Part 1. Enhanced Th2 cell differentiation and function in the absence of Nox2 in allergic disease
Chronic granulomatous disease (CGD) inherits abnormal function of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (Nox2). Nox2 originally identified in phagocytes is responsible for the production of reactive oxygen species (ROS) that kill engulfed pathogens. Thus, CGD patients are susceptible to infections by bacteria and fungi and also suffer from persistent inflammatory responses in liver, kidney, colon and lung. There have been studies to reveal the function of Nox2 in hyper-inflammatory diseases, especially in asthma, but the exact role of Nox2 in asthma is still unclear and controversial. To determine whether Nox2 deficiency affects allergic lung inflammation, we utilized various experimental asthma models to clarify the recent debates. Furthermore, we attempted to reveal the precise mechanism of Nox2 deficiency in a T cell intrinsic manner by using in vitro activation. Asthma phenotypes were analyzed in response to various allergen-induced experimental asthma. To understand the underlying mechanisms of exaggerated Th2 effector functions, we investigated the degree of T cell activation, levels of activation induced cell death (AICD), and regulatory T (Treg) cell differentiation in Nox2-deficient T cells. All experimental asthma phenotypes including airway hyper-responsiveness, lung inflammation with eosino- philia, and mucus production were increased through enhanced Th2 differentiation in Nox2- null mice. Nox2-deficient T cells also showed hyper-activation, reduced AICD, and diminished Treg cell differentiation through increased AKT phosphorylation and enhanced mito- chondrial ROS production. Our findings indicate that Nox2 deficiency results in exaggerated experimental asthma, which is caused by enhanced Th2 effector function in a T cell intrinsic manner.
Part 2. Innate type 2 immunity is associated with eosinophilic pleural effusion in pri- mary spontaneous pneumothorax
Eosinophilic pleural effusion (EPE) is characterized by greater than 10% eosinophilia and is frequently associated with air and/or blood in the pleural cavity. Primary spontaneous pneumothorax (PSP), defined as the spontaneous presence of air in the pleural space, is one of the most common causes of EPE. Recent studies have shown that type 2 immune responses play important roles in eosinophilic airway inflammation resulting in pleural pathology. However, the exact predominant mediator that induce type 2 immunity, resulting in EPE with PSP in humans, remains unclear. Thus, we examined whether T helper 2 (Th2) cells, IL-33, thymic stromal lymphopoietin (TSLP) or type 2 innate lymphoid cells (ILC2) are associated factors. First, eosinophil-associated cytokines were measured in the pleural fluid of patients with PSP and control subjects. Second, Th2 cell and ILC2 responses in the pleural cavity and peripheral blood were also evaluated by in vitro re-stimulation and intracellular cytokine staining of T cells and ILC2s in patients with PSP and control subjects. Third, innate type 2 cytokines such as IL-33 and TSLP levels were measured. Lastly, IL-33-mediated IL-5 pro- duction by ILC2 was also evaluated. As a result, significantly higher concentrations of IL-5 and eotaxin-3 were detected in the pleural fluid of patients with PSP, in addition to signifi- cantly higher concentrations of IL-33 and TSLP. Although IL-5 production was induced by IL-33 treatment of ILC2s, other Th2 cell-mediated immune responses were not detected. Based on these results, we concluded that innate immune responses characterized by the pro- duction of IL-33, TSLP, and IL-5 are associated with the development of EPE in PSP by an ILC2-dependent and Th2-independent mechanism.
Part 1. 과민성 염증질환에서 NADPH (Nicotinamide adenine dinucleotide phosphate) 산화효소 2 결핍에 의해 증가된 2 형 도움 T 세포의 분화와 기능 증진
만성 육아종 (Chronic granulomatous disease) 환자는 NADPH 산화요소 2 의 유전적 결핍을 자기고 있으며 박테리아와 곰팡이에 의한 감염 외에도 과민성 폐 및 기도염증을 호소한다고 알려져 있다. 하지만, NADPH 산화효소 2 결핍 쥐를 이용한 천식에 관한 기존의 연구는 결과가 상이하고 그 기전이 분명하지 않다. 본 연구에서, 다양한 알러젠과 천식유도 방법을 이용한 결과 NADPH 산화효소 2 결핍 쥐에서 증가된 기도 및 폐 염증이 일어나는 것을 확인할 수 있었다. 또한 NADPH 산화효소 2 결핍에 의해 증가된 2 형 도움 T 세포의 분화와 활성이 심한 천식증상의 원인이라는 것을 확인하였다. 그 기전으로는 증가된 AKT (트레오닌308/세린 473)의 인산화와 미토콘드리아에 의한 활성산소 생산 증가라는 것을 밝혔으며 이것이 자극 유도성 세포사멸 (AICD)의 감소와 조절 T 세포로 분화감소로 이어진다는 것을 확인하였다. 마지막으로, 미토콘드리아 활성산소의 억제를 통해 기도 및 폐 염증의 완화와 2 형 도움 T 세포의 분화를 억제할 수 있다는 것을 증명하였다.
Part 2. 호산구 증가성 원발성 기흉환자에서 2 형 선천면역의 연구
원발성 기흉은 원인 질환 없이 발생하며 폐포 내 공기가 흉강 내로 누출되면서 폐 허탈을 초래하는 질환으로 흉강 내에 호산구가 증가되어 있는 면역학적 특징을 가진다. 본 연구에서, 2 형 선천 림프구가 분비하는 인터류킨-5 에 의한 호산구의 증가를 보고하였다. 2 형 선천림프구는 상피세포에서 분비하는 인터류킨-33, TSLP (thymic stromal lymphopoietin)의 분비에 의해서 활성화되어 인터류킨-5,13 을 분비하는 것을 확인하였다. 또한 호산구 증가에 중요한 역할을 한다고 알려진 2 형 도움 T 세포는 관련이 없다는 것을 확인하였다. 본 연구는 최초로 환자 흉수액 내에서 2 형 선천 림프구의 존재와 역할을 확인하였고 호산구 증가의 원인을 밝힘으로써 원발성 기흉의 치료와 예후관찰에 큰 도움이 될 것이다.
