Biology subjects

Schoen, T. J.

Publications and source records attributed to Schoen, T. J..

4 recordsLinked to original sources

bioRxiv2026

Rhomboid protease Rhbdl2 regulates macrophage recruitment and wound regeneration in zebrafish

Tissue regeneration requires tight control of immune cell behavior, yet the mechanisms that restrain immune-driven regenerative responses remain poorly defined. Here, we identify the rhomboid intramembrane serine protease Rhbdl2 as a critical regulator of regeneration in zebrafish. We generated rhbdl2 mutants by CRISPR Cas9 and found that it does not affect normal development, but triggers enhanced regenerative growth following injury, accompanied by increased macrophage accumulation at the wound site, which is accompanied by increased early apoptosis and proliferation. Proteomic analyses reveal increased Rac2 protein levels in rhbdl2 mutants, indicating dysregulated immune signaling. Functionally, Rac2 morpholino oligonucleotides mediated knockdown in rhbdl2 mutant larvae suppresses the elevated macrophage recruitment and enhanced tissue regenerative phenotype. Together, these findings uncover Rhbdl2 as an immune checkpoint that constrains macrophage driven enhanced regeneration, with vast implications for inflammatory disease, fibrosis, and tumor immune interactions.

immunology↗

bioRxiv2023

PTP1B phosphatase puts a brake on iPSC-derived neutrophil motility and antimicrobial function

Neutrophils are rapidly recruited to sites of infection and are critical for pathogen clearance. Neutropenic patients are at high risk for fungal and bacterial infections and can benefit from granulocyte transfusion therapy. Human induced pluripotent stem cells (iPSCs) could provide a robust source of neutrophil-like cells for infusion as they can be generated in large quantities and do not require a donor. However, dampened intracellular signaling limits their cellular activation and response. Here, we show that we can engineer iPSC-derived neutrophils (iNeutrophils) for enhanced motility and anti-microbial functions. Deletion of the PTP1B phosphatase increased iNeutrophil PI3K and ERK signaling and was associated with increased F-actin polymerization, cell migration and phagocytosis. PTP1B deletion also increased production of inflammatory cytokines, including the neutrophil chemoattractant IL-8. Furthermore, PTP1B-KO iNeutrophils displayed a highly activated morphology and were more responsive to the fungal pathogen Aspergillus fumigatus. KO iNeutrophils efficiently migrated to and swarmed hyphae resulting in inhibition of fungal growth. Taken together, deletion of the PTP1B phosphatase removes the "brakes" on iPSC-derived intracellular signaling and neutrophil function. Key pointsDeletion of PTP1B increases iPSC-derived neutrophil intracellular signaling to improve motility and phagocytosis. Deletion of PTP1B enhances iPSC-derived neutrophil swarming response and ability to inhibit fungal growth.

immunology↗

bioRxiv2023

Aspergillus fumigatus transcription factor ZfpA regulates hyphal development and alters susceptibility to antifungals and neutrophil killing during infection

Hyphal growth is essential for host colonization during Aspergillus infection. The transcription factor ZfpA regulates A. fumigatus hyphal development including branching, septation, and cell wall composition. However, how ZfpA affects fungal growth and susceptibility to host immunity during infection has not been investigated. Here, we use the larval zebrafish-Aspergillus infection model and primary human neutrophils to probe how ZfpA affects A. fumigatus pathogenesis and response to antifungal drugs in vivo. ZfpA deletion promotes fungal clearance and attenuates virulence in wild-type hosts and this virulence defect is abrogated in neutrophil-deficient zebrafish. ZfpA deletion also increases susceptibility to human neutrophils ex vivo while overexpression impairs fungal killing. Overexpression of ZfpA confers protection against the antifungal caspofungin by increasing chitin synthesis during hyphal development, while ZfpA deletion reduces cell wall chitin and increases caspofungin susceptibility in neutrophil-deficient zebrafish. These findings suggest a protective role for ZfpA activity in resistance to the innate immune response and antifungal treatment during A. fumigatus infection. Author SummaryAspergillus fumigatus is a common environmental fungus that can infect immunocompromised people and cause a life-threatening disease called invasive aspergillosis. An important step during infection is the development of A. fumigatus filaments known as hyphae. A. fumigatus uses hyphae to acquire nutrients and invade host tissues, leading to tissue damage and disseminated infection. In this study we report that a regulator of gene transcription in A. fumigatus called ZfpA is important for hyphal growth during infection. We find that ZfpA activity protects the fungus from being killed by innate immune cells and decreases the efficacy of antifungal drugs during infection by regulating construction of the cell wall, an important protective layer for fungal pathogens. Our study introduces ZfpA as an important genetic regulator of stress tolerance during infection that protects A. fumigatus from the host immune response and antifungal drugs.

microbiology↗

bioRxiv2019

Imaging invasive fungal growth and inflammation in NADPH oxidase-deficient zebrafish

Neutrophils are primary cells of the innate immune system that generate reactive oxygen species (ROS) and mediate host defense. Deficient phagocyte NADPH oxidase (PHOX) function leads to chronic granulomatous disease (CGD) that is characterized by invasive infections including those by the generally non-pathogenic fungus Aspergillus nidulans. The role of neutrophil ROS in this specific host-pathogen interaction remains unclear. Here, we exploit the optical transparency of zebrafish to image the effects of neutrophil ROS on invasive fungal growth and neutrophil behavior in response to Aspergillus nidulans. In a wild-type host, A. nidulans germinates rapidly and elicits a robust inflammatory response with efficient fungal clearance. PHOX-deficient larvae have increased susceptibility to invasive A. nidulans infection despite robust neutrophil infiltration. Expression of p22phox specifically in neutrophils does not affect fungal germination but instead limits the area of fungal growth and excessive neutrophil inflammation and is sufficient to restore host survival in p22phox-deficient larvae. These findings suggest that neutrophil ROS limits invasive fungal growth and has immunomodulatory activities that contribute to the specific susceptibility of PHOX-deficient hosts to invasive A. nidulans infection.

cell biology↗