Epigenetics mediate environment : gene effects on occupational sensitization

Impact of climate change on immune responses and barrier defense

Climate change is not just jeopardizing the health of our planet but is also increasingly affecting our immune health. There is an expanding body of evidence that climate-related exposures such as air pollution, heat, wildfires, extreme weather events, and biodiversity loss significantly disrupt the functioning of the human immune system. These exposures manifest in a broad range of stimuli, including antigens, allergens, heat stress, pollutants, microbiota changes, and other toxic substances. Such exposures pose a direct and indirect threat to our body's primary line of defense, the epithelial barrier, affecting its physical integrity and functional efficacy. Furthermore, these climate-related environmental stressors can hyperstimulate the innate immune system and influence adaptive immunity-notably, in terms of developing and preserving immune tolerance. The loss or failure of immune tolerance can instigate a wide spectrum of noncommunicable diseases such as autoimmune conditions, allergy, respiratory illnesses, metabolic diseases, obesity, and others. As new evidence unfolds, there is a need for additional research in climate change and immunology that covers diverse environments in different global settings and uses modern biologic and epidemiologic tools.

LncRNAs ENST00000499459 and TCONS_00004989 enhance asthma progression in children with house dust mite-induced allergic asthma

BACKGROUND

Long non-coding RNAs (lncRNAs) have been extensively reported to play critical roles in the pathogenesis of various disease, especially in cancer. However, little is known about the role of lncRNAs in the pathogenesis of pediatric allergic asthma.

METHODS

High-throughput sequencing analysis was performed to identify differentially expressed mRNAs and lncRNAs in peripheral blood mononuclear cells (PBMCs) from 3 children with allergic asthma and 3 matched healthy controls. Bioinformatics analysis was used to select candidate lncRNAs and mRNAs that may be involved in the pathogenesis of asthma. Candidate lncRNAs were validated in a larger size of asthma patients and healthy controls. Finally, lncRNAs and molecular pathways associated with the pathogenesis of allergic asthma were identified by competing endogenous RNA (ceRNA) analysis.

RESULTS

Five differentially expressed lncRNAs were identified after high-throughput sequencing and verified by real-time PCR. LncRNAs ENST0000631797, TCONS_00004989 and ENST00000499459 were verified to be differentially expressed in allergic asthma. Besides, ENST00000499459/DIXDC1 axis was identified to play a crucial role in allergic asthma after comprehensive ceRNA network analysis.

CONCLUSION

ENST00000499459 and TCONS_00004989 are potential biomarkers for house dust mite-induced allergic asthma.

Benzo[a]pyrene immunogenetics and immune archetype reprogramming of lung

Overexposure to carcinogenic precursor, benzo[a]pyrene [BaP], modulates the lung immune microenvironment. The present review seeks to elucidate novel pathways behind the tumor effect of BaP in the lungs, emphasizing immunomodulatory mediators and immune cells. In this review, BaP reprograms lung immune microenvironment through modulating transforming growth factor-beta (TGF-β), programmed cell death 1 (PD-1), cytotoxic T lymphocyte antigen-4 (CTLA-4), Interleukin 12 (IL-12), indoleamine 2,3 dioxygenase (IDO), forkhead box protein P3 (FOXP3) and interferon-gamma (IFN-γ) levels. Moreover, BaP modulated lung immune cellular architecture such as dendritic cells, T cells, Tregs, macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs). All mentioned changes in immune architecture and mediators lead to the induction of lung cancer.

Surface Topography of Titanium Affects Their Osteogenic Potential through DNA Methylation

It is widely accepted that sandblasted/large-grit/acid-etched (SLA) surfaces of titanium (Ti) have a higher osteogenic potential than machined ones. However, most studies focused on differential gene expression without elucidating the underlying mechanism for this difference. The aim of this study was to evaluate how the surface roughness of dental Ti implants affects their osteogenic potential. Mouse preosteoblast MC3T3-E1 cells were seeded on machined and SLA Ti discs. The cellular activities of the discs were analyzed using confocal laser scanning microscopy, proliferation assays, and real-time polymerase chain reaction (PCR). DNA methylation was evaluated using a methylation-specific PCR. The cell morphology was slightly different between the two types of surfaces. While cellular proliferation was slightly greater on the machined surfaces, the osteogenic response of the SLA surfaces was superior, and they showed increased alkaline phosphatase (Alp) activity and higher bone marker gene expression levels (Type I collagen, Alp, and osteocalcin). The degree of DNA methylation on the Alp gene was lower on the SLA surfaces than on the machined surfaces. DNA methyltransferase inhibitor stimulated the Alp gene expression on the machined surfaces, similar to the SLA surfaces. The superior osteogenic potential of the SLA surfaces can be attributed to a different epigenetic landscape, specifically, the DNA methylation of Alp genes. This finding offers novel insights into epigenetics to supplement genetics and raises the possibility of using epidrugs as potential therapeutic targets to enhance osteogenesis on implant surfaces.

Air pollution associated epigenetic modifications: Transgenerational inheritance and underlying molecular mechanisms

Air pollution is one of the leading causes of deaths in Southeast Asian countries including India. Exposure to air pollutants affects vital cellular mechanisms and is intimately linked with the etiology of a number of chronic diseases. Earlier work from our laboratory has shown that airborne particulate matter disturbs the mitochondrial machinery and causes significant damage to the epigenome. Mitochondrial reactive oxygen species possess the ability to trigger redox-sensitive signaling mechanisms and induce irreversible epigenomic changes. The electrophilic nature of reactive metabolites can directly result in deprotonation of cytosine at C-5 position or interfere with the DNA methyltransferases activity to cause alterations in DNA methylation. In addition, it also perturbs level of cellular metabolites critically involved in different epigenetic processes like acetylation and methylation of histone code and DNA hypo or hypermethylation. Interestingly, these modifications may persist through downstream generations and result in the transgenerational epigenomic inheritance. This phenomenon of subsequent transfer of epigenetic modifications is mainly associated with the germ cells and relies on the germline stability of the epigenetic states. Overall, the recent literature supports, and arguably strengthens, the contention that air pollution might contribute to transmission of epimutations from gametes to zygotes by involving mitochondrial DNA, parental allele imprinting, histone withholding and non-coding RNAs. However, larger prospective studies using innovative, integrated epigenome-wide metabolomic strategy are highly warranted to assess the air pollution induced transgenerational epigenetic inheritance and associated human health effects.

Dysregulated Expression of Long Intergenic Non-coding RNAs (LincRNAs) in Urothelial Bladder Carcinoma

Long intergenic non-coding RNA (lincRNA) has been introduced as key regulators of diverse biological processes, including transcription, chromatin organization, cell growth and tumorigenesis. With regard to the potential role of lincRNAs in cancer development, one may postulate that differential expression of lincRNAs could be employed as a tool in cancer diagnosis, prognosis, and targeted therapy. In this study, we aimed to explore the putative correlation between the expression levels of two lincRNAs: LINC00152 and LINC01082 in the bladder cancer (BC), in comparison with its adjacent non-cancerous tissue. Fifty Iranian subjects diagnosed with BC, representing in different stages and grades participated in this study The mRNA expression levels of the abovementioned lincRNAs were comparatively analyzed in cancerous and their adjacent non-cancerous counterpart tissues, of each subject by Real-Time PCR. The expression levels of LINC00152, and LINC01082 were significantly lower in tumor tissues in comparison with their adjacent normal tissues (P<0.001). More notably, in the case of LINC01082 the reduced expression was differentiated by the muscle invasiveness pattern of the tumor (P= 0.05). Our study presents a new finding about the tumor suppressor potentiality of these lincRNAs in BC development that in turn may suggest them as candidate biomarkers. Replicating this study in higher number of BC subjects, coupled with functional analysis, is necessary to investigate interconnections between these RNAs and cancer development, leading to better understanding of cancer biology.

Leveraging gene-environment interactions and endotypes for asthma gene discovery

Asthma is a heterogeneous clinical syndrome that includes subtypes of disease with different underlying causes and disease mechanisms. Asthma is caused by a complex interaction between genes and environmental exposures; early-life exposures in particular play an important role. Asthma is also heritable, and a number of susceptibility variants have been discovered in genome-wide association studies, although the known risk alleles explain only a small proportion of the heritability. In this review, we present evidence supporting the hypothesis that focusing on more specific asthma phenotypes, such as childhood asthma with severe exacerbations, and on relevant exposures that are involved in gene-environment interactions (GEIs), such as rhinovirus infections, will improve detection of asthma genes and our understanding of the underlying mechanisms. We will discuss the challenges of considering GEIs and the advantages of studying responses to asthma-associated exposures in clinical birth cohorts, as well as in cell models of GEIs, to dissect the context-specific nature of genotypic risks, to prioritize variants in genome-wide association studies, and to identify pathways involved in pathogenesis in subgroups of patients. We propose that such approaches, in spite of their many challenges, present great opportunities for better understanding of asthma pathogenesis and heterogeneity and, ultimately, for improving prevention and treatment of disease.

[Genetic and immune-toxicologic studies on abnormal thyroid functions in hospital employees exposed to cytostatic drugs]

INTRODUCTION

Environmental exposure to harmful chemicals may produce severe consequences.

AIM

The aim of the authors was to perform geno- and immune-toxicological monitoring in female employees occupationally exposed to cytostatic agents in hospitals and compare the findings to those obtained from controls.

METHOD

Altogether 642 women working in hospital who were occupationally exposed to cytostatic drugs and 262 control women participated in the study. Frequency of chromosome aberrations, immune phenotype and activation of lymphocytes, and the production of reactive oxygen-species in neutrophil granulocytes were determined.

RESULTS

Markedly higher number (n=39) of thyroid alterations was observed among exposed subjects as compared to controls (n=3). In persons with abnormal thyroid functions, the frequency of chromosome aberrations (3.69%) was significantly higher (3.69%) than in exposed subjects without thyroid alterations (2.43%) and in controls (1.70% and 1.60% in control subjects with and without thyroid alterations, respectively). Significantly increased ratio of helper T lymphocytes and decreased ratio of cytotoxic T cells and transferrin-receptor (CD71) expressing B cells were observed in exposed subjects having abnormal thyroid functions as compared to controls. In addition, the ratio of B cells, CD71 expressing T cells and production of reactive oxygen-intermediates was significantly decreased in exposed subjects with thyroid alterations in comparison to exposed subjects without thyroid alterations.

CONCLUSIONS

The results indicate increased geno- and immune-toxic effects among exposed subjects having thyroid alterations. Further data are needed to clearly establish the underlying pathophysiological mechanism of this finding.

Epigenomics and allergic disease

Allergic disease development is affected by both genes and the environment, and epigenetic mechanisms are hypothesized to mediate these environmental effects. In this article, we discuss the link between the environment, DNA methylation and allergic disease, as well as questions of causality inherent to analyses of DNA methylation. From the practical side, we describe characteristics of allergic phenotypes and contrast different epidemiologic study designs used in epigenetic research. We examine methodological considerations, how best to conduct preprocessing and analysis of DNA methylation data sets, and the latest methods, technologies and discoveries in this rapidly advancing field. DNA methylation and other epigenetic marks are firmly entwined with allergic disease, a link that may hold the basis for future allergic disease diagnosis and treatment.

Pulmonary oxidative stress, inflammation and cancer: respirable particulate matter, fibrous dusts and ozone as major causes of lung carcinogenesis through reactive oxygen species mechanisms

Reactive oxygen or nitrogen species (ROS, RNS) and oxidative stress in the respiratory system increase the production of mediators of pulmonary inflammation and initiate or promote mechanisms of carcinogenesis. The lungs are exposed daily to oxidants generated either endogenously or exogenously (air pollutants, cigarette smoke, etc.). Cells in aerobic organisms are protected against oxidative damage by enzymatic and non-enzymatic antioxidant systems. Recent epidemiologic investigations have shown associations between increased incidence of respiratory diseases and lung cancer from exposure to low levels of various forms of respirable fibers and particulate matter (PM), at occupational or urban air polluting environments. Lung cancer increases substantially for tobacco smokers due to the synergistic effects in the generation of ROS, leading to oxidative stress and inflammation with high DNA damage potential. Physical and chemical characteristics of particles (size, transition metal content, speciation, stable free radicals, etc.) play an important role in oxidative stress. In turn, oxidative stress initiates the synthesis of mediators of pulmonary inflammation in lung epithelial cells and initiation of carcinogenic mechanisms. Inhalable quartz, metal powders, mineral asbestos fibers, ozone, soot from gasoline and diesel engines, tobacco smoke and PM from ambient air pollution (PM₁₀ and PM₂.₅) are involved in various oxidative stress mechanisms. Pulmonary cancer initiation and promotion has been linked to a series of biochemical pathways of oxidative stress, DNA oxidative damage, macrophage stimulation, telomere shortening, modulation of gene expression and activation of transcription factors with important role in carcinogenesis. In this review we are presenting the role of ROS and oxidative stress in the production of mediators of pulmonary inflammation and mechanisms of carcinogenesis.

Recent advances in particulate matter and nanoparticle toxicology: a review of the in vivo and in vitro studies

Epidemiological and clinical studies have linked exposure to particulate matter (PM) to adverse health effects, which may be registered as increased mortality and morbidity from various cardiopulmonary diseases. Despite the evidence relating PM to health effects, the physiological, cellular, and molecular mechanisms causing such effects are still not fully characterized. Two main approaches are used to elucidate the mechanisms of toxicity. One is the use of in vivo experimental models, where various effects of PM on respiratory, cardiovascular, and nervous systems can be evaluated. To more closely examine the molecular and cellular mechanisms behind the different physiological effects, the use of various in vitro models has proven to be valuable. In the present review, we discuss the current advances on the toxicology of particulate matter and nanoparticles based on these techniques.

Testing the nanoparticle-allostatic cross-adaptation-sensitization model for homeopathic remedy effects

Key concepts of the Nanoparticle-Allostatic Cross-Adaptation-Sensitization (NPCAS) Model for the action of homeopathic remedies in living systems include source nanoparticles as low level environmental stressors, heterotypic hormesis, cross-adaptation, allostasis (stress response network), time-dependent sensitization with endogenous amplification and bidirectional change, and self-organizing complex adaptive systems. The model accommodates the requirement for measurable physical agents in the remedy (source nanoparticles and/or source adsorbed to silica nanoparticles). Hormetic adaptive responses in the organism, triggered by nanoparticles; bipolar, metaplastic change, dependent on the history of the organism. Clinical matching of the patient's symptom picture, including modalities, to the symptom pattern that the source material can cause (cross-adaptation and cross-sensitization). Evidence for nanoparticle-related quantum macro-entanglement in homeopathic pathogenetic trials. This paper examines research implications of the model, discussing the following hypotheses: Variability in nanoparticle size, morphology, and aggregation affects remedy properties and reproducibility of findings. Homeopathic remedies modulate adaptive allostatic responses, with multiple dynamic short- and long-term effects. Simillimum remedy nanoparticles, as novel mild stressors corresponding to the organism's dysfunction initiate time-dependent cross-sensitization, reversing the direction of dysfunctional reactivity to environmental stressors. The NPCAS model suggests a way forward for systematic research on homeopathy. The central proposition is that homeopathic treatment is a form of nanomedicine acting by modulation of endogenous adaptation and metaplastic amplification processes in the organism to enhance long-term systemic resilience and health.

Maternal predictors of intrauterine growth restriction

PURPOSE OF REVIEW

Intrauterine growth restriction (IUGR) occurs when fetal growth rate falls below the genetic potential and affects a significant number of pregnancies, but still no therapy has been developed for this pregnancy disease. This article reviews the most recent findings concerning maternal characteristics and behaviours predisposing to IUGR as well as maternal early markers of the disease. A comprehensive understanding of factors associated with IUGR will help in providing important tools for preventing and understanding adverse outcomes.

RECENT FINDINGS

Maternal nutritional status, diet and exposure to environmental factors are increasingly acknowledged as potential factors affecting fetal growth both by altering nutrient availability to the fetus and by modulating placental gene expression, thus modifying placental function.

SUMMARY

Assessing nutritional and environmental factors associated with IUGR, and the molecular mechanisms by which they may have a role in the disease onset, is necessary to provide comprehensive and common guidelines for maternal care and recommended behaviours. Moreover, maternal genetic predispositions and early serum markers may allow a better and more specific monitoring of high risk pregnancies, optimizing the timing of delivery.

Cytokine levels in gestational diabetes mellitus: a systematic review of the literature

PROBLEM

Gestational diabetes mellitus (GDM) is an inflammatory condition that involves unbalanced cytokine production. We carried out a systematic review on the relationship between GDM and maternal circulating levels of cytokines in the 2nd/3rd trimesters.

METHOD OF STUDY

Three electronic databases (MEDLINE, EMBASE and LILACS), were searched. Duplicate study selection, extraction and quality assessment was performed.

RESULTS

Twenty-two studies with 1982 participants reporting levels of 9 cytokines (IL-1B, IL-2, IL-6, IL-10, IL-13, IL-18, IFN-G, TGF-B and TNF-A) were included. Most studies differed considerably in selection criteria, sampling and assay methods and in reporting their results. Consequently, only two studies could be pooled: TNF-A concentration was slightly higher in GDM than in control patients, although not significant (WMD=0.45, 95% CI -0.34-1.23).

CONCLUSIONS

New studies with well-defined, more homogeneous methodological parameters are needed to detect whether there are significant differences in circulating levels of cytokines in patients with GDM.

Secondhand smoke in combination with ambient air pollution exposure is associated with increasedx CpG methylation and decreased expression of IFN-γ in T effector cells and Foxp3 in T regulatory cells in children

BACKGROUND

Secondhand smoke (SHS) and ambient air pollution (AAP) exposures have been associated with increased prevalence and severity of asthma and DNA modifications of immune cells. In the current study, we examined the association between SHS and AAP with DNA methylation and expression of interferon-gamma (IFN-γ) and forkhead box protein 3 (Foxp3) in T cell populations.

METHODS

Subjects 7-18 years old were recruited from Fresno (high AAP; n = 62) and Stanford, CA (low AAP; n = 40) and divided into SHS-exposed (Fresno: n = 31, Stanford: n = 6) and non-SHS-exposed (nSHS; Fresno: n = 31, Stanford: n = 34) groups. T cells purified from peripheral blood were assessed for levels of DNA methylation and expression of IFN-γ (in effector T cells) or Foxp3 (in regulatory T cells).

RESULTS

Analysis showed a significant increase in mean % CpG methylation of IFN-γ and Foxp3 associated with SHS exposure (IFN-γ: FSHS 62.10%, FnSHS 41.29%, p < 0.05; SSHS 46.67%, SnSHS 24.85%, p < 0.05; Foxp3: FSHS 74.60%, FnSHS 54.44%, p < 0.05; SSHS 62.40%, SnSHS 18.41%, p < 0.05) and a significant decrease in mean transcription levels of both genes (IFN-γ: FSHS 0.75, FnSHS 1.52, p < 0.05; SHS 2.25, nSHS 3.53, p < 0.05; Foxp3: FSHS 0.75, FnSHS 3.29, p < 0.05; SSHS 4.8, SnSHS 7.2, p < 0.05). AAP was also associated with hypermethylation (IFN-γ: FSHS vs. SSHS, p < 0.05; FnSHS vs. SnSHS, p < 0.05; Foxp3: FSHS vs. SSHS, p < 0.05; FnSHS vs. SnSHS, p < 0.05) and decreased transcription of both genes (IFN-γ: FSHS vs. SSHS, p < 0.05; FnSHS vs. SnSHS, p < 0.05; Foxp3: FSHS vs. SSHS, p < 0.05; FnSHS vs. SnSHS, p < 0.05). Average methylation between AAP- and SHS-only exposures was not significantly different (IFN-γ: p = 0.15; Foxp3: p = 0.27), nor was Foxp3 expression (p = 0.08); IFN-γ expression was significantly decreased in AAP-only subjects (p < 0.05).

CONCLUSIONS

Exposures to SHS and AAP are associated with significant hypermethylation and decreased expression of IFN-γ in Teffs and Foxp3 in Tregs. Relative contributions of each exposure to DNA modification and asthma pathogenesis warrant further investigation.