Selective inhibition of murine palatal mesenchymal cell proliferation in vitro by secalonic acid D.
Secalonic acid D (SAD), a teratogenic mycotoxin, induces cleft palate (CP) in the offspring of exposed mice by inhibiting palatal shelf growth. Since reduced proliferation, increased apoptosis, and/or decreased extracellular matrix (ECM) synthesis of palatal mesenchymal cells (PMC) can all contribute to smaller shelf size, the hypothesis that teratogenically relevant concentrations (0 to 120 microg/ml) of SAD will have adverse effects on one or more of these cellular processes was tested, using primary murine PMC cultures. Exposure to SAD resulted in significant and dose-dependent decreases in mesenchymal cell number, uptake of (3)H-thymidine, and expression of proliferating cell nuclear antigen (PCNA). Trypan blue dye exclusion assay, however, revealed significant cell death only at higher doses, suggesting that the decrease in cell number at lower (more realistic) doses is likely a consequence of reduced cell proliferation and not cell death. Further, negative results in the DNA fragmentation analysis following SAD exposure suggested that cell death caused by higher levels of SAD was unrelated to apoptosis. Similarly, results of (3)H-glucosamine uptake assay indicated inhibitory effect of SAD on accumulation of hyaluronic acid (HA) or sulfated glycosaminoglycans (sGAG) only at the highest dose tested. Also, SAD affected neither extracellular nor cell-associated fibronectin expression at any dose tested. Taken together, these data suggest that the pathogenesis of CP by SAD is likely a result of a reduction in the size of the palatal shelf caused by SAD-induced inhibition of mesenchymal cell proliferation.
Hanumegowda
Umesh M
UM
Department of Veterinary Biomedical Sciences, University of Missouri, 1600 E. Rollins, Columbia, Missouri 65211, USA.
Judy
Barbara M
BM
Welshons
Wade V
WV
Reddy
Chada S
CS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000096:biosynthesis; D006025:Glycosaminoglycans / Q000096:biosynthesis; D006820:Hyaluronic Acid / Q000096:biosynthesis; D008297:Male; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009183:Mycotoxins / Q000008:administration & dosage / Q000633:toxicity*; D010159:Palate / Q000166:cytology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D014966:Xanthenes / Q000008:administration & dosage / Q000633:toxicity*; D044004:Xanthones
D005353:Fibronectins; D006025:Glycosaminoglycans; D009183:Mycotoxins; D018809:Proliferating Cell Nuclear Antigen; D014966:Xanthenes; D044004:Xanthones; D014316:Tritium; C009218:secalonic acid; D006820:Hyaluronic Acid; D013936:Thymidine