PhD, Yale University School of Medicine, 1995
MPhil, Yale University School of Medicine, 1993
Nutrient availability has well documented effects on tissue stem cell lineages in a wide range of multicellular organisms; yet, the molecular, cellular and physiological mechanisms underpinning stem cell control by diet, metabolism or hormones in vivo remains largely unexplored. Dr. Drummond-Barbosa pioneered using Drosophila melanogaster as a model to study adult stem cell regulation by diet, and her laboratory identified several mechanisms that link diet to stem cell proliferation and self-renewal, as well as differentiation and survival of their progeny. They demonstrated that insulin-like peptides directly modulate germline stem cell (GSC) proliferation, and act on cap cells, major niche components, to control GSC maintenance. They showed that the nutrient sensor Target of Rapamycin (TOR) and the energy sensor AMP-dependent kinase have surprisingly specific roles in the GSC and follicle stem cell lineages, and that the steroid ecdysone stimulates GSC responsiveness to niche signals. Other groups subsequently showed that diet-dependent pathways regulate Drosophila male GSCs, intestinal stem cells, and hematopoietic stem cells, and that similar pathways also modulate mammalian stem cell lineages, underscoring the wide relevance of our studies.
More recently, Dr. Drummond-Barbosa’s research program has been addressing the link between adipocyte physiology and stem cell biology. This question is particularly relevant to the current obesity epidemic and to the poorly understood connection between obesity and cancers. Using a combination of genetic tools that allow us to manipulate gene function exclusively in adipocytes, they showed that amino acid sensing by adult adipocytes has highly specific effects on the GSC lineage in the Drosophila ovary: (1) low amino acid levels trigger the evolutionarily conserved amino acid response pathway through unloaded tRNA-mediated activation of the GCN2 kinase within adipocytes to remotely control GSC numbers in the ovary; and (2) amino acids modulate TOR signaling within adipocytes to modulate the efficiency of oocyte ovulation. In a separate study, they also showed that adiponectin signaling (which in mammals is stimulated by the adipocyte proteohormone adiponectin) is required for Drosophila GSC maintenance. Ongoing/future efforts of the Drummond-Barbosa research group aim at identifying new systemic mediators of diet, with special emphasis on adipocyte- and neural-derived factors.
Honors and Awards
1988 - First place in college entrance exam for Biological Sciences, Universidade Federal de Minas Gerais (Brazil)
1990-1991 - Scientific Initiation Fellowship, Conselho Nacional de Pesquisas (Brazil)
1993-1995 - Miles Scholar Award, Bayer Corporation
1997-2000 - National Research Service Award, National Institutes of Health
2006 - Chancellor’s Award for Research, Vanderbilt University
2008 - Semifinalist, 2009 Early Career Scientist Competition, Howard Hughes Medical Institute
2009 - Invited Plenary Lecture, 50th Annual Drosophila Research Conference, Chicago, IL
2007-2011 - American Cancer Society Research Scholar
2014 - Elected as a fellow of the American Association for the Advancement of Science (AAAS)