Biology subjects

Schrope, J. H.

Publications and source records attributed to Schrope, J. H..

3 recordsLinked to original sources

bioRxiv2026

Multi-omic analysis reveals nitric oxide dependent remodeling in classically activated macrophages and identifies negative regulation mediated by AKR1A1

Nitric oxide (NO*) is an important signaling molecule in many biological processes, including immune response. During response to classical activation stimuli lipopolysaccharide (LPS) and interferon-{gamma} (IFN{gamma}), macrophages generate NO* via inducible nitric oxide synthase (iNOS). To comprehensively define the effects of NO*, we applied a multi-omic strategy integrating proteomics and transcriptomics to profile murine macrophages across conditions with or without LPS/IFN{gamma}-activation, with or without iNOS expression or exogenous NO* donor treatment. The results revealed NO* has broad, yet selected and controlled, regulatory effects, playing a key role in coordinating the systematic remodeling during macrophage classical activation. Among the proteins that are most suppressed in a NO*-dependent manner, electron transport chain (ETC) is the most enriched. NO* drives complex-specific remodeling of ETC, causing selected downregulation of complex I, II, and IV, through a different combination of transcriptional and post-transcriptional mechanisms for each complex. Functionally, we found NO* is required, but not sufficient, for the strong suppression of cellular respiration upon macrophage activation. Among the most consistently upregulated proteins are many enzymes involved in redox defense. AKR1A1 was identified as a top hit. We found Akr1a1 induction requires both NO* and LPS/IFN{gamma} stimulation. The S-nitroso-CoA reductase activity of AKR1A1 mitigates NO*-driven inhibition of pyruvate dehydrogenase complex by limiting the inhibitory modifications targeting its lipoyl cofactor. Knocking out Akr1a1 causes accelerated remodeling of TCA cycle, dysregulated immunoregulatory metabolite level, and altered functional gene expression and cytokine production at later stage of immune response. Thus, the NO*-dependent upregulation of AKR1A1 forms a negative regulatory loop to fine-tune NO*-mediated metabolic and functional remodeling during immune response. Together, this work provided a systems-level map of NO*-dependent regulation, revealed the crosstalk between NO* and immune signaling, and demonstrated mechanisms providing redox adaptation and precise control of NO*s effects.

immunology↗

bioRxiv2024

Surface colonization by Flavobacterium johnsoniae promotes its survival in a model microbial community

Flavobacterium johnsoniae is a ubiquitous soil and rhizosphere bacterium, but despite its abundance, the factors contributing to its success in communities are poorly understood. Using a model microbial community, The Hitchhikers Of the Rhizosphere (THOR), we determined the effects of colonization on fitness of F. johnsoniae in the community. Insertion sequencing (INSeq), a massively parallel transposon mutant screen, on sterile sand identified 25 genes likely to be important for surface colonization. We constructed in-frame deletions of nine candidate genes predicted to be involved in cell membrane biogenesis, motility, signal transduction, and transport of amino acids and lipids. All mutants poorly colonized sand, glass, and polystyrene and produced less biofilm than the wild type, indicating the importance of the targeted genes in surface colonization. Eight of the nine colonization-defective mutants were also unable to form motile biofilms, or zorbs, thereby suggesting that the affected genes play a role in group movement and linking stationary and motile biofilm formation genetically. Furthermore, we showed that deletion of colonization genes in F. johnsoniae affected its behavior and survival in THOR on surfaces, suggesting that the same traits are required for success in a multispecies microbial community. Our results provide insight into the mechanisms of surface colonization by F. johnsoniae and form the basis for further understanding its ecology in the rhizosphere. IMPORTANCEMicrobial communities direct key environmental processes through multispecies interactions. Understanding these interactions is vital for manipulating microbiomes to promote health in human, environmental, and agricultural systems. However, microbiome complexity can hinder our understanding of the underlying mechanisms in microbial community interactions. As a first step towards unraveling these interactions, we explored the role of surface colonization in microbial community interactions using THOR, a genetically tractable model community of three bacterial species, Flavobacterium johnsoniae, Pseudomonas koreensis, and Bacillus cereus. We identified F. johnsoniae genes important for surface colonization in solitary conditions and in the THOR community. Understanding the mechanisms that promote success of bacteria in microbial communities brings us closer to targeted manipulations to achieve outcomes that benefit agriculture, the environment, and human health.

microbiology↗

bioRxiv2023

Liquid-liquid interface microchannels with tunable mechanical properties mimic tissue deformations during neutrophil interstitial migration in vivo

Leukocytes navigate through interstitial spaces resulting in deformation of both the motile leukocytes and surrounding cells. Creating an in vitro system that models the deformable cellular environment encountered in vivo has been challenging. Here, we engineer microchannels with a liquid-liquid interface that exerts confining pressures (200-3000 Pa) similar to cells in tissues, and, thus, is deformable by cell generated forces. Consequently, the balance between migratory cell-generated and interfacial pressures determines the degree of confinement. Pioneer cells that first contact the interfacial barrier require greater deformation forces to forge a path for migration, and as a result migrate slower than trailing cells. Critically, resistive pressures are tunable by controlling the curvature of the liquid interface, which regulates motility. By granting cells autonomy in determining their confinement, and tuning environmental resistance, interfacial deformations are made to match those of surrounding cells in vivo during interstitial neutrophil migration in a larval zebrafish model. We discover that, in this context, neutrophils employ a bleb-based mechanism of force generation to deform a barrier exerting cell-scale confining pressures. Significance StatementImmune cells sense physical forces provided by surrounding cellular tissues to regulate their motility. Here, we introduce the use of liquid-liquid interfaces to model forces exerted by surrounding cells during interstitial motility in vivo. Neutrophils interacting with the interface employ a bleb-based mechanism of force generation to induce interfacial deformation. This work furthers our understanding of the mechanisms employed by immune cells to traverse through deformable barriers akin to cells in the body, and introduces a pioneering technology enabling the study of cell interaction with soft materials.

bioengineering↗