ESPE Abstracts

Introduction: Growth hormone (GH) is essential for stimulating growth and cell proliferation through its effects on metabolism, cartilage and bone growth. We have conducted initial studies to find new biomarkers for GH deficiency and early treatment response, focusing on miRNAs expressed in both sexes. We aimed at investigating sex-specific differences in circulating miRNAs at baseline and after 3 months on GH treatment in a cohort of prepubertal children with isolated idiopathic GH deficiency (IIGHD).

Methods: We re-analyzed our previously published miRNA global profiling (GSE193450) dataset to identify differences between females (F) (N:5, CA:7.44±2.46) and males (M) (N:5; CA:10.16 ± 2.14) before and after 3 months of GH therapy. Significant miRNAs were selected based on p-value (P < 0.05) or fold change (log₂2−DDCt) > +1.5 or FC (log₂2−DDCt) < −1.5. KEGG enrichment was performed with deregulated miRNAs to establish biological pathways impacted.

Results: At baseline, we identified 13 differentially expressed miRNAs between F and M. The 4 miRNAs upregulated in females (hsa-miR-380-3p, hsa-miR-486-5p, hsa-miR-325, hsa-miR-185-5p) and the 9 upregulated miRNA in males (hsa-miR-30b-5p, hsa-miR-30c-5p, hsa-miR-132-3p, hsa-miR-139-5p, hsa-miR-142-5p, hsa-miR-195-5p, hsa-miR-197-3p, hsa-miR-200c-3p, hsa-miR-340-5p) had a similar effect on the cell cycle pathway and Wnt signaling, involved in osteoblast differentiation and bone metabolism. However, miRNAs in F had a greater impact on p53 signaling, crucial for osteogenic differentiation, whereas miRNAs in M affected mostly TGF-β signaling, involved in bone formation. After 3 months on GH therapy, two of the miRNA above (hsa-miR-325 and hsa-miR-30c-5p) were still differentially expressed in M and F, suggesting that hormone replacement didn't restore sex-specific differences. Other 8 miRNAs were differentially expressed in F and M after 3 months of therapy and were involved in cell cycle, p53, mTOR (mediator of bone anabolism) and insulin signaling. Nevertheless, the level of significance of these pathways was different between the two groups. With an analysis comparing baseline and 3 months of therapy in M and F separately, we identified that cell cycle was similarly affected by deregulated miRNAs in both sexes. However, p53 and insulin signaling, and endocytosis were more impacted in F whereas pathways in M were enriched for Wnt signaling and RNA transport.

Conclusion: This study evidenced differences in miRNAs expression profiles in GH deficient males and females, both at baseline and after 3 months on GH therapy. Our aim is to emphasize the importance of considering gender-specific factors in therapeutic strategies, which currently has not been done for GH deficiency.