[대학원 생명과학과 세미나 안내]
연사 : 최해웅 교수(고려대학교 생명과학부)
연제 : Benefit and Risk of Inflammation caused by Mast Cells
일시 : 2019년 9월 6일 (금) 오후 5시
장소 : 하나과학관 A동 B131호
초청교수 : 이은진 교수
Abstract
Mast cells had long been considered as causative immune effector cells for allergy and asthma. However, over the last decades, unidentified aspects of mast cells began to be uncovered. This seminar will cover the unique role as host protection as well as unidentified mechanism of anaphylaxis.
Part I. Host protective role of mast cells during the bladder infection.
Uropathogenic E. coli infection at bladder causes massive exfoliation of epithelial cells (ECs), which is considered as an innate immune mechanism to reduce bacterial burden. The shedding of infected ECs was proven to be the result of the recruitment of mast cells directly underneath the superficial epithelium. Chymase, one of the pharmacological active mediators and prepackaged in mast cells granules, caused caspase-1 associated cytolysis and exfoliation of ECs. This explains the protease of ingestible granules causes a form of cell death distinct from those mediated by classical cytotoxic immune cells. Thus, mast cells provide a specific cue to infected epithelial cells for cytolysis and play the role of sentinel cells for protecting the host.
Part II. Mechanism of uncontrolled mast cells' activation during anaphylaxis.
Anaphylactic reactions are a severe form of allergic response. Especially, when allergens enter the bloodstream and circulate the whole body, uncontrolled mast cell activation leads to the systemic discharge of pre-stored proinflammatory mediators. So far, how extravascular mast cells are exposed to blood circulating allergen has not been answered. The existence of a CD301b+ perivascular dendritic cell (DC) subset that continuously samples blood and relays antigens to neighboring MCs, which vigorously degranulate and trigger anaphylaxis. DC antigen transfer involves the active discharge of surface-associated antigens on 0.5- to 1.0-micrometer microvesicles generated by vacuolar protein sorting 4 (VPS4). The newly identified capacity of DCs, which is distributing antigen-bearing MVs to various immune cells in the perivascular space, potentiates inflammatory and immune responses to blood-borne antigens.