α-GalCer sp2-iminoglycolipid analogs as CD1d-dependent iNKT modulators: Evaluation of their immunotherapeutic potential in murine models of asthma and autoimmune hepatitis

Alan Chuan-Ying Lai; Manuel González-Cuesta; Chieh-Hsin Ho; Po-Yu Chi; Ko-Chien Wu; Gabriel Rocha; Juan C Muñoz-García; Jesús Angulo; José M García Fernández; Ya-Jen Chang; Carmen Ortiz Mellet

doi:10.1016/j.ejmech.2024.117060

α-GalCer sp²-iminoglycolipid analogs as CD1d-dependent iNKT modulators: Evaluation of their immunotherapeutic potential in murine models of asthma and autoimmune hepatitis

Eur J Med Chem. 2024 Nov 15:282:117060. doi: 10.1016/j.ejmech.2024.117060. Online ahead of print.

Affiliations

¹ Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, 115, Taiwan.
² Department of Organic Chemistry, Faculty of Chemistry, University of Seville, E-41012, Seville, Spain.
³ Instituto de Investigaciones Químicas (IIQ), CSIC - Universidad de Sevilla, Avda. Américo Vespucio 49, E-41092, Sevilla, Spain.
⁴ Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, 115, Taiwan; Institute of Microbiology and Immunology, National Defense University, Taipei, 114, Taiwan; Institute of Translational Medicine and New Drug Development, China Medical University, Taichung, 404, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 807, Taiwan. Electronic address: yajchang@ibms.sinica.edu.tw.
⁵ Department of Organic Chemistry, Faculty of Chemistry, University of Seville, E-41012, Seville, Spain. Electronic address: mellet@us.es.

PMID: 39561498
DOI: 10.1016/j.ejmech.2024.117060

Abstract

Invariant natural killer T (iNKT) cells are a subset of innate T cells displaying powerful immunomodulatory functions. Despite extensive preclinical research on the use of iNKT agonist and antagonist for various diseases, translating these findings into successful clinical applications has proven challenging, leaving no approved treatments to date. Efforts to optimize therapeutic outcomes by developing alternative glycolipids to α-galactosylceramide (α-GalCer or KRN7000), the prototypical iNKT antigen, have shown improved preclinical results. However, significant obstacles remain, including the relatively laborious synthesis of α-glycosides and their vulnerability to degradation by α-glycosidases. To overcome these limitations, we explored the use of sp²-iminosugars, a class of glycomimetics, to replace the carbohydrate moiety in α-GalCer-like glycolipids. This substitution offers enhanced biostability and precise control over α-selectivity in glycosylation reactions. The resulting sp²-iminoglycolipids (sp²-IGLs) were tested for their immunomodulatory effects, demonstrating the ability to bind the α-GalCer binding site on the CD1d protein in antigen-presenting cells (APCs), and functioning as iNKT antagonists in α-GalCer-stimulated splenocytes. Notably, analogs featuring a 4-alkyl-1,2,3-aminotriazol-1-yl segment in place of the C₂₅N-acyl tail in α-GalCer additionally exhibited mild agonistic activity in the absence of α-GalCer stimulation. Computational studies support the formation of stable CD1d- sp²-IGL and CD1d - sp²-IGL - T-cell receptor complexes, with significant differences in the dynamics depending on the glycone nature and lipid tail length. These findings provide a molecular rationale for the observed experimental data. Furthermore, in vivo studies using murine models of asthma and autoimmune hepatitis have identified promising sp²-IGL candidates for further development in immunotherapy.

Keywords: Asthma; Autoimmune hepatitis; Glycolipids; Immunomodulation; Natural killer T cells; sp(2)-iminosugars; α-galactosylceramide.