【29th.Sept.】Stem Cell Development: Tales of Two Niches
日期：2016-09-29
阅读：783
TOPIC：Stem Cell Development: Tales of Two Niches
SPEAKER： Prof. Dr. Ting Xie, Stowers Institute for Medical Research, USA
TIME： Sept. 29 (Thursday)）PM14:00
VENUE： Room 526, Chemistry Building A (化学A楼526会议室)
INVITER： Prof. Deyue Yan (颜德岳教授), Prof. Xinyuan Zhu (朱新远教授)
Abstract: between self-renewal and differentiation. Drosophila ovarian germline stem cells (GSCs) are an effective system for studying self-renewal and differentiation at the molecular and cellular level because of powerful genetics and exceptional cell biology. Our studies have revealed how extrinsic niche signals and intrinsic factors to work cooperatively to control both GSC self-renewal and differentiation. Almost two decades ago, we demonstrate that GSC self-renewal regulated by the niche, which consistent of cap cells. This has been proven to be a general mechanism for adult mammalian stem cells. The self-renewal niche uses BMP signaling to control GSC self-renewal, and E-cadherin for niche anchorage and thus long-term self-renewal. We have also revealed that the niche works with intrinsic factors to promote self-renewal by preventing differentiation. In order for GSC progeny to differentiate properly, self-renewal-promoting protein complexes are effectively inactivated or converted into differentiation-promoting complexes via protein competition. Although stem cell lineage differentiation has been thought as a “developmental default state”, we have recently demonstrated that escort cells form a distinct niche to promote GSC progeny differentiation extrinsically. This niche is named as the differentiation niche. The experimental evidence for the existence of the differentiation niche in mammalian system has begun to emerge so the differentiation niche likely represents a general mechanism for adult mammalian stem cells. Genetic studies have identified various classes of the genes that function in the differentiation niche to promote GSC progeny differentiation. Mechanistically, the differentiation niche promotes GSC progeny differentiation indirectly by preventing BMP signaling and also directly by sending instructive signals. Therefore, stem cell lineage development is controlled by the concerted actions of niche signals and intrinsic factors
Short Biography: Dr. Ting Xie obtained his PhD in Molecular Biology and Biochemistry from Rutgers University. Currently, He is a full investigator at Stowers Institute for Medical Research and a professor in University of Kansas Medical Center. His main research area is stem cell biology. He is one of the leaders and pioneers in studying the stem cell niche and its mechanisms controlling self-renewal. Dr. Xie was among the first to experimentally demonstrate the existence of the stem cell niche. Recently, he has also proposed a distinct niche known as the differentiation niche for controlling stem cell lineage differentiation. His laboratory has elucidated how the two niches work together to control stem cell development and thus tissue regeneration. Dr. Xie‘s laboratory uses Drosophila ovarian germline stem cells as a model system to elucidate the structures and functions of the self-renewal niche and the differentiation niche as well as the molecular and cellular mechanisms underlying self-renewal, differentiation, stem cell competition and aging. Additionally, his lab has demonstrated the roles of various signaling pathways (BMP, Hh, Wnt and Notch), cadherin-mediated cell adhesion, epigenetic factors, non-coding RNAs and various protein complexes (COP9, CCR4-NOT and eIF4) in the regulation of self-renewal and differentiation. Recently, his lab has begun the exploration of stem cell application in treating retinal degenerating diseases. Dr. Xie received Hudson Award in 2003, and has been serving on the scientific advisory board of The Glaucoma Foundation and on the editorial board of Cell Research, Development and eight other scientific journals.
