南京大学叶德举团队开发了一种可激活的近红外荧光探针，用于靶向磷脂酰丝氨酸和半胱氨酸蛋白酶-3的急性肾损伤活体成像。相关研究成果于2021年10月21日发表在国际顶尖学术期刊《美国化学会杂志》。

肾脏可清除和靶向响应近红外（NIR）荧光成像探针在急性肾损伤（AKI）的活体诊断中具有广阔的应用前景。然而，设计一种肾脏可清除且同时对多个分子靶点有反应的成像探针以促进AKI的早期检测并提高灵敏度和特异性是一项挑战。

该文中，研究人员通过利用受体介导的结合和保留效应以及酶触发的荧光激活，使用“一锅顺序点击反应”方法设计和合成了可激活的小分子NIR荧光探针（1-DPA2）。1-DPA2可靶向外化磷脂酰丝氨酸（PS）和活性半胱天冬酶-3（Casp-3）(两种凋亡的重要生物标记物)，产生增强的808nm近红外荧光和高信号背景比（SBR），可在顺铂治疗后24小时检测小鼠顺铂诱导的AKI的发生。研究人员不仅可以监测AKI进展时小鼠肾脏中Casp-3的逐渐激活，还可以通过1-DPA2实时荧光成像报告N-乙酰-l-半胱氨酸（NAC）治疗后AKI小鼠肾功能的逐渐恢复。

该研究证明了1-DPA2通过同时靶向PS外化和Casp-3激活来纵向监测肾细胞凋亡的能力，对于AKI的早期诊断是有效的，并且有助于预测潜在的药物肾毒性以及体内筛选抗AKI药物的疗效。

附：英文原文

Title: An Activatable Near-Infrared Fluorescence Probe for in Vivo Imaging of Acute Kidney Injury by Targeting Phosphatidylserine and Caspase-3

Author: Jianhui Weng, Yuqi Wang, Yan Zhang, Deju Ye

Issue&Volume: October 21, 2021

Abstract: Renal-clearable and target-responsive near-infrared (NIR) fluorescent imaging probes have been promising for in vivo diagnosis of acute kidney injury (AKI). However, designing an imaging probe that is renal-clearable and concurrently responsive toward multiple molecular targets to facilitate early detection of AKI with improved sensitivity and specificity is challenging. Herein, by leveraging the receptor-mediated binding and retention effect along with enzyme-triggered fluorescence activation, we design and synthesize an activatable small-molecule NIR fluorescent probe (1-DPA2) using a “one-pot sequential click reaction” approach. 1-DPA2 can target both the externalized phosphatidylserine (PS) and active caspase-3 (Casp-3), two essential biomarkers of apoptosis, producing enhanced 808 nm NIR fluorescence and a high signal-to-background ratio (SBR) amenable to detecting the onset of cisplatin-induced AKI in mice as early as 24 h post-treatment with cisplatin. We not only monitor the gradual activation of Casp-3 in the kidney of mice upon AKI progression but also can report on the progressive recovery of kidney functions in AKI mice following N-acetyl-l-cysteine (NAC) therapy via real-time fluorescence imaging by 1-DPA2. This study demonstrates the ability of 1-DPA2 for longitudinal monitoring of renal cell apoptosis by concurrently targeting PS externalization and Casp-3 activation, which is efficient for early diagnosis of AKI and useful for prediction of potential drug nephrotoxicity as well as in vivo screening of anti-AKI drugs’ efficacy.

DOI: 10.1021/jacs.1c08898

Source: https://pubs.acs.org/doi/10.1021/jacs.1c08898