Morphofunctional analysis of fibroblast-like synoviocytes in human rheumatoid arthritis and mouse collagen-induced arthritis.

BACKGROUND: Fibroblast-like synoviocytes (FLS) play a prominent role in rheumatoid synovitis and degradation of the extracellular matrix through the production of inflammatory cytokines and metalloproteinases (MMPs). Since animal models are frequently used for elucidating the disease mechanism and therapeutic development, it is relevant to study the ultrastructural characteristics and functional responses in human and mouse FLS. The objective of the study was to analyze ultrastructural characteristics, Interleukin-6 (IL-6) and Metalloproteinase-3 (MMP-3) production and the activation of intracellular pathways in Fibroblast like synoviocytes (FLS) cultures obtained from patients with rheumatoid arthritis (RA) and from mice with collagen-induced arthritis (CIA). METHODS: FLSs were obtained from RA patients (RA-FLSs) (n = 8) and mice with CIA (CIA-FLSs) (n = 4). Morphology was assessed by transmission and scanning electron microscopy. IL-6 and MMP-3 production was measured by ELISA, and activation of intracellular signaling pathways (NF-κB and MAPK: p-ERK1/2, p-P38 and p-JNK) was measured by Western blotting in cultures of RA-FLSs and CIA-FLSs stimulated with tumor necrosis factor-alpha (TNF-α) and IL-1ß. RESULTS: RA-FLS and CIA-FLS cultures exhibited rich cytoplasm, rough endoplasmic reticula and prominent and well-developed Golgi complexes. Transmission electron microscopy demonstrated the presence of lamellar bodies, which are cytoplasmic structures related to surfactant production, in FLSs from both sources. Increased levels of pinocytosis and numbers of pinocytotic vesicles were observed in RA-FLSs (p < 0.05). Basal production of MMP-3 and IL-6 was present in RA-FLSs and CIA-FLSs. Regarding the production of MMP-3 and IL-6 and the activation of signaling pathways, the present study demonstrated a lower response to IL-1ß by CIA-FLSs than by RA-FLSs. CONCLUSION: This study provides a comprehensive understanding of the biology of RA-FLS and CIA-FLS. The differences and similarities in ultrastructural morphology and important inflammatory cytokines shown, contribute to future in vitro studies using RA-FLS and CIA-FLS, in addition, they indicate that the adoption of CIA-FLS for studies should take careful and be well designed, since they do not completely resemble human diseases.

Morphofunctional analysis of fibroblast-like synoviocytes in human rheumatoid arthritis and mouse collagen-induced arthritis

Abstract Background Fibroblast-like synoviocytes (FLS) play a prominent role in rheumatoid synovitis and degradation of the extracellular matrix through the production of inflammatory cytokines and metalloproteinases (MMPs). Since animal models are frequently used for elucidating the disease mechanism and therapeutic development, it is relevant to study the ultrastructural characteristics and functional responses in human and mouse FLS. The objective of the study was to analyze ultrastructural characteristics, Interleukin-6 (IL-6) and Metalloproteinase-3 (MMP-3) production and the activation of intracellular pathways in Fibroblast like synoviocytes (FLS) cultures obtained from patients with rheumatoid arthritis (RA) and from mice with collagen-induced arthritis (CIA). Methods FLSs were obtained from RA patients (RA-FLSs) (n = 8) and mice with CIA (CIA-FLSs) (n = 4). Morphology was assessed by transmission and scanning electron microscopy. IL-6 and MMP-3 production was measured by ELISA, and activation of intracellular signaling pathways (NF-κB and MAPK: p-ERK1/2, p-P38 and p-JNK) was measured by Western blotting in cultures of RA-FLSs and CIA-FLSs stimulated with tumor necrosis factor-alpha (TNF-α) and IL-1β. Results RA-FLS and CIA-FLS cultures exhibited rich cytoplasm, rough endoplasmic reticula and prominent and well- developed Golgi complexes. Transmission electron microscopy demonstrated the presence of lamellar bodies, which are cytoplasmic structures related to surfactant production, in FLSs from both sources. Increased levels of pinocytosis and numbers of pinocytotic vesicles were observed in RA-FLSs (p < 0.05). Basal production of MMP-3 and IL-6 was present in RA-FLSs and CIA-FLSs. Regarding the production of MMP-3 and IL-6 and the activation of signaling pathways, the present study demonstrated a lower response to IL-1β by CIA-FLSs than by RA-FLSs. Conclusion This study provides a comprehensive understanding of the biology of RA-FLS and CIA-FLS. The differences and similarities in ultrastructural morphology and important inflammatory cytokines shown, contribute to future in vitro studies using RA-FLS and CIA-FLS, in addition, they indicate that the adoption of CIA-FLS for studies should take careful and be well designed, since they do not completely resemble human diseases.

Desenvolvimento de artrite induzida por colágeno em camundongos DBA/1J entre os gêneros / Development of collagen-induced arthritis in DBA/1J mice between genders

Introdução: A artrite reumatoide (AR) é uma doença autoimune inflamatória sistêmica de etiologia desconhecida. Modelos animais de artrite são extremamente úteis para o estudo da fisiopatologia da doença e de novas terapias. Objetivo: Considerando a predominância da AR em mulheres e escassez de estudos sobre influência do sexo no desenvolvimento da artrite experimental, o objetivo deste trabalho foi avaliar o impacto do sexo no desenvolvimento clínico da artrite experimental induzida por colágeno do tipo II (CIA). Métodos: Camundongos DBA1J foram divididos em machos e fêmeas, ambos n=6. CIA foi induzida por duas injeções intradérmicas com colágeno no dia zero e 18. Escore clínico da artrite e do edema articular foram avaliados diariamente por 10 dias após o desenvolvimento da doença. Resultados: A evolução do escore clínico não demonstrou diferença entre os machos e fêmeas. O escore clínico avaliado separadamente - patas dianteiras e traseiras, apresentou diferença significativa (p<0,001) – patas traseiras dia 5 (machos 5,8±1,1; fêmeas 3,1±1,8 - p<0,05). Entretanto, o edema articular foi significativamente maior nos machos (p<0,001) no dia 5 (machos 4,5±0,4; fêmeas 3,8±0,5 - p<0,05). Conclusões: Apesar de não serem claras as diferenças entre machos e fêmeas na CIA em camundongos, a maioria dos pesquisadores da área optam por trabalhar com machos. Como em humanos, acredita-se na influência da genética e dos hormônios no desenvolvimento da CIA. Conclui-se que a diferença encontrada no desenvolvimento da artrite experimental entre machos e fêmeas é um parâmetro a ser avaliado de acordo com o tipo de estudo a ser realizado no modelo de CIA.

Background: Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease of unknown etiology. Animal models of arthritis are extremely useful to investigate the pathophysiology of the disease and its new therapies. Aim: Considering that RA affects predominantly women, and acknowledging the lack of studies about the influence of gender in the development of experimental arthritis, the objective of this study was to assess the impact of gender on the clinical development of type II collagen-induced arthritis (CIA). Methods: Animals were divided in two groups (male and female), both n = 6. CIA was induced using intradermal injections with collagen on day zero and 18. Clinical score of arthritis and joint edema were evaluated daily for 10 days after the onset of the disease. Results: Clinical score showed no difference between males and females. The clinical score assessed separately – front and rear paws, showed a significant difference (p<0.001) – rear paws on day 5 (males 5.8±1.1; females 3.1±1.8, p<0.05). However, joint edema was significantly larger (p<0.001) on day 5 (males 4.5±0.4; females 3.8±0.5; p<0.05). Conclusion: Although the differences between male and female mice with CIA are not clear, most researchers choose to work with males. Similarly to humans, genetics and hormones seem to have an influence on the development of CIA. In conclusion, the difference in the development of experimental arthritis between males and females should be assessed according to the type of study to be conducted using a CIA model.