“In previous publications we have shown that the low efficiency of spermatogenesis in infertile individuals is associated with altered gene expression patterns in the developing germ cells, which in turn contribute to a reduction in sperm production. In this context, it is reasonable to study the cellular miRNA expression behavior, as a likely mechanism of gene expression regulation, in spermatogenic disorders “, said Dr. Larriba. In this study it has been evaluated the levels of 623 mature miRNAs in histologically well defined testicular samples with impaired spermatogenesis at different stages of the germ line. The results suggest that the cellular content of miRNAs in sperm depends on the efficiency of spermatogenesis. The most notable differences are identified

the earlier the stage of germ-cell differentiation was affected by maturation failure. What is more,

spermatozoa that have fulfilled the differentiation process still retain the dysregulated miRNA pattern observed in the developing SpF germ-cells.

This molecular signature of altered miRNA has, most likely, functional implications for the male gamete, and may define the fertilizing capacity of the sperm. These results provide new insight into the molecular mechanisms that regulate and control male fertility, and provide elements for the development of new therapeutic tools.

Altered miRNA Signature of Developing Germ-cells in Infertile Patients Relates to the Severity of Spermatogenic Failure and Persists in Spermatozoa. Muñoz X, Mata A, Bassas L,

Larriba S.