TY - JOUR
T1 - Retinoic acid deficiency alters second heart field formation
AU - Ryckebusch, Lucile
AU - Wang, Zengxin
AU - Bertrand, Nicolas
AU - Lin, Song Chang
AU - Chi, Xuan
AU - Schwartz, Robert
AU - Zaffran, Stéphane
AU - Niederreither, Karen
PY - 2008/2/26
Y1 - 2008/2/26
N2 - Retinoic acid (RA), the active derivative of vitamin A, has been implicated in various steps of cardiovascular development. The retinaldehyde dehydrogenase 2 (RALDH2) enzyme catalyzes the second oxidative step in RA biosynthesis and its loss of function creates a severe embryonic RA deficiency. Raldh2 -/- knockout embryos fail to undergo heart looping and have impaired atrial and sinus venosus development. To understand the mechanism(s) producing these changes, we examined the contribution of the second heart field (SHF) to pharyngeal mesoderm, atria, and outflow tract in Raldh2-/- embryos. RA deficiency alters SHF gene expression in two ways. First, Raldh2 -/- embryos exhibited a posterior expansion of anterior markers of the SHF, including Tbx1, Fgf8, and the Mlc1v-nlacZ-24/Fgf10 reporter transgene as well as of Islet1. This occurred at early somite stages, when cardiac defects became irreversible in an avian vitamin A-deficiency model, indicating that endogenous RA is required to restrict the SHF posteriorly. Explant studies showed that this expanded progenitor population cannot differentiate properly. Second, RA up-regulated cardiac Bmp expression levels at the looping stage. The contribution of the SHF to both inflow and outflow poles was perturbed under RA deficiency, creating a disorganization of the heart tube. We also investigated genetic cross-talk between Nkx2.5 and RA signaling by generating double mutant mice. Strikingly, Nkx2.5 deficiency was able to rescue molecular defects in the posterior region of the Raldh2-/- mutant heart, in a gene dosage-dependent manner.
AB - Retinoic acid (RA), the active derivative of vitamin A, has been implicated in various steps of cardiovascular development. The retinaldehyde dehydrogenase 2 (RALDH2) enzyme catalyzes the second oxidative step in RA biosynthesis and its loss of function creates a severe embryonic RA deficiency. Raldh2 -/- knockout embryos fail to undergo heart looping and have impaired atrial and sinus venosus development. To understand the mechanism(s) producing these changes, we examined the contribution of the second heart field (SHF) to pharyngeal mesoderm, atria, and outflow tract in Raldh2-/- embryos. RA deficiency alters SHF gene expression in two ways. First, Raldh2 -/- embryos exhibited a posterior expansion of anterior markers of the SHF, including Tbx1, Fgf8, and the Mlc1v-nlacZ-24/Fgf10 reporter transgene as well as of Islet1. This occurred at early somite stages, when cardiac defects became irreversible in an avian vitamin A-deficiency model, indicating that endogenous RA is required to restrict the SHF posteriorly. Explant studies showed that this expanded progenitor population cannot differentiate properly. Second, RA up-regulated cardiac Bmp expression levels at the looping stage. The contribution of the SHF to both inflow and outflow poles was perturbed under RA deficiency, creating a disorganization of the heart tube. We also investigated genetic cross-talk between Nkx2.5 and RA signaling by generating double mutant mice. Strikingly, Nkx2.5 deficiency was able to rescue molecular defects in the posterior region of the Raldh2-/- mutant heart, in a gene dosage-dependent manner.
KW - FGF8
KW - Heart development
KW - Nkx2.5
KW - Retinaldehyde dehydrogenase 2
KW - Retinoids
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U2 - 10.1073/pnas.0712344105
DO - 10.1073/pnas.0712344105
M3 - Article
C2 - 18287057
AN - SCOPUS:42949174176
SN - 0027-8424
VL - 105
SP - 2913
EP - 2918
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 8
ER -