The interaction between environmental triggers and epigenetics in autoimmunity

Increasing Specificity of Targeted DNA Methylation Editing by Non-Enzymatic CRISPR/dCas9-Based Steric Hindrance

As advances in genome engineering inch the technology towards wider clinical use-slowed by technical and ethical hurdles-a newer offshoot, termed "epigenome engineering", offers the ability to correct disease-causing changes in the DNA without changing its sequence and, thus, without some of the unfavorable correlates of doing so. In this review, we note some of the shortcomings of epigenetic editing technology-specifically the risks involved in the introduction of epigenetic enzymes-and highlight an alternative epigenetic editing strategy using physical occlusion to modify epigenetic marks at target sites without a requirement for any epigenetic enzyme. This may prove to be a safer alternative for more specific epigenetic editing.

Consensus on the Key Characteristics of Immunotoxic Agents as a Basis for Hazard Identification

BACKGROUND

Key characteristics (KCs), properties of agents or exposures that confer potential hazard, have been developed for carcinogens and other toxicant classes. KCs have been used in the systematic assessment of hazards and to identify assay and data gaps that limit screening and risk assessment. Many of the mechanisms through which pharmaceuticals and occupational or environmental agents modulate immune function are well recognized. Thus KCs could be identified for immunoactive substances and applied to improve hazard assessment of immunodulatory agents.

OBJECTIVES

The goal was to generate a consensus-based synthesis of scientific evidence describing the KCs of agents known to cause immunotoxicity and potential applications, such as assays to measure the KCs.

METHODS

A committee of 18 experts with diverse specialties identified 10 KCs of immunotoxic agents, namely, 1) covalently binds to proteins to form novel antigens, 2) affects antigen processing and presentation, 3) alters immune cell signaling, 4) alters immune cell proliferation, 5) modifies cellular differentiation, 6) alters immune cell-cell communication, 7) alters effector function of specific cell types, 8) alters immune cell trafficking, 9) alters cell death processes, and 10) breaks down immune tolerance. The group considered how these KCs could influence immune processes and contribute to hypersensitivity, inappropriate enhancement, immunosuppression, or autoimmunity.

DISCUSSION

KCs can be used to improve efforts to identify agents that cause immunotoxicity via one or more mechanisms, to develop better testing and biomarker approaches to evaluate immunotoxicity, and to enable a more comprehensive and mechanistic understanding of adverse effects of exposures on the immune system. https://doi.org/10.1289/EHP10800.

An overview of the relationship between juvenile idiopathic arthritis and potential environmental risk factors: Do early childhood habits or habitat play a role in the affair?

AIM

The current study was undertaken to evaluate the influence of breastfeeding on the development and outcome measures of juvenile idiopathic arthritis (JIA). The second aim was to determine the consequences of particular sociodemographic and sociocultural characteristics and nutritional behavior of early childhood on JIA.

METHODS

The study includes the patients diagnosed with JIA and regularly followed up at the Department of Pediatric Rheumatology in Istanbul University-Cerrahpasa. The comparison group consisted of healthy subjects and patients with juvenile systemic lupus erythematosus (jSLE). A face-to-face survey method was conducted with the parents of the participants between February 1, 2021, and September 1, 2021.

RESULTS

The mean age of the JIA cohort (n = 324) was 12.2 ± 4.7 years, with a female ratio of 64.8%. The breastfeeding rate differed from the control groups (253 healthy subjects and 88 patients with jSLE) but was higher with a value of 94.8%. There was no difference between the groups (P = .097, P = .064) or within the subgroups of JIA (P = .12) regarding breastfeeding duration. Cow's milk introduction time (P = .02, P = .0001), household pet-keeping (P = .001), income level (P = .0001), maternal literacy (P = 0.013) made a statistical difference vs the control groups.

CONCLUSION

No relationship was established between the rate or duration of breastfeeding and the development or severity of JIA. The early introduction of cow's milk was found to be higher in the patient cohorts. The income level and maternal literacy appeared to be relevant with the high disability and damage scores, and frequent relapse rates. Secondhand smoking, higher in JIA, may prompt the basis of primary preventable strategies in JIA.

Abnormal lower expression of GPR183 in peripheral blood T and B cell subsets of systemic lupus erythematosus patients

G protein-coupled receptor 183 (GPR183) has been indicated to mediate the migration and localisation of immune cells in T cell-dependent antibody responses. Systemic lupus erythematosus (SLE) is a canonical autoimmune disease involving B cell-mediated tolerance destruction and excessive pathogenic autoantibody production, in which multiple GPCRs play a role. To date, there has been no systematic study regarding the expression of GPR183 in lymphocyte subsets of SLE patients. In this research, firstly, we observed the expression trends of GRP183 in various T and B cell subsets in human tonsil tissues. These lymphocyte subsets include CD4⁺, CD8⁺, naïve T, effector T, Tfh, activated Tfh, Th1, Th2, Th17, Treg, CD19⁺CD27^-, CD19⁺CD27⁺, naïve B, germinal centre B, memory B, and plasma cells. Further, compared with healthy controls (HCs), GPR183 expression levels in above peripheral blood lymphocyte subsets of patients with SLE were reduced overall. The differential expression of GPR183 expression between inactive and active SLE patients indicates that GPR183 expression may be concerned with the disease activity of SLE. This was further confirmed through the strong negative correlation with SLEDAI score and positive correlation with serum complement protein C3, C4 and C1q levels. Further receiver operating characteristic (ROC) curve analysis revealed that GPR183 expression in circulating CD27^-IgD⁺ B cells may be beneficial in distinguishing between inactive and active SLE patients. In addition, type I interferon stimulation could down-regulate the expression of GPR183 in peripheral blood T and B cell subsets. Aberrant expression of GPR183 may provide some novel insights into disease activity prediction and underlying pathogenesis of SLE.

Case report of severe constrictive perimyocarditis and ischemic hepatitis in a Crohn's disease patient upon infliximab-induced lupus-like syndrome

Anti-tumor necrosis factor (TNF) antibodies have become an indispensable part in the therapeutic landscape of treating inflammatory bowel disease (IBD) patients. Nevertheless, they can be associated with the occurrence of severe systemic side effects. Here, we report the case of a 23-year-old patient with ileocolonic Crohn's disease in endoscopic remission under ongoing anti-TNF infliximab therapy with occurrence of novel generalized arthralgia, pleuritic chest pain, and dyspnea. Clinical, laboratory, and imaging diagnostic workup in an extended clinical routine setting at the University Hospital of Erlangen, Germany, was used by a multidisciplinary team consisting of gastroenterologists, radiologists, cardiologists, and rheumatologists to investigate the underlying cause of the clinical symptoms in the patient. The results received using the aforementioned diagnostic setup led to the diagnosis of severe constrictive perimyocarditis due to infliximab-induced lupus-like syndrome with distinct ANA reactivity and elevated anti-dsDNA levels. Furthermore, pronounced ischemic hepatitis was diagnosed. Infliximab treatment was immediately stopped, and initiated corticosteroid pulse therapy only led to partial response as it had to be reduced due to pronounced psychiatric side effects. Persistent signs of pericarditis required additional ibuprofen therapy, which led to subsequent resolution of cardial symptoms. Formerly elevated liver enzymes returned to normal, and there were no clinical signs of recurrence of Crohn's disease activity over 18 months of follow-up. The patient was subsequently switched to ustekinumab therapy for further treatment of underlying Crohn's disease. This case report describes for the first time severe infliximab-induced lupus-like syndrome in an IBD patient, concurrently mimicking ST-elevation myocardial infarction with MRI visualization of pericarditis, occurrence of ischemic hepatitis, and pronounced signs of systemic inflammation.

Hidden mysteries behind genome, epigenome, and exposome of lupus erythematosus

As an extremely heterogeneous disease, lupus erythematosus (LE) occurs when a genetically susceptible individual encounters specific environmental triggers. Epigenetics bridges genetics and environment and helps explain their interactions. Comprehensively understanding the hidden mysteries behind the genome, epigenome, and exposome of lupus could contribute to precision prevention and treatment of lupus.

The role of maternal methylation in the association between prenatal meteorological conditions and neonatal H19/H19-DMR methylation

Meteorological conditions during pregnancy can affect birth outcome, which has been linked to the H19/H19-differentially methylated region (DMR). However, the detailed mechanisms underlying this association are unclear. This was investigated in the present study to provide epidemiological evidence for elucidating the pathogenesis of adverse birth outcomes. A total of 550 mother-newborn pairs were recruited in Zhengzhou, China from January 2010 to January 2012. Meteorological data including temperature (T), relative humidity (RH), and sunshine duration (SSD) were obtained from the China Meteorological Data Sharing Service System. Bisulfite sequencing PCR was performed to determine the methylation levels of H19/H19-DMR using genomic DNA extracted from maternal peripheral and umbilical cord blood. The results showed that H19-DMR methylation status in cord blood was positively associated with that in maternal blood. Neonatal H19-DMR methylation was negatively associated with T and RH during the first trimester and positively associated with these variables during the third trimester. There was a positive correlation between neonatal H19-DMR methylation and SSD during the second trimester and a negative correlation during the third trimester. Similar associations were observed between maternal H19-DMR methylation and prenatal meteorological conditions. We also observed significant interaction effects of maternal H19/H19-DMR methylation and most prenatal meteorological factors on neonatal methylation, and found that changes in the methylation status of maternal H19-DMR were responsible for the effects of prenatal meteorological conditions on neonatal methylation. In summary, neonatal H19-DMR methylation was significantly associated with prenatal meteorological conditions, which was modified and mediated by maternal H19-DMR methylation changes. These findings provide insights into the relationship between meteorological factors during pregnancy and adverse birth outcomes or disease susceptibility in offspring, and can serve as a reference for environmental policy-making.

Epigenetic studies and pediatric research

The 2020 Annual Review Issue, "Preventing Disease in the 21st Century" was selected by the Editors-in-Chief of Pediatric Research to include a variety of disease entities that confront health-care practitioners entrusted to the care of infants and children. In keeping with this mandate, this article reviews the subject of epigenetics, which impacts pediatric research from bench to bedside. Epigenetic mechanisms exert their effects through the interaction of environment, various susceptibility genes, and immunologic development and include: (1) DNA methylation; (2) posttranslational modifications of histone proteins through acetylation and methylation, and (3) RNA-mediated gene silencing by microRNA (miRNA) regulation. The effects of epigenetics during fetal life and early periods of development are first reviewed together with clinical applications of cardiovascular and metabolic disorders in later life. The relationships of epigenetics to the allergic and autoimmune diseases and cancer are next reviewed. A specific focus of the article is directed to the recent recognition that many of these disorders are driven by aberrant immune responses in which immunoregulatory events are often poorly functioning and where through interventive epigenetic measures prevention may be possible by alterations in programming of DNA during fetal and early periods as well as in later life.

The study of interactions between genome and exposome in the development of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic inflammatory autoimmune disease characterized by a broad spectrum of clinical and serological manifestations. This may reflect a complex and multifactorial etiology involving several identified genetic and environmental factors, though not explaining the full risk of SLE. Established SLE risk genotypes are either very rare or with modest effect sizes and twin studies indicate that other factors besides genetics must be operative in SLE etiology. The exposome comprises the cumulative environmental influences on an individual and associated biological responses through the lifespan. It has been demonstrated that exposure to silica, smoking and exogenous hormones candidate as environmental risk factors in SLE, while alcohol consumption seems to be protective. Very few studies have investigated potential gene-environment interactions to determine if some of the unexplained SLE risk is attributable hereto. Even less have focused on interactions between specific risk genotypes and environmental exposures relevant to SLE pathogenesis. Cohort and case-control studies may provide data to suggest such biological interactions and various statistical measures of interaction can indicate the magnitude of such. However, such studies do often have very large sample-size requirements and we suggest that the rarity of SLE to some extent can be compensated by increasing the ratio of controls. This review summarizes the current body of knowledge on gene-environment interactions in SLE. We argue for the prioritization of studies that comprise the increasing details available of the genome and exposome relevant to SLE as they have the potential to disclose new aspects of SLE pathogenesis including phenotype heterogeneity.

Sex Hormones in Acquired Immunity and Autoimmune Disease

Women have stronger immune responses to infections and vaccination than men. Paradoxically, the stronger immune response comes at a steep price, which is the high incidence of autoimmune diseases in women. The reasons why women have stronger immunity and higher incidence of autoimmunity are not clear. Besides gender, sex hormones contribute to the development and activity of the immune system, accounting for differences in gender-related immune responses. Both innate and adaptive immune systems bear receptors for sex hormones and respond to hormonal cues. This review focuses on the role of sex hormones particularly estrogen, in the adaptive immune response, in health, and autoimmune disease with an emphasis on systemic lupus erythematosus.

Drug-induced lupus: Traditional and new concepts

Drug-induced lupus (DIL) includes a spectrum of drug-induced reactions often characterised by a clinical phenotype similar to that of idiopathic systemic lupus eruthematosus (SLE) but usually lacking major SLE complications. Different drugs may be associated with distinct clinical and serological profiles, and early recognition is crucial. Drugs traditionally associated with DIL include procainamide, hydralazine, quinidine and others, but strong associations with newer agents, such as TNF α (TNFα) inhibitors, are increasingly recognised. The pathogenic mechanisms explaining how drugs that have heterogeneous chemical structure and function lead to autoimmunity are only partially understood. However, it is likely that traditional DIL-associated agents can boost innate immune responses, particularly neutrophil responses, with neutrophil extracellular trap (NET) formation and exposure of autoantigens. Research in the field of DIL is evolving and may provide interesting models for the study of autoimmunity.