Mitochondrial reactive oxygen species as major effectors of antimicrobial immunity

This is the final version. Available on open access from Public Library of Science via the DOI in this recordMedical Research Council (MRC

Issues of financial assurance of economy greening in the regions

The relevance of the analyzed issue is caused by the need to internalize environmental externalities in the modern world. The purpose of the article is to examine the issue of financial support of the green economy using the example of the regions included in the Volga Federal District (VFD). The leading methods to the study of this issue is a comparative analysis of environmental taxes and charges in Russia and countries of the European Union (EU) and the analysis of environmental problems in the regions of the Volga Federal District, which allow identifying the shortcomings of the existing environmental payment system and proposing measures to modernize the system of financial support of the green economy. The key shortcomings of the existing environmental payment system: low rates of environmental payments; the inappropriate use of funds received from environmental payments; concentration of 97% of revenues from environmental payments in the federal budget. The contents of the article may be helpful for public authorities of general and special competence to develop the principal directions of environmental policy and plan activities aimed at improving the green economy. © 2016 Shekhova et al

Mitochondrial Reactive Oxygen Species Regulate Immune Responses of Macrophages to Aspergillus fumigatus

This is the final version. Available on open access from Frontiers Media via the DOI in this recordData Availability Statement: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.Reactive Oxygen Species (ROS) are highly reactive molecules that can induce oxidative stress. For instance, the oxidative burst of immune cells is well known for its ability to inhibit the growth of invading pathogens. However, ROS also mediate redox signalling, which is important for the regulation of antimicrobial immunity. Here, we report a crucial role of mitochondrial ROS (mitoROS) in antifungal responses of macrophages. We show that mitoROS production rises in murine macrophages exposed to swollen conidia of the fungal pathogen Aspergillus fumigatus compared to untreated macrophages, or those treated with resting conidia. Furthermore, the exposure of macrophages to swollen conidia increases the activity of complex II of the respiratory chain and raises mitochondrial membrane potential. These alterations in mitochondria of infected macrophages suggest that mitoROS are produced via reverse electron transport (RET). Significantly, preventing mitoROS generation via RET by treatment with rotenone, or a suppressor of site IQ electron leak, S1QEL1.1, lowers the production of pro-inflammatory cytokines TNF-α and IL-1β in macrophages exposed to swollen conidia of A. fumigatus. Rotenone and S1QEL1.1 also reduces the fungicidal activity of macrophages against swollen conidia. Moreover, we have established that elevated recruitment of NADPH oxidase 2 (NOX2, also called gp91phox) to the phagosomal membrane occurs prior to the increase in mitoROS generation. Using macrophages from gp91phox mice, we have further demonstrated that NOX2 is required to regulate cytokine secretion by RET-associated mitoROS in response to infection with swollen conidia. Taken together, these observations demonstrate the importance of RET-mediated mitoROS production in macrophages infected with A. fumigatus.Medical Research Council (MRC)Wellcome Trus

Non-canonical signalling mediates changes in fungal cell wall PAMPs that drive immune evasion

This is the final version. Available from the publisher via the DOI in this record.To colonise their host, pathogens must counter local environmental and immunological challenges. Here, we reveal that the fungal pathogen Candida albicans exploits diverse host-associated signals to promote immune evasion by masking of a major pathogen-associated molecular pattern (PAMP), β-glucan. Certain nutrients, stresses and antifungal drugs trigger β-glucan masking, whereas other inputs, such as nitrogen sources and quorum sensing molecules, exert limited effects on this PAMP. In particular, iron limitation triggers substantial changes in the cell wall that reduce β-glucan exposure. This correlates with reduced phagocytosis by macrophages and attenuated cytokine responses by peripheral blood mononuclear cells. Iron limitation-induced β-glucan masking depends on parallel signalling via the iron transceptor Ftr1 and the iron-responsive transcription factor Sef1, and the protein kinase A pathway. Our data reveal that C. albicans exploits a diverse range of specific host signals to trigger protective anticipatory responses against impending phagocytic attack and promote host colonisation.Medical Research Council (MRC)European CommissionWellcome Trus

Non-canonical signalling mediates changes in fungal cell wall PAMPs that drive immune evasion

Data Availability The authors declare that the data supporting the findings of this study are available within the paper (and its supplementary information files). Acknowledgements We are grateful to Raif Yuecel, Linda Duncan, Kimberley Sim and Ailsa Laird in the Iain Fraser Cytometry Centre, and to Kevin MacKenzie, Debbie Wilkinson, Gillian Milne and Lucy Wight in our Microscopy and Histology Core Facility for their superb support. We thank Katja Schafer and Angela Lopez for help with the design of primers and for providing CRISPR-Cas9 protocols for mutant construction. We also thank our colleagues in the Candida community, and in particular Jan Quinn, Guanghua Huang, Suzanne Noble, Karl Kuchler, Patrick van Dijck, Rich Calderone and Malcolm Whiteway for providing strains used in this study. This work was funded by a programme grant from the UK Medical Research Council [www.mrc.ac.uk: MR/M026663/1], and by PhD studentships from the University of Aberdeen to AP, DL. The work was also supported by the Medical Research Council Centre for Medical Mycology and the University of Aberdeen [MR/N006364/1], by the European Commission [FunHoMic: H2020-MSCA-ITN-2018-812969], and by the Wellcome Trust via Investigator, Collaborative, Equipment, Strategic and Biomedical Resource awards [www.wellcome.ac.uk: 075470, 086827, 093378, 097377, 099197, 101873, 102705, 200208]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Hypoxia Promotes Immune Evasion by Triggering β-glucan Masking on the Candida albicans Cell Surface via Mitochondrial and cAMP-Protein Kinase A Signaling

We are very grateful to the members of our Iain Fraser Cytometry Centre and Microscopy and Histology Core Facility for their superb help, advice and support. We also thank our generous colleagues in the Candida community, and in particular Ana Traven, Jan Quinn, Guanghua Huang, Suzanne Noble, Donna MacCallum, Liz Johnson, Karl Kuchler, Patrick van Dijck, Rich Calderone and Malcolm Whiteway for providing strains used in this study. This work was funded by grants from the UK Medical Research Council [www.mrc.ac.uk], to AJPB, NARG, LPE, MN (MR/M026663/1), and by PhD studentships from the University of Aberdeen to AP, DL. The work was also supported by the Wellcome Trust [www.wellcome.ac.uk], NARG, GDB, AJPB (097377) and GDB (102705); and by the Medical Research Council Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Age difference of patients with and without invasive aspergillosis: a systematic review and meta-analysis

BACKGROUND: Invasive Aspergillosis (IA) is a life-threatening fungal disease with significant mortality rates. Timely diagnosis and treatment greatly enhance patient outcomes. This study aimed to explore the association between patient age and the development of IA, as well as the potential implications for risk stratification strategies. METHODS: We searched National Center for Biotechnology Information (NCBI) databases for publications until October 2023 containing age characteristics of patients with and without IA. A random-effects model with the application of inverse-variance weighting was used to pool reported estimates from each study, and meta-regression and subgroup analyses were utilized to assess sources of heterogeneity. RESULTS: A systematic review was conducted, resulting in the inclusion of 55 retrospective observational studies with a total of 13,983 patients. Meta-analysis revealed that, on average, patients with IA were approximately two and a half years older (95% Confidence Interval [CI] 1.84-3.31 years; I(2) = 26.1%) than those without the disease (p < 0.0001). No significant moderators could explain the observed heterogeneity in age difference. However, subgroup analysis revealed that age differences were more pronounced within particular patient groups compared to others. For example, patients with and without IA who had primary severe lung infections exhibited a greater difference in mean age than other patient cohorts. CONCLUSIONS: Further research, such as individual patient data meta-analysis, is necessary to better understand the potential relationship between increasing age and the likelihood of IA. Improved risk stratification strategies based on patient age could potentially enhance the early detection and treatment of IA, ultimately improving patient outcomes.Published version, accepted version, submitted versionRDUH can access the full-text of this article by clicking on the 'Additional Link' above and logging in with NHS OpenAthens if prompted

Hypoxia Promotes Immune Evasion by Triggering beta-Glucan Masking on the Candida albicans Cell Surface via Mitochondrial and cAMP-Protein Kinase A Signaling

Contains fulltext : 200161.pdf (publisher's version ) (Open Access)Organisms must adapt to changes in oxygen tension if they are to exploit the energetic benefits of reducing oxygen while minimizing the potentially damaging effects of oxidation. Consequently, organisms in all eukaryotic kingdoms display robust adaptation to hypoxia (low oxygen levels). This is particularly important for fungal pathogens that colonize hypoxic niches in the host. We show that adaptation to hypoxia in the major fungal pathogen of humans Candida albicans includes changes in cell wall structure and reduced exposure, at the cell surface, of beta-glucan, a key pathogen-associated molecular pattern (PAMP). This leads to reduced phagocytosis by murine bone marrow-derived macrophages and decreased production of IL-10, RANTES, and TNF-alpha by peripheral blood mononuclear cells, suggesting that hypoxia-induced beta-glucan masking has a significant effect upon C. albicans-host interactions. We show that hypoxia-induced beta-glucan masking is dependent upon both mitochondrial and cAMP-protein kinase A (PKA) signaling. The decrease in beta-glucan exposure is blocked by mutations that affect mitochondrial functionality (goa1Delta and upc2Delta) or that decrease production of hydrogen peroxide in the inner membrane space (sod1Delta). Furthermore, beta-glucan masking is enhanced by mutations that elevate mitochondrial reactive oxygen species (aox1Delta). The beta-glucan masking defects displayed by goa1Delta and upc2Delta cells are suppressed by exogenous dibutyryl-cAMP. Also, mutations that inactivate cAMP synthesis (cyr1Delta) or PKA (tpk1Delta tpk2Delta) block the masking phenotype. Our data suggest that C. albicans responds to hypoxic niches by inducing beta-glucan masking via a mitochondrial cAMP-PKA signaling pathway, thereby modulating local immune responses and promoting fungal colonization.IMPORTANCE Animal, plant, and fungal cells occupy environments that impose changes in oxygen tension. Consequently, many species have evolved mechanisms that permit robust adaptation to these changes. The fungal pathogen Candida albicans can colonize hypoxic (low oxygen) niches in its human host, such as the lower gastrointestinal tract and inflamed tissues, but to colonize its host, the fungus must also evade local immune defenses. We reveal, for the first time, a defined link between hypoxic adaptation and immune evasion in C. albicans As this pathogen adapts to hypoxia, it undergoes changes in cell wall structure that include masking of beta-glucan at its cell surface, and it becomes better able to evade phagocytosis by innate immune cells. We also define the signaling mechanisms that mediate hypoxia-induced beta-glucan masking, showing that they are dependent on mitochondrial signaling and the cAMP-protein kinase pathway. Therefore, hypoxia appears to trigger immune evasion in this fungal pathogen