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Foo YY, Motakis E, Tiang Z, Shen S, Lai JKH, Chan WX, Wiputra H, Chen N, Chen CK, Winkler C, Foo RSY, Yap CH. Effects of extended pharmacological disruption of zebrafish embryonic heart biomechanical environment on cardiac function, morphology, and gene expression. Dev Dyn 2021; 250:1759-1777. [PMID: 34056790 DOI: 10.1002/dvdy.378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/24/2021] [Accepted: 05/13/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Biomechanical stimuli are known to be important to cardiac development, but the mechanisms are not fully understood. Here, we pharmacologically disrupted the biomechanical environment of wild-type zebrafish embryonic hearts for an extended duration and investigated the consequent effects on cardiac function, morphological development, and gene expression. RESULTS Myocardial contractility was significantly diminished or abolished in zebrafish embryonic hearts treated for 72 hours from 2 dpf with 2,3-butanedione monoxime (BDM). Image-based flow simulations showed that flow wall shear stresses were abolished or significantly reduced with high oscillatory shear indices. At 5 dpf, after removal of BDM, treated embryonic hearts were maldeveloped, having disrupted cardiac looping, smaller ventricles, and poor cardiac function (lower ejected flow, bulboventricular regurgitation, lower contractility, and slower heart rate). RNA sequencing of cardiomyocytes of treated hearts revealed 922 significantly up-regulated genes and 1,698 significantly down-regulated genes. RNA analysis and subsequent qPCR and histology validation suggested that biomechanical disruption led to an up-regulation of inflammatory and apoptotic genes and down-regulation of ECM remodeling and ECM-receptor interaction genes. Biomechanics disruption also prevented the formation of ventricular trabeculation along with notch1 and erbb4a down-regulation. CONCLUSIONS Extended disruption of biomechanical stimuli caused maldevelopment, and potential genes responsible for this are identified.
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Affiliation(s)
- Yoke Yin Foo
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Efthymios Motakis
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Zenia Tiang
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Shuhao Shen
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Jason Kuan Han Lai
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Wei Xuan Chan
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Hadi Wiputra
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Nanguang Chen
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Ching Kit Chen
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Division of Cardiology, Department of Paediatrics, Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore, Singapore
| | - Christoph Winkler
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Roger Sik Yin Foo
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Choon Hwai Yap
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.,Department of Bioengineering, Imperial College London, London, UK
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Du E, Shen S, Chong SP, Chen N. Multifunctional laser speckle imaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:2007-2016. [PMID: 32341863 PMCID: PMC7173886 DOI: 10.1364/boe.388856] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/07/2020] [Accepted: 03/07/2020] [Indexed: 05/02/2023]
Abstract
We have developed a multi-functional laser speckle imaging system, which can be operated in both the surface illumination laser speckle contrast imaging (SI-LSCI) mode and the line scan laser speckle contrast imaging (LS-LSCI) mode. The system has been applied to imaging the chicken embryos to visualize both the blood flow and morphological details of the vasculature. The experimental results demonstrated that LS-LSCI is capable of detecting and quantifying blood flow in blood vessels smaller and deeper than those detectable by conventional SI-LSCI. Furthermore, the line scan mode is also capable of producing depth-resolved absorption-based morphological images of tissue, augmenting flow-based functional images.
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Advanced blood flow assessment in Zebrafish via experimental digital particle image velocimetry and computational fluid dynamics modeling. Micron 2020; 130:102801. [DOI: 10.1016/j.micron.2019.102801] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/18/2019] [Accepted: 12/13/2019] [Indexed: 01/23/2023]
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Shen S, Wu J, Chen N. Quadrature demodulation in line-scan focal modulation microscopy for imaging three-dimensional zebrafish neural structure. JOURNAL OF BIOPHOTONICS 2020; 13:e201900170. [PMID: 31343833 DOI: 10.1002/jbio.201900170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/23/2019] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Visualizing biological processes in neuroscience requires in vivo functional imaging at single-neuron resolution, high image acquisition speed and strong optical sectioning ability. However, due to light scattering of in tissue, very often conventional wide-field fluorescence microscopes are unable to resolve cells in the presence of a strong out-of-focus background. Line-scan focal modulation microscopy enables high temporal resolution and good optical sectioning ability at the same time. Here we demonstrate a quadrature demodulation method to extract the focal information with an extended frequency bandwidth and therefore higher spatial resolution. The performance of the demodulation scheme in line-scan focal modulation microscope has been evaluated by performing imaging experiments with fluorescence beads and zebrafish neural structure. Reduced background, reduced artifacts and more detailed morphological information are evident in the obtained images.
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Affiliation(s)
- Shuhao Shen
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Jian Wu
- Institute of Biomedical Engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Nanguang Chen
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
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Tang J, Han KY. Low-photobleaching line-scanning confocal microscopy using dual inclined beams. JOURNAL OF BIOPHOTONICS 2019; 12:e201900075. [PMID: 31111688 DOI: 10.1002/jbio.201900075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/22/2019] [Accepted: 05/17/2019] [Indexed: 06/09/2023]
Abstract
Confocal microscopy is an indispensable tool for biological imaging due to its high resolution and optical sectioning capability. However, its slow imaging speed and severe photobleaching have largely prevented further applications. Here, we present dual inclined beam line-scanning (LS) confocal microscopy. The reduced excitation intensity of our imaging method enabled a 2-fold longer observation time of fluorescence compared to traditional LS microscopy while maintaining a good sectioning capability and single-molecule sensitivity. We characterized the performance of our method and applied it to subcellular imaging and three-dimensional single-molecule RNA imaging in mammalian cells.
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Affiliation(s)
- Jialei Tang
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida
| | - Kyu Young Han
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida
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Foo YY, Pant S, Tay HS, Imangali N, Chen N, Winkler C, Yap CH. 4D modelling of fluid mechanics in the zebrafish embryonic heart. Biomech Model Mechanobiol 2019; 19:221-232. [PMID: 31446522 DOI: 10.1007/s10237-019-01205-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 07/20/2019] [Indexed: 11/30/2022]
Abstract
Abnormal blood flow mechanics can result in pathological heart malformation, underlining the importance of understanding embryonic cardiac fluid mechanics. In the current study, we performed image-based computational fluid dynamics simulation of the zebrafish embryonic heart ventricles and characterized flow mechanics, organ dynamics, and energy dynamics in detail. 4D scans of 5 days post-fertilization embryonic hearts with GFP-labelled myocardium were acquired using line-scan focal modulation microscopy. This revealed that the zebrafish hearts exhibited a wave-like contractile/relaxation motion from the inlet to the outlet during both systole and diastole, which we showed to be an energy efficient configuration. No impedance pumping effects of pressure and velocity waves were observed. Due to its tube-like configuration, inflow velocities were higher near the inlet and smaller at the outlet and vice versa for outflow velocities. This resulted in an interesting spatial wall shear stress (WSS) pattern where WSS waveforms near the inlet and those near the outlet were out of phase. There was large spatial variability in WSS magnitudes. Peak WSS was in the range of 47.5-130 dyne/cm2 at the inflow and outflow tracts, but were much smaller, in the range of 4-11 dyne/cm2, in the mid-ventricular segment. Due to very low Reynolds number and the highly viscous environment, intraventricular pressure gradients were high, suggesting substantial energy losses of flow through the heart.
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Affiliation(s)
- Yoke Yin Foo
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Shilpa Pant
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Huiping Shermaine Tay
- Department of Biological Science, National University of Singapore, Singapore, Singapore
| | - Nurgul Imangali
- Department of Biological Science, National University of Singapore, Singapore, Singapore
| | - Nanguang Chen
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Christoph Winkler
- Department of Biological Science, National University of Singapore, Singapore, Singapore
| | - Choon Hwai Yap
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.
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Wang M, Chen N. Three-dimensional cellular imaging in thick biological tissue with confocal detection of one-photon fluorescence in the near-infrared II window. JOURNAL OF BIOPHOTONICS 2019; 12:e201800459. [PMID: 30663282 DOI: 10.1002/jbio.201800459] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/15/2019] [Accepted: 01/17/2019] [Indexed: 06/09/2023]
Abstract
Fluorescence imaging in the second near-infrared optical window (NIR-II, 900-1700 nm) has become a technique of choice for noninvasive in vivo imaging in recent years. Greater penetration depths with high spatial resolution and low background can be achieved with this NIR-II window, owing to low autofluorescence within this optical range and reduced scattering of long wavelength photons. Here, we present a novel design of confocal laser scanning microscope tailored for imaging in the NIR-II window. We showcase the outstanding penetration depth of our confocal setup with a series of imaging experiments. HeLa cells labeled with PbS quantum dots with a peak emission wavelength of 1276 nm can be visualized through a 3.5-mm-thick layer of scattering medium, which is a 0.8% Lipofundin solution. A commercially available organic dye IR-1061 (emission peak at 1132 nm), in its native form, is used for the first time, as a NIR-II fluorescence label in cellular imaging. Our confocal setup is capable of capturing optically sectioned images of IR-1061 labeled chondrocytes in fixed animal cartilage at a depth up to 800 μm, with a superb spatial resolution of around 2 μm.
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Affiliation(s)
- Menghan Wang
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Nanguang Chen
- Department of Biomedical Engineering, National University of Singapore, Singapore
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Chen R, Shen S, Chen N. Numerical modeling of two-photon focal modulation microscopy with a sinusoidal phase filter. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-8. [PMID: 29740994 DOI: 10.1117/1.jbo.23.5.055002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/19/2018] [Indexed: 06/08/2023]
Abstract
A spatiotemporal phase modulator (STPM) is theoretically investigated using the vectorial diffraction theory. The STPM is equivalent to a time-dependent phase-only pupil filter that alternates between a homogeneous filter and a stripe-shaped filter with a sinusoidal phase distribution. It is found that two-photon focal modulation microscopy (TPFMM) using this STPM can significantly suppress the background contribution from out-of-focus ballistic excitation and achieve almost the same resolution as two-photon microscopy. The modulation depth is also evaluated and a compromise exists between the signal-to-background ratio and signal-to-noise ratio. The theoretical investigations provide important insights into future implementations of TPFMM and its potential to further extend the penetration depth of nonlinear microscopy in imaging multiple-scattering biological tissues.
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Affiliation(s)
- Rui Chen
- National Univ. of Singapore, Singapore
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Shen S, Pant S, Chen R, Chen N. Effects of pupil filter patterns in line-scan focal modulation microscopy. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-6. [PMID: 29549668 DOI: 10.1117/1.jbo.23.3.036008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 02/27/2018] [Indexed: 06/08/2023]
Abstract
Line-scan focal modulation microscopy (LSFMM) is an emerging imaging technique that affords high imaging speed and good optical sectioning at the same time. We present a systematic investigation into optimal design of the pupil filter for LSFMM in an attempt to achieve the best performance in terms of spatial resolutions, optical sectioning, and modulation depth. Scalar diffraction theory was used to compute light propagation and distribution in the system and theoretical predictions on system performance, which were then compared with experimental results.
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Affiliation(s)
- Shuhao Shen
- National University of Singapore, Optical Bioimaging Laboratory, Department of Biomedical Engineerin, Singapore
| | - Shilpa Pant
- Nanyang Technological University, School of Electrical and Electronics Engineering, Centre for Optic, Singapore
| | - Rui Chen
- National University of Singapore, Optical Bioimaging Laboratory, Department of Biomedical Engineerin, Singapore
| | - Nanguang Chen
- National University of Singapore, Optical Bioimaging Laboratory, Department of Biomedical Engineerin, Singapore
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