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P079 Trehalose ameliorates colitis by increasing mucosal autophagy and M2 polarisation

J. Cosin-Roger*1, D. Ortiz-Masia1, D. C. Macias-Ceja2, P. Salvador1, L. Gisbert-Ferrandiz1, C. Hernandez2, S. Calatayud1, M. D. Barrachina1

1University of Valencia, Valencia, Spain, 2Fisabio Hospital Peset, Valencia, Spain

Background

Several polymorphisms in gene loci containing autophagy-related proteins such as ATG16L1, IRGM, and NOD2 have been associated with an increased risk of Crohn’s disease, suggesting that a defective autophagy may have a role in its pathogenesis. Autophagy has been shown to mediate macrophage polarisation towards the anti-inflammatory phenotype M2a, and we have demonstrated that these macrophages mediate mucosal healing in a murine model of colitis. We analyse the effects of trehalose, an mTOR independent autophagy-inducer, in macrophage polarisation and mucosal regeneration in a murine model of colitis.

Methods

Balbc mice received trehalose (3%) in the drinking water during 3 weeks before an intrarectal injection of TNBS (3,5mg/20g) or its vehicle (40% EtOH) (day 0). Changes in body weight were determined daily (results are expressed as % vs the weight at day 0), and mice were sacrificed 4 days after TNBS administration. Mucosal histology was evaluated according to Wallace score (1–10). Colons were frozen, and the expression of M1 and M2 markers and pro-inflammatory cytokines was analysed by qPCR (results are expressed as fold induction). The mucosal autophagic flux was determined by analysing protein levels of p62 and LC3 by Western blot. Data are expressed as Mean ± SEM with n ≥ 5 in all groups.

Results

TNBS administration induced a loss of body weight and mucosal damage that peaked 2 days after treatment and after that mice started to recover. Chronic treatment with trehalose: a) significantly attenuated the loss of body weight at day 1 and 2 (92.9 ± 1.3 and 96.5 ± 1.4, respectively) compared with vehicle-treated mice (90.2 ± 0.8 and 91.3 ± 1.7, respectively); b) reduced the histological damage score (4.3 ± 0.4) compared with vehicle-treated mice (5.5 ± 0.6); c) reduced the expression of TNF-α (1.1 ± 0.2), IL-1β (0.7 ± 0.1) and IL-6 (1.4 ± 0.2), compared with that observed in vehicle-TNBS-treated mice (2.5 ± 0.6, 1.9 ± 0.3 and 4.6 ± 1.4, respectively); d) reduced the expression of M1 associated genes, iNOS (0.8 ± 0.2), CCR7 (0.7 ± 0.3), CD11c (0.8 ± 0.1), and CD86 (1.1 ± 0.4), and increased the expression of M2 associated genes, CD206 (3.8 ± 0.5), ArgI (27.1 ± 5.9), Fizz1 (0.5 ± 0.3) and Ym1 (21.8 ± 4.2), compared with vehicle-TNBS-treated mice (5.3 ± 1.8, 2.4 ± 0.5, 1.9 ± 0.3, 2.8 ± 0.7, 2.3 ± 0.6, 20.1 ± 6.0, 0.2 ± 0.1 and 9.4 ± 2.8, respectively). Activation of colonic autophagy by trehalose was confirmed by the decreased expression of p62 and the increased expression of LC3II detected in the mucosa of both Vh and TNBS-treated mice.

Conclusion

Chronic treatment with trehalose increases mucosal autophagy and promotes M2 polarisation in the mucosa of TNBS-treated mice, which improves wound healing and functional recovery of mice.