Regulation of Stem Cells in Their Niche

Abstract

Stem cells are characterized by their ability to asymmetrically divide, generating another self-renewing stem cell and a differentiating daughter cell. They reside within the local niche microenvironment, which, together with systemic signals, regulates intrinsic stem cell function. Stem cells are finely regulated, with even slight deregulation leading to gain of stem cell function and tumorigenesis or loss of stem cell function and tissue degeneration in aging. In this review, we highlight how stem cells are maintained within their niche and what is known about their deregulation in aging. To highlight these points, we look at the Drosophila male germline stem cell niche as a model system, specifically focusing on cell cycle progression, signaling pathways, epigenetics, and the control of spindle orientation by centrosomes. Finally, we sum up pertinent questions to be addressed in understanding stem cell function and their malfunction in aging.