Regulation of mammalian sperm capacitation by endogenous molecules

Abstract

Capacitation in vitro in mammalian spermatozoa can be regulated by a number of first messengers, including fertilization promoting peptide, adenosine, calcitonin and angiotensin II, all of which are found in seminal plasma. The responses appear to involve several separate signal transduction pathways that have a common end point. These seminal-plasma derived first messengers can bind to specific receptors and directly or indirectly modulate the activity of membrane-associated adenylyl cyclase isoforms and production of the second messenger cAMP. Responses to all of these except angiotensin II involve initial acceleration of cAMP production and capacitation followed by inhibition of both cAMP production and spontaneous acrosome loss, resulting in maintenance of fertilizing potential. Appropriate G proteins and various phosphodiesterase isoforms also appear to be involved. The transition from stimulatory to inhibitory responses involves loss of decapacitation factors (DF) from receptors (DF-R) on the external surface; a DF-R present on both mouse and human spermatozoa has recently been identified as phosphatidylethanolamine-binding protein 1. The presence/absence of DF appears to cause changes in the plasma membrane that then alter the functionality of various membrane-associated proteins, including receptors. Since spermatozoa contact these first messengers at ejaculation, it is plausible that their actions observed in vitro also occur in vivo, allowing these molecules to play a pivotal role in enhancing the chances of successful fertilization.

Human Seminal Plasma Abrogates the Capture and Transmission of Human Immunodeficiency Virus Type 1 to CD4 + T Cells Mediated by DC-SIGN

“…These components are secreted from different sources: the testis, epididymis, and accessory glands (12,40). The average protein concentration of SP ranges from 35 to 55 g/liter, and proteomic analysis leads to the identification of more than 900 proteins (13,43,54).…”

Group X phospholipase A2 is released during sperm acrosome reaction and controls fertility outcome in mice

“…The endogenous factors responsible for spontaneous AR and the possible physiological reasons for this process have not been identified. Indeed, the molecular mechanisms of sperm capacitation are still poorly understood, even after 50 years of intensive research (5)(6)(7)(8)(9)(10). If capacitation clearly depends on cellular redox activity, ion fluxes, and protein phosphorylations, this process is also characterized by a strong dependence on the lipid membrane composition and lipid metabolism.…”

Semen Promotes the Differentiation of Tolerogenic Dendritic Cells

“…S emen contains a large and diverse array of components including carbohydrates, lipids, peptides, and proteins produced by different sources: the testis, the epididymis, and the accessory glands (1,2). The concentration of proteins in the seminal plasma ranges from 35 to 55 g/l, and proteomic analysis leads to the identification of .900 proteins (3,4).…”