Biology subjects

Stevenson, H. L.

Publications and source records attributed to Stevenson, H. L..

4 recordsLinked to original sources

bioRxiv2026

LiverHomo: An Integrated and Interactive Human Liver Single-Cell Atlas with Protein Interaction and Cell-Cell Communication Networks

LiverHomo is an integrated cell atlas developed from publicly available human liver single-cell RNA sequencing (scRNA-seq) datasets spanning healthy and diverse liver disease contexts. While several single-cell resources for the human liver are available, LiverHomo provides broad disease coverage and extends transcriptomic exploration through the integration of protein-protein interaction (PPI) networks and cell-cell interactions. LiverHomo provides an interactive web portal (https://liverhomo.org) for exploring cellular composition, gene expression, differentially expressed genes, Gene Ontology annotations, cell-cell interactions, and context-specific PPI networks across diseases and cell types. To facilitate intuitive access to these multidimensional data, the portal incorporates Ask LiverHomo, a natural-language assistant that interprets user queries and directs users to relevant analyses and visualizations. Interactive histograms, violin plots, network visualizations, and metadata exploration enable users to examine the atlas at cellular, transcriptomic, and protein-interaction levels, while the underlying data are readily accessible for further analysis. Together, LiverHomo provides an integrated and accessible resource for investigating cellular and molecular alterations across human liver health and disease.

bioinformatics↗

bioRxiv2025

Amniotic Fluid Reduces Liver Fibrosis By Attenuating Hepatic Stellate Cell Activation

Regardless of the source of injury or metabolic dysfunction, fibrosis is a frequent driver of liver pathology. Excessive liver fibrosis is caused by persistent activation of hepatic stellate cells (HSCs), which is defined by myofibroblast activation (MFA) and the epithelial-mesenchymal transition (EMT). Strategies to prevent or reverse this HSC phenotype will be critical for successful treatment of liver fibrosis. We have previously shown that full-term, cell-free human amniotic fluid (cfAF) inhibits MFA and EMT in fibroblasts in vitro. We hypothesize that cfAF treatment can attenuate HSC activation and limit liver fibrosis. We tested if cfAF could prevent liver fibrosis or HSC activation in murine models of liver damage, three-dimensional hepatic spheroids, and HSC cultures. Administering cfAF prevented weight loss and the extent of fibrosis in mice with chronic liver damage without stimulating deleterious immune responses. Gene expression profiling and immunostaining indicated that cfAF administration in carbon tetrachloride-treated mice reduced EMT- and MFA-related biomarker abundance and modulated transcript levels associated with liver metabolism, immune regulatory pathways, and cell signaling. cfAF treatment lowered MFA biomarker levels in a dose-dependent manner in ex vivo hepatic spheroids. Treating HSCs with cfAF in vitro strongly repressed EMT. Multi-omics analyses revealed that it also attenuates TGF{beta}-induced MFA and inflammation-associated processes. Thus, cfAF treatment prevents liver fibrosis by safeguarding against persistent HSC activation. These findings suggest that cfAF may be a safe and effective therapy for reducing liver fibrosis and preventing the development of cirrhosis and/or hepatocellular carcinoma. SignificanceChronic activation of hepatic stellate cells leads to irreversible liver fibrosis, and durable treatment options for liver fibrosis remain suboptimal, creating a critical clinical need. Amniotic fluid (AF) reduces inflammation and promotes tissue remodeling and regeneration when applied to cutaneous wounds and in models thereof. However, no prior studies have explored the anti-fibrotic benefits of AF in liver disease. Data from this study indicate that AF can repress liver fibrosis by reducing pro-fibrotic hepatic stellate cell myofibroblast activation. Thus, these findings lay the foundation for early-phase clinical trials investigating cell-free AF as a therapeutic treatment for liver fibrosis and as a bridging therapy for liver transplantation.

cell biology↗

bioRxiv2023

Burkholderia pseudomallei BicA protein promotes pathogenicity in macrophages by regulating Invasion, Intracellular Survival, and Virulence.

Burkholderia pseudomallei (Bpm) is the causative agent of melioidosis disease. Bpm is a facultative intracellular pathogen with a complex lifecycle inside host cells. Pathogenic success depends on a variety of virulence factors with one of the most critical being the type 6 secretion system (T6SS). Bpm uses the T6SS to move into neighboring cells, resulting in multinucleated giant cells (MNGCs) formation, a strategy used to disseminate from cell-to-cell. Our prior study using a dual RNA-seq analysis to dissect T6SS-mediated virulence on intestinal epithelial cells identified BicA as a factor upregulated in a T6SS mutant (1). BicA regulates both type 3 secretion system (T3SS) and T6SSs; however, the extent of its involvement during disease progression is unclear. To fully dissect the role of BicA during systemic infection, we used two macrophage cell lines paired with a pulmonary in vivo challenge murine model. We found that {Delta}bicA has a distinct intracellular replication defect in both immortalized and primary macrophages that begins as early as 1 h post-infection. This intracellular defect is linked with the lack of cell-to-cell dissemination and MNGC formation, as well as a defect on T3SS expression. The in vitro phenotype translated in vivo as {Delta}bicA was attenuated in a pulmonary model of infection; demonstrating a distinct macrophage activation profile and lack of pathological features present in the wild type. Overall, these results highlight the role of BicA in regulating intracellular virulence and demonstrate that specific regulation of secretion systems has a significant effect on host response and Bpm pathogenesis. ImportanceMelioidosis is an understudied tropical disease that still results in [~]50% fatalities from those infected patients. It is caused by the Gram-negative bacillus Burkholderia pseudomallei (Bpm). Bpm is an intracellular pathogen that disseminates from the infected cell to target organs, causing disseminated disease. Regulation of secretion systems involved in entry and cell-to-cell spread is poorly understood. In this work, we characterize the role of BicA as a regulator of secretion systems during infection of macrophages in vitro and in vivo. Understanding how these virulence factors are controlled will help us determine their influence on the host cells and define the macrophage responses associated with bacterial clearance.

microbiology↗

bioRxiv2019

Multispectral Imaging Differentiates Unique Macrophage Profiles in Patients with Distinct Chronic Liver Diseases

Intrahepatic macrophages influence the composition of the microenvironment, host immune response to liver injury, and development of fibrosis. Compared to stellate cells, the role of intrahepatic macrophages in the development of fibrosis remains ill defined. Multispectral imaging allows detection of multiple markers in situ in human formalin-fixed, paraffin-embedded tissue. This cutting-edge technology is ideal for analyzing human liver tissues since it allows spectral unmixing of fluorophore signals, subtraction of auto-fluorescence, and preserves architecture and the in vivo hepatic milieu. We analyzed resident Kupffer cells (CD68+), monocyte-derived macrophages (Mac387+), pro-fibrogenic macrophages (CD163+), and co-expression of pro-inflammatory (CD14) and anti-inflammatory (CD16) markers in liver biopsies from patients with hepatitis C virus (HCV) and different stages of fibrosis. Liver biopsies with advanced fibrosis showed increased accumulation of CD163+, MAC387+ and CD68+ macrophages in the portal tracts when compared to those with minimal fibrosis. Imaging software generated t-distributed stochastic neighbor embedding (t-SNE) plots and phenotype matrices that facilitated comparison of macrophage profiles. These included monocyte-derived (CD68+/Mac387+) and pro-fibrotic/anti-inflammatory (CD163+/CD16+) phenotypes. We established that the utility of this platform could be extended to liver biopsies from patients with other chronic liver diseases including nonalcoholic steatohepatitis and autoimmune hepatitis. Each disease exhibited a unique profile after spectral imaging analysis and this platform holds the potential to identify patients predisposed to progressive liver disease based on the macrophage composition. In summary, spectral imaging is a powerful tool that enables analysis of macrophage profiles in different types of chronic liver diseases and has potential to change the manner in which we evaluate liver biopsies leading to more personalized treatment strategies.

pathology↗