Project description:Vasculitis is characterized by the inflammation of blood vessels. In patients with giant cell arteritis (GCA) large- to medium-sized vessels are affected. Single-cell RNA sequencing was performed on GCA patients and healthy controls (HC) to study the transcriptome of peripheral blood mononuclear cells of patients and controls.
Project description:To identify the key coding genes underlying the biomarkers and pathways associated with giant cell arteritis (GCA), we performed in situ spatial profiling of molecules involved in the temporal arteries of GCA patients and controls
Project description:Background Giant cell arteritis (GCA) is a prevalent, intractable, granulomatous, large-vessel vasculitis. The pathologic features include destruction of the tunica media, infiltrating macrophages and multinucleated giant cells (MNGCs), immune responses associated with CD4+ T cells, accumulation of myofibroblasts, and hypertrophy of the intima. Objectives The molecular pathology of GCA has largely remained elusive, while the morphological features are well defined. We aimed to identify key molecules associated with the pathogenesis of GCA. Method Arterial lesions were obtained through temporal artery biopsy from 16 patients, including those diagnosed as GCA and not. The obtained samples underwent genome-wide gene expression profiling. The resulting data were examined to reveal specific pathways and genes, and some of the molecules were followed up by immunohistochemistry. Results GCA lesions had a distinguishing pattern of gene expression, including enrichment of immune cells and phagocytic pathways related to microglia and osteoclasts. We found MMP12 (macrophage elastase), HLA-DRA, phagocytosis- and osteoclast-associated molecules in infiltrating macrophages and MNGCs. We also found LRRC15-expressing cells in the tunica intima, suggesting a myofibroblast subpopulation that suppresses cytotoxic CD8+ T cells. These molecules were often upregulated in other granulomatous diseases affecting not only arteries but also lymph nodes. Conclusion Infiltrating macrophages and MNGCs expressed molecules that contribute to the pathogenetic features of GCA, including degradation of the tunica medium, induction of immune responses, and accumulation of myofibroblasts. The extended list of key molecules provides a solid baseline of elucidating the pathogenesis of GCA and developing therapeutic strategies.
Project description:Objectives: Giant cell arteritis (GCA) is an autoimmune large-vessels vasculitis with complex etiology. Although the pathogenic mechanisms remain poorly understood, a central role for CD4+ T cells has been demonstrated. In this context, delineating the transcriptome signatures of GCA CD4+ T cells will yield new insights into its pathogenesis. Methods: Transcriptome analysis was conducted on CD4+ T cells from 70 patients with GCA with different disease activity (active patients before treatment and patients in remission with and without glucocorticoid treatment), along with 28 healthy controls. The study also evaluated potential impacts of DNA methylation on gene expression alterations and assessed cross-talk communication with CD14+ monocytes. Results: This study has uncovered a substantial number of genes and pathways potentially contributing to the pathogenicity of CD4+ T cells in GCA. Specifically, CD4+ T cells from GCA patients with active disease exhibited altered expression levels of genes involved in multiple immune-related processes, including various interleukins (IL) signaling pathways. Notably, IL-2, a decisive interleukin for regulatory T cells homeostasis, was among the most significant. Additionally, impaired apoptotic pathways appear to be crucial in GCA development. Our findings also suggest that histone-related epigenetic pathways may be implicated in promoting an inflammatory phenotype in GCA active patients. Finally, our study observed altered signaling communication, such as the Jagged-Notch signaling, between CD4+ T cells and monocytes that could have pathogenic relevance in GCA. Conclusions: Our study suggests the participation of novel cytokines and pathways and the occurrence of a disruption of monocyte-T cell crosstalk driving GCA pathogenesis.
Project description:Objectives: Giant cell arteritis (GCA) is an autoimmune large-vessels vasculitis with complex etiology. Although the pathogenic mechanisms remain poorly understood, a central role for CD4+ T cells has been demonstrated. In this context, delineating the transcriptome signatures of GCA CD4+ T cells will yield new insights into its pathogenesis. Methods: Transcriptome analysis was conducted on CD4+ T cells from 70 patients with GCA with different disease activity (active patients before treatment and patients in remission with and without glucocorticoid treatment), along with 28 healthy controls. The study also evaluated potential impacts of DNA methylation on gene expression alterations and assessed cross-talk communication with CD14+ monocytes. Results: This study has uncovered a substantial number of genes and pathways potentially contributing to the pathogenicity of CD4+ T cells in GCA. Specifically, CD4+ T cells from GCA patients with active disease exhibited altered expression levels of genes involved in multiple immune-related processes, including various interleukins (IL) signaling pathways. Notably, IL-2, a decisive interleukin for regulatory T cells homeostasis, was among the most significant. Additionally, impaired apoptotic pathways appear to be crucial in GCA development. Our findings also suggest that histone-related epigenetic pathways may be implicated in promoting an inflammatory phenotype in GCA active patients. Finally, our study observed altered signaling communication, such as the Jagged-Notch signaling, between CD4+ T cells and monocytes that could have pathogenic relevance in GCA. Conclusions: Our study suggests the participation of novel cytokines and pathways and the occurrence of a disruption of monocyte-T cell crosstalk driving GCA pathogenesis.