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.