title: 4-Dimensional light-sheet microscopy to elucidate shear stress modulation of cardiac trabeculation.
abstract: Hemodynamic shear forces are intimately linked with cardiac development, during which trabeculae form a network of branching outgrowths from the myocardium. Mutations that alter Notch signaling also result in trabeculation defects. Here, we assessed whether shear stress modulates trabeculation to influence contractile function. Specifically, we acquired 4D (3D + time) images with light sheets by selective plane illumination microscopy (SPIM) for rapid scanning and deep axial penetration during zebrafish morphogenesis. Reduction of blood viscosity via gata1a morpholino oligonucleotides (MO) reduced shear stress, resulting in downregulation of Notch signaling and attenuation of trabeculation. Arrest of cardiomyocyte contraction either by troponin T type 2a (tnnt2a) MO or in weak atriumm58 (wea) mutants resulted in reduced shear stress and downregulation of Notch signaling and trabeculation. Integrating 4D SPIM imaging with synchronization algorithm demonstrated that coinjection of neuregulin1 mRNA with gata1 MO rescued trabeculation to restore contractile function in association with upregulation of Notch-related genes. Crossbreeding of Tg(flk:mCherry) fish, which allows visualization of the vascular system with the Tg(tp1:gfp) Notch reporter line, revealed that shear stress-mediated Notch activation localizes to the endocardium. Deleting endocardium via the clochesk4 mutants downregulated Notch signaling, resulting in nontrabeculated ventricle. Subjecting endothelial cells to pulsatile flow in the presence of the ADAM10 inhibitor corroborated shear stress-activated Notch signaling to modulate trabeculation.
authors.forename: Juhyun
authors.initials: J
authors.lastname: Lee
authors.forename: Peng
authors.initials: P
authors.lastname: Fei
authors.forename: René R Sevag
authors.initials: RR
authors.lastname: Packard
authors.forename: Hanul
authors.initials: H
authors.lastname: Kang
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
authors.forename: Kyung In
authors.initials: KI
authors.lastname: Baek
authors.forename: Nelson
authors.initials: N
authors.lastname: Jen
authors.forename: Junjie
authors.initials: J
authors.lastname: Chen
authors.forename: Hilary
authors.initials: H
authors.lastname: Yen
authors.forename: C-C Jay
authors.initials: CC
authors.lastname: Kuo
authors.forename: Neil C
authors.initials: NC
authors.lastname: Chi
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Ho
authors.forename: Rongsong
authors.initials: R
authors.lastname: Li
authors.forename: Tzung K
authors.initials: TK
authors.lastname: Hsiai
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D006325:Heart Atria / Q000196:embryology; D008856:Microscopy, Fluorescence / Q000379:methods; D009200:Myocardial Contraction / Q000502:physiology*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D020890:Neuregulin-1 / Q000235:genetics / Q000378:metabolism; D038081:Organogenesis / Q000502:physiology*; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism; D033081:Shear Strength; D015398:Signal Transduction / Q000502:physiology*; D020107:Troponin T / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020890:Neuregulin-1; D051880:Receptors, Notch; D020107:Troponin T; D029961:Zebrafish Proteins; C480681:tnnt2a protein, zebrafish