The Vehicle Determines the Destination: The Significance of Seminal Plasma Factors for Male Fertility

Abstract

Of all human infertility cases, up to 50% show contributing factors leading to defects in the male reproductive physiology. Seminal plasma (SP) is the biological fluid derived from the male accessory sex gland which carries spermatozoa passing throughout the male and female reproductive tract during ejaculation. It contains a complicated set of heterogeneous molecular structures, including proteins, cell-free nucleic acid (DNA, microRNA and LncRNA), and small-molecule metabolites as well as inorganic chemicals (ions). For a long time, the substantial significance of seminal plasma factors’ functions has been underestimated, which is restricted to spermatozoa transport and protection. Notably, significant advancements have been made in dissecting seminal plasma components, revealing new insights into multiple aspects of sperm function, as well as fertilization and pregnancy outcomes in recent years. In this review, we summarize the state-of-art discoveries regarding SP compositions and their implications in male fertility, particularly describing the novel understanding of seminal plasma components and related modifications using “omics” approaches and mainly focusing on proteome and RNA-seq data in the latest decade. Meanwhile, we highlighted the proposed mechanism of the regulation of SP molecules on immunomodulation in the female reproductive tract. Moreover, we also discussed the proteins investigated as non-invasive diagnosis biomarkers for male infertility in the clinic.

Sperm Quality and Environment: A Retrospective, Cohort Study among 21,715 Semen Samples in a Southern Province of China

“…According to the records of the national meteorological station obtained from Guangzhou Climate Center, the annual average temperature, air pressure and air humidity in Guangzhou had no significant variations from 2018 to 2020. Therefore, the trend of decreasing or increasing among parameters may also be related to other factors, such as environmental pollution, mental stress, and extracellular environment of spermatogenesis [20]. But the timespan is only three years, more In our study, there was a strong positive correlation between sperm motility and PR (r = 0.934, p = 0.000).…”

The Activated AMPK/mTORC2 Signaling Pathway Associated with Oxidative Stress in Seminal Plasma Contributes to Idiopathic Asthenozoospermia

“…Metabolic disturbance in seminal plasma is a common factor leading to lower sperm motility [ 6 – 8 , 39 ]. ATR-FTIR is fast, easy-to-use, nondestructive, and noninvasive, and it does not need sample preparation nor any reagent, and it preserves the integrity of samples [ 24 , 25 ].…”

“…As an important component of semen, seminal plasma contains various biochemical molecules and nutrients, and it provides spermatozoa with a stable and safe microenvironment to perform physiological functions [ 6 – 8 ]. Notably, proteins extracted from seminal exosomes could prompt sperm capacitation through increased induction of tyrosine phosphorylation, therefore inducing the acrosome reaction [ 9 , 10 ].…”

Seminal Plasma: Relevant for Fertility?

“…Molecules showing association with (in)fertility are innumerable, but association between variables is not definitory of function in a general population. Markers for sperm dysfunction [ 218 ] and (in)fertility have been detected in spermatozoa [ 27 , 190 , 219 , 220 ] and in the SP [ 221 , 222 ] of many species, including humans [ 218 , 222 , 223 , 224 , 225 ] and livestock [ 70 , 226 ]. They vary from gene presence [ 227 ], markers of Sertoli cell function [ 228 ], proteins [ 36 , 229 , 230 , 231 ], anti-oxidative enzymes [ 223 , 232 , 233 ] and metabolites [ 234 , 235 , 236 ] to exosome-associated molecules [ 237 , 238 ] and microRNAs [ 181 , 239 , 240 , 241 ].…”