1,721,424 research outputs found
Stem cell factor and leukemia inhibitory factor promote primordial germ cell survival by suppressing programmed cell death (apoptosis)
No full textProliferating primordial germ cells (PGCs) isolated from mouse embryos soon after their arrival in the genital ridges would only survive in vitro at temperature of less than 30 degrees C (De Felici, M. and McLaren, A. (1983). Exp. Cell. Res. 144, 417-427; Wabik-Sliz, B. and McLaren, A. (1984). Exp. Cell. Res. 154, 530-536) or when co-cultured on cell feeder layers (Donovan, P. J., Stott, D., Godin, I., Heasman, J. and Wylie, C. C. (1986). Cell 44, 831-838; De Felici, M. and Dolci, S. (1991). Dev. Biol. 147, 281-284). In the present paper we report that mouse PGC death in vitro occurs with all the hallmarks of programmed cell death or apoptosis. We found that after 4-5 hours in culture many PGCs isolated from 12.5 dpc fetal gonads assumed a nuclear morphology and produced membrane bound fragments (apoptotic bodies) typical of apoptotic cells. In addition, PGCs in culture accumulated high level of tissue transglutaminase (tTGase; an enzyme that is induced and activated during apoptosis) and showed extensive degradation of DNA to oligonucleosomal fragments, which is characteristic of apoptosis. The physiological relevance of this mechanism of PGC death is supported by the finding that some PGCs undergoing apoptosis, as revealed by the high level of tTGase expression, were detected in the embryo. Most importantly, we show that the addition of stem cell factor (SCF) or leukemia inhibitory factor (LIF) to the culture medium, two cytokines known to favour PGC survival and/or proliferation in vitro, markedly reduced the occurrence of apoptosis in PGCs during the first hours in culture.(ABSTRACT TRUNCATED AT 250 WORDS
Regulation of primordial germ cell development in the mouse
No full textPrimordial germ cells (PGCs) are the founders of the gametes. They arise at the earliest stages of embryonic development and migrate to the gonadal ridges, where they differentiate into oogonia/oocytes in the ovary, and prospermatogonia in the testis. The present article is a review of the main studies undertaken by the author with the aim of clarifying the mechanisms underlying the development of primordial germ cells. Methods for the isolation and purification of migratory and post-migratory mouse PGCs devised in the author's laboratory are first briefly reviewed. Such methods, together with the primary culture of PGCs onto suitable cell feeder layers, have allowed the analysis of important aspects of the control of their development, concerning in particular survival, proliferation and migration of mouse PGCs. Compounds and growth factors affecting PGC numbers in culture have been identified. These include survival anti-apoptotic factors (SCF, LIF) and positive regulators of proliferation (cAMP, PACAPs, RA). Evidence has been provided that the motility of migrating PGCs relies on integrated signals from extracellular matrix molecules and the surrounding somatic cells. Moreover, homotypic PGC-PGC interaction has been evidenced that might play a role in PGC migration and in regulating their development. Several molecules (i.e. integrins, specific types of oligosaccharides, E-cadherin, the tyrosine kinase receptor c-kit) have been found to be expressed on the surface of PGCs and to mediate adhesive interactions of PGCs with the extracellular matrix, somatic cells and neighbouring PGCs
Mixing in a Stirred Vessel. A Parallel Implementation with Lattice Boltzmann Colored Particles Model
No full textThe main purpose of this paper is to present a new method for the study of single fluid
mixing in a stirred vessel. The simulation has been realized with a parallel implementation of the
Lattice Boltzmann coloured particles model. The mixing phenomenon is compared with the one
derived with a Lagrangian approach
Twenty years of research on primordial germ cells
No full textJust twenty years ago I was preparing a research project centred on establishing methods for the isolation and culture of mouse primordial germ cells (PGCs). The project had been suggested to me by Anne McLaren and was to be developed at the Medical Research Council (MRC) "Mammalian Development Unit" in London under the direction of Anne herself. At that time I was a young postdoctoral researcher at the Institute of Histology and Embryology of the University of Rome "La Sapienza" and did not imagine that my decision to be involved in this project would signal a profound switch in my scientific life. From then on my research would mostly concentrate on primordial germ cell biology. I feel like saying that the modern history of mammalian primordial germ cells began twenty years ago at the MRC Mammalian Development Unit under Anne McLaren's impulse. It is not surprising that among the most active researchers in the last twenty years in studying mammalian primordial germ cells, three, namely Chris Wylie, Peter Donovan and myself, began their studies under Anne McLaren's guidance. Over the years, Anne's suggestions and encouragement were always precious for my studies and her presence marked my most important findings on PGC biology. She often invited me to present the results obtained in my laboratory to workshops and congresses. In the present article some of these results particularly influenced by Anne's teaching and suggestions will be briefly reviewed
Primordial germ cell biology at the beginning of the XXI Century
Full text linkAt the XIV Workshop on the Development and Function of the Reproductive Organs held at the Congress Centre of the University of Rome Tor Vergata, Monteporzio Catone, Rome, Italy, the introduction to the first session entitled "Mammalian primordial germ cells" dedicated to the memory of Anne McLaren, was the occasion for a concise review of the state of art of research on the biology of primordial germ cells (PGCs). This great, unforgettable scientist, who died in a car accident in July 2007, dedicated most of her studies to this field over the last 25 years. Topics briefly reviewed in this Meeting Report are: 1) how the germ line is determined; 2) what are the mechanisms underlying PGC migration; 3) to what extent PGC survival, proliferation and differentiation are cell autonomous or environmentally controlled processes and 4) how the potential for totipotency is retained in PGCs
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