About Dawit
Research in my laboratory centers on understanding the molecular mechanisms that regulate oocyte maturation and early embryo development, with a particular emphasis on bovine models. Our work is organized around three main themes: 1.) Idenitification of genes and gene regulatory molecules involved in oocyte maturation and early embryogenesis; 2.) Investigation of the role of extracellular vesicle (EV)-associated microRNAs and proteins in oocyte and embryo development; and 3.) Functional analysis of genes and regulatory miRNAs in reproductive cells, including oocytes and preimplantation embryos.
Over the past decade, my research has also examined how embryos respond to various culture environments (in vitro or in vivo) and environmental stressors, with a focus on transcript and epigenomic modulation. Currently, my lab is exploring the mechanisms that support embryo survival under suboptimal environmental conditions. To this end, we employ cutting-edge tools such as CRISPR-Cas9 and siRNA-mediated knockdown of the KEAP1 gene - the cytoplasmic inhibitor of NRF2 - in bovine oocytes and embryos. This approach aims to enhance NRF2 availability and promote the transcription of antioxidant enzymes critical for cellular protection.
Another active research area in the lab investigates EV-mediated molecular signaling in bovine follicular cells, oocytes, and preimplantation embryos, particularly in the context of development and stress response modulation. A major focus at the Animal Reproduction and Biotechnology Laboratory (ARBL) is the development of a 3D organoid culture system to model bovine embryo-oviduct interactions in vitro, enabling us to study the role of EVs in embryo-maternal communication.
Findings from this research are expected to contribute to the idenitification of molecular markers of oocyte and embryo competence, as well as strategies to enhance embryo survival in assisted reproductive technologies (ART) in cattle - with potential applications in human reproductive medicine.
Education
Ph.D., University of Bonn, Germany, 2004M.Sc, University of Bonn, Germany, 2000B.Sc., Haramaya University of Agriculture, Ethiopia, 1990
Publications
Heather M Rogers, Ahmed Gad, Gentry K Cork, Nico G Menjivar, William B Schoolcraft, Dawit Tesfaye, Ye Yuan (2025): Age-related integrative transcriptomic profiling of human granulosa cells reveals mRNA-microRNA regulatory network associated with key ovulation dynamics, Biology of Reproduction, 2025;, ioaf034, https://doi.org/10.1093/biolre/ioaf034Dessie Salilew-Wondim, Ernst Tholen, Christine Große-Brinkhaus, Eva Held-Hoelker, Dennis Miskel, Franca Rings, Karl Schellander, Urban Besenfelder, Vitezslav Havlicek, Dawit Tesfaye & Michael Hoelker (2025): Sexually dimorphic gene expression responses of bovine embryos to the maternal microenvironment on day 13 of gestation. BMC Genomics 26, 372. https://doi.org/10.1186/s12864-025-11570-5Eva Held-Hoelker, Lientje Sophie Haake, Jessica Kurzella, Maibritt Schreiber, Christina Dauben, Dessie Salilew-Wondim, Nasser Ghanem, Franca Rings, Christine Große-Brinkhaus, Ernst Tholen, Dawit Tesfaye, Michael Hoelker (2025). Heat stress during maturation of bovine oocytes profoundly impacts the mitochondrial bioenergetic profile and causes endoplasmic reticulum stress in subsequent blastocysts, Biology of Reproduction, ioaf070, https://doi.org/10.1093/biolre/ioaf070Menjivar 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.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 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.
Research Specialty
Reproductive Biology- Molecular regulation of early embryo development