Cross-Species Comparisons of Nanoparticle Interactions with Innate Immune Systems: A Methodological Review

Abstract

Many components of the innate immune system are evolutionarily conserved and shared across many living organisms, from plants and invertebrates to humans. Therefore, these shared features can allow the comparative study of potentially dangerous substances, such as engineered nanoparticles (NPs). However, differences of methodology and procedure between diverse species and models make comparison of innate immune responses to NPs between organisms difficult in many cases. To this aim, this review provides an overview of suitable methods and assays that can be used to measure NP immune interactions across species in a multidisciplinary approach. The first part of this review describes the main innate immune defense characteristics of the selected models that can be associated to NPs exposure. In the second part, the different modes of exposure to NPs across models (considering isolated cells or whole organisms) and the main endpoints measured are discussed. In this synergistic perspective, we provide an overview of the current state of important cross-disciplinary immunological models to study NP-immune interactions and identify future research needs. As such, this paper could be used as a methodological reference point for future nano-immunosafety studies.

Keywords: NPs testing; environmental models; human cells; innate immunity; markers.

Figure 5

The different in vitro NP exposure possibilities available for human primary cells and the procedure of cell extraction and preparation (Reprinted with permission from Michelini et al. (2021) [153]. Copyright 2021, Copyright Royal Society of Chemistry).

Figure 1

The different exposure pathways of engineered NPs that can interact with human or environmental species.

Figure 2

The different models discussed in the current review, and their main experimental usage in the laboratory: in vivo (whole organism experiments) and in vitro (isolated cells or cell lines).

Figure 3

The different characteristics of NPs and parameters to investigate when they are in suspension media for laboratory experiments.

Figure 4

The different in vitro approaches and NPs exposure parameters encountered across the selected models.

Figure 6

NP exposure approaches using the whole organism with the different exposure pathways across the selected models.

Figure 7

Summary of the different endpoints measured in immune cells after exposure to NPs.

Figure 8

Proposal template for translatable NP experiments across the models of interest (plants, terrestrial and marine invertebrates, and human cells).