Department of Nuclear Medicine, Klinikum rechts der Isar der TUM, Munich, Germany.
Institute for Cardiovascular Prevention, University Hospital of Ludwig-Maximilians-University, Munich, Germany.
Theranostics. 2021 Jan 1;11(4):1864-1876. doi: 10.7150/thno.50247. eCollection 2021.
The high expression of Galectin-3 (Gal3) in macrophages of atherosclerotic plaques suggests its participation in atherosclerosis pathogenesis, and raises the possibility to use it as a target to image disease severity . Here, we explored the feasibility of tracking atherosclerosis by targeting Gal3 expression in plaques of apolipoprotein E knockout (ApoE-KO) mice PET imaging. Targeting of Gal3 in M0-, M1- and M2 (M2a/M2c)-polarized macrophages was assessed using a Gal3-F(ab') mAb labeled with AlexaFluor®488 and Zr- desferrioxamine-thioureyl-phenyl-isothiocyanate (DFO). To visualize plaques , ApoE-KO mice were injected i.v. with Zr-DFO-Gal3-F(ab') mAb and imaged via PET/CT 48 h post injection. Whole length aortas harvested from euthanized mice were processed for Sudan-IV staining, autoradiography, and immunostaining for Gal3, CD68 and α-SMA expression. To confirm accumulation of the tracer in plaques, ApoE-KO mice were injected i.v. with Cy5.5-Gal3-F(ab') mAb, euthanized 48 h post injection, followed by cryosections of the body and acquisition of fluorescent images. To explore the clinical potential of this imaging modality, immunostaining for Gal3, CD68 and α-SMA expression were carried out in human plaques. Single cell RNA sequencing (scRNA-Seq) analyses were performed to measure LGALS3 (i.e. a synonym for Gal3) gene expression in each macrophage of several subtypes present in murine or human plaques. Preferential binding to M2 macrophages was observed with both AlexaFluor®488-Gal3-F(ab') and Zr-DFO-Gal3-F(ab') mAbs. Focal and specific Zr-DFO-Gal3-F(ab') mAb uptake was detected in plaques of ApoE-KO mice by PET/CT. Autoradiography and immunohistochemical analyses of aortas confirmed the expression of Gal3 within plaques mainly in macrophages. Moreover, a specific fluorescent signal was visualized within the lesions of vascular structures burdened by plaques in mice. Gal3 expression in human plaques showed similar Gal3 expression patterns when compared to their murine counterparts. Our data reveal that Zr-DFO-Gal3-F(ab') mAb PET/CT is a potentially novel tool to image atherosclerotic plaques at different stages of development, allowing knowledge-based tailored individual intervention in clinically significant disease.
Galectin-3（Gal3）在动脉粥样硬化斑块中的巨噬细胞中的高表达表明其参与了动脉粥样硬化的发病机制，并提出了将其用作成像疾病严重程度的靶标的可能性。在这里，我们通过靶向载脂蛋白 E 敲除（ApoE-KO）小鼠斑块中的 Gal3 表达来探索通过 PET 成像追踪动脉粥样硬化的可行性。使用用 AlexaFluor®488 标记的 Gal3-F(ab')mAb 评估 Gal3 在 M0-、M1-和 M2（M2a/M2c）极化巨噬细胞中的靶向性，并通过 Zr-去铁胺-硫代苯甲酰基-异硫氰酸酯（DFO）进行 PET/CT 成像。为了可视化斑块，ApoE-KO 小鼠静脉注射 Zr-DFO-Gal3-F(ab')mAb，并在注射后 48 小时通过 PET/CT 进行成像。从安乐死的小鼠中收获全长主动脉，并进行苏丹-IV 染色、放射自显影和 Gal3、CD68 和 α-SMA 表达的免疫染色。为了确认示踪剂在斑块中的积累，ApoE-KO 小鼠静脉注射 Cy5.5-Gal3-F(ab')mAb，在注射后 48 小时安乐死，然后对身体进行冷冻切片并获取荧光图像。为了探索这种成像方式的临床潜力，对人斑块中的 Gal3、CD68 和 α-SMA 表达进行了免疫染色。进行了单细胞 RNA 测序（scRNA-Seq）分析，以测量几种在鼠或人斑块中存在的巨噬细胞亚型中 LGALS3（即 Gal3 的同义词）基因的表达。用 AlexaFluor®488-Gal3-F(ab')和 Zr-DFO-Gal3-F(ab')mAb 观察到对 M2 巨噬细胞的优先结合。通过 PET/CT 在 ApoE-KO 小鼠的斑块中检测到 Zr-DFO-Gal3-F(ab')mAb 的局灶性和特异性摄取。对主动脉的放射自显影和免疫组织化学分析证实了 Gal3 在斑块中的表达主要在巨噬细胞中。此外，在斑块负担的血管结构的病变中观察到了特定的荧光信号。与它们的鼠类对应物相比，人斑块中的 Gal3 表达显示出相似的 Gal3 表达模式。我们的数据表明，Zr-DFO-Gal3-F(ab')mAb PET/CT 可能是一种新型工具，可用于成像不同阶段的动脉粥样硬化斑块，从而为临床上有意义的疾病提供基于知识的个体化干预。
