Interpretive Summary: Wingless-type mouse mammary tumor virus integration site regulation of bovine theca cells

By Anne Zinn

A paper recently published in the Journal of Animal Science hypothesized that granulosa cells signal theca cells via secreted frizzled-related protein 4, Dickkopf-1, R-Spondin-1, and wingless-type mouse mammary tumor virus integration site (WNT1-11) secretion to regulate theca cells differentiation and proliferation. Specifically, the research team aimed to determine if the canonical WNT3A affects hormone-induced androstenedione production and cell proliferation and ascertain if other intrafollicular factors, such as insulin-like growth factor 1, bone morphogenetic protein 7, Indian hedgehog, and fibroblast growth factor 9, interacted with WNT3A on theca cells function. Additionally, the effects of R-Spondin-1, secreted frizzled-related protein 4, and Dickkopf-1 on theca cells function were evaluated. Better understanding the WNT system may lead to new strategies to improve reproductive efficiency in cattle.

In order to explore the hypothesis, in vitro experiments were conducted to study the effects of WNT3A, WNT5A, R-Spondin-1, Dickkopf-1, insulin-like growth factor 1, bone morphogenetic protein 7, Indian hedgehog, and fibroblast growth factor 9 on bovine theca cell proliferation and steroidogenesis.

The results of the present study, outlined in the full paper, support the idea that the WNT signaling pathway is involved in the regulation of theca cell proliferation and steroidogenesis, but further research is required to explain the specific mechanisms of action and dose responses of WNT, Dickkopf, and secreted frizzled-related protein 4 and their relationship with other molecules during follicular growth. A better understanding of the role of WNT and their molecular mechanisms will allow for a greater perspective on how these signals impact follicular maturation and subsequent conditions that could lead to ovarian cysts. Additionally, knowledge about the WNT system may be used to help the livestock industry improve reproductive efficiency by determining new treatments for estrous synchronization, superovulation, and cystic ovaries.

The full paper can be found on the Journal of Animal Science webpage.