A novel 3D spheroid model of rheumatoid arthritis synovial tissue incorporating fibroblasts, endothelial cells, and macrophages

Abstract

ObjectiveRheumatoid Arthritis (RA) is a progressive and systemic autoimmune disorder associated with chronic and destructive joint inflammation. The hallmarks of joint synovial inflammation are cellular proliferation, extensive neoangiogenesis and infiltration of immune cells, including macrophages. In vitro approaches simulating RA synovial tissue are crucial in preclinical and translational research to evaluate novel diagnostic and/or therapeutic markers. Two-dimensional (2D) settings present very limited in vivo physiological proximity as they cannot recapitulate cell-cell and cell-matrix interactions occurring in the three-dimensional (3D) tissue compartment. Here, we present the engineering of a spheroid-based model of RA synovial tissue which mimics 3D interactions between cells and pro-inflammatory mediators present in the inflamed synovium.MethodsSpheroids were generated by culturing RA fibroblast-like-synoviocytes (RAFLS), human umbilical vein endothelial cells (ECs) and monocyte-derived macrophages in a collagen-based 3D scaffold. The spheroids were cultured in the presence or absence of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (bFGF) or RA synovial fluid (SF). Spheroid expansion and cell migration were quantified for all conditions using confocal microscopy and digital image analysis.ResultsA novel approach using machine learning was developed to quantify spheroid outgrowth and used to reexamine the existing spheroid-based model of RA synovial angiogenesis consisting of ECs and RAFLS. A 2-fold increase in the spheroid outgrowth ratio was demonstrated upon VEGF/bFGF stimulation (p<0.05). The addition of macrophages within the spheroid structure (3.75x104 RAFLS, 7.5x104 ECs and 3.0x104 macrophages) resulted in good incorporation of the new cell type. The addition of VEGF/bFGF significantly induced spheroid outgrowth (p<0.05) in the new system. SF stimulation enhanced containment of macrophages within the spheroids.ConclusionWe present a novel spheroid based model consisting of RAFLS, ECs and macrophages that reflects the RA synovial tissue microenvironment. This model may be used to dissect the role of specific cell types in inflammatory responses in RA, to study specific signaling pathways involved in the disease pathogenesis and examine the effects of novel diagnostic (molecular imaging) and therapeutic compounds, including small molecule inhibitors and biologics.

Application of 3D bioprinting technology apply to assessing Dangguiniantongtang (DGNT) decoctions in arthritis

“…Although the application of 3D cell model to arthritis drug screening is in its early stages, several studies have researched their potential advantages. Researchers chose chondrocytes [ 47 – 50 ], synovial fibroblasts [ 51 ], RA fibroblast-like-synoviocytes [ 52 ] and vascular endothelial cells [ 51 ] as the research subjects in the constructed models, based on the pathological characteristics of different types of arthritis. Of particular interest is the fact that the vast majority of researchers chose to simulate the 3D state by culturing the cells in a hydrogel matrix without using 3D printing technology.…”

Emerging Landscape of In Vitro Models for Assessing Rheumatoid Arthritis Management

“…The fibroblasts and endothelial cells can be utilized to study synovial angiogenesis, NF-kB signaling, and its inhibitors. The primary synoviocytes, peripheral blood mononuclear cells, and mesenchymal stromal cells can be utilized to study the generation of de novo vascular structures during inflammation. , The scaffold model can utilize chondrocytes, and fibroblasts to study the cartilage damage, the role of genes and its expression in the disease pathogenesis. The pannus model can also be analyzed and the scaffold model also permits high throughput screening techniques.…”

A Review of Advances in Molecular Imaging of Rheumatoid Arthritis: From In Vitro to Clinic Applications Using Radiolabeled Targeting Vectors with Technetium-99m

“…In RA, inflammation of the synovium, called synovitis, leads to hyperplasia of the synovial lining and destruction of the cartilage and bones in the joints [ 11 , 12 , 13 ]. A healthy synovium consists of 1–2 linings of synoviocytes [ 14 , 15 , 16 ]. During inflammation, various mononuclear cells, such as T cells, B cells, dendritic cells, plasma cells, mast cells, and macrophages, infiltrate the site of inflammation ( Figure 1 ) [ 17 , 18 , 19 , 20 ]; the synovial lining becomes hyperplastic, resulting in expansion of the synovial membrane and the formation of villi [ 21 , 22 , 23 ].…”