Purinergic receptor detection in human embryonic epidermis

Abstract

The integumentary system covers the surface of the embryo (skin) and its specialized skin structures including hair, nails, sweat glands, mammary glands and teeth. During fetal skin development, the epidermis changes from a single layer of ectodermal cells at 7–8 days of gestation into a more apparent stratified, keratinized epithelium at 22–24 weeks. Skin development is driven by the complex inter-play between intrinsic and extrinsic pathways. There has been significant interest in determining the molecular cues that regulate the proliferation of human epidermal cells.P2Y receptors are membrane bound G protein coupled receptors. Purinergic signalling mediated by nucleotides such as Adenosine Triphosphate (ATP) and Adenosine Diphosphate (ADP) has also been shown to play a significant role in embryogenesis. Aim:The aim of the study is to identify the presence of purinergic receptors P2Y1,P2Y2,and P2Y4 during human embryonic epidermis development. The expression of purinergic receptors is examined in various anatomical sites and embryonic stages. Human embryonic samples were obtained from fully informed,consenting patients undergoing spontaneous terminations of pregnancy from emergency department at Al-Hilla maternity. Anatomical Sites included abdomen,forehead,back and feet sole. A total of 15 embryos aged between 2-3 months were used for this study. Fresh tissues were sectioned using a freezing cryostat. Tissues were sectioned at 5µm in -24°C and collected on microscopic slides. Slides were allowed to air dry for 30 min prior to immunohistochemical processing. Our study shows strong positivestaining for purinergic receptors P2Y1,P2Y2,and P2Y4 in all selected anatomical sites. Immunohistochemical staining increases with gestational development in all selected anatomical sites. A strong expression of purinergic receptors is seen in anatomical areas which possess high rate of development and strong differentiation rate.purinergic receptors as stem cell markers are actively seen in human epidermis histogeneis and development. Their role is important is epidermal layer proliferation and differentiation.