scholarly journals PAI-1–regulated miR-21 defines a novel age-associated fibrogenic pathway in muscular dystrophy

2012 ◽  
Vol 196 (1) ◽  
pp. 163-175 ◽  
Author(s):  
Esther Ardite ◽  
Eusebio Perdiguero ◽  
Berta Vidal ◽  
Susana Gutarra ◽  
Antonio L. Serrano ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Transforming Growth Factor ◽  
Proteolytic Processing ◽  
Mdx Mice ◽  
Muscle Fibrosis ◽  
Type Plasminogen Activator ◽  
Important Regulator ◽  
Muscle Homeostasis ◽  
Phosphatase And Tensin Homologue ◽  
Pai 1

Disruption of skeletal muscle homeostasis by substitution with fibrotic tissue constitutes the principal cause of death in Duchenne muscular dystrophy (DMD) patients, yet the implicated fibrogenic mechanisms remain poorly understood. This study identifies the extracellular PAI-1/urokinase-type plasminogen activator (uPA) balance as an important regulator of microribonucleic acid (miR)–21 biogenesis, controlling age-associated muscle fibrosis and dystrophy progression. Genetic loss of PAI-1 in mdx dystrophic mice anticipated muscle fibrosis through these sequential mechanisms: the alteration of collagen metabolism by uPA-mediated proteolytic processing of transforming growth factor (TGF)–β in muscle fibroblasts and the activation of miR-21 expression, which inhibited phosphatase and tensin homologue and enhanced AKT signaling, thus endowing TGF-β with a remarkable cell proliferation–promoting potential. Age-associated fibrogenesis and muscle deterioration in mdx mice, as well as exacerbated dystrophy in young PAI-1−/− mdx mice, could be reversed by miR-21 or uPA-selective interference, whereas forced miR-21 overexpression aggravated disease severity. The PAI-1–miR-21 fibrogenic axis also appeared dysregulated in muscle of DMD patients, providing a basis for effectively targeting fibrosis and muscular dystrophies in currently untreatable individuals.

scholarly journals Differential Effects of Halofuginone Enantiomers on Muscle Fibrosis and Histopathology in Duchenne Muscular Dystrophy

2021 ◽  
Vol 22 (13) ◽  
pp. 7063
Author(s):  
Sharon Mordechay ◽  
Shaun Smullen ◽  
Paul Evans ◽  
Olga Genin ◽  
Mark Pines ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Motor Coordination ◽  
Mdx Mice ◽  
Cell Viability Assay ◽  
Muscle Fibrosis ◽  
Antifibrotic Therapy ◽  
Racemic Form ◽  
Viability Assay

Progressive loss of muscle and muscle function is associated with significant fibrosis in Duchenne muscular dystrophy (DMD) patients. Halofuginone, an analog of febrifugine, prevents fibrosis in various animal models, including those of muscular dystrophies. Effects of (+)/(−)-halofuginone enantiomers on motor coordination and diaphragm histopathology in mdx mice, the mouse model for DMD, were examined. Four-week-old male mice were treated with racemic halofuginone, or its separate enantiomers, for 10 weeks. Controls were treated with saline. Racemic halofuginone-treated mice demonstrated better motor coordination and balance than controls. However, (+)-halofuginone surpassed the racemic form’s effect. No effect was observed for (−)-halofuginone, which behaved like the control. A significant reduction in collagen content and degenerative areas, and an increase in utrophin levels were observed in diaphragms of mice treated with racemic halofuginone. Again, (+)-halofuginone was more effective than the racemic form, whereas (−)-halofuginone had no effect. Both racemic and (+)-halofuginone increased diaphragm myofiber diameters, with no effect for (−)-halofuginone. No effects were observed for any of the compounds tested in an in-vitro cell viability assay. These results, demonstrating a differential effect of the halofuginone enantiomers and superiority of (+)-halofuginone, are of great importance for future use of (+)-halofuginone as a DMD antifibrotic therapy.

scholarly journals Myostatin promotes a fibrotic phenotypic switch in multipotent C3H 10T1/2 cells without affecting their differentiation into myofibroblasts

2007 ◽  
Vol 196 (2) ◽  
pp. 235-249 ◽  
Author(s):  
Jorge N Artaza ◽  
Rajan Singh ◽  
Monica G Ferrini ◽  
Melissa Braga ◽  
James Tsao ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Plasminogen Activator Inhibitor ◽  
Mouse Cell ◽  
Transforming Growth Factor Β1 ◽  
Negative Regulator ◽  
Public Health Burden ◽  
Muscle Fibrosis ◽  
Differentiated Cells ◽  
Tgf Β1 ◽  
Pai 1

Tissue fibrosis, the excessive deposition of collagen/extracellular matrix combined with the reduction of the cell compartment, defines fibroproliferative diseases, a major cause of death and a public health burden. Key cellular processes in fibrosis include the generation of myofibroblasts from progenitor cells, and the activation or switch of already differentiated cells to a fibrotic synthetic phenotype. Myostatin, a negative regulator of skeletal muscle mass, is postulated to be involved in muscle fibrosis. We have examined whether myostatin affects the differentiation of a multipotent mesenchymal mouse cell line into myofibroblasts, and/or modulates the fibrotic phenotype and Smad expression of the cell population. In addition, we investigated the role of follistatin in this process. Incubation of cells with recombinant myostatin protein did not affect the proportion of myofibroblasts in the culture, but significantly upregulated the expression of fibrotic markers such as collagen and the key profibrotic factors transforming growth factor-β1 (TGF-β1) and plasminogen activator inhibitor (PAI-1), as well as Smad3 and 4, and the pSmad2/3. An antifibrotic process evidenced by the upregulation of follistatin, Smad7, and matrix metalloproteinase 8 accompanied these changes. Follistatin inhibited TGF-β1 induction by myostatin. Transfection with a cDNA expressing myostatin upregulated PAI-1, whereas an shRNA against myostatin blocked this effect. In conclusion, myostatin induced a fibrotic phenotype without significantly affecting differentiation into myofibroblasts. The concurrent endogenous antifibrotic reaction confirms the view that phenotypic switches in multipotent and differentiated cells may affect the progress or reversion of fibrosis, and that myostatin pharmacological inactivation may be a novel therapeutic target against fibrosis.

scholarly journals Sulforaphane mitigates muscle fibrosis in mdx mice via Nrf2-mediated inhibition of TGF-β/Smad signaling

2016 ◽  
Vol 120 (4) ◽  
pp. 377-390 ◽  
Author(s):  
Chengcao Sun ◽  
Shujun Li ◽  
Dejia Li
Keyword(s):  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Mdx Mice ◽  
Related Factor ◽  
Dependent Manner ◽  
Dystrophic Muscle ◽  
Smad Signaling ◽  
Muscle Fibrosis ◽  
Smad Signaling Pathway

Sulforaphane (SFN), an activator of NF-E2-related factor 2 (Nrf2), has been found to have an antifibrotic effect on liver and lung. However, its effects on dystrophic muscle fibrosis remain unknown. This work was undertaken to evaluate the effects of SFN-mediated activation of Nrf2 on dystrophic muscle fibrosis. Male mdx mice (age 3 mo) were treated with SFN by gavage (2 mg/kg body wt per day) for 3 mo. Experimental results demonstrated that SFN remarkably attenuated skeletal and cardiac muscle fibrosis as indicated by reduced Sirius Red staining and immunostaining of the extracellular matrix. Moreover, SFN significantly inhibited the transforming growth factor-β (TGF-β)/Smad signaling pathway and suppressed profibrogenic gene and protein expressions such as those of α-smooth muscle actin (α-SMA), fibronectin, collagen I, plasminogen activator inhibitor-1 (PAI-1), and tissue inhibitor metalloproteinase-1 (TIMP-1) in an Nrf2-dependent manner. Furthermore, SFN significantly decreased the expression of inflammatory cytokines CD45, TNF-α, and IL-6 in mdx mice. In conclusion, these results show that SFN can attenuate dystrophic muscle fibrosis by Nrf2-mediated inhibition of the TGF-β/Smad signaling pathway, which indicates that Nrf2 may represent a new target for dystrophic muscle fibrosis.

scholarly journals Improvement of Endurance of DMD Animal Model Using Natural Polyphenols

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Clementina Sitzia ◽  
Andrea Farini ◽  
Federica Colleoni ◽  
Francesco Fortunato ◽  
Paola Razini ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Genetic Defect ◽  
Premature Death ◽  
Mdx Mice ◽  
Dystrophic Muscle ◽  
Muscle Fibrosis ◽  
Natural Polyphenols ◽  
Dystrophin Deficiency ◽  
Force Reduction ◽  
Muscular Architecture

Duchenne muscular dystrophy (DMD), the most common form of muscular dystrophy, is characterized by muscular wasting caused by dystrophin deficiency that ultimately ends in force reduction and premature death. In addition to primary genetic defect, several mechanisms contribute to DMD pathogenesis. Recently, antioxidant supplementation was shown to be effective in the treatment of multiple diseases including muscular dystrophy. Different mechanisms were hypothesized such as reduced hydroxyl radicals, nuclear factor-κB deactivation, and NO protection from inactivation. Following these promising evidences, we investigated the effect of the administration of a mix of dietary natural polyphenols (ProAbe) on dystrophic mdx mice in terms of muscular architecture and functionality. We observed a reduction of muscle fibrosis deposition and myofiber necrosis together with an amelioration of vascularization. More importantly, the recovery of the morphological features of dystrophic muscle leads to an improvement of the endurance of treated dystrophic mice. Our data confirmed that ProAbe-based diet may represent a strategy to coadjuvate the treatment of DMD.

scholarly journals Osteopontin ablation ameliorates muscular dystrophy by shifting macrophages to a pro-regenerative phenotype

2016 ◽  
Vol 213 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Joana Capote ◽  
Irina Kramerova ◽  
Leonel Martinez ◽  
Sylvia Vetrone ◽  
Elisabeth R. Barton ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Macrophage Polarization ◽  
Inflammatory Cells ◽  
Mdx Mice ◽  
Muscle Weight ◽  
Cell Counts ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
And Function

In the degenerative disease Duchenne muscular dystrophy, inflammatory cells enter muscles in response to repetitive muscle damage. Immune factors are required for muscle regeneration, but chronic inflammation creates a profibrotic milieu that exacerbates disease progression. Osteopontin (OPN) is an immunomodulator highly expressed in dystrophic muscles. Ablation of OPN correlates with reduced fibrosis and improved muscle strength as well as reduced natural killer T (NKT) cell counts. Here, we demonstrate that the improved dystrophic phenotype observed with OPN ablation does not result from reductions in NKT cells. OPN ablation skews macrophage polarization toward a pro-regenerative phenotype by reducing M1 and M2a and increasing M2c subsets. These changes are associated with increased expression of pro-regenerative factors insulin-like growth factor 1, leukemia inhibitory factor, and urokinase-type plasminogen activator. Furthermore, altered macrophage polarization correlated with increases in muscle weight and muscle fiber diameter, resulting in long-term improvements in muscle strength and function in mdx mice. These findings suggest that OPN ablation promotes muscle repair via macrophage secretion of pro-myogenic growth factors.

Regenerating myofibers in tibialis anterior muscles of young ‘MDX’ mice

1987 ◽  
Vol 45 ◽  
pp. 726-727
Author(s):  
H. D. Geissinge ◽  
L.D. Rhodes
Keyword(s):  
Muscular Dystrophy ◽  
Mouse Model ◽  
Tibialis Anterior ◽  
Physiological Activity ◽  
Mdx Mice ◽  
Mode Of Inheritance

A recently discovered mouse model (‘mdx’) for muscular dystrophy in man may be of considerable interest, since the disease in ‘mdx’ mice is inherited by the same mode of inheritance (X-linked) as the human Duchenne (DMD) muscular dystrophy. Unlike DMD, which results in a situation in which the continual muscle destruction cannot keep up with abortive regenerative attempts of the musculature, and the sufferers of the disease die early, the disease in ‘mdx’ mice appears to be transient, and the mice do not die as a result of it. In fact, it has been reported that the severely damaged Tibialis anterior (TA) muscles of ‘mdx’ mice seem to display exceptionally good regenerative powers at 4-6 weeks, so much so, that these muscles are able to regenerate spontaneously up to their previous levels of physiological activity.

Differential Role of Components of the Fibrinolytic System in the Formation and Removal of Thrombus Induced by Endothelial Injury

1999 ◽  
Vol 81 (04) ◽  
pp. 601-604 ◽  
Author(s):  
Hiroyuki Matsuno ◽  
Osamu Kozawa ◽  
Masayuki Niwa ◽  
Shigeru Ueshima ◽  
Osamu Matsuo ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Thrombus Formation ◽  
Endothelial Injury ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
Clot Lysis ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Pai 1

SummaryThe role of fibrinolytic system components in thrombus formation and removal in vivo was investigated in groups of six mice deficient in urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), or plasminogen activator inhibitor-1 (PAI-1) (u-PA-/-, t-PA-/- or PAI-1-/-, respectively) or of their wild type controls (u-PA+/+, t-PA+/+ or PAI-1+/+). Thrombus was induced in the murine carotid artery by endothelial injury using the photochemical reaction between rose bengal and green light (540 nm). Blood flow was continuously monitored for 90 min on day 0 and for 20 min on days 1, 2 and 3. The times to occlusion after the initiation of endothelial injury in u-PA+/+, t-PA+/+ or PAI-1+/+ mice were 9.4 ± 1.3, 9.8 ± 1.1 or 9.7 ± 1.6 min, respectively. u-PA-/- and t-PA-/- mice were indistinguishable from controls, whereas that of PAI-1-/- mice were significantly prolonged (18.4 ± 3.7 min). Occlusion persisted for the initial 90 min observation period in 10 of 18 wild type mice and was followed by cyclic reflow and reocclusion in the remaining 8 mice. At day 1, persistent occlusion was observed in 1 wild type mouse, 8 mice had cyclic reflow and reocclusion and 9 mice had persistent reflow. At day 2, all injured arteries had persistent reflow. Persistent occlusion for 90 min on day 0 was observed in 3 u-PA-/-, in all t-PA-/- mice at day 1 and in 2 of the t-PA-/-mice at day 2 (p <0.01 versus wild type mice). Persistent patency was observed in all PAI-1-/- mice at day 1 and in 5 of the 6 u-PA-/- mice at day 2 (both p <0.05 versus wild type mice). In conclusion, t-PA increases the rate of clot lysis after endothelial injury, PAI-1 reduces the time to occlusion and delays clot lysis, whereas u-PA has little effect on thrombus formation and spontaneous lysis.

A Specific Immunologic Assay for Functional Plasminogen Activator Inhibitor 1 in Plasma – Standardized Measurements of the Inhibitor and Related Parameters in Patients with Venous Thromboembolic Disease

1992 ◽  
Vol 68 (05) ◽  
pp. 486-494 ◽  
Author(s):  
Malou Philips ◽  
Anne-Grethe Juul ◽  
Johan Selmer ◽  
Bent Lind ◽  
Sixtus Thorsen
Keyword(s):  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Normal Subjects ◽  
Tissue Type ◽  
Blood Collection ◽  
Plasminogen Activator Inhibitor 1 ◽  
Type Plasminogen Activator ◽  
Significant Difference ◽  
Activator Inhibitor ◽  
Pai 1

SummaryA new assay for functional plasminogen activator inhibitor 1 (PAI-1) in plasma was developed. The assay is based on the quantitative conversion of PAI-1 to urokinase-type plasminogen activator (u-PA)-PAI-l complex the concentration of which is then determined by an ELISA employing monoclonal anti-PAI-1 as catching antibody and monoclonal anti-u-PA as detecting antibody. The assay exhibits high sensitivity, specificity, accuracy, and precision. The level of functional PAI-1, tissue-type plasminogen activator (t-PA) activity and t-PA-PAI-1 complex was measured in normal subjects and in patients with venous thromboembolism in a silent phase. Blood collection procedures and calibration of the respective assays were rigorously standardized. It was found that the patients had a decreased fibrinolytic capacity. This could be ascribed to high plasma levels of PAI-1. The release of t-PA during venous occlusion of an arm for 10 min expressed as the increase in t-PA + t-PA-PAI-1 complex exhibited great variation and no significant difference could be demonstrated between the patients with a thrombotic tendency and the normal subjects.

Localization of Fibrinolytic Activators and Inhibitors in Normal and Atherosclerotic Vessels

1996 ◽  
Vol 75 (06) ◽  
pp. 933-938 ◽  
Author(s):  
Marten Fålkenberg ◽  
Johan Tjärnstrom ◽  
Per Örtenwall ◽  
Michael Olausson ◽  
Bo Risberg
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Vasa Vasorum ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Tissue Plasminogen ◽  
The Media ◽  
Activator Inhibitor ◽  
Pai 1

SummaryLocal fibrinolytic changes in atherosclerotic arteries have been suggested to influence plaque growth and promote mural thrombosis on ruptured or ulcerated plaques. Increased levels of plasminogen activator inhibitor (PAI-1) have been found in atherosclerotic arteries. In this study tissue plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and PAI-1 were localized in arterial biopsies of healthy and atherosclerotic vessels by immunohistochemis-try. The expression of fibrinolytic regulators was related to the distribution of endothelial cells (EC) and macrophages. Results: t-PA was expressed in vasa vasorum. PAI-1 was positive in endothelial cells, in the media and in the adventitia. Increased expression of t-PA, u-PA and PAI-1 was found in atherosclerotic vessels. t-PA, u-PA, PAI-1 and macrophages were co-localized in plaques. These results support the concept that macrophages can be important in the local regulation of fibrinolysis in atherosclerotic vessels.

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