Identification of side population cells in mouse primordial germ cells and prenatal testis

In mammals, the stem cells of spermatogenesis are derived from an embryonic cell population called primordial germ cells (PGCs). Spermatogonial stem cells displaying the "side population" (SP) phenotype have been identified in the immature and adult mouse testis, but noting is known about the expression of the SP phenotype during prenatal development of germ cells. The SP phenotype, defined as the ability of cells to efflux fluorescent dyes such as Hoechst, is common to several stem/progenitor cell types. In the present study, we analyzed and characterized the Hoechst SP via cytofluorimetric analysis of disaggregated gonads at different time points during embryonic development in mice. To directly test the hypothesis that the SP phenotype is a feature of germ cell lineage, experiments were performed on transgenic animals expressing enhanced green fluorescent protein (EGFP) under the control of the Oct4 promoter, to identify early germ cells up to PGCs. We found that prenatal gonads contain a fraction of SP cells at each stage analyzed, and the percentage of cells in the SP fraction decreases as development proceeds. Surprisingly, more than 50% of the PGCs displayed the SP phenotype at 11.5 dpc (days post coitum). The percentage of germ cells with the SP phenotype decreased steadily with development, to less than 1% at 18.5 dpc. Cytofluorimetric analysis along with immunocytochemistry performed on sorted cells indicated that the SP fraction of prenatal gonads, as in the adult testis, was heterogeneous, being composed of both somatic and germ cells. Both cell types expressed the ABC transporters Abcg2, Abcb1a, Abcb1b and Abcc1. These findings provide evidence that the SP phenotype is a common feature of PGCs and identifies a subpopulation of fetal testis cells including prospermatogonia whose differentiation fate remains to be investigated. © 2011 UBC Press

Sorafenib maintenance after hematopoietic stem cell transplantation improves outcome of FLT3-ITD-mutated acute myeloid leukemia

In a retrospective analysis, 21 acute myeloid leukemia patients receiving single-agent sorafenib maintenance therapy in complete remission (CR) after hematopoietic stem cell transplantation (HSCT) were compared with a control group of 22 patients without maintenance. Sorafenib was initiated a median of 3 months (IQR: 2.3–3.5) after allogeneic HSCT with a median daily dosage of 400 mg (range: 200–800) orally, and lasted a median of 11.3 months (IQR: 3.3–24.4). No significant increase in graft versus host disease or toxicity was observed. Adverse events were reversible with dose adjustment or temporary discontinuation in 19/19 cases. With a median follow-up of 34.7 months (IQR: 16.9–79.5), sorafenib maintenance significantly improved cumulative incidence of relapse (p = 0.028) as well as overall survival (OS) (p = 0.016), especially in patients undergoing allogeneic HSCT in CR1 (p < 0.001). In conclusion, sorafenib maintenance after allogeneic HSCT is safe and may improve cumulative incidence of relapse and OS in FLT3–ITD-mutated AML. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12185-022-03427-4

82. Cftr Gene Targeting in Murine ES Cells Mediated by the SFHR Technique

Small Fragment Homologous Recombination (SFHR)-mediated targeting is a gene therapy strategy where a specific genomic locus is modified through a target exchange between a small DNA fragment (SDF) and genomic DNA. Here we demonstrate that SFHR can stably introduce a 3-bp deletion (corresponding to |[Delta]|F508) within Cftr (Cystic Fibrosis Transmembrane Conductance Regulator) locus in the genome of mouse embryonic stem (ES) cells. SDFs (about 6.4|[times]|105 molecules per cell) carrying the |[Delta]|F508 mutation were transfected by nucleofection protocol. About 12% of transcript corresponding to deleted allele was detected and about 60% of the electroporated cells no longer had measurable CFTR-dependent chloride efflux. The CFTR activity was also analyzed by measuring the chloride efflux by the fluorescence microscopy-coupled digital video imaging system in each ES cell colony, previously loaded with MQAE, a chloride sensitive dye. An average of 4-6 regions for each cell colony was analysed to verify the genotypic homogeneity of each colony. In fact all regions examined in each colony showed a similar significant chloride efflux after PKA activation. Moreover on twelve electroporated ES colonies analysed, eight were successfully mutated (Cl- efflux not significantly different from zero) while four colonies showed Cl-efflux CFTR-dependent not significantly different from the untreated ones

Myogenic potential of mouse primordial germ cells

Primordial germ cells are the only stem cells that retain true developmental totipotency after gastrulation, express markers typical of totipotent/pluripotent status and are able both in vivo and in vitro to give rise to pluripotent stem cells as EC and EG cells. We have therefore explored the possibility of the trans-differentiation of mouse PGCs to a myogenic lineage by transplanting them directly or after in vitro culture into a regenerating muscle and by culturing them on monolayers of differentianting muscle cells. The results obtained suggest that mouse PGCs may trans-differentiate into myogenic cells, provided that their somatic environment is preserved. This occurs at an estimated frequency of 0.01%, which is no higher than that reported for stem cells of adult tissues

Prognostic performance of the 'DICA' endoscopic classification and the 'CODA' score in predicting clinical outcomes of diverticular disease: an international, multicentre, prospective cohort study

To investigate the predictive value of the Diverticular Inflammation and Complication Assessment (DICA) classification and to develop and validate a combined endoscopic-clinical score predicting clinical outcomes of diverticulosis, named Combined Overview on Diverticular Assessment (CODA)

Establishment of oocyte population in the fetal ovary: Primordial germ cell proliferation and oocyte programmed cell death

Strict control of cell proliferation and cell loss is essential for the coordinated functions of different cell populations in complex multicellular organisms. Oogenesis is characterized by a first phase occurring during embryo-fetal life and in common with spermatogenesis, during which mitotic proliferation of the germline stem cells, the primordial germ cells (PGC), prevails over germ cell death. The result is the formation of a relatively high number of germ cells depending on the species, ready to enter sex specific differentiation. In the female, PGC enter into meiosis and become oocytes, thereby ending their stem cell potential. After entering into meiosis in the fetal ovary, oocytes pass through leptotene, zygotene and pachytene stages before arresting in the last stage of meiotic prophase I, the diplotene or dictyate stage at about the time of birth. The most part of oocytes die during the fetal period or shortly after birth. It is widely accepted that in mammals a female is born with a fixed number of oocytes within the ovaries, which over the years progressively decreases without possibility for renewal. Once the oocyte reserve has been exhausted, ovarian senescence, driving what is referred to as the menopause in women, rapidly ensues. The fertile lifespan of a female depends by the size of the oocyte pool at birth and the rapidity of the oocyte pool depletion. Which mechanisms control PGC proliferation? Why do most of the oocytes die during fetal life and what are the mechanisms of such massive degeneration? Is it possible to prolong the lifespan of a female by reducing oocyte lost during the fetal life? This review reports some of the most recent results obtained in an attempt to answer these questions

Asthma in patients admitted to emergency department for COVID-19: prevalence and risk of hospitalization

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