Arrdc4‐dependent extracellular vesicle biogenesis is required for sperm maturation

Abstract

Extracellular vesicles (EVs) are important players in cell to cell communication in reproductive systems. Notably, EVs have been found and characterized in the male reproductive tract, however, direct functional evidence for their importance in mediating sperm function is lacking. We have previously demonstrated that Arrdc4, a member of the α‐arrestin protein family, is involved in extracellular vesicle biogenesis and release. Here we show that Arrdc4‐mediated extracellular vesicle biogenesis is required for proper sperm function. Sperm from Arrdc4–/– mice develop normally through the testis but fail to acquire adequate motility and fertilization capabilities through the epididymis, as observed by reduced motility, premature acrosome reaction, reduction in zona pellucida binding and two‐cell embryo production. We found a significant reduction in extracellular vesicle production by Arrdc4–/‐ epididymal epithelial cells, and further, supplementation of Arrdc4–/– sperm with additional vesicles dampened the acrosome reaction defect and restored zona pellucida binding. These results indicate that Arrdc4 is important for proper sperm maturation through the control of extracellular vesicle biogenesis.

The glucose-sensing transcription factor MLX balances metabolism and stress to suppress apoptosis and maintain spermatogenesis

“…While TXNIP is highly expressed in human Sertoli cells ( S4E Fig ), the protein decreases in both GCs and Sertoli cells in the MLX KO , suggestive of MLX activity in both compartments. Consistent with this, another MondoA-MLX target, ARRDC4 , is highly expressed in GC compared with Sertoli cells ( S4F Fig ), and Arrdc4 was recently demonstrated to support murine sperm maturation in vivo [ 29 ]. Given the widespread expression of MLX in the testis ( Fig 2A and 2B ), we reasoned that MLX loss is likely to have a cell autonomous effect on GC differentiation and spermiogenesis and decided to focus our further investigation on the whole body MLX KO .…”

“…This suggests that critical MLX transcriptional targets in addition to TXNIP are responsible for the majority of the male-specific sterility phenotypes associated with loss of either MLX or MondoA. An example of such is Arrdc4 , a bona fide MondoA-MLX target, bound by MLX in our dataset, and it has recently been shown to be required for normal male fertility in the mouse [ 29 ].…”

K‐29 linked ubiquitination of Arrdc4 regulates its function in extracellular vesicle biogenesis

“…We observed a significant increase in the number of EVs (100–200 nm size) released by Arrdc4 WT compared with vector control cells as expected (Figure S3B ). As Arrdc4 mostly regulates a specific subset of EVs in the >100 nm size (Foot et al., 2021 ) we used this range (EV 100‐ 200nm ) for all further analyses. Arrdc4 K270R was the only mutant to show a significant decrease in the number of EV 100‐ 200 nm released from the cells compared to Arrdc4 WT (Figures 2g and S3B ).…”

“…However, the Arrdc4‐dependent EV release may involve a different mechanism than Arrdc1 (Mackenzie et al., 2016 ). Using the Arrdc4 –/– mice, Arrdc4 was also found to be important for maturation of sperm through the control of EV biogenesis (Foot et al., 2021 ). Although Arrdc1 and Arrdc4 are E3 adaptors and Nedd4 family members appear to be involved in Arrdc1 and Arrdc4 dependent EV biogenesis, the precise role of ubiquitination of these adaptors in the regulation of EV biogenesis by these proteins remains unknown.…”

Genome-Wide Association Studies, Runs of Homozygosity Analysis, and Copy Number Variation Detection to Identify Reproduction-Related Genes in Bama Xiang Pigs

“…Gene SLC26A8 is a sperm-specific member of the SLC26 family, and its heterozygous missense mutations are highly associated (power of >95%) with asthenozoospermia ( 40 ). Gene ARRDC 4 mediates extracellular vesicle biogenesis, which appears to be required for sperm function, given that ARRDC4 KO mice have impaired sperm ( 41 ). Two of the 18 genes were related to ovaries, follicles, and female infertility.…”