Elsevier

Neuromuscular Disorders

Volume 9, Issue 4, 1 June 1999, Pages 239-246
Neuromuscular Disorders

Immunolocalization of tumor necrosis factor-alpha and its receptors in inflammatory myopathies1

https://doi.org/10.1016/S0960-8966(98)00126-6Get rights and content

Abstract

Adhesion molecule upregulation occurs in inflammatory myopathies, and is one of the myriad functions of tumor necrosis factor-α (TNF-α). TNF-α acts via two different receptors of 55 (TNF-R55) and 75 kD (TNF-R75). We immunolocalized TNF-α and its receptors in polymyositis, inclusion body myositis and dermatomyositis. In each myopathy, TNF-α was detected in macrophages, in myonuclei in regenerating muscle fibers, and freely dispersed in endomysial or perimysial connective tissue. Many endothelial cells in dermatomyositis expressed TNF-α. TNF-R55 was strongly expressed on myonuclei of regenerating muscle fibers. TNF-R75 was increased on endothelial cells in the midst of inflammatory infiltrates in each myopathy, and on perifascicular and perimysial endothelia, remote from inflammatory foci in dermatomyositis. Possible TNF-α-mediated effects include: increased transendothelial cell trafficking, activation of T/B cells and macrophages, induction of MHC-I gene products, and focal muscle fiber atrophy. In dermatomyositis, the upregulated TNF-R75, via its consensus elements for transcription factors, may be involved in endothelial cell degeneration. Strong TNF-R55 expression on regenerating myonuclei is consistent with a role of TNF-α and TNF-R55 in muscle regeneration.

Introduction

Upregulation or induction of certain cell adhesion molecules has been implicated in the immunopathogenesis of inflammatory myopathies 1, 2, 3. In polymyositis (PM) and sporadic inclusion body myositis (IBM), cytotoxic CD8 T cells focally surround and invade non-necrotic muscle fibers 4, 5, 6, 7. The muscle fiber surfaces, facing the autoaggressive infiltrate, express intercellular adhesion molecule-1 (ICAM-1) that serves as a ligand for lymphocyte function associated antigen-1 (LFA-1) expressed on the invading T cells [1]. In dermatomyositis (DM), the main immune effector mechanism is humoral and directed against endothelial cells of the intramuscular microvasculature [8]. ICAM-1, but no other endothelial cell-associated adhesion molecules, is selectively upregulated on endothelial cells in affected parts of the muscle biopsies, suggesting that this ligand is differentially upregulated in this disease [1]. In all inflammatory myopathies, CD45RO+ memory cells represent the main T cell subset [9]. CD45RO+ cells adhere to and extravasate from blood vessels more readily than their CD45RA+ naive counterparts [10].

The cytokines interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) strongly upregulate ICAM-1 on cultured human myoblasts [11]. Previous studies failed to document an important role for IFN-γ in inflammatory myopathies [12]or yielded equivocal results [13]. In a recent study, signal transducer and activator of transcription 1 (STAT1) was increased in perifascicular muscle fibers in DM, indirectly indicating a possible role for IFN-γ in this myopathy [14]. The role of TNF-α in inflammatory myopathies is unknown.

TNF-α is a pleiotropic cytokine involved in diverse biologic functions including immune and inflammatory reactions. Besides induction of cell adhesion molecules, this monokine activates T and B cells and macrophages, triggers endothelia to secrete a number of cytokines, increases major histocompatibility class-I (MHC-I) expression on target structures of CD8 cytotoxic T cells, and induces apoptotic cell death in cultured cells 15, 16, 17. TNF-α exerts these effects via two receptors of 55 (TNF-R55) and 75 kD (TNF-R75), respectively. Based on their amino acid sequence, the two receptors are only 29% identical to each other, and there is ample evidence that they are differentially regulated [18]. Most TNF-α functions, including induction of adhesion molecule expression, antiviral activity, and cytotoxicity are predominantly mediated through TNF-R55, but others require the expression of both receptors on the target structure 19, 20, 21, 22, 23, 24, 25, 26. TNF-R75 then functions as a `ligand passer' concentrating TNF-α at the cell surface and transferring the ligand to TNF-R55 that mediates signaling [27]. Recently, it has been shown that TNF-R75, by itself, is able to mediate thymocyte proliferation and cytotoxic signaling in specific cell lines 20, 28.

The present study investigates the expression of TNF-α and its receptors on muscle fibers, endothelial cells and inflammatory cells in muscle from PM, IBM and DM patients and in normal controls.

Section snippets

Patients

Limb muscle biopsies from patients with IBM (six), PM (six), or DM (six) were studied. The diagnoses were based on conventional criteria. None of the patients had received immunosuppressive drugs within 3 months preceding the biopsy. All patients had had progressive disease in the weeks or months preceding the biopsy. Muscle specimens from six subjects who were ultimately deemed free of neuromuscular disease by clinical, electromyographic and histologic criteria served as controls.

Immunoreagents and immunocytochemical procedures

Consecutive 4-

Results

Table 2 summarizes TNF-α protein and TNF-R55 and TNF-R75 receptor immunolocalization at different sites in control specimens and in each disease. The findings in IBM and PM were similar and they are therefore described together.

Discussion

We demonstrate immunoreactivity for TNF-α and describe in detail the expression of the two known TNF receptors in each main type of inflammatory myopathy. Our observations strongly suggest the involvement of TNF-α in the pathogenesis of these myopathies. TNF-α was mainly detected in endothelial cells and macrophages and freely dispersed in endomysial or perimysial connective tissue. The strong TNF-R55 expression on myonuclei of regenerating muscle fibers suggests implication of TNF-α and

Acknowledgements

This study was supported by grants from the Flemish Fund for Scientific Research and the Gent University Research Fund. The authors thank W. Fiers and A.G. Engel, for their support and advice. S. Pappens and W. Drijvers provided expert technical assistance.

References (48)

  • M.P Boldin et al.

    Self-association of the `death domains' of the p55 tumor necrosis factor (TNF) receptor and Fas/APO1 prompts signaling for TNF and Fas/APO1 effects

    J Biol Chem

    (1995)
  • J.L De Bleecker et al.

    Expression of cell adhesion molecules in inflammatory myopathies and Duchenne dystrophy

    J Neuropathol Exp Neurol

    (1994)
  • K Arahata et al.

    Monoclonal antibody analysis of mononuclear cells in myopathies. I. Quantitation of subsets according to diagnosis and sites of accumulation and demonstration and counts of muscle fibers invaded by T cells

    Ann Neurol

    (1984)
  • K Arahata et al.

    Monoclonal antibody analysis of mononuclear cells in myopathies. V. Identification and quantitation of T8+ cytotoxic and T8+ suppressor cells

    Ann Neurol

    (1988)
  • M.C Dalakas

    Polymyositis, dermatomyositis, and inclusion body myositis

    N Engl J Med

    (1991)
  • R.C Griggs et al.

    Inclusion body myositis and myopathies

    Ann Neurol

    (1995)
  • A.M Emslie-Smith et al.

    Microvascular changes in early and advanced dermatomyositis: a quantitative study

    Ann Neurol

    (1990)
  • J.L De Bleecker et al.

    Immunocytochemical study of CD45 T cell isoforms in inflammatory myopathies

    Am J Pathol

    (1995)
  • A.H Lichtman et al.

    CD45RA-RO+ (memory) but not CD45RA+RO−(naive) T cells roll efficiently on E- and P-selectin and vascular cell adhesion molecule-1 under flow

    J Immunol

    (1997)
  • D Michaelis et al.

    Constitutive and cytokine-induced expression of human leukocyte antigens and cell adhesion molecules by human myotubes

    Am J Pathol

    (1993)
  • D.A Isenberg et al.

    Localization of interferon and interleukin-2 in polymyositis and muscular dystrophy

    Clin Exp Immunol

    (1986)
  • I Illa et al.

    Signal transducer and activator of transcription 1 in human muscle. Implications in inflammatory myopathies

    Am J Pathol

    (1997)
  • P Vandenabeele et al.

    Functional characterization of the human tumor necrosis factor receptor p75 in a transfected rat/mouse T cell hybridoma

    J Exp Med

    (1992)
  • M Brockhaus et al.

    Identification of two types of tumor necrosis factor receptors on human cell lines by monoclonal antibodies

    Proc Natl Acad Sci USA

    (1990)
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