P-524 Bi-allelic CFAP61 variants cause male infertility in humans and mice with severe oligoasthenoteratozoospermia

Study question

Are mutations in cilia and flagella-associated protein 61 (CFAP61) associated with human male infertility?

Summary answer

Bi-allelic variants ([NM_015585.4: c.1654C>T (p.R552C) and c.2911G>A (p.D971N), c.144-2A>G and c.1666G>A (p.G556R)] in CFAP61 were identified as contributory genetics factor in severe oligoasthenoteratozoospermia (OAT).

What is known already

Cfap61 knockout mice were infertile due to multiple morphological abnormalities of the sperm flagella (MMAF). However, so far there is no direct evidence that mutations of CFAP61 cause OAT and male infertility.

Study design, size, duration

Variant screening was performed by whole-exome sequencing (WES) from 325 infertile patients with OAT and 392 fertile individuals. A knockout mouse model was generate to confirm the candidate disease-causing gene, intracytoplasmic sperm injection (ICSI) was used to evaluate the efficiency of clinical treatment.

Participants/materials, setting, methods

A total 325 OAT-affected patients and 392 men with normal fertility were recruited from China. WES was performed, followed by Sanger sequencing validation. In silico bioinformatics predictions and in vitro functional analyses were performed to evaluate the impacts of candidate disease-causing variants. Hematoxylin and eosin (H&E) staining, electron microscopy, and immunofluorescence assays were performed to evaluate the sperm morphology. Two OAT-affected men with CFAP61 variants were treated by ICSI, and pregnancy outcomes were followed.

Main results and the role of chance

We identified bi-allelic CFAP61 variants [NM_015585.4: c.1654C>T (p.R552C) and c.2911G>A (p.D971N), c.144-2A>G and c.1666G>A (p.G556R)] in two (0.62%) of the 325 OAT-affected men. In silico bioinformatics analysis predicted that all four variants were deleterious, and in vitro functional analysis confirmed the deleterious effects of the mutants. Notably, H&E staining and electron microscopy analyses of the spermatozoa revealed multiple morphological abnormalities of sperm flagella, the absence of central pair microtubules, and mitochondrial sheath malformation in sperm flagella from man with CFAP61 variants. Further immunofluorescence assays revealed markedly reduced CFAP61 staining in the sperm flagella. In addition, Cfap61-deficient mice showed the OAT phenotype, suggesting that loss of function of CFAP61 was the cause of OAT. Two individuals accepted ICSI therapy using their own ejaculated sperm, and one of them succeeded in fathering a healthy baby.

Limitations, reasons for caution

Limitations include the lack of in vivo data from the one of patients, and the exact molecular mechanism should be further investigated.

Wider implications of the findings

Our findings indicate that CFAP61 is essential for spermatogenesis and that bi-allelic CFAP61 variants lead to OAT and male infertility in humans and mice. In addition, our results show that ICSI treatment can be recommended for CFAP61-related OAT.

Trial registration number

not applicable

Dendritic cell TLR4 induces Th1-type immune response against Cryptosporidium parvum infection

The objective of this study was to investigate the mechanism of Toll-like receptor (TLR4)- mediated dendritic cell (DC) immune against Cryptosporidium parvum infection. C. parvum sporozoites were labeled with 5,6-carboxyfluorescein diacetate succinimidyl ester. Murine bone marrow-derived DCs were isolated, and divided into TLR4 antibody blocking (TAB; infected with 2 × 10⁵ labeled sporozoites and 0.5 μg TLR4 blocking antibody), TLR4 antibody unblocking (TAU; infected with 2 × 10⁵ labeled sporozoites), and blank control (BC; with 1.5 mL Roswell Park Memorial Institute 1640 medium) groups. The adhesion of Cryptosporidium sporozoites to DCs and CD11c⁺ levels were examined by fluorescence microscopy and flow cytometry. Male KM mice were orally injected with C. parvum. The proliferation of T lymphocytes in spleen, expression of cytokines in peripheral blood, and TLR4 distribution features in different organs were further determined by immunohistochemistry. A significantly higher expression of CD11c⁺ and higher C. parvum sporozoite adhesion were found in the TAU group compared with other groups. The expression of CD4⁺CD8^- /CD8⁺CD4^- in the spleen were obviously differences between the TAB and TAU groups. The expression of TLR4, interleukin IL-4, IL-12, IL-18 and IFN-γ improved in the TAU group compared with TAB group. Higher expression of TLR4 was detected in the lymph nodes of mice in the TAU group, with pathological changes in the small intestine. Hence, TLR4 could mediate DCs to recognize C. parvum, inducing Th1 immune reaction to control C. parvum infection.

Missense mutation in DNAJB13 gene correlated with male fertility in asthenozoospermia

BACKGROUND

The most common type of male infertility is asthenospermia. We cloned DnaJ heat shock protein family member B13 (Dnajb13/DNAJB13), a type II HSP40 family member that is highly expressed in the testis. DNAJB13 plays a crucial role in sperm flagellar function.

OBJECTIVES

The aim of this study was to investigate whether a correlation exists between DNAJB13 and low sperm motility in infertile men.

MATERIALS AND METHODS

In the present study, we performed a mutation screening of the DNAJB13 gene in 92 idiopathic asthenozoospermia patients and 200 men with normal fertility. Additionally, we used immunoelectron microscopy, co-immunoprecipitation, mass spectrometric detection, indirect immunofluorescence assay, transmission electron microscopy studies, isobaric tags for relative and absolute quantitation, and multiple reaction monitoring studies to analyze changes in DNAJB13 protein.

RESULTS

A novel c.106T>C mutation of DNAJB13 was present in nearly 10% (9/92) of idiopathic asthenozoospermia patients and was absent in 200 fertile men. A computer-assisted sperm analyzer and transmission electron microscopy analysis using samples from 9 patients with DNAJB13 mutations demonstrated that most spermatozoa were immotile due to sperm tail defects. Multiple reaction monitoring results indicated that DNAJB13 protein levels were reduced after gene mutation. We achieved a pregnancy rate of 100% in 8 patients with DNAJB13 mutations using ICSI.

DISCUSSION AND CONCLUSION

The DNAJB13 heterozygous variant may affect fertility. ICSI can help these patients with low fertility to father children.

Using SNP array to identify aneuploidy and segmental imbalance in translocation carriers

Translocation is one of the more common structural rearrangements of chromosomes, with a prevalence of 0.2%. The two most common types of chromosomal translocations, Robertsonian and reciprocal, usually result in no obvious phenotypic abnormalities when balanced. However, these are still associated with reproductive risks, such as infertility, spontaneous abortion and the delivery of babies with mental retardation or developmental delay.

In recent years, array-based whole-genome amplification (WGA) technologies, including microarray comparative genomic hybridization (array CGH; aCGH) and single-nucleotide polymorphism (SNP) micro-arrays, have enabled the screening of every chromosome for whole-chromosome aneuploidy and segmental imbalance. These techniques have been shown to have clinical application for translocation carriers. Promising studies have indicated that array-based PGD of translocation carriers can lead to transfer pregnancy rates of 45–70% [2].

In addition to genetic testing techniques, the embryo biopsy stage (polar body, cleavage embryo or blastocyst) and the mode of embryo transfer (fresh or frozen embryos) can affect the outcome of PGD. It is now generally recommended that blastomere biopsy should be replaced by blastocyst biopsy to avoid a high mosaic rate and biopsy-related damage to cleavage-stage embryos, which might affect embryo development. However, more clinical data are required to confirm that the technique of SNP array-based PGD (SNP-PGD) combined with trophectoderm (TE) biopsy and frozen embryo transfer (FET) is superior to traditional FISH-PGD combined with Day 3 (D3) blastomere biopsy and fresh embryo transfer.

Value of transvaginal sonography in diagnosing heterotopic pregnancy after in-vitro fertilization with embryo transfer

OBJECTIVES

To assess the value of transvaginal sonography (TVS) in the diagnosis of heterotopic pregnancy (HP) in the first trimester after in-vitro fertilization with embryo transfer (IVF-ET).

METHODS

This was a retrospective review of women undergoing IVF-ET between January 2005 and December 2011. Women were diagnosed with an HP using TVS if a visible intrauterine gestational sac was observed with any of the following: (i) an inhomogeneous adnexal mass; (ii) an empty extrauterine gestational sac seen as a hyperechoic ring; or (iii) a yolk sac and/or fetal pole with or without cardiac activity in an extrauterine sac.

RESULTS

Overall, 16 483 consecutive women who underwent IVF had TVS during the study. Of these, 174 cases were diagnosed on TVS as having an HP, and 10 cases were missed. Fifty-two cases were treated expectantly and were excluded from the analysis. Three types of ultrasonographic presentation of ectopic pregnancy (EP) were seen in HP patients, with a gestational sac found in 70 cases, a ring sign in 21 and an adnexal mass in 31. The sensitivity and specificity of TVS for the detection of HP were 92.4 and 100%, respectively, with positive and negative predictive values of 100 and 99.9%. The HP cases comprised 103 tubal EPs and 29 non-tubal EPs. In 93 patients (70.5%), their intrauterine pregnancy resulted in a live birth, 37 patients (28.0%) suffered an early miscarriage and two patients (1.5%) had a late miscarriage.

CONCLUSION

Early TVS performed by an experienced sonographer has a high sensitivity for making the correct diagnosis of HP after IVF-ET.

Association of AR rs6152G/A gene polymorphism with susceptibility to polycystic ovary syndrome in Chinese women

Hyperandrogenism is a central feature of polycystic ovary syndrome (PCOS). Androgens act via the androgen receptor (AR). The rs6152G/A AR gene polymorphism has been reported to be associated with male pattern baldness (MPB), which is a common characteristic of males in PCOS families. Therefore, we investigated the relationship between the rs6152G/A polymorphism and PCOS in Han Chinese women. The rs6152G/A AR gene polymorphism was screened by restriction fragment length polymorphism (RFLP) in 224 PCOS women and 223 control subjects from the Reproductive and Genetic Hospital of CITIC-XIANGYA in China. There was a significantly higher prevalence of genotypes containing the A allele in PCOS patients compared with controls (P < 0.05). Patients carrying the rs6152A allele had a 1.608-fold greater risk of developing polycystic ovary syndrome compared with rs6152GG homozygotes (OR = 1.608, CI = 1.008-2.597, P < 0.05). In conclusion, the individuals carrying the rs6152A allele had significantly higher susceptibility to polycystic ovary syndrome than those that were GG homozygotes.

How medical ethical principles are applied in treatment with artificial insemination by donors (AID) in Hunan, China: effective practice at the Reproductive and Genetic Hospital of CITIC-Xiangya

This paper investigates the efficiency of application of medical ethics principles in the practice of artificial insemination by donors (AID) in China, in a culture characterised by traditional ethical values and disapproval of AID. The paper presents the ethical approach to AID treatment as established by the Reproduction and Genetics Hospital of CITIC-Xiangya (CITIC Hunan-Yale Approach) in the central southern area of China against the social ethical background of China and describes its general features. The CITIC-Xiangya Approach facilitates the implementation of ethical relations between clinicians and patients participating in AID treatment procedures in Hunan-Yale.

Cloning of a novel gene,Cymg1, related to family 2 cystatins and expressed at specific stages of mouse testis development

We have cloned a novel gene, Cymg1 (GenBank accession number AY600990), from a mouse testis cDNA library. Cymg1 is located in 2G3 of mouse chromosome 2. The cDNA includes an open reading frame that encodes 141 amino acid residues. The encoded polypeptide has a cysteine protease inhibitor domain found in the family 2 cystatins but lacks critical consensus sites important for cysteine protease inhibition. These characteristics are seen in the proteins of the CRES subfamily of the family 2 cystatins which are expressed specifically in the reproductive tract. CYMG1 protein shows 44% identity with mouse CRES and 30% identity with mouse cystatin C. Northern blot analysis showed that the Cymg1 gene was specifically expressed in adult mouse testis. RT-PCR also showed that Cymg1 was expressed in testis and spermatogonial cells. Cymg1 expression level varied in the different developmental stages of mouse testis, and were coincidental with spermatogenesis and sex maturation. These results indicate that Cymg1 may play important roles in mouse spermatogenesis and sex maturation.

[Rapid identification of human testis spermatocyte apoptosis-related gene, TSARG2, by nested PCR and draft human genome searching]

Cloning apoptosis-related novel genes is a key to further understanding of apoptosis mechanism and the biology process of germ cells, and is of momentous significance on clarifying physiological and pathological process of spermatogenesis. To rapidly attain human novel gene full-length cDNA sequence, the gene-specific primers and the vector-specific primers were designed for nested PCR, and draft human genome searching was performed to rapidly identify the TSARG2 (GenBank accession number AY040204) 5' end from a human testis cDNA library, by using a cDNA fragment (GenBank accession number BE644542) as an electronic probe, which was significantly changed in cryptorchidism and represented a novel gene. Furthermore, a mouse homologue of this gene was identified (GenBank accession number AF395083) by lab on-line. TSARG2 with a 1 233 bp length was composed of 6 exons and spanned about 115 kb of genomic DNA, The putative protein encoded by this gene was 305 amino acid with a theoretical molecular weight of 34 751 dalton and did not share significant homology with any known protein in databases. TSARG2 was expressed in many tissues and mapped to chromosome 4q33-34.1 by database analyses. Therefore, we propose that nested-PCR and draft human genome searching are rapid, sensitive, accurate and efficient method for isolating gene 5' end, even full-length gene from cDNA library.

[Localization and position effect of human APPSWE gene on transgenic mice by means of in situ fluorescence hybridization]

In situ fluorescence hybridization (FISH) was used to study the integration and localization of human APPSWE gene on chromosomes of transgenic mice. It was found that in 2 founder mice, 34 and 36 metaphases of 80 metaphases observed had shown obvious specific hybridizing signals, the detection rates were 42.5% and 45%, respectively; meanwhile, in 1 F1 and 1 F2 mice, 33 and 30 metaphases out of 100 metaphases observed had specific hybridizing signals, the detection rates were 33% and 30%, respectively. The transgenes were localized on chromosome 8, 1, 17 and 2. The results indicated that transgene APPSWE were integrated stably into the chromosomes of transgenic mice and could be transmitted to offsprings through germ cells. The transgenes were randomly integrated into multiple sites of mice chromosomes. Meanwhile, the phenotypes of transgenic mice were also studied and different integrated sites had obvious effects on the pheonotypes.

[Establishment of two-dimensional gel electrophoretic protein map of human spermatozoa]

OBJECTIVE

To establish the method of 2-dimensional electrophoresis(2-DE) for proteins of human spermatozoa and to construct a protein map of human spermatozoa.

METHODS

The sperm pellet was prepared with simple Percoll layer protocol. We studied the effects of various sample preparation methods, loading quantities and isoelectric-focusing protocols on the quality of silver-stained 2-DE map, and constructed a primary protein map of human spermatozoa.

RESULT

Up to 703 protein spots were acquired with sample preparation Method I while only 194-210 spots with Method II. With immobilized pH gradients and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(IPG-DALT) we could acquire over 700 spots while only 280-300 with isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(ISO-DALT).

CONCLUSION

It is satisfactory to lyse sperm with sample preparation Method I and to separate sperm proteins by IPG-DALT for establishing 2-D map of human sperm.

[Establishment of the data base of large human sperm bank and its application]

On the basis of Access 97, we set up the first computer management system for human sperm bank in China, which dealt with various information and data of sperm bank and of treatment for AID(artificial insemination donor) patients. The system and its application, characteristics and significance were discussed in this article.