Journal Article

Nod2 Suppresses Borrelia burgdorferi Mediated Murine Lyme Arthritis and Carditis through the Induction of Tolerance

DeFrancesco, Alicia S., Hu, Linden T., Petnicki-Ocwieja, Tanja, Chung, Erin, Darcy, Courtney T., Bronson, Roderick T., Kobayashi, Koichi S.

2011

Overview

The internalization of Borrelia burgdorferi, the causative agent of Lyme disease, by phagocytes is essential for an effective activation of the immune response to this pathogen. The intracellular, cytosolic receptor Nod2 has been shown to play varying roles in either enhancing or attenuating inflammation in response to different infectious agents. We examined the role of Nod2 in responses to B. burgdorferi. In vitro stimulation of Nod2 deficient bone marrow derived macrophages (BMDM) resulted in decreased induction of multiple cytokines, interferons and interferon regulated genes compared with wild-type cells. However, B. burgdorferi infection of Nod2 deficient mice resulted in increased rather than decreased arthritis and carditis compared to control mice. We explored multiple potential mechanisms for the paradoxical response in in vivo versus in vitro systems and found that prolonged stimulation with a Nod2 ligand, muramyl dipeptide (MDP), resulted in tolerance to stimulation by B. burgdorferi. This tolerance was lost with stimulation of Nod2 deficient cells that cannot respond to MDP. Cytokine patterns in the tolerance model closely paralleled cytokine profiles in infected Nod2 deficient mice. We propose a model where Nod2 has an enhancing role in activating inflammation in early infection, but moderates inflammation after prolonged exposure to the organism through induction of tolerance.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Acute Disease / Animals / Antigens / Arachnids / Arthritis / Bacterial infections / Biological response modifiers / Biology / Bone marrow / Borrelia burgdorferi / Borrelia burgdorferi - immunology / Borrelia burgdorferi - physiology / Carditis / Caspase 1 - metabolism / Comparative analysis / Crohn's disease / Crohns disease / Cytokines / Epidermal growth factor / Health aspects / Immune response / Immune system / Immune Tolerance - genetics / Immune Tolerance - physiology / Immunological tolerance / Infection / Infections / Infectious diseases / Inflammation / Inflammation - complications / Inflammation - genetics / Inflammation Mediators - metabolism / Inflammatory bowel disease / Interferon / Internalization / Laboratory animals / Lyme disease / Lyme Disease - etiology / Lyme Disease - genetics / Lyme Disease - immunology / Lyme Disease - prevention & control / Lymphocytes B / Macrophages / Medicine / Mice / Mice, Inbred C57BL / Mice, Knockout / Muramyl dipeptide / Mutation / Myocarditis / Myocarditis - etiology / Myocarditis - genetics / Myocarditis - immunology / Myocarditis - prevention & control / NOD2 protein / Nod2 Signaling Adaptor Protein - genetics / Nod2 Signaling Adaptor Protein - metabolism / Nod2 Signaling Adaptor Protein - physiology / Phagocytes / Pneumonia / Stimulation / Tumor necrosis factor-TNF / Vector-borne diseases