Focal adhesion kinase is required for neural crest cell morphogenesis during mouse cardiovascular development
Ainara Vallejo-Illarramendi, … , Keling Zang, Louis F. Reichardt
Ainara Vallejo-Illarramendi, … , Keling Zang, Louis F. Reichardt
Published July 1, 2009
Citation Information: J Clin Invest. 2009;119(8):2218-2230. https://doi.org/10.1172/JCI38194.
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Focal adhesion kinase is required for neural crest cell morphogenesis during mouse cardiovascular development

Abstract

Neural crest cells (NCCs) participate in the remodeling of the cardiac outflow tract and pharyngeal arch arteries during cardiovascular development. Focal adhesion kinase (FAK) mediates signal transduction by integrin and growth factor receptors, each of which is important for normal cardiovascular development. To investigate the role of FAK in NCC morphogenesis, we deleted it in murine NCCs using Wnt1cre, yielding craniofacial and cardiovascular malformations resembling those observed in individuals with DiGeorge syndrome. In these mice, we observed normal cardiac NCC migration but reduced differentiation into smooth muscle within the aortic arch arteries and impaired cardiac outflow tract rotation, which resulted in a dextroposed aortic root. Moreover, within the conotruncal cushions, Fak-deficient NCCs formed a less organized mesenchyme, with reduced expression of perlecan and semaphorin 3C, and exhibited disorganized F-actin stress fibers within the aorticopulmonary septum. Additionally, absence of Fak resulted in reduced in vivo phosphorylation of Crkl and Erk1/2, components of a signaling pathway essential for NCC development. Consistent with this, both TGF-β and FGF induced FAK and Crkl phosphorylation in control but not Fak-deficient NCCs in vitro. Our results indicate that FAK plays an essential role in cardiac outflow tract development by promoting the activation of molecules such as Crkl and Erk1/2.

Authors

Ainara Vallejo-Illarramendi, Keling Zang, Louis F. Reichardt

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Figure 3

NCC differentiation in the cardiac outflow tract and aortic arch arteries of conditional Fak mutant embryos.

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NCC differentiation in the cardiac outflow tract and aortic arch arterie...
(A–F) Frontal sections of outflow tracts (OFT) stained for GFP and SMA. (A and B) At E11, NCCs expressing GFP are able to differentiate into smooth muscle in mutant embryos and control littermates (arrowheads). (C and D) At E12.5, NCCs (blue) differentiate into smooth muscle cells in the aorticopulmonary septum (arrowheads), even in mutants with abnormal aorticopulmonary communication. (E and F) Anterior sections from same embryos as in C and D, showing that myocardialization of the outflow tract in mutants is not altered (asterisks). At this stage, SMA stains for both smooth muscle and myocardium. (G) E11 embryo showing planes of sections for A and B (x) and I–L (y). (H) Western blot of E11 branchial arches (n = 3 embryos pooled), showing decreased SMA levels in mutants compared with control littermates. (I–V) Frontal sections through the pharyngeal arch arteries (PAA) stained for GFP, SMA, TUNEL, and DAPI. (I and J) At E11, NCCs colonize the third, fourth, and sixth pharyngeal arch arteries (arrows) in mutant and control littermates. (K and L) Reduction of SMA staining in mutant pharyngeal arch arteries (arrows) was not associated with increased NCC death. (M–V) E12.5 frontal sections showing preductal aortic arch region defective for NCC differentiation in a mutant (arrow). N–Q and S–V show higher magnification pictures from the boxed regions in M and R, respectively. O and T were stained with X-gal, and Q and V were stained with DAPI. p, pulmonary artery. Scale bars: 100 μm (A, B, E, F, M, and R); 50 μm (I–L, N–Q, and S–V); 25 μm (C and D).