CEP250 is Required for Maintaining Centrosome Cohesion in the Germline and Fertility in Male Mice

Function of manchette and intra-manchette transport in spermatogenesis and male fertility

The manchette is a transient skirt-like structure consisting of microtubules (MTs) and filamentous actin (F-actin) surrounding the elongating sperm head during spermiogenesis. It is pivotal in sperm head shaping controlled by the acrosome-acroplaxome-manchette complex, acrosome formation, and flagellar assembly by microtubular-based protein delivery. Defects in the manchette frequently lead to teratozoospermia concomitant with oligozoospermia and asthenozoospermia, but the pathogenic mechanism underlying manchette function and its role in male infertility remain poorly understood. In this review, we systematically described the assembly and disassembly of the manchette, intra-manchette transport (IMT) and its regulatory model, the function and mechanism of manchette and IMT in regulating sperm head shaping and flagellar assembly during spermatogenesis; summarized the research progress of manchette-related genes related to male infertility; and listed the manchette-related proteins in knockout mouse models and clinical cases, which provide the theoretical basis for an in-depth understanding of the molecular mechanism of manchette involved in spermatogenesis and male fertility for understanding the potentially developing treatments for infertility and reproductive disorders.

Proteomic Characterization of Extracellular Vesicles from Human Neural Precursor Cells: A Promising Advanced Therapy for Neurodegenerative Diseases

Background

The therapeutic effect of stem cells is attributed to their direct maturation into somatic cells and their paracrine effects, which influence the extracellular environment. One such component released is extracellular vesicles containing proteins and genetic materials with immunomodulatory functions and facilitating cell-to-cell communication.

Purpose

The study's main objective was to characterize extracellular vesicles (EVs) from Human Neural Precursor Cells (hNPCs).

Methods

Wharton's Jelly mesenchymal stem cells (WJ-MSCs) were isolated by explant technique and characterized by flow cytometry and trilineage differentiation. The hNPCs obtained from neurospheres were produced by seeding WJ-MSCs on a natural functional biopolymer matrix. EVs derived from WJ-MSCs and hNPCs were isolated by precipitation methodology and characterized by flow cytometry, nanoparticle tracking analysis (NTA), scanning electron microscopy (TEM), and proteomic.

Results

hNPCs expressed proteins and genes characteristic of neural precursor cells. The EVs were characterized by flow cytometry and showed varied expression for the markers CD63, CD9, and CD81, indicating different subpopulations based on their origin of formation. NTA and TEM of the EVs exhibited characteristic size, shape, and structural integrity consistent with the criteria established by the International Society for Extracellular Vesicles (ISEV). EV-hNPCs function enrichment analysis of the proteomic results showed that these vesicles presented abundant proteins directly involved in neuronal biological processes such as plasticity, transduction, postsynaptic density, and overall brain development.

Discussion

The results indicate that EVs derived from hNPCs maintain key neural precursor characteristics and exhibit marker variability, suggesting distinct subpopulations. Their structural integrity aligns with ISEV standards, supporting their potential as reliable biological entities. The proteomic analysis highlights their role in neuronal functions, reinforcing their applicability in neurodegenerative research and therapeutic strategies.

Conclusion

The EVs were successfully isolated from hNPCs with abundant proteins involved in neuronal processes, making them attractive for acellular therapies to treat neurodegenerative diseases.

Loss of Cep135 causes oligoasthenoteratozoospermia and male infertility in mice

Centrosomal proteins (Cep), as crucial scaffolding molecules, play a pivotal role in the biogenesis of centrioles and the regulation of the cell cycle. To date, mutation in Cep135 has been reported to be closely associated with multiple morphological abnormalities of the flagella (MMAF) in humans. However, the specific mechanism of Cep135 in spermatogenesis and its detailed role in male infertility remains largely unexplored. In this study, we present compelling evidence that Cep135 functions as a pathogenic gene responsible for oligoasthenoteratozoospermia (OAT) and male infertility in mice. By selectively deleting Cep135 in premeiotic germ cells using Stra8-Cre mice crossed with Cep135flox/flox mice, we observed that Cep135 knockdown produced abnormal sperm morphology, germ cell apoptosis and consequentlybecame complete infertility, but did not impact premeiosis. Scanning and transmission electron microscopy revealed defects in acrosome, flagellum, and head-to-tail connections during spermatogenesis. Proteomic analysis further indicated that CEP135 deletion led to a significant reduction in proteins mainly associated with acrosome formation, sperm heads, sperm flagellum and microtubule assembly. Additionally, CEP135 interacts with spermatogenic proteins SPATA6 and AKAP3, regulating their expression and stability. Deficiency in CEP135 or its interacting proteins resulted in ciliary shortening. In conclusion, our study profoundly unveils the central role of Cep135 in spermatogenesis and male fertility. This discovery not only deepens our comprehension of spermatogenesis but also furnishes a solid theoretical foundation and experimental evidence that can guide the formulation of therapeutic and preventive strategies for male infertility.

Multiomics analysis provides insights into musk secretion in muskrat and musk deer

BACKGROUND

Musk, secreted by the musk gland of adult male musk-secreting mammals, holds significant pharmaceutical and cosmetic potential. However, understanding the molecular mechanisms of musk secretion remains limited, largely due to the lack of comprehensive multiomics analyses and available platforms for relevant species, such as muskrat (Ondatra zibethicus Linnaeus) and Chinese forest musk deer (Moschus berezovskii Flerov).

RESULTS

We generated chromosome-level genome assemblies for the 2 species of muskrat (Ondatra zibethicus Linnaeus) and musk deer (Moschus berezovskii Flerov), along with 168 transcriptomes from various muskrat tissues. Comparative analysis with 11 other vertebrate genomes revealed genes and amino acid sites with signs of adaptive convergent evolution, primarily linked to lipid metabolism, cell cycle regulation, protein binding, and immunity. Single-cell RNA sequencing in muskrat musk glands identified increased acinar/glandular epithelial cells during secretion, highlighting the role of lipometabolism in gland development and evolution. Additionally, we developed MuskDB (http://muskdb.cn/home/), a freely accessible multiomics database platform for musk-secreting mammals.

CONCLUSIONS

The study concludes that the evolution of musk secretion in muskrats and musk deer is likely driven by lipid metabolism and cell specialization. This underscores the complexity of the musk gland and calls for further investigation into musk secretion-specific genetic variants.

Emerging roles of centrosome cohesion

The centrosome, consisting of centrioles and the associated pericentriolar material, is the main microtubule-organizing centre (MTOC) in animal cells. During most of interphase, the two centrosomes of a cell are joined together by centrosome cohesion into one MTOC. The most dominant element of centrosome cohesion is the centrosome linker, an interdigitating, fibrous network formed by the protein C-Nap1 anchoring a number of coiled-coil proteins including rootletin to the proximal end of centrioles. Alternatively, centrosomes can be kept together by the action of the minus end directed kinesin motor protein KIFC3 that works on interdigitating microtubules organized by both centrosomes and probably by the actin network. Although cells connect the two interphase centrosomes by several mechanisms into one MTOC, the general importance of centrosome cohesion, particularly for an organism, is still largely unclear. In this article, we review the functions of the centrosome linker and discuss how centrosome cohesion defects can lead to diseases.

Centrosome linker protein C-Nap1 maintains stem cells in mouse testes

The centrosome linker component C-Nap1 (encoded by CEP250) anchors filaments to centrioles that provide centrosome cohesion by connecting the two centrosomes of an interphase cell into a single microtubule organizing unit. The role of the centrosome linker during development of an animal remains enigmatic. Here, we show that male CEP250-/- mice are sterile because sperm production is abolished. Premature centrosome separation means that germ stem cells in CEP250-/- mice fail to establish an E-cadherin polarity mark and are unable to maintain the older mother centrosome on the basal site of the seminiferous tubules. This failure prompts premature stem cell differentiation in expense of germ stem cell expansion. The concomitant induction of apoptosis triggers the complete depletion of germ stem cells and consequently infertility. Our study reveals a role for centrosome cohesion in asymmetric cell division, stem cell maintenance, and fertility.