Life Science Seminar

 

▶ Subject :  Gut Microbiota and the Regulation of Immune Cell Homeostasis

 

▶ Speaker:  Prof. Seung-Woo Lee (IBB, POSTECH)

 

▶ Date :  4:00PM/ May. 11(Fri)/2012

 

▶ Place :  Auditorium(1F), Postech Biotech Center

*Abstract
Commensal microbial communities colonize the barrier surfaces of mammals including the skin, vaginal, and gastrointestinal tracts. In particular, the largest and most diverse microbial communities (collectively, the gut microbiota) reside in the intestine with more than 15,000 individual bacteria species being colonized. These commensal bacteria play roles in shaping immune responses at the intestine as well as at the systemic lymphoid organs. Potentially correlating with this, recent studies have highlighted that the absence or altered composition of commensal bacteria is often connected to many pathological conditions, including diabetes, arthritis, asthma, and inflammatory bowel diseases. Hematopoietic stem cells (HSC) in mouse bone marrow (BM) are located in specialized niches as single cells and are the most well characterized somatic stem cells, often serving as a paradigm for other stem cell types. HSC probably comprise two subsets; a dormant population and a ‘homeostatic’ or ‘activated’ population. In a ‘dormant state’ HSC keep maintaining their quiescence in the G0 stage of the cell cycle, but in a ‘homeostatic state’ HSC are occasionally cycling to regenerate all lineage blood cells. In contrast to the strong feedback signals induced by hematopoietic stress, weaker signals are assumedly derived from small day-to-day changes in blood cell composition, which triggers occasional self-renewal of homeostatic HSC and further differentiate into progenitors. However, the realities of those feedback signals that control HSC homeostasis have been largely unknown. We hypothesize that the weak signals for controlling the homeostasis of HSC in steady state may come from the signals derived from commensal bacteria. In this seminar, I will show the possibility that commensal bacteria can modulate the homeostasis of HSC at BM and discuss potential mechanisms behind.

 

☎ Inquiry : Prof. Lee Yoontae(279-2354)