Modifying The Rh Blood Group System Used Genetic Editing On Hematopoietic Stem Cells

Blood is an important part of human body.Blood type is determined by antigens on the surface of blood cells.Since the discovery of different types of blood,methods for identifying blood types have been continuously developed,from serological methods to molecular biological methods.Therefore,more and more blood type systems and antigens have been discovered,but the origin of blood type variation has not been clearly determined.There stay two main hypotheses.One is the blood-type diet hypothesis,which still lacks support.Another is the epidemic formation hypothesis.The Rh blood group system is the most complex system and plays an important role in clinical medicine.Among them,the RHD antigen expressed by RHD gene has the strongest immunogenicity,the presence of D antigen on red blood cells is used as the criterion to determine whether RHD is positive or negative.Rh-negative blood accounts for a very low proportion among the people in China,which makes it difficult to meet the demand for this type of blood.If the "universal blood" can be achieved,this problem can be greatly alleviated.So far,some researchers have tried using enzyme decomposition and other methods.Gene editing techniques were widely used because of the discovery of CRISPR system.In this study genetic editing technology is used to modify the RH blood group system on hematopoietic stem cells,and to achieve the RHD negative blood.Hematopoietic stem cells labeled CD34 and CD90 were successfully extracted from peripheral blood by flow cytometry and cultured in vitro.The CRISPR-cas9-mediated targeted gene editing recombinant plasmid was constructed with plasmid PX458,and transfected to 293 cells.The effective g RNA was found and analyzed.This study provides a preliminary attempt to modify the Rh blood group system on hematopoietic stem cells,and set up a practicable assay.