Evidence for the immunosuppressive role of nicotine on human dendritic cell functions

A multi-ancestry cerebral cortex transcriptome-wide association study identifies genes associated with smoking behaviors

Transcriptome-wide association studies (TWAS) have provided valuable insight in identifying genes that may impact cigarette smoking. Most of previous studies, however, mainly focused on European ancestry. Limited TWAS studies have been conducted across multiple ancestries to explore genes that may impact smoking behaviors. In this study, we used cis-eQTL data of cerebral cortex from multiple ancestries in MetaBrain, including European, East Asian, and African samples, as reference panels to perform multi-ancestry TWAS analyses on ancestry-matched GWASs of four smoking behaviors including smoking initiation, smoking cessation, age of smoking initiation, and number of cigarettes per day in GWAS & Sequencing Consortium of Alcohol and Nicotine use (GSCAN). Multiple-ancestry fine-mapping approach was conducted to identify credible gene sets associated with these four traits. Enrichment and module network analyses were further performed to explore the potential roles of these identified gene sets. A total of 719 unique genes were identified to be associated with at least one of the four smoking traits across ancestries. Among those, 249 genes were further prioritized as putative causal genes in multiple ancestry-based fine-mapping approach. Several well-known smoking-related genes, including PSMA4, IREB2, and CHRNA3, showed high confidence across ancestries. Some novel genes, e.g., TSPAN3 and ANK2, were also identified in the credible sets. The enrichment analysis identified a series of critical pathways related to smoking such as synaptic transmission and glutamate receptor activity. Leveraging the power of the latest multi-ancestry GWAS and eQTL data sources, this study revealed hundreds of genes and relevant biological processes related to smoking behaviors. These findings provide new insights for future functional studies on smoking behaviors.

Nicotinic receptors in airway disease

With continued smoking of tobacco products and expanded use of nicotine delivery devices worldwide, understanding the impact of smoking and vaping on respiratory health remains a major global unmet need. Although multiple studies have shown a strong association between smoking and asthma, there is a relative paucity of mechanistic understanding of how elements in cigarette smoke impact the airway. Recognizing that nicotine is a major component in both smoking and vaping products, it is critical to understand the mechanisms by which nicotine impacts airways and promotes lung diseases such as asthma. There is now increasing evidence that α7 nicotinic acetylcholine receptors (α7nAChRs) are critical players in nicotine effects on airways, but the mechanisms by which α7nAChR influences different airway cell types have not been widely explored. In this review, we highlight and integrate the current state of knowledge regarding nicotine and α7nAChR in the context of asthma and identify potential approaches to alleviate the impact of smoking and vaping on the lungs.

Nicotinic acetylcholine receptors in cancer: Limitations and prospects

Nicotinic acetylcholine receptors (nAChRs) have long been considered to solely mediate neurotransmission. However, their widespread distribution in the human body suggests a more diverse physiological role. Additionally, the expression of nAChRs is increased in certain cancers, such as lung cancer, and has been associated with cell proliferation, epithelial-to-mesenchymal cell transition, angiogenesis and apoptosis prevention. Several compounds that interact with these receptors have been identified as potential therapeutic agents. They have been tested as drugs for treating nicotine addiction, alcoholism, depression, pain and Alzheimer's disease. This review focuses on nAChR-mediated signalling in cancer, presenting opportunities for the development of innovative nAChR-based anticancer drugs. It displays the differences in expression of each nAChR subunit between normal and cancer cells for selected cancer types, highlighting their possible involvement in specific cases. Antagonists of nAChRs that could complement existing cancer therapies are summarised and critically discussed. We hope that this review will stimulate further research on the role of nAChRs in cancer potentially leading to innovative cancer therapies.

Panel of miR-150 and linc00673, regulators of CCR6/CCL20 may serve as non-invasive diagnostic marker of non-small cell lung cancer

The C-C motif ligand 20 (CCL20) is a chemokine that specifically binds to the chemokine receptor 6 (CCR6) and the CCL20/CCR6 axis has been implicated in the non-small lung cancer (NSCLC) development and progression. Its expression is regulated by mutual interactions of non-coding RNAs (ncRNAs). This goals of presented study was to evaluate the expression level of CCR6/CCL20 mRNA in NSCLC tissue comparative to selected ncRNAs: miR-150, linc00673. The expression level of the studied ncRNAs was also assessed in serum extracellular vesicles (EVs). Thirty patients (n = 30) were enrolled as the study cohort. Total RNA was isolated from tumor tissue, adjacent macroscopically unchanged tissue and serum EVs. The expression level of studied genes and ncRNAs were estimated based on the qPCR method. Higher expression level of CCL20 mRNA but lower expression level of CCR6 mRNA were observed in tumor in comparison to control tissue. Relative to the smoking status, higher CCL20 (p < 0.05) and CCR6 mRNA (p > 0.05) expression levels were observed in current smokers than in never smokers. In serum EVs the expression level of miR-150 has a negative correlation with AJCC tumor staging, whereas the expression level of linc00673 positively correlated (p > 0.05). The lower expression level of miR-150 and higher expression level of linc00673 in serum EVs were observed in NSCLC patients with lymph nodes metastases (p > 0.05). Regarding the histopathological type, significantly lower expression level of miR-150 and higher expression level of linc00673 were observed in the serum EVs of patients with AC compared to patient with SCC. Our findings revealed that smoking significantly changed the expression level of CCL20 mRNA in NSCLC tissue. Changes in expression levels of miR-150 and linc00673 in the serum EVs of NSCLC patients in relation to presence of lymph node metastases and the stage of cancer development may serve as a non-invasive molecular biomarkers of tumor progression. Furthermore, expression levels of miR-150 and linc00673 may serve as non-intrusive diagnostic biomarkers differentiating adenocarcinoma from squamous cell carcinoma.

The controversial effect of smoking and nicotine in SARS-CoV-2 infection

The effects of nicotine and cigarette smoke in many diseases, notably COVID-19 infection, are being debated more frequently. The current basic data for COVID-19 is increasing and indicating the higher risk of COVID-19 infections in smokers due to the overexpression of corresponding host receptors to viral entry. However, current multi-national epidemiological reports indicate a lower incidence of COVID-19 disease in smokers. Current data indicates that smokers are more susceptible to some diseases and more protective of some other. Interestingly, nicotine is also reported to play a dual role, being both inflammatory and anti-inflammatory. In the present study, we tried to investigate the effect of pure nicotine on various cells involved in COVID-19 infection. We followed an organ-based systematic approach to decipher the effect of nicotine in damaged organs corresponding to COVID-19 pathogenesis (12 related diseases). Considering that the effects of nicotine and cigarette smoke are different from each other, it is necessary to be careful in generalizing the effects of nicotine and cigarette to each other in the conducted researches. The generalization and the undifferentiation of nicotine from smoke is a significant bias. Moreover, different doses of nicotine stimulate different effects (dose-dependent response). In addition to further assessing the role of nicotine in COVID-19 infection and any other cases, a clever assessment of underlying diseases should also be considered to achieve a guideline for health providers and a personalized approach to treatment.

Modulation of oxidative phosphorylation and mitochondrial biogenesis by cigarette smoke influence the response to immune therapy in NSCLC patients

The treatment regimen of non-small cell lung cancer (NSCLC) has drastically changed owing to the superior anti-cancer effects generated by the immune-checkpoint blockade (ICB). However, only a subset of patients experience benefit after receiving ICBs. Therefore, it is of paramount importance to increase the response rate by elucidating the underlying molecular mechanisms and identifying novel therapeutic targets to enhance the efficacy of IBCs in non-responders. We analyzed the progression-free survival (PFS) and overall survival (OS) of 295 NSCLC patients who received anti-PD-1 therapy by segregating them with multiple clinical factors including sex, age, race, smoking history, BMI, tumor grade and subtype. We also identified key signaling pathways and mutations that are enriched in patients with distinct responses to ICB by gene set enrichment analysis (GSEA) and mutational analyses. We found that former and current smokers have a higher response rate to anti-PD-1 treatment than non-smokers. GSEA results revealed that oxidative phosphorylation (OXPHOS) and mitochondrial related pathways are significantly enriched in both responders and smokers, suggesting a potential role of cellular metabolism in regulating immune response to ICB. We also demonstrated that all-trans retinoic acid (ATRA) which enhances mitochondrial function significantly enhanced the efficacy of anti-PD-1 treatment in vivo. Our clinical and bioinformatics based analyses revealed a connection between smoking induced metabolic switch and the response to immunotherapy, which can be the basis for developing novel combination therapies that are beneficial to never smoked NSCLC patients.

α7- and α9-Containing Nicotinic Acetylcholine Receptors in the Functioning of Immune System and in Pain

Nicotinic acetylcholine receptors (nAChRs) present as many different subtypes in the nervous and immune systems, muscles and on the cells of other organs. In the immune system, inflammation is regulated via the vagus nerve through the activation of the non-neuronal α7 nAChR subtype, affecting the production of cytokines. The analgesic properties of α7 nAChR-selective compounds are mostly based on the activation of the cholinergic anti-inflammatory pathway. The molecular mechanism of neuropathic pain relief mediated by the inhibition of α9-containing nAChRs is not fully understood yet, but the role of immune factors in this process is becoming evident. To obtain appropriate drugs, a search of selective agonists, antagonists and modulators of α7- and α9-containing nAChRs is underway. The naturally occurring three-finger snake α-neurotoxins and mammalian Ly6/uPAR proteins, as well as neurotoxic peptides α-conotoxins, are not only sophisticated tools in research on nAChRs but are also considered as potential medicines. In particular, the inhibition of the α9-containing nAChRs by α-conotoxins may be a pathway to alleviate neuropathic pain. nAChRs are involved in the inflammation processes during AIDS and other viral infections; thus they can also be means used in drug design. In this review, we discuss the role of α7- and α9-containing nAChRs in the immune processes and in pain.

Aerosolized nicotine from e-cigarettes alters gene expression, increases lung protein permeability, and impairs viral clearance in murine influenza infection

E-cigarette use has rapidly increased as an alternative means of nicotine delivery by heated aerosolization. Recent studies demonstrate nicotine-containing e-cigarette aerosols can have immunosuppressive and pro-inflammatory effects, but it remains unclear how e-cigarettes and the constituents of e-liquids may impact acute lung injury and the development of acute respiratory distress syndrome caused by viral pneumonia. Therefore, in these studies, mice were exposed one hour per day over nine consecutive days to aerosol generated by the clinically-relevant tank-style Aspire Nautilus aerosolizing e-liquid containing a mixture of vegetable glycerin and propylene glycol (VG/PG) with or without nicotine. Exposure to the nicotine-containing aerosol resulted in clinically-relevant levels of plasma cotinine, a nicotine-derived metabolite, and an increase in the pro-inflammatory cytokines IL-17A, CXCL1, and MCP-1 in the distal airspaces. Following the e-cigarette exposure, mice were intranasally inoculated with influenza A virus (H1N1 PR8 strain). Exposure to aerosols generated from VG/PG with and without nicotine caused greater influenza-induced production in the distal airspaces of the pro-inflammatory cytokines IFN-γ, TNFα, IL-1β, IL-6, IL-17A, and MCP-1 at 7 days post inoculation (dpi). Compared to the aerosolized carrier VG/PG, in mice exposed to aerosolized nicotine there was a significantly lower amount of Mucin 5 subtype AC (MUC5AC) in the distal airspaces and significantly higher lung permeability to protein and viral load in lungs at 7 dpi with influenza. Additionally, nicotine caused relative downregulation of genes associated with ciliary function and fluid clearance and an increased expression of pro-inflammatory pathways at 7 dpi. These results show that (1) the e-liquid carrier VG/PG increases the pro-inflammatory immune responses to viral pneumonia and that (2) nicotine in an e-cigarette aerosol alters the transcriptomic response to pathogens, blunts host defense mechanisms, increases lung barrier permeability, and reduces viral clearance during influenza infection. In conclusion, acute exposure to aerosolized nicotine can impair clearance of viral infection and exacerbate lung injury, findings that have implications for the regulation of e-cigarette products.

Nicotine Exerts Cytotoxic Effects in a Panel of Healthy Cell Lines and Strong Irritating Potential on Blood Vessels

The use of tobacco products is a major global public health issue, as it is the leading cause of preventable death worldwide. In addition, nicotine (NIC) is a key component of electronic and conventional cigarettes. Although nicotine's addictive potential is well known, its health effects are not entirely understood. Thus, the main objective of the present study was to evaluate its toxicological profile both in vitro, at the level of three healthy cell lines, and in ovo, at the level of the chorioallantoic membrane. Five different concentrations of nicotine were used in keratinocytes, cardiomyocytes, and hepatocytes for the purpose of evaluating cell viability, cell morphology, and its impact on nuclei. Additionally, the hen's egg test on the chorioallantoic membrane (HET-CAM) method was used to assess the biocompatibility and irritant potential of the chorioallantoic membrane. Across all cell lines studied, nicotine was proven to be significantly damaging to cell viability, with the highest concentration tested resulting in less than 2% viable cells. Moreover, the morphology of cells changed dramatically, with alterations in their shape and confluence. Nicotine-induced cell death appears to be apoptotic, based on its impact on the nucleus. In addition, nicotine was also found to have a very strong irritating effect on the chorioallantoic membrane. In conclusion, nicotine has an extremely strong toxicological profile, as demonstrated by the drastic reduction of cell viability and the induction of morphological changes and nuclear alterations associated with cellular apoptosis. Additionally, the HET-CAM method led to the observation of a strong irritating effect associated with nicotine.

No smoke without fire: the impact of cigarette smoking on the immune control of tuberculosis

Cigarette smoke (CS) exposure is a key risk factor for both active and latent tuberculosis (TB). It is associated with delayed diagnosis, more severe disease progression, unfavourable treatment outcomes and relapse after treatment. Critically, CS exposure is common in heavily populated areas with a high burden of TB, such as China, India and the Russian Federation. It is therefore prudent to evaluate interventions for TB while taking into account the immunological impacts of CS exposure. This review is a mechanistic examination of how CS exposure impairs innate barrier defences, as well as alveolar macrophage, neutrophil, dendritic cell and T-cell functions, in the context of TB infection and disease.

Human lung cDC1 drive increased perforin-mediated NK cytotoxicity in Chronic Obstructive Pulmonary Disease

In chronic obstructive pulmonary disease (COPD), lung natural killer cells (NKs) lyse autologous lung epithelial cells in vitro, but underlying mechanisms and their relationship to epithelial cell apoptosis in vivo are undefined. Although this cytolytic capacity of lung NKs depends on priming by dendritic cells (DC), whether priming correlates with DC maturation or is limited to a specific DC subset are also unknown. We recruited ever-smokers (≥10 pack-years) (n=96) undergoing clinically-indicated lung resections. We analyzed lung NKs for cytotoxic molecule transcripts and for cytotoxicity, which we correlated with in situ detection of activated Caspase-3/7+ airway epithelial cells. To investigate DC priming, we measured lung DC expression of CCR2, CCR7, and CX3CR1, and co-cultured peripheral blood NKs with autologous lung DC, either matured using LPS (non-obstructed smokers) or separated into conventional DC type-1 (cDC1) versus cDC type-2 (cDC2) (COPD). Lung NKs in COPD expressed more perforin (p<0.02) and granzyme B (p<0.03) transcripts; inhibiting perforin blocked in vitro killing by lung NKs. Cytotoxicity in vitro correlated significantly (S_r=0.68, p=0.0043) with numbers of apoptotic epithelial cells per airway. In non-obstructed smokers, LPS-induced maturation enhanced DC-mediated priming of blood NKs, reflected by greater epithelial cell death. Although CCR7 expression was greater in COPD in both cDC1 (p<0.03) and cDC2 (p=0.009), only lung cDC1 primed NK killing. Thus, rather than being intrinsic to those with COPD, NK priming is a capacity of human lung DC that is inducible by recognition of bacterial (and possibly other) danger signals and restricted to the cDC1 subset.

Neuroinflammation Modulation via α7 Nicotinic Acetylcholine Receptor and Its Chaperone, RIC-3

Nicotinic acetylcholine receptors (nAChRs) are widely expressed in or on various cell types and have diverse functions. In immune cells nAChRs regulate proliferation, differentiation and cytokine release. Specifically, activation of the α7 nAChR reduces inflammation as part of the cholinergic anti-inflammatory pathway. Here we review numerous effects of α7 nAChR activation on immune cell function and differentiation. Further, we also describe evidence implicating this receptor and its chaperone RIC-3 in diseases of the central nervous system and in neuroinflammation, focusing on multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Deregulated neuroinflammation due to dysfunction of α7 nAChR provides one explanation for involvement of this receptor and of RIC-3 in neurodegenerative diseases. In this review, we also provide evidence implicating α7 nAChRs and RIC-3 in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) involving neuroinflammation. Besides, we will describe the therapeutic implications of activating the cholinergic anti-inflammatory pathway for diseases involving neuroinflammation.

Impact of smoking on dendritic cells in patients with oral squamous cell carcinoma

Smoking has been shown to alter innate and adaptive immune responses and is directly associated with the onset of oral squamous cell carcinoma (OSCC). The purpose of this study was to evaluate the effect of cigarette smoke exposure on dendritic cells (DCs) from OSCC patients. CD1a and CD83 antibodies were used to identify immature and mature DCs, respectively, by immunohistochemistry in OSCC samples of 24 smokers and 24 non-smokers. Density of DCs was calculated in intra and peritumoral areas. Clinical and microscopic findings were reviewed and analyzed for all patients. Smokers with OSCC had a lower density of intra and peritumoral DCs when compared to non-smokers. Tumors classified as moderately/poorly differentiated had lower peritumoral CD1a+ DCs than well-differentiated tumors (p < 0.001). Smoking contributed to a depletion of immature and mature DCs in the OSCC.

Increased Expression of Proatherogenic Proteins in Immune Cell Subtypes in Tobacco Cigarette Smokers But Not in Electronic Cigarette Vapers

It is unclear how oxidative stress triggered by smoking and vaping may alter specific immune cell subsets. In this study, we showed that tobacco cigarette smoking, but not electronic-cigarette vaping, is associated with increased expression of major proteins in the toll-like receptor 4 (TLR4) inflammasome-interleukin (IL)-6 signalling axis in monocyte subtypes and T cells. TLR4 senses oxidative stress in immune cells caspase-1 is a key protein of inflammasome activation, and IL-6R-α is the receptor for IL-6 that drives proatherogenic IL-6 signalling. These findings implicate the non-nicotine, pro-oxidant toxicants in tobacco cigarette smoke as instigators of increased expression of key proteins in the TLR4-inflammasome-IL-6 axis that contribute to atherogenesis.

Cholinergic System and Its Therapeutic Importance in Inflammation and Autoimmunity

Neurological and immunological signals constitute an extensive regulatory network in our body that maintains physiology and homeostasis. The cholinergic system plays a significant role in neuroimmune communication, transmitting information regarding the peripheral immune status to the central nervous system (CNS) and vice versa. The cholinergic system includes the neurotransmitter\ molecule, acetylcholine (ACh), cholinergic receptors (AChRs), choline acetyltransferase (ChAT) enzyme, and acetylcholinesterase (AChE) enzyme. These molecules are involved in regulating immune response and playing a crucial role in maintaining homeostasis. Most innate and adaptive immune cells respond to neuronal inputs by releasing or expressing these molecules on their surfaces. Dysregulation of this neuroimmune communication may lead to several inflammatory and autoimmune diseases. Several agonists, antagonists, and inhibitors have been developed to target the cholinergic system to control inflammation in different tissues. This review discusses how various molecules of the neuronal and non-neuronal cholinergic system (NNCS) interact with the immune cells. What are the agonists and antagonists that alter the cholinergic system, and how are these molecules modulate inflammation and immunity. Understanding the various functions of pharmacological molecules could help in designing better strategies to control inflammation and autoimmunity.

Cholinergic Modulation of the Immune System in Neuroinflammatory Diseases

Frequent diseases of the CNS, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and psychiatric disorders (e.g., schizophrenia), elicit a neuroinflammatory response that contributes to the neurodegenerative disease process itself. The immune and nervous systems use the same mediators, receptors, and cells to regulate the immune and nervous systems as well as neuro-immune interactions. In various neurodegenerative diseases, peripheral inflammatory mediators and infiltrating immune cells from the periphery cause exacerbation to current injury in the brain. Acetylcholine (ACh) plays a crucial role in the peripheral and central nervous systems, in fact, other than cells of the CNS, the peripheral immune cells also possess a cholinergic system. The findings on peripheral cholinergic signaling, and the activation of the “cholinergic anti-inflammatory pathway” mediated by ACh binding to α7 nAChR as one of the possible mechanisms for controlling inflammation, have restarted interest in cholinergic-mediated pathological processes and in the new potential therapeutic target for neuro-inflammatory-degenerative diseases. Herein, we focus on recent progress in the modulatory mechanisms of the cholinergic anti-inflammatory pathway in neuroinflammatory diseases.

Nicotine promotes breast cancer metastasis by stimulating N2 neutrophils and generating pre-metastatic niche in lung

Smoking has a profound impact on tumor immunity, and nicotine, which is the major addictive component of smoke, is known to promote tumor progression despite being a non-carcinogen. In this study, we demonstrate that chronic exposure of nicotine plays a critical role in the formation of pre-metastatic niche within the lungs by recruiting pro-tumor N2-neutrophils. This pre-metastatic niche promotes the release of STAT3-activated lipocalin 2 (LCN2), a secretory glycoprotein from the N2-neutrophils, and induces mesenchymal-epithelial transition of tumor cells thereby facilitating colonization and metastatic outgrowth. Elevated levels of serum and urine LCN2 is elevated in early-stage breast cancer patients and cancer-free females with smoking history, suggesting that LCN2 serve as a promising prognostic biomarker for predicting increased risk of metastatic disease in female smoker(s). Moreover, natural compound, salidroside effectively abrogates nicotine-induced neutrophil polarization and consequently reduced lung metastasis of hormone receptor-negative breast cancer cells. Our findings suggest a pro-metastatic role of nicotine-induced N2-neutrophils for cancer cell colonization in the lungs and illuminate the therapeutic use of salidroside to enhance the anti-tumor activity of neutrophils in breast cancer patients.

Smoking is known to impact tumor immunity and promote tumor progression. Here, the authors show that chronic nicotine exposure promotes the lung pre-metastatic niche formation by recruiting pro-tumor N2-neutrophils that release lipocalin-2.

The Role of α7nAChR-Mediated Cholinergic Anti-inflammatory Pathway in Immune Cells

Alpha 7 nicotinic acetylcholine receptor (α7nAChR) is widely distributed in the nervous and non-cholinergic immune systems. It is necessary for the cholinergic transmitter to participate in the regulation of inflammatory response and is the key element of cholinergic anti-inflammatory pathway (CAP). Because of the profound impact of CAP on the immune system, α7nAChR is considered as a potential therapeutic target for the treatment of inflammatory diseases. Available evidences confirmed that manipulation of CAP by activating α7nAChR with either endogenous acetylcholine (ACh) or cholinergic agonists can substantially alleviate inflammatory responses both in vivo and in vitro. However, the mechanism through which CAP curbs the excessive pro-inflammatory responses and maintains immune homeostasis is not fully understood. Obtained clues suggest that the crosstalk between CAP and classical inflammatory pathways is the key to elucidate the anti-inflammatory mechanism, and the impacts of CAP activation in α7nAChR-expressing immune cells are the foundation of the immunoregulatory property. In this article, we review and update the knowledge concerning the progresses of α7nAChR-based CAP, including α7nAChR properties, signal transductions, interactions with classic immune pathways, and immunoregulatory functions in different immune cells. Certain critical issues to be addressed are also highlighted. By providing a panoramic view of α7nAChR, the summarized evidences will pave the way for the development of novel anti-inflammatory reagents and strategy and inspire further researches.

Allosterism of Nicotinic Acetylcholine Receptors: Therapeutic Potential for Neuroinflammation Underlying Brain Trauma and Degenerative Disorders

Inflammation is a key physiological phenomenon that can be pervasive when dysregulated. Persistent chronic inflammation precedes several pathophysiological conditions forming one of the critical cellular homeostatic checkpoints. With a steady global surge in inflammatory diseases, it is imperative to delineate underlying mechanisms and design suitable drug molecules targeting the cellular partners that mediate and regulate inflammation. Nicotinic acetylcholine receptors have a confirmed role in influencing inflammatory pathways and have been a subject of scientific scrutiny underlying drug development in recent years. Drugs designed to target allosteric sites on the nicotinic acetylcholine receptors present a unique opportunity to unravel the role of the cholinergic system in regulating and restoring inflammatory homeostasis. Such a therapeutic approach holds promise in treating several inflammatory conditions and diseases with inflammation as an underlying pathology. Here, we briefly describe the potential of cholinergic allosterism and some allosteric modulators as a promising therapeutic option for the treatment of neuroinflammation.

The effects of COVID-19 on perioperative morbidity and mortality in patients with hip fractures

AIMS

During the COVID-19 pandemic, many patients continue to require urgent surgery for hip fractures. However, the impact of COVID-19 on perioperative outcomes in these high-risk patients remains unknown. The objectives of this study were to establish the effects of COVID-19 on perioperative morbidity and mortality, and determine any risk factors for increased mortality in patients with COVID-19 undergoing hip fracture surgery.

METHODS

This multicentre cohort study included 340 COVID-19-negative patients versus 82 COVID-19-positive patients undergoing surgical treatment for hip fractures across nine NHS hospitals in Greater London, UK. Patients in both treatment groups were comparable for age, sex, body mass index, fracture configuration, and type of surgery performed. Predefined perioperative outcomes were recorded within a 30-day postoperative period. Univariate and multivariate analysis were used to identify risk factors associated with increased risk of mortality.

RESULTS

COVID-19-positive patients had increased postoperative mortality rates (30.5% (25/82) vs 10.3% (35/340) respectively, p < 0.001) compared to COVID-19-negative patients. Risk factors for increased mortality in patients with COVID-19 undergoing surgery included positive smoking status (hazard ratio (HR) 15.4 (95% confidence interval (CI) 4.55 to 52.2; p < 0.001) and greater than three comorbidities (HR 13.5 (95% CI 2.82 to 66.0, p < 0.001). COVID-19-positive patients had increased risk of postoperative complications (89.0% (73/82) vs 35.0% (119/340) respectively; p < 0.001), more critical care unit admissions (61.0% (50/82) vs 18.2% (62/340) respectively; p < 0.001), and increased length of hospital stay (mean 13.8 days (SD 4.6) vs 6.7 days (SD 2.5) respectively; p < 0.001), compared to COVID-19-negative patients.

CONCLUSION

Hip fracture surgery in COVID-19-positive patients was associated with increased length of hospital stay, more admissions to the critical care unit, higher risk of perioperative complications, and increased mortality rates compared to COVID-19-negative patients. Risk factors for increased mortality in patients with COVID-19 undergoing surgery included positive smoking status and multiple (greater than three) comorbidities. Cite this article: Bone Joint J 2020;102-B(9):1136-1145.

Impact of Key Nicotinic AChR Subunits on Post-Stroke Pneumococcal Pneumonia

Pneumonia is the most frequent severe medical complication after stroke. An overactivation of the cholinergic signaling after stroke contributes to immunosuppression and the development of spontaneous pneumonia caused by Gram-negative pathogens. The α7 nicotinic acetylcholine receptor (α7nAChR) has already been identified as an important mediator of the anti-inflammatory pathway after stroke. However, whether the α2, α5 and α9/10 nAChR expressed in the lung also play a role in suppression of pulmonary innate immunity after stroke is unknown. In the present study, we investigate the impact of various nAChRs on aspiration-induced pneumonia after stroke. Therefore, α2, α5, α7 and α9/10 nAChR knockout (KO) mice and wild type (WT) littermates were infected with Streptococcus pneumoniae (S. pneumoniae) three days after middle cerebral artery occlusion (MCAo). One day after infection pathogen clearance, cellularity in lung and spleen, cytokine secretion in bronchoalveolar lavage (BAL) and alveolar-capillary barrier were investigated. Here, we found that deficiency of various nAChRs does not contribute to an enhanced clearance of a Gram-positive pathogen causing post-stroke pneumonia in mice. In conclusion, these findings suggest that a single nAChR is not sufficient to mediate the impaired pulmonary defense against S. pneumoniae after experimental stroke.

Electronic cigarette vapour moderately stimulates pro-inflammatory signalling pathways and interleukin-6 production by human monocyte-derived dendritic cells

Dendritic cells (DCs) are professional antigen presenting cells that play a critical role in bridging innate and adaptive immunity. Numerous studies have shown that tobacco constituents present in conventional cigarettes affect the phenotype and function of DCs; however, no studies have examined the effects of vapour from E-cigarettes on human DCs. Here, the effects of E-cigarette vapour extract (ECVE) on the phenotype and function of DCs were investigated by creating an in vitro cell culture model using human monocyte-derived DCs (MoDCs). Immature DCs were generated from peripheral blood monocytes and mature DCs were then produced by treatment with LPS or Poly I:C for 24 h. For LPS-matured DCs, 3% ECVE treatment slightly suppressed HLA-DR and CD86 expression, whereas 1% ECVE treatment enhanced IL-6 production. The overall expression of 29 signalling molecules and other cytoplasmic proteins (mainly associated with DC activation) was significantly upregulated in immature DCs by 1% ECVE, and in LPS-treated DCs by 3% ECVE. In particular, the condition that induced IL-6 production also upregulated MAPK pathway activation. These findings indicate that E-cigarette vapour moderately affects human DCs, but the effects are less pronounced than those reported for tobacco smoke.

Smoking Cessation as a Public Health Measure to Limit the Coronavirus Disease 2019 Pandemic

The novel coronavirus disease 2019 (COVID-19) has already evolved into a rapidly expanding pandemic. Risk factors for COVID-19, such as cardiovascular disease, chronic obstructive pulmonary disease and diabetes, are all strongly associated with smoking habits. The effects of cigarette smoking on the transmission of the virus and worsening of COVID-19 have been less addressed. Emerging data indicate that smoking history is the major determinant of worsening COVID-19 outcomes. Smoking cessation recovers airway ciliary clearance and immune function. Thus, smoking cessation awareness is strongly encouraged as a public health measure to limit the global impact of COVID-19.

Common innate pathways to autoimmune disease

Until recently, autoimmune disease research has primarily been focused on elucidating the role of the adaptive immune system. In the past decade or so, the role of the innate immune system in the pathogenesis of autoimmunity has increasingly been realized. Recent findings have elucidated paradigm-shifting concepts, for example, the implications of "trained immunity" and a dysbiotic microbiome in the susceptibility of predisposed individuals to clinical autoimmunity. In addition, the application of modern technologies such as the quantum dot (Qdot) system and 'Omics' (e.g., genomics, proteomics, and metabolomics) data-processing tools has proven fruitful in revisiting mechanisms underlying autoimmune pathogenesis and in identifying novel therapeutic targets. This review highlights recent findings discussed at the American Autoimmune Related Disease Association (AARDA) 2019 colloquium. The findings covering autoimmune diseases and autoinflammatory diseases illustrate how new developments in common innate immune pathways can contribute to the better understanding and management of these immune-mediated disorders.

Immune modulation by chronic exposure to waterpipe smoke and immediate-early gene regulation in murine lungs

OBJECTIVE

We investigated the effects of chronic waterpipe (WP) smoke on pulmonary function and immune response in a murine model using a research-grade WP and the effects of acute exposure on the regulation of immediate-early genes (IEGs).

METHODS

WP smoke was generated using three WP smoke puffing regimens based on the Beirut regimen. WP smoke samples generated under these puffing regimens were quantified for nicotine concentration. Mice were chronically exposed for 6 months followed by assessment of pulmonary function and airway inflammation. Transcriptomic analysis using RNAseq was conducted after acute exposure to characterise the IEG response. These biomarkers were then compared with those generated after exposure to dry smoke (without water added to the WP bowl).

RESULTS

We determined that nicotine composition in WP smoke ranged from 0.4 to 2.5 mg per puffing session. The lung immune response was sensitive to the incremental severity of chronic exposure, with modest decreases in airway inflammatory cells and chemokine levels compared with air-exposed controls. Pulmonary function was unmodified by chronic WP exposure. Acute WP exposure was found to activate the immune response and identified known and novel IEG as potential biomarkers of WP exposure.

CONCLUSION

Chronic exposure to WP smoke leads to immune suppression without significant changes to pulmonary function. Transcriptomic analysis of the lung after acute exposure to WP smoke showed activation of the immune response and revealed IEGs that are common to WP and dry smoke, as well as pools of IEGs unique to each exposure, identifying potential biomarkers specific to WP exposure.

Comparing progression molecular mechanisms between lung adenocarcinoma and lung squamous cell carcinoma based on genetic and epigenetic networks: big data mining and genome-wide systems identification

Non-small-cell lung cancer (NSCLC) is the predominant type of lung cancer in the world. Lung adenocarcinoma (LADC) and lung squamous cell carcinoma (LSCC) are subtypes of NSCLC. We usually regard them as different disease due to their unique molecular characteristics, distinct cells of origin and dissimilar clinical response. However, the differences of genetic and epigenetic progression mechanism between LADC and LSCC are complicated to analyze. Therefore, we applied systems biology approaches and big databases mining to construct genetic and epigenetic networks (GENs) with next-generation sequencing data of LADC and LSCC. In order to obtain the real GENs, system identification and system order detection are conducted on gene regulatory networks (GRNs) and protein-protein interaction networks (PPINs) for each stage of LADC and LSCC. The core GENs were extracted via principal network projection (PNP). Based on the ranking of projection values, we got the core pathways in respect of KEGG pathway. Compared with the core pathways, we found significant differences between microenvironments, dysregulations of miRNAs, epigenetic modifications on certain signaling transduction proteins and target genes in each stage of LADC and LSCC. Finally, we proposed six genetic and epigenetic multiple-molecule drugs to target essential biomarkers in each progression stage of LADC and LSCC, respectively.

Influence of single-nucleotide polymorphisms in the IFNG towards susceptibility to tuberculosis in a Pakistani population

Tuberculosis (TB) is a global issue as one-third of the population worldwide is considered to be infected. TB has become a critical public health problem as a result of increasing drug resistance, which poses a challenge to current control strategies. Similar to environmental factors, genetic makeup of the host equally contributes to disease onset. We performed genotypic analysis to examine the relationship between IFNG and TB onset and drug resistance in a Pakistani population comprising 689 subjects. Notable differences were observed in the IFNG polymorphism (+874T/A) between the case and control groups. The frequency of the wild-type genotype (TT) in the controls (43.2%) was significantly higher than in the cases (25.3%) (odds ratio [OR] = 0.77, p < 0.0001), while the mutant genotype frequency (AA) (38.57%) in the cases was significantly higher than in the controls (22.6%) (OR = 1.46, p < 0.0001). The heterozygous genotype frequency (TA) did not significantly differ between the control and case groups. Compared with the controls, the variant allele (A) was approximately twice as frequent in the cases. Females and older people have a higher chance of disease development. Finally, the IFNG (+874T/A) polymorphism was not associated with drug sensitivity or resistance. However, a genotypic polymorphism of IFNG (+874T/A) was significantly associated with susceptibility to TB, and the T allele conferred protection against TB. Additional studies involving larger cohorts are needed to further explore this relationship between genetics and disease vulnerability.

Associations of first trimester co-use of tobacco and Cannabis with prenatal immune response and psychosocial well-being

PURPOSE

This study aims to describe the association of first trimester co-use of tobacco and cannabis with maternal immune response and psychosocial well-being, relative to tobacco use only.

METHODS

A preliminary midpoint analysis included 138 pregnant women with biologically verified tobacco use, 38 of whom (28%) also tested positive for recent cannabis use. Maternal perceived stress (Perceived Stress Scale), depressive symptoms (Edinburgh Postnatal Depression Scale), and serum immune markers (IL-1β, IL-2, IL-6, IL-8, IL-10, TNFα, CRP, MMP8), were collected, although cytokine data were only available for 122 women.

RESULTS

Participant average age was 29.1 years, approximately half had a high school education or less, and half were unemployed. Compared to tobacco only users, co-users were more likely to be non-White, younger and more economically disadvantaged. In the adjusted linear regression models, TNF-α levels were significantly lower among co-users relative to tobacco only users, after adjusting for age, race/ethnicity, body mass index and tobacco use group (tobacco cigarettes, electronic nicotine delivery devices [ENDS] or both). TNF-α was the only immune marker found to be significant in this analysis. Measured stress levels (M = 5.9, SD = 3.3; potential range 0-16) and depression scores (M = 7.8, SD = 5.8; potential range 0-30) were low across all participants and did not differ as a function of co-use.

CONCLUSION

Preliminary results suggest women co-using during the first trimester exhibit decreased pro-inflammatory immune responsivity on one out of eight markers. Further research is needed to determine the impact of this immune modulation on fetal health outcomes and the unique contribution of cannabis.

Acetylcholine-treated murine dendritic cells promote inflammatory lung injury

In recent years a non-neuronal cholinergic system has been described in immune cells, which is often usually activated during the course of inflammatory processes. To date, it is known that Acetylcholine (ACh), a neurotransmitter extensively expressed in the airways, not only induces bronchoconstriction, but also promotes a set of changes usually associated with the induction of allergic/Th2 responses. We have previously demonstrated that ACh polarizes human dendritic cells (DC) toward a Th2-promoting profile through the activation of muscarinic acetylcholine receptors (mAChR). Here, we showed that ACh promotes the acquisition of an inflammatory profile by murine DC, with the increased MHC II IA^d expression and production of two cytokines strongly associated with inflammatory infiltrate and tissue damage, namely TNF-α and MCP-1, which was prevented by blocking mAChR. Moreover, we showed that ACh induces the up-regulation of M3 mAChR expression and the blocking of this receptor with tiotropium bromide prevents the increase of MHC II IAd expression and TNF-α production induced by ACh on DC, suggesting that M3 is the main receptor involved in ACh-induced activation of DC. Then, using a short-term experimental murine model of ovalbumin-induced lung inflammation, we revealed that the intranasal administration of ACh-treated DC, at early stages of the inflammatory response, might be able to exacerbate the recruitment of inflammatory mononuclear cells, promoting profound structural changes in the lung parenchyma characteristic of chronic inflammation and evidenced by elevated systemic levels of inflammatory marker, TNF-α. These results suggest a potential role for ACh in the modulation of immune mechanisms underlying pulmonary inflammatory processes.

Genetic polymorphism in association with susceptibility to tuberculosis: a study in a Pakistani population

Tuberculosis is becoming a global issue with raising occurrences; particularly in developing countries, the situation is alarming. Besides environmental factors, host genetic factors are vital in disease development. A demographical and genotypic analysis in relation to tuberculosis commencement is conducted in a Pakistani population, and genotypic frequency of EBI3 (rs4740) was analyzed. Allelic frequencies of EBI3 (rs4740) were significantly associated with disease susceptibility in the reviewed population. Analysis for EBI3 (rs4740) genotyping showed a significant association of "GG" with reduced risk for disease. Moreover, females and older age found to be more perilous to develop TB while smoking and a family history of TB are additional risk factors for disease development. Further work with a larger population is necessary to identify the true causative variants of tuberculosis.

Nicotine, as a novel tolerogenic adjuvant, enhances the efficacy of immunotherapy in a mouse model of allergic asthma

An increasing trend in the incidence of allergic diseases including asthma and related morbidity and mortality is observed worldwide during the last decades. Allergen-specific immunotherapy is suggested for the treatment of some allergic diseases; nevertheless, there is always a menace of uncommon, but life-treating reactions due to increasing the administration of allergen extract doses. Hence, improving its efficacy may reduce the required doses as well as the risk of such reactions. The current study aimed at examining the effects of nicotine (NIC), as a tolerogenic adjuvant, on the improvement of immunotherapy efficacy in a mouse model of allergic asthma. BALB/c mice were sensitized using alum and ovalbumin (OVA) on the days 0 and 7. Mice received OVA either alone or together with NIC (1 or 10 mg/kg) on the days 21, 23, and 25. Then, the mice were challenged with OVA 5% using a nebulizer on the days 35, 38, and 41 and sacrificed the next day. Co-administration of OVA and NIC decreased the inflammation of the lung tissue, eosinophils count in the bronchoalveolar lavage (BAL) fluid, the serum level of OVA-specific immunoglobulin E, as well as interleukin (IL)-4 production, while increasing the population of antigen-specific regulatory T-cells (Treg cells) and transforming growth factor-β/IL-4 (TGF-β/IL-4) ratio compared to the OVA and control groups in a dose-dependent manner. Collectively, the findings suggest that administration of NIC plus the allergen increased immunotherapy efficacy through decreasing allergic inflammation and allergic responses intensity, and increasing Treg cells population.

Membrane transport status does not predict peritonitis risk in patients on peritoneal dialysis

AIM

The aim of this study is to determine whether peritoneal membrane transport status (MTS) is associated with peritonitis or poor peritoneal dialysis-related outcomes.

METHODS

This retrospective cohort study analysed data of incident adult patients on peritoneal dialysis in Western Sydney between 1 October 2003 and 31 December 2012. Only patients who underwent peritoneal equilibration and adequacy tests within 6 months of commencement were included. Kaplan-Meier survival curves for time until first peritonitis and time until composite endpoint of peritonitis, death or technique failure, censored for transplant, were constructed.

RESULTS

About 397 patients, mean age 58.8(+/-2SD29) years, body mass index (BMI) 26.6(+/-5) kg/m² and serum albumin 35.4(+/-5) g/L were included. About 59.2% had high/high-average peritoneal MTS; 45.8% were past and current smokers; 51.9% developed at least one episode of peritonitis; 7.6% changed to haemodialysis; 6.3% underwent transplantation; 8.8% died; and 25.4% remained free of the aforementioned events over a mean follow-up period of 22.5 months (range 0-115 months). Peritoneal MTS was not associated with time to first peritonitis (p = 0.67) or composite endpoint of peritonitis, death or technique failure (p = 0.12). Smoking and hypoalbuminaemia independently predicted time to first peritonitis. Past and current smokers had a hazard ratio of 1.38 (95% CI 1.03-1.86) for shorter time to first peritonitis, significant after adjustment for serum albumin (p = 0.033). Serum albumin <32 g/L had a hazard ratio of 1.74 (95% CI 1.13-2.67) for shorter time to first peritonitis, significant after adjusting for smoking (p = 0.012).

CONCLUSION

Smoking and hypoalbuminaemia, but not MTS, were associated with shorter time to first peritonitis and composite endpoint of peritonitis, death and technique failure.

Tobacco smoke and nicotine suppress expression of activating signaling molecules in human dendritic cells

Cigarette smoke has significant toxic effects on the immune system, and increases the risk of developing autoimmune diseases; one immunosuppressive effect of cigarette smoke is that it inhibits the T cell-stimulating, immunogenic properties of myeloid dendritic cells (DCs). As the functions of DCs are regulated by intra-cellular signaling pathways, we investigated the effects of cigarette smoke extract (CSE) and nicotine on multiple signaling molecules and other regulatory proteins in human DCs to elucidate the molecular basis of the inhibition of DC maturation and function by CSE and nicotine. Maturation of monocyte-derived DCs was induced with the TLR3-agonist poly I:C or with the TLR4-agonist lipopolysaccharide, in the absence or presence of CSE or nicotine. Reverse-phase protein microarray was used to quantify multiple signaling molecules and other proteins in cell lysates. Particularly in poly I:C-matured DCs, cigarette smoke constituents and nicotine suppressed the expression of signaling molecules associated with DC maturation and T cell stimulation, cell survival and cell migration. In conclusion, constituents of tobacco smoke suppress the immunogenic potential of DCs at the signaling pathway level.

Combination of TLR8 and TLR4 agonists reduces the degrading effects of nicotine on DC-NK mediated effector T cell generation

The magnitude of immune responses to vaccination is a critical factor in determining protection from disease. It is known that cigarette smoke dampens the immune system and increases the risk of vaccine-preventable diseases. We reported that nicotine, the immunosuppressive component of cigarette smoke, disrupts the differentiation and functional properties of DC, which are pivotal in the initiation of immune response to vaccines. We also reported that TLR agonists act in synergy and boost DC maturation, DC-NK crosstalk and ultimately naïve T cell polarization into effector Th1 and Tc1 cells. Here, we investigated whether the combination of TLR agonists could diminish the degrading effects of nicotine on DC-NK mediated effector T cell generation. We found that none of TLR agonists, single or combined, were able to diminish completely the adverse effects of nicotine on DC. However, TLR3, TLR4, and TLR8 agonists acted as the most effective adjuvants to increase the expression levels of antigen-presenting, costimulatory molecules and production of cytokines by nicotine-exposed DC (nicDC). When combined, TLR3 + 8 and TLR4 + 8 synergistically optimized nicDC maturation and IFN-γ secretion from nicotine-exposed NK (nicNK) during co-cultures. Interestingly, in contrast to DC-NK-T, co-cultures of nicDC-nicNK-T treated with TLR3 + 8 or TLR4 + 8 agonists produced a similar frequency of effector memory Th1 and Tc1 cells. However, the effector cells from TLR4 + 8 followed by TLR3 + 8 treated nicDC-nicNK-T co-cultures produced significantly more IFN-γ when compared with aluminum salt treated co-culture. Our data suggest that addition of appropriate TLR agonists to vaccine formulation could potentially augment the immune response to vaccination in smokers.

Tobacco Smoke Induces and Alters Immune Responses in the Lung Triggering Inflammation, Allergy, Asthma and Other Lung Diseases: A Mechanistic Review

Many studies have been undertaken to reveal how tobacco smoke skews immune responses contributing to the development of chronic obstructive pulmonary disease (COPD) and other lung diseases. Recently, environmental tobacco smoke (ETS) has been linked with asthma and allergic diseases in children. This review presents the most actual knowledge on exact molecular mechanisms responsible for the skewed inflammatory profile that aggravates inflammation, promotes infections, induces tissue damage, and may promote the development of allergy in individuals exposed to ETS. We demonstrate how the imbalance between oxidants and antioxidants resulting from exposure to tobacco smoke leads to oxidative stress, increased mucosal inflammation, and increased expression of inflammatory cytokines (such as interleukin (IL)-8, IL-6 and tumor necrosis factor α ([TNF]-α). Direct cellular effects of ETS on epithelial cells results in increased permeability, mucus overproduction, impaired mucociliary clearance, increased release of proinflammatory cytokines and chemokines, enhanced recruitment of macrophages and neutrophils and disturbed lymphocyte balance towards Th2. The plethora of presented phenomena fully justifies a restrictive policy aiming at limiting the domestic and public exposure to ETS.

Nicotine associated breast cancer in smokers is mediated through high level of EZH2 expression which can be reversed by methyltransferase inhibitor DZNepA

Recent studies show substantial growth-promoting properties of nicotine (NIC) in cancer, which is a combined outcome of genetic and epigenetic alterations. However, the role of epigenetic modifiers in response to NIC in breast cancer is less studied. In the present study, for the first time we have shown NIC-induced enhanced EZH2 expression. Six pairs of smoking-associated breast cancer patient tissues were analyzed. Samples from smoking breast cancer patients showed distinguished enhanced EZH2 expression in comparison to non-smoking ones. The upregulation in EZH2, which is due to NIC, was further confirmed in breast carcinoma cell lines using 10 µM NIC, 1 µM DZNepA, and EZH2si. The upregulation of EZH2 was concomitant with upregulation in Myc and α9-nAChR. The xenograft of breast cancer cells in BALB/c nude mice in the presence or absence of NIC showed significantly higher tumor uptake in the NIC injected group, which clearly demonstrates the effect of NIC in breast cancer progression. Interestingly, DZNepA considerably suppressed the NIC-mediated tumor growth. CHIP-qPCR assay confirmed the increased Myc enrichment on EZH2 promoter upon NIC treatment, thereby strengthening our findings that there exists an association between NIC, Myc, and EZH2. Overall, the present study identifies a strong association between NIC and EZH2 particularly in the progression of breast cancer in smokers through a novel axis involving nAChR and Myc. Moreover, the findings provide preliminary evidence suggesting potential of high level of EZH2 expression as a prognostic marker in smoking-associated breast cancer.

Cholinergic Modulation of Type 2 Immune Responses

In recent years, the bidirectional relationship between the nervous and immune system has become increasingly clear, and its role in both homeostasis and inflammation has been well documented over the years. Since the introduction of the cholinergic anti-inflammatory pathway, there has been an increased interest in parasympathetic regulation of both innate and adaptive immune responses, including T helper 2 responses. Increasing evidence has been emerging suggesting a role for the parasympathetic nervous system in the pathophysiology of allergic diseases, including allergic rhinitis, asthma, food allergy, and atopic dermatitis. In this review, we will highlight the role of cholinergic modulation by both nicotinic and muscarinic receptors in several key aspects of the allergic inflammatory response, including barrier function, innate and adaptive immune responses, and effector cells responses. A better understanding of these cholinergic processes mediating key aspects of type 2 immune disorders might lead to novel therapeutic approaches to treat allergic diseases.

Nicotine Impairs Macrophage Control of Mycobacterium tuberculosis

Pure nicotine impairs macrophage killing of Mycobacterium tuberculosis (MTB), but it is not known whether the nicotine component in cigarette smoke (CS) plays a role. Moreover, the mechanisms by which nicotine impairs macrophage immunity against MTB have not been explored. To neutralize the effects of nicotine in CS extract, we used a competitive inhibitor to the nicotinic acetylcholine receptor (nAChR)-mecamylamine-as well as macrophages derived from mice with genetic disruption of specific subunits of nAChR. We also determined whether nicotine impaired macrophage autophagy and whether nicotine-exposed T regulatory cells (Tregs) could subvert macrophage anti-MTB immunity. Mecamylamine reduced the CS extract increase in MTB burden by 43%. CS extract increase in MTB was also significantly attenuated in macrophages from mice with genetic disruption of either the α7, β2, or β4 subunit of nAChR. Nicotine inhibited autophagosome formation in MTB-infected THP-1 cells and primary murine alveolar macrophages, as well as increased the intracellular MTB burden. Nicotine increased migration of THP-1 cells, consistent with the increased number of macrophages found in the lungs of smokers. Nicotine induced Tregs to produce transforming growth factor-β. Naive mouse macrophages co-cultured with nicotine-exposed Tregs had significantly greater numbers of viable MTB recovered with increased IL-10 production and urea production, but no difference in secreted nitric oxide as compared with macrophages cocultured with unexposed Tregs. We conclude that nicotine in CS plays an important role in subverting macrophage control of MTB infection.

Maternal Smoking and Newborn Cytokine and Immunoglobulin Levels

INTRODUCTION

Prenatal smoking exposure may lead to permanent changes in neonatal inflammation and immune response that have lifelong implications, including increased risks for atopy and respiratory disorders.

METHODS

The effect of maternal smoking on neonatal biomarkers of inflammation and immune response was assessed among 3459 singletons and twins in the Upstate KIDS Study. The following inflammatory biomarkers were measured using newborn dried blood spots (DBSs): interleukin (IL)-1α, IL-1 receptor antagonist, IL-6, IL-8, C-reactive protein, and tumor necrosis factor alpha. Immunoglobulins (IgE, IgA, IgM, and IgG subclasses) were also assessed. We used generalized estimating equations to calculate mean differences (β) in biomarker levels by timing of pregnancy smoking, cigarette load, and secondhand smoke exposure after adjusting for sociodemographic and lifestyle factors including maternal body mass index.

RESULTS

Of the 344 (12%) women reporting smoking during pregnancy, about 40% continued throughout pregnancy and 13% reported smoking more than 1 pack per day. After covariate adjustment and Bonferroni correction for multiple comparisons, maternal smoking throughout pregnancy remained significantly associated with increased levels of IL-8 (β = 0.20, 95% confidence interval: 0.07, 0.32; p < .003). No significant associations were found with cigarette load or secondhand smoke exposure. Higher IgG3 levels were also associated with maternal smoking throughout pregnancy, although the association became nominally significant after adjustment for covariates (β = 0.09; 95% confidence interval: 0.0007, 0.17; p < .05).

CONCLUSIONS

Maternal smoking throughout pregnancy was independently associated with increased IL-8 levels in newborns. Importantly, neonates of women who stopped smoking anytime in pregnancy did not have increased IL-8 levels.

IMPLICATIONS

This study evaluated a range of inflammatory biomarkers and immunoglobulins in association with maternal smoking and timing/duration of smoking along with secondhand smoke exposure. By using DBSs, we present data from a large cohort of children born in Upstate New York. Our findings suggest that early differences in immunoregulation of neonates exposed to maternal smoking for full duration in utero may already be detected at birth.

Tuberculosis Infection: Occurrence and Risk Factors in Presumptive Tuberculosis Patients of the Serengeti Ecosystem in Tanzania

Background

Cross-species tuberculosis (TB) transmission between humans and animals has been reported for quite a long time in sub-Saharan Africa. Because humans and animals coexist in the same ecosystem, exploring their potential for cross-species transmission and the impact the disease may have on the health of humans, animals, and their products is critical.

Objectives

This study aimed to identify risk factors for transmission of TB (Mycobacterium tuberculosis) and to assess the potential for zoonotic TB (Mycobacterium bovis) transmission in the Serengeti ecosystem where humans and animals are in intense contact. Our aim is to create a base for future implementation of appropriate control strategies to limit infection in both humans and animals.

Methodology

We administered a semi-structured questionnaire to 421 self-reporting patients to gather information on risk factors and TB occurrence. In a parallel study, researchers screened sputum smears using Ziehl-Neelsen staining and confirmed by mycobacterial culture. We then performed descriptive statistics (Pearson's chi-square test) and logistic regression analysis to establish frequencies, association, and quantification of the risk factors associated with TB cases.

Results

Our findings showed 44% (95% confidence interval [CI], 0.40-0.49) of the results were positive from sputum samples collected over a 1-year duration in areas with a high TB burden, particularly the Bunda district, followed by the Serengeti and Ngorongoro districts. Of the culture-positive patients who also had infections other than TB (43/187 patients), 21 (49%) were HIV positive. Contact with livestock products (odds ratio [OR] 6.0; 95% CI, 1.81-19.9), infrequent milk consumption (OR 2.5; 95% CI, 1.42-4.23), cigarette smoking (OR 2.9; 95% CI, 1.19-7.1.2), and alcohol consumption (OR 2.3; 95% CI, 1.22-4.23) were associated with a higher likelihood of TB infection.

Conclusion

There was no evidence of direct cross-species transmission of either M tuberculosis or M bovis between humans and animals using the study methods. The absence of cross-species TB transmission could be due to limited chances of contact rather than an inability of cross-species disease transmission. In addition, not all people with presumptive TB are infected with TB, and therefore control strategies should emphasise confirming TB status before administering anti-TB drugs.

Standard radiotherapy but not chemotherapy impairs systemic immunity in non-small cell lung cancer

Introduction: Advanced non-small cell lung cancer (NSCLC) is traditionally treated with platinum-based chemotherapy and radiotherapy. Since immunotherapy holds promise for treating advanced NSCLC, we assessed the systemic effects of the traditional therapies for NSCLC on immune cell composition and function.

Methods: 84 pulmonary adenocarcinoma patients, treated either with chemotherapy or radiotherapy, were studied. A prospective study of 23 patients was conducted in which the myeloid and lymphoid cell compartments of peripheral blood were analyzed. Changes in cell populations were validated in a retrospective cohort of 61 adenocarcinoma patients using automated differential counts collected throughout therapy. Furthermore, the functional capacity of circulating T cells and antigen-presenting cells (APC) was studied. Blood samples of healthy individuals were used as controls.

Results: In comparison to healthy controls, untreated adenocarcinoma patients display an elevated frequency of myeloid cells coinciding with relative lower frequencies of lymphocytes and dendritic cells. Standard chemotherapy had no overt effects on myeloid and lymphoid cell composition nor on T-cell and APC-function. In contrast, patients treated with radiotherapy displayed a decrease in lymphoid cells and a relative increase in monocytes/macrophages. Importantly, these changes were associated with a reduced APC function and an impaired response of T cells to recall antigens.

Conclusions: Platinum-based standard of care chemotherapy for NSCLC has no profound negative effect on the immune cell composition and function. The negative effect of prolonged low-dose radiotherapy on the immune system warrants future studies on the optimal dose and fraction of radiotherapy when combined with immunotherapy.

Low IL-10/TNFα ratio in patients with coronary artery disease and reduced left ventricular ejection fraction with a poor prognosis after 10 years

Monocytes and dendritic cells (DC) produce tumour necrosis factor (TNF)α during inflammatory processes, but secrete interleukin (IL)-10 simultaneously in order to balance the pro-inflammation. In the present study, we investigated the expression of TNFα and IL-10 by monocytes and DC in patients with a poor cardiovascular prognosis after 10 years. Peripheral blood monocytes were isolated from 30 patients with coronary artery disease (CAD) with stable angina pectoris (SAP), or with an acute coronary syndrome (ACS). Monocytes were differentiated over 7 days to DC. Intracellular accumulation of TNFα and IL-10 in monocytes and DC was analysed by flow cytometry and correlated with the heart function, total and cardiovascular (CV) mortality, as well as with cardiovascular event rate over 10 years. We observed a decreased left ventricular function (LV-EF) for both SAP and ACS patients (p<0.01), as well as a reduced IL-10/TNFα ratio for monocytes (p=0.01) and DC (p<0.01) for both patient groups in comparison to age-matched control group. Only the IL-10/TNFα ratio for monocytes correlated with LV-EF (r=0.4302; p<0.01). Patients with a low LV-EF as well as patients with a low IL-10/TNFα ratio showed an increased cardiovascular mortality over 10 years (both p<0.05). The IL-10/TNFα ratio is decreased in patients with low ejection fraction and poor prognosis. The reduced heart function correlates with an increased proinflammatory state (low monocytic IL-10/TNFα ratio) in patients with CAD. This observed imbalance of IL-10 and TNFα in monocytes might explain pathophysiological processes in atherosclerosis and heart failure.

Excess TNF-α in the blood activates monocytes with the potential to directly form cholesteryl ester-laden cells

The tumor necrosis factor-α (TNF-α) and monocytic cells play a critical role in the development of atherosclerosis, which is the major cause of coronary heart disease (CHD). In this work, we investigated the effect of excess TNF-α on monocytes in the blood and found that blood monocytes from the CHD patients had the potential to directly form cholesteryl ester (CE)-laden cells under the in vitro incubation with oxLDL. The plasma levels of proinflammatory cytokines, such as TNF-α, interleukin 6 (IL-6), and C reactive protein (CRP), in the CHD patients were significantly higher than those in the control healthy volunteers. However, only the plasma level of TNF-α, but not of IL-6 or CRP, is positively correlated with the potential of blood monocytes to directly form CE-laden cells. By using human blood monocytes and monocytic THP-1 cells, the activating effect of TNF-α on the formation of the CE-laden cells was demonstrated, which could be specifically blocked by the anti-TNF-α antibody. Furthermore, it was also revealed that TNF-α could boost adhesion and oxLDL uptake of the monocytes by enhancing the expression of the functional adhesion molecules and scavenger receptors, respectively. Finally, the results of in vivo and in vitro experiments with a mouse model confirmed that excess TNF-α in the blood activates monocytes with the potential to directly form CE-laden cells. These data demonstrate that excess TNF-α in the blood is the primary trigger for the development of atherosclerosis and CHD.

Cigarette smoke differentially modulates dendritic cell maturation and function in time

Background

Dendritic cells (DCs) as professional antigen presenting cells (APCs) play a critical role in the regulation of host immune responses. DCs evolve from immature, antigen-capturing cells, to mature antigen-presenting cells. The relative contribution of DCs to cigarette smoke-induced inflammation is not well documented. In the current study, we investigated a modulatory effect of cigarette smoke extract (CSE) on differentiation, maturation and function of DCs.

Methods

Primary murine DCs were grown from bone marrow cells with GM-CSF. Development of DC was analyzed by expression of CD11c, MHCII, CD86, CD40 and CD83 using flow cytometry. Murine DC’s and human L428 cells were co-cultured with CSE for various periods of time. Functional activity was analyzed by measuring FITC-dextran uptake, cytokine production and the ability to stimulate T cell activation in a mixed lymphocyte reaction.

Results

Our results show that short-term CSE stimulation (~24 h) influence the maturation status of newly differentiated and immature DCs towards more mature cells as revealed by upregulation of MHCII, CD83, CD86, CD40, reduction in antigen up-take capacity and enhanced secretion of pro-inflammatory (IL-12, IL-6 and TNF-α) cytokines. Interestingly, long-term CSE exposure, time- and concentration-dependently, suppressed the development of functional DCs. This suppression was demonstrated by a decline in CD11c/MHCII, CD83, CD86 and CD40 expression, the production of cytokines and ability to stimulate T lymphocytes. Moreover, CSE significantly suppressed the endocytosis function of mouse DCs which was not due to diminished DC viability. Similar to mouse DCs, long-term co-culturing of the human L428 DC cell line with CSE time-dependently suppressed the expression of CD54.

Conclusions

The present study provides evidence that CSE modulates DC-mediated immune responses via affecting both the function and maturation of DCs. The suppressive effects of cigarette smoke on DC function might lead to impaired immune responses to various infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0291-6) contains supplementary material, which is available to authorized users.

Extracts from presumed "reduced harm" cigarettes induce equivalent or greater toxicity in antigen-presenting cells

The tobacco industry has promoted certain cigarette products with claims that their use may be less harmful to the smoker as they purportedly deliver lower amounts of toxic chemicals compared to conventional cigarettes. This study was designed to compare the relative antigen presenting cellular toxicity of Eclipse, a presumed reduced exposure product (PREP) cigarette, when compared with the reference research 3R4F cigarettes (Kentucky University). Utilizing a murine macrophage cell line, murine bone marrow derived dendritic cells (DCs) and human monocyte-derived DCs incubated with extracts generated from Eclipse and Kentucky reference 3R4F cigarettes, we determined the relative toxic effects of the different cigarette smoke extracts on cellular viability, oxidative stress, T-helper-1 (Th-1) polarizing cytokine production and general gene expression. Eclipse and 3R4F cigarette smoke extracts induced equivalent oxidatively-mediated cellular heme oxygenase-1 (HO-1) protein levels in macrophages and DCs. Cellular viability determination demonstrated greater induction of cell death by apoptosis and necrosis by Eclipse extracts in DCs. The production of the key Th-1 polarizing cytokine interleukin-12 (IL-12) by activated DCs or macrophages was suppressed to an equivalent or greater extent by Eclipse extracts. Microarray studies performed on bone marrow derived murine DCs incubated with Eclispe or 3R4F cigarette extracts showed identical genotoxic profiles. These studies imply that presumed reduced harm Eclipse cigarettes induce equivalent or greater antigen presenting cell dysfunction relative to 3R4F cigarettes and illustrate the importance of independent validation and testing of similar products claimed to be associated with reduced toxicity relative to other cigarettes.

Ameliorative effect of chronic moderate exercise in smoke exposed or nicotine applied rats from acute stress

INTRODUCTION

Physical activity has been found to be related with many health benefits. Our aim was to investigate the effect of chronic moderate exercise from acute stress on nicotine and cigarette smoke exposed rats.

METHODS

Male Sprague Dawley rats (200-250g, n = 48) were divided into 6 groups as non-exercised, exercised, smoke exposed, smoke exposed and exercised, nicotine applied, and nicotine applied and exercised. Nicotine bitartarate was applied intraperitoneally (0.1mg/kg/day) for 5 weeks, and cigarette smoke was exposed in a ventilated chamber. After 1 week of nicotine application or smoke exposure, moderate exercise training protocol was applied to exercise groups. At the end of the experiments, acute stress induction was made to all groups by electric foot shock. Holeboard tests were performed before and after the experiments. Biochemical and histological analyses were performed in lung, liver, colon, stomach, and gastrocnemius tissues.

RESULTS

Malondialdehyde levels were increased in all tissues of smoke exposed group (p < .05-.01) except gastrocnemius tissue compared to non-exercised group and were decreased with exercise (p < .05-.001). Myeloperoxidase levels were increased in lung, liver and colon tissues of smoke exposed group (p < .05-.001) and liver and colon tissues of nicotine applied rats (p < .01-.001) and decrease with exercise in liver and colon tissues of both smoke exposed or nicotine applied groups (p < .05-.01). In all tissue samples, increased histological injury scores (p < .05-.001) decreased significantly with exercise (p < .01-.001).

CONCLUSION

Biochemical parameters and histological scoring indicated increased tissue injury due to nicotine application and cigarette smoke exposure and exercise training ameliorated these effects in most of the tissues of acute stress induced rats.

Nicotine exposure alters the mRNA expression of Notch ligands in dendritic cells and their response to Th1-/Th2-promoting stimuli

Dendritic cells (DCs) utilize polarizing signals to instruct the differentiation of T helper (Th) cells into Th1 and Th2 effector cells: antigen-specific 'signal 1', costimulatory 'signal 2' and polarizing cytokines 'signal 3'. Accumulating evidence suggests the involvement of an additional signal, the Notch signalling pathway. We reported that in response to Th1-promoting stimuli, both mouse and human DCs generated in the presence of the immune modulator nicotine (nicDCs) fail to support the development of effector memory Th1 cells. However, in response to Th2-promoting stimuli, these nicDCs preferentially support the differentiation of antigen-specific IL-4-producing Th2 effector cells. Here, we show that when compared to their control counterparts, immature mouse and human nicDCs display higher levels of the Notch ligands D1, D4 and J2 mRNA expression. In response to Th1- and Th2-promoting stimuli, mouse nicDCs display higher levels of the Notch ligands D1, D4 and J2, while human nicDCs show higher levels of D1, D4 and J1 mRNA expression. Furthermore, both stimulated mouse and human nicDCs express higher CD86 to CD80 ratio and produce lower amount of IL-12. Collectively, our data suggest that these changes in addition to an increase in Jagged expression correlate with the ability of nicDCs to modulate the Th1/Th2 balance in favour of Th2 generation.