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Observations of the Effects of Angiotensin II Receptor Blocker on Angiotensin II-Induced Morphological and Mechanical Changes in Renal Tubular Epithelial Cells Using Atomic Force Microscopy. BIOMED RESEARCH INTERNATIONAL 2018; 2018:9208795. [PMID: 29888284 PMCID: PMC5985133 DOI: 10.1155/2018/9208795] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/19/2018] [Indexed: 11/17/2022]
Abstract
Objective Angiotensin II (Ang II) plays a profibrotic role in the kidneys. Although many pathways of Ang II have been discovered, the morphological and mechanical aspects have not been well investigated. We observed the changes in tubular epithelial cells (TECs) after Ang II treatment with or without Ang II receptor blockers (ARBs) using atomic force microscopy (AFM). Methods TECs were stimulated with Ang II with or without telmisartan, PD123319, and blebbistatin. AFM was performed to measure the cellular stiffness, cell volume, and cell surface roughness. Epithelial to mesenchymal transition markers were determined via immunocytochemistry. Results After Ang II stimulation, cells transformed to a flattened and elongated mesenchymal morphology. Cell surface roughness and volume significantly increased in Ang II treated TECs. Ang II also induced an increase in phospho-myosin light chain and F-actin and a decrease in E-cadherin. Ang II coincubation with either telmisartan or blebbistatin attenuated these Ang II-induced changes. Conclusion We report, for the first time, the use of AFM in directly observing the changes in TECs after Ang II treatment with or without ARBs. Simultaneously, we successfully measured the selective effect of PD123319 or blebbistatin. AFM could be a noninvasive evaluating strategy for cellular processes in TECs.
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Li W, Xu J, Kou X, Zhao R, Zhou W, Fang X. Single-molecule force spectroscopy study of interactions between angiotensin II type 1 receptor and different biased ligands in living cells. Anal Bioanal Chem 2018; 410:3275-3284. [PMID: 29492619 DOI: 10.1007/s00216-018-0956-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/12/2018] [Accepted: 02/09/2018] [Indexed: 01/14/2023]
Abstract
Angiotensin II type 1 receptor (AT1R), a typical G protein-coupled receptor, plays a key role in regulating many cardiovascular functions. Different ligands can bind with AT1R to selectively activate either G protein (Gq) or β-arrestin (β-arr) pathway, or both pathways, but the molecular mechanism is not clear yet. In this work, we used, for the first time, atomic force microscopy-based single molecule force spectroscopy (SMFS) to study the interactions of AT1R with three types of ligands, balanced ligand, Gq-biased ligand, and β-arr-biased ligand, in living cells. The results revealed their difference in binding force and binding stability. The complex of the Gq-biased ligand-AT1R overcame two energy barriers with an intermediate state during dissociation, whereas that of β-arr-biased ligand-AT1R complex overcame one energy barrier. This indicated that AT1R had different ligand-binding conformational substates and underwent different structural changes to activate downstream signaling pathways with variable agonist efficacies. Quantitative analysis of AT1R-ligand binding in living cells at the single-molecule level offers a new tool to study the molecular mechanism of AT1R biased activation. Graphical Abstract Single-molecule force measurement on the living cell expressing AT1R-eGFP with a ligand modified AFM tip (left), the dynamic force spectra of β-arrestin biased ligands-AT1R (middle), and Gq-biased ligands-AT1R (right). The complexes of β-arr-biased ligand-AT1R overcame one energy barrier, with one linear region in the spectra, whereas the Gq-biased ligand-AT1R complexes overcame two energy barriers with two linear regions.
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Affiliation(s)
- Wenhui Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, 2 North First Street, Zhongguancun, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiachao Xu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, 2 North First Street, Zhongguancun, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaolong Kou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, 2 North First Street, Zhongguancun, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Rong Zhao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, 2 North First Street, Zhongguancun, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Zhou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, 2 North First Street, Zhongguancun, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaohong Fang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, 2 North First Street, Zhongguancun, Beijing, 100190, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
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Lamprecht C, Hinterdorfer P, Ebner A. Applications of biosensing atomic force microscopy in monitoring drug and nanoparticle delivery. Expert Opin Drug Deliv 2014; 11:1237-53. [PMID: 24809228 DOI: 10.1517/17425247.2014.917078] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The therapeutic effects of medicinal drugs not only depend on their properties, but also on effective transport to the target receptor. Here we highlight recent developments in this discipline and show applications of atomic force microscopy (AFM) that enable us to track the effects of drugs and the effectiveness of nanoparticle delivery at the single molecule level. AREAS COVERED Physiological AFM imaging enables visualization of topographical changes to cells as a result of drug exposure and allows observation of cellular responses that yield morphological changes. When we upgrade the regular measuring tip to a molecular biosensor, it enables investigation of functional changes at the molecular level via single molecule force spectroscopy. EXPERT OPINION Biosensing AFM techniques have generated powerful tools to monitor drug delivery in (living) cells. While technical developments in actual AFM methods have simplified measurements at relevant physiological conditions, understanding both the biological and technical background is still a crucial factor. However, due to its potential impact, we expect the number of application-based biosensing AFM techniques to further increase in the near future.
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Affiliation(s)
- Constanze Lamprecht
- University of Kiel, Institute of Materials Science Biocompatible Nanomaterials , Kaiserstr.2, 24143 Kiel , Germany
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Jeong KH, Lee SH. A new technical approach to monitor the cellular physiology by atomic force microscopy. Electrolyte Blood Press 2013; 10:7-11. [PMID: 23508877 PMCID: PMC3597918 DOI: 10.5049/ebp.2012.10.1.7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 12/12/2012] [Indexed: 11/05/2022] Open
Abstract
Atomic force microscopy (AFM) has become an important medical and biological tool for non-invasive imaging and measuring the mechanical changes of cells since its invention by Binnig et al. AFM can be used to investigate the mechanical properties of cellular events in individual living cells on a nanoscale level. In addition, the dynamic cellular movements induced by biochemical activation of specific materials can be detected in real time with three dimensional resolution. Force measurement with the use of AFM has become the tool of choice to monitor the mechanical changes of variable cellular events. In addition, the AFM approach can be applied to measure cellular adhesion properties. Moreover, the information gathered from AFM is important to understanding the mechanisms related to cellular movement and mechanical regulation. This review will discuss recent contributions of AFM to cellular physiology with a focus on monitoring the effects of antihypertensive agents in kidney cells.
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Affiliation(s)
- Kyung Hwan Jeong
- Department of Internal Medicine, College of Medicine, Kyung Hee University, Seoul, Korea
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