Serine protease PRSS55 is crucial for male mouse fertility via affecting sperm migration and sperm–egg binding

Abstract

Testis-specific PRSS55 is a highly conserved chymotrypsin-like serine protease among mammalian species. So far, the physiological function of PRSS55 remains unknown. Here, we show that PRSS55 is a GPI-anchored membrane protein, specifically expressed in adult mouse testis and mainly observed in the luminal side of seminiferous tubules and sperm acrosome. Mice deficient for Prss55 develop male infertile with normal reproduction-related parameters observed. Interestingly, in vivo fertilization rate of Prss55−/− males is dramatically decreased, possibly due to incapable migration of Prss55−/− sperm from uterus into oviduct. However, in vitro fertilization rate has no difference between two genotypes although Prss55−/− sperm presents defective recognition/binding to zona-intact or zona-free oocytes. Further study reveals that mature ADAM3 is almost undetectable in Prss55−/− sperm, while precursor ADAM3 remains unchanged in the testis. However, it is shown that ADAM3 has no interaction with PRSS55 by immunoprecipitation with anti-PRSS55 antibody. The expression levels of several proteins known to be related to the observed phenotypes remain comparable between wt and Prss55−/− mice. Moreover, we found that Prss55 deficiency has no effect on PRSS37 or vice versa albeit two mutant males share almost the same phenotypes. Microarray analysis reveals a total of 72 differentially expressed genes in Prss55−/− testis, most of which are associated with cellular membrane and organelle organization, protein transport and complex assembly, and response to stimulus and signaling. In conclusion, we have demonstrated that PRSS55 plays vital roles in regulating male fertility of mice, including in vivo sperm migration and in vitro sperm–egg interaction, possibly by affecting the maturation of ADAM3 in sperm and the expression of multiple genes in testis.Electronic supplementary materialThe online version of this article (10.1007/s00018-018-2878-9) contains supplementary material, which is available to authorized users.

An update of the regulatory factors of sperm migration from the uterus into the oviduct by genetically manipulated mice

“…Recently, we identified two new serine proteases, PRSS37 and PRSS55, which are related to the fertilization process. Specifically, Prss37 and Prss55 ‐null mice almost exhibited similar phenotypes, including decreased the fertilization rates accompanied by a defect in sperm migration from the uterus into the oviduct in vivo, and the displayed sperm were incapable of sperm–egg recognition/binding in vitro (Figure ; Shang et al, ; Shen et al, ). The main difference between PRSS37 and PRSS55 is that PRSS37 disappears during the late steps of spermatogenesis in the testis, whereas PRSS55 remains present in the mature sperm of the epididymis (Shang et al, ).…”

“…ADAM3 requires assistance from the genes discussed above for proper delivery onto the surface of sperm, and in all of the reported gene‐disrupted mice described previously (except for t‐ACE, in which the microlocalization of ADAM3 on sperm is impaired, and PGAP1 and LY6K, in which the amounts of ADAM3 on sperm are normal), ADAM3 is always missing from the sperm plasma membrane (Fujihara, Miyata, et al, 2018; Ikawa et al, ; Shang et al, ; Tokuhiro et al, ). Regrettably, there is no concrete evidence showing that ADAM3 is the element ultimately attributed to sperm migration through the UTJ.…”

“…It is reasonable to consider that the defects in Prss37 ‐ and Prss55 ‐null male sperm migration from the uterus into the oviduct are attributed to the disappearance of mature ADAM3 rather than the deficiency of Prss37 and Prss55 . Regrettably, no direct interaction of PRSS37 and PRSS55 with precursor or mature ADAM3 was detected, either in the testis or epididymal sperm (Shang et al, ; Shen et al, ). Therefore, PRSS37 and PRSS55, as serine proteases, were more likely to modulate the posttranslational modifications of ADAM3 during epididymal transit through an intermediate(s).…”

“…The levels of both CD52 and CD55 were significantly increased in KO mice, whereas both CD59b and SPAM-1 were reproducibly increased to lesser extents. ADAM, a disintegrin and metalloproteinase; GPI-AP, glycosylphosphatidylinositol-anchored protein; KO, knockout; PGAP1, post-GPI attachment to protein 1; t-ACE, testis ACE [Color figure can be viewed at wileyonlinelibrary.com] rates accompanied by a defect in sperm migration from the uterus into the oviduct in vivo, and the displayed sperm were incapable of sperm-egg recognition/binding in vitro (Figure 8; Shang et al, 2018;Shen et al, 2013). The main difference between PRSS37 and PRSS55 is that PRSS37 disappears during the late steps of spermatogenesis in the testis, whereas PRSS55 remains present in the mature sperm of the epididymis (Shang et al, 2018).…”

“…ADAM, a disintegrin and metalloproteinase; GPI-AP, glycosylphosphatidylinositol-anchored protein; KO, knockout; PGAP1, post-GPI attachment to protein 1; t-ACE, testis ACE [Color figure can be viewed at wileyonlinelibrary.com] rates accompanied by a defect in sperm migration from the uterus into the oviduct in vivo, and the displayed sperm were incapable of sperm-egg recognition/binding in vitro (Figure 8; Shang et al, 2018;Shen et al, 2013). The main difference between PRSS37 and PRSS55 is that PRSS37 disappears during the late steps of spermatogenesis in the testis, whereas PRSS55 remains present in the mature sperm of the epididymis (Shang et al, 2018). Moreover, the disruption of each of these proteins does not affect the expression level of the other in the testis and sperm or even during the epididymal sperm maturation process, indicating that PRSS37 and PRSS5 are independent of each other and that both proteins are located upstream of a downstream target(s), such as ADAM3 (Shang et al, 2018).…”