Mast cell chymase-1 and tryptases: therapeutic targets for COPD?
Description:Chronic obstructive pulmonary disease (COPD) is the 3rd leading cause of death worldwide [Citation1–4]. It is characterized by progressive chronic bronchial inflammation that induces small airway remodeling and lung tissue damage in alveoli with emphysema, resulting in severe breathing difficulties [Citation5]. Cigarette smoke (CS) inhalation is the primary cause of this disease. Other causes and risk factors include air pollution, indoor cooking, occupational exposure, and genetics. Patients with COPD patients have increased susceptibility to bacterial and viral infections, causing symptom exacerbation infections [Citation5–9]. There is no cure for COPD, and available treatments only improve the symptoms. This is primarily due to the lack of understanding of the mechanisms involved in COPD pathogenesis. This has been largely due to the absence of short-term mouse models of cigarette smoke-induced COPD that accurately recapitulate the hallmark features of the human disease. Improving our understanding of how COPD develops, progresses and is exacerbated is critical for exploring novel treatments for the disease. Mast cells are a type of innate immune cells that play an important role in the immune system and respond to allergens, pathogens, and foreign particles [Citation10]. These cells are located in connective tissues of the lungs and are involved in the pathogenesis of chronic inflammatory lung diseases, such as COPD. Mast cells can make mediators of their function de novo and contain many granules with pre-formed mediators such as histamines, cytokines, chemokines, and proteases [Citation11]. These granules are released when the mast cells respond to foreign particles and pathogens, in a process termed degranulation [Citation11]. Chymases and tryptases are two of the most important mast cell proteases. Our previous studies showed that their gene expression is increased in the lungs of COPD patients [Citation12,Citation13]. However, the mechanisms underlying the contributions of mast cell proteases in the pathological processes of COPD remain poorly understood. We recently elucidated the roles of mast cell chymases and tryptases in driving chronic inflammation-induced lung damage and emphysema in COPD [Citation12,Citation14–16]. Targeting these molecules may be an effective and urgently needed novel therapeutic option for this debilitating lung disease.









