# Effect of Synthetic Vitreous Fiber Exposure on TMEM16A Channels in a Xenopus laevis Oocyte Model

## TL;DR

This study compares how synthetic vitreous fibers affect cell membranes, finding they cause some similar but less severe effects as asbestos.

## Contribution

The study introduces a novel comparison of synthetic vitreous fiber effects on cell membranes using a Xenopus laevis oocyte model.

## Key findings

- FAV173 fibers stimulate a chloride outward current blocked by TMEM16A antagonist Ani9.
- FAV173 fibers alter oocyte membrane microvilli morphology, likely via TMEM16A-actin interaction.
- FAV173 effects are less severe than crocidolite asbestos, even at higher concentrations.

## Abstract

Many years ago, asbestos fibers were banned and replaced by synthetic vitreous fibers because of their carcinogenicity. However, the toxicity of the latter fibers is still under debate, especially when it concerns the early fiber interactions with biological cell membranes. Here, we aimed to investigate the effects of a synthetic vitreous fiber named FAV173 on the Xenopus laevis oocyte membrane, the cell model we have already used to characterize the effect of crocidolite asbestos fiber exposure. Using an electrophysiological approach, we found that, similarly to crocidolite asbestos, FAV173 was able to stimulate a chloride outward current evoked by step membrane depolarizations, that was blocked by the potent and specific TMEM16A channel antagonist Ani9. Exposure to FAV173 fibers also altered the oocyte cell membrane microvilli morphology similarly to crocidolite fibers, most likely as a consequence of the TMEM16A protein interaction with actin. However, FAV173 only partially mimicked the crocidolite fibers effects, even at higher fiber suspension concentrations. As expected, the crocidolite fibers’ effect was more similar to that induced by the co-treatment with (Fe3+ + H2O2), since the iron content of asbestos fibers is known to trigger reactive oxygen species (ROS) production. Taken together, our findings suggest that FAV173 may be less harmful that crocidolite but not ineffective in altering cell membrane properties.