Application of the adverse outcome pathway framework to genotoxic modes of action

In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114–134, 2020. © 2019 Wiley Periodicals, Inc.     

Aktuelles zum Thema Latex-Allergie

Zusammenfassung Die Typ I-Allergien gegen Latex sind in den vergangenen Jahren zu einem zunehmenden berufsdermatologischen Problem geworden, zumal mindestens 10% der Angestellten im Gesundheitswesen betroffen sind. In der Dermatologischen Klinik der Universit?t Erlangen-Nürnberg stieg die Anzahl der j?hrlich diagnostizierten Patienten mit Latexallergien von 1989 bis 1995 auf das 12fache, wobei der Anteil der schweren, generalisierten Formen der Erkrankung von 10,7% (1989/1990) auf 44% (1994/1995) zunahm. Unter den m?glichen Ausl?sern der Latexallergie (wasserl?sliche Proteine mit Molekulargewichten von 2 bis 200 kD) sind mindestens 5 Hauptproteine mit bereits bekannter Prim?rstruktur zu berücksichtigen. Zus?tzlich gibt es Hinweise für Markerproteine, die in bestimmten Risikogruppen geh?uft zur Ausl?sung spezifischer IgE-Antik?rper führen (z.B. 46 kD-Protein in medizinischen Berufen, 14,6 kD- und 27 kD-Proteine bei Kindern mit Spina bifida). Das Vorkommen von Kreuzreaktionen zwischen Latex und unterschiedlichen Früchten (besonders Avocado, Kiwi, Banane, E?kastanie) bei 60 bis 70% der Latexallergiker ist bei der allergologischen Abkl?rung und Beratung dieser Patienten zu beachten. Wesentliche Aspekte der Prophylaxe umfassen die konsequente Umstellung medizinischer Einrichtungen auf ungepuderte Latexhandschuhe mit niedrigem Proteingehalt. Eine Zusammenstellung von OP- und Untersuchungshandschuhen, welche Angaben über die von uns ermittelten Proteinkonzentrationen (modifizierte Lowry-Methode und Hochdruck-Flüssigkeits-Chromatographie, HPLC) enth?lt, soll ein Leitfaden bei der Auswahl allergologisch geeigneter Handschuhe sein. Eingegangen am 10. August 1996 Angenommen am 21. August 1996     

Characterization and screening of bacteria from rhizosphere of maize grown in Indonesian and Pakistani soils

Thirty rhizobacteria isolated from maize grown in Pakistani and Indonesian soils were evaluated for their morphological characteristics, nitrogen fixation, P-solubilization, indole acetic acid (IAA) and siderophores production. Nitrogenase activity was detected in nineteen isolates ranging from 21.8-3624 n moles C2H4 produced/h/mg protein. Most of the isolates produced IAA, ten were capable of siderophore production while four were P-solubilizers. Ultrastructural studies of Pseudomonas sp. F14 indicated characteristic rhizospheric colonization within 48 h that was observed to change considerably with the passage of time from few bacteria to micro colonies. Random amplified polymorphic DNA (RAPD) analysis of 30 bacterial strains using 30 oligonucleotide primers resulted in considerable level of genetic diversity, with genetic distance ranging from 2-16%. Indonesian isolates were found to be more diverse as compared to Pakistani isolates. The characterization and screening of rhizobacteria of maize rhizosphere has helped in selection of isolates F7, LS-1, 3.1.1.C, F2, F3 and F13 as superior strains for use as bioinoculant. Moreover isolate F14 identified, as Pseudomonas fulgida by partial 16S rRNA sequence analysis is a novel strain regarding its tremendous potentials for inoculum production to enhance the yield of maize.     

Use of subtractive hybridization to identify a diagnostic probe for a cystic fibrosis epidemic strain of Pseudomonas aeruginosa

A multiresistant strain of Pseudomonas aeruginosa is widespread among cystic fibrosis (CF) patients attending clinics in Liverpool, United Kingdom. Suppression subtractive hybridization was used to identify sequences present in the Liverpool CF epidemic strain but absent from strain PAO1. Using dot blot and PCR amplification assays, the prevalence of such sequences among a panel of CF isolates was determined. Several sequences were found only in the Liverpool epidemic strain. Some sequences were present in the Liverpool epidemic strain and in a minority of other isolates, including sequences with homology to genes implicated in O6 serotype and siderophore production. The Liverpool epidemic strain and 81% of nonepidemic isolates contained a sequence identified as part of the PAGI-1 genomic island. Other strains implicated in epidemic spread, which were from Manchester, United Kingdom, and Melbourne, Australia, were also screened. None of the sequences identified was present in the Manchester strain. However, one of two Melbourne strains contained some of the sequences found in the Liverpool epidemic strain. All isolates implicated in epidemic spread and 76% of sporadic isolates contained the exoS gene. A sequence present in all isolates of the Liverpool epidemic strain was used to develop a diagnostic PCR test for identification of the strain from colonies or directly from sputum samples.     

Replicative multivirus infection with cytomegalovirus, herpes simplex virus 1, and parvovirus B19, and latent Epstein-Barr virus infection in the synovial tissue of a psoriatic arthritis patient.

BACKGROUND: Psoriatic arthropathy occurs as complicating feature in about 5-7% of psoriasis patients. Infectious mechanisms including viral antigens have been suggested by serologic data as CD8 T cellular specifity towards viral epitopes. OBJECTIVE AND RESULTS: We here reported a case of a 32-year-old male psoriatic arthritis patient, where we could demonstrate simultaneous infection with cytomegalovirus (CMV), herpes simplex virus type I (HSV1) and parvovirus B19 (B19), as well as latent Epstein-Barr virus (EBV) infection within the synovial tissue by immunohistochemistry (CMV, parvovirus B19, HSV1, EBV-LMP) and DNA-in situ-hybridization (CMV). Serologic examination revealed positive EBV and parvovirus B19-IgG-antibodies, but no antibody response to HSV1 and CMV. CONCLUSION: This case is of special interest, since replicative viral infections have not yet been demonstrated localised in the psoriatic arthritis synovia. Thus, with particular regard to the limited information of the serologic data and the possible need of immuno suppressive therapy direct synovial testing for viral antigenes may be considered in psoriatic arthritis patients.     

What Are the Maternal Factors that Potentially Intervenes in the Nutritional Composition of Human Milk?

Background: To evaluate the potential factors associated with the nutritional composition of human milk of puerperal women. Methods: cross-sectional study, conducted between March 2016 and August 2017, with 107 women, selected in a Tertiary Health Care Tertiary Health Facility of the Unified Health System (SUS) in the Municipality of Rio de Janeiro. Data were collected two months after delivery. The dependent variable of the study was the nutritional composition of human milk. We divided the independent variables into hierarchical levels: distal (age, schooling, parity and pregestational nutritional status), intermediate (number of prenatal visits and gestational weight gain) and proximal (alcohol consumption, smoking, diabetes mellitus and hypertension). For data analysis, we applied the multiple linear regression, centered on the hierarchical model. Only the variables associated with the nutritional composition of breast milk remained in the final model at a 5% level of significance. Results: The nutritional composition of human milk yielded by women with pregestational overweight, smokers and hypertensive had higher amounts of lipids and energy. Conversely, women with gestational weight gain below the recommended had lower amounts of these components. Conclusion: The evaluation of factors associated with the nutritional composition of human milk is extremely important to assist post-partum care practices. In this study, we observed that lipid and energy contents were associated to pregestational nutritional status, gestational weight gain, smoking and hypertension.     

Characterization of an Agarophyton chilense Oleoresin Containing PPARγ Natural Ligands with Insulin-Sensitizing Effects in a C57Bl/6J Mouse Model of Diet-Induced Obesity and Antioxidant Activity in Caenorhabditis elegans

The biomedical potential of the edible red seaweed Agarophyton chilense (formerly Gracilaria chilensis) has not been explored. Red seaweeds are enriched in polyunsaturated fatty acids and eicosanoids, which are known natural ligands of the PPARγ nuclear receptor. PPARγ is the molecular target of thiazolidinediones (TZDs), drugs used as insulin sensitizers to treat type 2 diabetes mellitus. Medical use of TZDs is limited due to undesired side effects, a problem that has triggered the search for selective PPARγ modulators (SPPARMs) without the TZD side effects. We produced Agarophyton chilense oleoresin (Gracilex^®), which induces PPARγ activation without inducing adipocyte differentiation, similar to SPPARMs. In a diet-induced obesity model of male mice, we showed that treatment with Gracilex^® improves insulin sensitivity by normalizing altered glucose and insulin parameters. Gracilex^® is enriched in palmitic acid, arachidonic acid, oleic acid, and lipophilic antioxidants such as tocopherols and β-carotene. Accordingly, Gracilex^® possesses antioxidant activity in vitro and increased antioxidant capacity in vivo in Caenorhabditis elegans. These findings support the idea that Gracilex^® represents a good source of natural PPARγ ligands and antioxidants with the potential to mitigate metabolic disorders. Thus, its nutraceutical value in humans warrants further investigation.     

Chimeric antigen receptor-modified human regulatory T cells that constitutively express IL-10 maintain their phenotype and are potently suppressive

Clinical trials of Treg therapy in transplantation are currently entering phases IIa and IIb, with the majority of these employing polyclonal Treg populations that harbor a broad specificity. Enhancing Treg specificity is possible with the use of chimeric antigen receptors (CARs), which can be customized to respond to a specific human leukocyte antigen (HLA). In this study, we build on our previous work in the development of HLA-A2 CAR-Tregs by further equipping cells with the constitutive expression of interleukin 10 (IL-10) and an imaging reporter as additional payloads. Cells were engineered to express combinations of these domains and assessed for phenotype and function. Cells expressing the full construct maintained a stable phenotype after transduction, were specifically activated by HLA-A2, and suppressed alloresponses potently. The addition of IL-10 provided an additional advantage to suppressive capacity. This study therefore provides an important proof-of-principle for this cell engineering approach for next-generation Treg therapy in transplantation.