Irina Conboy: Making the old feel young again

O riginally from Russia, Irina Conboy joined Susan McCon-nell's laboratory at Stanford University in the early 1990s, where she later pursued her PhD, studying auto-immunity in the laboratory of Patricia Jones. Around the same time she married Michael Conboy, and the two have been scientifi c partners ever since—making a splash in the highly competitive pond of Bay Area stem cell science. Starting with her postdoctoral fellowship with Tom Rando at Stanford, Conboy has dissected what causes muscle stem cells, or satellite cells, to age and lose their capacity for repair and regeneration of muscle tissue. In 2002, she showed that satellite cells use Notch signaling, the same pathway that guides embryonic organogenesis, for activating adult tissue repair (1). She and her husband, also working with Rando as a postdoc, developed novel techniques to tease apart skeletal muscle into single cells called myofi bers in a process which activates satellite cells by mimicking muscle damage in the laboratory dish. This allowed them to study satellite cells and compare the regener-ative capacity of old and young tissue (2). They discovered that old stem cells never actually die out, they just stop responding to injury. If they gave old stem cells an artifi cial boost of Notch activation, they behaved like young stem cells again. From there, Conboy set out to fi nd the root of satellite cell aging. In collaboration with Irv Weissman, she and Michael took a pioneering approach that hooked up the circulation of young mice to old mice. They found that circulating factors from young mice rejuvenated aged stem cells (3). More importantly, in Conboy's mind, they found that old factors negatively infl u-enced repair in young tissues (4). In 2008, as an assistant professor at University of California, Berkeley, Conboy identifi ed at least one of the culprits emanating from aged muscle tissue—an excess of TGF-␤ that shuts down cell cycle progression in satellite cells (5). These fi ndings confi rmed Conboy's unorthodox view of aging. Rather than a lack of the positive infl uences of youth, she sees aging as an excess of negative outputs from aged tissues and the stem cells' microenvironment. In an interview, she explained why old niches should concern anyone designing stem cell–based therapies and what parrots and samurai philosophy have taught her about research. Why did you choose to work with muscle stem cells? I had the idea that perhaps when …