The Atypical Expression of Retinoic Acid Inducible GATA6 Protein in Placenta is a Convenient Biomarker for Newborn Health Assessment

Abstract

Background: Embryonic health assessment prior to delivery is not a priority in Africa due to the lack of efficient platforms for biomarker screening of defective heart or metabolic syndromes. Beside genetic mutations, some environmental, nutritional, or epigenetic events can induce abnormal protein expression impacting embryonic heart and gut developments. Among these proteins is the retinoic acid (vitamin A) inducible GATA6 which acts as transcription factor targeting the promoter of gene stimulated during placenta, embryonic heart and gut lineage specification. The objective of this study is to investigate GATA6 expression profile in placenta cells, to determine the impact of its abnormal expression on the newborn survival. Methods: Ethical approval of CER-ISBA) was obtained prior to placenta sample collection in the hospital obstetric service. Micro-fragments of placenta tissues (n=80) were collected after delivery and lysed for GATA6 analysis with immunoblot (western blot) method. Results: We observed two isoforms of GATA6 (long L and short S isoforms). All placenta lysates of living newborn expressed the type S isoform of GATA6 (n=76). In all 80 samples there is variable expression frequency for the type L isoform of GATA6. Normal expression of Type L isoform of GATA6 was observed in 63.8% of the samples; overexpression was observed in 7.5% of the samples; low expression was in 20% of them and totally lost in 8.7% of the samples. Retrospective analysis of 6 stillborn infant charts, linked 4 of them to deficient placental GATA6. Conclusion: Our preliminary data suggested that GATA6 could be used as biomarker for embryonic and newborn survival prognostic as well as for the postnatal screening of the risk to develop congenital heart diseases and metabolic syndromes during lifespan.