Name: Isolation of Synovial Macrophages
Uploaded: 2023-02-24T13:30:00
Description: Watch this Scientific Journal Video about Isolation of Synovial Macrophages at JoVE.com

isolation of synovial macrophages

Revelando a artrite inflamatória: explorando as funções das células sinoviais

Rheumatoid arthritis (RA) is an autoimmune disease characterized by hyperplasia of the synovium, leading to joint destruction1,2. Tissue-resident macrophages and fibroblasts are present in healthy synovium to maintain joint homeostasis. In RA patients, synovial fibroblasts (SFs) proliferate, and immune cells, including monocytes, infiltrate into the synovium and joint fluid, processes associated with inflammation1,3,4. Synovial macrophages (SMs), which include resident macrophages and peripheral blood monocyte-derived macrophages, and SFs are aberrantly activated and have important roles in RA pathogenesis. Recent studies have suggested that cell-cell interactions between SMs and SFs contributes to both the exacerbation and remission of RA5,6. 
To understand RA pathogenesis, several rodent models of inflammatory arthritis have been used, including K/BxN serum transfer arthritis, collagen-induced arthritis, and collagen antibody-induced arthritis. Cell-based assays are generally required to clarify molecular functions in arthritis. Therefore, primary cells from animal models of arthritis have been isolated. The method to isolate SFs from murine arthritis tissue is well established, and these cells have contributed to the elucidation of molecular mechanisms in arthritis pathogenesis7,8. On the other hand, bone marrow-derived macrophages, blood monocyte-derived macrophages, and macrophage cell lines have often been used as macrophage resources for arthritis studies9,10. Since macrophages can acquire functions associated with their microenvironment, general sources of macrophages may lack responses specific to arthritis tissue. In addition, it is difficult to obtain enough synovial cells by sorting, as murine synovium is a very small tissue even in arthritis models. The lack of usage of synovial macrophages for in vitro studies has been a limitation in arthritis studies. The establishment of a protocol to isolate and expand synovial macrophages would be an advantage for the elucidation of pathological mechanisms in RA.
In the previous method to isolate SFs, SMs were discarded7. Besides that, a method to isolate and expand resident macrophages from some organs was reported11. Therefore, existing protocols were modified in combination. The modification aims to achieve the primary culture of both SMs and SFs with high purity. The overall goal of this method is to isolate and expand both SMs and SFs from murine arthritis tissue.

Autor em destaque: Isolamento e cultura de macrófagos sinoviais primários e fibroblastos de tecido de artrite murina  

Isolamento e Cultura de Macrófagos e Fibroblastos Sinoviais Primários de Tecido de Artrite Murina

Cell-based assays are required to clarify molecular functions. In arthritis studies, the method to isolate primary cells is well established in synovial fibroblasts, but not in synovial macrophages. Therefore, we developed a protocol to isolate and expand both synovial macrophages and synovial fibroblasts from arthritis models.Primary synovial fibroblasts from murine arthritis tissue have contributed to the elucidation of molecular mechanisms in arthritis pathogenesis. On the other hand, bone marrow-derived macrophages, blood monocyte-derived macrophages, and macrophage cell lines have often been used as macrophage resources for arthritis studies. Since macrophages can acquire functions associated with their microenvironment, general sources of macrophages may lack responses specific to arthritis tissue.In addition, it is difficult to obtain enough synovial cells by sorting, as murine synovium is a very small tissue even in arthritis models. In the previous method to isolate synovial fibroblasts, synovial macrophages were discarded. Besides that, a method to isolate and expand resident macrophages from some organs was reported.Therefore, existing protocols were modified in combination to isolate and expand both synovial macrophages and synovial fibroblasts from murine arthritis tissue. This method can isolate both macrophages and fibroblasts from inflammatory synovium with high purity, and it is simple and reproducible. This method allows the expansion of synovial macrophages under co-culture with synovial fibroblasts.Also, the method provides an advantage, in that synovial fibroblasts can be used with fewer passages. The established protocol would be an advantage for elucidation of pathological mechanisms in rheumatoid arthritis.

Watch this Scientific Journal Video about Isolation of Synovial Macrophages at JoVE.com

Isolation of Synovial Macrophages  

Isolamento de Macrófagos Sinoviais

Antes de iniciar, realizar o isolamento dos fibroblastos sinoviais e utilizar as células não aderentes coletadas da placa revestida com colágeno neste procedimento. Seme as células não aderentes em placas de 40 a 60 milímetros que não tenham sido revestidas com colágeno. Cultivar as células a granel por um dia a 37 graus Celsius em uma atmosfera umidificada com 5% de dióxido de carbono.Para remover linfócitos não aderentes, aspirar o meio de cultura e, em seguida, adicionar meio de cultura fresco. Cultivar as células a granel aderentes por uma a duas semanas com trocas de meio a cada dois dias, mantendo a confluência. Em seguida, lave duas vezes com PBS ou HBSS.Selecionar macrófagos sinoviais tratando com 0,05% de tripsina em HBSS e incubar por três minutos a 37 graus Celsius em uma atmosfera umidificada com dióxido de carbono a 5%. Em seguida, adicione o meio de cultura suavemente a 0,05% de tripsina em HBSS. Após esta etapa, não despeje o meio diretamente sobre as células.Para remover as células destacadas, aspirar o meio de cultura e, em seguida, adicionar o meio de cultura fresco suavemente. Repetir duas ou três vezes e manter as células na placa em meio de cultura fresco até o uso. Células semelhantes a macrófagos foram isoladas de camundongos C57BL/6 fêmeas com sete a oito semanas de idade e analisadas por RT-qPCR.A expressão de RNAm dos marcadores pan-macrófagos CD68, EMR1, ITGAM, CSF1R mostrou um isolamento rico em macrófagos do tecido da sinovite. Para estabelecer a pureza dos macrófagos, marcadores proteicos de superfície para macrófagos e outros tipos celulares foram analisados por citometria de fluxo. Mais de 90% das células expressaram marcadores de macrófagos CD45, CD11b e F4/80, enquanto a expressão do marcador de neutrófilos Ly6G e do marcador de células T CD3 foi menor que 1%

Research

JoVE Journal

Biology

Isolation of Synovial Macrophages

Isolation and Culture of Primary Synovial Macrophages and Fibroblasts from Murine Arthritis Tissue

Rheumatoid arthritis is an autoimmune disease that leads to chronic inflammation of joints. Synovial macrophages and synovial fibroblasts have central roles in the pathogenesis of rheumatoid arthritis. It is important to understand the functions of both cell populations to reveal the mechanisms underlying pathological progression and remission in inflammatory arthritis. In general, in vitro experimental conditions should mimic the in vivo environment as much as possible. Primary tissue-derived cells have been used in experiments characterizing synovial fibroblasts in arthritis. In contrast, in experiments investigating the biological functions of macrophages in inflammatory arthritis, cell lines, bone marrow-derived macrophages, and blood monocyte-derived macrophages have been used. However, it is unclear whether such macrophages actually reflect the functions of tissue-resident macrophages. To obtain resident macrophages, previous protocols were modified to isolate and expand both primary macrophages and fibroblasts from synovial tissue in an inflammatory arthritis mouse model. These primary synovial cells may be useful for in vitro analysis of inflammatory arthritis.

The present study provides a modified protocol to isolate synovial macrophages and fibroblasts from murine inflammatory arthritis tissue.

Rheumatoid arthritis is an autoimmune disease that leads to chronic inflammation of joints. Synovial macrophages and synovial fibroblasts have central ...

Biologia

Digestion of Synovitis Tissue

Begin by placing the dissected mouse knee joints in a culture dish. Aspirate the culture medium and add fresh culture medium. Repeat the washing three or four times.Then under a stereo microscope, dislocate all the joints in the culture medium by pulling them using fine point tweezers. Remove the tibia and as many vessels, tendons, and ligaments as possible, being careful not to break the bones. Prepare two 15 milliliter tubes per sample.Using tweezers, transfer the dislocated bones with soft tissues to the first tube. For each sample obtained from both hind paws add four milliliters of digestion medium to the tube. To collect residual cells and tissue fragments transfer the culture medium from the dissection dish to the second 15 milliliter tube.Centrifuge the medium at 500 G for 5 minutes at room temperature. After removing the supernatant, resuspend the pellet with one milliliter of digestion medium. And transfer this solution to the first 15 milliliter tube so that it contains almost all the tissue, in total five milliliters of digestion medium.Then digest the sample for 60 to 120 minutes at 37 degrees Celsius with shaking in a hybridization oven. After incubation, mix the sample by pipetting and filter the cell solution through a 40 micron cell strainer into a 50 milliliter tube. Add 10 milliliters of culture medium to the tube through the cell strainer.Centrifuge at 300 G for 5 minutes at room temperature. Remove the supernatant and resuspend the cell pellet with 10 milliliters of culture medium. Repeat the centrifugation, discard the supernatant, and resuspend the pellet with two milliliters of culture medium.

Digestão do tecido de sinovite

Isolation of Synovial Fibroblasts

Use the cell suspensions obtained after digestion of mouse knee joints, and seed the suspension on the collagen-coated dish. Incubate the dish for one hour at 37 degrees Celsius in a humidified atmosphere with 5%carbon dioxide. After incubation, collect non-adherent cells using a pipette.Wash the collagen coated dish with culture medium, and collect the medium. Then, add fresh medium to the dish to culture the adherent cells that exhibit a fibroblastoid morphology. Treat the cells with 0.05%trypsin in Hank's balanced salt solution, and passage the sub confluent cells.If highly pure fibroblast-like cells are required, perform repeated passaging. Ensure to use cells with less than five passages. Fibroblast-like cells were isolated from inflammatory arthritis tissue, induced in seven to eight weeks old female C57BL/6 mice.The purity of the isolated cells was assessed by RTQPCR mRNA expression of synovial fibroblast markers, such as Vcam1, Cdh11, Col6a1, and Csf1 in the isolated cells suggested that the fibroblast-rich fractions were isolated from synovitis tissue.

Isolamento de fibroblastos sinoviais

Before beginning, perform synovial fibroblast isolation and use the non-adherent cells collected from the collagen-coated dish in this procedure. Seed the non-adherent cells on 40 to 60 millimeter dishes that have not been coated with collagen. Culture the bulk cells for one day at 37 degrees Celsius in a humidified atmosphere with 5%carbon dioxide.To remove non-adherent lymphocytes, aspirate the cultured medium and then add fresh culture medium. Culture the adherent bulk cells for one to two weeks with medium changes every two days, while maintaining confluence. Then wash two times with PBS or HBSS.Select for synovial macrophages by treating with 0.05%trypsin in HBSS and incubate for three minutes at 37 degrees Celsius in a humidified atmosphere with 5%carbon dioxide. Then add culture medium gently to 0.05%trypsin in HBSS. After this step, do not pour the medium directly onto the cells.To remove detached cells, aspirate the cultured medium and then add fresh culture medium gently. Repeat two or three times and maintain the cells on the dish in fresh culture medium until use. Macrophage-like cells were isolated from seven to eight weeks old female C57BL/6 mice and analyzed by RT-qPCR.mRNA expression of pan-macrophage markers CD68, EMR1, ITGAM, CSF1R showed macrophage rich isolation from the synovitis tissue. To establish the purity of macrophages, surface protein markers for macrophages and other cell types were analyzed by flow cytometry. More than 90%of the cells expressed macrophage markers CD45, CD11b and F4/80, whereas the expression of neutrophil marker Ly6G and T-cell marker CD3 was lower than 1%