DREF Genetically Counteracts Mi-2 and Caf1 to Regulate Adult Stem Cell Maintenance.

Active adult stem cells maintain a bipotential state with progeny able to either self-renew or initiate differentiation depending on extrinsic signals from the surrounding microenvironment. However, the intrinsic gene regulatory networks and chromatin states that allow adult stem cells to make these cell fate choices are not entirely understood. Here we show that the transcription factor DNA Replication-related Element Factor (DREF) regulates adult stem cell maintenance in the Drosophila male germline. A temperature-sensitive allele of DREF described in this study genetically separated a role for DREF in germline stem cell self-renewal from the general roles of DREF in cell proliferation. The DREF temperature-sensitive allele caused defects in germline stem cell self-renewal but allowed viability and division of germline stem cells as well as cell viability, growth and division of somatic cyst stem cells in the testes and cells in the Drosophila eye. Germline stem cells mutant for the temperature sensitive DREF allele exhibited lower activation of a TGF-beta reporter, and their progeny turned on expression of the differentiation factor Bam prematurely. Results of genetic interaction analyses revealed that Mi-2 and Caf1/p55, components of the Nucleosome Remodeling and Deacetylase (NuRD) complex, genetically antagonize the role of DREF in germline stem cell maintenance. Taken together, these data suggest that DREF contributes to intrinsic components of the germline stem cell regulatory network that maintains competence to self-renew.

A distinct isoform of ZNF207 controls self-renewal and pluripotency of human embryonic stem cells.

Self-renewal and pluripotency in human embryonic stem cells (hESCs) depends upon the function of a remarkably small number of master transcription factors (TFs) that include OCT4, SOX2, and NANOG. Endogenous factors that regulate and maintain the expression of master TFs in hESCs remain largely unknown and/or uncharacterized. Here, we use a genome-wide, proteomics approach to identify proteins associated with the OCT4 enhancer. We identify known OCT4 regulators, plus a subset of potential regulators including a zinc finger protein, ZNF207, that plays diverse roles during development. In hESCs, ZNF207 partners with master pluripotency TFs to govern self-renewal and pluripotency while simultaneously controlling commitment of cells towards ectoderm through direct regulation of neuronal TFs, including OTX2. The distinct roles of ZNF207 during differentiation occur via isoform switching. Thus, a distinct isoform of ZNF207 functions in hESCs at the nexus that balances pluripotency and differentiation to ectoderm.

A PAX5-OCT4-PRDM1 developmental switch specifies human primordial germ cells.

Dysregulation of genetic pathways during human germ cell development leads to infertility. Here, we analysed bona fide human primordial germ cells (hPGCs) to probe the developmental genetics of human germ cell specification and differentiation. We examined the distribution of OCT4 occupancy in hPGCs relative to human embryonic stem cells (hESCs). We demonstrated that development, from pluripotent stem cells to germ cells, is driven by switching partners with OCT4 from SOX2 to PAX5 and PRDM1. Gain- and loss-of-function studies revealed that PAX5 encodes a critical regulator of hPGC development. Moreover, an epistasis analysis indicated that PAX5 acts upstream of OCT4 and PRDM1. The PAX5-OCT4-PRDM1 proteins form a core transcriptional network that activates germline and represses somatic programmes during human germ cell differentiation. These findings illustrate the power of combined genome editing, cell differentiation and engraftment for probing human developmental genetics that have historically been difficult to study.

Transcriptional comparison of human induced and primary midbrain dopaminergic neurons.

Generation of induced dopaminergic (iDA) neurons may provide a significant step forward towards cell replacement therapy for Parkinson's disease (PD). To study and compare transcriptional programs of induced cells versus primary DA neurons is a preliminary step towards characterizing human iDA neurons. We have optimized a protocol to efficiently generate iDA neurons from human pluripotent stem cells (hPSCs). We then sequenced the transcriptomes of iDA neurons derived from 6 different hPSC lines and compared them to that of primary midbrain (mDA) neurons. We identified a small subset of genes with altered expression in derived iDA neurons from patients with Parkinson's Disease (PD). We also observed that iDA neurons differ significantly from primary mDA neurons in global gene expression, especially in genes related to neuron maturation level. Results suggest iDA neurons from patient iPSCs could be useful for basic and translational studies, including in vitro modeling of PD. However, further refinement of methods of induction and maturation of neurons may better recapitulate full development of mDA neurons from hPSCs.

DDX3Y gene rescue of a Y chromosome AZFa deletion restores germ cell formation and transcriptional programs.

Deletions of the AZFa region (AZoospermia Factor-a) region of the human Y chromosome cause irreversible spermatogenic failure that presents clinically in men as Sertoli-cell only (SCO) pathology of the testis. Deletions of the AZFa region typically encompass two genes: DDX3Y and USP9Y. However, human genetic evidence indicates that SCO is most tightly linked to deletion of DDX3Y and that deletions/mutations of USP9Y can be transmitted from one generation to the next. Here, we generated stable iPSC lines with AZFa deletions, tested complementation via introduction of DDX3Y, and assessed ability to form germ cells in vivo in a xenotransplantation model. We observed a quantifiable improvement in formation of germ cell like cells (GCLCs) from complemented donor iPSCs. Moreover, expression of UTF1, a prospermatogonial protein, was restored in cells complemented by introduction of DDX3Y on the AZFa background. Whole-genome RNA sequencing of purified GCLCs revealed an enrichment of genes involved in translational suppression and transcriptional control in DDX3Y-rescued GCLCs over mutant GCLCs, which maintained a molecular phenotype more similar to undifferentiated iPSCs. This study demonstrates the ability to probe fundamental genetics of human germ cell formation by complementation and indicates that DDX3Y functions in the earliest stages of human germ cell development.

[Repeated ectopic pregnancy in previous caesarean scar: a case report and literature review]. / Embarazo ectópico repetido en cicatriz de-cesárea previa: reporte de un caso y revisión bibliográfica.

BACKGROUND: Ectopic pregnancy in previous caesarean scar, which is detected in the first trimester, is a recognized and documented today alteration. CLINICAL CASE: Female of 38 years old with a history of five pregnancies (two cesarean sections and three ectopic pregnancies, two EPCSS and one tubal ectopic). In March 2013 she presented the first eight weeks EPCSS diagnosed by transvaginal ultrasound. Gestational sac at the level of the previous cesarean section (CS) over the inner hole and a living embryo were observed. The patient received medical treatment with methotrexate. In March 2014 she was diagnosed with a new tubal ectopic pregnancy which was managed with laparoscopic salpingectomy. In February 2015 (Second EPCSS) she was checked for seven weeks amenorrhea and symptoms of pregnancy. A vaginal ultrasound was performed, finding a gestational sac implanted in the lower uterine segment cesarean scar level and a living embryo. The patient undergoing laparoscopic hysterectomy. CONCLUSION: The recurrent pregnancy caesarean section scar is rare and needs to be properly diagnosed as soon as possible to avoid complications. Transvaginal ultrasound is a suitable tool for diagnosis. Management must be individualized according to patient characteristics.