Background: Expression of signal transducer and activator of transcription 1 (STAT1), the mediator of interferon (IFN) signalling, is raised in synovial tissue (ST) from patients with rheumatoid ...arthritis (RA). Objectives: To determine the extent to which this pathway is activated by phosphorylation in RA synovium. Additionally, to investigate the cellular basis of STAT1 activation in RA ST. Methods: ST specimens from 12 patients with RA and 14 disease controls (patients with osteoarthritis and reactive arthritis) were analysed by immunohistochemistry, using antibodies to STAT1, tyrosine phosphorylated STAT1, and serine phosphorylated STAT1. Lysates of cultured fibroblast-like synoviocytes stimulated with IFNβ were analysed by western blotting. Phenotypic characterisation of cells expressing STAT1 in RA ST was performed by double immunolabelling for STAT1 and CD3, CD22, CD55, or CD68. Results: Raised levels of total STAT1 protein and both its activated tyrosine and serine phosphorylated forms were seen in RA synovium as compared with controls. STAT1 was predominantly abundant in T and B lymphocytes in focal inflammatory infiltrates and in fibroblast-like synoviocytes in the intimal lining layer. Raised levels of STAT1 are sustained in cultured RA compared with OA fibroblast-like synoviocytes, and STAT1 serine and tyrosine phosphorylation is rapidly induced upon stimulation with IFNβ. Conclusion: These results demonstrate activation of the STAT1 pathway in RA synovium by raised STAT1 protein expression and concomitantly increased tyrosine (701) and serine (727) phosphorylation. High expression of STAT1 is intrinsic to RA fibroblast-like synoviocytes in the intimal lining layer, whereas activation of the pathway by phosphorylation is an active process.
Genomics in the immune system van der Pouw Kraan, Tineke C.M.T; Kasperkovitz, Pia V; Verbeet, Nicolette ...
Clinical immunology (Orlando, Fla.),
05/2004, Letnik:
111, Številka:
2
Journal Article
Recenzirano
The analysis of gene expression in tissues, cells, and biologic systems has evolved in the last decade from the analysis of a selected set of genes to an efficient high throughput whole-genome ...screening approach of potentially all genes expressed in a tissue or cell sample. Development of sophisticated methodologies such as microarray technology allows an open-ended survey to identify comprehensively the fraction of genes that are differentially expressed between samples and define the samples' unique biology. This discovery-based research provides the opportunity to characterize either new genes with unknown function or genes not previously known to be involved in a biologic process. The latter category may hold surprises that sometimes urge us to redirect our thinking. Here, we review the impact of large-scale gene expression profiling by DNA-microarray technology on basic and clinical aspects of immunology.
CD82 controls CpG‐dependent TLR9 signaling Khan, Nida S.; Lukason, Daniel P.; Feliu, Marianela ...
The FASEB journal,
November 2019, 2019-11-00, 20191101, Letnik:
33, Številka:
11
Journal Article
Recenzirano
Odprti dostop
The tetraspanin CD82 is a potent suppressor of tumor metastasis and regulates several processes including signal transduction, cell adhesion, motility, and aggregation. However, the mechanisms by ...which CD82 participates in innate immunity are unknown. We report that CD82 is a key regulator of TLR9 trafficking and signaling. TLR9 recognizes unmethylated cytosine‐phosphate‐guanine (CpG) motifs present in viral, bacterial, and fungal DNA. We demonstrate that TLR9 and CD82 associate in macrophages, which occurs in the endoplasmic reticulum (ER) and post‐ER. Moreover, CD82 is essential for TLR9‐dependent myddosome formation in response to CpG stimulation. Finally, CD82 modulates TLR9‐dependent NF‐αB nuclear translocation, which is critical for inflammatory cytokine production. To our knowledge, this is the first time a tetraspanin has been implicated as a key regulator of TLR signaling. Collectively, our study demonstrates that CD82 is a specific regulator of TLR9 signaling, which may be critical in cancer immunotherapy approaches and coordinating the innate immune response to pathogens.—Khan, N. S., Lukason, D. P., Feliu, M., Ward, R. A., Lord, A. K., Reedy, J. L., Ramirez‐Ortiz, Z. G., Tam, J. M., Kasperkovitz, P. V., Negoro, P. E., Vyas, T. D., Xu, S., Brinkmann, M. M., Acharaya, M., Artavanis‐Tsakonas, K., Frickel, E.‐M., Becker, C. E., Dagher, Z., Kim, Y.‐M., Latz, E., Ploegh, H. L., Mansour, M. K., Miranti, C. K., Levitz, S. M., Vyas, J. M. CD82 controls CpG‐dependent TLR9 signaling. FASEB J. 33, 12500–12514 (2019). www.fasebj.org
Objective
To generate a molecular description of synovial tissue from rheumatoid arthritis (RA) patients that would allow us to unravel novel aspects of pathogenesis and to identify different forms ...of disease.
Methods
We applied complementary DNA microarray analysis to profile gene expression, with a focus on immune‐related genes, in affected joint tissues from RA patients and in tissues from osteoarthritis (OA) patients as a control. To validate microarray data, real‐time polymerase chain reaction was performed on genes of interest.
Results
The gene expression signatures of synovial tissues from RA patients showed considerable variability, resulting in the identification of at least two molecularly distinct forms of RA tissues. One class of tissues revealed abundant expression of clusters of genes indicative of an involvement of the adaptive immune response. Detailed analysis of the expression profile provided evidence for a prominent role of an activated signal transducer and activator of transcription 1 pathway in these tissues. The expression profiles of another group of RA tissues revealed an increased tissue remodeling activity and a low inflammatory gene expression signature. The gene expression pattern in the latter tissues was reminiscent of that observed in the majority of OA tissues.
Conclusion
The differences in the gene expression profiles provide a unique perspective for distinguishing different pathogenetic RA subsets based on molecular criteria. These data reflect important aspects of molecular variation that are relevant for understanding the biologic dysregulation underlying these subsets of RA. This approach may also help to define homogeneous groups for clinical studies and evaluation of targeted therapies.
Objective
Given the heterogeneity of gene expression patterns and cellular distribution between rheumatoid arthritis (RA) synovial tissues, we sought to determine whether this variability was also ...reflected at the level of the fibroblast‐like synoviocyte (FLS) cultured from RA synovial tissues.
Methods
Gene expression profiles in FLS cultured from synovial tissues obtained from 19 RA patients were analyzed using complementary DNA microarrays and hierarchical cluster analysis. To validate the subclassification, we performed prediction analysis and principal components analysis. Genes that differed significantly in their expression between FLS cultures were selected using Statistical Analysis of Microarrays software. Real‐time quantitative polymerase chain reaction was performed to validate the microarray data. Immunocytochemistry was applied to study the expression of the genes of interest in FLS and synovial tissues.
Results
Hierarchical clustering identified 2 main groups of FLS characterized by distinctive gene expression profiles. FLS from high‐inflammation synovial tissues revealed increased expression of a transforming growth factor β/activin A–inducible gene profile that is characteristic of myofibroblasts, a cell type considered to be involved in wound healing, whereas increased production of growth factor (insulin‐like growth factor 2/insulin‐like growth factor binding protein 5) appeared to constitute a characteristic feature of FLS derived from low‐inflammation synovial tissues. The molecular feature that defines the myofibroblast‐like phenotype was reflected as an increased proportion of myofibroblast‐like cells in the heterogeneous FLS population. Myofibroblast‐like cells were also found upon immunohistochemical analysis of synovial tissue.
Conclusion
Our findings support the notion that heterogeneity between synovial tissues is reflected in FLS as a stable trait, and provide evidence of a possible link between the behavior of FLS and the inflammation status of RA synovium.
PDF
