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Expression of 65-kd heat shock proteins in the inflammatory myopathies
1Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905.
Abstract:
In normal muscle, 65-kd heat shock proteins (hsp) were detected on capillary endothelial cells, the mural elements of larger vessels, and some intracellular organelles, probably mitochondria. In the inflammatory myopathies, the 65-kd hsp were detected on inflammatory cells, degenerating and regenerating fibers, and on many but not all nonnecrotic muscle fibers invaded by T cells. The expression of the 65-kd hsp may be an immune-nonspecific response to cellular "stress," but hsp determinants could possibly also serve as autoantigen(s) recognized by autoreactive T cells.
Insights
In inflammatory myopathies, 65-kd heat shock proteins (hsp) appear on stressed muscle cells and inflammatory cells. These hsp may be a response to cellular stress or recognized by the immune system as autoantigens.
Area of Science:
- Immunology
- Cell Biology
- Neurology
Background:
- Heat shock proteins (hsp) are involved in cellular stress responses.
- Their role in inflammatory myopathies is not fully understood.
- Previous studies have indicated hsp expression in various cellular components.
Purpose of the Study:
- To investigate the expression and localization of 65-kd heat shock proteins (hsp) in normal and inflammatory myopathic muscle.
- To explore the potential role of 65-kd hsp in the pathogenesis of inflammatory myopathies.
Main Methods:
- Immunohistochemical detection of 65-kd hsp in muscle biopsies.
- Analysis of hsp localization in relation to cellular structures and inflammatory infiltrates.
Main Results:
- In normal muscle, 65-kd hsp were found on capillary endothelial cells, larger vessel walls, and intracellular organelles (likely mitochondria).
- In inflammatory myopathies, 65-kd hsp were detected on inflammatory cells, degenerating/regenerating muscle fibers, and non-necrotic muscle fibers invaded by T cells.
- Expression was not uniform across all non-necrotic fibers.
Conclusions:
- 65-kd hsp expression in inflammatory myopathies appears to be an immune-nonspecific response to cellular stress.
- Hsp determinants might also function as autoantigens, potentially recognized by autoreactive T cells.
- Further research is needed to elucidate the precise role of hsp in autoimmune muscle diseases.