Protein abnormalities in macrophages bearing asbestos

Our plain-English summary of Protein abnormalities in macrophages bearing asbestos, by P. Lemkin, L. Lipkin, C. Merril, et al (Environmental Health Perspectives, 1980).

The study

• Authors: P. Lemkin, L. Lipkin, C. Merril, S. Shifrin
• Journal: Environmental Health Perspectives
• Published: 1980;34:75-89
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Computerized techniques for the evaluation of O'Farrell two-dimensional electrophoretic gels have been applied to proteins derived from asbestos bearing macrophages. Preliminary results indicate definite changes in the protein content of cells depending on fiber phagocytosis.

In plain English

This was a laboratory study of cultured cells, not people. The authors exposed P388D1 macrophage-like cells, a mouse tumor cell line, to 50 micrograms per cubic centimeter of standard UICC amosite asbestos. They compared the cells' proteins with unexposed control cells at 24, 48 and 72 hours using two-dimensional gel electrophoresis and computer image analysis. Amosite-exposed cells looked flatter, stuck more to glass and moved less, but still divided. At 48 hours, several protein spots present in control gels were missing from asbestos gels. This was not seen at 24 or 72 hours. At 72 hours, the left of two adjacent spots near molecular weight 45,000, in what the authors called the actin complex, looked considerably lighter in the asbestos gel. The proteins had not been identified, and the two spots might be one protein differing in charge. Density measurements showed changes in both directions, which the authors called preliminary and not yet clear. The authors concluded that amosite produced numerous protein changes in these cells. They noted that asbestos toxicity altered how many cells and how much protein each experiment yielded.

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 cell-culture experiment comparing amosite-exposed and control cells by two-dimensional gel electrophoresis with computer-assisted gel image analysis; described by the authors as preliminary
• Who was studied: P388D1 macrophage-like cells, a cell line originally derived from a DBA mouse tumor, grown as monolayers in tissue culture; control and amosite-exposed gels at 24, 48 and 72 hours
• Exposure: UICC standard amosite B preparation at 50 micrograms per cubic centimeter; cells labeled with carbon-14 amino acids 24 hours before harvesting
• Main results:
  • Cells exposed to amosite were flatter and more adherent to glass, and showed less translational motion, under differential interference microscopy
  • Cell division (mitosis) was still observed in asbestos-bearing cells
  • At 48 hours, spots present in the control gel were missing in the asbestos gel
  • The 48-hour spot differences were not seen in the 24-hour and 72-hour samples
  • At 72 hours, the leftmost of two spots near molecular weight 45,000, in what the authors called the actin complex, appeared considerably lighter in the amosite gel than in the control gel; the proteins' identities had not been confirmed
  • The authors said the two major spots near molecular weight 45,000 sometimes merged and might be a single protein differing by charge
  • Normalized density ratios of amosite to control for 13 spots showed protein concentration changes in both directions; the authors said apparent changes in actin were not yet clear
  • The authors stated that cell and fiber loss from the 48-hour medium change could not account for all of the observed changes
• The authors' conclusion: The authors concluded that amosite asbestos produced numerous changes in the protein composition of the macrophage-like cells. They said the proteins involved still had to be identified.
• Limitations the authors state:
  • The spot data analysis was preliminary and needed more experiments before it could be reliably interpreted
  • The cytotoxic effect of asbestos affected the number of cells and amount of protein from each experiment, making equal protein loading and equal labeling difficult
  • The proteins corresponding to the spot differences were not identified
  • A required medium change at about 48 hours caused cell and fiber loss, estimated at an upper limit of about 10%, which must be considered for the 72-hour results
  • The cell line is derived from a mouse tumor and is malignant, not true macrophages
  • More extensive controls were still needed; the experiments were being repeated

Topics

Medical terms in this study, explained in our Lexicon: Macrophage, Phagocytosis.

Related studies

• A secretomics analysis reveals major differences in the macrophage responses towards different types of carbon nanotubes — J. Palomäki, J. Sund, et al. (2015)
• Factors involved in the cytotoxicity of UICC amosite towards macrophages — R. Davies, D.M. Griffiths, et al. (1983)
• Effect of SiO2-liberated macrophage factor on protein synthesis in connective tissue in vitro — M. Aalto, H. Turakainen, et al. (1979)
• Angiogenesis correlates with macrophage and mast cell infiltration in lung tissue of animals exposed to fluoro-edenite fibers — G. Musumeci, C. Loreto, et al. (2016)
• Mechanisms of macrophage accumulation in the lungs of asbestos-exposed subjects — J.R. Spurzem, C. Saltini, et al. (1987)
• Alternative activation of macrophages and pulmonary fibrosis are modulated by scavenger receptor, macrophage receptor with collagenous structure — S. Murthy, J.L. Larson-Casey, et al. (2015)

Browse more research in Environmental Health Perspectives, or return to medical research.