Protein and Transcriptomic Differences Between High and Low Neointimal Arteries in Human Cardiac Allograft Vasculopathy Rejected Grafts
J. Nevarez-Mejia1, H. C. Pickering1, R. A. Sosa1, R. P. Lau1, G. A. Fishbein1, W. M. Baldwin III2, R. L. Fairchild2, E. F. Reed1
1University of California, Los Angeles, Los Angeles, CA, 2Cleveland Clinic Main Campus, Lerner Research Institute, Cleveland, OH
Meeting: 2022 American Transplant Congress
Abstract number: 1317
Keywords: Alloantibodies, Autoimmunity, Gene expression, Graft failure
Topic: Basic Science » Basic Clinical Science » 19 - Chronic Organ Rejection
Session Information
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: Cardiac allograft vasculopathy (CAV) is the leading cause of graft failure and mortality following heart transplantation. Donor specific antibodies (DSA) contribute to CAV progression by activating alloimmune responses against the graft vasculature. Continued episodes of endothelial cell injury and chronic inflammation results in thickening of the arterial intima followed by vessel occlusion. The purpose of this study is to molecularly characterize the innate and adaptive immune cells mediating inflammation and vessel neointima formation using explanted cardiac transplants and GeoMx digital spatial profiling (DSP).
*Methods: Cardiac allograft explants from CAV+DSA+ patients (N=3; 2 females, 1 male) were subjected to DSP analysis. Immunofluorescent staining for macrophages (CD68+CD163+) within vessels (CD34+) as well as H&E was used to select arteries of interest. Arteries were scored based on the level of CAV progression/neointimal thickening. In total, 11 arteries were scored with ‘low’ neointima (+/- minimal and 1+ mild) and 11 with ‘high’ neointima (2+ moderate, 3+ significant, and 4+ very significant). All arteries were subjected to whole genome sequencing and a 76-protein panel for immune-related markers. Weighted gene-correlation network analysis (WGCNA) was used to identify co-expressed genes and enriched pathways.
*Results: A total of 41 proteins were found to be expressed in all arteries. These included markers for immune-infiltrates, inflammation, and apoptosis. Precisely, the expression of CD8, CD56, CD20, CD127, and CD11c exhibited a significantly positive correlation (p<0.05) with RNA counterpart levels. A total of 15 differentially expressed proteins were elevated in arteries with low neointima. These included markers related to T-cells (CD8, CD45RO, CD127, and TIM-3), monocytes (CD14), and apoptosis (p53). Moreover, arteries with low neointima exhibited high expression of genes related to inflammatory responses (ITGAX) and apoptosis (TP63), along with pathway enrichment of antigen presentation, and caspase activation. Arteries with high neointima exhibited higher expression of SMA protein and increased genes related to cell-cycle activation (CDC7), cell growth (LECT2), complement regulation (CFHR3) and anti-inflammatory factors (FNDC4). Enriched pathways in high neointimal arteries included platelet activation/degranulation and semaphorin 4D induced cell migration.
*Conclusions: Our results provide insight into the mechanisms mediating CAV progression observed by inflammatory profiles in arteries with low neointima followed by pro-fibrotic and reparative phenotypes in high neointima arteries. These findings form the foundation for the discovery of improved biomarkers for CAV diagnosis and treatment.
To cite this abstract in AMA style:
Nevarez-Mejia J, Pickering HC, Sosa RA, Lau RP, Fishbein GA, III WMBaldwin, Fairchild RL, Reed EF. Protein and Transcriptomic Differences Between High and Low Neointimal Arteries in Human Cardiac Allograft Vasculopathy Rejected Grafts [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/protein-and-transcriptomic-differences-between-high-and-low-neointimal-arteries-in-human-cardiac-allograft-vasculopathy-rejected-grafts/. Accessed October 3, 2024.« Back to 2022 American Transplant Congress