Increased biological activity due to basic isoforms in recombinant human follicle-stimulating hormone produced in a...

Area of Science:

• Endocrinology
• Glycobiology
• Protein Chemistry

Background:

• Follicle-stimulating hormone (FSH) is a glycoprotein hormone crucial for reproductive function.
• FSH exists as a heterogeneous group of isoforms due to variable glycosylation, impacting biological activity.
• Current recombinant FSH preparations may not fully replicate the circulating isoform spectrum.

Purpose of the Study:

• To produce recombinant human FSH (hFSH) in a novel cell line (HEK-293) to broaden the isoform profile.
• To evaluate the biological activity and isoform distribution of the newly produced recombinant hFSH (hFSH-293).
• To compare the biological potency and isoform profile of hFSH-293 with pituitary FSH standards.

Main Methods:

• Transfection of human embryonal kidney (293) cells with human alpha and FSH beta genes.
• Production of recombinant hFSH (hFSH-293).
• Immunological characterization and biological activity assessment using a rat granulosa cell bioassay.
• Isoform separation by chromatofocusing and potency determination.

Main Results:

• hFSH-293 was immunologically similar to pituitary FSH but exhibited 3- to 6-fold higher biological potency.
• Chromatofocusing revealed a higher proportion of basic FSH isoforms in hFSH-293 compared to pituitary FSH.
• Specific basic isoforms of hFSH-293 demonstrated enhanced in vitro biological potency.

Conclusions:

• Production of recombinant hFSH in HEK-293 cells yields a distinct isoform profile with enhanced biological activity.
• The increased potency of hFSH-293 is attributed to a greater abundance of biologically active basic isoforms.
• This isoform profile resembles that of endogenous FSH during specific physiological states like ovulation and GnRH stimulation.