Journal Article

Deficiency of the pattern-recognition receptor CD14 protects against joint pathology and functional decline in a murine model of osteoarthritis

Zhou, Cheng, Dodge, George R., Nguyen, Vu, Smalley, Ryan, Scanzello, Carla R., Sambamurthy, Nisha, Hankenson, Kurt D.

2018

Overview

CD14 is a monocyte/macrophage pattern-recognition receptor that modulates innate inflammatory signaling. Soluble CD14 levels in knee OA synovial fluids are associated with symptoms and progression of disease. Here we investigate the role of this receptor in development of OA using a murine joint injury model of disease. 10-week-old Male C57BL/6 (WT) and CD14-deficient (CD14-/-) mice underwent destabilization of the medial meniscus (DMM) surgery to induce OA. Joint histopathology was used to examine cartilage damage, and microCT to evaluate subchondral bone (SCB) remodeling at 6 and 19 weeks after surgery. Synovial and fat pad expression of macrophage markers (F4/80, CD11c, CD68, iNOS, CCR7, CD163 and CD206) was assessed by flow cytometry and droplet digital (dd)PCR. Changes in locomotive activity indicative of joint pain were evaluated longitudinally up to 16 weeks by automated behavioral analysis. Early cartilage damage scores 6 weeks post-DMM were similar in both strains (Mean score ±SEM WT: 4.667±1.38, CD14-/-: 4.6±0.6), but at 19 weeks were less severe in CD14-/- (6.0±0.46) than in WT mice (13.44±2.5, p = 0.0002). CD14-/- mice were protected from both age-related and post-surgical changes in SCB mineral density and trabecular thickness. In addition, CD14-/- mice were protected from decreases in climbing activity (p = 0.015 vs. WT, 8 weeks) observed after DMM. Changes in synovial/fat pad expression of CCR7, a marker of M1 macrophages, were slightly reduced post-DMM in the absence of CD14, while expression of CD68 (pan-macrophage marker) and CD163 (M2 marker) were unchanged. CD14 plays an important role in progression of structural and functional features of OA in the DMM model, and may provide a new target for therapeutic development.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Age / Animal models / Animals / Arthralgia / Arthritis / Biocompatibility / Biology and Life Sciences / Bone remodeling / Bone surgery / Cartilage / Cartilage - pathology / Cartilage diseases / CC chemokine receptors / CCR7 protein / CD11c antigen / CD14 antigen / CD163 antigen / Computational fluid dynamics / Computed tomography / Damage assessment / Destabilization / Disease Models, Animal / Flow cytometry / Gene Expression Regulation / Histochemistry / Histopathology / House mouse / Inflammation / Joints - diagnostic imaging / Joints - pathology / Joints - physiopathology / Joints - surgery / Knee / Lipopolysaccharide Receptors - deficiency / Lipopolysaccharide Receptors - metabolism / Locomotive industry / Locomotives / Macrophages / Macrophages - metabolism / Macrophages - pathology / Male / Medical research / Medicine / Medicine and Health Sciences / Menisci, Tibial - pathology / Menisci, Tibial - physiopathology / Meniscus / Mice / Mice, Inbred C57BL / Monocytes / Nitric-oxide synthase / Orthopedics / Osteoarthritis / Osteoarthritis - diagnostic imaging / Osteoarthritis - metabolism / Osteoarthritis - pathology / Osteoarthritis - surgery / Pain / Pathology / Pattern recognition / Pattern recognition receptors / Proteins / Receptors, Pattern Recognition - deficiency / Receptors, Pattern Recognition - metabolism / Rheumatology / Risk factors / RNA, Messenger - genetics / RNA, Messenger - metabolism / Stem cells / Structure-function relationships / Subchondral bone / Surgery / Veterans / X-Ray Microtomography