Science Collected Works - Research Publications
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ItemCorrection: HENMT1 and piRNA Stability Are Required for Adult Male Germ Cell Transposon Repression and to Define the Spermatogenic Program in the Mouse.(Public Library of Science (PLoS), 2015-12)
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ItemValidation and application of a novel integrated genetic screening method to a cohort of 1,112 men with idiopathic azoospermia or severe oligozoospermia(WILEY-HINDAWI, 2017-11)Microdeletions of the Y chromosome (YCMs), Klinefelter syndrome (47,XXY), and CFTR mutations are known genetic causes of severe male infertility, but the majority of cases remain idiopathic. Here, we describe a novel method using single molecule Molecular Inversion Probes (smMIPs), to screen infertile men for mutations and copy number variations affecting known disease genes. We designed a set of 4,525 smMIPs targeting the coding regions of causal (n = 6) and candidate (n = 101) male infertility genes. After extensive validation, we screened 1,112 idiopathic infertile men with non-obstructive azoospermia or severe oligozoospermia. In addition to five chromosome YCMs and six other sex chromosomal anomalies, we identified five patients with rare recessive mutations in CFTR as well as a patient with a rare heterozygous frameshift mutation in SYCP3 that may be of clinical relevance. This results in a genetic diagnosis in 11-17 patients (1%-1.5%), a yield that may increase significantly when more genes are confidently linked to male infertility. In conclusion, we developed a flexible and scalable method to reliably detect genetic causes of male infertility. The assay consolidates the detection of different types of genetic variation while increasing the diagnostic yield and detection precision at the same or lower price compared with currently used methods.
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ItemLong-term follow-up of intra-cytoplasmic sperm injection-conceived offspring compared with in vitro fertilization-conceived offspring: a systematic review of health outcomes beyond the neonatal period(WILEY, 2017-07)The use of intra-cytoplasmic sperm injection (ICSI) has increased significantly worldwide, often chosen instead of in vitro fertilization (IVF), yet long-term health outcomes are unknown and health differences between ICSI and IVF conceptions have not been comprehensively assessed. A systematic review of health outcomes of ICSI-conceived offspring beyond the neonatal period compared to IVF-conceived offspring was carried out. PubMed, OVID Medline/Embase, Informit, Web of Science and Proquest databases were searched on 9 November 2016 for studies reporting on health outcomes in ICSI-conceived offspring beyond 28 days after birth. Physical and psychosocial health were the main outcome measures. The search strategy yielded 2781 articles; 2539 were not relevant or did not meet inclusion criteria and 137 were duplicates. One hundred and five full-text papers were evaluated further and 34 satisfied the inclusion criteria. Studies comparing ICSI- and IVF-conceived children suggest their neurodevelopment is comparable. Growth and aspects of physical health are also similar; however, studies are few and limited to childhood. ICSI-conceived children may be at increased risk of autism and intellectual impairment. No difference in risk of childhood cancer was reported in one study. Whilst the neurodevelopment of ICSI-conceived children appears comparable to those of IVF conception, data relating to neurodevelopmental disorders, growth, physical health and childhood cancer are inconclusive. Further research into health outcomes in adolescence and adulthood is required before conclusions can be drawn about the long-term safety of ICSI compared to IVF. Until then, ICSI might be better reserved for its original intended use, male-factor infertility.
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ItemLong-term follow-up of ICSI-conceived offspring compared with spontaneously conceived offspring: a systematic review of health outcomes beyond the neonatal period(WILEY, 2018-09)BACKGROUND: A significant increase in the use of intracytoplasmic sperm injection (ICSI) since its introduction in 1992 has been observed worldwide, including beyond its original intended use for severe male factor infertility. Concerns regarding ICSI include the effects of poor quality spermatozoa on offspring health and future fertility, and of the technique itself. The health and development of ICSI-conceived children beyond early infancy have not been comprehensively assessed. OBJECTIVE: A systematic review of health outcomes of ICSI-conceived offspring beyond the neonatal period compared to spontaneously conceived (SC) offspring. DESIGN: PubMed, OVID Medline/Embase, InformIT, Web of Science, and ProQuest databases were searched for studies reporting on health outcomes in ICSI-conceived offspring beyond 28 days after birth. MAIN OUTCOMES MEASURE(S): Physical and psychosocial health. RESULTS: The search strategy yielded 2826 articles. Of these, 2580 were not relevant or did not meet inclusion criteria and 138 were duplicates. One hundred and eight full-text papers were evaluated further, and 48 satisfied the inclusion criteria. Most studies reported on neurodevelopment during early infancy and childhood with reassuring results. Growth, vision, and hearing of ICSI and SC offspring also appear comparable, although important differences in general physical health, and particularly metabolic and reproductive health have been described, including recently poorer semen quality among ICSI-conceived young adult men compared to SC peers. CONCLUSION: Whilst neurodevelopment, growth, vision, and hearing appear similar between ICSI and SC children, evidence suggests differences in general physical health, and metabolic and reproductive endpoints. The clinical significance of many findings, however, remains unclear, and further prospective, large, and good quality studies with a focus on all these health outcomes in ICSI-conceived young adults are required.
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ItemNo Preview AvailableAn Essential Role for Katanin p80 and Microtubule Severing in Male Gamete Production(PUBLIC LIBRARY SCIENCE, 2012-05)Katanin is an evolutionarily conserved microtubule-severing complex implicated in multiple aspects of microtubule dynamics. Katanin consists of a p60 severing enzyme and a p80 regulatory subunit. The p80 subunit is thought to regulate complex targeting and severing activity, but its precise role remains elusive. In lower-order species, the katanin complex has been shown to modulate mitotic and female meiotic spindle dynamics and flagella development. The in vivo function of katanin p80 in mammals is unknown. Here we show that katanin p80 is essential for male fertility. Specifically, through an analysis of a mouse loss-of-function allele (the Taily line), we demonstrate that katanin p80, most likely in association with p60, has an essential role in male meiotic spindle assembly and dissolution and the removal of midbody microtubules and, thus, cytokinesis. Katanin p80 also controls the formation, function, and dissolution of a microtubule structure intimately involved in defining sperm head shaping and sperm tail formation, the manchette, and plays a role in the formation of axoneme microtubules. Perturbed katanin p80 function, as evidenced in the Taily mouse, results in male sterility characterized by decreased sperm production, sperm with abnormal head shape, and a virtual absence of progressive motility. Collectively these data demonstrate that katanin p80 serves an essential and evolutionarily conserved role in several aspects of male germ cell development.
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ItemRare mutations in the complement regulatory gene CSMD1 are associated with male and female infertility(NATURE PUBLISHING GROUP, 2019-10-11)Infertility in men and women is a complex genetic trait with shared biological bases between the sexes. Here, we perform a series of rare variant analyses across 73,185 women and men to identify genes that contribute to primary gonadal dysfunction. We report CSMD1, a complement regulatory protein on chromosome 8p23, as a strong candidate locus in both sexes. We show that CSMD1 is enriched at the germ-cell/somatic-cell interface in both male and female gonads. Csmd1-knockout males show increased rates of infertility with significantly increased complement C3 protein deposition in the testes, accompanied by severe histological degeneration. Knockout females show significant reduction in ovarian quality and breeding success, as well as mammary branching impairment. Double knockout of Csmd1 and C3 causes non-additive reduction in breeding success, suggesting that CSMD1 and the complement pathway play an important role in the normal postnatal development of the gonads in both sexes.
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ItemSOX30 is required for male fertility in mice(NATURE PORTFOLIO, 2017-12-15)Male infertility is a major and growing problem and, in most cases, the specific root cause is unknown. Here we show that the transcription factor SOX30 plays a critical role in mouse spermatogenesis. Sox30-null mice are healthy and females are fertile, but males are sterile. In the absence of Sox30 meiosis initiates normally in both sexes but, in males, germ cell development arrests during the post-meiotic round spermatid period. In the mutant testis, acrosome and axoneme development are aberrant, multinucleated germ cells (symplasts) form and round spermatids unable to process beyond step 3 of spermiogenesis. No elongated spermatids nor spermatozoa are produced. Thus, Sox30 represents a rare example of a gene for which loss of function results in a complete arrest of spermatogenesis at the onset of spermiogenesis. Our results suggest that SOX30 mutations may underlie some instances of unexplained non-obstructive azoospermia in humans.
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ItemA mutation in the viral sensor 2′-5′-oligoadenylate synthetase 2 causes failure of lactation(PUBLIC LIBRARY SCIENCE, 2017-11)We identified a non-synonymous mutation in Oas2 (I405N), a sensor of viral double-stranded RNA, from an ENU-mutagenesis screen designed to discover new genes involved in mammary development. The mutation caused post-partum failure of lactation in healthy mice with otherwise normally developed mammary glands, characterized by greatly reduced milk protein synthesis coupled with epithelial cell death, inhibition of proliferation and a robust interferon response. Expression of mutant but not wild type Oas2 in cultured HC-11 or T47D mammary cells recapitulated the phenotypic and transcriptional effects observed in the mouse. The mutation activates the OAS2 pathway, demonstrated by a 34-fold increase in RNase L activity, and its effects were dependent on expression of RNase L and IRF7, proximal and distal pathway members. This is the first report of a viral recognition pathway regulating lactation.
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ItemPLAG1 deficiency impairs spermatogenesis and sperm motility in mice(NATURE PORTFOLIO, 2017-07-13)Deficiency in pleomorphic adenoma gene 1 (PLAG1) leads to reduced fertility in male mice, but the mechanism by which PLAG1 contributes to reproduction is unknown. To investigate the involvement of PLAG1 in testicular function, we determined (i) the spatial distribution of PLAG1 in the testis using X-gal staining; (ii) transcriptomic consequences of PLAG1 deficiency in knock-out and heterozygous mice compared to wild-type mice using RNA-seq; and (iii) morphological and functional consequences of PLAG1 deficiency by determining testicular histology, daily sperm production and sperm motility in knock-out and wild-type mice. PLAG1 was sparsely expressed in germ cells and in Sertoli cells. Genes known to be involved in spermatogenesis were downregulated in the testes of knock-out mice, as well as Hsd17b3, which encodes a key enzyme in androgen biosynthesis. In the absence of Plag1, a number of genes involved in immune processes and epididymis-specific genes were upregulated in the testes. Finally, loss of PLAG1 resulted in significantly lowered daily sperm production, in reduced sperm motility, and in several animals, in sloughing of the germinal epithelium. Our results demonstrate that the subfertility seen in male PLAG1-deficient mice is, at least in part, the result of significantly reduced sperm output and sperm motility.