Selected Grantee Publications
Matrikine Stimulation of Equine Synovial Fibroblasts and Chondrocytes Results in an In Vitro Osteoarthritis Phenotype
Gagliardi et al., Journal of Orthopaedic Research. 2025.
https://pubmed.ncbi.nlm.nih.gov/39486895
Advancements in therapy development for osteoarthritis (OA) currently are limited due to a lack of physiologically relevant in vitro models. This study aimed to understand the effect of matrikine stimulation, using human recombinant fibronectin fragment containing domains 7–10 (FN7–10), on equine synovial fibroblasts and chondrocytes. Inflammatory cytokines, chemokines, and matrix degradation genes in equine synovial fibroblasts and chondrocytes were significantly altered in response to FN7–10 stimulation; marked upregulation was observed in interleukin-6 (IL-6), IL-4, IL-10, matrix metalloproteinase 1 (MMP1), MMP3, MMP13, CCL2/MCP1, and CXCL6/GCP-2 gene expression. Only IL-6 protein production was significantly increased in media isolated from cells stimulated with FN7–10. These results support the potential use of equine synovial fibroblasts and chondrocytes—employing FN7–10—as representative in vitro models to study OA. Supported by ORIP (T32OD011130) and NIAMS.
Transcriptomic Analysis of Skeletal Muscle Regeneration Across Mouse Lifespan Identifies Altered Stem Cell States
Walter et al., Nature Aging. 2024.
https://pubmed.ncbi.nlm.nih.gov/39578558
Age-related skeletal muscle regeneration dysfunction is poorly understood. Using single-cell transcriptomics and high-resolution spatial transcriptomics, researchers evaluated factors contributing to age-related decline in skeletal muscle regeneration after injury in young, old, and geriatric male and female mice (5, 20, and 26 months old). Eight immune cell types were identified and associated with age-related dynamics and distinct muscle stem cell states specific to old and geriatric tissue. The findings emphasize the role of extrinsic and intrinsic factors, including cellular senescence, in disrupting muscle repair. This study provides a spatial and molecular framework for understanding regenerative decline and cellular heterogeneity in aging skeletal muscle. Supported by ORIP (F30OD032097), NIA, NIAID, NIAMS, NICHD, and NIDA.
Deletion of Mouse Lysyl Oxidase in Megakaryocytes Affects Bone Properties in a Sex-Dependent Manner
Karagianni, Cell. 2024.
https://pubmed.ncbi.nlm.nih.gov/38635757/
Lysyl oxidase (LOX) is a facilitator of extracellular matrix cross-linking, and the importance of LOX in bone formation has been addressed in both in vitro and in vivo studies. Using newly developed megakaryocyte-specific LOX knockout mice, the researchers show that LOX expressed in these scarce bone marrow cells leads to changes in bone volume and mechanical strength in male mice; however, no significant changes were observed within the female experimental groups. The authors’ findings suggest that sex hormones could contribute to differences within these dynamics. Supported by ORIP (K01OD025290) and NIAMS.
Loss of Lymphatic IKKα Disrupts Lung Immune Homeostasis, Drives BALT Formation, and Protects Against Influenza
Cully et al., Immunohorizons. 2024.
https://pubmed.ncbi.nlm.nih.gov/39007717/
Tertiary lymphoid structures (TLS) have context-specific roles, and more work is needed to understand how they function in separate diseases to drive or reduce pathology. Researchers showed previously that lymph node formation is ablated in mice constitutively lacking IκB kinase alpha (IKKα) in lymphatic endothelial cells (LECs). In this study, they demonstrated that loss of IKKα in lymphatic endothelial cells leads to the formation of bronchus-associated lymphoid tissue in the lung. Additionally, they showed that male and female mice challenged with influenza A virus (IAV) exhibited markedly improved survival rates and reduced weight loss, compared with littermate controls. They concluded that ablating IKKα in this tissue reduces the susceptibility of the mice to IAV infection through a decrease in proinflammatory stimuli. This work provides a new model to explore the mechanisms of TLS formation and the immunoregulatory function of lung lymphatics. Supported by ORIP (T35OD010919), NHLBI, NIAID, and NIAMS.
The Monarch Initiative in 2024: An Analytic Platform Integrating Phenotypes, Genes and Diseases Across Species
Putman et al., Nucleic Acids Research. 2024.
https://pubmed.ncbi.nlm.nih.gov/38000386/
The Monarch Initiative aims to bridge the gap between the genetic variations, environmental determinants, and phenotypic outcomes critical for translational research. The Monarch app provides researchers access to curated data sets with information on genes, phenotypes, and diseases across species and advanced analysis tools for such diverse applications as variant prioritization, deep phenotyping, and patient profile matching. Researchers describe upgrades to the app, including scalable cloud-based infrastructure, simplified data ingestion and knowledge graph integration systems, enhanced data mapping and integration standards, and a new user interface with novel search and graph navigation features. A customized plugin for OpenAI’s ChatGPT allows the use of large language models to interrogate knowledge in the Monarch graph and increase the reliability of the responses of Monarch’s analytic tools. These upgrades will enhance clinical diagnosis and the understanding of disease mechanisms. Supported by ORIP (R24OD011883), NLM, and NHGRI.
Lipid Droplets and Peroxisomes Are Co-Regulated to Drive Lifespan Extension in Response to Mono-Unsaturated Fatty Acids
Papsdorf et al., Nature Cell Biology. 2023.
https://www.nature.com/articles/s41556-023-01136-6
Investigators studied the mechanism by which mono-unsaturated fatty acids (MUFAs) extend longevity. They found that MUFAs upregulated the number of lipid droplets in fat storage tissues of Caenorhabditis elegans, and increased lipid droplets are necessary for MUFA-induced longevity and predicted remaining lifespan. Lipidomics data revealed that MUFAs modify the ratio of membrane lipids and ether lipids, which leads to decreased lipid oxidation in middle-aged individuals. MUFAs also upregulate peroxisome number. A targeted screen revealed that induction of both lipid droplets and peroxisomes is optimal for longevity. This study opens new interventive avenues to delay aging. Supported by ORIP (S10OD025004, S10OD028536, P40OD010440), NIA, NCCIH, NIDDK, and NHGRI.
The Eotaxin-1/CCR3 Axis and Matrix Metalloproteinase-9 Are Critical in Anti-NC16A IgE-Induced Bullous Pemphigoid
Jordan et al., Journal of Immunology. 2023.
Bullous pemphigoid is associated with eosinophilic inflammation and circulating and tissue-bound IgG and IgE autoantibodies. Researchers previously established the pathogenicity of anti-NC16A IgE through passive transfer of patient-derived autoantibodies to double-humanized mice. In this study, they characterized the molecular and cellular events that underlie eosinophil recruitment and eosinophil-dependent tissue injury. Their work establishes the eotaxin-1/CCR3 axis and matrix metalloproteinase-9 as key players in the disease and as candidate therapeutic targets for drug development and testing. Supported by ORIP (T32OD011130) and NIAMS.
A Gut-Restricted Glutamate Carboxypeptidase II Inhibitor Reduces Monocytic Inflammation and Improves Preclinical Colitis
Peters et al., Science Translational Medicine. 2023.
https://www.science.org/doi/10.1126/scitranslmed.abn7491
Many patients with moderate-to-severe inflammatory bowel disease (IBD) do not have adequate disease control, and glutamate carboxypeptidase II (GCPII) offers a promising target for therapeutic development. Researchers generated a class of GCPII inhibitors. They demonstrated that the inhibitor reduced monocytic inflammation in mice and protected against the loss of barrier integrity in primary human colon epithelial air–liquid interface monolayers. Their findings suggest that local inhibition of GCPII could be applied for the development of IBD therapeutics. Supported by ORIP (K01OD030517, T32OD011089), NIGMS, and NCCIH.
Effects of Acute Femoral Head Ischemia on the Growth Plate and Metaphysis in a Piglet Model of Legg-Calvé-Perthes Disease
Armstrong et al., Osteoarthritis and Cartilage. 2023.
https://pubmed.ncbi.nlm.nih.gov/36696941/
Legg-Calvé-Perthes disease (LCPD) can lead to permanent deformity of the femoral head and premature osteoarthritis, but the underlying cause remains unknown. More work is needed to determine optimal treatment methods for LCPD. Using a piglet model for LCPD, researchers assessed the effects of acute femoral head ischemia on the proximal femoral growth plate and metaphysis. They reported that alterations to the growth plate zones and metaphysis occurred by 2 days post-ischemia and persisted at 7 days post-ischemia. These findings suggest that growth disruption may occur sooner after the onset of ischemia than researchers had hypothesized previously. Supported by ORIP (T32OD010993, K01OD021293), NIAMS, and NCATS.
Naturally Occurring Osteochondrosis Latens Lesions Identified by Quantitative and Morphological 10.5 T MRI in Pigs
Armstrong et al., Journal of Orthopaedic Research. 2023.
https://pubmed.ncbi.nlm.nih.gov/35716161/
Juvenile osteochondritis dissecans (JOCD) is a pediatric orthopedic disorder that is associated with pain and gait deficits. JOCD lesions form in the knee, elbow, and ankle joints and can progress to early-onset osteoarthritis. In this study, researchers used a noninvasive magnetic resonance imaging (MRI) method to identify naturally occurring lesions in intact knee and elbow joints of juvenile pigs. This work can be applied to noninvasive identification and monitoring of early JOCD lesions and determination of risk factors that contribute to their progression in children. Supported by ORIP (K01OD021293, T32OD010993), NIAMS, and NIBIB.