#285 : Amphiregulin Increases Pentraxin 3 Production via the EGFR-Mediated Erk1/2 Signaling in Human Granulosa Cells

Abstract

Background and Aims: Pentraxin 3 (PTX3) plays a key role in the assembly of the extracellular matrix, which is critical for cumulus expansion, ovulation, and in vivo fertilization. As a member of the epidermal growth factor family, amphiregulin (AREG) mediates luteinizing hormone (LH)-induced oocyte maturation and cumulus expansion in mammalian follicles. The aim of this study was to investigate whether AREG regulates the expression and production of PTX3 in human granulosa cells and to examine its underlying molecular determinants. Method: Immortalized human granulosa cells (SVOG cells) and primary human granulosa-lutein (hGL) cells obtained from women undergoing in vitro fertilization in an academic research center were used as the study models. The expression and accumulated levels of PTX3 were examined following cell incubation with AREG at different time points using the RT-qPCR and ELISA, respectively. Two kinase inhibitors (AG1478, and U0126) and small interfering RNAs targeting EGF receptor (EGFR) were used to verify the specificity of the effects and to investigate the molecular mechanisms. The results were analyzed by one-way analysis of variance. Results: The results showed that AREG upregulated the expression and production of PTX3 in primary and immortalized hGL cells. Additionally, using a dual inhibition approach (kinase inhibitors and siRNA-based expression knockdown), we demonstrated that this effect was mainly mediated by the EGFR receptor. Furthermore, we revealed that the Erk1/2 signaling is the downstream signaling pathway that mediates the increase in PTX expression and production in response to AREG treatment in hGL cells. Conclusion: AREG upregulated the expression of PTX3, leading to increased production of PTX3 in hGL cells. The AREG-induced cellular activities were most likely driven by the EGFR-mediated Erk1/2-dependent signaling pathway. Our findings shed light on the detailed molecular mechanisms by which AREG regulates the process of cumulus expansion and subsequent ovulation in humans.