Biology subjects

Adams, E. M.

Publications and source records attributed to Adams, E. M..

7 recordsLinked to original sources

bioRxiv2024

A Flexible Framework for Assessing the Cumulative Effects of Offshore Wind Energy Activities and Other Pressures on Aerofauna

The offshore wind energy (OSW) industry is pivotal for renewable energy transition and climate resiliency. However, OSW activities may negatively affect aerofauna, contributing to CE from human activities and natural processes. Cumulative effects assessments (CEA) are vital for informed planning and management of OSW activities during regional assessment, site selection, and site evaluation. To reduce impacts on aerofauna, OSW developments should be sited in areas that avoid or minimize cumulative effects (CE). This study presents a cohesive and flexible framework for assessing the CE from OSW activities, other human activities, and natural processes on aerofauna to support decision-making during the initial OSW planning phases. The framework uses a species-based approach, applicable to various receptors, and adapts to available information on ecology, socioeconomics, and pressures. The analytical strategy uses a CE metric to indicate the presence or magnitude of effects from all pressures on receptors. Spatially explicit optimization methods identify OSW site configurations that minimize a CE metric. The framework accommodates alternative pressure scenarios that include foreseeable future human activities and natural processes and can explore the sensitivity of the result to uncertain parameters. Given sufficient spatial information on receptor density, pressure magnitude, and cause-effect pathways, the spatial optimization algorithm can find solutions that minimize population-level impacts from CE. If this ideal standard cannot be achieved due to information gaps, alternative metrics may be used to inform the immediate decision-making process.

ecology↗

bioRxiv2024

A human induced pluripotent stem (hiPS) cell model for the holistic study of epithelial to mesenchymal transitions (EMTs)

The epithelial to mesenchymal transition (EMT) is a widely studied but poorly defined state change due to the variety of ways in which it has been characterized in cells. There is a need for reproducible cell model systems that enable the integration and comparison of different types of measured observations of cells across many distinct cellular contexts. We present human induced pluripotent stem (hiPS) cells as such a model system by demonstrating its utility through a comparative analysis of hiPS cell-EMT in 2D and 3D cell culture geometries. We developed live-imaging-based assays to directly compare examples of changes in cell function (via migration timing), molecular components (via expression of marker proteins), organization (via reorganization of cell junctions), and environment (via dynamics of basement membrane) in the same experimental system. The EMT-related changes we measured occurred earlier in 2D colonies than in 3D lumenoids, likely due to differences in the basement membrane environments associated with 2D vs. 3D initial hiPS cell culture geometries. We have made the 449 60-hour-long 3D time-lapse movies and the associated tools used for analysis and visualization open-source and easily accessible as a resource for future work in this field.

cell biology↗

bioRxiv2024

The mammalian Ire1 inhibitor, 4μ8C, exhibits broad anti-Aspergillus activity in vitro and in a treatment model of fungal keratitis.

ObjectiveThe fungal unfolded protein response consists of a two-component relay in which the ER-bound sensor, IreA, splices and activates the mRNA of the transcription factor, HacA. Previously, we demonstrated that hacA is essential for Aspergillus fumigatus virulence in a murine model of fungal keratitis (FK), suggesting the pathway could serve as a therapeutic target. Here we investigate the antifungal properties of known inhibitors of the mammalian Ire1 protein both in vitro and in a treatment model of FK. MethodsThe antifungal activity of Ire1 inhibitors was tested against conidia of several A. fumigatus isolates by a microbroth dilution assay and against fungal biofilm by XTT reduction. The influence of 48C on hacA mRNA splicing in A. fumigatus was assessed through gel electrophoresis and qRT-PCR of UPR regulatory genes. The toxicity and antifungal profile of 48C in the cornea was assessed by applying drops to uninfected or A. fumigatus-infected corneas 3 times daily starting 4 hours post-inoculation. Corneas were evaluated daily through slit-lamp imaging and optical coherence tomography, or at endpoint through histology or fungal burden quantification via colony forming units. ResultsAmong six Ire1 inhibitors screened, the endonuclease inhibitor 48C displayed the strongest antifungal profile with an apparent fungicidal action. The compound both blocked conidial germination and hyphal metabolism of A. fumigatus Af293 in the same concentration range that blocked hacA splicing and UPR gene induction (60-120 {micro}M). Topical treatment of sham-inoculated corneas with 0.5 and 2.5 mM 48C did not impact corneal clarity, but did transiently inhibit epithelialization of corneal ulcers. Relative to vehicle-treated Af293-infected corneas, treatment with 0.5 and 2.5 mM drug resulted in a 50% and >90% reduction in fungal load, respectively, the latter of which corresponded to an absence of clinical signs of infection or corneal pathology. ConclusionThe in vitro data suggest that 48C displays antifungal activity against A. fumigatus through the specific inhibition of IreA. Topical application of the compound to the murine cornea can furthermore block the establishment of infection, suggesting this class of drugs can be developed as novel antifungals that improve visual outcomes in FK patients.

microbiology↗

bioRxiv2023

Vitamin B5 Metabolism is Essential for Vacuolar and Mitochondrial Integrity and Xenobiotic Detoxification in Fungi

Fungal infections, a leading cause of mortality among eukaryotic pathogens, pose a growing global health threat due to the rise of drug-resistant strains. New therapeutic strategies are urgently needed to combat this challenge. The PCA pathway for biosynthesis of Co-enzyme A (CoA) and Acetyl-CoA (AcCoA) from vitamin B5 (pantothenic acid) has been validated as an excellent target for the development of new antimicrobials against fungi and protozoa. The pathway regulates key cellular processes including metabolism of fatty acids, amino acids, sterols, and heme. In this study, we provide genetic evidence that disruption of the PCA pathway results in a significant alteration in the susceptibility of fungi to a wide range of xenobiotics, including clinically approved antifungal drugs through alteration of vacuolar integrity and drug detoxification. The drug potentiation-mediated by genetic regulation of genes in the PCA pathway could be recapitulated using the pantazine analog PZ-2891 as well as the celecoxib derivative, AR-12 through inhibition of fungal AcCoA synthase activity. Collectively, the data validate the PCA pathway as a suitable target for enhancing the efficacy and safety of current antifungal therapies.

microbiology↗

bioRxiv2023

Aspergillus fumigatus hypoxia adaptation is critical for the establishment of fungal keratitis.

Purpose: The poor visual outcomes associated with fungal keratitis (FK) underscore a need to identify fungal pathways that can serve as novel antifungal targets. In this report, we investigated whether hypoxia develops in the FK cornea and, by extension, if fungal hypoxia adaptation is essential for virulence in this setting. Methods: C57BL/6j mice were inoculated with Aspergillus fumigatus and Fusarium solani var petroliphilum via topical overlay or instrastromal injection. At various time points post-inoculation (p.i.), animals we were injected with pimonidazole for the detection of tissue hypoxia through immunofluorescence imaging. The A. fumigatus srbA gene was deleted through Cas9-mediated homologous recombination and its virulence was assessed in the topical infection model using slit-lamp microscopy and optical coherence tomography (OCT). Results: Topical inoculation with A. fumigatus resulted in diffuse pimonidazole staining across the epithelial and endothelial layers within 6 h. Stromal hypoxia was evident by 48 h p.i., which corresponded to leukocytic infiltration. Instrastromal inoculation with either A. fumigatus or F. solani similarly led to diffuse staining patterns across all corneal cell layers. The A. fumigatus srbA deletion mutant was unable to grow at oxygen levels below 3% in vitro, and corneas inoculated with the mutant failed to develop signs of corneal opacification, inflammation or fungal burden. Conclusions: These results suggest that fungal antigen rapidly drives the development of corneal hypoxia, thus rendering fungal SrbA or related pathways essential for the establishment of infection. Such pathways may therefore serve as targets for novel antifungal intervention.

pathology↗

bioRxiv2023

Basal UPR activity in Aspergillus fumigatus regulates adaptation to nutrient stress and is critical for the establishment of corneal infection

The Aspergillus fumigatus unfolded protein response (UPR) is a two-component relay consisting of the ER-bound IreA protein, which splices and activates the mRNA of the transcription factor HacA. Spliced hacA accumulates under conditions of acute ER stress in vitro, and UPR null mutants are hypovirulent in a murine model of invasive pulmonary infection. In this report, we demonstrate that a hacA deletion mutant is completely unable to establish infection in a model of fungal keratitis, a corneal infection and an important cause of ocular morbidity and unilateral blindness worldwide. Contrary to our initial prediction, however, we demonstrate that hacA splicing is not increased above baseline conditions in the cornea, nor is the expression of genes classically associated with UPR activation, such as protein chaperones. We employed transcriptomics on wild-type and{Delta} hacA strains in gelatin media, as a proxy for the corneal environment, and found that hacA supports the expression of numerous primary and secondary metabolic processes that likely promote adaptation to nutrient limitation. Taken together, our results support a model in which the cornea, similar to growth on protein in vitro, is a source of sub-acute ER stress for A. fumigatus, but one nevertheless that requires the UPR pathway for proper adaptation. The data also suggest that this pathway could be a target for novel antifungals that improve visual outcomes for fungal keratitis patients. AUTHOR SUMMARYFungal keratitis has emerged as a leading cause of ocular morbidity and unilateral blindness worldwide. Relative to other infectious contexts, however, little is known about the fungal genes or pathways that regulate invasive growth and virulence in the corneal environment. In this report, we demonstrate that genetic disruption of the Aspergillus fumigatus unfolded protein response (UPR) abolishes the ability of the mold to establish infection in a mouse model of FK. Despite this critical role for virulence, however, we did not detect a concerted activation of the pathway beyond levels observed on standard medium, suggesting that the host environment is not an acute source of endoplasmic reticulum stress. Transcriptomic profiling of the wild-type and UPR-deficient strains under host-relevant nutrient conditions revealed a critical role for the pathway in regulating primary and secondary metabolism, cell wall biology, and mitochondrial function, all of which likely modulate fungal growth within and interactions with the host. These results expand our understanding of UPR regulation and function in this important mold pathogen and suggest the pathway could serve as a target for novel antifungals that improve visual outcomes in the setting of fungal keratitis.

microbiology↗

bioRxiv2022

Genomic and phenotypic trait variation of the opportunistic human pathogen Aspergillus flavus and its non-pathogenic close relatives

Fungal diseases affect millions of humans annually, yet fungal pathogens remain understudied. The mold Aspergillus flavus is a causative agent of both aspergillosis and fungal keratitis infections, but species closely related to A. flavus are not considered clinically relevant. To study the evolution of A. flavus pathogenicity, we examined genomic and phenotypic traits of two strains of A. flavus and three closely related non- pathogenic species: Aspergillus arachidicola (two strains), Aspergillus parasiticus (two strains), and Aspergillus nomiae (one strain). We identified over 3,000 orthologous proteins unique to A. flavus, including seven biosynthetic gene clusters present in A. flavus strains and absent in the three non-pathogenic species. We chose to characterize secondary metabolite production for all seven strains under two clinically relevant conditions, temperature and salt concentration. Temperature impacted metabolite production in all species. Conversely, we found a lack of impact of salinity on secondary metabolite production. Strains of the same species produced different metabolites. Growth under stress conditions revealed additional heterogeneity within species. Using the invertebrate model of fungal disease Galleria mellonella, we found virulence of strains of the same species varied widely, and A. flavus strains were not more virulent than strains of the non-pathogenic species. In a murine model of fungal keratitis, we observed significantly lower disease severity and corneal thickness for A. arachidicola compared to other species at 48 hrs, but not at 72 hrs. Our work identifies key phenotypic, chemical, and genomic similarities and differences between the opportunistic human pathogen A. flavus and its non-pathogenic relatives.

evolutionary biology↗