Page 36 - Read Online

Page 4 of 15 Macpherson et al. Microbiome Res Rep 2024;3:20 https://dx.doi.org/10.20517/mrr.2023.66

Figure 1. Venn diagram illustrating culture condition requirements of insect and mammalian cell lines. Insect and mammalian cell lines
share many nutritional requirements, but differ in their environmental conditions, with insect cell lines notably requiring a lower
[20]
resource demand. Created with BioRender.com .
ZOOMING IN: THE POTENTIAL OF INSECT GUT CELL LINES TO IMPROVE OUR
UNDERSTANDING OF THE MICROBIOME
Cell lines have served as valuable tools in the understanding of host-microbe interactions in insects. The
predominant focus of these studies, however, has been the investigation of host-pathogen relationships;
nominal research has explored the impact of symbionts on the host and no research has studied microbial
communities, including those of the gut. In this review, we separate the study of pathogens from the study
of the microbiome and emphasize studies using cell lines to understand host-symbiont relationships and the
impact of microbial communities on insect health. Studies have yet to explore the use of insect gut cell lines
to understand host-microbial relationships, although several studies utilize other tissues for this purpose.

One study that utilized insect cell culture to investigate a symbiont-host interaction in mosquitos (Aedes
fluviatilis) observed that cultured embryonic cells infected with the obligate endosymbiont Wolbachia
pipientis displayed improved energy performance and innate immune system activation . Other studies
[25]
have employed cell lines to elucidate the molecular mechanisms of bacterial infiltration into host cells. For
example, a study found that an unclassified Rickettsia sp., an endosymbiont of rice green leafhopper
(Nephotettix cincticeps) sperm, could migrate to the nucleus of two larval cell lines belonging to different
phylogenetic orders . This work provides unique insight into endosymbiotic theory and the vertical
[26]
transmission of microbes between hosts. Another avenue for the use of insect cell culture in microbiome
research is in the culture of sensitive microorganisms that benefit from the presence of host tissue . These
[27]
cultured microbes may then be used to perform in vitro or in vivo assays. Several intracellular microbes,
[28]
such as the previously mentioned W. pipientis, have been cultured in this manner . This diverse array of
uses underscores both the versatility and potential of insect cell lines in microbiome research.

The insect gut microbiome has evolved alongside its host over millions of years, forming an intimate and
often life-sustaining bond [29,30] . Microbes provide insect hosts with essential nutrient provisioning, aid in