Loss of Cep72 affects the morphology of spermatozoa in mice

PCM1 orchestrates centrosomal and flagellar protein transport to promote sperm maturation

Centriolar satellites facilitate the delivery of proteins required for centrosome assembly and function, and rely on the nucleation of the scaffold protein pericentriolar material 1 (PCM1). During sperm maturation, centrosomes undergo remodeling to facilitate neckpiece formation and flagellogenesis. However, the role and mechanism of PCM1 in centrosome remodeling and sperm maturation remain to be elucidated. Herein we show that PCM1 is downregulated in patients with non-obstructive azoospermia. Pcm1 knockout mice exhibit disrupted spermiogenesis, characterized by a disorganized manchette and head-tail coupling apparatus, defective flagellogenesis, and male infertility. Mechanistically, PCM1 binds centrosomal proteins and governs their precise translocation via intra-manchette transport, ensuring proper centrosome remodeling and axoneme biogenesis. Inactivation of PCM1 in sperm leads to severe retardation of embryo development, which cannot be overcome by intra-cytoplasmic sperm injection. Collectively, these findings establish PCM1 as a key regulator of spermatogenesis and spermiogenesis, highlighting the contribution of sperm centrosome-related proteins to embryo development and fertility.

CEP72 Emerges as a Key Centriolar Satellite Protein in Health and Disease

Centriolar satellites are membrane-less granules that are now accepted as core structural and functional components of the centrosomes and the cilia. While initially associated with centrosome assembly and primary cilia formation, these complexes and their dynamic structures seem to be involved in various other cellular processes, including protein homeostasis, autophagy, and responses to cellular stress. Since the identification of the first centriolar satellite protein, PCM1, substantial progress has been made in understanding the molecular composition and biological functions of centriolar satellites. Here, we review the function of a centriolar satellite protein CEP72, which is emerging as a key component of many essential processes associated with centrosomes and cilia. We describe the complexes it associates with, their function, and the genetic mutations that implicate CEP72 in a range of human disorders.

PWWP3A deficiency accelerates testicular senescence in aged mice

BACKGROUND

The PWWP domain-containing proteins are involved in chromatin-associated biological processes, including transcriptional regulation and DNA repair, and most of them are significant for gametogenesis and early embryonic development in mammals. PWWP3A, one of the PWWP domain proteins, is a reader of H3K36me2/H3K36me3 and a response factor to DNA damage. However, the physiological role of PWWP3A in spermatogenesis and fertility remains unclear.

OBJECTIVE

The goal of this study was to explore the function and mechanism of PWWP3A in the process of spermatogenesis.

MATERIALS AND METHODS

We generated V5-Pwwp3a KI mice and PWWP3A polyclonal antibody to observe the localization of PWWP3A in vivo. Meanwhile, Pwwp3a KO mice was used to explore the function in spermatogenesis.

RESULTS

We reported that PWWP3A is a predominant expression in the testis of mice. During spermatogenesis, PWWP3A exhibits the temporal expression from early-pachytene to the round spermatids. The results of spermatocyte spreading and immunostaining showed that PWWP3A aggregated on the XY body, which then diffused as the XY chromosome separated at late-diplotene. Although the depletion of PWWP3A had no obvious reproductive defects in young male mice, there were observed morphological abnormalities in sperm heads. Immunoprecipitation demonstrated the interaction of PWWP3A with DNA repair proteins SMC5/6; however, PWWP3A deficiency did not result in any meiotic defects. Notably, the testes of aged male Pwwp3a KO mice displayed pronounced degeneration, and were characterized by the presence of vacuolated seminiferous tubules. Furthermore, RNA-seq analysis revealed an upregulation in the expression of genes which may be involving in immunoregulatory and inflammatory response pathways in aged Pwwp3a KO mice with testicular degeneration.

CONCLUSIONS

Our study showed that PWWP3A was highly enriched in the mouse testis, and the Pwwp3a KO mice were fertile. However, the aged Pwwp3a KO male mice displayed testicular atrophy that may be due to changes in the immune micro-environment or abnormal repair of DNA damage.

Impact of air pollution from different sources on sperm DNA methylation

Environmental exposure is associated with increased incidence of respiratory and cardiovascular diseases and reduced fertility. Exposure to air pollution can influence gene expression through epigenetic mechanisms. In this study, we analysed gene-specific CpG methylation in spermatozoa of city policemen occupationally exposed to air pollution in two Czech cities differing by sources and composition of the air pollution. In Prague, the pollution is mainly formed by NO2 from heavy traffic. Ostrava is a hotspot of industrial air pollution with high concentrations of particular matter (PM) and benzo[a]pyrene (B[a]P). We performed genome-wide methylation sequencing using the SureSelectXT Human Methyl-Seq system (Agilent Technologies) and next-generation sequencing to reveal differentially methylated CpG sites and regions. We identified differential methylation in the region chr5:662169 - 663376 annotated to genes CEP72 and TPPP. The region was then analysed in sperm DNA from 117 policemen using targeted methylation sequencing, which proved its hypermethylation in sperm of Ostrava policemen.

Establishment of a zebrafish inbred strain, M-AB, capable of regular breeding and genetic manipulation

Inbred strains of organisms are genetically highly uniform and thus useful for life science research. We have previously reported the ongoing generation of the zebrafish IM strain from the India (IND) strain through full sib-pair mating for 16 generations. However, the IM fish laid a small number of offspring and had a short lifespan, implying the need for discreet care in breeding. Here, we report the subsequent establishment of IM strain as well as the generation of a new inbred zebrafish strain, Mishima-AB (M-AB). M-AB was derived from the *AB strain by full sib-pair mating for over 20 generations, which fulfills the general criterion for the establishment of an inbred strain. In contrast to the IM case, maintenance of the M-AB strain by sib-pair mating required almost no special handling. Genome sequencing of IM individuals from the 47th generation and M-AB individuals from the 27th generation revealed that SNP-based genomic heterogeneity across whole-genome nucleotides was 0.008% and 0.011%, respectively. These percentages were much lower than those of the parental IND (0.197%) and *AB (0.086%) strains. These results indicate that the genomes of these inbred strains were highly homogenous. We also demonstrated the successful microinjection of antisense morpholinos, CRISPR/Cas9, and foreign genes into M-AB embryos at the 1-cell stage. Overall, we report the establishment of a zebrafish inbred strain, M-AB, which is capable of regular breeding and genetic manipulation. This strain will be useful for the analysis of genetically susceptible phenotypes such as behaviors, microbiome features and drug susceptibility.