A novel, more efficient approach to generate bioactive inhibins

Kelly L. Walton, Emily K. Kelly, Katharine E. Johnson, David M. Robertson, Peter G. Stanton, Craig A. Harrison

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

Abstract

Gonadal-derived inhibins are essential factors in mammalian reproduction, negatively regulating pituitary production of FSH. Interestingly, declines in inhibin levels across the menopause transition correlate with not only anincrease in FSH but also a rapid decrease in bonemass. Therefore, inhibins have been touted as potential therapeutics for osteoporosis in postmenopausal women. However, as heterodimeric proteins of α- and β- (βA or βB)-subunits, inhibins are difficult to produce recombinantly, are poorly processed to their mature bioactive forms, and their expression is always accompanied by production of activins (β-subunit homodimers), the proteins they antagonize. In this study,wedeveloped themethodologyto circumventmostof these issues. Initially, the cleavage sites between the pro- and mature domains of the α- and βA-subunits were modified to ensure complete processing. These modifications led to a marked increase (9-fold) in the levels of bioactive inhibin A and a striking decrease (12.5-fold) in mature activin A production. Next, a single point mutation (M418A) was incorporated into the βA-subunit, which reduced residual activin activity approximately 100-fold and, in so doing, increased inhibin bioactivity 8-fold. Finally, we showed that inhibin A noncovalently associated with its prodomain was more potent (∼20-fold) than mature inhibin A in specific in vitro bioassays, indicating an important role of the prodomain in inhibin bioactivity. In conclusion, the production of potent inhibin analogs in the virtual absence of activin activity will greatly facilitate the investigation of the therapeutic potential of these gonadal hormones on bone and other tissues.

Original languageEnglish
Pages (from-to)2799-2809
Number of pages11
JournalEndocrinology
Volume157
Issue number7
DOIs
Publication statusPublished - 1 Jul 2016
Externally publishedYes

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