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High-throughput Quantitative Real-time RT-PCR Assay for Determining Expression Profiles of Types I and III Interferon Subtypes
Published on: March 24, 2015
Type I interferon and Toll-like receptor expression characterizes inflammatory myopathies
C Cappelletti1, F Baggi, F Zolezzi
1Department of Neurology IV, Neurological Institute Foundation Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
Neurology
|June 15, 2011
Summary
Type I interferon (IFN) and endosomal Toll-like receptors (TLRs) are implicated in idiopathic inflammatory myopathies (IIMs), including juvenile dermatomyositis (JDM), dermatomyositis, and polymyositis (PM). These innate immunity pathways suggest potential viral involvement in IIM pathogenesis.
Area of Science:
- Immunology
- Myology
- Genetics
Background:
- Idiopathic inflammatory myopathies (IIMs), including juvenile dermatomyositis (JDM), adult dermatomyositis, and polymyositis (PM), are autoimmune diseases affecting muscles.
- The precise triggers and mechanisms leading to muscle weakness in IIMs are not fully understood.
- Emerging evidence points to a significant role for type I interferon (IFN)-mediated innate immunity in dermatomyositis.
Purpose of the Study:
- To investigate the involvement of type I IFN-dependent genes and Toll-like receptors (TLRs) in the pathogenesis of JDM, dermatomyositis, and PM.
- To explore the differential expression and localization of these immune molecules across different IIM subtypes.
Main Methods:
- Gene expression profiling using microarrays on muscle biopsies from IIM patients and controls.
- Quantitative PCR and immunochemistry to assess type I IFN-dependent genes and TLR expression (TLR3, TLR7, TLR9) in muscle tissues.
Main Results:
- Type I IFN-dependent transcripts were significantly upregulated in IIM muscles compared to controls.
- Specific IFN-stimulated genes (ISG15, IFIT3, MX1, IRF7) were highly expressed in JDM.
- IFN-β transcripts were elevated in PM, dermatomyositis, and JDM, while TLR3, TLR7, and TLR9 showed distinct upregulation patterns in specific IIM subtypes and cell types.
Conclusions:
- Type I IFN-β and its induced molecules play a role in PM, JDM, and dermatomyositis.
- Endosomal TLRs are involved in these conditions, suggesting potential viral triggers, although TLR activation might be secondary to tissue damage.
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