Alteration of DNA Damage Response Causes Cleft Palate

Let-7c-5p associate with inhibition of phenobarbital-induced cell proliferation in human palate cells

Cleft palate (CP) is one of the most common congenital diseases, and is accompanied by a complicated etiology. Medical exposure in women is among one of the reasons leading to CP. Recently, it has been reported that microRNA (miRNA) plays a crucial role in palate formation and the disruption of miRNA that influence the development of CP. Although association with pharmaceuticals and miRNAs were suggested, it has remained largely unknow. The aim of the current investigation is to elucidate upon the miRNA associated with the inhibition of phenobarbital (PB)-induced cell proliferation in human embryonic palatal mesenchymal (HEPM) cells. We showed that PB inhibited HEPM cell viability in a dose-dependent manner. We demonstrated that PB treatment suppressed cyclin-D1 expression in HEPM cells. Furthermore, PB upregulated let-7c-5p expression and downregulated the expression of two downstream genes (BACH1 and PAX3). Finally, we demonstrated that the let-7c-5p inhibitor alleviated PB-induced inhibition of cell proliferation and altered BACH1 and PAX3 expression levels. These results suggest that PB suppresses cell viability by modulating let-7c-5p expression.

Involvement of microRNA-4680-3p against phenytoin-induced cell proliferation inhibition in human palate cells

Cleft palate (CP) is one of the most common birth defects and is caused by a combination of genetic and/or environmental factors. Environmental factors such as pharmaceutical exposure in pregnant women are known to induce CP. Recently, microRNA (miRNA) was found to be affected by environmental factors. The aim of the present study was to investigate the involvement of miRNA against phenytoin (PHE)-induced inhibition of proliferation in human embryonic palatal mesenchymal (HEPM) cells. We demonstrated that PHE inhibited HEPM cell proliferation in a dose-dependent manner. We found that treatment with PHE downregulated cyclin-D1 and cyclin-E expressions in HEPM cells. Furthermore, PHE increased miR-4680-3p expression and decreased two downstream genes (ERBB2 and JADE1). Importantly, an miR-4680-3p-specific inhibitor restored HEPM cell proliferation and altered expression of ERBB2 and JADE1 in cells treated with PHE. These results suggest that PHE suppresses cell proliferation via modulation of miR-4680-3p expression.

Diabetes, Oxidative Stress, and DNA Damage Modulate Cranial Neural Crest Cell Development and the Phenotype Variability of Craniofacial Disorders

Craniofacial malformations are among the most common birth defects in humans and they often have significant detrimental functional, aesthetic, and social consequences. To date, more than 700 distinct craniofacial disorders have been described. However, the genetic, environmental, and developmental origins of most of these conditions remain to be determined. This gap in our knowledge is hampered in part by the tremendous phenotypic diversity evident in craniofacial syndromes but is also due to our limited understanding of the signals and mechanisms governing normal craniofacial development and variation. The principles of Mendelian inheritance have uncovered the etiology of relatively few complex craniofacial traits and consequently, the variability of craniofacial syndromes and phenotypes both within families and between families is often attributed to variable gene expression and incomplete penetrance. However, it is becoming increasingly apparent that phenotypic variation is often the result of combinatorial genetic and non-genetic factors. Major non-genetic factors include environmental effectors such as pregestational maternal diabetes, which is well-known to increase the risk of craniofacial birth defects. The hyperglycemia characteristic of diabetes causes oxidative stress which in turn can result in genotoxic stress, DNA damage, metabolic alterations, and subsequently perturbed embryogenesis. In this review we explore the importance of gene-environment associations involving diabetes, oxidative stress, and DNA damage during cranial neural crest cell development, which may underpin the phenotypic variability observed in specific craniofacial syndromes.