Fig 1: NPPC/cGMP/PDE3A/cAMP cascade is recovered by MSC-apoV infusion. (A) ELISA showing NPPC levels in MGCs. N = 3. (B) ELISA showing cGMP levels in CCs. N = 3. (C and D) ELISA showing PDE3A and cAMP levels in oocytes. N = 3. (E) ELISA showing NPPC levels in MGCs from WT mice after LiCl treatment. N = 3. (F) ELISA showing cGMP levels in CCs from WT mice after XAV939 treatment. N = 3. (G and H) Immunofluorescent co-staining of NPPC and active-β-catenin in the ovaries of Fasmut mice and MSC-apoV-treated Fasmut mice. Right panels are higher magnification views of the left boxed regions, highlighting TC and MGC regions (a, c, e), as well as oocyte and CC regions (b, d, f). White dashed lines are used to divide cells in different regions. Scale bars, 50 μm for lower magnification, 10 μm for higher magnification. (I and J) ELISA showing PDE3A and cAMP levels in oocytes of WT mice after XAV939 treatment. N = 3. (K) Graphical summary illustrating that WNT/β-catenin activation in MGCs triggers up-regulation of NPPC, leading to elevated levels of cGMP in CCs. Increased cGMP diffuses into oocytes to inhibit PDE3A activity and finally causes up-regulation of cAMP. On the other hand, down-regulation of WNT/β-catenin signaling in CCs and oocytes elevates the levels of cGMP and cAMP. Error bars are means ± SD. Data were analyzed two-tailed Student's unpaired t test for two-group comparison or using one-way analysis of variance (ANOVA) with Tukey's test. NS, not significant. *P < 0.05, **P < 0.01, ***P < 0.001.