Cigarette smoke induces proteasomal-mediated degradation of DNA methyltransferases and methyl CpG-/CpG domain-binding proteins in embryonic orofacial cells.
Orofacial clefts, the most prevalent of developmental anomalies, occur with a frequency of 1 in 700 live births. Maternal cigarette smoking during pregnancy represents a risk factor for having a child with a cleft lip and/or cleft palate. Using primary cultures of first branchial arch-derived cells (1-BA cells), which contribute to the formation of the lip and palate, the present study addressed the hypothesis that components of cigarette smoke alter global DNA methylation, and/or expression of DNA methyltransferases (Dnmts) and various methyl CpG-binding proteins. Primary cultures of 1-BA cells, exposed to 80μg/mL cigarette smoke extract (CSE) for 24h, exhibited a >13% decline in global DNA methylation and triggered proteasomal-mediated degradation of Dnmts (DNMT-1 and -3a), methyl CpG binding protein 2 (MeCP2) and methyl-CpG binding domain protein 3 (MBD-3). Pretreatment of 1-BA cells with the proteasomal inhibitor MG-132 completely reversed such degradation. Collectively, these data allow the suggestion of a potential epigenetic mechanism underlying maternal cigarette smoke exposure-induced orofacial clefting.
University of Louisville Birth Defects Center, Department of Molecular, Cellular and Craniofacial Biology, ULSD, University of Louisville, Louisville, KY 40202, United States.
Partha
P
Mukhopadhyay
University of Louisville Birth Defects Center, Department of Molecular, Cellular and Craniofacial Biology, ULSD, University of Louisville, Louisville, KY 40202, United States. Electronic address: dr.bob.greene@gmail.com.
Robert M
RM
Greene
University of Louisville Birth Defects Center, Department of Molecular, Cellular and Craniofacial Biology, ULSD, University of Louisville, Louisville, KY 40202, United States.
M Michele
MM
Pisano
D000818:Animals; D001934:Branchial Region / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D002478:Cells, Cultured; D002971:Cleft Lip / Q000201:enzymology / Q000235:genetics*; D002972:Cleft Palate / Q000201:enzymology / Q000235:genetics*; D018899:CpG Islands; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects; D000090205:DNA Methyltransferase 3A; D004268:DNA-Binding Proteins / Q000378:metabolism*; D044127:Epigenesis, Genetic / Q000187:drug effects; D005260:Female; D051783:Methyl-CpG-Binding Protein 2 / Q000378:metabolism*; D008813:Mice, Inbred ICR; D011247:Pregnancy; D061251:Primary Cell Culture; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors / Q000494:pharmacology; D059748:Proteolysis; D012307:Risk Factors; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects; D062789:Tobacco Products / Q000009:adverse effects*; D014157:Transcription Factors / Q000378:metabolism*
D004268:DNA-Binding Proteins; C492013:Mbd3 protein, mouse; C497393:Mecp2 protein, mouse; D051783:Methyl-CpG-Binding Protein 2; D061988:Proteasome Inhibitors; D012906:Smoke; D014157:Transcription Factors; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D046988:Proteasome Endopeptidase Complex
Branchial arch; Cigarette smoke; Cleft lip/palate; CpG-binding proteins; DNA methylation; DNA methyltransferases; Mouse; Proteasome