Synergistic effect of β-amyloid protein and interferon gamma on nitric oxide production by C2C12 muscle cells

• Published in: Brain (London, England : 1878) England : 1878), 2000-02, Vol.123 (2), p.374-379
• Main Authors: Baron, Pierluigi, Galimberti, Daniela, Meda, Lucia, Prat, Elisabetta, Scarpini, Elio, Conti, Giancarlo, Moggio, Maurizio, Prelle, Alessandro, Scarlato, Guglielmo
• Format: Article
• Language: English
• Subjects: 6′-diamidino-2-phenylindole-dihydrochloride; Amyloid beta-Peptides - pharmacology; Animals; Apoptosis; Aβ = β-amyloid protein; Biological and medical sciences; Cell Line; DAPI = 4; Diseases of striated muscles. Neuromuscular diseases; Gene Expression Regulation; h-IBM = inclusion-body myopathy; IBM; IFN-γ = interferon gamma; Interferon-gamma - pharmacology; L-NMMA = Nω-methyl-L-arginine; Medical sciences; Mice; muscle cell; Muscle, Skeletal - physiopathology; Muscle, Skeletal - ultrastructure; Myositis, Inclusion Body - genetics; Myositis, Inclusion Body - physiopathology; Neurology; nitric oxide; Nitric Oxide - biosynthesis; Nitric Oxide - pharmacology; NO = nitric oxide; NOS = nitric oxide synthase; Oxidative Stress - physiology; s-IBM = inclusion-body myositis; β-amyloid; βAPP = β-amyloid precursor protein
• ISSN: 0006-8950; 1460-2156
• DOI: 10.1093/brain/123.2.374

Nitric oxide (NO) is an important mediator of diverse physiological and pathological responses. NO-induced oxidative stress has been proposed in the pathogenesis of muscle tissue damage in inclusion-body myositis (IBM), which is characterized by deposition of β-amyloid protein (Aβ) in vacuolated muscle fibres. To determine whether Aβ can induce NO production in skeletal muscle, we stimulated C2C12 mouse skeletal muscle cells in vitro with Aβ[1–42] or Aβ[25–35] peptides in the presence or absence of interferon gamma (IFN-γ). Neither Aβ peptides nor IFN-γ were able to stimulate nitrite (NO2–) production by C2C12 cells when given alone. However, combination of IFN-γ with either Aβ[1–42] or Aβ[25–35] resulted in significant NO2– release into cell-free supernatants. Northern blot analysis of RNA obtained from Aβ/IFN-γ-stimulated C2C12 cells revealed increased mRNA accumulation of inducible nitric oxide synthase (iNOS). Moreover, ~4% of muscle cells incubated with Aβ peptides and IFN-γ showed ultrastructural features of DNA fragmentation. These findings, taken together, indicate that the association of Aβ with IFN-γ stimulates NO2– production via induction of iNOS gene expression in skeletal muscle cells, with occasional evidence for nuclear changes suggesting apoptotic morphology. These data further support a role for Aβ deposition in the pathogenesis of postulated oxidative damage in IBM.