Susceptibility to DNA damage as a molecular mechanism for non-syndromic cleft lip and palate

Non-syndromic cleft lip/palate (NSCL/P) is a complex, frequent congenital malformation, determined by the interplay between genetic and environmental factors during embryonic development. Previous findings have appointed an aetiological overlap between NSCL/P and cancer, and alterations in similar biological pathways may underpin both conditions. Here, using a combination of transcriptomic profiling and functional approaches, we report that NSCL/P dental pulp stem cells exhibit dysregulation of a co-expressed gene network mainly associated with DNA double-strand break repair and cell cycle control (p = 2.88x10-2 – 5.02x10-9). This network included important genes for these cellular processes, such as BRCA1, RAD51, and MSH2, which are predicted to be regulated by transcription factor E2F1. Functional assays support these findings, revealing that NSCL/P cells accumulate DNA double-strand breaks upon exposure to H2O2. Furthermore, we show that E2f1, Brca1 and Rad51 involved in DNA repair are co-expressed in the developing embryonic orofacial primordia, and may act as a molecular hub playing a role in lip and palate morphogenesis. In conclusion, we show that cellular defences against DNA damage may take part in the pathogenesis of NSCL/P, in accordance with the hypothesis of aetiological overlap between this malformation and cancer. These results provide more information regarding the aetiology of NSCL/P and have the potential tocan potentially assist incontribute to the development of future preventive strategies. In order to analyze differences in gene expression between NSCL/P samples and controls we used 7 NSCL/P RNA samples extracted from dental pulp stem cells cultures and 6 control RNA samples also from dental pulp stem cells cultures, all in the same culture conditions. RNA samples were used in gene expression microarrays (Affymetrix HuGene 1.0 st chips).