Diesel Exhaust Particle (DEP)-induced glucose intolerance is driven by an intestinal innate immune response and NLRP3 activation in mice

Angela J T Bosch; Theresa V Rohm; Shefaa AlAsfoor; Andy J Y Low; Zora Baumann; Neena Parayil; Faiza Noreen; Julien Roux; Daniel T Meier; Claudia Cavelti-Weder

doi:10.1186/s12989-023-00536-8

Diesel Exhaust Particle (DEP)-induced glucose intolerance is driven by an intestinal innate immune response and NLRP3 activation in mice

Part Fibre Toxicol. 2023 Jul 3;20(1):25. doi: 10.1186/s12989-023-00536-8.

Authors

Angela J T Bosch¹, Theresa V Rohm¹, Shefaa AlAsfoor¹, Andy J Y Low¹, Zora Baumann¹, Neena Parayil¹, Faiza Noreen^{1

2}, Julien Roux^{1

2}, Daniel T Meier¹, Claudia Cavelti-Weder^{3

4

5

6}

Affiliations

¹ Department of Biomedicine, University of Basel, Basel, 4031, Switzerland.
² Swiss Institute of Bioinformatics, Basel, 4031, Switzerland.
³ Department of Biomedicine, University of Basel, Basel, 4031, Switzerland. claudia.cavelti-weder@usz.ch.
⁴ Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, 4031, Switzerland. claudia.cavelti-weder@usz.ch.
⁵ Department of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Zurich (USZ) and University of Zurich (UZH), Zurich, Switzerland. claudia.cavelti-weder@usz.ch.
⁶ University Hospital Zurich, Rämistrasse 100, Zürich, 8009, Switzerland. claudia.cavelti-weder@usz.ch.

Abstract

Background: We previously found that air pollution particles reaching the gastrointestinal tract elicit gut inflammation as shown by up-regulated gene expression of pro-inflammatory cytokines and monocyte/macrophage markers. This inflammatory response was associated with beta-cell dysfunction and glucose intolerance. So far, it remains unclear whether gut inflammatory changes upon oral air pollution exposure are causally linked to the development of diabetes. Hence, our aim was to assess the role of immune cells in mediating glucose intolerance instigated by orally administered air pollutants.

Methods: To assess immune-mediated mechanisms underlying air pollution-induced glucose intolerance, we administered diesel exhaust particles (DEP; NIST 1650b, 12 µg five days/week) or phosphate-buffered saline (PBS) via gavage for up to 10 months to wild-type mice and mice with genetic or pharmacological depletion of innate or adaptive immune cells. We performed unbiased RNA-sequencing of intestinal macrophages to elucidate signaling pathways that could be pharmacologically targeted and applied an in vitro approach to confirm these pathways.

Results: Oral exposure to air pollution particles induced an interferon and inflammatory signature in colon macrophages together with a decrease of CCR2^- anti-inflammatory/resident macrophages. Depletion of macrophages, NLRP3 or IL-1β protected mice from air pollution-induced glucose intolerance. On the contrary, Rag2-/- mice lacking adaptive immune cells developed pronounced gut inflammation and glucose intolerance upon oral DEP exposure.

Conclusion: In mice, oral exposure to air pollution particles triggers an immune-mediated response in intestinal macrophages that contributes to the development of a diabetes-like phenotype. These findings point towards new pharmacologic targets in diabetes instigated by air pollution particles.

Keywords: Air pollution; Diesel exhaust particles; Gastrointestinal tract; Glucose metabolism; Gut exposure; IL-1β; Innate immune response; Macrophages; Metabolic disease; NLRP3.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Glucose Intolerance* / chemically induced
Immunity, Innate
Inflammation
Mice
NLR Family, Pyrin Domain-Containing 3 Protein / genetics
Vehicle Emissions* / toxicity

Substances

Vehicle Emissions
NLR Family, Pyrin Domain-Containing 3 Protein