Introduction: Cigarette smoke (CS) exacerbates the severity of diseases not only in lungs, but also in systemic organs having no direct contact with smoke. In addition, smoking during pregnancy can have severe health consequences for both the mother and the fetus. Therefore, our aim was to evaluate effects of prenatal exposure to CS on acetaminophen (APAP)-induced acute liver injury (ALI) in offspring. Methods: Female C57BL/6 mice on day 6 of gestation were exposed to mainstream CS (MSCS) at 0, 150, 300, or 600 μg/L for 2 h a day, 5 days a week for 2 weeks using a nose-only exposure system. At four weeks old, male offspring mice were injected intraperitoneally with a single dose of APAP at 300 mg/kg body weight to induce ALI. Results: Maternal MSCS exposure significantly amplified pathological effects associated with ALI as evidenced by elevated serum alanine aminotransferase levels, increased hepatocellular apoptosis, higher oxidative stress, and increased inflammation. Interestingly, maternal MSCS exposure reduced microRNA (miR)-34a-5p expression in livers of offspring. Moreover, treatment with a miR-34a-5p mimic significantly mitigated the severity of APAP-induced hepatotoxicity. Overexpression of miR-34a-5p completely abrogated adverse effects of maternal MSCS exposure in offspring with ALI. Mechanistically, miR-34a-5p significantly decreased expression levels of hepatocyte nuclear factor 4 alpha, leading to down-regulated expression of cytochrome P450 (CYP)1A2 and CYP3A11. Discussion: Prenatal exposure to MSCS can alter the expression of miRNAs, even in the absence of additional MSCS exposure, potentially increasing susceptibility to APAP exposure in male offspring mice.

Characterization of chemical composition in cigarette smoke is essential for establishing smoke-related exposure estimates. Currently used methods require complex sample preparation with limited capability for obtaining accurate chemical information. We have developed an in situ solid-phase microextraction (SPME) method for online processing of smoke aerosols and directly coupling the SPME probes with confined-space direct analysis in real time (cDART) ion source for high-resolution mass spectrometry (MS) analysis. In a confined space, the substances from SPME probes can be efficiently desorbed and ionized using the DART ion source, and the diffusion and evaporation of volatile species into the open air can be largely avoided. Using SPME-cDART-MS, mainstream smoke (MSS) and side-stream smoke (SSS) can be investigated and the whole analytical protocol can be accomplished in a few min. More than five hundred substances and several classes of compounds were detected and identified. The relative contents of 13 tobacco alkaloids were compared between MSS and SSS. Multivariate data analysis unveiled differences between different types of cigarette smoke and also discovered the characteristic ions. The method is reliable with good reproducibility and repeatability, and has the potential to be quantitative. This study provides a simple and high-efficiency method for smokeomics profiling of complex aerosol samples with in situ online extraction of volatile samples, and direct integration of extracted probes with a modified ambient ionization technique.

OBJECTIVE: Recently, the detrimental effect of cigarette smoking on muscle metabolism has attracted much attention, but the relationship between cigarette smoking and muscle mass is poorly understood. Thus, this study investigated the association between exposure to cigarette smoke, defined based on serum cotinine, and muscle mass in the US population.
METHODS: We utilized National Health and Nutrition Examination Survey (NHANES) data between 2011 and 2018 for analysis. Data on serum cotinine, muscle mass (quantified by appendicular skeletal muscle mass index, ASMI), and covariates were extracted and analyzed. Weighted multivariate linear regression analyses and smooth curve fittings were performed to investigate the association between serum cotinine and ASMI. Subgroup analyses were stratified by gender, race and smoking status. When nonlinearity was detected, the threshold effects were analyzed using a two-piecewise linear regression model.
RESULTS: In total, 8004 participants were included for analysis. The serum level of cotinine was negatively associated with ASMI in the fully adjusted model. Furthermore, comparing participants in the highest vs. the lowest tertile of serum cotinine, we found that ASMI decreased by 0.135 Kg/m2. In subgroup analysis stratified by gender and race, the association between serum cotinine and ASMI remained significant in all genders and races. In addition, the association remained significant among current and former smokers, but not among those who never smoked. Smooth curve fittings showed nonlinear relationships between serum cotinine and ASMI, with the inflection points identified at 356 ng/mL.
CONCLUSIONS: Our study revealed that serum cotinine was negatively related to muscle mass. This finding improves our understanding of the deleterious effects of cigarette smoking on muscle mass and highlights the importance of smoking cessation for muscle health.

UNASSIGNED: To explore the effects and mechanisms of bilirubin on mitochondrial function and type of macrophage cell death after exposure to cigarette smoke extract (CSE).
UNASSIGNED: RAW264.7 macrophages were treated with different concentrations of CSE and bilirubin solutions and divided into four groups: control, CSE, bilirubin, and bilirubin + CSE groups. The necrotic and apoptotic states of the macrophages were determined using an Annexin V-fluorescein 5-isothiocyanate/propidium iodide (FITC/PI) staining kit. Cytoplasmic NOD-like receptor family, pyrin domain containing 3 (NLRP3) expression in macrophages was detected by immunofluorescence and the levels of IL-1β and IL-18 in the supernatants of culture medium were detected by enzyme linked immunosorbent assay (ELISA) test. A JC-1 mitochondrial membrane potential detection kit was used to assess mitochondrial membrane damage and the adenosine triphosphate (ATP) assay kit was used to determine intracellular ATP levels. After the macrophages were stained with reactive oxygen species (ROS) specific dye, 2\',7\'-Dichlorodihydrofluorescein diacetate (DCFH-DA), the fluorescence intensity and proportion of ROS-positive macrophages were measured using flow cytometry.
UNASSIGNED: We observed that compared with those of 0 μM (control group), concentrations of 5, 10, or 20 μΜ bilirubin significantly decreased cell viability, which was increased by bilirubin exposure below 1 μM. The effect of CSE on macrophage viability was concentration- and time-dependent. Bilirubin of 0.2 μM could alleviate the inhibition of macrophage viability caused by 5% CSE. In addition, bilirubin intervention could reduce the occurrence of necrosis and pyroptosis to a certain extent.
UNASSIGNED: CSE could cause mitochondrial dysfunction in macrophages, as demonstrated by a decrease in mitochondrial membrane potential and intracellular ATP levels and an increase in ROS production, while bilirubin could relieve mitochondrial dysfunction caused by CSE.

Cigarette smoke (CS) is a major risk factor for chronic lung diseases and promotes activation of pattern recognition receptors in the bronchial epithelium. NOD-like receptor family, pyrin domain-containing 3 (NLRP3) is a pattern recognition receptor whose activation leads to caspase-1 cleavage, maturation/release of IL-1β and IL-18, and eventually pyroptosis. Whether the NLRP3 inflammasome participates in CS-induced inflammation in bronchial epithelial cells is still unclear. Herein, we evaluated the involvement of NLRP3 in CS-induced inflammatory responses in human primary bronchial epithelial cells. To this purpose, human primary bronchial epithelial cells were stimulated with CS extracts (CSE) and lytic cell death, caspase activation (-1, -8, -3/7), cytokine release (IL-1β, IL-18, and IL-8), NLRP3, pro-IL-1β/pro-IL-18 mRNA, and protein expression were measured. The impact of inhibitors of NLRP3 (MCC950), caspases, and the effect of the antioxidant N-acetyl cysteine were evaluated. We found that CSE increased pro-IL-1β expression and induced activation of caspase-1 and release of IL-1β and IL-18. These events were independent of NLRP3 and we found that NLRP3 was not expressed. N-acetyl cysteine reverted CSE-induced caspase-1 activation. Overall, our findings support that the bronchial epithelium may play a central role in the release of IL-1 family cytokines independently of NLRP3 in the lungs of smokers.

Smoking is a well-established risk factor for several oral diseases, including oral cancer, oral leukoplakia and periodontitis, primarily related to reactive oxygen species (ROS). SS-31, a mitochondria-targeting tetrapeptide, has exhibited demonstrable efficacy in medical conditions by attenuating mitochondrial ROS production. However, its potential in the treatment of oral diseases remains underexplored. The aim of this study was to investigate the therapeutic potential of SS-31 in mitigating smoking-induced oral epithelial injury. Through in vitro experiments, our results indicate that SS-31 plays a protective role against cigarette smoke extract (CSE) by reducing oxidative stress, attenuating inflammatory response, and restoring mitochondrial function. Furthermore, we found that mitophagy, regulated by PINK1 (PTEN-induced putative kinase 1)/Parkin (Parkin RBR E3 ubiquitin-protein ligase), was critical for the protective role of SS-31. Our findings offer valuable insights into SS-31\'s therapeutic potential in mitigating CSE-induced oxidative stress, inflammatory response, and mitochondrial dysfunction in oral epithelial cells. This study provides novel intervention targets for smoking-related oral diseases.

Notch-1 signaling plays a crucial role in stem cell maintenance and in repair mechanisms in various mucosal surfaces, including airway mucosa. Persistent injury can induce an aberrant activation of Notch-1 signaling in stem cells leading to an increased risk of cancer initiation and progression. Chronic inflammatory respiratory disorders, including Chronic Obstructive Pulmonary Disease (COPD) is associated to both over-activation of Notch-1 signaling and increased lung cancer risk. Increased oxidative stress, also due to cigarette smoke, can further contribute to promote cancer initiation and progression by amplifying inflammatory responses, by activating the Notch-1 signaling and by blocking regulatory mechanisms that inhibit the growth capacity of stem cells. This review offers a comprehensive overview on the effects of aberrant Notch-1 signaling activation in stem cells and of increased oxidative stress in the lung cancer. The putative role of natural compounds with anti-oxidant properties is also described.

Lung cancer stands as a major contributor to cancer-related fatalities globally, with cigarette smoke playing a pivotal role in its development and metastasis. Cigarette smoke is also recognized as a risk factor for bone loss disorders like osteoporosis. However, the association between cigarette smoke and another bone loss disorder, lung cancer osteolytic bone metastasis, remains largely uncertain. Our Gene Set Enrichment Analysis (GSEA) indicated that smokers among lung cancer patients exhibited higher expression levels of bone turnover gene sets. Both The Cancer Genome Atlas (TCGA) database and our clinic samples demonstrated elevated expression of the osteolytic factor IL-6 in ever-smokers with bone metastasis among lung cancer patients. Our cellular experiments revealed that benzo[α]pyrene (B[α]P) and cigarette smoke extract (CSE) promoted IL-6 production and cell migration in lung cancer. Activation of the PI3K, Akt, and NF-κB signaling pathways was involved in cigarette smoke-augmented IL-6-dependent migration. Additionally, cigarette smoke lung cancer-secreted IL-6 promoted osteoclast formation. Importantly, blocking IL-6 abolished cigarette smoke-facilitated lung cancer osteolytic bone metastasis in vivo. Our findings provide evidence that cigarette smoke is a risk factor for osteolytic bone metastasis. Thus, inhibiting IL-6 may be a valuable therapeutic strategy for managing osteolytic bone metastasis in lung cancer patients who smoke.

There is a pressing need for novel pharmacological interventions and drug delivery innovations to attenuate the cigarette smoke-associated oxidative stress and lung disease. We report here on the attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and metabolomics of Wistar rats exposed to cigarette smoke for 28 days. The animals were treated for 15 days with plain cysteamine given orally or cysteamine as nanoemulsion given orally or via inhalation. The study design also included two control groups as follows: rats exposed to cigarette smoke but did not receive a treatment (diseased control group) and rats neither exposed to cigarette smoke nor a treatment (normal control group). The targeted metabolomics using Parallel Reaction Monitoring showed that in the diseased control group, ornithine, nicotinamide, xanthine, hypoxanthine, and caprolactam were increased compared with the normal control group. In addition, (±)8(9)-DiHET, which was initially downregulated in the diseased control group, exhibited a reversal of this trend with cysteamine nanoemulsion given via inhalation. The cysteamine nanoemulsion delivered by inhalation highlighted the importance of the route of drug administration for targeting the lungs. To the best of our knowledge, this is the first work to use ATR-FTIR and metabolomics in Wistar rat lung tissues, suggesting how cysteamine nanoemulsion can potentially reduce cigarette smoke-induced oxidative damage. The metabolites reported herein have potential implications for discovery of novel theranostics and, thus, to cultivate diagnostic and therapeutic innovation for early prevention and treatment of cigarette smoke-associated lung diseases.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality globally and the risk of developing lung cancer is six times greater in individuals with COPD who smoke compared to those who do not smoke. Matrix metalloproteinases (MMPs) play a crucial role in the pathophysiology of respiratory diseases by promoting inflammation and tissue degradation. Furthermore, MMPs are involved in key processes like epithelial-to-mesenchymal transition (EMT), metastasis, and invasion in lung cancer. While EMT has traditionally been associated with the progression of lung cancer, recent research highlights its active involvement in individuals with COPD. Current evidence underscores its role in orchestrating airway remodeling, fostering airway fibrosis, and contributing to the potential for malignant transformation in the complex pathophysiology of COPD. The precise regulatory roles of diverse MMPs in steering EMT during COPD progression needs to be elucidated. Additionally, the less-understood aspect involves how these MMPs bi-directionally activate or regulate various EMT-associated signaling cascades during COPD progression. This review article explores recent advancements in understanding MMPs\' role in EMT during COPD progression and various pharmacological approaches to target MMPs. It also delves into the limitations of current MMP inhibitors and explores novel, advanced strategies for inhibiting MMPs, potentially offering new avenues for treating respiratory diseases.