Establishment Of The Lipid Droplets Deficient Mouse Embryo Stem Cell Lines

Embryonic stem cells are pluripotent stem cell lines established from the inner cell mass of early blastocyst stage embryos.Under appropriate conditions,embryonic stem cells can maintain self-renewal activity and possess the ability to infinite proliferation.With these characteristics,they can be widely applied to many areas:the mechanism of early embryogenesis,the mechanism of disease,drug screening and regenerative medicine.So far,studies have found that the maintenance of pluripotency is regulated by multiple networks,including coordination among signaling pathways,organelles,pluripotent genes and metabolic pathways,etc.Some studies have shown that both carbohydrate and amino acid metabolism play important roles in the maintenance of self-renew,suggesting that metabolisms is very important for embryonic stem cells.However,the relation between lipid metabolism and pluripotency needs further investigation.Our studies focused on lipid metabolism and lipid dropolets in embryonic stem cells and the related mechanism.First,we found that lipid droplets located in the early stage of embryogenesis and pluripotent stem cells.Embryonic stem cells derived differentiation accompanies with the disappearance of lipid droplets.The expression of lipid droplets related genes also decreased during this period.On the other hand,lipid droplets in the ground state of embryonic stem cells are associated with the cultural time and the growth state of the cell clones.We performed Talen and CRISPR-Cas9 methods to knockout three lipid droplet related genes,Tip47,Adrp,and Dgat1.Tip47 and Adrp belongs to lipid droplets structural genes,and Dgatl is a key enzyme in the synthesis of lipid droplets.In both Tip47 single knockout and Dgatl single knockout mouse embryonic stem cells,the pluripotency and lipid droplets had no significant changes.In Tip 47,Adrp double knockout embryonic stem cells,the lipid droplets of this cell lines disappeared.And the cells were more sensitive to the stimulation of differentiation.In short,we identified the role of lipid droplets and their related genes in maintaining embryonic stem cells pluripotency,and provided a new direction for studying the mechanisms between lipid metabolism and pluripotency of embryonic stem cells.