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Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension.

ABSTRACT: Idiopathic pulmonary arterial hypertension (IPAH) is a devastating pulmonary vascular disease in which autoimmune and inflammatory phenomena are implicated. B cells and autoantibodies have been associated with IPAH and identified as potential therapeutic targets. However, the specific populations of B cells involved and their roles in disease pathogenesis are not clearly defined. We aimed to assess the levels of activated B cells (plasmablasts) in IPAH, and to characterize recombinant antibodies derived from these plasmablasts. Blood plasmablasts are elevated in IPAH, remain elevated over time, and produce IgA autoantibodies. Single-cell sequencing of plasmablasts in IPAH revealed repertoires of affinity-matured antibodies with small clonal expansions, consistent with an ongoing autoimmune response. Recombinant antibodies representative of these clonal lineages bound known autoantigen targets and displayed an unexpectedly high degree of polyreactivity. Representative IPAH plasmablast recombinant antibodies stimulated human umbilical vein endothelial cells to produce cytokines and overexpress the adhesion molecule ICAM-1. Together, our results demonstrate an ongoing adaptive autoimmune response involving IgA plasmablasts that produce anti-endothelial cell autoantibodies in IPAH. These antibodies stimulate endothelial cell production of cytokines and adhesion molecules, which may contribute to disease pathogenesis. These findings suggest a role for mucosally-driven autoimmunity and autoimmune injury in the pathogenesis of IPAH.

SUBMITTER: Blum LK

PROVIDER: S-EPMC5992033 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension.

Blum Lisa K LK Cao Richard R L RRL Sweatt Andrew J AJ Bill Matthew M Lahey Lauren J LJ Hsi Andrew C AC Lee Casey S CS Kongpachith Sarah S Ju Chia-Hsin CH Mao Rong R Wong Heidi H HH Nicolls Mark R MR Zamanian Roham T RT Robinson William H WH

European journal of immunology 20180222 5

Idiopathic pulmonary arterial hypertension (IPAH) is a devastating pulmonary vascular disease in which autoimmune and inflammatory phenomena are implicated. B cells and autoantibodies have been associated with IPAH and identified as potential therapeutic targets. However, the specific populations of B cells involved and their roles in disease pathogenesis are not clearly defined. We aimed to assess the levels of activated B cells (plasmablasts) in IPAH, and to characterize recombinant antibodies ...[more]

PMID: 29369345

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Project description:Pulmonary vascular arterial remodeling is an integral and well-understood component of pulmonary hypertension (PH). In contrast, morphological alterations of pulmonary veins in PH are scarcely described. Explanted lungs (n = 101) from transplant recipients with advanced chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary arterial hypertension (IPAH) were analyzed for venous vascular involvement according to a pre-specified, semi-quantitative grading scheme, which categorizes the intensity of venous remodeling in three groups of incremental severity: venous hypertensive (VH) grade 0 = characterized by an absence of venous vascular remodeling; VH grade 1 = defined by a dominance of either arterialization or intimal fibrosis; and VH grade 2 = a substantial composite of arterialization and intimal fibrosis. Patients were grouped according to clinical and hemodynamic characteristics in three groups: COPD non-PH, COPD-PH, and IPAH, respectively. Histological specimens were examined by a cardiovascular pathologist blinded to clinical and hemodynamic data. Pathological alterations of pulmonary veins were present in all hemodynamic groups, with the following incidences of VH grade 0/1/2: 34/66/0% in COPD non-PH; 19/71/10% in COPD-PH; and 11/61/28% in IPAH. In COPD, explorative correlation analysis of venous remodeling suggested a modest positive correlation with systolic and mean pulmonary artery pressure ( P = 0.032, respectively) and an inverse modest correlation with diffusion capacity for carbon monoxide ( P = 0.027). In addition, venous remodeling correlated positively with the degree of arterial remodeling ( P = 0.014). In COPD-PH and IPAH, advanced forms of pulmonary venous remodeling are present, emphasizing that the disease is not exclusively restricted to arterial lesions. In addition, venous remodeling may be related to the hemodynamic severity, but more rigorous analysis is required to clearly define potential relationships.

Project description:Despite recent improvements in management of idiopathic pulmonary arterial hypertension, mortality remains high. Understanding the alterations in the transcriptome–phenotype of the key lung cells involved could provide insight into the drivers of pathogenesis. In this study, we examined differential gene expression of cell types implicated in idiopathic pulmonary arterial hypertension from lung explants of patients with idiopathic pulmonary arterial hypertension compared to control lungs. After tissue digestion, we analyzed all cells from three idiopathic pulmonary arterial hypertension and six control lungs using droplet-based single cell RNA-sequencing. After dimensional reduction by t-stochastic neighbor embedding, we compared the transcriptomes of endothelial cells, pericyte/smooth muscle cells, fibroblasts, and macrophage clusters, examining differential gene expression and pathways implicated by analysis of Gene Ontology Enrichment. We found that endothelial cells and pericyte/smooth muscle cells had the most differentially expressed gene profile compared to other cell types. Top differentially upregulated genes in endothelial cells included novel genes: ROBO4, APCDD1, NDST1, MMRN2, NOTCH4, and DOCK6, as well as previously reported genes: ENG, ORAI2, TFDP1, KDR, AMOTL2, PDGFB, FGFR1, EDN1, and NOTCH1. Several transcription factors were also found to be upregulated in idiopathic pulmonary arterial hypertension endothelial cells including SOX18, STRA13, LYL1, and ELK, which have known roles in regulating endothelial cell phenotype. In particular, SOX18 was implicated through bioinformatics analyses in regulating the idiopathic pulmonary arterial hypertension endothelial cell transcriptome. Furthermore, idiopathic pulmonary arterial hypertension endothelial cells upregulated expression of FAM60A and HDAC7, potentially affecting epigenetic changes in idiopathic pulmonary arterial hypertension endothelial cells. Pericyte/smooth muscle cells expressed genes implicated in regulation of cellular apoptosis and extracellular matrix organization, and several ligands for genes showing increased expression in endothelial cells. In conclusion, our study represents the first detailed look at the transcriptomic landscape across idiopathic pulmonary arterial hypertension lung cells and provides robust insight into alterations that occur in vivo in idiopathic pulmonary arterial hypertension lungs.

Dataset Information

Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension.

Publications

Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension.

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