We thank the members of the Vermot lab for discussions and comments on the protocol. We are grateful to all the staff members of the Imperial College London fish facility. This project has received funding from the European Research Council (ERC) under the European Union&#39;s Horizon 2020 research and innovation program: GA N&#176;682939, Additional Ventures (award number 1019496), the MRC (MR/X019837/1) and the BBSRC (BB/Y00566X/1). CV-P was supported by a Bioengineering Departmental Scholarship (Imperial College London). HF was supported by the JSPS KAKENHI (23H04726 and 24K02207), the JST FOREST program (23719210), the Uehara Memorial Foundation, the Cell Science Research Foundation, the Takeda Medical Research Foundation, and the Novartis Research Foundation.

The procedures for working with zebrafish embryos described in this protocol adhere to the European directive 2010/63/EU and Home Office guidelines under the project licence PP6020928.
1. Obtaining zebrafish embryos for bead grafting
<ol>
	<li>Cross the relevant zebrafish line and grow the embryos in Danieau&#39;s medium at 28.5 &#176;C. For more detailed instructions on crossing zebrafish lines, refer to the JoVE Science Education Database27.</li>
	<...

In Vivo Mechanotransduction Study Using Magnetic Beads in the Zebrafish Heart

<ol>
	<li>Streisinger, G., Walker, C., Dower, N., Knauber, D., Singer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+clones+of+homozygous+diploid+zebra+fish+(Brachydanio+rerio).">Production of clones of homozygous diploid zebra fish (Brachydanio rerio).</a> Nature. 291 (5813), 293-296 (1981).</li><li>Tu, S., Chi, N. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+models+in+cardiac+development+and+congenital+heart+birth+defects.">Zebrafish models in cardiac development and congenital heart birth defects.</a> Differentiation. 84 (1), 4-16 (2012).</li><li>Stainier, D. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+genetics+and+vertebrate+heart+formation.">Zebrafish genetics and vertebrate heart formation.</a> Nat Rev Genet. 2 (1), 39-48 (2001).</li><li>Brown, D. R., Samsa, L. A., Qian, L., Liu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+the+study+of+heart+development+and+disease+using+zebrafish.">Advances in the study of heart development and disease using zebrafish.</a> J Cardiovasc Dev Dis. 3 (2), 13 (2016).</li><li>Hoo, J. Y., Kumari, Y., Shaikh, M. F., Hue, S. M., Goh, B. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish:+A+versatile+animal+model+for+fertility+research.">Zebrafish: A versatile animal model for fertility research.</a> Biomed Res Int. 2016 (2016), 9732780 (2016).</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> Cardiovasc Res. 91 (2), 279-288 (2011).</li><li>Briggs, J. P. <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:+a+new+model+organism+for+integrative+physiology.">The zebrafish: a new model organism for integrative physiology.</a> Am J Physiol Regul Integr Comp Physiol. 282 (1), R3-R9 (2002).</li><li>Veldman, M. B., Lin, S. <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+developmental+model+organism+for+pediatric+research.">Zebrafish as a developmental model organism for pediatric research.</a> Pediatr Res. 64 (5), 470-476 (2008).</li><li>Duchemin, A. L., Vignes, H., Vermot, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanically+activated+piezo+channels+modulate+outflow+tract+valve+development+through+the+Yap1+and+Klf2-Notch+signaling+axis.">Mechanically activated piezo channels modulate outflow tract valve development through the Yap1 and Klf2-Notch signaling axis.</a> Elife. 8, e44706 (2019).</li><li>Vignes, H., 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=Extracellular+mechanical+forces+drive+endocardial+cell+volume+decrease+during+zebrafish+cardiac+valve+morphogenesis.">Extracellular mechanical forces drive endocardial cell volume decrease during zebrafish cardiac valve morphogenesis.</a> Dev Cell. 57 (5), 598-609.e595 (2022).</li><li>Steed, 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=klf2a+couples+mechanotransduction+and+zebrafish+valve+morphogenesis+through+fibronectin+synthesis.">klf2a couples mechanotransduction and zebrafish valve morphogenesis through fibronectin synthesis.</a> Nat Commun. 7, 11646 (2016).</li><li>Chow, R. 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=Cardiac+forces+regulate+zebrafish+heart+valve+delamination+by+modulating+Nfat+signaling.">Cardiac forces regulate zebrafish heart valve delamination by modulating Nfat signaling.</a> PLoS Biol. 20 (1), e3001505 (2022).</li><li>Fukui, H., 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=Bioelectric+signaling+and+the+control+of+cardiac+cell+identity+in+response+to+mechanical+forces.">Bioelectric signaling and the control of cardiac cell identity in response to mechanical forces.</a> Science. 374 (6565), 351-354 (2021).</li><li>Vignes, H., Vagena-Pantoula, C., Vermot, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+control+of+tissue+shape:+Cell-extrinsic+and+-intrinsic+mechanisms+join+forces+to+regulate+morphogenesis.">Mechanical control of tissue shape: Cell-extrinsic and -intrinsic mechanisms join forces to regulate morphogenesis.</a> Semin Cell Dev Biol. 130, 45-55 (2022).</li><li>Juan, 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=Multiple+pkd+and+piezo+gene+family+members+are+required+for+atrioventricular+valve+formation.">Multiple pkd and piezo gene family members are required for atrioventricular valve formation.</a> Nat Commun. 14 (1), 214 (2023).</li><li>Juan, 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=Control+of+cardiac+contractions+using+Cre-lox+and+degron+strategies+in+zebrafish.">Control of cardiac contractions using Cre-lox and degron strategies in zebrafish.</a> Proc Natl Acad Sci U S A. 121 (3), e2309842121 (2024).</li><li>Duchemin, A. L., Vignes, H., Vermot, J., Chow, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanotransduction+in+cardiovascular+morphogenesis+and+tissue+engineering.">Mechanotransduction in cardiovascular morphogenesis and tissue engineering.</a> Curr Opin Genet Dev. 57, 106-116 (2019).</li><li>Kalogirou, S., 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+flow+dynamics+regulate+atrioventricular+valve+morphogenesis.">Intracardiac flow dynamics regulate atrioventricular valve morphogenesis.</a> Cardiovasc Res. 104 (1), 49-60 (2014).</li><li>da Silva, A. 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=egr3+is+a+mechanosensitive+transcription+factor+gene+required+for+cardiac+valve+morphogenesis.">egr3 is a mechanosensitive transcription factor gene required for cardiac valve morphogenesis.</a> Sci Adv. 10 (20), eadl0633 (2024).</li><li>Bartman, 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=Early+myocardial+function+affects+endocardial+cushion+development+in+zebrafish.">Early myocardial function affects endocardial cushion development in zebrafish.</a> PLoS Biol. 2 (5), E129 (2004).</li><li>Steed, E., Boselli, F., Vermot, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamics+driven+cardiac+valve+morphogenesis.">Hemodynamics driven cardiac valve morphogenesis.</a> Biochim Biophys Acta. 1863 (7 Pt B), 1760-1766 (2016).</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), e1000246 (2009).</li><li>B&#228;ck, M., Gasser, T. C., Michel, J. B., Caligiuri, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanical+factors+in+the+biology+of+aortic+wall+and+aortic+valve+diseases.">Biomechanical factors in the biology of aortic wall and aortic valve diseases.</a> Cardiovasc Res. 99 (2), 232-241 (2013).</li><li>Hahn, C., Schwartz, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanotransduction+in+vascular+physiology+and+atherogenesis.">Mechanotransduction in vascular physiology and atherogenesis.</a> Nat Rev Mol Cell Biol. 10 (1), 53-62 (2009).</li><li>Boselli, F., Steed, E., Freund, J. B., Vermot, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anisotropic+shear+stress+patterns+predict+the+orientation+of+convergent+tissue+movements+in+the+embryonic+heart.">Anisotropic shear stress patterns predict the orientation of convergent tissue movements in the embryonic heart.</a> Development. 144 (23), 4322-4327 (2017).</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>JoVE Science Education database. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biology+II:+Mouse,+zebrafish,+and+chick.+Zebrafish+breeding+and+embryo+handling.">Biology II: Mouse, zebrafish, and chick. Zebrafish breeding and embryo handling.</a> JoVE. , (2023).</li><li>Arrenberg, A. B., Stainier, D. Y., Baier, H., Huisken, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optogenetic+control+of+cardiac+function.">Optogenetic control of cardiac function.</a> Science. 330 (6006), 971-974 (2010).</li></ol>

Critical steps in the protocol and troubleshooting
Mounting of zebrafish embryos
The quantity of agarose used to mount the embryos is important. The dome formed should not be excessively large, as this can hinder the manipulation of the bead from the surface to the embryos. Conversely, it should not be too small; having multiple beads atop the agarose, positioned close to the embryos and their yolk, can cause confusion. A v...

Since its introduction in the late 1970s1, the zebrafish (Danio rerio) has emerged as a powerful model system for studying the intricacies of cardiac development and congenital heart disorders. Unlike most vertebrates, including mouse and chick embryos, which rely on a functional cardiovascular system and cannot survive early heart defects, zebrafish provide a unique advantage by enabling the investigation of severe heart phenotypes. This is due to their small size, which facilitates sufficient oxygen supply through passive diffusion, allowing survival even in the absence of heart contraction and active blood circulation2,3,4. Furthermore, among the many significant features of zebrafish is the optical transparency of their embryos, which enables non-invasive monitoring of the developing heart5,6,7,8.
Mechanical forces continuously provide feedback to the heart valve morphogenetic programs9,10,11,12,13,14,15,16,17,18,19,20,21,22, and aberrant blood flow is widely acknowledged as a shared factor in various cardiovascular disorders23,24. In zebrafish, cardiac valve development relies on heart contraction and mechanical forces generated by the beating heart. Multiple zebrafish mutants have demonstrated the significance of heart-generated mechanical stimuli in valvulogenesis. Remarkably, the complete absence of heart contraction and, consequently, blood flow due to mutations of cardiac troponin T (tnnt2) in silent heart (sih) mutants results in the absence of tissue convergence and endocardial cell (EdC) clustering during early morphogenetic stages25.
Intracardiac hemodynamics and mechanical forces generated by the blood flow emerge as fundamental epigenetic components shaping the development of the zebrafish embryonic heart. Numerous studies suggest that proper cardiac morphogenesis in zebrafish requires distinct flow stimuli, and deviations from these physiological patterns lead to heart valve defects10,13,14,22,26. Here, we describe an effective method, adapted from Fukui et al.13, to manipulate mechanical forces in vivo by grafting a 30 &#181;m to 60 &#181;m diameter magnetic bead within the developing zebrafish beating heart. The technique involves microsurgical insertion of a bead into the cardiac lumen of anesthetized larvae without perturbing heart function. The presence of the bead leads to the amplification of the mechanical forces experienced by EdCs, directly triggering mechanical stimulus-dependent calcium influx13. This approach enables the investigation of mechanotransduction pathways that regulate heart morphogenesis and offers a means to deepen our understanding of the role of mechanical forces in valve formation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Materials</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Essential equipment for zebrafish raising, breeding, and embryo collection</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glass-bottom dish (35 mm x 15&#160;mm)</td>
			<td>VWR International</td>
			<td>734-2905</td>
			<td></td>
		</tr>
		<tr>
			<td>Heat block</td>
			<td>Eppendorf</td>
			<td>EP5382000031</td>
			<td>Eppendorf ThermoMixer C</td>
		</tr>
		<tr>
			<td>Jewelers forceps</td>
			<td>Sigma-Aldrich</td>
			<td>F6521-1EA</td>
			<td>Dumont No. 5, L 4 1/4 in., Inox alloy</td>
		</tr>
		<tr>
			<td>Microcentrifuge tubes 2 mL</td>
			<td>Eppendorf</td>
			<td>30120094</td>
			<td></td>
		</tr>
		<tr>
			<td>Pasteur pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4 mg/mL tricaine stock solution</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Danieau&#39;s medium (60x stock solution)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PureCube Glutathione MagBeads</td>
			<td>Cube Biotech</td>
			<td>32201</td>
			<td></td>
		</tr>
		<tr>
			<td>PTU (1-phenyl-2-thiourea)</td>
			<td>Sigma-Aldrich</td>
			<td>P7629</td>
			<td></td>
		</tr>
		<tr>
			<td>UltraPure low melting point agarose</td>
			<td>Invitrogen</td>
			<td>16520-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Danieau&#39;s medium (60x stock solution)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>34.8 g NaCl</td>
			<td>Sigma-Aldrich</td>
			<td>S3014</td>
			<td></td>
		</tr>
		<tr>
			<td>1.6 g KCl</td>
			<td>Sigma-Aldrich</td>
			<td>P9541</td>
			<td></td>
		</tr>
		<tr>
			<td>5.8 g CaCl2&#183;2H2O</td>
			<td>Sigma-Aldrich</td>
			<td>C3306</td>
			<td></td>
		</tr>
		<tr>
			<td>9.78 g MgCl2&#183;6H2O&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>442611-M</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissolve the ingredients in H2O to a final volume of 2 L. Adjust the pH to 7.2 using NaOH, then autoclave.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4 mg/mL tricaine stock solution</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>400 mg of tricaine powder (Ethyl 3-aminobenzoate methanesulfonate salt)</td>
			<td>Sigma-Aldrich</td>
			<td>A5040</td>
			<td></td>
		</tr>
		<tr>
			<td>97.9 mL double-distilled H2O</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2.1 mL 1 M Tris (pH 9)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adjust the pH to 7, then aliquot and store at -20 &#176;C.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

manipulating mechanical forces in the developing zebrafish heart using magnetic beads

Mechanical forces continuously provide feedback to heart valve morphogenetic programs. In zebrafish, cardiac valve development relies on heart contraction and physical stimuli generated by the beating heart. Intracardiac hemodynamics, driven by blood flow, emerge as fundamental information shaping the development of the embryonic heart. Here, we describe an effective method to manipulate mechanical forces in vivo by grafting a 30 &#181;m to 60 &#181;m diameter magnetic bead in the cardiac lumen. The insertion of the bead is conducted through microsurgery in anesthetized larvae without perturbing heart function and enables artificial alteration of the boundary conditions, thereby modifying flow forces in the system. As a result, the presence of the bead amplifies the mechanical forces experienced by endocardial cells and can directly trigger mechanical stimulus-dependent calcium influx. This approach facilitates the investigation of mechanotransduction pathways that govern heart development and can provide insights into the role of mechanical forces in cardiac valve morphogenesis.

Author Spotlight: Understanding Mechanical Forces Involved in Shaping the Zebrafish Heart

Manipulating Mechanical Forces in the Developing Zebrafish Heart Using Magnetic Beads

We focus on understanding how mechanical forces shape the zebrafish heart using advanced imaging techniques. By combining our knowledge of biology, physics, microscopy, and computing, we develop tools for optical imaging and image analysis to study how mechanical stimuli influence the way the cardiovascular system develops. A beating heart generates several type of forces, such as pressure for the shear and contractor force.Although each of these forces has a function in vitro culture systems, it is difficult to separate these parameters in the in vivo heart. By developing our approach, we aim to tackle this challenging task. We have established a novel approach to assess, adapt biological output caused by external force stimulation, and we verified our force spin and constant signal in crosscutting the cardiac cells.As a result this approach enables us to impetrate other aspects of tissue neurogenesis in the world of mechanical biology. This method enables the study of heart function in zebrafish embryo via targeted mechanical stimulation. Unlike genetic, pharmacological, or optogenetic approaches, pit grafting offers a more direct way to influence heart physiology through mechanical means.Pit grafting is viable for examining the roles of mechanical forces and calcium influx in cardiac biological processes. It provides means to deepen our understanding of the mechanical transduction pathways involved in heart development and function.

Examples of successful bead grafting are shown in Figure 3, Video 3, and Video 4. The magnetic bead was correctly positioned within the atrium of the zebrafish heart, allowing for unobstructed blood flow and no observed hemorrhage. Additionally, the heart walls maintained their structural integrity without collapsing (Figure 3 and Video 3). After 24 h, the embryo showed no signs of pericardial edema, further con...

This protocol outlines a method for grafting a magnetic bead into the developing zebrafish heart through microsurgery, enabling the manipulation of mechanical forces in vivo and triggering mechanical stimulus-dependent calcium influx in endocardial cells.

Mechanical forces continuously provide feedback to heart valve morphogenetic programs. In zebrafish, cardiac valve development relies on heart contraction ...

manipulating-mechanical-forces-developing-zebrafish-heart-using

Research

JoVE Journal

Developmental Biology

533 ビュー.  Imperial College London. 私たちは、高度なイメージング技術を用いて、機械的な力がゼブラフィッシュの心臓をどのように形成するかを理解することに焦点を当てています。生物学、物理学、顕微鏡法、コンピューティングの知識を結集して、光学イメージングと画像解析のためのツールを開発し、機械的刺激が心血管系の発達にどのように影響するかを研究していま?...

ビデオ: 著者スポットライト:ゼブラフィッシュの心臓の形成に関与する機械的な力を理解する

This protocol outlines a method for grafting a magnetic bead into the developing zebrafish heart through microsurgery, enabling the manipulation of mechanical forces in vivo and triggering mechanical stimulus-dependent calcium influx in endocardial...

https://cloudfront.jove.com/CDNSource/teasers/67604_b.jpg

mechanical vessel injury in zebrafish embryos

Mechanical Vessel Injury in Zebrafish Embryos

This article describes a method for creating a mechanical vessel injury in zebrafish embryos. This injury model provides a platform for studying hemostasis, injury-related inflammation, and wound healing in an organism ideally suited for real-time microscopy.

biaxial mechanical characterizations of atrioventricular heart valves

Biaxial Mechanical Characterizations of Atrioventricular Heart Valves

This protocol involves characterizations of atrioventricular valve leaflets with force-controlled, displacement-controlled, and stress-relaxation biaxial mechanical testing procedures. Results acquired with this protocol can be used for constitutive model development to simulate the mechanical behavior of functioning valves under a finite element simulation...

intrathoracic injection for the study of adult zebrafish heart

Intrathoracic Injection for the Study of Adult Zebrafish Heart

This method relies on the injection of 0.5&#8722;3 &#956;L of solution into the thorax of adult zebrafish. The procedure efficiently delivers proteins and chemical compounds into the proximity of the zebrafish heart without damaging the organ. The approach is suitable for testing effects of exogenous factors on various tissues of the...

a passive ankle dorsiflexion testing system for an in vivo model of overuse-induced tendinopathy

Author Spotlight: Integrating Mechanical and Biological Analysis in Tendinopathy Research 

This protocol presents a testing system used to induce quantifiable and controlled fatigue injuries in a rat Achilles tendon for an in-vivo model of overuse-induced tendinopathy. The procedure consists of securing the rat's ankle to a joint actuator that performs passive ankle dorsiflexion with a custom-written MATLAB script.

Cyclic Mechanical Loading for Inducing Tendinopathy in Rat Achilles Tendon

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immunostaining of dissected zebrafish embryonic heart

Immunostaining of Dissected Zebrafish Embryonic Heart

A rapid way to conduct immunostaining of zebrafish embryonic heart is described.  Compared to the whole mount immunostaining approach, this method dramatically increases the penetration of the antibodies, which allows obtaining high resolution images that reveal cellular/subcellular structures in the heart within a much reduced processing...

microfabricated post-array-detectors (mpads): an approach to isolate mechanical forces

Microfabricated Post-Array-Detectors mPADs: an Approach to Isolate Mechanical Forces

In this video, we demonstrate how to fabricate and utilize microfabricated post array detectors (mPADs) to assess modulations of cellular...

Microfabricated Post-Array-Detectors (mPADs): an Approach to Isolate Mechanical Forces

epithelial cell infection analyses with shigella

Author Spotlight: Advancements in Understanding and Combatting &lt;em&gt;Shigella&lt;/em&gt; Infections

The present protocol describes infection assays to interrogate Shigella adherence, invasion, and intracellular replication using in vitro epithelial cell...

Protocols for Analyzing &lt;em&gt;Shigella&lt;/em&gt; Infection in Colonic Epithelial Cells

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intrathoracic injection: compound delivery to the adult zebrafish heart

This video describes the technique of delivering compounds into the heart of adult zebrafish by using intrathoracic...

Intrathoracic Injection: Compound Delivery to the Adult Zebrafish Heart

nanoparticle-mediated sirna gene-silencing in adult zebrafish heart

Nanoparticle-mediated siRNA Gene-silencing in Adult Zebrafish Heart

It remains a major challenge to develop conditional gene-knockout or effective gene-knockdown in adult zebrafish organs. Here we report a protocol for performing nanoparticle-mediated siRNA gene-silencing in adult zebrafish heart, thus providing a new loss-of-function method for studying adult organs in zebrafish and other model...

heart dissection in larval, juvenile and adult zebrafish, danio rerio

Heart Dissection in Larval, Juvenile and Adult Zebrafish, Danio rerio

A clear, standardized method for dissection and isolation of the zebrafish heart at multiple developmental stages are described. Annotation and quantification techniques are also...

Heart Dissection in Larval, Juvenile and Adult Zebrafish, Danio rerio

two-photon calcium imaging of forebrain activity in behaving adult zebrafish

Author Spotlight: Advancements in Adult Zebrafish Brain Research 

Here, we present a protocol to perform two-photon calcium imaging in the dorsal forebrain of adult...

Behavior Tracking and Neural Activity Pattern in the Zebrafish Forebrain

tuina manipulation to reduce inflammation and cartilage loss in knee osteoarthritis rats

Author Spotlight: Understanding the Mechanism of Tuina Manipulation in Rats 

We present a protocol for Tuina manipulation performed on plaster-immobilized-induced knee osteoarthritis rats. Based on the preliminary results, it suggested that the efficacy of the method relied on the reduction of inflammation and cartilage...

Standardized Tuina Manipulation for Knee Osteoarthritis in Rats

4d light-sheet imaging of zebrafish cardiac contraction

Author Spotlight: High-Resolution 4D Light-Sheet Imaging and Virtual Reality in Zebrafish for Single-Cell Analysis of Heart Function

This protocol utilizes light-sheet imaging to investigate cardiac contractile function in zebrafish larvae and gain insights into cardiac mechanics through cell tracking and interactive...

Analysis of Zebrafish Cardiac Contraction with Virtual Reality Interaction

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a protocol for using f&#246;rster resonance energy transfer (fret)-force biosensors to measure mechanical forces across the nuclear linc complex

A Protocol for Using F&amp;#246;rster Resonance Energy Transfer (FRET)-force Biosensors to Measure Mechanical Forces across the Nuclear LINC Complex

A number of FRET-based force biosensors have recently been developed, enabling the protein-specific resolution of intracellular force. In this protocol, we demonstrate how one of these sensors, designed for the linker of the nucleoskeleton-cytoskeleton (LINC) complex protein Nesprin-2G can be used to measure actomyosin forces on the nuclear LINC complex.

A Protocol for Using F&#246;rster Resonance Energy Transfer (FRET)-force Biosensors to Measure Mechanical Forces across the Nuclear LINC Complex

probing the roles of physical forces in early chick embryonic morphogenesis

Probing the Roles of Physical Forces in Early Chick Embryonic Morphogenesis

Here, we present a protocol introducing a set of new ex-ovo experiments and physical modeling approaches for studying the mechanics of morphogenesis during early chick embryonic brain...

in vitro culturing technique for studying cellular dynamics in zebrafish scales

Author Spotlight: Advancing Bone Cell Activity Research with Zebrafish Scales 

This protocol offers a method to study cellular dynamics using a simple in vitro culture technique. It provides an opportunity for zebrafish researchers and educators to study cellular processes, such as those related to bone homeostasis and basic cell biology, by visualizing fluorescent nuclei and apoptotic cells within the...

Removing Zebrafish Scales for Culturing and Bone Biology Studies

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a neonatal heterotopic rat heart transplantation model for the study of endothelial-to-mesenchymal transition

Author Spotlight: A Neonatal Heterotopic Rat Heart Transplantation Model for the Study of Endothelial-to-Mesenchymal Transition  

This work presents an animal model of endothelial-to-mesenchymal transition-induced fibrosis, as seen in congenital cardiac defects such as critical aortic stenosis or hypoplastic left heart syndrome, which allows for detailed histological tissue evaluation, the identification of regulatory signaling pathways, and the testing of treatment options.

In Vivo Heart Transplantation to Study Endothelial-to-Mesenchymal Transition

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large-scale zebrafish embryonic heart dissection for transcriptional analysis

Large-scale Zebrafish Embryonic Heart Dissection for Transcriptional Analysis

To analyse cardiac gene expression profiles during zebrafish heart development, total RNA has to be extracted from isolated hearts. Here, we present a protocol for collecting functional/beating hearts by rapid manual dissection from zebrafish embryos to obtain cardiac-specific...

Magnetic Bead Grafting in the Zebrafish Cardiac Lumen for Controlled Force Amplification: Unraveling Mechanotransduction in Heart Valve Development

To begin, place three to six dechorionated embryos in a Petri dish containing Danios medium supplemented with 0.02%tricaine. Once the embryos are anesthetized, transfer them to a 35 by 15 millimeter glass bottom dish with minimal medium. Quickly add 300 to 400 microliters of 1%low melting point agarose containing tricaine to create a dome.Using forceps, position the embryos so they lie straight in contact with the glass with the ventral side facing up. Next, deposit approximately 0.5 microliters of magnetic beads on top of the agarose. Then add a drop of Danios medium containing 0.02%tricaine on top of the agarose and the beads.Based on the sample and heart size, select the appropriate bead and use tweezers to place it on top of the embryo yolk. Create a yolk lesion or hole in the center of the yolk using one arm of the tweezers. Place the bead into the lesion and gently push it anteriorly until it reaches the venous pole.If suction alone is insufficient to move the bead, gently push it toward the atrium, applying enough pressure to guide it into the pericardial cavity. After grafting the magnetic beads into the embryos, add one to two milliliters of Danios medium containing PTU to the glass bottom dish. Then using tweezers, gently break the low melting point agarose and carefully remove the embryos.Finally, using a Pasteur pipette, transfer the embryos to a new Petri dish containing Danios medium with PTU and allow them to recover and develop at 28.5 degrees Celsius. The magnetic bead was correctly positioned within the atrium of the zebrafish heart, allowing for unobstructed blood flow and no observed hemorrhage with the heart walls maintained.