Research in my laboratory focuses on 1) Identification of genes and gene regulatory molecules associated with oocyte maturation and early embryo development with special emphasis on bovine, 2) investigating the role of extracellular vesicle coupled miRNAs and proteins in oocyte and embryo development and 3) Functional analysis of genes and regulatory miRNAs in various reproductive cells, oocytes and preimplantation embryos. My lab investigates the molecular mechanisms regulating female fertility in cattle with special emphasis on gene and gene regulatory mechanisms associated with oocyte maturation and preimplantation embryo development. Embryos response to various culture conditions (in vitro or in vivo) or environmental stressors with respect to transcriptome and epigenome modulation was the focus of my research in the last decade. Recent researches in my lab focuses on understanding the mechanisms behind embryos survival under suboptimal environmental conditions. The most significant contribution of my research in the last years is the identification of the NRF2-mediated oxidative stress response as a dominant pathway playing a role in the survival of bovine embryos under suboptimal or harmful conditions. Presently, we are using various genetic and pharmacological approaches to modulate the NRF2-mediated oxidative stress response in preimplantation embryos. For this we use state-of-the-art CRISPR-cas9 and siRNA to knockdown the KEAP1 gene, which is the cytoplasmic inhibitor of NRF2 in bovine oocytes and embryos to increase the availability of NRF2 protein and subsequent transcription of antioxidant enzymes. Moreover, various compounds with antioxidant capacity will be utilized to enhance the survival of preimplantation embryos under various suboptimal conditions. The research results from my lab are expected to contribute to the development of molecular markers for oocyte and embryo developmental competence and improving embryos survival in Assisted Reproductive Technology (ART) procedures in cattle with potential translation to humans.
Ph.D., University of Bonn, Germany, 2004M.Sc, University of Bonn, Germany, 2000B.Sc., Haramaya University of Agriculture, Ethiopia, 1990
Menjivar N, Gad A, Thompson RE, Meyers MA, Hollinshead FK, Tesfaye D. (2023): Bovine oviductal organoids: a multi-omics approach to capture the cellular and extracellular molecular response of the oviduct to heat stress. BMC Genomics 24, 646. Ahmed Gad, Kamryn Joyce, Nico Graham Menjivar, Daniella Heredia, Camila Santos Rojas, Dawit Tesfaye, Angela Gonella-Diaza 2023. Extracellular vesicle-microRNAs mediated response of bovine ovaries to seasonal environmental changes. J Ovarian Res 16, 101. https://doi.org/10.1186/s13048-023-01181-7Menjivar NG, Gad A, Gebremedhn S, Ghosh S, Tesfaye D. 2023. Granulosa cell-derived extracellular vesicles mitigate the detrimental impact of thermal stress on bovine oocytes and embryos. Front Cell Dev Biol. Apr 6; 11:1142629. doi: 10.3389/fcell.2023.1142629.Jessica Kurzella, Dennis Miskel, Franca Rings, Ernst Tholen, Dawit Tesfaye, Karl Schellander, Dessie Salilew-Wondim, Eva Held-Hoelker, Christine Große-Brinkhaus, Michael Hoelker: (2023): Mitochondrial bioenergetic profiles of warmed bovine blastocysts are typically altered after cryopreservation by slow freezing and vitrification. Theriogenology 214, 21-32.Rabaglino MB, Salilew-Wondim D, Zolini A, Tesfaye D, Hoelker M, Lonergan P, Hansen PJ. 2023. Machine-learning methods applied to integrated transcriptomic data from bovine blastocysts and elongating conceptuses to identify genes predictive of embryonic competence. FASEB J. 37(3)Gebremedhn S, Gad A, Ishak GM, Menjivar NG, Gastal MO, Feugang JM, Prochazka R, Tesfaye D, Gastal EL. 2023 Dynamics of extracellular vesicle-coupled microRNAs in equine follicular fluid associated with follicle selection and ovulation. Molecular Human Reproduction 29, 4 Sohel MMH, Hoelker M, Schellander K, Tesfaye D. 2022. The extent of the abundance of exosomal and non-exosomal extracellular miRNAs in the bovine follicular fluid. Reprod Domest Anim. 57(10): 1208. Mikhael Poirier, Dawit Tesfaye, Tsige Hailay, Dessie Salilew-Wondim, Samuel Gebremedhn, Franca Rings, Christiane Neuhof, Karl Schellander & Michael Hoelker (2020): Metabolism-associated genome-wide epigenetic changes in bovine oocytes during early lactation. Nature Scientific Reports. 10:2345 Omar Khadrawy, Samuel Gebremedhn, Dessie Salilew-Wondim, Franca Rings, Christiane Neuhoff, Michael Hoelker, Karl Schellander, Dawit Tesfaye (2020): Quercetin supports bovine preimplantation embryo development under oxidative stress condition via activation of the Nrf2 signaling pathway. Reproduction in Domestic Animals. In press.Dawit Tesfaye, Tsige Hailay, Dessie Salilew-wondim, Michael hoelker, Simret Bitseha, Samuel Gebremedhn (2020): Extracellular vesicle mediated molecular signaling in ovarian follcile: Implication for oocyte developmental competence. Theriogenology, 150:70-74.
Reproductive Biology- Molecular regulation of early embryo development