Avicenna J Med Biotech arij002 Avicenna Journal of Medical Biotechnology 2008-2835 2008-4625 Avicenna Research Institute ajmb252 Exogenous Secreted Frizzled-Related Protein-4 Modulates Steroidogenesis of Rat ‎Granulosa Cells Through Wnt/Bcatenin and PI3K/AKT Signaling Pathways‎ HosseinGhamartajDepartment of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, IranKhanmohammadiManijehDepartment of Medical Physics, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, IranSahranavard FardParissaDepartment of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, IranHeidarianYasamanDepartment of Physics, Nano-center, Maleke-ashtar University of Technology, Shahin-shahr, Isfahan, IranKazemnejadSomaiehNanobiotechnology Research Center, Avicenna Research Institute , Tehran, IranImmunology Research Center, Faculty of Medicine, Iran University of Medical Sciences , Tehran, IranAkhondiMohammad MehdiDepartment of Immunology, Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR , Tehran, Iran 8 4 159 168 10 4 2016 11 5 2016

<p>Background: It has been reported that secreted frizzled-related protein-4 known as an antagonist of Wnt signaling pathway plays a role in luteinization process of rodent granulosa cells. The purpose of this study was twofold: 1) to determine whether recombinant human secreted frizzled-related protein-4 (rhSFRP-4) could directly induce terminal differentiation of rat Granulosa Cells (GCs) and 2) to understand how the modulation of &beta;-catenin and Protein Kinase B (PKB)/AKT activity by exogenous SFRP-4 could be involved in steroidogenesis.<br /> Methods: GCs were firstly stimulated with Follicle-Stimulating Hormone (FSH) named as FSH-primed cells then were treated with luteinizing hormone (LH). Then estradiol (E<sub>2</sub>) and progesterone (P<sub>4</sub>) production levels were assessed in the absence or presence of rhSFRP-4 treatment. The expression levels of activated &beta;-catenin, pAKTser<sup>473</sup>, pGSK3&beta;ser<sup>9</sup> were assessed by western blot or immuno-fluoresence.<br /> Results: In the presence of rhSFRP-4, there was 38% decreased E<sub>2</sub> levels compared to untreated FSH-primed cells (p&lt;0.05), and P<sub>4</sub> production subsequently decreased. However, in GCs pre-treated with rhSFRP-4 prior to addition of FSH, P<sub>4</sub> levels increased 2-fold compared with untreated cells (p&lt;0.05). Unexpectedly, treatment with rhSFRP-4 prior to LH stimulation inhibited LH-induced P<sub>4</sub> secretion. Treatment with low (0.5 <em>ng/ml</em>) but not high (50 <em>ng/ml</em>) concentrations of rhSFRP-4 led to significantly increased levels of pGSK3&beta;ser<sup>9</sup> (1.6-fold) and nuclear active &beta;-catenin (2.8-fold) in GCs compared with untreated cells. Interestingly, pre-treating GCs with rhsFPR4 prior to LH stimulation resulted in a 38% decrease in pAKTser<sup>473</sup> levels compared with those in LH-treated cells (p&lt;0.05).<br /> Conclusion: Taken together, our results showed that rhSFRP-4 could directly induce terminal differentiation in GCs via the modulation of &beta;-catenin and PKB/AKT pathways and that it does so in a dose-dependent manner.</p>