Expression and Methylation Pattern of hsa-miR-34 Family in Sperm Samples of Infertile Men

Production of high-quality spermatozoa is necessary for male fertility. In this regard, post-mitotic stage in spermatogenesis is very important which posttranscriptional microRNAs (miRNAs) playing a key role at this stage. In this research, we evaluated the expression and methylation of hsa-miR-34 family in sperm samples of infertile men. We recruited 102 infertile men (asthenozoospermia, teratozoospermia, asthenoteratozoospermia, and oligoasthenoteratozoospermia) and 52 fertile men as control. The expression of hsa-miR-34a,b,c was determined by quantitative real-time PCR (qRT-PCR) technique. Methylation of hsa-miR-34b,c promoter was evaluated by methylation-specific PCR (MS-PCR) method. Our data indicated under-expression of three miRNAs (hsa-miR-34a,b,c) in the sperm samples of infertile men in compared to their fertile counterparts. The highest rate of expression reduction was observed in hsa-miR-34c-5p and in oligoasthenoteratospermic patients (P = 0.011, F = 4.01). The results revealed that the frequency of methylation of the promoter region of hsa-miR-34b,c in infertile men was higher than that of fertile men (82.4% versus 23.3%), and the highest frequency of methylation was observed in patients with asthenoteratospermia (92.9%) and oligoasthenoteratospermia (93.8%). In conclusion, our results indicated lower expression of hsa-miR-34a,b,c and hypermethylation of hsa-miR-34b,c promoter in sperm samples of infertile men. Aberrant under-expression of these miRNAs could be duo to the hypermethylation of the promoter region and indicative of a defect in spermatogenesis.