transforming-growth-factor-beta and Myositis--Inclusion-Body

Topics: alpha 1-Antichymotrypsin; Amyloid beta-Protein Precursor; Animals; Humans; Low Density Lipoprotein Receptor-Related Protein-1; Muscle Fibers, Skeletal; Myositis, Inclusion Body; Neuromuscular Junction; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Prions; Receptors, Cholinergic; Receptors, LDL; Receptors, Lipoprotein; Superoxide Dismutase; Transforming Growth Factor beta

In this study we aimed to determine whether transforming growth factor-β (TGF-β) signaling is dysregulated in sporadic inclusion body myositis (sIBM) muscle samples.. We examined TGF-β signaling markers in muscle samples from 24 sIBM patients and compared them with those from 10 dermatomyositis (DM) patients using immunohistochemistry and Western blot analyses.. Compared with the DM muscle fibers, the sIBM muscle fibers exhibited greater TGF-β, TGF-β receptor type I (TβRI), and TGF-β receptor type II (TβRII) immunoreactivity in the cytoplasm, as well as greater phosphorylated Smad2 (pSmad2) immunoreactivity in the myonuclei. The signal intensities of TGF-β, TβRI, and TβRII immunoreactivity correlated significantly with muscle fiber cross-sectional areas. Western blot analyses indicated higher expression levels of TGF-β, TβRI, TβRII, and pSmad2 in the sIBM muscle samples than in the DM muscle samples.. These data indicate that upregulation of TGF-β signaling may be an important molecular event in sIBM. Muscle Nerve 55: 741-747, 2017.

Topics: Dermatomyositis; Female; Humans; Male; Muscle, Skeletal; Myositis, Inclusion Body; Phosphorylation; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; Up-Regulation

To investigate expression of vascular endothelial growth factor (VEGF) antiangiogenic isoform A-165b on human muscle in idiopathic inflammatory myopathies (IIM) and to compare distribution of angiogenic/antiangiogenic VEGFs, as isoforms shifts are described in other autoimmune disorders.. We analyzed VEGF-A165b and VEGF-A by western blot and immunohistochemistry on skeletal muscle biopsies from 21 patients affected with IIM (polymyositis, dermatomyositis, and inclusion body myositis) and 6 control muscle samples. TGF- β, a prominent VEGF inductor, was analogously evaluated. Intergroup differences of western blot bands density were statistically examined. Endomysial vascularization, inflammatory score, and muscle regeneration, as pathological parameters of IIM, were quantitatively determined and their levels were confronted with VEGF expression.. VEGF-A165b was significantly upregulated in IIM, as well as TGF- β. VEGF-A was diffusely expressed on unaffected myofibers, whereas regenerating/atrophic myofibres strongly reacted for both VEGF-A isoforms. Most inflammatory cells and endomysial vessels expressed both isoforms. VEGF-A165b levels were in positive correlation to inflammatory score, endomysial vascularization, and TGF- β.. Our findings indicate skeletal muscle expression of antiangiogenic VEGF-A165b and preferential upregulation in IIM, suggesting that modulation of VEGF-A isoforms may occur in myositides.

Topics: Adult; Aged; Blotting, Western; Dermatomyositis; Female; Humans; Immunohistochemistry; Male; Middle Aged; Muscle, Skeletal; Myositis; Myositis, Inclusion Body; Polymyositis; Protein Isoforms; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Topics: Amyloid beta-Protein Precursor; Biopsy; Cell Culture Techniques; Humans; Muscle, Skeletal; Myositis, Inclusion Body; Myostatin; Transforming Growth Factor beta

Myostatin is a negative regulator of muscle mass and strength. Sporadic inclusion-body myositis (s-IBM) is the most common degenerative muscle disease of older persons and is characterized by pronounced muscle wasting. s-IBM is of unknown etiology and pathogenesis, and it lacks definitive treatment. We have now demonstrated in samples from 12 s-IBM biopsies that: (1) by light and electron microscopic immunocytochemistry, myostatin/myostatin precursor is accumulated within muscle fibers and co-localized with amyloid-beta (Abeta); (2) by immunoblots, both myostatin and myostatin precursor are increased; and (3) by immunoprecipitation, myostatin precursor complexes with Abeta. Our study suggests that myostatin/myostatin precursor, either alone, or bound to Abeta, may play a novel role in the pathogenesis of s-IBM.

Topics: Amyloid beta-Peptides; Humans; Immunoblotting; Immunohistochemistry; Immunoprecipitation; Microscopy, Immunoelectron; Muscle, Skeletal; Myositis, Inclusion Body; Myostatin; Transforming Growth Factor beta

We used reverse transcription-polymerase chain reaction to study the level of TGF-beta1 mRNA expression and immunocytochemistry to examine the immunoreactive TGF-beta1 in muscle biopsy specimens from five patients with dermatomyositis (DM) and five patients with inclusion body myositis (IBM) obtained before and after 3 months treatment with intravenous immunoglobulin (IVIg). At baseline, the mRNA expression of TGF-beta1 was increased up to fivefold in the muscles of DM patients compared to that of IBM patients. After IVIg, TGF-beta1 was downregulated and the TGF-beta1 mRNA decreased twofold in the muscles of patients with DM who had successfully responded to therapy, but remained unchanged in the muscles of patients with IBM who did not respond. The downregulation of TGF-beta1 in DM was associated with improvement of the muscle cytoarchitecture and reduction of the endomysial inflammation and connective tissue, suggesting that in DM the excess of TGF-beta1 may be involved in the pathogenesis of chronic inflammation, fibrosis, and accumulation of extracellular matrix proteins.

Topics: Adult; Dermatomyositis; Female; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Immunoglobulins, Intravenous; Immunohistochemistry; Middle Aged; Muscles; Myositis, Inclusion Body; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta

To study cytokine expression in muscle tissues of patients with inflammatory myopathies and to compare the profiles of patients with polymyositis (PM), inclusion body myositis (IBM), and dermatomyositis (DM).. We performed indirect immunohistochemistry studies of muscle tissue sections with a panel of 16 different cytokine-specific monoclonal antibodies, directed against interleukin-1alpha, (IL-1alpha), IL-1beta, IL-1 receptor antagonist (IL-1Ra), IL-2, IL-3, IL-4, IL-6, IL-8, IL-10, IL-13, interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), transforming growth factor beta1 (TGF beta1), TGF beta2, and TGF beta3 in 5 untreated patients each with PM, DM, and IBM and in 4 normal controls. Fresh frozen muscle tissue sections were fixed in formaldehyde before the procedure. The use of saponin as a detergent to permeabilize the cell membranes enabled identification of intracellular cytokine production.. The most prominent finding was the expression of IL-1alpha observed in all patients but in none of the normal controls. In all patients with PM, DM, and IBM, IL-1alpha was expressed in endothelial cells of capillaries, arterioles, and venules in areas surrounded by inflammatory cells, and also in areas with no or scarce inflammatory cells in both endomysium and perimysium. Furthermore, IL-1alpha was also expressed in mononuclear inflammatory cells in all 15 cases. IL-1beta was observed in inflammatory cells in 10 of the 15 patients but, in contrast to IL-1alpha, it was not expressed in blood vessel walls. TGF beta1, TGF beta2, and TGF beta3 were strongly positive in all 15 patients, but only scattered cells were positive in the normal controls. The remaining cytokines were observed only in relatively few cells and only in occasional patients (although the patients were selected for the presence of large infiltrates), and in none of the controls. The patterns were similar in PM, DM, and IBM.. Cytokine expression in muscle tissue of patients with inflammatory myopathy is dominated by IL-1alpha, IL-1beta, and TGF beta1-3. The predominant IL-1alpha expression in the blood vessels indicates an importance of the endothelial cells in the inflammatory process in PM, IBM, and DM. A sustained, local release of T cell-derived cytokines may not be a requirement for tissue injury in the inflammatory myopathies. There does not appear to be a qualitative difference in cytokine expression patterns in PM, IBM, and DM.

Topics: Adult; Aged; Aged, 80 and over; Biopsy; Child; Cytokines; Dermatomyositis; Female; Humans; Immunohistochemistry; Interleukin-1; Lymphokines; Male; Middle Aged; Monokines; Muscles; Myositis; Myositis, Inclusion Body; Polymyositis; Transforming Growth Factor beta