The Proteome of Pig Spermatozoa Is Remodeled During Ejaculation

Abstract

The present study identified and quantified using iTRAQ-based LC-MS/MS, 1,723 and 1,602 proteins, respectively, in mature boar spermatozoa retrieved from cauda epididymis and three distinct fractions of the ejaculate. A total of 974 of the identified and 960 of the quantified proteins belonged to the Sus scrofa taxonomy. An ANOVA test revealed that 32 Sus scrofa proteins implicated in sperm function showed quantitative differences among sperm sources. The findings demonstrated that the proteome of boar spermatozoa is remodeled during ejaculation. Graphical Abstract Highlights• Proteome of mature boar spermatozoa from cauda epididymal and ejaculated sources were analyzed by iTRAQ-based LC-MS/MS.• 1,723 sperm proteins identified (974 of Sus scrofa taxonomy).• 1,602 sperm proteins quantified (960 of Sus scrofa taxonomy).• 32 Sus scrofa sperm proteins were differentially expressed among sperm sources.• The proteome of boar spermatozoa is remodelled during ejaculation. Proteins are essential for sperm function, including their fertilizing capacity. Pig spermatozoa, emitted in well-defined ejaculate fractions, vary in their functionality, which could be related to different sperm protein composition. This study aimed (i) to update the porcine sperm proteome and (ii) to identify proteins differentially expressed in mature spermatozoa from cauda epididymis and those delivered in separate ejaculate fractions. Ejaculates from nine mature and fertile boars were manually collected in three separate portions: the first 10 ml of the sperm-rich ejaculate fraction (SRF), the rest of the SRF and the post-SRF. The contents of cauda epididymides of the boars were collected post-mortem by retrograde duct perfusion, generating four different semen sources for each boar. Following centrifugation, the resulting pellets of each semen source were initially pooled and later split to generate two technical replicates per source. The resulting eight sperm samples (two per semen source) were subjected to iTRAQ-based 2D-LC-MS/MS for protein identification and quantification. A total of 1,723 proteins were identified (974 of Sus scrofa taxonomy) and 1,602 of them were also quantified (960 of Sus scrofa taxonomy).After an ANOVA test, 32 Sus scrofa proteins showed quantitative differences (p < 0.01) among semen sources, which was particularly relevant for sperm functionality in the post-SRF. The present study showed that the proteome of boar spermatozoa is remodeled during ejaculation involving proteins clearly implicated in sperm function. The findings provide valuable groundwork for further studies focused on identifying protein biomarkers of sperm fertility.

Changes in porcine cauda epididymal fluid proteome by disrupting the HPT axis: Unveiling potential mechanisms of male infertility

“…Its fluid is responsible for maintaining cell function and structural viability; thus, changes in this milieu could result in impaired sperm storage and decreased fertility. In the boar, several studies were published aiming to describe the epididymal proteome (Dacheux et al, 2005; Labas et al, 2015; Syntin et al, 1999, 1996) as well as the seminal plasma protein profile (Gonzalez‐Cadavid et al, 2014; Perez‐Patino et al, 2016, 2019; Strzezek et al, 2005) and molecular markers associated with semen quality (De Lazari et al, 2019) and freezability (Valencia, Gomez, Lopez, Mesa, & Henao, 2017; Vilagran et al, 2015). However, there is a gap in understanding how the epididymal milieu is impacted in pathological conditions, such as HPT‐axis disruption.…”

Boar seminal plasma: current insights on its potential role for assisted reproductive technologies in swine

“…Eleven proteins were differentially expressed in boars with high-and low-farrowing rates (8 overexpressed and 3 underexpressed in boars with high farrowing rates). Among the overexpressed proteins, 4 proteins (furin, UBA1, SPAM-1, and AKR1B1) showed a direct implication in male reproductive success, such as sperm maturation, capacitation, motility, and fertilizing ability (Pérez-Patiño et al, 2019). We speculate that a higher expression of these proteins would contribute to successful fertilization, as reflected by the higher farrowing rates obtained when these boars were used for AI.…”

“…However, it is generally accepted that conventional semen evaluation methods offer only a rough assessment of the real fertility potential of a boar (Dyck et al, 2011). In an attempt to overcome this drawback, special attention has been given to the study of the composition of seminal plasma (SP) as a potential source of biomarkers that could help to identify sub-fertile AI-boars that escape conventional semen screening yet providing sub-fertile semen (Pérez-Patiño et al, 2019). Sperm physiology and fertilizing ability are highly influenced by SP composition, which promotes sperm function and survival (Schjenken and Robertson, 2014).…”

Sperm Proteome after Interaction with Reproductive Fluids in Porcine: From the Ejaculation to the Fertilization Site

“…It is interesting to note that the OF group did not show these proteins, since all spermatozoa used for the experiment were in contact with SP during the ejaculation. In fact, these proteins belong to SP [ 118 , 119 ] that adhere to the sperm membrane, regulating motility and fertilizing ability [ 11 ]. In particular, PSP-I is involved in preventing an early acrosome reaction [ 120 ].…”

“…Through these interactions, spermatozoa are lost and/or selected, with only a few of them able to reach the fertilization site [ 4 , 5 , 6 , 7 , 8 , 9 ]. The spermatozoa surface undergoes changes both in the male and female genital tracts [ 10 , 11 ], by absorbing components released to the fluids they encounter along the way [ 12 , 13 ]. During the ejaculation, spermatozoa are immersed in the first reproductive fluid, the seminal plasma (SP), a complex biological fluid containing inorganic ions, citric acid, organic salts, and proteins, which is produced by the testes, epididymis, and, mainly, accessory reproductive organs (vas deferens, seminal vesicles, prostate, and bulbourethral glands) [ 14 ].…”