Asymmetric division of adult stem cells that produces a self-renewing stem cell and a differentiating daughter cell is crucial for tissue homeostasis in diverse systems. Disruption of this balance is postulated to underlie many pathological conditions, including tumorigenesis/tissue hyperplasia (due to excess self-renewal) and tissue degeneration/aging (due to excess differentiation). Intensive investigations have revealed the mechanisms that polarize cells and orient the division plane to achieve asymmetric cell division; however, less is known about how cells might respond to perturbation of cell polarity and whether/how cells might correct such perturbation prior to cell division to ensure the asymmetric outcome of the division. Also, it has been speculated that the stem cell niche might regulate asymmetric stem cell division, in addition to its well-established role in specifying stem cell identity. However, due to the essential requirement of the stem cell niche in stem cell maintenance, the role of the niche in directing oriented, asymmetric stem cell division has never been directly tested. In this proposal, we aim to investigate the role of the stem cell niche in instructing oriented stem cell division, and the additional layer of the mechanism (the centrosome orientation checkpoint; COC) that further ensures asymmetric stem cell division using Drosophila male germline stem cells (GSCs) as a model system. Our preliminary study suggests two novel critical mechanisms that orient GSC spindles leading to asymmetric stem cell division. 1) The niche-derived self-renewal factor (Upd) regulates spindle orientation by directing the receptor-microtubule interaction, in addition to its well-known role as a self-renewa factor. 2) Bazooka/Par-3 forms a small subcellular structure, providing a docking site for the centrosomes to achieve the correct orientation, and such docking likely serves as a condition that satisfies the checkpoint that monitors the correct centrosome orientation. Successful completion of this proposal will reveal novel mechanisms for the asymmetric stem cell division and its checkpoint, contributing to our understanding of stem cell-mediated tissue homeostasis.

Public Health Relevance

This proposal aims to investigate 1) the role of stem cell niche in the spindle orientation of stem cells and 2) a novel checkpoint mechanism that ensures correct spindle orientation in stem cells. The results will provide fundamental knowledge on how asymmetric stem cell division is regulated to maintain tissue homeostasis.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM118308-03
Application #
9458212
Study Section
Development - 1 Study Section (DEV1)
Program Officer
Salazar, Desiree Lynn
Project Start
2016-04-06
Project End
2020-03-31
Budget Start
2018-04-01
Budget End
2019-03-31
Support Year
3
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Venkei, Zsolt G; Yamashita, Yukiko M (2018) Emerging mechanisms of asymmetric stem cell division. J Cell Biol 217:3785-3795
Chen, Cuie; Cummings, Ryan; Mordovanakis, Aghapi et al. (2018) Cytokine receptor-Eb1 interaction couples cell polarity and fate during asymmetric cell division. Elife 7:
Yamashita, Yukiko M (2018) Subcellular Specialization and Organelle Behavior in Germ Cells. Genetics 208:19-51
Lu, Kevin; Jensen, Lindy; Lei, Lei et al. (2017) Stay Connected: A Germ Cell Strategy. Trends Genet 33:971-978
Inaba, Mayu; Yamashita, Yukiko M (2017) Evaluation of the Asymmetric Division of Drosophila Male Germline Stem Cells. Methods Mol Biol 1463:49-62
Chen, Cuie; Fingerhut, Jaclyn M; Yamashita, Yukiko M (2016) The ins(ide) and outs(ide) of asymmetric stem cell division. Curr Opin Cell Biol 43:1-6
Inaba, Mayu; Yamashita, Yukiko M; Buszczak, Michael (2016) Keeping stem cells under control: New insights into the mechanisms that limit niche-stem cell signaling within the reproductive system. Mol Reprod Dev 83:675-83
Chen, Cuie; Inaba, Mayu; Venkei, Zsolt G et al. (2016) Klp10A, a stem cell centrosome-enriched kinesin, balances asymmetries in Drosophila male germline stem cell division. Elife 5: