Platelet-derived growth factor C plays a role in the branchial arch malformations induced by retinoic acid.
BACKGROUND
All-trans-retinoic acid (RA) can produce branchial arch abnormalities in postimplantation rodent embryos cultured in vitro. Platelet-derived growth factor C (PDGF-C) was recently identified as a member of the PDGF ligand family. Many members of the PDGF family are essential for branchial arch morphogenesis and can be regulated by RA. The roles of PDGF-C in branchial arch malformations induced by RA and possible mechanisms were investigated.


METHODS
In whole embryo culture (WEC), mouse embryos were exposed to RA at 0, 0.1, 0.4, 1.0, or 10.0 microM, PDGF-C at 25, 50, or 75 ng/mL, or PDGF-C at 25, 50, or 75 ng/mL containing 0.4 microM RA. After 48 h of culture, mouse embryos were examined for dysmorphogenesis, and whole-mount immunohistochemistry was applied to PDGF-C. In explant cultures, explants were exposed to the same doses of RA and PDGF-C as WEC. Semiquantitative RT-PCR, zymography, and reverse zymography were used to evaluate the expressions and activities of matrix metalloproteinase (MMP)-2, MMP-14, and tissue inhibitor of metalloproteinase (TIMP)-2.


RESULTS
PDGF-C was reduced by RA, and exogenous PDGF-C rescued the branchial arch malformations induced by RA. Moreover, PDGF-C prevented RA-induced inhibition of the migratory ability of mesenchymal cells in the first branchial arch, by regulating the expressions of MMP-2, MMP-14, and TIPM-2.


CONCLUSIONS
Our results suggest that RA exposure reduces the expression of PDGF-C. The branchial arch malformations resulting from fetal RA exposure are caused at least partially by loss of PDGF-C and subsequent misregulations of the expressions of MMP-2, MMP-14, and TIMP-2.
Han
Jing
J
Department of Food Science and Nutrition, School of Public Health, Peking University, Beijing, China.
Li
Li
L
Zhang
Zhaofeng
Z
Xiao
Ying
Y
Lin
Jiuxiang
J
Zheng
Liping
L
Li
Yong
Y
D000818:Animals; D001934:Branchial Region / Q000002:abnormalities* / Q000187:drug effects / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D046149:Embryo Culture Techniques; D004622:Embryo, Mammalian / Q000187:drug effects; D005260:Female; D007150:Immunohistochemistry; D008222:Lymphokines / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D014212:Tretinoin / Q000633:toxicity*
D008222:Lymphokines; D010982:Platelet-Derived Growth Factor; C411423:platelet-derived growth factor C; D019716:Tissue Inhibitor of Metalloproteinase-2; D014212:Tretinoin; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14