Junying Yuan (Chinese: 袁钧瑛; pinyin: Yuán Jūnyīng, born October 3, 1958) is the Elizabeth D. Hay Professor of Cell Biology at Harvard Medical School,[1] best known for her work in cell death. Early in her career, she contributed significant findings to the discovery and characterization of apoptosis.[2][3] More recently, she was responsible for the discovery of the programmed form of necrotic cell death known as necroptosis.[4]
In the United States, she completed her Ph.D. in Neuroscience(1989) at Harvard University under the supervision of MIT professor H. Robert Horvitz, where she endeavored to elucidate the molecular mechanisms behind programmed cell death in the nematodeCaenorhabditis elegans. She identified the proteins ced-3 and ced-4 as drivers behind programmed cell death in C. elegans, and subsequently identified the mammalian homologue of ced-3 known as interleukin-1 beta-converting enzyme(ICE), later called caspase-1.[2][3][6]
Career
Junying Yuan established an independent lab at Harvard-affiliated Massachusetts General Hospital in 1989, immediately upon completion of her Ph.D. [5] Her initial efforts were directed towards providing evidence for the functional role of caspases in mediating mammalianapoptosis.[7][8] Her independent work at this stage provided the first insights into molecular mechanisms in mammalian apoptosis, which contributed significantly to the Nobel Prize in Chemistry won by her Ph.D. supervisor, Robert Horvitz.[9]
In 1996, Yuan moved her lab to the Department of Cell Biology at Harvard Medical School's Longwood campus, where she continued her investigation into cell death. Her work delved further into programmed cell death and revealed a wide cohort of proteins involved in the regulation and consequences of apoptosis. Some notable work includes her discovery that BID cleavage by caspase-8 mediates mitochondrial damage in apoptosis,[10] and her discovery of caspase-11's role in regulating caspase-1-driven inflammation.[11]
In 2005, Yuan's group discovered a non-apoptotic form of programmed necrotic cell death, which they termed "necroptosis".[4] Other groups first observed that the stimulation of Fas/TNFR family of death-domain receptors (DR) activated a canonical apoptotic pathway; however, in many cell types, not only did caspase inhibition fail to inhibit cell death, as would be expected of canonical apoptosis, but stimulated cells experienced a form of cell death that more closely resembled necrosis than apoptosis.[12] Yuan's group conducted a chemical screen that identified a small molecule capable of inhibiting DR-driven cell death, necrostatin-1, and demonstrated necroptosis' role in ischemic neuronal injury, thereby positing a potential role for necrostatin-1 in stroke treatment. Her group then identified RIPK1 as the target for necrostatin-1,[13] thus implicating it as a key player in necroptosis.
Yuan went on to identify and characterize members of the signaling network responsible for regulating necroptosis,[14] and continues to elucidate the mechanisms of necroptosis while exploring its potential as a target of therapeutic intervention. Necrosis was previously considered to be a form of passive cell death, forced in response to stress. This belief had driven an aversion towards developing therapeutic applications targeting necrosis. In demonstrating a form of programmed necrosis, Yuan's work revealed new avenues of treatment for an ever-increasing cohort of diseases where necroptosis is implicated.[15] As of 2019[update], small-molecule inhibitors of RIPK1 have advanced beyond Phase I human clinical trials for the treatment of various inflammatory and neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease, rheumatoid arthritis, psoriasis, and Crohn's disease.[16]
^ abYuan, J. Y.; Horvitz, H. R. (1990). "The Caenorhabditis elegans genes ced-3 and ced-4 act cell autonomously to cause programmed cell death". Developmental Biology. 138 (1): 33–41. doi:10.1016/0012-1606(90)90174-h. PMID2307287.
^ abYuan, J; Horvitz, H. R. (1992). "The Caenorhabditis elegans cell death gene ced-4 encodes a novel protein and is expressed during the period of extensive programmed cell death". Development. 116 (2): 309–20. doi:10.1242/dev.116.2.309. PMID1286611.
^ abDegterev, A; Huang, Z; Boyce, M; Li, Y; Jagtap, P; Mizushima, N; Cuny, G. D.; Mitchison, T. J.; Moskowitz, M. A.; Yuan, J (2005). "Chemical inhibitor of nonapoptotic cell death with therapeutic potential for ischemic brain injury". Nature Chemical Biology. 1 (2): 112–9. doi:10.1038/nchembio711. PMID16408008. S2CID866321.
