The sperm journey in the excurrent duct: functions of microvesicles on sperm maturation and gene expression along the epididymis
Notice bibliographique
Résumé
Mammalian spermatozoa are differentiated, but unable to fertilize as they leave the testis. In order to acquire fertilizing ability and forward motility properties, the male gamete has to transit the epididymis. This process is collectively known as sperm maturation. The epididymis is a single convoluted tubule located between the vas efferens and the vas deferens; sperm epididymal transit takes 3 to 15 days depending on the species. Protein synthesis in the epididymis is highly active in response to androgen stimulation, and the underlying gene expression pattern shows great variability along this organ. For decades it has been recognized that interactions between the transiting spermatozoa and the intraluminal compartment of the epididymis govern complex modifications of sperm macromolecular composition that are necessary for sperm maturation. There is increasing interest in extracellular microvesicles that modulate cell-cell interactions in many physiological systems: such vesicles are found in the intraluminal compartment of the epididymis are called epididymosomes. We have shown that the epididymosome protein composition varies along the epididymis, and that a subset of these proteins is selectively transferred to the male gamete. These proteins are targeted to different sperm sub-compartments and are proposed to be involved in both the acquisition of fertilizing ability and forward motility properties. More recently, we used a bovine model to show that different subpopulations of epididymosomes are present in the fluid of a given epididymal segment. One of these subpopulations is proposed to be involved in the transfer of specific proteins by a membrane fusion process mediated by tetraspanin complexes, whereas another population of epididymosomes is involved in a mechanism that protects epididymal sperm against degenerating ones. Micro RNAs (miRNAs) are constituents of epididymosomes and microarray analyses have shown that the miRNA population characterizing epididymosomes varies with the site of collection along the epididymis. With the knowledge that miRNAs modulate transcriptional activity and that the pattern of gene expression shows great variation along the epididymis, we provide experimental evidence to support that miRNAs associated with epididymosomes modulate gene expression in the distal portion of their region of secretion along the male tract. Taken together, our work shows that microvesicles are one of the major players in the mechanisms underlying sperm maturation and modulation of gene expression along the epididymis. Clinical applications of these results will also be presented. The work described in this abstract was supported by grants from the Natural Sciences and Engineering Research Council of Canada.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».