SPECT Imaging of Joint Inflammation with Nanobodies Targeting the Macrophage Mannose Receptor in a Mouse Model for Rheumatoid Arthritis
SPECT Imaging of Joint Inflammation with Nanobodies Targeting the Macrophage Mannose Receptor in a Mouse Model for Rheumatoid Arthritis
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DOI：
10.2967/jnumed.112.111781
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发表时间：
2013-05-01
影响因子：
9.3
通讯作者：
Matthys, Patrick
中科院分区：
文献类型：
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作者：
Put, StePhanie;Schoonooghe, Steve;Matthys, Patrick
类风湿关节炎(RA)是一种慢性自身免疫性疾病，约占全球人口的1%。这种疾病主要影响关节，在那里，炎症细胞，如巨噬细胞，侵入滑膜，导致软骨和骨骼破坏。目前，对早期类风湿关节炎的有效诊断和监测较为困难。在这项研究中，我们研究了针对巨噬细胞甘露糖受体(MMR)的Tc-99m标记纳米抗体SPECT/Micro-CT成像是否可以用于监测和量化类风湿关节炎(RA)小鼠模型胶原诱导性关节炎(CIA)的关节炎症。分析MMR在体外培养的巨噬细胞和破骨细胞以及CIA小鼠不同器官细胞中的表达。方法：在完全弗氏佐剂中注射II型胶原诱导DBA/1小鼠CIA，取炎症关节和其他器官的细胞悬液。骨髓细胞在体外产生巨噬细胞和破骨细胞。采用定量聚合酶链式反应和流式细胞术检测MMR的表达。用99m标记的MMR和对照纳米体行SPECT/Micro-CT显像。结果：MMR在巨噬细胞上高表达，在体外培养的破骨细胞上表达较少。在CIA小鼠中，在骨髓、淋巴结和脾细胞上检测到MMR的表达。在关节滑液中，MMR表达于CD11b(+)F4/80(+)巨噬细胞。在连续注射MMR和对照纳米体的体内SPECT/Micro-CT成像中，在关节炎小鼠的膝盖、脚踝和脚趾处可以看到强烈的MMR信号。SPECT成像的量化证实了与对照纳米体相比，炎症关节中MMR信号的特异性。对爪子的解剖发现，在受影响的小鼠(即其他爪子出现关节炎症状的小鼠)的非关节炎爪子中，还有一个显著的MMR信号。结论：MMR在体内外炎症爪关节滑液巨噬细胞上均有表达，而在其他组织中的表达相对较低。在SPECT/Micro-CT成像中使用纳米抗体来对抗MMR，可以在体内追踪关节炎关节中的炎性细胞。
Rheumatoid arthritis (RA) is a chronic autoimmune disease occurring in approximately 1% of the worldwide population. The disease primarily affects the joints, where inflammatory cells, such as macrophages, invade the synovium and cause cartilage and bone destruction. Currently, it is difficult to efficiently diagnose and monitor early-stage RA. In this study, we investigated whether SPECT/micro-CT imaging with Tc-99m-labeled Nanobodies directed against the macrophage mannose receptor (MMR) is a useful tool for monitoring and quantifying joint inflammation in collagen-induced arthritis (CIA), a mouse model for RA. The expression of MMR was analyzed on macrophages and osteoclasts generated in vitro and in cells obtained from various organs from mice with CIA. Methods: CIA was induced in DBA/1 mice by injection of collagen type II in complete Freund adjuvant, and cell suspensions from the inflamed joints and other organs were obtained. Macrophages and osteoclasts were generated in vitro from bone marrow cells. Expression of MMR was quantified by quantitative polymerase chain reaction and flow cytometry with specific Nanobodies and conventional antibodies. SPECT/micro-CT imaging was performed with Tc-99m-labeled MMR and control Nanobodies. Results: MMR was highly expressed on macrophages and to a lesser extent on osteoclasts generated in vitro. In mice with CIA, MMR expression was detected on cells from the bone marrow, lymph nodes, and spleen. In synovial fluid of arthritic joints, MMR was expressed on CD11b(+)F4/80(+) macrophages. On in vivo SPECT/micro-CT imaging with consecutive injections of MMR and control Nanobodies, a strong MMR signal was seen in the knees, ankles, and toes of arthritic mice. Quantification of the SPECT imaging confirmed the specificity of the MMR signal in inflamed joints as compared with the control Nanobody. Dissection of the paws revealed an additional significant MMR signal in nonarthritic paws of affected mice (i.e., mice displaying symptoms of arthritis in other paws). Conclusion: Our data show that MMR is expressed on macrophages in vitro and in vivo in synovial fluid of inflamed paws, whereas expression is relatively low in other tissues. The use of Nanobodies against MMR in SPECT/micro-CT imaging generates the possibility to track inflammatory cells in vivo in arthritic joints.