Water-pipe smoke condensate increases the internalization of Mycobacterium Bovis of type II alveolar epithelial cells (A549)

Endurance Exercise Training Attenuates the Waterpipe Smoke Inhaling-Induced Learning and Memory Impairment in Rats: Role of Neurotrophic Factors and Apoptotic System

INTRODUCTION

The increasing prevalence of waterpipe tobacco smoking (WTS) and its detrimental effects on memory function have been reported. This study was conducted to investigate the effect of moderate-intensity endurance exercise on the detrimental effects of WTS on learning and spatial memory in rats.

AIMS AND METHODS

Animals were divided into the Control group (CTL), the exercise group (Ex) which trained for 8 weeks, the WTS group (Wp) exposed to smoke inhalation (30 minutes per day, 5 days each week, and for 8 weeks), and the group that did exercise training and received waterpipe smoke together (Ex + Wp). Thereafter, learning and spatial memory were assessed by the Morris water maze test and hippocampal molecular measurements were done.

RESULTS

Waterpipe smoke significantly impaired learning and spatial memory, decreased expression of neurotrophic factors IGF-1 and BDNF (p < .01 and p < .05 vs. CTL group, respectively), increased BAX to BCL-2 ratio (p < .001 vs. CTL group) in hippocampal tissue, and increased the percent of damaged neurons in the hippocampal CA1 area (p < .05 vs. CTL group). Combination of exercise training with WTS prevented learning and spatial memory disturbances and recovered expression of neurotrophic factors IGF-1 (p < .05 vs. Wp group), decreased BAX to BCL-2 ratio (p < .001 vs. Wp group), and reduced percentage of damaged neurons (p < .05 vs. Wp group).

CONCLUSIONS

Findings suggest that moderate-intensity endurance exercise training can ameliorate learning and memory impairment caused by waterpipe smoke in rats. This effect partly results from increasing the expression of neurotrophic factors BDNF and IGF-1 and correcting pro/anti-apoptotic proteins balance in the hippocampal tissue.

IMPLICATIONS

The popularity of WTS especially among youth is increasing. We assessed the effect of hookah smoke with/without exercise on learning and memory. Hookah smoke leads to CA1-neural injury and impairs learning and memory in rats. A combination of exercise training with hookah smoke attenuates these complications. This positive effect of exercise is partially mediated by the balancing of brain-derived neurotrophic factor (BDNF) and Insulin-like growth factor-1 (IGF-1) and also the BAX to BCL-2 ratio, a significant predictor of cell susceptibility to apoptosis. Extrapolation of these positive findings to humans needs complementary studies.

Genomic Analysis of Waterpipe Smoke-Induced Lung Tumor Autophagy and Plasticity

The role of autophagy in lung cancer cells exposed to waterpipe smoke (WPS) is not known. Because of the important role of autophagy in tumor resistance and progression, we investigated its relationship with WP smoking. We first showed that WPS activated autophagy, as reflected by LC3 processing, in lung cancer cell lines. The autophagy response in smokers with lung adenocarcinoma, as compared to non-smokers with lung adenocarcinoma, was investigated further using the TCGA lung adenocarcinoma bulk RNA-seq dataset with the available patient metadata on smoking status. The results, based on a machine learning classification model using Random Forest, indicate that smokers have an increase in autophagy-activating genes. Comparative analysis of lung adenocarcinoma molecular signatures in affected patients with a long-term active exposure to smoke compared to non-smoker patients indicates a higher tumor mutational burden, a higher CD8+ T-cell level and a lower dysfunction level in smokers. While the expression of the checkpoint genes tested-PD-1, PD-L1, PD-L2 and CTLA-4-remains unchanged between smokers and non-smokers, B7-1, B7-2, IDO1 and CD200R1 were found to be higher in non-smokers than smokers. Because multiple factors in the tumor microenvironment dictate the success of immunotherapy, in addition to the expression of immune checkpoint genes, our analysis explains why patients who are smokers with lung adenocarcinoma respond better to immunotherapy, even though there are no relative differences in immune checkpoint genes in the two groups. Therefore, targeting autophagy in lung adenocarcinoma patients, in combination with checkpoint inhibitor-targeted therapies or chemotherapy, should be considered in smoker patients with lung adenocarcinoma.

The miR-196a SNP Rs11614913 but not the miR-499 rs37464444 SNP is a Risk Factor for Non-small Cell Lung Cancer in an Iranian Population

BACKGROUND

Globally, lung cancer represents a major cause of cancer-related deaths. The regulation of gene expression is modulated by small noncoding RNAs called miRNAs that can act as both tumor suppressors and oncogenes. The maturation, expression and binding to target mRNAs is affected by single nucleotide polymorphisms (SNPs) in miRNA genomic regions thereby contributing to cancer susceptibility. SNPs Rs11614913 in miR196a and Rs3746444 in miR-499 are implicated in the development of cancers such as non-small cell lung cancer (NSCLC) in non-Arabic subjects.

MATERIALS AND METHODS

A small cohort of 204 participants including 104 lung cancer patients and 100 non-cancer controls subjects were enrolled into the study. The allele frequencies were determined by Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) and their correlation with lung cancer risk was determined.

RESULTS

The miR-196a rs11614913 polymorphism increased the risk of NSCLC (CC vs. TT+TC: OR= 2.26, 95%CI= 1.28 - 3.98, P= 0.0046) in a dominant genetic model. No statistically significant association was found between the miR-499 rs37464444 polymorphism and NSCLC.

CONCLUSION

The rs11614913 polymorphism in miR-196a, but not the miR-499 rs37464444 polymorphism, increased the risk of NSCLC. Further studies with larger sample sizes in correlation with functional outcomes at the cellular level should be undertaken.

miR-4456/CCL3/CCR5 Pathway in the Pathogenesis of Tight Junction Impairment in Chronic Obstructive Pulmonary Disease

Background: Cigarette smoke exposure (CSE) is a major cause of chronic obstructive pulmonary disease (COPD). The smoke disrupts cell-cell adhesion by inducing epithelial barrier damage to the tight junction (TJ) proteins. Even though the inflammatory mechanism of chemokine (C-C motif) ligand 3 (CCL3) in COPD has gained increasing attention in the research community, however, the underlying signaling pathway, remains unknown.

Objectives: To identify the relationship of CCL3 in the pathogenesis of tight junction impairment in COPD and the pathway through which CSE causes damage to TJ in COPD via CCL3, both in vivo and in vitro.

Methods: We screened the inflammatory factors in the peripheral blood mononuclear cells (PBMCs) from healthy controls and patients at each GOLD 1-4 stage of chronic obstructive pulmonary disease. RT-PCR, western blot, and ELISA were used to detect the levels of CCL3, ZO-1, and occludin after Cigarette smoke exposure. Immunofluorescence was applied to examine the impairment of the TJs in 16-HBE and A549 cells. The reverse assay was used to detect the effect of a CCR5 antagonist (DAPTA) in COPD. In the CSE-induced COPD mouse model, H&E staining and lung function tests were used to evaluate the pathological and physical states in each group. Immunofluorescence was used to assess the impairment of TJs in each group. ELISA and RT-PCR were used to examine the mRNA or protein expression of CCL3 or miR-4456 in each group.

Results: The in vivo and in vitro results showed that CCL3 expression was increased in COPD compared with healthy controls. CCL3 caused significant injury to TJs through its C-C chemokine receptor type 5 (CCR5), while miR-4456 could suppress the effect of CCL3 on TJs by binding to the 3′-UTR of CCL3.

Conclusion: miR-4456/CCL3/CCR5 pathway may be a potential target pathway for the treatment of COPD.

The miR-146a SNP Rs2910164 and miR-155 SNP rs767649 Are Risk Factors for Non-Small Cell Lung Cancer in the Iranian Population

Background

Lung cancer is one of the leading causes of death worldwide. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression and may act as both tumor suppressors and as oncogenes. The presence of single nucleotide polymorphisms (SNPs) inside the miRNA genomic region could affect target miRNA maturation, expression, and binding to its target mRNA and contribute to cancer development. Previous studies on the SNPs Rs2910164 in miR-146a and Rs767649 in miR-155 showed association with non-small cell lung cancer (NSCLC) development. Thus, the aim of this study was to detect any correlation between those SNPs in Iranian NSCLC patients.

Methods

In a small cohort study, 165 NSCLC patients and 147 noncancer controls were enrolled between Apr 2015 and Sep 2019 at the Masih Daneshvari Hospital, Tehran, Iran. Allele frequencies from the genomic DNA of blood cells were studied using PCR-RFLP and their association with the risk of lung cancer was evaluated.

Results

The rs2910164C allele (OR = 1.56, 95% CI = 1.10–2.21, p = 0.012) and CC genotype (OR = 2.93, 95% CI = 1.07–7.9, p = 0.034, respectively) were associated with a significantly increased risk for lung cancer compared to that for the GG genotype. When patients were stratified according to smoking exposure, no association with rs2910164 variants was found. The AT genotype (OR = 0.57, 95% CI = 0.33–0.99, p = 0.048) and the A allele frequency (OR = 0.58, 95% CI = 0.35–0.98, p = 0.043) in rs767649 were lower in NSCLC patients in comparison with the control group. In addition, the rs767649 AT genotype frequency in smoking controls was higher than in smoking NSCLC patients (OR = 0.44, 95% CI = 0.21–0.90, p = 0.024). No association was found between rs2910164 and rs767649 variants and stage or type of NSCLC.

Conclusion

Our finding suggests that miR-146a rs2910164 and miR-155 rs767649 polymorphisms may be considered as genetic risk factors for the susceptibility to NSCLC in the Iranian population. However, a larger multicenter study across Iran is needed to confirm these findings.

MiRNAs in tuberculosis: Their decisive role in the fate of TB

Tuberculosis (TB) is one of the most lethal global infectious diseases. Despite the availability of much higher levels of technology in health and medicine, tuberculosis still remains a serious global health problem. Mycobacterium tuberculosis has the capacity for prolonged survival inside macrophages by exploiting host metabolic and energy pathways and perturbing autophagy and apoptosis of infected cells. The mechanism(s) underlying this process are not completely understood but evidence suggests that mycobacteria subvert the host miRNA network to enable mycobacterial survival. We present here a comprehensive review on the role of miRNAs in TB immune escape mechanisms and the potential for miRNA-based TB therapeutics. Further validation studies are required to (i) elucidate the precise effect of TB on host miRNAs, (ii) determine the inhibition of mycobacterial burden using miRNA-based therapies and (iii) identify novel miRNA biomarkers that may prove useful in TB diagnosis and treatment monitoring.

Water-pipe Smoking as a Risk Factor for Transmitting Mycobacterium tuberculosis

A 20-year-old Swiss male presented at the emergency department with acute onset of febrile temperatures and hemoptysis and a 3-month history of productive cough. An X-ray and CT scan of the chest, sputum samples for acid-fast bacilli, polymerase chain reaction(PCR), and cultures for Mycobacteria revealed pulmonary infection with Mycobacterium tuberculosis. None of the classical risk factors for tuberculosis were present, but the patient reported regularly smoking a water pipe. Water-pipe smoking poses a serious risk of M. tuberculosis transmission.

Membrane microdomains regulate NLRP10- and NLRP12-dependent signalling in A549 cells challenged with cigarette smoke extract

Chronic obstructive pulmonary disease (COPD) is predicted to become the third leading cause of death and disability worldwide by 2030; with cigarette smoking (active or passive) being one of the chief cause of its occurrence. Cigarette smoke exposure has been found to result in excessive inflammation and tissue injury, which might lead to COPD, although the exact pathophysiology of the disease remains elusive. While previous studies have demonstrated the role of membrane-bound Toll-like receptors (TLRs) in cigarette smoke (CS)-induced inflammation, scant information is available about the role of cytosolic NOD-like receptors (NLRs) in regulating CS-mediated inflammatory responses. Thus, we investigated the role of NLRP10 and NLRP12 in regulating inflammatory responses in human alveolar type II epithelial cells (A549) and human monocytic cells (THP-1) in response to a challenge with cigarette smoke extract (CSE). We observed CSE-mediated increase in caspase-1 activity; production of IL-1β and IL-18; and expression of NLRP10 and NLRP12 in A549 and THP-1 cells. Interestingly, immunofluorescence imaging results demonstrated an increase in the membrane recruitment of NLRP10 and NLRP12 proteins in CSE-challenged A549 cells. We also observed an increase in the expression of lipid raft proteins (caveolin-1, caveolin-2, and flotillin-1) and an induction of lipid raft assembly following CSE-exposure in A549 cells. Lipid rafts are cholesterol-rich membrane microdomains well known to act as harbours for signalling molecules. Here we demonstrate  the recruitment of NLRP10 and NLRP12 in lipid raft entities as well as the interaction of NLRP12 with the lipid raft protein caveolin-1 in CSE-challenged A549 cells. Furthermore, enrichment of lipid raft entities with poly-unsaturated fatty acids (PUFA) rescued A549 cells from CSE-mediated membrane recruitment of NLRP10 and NLRP12, and also from inflammatory responses and inflammasome activation. Enrichment of membrane microdomains with PUFA was able to reverse filipin (chemical agent used for disrupting lipid rafts)-mediated enhanced inflammation in CSE-challenged A549 cells. Overall, our findings unveil a novel mechanism by identifying an important role of membrane microdomains (lipid rafts) in regulating CSE-induced inflammation and NLRP10/NLRP12-dependent signalling in A549 cells.

Tuberculosis and cigarette smoke exposure: An update of in vitro and in vivo studies

Tuberculosis (TB) has been declared the first cause of death by an infectious agent. Annually, 10.4 million people suffer active TB. Most infected individuals live in low-income countries, where social and economic conditions enhance the dissemination and progression of the disease. These countries have a high percentage of smokers. Thousands of studies have linked cigarette smoke (CS) with increased risk of many diseases, such as cancer and lung diseases. Numerous in vitro studies have been conducted to evaluate the general and specific toxic effects of CS in lung immune function. Smoke exposure increases the risk of TB development three-fold. However, until now, only few animal studies have been performed to analyze the association between smoke and TB. In the present work, we review in vitro and in vivo studies whose aim was to analyze the molecular basis of TB susceptibility caused by exposure to CS.

Cigarette smoke-induced inflammation: NLRP10-mediated mechanisms

Chronic obstructive pulmonary disease (COPD) is a progressive, life-threatening disease that causes irreversible lung damage. Cigarette smoking is the chief etiologic factor for the commencement of this condition. Despite constant efforts to develop therapeutic interventions and to ascertain the molecular mechanism leading to the pathophysiology of this disease, much remains unknown. However, pattern recognition receptors (PRRs), i.e., Toll-like-receptors (TLRs) and NOD-like receptors (NLRs) are believed to play important roles in COPD and could serve as effective therapeutic targets. Although the role of TLRs in COPD has been well studied, the importance of NLRs has not yet been explored in detail. The NLR family member NLRP10 (aka NOD8, PAN5, PYNOD) is the only member of this family of proteins that lacks the leucine rich repeat (LRR) domain responsible for detection of pathogen and danger-associated molecular patterns (PAMPs/DAMPs). Therefore, instead of functioning as a PRR, NLRP10 may have a broader regulatory role. To elucidate the role of NLRP10 in secondhand smoke (SHS)-induced inflammation, we exposed C57Bl/6 (WT) and Nlrp10-deficient mice (Nlrp10^-/-) on the C57Bl/6 background to filtered air- or SHS- for 6 weeks (acute exposure) and assessed the resulting molecular events. Leukocyte recruitment in SHS-exposed Nlrp10^-/- mice was found to be significantly lower compared to SHS-exposed WT mice. In addition, we observed an important role for NLRP10 in SHS-mediated caspase-1 activation, cytokine/chemokine production (IL-1β, IL-18, MCP-1 and IL-17A), and induction of NF-κB and MAPKs in the lungs of C57Bl/6 mice. The reduced influx of CD4⁺IL-17A⁺ and CD8⁺IL-17A⁺ cells into the lungs of SHS-exposed Nlrp10^-/- mice and impaired differentiation of Nlrp10^-/- Th0 cells into Th17 cells (ex vivo) provide insight into the mechanistic details underlying NLRP10-dependent IL-17 production. We further substantiated our in vivo findings by challenging human alveolar type II epithelial cells (A549) transfected with scrambled- or Nlrp10-siRNA with cigarette smoke extract (CSE). We observed an important role of NLRP10 in cytokine and chemokine production as well as expression of NF-κB and MAPKs in CSE-exposed A549 cells. Furthermore, replenishment of A549 cell culture with recombinant IL-17A (rIL-17A) during NLRP10 knockdown rescued CSE-induced inflammatory responses. To identify upstream mediators of NLRP10 regulation we investigated epigenetic markers within the Nlrp10 promoter following cigarette smoke exposure and observed significant changes in active as well as repressive gene markers on histone 3 and histone 4 using both in vivo and in vitro study models. Further, alterations in the respective histone acetyl- and methyltransferases (PCAF, SET1, ESET, SUV20H1) correlated well with the observed histone modifications. Overall, our findings suggest a novel role of epigenetically regulated NLRP10 in Th17/IL-17 signaling during CS exposure.