title: Folic acid rescue of ATRA-induced cleft palate by restoring the TGF-β signal and inhibiting apoptosis.
abstract: BACKGROUND
  Cleft palate is a frequent congenital malformation with a heterogeneous etiology, for which folic acid (FA) supplementation has a protective effect. To gain more insight into the molecular pathways affected by FA, TGF-β signaling and apoptosis in mouse embryonic palatal mesenchymal (MEPM) cells of all-trans retinoic acid (ATRA)-induced cleft palate in organ culture were tested.
  
  
  METHODS
  C57BL/6J mice embryonic palates were explanted on embryonic day 14 and cultured in DMEM/F12 medium with or without ATRA or FA for 72 h. The palatal fusion was examined by light microscopy. Immunohistochemistry was used to detect TGFβ3/TGF receptor II and caspase 9 in MEPM cells. TUNEL was used to detect apoptosis.
  
  
  RESULTS
  Similar to development in vivo, palatal development and fusion were normal in control medium. ATRA inhibited palatal development and induced cleft palate, which can be rescued by FA. A higher apoptosis rate and caspase-9 in MEPM cells were detected in the ATRA group than in the control or the ATRA+FA group. Compared with the control or the ATRA+FA group, ATRA had little effect on TGF-β3 in MEPM cells but significantly inhibited TGF-β receptor II.
  
  
  CONCLUSIONS
  Folic acid can rescue the cultured palates to continue developing and fusing that were inhibited and resulted in cleft palate by ATRA. Apoptosis and TGFβ signaling in MEPM cells were involved in folic acid rescued ATRA-induced cleft palate.
authors.affiliation: Department of Oral and Maxillofacial surgery, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Zhaoyou
authors.initials: Z
authors.lastname: Yao
authors.forename: Dan
authors.initials: D
authors.lastname: Chen
authors.forename: Anxun
authors.initials: A
authors.lastname: Wang
authors.forename: Xueqiang
authors.initials: X
authors.lastname: Ding
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Ling
authors.forename: Qianting
authors.initials: Q
authors.lastname: He
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053453:Caspase 9 / Q000378:metabolism; D002478:Cells, Cultured; D002972:Cleft Palate / Q000139:chemically induced / Q000196:embryology* / Q000517:prevention & control*; D005492:Folic Acid / Q000494:pharmacology / Q000627:therapeutic use*; D051379:Mice; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013723:Teratogens; D053782:Transforming Growth Factor beta3 / Q000502:physiology*; D014212:Tretinoin; D014803:Vitamin B Complex / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D018125:Receptors, Transforming Growth Factor beta; D013723:Teratogens; D053782:Transforming Growth Factor beta3; D014803:Vitamin B Complex; D014212:Tretinoin; D005492:Folic Acid; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D053453:Caspase 9