RESUMEN
As a new mechanism of intercellular communication, the uptake of extracellular vesicles (EVs) by receptor cells has become a hot topic in the field. Previously, research on the uptake of EVs has focused on the mechanism of small EVs (sEVs, also known as exosomes). As sEVs represent a mixed heterogeneous population, the issue of whether there are different uptake mechanisms for different subsets of sEVs by recipient cells urgently need to be addressed. There are EVs in follicular fluid, which play an important role in the communication between follicular cells and the development of oocytes. Previously, we isolated two subtypes of sEVs in follicular fluid: low density-sEVs (LD-sEVs) and high density-sEVs (HD-sEVs). The current study aimed to explore the uptake characteristics of these two subtypes of sEVs by granulosa cells. First, PKH67 was used to label the two sEVs subtypes, and we observed their uptake by granulosa cells using confocal microscopy and flow cytometry. We then explored the specific mechanisms underlying uptake of these two sEV subtypes by granulosa cells using specific inhibitors and RNA interference. The results showed that granulosa cells took up both kinds of sEVs through a clathrin-independent pathway. In addition to requiring caveolin, cholesterol, and Na+/H+ exchange, the uptake of HD-sEVs also depended on the activity of tyrosine kinase and phosphoinositide 3-kinase. A better understanding of the mechanism of granulosa cell uptake of different subtypes of sEVs in follicular fluid is of considerable significance leading to more accurate use of EVs for targeted treatment of infertility and other related diseases.
RESUMEN
Non-obstructive azoospermia (NOA) is a disease characterized by spermatogenesis failure and comprises phenotypes such as hypospermatogenesis, mature arrest, and Sertoli cell-only syndrome. Studies have shown that FA cross-linked anemia (FA) pathway is closely related to the occurrence of NOA. There are FA gene mutations in male NOA patients, which cause significant damage to male germ cells. The FA pathway is activated in the presence of DNA interstrand cross-links; the key step in activating this pathway is the mono-ubiquitination of the FANCD2-FANCI complex, and the activation of the FA pathway can repair DNA damage such as DNA double-strand breaks. Therefore, we believe that the FA pathway affects germ cells during DNA damage repair, resulting in minimal or even disappearance of mature sperm in males. This review summarizes the regulatory mechanisms of FA-related genes in male azoospermia, with the aim of providing a theoretical reference for clinical research and exploration of related genes.