Name: light-sheet fluorescence microscopy to capture 4-dimensional images of the effects of modulating shear stress on the developing zebrafish heart
Uploaded: 2018-08-10T14:30:00
Description: Watch this Scientific Journal Video about Light-sheet Fluorescence Microscopy to Capture 4-Dimensional Images of the Effects of Modulating Shear Stress on the Developing Zebrafish Heart at JoVE.com

The authors would like to express gratitude to William Talbot from Stanford University for providing the Human&#160;Nrg1&#160;cDNA and to Deborah Yelon from UCSD for providing the&#160;wea&#160;mutants. The authors would also like to thank Cynthia Chen for helping with image acquisition. This study was supported by grants NIH HL118650 (to T.K. Hsiai), HL083015 (to T.K. Hsiai), HD069305 (to N.C. Chi and T.K. Hsiai.), HL111437 (to T.K. Hsiai and N.C. Chi), HL129727 (to T.K. Hsiai), T32HL007895 (to R.R. Sevag Packard), HL 134613 (to V. Messerschmidt) and University of Texas System STARS funding (to J. Lee).

The following methods were performed in compliance with UTA and UCLA IACUC protocols. These experimental groups were used with transgenic Tg(cmlc2:gfp), the wea (weak atrium) or clo (cloche) mutants: (a) wild-type (WT) control, (b) gata1a MO, and (c) tnnt2a MO injections (Table 1).
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			<td>Model</td>
			<td>Name</td>
	...

<ol>
	<li>Lee, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moving+domain+computational+fluid+dynamics+to+interface+with+an+embryonic+model+of+cardiac+morphogenesis.">Moving domain computational fluid dynamics to interface with an embryonic model of cardiac morphogenesis.</a> PLoS One. 8 (8), e72924 (2013).</li><li>Peshkovsky, C., Totong, R., Yelon, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dependence+of+cardiac+trabeculation+on+neuregulin+signaling+and+blood+flow+in+zebrafish.">Dependence of cardiac trabeculation on neuregulin signaling and blood flow in zebrafish.</a> Dev Dyn. 240 (2), 446-456 (2011).</li><li>High, F. A., Epstein, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+multifaceted+role+of+Notch+in+cardiac+development+and+disease.">The multifaceted role of Notch in cardiac development and disease.</a> Nat Rev Genet. 9 (1), 49-61 (2008).</li><li>Galloway, J. L., Wingert, R. A., Thisse, C., Thisse, B., Zon, L. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+Gata1+but+Not+Gata2+Converts+Erythropoiesis+to+Myelopoiesis+in+Zebrafish+Embryos.">Loss of Gata1 but Not Gata2 Converts Erythropoiesis to Myelopoiesis in Zebrafish Embryos.</a> Developmental Cell. 8 (1), 109-116 (2005).</li><li>Chi, N. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+conduction+is+required+to+preserve+cardiac+chamber+morphology.">Cardiac conduction is required to preserve cardiac chamber morphology.</a> Proceedings of the National Academy of Sciences. 107 (33), 14662 (2010).</li><li>Paffett-Lugassy, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+conservation+of+erythropoietin+signaling+in+zebrafish.">Functional conservation of erythropoietin signaling in zebrafish.</a> Blood. 110 (7), 2718 (2007).</li><li>De Luca, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ZebraBeat:+a+flexible+platform+for+the+analysis+of+the+cardiac+rate+in+zebrafish+embryos.">ZebraBeat: a flexible platform for the analysis of the cardiac rate in zebrafish embryos.</a> Scientific Reports. 4, 4898 (2014).</li><li>Liu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+dual+role+for+ErbB2+signaling+in+cardiac+trabeculation.">A dual role for ErbB2 signaling in cardiac trabeculation.</a> Development. 137 (22), 3867-3875 (2010).</li><li>Samsa, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+contraction+activates+endocardial+Notch+signaling+to+modulate+chamber+maturation+in+zebrafish.">Cardiac contraction activates endocardial Notch signaling to modulate chamber maturation in zebrafish.</a> Development. 142 (23), 4080-4091 (2015).</li><li>Li, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+genetic+analysis+in+mice+unveils+central+role+for+cilia+in+congenital+heart+disease.">Global genetic analysis in mice unveils central role for cilia in congenital heart disease.</a> Nature. 521, 520 (2015).</li><li>Sifrim, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+genetic+architectures+for+syndromic+and+nonsyndromic+congenital+heart+defects+identified+by+exome+sequencing.">Distinct genetic architectures for syndromic and nonsyndromic congenital heart defects identified by exome sequencing.</a> Nature Genetics. 48, 1060 (2016).</li><li>Hu, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+genome-wide+association+study+identifies+two+risk+loci+for+congenital+heart+malformations+in+Han+Chinese+populations.">A genome-wide association study identifies two risk loci for congenital heart malformations in Han Chinese populations.</a> Nature Genetics. 45, 818 (2013).</li><li>Huisken, J., Stainier, D. Y. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+plane+illumination+microscopy+techniques+in+developmental+biology.">Selective plane illumination microscopy techniques in developmental biology.</a> Development (Cambridge, England). 136 (12), 1963-1975 (2009).</li><li>Panier, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+functional+imaging+of+multiple+brain+regions+in+intact+zebrafish+larvae+using+Selective+Plane+Illumination+Microscopy.">Fast functional imaging of multiple brain regions in intact zebrafish larvae using Selective Plane Illumination Microscopy.</a> Frontiers in Neural Circuits. 7, 65 (2013).</li><li>Lee, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ACT-PRESTO:+Rapid+and+consistent+tissue+clearing+and+labeling+method+for+3-dimensional+(3D)+imaging.">ACT-PRESTO: Rapid and consistent tissue clearing and labeling method for 3-dimensional (3D) imaging.</a> Scientific Reports. 6, 18631 (2016).</li><li>Kelley, L. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live-cell+confocal+microscopy+and+quantitative+4D+image+analysis+of+anchor-cell+invasion+through+the+basement+membrane+in+Caenorhabditis+elegans.">Live-cell confocal microscopy and quantitative 4D image analysis of anchor-cell invasion through the basement membrane in Caenorhabditis elegans.</a> Nature Protocols. 12, 2081 (2016).</li><li>Lee, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=4-Dimensional+light-sheet+microscopy+to+elucidate+shear+stress+modulation+of+cardiac+trabeculation.">4-Dimensional light-sheet microscopy to elucidate shear stress modulation of cardiac trabeculation.</a> The Journal of Clinical Investigation. 126 (5), 1679-1690 (2016).</li><li>Lavagnino, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=4D+(x-y-z-t)+imaging+of+thick+biological+samples+by+means+of+Two-Photon+inverted+Selective+Plane+Illumination+Microscopy+(2PE-iSPIM).">4D (x-y-z-t) imaging of thick biological samples by means of Two-Photon inverted Selective Plane Illumination Microscopy (2PE-iSPIM).</a> Scientific Reports. 6, 23923 (2016).</li><li>Huisken, J., Swoger, J., Del Bene, F., Wittbrodt, J., Stelzer, E. H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+Sectioning+Deep+Inside+Live+Embryos+by+Selective+Plane+Illumination+Microscopy.">Optical Sectioning Deep Inside Live Embryos by Selective Plane Illumination Microscopy.</a> Science. 305 (5686), 1007 (2004).</li><li>Hove, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracardiac+fluid+forces+are+an+essential+epigenetic+factor+for+embryonic+cardiogenesis.">Intracardiac fluid forces are an essential epigenetic factor for embryonic cardiogenesis.</a> Nature. 421 (6919), 172-177 (2003).</li><li>Bakkers, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+as+a+model+to+study+cardiac+development+and+human+cardiac+disease.">Zebrafish as a model to study cardiac development and human cardiac disease.</a> Cardiovascular Research. 91 (2), 279-288 (2011).</li><li>BioRad. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> General Protocol for Western Blotting. 6376, (2018).</li><li>GeneTools. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Gene Tools Oligo Design Website. , (2018).</li><li>Mullins, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Zebrafish Course. , (2013).</li><li>Grenander, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Probability and Statistics: The Harald Cram&#233;r Volume. , (1959).</li><li>Fei, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+Light-Sheet+Fluorescent+Microscopy+for+Multi-Scale+and+Rapid+Imaging+of+Architecture+and+Function.">Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function.</a> Scientific Reports. 6, 22489 (2016).</li><li>Liebling, M., Forouhar , A. S., Gharib, M., Fraser, S. E., Dickinson, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Four-dimensional+cardiac+imaging+in+living+embryos+via+postacquisition+synchronization+of+nongated+slice+sequences.">Four-dimensional cardiac imaging in living embryos via postacquisition synchronization of nongated slice sequences.</a> Journal of Biomedical Optics. 10 (5), (2005).</li><li>Adeoye, A. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+effects+of+exogenous+enzymes+and+probiotic+on+Nile+tilapia+(Oreochromis+niloticus)+growth,+intestinal+morphology+and+microbiome.">Combined effects of exogenous enzymes and probiotic on Nile tilapia (Oreochromis niloticus) growth, intestinal morphology and microbiome.</a> Aquaculture. 463, 61-70 (2016).</li><li>Matthews, M., Varga, Z. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anesthesia+and+Euthanasia+in+Zebrafish.">Anesthesia and Euthanasia in Zebrafish.</a> ILAR Journal. 53 (2), 192-204 (2012).</li><li>Singleman, C., Holtzman, N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+Dissection+in+Larval,+Juvenile+and+Adult+Zebrafish,+Danio+rerio.">Heart Dissection in Larval, Juvenile and Adult Zebrafish, Danio rerio.</a> Journal of Visualized Experiments : JoVE. (55), e3165 (2011).</li><li>Li, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disturbed+Flow+Induces+Autophagy,+but+Impairs+Autophagic+Flux+to+Perturb+Mitochondrial+Homeostasis.">Disturbed Flow Induces Autophagy, but Impairs Autophagic Flux to Perturb Mitochondrial Homeostasis.</a> Antioxidants &amp; Redox Signaling. 23 (15), 1207-1219 (2015).</li><li>Li, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shear+Stress-Activated+Wnt-Angiopoietin-2+Signaling+Recapitulated+Vascular+Repair+in+Zebrafish+Embryos.">Shear Stress-Activated Wnt-Angiopoietin-2 Signaling Recapitulated Vascular Repair in Zebrafish Embryos.</a> Arteriosclerosis, thrombosis, and vascular biology. 34 (10), 2268-2275 (2014).</li><li>Baek, K. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow-Responsive+Vascular+Endothelial+Growth+Factor+Receptor-Protein+Kinase+C+Isoform+Epsilon+Signaling+Mediates+Glycolytic+Metabolites+for+Vascular+Repair.">Flow-Responsive Vascular Endothelial Growth Factor Receptor-Protein Kinase C Isoform Epsilon Signaling Mediates Glycolytic Metabolites for Vascular Repair.</a> Antioxidants &amp; Redox Signaling. 28 (1), 31-43 (2018).</li><li>Huang, C. J., Tu, C. T., Hsiao, C. D., Hsieh, F. J., Tsai, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Germ-line+transmission+of+a+myocardium-specific+GFP+transgene+reveals+critical+regulatory+elements+in+the+cardiac+myosin+light+chain+2+promoter+of+zebrafish.">Germ-line transmission of a myocardium-specific GFP transgene reveals critical regulatory elements in the cardiac myosin light chain 2 promoter of zebrafish.</a> Developmental Dynamics. 228 (1), 30-40 (2003).</li><li>Vermot, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversing+blood+flows+act+through+klf2a+to+ensure+normal+valvulogenesis+in+the+developing+heart.">Reversing blood flows act through klf2a to ensure normal valvulogenesis in the developing heart.</a> PLoS Biol. 7 (11), (2009).</li><li>Grego-Bessa, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Notch+signaling+is+essential+for+ventricular+chamber+development.">Notch signaling is essential for ventricular chamber development.</a> Dev Cell. 12 (3), 415-429 (2007).</li><li>Berdougo, E., Coleman, H., Lee, D. H., Stainier, D. Y. R., Yelon, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutation+of+weak+atrium/atrial+myosin+heavy+chain+disrupts+atrial+function+and+influences+ventricular+morphogenesis+in+zebrafish.">Mutation of weak atrium/atrial myosin heavy chain disrupts atrial function and influences ventricular morphogenesis in zebrafish.</a> Development. 130 (24), 6121 (2003).</li><li>Arnaout, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+model+for+human+long+QT+syndrome.">Zebrafish model for human long QT syndrome.</a> Proc Natl Acad Sci U S A. 104 (27), 11316-11321 (2007).</li><li>Chi, N. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+and+physiologic+dissection+of+the+vertebrate+cardiac+conduction+system.">Genetic and physiologic dissection of the vertebrate cardiac conduction system.</a> PLoS Biol. 6 (5), e109 (2008).</li><li>Liao, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+zebrafish+gene+cloche+acts+upstream+of+a+flk-1+homologue+to+regulate+endothelial+cell+differentiation.">The zebrafish gene cloche acts upstream of a flk-1 homologue to regulate endothelial cell differentiation.</a> Development. 124 (2), 381-389 (1997).</li><li>Stainier, D. Y., Weinstein, B. M., Detrich, H. W., Zon, L. I., Fishman, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cloche,+an+early+acting+zebrafish+gene,+is+required+by+both+the+endothelial+and+hematopoietic+lineages.">Cloche, an early acting zebrafish gene, is required by both the endothelial and hematopoietic lineages.</a> Development. 121 (10), 3141-3150 (1995).</li><li>Santi, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light+Sheet+Fluorescence+Microscopy:+A+Review.">Light Sheet Fluorescence Microscopy: A Review.</a> Journal of Histochemistry and Cytochemistry. 59 (2), 129-138 (2011).</li><li>Engelbrecht, C. J., Stelzer, E. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolution+enhancement+in+a+light-sheet-based+microscope+(SPIM).">Resolution enhancement in a light-sheet-based microscope (SPIM).</a> Optics Letters. 31 (10), 1477-1479 (2006).</li></ol>

In this protocol, we have shown that 4-D imaging can be used to track the development of a trabecular network in response to changes in biomechanical forces. In particular, the shear stress experienced by endothelial cells initiates the Notch signaling cascade, which in turn promotes trabeculation. In this manuscript, we have shown that (1) gata1a MO injection decreased hematopoiesis and therefore it reduced wall shear stress, (2) tnnt2a MO injection inhibited ventricular contractile function to reduce ...

Biomechanical forces, such as hemodynamic shear stress, are intimately involved in cardiac morphogenesis. In response to hemodynamic shear forces, myocardial ridges and grooves develop in a wave-like trabecular network in alignment with the direction of the shear stress across the atrioventricular (AV) valve1. Cardiac trabeculation is necessary to increase contractile function and myocardial mass2. Mutations in Notch signaling pathways result in congenital heart defects in humans and other vertebrates3. For example, gata1a4 and tnnt2a5 morpholino oligonucleotides (MO) have been shown to reduce erythropoiesis, while erythropoietin mRNA (EPO)6 and Isoproterenol (ISO)7 increase red blood cells and heart rate respectively, and therefore wall shear stress (WSS). Furthermore, ErbB2 signaling, downstream of Notch, promotes cardiomyocyte proliferation and differentiation to generate contractile force, which in turn activates Notch signaling8,9. It is suggested that shear stress governs Notch signaling driven trabeculation for ventricular development. Currently, there are many studies that attempt to further understand the genetic programming events leading to congenital heart defects (CHD)10,11,12, but very little are investigating how mechanical forces influence the forming heart.
In order to investigate the mechanical forces acting on the endocardium, close observation during the developmental period needs to be implemented. However, it is challenging to obtain good quality images of in vivo beating samples due to the inherence of traditional microscopy13. In order to observe the development over time within a sample, physical sectioning and staining, therefore, need to occur13,14,15. Although confocal microscopy is widely used to image the 3-D structure of samples14,16, these imaging systems&#39; acquisition is still limited by slow scanning speeds.
Light-sheet fluorescence microscopy (LSFM) is a unique imaging technique that allows the visualization of in vivo dynamic events with long working distance13. This technique uses a light-sheet fluorescent microscopy to optically section a sample17. Due to illumination of only a thin sheet of light on the sample, there is a reduction in photo-bleaching and photo toxicity13,18. The large field of view and long working distance allows for large samples to stay intact as they are imaged13,14,17. The low magnification allows for a larger area to be imaged, while the long working distance allows for thicker samples to be imaged without compromising the signal-to-noise ratio. Many groups have used LSFM to image entire embryos17, brains14,18, muscles and hearts19 among other tissues, showing the diverse types of samples that can be imaged.
Although previous research demonstrated reduced hemodynamic shear force by occluding the inflow or outflow tracks of the zebrafish heart, the information is solely qualitative. It results in an abnormal third chamber, diminished cardiac looping, and impaired valve formation20. The 4-D LSFM images give a new perspective into the way the hemodynamic shear forces affect the development of the cardiac tissue. These mechanical forces may activate force-sensitive signaling molecules and induce the formation of the trabecular ridges. Because of the added time aspect of 4-D imaging, one is able to track changes in development in real time, which could lead to new revelations that had gone unnoticed previously. The zebrafish is an ideal model for imaging because scientists can observe an entire vertebrate animal versus only cell-cell interactions. Oxygen can also diffuse through the entire embryo, which allows development to occur without depending on the vascular system, unlike in mammalian development. Even though the zebrafish heart lacks the pulmonary organs, which require a four-chambered heart, there is a large number of cardiac genes that are conserved between zebrafish and humans21.
In this manuscript, we describe how to use light-sheet fluorescence microscopy to image the developing trabeculae in zebrafish hearts under various circumstances. First, injection of gata1a4 or tnnt2a5 MOs were used to lower the blood viscosity, and therefore WSS. The morphology of the heart was then recorded. In a separate group of fish, we increased the WSS by administering EPO mRNA6 or isoproterenol7 and observed the results. We also conducted a cell study with different pulsatile or oscillatory flow rates. After imaging each group, we found that WSS sensed by the endocardium via Notch signaling initiates trabeculation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Clontech Hifi PCR pre-mix&#160;</td>
			<td>Takara&#160;</td>
			<td>639298</td>
			<td>PCR mastermix 
			1.1.1.1, 1.1.1.2, 1.1.1.5, 1.1.2.1, 3.1.4</td>
		</tr>
		<tr>
			<td>Human Nrg1 cDNA</td>
			<td>Gift from William Talbot, Stanford University, Stanford, California, USA</td>
			<td>N/A</td>
			<td>Used for trabeculation rescue 
			1.1.1.3, 1.1.1.4, 1.1.2.1</td>
		</tr>
		<tr>
			<td>CFX Connect&#8482; Real-Time PCR Detection System</td>
			<td>Bio-Rad</td>
			<td>1855201</td>
			<td>PCR Machine 
			1.1.1.5, 1.1.1.6, 1.1.2.2, 1.1.3.2</td>
		</tr>
		<tr>
			<td>pCS2+</td>
			<td>GE Health</td>
			<td></td>
			<td>Plasmid used to synthesize mRNA 
			1.1.2.1, 1.1.2.4, 1.1.2.5</td>
		</tr>
		<tr>
			<td>Nucleospin purification kit&#160;&#160;</td>
			<td>Clontech</td>
			<td>740609.25</td>
			<td>DNA Purification 
			1.1.2.3, 1.1.2.4, 1.1.6.2</td>
		</tr>
		<tr>
			<td>T4 DNA ligase&#160;</td>
			<td>Clontech</td>
			<td>2011A</td>
			<td>PCR Ligation solution 
			1.1.2.5</td>
		</tr>
		<tr>
			<td>Stellar competent cells</td>
			<td>Clontech</td>
			<td>636763</td>
			<td>E. coli cells used for transformation 
			1.1.2.6, 1.1.3.1, 1.1.3.2</td>
		</tr>
		<tr>
			<td>Lipofectamine 2000 transfection reagent</td>
			<td>Life Technologies</td>
			<td>11668027</td>
			<td>Transfection reagent 
			1.1.4</td>
		</tr>
		<tr>
			<td>mMessage SP6 kit</td>
			<td>Invitrogen</td>
			<td>AM1340</td>
			<td>Kit used to synthesize mRNA 
			1.1.6.3</td>
		</tr>
		<tr>
			<td>Aurum Total RNA Mini Kit</td>
			<td>Bio-Rad</td>
			<td>7326820</td>
			<td>Purifies RNA&#160; 
			1.1.6.4, 3.1.2</td>
		</tr>
		<tr>
			<td>GeneTools 4.3.8</td>
			<td>GeneTools</td>
			<td>N/A</td>
			<td>Software for primer design 
			1.2.1, 3.1.3</td>
		</tr>
		<tr>
			<td>EPO cDNA</td>
			<td>Creative Biogene</td>
			<td>CDFH006026</td>
			<td>Increases WSS 
			1.2.2, 1.2.3, 1.1.7</td>
		</tr>
		<tr>
			<td>AG1478</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>T4182</td>
			<td>ErbB inhibitor 
			1.3.1</td>
		</tr>
		<tr>
			<td>E3 medium</td>
			<td></td>
			<td></td>
			<td>To grow embryos 
			1.3.1, 1.3.2, 5.1.5</td>
		</tr>
		<tr>
			<td>DAPT</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>D5942</td>
			<td>&#947;-secretase inhibitor 
			1.3.2</td>
		</tr>
		<tr>
			<td>Agarose&#160;</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>A9539</td>
			<td>Used for mounting embryos 
			2.1.1.1</td>
		</tr>
		<tr>
			<td>ORCA-Flash4.0 LT&#160;Digital CMOS camera</td>
			<td>Hamamatsu Photonics</td>
			<td>C11440-42U</td>
			<td>Used to capture Images 
			2.1.1.2, 2.1.1.3</td>
		</tr>
		<tr>
			<td>Amira Software</td>
			<td>FEI Software</td>
			<td>N/A</td>
			<td>Visualized and Analysed images into 3D, and 4D 
			2.1.5.1.1-2.1.5.2.8</td>
		</tr>
		<tr>
			<td>Tricaone mesylate&#160;</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>886-86-2</td>
			<td>Used to humanely sedated or sacrifice embryos 
			3.1.1</td>
		</tr>
		<tr>
			<td>iScript cDNA Synthesis Kit</td>
			<td>Bio-Rad</td>
			<td>1708890</td>
			<td>Synthesizes cDNA 
			3.1.2</td>
		</tr>
		<tr>
			<td>Eppendorf 5424 microcentrifuge</td>
			<td>Eppendorf</td>
			<td>05-400-005</td>
			<td>Microcentrifuge 
			4.1.1.3</td>
		</tr>
		<tr>
			<td>GI254023X</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>260264-93-5</td>
			<td>ADAM10 inhibitor 
			4.1.2, 4.1.3&#160;</td>
		</tr>
		<tr>
			<td>Isoprenaline hydrochloride</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>I5627</td>
			<td>Isoproterenol increases WSS 
			5.1.5</td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>Mathworks</td>
			<td>N/A</td>
			<td>Cardiac mechanics analysis</td>
		</tr>
	</tbody>
</table>

light-sheet fluorescence microscopy to capture 4-dimensional images of the effects of modulating shear stress on the developing zebrafish heart

The hemodynamic forces experienced by the heart influence cardiac development, especially trabeculation, which forms a network of branching outgrowths from the myocardium. Genetic program defects in the Notch signaling cascade are involved in ventricular defects such as Left Ventricular Non-Compaction Cardiomyopathy or Hypoplastic Left Heart Syndrome. Using this protocol, it can be determined that shear stress driven trabeculation and Notch signaling are related to one another. Using Light-sheet Fluorescence Microscopy, visualization of the developing zebrafish heart was possible. In this manuscript, it was assessed whether hemodynamic forces modulate the initiation of trabeculation via Notch signaling and thus, influence contractile function occurs. For qualitative and quantitative shear stress analysis, 4-D (3-D+time) images were acquired during zebrafish cardiac morphogenesis, and integrated light-sheet fluorescence microscopy with 4-D synchronization captured the ventricular motion. Blood viscosity was reduced via gata1a-morpholino oligonucleotides (MO) micro-injection to decrease shear stress, thereby, down-regulating Notch signaling and attenuating trabeculation. Co-injection of Nrg1 mRNA with gata1a MO rescued Notch-related genes to restore trabeculation. To confirm shear stress driven Notch signaling influences trabeculation, cardiomyocyte contraction was further arrested via tnnt2a-MO to reduce hemodynamic forces, thereby, down-regulating Notch target genes to develop a non-trabeculated myocardium. Finally, corroboration of the expression patterns of shear stress-responsive Notch genes was conducted by subjecting endothelial cells to pulsatile flow. Thus, the 4-D light-sheet microscopy uncovered hemodynamic forces underlying Notch signaling and trabeculation with clinical relevance to non-compaction cardiomyopathy.

LSFM was used in this manuscript in order to acquire high-resolution 2-D and 3-D pictures. As seen in Figure 1A and 1B, the illumination lens directs the light sheet at the sample. Because of the thinness of the light sheet, only a single plane is illuminated. The detection lens is positioned perpendicular to the illumination lens and is focused on the illuminated plane (Figure 1B). The light sheet from the illum...

Watch this Scientific Journal Video about Light-sheet Fluorescence Microscopy to Capture 4-Dimensional Images of the Effects of Modulating Shear Stress on the Developing Zebrafish Heart at JoVE.com

Light-sheet Fluorescence Microscopy to Capture 4-Dimensional Images of the Effects of Modulating Shear Stress on the Developing Zebrafish Heart

Here, we present a protocol to visualize developing hearts in zebrafish in 4-Dimensions (4-D). 4-D imaging, via light-sheet fluorescence microscopy (LSFM), takes 3-Dimensional (3-D) images over time, to reconstruct developing hearts. We show qualitatively and quantitatively that shear stress activates endocardial Notch signaling during chamber development, which promotes cardiac trabeculation.

The hemodynamic forces experienced by the heart influence cardiac development, especially trabeculation, which forms a network of branching outgrowths ...

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