Arthritis & Rheumatology最新文献

Objective: Pigmented villonodular synovitis (PVNS) is a rare benign proliferative disease affecting the soft-tissue lining the synovial joints and tendons. Its etiology is poorly understood, largely limiting the availability of current therapeutic options. Here, we mapped the synovial gene and protein profiles of patients with PVNS, revealed a link between synovial inflammation and invasion, and elucidated the potential molecular mechanism involved.

Methods: The expression of synovial genes from 6 control individuals, 7 patients with osteoarthritis (OA), and 19 patients with PVNS was analyzed via RNA sequencing. Protein profiles from 5 control individuals, 10 patients with OA, and 32 patients with PVNS were analyzed using label-free proteomics. Microarray and reverse transcription-polymerase chain reaction analyses and immunohistochemical staining were used to evaluate inflammatory cytokine and target gene expression levels in synovial tissue, epithelial cells, and synovial fibroblasts (FLSs) derived from tissue of patients with PVNS. Various signaling pathway inhibitors, small interfering RNAs, and Western blots were used for molecular mechanism studies. Transwell migration and invasion assays were subsequently performed.

Results: In total, 522 differentially expressed proteins were identified in the tissues of patients with PVNS. By integrating RNA sequencing and microarray analyses, significant changes in the expression of epithelial-mesenchymal transition (EMT)-related genes, including transforming growth factor TGF-b induced, neural cadherin, epithelial cadherin, SNAIL, and TWIST, were confirmed in the tissue of patients with PVNS compared to the control tissue. In vitro, TGFβ induced EMT and increased epithelial cell migration and invasion. Moreover, TGFβ not only promoted interactions between epithelial cells and FLSs but also directly increased the migration and invasion abilities of FLSs by activating the classical Smad2/3 and nonclassical JNK/AKT signaling pathways.

Conclusion: This study provides overall protein and gene profiles of PVNS and identifies the crucial role of TGFβ in synovial invasion pathology. Exploring the related molecular mechanism may also reveal a new strategy or target for PVNS therapy.

Objective: Autoantibodies are a hallmark of lupus nephritis (LN), but their association with LN classes and treatment response are not adequately known. In this study, we quantified circulating autoantibodies in the Accelerating Medicines Partnership LN longitudinal cohort to identify serological biomarkers of LN histologic classification and treatment response and how these biomarkers change over time based on treatment response.

Methods: Peripheral blood samples were collected from 279 patients with systemic lupus erythematosus undergoing diagnostic kidney biopsy based on proteinuria. Of these, 268 were diagnosed with LN. Thirteen autoantibody specificities were measured by bead-based assays (Bio-Rad Bioplex 2200) and anti-C1q by enzyme-linked immunosorbent assay at the time of biopsy (baseline) and at 3, 6, and 12 months after biopsy. Clinical response was determined at 12 months.

Results: Proliferative LN (International Society of Nephrology/Renal Pathology Society class III/IV±V, n = 160) was associated with higher concentrations of anti-C1q, anti-chromatin, anti-double-stranded DNA (dsDNA), and anti-ribosomal P autoantibodies compared to nonproliferative LN (classes I/II/V/VI, n = 108). Anti-C1q and-dsDNA were independently associated with proliferative LN. In proliferative LN, higher baseline anti-C1q levels predicted complete response (area under the curve [AUC] 0.72; P = 0.002) better than baseline proteinuria (AUC 0.59; P = 0.21). Furthermore, all autoantibody levels except for anti-La/SSB decreased over 12 months in patients with proliferative, but not membranous, LN with a complete response.

Conclusion: Baseline levels of anti-C1q and anti-dsDNA may serve as noninvasive biomarkers of proliferative LN, and anti-C1q may predict complete response at the time of kidney biopsy. In addition, tracking autoantibodies over time may provide further insights into treatment response and pathogenic mechanisms in patients with proliferative LN.

Objective: Rarefaction of blood and lymphatic vessels in the skin has been reported in systemic sclerosis (SSc) (scleroderma). E26 transformation-specific-related factor (ERG) and Friend leukemia virus-induced erythroleukemia 1 (FLI-1) are important regulators of angiogenesis, but their role in lymphatic vasculature is lesser known. The goal of this study was to determine the role of ERG and FLI-1 in postnatal lymphangiogenesis and SSc lymphatic system defects.

Methods: Immunofluorescence was used to detect ERG and FLI-1 in skin biopsy samples from patients with SSc and healthy controls. Transcriptional analysis of ERG or FLI-1-silenced human dermal lymphatic endothelial cells (LECs) was performed using microarrays. Effects of ERG and FLI-1 deficiency on in vitro tubulogenesis in human dermal LECs were examined using a Matrigel assay. ERG and FLI-1 endothelial-specific knockouts and ERG lymphatic-specific knockouts were generated to examine vessel regeneration in mice.

Results: ERG and FLI-1 protein levels were reduced in the blood and lymphatic vasculature in SSc skin biopsy samples. ERG levels were shown to regulate genes involved in lymphatic vessel specification, including vascular endothelial growth factor receptor 3/FLT-4, lymphatic vessel endothelial hyaluronan receptor 1, SOX-18, and prospero homeobox 1 (PROX-1), whereas FLI-1 enhanced the function of ERG. The ERG-FLT-4 pathway regulated in vitro tubulogenesis in human LECs. Deficiency of ERG or FLI-1 similarly impaired the function of blood vessels in mice. However, only ERG deficiency affected the regeneration of lymphatic vessels during wound healing.

Conclusion: ERG and FLI-1 are essential regulators of blood and lymphatic vessel regeneration. Deficiency of ERG and FLI-1 in SSc endothelial cells may contribute to the impairment of blood and lymphatic vasculature in patients with SSc.

Notch ligands and receptors, including JAG1/2, DLL1/4, and Notch1/3, are enriched on macrophages (MΦs), fibroblast-like synoviocytes (FLS), and/or endothelial cells in rheumatoid arthritis (RA) compared with normal synovial tissues (ST). Power Doppler ultrasound-guided ST studies reveal that the Notch family is highly involved in early active RA, especially during neovascularization. In contrast, the Notch family is not implicated during the erosive stage, evidenced by their lack of correlation with radiographic damage in RA ST. Toll-like receptors and tumor necrosis factor (TNF) are the common inducers of Notch expression in RA MΦs, FLS, and endothelial cells. Among Notch ligands, JAG1 and/or DLL4 are most inducible by inflammatory responses in RA MΦs or endothelial cells and transactivate their receptors on RA FLS. TNF plays a central role on Notch ligands, as anti-TNF good responders display JAG1/2 and DLL1/4 transcriptional downregulation in RA ST myeloid cells. In in vitro studies, TNF increases Notch3 expression in MΦs, which is further amplified by RA FLS addition. Specific disease-modifying antirheumatic drugs reduced JAG1 and Notch3 expression in MΦ and RA FLS cocultures. Organoids containing FLS and endothelial cells have increased expression of JAG1 and Notch3. Nonetheless, Methotrexate, interleukin-6 receptor (IL-6R) antibodies, and B cell blockers are mostly ineffective at decreasing Notch family expression. NF-κB, MAPK, and AKT pathways are involved in Notch signaling, whereas JAK/STATs are not. Although Notch blockade has been effective in RA preclinical studies, its small molecule inhibitors have failed in phase I and II studies, suggesting that alternative strategies may be required to intercept their function.

Objective: Autoinflammation and phospholipase C (PLC) γ2-associated antibody deficiency and immune dysregulation (APLAID) syndrome is an autoinflammatory disease caused by gain-of-function variants in PLCG2. This study investigates the pathogenic mechanism of a novel variant of PLCG2 in a patient with APLAID syndrome.

Methods: Whole-exome sequencing and Sanger sequencing were used to identify the pathogenic variant in the patient. Single-cell RNA sequencing, immunoblotting, luciferase assay, inositol monophosphate enzyme-linked immunosorbent assay, calcium flux assay, quantitative PCR, and immunoprecipitation were used to define inflammatory signatures and evaluate the effects of the PLCG2 variant on protein functionality and immune signaling.

Results: We identified a novel de novo variant, PLCG2 p.D993Y, in a patient with colitis, pansinusitis, skin rash, edema, recurrent respiratory infections, B-cell deficiencies, and hypogammaglobulinemia. The single-cell transcriptome revealed exacerbated inflammatory responses in the patient's peripheral blood mononuclear cells. Expression of the D993Y variant in HEK293T, COS-7, and PLCG2 knock-out THP-1 cell lines showed heightened PLCγ2 phosphorylation; elevated inositol-1,4,5-trisphosphate production and intracellular Ca²⁺ release; and activation of the MAPK, NF-κB, and NFAT signaling pathways compared with control-transfected cells. In vitro experiments indicated that the D993Y variant altered amino acid properties, disrupting the interaction between the catalytic and autoinhibitory domains of PLCγ2, resulting in PLCγ2 autoactivation.

Conclusion: Our findings demonstrated that the PLCG2 D993Y variant is a gain-of-function mutation via impairing its autoinhibition, activating multiple inflammatory signaling pathways, thus leading to APLAID syndrome. This study further broadens the molecular underpinnings and phenotypic spectrum of PLCγ2-related disorders.