Talk:Genital System Development

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Genital Development

<pubmed limit=5>Genital Development</pubmed>

2018

Royal Hospital for Women - Reproductive Medicine Seminar 2018

Dr Rachael Rodgers Male and female reproductive/urogenital systems, breast, thyroid, adrenals, kidneys, hypothalamus and pituitary, it would be perfect.

It’s Rachael Rodgers here. I’m one of the fertility fellow / gynaecologists at the Royal Hospital for Women. I’m writing to ask if it would be possible for you to give a presentation on embryology at one of the teaching sessions we hold in the Reproductive Medicine department. Every second Tuesday morning, we have a teaching session in the Reproductive Medicine department that runs from 8-9am. The specialists, fellows, registrars, junior doctors and nurses from the Royal Hospital for Women attend, as well as some scientists from UNSW.

We would be very grateful if you would be able to give a lecture, Professor Ledger indicated to me that he thought you would be excellent. Specifically we were hoping that you could give a presentation on the embryonic development of the male and female reproductive structures (urogenital system primarily, also a brief mention of related structures such as the breast, urinary system, thyroid and adrenals if time permits). Our teaching restarts on 13th Feb, and then is held every second week after this.

Kind regards,

Dr Rachael Rodgers

BA, BSc, MBBS (Hons), MScMed (RHHG), FRANZCOG CREI Fellow / Gynaecology Senior Registrar Royal Hospital for Women Department of Reproductive Medicine Barker St, Randwick 2031 Phone: +61 402 136 657

2017

Anomalies in human sex determination provide unique insights into the complex genetic interactions of early gonad development

Clin Genet. 2017 Feb;91(2):143-156. doi: 10.1111/cge.12932.

Bashamboo A1, Eozenou C1, Rojo S1, McElreavey K1.

Abstract

Human sex determination (SD) involves complex mutually antagonistic genetic interactions of testis- and ovary-determining pathways. For many years, both male and female SD were considered to be regulated by a linear cascade of pro-male and pro-female genes, respectively; however, it has become clear that male and female development is achieved through the repression of the alternative state. A gene determining the formation of a testis may function by repressing the female state and vice versa. Uniquely in development, SD is achieved by suppression of the alternate fate and maintained in adulthood by a mutually antagonistic double-repressive pathway. Here, we review genetic data generated through large-scale sequencing approaches that are changing our view of how this system works, including the recently described recurrent NR5A1 p.R92W mutation associated with testis development in 46,XX children. We also review some of the unique challenges in the field to establish that mutations, such as this are pathogenic. The impending surge of new genetic data on human SD from sequencing projects will create opportunities for the development of mechanistic models that will clarify how the system operates and importantly provide data to understand how selection and developmental processes interact to direct the evolution of SD across species. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

KEYWORDS: NR5A1; cell-fate choice decisions; cellular models of human disease; disorders of sex development; gonadal dysgenesis; infertility; sex determination; testicular DSD PMID 27893151 DOI: 10.1111/cge.12932

2016

On the development of extragonadal and gonadal human germ cells

Biol Open. 2016 Feb 1;5(2):185-94. doi: 10.1242/bio.013847.

Heeren AM1, He N1, de Souza AF2, Goercharn-Ramlal A1, van Iperen L1, Roost MS1, Gomes Fernandes MM1, van der Westerlaken LA3, Chuva de Sousa Lopes SM4.

Abstract

Human germ cells originate in an extragonadal location and have to migrate to colonize the gonadal primordia at around seven weeks of gestation (W7, or five weeks post conception). Many germ cells are lost along the way and should enter apoptosis, but some escape and can give rise to extragonadal germ cell tumors. Due to the common somatic origin of gonads and adrenal cortex, we investigated whether ectopic germ cells were present in the human adrenals. Germ cells expressing DDX4 and/or POU5F1 were present in male and female human adrenals in the first and second trimester. However, in contrast to what has been described in mice, where 'adrenal' and 'ovarian' germ cells seem to enter meiosis in synchrony, we were unable to observe meiotic entry in human 'adrenal' germ cells until W22. By contrast, 'ovarian' germ cells at W22 showed a pronounced asynchronous meiotic entry. Interestingly, we observed that immature POU5F1+ germ cells in both first and second trimester ovaries still expressed the neural crest marker TUBB3, reminiscent of their migratory phase. Our findings highlight species-specific differences in early gametogenesis between mice and humans. We report the presence of a population of ectopic germ cells in the human adrenals during development. © 2016. Published by The Company of Biologists Ltd. KEYWORDS: Adrenals; Development; Ectopic; Fetal; Germ cells; Human; Meiosis; Ovaries

PMID 26834021

http://bio.biologists.org/content/5/2/185.long

2013

Fine time course expression analysis identifies cascades of activation and repression and maps a putative regulator of mammalian sex determination

PLoS Genet. 2013 Jul;9(7):e1003630. doi: 10.1371/journal.pgen.1003630. Epub 2013 Jul 11.

Munger SC, Natarajan A, Looger LL, Ohler U, Capel B. Source Department of Cell Biology, Duke University, Durham, North Carolina, USA.

Abstract

In vertebrates, primary sex determination refers to the decision within a bipotential organ precursor to differentiate as a testis or ovary. Bifurcation of organ fate begins between embryonic day (E) 11.0-E12.0 in mice and likely involves a dynamic transcription network that is poorly understood. To elucidate the first steps of sexual fate specification, we profiled the XX and XY gonad transcriptomes at fine granularity during this period and resolved cascades of gene activation and repression. C57BL/6J (B6) XY gonads showed a consistent ~5-hour delay in the activation of most male pathway genes and repression of female pathway genes relative to 129S1/SvImJ, which likely explains the sensitivity of the B6 strain to male-to-female sex reversal. Using this fine time course data, we predicted novel regulatory genes underlying expression QTLs (eQTLs) mapped in a previous study. To test predictions, we developed an in vitro gonad primary cell assay and optimized a lentivirus-based shRNA delivery method to silence candidate genes and quantify effects on putative targets. We provide strong evidence that Lmo4 (Lim-domain only 4) is a novel regulator of sex determination upstream of SF1 (Nr5a1), Sox9, Fgf9, and Col9a3. This approach can be readily applied to identify regulatory interactions in other systems.

PMID 23874228

2012

Mammalian sex determination—insights from humans and mice

Chromosome Res. 2012 Jan;20(1):215-38. doi: 10.1007/s10577-012-9274-3.

Eggers S, Sinclair A. Source Murdoch Children's Research Institute, Royal Children's Hospital and Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia.

Abstract

Disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Many of the genes required for gonad development have been identified by analysis of DSD patients. However, the use of knockout and transgenic mouse strains have contributed enormously to the study of gonad gene function and interactions within the development network. Although the genetic basis of mammalian sex determination and differentiation has advanced considerably in recent years, a majority of 46,XY gonadal dysgenesis patients still cannot be provided with an accurate diagnosis. Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. Here, we review our current knowledge of mammalian sex determination drawing on insights from human DSD patients and mouse models.

PMID 22290220

springeropen

Sex determination strategies in 2012: towards a common regulatory model?

Reprod Biol Endocrinol. 2012 Feb 22;10:13.

Angelopoulou R, Lavranos G, Manolakou P. Source Experimental Embryology Unit, Department of Histology and Embryology, Medical School, Athens University, Athens, Greece. rangelop@med.uoa.gr

Abstract

Sex determination is a complicated process involving large-scale modifications in gene expression affecting virtually every tissue in the body. Although the evolutionary origin of sex remains controversial, there is little doubt that it has developed as a process of optimizing metabolic control, as well as developmental and reproductive functions within a given setting of limited resources and environmental pressure. Evidence from various model organisms supports the view that sex determination may occur as a result of direct environmental induction or genetic regulation. The first process has been well documented in reptiles and fish, while the second is the classic case for avian species and mammals. Both of the latter have developed a variety of sex-specific/sex-related genes, which ultimately form a complete chromosome pair (sex chromosomes/gonosomes). Interestingly, combinations of environmental and genetic mechanisms have been described among different classes of animals, thus rendering the possibility of a unidirectional continuous evolutionary process from the one type of mechanism to the other unlikely. On the other hand, common elements appear throughout the animal kingdom, with regard to a) conserved key genes and b) a central role of sex steroid control as a prerequisite for ultimately normal sex differentiation. Studies in invertebrates also indicate a role of epigenetic chromatin modification, particularly with regard to alternative splicing options. This review summarizes current evidence from research in this hot field and signifies the need for further study of both normal hormonal regulators of sexual phenotype and patterns of environmental disruption. © 2012 Angelopoulou et al; licensee BioMed Central Ltd.

PMID 22357269

Table 1 - Regulatory elements in sex determination/dosage compensation Species Worms Insects Reptiles Amphibians Fish Birds Mammals Epigenetic phenomena unknown alternative splicing unknown unknown unknown unknown X inactivation Primary sex determination cellular all tissues gonad gonad gonad all tissues gonad Role of sex steroids unclear unclear sex det. sex diff. sex diff. sex diff. sex diff. Role of Temperature unclear TSD (rare) TSD TSD TSD none none Sex chromosomes X, W X(Y) ZZ/ZW ZZ/ZWXX/XY ZZ/ZW (Xenopus) XX/XYZZ/ZW ZZ/ZW XX/XY Sex determining gene(s) her-1, fem, tra SXL no DM-W DMY DMRT1 SRY Major regulatory elements in sex determination systems across the animal kingdom. Extensive similarities are noted even among distant species. Sex det: sex determination, Sex diff: Sex differentiation TSD: temperature-sensitive sex determination Angelopoulou et al. Reproductive Biology and Endocrinology 2012 10:13 doi:10.1186/1477-7827-10-13 2009 Development of the human Müllerian duct in the sexually undifferentiated stage An embryological explanation for the development of the Müllerian duct still poses a major challenge. The development of this duct was investigated systematically in human embryos. Seven embryos (Carnegie stages 18-23) were serially sectioned in the frontal, sagittal, and transversal planes at a thickness of 10 microm and stained with hematoxylin and eosin (H&E) for histological analysis. In all observed embryos, the caudal end of the Müllerian duct was found to be intimately connected to the Wolffian duct. The opening of the Müllerian duct to the coelomic cavity was formed as the result of an invagination of the coelomic epithelium at Carnegie stage 18. The duct grew independently from the invagination during stages 19-23. The fused duct (uterovaginal canal) bifurcated at the caudal portion at Carnegie stages 22 and 23. This is the first description of the caudal portion of the fused Müllerian ducts separating again and returning to each of the Wolffian ducts in human embryos. Copyright 2003 Wiley-Liss, Inc. PMID: 12740945 MicroRNA in the ovary and female reproductive tract Carletti MZ, Christenson LK. J Anim Sci. 2009 Apr;87(14 Suppl):E29-38. Epub 2008 Sep 12. Review. PMID: 18791135 "Interestingly, when Dicer1 expression is decreased in reproductive tissues or cells, the females are infertile." Meeting report: measuring endocrine-sensitive endpoints within the first years of life. Arbuckle TE, Hauser R, Swan SH, Mao CS, Longnecker MP, Main KM, Whyatt RM, Mendola P, Legrand M, Rovet J, Till C, Wade M, Jarrell J, Matthews S, Van Vliet G, Bornehag CG, Mieusset R. Environ Health Perspect. 2008 Jul;116(7):948-51. PMID: 18629319 | PMC: 2453165] | Supplementary PDF "An international workshop titled "Assessing Endocrine-Related Endpoints within the First Years of Life" was held 30 April-1 May 2007, in Ottawa, Ontario, Canada. Representatives from a number of pregnancy cohort studies in North America and Europe presented options for measuring various endocrine-sensitive endpoints in early life and discussed issues related to performing and using those measures. The workshop focused on measuring reproductive tract developmental endpoints [e.g., anogenital distance (AGD)], endocrine status, and infant anthropometry. To the extent possible, workshop participants strove to develop or recommend standardized measurements that would allow comparisons and pooling of data across studies. The recommended outcomes include thigh fat fold, breast size, vaginal cytology, AGD, location of the testis, testicular size, and growth of the penis, with most of the discussion focusing on the genital exam. Although a number of outcome measures recommended during the genital exam have been associated with exposure to endocrine-disrupting chemicals, little is known about how predictive these effects are of later reproductive health or other chronic health conditions." Anogenital distance from birth to 2 years: a population study Environ Health Perspect. 2009 Nov;117(11):1786-90. Epub 2009 Jul 13. Thankamony A, Ong KK, Dunger DB, Acerini CL, Hughes IA. Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom. Abstract BACKGROUND: Anogenital distance (AGD) is sexually dimorphic in rodents and humans, being 2- to 2.5-fold greater in males. It is a reliable marker of androgen and antiandrogen effects in rodent reproductive toxicologic studies. Data on AGD in humans are sparse, with no longitudinal data collected during infancy. OBJECTIVE: This study was designed to determine AGD from birth to 2 years in males and females and relate this to other anthropometric measures. MATERIALS AND METHODS: Infants were recruited from the Cambridge Baby Growth Study. AGD was measured from the center of the anus to the base of the scrotum in males and to the posterior fourchette in females. Measurements were performed at birth and at 3, 12, 18, and 24 months of age. RESULTS: Data included 2,168 longitudinal AGD measurements from 463 male and 426 female full-term infants (median = 2 measurements per infant). Mean AGD (+/- SD) at birth was 19.8 +/- 6.1 mm in males and 9.1 +/- 2.8 mm in females (p < 0.0001). AGD increased up to 12 months in both sexes and in a sex-dimorphic pattern. AGD was positively correlated with penile length at birth (r = 0.18, p = 0.003) and the increase in AGD from birth to 3 months was correlated with penile growth (r = 0.20, p = 0.001). CONCLUSION: We report novel, longitudinal data for AGD during infancy in a large U.K. birth cohort. AGD was sex dimorphic at all ages studied. The availability of normative data provides a means of utilizing this biological marker of androgen action in population studies of the effects of environmental chemicals on genital development. PMID: 20049133 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2801188/?tool=pubmed