Gene expression profile of granulosa cells modulated by human FSH: role of oligosaccharide structure

LORETI NAZARETH; BALANIAN LILIANA; GROISMAN JOSÉ; CAMPO STELLA

Tours

Congreso; International Conference on Gonadotropins and receptors; 2014

FSH plays an essential regulatory role on ovarian folliculogenesis, particularly on granulosa cell function; its actions have important implications in fertility. The aim of this study was to analyze the response to different human FSH preparations in terms of gene expression at whole-genome scale in human granulosa-like tumor cell line, KGN, and to correlate transcriptional changes with specific biological functions. A microarray approach was used to explore gene expression pattern induced by recombinant human (rhFSH) and highly purified urinary human FSH (uhFSH). Preparative isoelectrofocusing was used to characterize uhFSH and to isolate glycosylation variants according to their sialylation degree. Two preparations, more (uhFSH-AC) and less sialylated (uhFSH-BA) were obtained from native uhFSH by combining pH4.40 fractions, respectively. Native rh and uhFSH were applied to a Concanavalin-A column to isolate FSH glycosylation variants according to their glycan complexity: unbound and weakly bound glycoforms (UB and WB) bearing complex type and firmly bound (FB) glycoforms bearing hybrid type oligosaccharides. The predominant proportion of rhFSH charge analogues was isolated within a 4.40-4.69 pH interval and those from uhFSH within 4.10-4.39. Three groups of glycoforms disclosed by lectin were detected in native rh and uhFSH preparations. A clear predominance of glycoforms bearing hybrid-type oligosaccharides was found in rhFSH (FB: 70% vs UB+WB: 30%) whereas glycoforms bearing complex carbohydrates were predominant in uhFSH (UB+WB: 83% vs FB: 17%). The expression of a large number of genes was differentially affected by the FSH preparations. Set enrichment analysis revealed that hormone sialylation degree differentially affected the expression of genes involved in essential biological processes and molecular functions of KGN cells. For example, genes related to inflammatory response and metabolic process were affected by rhFSH; genes associated with prostaglandin metabolic process and lipid catabolic process were affected by uhFSH. uhFSH-AC and uhFSH-BA affected the expression of genes associated with triglyceride homeostasis and interphase of mitotic cell cycle, respectively, between others. The results obtained in the present study clearly demonstrated differences in FSH sialylation and their oligosaccharides complexity between recombinant and urinary gonadotropin. A close relationship between the biological responses in terms of gene expression and the oligosaccharide structure present in the FSH molecule was also evidenced by differents transcriptomes.