Loss-of-function mutations in IQCN cause male infertility in humans and mice owing to total fertilization failure.

Fertilization failure is a significant manifestation of unexplained male infertility. Previous work has suggested a genetic origin. In this study, we report on a man with unexplained infertility from a large consanguineous marriage family. Whole-exome sequencing and Sanger sequencing identified a homozygous frameshift variation of the IQ motif containing N (IQCN; GenBank: NM_001145304.1; c.1061_1062delAT; p.Y354Sfs*13) in the proband and one of his two brothers, who also remained infertile. Analyses of spermatozoa by quantitative RT-PCR indicated that the level of IQCN mRNA was significantly reduced compared to fertile men and the protein could not be detected by western blotting and immunofluorescent staining in the proband. Immunofluorescent staining of spermatozoa from fertile men showed that IQCN was located in the acrosomal region and translocated to the equatorial segment after the acrosome reaction. The proband spermatozoa had abnormal morphology and function. Finally, the proband couple underwent IVF with donor sperm and a healthy baby was born. Furthermore, we developed an Iqcn-KO mouse model using the CRISPR/Cas9 technique. Sperm quality, except for sperm motility, and the fertility of male Iqcn-/- mice were consistent with those of the proband. In conclusion, the findings in humans and mice demonstrate that the homozygous frameshift variant of IQCN causes male infertility owing to autosomal-recessive fertilization failure.

Pathogenesis of acephalic spermatozoa syndrome caused by SUN5 variant.

Acephalic spermatozoa syndrome (ASS) is a rare teratozoospermia that leads to male infertility. Previous work suggested a genetic origin. Variants of Sad1 and UNC84 domain containing 5 (SUN5) are the main genetic cause of ASS; however, its pathogenesis remains unclear. Here, we performed whole-exome sequencing in 10 unrelated ASS and identified 2 homozygous variants, c.381delA[p.V128Sfs7*] and c.675C>A[p.Y225X], and 1 compound variant, c.88 C > T[p.R30X] and c.381 delA [p.V128Sfs7*], in SUN5 in 4 patients. The c.381delA variant had been identified as pathogenic in previous reports, while c.675C>A and c.88 C > T were two novel variants which could lead to a premature termination codon (PTC) and resulted in loss of SUN5, and may also be pathogenic. SUN5 mRNA and protein were present at very low levels in ASS patients with SUN5 nonsense mutation. Furthermore, the distribution of outer dense fiber protein 1 (ODF1) and Nesprin3 was altered in sperm of ASS patients with SUN5 variants. The co-immunoprecipitation analysis indicated that SUN5 and ODF1, SUN5 and Nesprin3, and ODF1 and Nesprin3 interacted with each other in transfected HEK293T cells. Thus, we propose that SUN5, Nesprin3, and ODF1 may form a 'triplet' structure through interactions at neck of sperm. When gene variants resulted in a loss of SUN5, the 'triplet' structure disappears and then the head-tail junction becomes fragile, leading to the occurrence of ASS.

Long noncoding RNA maternally expressed gene 3 knockdown alleviates lipopolysaccharide-induced inflammatory injury by up-regulation of miR-203 in ATDC5 cells.

BACKGROUND: Osteoarthritis (OA) is a common degenerative joint disease, which seriously impacts the health of elderly. However, there is no effective treatment for curing this disease until now. Numerous studies reported that long noncoding RNAs (lncRNAs) are closely related to the pathogenesis of OA. Therefore, the study aims to investigate the effect of maternally expressed gene 3 (MEG3) on lipopolysaccharide (LPS)-induced inflammatory injury of ATDC5 cells. METHODS: Different concentrations (0, 1, 5, and 10 µg/ml) of LPS were used to induce ATDC5 cells injury. The specific expressing vectors were then transfected into ATDC5 cells to alter MEG3, Sirt1 and miR-203 expressions. Flow cytometry, luciferase reporter, qRT-PCR and western blot assays were used to detect cell viability, apoptosis, and the expressions of apoptosis-related proteins and pro-inflammatory factors (IL-1ß, IL-6, IL-8 and TNF-α). Meanwhile, ELISA was used for analyzing the concentrations of inflammatory cytokines in culture supernatant. Besides, the key pathways of PI3K/AKT and NF-κB were examined by western blot. RESULTS: LPS decreased cell viability, increased cell apoptosis, promoted the release of pro-inflammatory factors, and down-regulated MEG3 expression, Moreover, MEG3 knockdown alleviated LPS-induced inflammatory injury. MEG3 acted as a competing endogenous RNAs (ceRNA) for miR-203, and MEG3 knockdown reduced inflammatory injury by regulating miR-203. Furthermore, miR-203 positively regulated Sirt1 expression, and Sirt1 alleviated LPS-induced inflammatory injury via mediating PI3K/AKT and NF-κB pathways. CONCLUSION: This study showed that MEG3 knockdown alleviated LPS-induced inflammatory injury in ATDC5 cells by regulating miR-203 expression. Hence, the findings may offer a potential treatment perspective of OA.