Clinical and Translational Medicine | 2021
NAV2 positively modulates inflammatory response of fibroblast‐like synoviocytes through activating Wnt/β‐catenin signaling pathway in rheumatoid arthritis
Abstract
Dear Editor, Rheumatoid arthritis (RA) is a common chronic autoimmune disease that causes progressive joint destruction and involves severe damage to physical function and life quality.1 Without rational drug intervention, 80% patients will become incapable of mobility after 3 years of illness.2 In the pathogenesis of RA, activated fibroblast-like synoviocytes (FLS) participate in the inflammatory process of RA through their own proliferation, migration, and invasion.3,4 However, despite the thorough research, there are still gaps in our understanding of RA pathogenesis. Therefore, it is important to better understand the etiopathogenesis of RA. Neuron navigator 2 (NAV2) belongs to the neuron navigator family which mainly regulates growth, migration, and regeneration of neurons in the nervous system and is highly expressed in the brain, kidney, liver, and also existed in the skeleton, heart, placenta, as well as abundantly elevated in colon cancers.5 Previous studies have found that NAV2 facilitates invasion of cutaneous melanoma cells and plays a vital role in the poor prognosis of melanoma patients.6 Also, in the results of proteomics, NAV2 is abnormally highly expressed in RA patients’ primary FLS compared with healthy volunteers.7 However, the specific role of NAV2 in RA remains unknown. We first examined NAV2 protein level in blood samples and found a significant increase of NAV2 expression in RA patients compared with osteoarthritis (OA) patients or healthy samples (Figure 1A). The clinically relevant information and spreadsheet are shown in Table S1. Then we performed an immunofluorescence doublestaining experiment. The expression of vimentin indicated that the cells derived from synovium tissues were primary FLS and NAV2 expression was significantly upregulated (Figure 1B). Moreover, we confirmed the significant elevation of NAV2 in the primary RA synovial cells by using RT-qPCR and Western blot analysis