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Wydooghe E, Vandaele L, Heras S, De Sutter P, Deforce D, Peelman L, De Schauwer C, Van Soom A. Autocrine embryotropins revisited: how do embryos communicate with each other in vitro when cultured in groups? Biol Rev Camb Philos Soc 2015; 92:505-520. [PMID: 26608222 DOI: 10.1111/brv.12241] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 10/15/2015] [Accepted: 10/21/2015] [Indexed: 01/10/2023]
Abstract
In the absence of the maternal genital tract, preimplantation embryos can develop in vitro in culture medium where all communication with the oviduct or uterus is absent. In several mammalian species, it has been observed that embryos cultured in groups thrive better than those cultured singly. Here we argue that group-cultured embryos are able to promote their own development in vitro by the production of autocrine embryotropins that putatively serve as a communication tool. The concept of effective communication implies an origin, a signalling agent, and finally a recipient that is able to decode the message. We illustrate this concept by demonstrating that preimplantation embryos are able to secrete autocrine factors in several ways, including active secretion, passive outflow, or as messengers bound to a molecular vehicle or transported within extracellular vesicles. Likewise, we broaden the traditional view that inter-embryo communication is dictated mainly by growth factors, by discussing a wide range of other biochemical messengers including proteins, lipids, neurotransmitters, saccharides, and microRNAs, all of which can be exchanged among embryos cultured in a group. Finally, we describe how different classes of messenger molecules are decoded by the embryo and influence embryo development by triggering different pathways. When autocrine embryotropins such as insulin-like growth factor-I (IGF-I) or platelet activating factor (PAF) bind to their appropriate receptor, the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway will be activated which is important for embryo survival. On the other hand, the mitogen-activated protein kinase (MAPK) pathway is activated when compounds such as hyaluronic acid and serotonin bind to their respective receptors, thereby acting as growth factors. By activating the peroxisome-proliferator-activated receptor family (PPAR) pathway, lipophilic autocrine factors such as prostaglandins or fatty acids have both survival and anti-apoptotic functions. In conclusion, considering different types of messenger molecules simultaneously will be crucial to understanding more comprehensively how embryos communicate with each other in group-culture systems. This approach will assist in the development of novel media for single-embryo culture.
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Affiliation(s)
- Eline Wydooghe
- Department of Reproduction, Obstetrics, and Herd Health, Faculty of Veterinary Medicine, Ghent University, B-9820, Merelbeke, Belgium
| | - Leen Vandaele
- Animal Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), B-9090, Melle, Belgium
| | - Sonia Heras
- Department of Reproduction, Obstetrics, and Herd Health, Faculty of Veterinary Medicine, Ghent University, B-9820, Merelbeke, Belgium
| | - Petra De Sutter
- Department of Reproductive Medicine, University Hospital, Ghent University, B-9000, Ghent, Belgium
| | - Dieter Deforce
- Laboratory for Pharmaceutical Biotechnology, Ghent University, B-9000, Ghent, Belgium
| | - Luc Peelman
- Laboratory of Animal Genetics, Faculty of Veterinary Medicine, Ghent University, B-9820, Merelbeke, Belgium
| | - Catharina De Schauwer
- Department of Reproduction, Obstetrics, and Herd Health, Faculty of Veterinary Medicine, Ghent University, B-9820, Merelbeke, Belgium
| | - Ann Van Soom
- Department of Reproduction, Obstetrics, and Herd Health, Faculty of Veterinary Medicine, Ghent University, B-9820, Merelbeke, Belgium
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