Stem Cells and Organoid Biology

ESR project

1.6

Title of Project

In vitro bovine follicle culture and embryo culture

We offer

A 4-year PhD student position in the interdisciplinary area of regenerative medicine. Your project will focus on in vitro follicle and embryo development

We ask

You hold a Master’s degree in Biology or in a related area. You have affinity with cell biology and embryology and thrive in a multidisciplinary research environment. Experience with cell culture is of benefit.

Department

The Department of Farm Animal Health at the Faculty of Veterinary Medicine, Utrecht University in Utrecht, the Netherlands

Description

Due to the progress that has been made in early detection and therapies, the survival rates of cancer patients have increased significantly. Unfortunately however the treatment itself can lead to health problems later in life. Female survivors of childhood adolescent and young adult cancer may suffer from infertility during adulthood as a result of the anti-cancer therapy. Decrease in fertility may be caused be decrease in ovarian follicle numbers leading to absence of puberty or premature ovarian insufficiency. The main method to preserve fertility in these patients is cryopreservation of ovarian tissue before the treatment. Little data are available however about which part of the ovary can be best cryopreserved, the quantity of tissue to be cryopreserved and possibilities of reintroducing malignant cells with autotransplantation of preserved tissues after treatment. In vitro growth and maturation of follicles culture and subsequent in vitro fertilization (IVF) would eliminate the possibility of reintroducing malignant cells.

Although in vitro follicle development has been successful with mouse ovaries, culture of human follicles is much more difficult among other due to the longer time of development (months opposed to weeks), the scarcity of material for research and ethical and legal difficulties.. Bovine ovarian follicle development is very similar to that of the human in terms of timing and ovulation kinetics, and therefore provides a good model system. Most importantly, ample ovaries are available from the slaughterhouses. This project is aimed at primary follicle isolation and in vitro culture using different substrates (Matrigel/ hydrogels etc). Preliminary data suggest that primordial follicles can be successfully isolated from ovarian tissue using both enzymatic and mechanical disruption.

In mammalian embryos, including human embryos, the gastrulation process (exit from pluripotency and formation of the three definitive germ layers) is poorly understood as this occurs after implantation into the womb. Most knowledge available is from mouse embryos, but these have a unique embryo shape (cup-shaped) that is not comparable with the planar morphology of human and for instance cattle embryos.

Fertilization of human oocytes followed by in vitro culture of embryos for research only is not allowed in many European countries including the Netherlands.  In addition, in vitro culture of human embryos that is allowed, with leftover embryos after informed consent and approval by the ethics committee is only allowed for a maximum of 14 days. Indeed human embryos have recently been cultured for 14 days, but although technically possible to continue culture, this was legally not possible (Shahbazi et al. Nat Cell Biol. 2016;18:700-708; Deglincerti et al.Nature. 2016;533:251-4). Therefore much information about remodeling of the embryos, including gastrulation, shortly after implantation remains mysterious. Knowledge of these processes and for instance signaling pathways involved would be beneficial for those that study tissue and organ formation in the field of regenerative medicine.

Cattle embryos can be efficiently generated in large quantities (hundreds per week) by in vitro fertilization of oocytes obtained from slaughterhouse ovaries. Collection of the ovaries and culture of the embryos are not considered animal experiments, and there is no limitation on the duration of in vitro embryo culture. The similarities in early embryo development (planar morphology) between human and cattle make cattle embryos excellent models for human. The second part of this research project is therefore aimed at the in vitro culture of bovine embryos beyond the blastocyst stage, initially using protocols (media and substrates) that have been published for extended mouse and human embryo culture. Progress of development will at first instance be analysed by morphology, gene and protein expression.

Requirements

  • You have a Master in Biology or in a related area
  • You have affinity with cell biology and embryology
  • You are intrinsically interested in developmental biology
  • Experience with cell culture is of benefit

Contact person & more information

Bernard Roelen
b.a.j.roelen@uu.nl
www.uu.nl/medewerkers/bajroelen

RESCUE

This project is part of RESCUE, a multidisciplinary, intersectoral and interdisciplinary PhD training programme in Regenerative Medicine and Stem Cells organised by UMC Utrecht (coordinator) and Utrecht University. RESCUE is partly funded by the European Commission under Horizon 2020's Marie Skłodowska-Curie Actions COFUND scheme. There are specific requirements with regards to English language and mobility for candidates who would like to take part in this programme. More information