Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province 519000, China.
Department of Ultrasound Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province 519000, China.
Mol Pharm. 2022 Nov 7;19(11):4264-4274. doi: 10.1021/acs.molpharmaceut.2c00584. Epub 2022 Sep 6.
Tracking the pathogen of coronavirus disease 2019 (COVID-19) in live subjects may help estimate the spatiotemporal distribution of SARS-CoV-2 infection . This study developed a positron emission tomography (PET) tracer of the S2 subunit of spike (S) protein for imaging SARS-CoV-2. A pan-coronavirus inhibitor, EK1 peptide, was synthesized and radiolabeled with copper-64 after being conjugated with 1,4,7-triazacyclononane-1,4,7-triyl-triacetic acid (NOTA). The stability tests indicated that [Cu]Cu-NOTA-EK1 was stable up to 24 h both in saline and in human serum. The binding assay showed that [Cu]Cu-NOTA-EK1 has a nanomolar affinity ( = 3.94 ± 0.51 nM) with the S-protein of SARS-CoV-2. The cell uptake evaluation used HEK293T/S and HEK293T/S cell lines that showed that the tracer has a high affinity with the S-protein on the cellular level. For the study, we tested [Cu]Cu-NOTA-EK1 in HEK293T/S cell xenograft-bearing mice ( = 3) and pseudovirus of SARS-CoV-2-infected HEK293T/ACE2 cell bearing mice ( = 3). The best radioactive xenograft-to-muscle ratio (/ 8.04 ± 0.99, / 6.47 ± 0.71) was most evident 4 h postinjection. Finally, PET imaging in the surrogate mouse model of beta-coronavirus, mouse hepatic virus-A59 infection in C57BL/6 J mice showed significantly enhanced accumulation in the liver than in the uninfected mice (1.626 ± 0.136 vs 0.871 ± 0.086 %ID/g, = 3, < 0.05) at 4 h postinjection. In conclusion, our experimental results demonstrate that [Cu]Cu-NOTA-EK1 is a potential molecular imaging probe for tracking SARS-CoV-2 in extrapulmonary infections in living subjects.
在活体受试者中追踪 2019 年冠状病毒病（COVID-19）的病原体可能有助于估计 SARS-CoV-2 感染的时空分布。本研究开发了一种用于 SARS-CoV-2 成像的刺突（S）蛋白 S2 亚单位的正电子发射断层扫描（PET）示踪剂。一种泛冠状病毒抑制剂 EK1 肽在与 1,4,7-三氮杂环壬烷-1,4,7-三基三乙酸（NOTA）缀合后被合成并放射性标记铜-64。稳定性测试表明，[Cu]Cu-NOTA-EK1 在生理盐水和人血清中均稳定长达 24 小时。结合实验表明，[Cu]Cu-NOTA-EK1 与 SARS-CoV-2 的 S 蛋白具有纳摩尔亲和力（=3.94±0.51 nM）。细胞摄取评估使用表达 SARS-CoV-2 刺突蛋白的 HEK293T/S 和 HEK293T/S 细胞系进行，表明示踪剂在细胞水平上与 S 蛋白具有高亲和力。为此研究，我们在 HEK293T/S 细胞异种移植瘤荷瘤小鼠（n=3）和 SARS-CoV-2 感染的 HEK293T/ACE2 细胞假病毒荷瘤小鼠（n=3）中测试了 [Cu]Cu-NOTA-EK1。注射后 4 小时，最佳放射性异种瘤与肌肉比值（/8.04±0.99，/6.47±0.71）最为明显。最后，在 C57BL/6 J 小鼠乙型冠状病毒替代小鼠模型中进行 PET 成像，显示在感染小鼠肝脏中的摄取明显高于未感染小鼠（1.626±0.136 比 0.871±0.086 %ID/g，n=3，<0.05）。总之，我们的实验结果表明，[Cu]Cu-NOTA-EK1 是一种潜在的分子成像探针，可用于追踪活体受试者中肺外感染的 SARS-CoV-2。
