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Gao S, Hu W, Zheng X, Cai S, Wu J. Functionalized aptamer with an antiparallel G-quadruplex: Structural remodeling, recognition mechanism, and diagnostic applications targeting CTGF. Biosens Bioelectron 2019; 142:111475. [PMID: 31288216 DOI: 10.1016/j.bios.2019.111475] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/01/2019] [Accepted: 06/24/2019] [Indexed: 01/01/2023]
Abstract
Connective tissue growth factor (CTGF), a widely used biomarker, is involved in many diseases, such as diabetic retinopathy, diabetic nephropathy, and rheumatoid arthritis, and it is often over-expressed in human malignant tumors. Therefore, sensitive, specific and efficient detection methods for CTGF are needed for the early diagnosis and assessment of prognosis. In this study, an aptamer, APT1, that specifically binds to CTGF was obtained by SELEX technology. Circular dichroism spectroscopy indicated that APT1 formed interconvertible parallel and antiparallel G-quadruplexes. Mutation and truncation strategies optimized APT1 and improved its functions, yielding APT1M6T, which folded into an antiparallel G-quadruplex with higher targeting affinity. A stable APT1M6T-CTGF complex model was established by molecular simulation, which helped elucidate the molecular recognition mechanism of APT1M6T and CTGF and also provided experimental guidance for rational site-directed modification of APT1M6T. A locked nucleic acid sequence was then integrated into APT1M6T to generate APT1M6TL, which had higher structural stability. A BLI-based enzyme-linked aptamer sandwich assay (BLI-ELASA) was successfully developed. The method exhibited a broad detection range from 0.05 to 50 nM with a low detection limit of 0.02 nM. The method showed high selectivity, reproducibility, and stability for analysis of CTGF in spiked serum and urine samples. This developed BLI-ELASA is promising and enables real-time, sensitive and rapid detection of the disease-specific biomarker CTGF.
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Affiliation(s)
- Shunxiang Gao
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Wei Hu
- Chengdu FenDi Technology Co., Ltd., Chengdu, China
| | - Xin Zheng
- Department of Clinical Laboratory, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Sheng Cai
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, Zhejiang University, Hangzhou, China.
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China.
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