Distinctive Immune Signatures Driven by Structural Alterations in Desmuramylpeptide NOD2 Agonists

Herein we report
on the design, synthesis and biological evaluation
of a series of nucleotide-binding oligomerization-domain-containing
protein 2 (NOD2) desmuramylpeptide agonists. The structural prerequisites
that shape both physicochemical and immunomodulatory profiles of desmuramylpeptide
NOD2 agonists have been delineated. Within this context, we identified 3, a butyrylated desmuramylpeptide, as a potent in
vitro NOD2 agonist (EC50 = 4.6 nM), exhibiting
an almost 17-fold enhancement in potency compared to its unsubstituted
counterpart 1 (EC50 = 77.0 nM). The novel
set of desmuramylpeptides demonstrate unique in vitro immunomodulatory activities. They elicited cytokine production in
peripheral blood mononuclear cells (PBMCs), both alone and in conjunction
with lipopolysaccharide (LPS). The spermine-decorated 32 also stimulated the LPS-induced cytotoxic activity (2.95-fold) of
PBMCs against K562 cancer cells. Notably, the cholesterol-conjugate 26 displayed anti-inflammatory actions, highlighted by its
capacity to convert the inflammatory monocyte subset into an anti-inflammatory
phenotype. Finally, the eicosapentaenoylated derivative 23 augmented antigen presentation by mouse bone marrow-derived dendritic
cells (BMDCs), thus highlighting its potential as a vaccine adjuvant.