Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-11 (of 11 Records) |
Query Trace: Germolec DR[original query] |
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Consensus on the key characteristics of immunotoxic agents as a basis for hazard identification
Germolec DR , Lebrec H , Anderson SE , Burleson GR , Cardenas A , Corsini E , Elmore SE , Kaplan BLF , Lawrence BP , Lehmann GM , Maier CC , McHale CM , Myers LP , Pallardy M , Rooney AA , Zeise L , Zhang L , Smith MT . Environ Health Perspect 2022 130 (10) 105001 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. |
Inhalation of Stachybotrys chartarum fragments induces pulmonary arterial remodeling
Croston TL , Lemons AR , Barnes MA , Goldsmith WT , Orandle MS , Nayak AP , Germolec DR , Green BJ , Beezhold DH . Am J Respir Cell Mol Biol 2019 62 (5) 563-576 Stachybotrys chartarum is a fungal contaminant within the built environment and a respiratory health concern in the United States. The objective of this study was to characterize the mechanisms influencing pulmonary immune responses to repeatedly inhaled S. chartarum. Groups of B6C3F1/N mice repeatedly inhaled viable trichothecene-producing S. chartarum conidia (Strain A or Strain B), heat-inactivated conidia, or HEPA-filtered air twice a week for 4 and 13 weeks. Strain A was found to produce higher amounts of respirable fragments compared to Strain B. Lung tissue, serum and bronchoalveolar lavage fluid (BALF) were collected at 24 and 48 hours following final exposure and processed for histology, flow cytometry, RNA, and proteomic analyses. At 4 weeks post-exposure, a Th2-mediated response was observed. After 13 weeks, a mixed T-cell response was observed following exposure to Strain A, compared to a Th2-mediated response following Strain B exposure. Following exposure, both strains induced pulmonary arterial remodeling at 13 weeks; however, Strain A-exposed mice progressed more quickly compared to Strain B-exposed mice. BALF was composed primarily of eosinophils, neutrophils, and macrophages. Both the immune response and the observed pulmonary arterial remodeling were supported by specific cellular, molecular, and proteomic profiles. The immunopathological responses occurred earlier in mice exposed to high fragment-producing Strain A. The rather striking induction of pulmonary remodeling by S. chartarum appears to be related to the presence of fungal fragments during exposure. |
Aspergillus fumigatus viability drives allergic responses to inhaled conidia
Nayak AP , Croston TL , Lemons AR , Goldsmith WT , Marshall NB , Kashon ML , Germolec DR , Beezhold DH , Green BJ . Ann Allergy Asthma Immunol 2018 121 (2) 200-210 e2 BACKGROUND: Aspergillus fumigatus induced allergic airway disease has been shown to involve conidial germination in vivo but the immunological mechanisms remain uncharacterized. OBJECTIVE: A subchronic murine exposure model was used to examine the immunological mediators that are regulated in response to either culturable or non-culturable A. fumigatus conidia. METHODS: Female B6C3F1/N mice were repeatedly dosed via inhalation with 1 x 105 viable or heat inactivated conidia (HIC), twice a week for 13 weeks (26 exposures). Control mice inhaled HEPA-filtered air. The influence of A. fumigatus conidial germination on the pulmonary immunopathological outcomes was evaluated by flow cytometry analysis of cellular infiltration in the airways, assessment of lung mRNA expression, and quantitative proteomics and histopathology of whole lung tissue. RESULTS: Repeated inhalation of viable conidia, but not HIC, resulted in allergic inflammation marked by vascular remodeling, extensive eosinophilia, and accumulation of alternatively activated macrophages (AAMs) in the murine airways. More specifically, mice that inhaled viable conidia resulted in a mixed TH1 and TH2 (IL-13) cytokine response. Recruitment of eosinophils corresponded with increased Ccl11 transcripts. Furthermore, genes associated with M2 or alternatively activated macrophage polarization (e.g. Arg1, Chil3 and Retnla) were significantly upregulated in viable A. fumigatus exposed mice. In mice inhaling HIC, CD4+ T cells expressing IFN-gamma (TH1) dominated the lymphocytic infiltration. Quantitative proteomics of the lung revealed metabolic reprogramming accompanied by mitochondrial dysfunction and endoplasmic reticulum stress stimulated by oxidative stress from repetitive microbial insult. CONCLUSION: Our studies demonstrate that A. fumigatus conidial viability in vivo is critical to the immunopathological presentation of chronic fungal allergic disease. |
Influence of Aspergillus fumigatus conidia viability on murine pulmonary microRNA and mRNA expression following subchronic inhalation exposure.
Croston TL , Nayak AP , Lemons AR , Goldsmith WT , Gu JK , Germolec DR , Beezhold DH , Green BJ . Clin Exp Allergy 2016 46 (10) 1315-27 BACKGROUND: Personal exposure to fungal bioaerosols derived from contaminated building materials or agricultural commodities may induce or exacerbate a variety of adverse health effects. The genomic mechanisms that underlie pulmonary immune responses to fungal bioaerosols have remained unclear. OBJECTIVE: The impact of fungal viability on the pulmonary microRNA and messenger RNA profiles that regulate murine immune responses was evaluated following subchronic inhalation exposure to Aspergillus fumigatus conidia. METHODS: Three groups of naive B6C3F1/N mice were exposed via nose-only inhalation to A. fumigatus viable conidia, heat-inactivated conidia, or HEPA-filtered air twice a week for 13 weeks. Total RNA was isolated from whole lung 24 and 48 hours post final exposure and was further processed for gene expression and microRNA array analysis. The molecular network pathways between viable and heat-inactivated conidia groups were evaluated. RESULTS: Comparison of datasets revealed increased Il4, Il13, and Il33 expression in mice exposed to viable versus heat-inactivated conidia. Of 415 microRNAs detected, approximately 50% were altered in mice exposed to viable versus heat-inactivated conidia 48 hours post exposure. Significantly downregulated (P < 0.05) miR-29a-3p was predicted to regulate TGF-beta3 and Clec7a, genes involved in innate responses to viable A. fumigatus. Also significantly downregulated (P < 0.05), miR-23b-3p regulates genes involved in pulmonary IL-13 and IL-33 responses and SMAD2, downstream of TGF-beta signaling. Using Ingenuity Pathway Analysis, a novel interaction was identified between viable conidia and SMAD2/3. CONCLUSION AND CLINICAL RELEVANCE: Examination of the pulmonary genetic profiles revealed differentially expressed genes and microRNAs following subchronic inhalation exposure to A. fumigatus. MicroRNAs regulating genes involved in the pulmonary immune responses were those with the greatest fold change. Specifically, germinating A. fumigatus conidia were associated with Clec7a and were predicted to interact with Il13 and Il33. Furthermore, altered microRNAs may serve as potential biomarkers to evaluate fungal exposure. |
Subchronic exposures to fungal bioaerosols promotes allergic pulmonary inflammation in naive mice
Nayak AP , Green BJ , Lemons AR , Marshall NB , Goldsmith WT , Kashon ML , Anderson SE , Germolec DR , Beezhold DH . Clin Exp Allergy 2016 46 (6) 861-70 BACKGROUND: Epidemiological surveys indicate that occupants of mold contaminated environments are at increased risk of respiratory symptoms. The immunological mechanisms associated with these responses require further characterization. OBJECTIVE: The aim of this study was to characterize the immunotoxicological outcomes following repeated inhalation of dry Aspergillus fumigatus spores aerosolized at concentrations potentially encountered in contaminated indoor environments. METHODS: A. fumigatus spores were delivered to the lungs of naive BALB/cJ mice housed in a multi-animal nose-only chamber twice a week for a period of 13 weeks. Mice were evaluated at 24 and 48 hours post-exposure for histopathological changes in lung architecture, recruitment of specific immune cells to the airways, and serum antibody responses. RESULT: Germinating A. fumigatus spores were observed in lungs along with persistent fungal debris in the perivascular regions of the lungs. Repeated exposures promoted pleocellular infiltration with concomitant epithelial mucus hypersecretion, goblet cell metaplasia, subepithelial fibrosis and enhanced airway hyperreactivity. Cellular infiltration in airways was predominated by CD4+ T cells expressing the pro-allergic cytokine IL-13. Furthermore, our studies show that antifungal T cell responses (IFN-gamma+ or IL-17A+ ) co-expressed IL-13, revealing a novel mechanism for the dysregulated immune response to inhaled fungi. Total IgE production was augmented in animals repeatedly exposed to A. fumigatus. CONCLUSIONS & CLINICAL RELEVANCE: Repeated inhalation of fungal aerosols resulted in significant pulmonary pathology mediated by dynamic shifts in specific immune populations and their cytokines. These studies provide novel insights into the immunological mechanisms and targets that govern the health outcomes that result from repeated inhalation of fungal bioaerosols in contaminated environments. This article is protected by copyright. All rights reserved. |
A murine inhalation model to characterize pulmonary exposure to dry Aspergillus fumigatus conidia
Buskirk AD , Green BJ , Lemons AR , Nayak AP , Goldsmith WT , Kashon ML , Anderson SE , Hettick JM , Templeton SP , Germolec DR , Beezhold DH . PLoS One 2014 9 (10) e109855 Most murine models of fungal exposure are based on the delivery of uncharacterized extracts or liquid conidia suspensions using aspiration or intranasal approaches. Studies that model exposure to dry fungal aerosols using whole body inhalation have only recently been described. In this study, we aimed to characterize pulmonary immune responses following repeated inhalation of conidia utilizing an acoustical generator to deliver dry fungal aerosols to mice housed in a nose only exposure chamber. Immunocompetent female BALB/cJ mice were exposed to conidia derived from Aspergillus fumigatus wild-type (WT) or a melanin-deficient (Deltaalb1) strain. Conidia were aerosolized and delivered to mice at an estimated deposition dose of 1x105 twice a week for 4 weeks (8 total). Histopathological and immunological endpoints were assessed 4, 24, 48, and 72 hours after the final exposure. Histopathological analysis showed that conidia derived from both strains induced lung inflammation, especially at 24 and 48 hour time points. Immunological endpoints evaluated in bronchoalveolar lavage fluid (BALF) and the mediastinal lymph nodes showed that exposure to WT conidia led to elevated numbers of macrophages, granulocytes, and lymphocytes. Importantly, CD8+ IL17+ (Tc17) cells were significantly higher in BALF and positively correlated with germination of A. fumigatus WT spores. Germination was associated with specific IgG to intracellular proteins while Deltaalb1 spores elicited antibodies to cell wall hydrophobin. These data suggest that inhalation exposures may provide a more representative analysis of immune responses following exposures to environmentally and occupationally prevalent fungal contaminants. |
Genetic variants in the major histocompatibility complex class I and class II genes are associated with diisocyanate-induced Asthma.
Yucesoy B , Johnson VJ , Lummus ZL , Kashon ML , Rao M , Bannerman-Thompson H , Frye B , Wang W , Gautrin D , Cartier A , Boulet LP , Sastre J , Quirce S , Tarlo SM , Germolec DR , Luster MI , Bernstein DI . J Occup Environ Med 2014 56 (4) 382-7 OBJECTIVE: To investigate the association between single nucleotide polymorphisms (SNPs) located across the major histocompatibility complex and susceptibility to diisocyanate-induced asthma (DA). METHODS: The study population consisted of 140 diisocyanate-exposed workers. Genotyping was performed using the Illumina GoldenGate major histocompatibility complex panels. RESULTS: The HLA-E rs1573294 and HLA-DPB1 rs928976 SNPs were associated with an increased risk of DA under dominant (odds ratio [OR], 6.27; 95% confidence interval [CI], 2.37 to 16.6; OR, 2.79, 95% CI, 0.99 to 7.81, respectively) and recessive genetic models (OR, 6.27, 95% CI, 1.63 to 24.13; OR, 10.10, 95% CI, 3.16 to 32.33, respectively). The HLA-B rs1811197, HLA-DOA rs3128935, and HLA-DQA2 rs7773955 SNPs conferred an increased risk of DA in a dominant model (OR, 7.64, 95% CI, 2.25 to 26.00; OR, 19.69, 95% CI, 2.89 to 135.25; OR, 8.43, 95% CI, 3.03 to 23.48, respectively). CONCLUSION: These results suggest that genetic variations within HLA genes play a role in DA risk. |
Genetic variants within the MHC region are associated with immune responsiveness to childhood vaccinations.
Yucesoy B , Talzhanov Y , Johnson VJ , Wilson NW , Biagini RE , Wang W , Frye B , Weissman DN , Germolec DR , Luster MI , Barmada MM . Vaccine 2013 31 (46) 5381-91 The influence of genetic variability within the major histocompatibility complex (MHC) region on variations in immune responses to childhood vaccination was investigated. The study group consisted of 135 healthy infants who had been immunized with hepatitis B (HBV), 7-valent pneumococcal conjugate (PCV7), and diphtheria, tetanus, acellular pertussis (DTaP) vaccines according to standard childhood immunization schedules. Genotype analysis was performed on genomic DNA using Illumina Goldengate MHC panels (Mapping and Exon Centric). At the 1 year post vaccination check-up total, isotypic, and antigen-specific serum antibody levels were measured using multiplex immunoassays. A number of single nucleotide polymorphisms (SNPs) within MHC Class I and II genes were found to be associated with variations in the vaccine specific antibody responses and serum levels of immunoglobulins (IgG, IgM) and IgG isotypes (IgG1, IgG4) (all at p<0.001). Linkage disequilibrium patterns and functional annotations showed that significant SNPs were strongly correlated with other functional regulatory SNPs. These SNPs were found to regulate the expression of a group of genes involved in antigen processing and presentation including HLA-A, HLA-C, HLA-G, HLA-H, HLA-DRA, HLA-DRB1, HLA-DRB5, HLA-DQA1, HLA-DQB1, HLA-DOB, and TAP-2. The results suggest that genetic variations within particular MHC genes can influence immune response to common childhood vaccinations, which in turn may influence vaccine efficacy. |
Genetic variants in antioxidant genes are associated with diisocyanate-induced asthma.
Yucesoy B , Johnson VJ , Lummus ZL , Kissling GE , Fluharty K , Gautrin D , Malo JL , Cartier A , Boulet LP , Sastre J , Quirce S , Germolec DR , Tarlo SM , Cruz MJ , Munoz X , Luster MI , Bernstein DI . Toxicol Sci 2012 129 (1) 166-73 Diisocyanates are a common cause of occupational asthma, but risk factors are not well defined. A case-control study was conducted to investigate whether genetic variants of antioxidant defense genes, glutathione S-transferases (GSTM1, GSTT1, GSTM3, GSTP1), manganese superoxide dismutase (SOD2), and microsomal epoxide hydrolase (EPHX1) are associated with increased susceptibility to diisocyanate-induced asthma (DA). The main study population consisted of 353 Caucasian French-Canadians from among a larger sample of 410 diisocyanate-exposed workers in three groups: workers with specific inhalation challenge (SIC) confirmed DA (DA(+), n = 95); symptomatic diisocyanate workers with a negative SIC (DA(-), n = 116); and asymptomatic exposed workers (AW, n = 142). Genotyping was performed on genomic DNA, using a 5'-nuclease PCR assay. The SOD2 rs4880, GSTP1 rs1695, and EPHX1 rs2740171 variants were significantly associated with DA in both univariate and multivariate analyses. In the first logistic regression model comparing DA(+) and DA(-) groups, SOD2 rs4880, GSTM1 (null), GSTP1 rs762803, and EPHX1 rs2854450 variants were associated with DA (p = 0.004, p = 0.047, p = 0.021, p <0.001, respectively). Genotype combinations GSTT1*GSTP1 rs762803, GSTM1*EPHX1 rs2854450, EPHX1 rs2740168*EPHX1 rs1051741, and GSTP1 rs762803*EPHX1 rs2740168 were also associated with DA in this model (p = 0.027, p = 0.002, p = 0.045, p = 0.044, respectively). The GSTP1 rs1695 and EPHX1 rs1051741 and rs2740171 variants showed an association with DA in the second model comparing DA(+) and AW groups (p = 0.040, p = 0.019, p = 0.002, respectively). The GSTM3 rs110913*EPHX1 rs1051741 genotype combination was also associated with DA under this model (p = 0.042). The results suggest that variations in SOD2, GST, and EPHX1 genes and their interactions contribute to DA susceptibility. |
Fungal and atopic sensitization are low among farmers in the Agricultural Health Study
Endres SM , Green BJ , Henneberger PK , Germolec DR , Bledsoe TA , Beezhold DH , London SJ , Alavanja MC , Beane Freeman LE , Hoppin JA . J Allergy Clin Immunol 2012 130 (1) 267-70 e1 Prevalence of fungal sensitization and atopy was lower among farmers than the US population. Fungal sensitization was related to growing specific agricultural commodities. |
Influence of cytokine gene variations on immunization to childhood vaccines
Yucesoy B , Johnson VJ , Fluharty K , Kashon ML , Slaven JE , Wilson NW , Weissman DN , Biagini RE , Germolec DR , Luster MI . Vaccine 2009 27 (50) 6991-7 The magnitude of the immune response to vaccinations can be influenced by genetic variability. In the present study, we aimed to investigate whether cytokine or cytokine receptor gene polymorphisms were associated with variations in the immune response to childhood vaccination. The study group consisted of 141 healthy infants who had been immunized with hepatitis B vaccine (HBV), 7-valent pneumococcal conjugate (PCV7), and diphtheria, tetanus, acellular pertussis (DTaP) vaccines according to standard childhood immunization schedules. Genotype analysis was performed on genomic DNA using a 5' nuclease PCR assay. Post vaccination total, isotypic, and antigen-specific serum antibody levels were measured using multiplex immunoassays. Significant associations were observed between SNPs in the TNFalpha, IL-12B, IL-4Ralpha, and IL-10 genes and vaccine-specific immune responses (p<0.05). In addition, SNPs in the IL-1beta, TNFalpha, IL-2, IL-4, IL-10, IL-4Ralpha, and IL-12B genes were associated with variations in serum levels of immunoglobulins (IgG, IgA, IgM) and IgG isotypes (IgG1-IgG3) (p<0.05). These data suggest that genetic variations in cytokine genes can influence vaccine-induced immune responses in infants, which in turn may influence vaccine efficacy. |
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