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
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.