P0069 TP-317, a Novel BLT1 Agonist Oral Therapy for Inflammatory Bowel Disease, Exhibits Anti-Inflammatory and Epithelial Barrier Protective Efficacy in Murine DSS Colitis and TNFΔARE Ileitis
Authors: Verstockt B , Hanley M , Nakanishi M , Rosenberg D , Parkinson J , Mathias G , de Zoeten E 
Published: January 2025

Abstract

Background
Resolvin E1 (RvE1) and leukotriene B4 (LTB4) are both BLT1 receptor agonists but elicit distinct biological outcomes through biased agonism. LTB4, a pro-inflammatory lipid mediator, initiates and regulates inflammatory responses by stimulating recruitment and activation of immune cells. In contrast, RvE1, a pro-resolution lipid mediator, selectively engages BLT1 to promote immune homeostasis and repair. TP-317, a stabilized RvE1 molecule, is being investigated as an oral therapy for inflammatory bowel disease (IBD). The subject studies describe the efficacy and mechanism of TP-317 in two preclinical colitis models.

Methods
DSS colitis: 8-wk old C57Bl6/J mice (n=12/group) were given two 5-day cycles of DSS (1%, 2%) separated by a 10-day recovery period, followed by 7 days of daily oral treatment starting on day 20 with TP-317 (0.04, 0.4 or 4 mg/kg), cyclosporin (25 mg/kg), the JAK1 inhibitor filgotinib (36 mg/kg), or vehicle. Colitis symptoms were scored daily using disease activity index (DAI). Mice were sacrificed on day 27 for histology. TNFΔARE Ileitis:8-10 wk old TNFΔARE mice were treated with daily oral TP-317 at 0.04, 0.4 and 4 mg/kg for 14 days (n=3/group). On Day 13, mice were administered FITC-Dextran (0.4 g/kg/d) by oral gavage and blood drawn after 4 hrs to measure intestinal permeability. Animals were sacrificed on day 14, intestinal tissue was harvested and cytokine levels were measured in whole tissue lysates by ELISA; disease activity was scored by histology.

Results
In DSS colitis, 0.4 mg/kg TP-317 showed similar efficacy to cyclosprin and filgotinib in reducing DAI scores. Overall histology scores (a composite of inflammation severity, inflammation depth and crypt loss) were reduced by 14% (NS), 22% (NS) and 33% (p&lt;0.01) by 0.04, 0.4 and 4 mg/kg TP-317, respectively, compared to 33% (p&lt;0.01) for cyclosporin and 44% (p&lt;0.001) for filgotinib. All doses of TP-317 significantly reduced Crypt Damage score (34%, 37%, 39%), showing greater effects than cyclosporin or filgotinib. In TNFΔARE ileitis, TP-317 treatment was associated with reduced intestinal permeability and disease activity, while reducing pro- inflammatory IL-17 and increasing anti-inflammatory L-10 in mucosal tissue.

Conclusion
Oral TP-317 demonstrates anti-inflammatory, mucosal immuno-modulatory and epithelial barrier protective actions in preclinical colitis and ileitis. These findings align with reports of have exacerbated DSS colitis in BLT1-/- mice and RvE1’s promotion of BLT1-dependent wound repair in an in vitro model using human intestinal epithelial cells.1 2 Together, these studies support positioning of TP-317 as a novel, oral BLT1 agonist for treating ileal and colonic disease in IBD patients.

References
1 Jala VR, Maturu P, Bodduluri SR, Krishnan E, Mathis S, Subbarao K, Wang M, Jenson AB, Proctor ML, Rouchka EC, Knight R, Haribabu B. Leukotriene B4-receptor-1 mediated host response shapes gut microbiota and controls colon tumor progression. Oncoimmunology. 2017 Aug 10;6(12):e1361593. PMID 29209564
2 Hayashi S, Muraleedharan CK, Oku M, Tomar S, Hogan SP, Quiros M, Parkos CA, Nusrat A. Intestinal epithelial BLT1 promotes mucosal repair. JCI Insight. 2022 Dec 8;7(23):e162392. PMID 36301666