Chiara Colarusso

IL-1α and IL-1β-producing macrophages populate lung tumor lesions in mice

Macrophages highly populate tumour microenvironment and are referred to as tumor-associated macrophages (TAMs). The inflammasome is a multiprotein complex responsible of IL-1 like cytokines release, which biology has been widely studied by using bone-marrow-derived macrophages to mimic a physiological and/or host defense condition. To understand the role of this complex in lung tumor-associated macrophages (TAMs), we isolated and cultured broncho-alveolar lavage (BAL)-derived cells of lung tumor-bearing mice. The stimulation of lung TAMs with LPS+ATP increased the release of IL-1β. The inhibition of NLRP3 by means of glybenclamide significantly reduced IL-1β release. Similarly, C3H-derived, caspase-1 ko and caspase-11 ko TAMs released significantly reduced levels of IL-1β. Moreover, the stimulation of lung TAMs with the sole LPS induced a significant release of IL-1α, which was significantly reduced after caspase-1 pharmacological inhibition, and in TAMs genetically lacking caspase-1 and caspase-11. The inhibition of calpain I/II by means of MDL28170 did not alter IL-1α release after LPS treatment of lung TAMs. To note, the inoculation of LPS-treated bone marrow-derived macrophages into carcinogen-exposed mice increased lung tumor formation. In contrast, the depletion of TAMs by means of clodronate liposomes reduced lung tumorigenesis, associated to lower in vivo release of IL-1α and IL-1β. In conclusion, our data imply lung tumor lesions are populated by macrophages which pro-tumor activity is regulated by the activation of the NLRP3 inflammasome that leads to the release of IL-1α and IL-1β in a caspase-11/caspase-1-dependent manner.

Role of the inflammasome in chronic obstructive pulmonary disease (COPD)

Inflammation is central to the development of chronic obstructive pulmonary disease (COPD), a pulmonary disorder characterized by chronic bronchitis, chronic airway obstruction, emphysema, associated to progressive and irreversible decline of lung function. Emerging genetic and pharmacological evidence suggests that IL-1-like cytokines are highly detected in the sputum and broncho-alveolar lavage (BAL) of COPD patients, implying the involvement of the multiprotein complex inflammasome. So far, scientific evidence has focused on nucleotide-binding oligomerization domain-like receptors protein 3 (NLRP3) inflammasome, a specialized inflammatory signaling platform that governs the maturation and secretion of IL-1-like cytokines through the regulation of caspase-1-dependent proteolytic processing. Some studies revealed that it is involved during airway inflammation typical of COPD. Based on the influence of cigarette smoke in various respiratory diseases, including COPD, in this view we report its effects in inflammatory and immune responses in COPD mouse models and in human subjects affected by COPD. In sharp contrast to what reported on experimental and clinical studies, randomized clinical trials show that indirect inflammasome inhibitors did not have any beneficial effect in moderate to severe COPD patients.Inflammation is central to the development of chronic obstructive pulmonary disease (COPD), a pulmonary disorder characterized by chronic bronchitis, chronic airway obstruction, emphysema, associated to progressive and irreversible decline of lung function. Emerging genetic and pharmacological evidence suggests that IL-1-like cytokines are highly detected in the sputum and broncho-alveolar lavage (BAL) of COPD patients, implying the involvement of the multiprotein complex inflammasome. So far, scientific evidence has focused on nucleotide-binding oligomerization domain-like receptors protein 3 (NLRP3) inflammasome, a specialized inflammatory signaling platform that governs the maturation and secretion of IL-1-like cytokines through the regulation of caspase-1-dependent proteolytic processing. Some studies revealed that it is involved during airway inflammation typical of COPD. Based on the influence of cigarette smoke in various respiratory diseases, including COPD, in this view we report its effects in inflammatory and immune responses in COPD mouse models and in human subjects affected by COPD. In sharp contrast to what reported on experimental and clinical studies, randomized clinical trials show that indirect inflammasome inhibitors did not have any beneficial effect in moderate to severe COPD patients.

Correction: Circulating and tumor-associated caspase-4: a novel diagnostic and prognostic biomarker for non-small cell lung cancer

[This corrects the article DOI: 10.18632/oncotarget.25049.].

Circulating and tumor-associated caspase-4: A novel diagnostic and prognostic biomarker for non-small cell lung cancer.

Late diagnosis limits therapeutic options and survival rate of non-small cell lung cancer (NSCLC) patients. Therefore the identification of biomarkers represents an emerging medical need. A highly sensitive and specific test was developed to identify/quantify a novel/selective diagnostic biomarker for NSCLC patients, caspase-4. This test was validated by using i) plasma from 125 NSCLC patients and 79 healthy (non-pathological) subjects, ii) plasma from 139 smokers and iii) from 70 chronic-obstructive pulmonary disease (COPD) patients. Caspase-4 quantification was also assessed in the lung tumor mass of 98 paired NSCLC patients compared to 10 non-tumor lung tissues (i.e. tuberculosis). Circulating caspase-4 was detected in both healthy and NSCLC patients; however at different range values: 2.603–3.372 ng/ml for NSCLC patients (95% CI) compared to 0.3994-0.6219 ng/ml for healthy subjects (95% CI). The sensitivity of the test ranged from 97.07% to 100%; the specificity was 88.1% with a positive predictive value of 92.54%, accuracy of 95.19% and AUC of 0.971. Smokers (95% CI, 0.3947–0.6197 ng/ml) and COPD patients (95% CI, 1.703–2.995 ng/ml) showed intermediate values of circulating caspase-4. Tissue levels of caspase-4 in the tumor mass showed that 72 (72.7%) out of 99 patients were positive. More importantly, higher levels (cut-off value = 0.307 ng/ml) of caspase-4 in the tumor mass were associated to reduced overall survival (median 0.92 years) compared to NSCLC patients with lower levels (median 3.02 years). We report for the first time caspase-4 as a novel diagnostic and prognostic biomarker, opening new therapeutic perspectives for NSCLC patients.

Activation of the Absent in Melanoma 2 Inflammasome in Peripheral Blood Mononuclear Cells From Idiopathic Pulmonary Fibrosis Patients Leads to the Release of Pro-Fibrotic Mediators.

Idiopathic pulmonary fibrosis (IPF) is a chronic fibro-proliferative disease characterized by poor prognosis, with a mean survival of ~2–3 years after definite diagnosis. The cause of IPF is still unknown but it is a heterogeneous condition in which the aberrant deposition of extracellular matrix leads to extensive lung remodeling. This remodeling is a consequence of inflammatory responses, but the mechanisms involved are poorly understood. In this study, we first analyzed a bleomycin-induced mouse model, which showed that higher expression of IL-1β, but not IL-18, was correlated to pulmonary cell infiltration and fibrosis. Then, we found that peripheral blood mononuclear cells (PBMCs) from IPF patients released IL-1α and IL-18 in a NLRP3- and calpain-independent manner after LPS ± ATP stimulation. Instead, the activation of the absent in melanoma 2 (AIM2) inflammasome induced the release of IL-1α in a caspase-1-/caspase-8-independent manner; whereas IL-18 release was caspase-1 dependent. These effects correlated with the release of the pro-fibrotic TGF-β, which was induced by AIM2 activation in a caspase-1- and TLR4-independent manner, but dependent on IL-1α. In this context, the activation of AIM2 induced the release of caspase-4 from IPF-derived PBMCs, which correlated with the mRNA levels of this caspase that was higher in IPF than in healthy PBMCs. In conclusion, our findings identify a novel molecular mechanism whereby the activation of AIM2 could lead to the activation of the non-canonical inflammasome (caspase-4 dependent) that induces the release of IL-1α responsible for the release of TGF-β from PBMCs of IPF patients.

Chronic Obstructive Pulmonary Disease-Derived Circulating Cells Release IL-18 and IL-33 under Ultrafine Particulate Matter Exposure in a Caspase-1/8-Independent Manner

Chronic obstructive pulmonary disease (COPD) is considered the fourth-leading causes of death worldwide; COPD is caused by inhalation of noxious indoor and outdoor particles, especially cigarette smoke that represents the first risk factor for this respiratory disorder. To mimic the effects of particulate matter on COPD, we isolated peripheral blood mononuclear cells (PBMCs) and treated them with combustion-generated ultrafine particles (UFPs) obtained from two different fuel mixtures, namely, pure ethylene and a mixture of ethylene and dimethylfuran (the latter mimicking the combustion of biofuels). UFPs were separated in two fractions: (1) sub-10 nm particles, named nano organic carbon (NOC) particles and (2) primarily soot particles of 20–40 nm and their agglomerates (200 nm). We found that both NOC and soot UFPs induced the release of IL-18 and IL-33 from unstable/exacerbated COPD-derived PBMCs. This effect was associated with higher levels of mitochondrial dysfunction and derived reactive oxygen species, which were higher in PBMCs from unstable COPD patients after combustion-generated UFP exposure. Moreover, lower mRNA expression of the repairing enzyme OGG1 was associated with the higher levels of 8-OH-dG compared with non-smoker and smokers. It was interesting that IL-18 and IL-33 release from PBMCs of unstable COPD patients was not NOD-like receptor 3/caspase-1 or caspase-8-dependent, but rather correlated to caspase-4 release. This effect was not evident in stable COPD-derived PBMCs. Our data suggest that combustion-generated UFPs induce the release of caspase-4-dependent inflammasome from PBMCs of COPD patients compared with healthy subjects, shedding new light into the biology of this key complex in COPD.