Polystyrene nanoplastics accumulate in ZFL cell lysosomes and in zebrafish larvae after acute exposure, inducing a synergistic immune response in vitro without affecting larval survival in vivo

Abstract

Polystyrene nanoplastics are internalized in zebrafish liver cells, accumulating in lysosomes, and in zebrafish larvae but do not affect the larval suvival to a lethal infection.

Nanoplastics Increase Fish Susceptibility to Nodavirus Infection and Reduce Antiviral Immune Responses

“…We failed to observe any changes in the gene expression related to the immune system upon NP exposure after 96 h in head-kidney, while some genes, mainly those related to inflammation, were sharply decreased in the liver. The poor negative effects may be directly related to the low doses used in this study in comparison with previous work: 0.1 µg g −1 (this study), 0.75 µg g −1 [15] or 111 µg g −1 [21] fish body weight. Nevertheless, after challenge with NNV, we observed a significant impact due to NP exposure.…”

“…A recent study demonstrated that viruses replicate faster and greater in the brain and spleen of orange-spotted grouper (Epinephelus coioides) juveniles exposed to NPs, thus accelerating fish mortality with respect to control treatments, but the final cumulative mortality was not altered [15]. The severity of disease seems to be related to the pathogen mode of infection since NP pre-exposure (5 and 50 µg mL −1 ) of zebrafish larvae did not impact the survival after infection with Aeromonas hydrophila [21]. Thus, data clearly suggest that NP exposure facilitates the early events of the disease but does not alter the final susceptibility.…”

“…There are contradictory results on this issue. A zebrafish cell line exposed to PS-NPs (50 nm) and poly (I:C), a viral RNA agonist, showed increased transcription of antiviral genes in presence of NPs at low doses (5 µg mL −1 ) when compared to poly (I:C) alone [21]. By contrast, fish GS cells exposed to NPs (50 µg mL −1 ) and then challenged with viruses showed a significant reduction in the transcription of Toll-like receptors (TLR1 and TLR9) and IFN (IFNr and IFNh) genes compared to those only infected [15].…”

“…Our first observations demonstrated that gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) exposed to MPs presented decreased immunity both in vitro and in vivo [19,20], probably caused by the increase of oxidative stress, which pointed to increased susceptibility to diseases. Exposed to polystyrene NPs, zebrafish (Danio rerio) larvae did not have altered susceptibly to Aeromonas hydrophila infection [21] while in orange-spotted grouper (Epinephelus coioides), reduced expression of toll-like receptor (TLR) and some interferon (IFN)-related genes occurred before and after NNV invasion, although fish mortality was not significantly affected [15]. Further studies are still needed to ascertain if the observed impaired immunity to mount an effective response might be linked to extended susceptibility to disease, as suggested.…”

Mechanisms of Silver Nanoparticle Uptake by Embryonic Zebrafish Cells

“…As an aquatic model, it also has advantages in terms of avoiding the ethical challenges associated with sentient organisms, supporting the transition to in vitro testing. In fact, zebrafish cells, such as embryonic zebrafish cells (ZF4) and zebrafish liver (ZFL) cells, have gained popularity in past years as a potential early-stage model, mainly for the assessment of toxicological and biological responses, including translational gene expression [21], bacterial invasion [22], assessment of pharmacological chemicals [23], and impacts from polystyrene [24,25] and metallic NPs [26][27][28]. To date, only a few studies have explored the trafficking and uptake mechanisms of nanomaterials in zebrafish cells, highlighting a key knowledge gap that needs to be urgently explored [24][25][26]28].…”