Cry1 deficiency leads to testicular dysfunction and altered expression of genes involved in cell communication, chromatin reorganization, spermatogenesis, and immune response in mouse testis

Abstract

Cryptochrome (Cry)1 is essential for generating circadian rhythm in central and many peripheral oscillators; however, its role in male reproduction remains unclear. We investigated this question using Cry1 knockout (KO) mice. We found that Cry1 is necessary for normal testicular function: Cry1 deficiency increased testicular germ cell apoptosis and decreased sperm count. A transcriptome analysis showed that the expression levels of 375 genes-including 12 encoding micro (mi)RNAs-were altered in the testis of Cry1 KO mice relative to wild-type controls. A bioinformatics analysis revealed that the differentially expressed genes were related to important biological processes including cell-cell communication, metabolism, chromatin reorganization, spermatogenesis, and the immune response. An integrative analysis of miRNA-mRNA networks suggested that the 12 dysregulated miRNAs may contribute to testis disorders through negative regulation of their target mRNAs expression in testis, and interestingly, all the 12 miRNAs are predicted to target core circadian clock components. These results provide the first evidence of a correlation between dysregulation of Cry1 and male reproductive defects in mice, indicating that Cry1 plays a critical role in maintaining normal testicular function.

Clock genes and cancer development in particular in endocrine tissues

“…CRY1 is necessary for normal testicular function: CRY1 deficiency increased testicular germ cell apoptosis and decreased sperm count (Li et al 2018). BMAL1 protein is exclusively expressed in mouse Leydig cells.…”

Circadian Clock-Controlled Checkpoints in the Pathogenesis of Complex Disease

“…Mechanistically, BMAL1 and CLOCK regulate the assembly of chromatoid bodies through interaction with MVH, a key component of the sperm chromatoid body ( Peruquetti et al, 2012 ). A deficiency of Cry1 was found to increase apoptosis of mouse testicular germ cells and decrease sperm count ( Li C. et al, 2018 ). Sertoli cells provide a nurturing and supportive niche for spermatogenesis.…”

“…It is not clear whether disruption of the homologous recombination can also be induced by BMAL1, but the expression of core clock genes including BMAL1 is altered in the mouse testis ( Liu K. et al, 2020 ). Twelve micro (mi)RNA are altered in the testes of Cry1 mutant mice, all of which are predicted to target the components of the core clock ( Li C. et al, 2018 ). These findings deserve further confirmation under different exposure conditions.…”

Chronodisruption: effects on reproduction, transgenerational health of offspring and epigenome

“…In a study of CLOCK knockdown in mice with small hairpin RNA, a significant reduction in offspring from these males was observed (Liang et al 2013). In addition, Cry1 KO mice have perturbed spermatogenesis with increased number of degenerate and apoptotic germ cells in the testis and lower epididymal sperm counts (Li et al 2018). Bioinformatic analysis reveals that the differentially expressed genes are involved in important biological processes including cell-cell communication, metabolism, chromatin reorganization, spermatogenesis, and the immune response, indicating that Cry1 is important for normal testicular function (Li et al 2018).…”

“…Animal studies Alvarez et al (2003) C57BL/6 mice Non-circadian roles in spermatogenesis Morse et al (2003) Clock c/c mutant mice, Per -/mice, CREM -/mice Non-circadian roles in spermatogenesis Liang et al (2013) CLOCK knockdown in testis/mice Li et al (2018) Cry1 knockout mice Cry1 required for normal testicular function Alvarez et al (2003) C57BL/6 mice Circadian regulation important for sperm maturation and stability Bebas et al (2009) C57BL/6 mice Alvarez et al (2008) Bmal1 knockout mice Bmal1 involvement in testosterone production and fertility Mereness et al (2015) PER2::LUC transgenic mice Association with androgen and circadian gene expression Liang et al (2013) CLOCK knockdown in testis/mice Reduced fertility Cheng et al (2016) CLOCK knockdown in testis/mice 2012). Clock mutation also disrupts the ability to complete pregnancy (Miller et al 2004).…”