Chronic exposure to cigarette smoke increases matrix metalloproteinases and Filaggrin mRNA expression in oral keratinocytes: role of nicotine stimulation

The effect of long-term cigarette smoking on selected skin barrier proteins and lipids

The negative impact of cigarette smoking on the skin includes accelerated aging, pigmentation disorders, and impaired wound healing, but its effect on the skin barrier is not completely understood. Here, we studied the changes in selected epidermal proteins and lipids between smokers (45-66 years, smoking > 10 years, > 10 cigarettes per day) and non-smokers. Volar forearm epidermal and stratum corneum samples, obtained by suction blister and tape stripping, respectively, showed increased thickness in smokers. In the epidermis of smokers, we observed a significant upregulation of filaggrin, loricrin, and a trend of increased involucrin but no differences were found in the case of transglutaminase 1 and kallikrein-related peptidase 7, on the gene and protein levels. No significant changes were observed in the major skin barrier lipids, except for increased cholesterol sulfate in smokers. Liquid chromatography coupled with mass spectrometry revealed shorter acyl chains in ceramides, and an increased proportion of sphingosine and 6-hydroxysphingosine ceramides (with C4 trans-double bond) over dihydrosphingosine and phytosphingosine ceramides in smokers, suggesting altered desaturase 1 activity. Smokers had more ordered lipid chains found by infrared spectroscopy. In conclusion, cigarette smoking perturbs the homeostasis of the barrier proteins and lipids even at a site not directly exposed to smoke.

Immunohistochemical Expression of MMP-9, TIMP-1, and Vimentin and its Correlation With Inflammatory Reaction and Clinical Parameters in Oral Epithelial Dysplasia

The aim of this study was to investigate the immunoexpression of matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), and vimentin (VIM) and its association with the inflammatory reaction (IR) and clinical parameters in oral epithelial dysplasia (ED). The sample was composed of 66 cases of ED, 27 oral squamous cell carcinoma (OSCC), and 28 non-neoplastic epithelium (NNE). ED was graded according to the binary system as low-risk ED (n=42) and high-risk epithelial dysplasia (HRED: n=24). The IR was defined as the median number of inflammatory cells present on the connective tissue in 5 consecutive fields. Tissue sections of paraffin-embedded samples were immunohistochemically stained; MMP-9 and TIMP-1 expression was analyzed separately in the epithelium and the connective tissue; VIM was analyzed in the epithelium. Clinical parameters such as age, sex, lesion site and clinical presentation, alcohol/tobacco use, and malignant transformation of ED were retrospectively obtained from medical records. Nonhomogeneous leukoplakia presented higher odds (3.857; 95% confidence interval: 1.16-12.85) of being graded as HRED than did homogeneous lesions. The IR was higher in OSCC and ED than in NNE, and correlated with the epithelial expression of VIM. HRED and nonhomogeneous leukoplakias presented higher IR than did low-risk ED and homogeneous leukoplakias. Alcohol users had higher IR than nonalcohol users. Smokers had higher epithelial expression of MMP-9 and VIM. High IR in OSCC and HRED, and its positive correlation with VIM expression suggest a contribution of the IR in the progression of OSCC. Moreover, the high expression of MMP-9 and VIM in smokers implies its involvement in tobacco carcinogenesis.

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.

How Does Chronic Cigarette Smoke Exposure Affect Human Skin? A Global Proteomics Study in Primary Human Keratinocytes

Cigarette smoking has been associated with multiple negative effects on human skin. Long-term physiological effects of cigarette smoke are through chronic and not acute exposure. Molecular alterations due to chronic exposure to cigarette smoke remain unclear. Primary human skin keratinocytes chronically exposed to cigarette smoke condensate (CSC) showed a decreased wound-healing capacity with an increased expression of NRF2 and MMP9. Using quantitative proteomics, we identified 4728 proteins, of which 105 proteins were overexpressed (≥2-fold) and 41 proteins were downregulated (≤2-fold) in primary skin keratinocytes chronically exposed to CSC. We observed an alteration in the expression of several proteins involved in maintenance of epithelial barrier integrity, including keratin 80 (5.3 fold, p value 2.5 × 10-7), cystatin A (3.6-fold, p value 3.2 × 10-3), and periplakin (2.4-fold, p value 1.2 × 10-8). Increased expression of proteins associated with skin hydration, including caspase 14 (2.2-fold, p value 4.7 × 10-2) and filaggrin (3.6-fold, p value 5.4 × 10-7), was also observed. In addition, we report differential expression of several proteins, including adipogenesis regulatory factor (2.5-fold, p value 1.3 × 10-3) and histone H1.0 (2.5-fold, p value 6.3 × 10-3) that have not been reported earlier. Bioinformatics analyses demonstrated that proteins differentially expressed in response to CSC are largely related to oxidative stress, maintenance of skin integrity, and anti-inflammatory responses. Importantly, treatment with vitamin E, a widely used antioxidant, could partially rescue adverse effects of CSC exposure in primary skin keratinocytes. The utility of antioxidant-based new dermatological formulations in delaying or preventing skin aging and oxidative damages caused by chronic cigarette smoke exposure warrants further clinical investigations and multi-omics research.

Heavy Cigarette Smokers in a Chinese Population Display a Compromised Permeability Barrier

Cigarette smoking is associated with various cutaneous disorders with defective permeability. Yet, whether cigarette smoking influences epidermal permeability barrier function is largely unknown. Here, we measured skin biophysical properties, including permeability barrier homeostasis, stratum corneum (SC) integrity, SC hydration, skin surface pH, and skin melanin/erythema index, in cigarette smokers. A total of 99 male volunteers were enrolled in this study. Smokers were categorized as light-to-moderate (<20 cigarettes/day) or heavy smokers (≥20 cigarettes/day). An MPA5 was used to measure SC hydration and skin melanin/erythema index on the dorsal hand, forehead, and cheek. Basal transepidermal water loss (TEWL) and barrier recovery rates were assessed on the forearm. A Skin-pH-Meter pH900 was used to measure skin surface pH. Our results showed that heavy cigarette smokers exhibited delayed barrier recovery after acute abrogation (1.02% ± 13.06 versus 16.48% ± 6.07), and barrier recovery rates correlated negatively with the number of daily cigarettes consumption (p = 0.0087). Changes in biophysical parameters in cigarette smokers varied with body sites. In conclusion, heavy cigarette smokers display compromised permeability barrier homeostasis, which could contribute, in part, to the increased prevalence of certain cutaneous disorders characterized by defective permeability. Thus, improving epidermal permeability barrier should be considered for heavy cigarette smokers.

Nicotine stimulation increases proliferation and matrix metalloproteinases-2 and -28 expression in human dental pulp cells

AIMS

Dental pulp is the specialized tissue responsible for maintaining tooth viability. When tooth mineralized matrix is damaged, pulp is exposed to a plethora of environmental stimuli. In particular, in smokers, pulp become exposed to very high concentrations of nicotine. The aim of this study was to investigate the effect of direct nicotine stimulation on human dental pulp cell proliferation. Moreover, as it is known that nicotine could upregulate the expression of matrix metalloproteinases (MMPs), enzymes involved in pulpal inflammation, the effects of nicotine stimulation on MMP-2 and MMP-28 gene expression have also been investigated.

MAIN METHODS

Human dental pulp cells were extracted from impacted third molars obtained from healthy patients undergoing routine orthodontic treatments. Such cells were treated with growing concentrations of nicotine in the presence or absence of a nicotine antagonist (hexamethonium chloride) or of a MEK signaling inhibitor (PD98059). Cell proliferation was evaluated by cell counting, while nicotine effects on MMP expression were evaluated by PCR.

KEY FINDINGS

The data obtained indicate that nicotine is able to increase human dental pulp cell proliferation by acting through nicotinic cholinergic receptors and downstream MAPK signaling pathway. Moreover, it is also able to increase both MMP-2 and MMP-28 gene expression.

SIGNIFICANCE

In summary these results highlight that direct exposure of human dental pulp cells to nicotine results in an inflammatory response, that could have a role in pulpal inflammation onset, a pathological condition that, when ignored, could eventually spread to the surrounding alveolar bone and progress to pulp necrosis.

Periodontitis and Porphyromonas gingivalis in patients with rheumatoid arthritis

OBJECTIVE

To examine the degree to which shared risk factors explain the relationship of periodontitis (PD) to rheumatoid arthritis (RA) and to determine the associations of PD and Porphyromonas gingivalis with pathologic and clinical features of RA.

METHODS

Patients with RA (n = 287) and patients with osteoarthritis as disease controls (n = 330) underwent a standardized periodontal examination. The HLA-DRB1 status of all participants was imputed using single-nucleotide polymorphisms from the extended major histocompatibility complex. Circulating anti-P gingivalis antibodies were measured using an enzyme-linked immunosorbent assay, and subgingival plaque was assessed for the presence of P gingivalis using polymerase chain reaction (PCR). Associations of PD with RA were examined using multivariable regression.

RESULTS

Presence of PD was more common in patients with RA and patients with anti-citrullinated protein antibody (ACPA)-positive RA (n = 240; determined using the anti-cyclic citrullinated peptide 2 [anti-CCP-2] test) than in controls (35% and 37%, respectively, versus 26%; P = 0.022 and P = 0.006, respectively). There were no differences between RA patients and controls in the levels of anti-P gingivalis or the frequency of P gingivalis positivity by PCR. The anti-P gingivalis findings showed a weak, but statistically significant, association with the findings for both anti-CCP-2 (r = 0.14, P = 0.022) and rheumatoid factor (RF) (r = 0.19, P = 0.001). Presence of PD was associated with increased swollen joint counts (P = 0.004), greater disease activity according to the 28-joint Disease Activity Score using C-reactive protein level (P = 0.045), and higher total Sharp scores of radiographic damage (P = 0.015), as well as with the presence and levels of anti-CCP-2 (P = 0.011) and RF (P < 0.001). The expression levels of select ACPAs (including antibodies to citrullinated filaggrin) were higher in patients with subgingival P gingivalis and in those with higher levels of anti-P gingivalis antibodies, irrespective of smoking status. Associations of PD with established seropositive RA were independent of all covariates examined, including evidence of P gingivalis infection.

CONCLUSION

Both PD and P gingivalis appear to shape the autoreactivity of RA. In addition, these results demonstrate an independent relationship between PD and established seropositive RA.

Association between loss-of-function mutations in the filaggrin gene and self-reported food allergy and alcohol sensitivity

BACKGROUND

Loss-of-function mutations of the filaggrin (FLG) gene cause an impaired skin barrier and increase the risk of atopic dermatitis. Interestingly, FLG mutations have also been found to be associated with a high risk of peanut allergy.

OBJECTIVE

We investigated the association of FLG mutations with self-reported food allergy, symptoms of oral allergy syndrome (OAS), and alcohol sensitivity.

METHODS

A total of 3,471 adults from the general population participated in a health examination. Information on food allergies, OAS and alcohol sensitivity was obtained by questionnaire. FLG mutation carriers were defined as having at least one null mutation allele of R501X or 2282del4. Primary lactose intolerance (PLI) was defined as the C/C genotype of the rs4988235 polymorphism.

RESULTS

FLG mutations were associated with a higher risk of self-reported allergy to eggs (OR 3.22 and 95% CI 1.46-7.11), milk (OR 2.10 and 95% CI 1.12-3.92), fish (OR 4.54 and 95% CI 1.88-10.96) and wheat (OR 3.59 and 95% CI 1.61-8.02), but not with symptoms of OAS (OR 1.05 and 95% CI 0.73-1.51). Serum-specific IgE was measured in a subsample and confirmed the association between FLG and IgE to milk. A significant gene-by-gene interaction between FLG and PLI was observed in relation to self-reported allergy to milk. Furthermore, FLG mutations were associated with a higher risk of alcohol sensitivity.

CONCLUSIONS

We found that loss-of-function mutations in the FLG gene were significantly associated with self-reported food allergy and alcohol sensitivity, but not with OAS. These findings, if confirmed, support the idea that skin barrier functions may be involved in the pathogenesis of food allergy.

Interaction between filaggrin null mutations and tobacco smoking in relation to asthma

BACKGROUND

The mechanisms underlying the association between filaggrin (FLG) deficiency and asthma are not known. It has been hypothesized that FLG deficiency leads to enhanced percutaneous exposure to environmental substances that might trigger immune responses. We hypothesized that interactions between FLG deficiency and environmental exposures play a role in asthma development.

OBJECTIVE

We sought to investigate possible interactions between FLG null mutations and tobacco smoking in relation to asthma.

METHODS

A total of 3471 adults from a general population sample participated in a health examination. Lung function and serum specific IgE levels to inhalant allergens were measured, and information on asthma and smoking was obtained by means of questionnaire. Participants were genotyped for the 2 most common FLG null mutations in white subjects: R501X and 2282del4. Another Danish population was used for replication.

RESULTS

The FLG null mutation genotype was significantly associated with a higher prevalence of asthma and decreased FEV(1)/forced vital capacity ratio. In logistic regression analyses with asthma as the outcome, a significant interaction was found between FLG null mutations and smoking status (P = .02). This interaction was confirmed, although it was not statistically significant, in another Danish population study. Interactions between FLG genotype and cumulated smoking exposure were found in relation to asthma (P = .03) and decreased FEV(1)/forced vital capacity ratio (P = .03). A 3-way interaction was found among FLG genotype, smoking, and asthma, suggesting that the FLG-smoking interaction mainly played a role in nonatopic subjects.

CONCLUSION

FLG null mutations modified the effects of smoking on the risk of asthma. This finding might have implications for risk stratification of the population.