An IBD-associated pathobiont synergises with NSAID to promote colitis which is blocked by NLRP3 inflammasome and Caspase-8 inhibitors

ABSTRACT

Conflicting evidence exists on the association between consumption of non-steroidal anti-inflammatory drugs (NSAIDs) and symptomatic worsening of inflammatory bowel disease (IBD). We hypothesized that the heterogeneous prevalence of pathobionts [e.g., adherent-invasive Escherichia coli (AIEC)], might explain this inconsistent NSAIDs/IBD correlation. Using IL10^−/− mice, we found that NSAID aggravated colitis in AIEC-colonized animals. This was accompanied by activation of the NLRP3 inflammasome, Caspase-8, apoptosis, and pyroptosis, features not seen in mice exposed to AIEC or NSAID alone, revealing an AIEC/NSAID synergistic effect. Inhibition of NLRP3 or Caspase-8 activity ameliorated colitis, with reduction in NLRP3 inflammasome activation, cell death markers, activated T-cells and macrophages, improved histology, and increased abundance of Clostridium cluster XIVa species. Our findings provide new insights into how NSAIDs and an opportunistic gut-pathobiont can synergize to worsen IBD symptoms. Targeting the NLRP3 inflammasome or Caspase-8 could be a potential therapeutic strategy in IBD patients with gut inflammation, which is worsened by NSAIDs.

KEYWORDS:

• AIEC
• piroxicam
• inflammatory bowel disease
• cell death
• IL10^−/− mice
• inflammasome

Acknowledgments

We acknowledge and thank the APC Microbiome Ireland Flow Cytometry Platform and the support of the staff at the BSU-Annex, University College Cork. We thank the technical assistance of Ms Juliet Barry, Department of Pathology, University College Cork in sectioning and H&E and Alcian blue/PAS staining. The author’s original manuscript has been posted on bioRxiv server.⁶⁸

Author contributions

RS – conceived, designed, and carried most of the experiments, analyzed related data, wrote the initial manuscript and edited the paper; VR – designed, carried out and analyzed flow cytometry experiments and executed animal experiments; SRS, AC – analyzed and graphed microbiota analysis; GS-G, NH, TD’S – carried out the animal experiments, dissected tissue and cells, and staining of cells for flow cytometry; LD, CH – supervised microbiota analysis and edited paper; KN, FS, SA-E – reviewed and edited paper; SM – conceived, designed, and supervised the research and reviewed and edited the paper. FS, SA-E, SM – funding acquisition. All authors contributed to the article and approved the submitted version.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

Raw sequence data from mouse fecal samples have been deposited in the NCBI SRA database under the Bioproject ID PRJNA849757 (https://www.ncbi.nlm.nih.gov/bioproject/PRJNA849757). This paper does not report any original code. Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19490976.2022.2163838

Additional information

Funding

This work and the authors were supported by the Science Foundation Ireland (SFI) Research Centre awards SFI/12/RC/2273-P1 and SFI/12/RC/2273-P2 to APC Microbiome Ireland and SFI Professor award grant number SFI/15/RP/2828 to SA-E. GS-G is a recipient of a Government of Ireland Postgraduate Scholarship (grant GOIPG/2019/4528).