Phosphatidylserine induced up-regulation of Cluster Differentiation 36 and 47 on red cell membrane

Scientific Affairs, Sudanese Council for Medical Specialties, Khartoum, Sudan. Corresponding email: hishamwagg30@hotmail.com Abstract: Aim: The purpose of this research was to study the expression of CD36 and CD47 on red cell membrane following perturbation of red cell membrane with phosphtidylserine (PS). Materials and Methods: Blood was drawn from 100 healthy adults; Incubation of RBCs with different serial concentrations of PS was carried out at 37°C for 72 hrs. All tubes were washed followed by addition of CD36-FITC and CD47-FITC antibodies, Cells were analyzed for the expression of CD markers using the FACS analyzer. Data were analyzed by using Statistical Package for Social Science (SPSS) version 21 and Microsoft Excel 2013. Results: were obtained by using student T . test. Result: CD36 expression is directly proportional to PS serial dilutions; however the expression of CD47 is raised in the last three higher concentrations. Conclusion: We conclude that CD47 has been shown to inhibit phagocytosis of erythrocytes by macrophages of the reticuloendothelial system, whilst CD36 responsible of recognition of red cell by macrophage and accelerating engulfing process PS induced up regulation of CD36 and CD47 which may encourage their conversed action and participate in keeping red cell as much as normal in diseases associated with high concentration of PS. [Waggiallah H, Baghdadi H, Hemeg H, Ozbak H, Mohamed B, Ahmed A. Phosphatidylserine induced up-regulation of Cluster Differentiation 36 and 47 on red cell membrane. Life Sci J 2014;11(6):105-109]. (ISSN:1097-8135). http://www.lifesciencesite. com. 15 Keywords: Phosphatidylserine, CD36, CD47, Red cell membrane. 1. Introduction The human RBC (RBC) membrane consists of lipids (41%), proteins (52%), and carbohydrates (7%). [1, 2] In average, there are about 5.2 mg membrane lipids per ml of packed RBCs or approximately 5.2 × 10-13 g/cell. Membrane lipids can be classified into three classes: neutral lipids (25.2%), phospholipids (62.7%) and glycosphingolipids (about 12%). Neutral lipids of human RBCs represent cholesterol almost exclusively [3, 4]. The ratio of cholesterol to phospholipid is about 0.8. Phospholipids consist of sphingomyelin (SM, 26%), and glycerophospholipids. [5] The lipid composition of RBC membrane is rather stable and only alters with diet to a limited extent [6, 7]. This is due to the lack of de novo synthesis of phospholipids in the mature RBC. Limited alterations of the fatty acid composition by diet result from the exchange of phospholipids, primarily PC, between plasma lipoproteins and the cell membrane, as well as the exchange of fatty acids [8, 9] CD36 is a multi-functional molecule. It has independent binding sites for different classes of ligands Such as modified phospholipids, thrombospondins, and free fatty acids. This enables CD36 responsible for several different cellular processes depending on the nature of the ligand and the type and location of the cell on which it is expressed. [10] CD36 also functions as an adhesion molecule. [11] CD47 is a 47–52 kDa transmembrane glycoprotein with a ubiquitous expression profile in human tissues that includes erythrocytes [12]. On mature erythrocytes, which lack integrins, CD47 appears to mediate cell-cell interactions with SIRP- of splenic macrophages. This association is thought to inhibit a phosphorylation cascade that blocks phagocytosis and prevents erythrocyte clearance from the circulation. [13] The purpose of this research was to study the expression of CD 36 andCD47 on red cell membrane following perturbation of red cell membrane with phosphtidylserine. 2. Material and Methods Blood was drawn by venipuncture into evacuated tubes containing EDTA anticoagulant. Nor mal samples were drawn from 100 healthy apparently adult male volunteers, his lipid profile within normal range. Samples were classified into three categories: Ten participants as control group without adding any reagent and other two groups 45 participants for each were tested for CD36 and CD47. Stock concentration (1000 mg/ml) of L-a-lysophosphatidylserine (commercial name of phosphtidylserine PS) was dissolved in 4 ml RPMI medium under sterile conditions followed by