Gut Check: using transfection to study the gut microbiome’s role in inflammation

Today’s SNiP reminds us that we are never truly alone. It’s been estimated that over one trillion microbial cells inhabit the human body.¹ The vast majority of these microbes are bacteria that live in the colon (>99%).^1,2 For the most part, the relationship is commensal; in other words, generally, our microbial residents neither help, nor harm us. However, research increasingly shows that some of the microbes that visit and inhabit our gut are not passive occupants.

In this study, Wojciech et al. implicate a eukaryotic gut-dwelling microbe, Blastocystis subtype 7 (ST7), in promoting inflammation of the gut. World-wide, prevalence of Blastocystis in the population ranges from 18-40%, and ST1-8 are found in asymptomatic and symptomatic people alike.³ Wojciech et al. identify indole-3-acetaldehyde (I3AA) as a metabolite that is significantly elevated during Blastocystis ST7 infection. They show that an enzyme from Blastocystis ST7 (D8M7V4) promotes the generation of I3AA. Furthermore, infection with Blastocystis ST7, direct addition of I3AA or over-expression of D8M7V4 are all capable of effecting host T cell dysregulation, providing a mechanism for how this microbe can cause inflammation in the gut.

Read the paper to learn more about Blastocystis and I3AA, both of which may be targets for treating irritable bowel disease!

Citation

Title: A tryptophan metabolite made by a gut microbiome eukaryote induces pro-inflammatory T cells
Authors: Lukasz Wojciech, Chin Wen Png et al.
Journal: The EMBO Journal, Volume 42, September 2023.
DOI: 10.15252/embj.2022112963
Product Usage: TransIT^®-mRNA Transfection Kit was used to transfect HEK 293 cells with in vitro transcribed mRNA encoding D8M7V4 or a BFP control. T cell hybridomas stably expressing Cas9 were transfected with gRNA using TransIT-TKO^® Transfection Reagent in order to deplete expression of the aryl hydrocarbon receptor (AhR) gene, which is known to regulate immune homeostasis in the gut.