[Expression of human long-acting FSH in CHO cell and its bioactivity in vivo]

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein hormone that is essential for the development of ovarian follicles and testicular seminiferous tubules. The relatively short half-life of FSH in vivo requires daily injections for more than 10 days that is inconvenient and possibly contribute to the stress perceived by the patients. The goal of the present study was to increase FSH glycosylation, in order to develop a long-acting recombinant FSH. The cDNA of native alpha and beta subunit of human FSH was linked by a sequence with two N-linked glycosylation sites, and the resulted DNA was inserted into pcDNA3.1 vector to generate a recombinant vector of pcDNA3.1-FSH. The pcDNA3.1-FSH was linearized and transfected into CHO-K1, positive transformants were selected by G418 and confirmed by PCR and Western blotting. A single chain recombinant FSH was expressed, with molecular weight of about 49 kDa. The recombinant FSH expression level in CHO-K1 cell strain in serum-free culture was 3 mg/L. Single injection of this recombinant FSH could induce folliculogenesis and ovulation in rats, the efficacy was similar with the commercially available FSH preparation (Folltropin-V) administrated 8 times consecutively. The results suggested a long-acting FSH was produced successfully.