Oocyte-derived R-spondin2 promotes ovarian follicle development

FASEB J. 2013 Jun;27(6):2175-84. doi: 10.1096/fj.12-223412. Epub 2013 Feb 13.


R-spondin proteins are adult stem cell growth factors capable of stimulating gut development by activating LGR4, 5, and 6 receptors to promote Wnt signaling. Although multiple Wnt ligands and cognate Frizzled receptors are expressed in the ovary, their physiological roles are unclear. Based on bioinformatic and in situ hybridization analyses, we demonstrated the exclusive expression of R-spondin2 in oocytes of ovarian follicles. In cultured somatic cells from preantral follicles, R-spondin2 treatment (ED50: 3 ng/ml) synergized with Wnt3a to stimulate Wnt signaling. In cultured ovarian explants from prepubertal mice containing preantral follicles, treatment with R-spondin2, similar to follicle stimulating hormone, promoted the development of primary follicles to the secondary stage. In vivo administration of an R-spondin agonist stimulated the development of primary follicles to the antral stage in both immature mice and gonadotropin releasing hormone antagonist-treated adult mice. Subsequent treatment with gonadotropins allowed the generation of mature oocytes capable of undergoing early embryonic development and successful pregnancy. Furthermore, R-spondin agonist treatment of immune-deficient mice grafted with human cortical fragments stimulated the development of primary follicles to the secondary stage. Thus, oocyte-derived R-spondin2 is a paracrine factor essential for primary follicle development, and R-spondin agonists could provide a new treatment regimen for infertile women with low responses to the traditional gonadotropin therapy.

Keywords: FSH; Wnt pathway; embryos; follicle development; ovulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Female
  • Humans
  • Intercellular Signaling Peptides and Proteins / agonists
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred DBA
  • Mice, Inbred ICR
  • Mice, SCID
  • Oocytes / metabolism*
  • Ovarian Follicle / cytology
  • Ovarian Follicle / physiology*
  • Ovarian Follicle / transplantation
  • Paracrine Communication
  • Pregnancy
  • Thrombospondins / agonists
  • Thrombospondins / genetics
  • Thrombospondins / physiology*
  • Transplantation, Heterologous


  • Intercellular Signaling Peptides and Proteins
  • RSPO2 protein, mouse
  • Rspo2 protein, human
  • Thrombospondins