Epididymosomes, prostasomes, and liposomes: their roles in mammalian male reproductive physiology

Abstract

Mammalian spermatozoa are unique cells in many ways, and the acquisition of their main function, i.e. fertilization capacity, is a multistep process starting in the male gonad and ending near the female egg for the few cells reaching this point. Owing to the unique character of this cell, the molecular pathways necessary to achieve its maturation also show some specific characteristics. One of the most striking specificities of the spermatozoon is that its DNA is highly compacted after the replacement of histones by protamines, making the classical processes of transcription and translation impossible. The sperm cells are thus totally dependent on their extracellular environment for their protection against oxidative stress, for example, or for the molecular changes occurring during the transit of the epididymis; the first organ in which post-testicular maturation takes place. The molecular mechanisms underlying sperm maturation are still largely unknown, but it has been shown in the past three decades that extracellular vesicles secreted by the male reproductive tract are involved in this process. This review will examine the roles played by two types of naturally occurring extracellular vesicles, epididymosomes and prostasomes, secreted by the epididymis and the prostate respectively. We will also describe how the use of artificial vesicles, liposomes, contributed to the study of male reproductive physiology.Reproduction (2013) 146 R21-R35

Germ Cell Origins of Posttraumatic Stress Disorder Risk: The Transgenerational Impact of Parental Stress Experience

“…Gestational or early life exposures likely reprogram primordial germ cells in the embryonic gonadal ridge or immature postnatal testis, and insults later in life may instead impact germ cells further along in spermatogenesis (64). Once sperm are fully mature, they are stored in the epididymis where epigenetic marks are thought to be largely impervious to change or to the environment (65), although limited evidence of intercellular communication between mature sperm and the epididymal epithelial cells suggests that small noncoding RNA populations in mature sperm may still be altered (66; 67). In the following sections, we explore evidence of transgenerational transmission through the three classes of epigenetic marks in sperm cells, examining their regulation through spermatogenesis and highlighting potential consequences on offspring reprogramming.…”

Interpreting histopathology in the epididymis

“…12 In the past 3 decades it has been shown that small membranous vesicles secreted by epididymal epithelial cells, i.e., epididymosomes, are involved in this sperm maturation. [13][14][15] Interestingly these epididymosomes have also been shown to transfer a specific sperm binding protein (ELSPBP1) to dead sperm during transit. 16 Recently, it was suggested that the cytoplasmic droplets, which are small cytoplasmic residues attached to the sperm after their release fromthe germinal epithelium and which migrates caudally along the sperm during epididymal transit, 13 represent a transient organelle that serves as an energy source essential for epididymal sperm maturation.…”

Characterisation of mouse epididymosomes reveals a complex profile of microRNAs and a potential mechanism for modification of the sperm epigenome

“…This environment is, in turn, created by the combined secretory and absorptive of the lining epithelium and characterised by considerable segment-segment variation4. A central component of epididymal soma-spermatozoa intercellular communication are epididymosomes, a heterogeneous population of small membrane bound vesicles that are released from the epididymal epithelium via an apocrine secretory mechanism5678. Similar to the exosome population documented in other somatic tissues and bodily fluids, epididymosomes are able to relay a complex macromolecular cargo to recipient cells91011.…”