Large-scale reprogramming of cranial neural crest gene expression by retinoic acid exposure.
Although retinoic acid (RA), the active form of vitamin A, is required for normal embryonic growth and development, it is also a powerful teratogen. Infants born to mothers exposed to retinoids during pregnancy have a 25-fold increased risk for malformations, nearly exclusively of cranial neural crest-derived tissues. To characterize neural crest cell responses to RA, we exposed murine crest cultures to teratogenic levels of RA and subjected their RNA to microarray-based gene expression profile analysis using Affymetrix MG-U74Av2 GeneChips. RNAs were isolated from independent cultures treated with 10(-6) M RA for 6, 12, 24, or 48 h. Statistical analyses of gene expression profile data facilitated identification of the 205 top-ranked differentially regulated genes whose expression was reproducibly changed by RA over time. Cluster analyses of these genes across the independently treated sample series revealed distinctive kinetic patterns of altered gene expression. The largest group was transiently affected within the first 6 h of exposure, representing early responding genes. Group 2 showed sustained induction by RA over all times, whereas group 3 was characterized by the suppression of a time-dependent expression increase normally seen in untreated cells. Additional patterns demonstrated time-dependent increased or decreased expression among genes not normally regulated to a significant extent. Gene function analysis revealed that more than one-third of all RA-regulated genes were associated with developmental regulation, including both canonical and noncanonical Wnt signaling pathways. Multiple genes associated with cell adhesion and cell cycle regulation, recognized targets for the biological effects of RA, were also affected. Taken together, these results support the hypothesis that the teratogenic effects of RA derive from reprogramming gene expression of a host of genes, which play critical roles during embryonic development regulating pathways that determine subsequent differentiation of cranial neural crest cells.
Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
Sarah S
SS
Williams
John P
JP
Mear
Hung-Chi
HC
Liang
S Steven
SS
Potter
Bruce J
BJ
Aronow
Melissa C
MC
Colbert
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D020209:Cranial Nerve Injuries / Q000139:chemically induced; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods / Q000706:statistics & numerical data; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D005796:Genes / Q000187:drug effects / Q000502:physiology; D017781:Genes, Immediate-Early / Q000187:drug effects / Q000235:genetics; D051379:Mice; D009432:Neural Crest / Q000737:chemistry* / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods / Q000706:statistics & numerical data; D013489:Suppression, Genetic / Q000187:drug effects; D013997:Time Factors; D014212:Tretinoin / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
D014212:Tretinoin