Differential Pulmonary Toxicity and Autoantibody Formation in Genetically Distinct Mouse Strains Following Combined Exposure to Silica and Diesel Exhaust Particles.

Background: Inhalation of airborne particulate matter, such as silica and diesel exhaust particles, poses serious long-term respiratory health risks. Silica exposure can lead to silicosis and systemic autoimmune diseases, while DEP exposure is linked to asthma and cancer. Combined exposure to silica and DEP, common in mining, may have more severe effects. This study investigates the separate and combined effects of silica and DEP on lung injury, inflammation, and autoantibody formation in two genetically distinct mouse strains, thereby aiming at understanding the interplay between genetic susceptibility, particulate exposure, and disease outcomes. Silica and diesel exhaust particles were administered to mice via oropharyngeal aspiration. Assessments of lung injury and host response included in vivo lung micro-computed tomography, lung function tests, bronchoalveolar lavage fluid analysis including inflammatory cytokines and antinuclear antibodies, and histopathology with particle colocalization. Results: Silica exposure elicited a well-established inflammatory response marked by inflammatory infiltrates, release of cytokines, and chemokines, alongside limited fibrosis, indicated by collagen deposition in the lungs of both C57BL/6J and NOD/ShilLtJ mice. Notably, these strains exhibited divergent responses in terms of respiratory function and lung volumes, as assessed through micro-computed tomography. Additionally, silica exposure induced airway hyperreactivity and elevated antinuclear antibody levels in bronchoalveolar lavage fluid, particularly prominent in NOD/ShiLtJ mice. Lung tissue analysis revealed DEP loaded macrophages and co-localization of silica and DEP particles. Conclusion: Mouse strain variations exerted a substantial influence on the development of silica induced lung alterations. Furthermore, the additional impact of diesel exhaust particles on these silica-induced effects was minimal.

Dose adjustments of Elexacaftor/Tezacaftor/Ivacaftor in response to mental health side effects in adults with cystic fibrosis.

INTRODUCTION: Deterioration in mental health has been reported in a minority of individuals with cystic fibrosis starting elexacafor/tezacaftor/ivacaftor (ELX/TEZ/IVA). We report our experience of using sweat chloride and markers of clinical stability to titrate dose reduction with the aim of minimising adverse events and maintaining clinical stability. METHOD: Adults (n = 266) prescribed ELX/TEZ/IVA, were included. Adverse events, sweat chloride, lung function and clinical data were collected. RESULTS: Nineteen (7.1%) individuals reported anxiety, low mood, insomnia and "brain fog" with reduced attention and concentration span. Thirteen underwent dose reduction with sweat chloride remained normal (<30 mmol l-1) or borderline (30-60 mmol l-1) in six (46.2%) and seven (53.2%) cases respectively. Improvement or resolution of AEs occurring in 10 of the 13 cases. CONCLUSION: Dose adjustment of ELX/TEZ/IVA was associated with improvement in mental health AEs without significant clinical deterioration. Sweat chloride concentration may prove useful as a surrogate marker of CFTR function.

Exposure to silicates and systemic autoimmune-related outcomes in rodents: a systematic review.

BACKGROUND: Autoimmunity can result from the interplay between genetic background and effects of environmental and/or occupational exposure to hazardous materials. Several compounds, including silica dust, have been linked with systemic autoimmunity and systemic autoimmune diseases, based on epidemiological evidence. For asbestos, a strong link with systemic autoimmune diseases does not yet exist, however, several studies have documented features of autoimmunity following asbestos exposure. Even so, human studies are limited in their ability to identify and examine isolated exposures, making it difficult to demonstrate causation or to assess pathogenic mechanisms. Therefore, this systematic review examines the existing animal evidence regarding autoimmunity and exposure to silicates (silica and asbestos). METHODS: PubMed and EMBASE were systematically searched for peer-reviewed studies examining systemic autoimmune disease-related outcomes after silicate exposure in rodents. Literature databases were searched up to September 2021 for studies written in English and where the full text was available. Search strings were established based on a PECO (Population, Exposure, Comparator, Outcome) format. After title, abstract, and full-text screening, thirty-four studies were identified for further analysis. Quality assessment through ToxR tool and qualitative analysis of the results was performed. RESULTS: Although there was significant heterogeneity in the included studies in terms of exposure protocol and genetic background of the rodent models used, it was noted that both genetic background and exposure to silicates [(crystalline) silica and asbestos] are highly relevant to the development of (sub-) clinical systemic autoimmune disease. CONCLUSION: Parallels were observed between the findings from the animal (this review) and human (epidemiological) studies, arguing that experimental animal models are valuable tools for examining exacerbation or development of autoimmune disease after silicate exposure. However, genetic background and synergism between exposures should be considered in future studies.

Battling the biotypes of balsam: the biological control of Impatiens glandulifera using the rust fungus Puccinia komarovii var. glanduliferae in GB.

Impatiens glandulifera, or Himalayan balsam, is a prolific invader of riverine habitats. Introduced from the Himalayas for ornamental purposes in 1839, this annual species has naturalised across Great Britain (GB) forming dense monocultures with negative affects across whole ecosystems. In 2006 a programme exploring biocontrol as an alternative control method was initiated and to date, two strains of the rust fungus Puccinia komarovii var. glanduliferae have been released. To better understand the observed differences in susceptibility of GB Himalayan balsam stands to the two rust strains, inoculation studies were conducted using urediniospores and basidiospores. Experiments revealed large variation in the susceptibility of stands to urediniospores of the two rust strains, with some resistant to both. Furthermore, the infectivity of basidiospores was found to differ, with some stands fully susceptible to the urediniospore stage, being immune to basidiospore infection. Therefore, before further rust releases at new sites, it is necessary to ensure complete compatibility of the invasive stands with both urediniospores and basidiospores. However, for successful control across GB it is essential that plant biotypes are matched to the most virulent rust strains. This will involve additional strains from the native range to tackle those biotypes resistant to the strains currently released.

Mechanisms of Environment-Induced Autoimmunity.

Although numerous environmental exposures have been suggested as triggers for preclinical autoimmunity, only a few have been confidently linked to autoimmune diseases. For disease-associated exposures, the lung is a common site where chronic exposure results in cellular toxicity, tissue damage, inflammation, and fibrosis. These features are exacerbated by exposures to particulate material, which hampers clearance and degradation, thus facilitating persistent inflammation. Coincident with exposure and resulting pathological processes is the posttranslational modification of self-antigens, which, in concert with the formation of tertiary lymphoid structures containing abundant B cells, is thought to promote the generation of autoantibodies that in some instances demonstrate major histocompatibility complex restriction. Under appropriate gene-environment interactions, these responses can have diagnostic specificity. Greater insight into the molecular and cellular requirements governing this process, especially those that distinguish preclinical autoimmunity from clinical autoimmunedisease, may facilitate determination of the significance of environmental exposures in human autoimmune disease.

Facial shape and allometry quantitative trait locus intervals in the Diversity Outbred mouse are enriched for known skeletal and facial development genes.

The biology of how faces are built and come to differ from one another is complex. Discovering normal variants that contribute to differences in facial morphology is one key to untangling this complexity, with important implications for medicine and evolutionary biology. This study maps quantitative trait loci (QTL) for skeletal facial shape using Diversity Outbred (DO) mice. The DO is a randomly outcrossed population with high heterozygosity that captures the allelic diversity of eight inbred mouse lines from three subspecies. The study uses a sample of 1147 DO animals (the largest sample yet employed for a shape QTL study in mouse), each characterized by 22 three-dimensional landmarks, 56,885 autosomal and X-chromosome markers, and sex and age classifiers. We identified 37 facial shape QTL across 20 shape principal components (PCs) using a mixed effects regression that accounts for kinship among observations. The QTL include some previously identified intervals as well as new regions that expand the list of potential targets for future experimental study. Three QTL characterized shape associations with size (allometry). Median support interval size was 3.5 Mb. Narrowing additional analysis to QTL for the five largest magnitude shape PCs, we found significant overrepresentation of genes with known roles in growth, skeletal and facial development, and sensory organ development. For most intervals, one or more of these genes lies within 0.25 Mb of the QTL's peak. QTL effect sizes were small, with none explaining more than 0.5% of facial shape variation. Thus, our results are consistent with a model of facial diversity that is influenced by key genes in skeletal and facial development and, simultaneously, is highly polygenic.

Ebola-Specific CD8+ and CD4+ T-Cell Responses in Sierra Leonean Ebola Virus Survivors With or Without Post-Ebola Sequelae.

BACKGROUND: Ebola virus (EBOV) disease has killed thousands of West and Central Africans over the past several decades. Many who survive the acute disease later experience post-Ebola syndrome, a constellation of symptoms whose causative pathogenesis is unclear. METHODS: We investigated EBOV-specific CD8+ and CD4+ T-cell responses in 37 Sierra Leonean EBOV disease survivors with (n = 19) or without (n = 18) sequelae of arthralgia and ocular symptoms. Peripheral blood mononuclear cells were infected with recombinant vesicular stomatitis virus encoding EBOV antigens. We also studied the presence of EBOV-specific immunoglobulin G, antinuclear antibodies, anti-cyclic citrullinated peptide antibodies, rheumatoid factor, complement levels, and cytokine levels in these 2 groups. RESULTS: Survivors with sequelae had a significantly higher EBOV-specific CD8+ and CD4+ T-cell response. No differences in EBOV-specific immunoglobulin G, antinuclear antibody, or anti-cyclic citrullinated peptide antibody levels were found. Survivors with sequelae showed significantly higher rheumatoid factor levels. CONCLUSION: EBOV-specific CD8+ and CD4+ T-cell responses were significantly higher in Ebola survivors with post-Ebola syndrome. These findings suggest that pathogenesis may occur as an immune-mediated disease via virus-specific T-cell immune response or that persistent antigen exposure leads to increased and sustained T-cell responses.

Perspective: The Lung, Particles, Fibers, Nanomaterials, and Autoimmunity.

Studies have shown that a wide range of factors including drugs, chemicals, microbes, and other environmental agents can induce pre-clinical autoimmunity. However, only a few have been confidently linked to autoimmune diseases. Among these are exposures to inhaled particulates that are known to be associated with autoimmune diseases such as lupus and rheumatoid arthritis. In this article, the potential of particle, fiber, and nanomaterial exposures to induce autoimmunity is discussed. It is hypothesized that inhalation of particulate material known to be associated with human autoimmune diseases, such as cigarette smoke and crystalline silica, results in a complex interplay of a number of pathological processes, including, toxicity, oxidative stress, cell and tissue damage, chronic inflammation, post-translational modification of self-antigens, and the formation of lymphoid follicles that provide a milieu for the accumulation of autoreactive B and T cells necessary for the development and persistence of autoimmune responses, leading to disease. Although experimental studies show nanomaterials are capable of inducing several of the above features, there is no evidence that this matures to autoimmune disease. The procession of events hypothesized here provides a foundation from which to pursue experimental studies to determine the potential of other environmental exposures to induce autoimmunity and autoimmune disease.

Mercury-induced inflammation and autoimmunity.

BACKGROUND: Human exposure to mercury leads to a variety of pathologies involving numerous organ systems including the immune system. A paucity of epidemiological studies and suitable diagnostic criteria, however, has hampered collection of sufficient data to support a causative role for mercury in autoimmune diseases. Nevertheless, there is evidence that mercury exposure in humans is linked to markers of inflammation and autoimmunity. This is supported by experimental animal model studies, which convincingly demonstrate the biological plausibility of mercury as a factor in the pathogenesis of autoimmune disease. SCOPE OF THE REVIEW: In this review, we focus on ability of mercury to elicit inflammatory and autoimmune responses in both humans and experimental animal models. MAJOR CONCLUSIONS: Although subtle differences exist, the inflammatory and autoimmune responses elicited by mercury exposure in humans and experimental animal models show many similarities. Proinflammatory cytokine expression, lymphoproliferation, autoantibody production, and nephropathy are common outcomes. Animal studies have revealed significant strain dependent differences in inflammation and autoimmunity suggesting genetic regulation. This has been confirmed by the requirement for individual genes as well as genome wide association studies. Importantly, many of the genes required for mercury-induced inflammation and autoimmunity are also required for idiopathic systemic autoimmunity. A notable difference is that mercury-induced autoimmunity does not require type I IFN. This observation suggests that mercury-induced autoimmunity may arise by both common and specific pathways, thereby raising the possibility of devising criteria for environmentally associated autoimmunity. GENERAL SIGNIFICANCE: Mercury exposure likely contributes to the pathogenesis of autoimmunity.

Environmental Xenobiotic Exposure and Autoimmunity.

Susceptibility to autoimmune diseases is dependent on multigenic inheritance, environmental factors, and stochastic events. Although there has been substantial progress in identifying predisposing genetic variants, a significant challenge facing autoimmune disease research is the identification of the specific events that trigger loss of tolerance, autoreactivity and ultimately autoimmune disease. Accordingly, studies have indicated that a wide range of extrinsic factors including drugs, chemicals, microbes, and other environmental factors can induce autoimmunity, particularly systemic autoimmune diseases such as lupus. This review describes a class of environmental factors, namely xenobiotics, epidemiologically linked to human autoimmunity. Mechanisms of xenobiotic autoimmune disease induction are discussed in terms of human and animal model studies with a focus on the role of inflammation and the innate immune response. We argue that localized tissue damage and chronic inflammation elicited by xenobiotic exposure leads to the release of self-antigens and damage-associated molecular patterns as well as the appearance of ectopic lymphoid structures and secondary lymphoid hypertrophy, which provide a milieu for the production of autoreactive B and T cells that contribute to the development and persistence of autoimmunity in predisposed individuals.

Developmental constraint through negative pleiotropy in the zygomatic arch.

BACKGROUND: Previous analysis suggested that the relative contribution of individual bones to regional skull lengths differ between inbred mouse strains. If the negative correlation of adjacent bone lengths is associated with genetic variation in a heterogeneous population, it would be an example of negative pleiotropy, which occurs when a genetic factor leads to opposite effects in two phenotypes. Confirming negative pleiotropy and determining its basis may reveal important information about the maintenance of overall skull integration and developmental constraint on skull morphology. RESULTS: We identified negative correlations between the lengths of the frontal and parietal bones in the midline cranial vault as well as the zygomatic bone and zygomatic process of the maxilla, which contribute to the zygomatic arch. Through gene association mapping of a large heterogeneous population of Diversity Outbred (DO) mice, we identified a quantitative trait locus on chromosome 17 driving the antagonistic contribution of these two zygomatic arch bones to total zygomatic arch length. Candidate genes in this region were identified and real-time PCR of the maxillary processes of DO founder strain embryos indicated differences in the RNA expression levels for two of the candidate genes, Camkmt and Six2. CONCLUSIONS: A genomic region underlying negative pleiotropy of two zygomatic arch bones was identified, which provides a mechanism for antagonism in component bone lengths while constraining overall zygomatic arch length. This type of mechanism may have led to variation in the contribution of individual bones to the zygomatic arch noted across mammals. Given that similar genetic and developmental mechanisms may underlie negative correlations in other parts of the skull, these results provide an important step toward understanding the developmental basis of evolutionary variation and constraint in skull morphology.

Induction of Systemic Autoimmunity by a Xenobiotic Requires Endosomal TLR Trafficking and Signaling from the Late Endosome and Endolysosome but Not Type I IFN.

Type I IFN and nucleic acid-sensing TLRs are both strongly implicated in the pathogenesis of lupus, with most patients expressing IFN-induced genes in peripheral blood cells and with TLRs promoting type I IFNs and autoreactive B cells. About a third of systemic lupus erythematosus patients, however, lack the IFN signature, suggesting the possibility of type I IFN-independent mechanisms. In this study, we examined the role of type I IFN and TLR trafficking and signaling in xenobiotic systemic mercury-induced autoimmunity (HgIA). Strikingly, autoantibody production in HgIA was not dependent on the type I IFN receptor even in NZB mice that require type I IFN signaling for spontaneous disease, but was dependent on the endosomal TLR transporter UNC93B1 and the endosomal proton transporter, solute carrier family 15, member 4. HgIA also required the adaptor protein-3 complex, which transports TLRs from the early endosome to the late endolysosomal compartments. Examination of TLR signaling pathways implicated the canonical NF-κB pathway and the proinflammatory cytokine IL-6 in autoantibody production, but not IFN regulatory factor 7. These findings identify HgIA as a novel type I IFN-independent model of systemic autoimmunity and implicate TLR-mediated NF-κB proinflammatory signaling from the late endocytic pathway compartments in autoantibody generation.

Fungal contamination of nebuliser devices used by people with cystic fibrosis.

BACKGROUND: Poor nebuliser hygiene can result in bacterial contamination and risk of infections. The aim of this study was to assess the prevalence of fungal contamination of nebulisers used by adults with cystic fibrosis. METHODS: A total of 170 nebulisers from 149 subjects were screened by wetting a sterile cotton swab with sterile water and swabbing each drug chamber. The swab was then plated out on Sabouraud and on Scel+agar and incubated at 27 °C for up to 2 weeks. RESULTS: Fungal cultures were positive in 86 (57.7%) patient's devices. In 28/149 (18.8%), 39/149 (26.2%), 47/149 (31.5%) and 20/149 (13.4%) of subjects Aspergillus species, yeasts, moulds and both yeasts and moulds were isolated respectively. There was no difference in contamination rates between different devices. CONCLUSION: Nebuliser devices are frequently contaminated by moulds and yeasts and emphasis should be placed on ensuring adequate nebuliser hygiene.

The effect of the autoimmunity-associated gene, PTPN22, on a BXSB-derived model of lupus.

A single nucleotide polymorphism in PTPN22 is linked to increased disease susceptibility in a range of autoimmune diseases including systemic lupus erythematosus (SLE). PTPN22 encodes the Lyp phosphatase that dampens TCR signaling and is necessary for signaling downstream of toll-like receptors in myeloid cells. To understand these dual functions in disease, we examined the impact of deficiency in PTPN22 on a spontaneous murine model of SLE. Male PTPN22 KO mice carrying BXSB chromosome 1 and the Yaa disease accelerating factor developed disease at a similar rate and severity as PTPN22 WT. In contrast, although female mice showed no differences in survival in the absence of PTPN22, autoantibody production was significantly increased and splenic populations associated with pathogenesis in this model were expanded in the PTPN22 KO group. These findings support the notion that when coupled with other predisposing autoimmunity genes, PTPN22 deficiency contributes to a predisposition to lupus pathogenesis.

Cathepsin B regulates the appearance and severity of mercury-induced inflammation and autoimmunity.

Susceptibility and resistance to systemic autoimmunity are genetically regulated. This is particularly true for murine mercury-induced autoimmunity (mHgIA) where DBA/2J mice are considered resistant to disease including polyclonal B cell activation, autoantibody responses, and immune complex deposits. To identify possible mechanisms for the resistance to mHgIA, we exposed mHgIA sensitive B10.S and resistant DBA/2J mice to HgCl2 and assessed inflammation and pro-inflammatory responses at the site of exposure and subsequent development of markers of systemic autoimmunity. DBA/2J mice showed little evidence of induration at the site of exposure, expression of proinflammatory cytokines, T cell activation, or autoantibody production, although they did exhibit increased levels of total serum IgG and IgG1. In contrast B10.S mice developed significant inflammation together with increased expression of inflammasome component NLRP3, proinflammatory cytokines IL-1ß, TNF-α, and IFN-γ, hypergammaglobulinemia, splenomegaly, CD4(+) T-cell activation, and production of autoantibodies. Inflammation in B10.S mice was associated with a selective increase in activity of cysteine cathepsin B but not cathepsins L or S. Increased cathepsin B activity was not dependent on cytokines required for mHgIA but treatment with CA-074, a cathepsin B inhibitor, led to transient reduction of local induration, expression of inflammatory cytokines, and subsequent attenuation of the systemic adaptive immune response. These findings demonstrate that sensitivity to mHgIA is linked to an early cathepsin B regulated inflammatory response which can be pharmacologically exploited to abrogate the subsequent adaptive autoimmune response which leads to disease.

Genome-wide distribution of Auts2 binding localizes with active neurodevelopmental genes.

The autism susceptibility candidate 2 gene (AUTS2) has been associated with multiple neurological diseases including autism spectrum disorders (ASDs). Previous studies showed that AUTS2 has an important neurodevelopmental function and is a suspected master regulator of genes implicated in ASD-related pathways. However, the regulatory role and targets of Auts2 are not well known. Here, by using ChIP-seq (chromatin immunoprecipitation followed by deep sequencing) and RNA-seq on mouse embryonic day 16.5 forebrains, we elucidated the gene regulatory networks of Auts2. We find that the majority of promoters bound by Auts2 belong to genes highly expressed in the developing forebrain, suggesting that Auts2 is involved in transcriptional activation. Auts2 non-promoter-bound regions significantly overlap developing brain-associated enhancer marks and are located near genes involved in neurodevelopment. Auts2-marked sequences are enriched for binding site motifs of neurodevelopmental transcription factors, including Pitx3 and TCF3. In addition, we characterized two functional brain enhancers marked by Auts2 near NRXN1 and ATP2B2, both ASD-implicated genes. Our results implicate Auts2 as an active regulator of important neurodevelopmental genes and pathways and identify novel genomic regions that could be associated with ASD and other neurodevelopmental diseases.

Mercury, autoimmunity, and environmental factors on cheyenne river sioux tribal lands.

Mercury (Hg), shown to induce autoimmune disease in rodents, is a ubiquitous toxicant throughout Cheyenne River Sioux Tribe (CRST) lands. CRST members may be exposed to Hg through fish consumption (FC), an important component of native culture that may supplement household subsistence. Our goals were to ascertain whether total blood Hg levels (THg) reflect Hg exposure through FC and smoking, and determine whether THg is associated with the presence of anti-nuclear antibody (ANA) and specific autoantibodies (sAuAb). We recruited 75 participants who regularly consume fish from CRST waters. Hg exposure through FC and smoking were assessed via questionnaires. Whole blood samples were collected from participants, and THg was measured using ICP-MS. ANA and sAuAb in serum were modeled using demographic and exposure information as predictors. Female gender, age, and FC were significant predictors of THg and sAuAb; self-reported smoking was not. 31% of participants tested positive for ANA ≥ 2+. Although ANA was not significantly associated with Hg, the interactions of gender with Hg and proximity to arsenic deposits were statistically significant (P < 0.05). FC resulted in a detectable body burden of Hg, but THg alone did not correlate with the presence of ANA or sAuAb in this population.