Planar cell polarity (PCP) proteins and spermatogenesis

Abstract

In adult mammalian testes, spermatogenesis is composed of several discrete cellular events that work in tandem to support the transformation and differentiation of diploid spermatogonia to haploid spermatids during the seminiferous epithelial cycle. These include: self-renewal of spermatogonial stem cells via mitosis and their transformation into differentiated spermatogonia, meiosis I/II, spermiogenesis and the release of sperms at spermiation. Studies have shown that these cellular events are under precise and coordinated controls of multiple proteins and signaling pathways. These events are also regulated by polarity proteins that are known to confer classical apico-basal (A/B) polarity in other epithelia. Furthermore, spermatid development is likely supported by planar cell polarity (PCP) proteins since polarized spermatids are aligned across the plane of seminiferous epithelium in an orderly fashion, analogous to hair cells in the cochlea of the inner ear. Thus, the maximal number of spermatids can be packed and supported by a fixed population of differentiated Sertoli cells in adult testes in the limited space of the seminiferous epithelium. In this review, we briefly summarize recent findings regarding the role of PCP proteins in the testis. This information should be helpful in future studies to better understand the role of PCP proteins in spermatogenesis.

Gene Polymorphisms in Boar Spermatozoa and Their Associations with Post-Thaw Semen Quality

“…However, our results provide evidence indicating that boars with the homologous AA genotype at rs345056502 (EML5 gene) were more susceptible to post-thaw acrosome damage and LPO, while the homologous TT genotype of the PRICKLE1 gene contributed to greater cryo-induced DNA damage. Moreover, microtubule-associated proteins (MAPs) in sperm cells have various functions including modulation of actin cytoskeletal function during spermatogenesis [49]. Collectively, EML5 and PRICKLE1 are implicated in microtubule (MT) dynamics in the testis, and mutations in their genotypes could affect the physiological and structural function of the sperm following cryopreservation.…”

Vangl2 regulates spermatid planar cell polarity through microtubule (MT)-based cytoskeleton in the rat testis

“…For instance, the release of sperm takes place at stage VIII of the cycle, coinciding with the appearance of step 8 spermatids and the preleptotene spermatocytes in the seminiferous epithelium. PCP refers to the orderly alignment of a field of polarized cells within the plane of an epithelium such as those found in wing cell hair in Drosophila and cell hair of the inner ear in mammals 15 , 23 , 32 . Using confocal microscopy, developing spermatids in particular step 17–19 spermatids in stage V–VIII tubules were found to display PCP in the reconstructed 3D image such as the one shown in Fig.…”

“…Recently, we have reported elongating/elongated spermatids also displayed PCP in adult rat testes in which the proximal end of polarized spermatid heads were aligned uniformly across the plane of the seminiferous epithelium by confocal microscopy and 3-dimensional (D) reconstruction of the seminiferous tubules 28 . Studies also have identified several PCP genes/proteins in the mammalian testis 29 – 32 . Among these, Vangl2 was found to regulate the apical ES at the spermatid-Sertoli cell interface and at the Sertoli cell–cell interface at the blood-testis barrier (BTB) called basal ES 31 .…”

Molecular mechanisms mediating asymmetric subcellular localisation of the core planar polarity pathway proteins

“…Planar polarity has been reported from as early as epiblast formation in zebrafish [ 5 ] and primitive endoderm formation in mouse [ 6 ]. Its loss is implicated in neural tube closure defects [ 7 ], spermatogenesis defects [ 8 ], deafness [ 9 ], and heart defects [ 10 ]. As such the underlying mechanisms are of broad interest.…”