Development of Apoptotic-Cell-Inspired Antibody-Drug Conjugate for Effective Immune Modulation.

BACKGROUND: Apoptotic cells' phosphoserine (PS) groups have a significant immunosuppressive effect. They inhibit proinflammatory signals by interacting with various immune cells, including macrophages, dendritic cells, and CD4+ cells. Previously, we synthesized PS-group-immobilized polymers and verified their immunomodulatory effects. Despite its confirmed immunomodulatory potential, the PS group has not been considered as a payload for antibody-drug conjugates (ADCs) in a targeted anti-inflammatory approach. AIM: We conducted this research to introduce an apoptotic-cell-inspired antibody-drug conjugate for effective immunomodulation. METHOD: Poly(2-hydroxyethyl methacrylate-co-2-methacryloyloxyethyl phosphorylserine) (p(HEMA-co-MPS)) was synthesized as a payload using RAFT polymerization, and goat anti-mouse IgG was selected as a model antibody, which was conjugated with the synthesized p(HEMA-co-MPS) via 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-Hydroxysuccinimide (EDC/NHS) reaction. The antibody-binding affinity, anti-inflammatory potential, and cytotoxicity measurements were evaluated. RESULTS: We successfully synthesized ADCs with a significant anti-inflammatory effect and optimized the antibody-polymer ratio to achieve the highest antibody-binding affinity. CONCLUSION: We successfully introduced p(HEMA-co-MPS) to IgG without decreasing the anti-inflammatory potential of the polymer while maintaining its targeting ability. We suggest that the antibody-polymer ratio be appropriately adjusted for effective therapy. In the future, this technology can be applied to therapeutic antibodies, such as Tocilizumab or Abatacept.

Design of an apoptotic cell-mimetic wound dressing using phosphoserine-chitosan hydrogels.

Inflammatory M1 macrophages create a hostile environment that impedes wound healing. Phosphoserine (PS) is a naturally occurring immunosuppressive molecule capable of polarizing macrophages from an inflammatory phenotype (M1) to an anti-inflammatory phenotype (M2). In this study, we designed, fabricated, and characterized PS-immobilized chitosan hydrogels as potential wound dressing materials. A PS group precursor was synthesized via a phosphoramidite reaction and subsequently immobilized onto the chitosan chain through an EDC/N-hydroxysuccinimide reaction using a crosslink moiety HPA. The PS/HPA-conjugated chitosan (CS-PS) was successfully synthesized by deprotecting the PS group in HCl. In addition, the hydrogels were prepared by the HRP/H2O2 enzyme-catalyzed reaction with different PS group contents (0, 7.27, 44.28 and 56.88 µmol g-1). The immobilization of the PS group improved the hydrophilicity of the hydrogels. Interestingly, CS-PS hydrogel treatment upregulated both pro-inflammatory and anti-inflammatory cytokines. This treatment also resulted in alterations in the macrophage cell morphology from the M1 to M2 phenotype. The CS-PS hydrogel significantly accelerated diabetic wound healing. Overall, this study provides insights into the potential of PS-immobilized hydrogel materials for improved inflammatory disease therapy.

Green tea catechin-grafted silk fibroin hydrogels with reactive oxygen species scavenging activity for wound healing applications.

BACKGROUND: Overproduction of reactive oxygen species (ROS) is known to delay wound healing by causing oxidative tissue damage and inflammation. The green tea catechin, (-)-Epigallocatechin-3-O-gallate (EGCG), has drawn a great deal of interest due to its strong ROS scavenging and anti-inflammatory activities. In this study, we developed EGCG-grafted silk fibroin hydrogels as a potential wound dressing material. METHODS: The introduction of EGCG to water-soluble silk fibroin (SF-WS) was accomplished by the nucleophilic addition reaction between lysine residues in silk proteins and EGCG quinone at mild basic pH. The resulting SF-EGCG conjugate was co-crosslinked with tyramine-substituted SF (SF-T) via horseradish peroxidase (HRP)/H2O2 mediated enzymatic reaction to form SF-T/SF-EGCG hydrogels with series of composition ratios. RESULTS: Interestingly, SF-T70/SF-EGCG30 hydrogels exhibited rapid in situ gelation (< 30 s), similar storage modulus to human skin (≈ 1000 Pa) and superior wound healing performance over SF-T hydrogels and a commercial DuoDERM® gel dressings in a rat model of full thickness skin defect. CONCLUSION: This study will provide useful insights into a rational design of ROS scavenging biomaterials for wound healing applications.