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Synthesis of recombinant human chorionic gonadotrophine in CHO and HEK-293 cells, purification and physicochemical characterization

Abstract

The human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by cells in the chorionic syncyotrophoblast tissue, a portion of the placenta, during the pregnancy. The average molecular mass of hCG is 37.18 kDa, and corresponds to two subunits, ± and ², of 92 and 145 amino acid residues, respectively, added of glycans, covalently linked. The ± subunit (common for hTSH, hFSH and hLH) has two N-glycosylation sites, while the ² subunit has two N-glycosylation and four O-glycosylation sites. The hCG promotes the embryo attachment to the endometrium and progesterone production by the corpus luteum. It is a therapeutic protein used in the treatments of cryptorchidism, male hypergonadism and mainly in assisted reproduction. The marketed therapeutic preparations come from hCG purified from urine of pregnant women or recombinant (rhCG), obtained in CHO cells (Chinese hamster ovary cells) cultures. This work proposes to perform the rhCG production by transient transfection in CHO and HEK-293 cells (human kidney embryo cells), to purify and characterize the hormone obtained by physicochemical and biological methods. There will be assessed three lineages: one CHO and HEK-293 commercial strains, and other CHO stablished in our lab. The glycan structures will be studied and compared to a reference hCG or commercial product. To this end, the implement of chromatographic and mass spectrometry methodologies is planned, in collaboration with other institutions in São Paulo. (AU)