Cigarette smoke-induced iBALT mediates macrophage activation in a B cell-dependent manner in COPD

G John-Schuster, K Hager, TM Conlon… - … of Physiology-Lung …, 2014 - journals.physiology.org
G John-Schuster, K Hager, TM Conlon, M Irmler, J Beckers, O Eickelberg, AÖ Yildirim
American Journal of Physiology-Lung Cellular and Molecular …, 2014journals.physiology.org
Chronic obstructive pulmonary disease (COPD) is characterized by a progressive decline in
lung function, caused by exposure to exogenous particles, mainly cigarette smoke (CS).
COPD is initiated and perpetuated by an abnormal CS-induced inflammatory response of
the lungs, involving both innate and adaptive immunity. Specifically, B cells organized in
iBALT structures and macrophages accumulate in the lungs and contribute to CS-induced
emphysema, but the mechanisms thereof remain unclear. Here, we demonstrate that B cell …
Chronic obstructive pulmonary disease (COPD) is characterized by a progressive decline in lung function, caused by exposure to exogenous particles, mainly cigarette smoke (CS). COPD is initiated and perpetuated by an abnormal CS-induced inflammatory response of the lungs, involving both innate and adaptive immunity. Specifically, B cells organized in iBALT structures and macrophages accumulate in the lungs and contribute to CS-induced emphysema, but the mechanisms thereof remain unclear. Here, we demonstrate that B cell-deficient mice are significantly protected against CS-induced emphysema. Chronic CS exposure led to an increased size and number of iBALT structures, and increased lung compliance and mean linear chord length in wild-type (WT) but not in B cell-deficient mice. The increased accumulation of lung resident macrophages around iBALT and in emphysematous alveolar areas in CS-exposed WT mice coincided with upregulated MMP12 expression. In vitro coculture experiments using B cells and macrophages demonstrated that B cell-derived IL-10 drives macrophage activation and MMP12 upregulation, which could be inhibited by an anti-IL-10 antibody. In summary, B cell function in iBALT formation seems necessary for macrophage activation and tissue destruction in CS-induced emphysema and possibly provides a new target for therapeutic intervention in COPD.
American Physiological Society