NOD2-mediated monocyte/macrophage stimulation to enhance antibody therapies
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Date
2024-05
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Publisher
The Ohio State University
Abstract
Chronic lymphocytic leukemia (CLL) is a malignant disease where mature B cells accumulate in the blood, as well as in lymphoid organs. Over 20,000 new cases and nearly 4,500 deaths are expected in the United States alone for 2024. Monoclonal antibody therapies are used to treat CLL, among other diseases. Antibodies bind monocyte/macrophage Fcγ receptors (FcγRs), inducing phagocytosis and inflammatory cytokine release to promote clearance of target cells. However, monocytes and macrophages are suppressed by CLL cells. Toll-like receptor activation has improved therapeutic efficacy in vivo, with some ligands even clinically approved. Here, we investigated the potential of nucleotide-binding oligomerization domain-containing protein 2 (NOD2) in this capacity, for a NOD2 agonist is approved by the European Medicines Agency for osteosarcoma treatment. NOD2 is an intracellular pattern recognition receptor, which, upon binding muramyl dipeptide (MDP), induces inflammatory cytokine production via the NF-κB and MAPK pathways. Using healthy-donor monocytes as a model, we first used ELISA to confirm activation after L18-MDP treatment (MDP derivative), as measured by increased TNF-α release. Using qPCR, we then detected upregulation of the activating FcγRIIa, IIIa, and associated γ-chain. We subsequently confirmed protein-level increase in γ-chain expression by western blot. Investigating FcγR-mediated functions, while L18-MDP did not significantly increase antibody-mediated cytokine release, we detected significantly greater phagocytic activity after NOD2 stimulation and FcγR engagement. Finally, by applying pharmacological inhibitors, we discovered varying levels of involvement of NF-κB, MEK, and p38 in NOD2-mediated modulation of FcγR expression. In conclusion, this study suggests that NOD2 agonists may be considered as immunostimulatory agents for use in combination with monoclonal antibody therapies for diseases such as CLL.
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Keywords
NOD2, Antibody therapy, Fcγ receptors, Monocytes, Macrophages, Phagocytosis