Intercellular adhesion molecule-1 expression in activated eosinophils is associated with mucosal remodeling in nasal polyps

Exosomes: A Key Piece in Asthmatic Inflammation

Asthma is a chronic disease of the airways that has an important inflammatory component. Multiple cells are implicated in asthma pathogenesis (lymphocytes, eosinophils, mast cells, basophils, neutrophils), releasing a wide variety of cytokines. These cells can exert their inflammatory functions throughout extracellular vesicles (EVs), which are small vesicles released by donor cells into the extracellular microenvironment that can be taken up by recipient cells. Depending on their size, EVs can be classified as microvesicles, exosomes, or apoptotic bodies. EVs are heterogeneous spherical structures secreted by almost all cell types. One of their main functions is to act as transporters of a wide range of molecules, such as proteins, lipids, and microRNAs (miRNAs), which are single-stranded RNAs of approximately 22 nucleotides in length. Therefore, exosomes could influence several physiological and pathological processes, including those involved in asthma. They can be detected in multiple cell types and biofluids, providing a wealth of information about the processes that take account in a pathological scenario. This review thus summarizes the most recent insights concerning the role of exosomes from different sources (several cell populations and biofluids) in one of the most prevalent respiratory diseases, asthma.

Wogonin attenuates nasal polyp formation by inducing eosinophil apoptosis through HIF-1α and survivin suppression

Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) is an inflammatory sinonasal disorder characterized by eosinophilic inflammation and T-helper 2 skewing. Eosinophil accumulation in sinonasal mucosa comprises a major feature of CRSwNP. The study aimed to investigate the effect of the flavone wogonin in nasal polyposis by assessing its ability to induce eosinophil apoptosis in vitro and attenuate eosinophilic CRSwNP in mice. Double immunofluorescence, immunohistochemistry, flow cytometry, and immunoblotting were performed to evaluate hypoxia-inducible factor (HIF)-1α, survivin, and apoptotic markers in the human eosinophilic EoL-1 cell line or sinonasal tissues from patients with CRS with or without NPs. In sinonasal specimens from patients with CRS, HIF-1α and survivin were up-regulated in eosinophils from patients with NPs compared with levels in patients without NPs. Under hypoxia, HIF-1α and survivin expression was up-regulated in EoL-1 cells. Wogonin down-regulated both HIF-1α and survivin in EoL-1 cells. In addition, overexpression of survivin protected EoL-1 cells against apoptosis in response to wogonin. Moreover, wogonin attenuated nasal polyp formation in a murine model. Our findings suggest that wogonin could induce caspase-3 activation by suppressing HIF-1α and survivin expression in EoL-1 cells. Further studies regarding novel therapeutic options for CRSwNP targeting eosinophil apoptosis are needed.