Ion channel/Stat6-driven nano-immune programming of tissue-resident macrophages by amide-functionalized nanocellulose.

Abstract

Nanocellulose has long been studied as a bioactive material for tissue engineering; however, the mechanisms underlying its surface chemistry-mediated immune reprogramming remain unclear. Herein, we report a comprehensive multi-omics study of pristine cellulose nanocrystals (CNCs) and amide-functionalized CNCs (a-CNCs) to elucidate their '<i>nano-immune</i>' interaction and impact on tissue-resident macrophages <i>in vivo</i>. Using integrated scRNA-Seq, bulk RNA-Seq, pharmacological inhibition, and histological profiling, we reveal that a-CNCs exhibit outstanding biocompatibility, showing no pro-inflammatory activation of macrophages across major organs within 14-day subacute window. In particular, a-CNCs exposure correlates with enhanced voltage-gated ion channel (<i>KCa3.1</i> and <i>Scn1b</i>) and <i>Stat6</i> signaling, while suppressing <i>Nfkb</i>-driven pro-inflammatory signals. This suggest that ion channel activation is strongly associated with M2 macrophage polarization. Moreover, a 28-day splenocytes profiling revealed no observable increase in CD4⁺/CD8⁺ T cells, suggesting non-adaptive immune response after a-CNC exposure. Concurrently, pseudotime mapping further discloses that a-CNC exposure preserves natural macrophage developmental trajectories across organ niches, while pristine CNCs induce mild M1-skewing in the spleen. <i>In vitro</i> validation confirms that a-CNCs intrinsically drive a pro-healing phenotype in macrophages, underscoring that macro-scale immune behavior can be transcriptionally triggered through nano-level surface chemistry of CNCs.