induce d injury to mesothelial cells, but this has not been established because qu antification of fiber uptake is difficult and ways to increase fiber phagoc ytosis without also increasing total dose were not available, We quantified phagocytosis by counting intracellular fibers after removing adherent fibe rs with trypsin; we selectively increased fiber phagocytosis by coating cro cidolite asbestos fibers with the adhesive serum protein vitronectin (VN), which we have shown increases fiber uptake via integrins. We measured vario us aspects of asbestos-induced cytotoxicity: intracellular oxidation by the shift of fluorescence of cells loaded with an oxidative probe, DNA strand breakage by the alkaline unwinding ethidium bromide fluorometric assay, apo ptosis by annexin V binding and by nuclear morphology, and cell-cycle progr ession. We found that, compared with control fibers or particles, asbestos increased intracellular oxidation, DNA strand breakage, and apoptosis, Sele ctive increases in fiber uptake by VN-coating of the fibers further increas ed the oxidation, DNA strand breakage, and apoptosis, and induced a cell-cy cle arrest in G2/M. Selective decreases in fiber uptake by cytochalasin or by integrin blockade with RGD peptides inhibited several of these measures of injury. We conclude that phagocytosis is important and perhaps necessary for asbestos-induced injury to mesothelial cells.