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Research significanceAdult stem cells play a key role in tissue homeostasis and damage repair. While many stem cell-supported tissues are affected by changes in diet, age, stress and hormone levels, it is unclear how adult stem cells cooperate with other tissues to ensure appropriate cellular responses to whole-body physiological state. Given the current obesity epidemic and the association between obesity and increased risk for several disease states including type 2 diabetes and cancer, the Armstrong lab is interested in understanding how nutritional sensing by multiple tissues affects adult stem cells.
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Research SummaryPopulations of adult stem cells support several organs in Drosophila melanogaster, including the ovary, gut and testis, making it a powerful model system for addressing how stem cell function is influenced by an organism’s physiology. Two stem cell populations in the Drosophila ovary, germline stem cells (GSCs) and follicle stem cells (FSCs), support oogenesis and respond dramatically to diet. In addition, the fat body acts as a major integrator of nutritional information. Similar to mammalian adipose tissue, the Drosophila fat body has energy storage and endocrine roles. The same highly conserved pathways used by mammals mediate nutrient sensing in the Drosophila ovary and fat body. For example, insulin/insulin-like growth factor and Target of rapamycin (TOR)-mediated signaling control stem cell activity and larval growth in the ovary and fat body, respectively. It is likely that nutrient-sensing pathways in many tissues mediate crosstalk about nutrient status to coordinate the organism’s response to dietary changes, yet the cellular and molecular mechanisms underlying this inter-organ communication remain poorly understood. My postdoctoral studies have shown that distinct nutrient sensing pathways function within adipocytes to regulate various processes along the stem cell lineage in the ovary. Using Drosophila melanogaster, the Armstrong lab takes advantage of genetic, molecular and cell biological tools to understand the mechanisms that underlie the control of adult stem cells by remote nutrient sensing.
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Distinct nutrient sensing pathways in adipocytes elicit specific ovarian response
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Our model system: Drosophila melanogaster
(drawing created by Kate Laws, Ph.D.)
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In addition to the incredible genetic tractability of Drosophila melanogaster (the fruit fly), several features make this organism a powerful model system for addressing how multiple organs coordinate the response of stem cells to nutritional status:
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