Biology subjects

Hung, L. Y.

Publications and source records attributed to Hung, L. Y..

4 recordsLinked to original sources

bioRxiv2024

Perforin-2 is dispensable for host defense against Aspergillus fumigatus and Candida albicans

Myeloid phagocytes are essential for antifungal immunity against pulmonary Aspergillus fumigatus and systemic Candida albicans infections. However, the molecular mechanisms underlying fungal clearance by phagocytes remain incompletely understood. In this study, we investigated the role of perforin-2 (Mpeg1) in antifungal immunity. We found that Mpeg1-/- mice generated on a mixed C57BL/6J-DBA/2 background exhibited enhanced survival, reduced lung fungal burden, and greater neutrophil fungal killing activity compared to wild-type C57BL/6J (B6) mice, suggesting that perforin-2 may impair antifungal immune responses. However, when we compared Mpeg1-/- mice with co-housed Mpeg+/+ littermate controls, these differences were no longer observed, indicating that initial findings were likely influenced by differences in the murine genetic background or the microbiota composition. Furthermore, perforin-2 was dispensable for antifungal immunity during C. albicans bloodstream infection. These results suggest that perforin-2 is not essential for host defense against fungal infections in otherwise immune competent mice and highlight the importance of generating co-housed littermate controls to minimize murine genetic and microbiota-related factors in studies of host defense mechanisms. IMPORTANCEAspergillus fumigatus is the leading cause of invasive aspergillosis (IA), which is associated with significant mortality, particularly in immunocompromised patients such as those with acute leukemia or undergoing hematopoietic stem cell transplants, where death rates reach 40-50% despite standard care. Treatments for IA remain limited and resistance to antifungals is emerging, leading the World Health Organization to recently classify A. fumigatus as a critical priority fungal pathogen. A greater understanding of how the immune system clears A. fumigatus could lead to host-directed therapies that could complement our current armamentarium of antifungal drugs and improve patient outcomes. Our findings reveal that perforin-2 is not essential for antifungal immunity against A. fumigatus in otherwise immune-competent mice and underscore the necessity of using co-housed littermate controls to avoid confounding factors in immunological studies.

immunology↗

bioRxiv2021

3D Mapping of Neurofibrillary Tangle Burden in the Human Medial Temporal Lobe

Tau protein neurofibrillary tangles (NFT) are closely linked to neuronal/synaptic loss and cognitive decline in Alzheimers disease (AD) and related dementias. Our knowledge of the pattern of NFT progression in the human brain, critical to the development of imaging biomarkers and interpretation of in vivo imaging studies in AD, is based on conventional 2D histology studies that only sample the brain sparsely. To address this limitation, ex vivo MRI and dense serial histological imaging in 18 human medial temporal lobe (MTL) specimens were used to construct 3D quantitative maps of NFT burden in the MTL at individual and group levels. These maps reveal significant variation in NFT burden along the anterior-posterior axis. While early NFT pathology is thought to be confined to the transentorhinal region, we find similar levels of NFT burden in this region and other MTL subregions, including amygdala, temporopolar cortex, and subiculum/CA1.

neuroscience↗

bioRxiv2018

LINGO3 interacts with Trefoil factor 2 to enforce mucosal barrier integrity and drive tissue repair during colitis

Mucosal epithelia are constantly exposed to damaging stimuli from mechanical, chemical, or biologic entities, and depend on rapid repair mechanisms to maintain tissue homeostasis and immunological quiescence. The reparative cytokine Trefoil factor 2 (TFF2) serves to enforce mucosal barrier integrity, but whether TFF2 receptor(s) exist is controversial. Herein, we demonstrate leucine rich repeat and immunoglobulin like domain containing nogo receptor interacting protein 3 (LINGO3) is a necessary transmembrane component for TFF2-mediated ERK signaling, proliferation, and recovery of trans-epithelial resistance of primary epithelia during wound healing. Human respiratory and intestinal epithelia express LINGO3 and mice lacking Lingo3 have impaired intestinal barrier function and fail to recover from DSS-induced colitis. Compared to wild-type controls, LINGO3 deficiency impairs both crypt regeneration and expression of the intestinal stem cell marker Lgr5. Importantly, Lingo3-/- mice display a phenotype similar to that previously reported for Tff2 deficiency, with increased paracellular permeability, and significant accumulation of mucosal CD4+ TH1 cells expressing IFN{gamma}+ TNF+ even under steady-state conditions. Combined, these data reveal a previously unrecognized role for LINGO3 as a putative TFF2 receptor that regulates mucosal barrier integrity and GI inflammation.\n\nSignificanceIntestinal epithelial cells (IEC) are necessary for maintenance of homeostasis, resistance to infectious organisms, and overall organismal health. When injured the IEC and the underlying stroma and progenitor cell pool undergo restitutive and regenerative processes driven by the reparative cytokine Trefoil factor 2 (TFF2). This report identifies a novel receptor component for TFF2 signaling expressed on both human and mouse epithelial cells that is necessary for barrier integrity at the steady state and during colitic disease. The discovery of a novel TFF2-LINGO3 axis sheds new light on the processes controlling tissue repair, restitution, and regeneration at the mucosal interface.

cell biology↗

bioRxiv2018

TFF3 is a ligand for LINGO2 that de-represses EGFR to control disease outcome during colitis and gastrointestinal nematode infection

Intestinal epithelial cells (IEC) comprise diverse lineages that serve distinct roles necessary for regulation of nutrient absorption, regeneration, immunity, and homeostasis1,2. Goblet cells secrete Trefoil factor 3 (TFF3) to maintain mucus viscosity and drive mucosal healing by inhibiting cell death and influencing tight junction protein expression3. However, whether TFF3 signaling relies upon conventional ligand-receptor interactions has been unclear for decades. This study demonstrates that the orphan transmembrane protein leucine rich repeat receptor and nogo-interacting protein 2 (LINGO2) immunoprecipitates with TFF3, that LINGO2 and TFF3 co-localize at the IEC cell surface, and that TFF3/LINGO2 interactions block IEC apoptosis. Loss of function studies show that TFF3-driven STAT3 and EGFR activation are both LINGO2 dependent. Importantly, we demonstrate that TFF3 disrupts LINGO2/EGFR interactions that normally restrict EGFR activity, resulting in enhanced EGFR signaling. Excessive EGFR activation in Lingo2 gene deficient mice exacerbates colitic disease and accelerates host resistance to parasitic nematodes, whereas TFF3 deficiency results in host susceptibility. Thus, our data demonstrating that TFF3 functions through a previously unrecognized ligand-receptor interaction with LINGO2 to de-repress LINGO2-dependent inhibition of EGFR activation provides a novel conceptual framework explaining how TFF3-mediates mucosal wound healing through enhanced activation of the EGFR pathway.

cell biology↗