The expression of the new epididymal luminal protein of PDZ domain containing 1 is decreased in asthenozoospermia

Sperm immotility is associated with epididymis metabolism disorder in mice under obstructive azoospermia

Obstructive azoospermia (OA) accounts for approximately 40% of males who suffer from azoospermia of male infertility. Currently, available treatment for OA consists of reproductive tract surgical reconstruction and sperm retrieval from the testis. However, both treatments result in low fertility compared to normal pregnancy, and the main reason remains largely unknown. Previous studies have shown that the quality of sperm retrieved from OA patients is poor compared with normal adult males but without an in-depth study. Herein, we generated a mouse OA model with vasectomy to evaluate sperm quality systematically. Our results showed that the testis had normal spermatogenesis but increased apoptotic activity in both OA patients and mice. More importantly, epididymal morphology was abnormal, with swollen epididymal tubules and vacuole-like principal cells. Especially, sperm retrieved from the epididymis of OA mice showed poor motility and low fertilization ability in vitro. Using mass spectrometry in epididymal fluid, we found differences in the expression of key proteins for sperm maturation, such as Angiotensinogen (AGT), rhophilin-associated tail protein 1 (ROPN1), NPC intracellular cholesterol transporter 2 (NPC2), and prominin 1 (PROM1). Furthermore, our results demonstrated that AGT, secreted by epididymal principal cells, could regulate sperm motility by managing PKCα expression to modify sperm phosphorylation. In conclusion, our data evaluate sperm quality systematically in OA mice and contribute to the understanding between the sperm and epididymis, which may provide novel insight into treating male infertility.

Revealing stage-specific expression patterns of long noncoding RNAs along mouse spermatogenesis

The discovery of a large number of long noncoding RNAs (lncRNAs), and the finding that they may play key roles in different biological processes, have started to provide a new perspective in the understanding of gene regulation. It has been shown that the testes express the highest amount of lncRNAs among different vertebrate tissues. However, although some studies have addressed the characterization of lncRNAs along spermatogenesis, an exhaustive analysis of the differential expression of lncRNAs at its different stages is still lacking. Here, we present the results for lncRNA transcriptome profiling along mouse spermatogenesis, employing highly pure flow sorted spermatogenic stage-specific cell populations, strand-specific RNAseq, and a combination of up-to-date bioinformatic pipelines for analysis. We found that the vast majority of testicular lncRNA genes are expressed at post-meiotic stages (i.e. spermiogenesis), which are characterized by extensive post-transcriptional regulation. LncRNAs at different spermatogenic stages shared common traits in terms of transcript length, exon number, and biotypes. Most lncRNAs were lincRNAs, followed by a high representation of antisense (AS) lncRNAs. Co-expression analyses showed a high correlation along the different spermatogenic stage transitions between the expression patterns of AS lncRNAs and their overlapping protein-coding genes, raising possible clues about lncRNA-related regulatory mechanisms. Interestingly, we observed the co-localization of an AS lncRNA and its host sense mRNA in the chromatoid body, a round spermatids-specific organelle that has been proposed as a reservoir of RNA-related regulatory machinery. An additional, intriguing observation is the almost complete lack of detectable expression for Y-linked testicular lncRNAs, despite that a high number of lncRNA genes are annotated for this chromosome.