Receptor role of the annexin A2 in the mesothelial endocytosis of crocidolite fibers

Abstract

Asbestos-induced mesothelioma is a worldwide problem. Parietal mesothelial cells internalize asbestos fibers that traverse the entire lung parenchyma, an action that is linked to mesothelial carcinogenesis. Thus far, vitronectin purified from serum reportedly enhances the internalization of crocidolite by mesothelial cells via integrin avb5. To reveal another mechanism by which mesothelial cells endocytose (phagocytose) asbestos, we first evaluated the effects of serum on asbestos uptake, which proved to be nonessential. Thereafter, we undertook a study to identify proteins on the surface of mesothelial cells (MeT5A) that act as receptors for asbestos uptake based on the assumption that receptors bind to asbestos with physical affinity. To this end, we incubated the membrane fraction of MeT5A cells with crocidolite or chrysotile and evaluated the adsorbed proteins using sodium dodecyl sulfate polyacrylamide gel analysis. Next, we extensively identified the proteins using an in-solution or in-gel digestion coupled with mass spectrometry. Among the identified proteins, annexin A2 (ANXA2) and transferrin receptor protein 1 (TFRC) were distinguished because of their high score and presence at the cell surface. Crocidolite uptake by MeT5A cells was significantly decreased by shRNA (short hairpin RNA)-induced knockdown of ANXA2 and direct blockade of cell surface ANXA2 using anti-ANXA2 antibody. In addition, abundant ANXA2 protein was present on the cell membrane of mesothelial cells, particularly facing the somatic cavity. These findings demonstrate that ANXA2 has a role in the mesothelial phagocytosis of crocidolite and may serve as its receptor.

The origin and future of oxidative stress pathology: From the recognition of carcinogenesis as an iron addiction with ferroptosis‐resistance to non‐thermal plasma therapy

“…Mesothelial cells, the target of this carcinogenesis, are extremely unique cells in many aspects. 113,114 In 2006, finally all asbestos was legally banned in Japan and a law was enacted to financially support all of the current malignant mesothelioma Figure 5 General rule on iron metabolism in parenchymal cells in various pathologic conditions. This is based on the fact that iron has been essential and precious for every species during evolution, which eventually leads to an ultimate choice issue in higher organisms with long lifetime.…”

“…After this event, our group began to study asbestos‐induced mesothelial carcinogenesis. Mesothelial cells, the target of this carcinogenesis, are extremely unique cells in many aspects . In 2006, finally all asbestos was legally banned in Japan and a law was enacted to financially support all of the current malignant mesothelioma patients and the families of already deceased patients.…”

Malignant mesothelioma as an oxidative stress-induced cancer: An update

“…Mesothelial cells take up asbestos fibers and the internalized fibers can cause DNA doublestrand breaks [33,51] or mechanical disruption of the mitotic spindle during cell division, resulting in chromosomal abnormalities such as aneuploidy [52][53][54][55]. We recently identified annexin A2 as a candidate receptor of asbestos for this process [56].…”

Role of hemoglobin and transferrin in multi‐wall carbon nanotube‐induced mesothelial injury and carcinogenesis

“…Mass spectrometric identification of the proteins was performed as described previously. (19,23) Briefly, for in-gel digestion, proteins run on SDS-PAGE were visualized with silver staining; each band was excised from the gels and subjected to in-gel digestion with trypsin in a buffer containing 25 mM ammonium bicarbonate overnight at 37°C. For insolution digestion, the proteins were detached from MWCNT by degeneration with guanidinium chloride and digested with trypsin in the same manner.…”