Aggregation of fibronectin by asbestos fibers in the pericellular matrix of cultured human fibroblasts

Our plain-English summary of Aggregation of fibronectin by asbestos fibers in the pericellular matrix of cultured human fibroblasts, by T. Vartio, I. Virtanen, V.P. Lehto (Acta Pathologica, Microbiologica, et Immunologica Scandinavica. Section A, Pathology, 1986).

The study

• Authors: T. Vartio, I. Virtanen, V.P. Lehto
• Journal: Acta Pathologica, Microbiologica, et Immunologica Scandinavica. Section A, Pathology
• Published: 1986;94(3):169-75
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestos fibers, silica dust and glass fibers induced aggregation of the pericellular matrix fibronectin when added to the growth medium of cultured human fibroblasts as judged by immunofluorescence microscopy. Direct binding experiments and analysis of the bound proteins by (SDS-polyacrylamide gel electrophoresis) revealed an adsorption of purified plasma fibronectin to glass fibers, amosite, crocidolite and silica but not to anthophyllite and chrysotile A and B. The results suggest that aggregation of the pericellular fibronectin by these fibrogenic materials may be involved in the initial stages of the development of fibrosis in vivo.

In plain English

This was a laboratory experiment on human cells, not a study of people. The authors, at the University of Helsinki, added standard UICC samples of chrysotile A and B, crocidolite, amosite and anthophyllite asbestos, plus respirable glass fibers and silica powder, to cultures of human embryonic skin fibroblasts. The doses were 10 or 100 micrograms per ml. They used fluorescent antibody staining to see fibronectin, a protein in the material surrounding the cells. After 8 hours the fibronectin network looked like that in untreated cultures. After 24 hours, fibronectin had clumped where asbestos, glass fibers or silica particles gathered. Chrysotile A, chrysotile B and amosite appeared toxic to the cells, and some cells detached. The authors could not measure clumping precisely, but their impression was that anthophyllite and crocidolite were most effective. The two doses gave no significant difference in staining. In a separate test with purified fibronectin, glass fibers, amosite, crocidolite and silica bound it well. Anthophyllite and both chrysotiles bound only negligible amounts. The authors suggested this interaction may be an early event in the development of fibrosis in the body.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: laboratory (in vitro) cell culture experiment, with a separate test of purified protein binding to minerals
• Who was studied: cultured human embryonic skin fibroblasts (cells, not people), grown to subconfluent or confluent state; work done at the University of Helsinki, Finland; purified human plasma fibronectin was also used
• Exposure: UICC standard samples of chrysotile A, chrysotile B, crocidolite, amosite and anthophyllite asbestos, plus respirable glass fibers and silica powder, added to serum-free growth medium at 10 and 100 micrograms per ml
• Main results:
  • In subconfluent cultures 8 hours after the minerals were added, the fibronectin network looked as it did in control cultures
  • After 24 hours, fibronectin around the cells had aggregated at the sites where asbestos, glass fibers or silica particles had gathered
  • Chrysotile A, chrysotile B and amosite appeared cytotoxic, leading to partial detachment of cells from the culture surface
  • Aggregation could not be accurately quantified, but the authors' impression was that anthophyllite and crocidolite were the most effective at aggregating fibronectin in the cell cultures
  • In the cell-culture summary table, chrysotile A and chrysotile B were each scored as showing no fibronectin binding and as cytotoxic
  • No significant differences in fibronectin staining were seen between the 10 and 100 micrograms per ml doses
  • Essentially similar fibronectin aggregation was seen in confluent cell cultures
  • When minerals were mixed with purified human plasma fibronectin, glass fibers, amosite, crocidolite and silica bound fibronectin well
  • In the same purified-fibronectin test, anthophyllite, chrysotile A and chrysotile B bound only negligible amounts
• The authors' conclusion: The authors concluded that the fibrogenic materials caused extensive aggregation of fibronectin around the cells, possibly through direct binding. They suggested that the interaction between asbestos particles and fibronectin may be an initial event in collagen accumulation and the development of fibrosis in the body.
• Limitations the authors state:
  • The immunofluorescence images did not allow accurate measurement of how much fibronectin aggregation each mineral caused

Topics

Medical terms in this study, explained in our Lexicon: Fibroblast, Amosite, Crocidolite, Anthophyllite, Chrysotile, Fibrogenic, Fibrosis.

Related studies

• Tenascin and fibronectin expression in human mesothelial cells and pleural mesothelioma cell-line cells — V.L. Kinnula, A. Linnala, et al. (1998)
• Pulmonary and pleural leukocytes from F344 rats produce elevated levels of fibronectin following inhalation of refractory ceramic fibers — T.R. Gelzleichter, J.B. Mangum, et al. (1996)
• Fibronectin and procollagen 3 levels in bronchoalveolar lavage of asbestos-exposed human subjects and sheep — R. Bégin, M. Martel, et al. (1986)
• Peroxisome proliferator-activated receptor-gamma ligands suppress fibronectin gene expression in human lung carcinoma cells: involvement of both CRE and Sp1 — S. Han, J.D. Ritzenthaler, et al. (2005)
• Secretion of fibronectin by mineral dust-derived alveolar macrophages and activated peritoneal macrophages — R. Davies, G. Erdogdu (1989)
• Fibronectin expression and organization in mesothelial and mesothelioma cells — P.C. Ferriola, W. Stewart (1996)

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