Department for Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
J Cell Mol Med. 2011 Apr;15(4):756-62. doi: 10.1111/j.1582-4934.2010.01051.x.
Microparticles (MPs) are small membrane-vesicles that accumulate in the synovial fluids of patients with rheumatoid arthritis (RA). In the arthritic joints, MPs induce a pro-inflammatory and invasive phenotype in synovial fibroblasts (SFs). The present study investigated whether activation of SFs by MPs stimulates angiogenesis in the inflamed joints of patients with RA. MPs were isolated from Jurkat cells and U937 cells by differential centrifugation. SFs were co-cultured with increasing numbers of MPs. The effects of supernatants from co-cultures on endothelial cells were studied in vitro and in vivo using MTT assays, annexin V and propidium iodide staining, trans-well migration assays and modified matrigel pouch assays. MPs strongly induced the expression of the pro-angiogenic ELR⁺ chemokines CXCL1, CXCL2, CXCL3, CXCL5 and CXCL6 in RASFs. Other vascular growth factors were not induced. Supernatants from co-cultures enhanced the migration of endothelial cells, which could be blocked by neutralizing antibodies against ELR⁺ chemokines. Consistent with the specific induction of ELR⁺ chemokines, proliferation and viability of endothelial cells were not affected by the supernatants. In the in vivo bio-chamber assay, supernatants from RASFs co-cultured with MPs stimulated angiogenesis with a significant increase of vessels infiltrating into the matrigel chamber. We demonstrated that MPs activate RASFs to release pro-angiogenic ELR⁺ chemokines. These pro-angiogenic mediators enhance migration of endothelial cells and stimulate the formation of new vessels. Our data suggest that MPs may contribute to the hypervascularization of inflamed joints in patients with rheumatoid arthritis.
微粒（MPs）是在类风湿关节炎（RA）患者的滑液中积累的小膜囊泡。在关节炎关节中， MPs 诱导滑膜成纤维细胞（SFs）产生促炎和侵袭表型。本研究调查了 MPs 对 SFs 的激活是否刺激 RA 患者炎症关节中的血管生成。通过差速离心从 Jurkat 细胞和 U937 细胞中分离 MPs。将 SFs 与数量不断增加的 MPs 共培养。使用 MTT 测定法、膜联蛋白 V 和碘化丙啶染色、Transwell 迁移测定法和改良的 Matrigel 小袋测定法，在体外和体内研究共培养物上清液对内皮细胞的影响。 MPs 强烈诱导 RASFs 中促血管生成的 ELR⁺趋化因子 CXCL1、CXCL2、CXCL3、CXCL5 和 CXCL6 的表达。其他血管生长因子未被诱导。共培养物的上清液增强了内皮细胞的迁移，这可以被针对 ELR⁺趋化因子的中和抗体阻断。与 ELR⁺趋化因子的特异性诱导一致，内皮细胞的增殖和活力不受上清液的影响。在体内生物室测定中，与 MPs 共培养的 RASFs 的上清液刺激血管生成，导致大量血管渗透到 Matrigel 室中。我们证明 MPs 激活 RASFs 释放促血管生成的 ELR⁺趋化因子。这些促血管生成介质增强了内皮细胞的迁移并刺激了新血管的形成。我们的数据表明， MPs 可能有助于类风湿关节炎患者炎症关节的过度血管化。
