Exposure of cigarette smoke condensate activates NLRP3 inflammasome in vitro and in vivo: A connotation of innate immunity and atherosclerosis

Machine learning models for predicting the risk factor of carotid plaque in cardiovascular disease

Introduction

Cardiovascular disease (CVD) is a group of diseases involving the heart or blood vessels and represents a leading cause of death and disability worldwide. Carotid plaque is an important risk factor for CVD that can reflect the severity of atherosclerosis. Accordingly, developing a prediction model for carotid plaque formation is essential to assist in the early prevention and management of CVD.

Methods

In this study, eight machine learning algorithms were established, and their performance in predicting carotid plaque risk was compared. Physical examination data were collected from 4,659 patients and used for model training and validation. The eight predictive models based on machine learning algorithms were optimized using the above dataset and 10-fold cross-validation. The Shapley Additive Explanations (SHAP) tool was used to compute and visualize feature importance. Then, the performance of the models was evaluated according to the area under the receiver operating characteristic curve (AUC), feature importance, accuracy and specificity.

Results

The experimental results indicated that the XGBoost algorithm outperformed the other machine learning algorithms, with an AUC, accuracy and specificity of 0.808, 0.749 and 0.762, respectively. Moreover, age, smoke, alcohol drink and BMI were the top four predictors of carotid plaque formation. It is feasible to predict carotid plaque risk using machine learning algorithms.

Conclusions

This study indicates that our models can be applied to routine chronic disease management procedures to enable more preemptive, broad-based screening for carotid plaque and improve the prognosis of CVD patients.

Effect of cannabis smoke condensate on human nasal epithelial cell adhesion, growth, and migration

OBJECTIVE

When inhaled, cannabis smoke interacts with airway tissues, including the nasal mucosa, which may lead to nasal pathologies. We examined the effect of cannabis smoke condensate (CSC) on nasal epithelial cell and tissue behaviors.

METHODS

Human nasal epithelial cells were exposed or not to CSC at different concentrations (1, 5, 10, and 20 %) and for different durations. Cell adhesion and viability were assessed, as well as post-wound cell migration and lactate dehydrogenase (LDH) release.

RESULTS

The nasal epithelial cells showed a larger cell size and a faint nucleus following exposure to CSC, compared to that observed in that control. This was supported by fewer adherent cells present after exposure for either 1 or 24 h to 5, 15, and 20 % CSC. CSC also had a significant toxic effect by reducing cell viability after both 1 and 24 h of exposure. This toxic effect was significant even at a low concentration (1 %) of CSC. The effects on nasal epithelial cell viability were confirmed by the decrease in cell migration. After the scratch and subsequent exposure to CSC for either 6 or 24 h, a complete inhibition of nasal epithelial cell migration was observed, compared to that found in the controls. CSC was toxic to the nasal epithelial cells, as the level of LDH significantly increased following cell exposure all CSC concentrations.

CONCLUSION

Cannabis smoke condensate had a negative effect on several nasal epithelial cell behaviors. These findings indicate that cannabis smoke could be a threat to nasal tissues and ultimately lead to nasal and sinus disorders.

The NLRP3 Genetic Variant (rs10754555) Reduces the Risk of Adverse Outcome in Middle-Aged Patients with Chronic Coronary Syndrome

Background

Inflammation is central in development of cardiovascular disease (CVD). Aberrant function of the Nod-Like Receptor Protein 3 (NLRP3) inflammasome, a central mediator in the proinflammatory response, has been associated with atherosclerosis. The influence of genetic determinants on this inflammatory pathway and its downstream effects is less known. We aimed to investigate the frequency of a single NLRP3 gene variant according to clinical outcome in CVD and its influence on NLRP3-related markers.

Methods

In this observational study, we included 1001 patients with chronic coronary syndrome. Blood samples were drawn at inclusion, including whole-blood and PAXgene tubes for DNA and RNA isolation, respectively. Allelic discrimination of the NLRP3 single nucleotide polymorphism rs10754555 was performed; and gene expression of NLRP3, Toll-Like Receptor 4, Interleukin- (IL-) 1β, and IL-18 was relatively quantified, both methods by RT-PCR. Circulating IL-6, high-sensitivity (hs) C-reactive protein, IL-18, and IL-12 were measured by enzyme-like immunosorbent assays. Clinical endpoints during 2 years (n = 106) were a composite of unstable angina pectoris, myocardial infarction, nonhemorrhagic stroke, and death.

Results

Minor allele frequency of the NLRP3 variant was 0.36. In all, no association of the NLRP3 variant with clinical subgroups or outcome was found, neither any significant influence on the genes' mRNA expression or circulating protein. However, in subjects < 56 years (25 percentile), the variant G-allele is associated with significant lower risk of suffering a composite event (OR = 0.43 (95% CI 0.19, 0.97), p = 0.043, adjusted). In the same age group, the NLRP3 gene was accordingly downregulated in G-allele carriers vs. noncarriers, and circulating IL12 was significantly reduced (p < 0.05, both). In subjects > 56 years, no significant effect of the variant was observed.

Conclusion

The age-related reduced risk of composite endpoint in rs10754555 G-allele carriers accompanied by diminished NLRP3 mRNA expression is hypothesis generating and needs to be further explored. The study is registered at http://www.clinicaltrials.gov, with identification number NCT00222261.

Cigarette smoke-induced gasdermin D activation in bronchoalveolar macrophages and bronchial epithelial cells dependently on NLRP3

Chronic pulmonary inflammation and chronic obstructive pulmonary disease (COPD) are major health issues largely due to air pollution and cigarette smoke (CS) exposure. The role of the innate receptor NLRP3 (nucleotide-binding domain and leucine-rich repeat containing protein 3) orchestrating inflammation through formation of an inflammasome complex in CS-induced inflammation or COPD remains controversial. Using acute and subchronic CS exposure models, we found that Nlrp3-deficient mice or wild-type mice treated with the NLRP3 inhibitor MCC950 presented an important reduction of inflammatory cells recruited into the bronchoalveolar space and of pulmonary inflammation with decreased chemokines and cytokines production, in particular IL-1β demonstrating the key role of NLRP3. Furthermore, mice deficient for Caspase-1/Caspase-11 presented also decreased inflammation parameters, suggesting a role for the NLRP3 inflammasome. Importantly we showed that acute CS-exposure promotes NLRP3-dependent cleavage of gasdermin D in macrophages present in the bronchoalveolar space and in bronchial airway epithelial cells. Finally, Gsdmd-deficiency reduced acute CS-induced lung and bronchoalveolar space inflammation and IL-1β secretion. Thus, we demonstrated in our model that NLRP3 and gasdermin D are key players in CS-induced pulmonary inflammation and IL-1β release potentially through gasdermin D forming-pore and/or pyroptoctic cell death.

Inflammasome involvement in CS-induced damage in HaCaT keratinocytes

Cigarette smoke (CS) alters cutaneous biological processes such as redox homeostasis and inflammation response that might be involved in promoting skin inflammatory conditions. Exposure to CS has also been linked to a destabilization of the NLRP3 inflammasome in pollution target tissues such as the lung epithelium, resulting in a more vulnerable immunological response to several exogenous and endogenous stimuli related to oxidative stress. Thus, CS has an adverse effect on host defense, increasing the susceptibility to develop lung infections and pathologies. In the skin, another direct target of pollution, inflammasome disorders have been linked to an increasing number of diseases such as melanoma, psoriasis, vitiligo, atopic dermatitis, and acne, all conditions that have been connected directly or indirectly to pollution exposure. The inflammasome machinery is an important innate immune sensor in human keratinocytes. However, the role of CS in the NLRP1 and NLRP3 inflammasome in the cutaneous barrier has still not been investigated. In the present study, we were able to determine in keratinocytes exposed to CS an increased oxidative damage evaluated by 4-HNE protein adduct and carbonyl formation. Of note is that, while CS inhibited NLRP3 activation, it was able to activate NLRP1, leading to an increased secretion of the proinflammatory cytokines IL-1β and IL-18. This study highlights the importance of the inflammasome machinery in CS that more in general, in pollution, affects cutaneous tissues and the important cross-talk between different members of the NLRP inflammasome family.

Molecular insights of cigarette smoke condensate-activated NLRP3 inflammasome in THP-1 cells in a stage-specific atherogenesis

BACKGROUND

Smoking induces excessive inflammation which is associated with all the stages of atherosclerosis. Earlier, we reported Nod-like receptor protein 3 (NLRP3) inflammasome activation as a pro-atherosclerotic property of cigarette smoking. In the present study, we aimed to explore the underlying detailed upstream mechanism and the cellular status of putative downstream molecules of cigarette smoke condensate (CSC)-activated NLRP3 inflammasome in atherosclerotic disease.

METHODS AND RESULTS

THP-1 monocytes, macrophages and foam cells represent crucial stages of atherogenesis as initiation, progression and development. To determine the upstream molecular regulators of smoking-induced NLRP3 inflammasome in atherogenesis, Myeloid differentiation primary response 88/Nuclear Factor kappa-light-chain-enhancer of activated B cells (MyD88/NF-κB) and Suppressor of cytokine signaling 3/Signal transduction and activator of transcription 3 (SOCS3/STAT3) pathways were elucidated. Stage-specific THP-1 cells were treated with MyD88 and SOCS3/STAT3 inhibitors. The results showed that MyD88 inhibition markedly attenuated the expression of NLRP3 markers (NLRP3, caspase-1, Interleukin (IL)-1β and IL-18), IL-6, SOCS3 and NF-κB. Moreover, the secretory levels of pro-cytokines were also significantly reduced in culture media. In contrast, no changes were observed with SOCS3/STAT3 inhibitor. Further, ac-vyad-cmk, an inflammasome inhibitor was used to explore the downstream targets of CSC-activated NLRP3 inflammasome in atherosclerotic process. The transcriptional profiling of 25 atherosclerotic markers was carried out using ExProfile™ Custom Gene qPCR Arrays. CSC exposure upregulated the expression of 17 genes and downregulated 4 genes in a stage-specific manner. Inhibitory experiments showed aberrant changes in CSC-regulated genes. Altogether, 15 molecules were common in all three stages.

CONCLUSION

The findings may suggest that MyD88/NF-κB pathway is an upstream regulator of NLRP3 inflammasome underlying smoking-induced atherosclerosis. Notably, 15 atherosclerotic molecules associated with endothelial dysfunction, scavenger receptors, cholesterol esterification and matrix-metalloproteins were found downstream to CSC-activated NLRP3 inflammasome.

Activation of NLRP3 inflammasome assembly is associated with smoking status of patients with coronary artery disease

OBJECTIVE

Cigarette smoke is considered as a sterile inflammatory stimulus which triggers an innate immune response, accountable for vascular events. Previously, we reported smoking-induced NLRP3 inflammasome activation in the pathogenesis of atherosclerosis through caspase-1 activation and secretion of pro-cytokines (interleukin (IL)-1β and IL-18) in vitro and in vivo. Therefore, the present study aimed to reconnoitre the association of cigarette smoking and NLRP3 inflammasome activation ex vivo in human subjects with coronary atherosclerosis.

METHODS AND RESULTS

In order to establish and validate the association between smoking status and NLRP3 inflammasome ex vivo, mononuclear cells were isolated from smokers with angiographically-proven coronary artery disease (CAD); non-smokers with CAD; smokers without CAD, and healthy non-smokers (controls) (n = 20 each). The transcriptional and translational expression of NLRP3 inflammasome markers i.e. NLRP3, pro-caspase-1, caspase-1, pro-IL-1β, IL-1β, pro-IL-18 and IL-18 was significantly increased (2 to 7-fold) in smokers with CAD vs non-smokers with CAD; and smokers without CAD vs non-smoker controls. In addition, the oxidative stress, an upstream mediator of NLRP3 inflammasome was evaluated and found to be significantly augmented in smokers vs non-smokers (with and without CAD respectively). Further, the levels of serum cotinine, oxidative stress markers (8-isoprostane and 8-oxo-2́'-deoxyguanosine), caspase-1 and pro-cytokines (IL-1β and IL-18) were also higher in smokers vs non-smokers. Moreover, the levels of pro-cytokines were positively correlated with caspase-1 and serum cotinine, corroborating the secretion of cytokines in a caspase-1-dependent manner.

CONCLUSION

Our data may imply NLRP3 inflammasome as a mediator of the pro-atherosclerotic property of cigarette smoking in atherosclerotic patients.