Publications by authors named "Jill A Rafael-Fortney"

45 Publications

Is Upregulation of Sarcolipin Beneficial or Detrimental to Muscle Function?

Front Physiol 2021 1;12:633058. Epub 2021 Mar 1.

Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.

Sarcolipin (SLN) is a regulator of sarco/endo plasmic reticulum Ca-ATPase (SERCA) pump and has been shown to be involved in muscle nonshivering thermogenesis (NST) and energy metabolism. Interestingly, SLN expression is significantly upregulated both during muscle development and in several disease states. However, the significance of altered SLN expression in muscle patho-physiology is not completely understood. We have previously shown that transgenic over-expression of SLN in skeletal muscle is not detrimental, and can promote oxidative metabolism and exercise capacity. In contrast, some studies have suggested that SLN upregulation in disease states is deleterious for muscle function and ablation of SLN can be beneficial. In this perspective article, we critically examine both published and some new data to determine the relevance of SLN expression to disease pathology. The new data presented in this paper show that SLN levels are induced in muscle during systemic bacterial () infection or lipopolysaccharides (LPS) treatment. We also present data showing that SLN expression is significantly upregulated in different types of muscular dystrophies including myotubular myopathy. These data taken together reveal that upregulation of SLN expression in muscle disease is progressive and increases with severity. Therefore, we suggest that increased SLN expression should not be viewed as the cause of the disease; rather, it is a compensatory response to meet the higher energy demand of the muscle. We interpret that higher SLN/SERCA ratio positively modulate cytosolic Ca signaling pathways to promote mitochondrial biogenesis and oxidative metabolism to meet higher energy demand in muscle.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2021.633058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7956958PMC
March 2021

Micro-dystrophin gene therapy prevents heart failure in an improved Duchenne muscular dystrophy cardiomyopathy mouse model.

JCI Insight 2021 Apr 8;6(7). Epub 2021 Apr 8.

Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA.

Gene replacement for Duchenne muscular dystrophy (DMD) with micro-dystrophins has entered clinical trials, but efficacy in preventing heart failure is unknown. Although most patients with DMD die from heart failure, cardiomyopathy is undetectable until the teens, so efficacy from trials in young boys will be unknown for a decade. Available DMD animal models were sufficient to demonstrate micro-dystrophin efficacy on earlier onset skeletal muscle pathology underlying loss of ambulation and respiratory insufficiency in patients. However, no mouse models progressed into heart failure, and dog models showed highly variable progression insufficient to evaluate efficacy of micro-dystrophin or other therapies on DMD heart failure. To overcome this barrier, we have generated the first DMD mouse model to our knowledge that reproducibly progresses into heart failure. This model shows cardiac inflammation and fibrosis occur prior to reduced function. Fibrosis does not continue to accumulate, but inflammation persists after function declines. We used this model to test micro-dystrophin gene therapy efficacy on heart failure prevention for the first time. Micro-dystrophin prevented declines in cardiac function and prohibited onset of inflammation and fibrosis. This model will allow identification of committed pathogenic steps to heart failure and testing of genetic and nongenetic therapies to optimize cardiac care for patients with DMD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.146511DOI Listing
April 2021

Early Inflammation in Muscular Dystrophy Differs between Limb and Respiratory Muscles and Increases with Dystrophic Severity.

Am J Pathol 2021 04 23;191(4):730-747. Epub 2021 Jan 23.

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio; Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio. Electronic address:

Duchenne muscular dystrophy (DMD) is a genetic, degenerative, striated muscle disease exacerbated by chronic inflammation. Mdx mice in the genotypic DMD model poorly represent immune-mediated pathology observed in patients. Improved understanding of innate immunity in dystrophic muscles is required to develop specific anti-inflammatory treatments. Here, inflammation in mdx mice and the more fibrotic utrn;mdx Het model was comprehensively investigated. Unbiased analysis showed that mdx and Het mice contain increased levels of numerous chemokines and cytokines, with further increased in Het mice. Chemokine and chemokine receptor gene expression levels were dramatically increased in 4-week-old dystrophic quadriceps muscles, and to a lesser extent in diaphragm during the early injury phase, and had a small but consistent increase at 8 and 20 weeks. An optimized direct immune cell isolation method prevented loss of up to 90% of macrophages with density-dependent centrifugation previously used for mdx flow cytometry. Het quadriceps contain higher proportions of neutrophils and infiltrating monocytes than mdx, and higher percentages of F4/80, but lower percentages of F4/80 cells and patrolling monocytes compared with Het diaphragms. These differences may restrict regenerative potential of dystrophic diaphragms, increasing pathologic severity. Fibrotic and inflammatory gene expression levels are higher in myeloid cells isolated from Het compared with mdx quadriceps, supporting Het mice may represent an improved model for testing therapeutic manipulation of inflammation in DMD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajpath.2021.01.008DOI Listing
April 2021

Muscle Twitch Kinetics Are Dependent on Muscle Group, Disease State, and Age in Duchenne Muscular Dystrophy Mouse Models.

Front Physiol 2020 25;11:568909. Epub 2020 Sep 25.

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States.

Duchenne muscular dystrophy (DMD) is an X-linked disorder caused by the lack of functional dystrophin protein. In muscular dystrophy preclinical research, it is pertinent to analyze the force of the muscles affected by the disease to assess pathology and potential effectiveness of therapeutic interventions. Although muscles function at sub-maximal levels , maximal tetanic contractions are most commonly used to assess and report muscle function in muscular dystrophy studies. At submaximal activation, the kinetics of contraction and relaxation are heavily impacted by the kinetics of the single twitch. However, maximal tetanic force is often the main, if not sole, outcome measured in most studies, while contractile kinetics are rarely reported. To investigate the effect of muscle disease on twitch contraction kinetics, isolated diaphragm and (EDL) muscles of 10-, 20-week, "het" (dystrophin deficient and utrophin haplo-insufficient), and 52-week (dystrophin deficient) mice were analyzed and compared to wild-type controls. We observed that twitch contractile kinetics are dependent on muscle type, age, and disease state. Specific findings include that diaphragm from wildtype mice has a greater time to 50% relaxation (RT50) than time to peak tension (TTP) compared to the het and dystrophic models, where there is a similar TTP compared to RT50. Diaphragm twitch kinetics remain virtually unchanged with age, while the EDL from het and mice initially has a greater RT50 than TTP, but the TTP increases with age. The difference between EDL contractile kinetics of dystrophic and wildtype mice is more prominent at young age. Differences in kinetics yielded greater statistical significance compared to previously published force measurements, thus, using kinetics as an outcome parameter could potentially allow for use of smaller experimental groups in future study designs. Although this study focused on DMD models, our findings may be applicable to other skeletal muscle conditions and diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2020.568909DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7545010PMC
September 2020

Mineralocorticoid receptor antagonism by finerenone is sufficient to improve function in preclinical muscular dystrophy.

ESC Heart Fail 2020 Sep 18. Epub 2020 Sep 18.

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.

Aims: Duchenne muscular dystrophy (DMD) is an X-linked inherited disease due to dystrophin deficiency causing skeletal and cardiac muscle dysfunction. Affected patients lose ambulation by age 12 and usually die in the second to third decades of life from cardiac and respiratory failure. Symptomatic treatment includes the use of anti-inflammatory corticosteroids, which are associated with side effects including weight gain, osteoporosis, and increased risk of cardiovascular disease. Novel treatment options include blockade of the renin-angiotensin-aldosterone system, because angiotensin as well as aldosterone contribute to persistent inflammation and fibrosis, and aldosterone blockade represents an efficacious anti-fibrotic approach in cardiac failure. Recent preclinical findings enabled successful clinical testing of a combination of steroidal mineralocorticoid receptor antagonists (MRAs) and angiotensin converting enzyme inhibitors in DMD boys. The efficacy of MRAs alone on dystrophic skeletal muscle and heart has not been investigated. Here, we tested efficacy of the novel non-steroidal MRA finerenone as a monotherapy in a preclinical DMD model.

Methods And Results: The dystrophin-deficient, utrophin haploinsufficient mouse model of DMD was treated with finerenone and compared with untreated dystrophic and wild-type controls. Grip strength, electrocardiography, cardiac magnetic resonance imaging, muscle force measurements, histological quantification, and gene expression studies were performed. Finerenone treatment alone resulted in significant improvements in clinically relevant functional parameters in both skeletal muscle and heart. Normalized grip strength in rested dystrophic mice treated with finerenone (40.3 ± 1.0 mN/g) was significantly higher (P = 0.0182) compared with untreated dystrophic mice (35.2 ± 1.5 mN/g). Fatigued finerenone-treated dystrophic mice showed an even greater relative improvement (P = 0.0003) in normalized grip strength (37.5 ± 1.1 mN/g) compared with untreated mice (29.7 ± 1.1 mN/g). Finerenone treatment also led to significantly lower (P = 0.0075) susceptibility to limb muscle damage characteristic of DMD measured during a contraction-induced injury protocol. Normalized limb muscle force after five lengthening contractions resulted in retention of 71 ± 7% of baseline force in finerenone-treated compared with only 51 ± 4% in untreated dystrophic mice. Finerenone treatment also prevented significant reductions in myocardial strain rate (P = 0.0409), the earliest sign of DMD cardiomyopathy. Moreover, treatment with finerenone led to very specific cardiac gene expression changes in clock genes that might modify cardiac pathophysiology in this DMD model.

Conclusions: Finerenone administered as a monotherapy is disease modifying for both skeletal muscle and heart in a preclinical DMD model. These findings support further evaluation of finerenone in DMD clinical trials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ehf2.12996DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7754779PMC
September 2020

Mineralocorticoid Receptor Signaling Contributes to Normal Muscle Repair After Acute Injury.

Front Physiol 2019 25;10:1324. Epub 2019 Oct 25.

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States.

Acute skeletal muscle injury is followed by a temporal response of immune cells, fibroblasts, and muscle progenitor cells within the muscle microenvironment to restore function. These same cell types are repeatedly activated in muscular dystrophy from chronic muscle injury, but eventually, the regenerative portion of the cycle is disrupted and fibrosis replaces degenerated muscle fibers. Mineralocorticoid receptor (MR) antagonist drugs have been demonstrated to increase skeletal muscle function, decrease fibrosis, and directly improve membrane integrity in muscular dystrophy mice, and therefore are being tested clinically. Conditional knockout of MR from muscle fibers in muscular dystrophy mice also improves skeletal muscle function and decreases fibrosis. The mechanism of efficacy likely results from blocking MR signaling by its endogenous agonist aldosterone, being produced at high local levels in regions of muscle damage by infiltrating myeloid cells. Since chronic and acute injuries share the same cellular processes to regenerate muscle, and MR antagonists are clinically used for a wide variety of conditions, it is crucial to define the role of MR signaling in normal muscle repair after injury. In this study, we performed acute injuries using barium chloride injections into muscles both in myofiber MR conditional knockout mice on a wild-type background (MRcko) and in MR antagonist-treated wild-type mice. Steps of the muscle regeneration response were analyzed at 1, 4, 7, or 14 days after injury. Presence of the aldosterone synthase enzyme was also assessed during the injury repair process. We show for the first time aldosterone synthase localization in infiltrating immune cells of normal skeletal muscle after acute injury. MRcko mice had an increased muscle area infiltrated by aldosterone synthase positive myeloid cells compared to control injured animals. Both MRcko and MR antagonist treatment stabilized damaged myofibers and increased collagen infiltration or compaction at 4 days post-injury. MR antagonist treatment also led to reduced myofiber size at 7 and 14 days post-injury. These data support that MR signaling contributes to the normal muscle repair process following acute injury. MR antagonist treatment delays muscle fiber growth, so temporary discontinuation of these drugs after a severe muscle injury could be considered.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2019.01324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6830343PMC
October 2019

Mineralocorticoid receptor antagonists improve membrane integrity independent of muscle force in muscular dystrophy.

Hum Mol Genet 2019 06;28(12):2030-2045

Department of Physiology and Cell Biology.

Mineralocorticoid receptor (MR) drugs have been used clinically for decades to treat cardiovascular diseases. MR antagonists not only show preclinical efficacy for heart in Duchenne muscular dystrophy (DMD) models but also improve skeletal muscle force and muscle membrane integrity. The mechanisms of action of MR antagonists in skeletal muscles are entirely unknown. Since MR are present in many cell types in the muscle microenvironment, it is critical to define cell-intrinsic functions in each cell type to ultimately optimize antagonist efficacy for use in the widest variety of diseases. We generated a new conditional knockout of MR in myofibers and quantified cell-intrinsic mechanistic effects on functional and histological parameters in a DMD mouse model. Skeletal muscle MR deficiency led to improved respiratory muscle force generation and less deleterious fibrosis but did not reproduce MR antagonist efficacy on membrane susceptibility to induced damage. Surprisingly, acute application of MR antagonist to muscles led to improvements in membrane integrity after injury independent of myofiber MR. These data demonstrate that MR antagonists are efficacious to dystrophic skeletal muscles through both myofiber intrinsic effects on muscle force and downstream fibrosis and extrinsic functions on membrane stability. MR antagonists may therefore be applicable for treating more general muscle weakness and possibly other conditions that result from cell injuries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddz039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548225PMC
June 2019

Mineralocorticoid Receptor Antagonists in Muscular Dystrophy Mice During Aging and Exercise.

J Neuromuscul Dis 2018;5(3):295-306

Department of Physiology & Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA.

Background: Mineralocorticoid receptor antagonists added to angiotensin converting enzyme inhibitors have shown preclinical efficacy for both skeletal and cardiac muscle outcomes in young sedentary dystrophin-deficient mdx mice also haploinsufficient for utrophin, a Duchenne muscular dystrophy (DMD) model. The mdx genotypic DMD model has mild pathology, making non-curative therapeutic effects difficult to distinguish at baseline. Since the cardiac benefit of mineralocorticoid receptor antagonists has been translated to DMD patients, it is important to optimize potential advantages for skeletal muscle by further defining efficacy parameters.

Objective: We aimed to test whether therapeutic effects of mineralocorticoid receptor antagonists added to angiotensin converting enzyme inhibitors are detectable using three different reported methods of exacerbating the mdx phenotype.

Methods: We tested treatment with lisinopril and the mineralocorticoid receptor antagonist spironolactone in: 10 week-old exercised, 1 year-old sedentary, and 5 month-old isoproterenol treated mdx mice and performed comprehensive functional and histological measurements.

Results: None of the protocols to exacerbate mdx phenotypes resulted in dramatically enhanced pathology and no significant benefit was observed with treatment.

Conclusions: Since endogenous mineralocorticoid aldosterone production from immune cells in dystrophic muscle may explain antagonist efficacy, it is likely that these drugs work optimally during the narrow window of peak inflammation in mdx mice. Exercised and aged mdx mice do not display prolific damage and inflammation, likely explaining the absence of continued efficacy of these drugs. Since inflammation is more prevalent in DMD patients, the therapeutic window for mineralocorticoid receptor antagonists in patients may be longer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3233/JND-180323DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6732783PMC
November 2018

Gene expression effects of glucocorticoid and mineralocorticoid receptor agonists and antagonists on normal human skeletal muscle.

Physiol Genomics 2017 Jun 21;49(6):277-286. Epub 2017 Apr 21.

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio;

Mineralocorticoid and glucocorticoid receptors are closely related steroid hormone receptors that regulate gene expression through many of the same hormone response elements. However, their transcriptional activities and effects in skeletal muscles are largely unknown. We recently identified mineralocorticoid receptors (MR) in skeletal muscles after finding that combined treatment with the angiotensin-converting enzyme inhibitor lisinopril and MR antagonist spironolactone was therapeutic in Duchenne muscular dystrophy mouse models. The glucocorticoid receptor (GR) agonist prednisolone is the current standard-of-care treatment for Duchenne muscular dystrophy because it prolongs ambulation, likely due to its anti-inflammatory effects. However, data on whether glucocorticoids have a beneficial or detrimental direct effect on skeletal muscle are controversial. Here, we begin to define the gene expression profiles in normal differentiated human skeletal muscle myotubes treated with MR and GR agonists and antagonists. The MR agonist aldosterone and GR agonist prednisolone had highly overlapping gene expression profiles, supporting the notion that prednisolone acts as both a GR and MR agonist that may have detrimental effects on skeletal muscles. Co-incubations with aldosterone plus either nonspecific or selective MR antagonists, spironolactone or eplerenone, resulted in similar numbers of gene expression changes, suggesting that both drugs can block MR activation to a similar extent. Eplerenone treatment alone decreased a number of important muscle-specific genes. This information may be used to develop biomarkers to monitor clinical efficacy of MR antagonists or GR agonists in muscular dystrophy, develop a temporally coordinated treatment with both drugs, or identify novel therapeutics with more specific downstream targets.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/physiolgenomics.00128.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5495910PMC
June 2017

Myocardial Contractile Dysfunction Is Present without Histopathology in a Mouse Model of Limb-Girdle Muscular Dystrophy-2F and Is Prevented after Claudin-5 Virotherapy.

Front Physiol 2016 6;7:539. Epub 2016 Dec 6.

Department of Physiology and Cell Biology, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical CenterColumbus, OH, USA.

Mutations in several members of the dystrophin glycoprotein complex lead to skeletal and cardiomyopathies. Cardiac care for these muscular dystrophies consists of management of symptoms with standard heart medications after detection of reduced whole heart function. Recent evidence from both Duchenne muscular dystrophy patients and animal models suggests that myocardial dysfunction is present before myocardial damage or deficiencies in whole heart function, and that treatment prior to heart failure symptoms may be beneficial. To determine whether this same early myocardial dysfunction is present in other muscular dystrophy cardiomyopathies, we conducted a physiological assessment of cardiac function at the tissue level in the δ-sarcoglycan null mouse model () of Limb-girdle muscular dystrophy type 2F. Baseline cardiac contractile force measurements using intact linear muscle preparations, were severely depressed in these mice without the presence of histopathology. Virotherapy withclaudin-5 prevents the onset of cardiomyopathy in another muscular dystrophy model. After virotherapy with claudin-5, the cardiac contractile force deficits in mice are no longer significant. These studies suggest that screening Limb-girdle muscular dystrophy patients using methods that detect earlier functional changes may provide a longer therapeutic window for cardiac care.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2016.00539DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138189PMC
December 2016

Renin-angiotensin-aldosterone system inhibitors improve membrane stability and change gene-expression profiles in dystrophic skeletal muscles.

Am J Physiol Cell Physiol 2017 Feb 23;312(2):C155-C168. Epub 2016 Nov 23.

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio; and

Angiotensin-converting enzyme inhibitors (ACEi) and mineralocorticoid receptor (MR) antagonists are FDA-approved drugs that inhibit the renin-angiotensin-aldosterone system (RAAS) and are used to treat heart failure. Combined treatment with the ACEi lisinopril and the nonspecific MR antagonist spironolactone surprisingly improves skeletal muscle, in addition to heart function and pathology in a Duchenne muscular dystrophy (DMD) mouse model. We recently demonstrated that MR is present in all limb and respiratory muscles and functions as a steroid hormone receptor in differentiated normal human skeletal muscle fibers. The goals of the current study were to begin to define cellular and molecular mechanisms mediating the skeletal muscle efficacy of RAAS inhibitor treatment. We also compared molecular changes resulting from RAAS inhibition with those resulting from the current DMD standard-of-care glucocorticoid treatment. Direct assessment of muscle membrane integrity demonstrated improvement in dystrophic mice treated with lisinopril and spironolactone compared with untreated mice. Short-term treatments of dystrophic mice with specific and nonspecific MR antagonists combined with lisinopril led to overlapping gene-expression profiles with beneficial regulation of metabolic processes and decreased inflammatory gene expression. Glucocorticoids increased apoptotic, proteolytic, and chemokine gene expression that was not changed by RAAS inhibitors in dystrophic mice. Microarray data identified potential genes that may underlie RAAS inhibitor treatment efficacy and the side effects of glucocorticoids. Direct effects of RAAS inhibitors on membrane integrity also contribute to improved pathology of dystrophic muscles. Together, these data will inform clinical development of MR antagonists for treating skeletal muscles in DMD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajpcell.00269.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5336592PMC
February 2017

Similar efficacy from specific and non-specific mineralocorticoid receptor antagonist treatment of muscular dystrophy mice.

J Neuromuscul Dis 2016 ;3(3):395-404

Department of Physiology & Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA.

Background: Combined treatment with an angiotensin-converting enzyme inhibitor and a mineralocorticoid receptor (MR) antagonist improved cardiac and skeletal muscle function and pathology in a mouse model of Duchenne muscular dystrophy. MR is present in limb and respiratory skeletal muscles and functions as a steroid hormone receptor.

Objective: The goals of the current study were to compare the efficacy of the specific MR antagonist eplerenone with the non-specific MR antagonist spironolactone, both in combination with the angiotensin-converting enzyme inhibitor lisinopril.

Methods: Three groups of n=18 dystrophin-deficient, utrophin-haploinsufficient male mice were given chow containing: lisinopril plus spironolactone, lisinopril plus eplerenone, or no drug, from four to 20 weeks-of-age. Eighteen C57BL/10 male mice were used as wild-type controls. measurements included cardiac magnetic resonance imaging, conscious electrocardiography, and grip strength. From each mouse in the study, diaphragm, , and cardiac papillary muscle force was measured , followed by histological quantification of muscle damage in heart, diaphragm, quadriceps, and abdominal muscles. MR protein levels were also verified in treated muscles.

Results: Treatment with specific and non-specific MR antagonists did not result in any adverse effects to dystrophic skeletal muscles or heart. Both treatments resulted in similar functional and pathological improvements across a wide array of parameters. MR protein levels were not reduced by treatment.

Conclusions: These data suggest that spironolactone and eplerenone show similar effects in dystrophic mice and support the clinical development of MR antagonists for treating skeletal muscles in Duchenne muscular dystrophy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3233/JND-160173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5096836PMC
March 2018

Myeloid cells are capable of synthesizing aldosterone to exacerbate damage in muscular dystrophy.

Hum Mol Genet 2016 12;25(23):5167-5177

Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA.

FDA-approved mineralocorticoid receptor (MR) antagonists are used to treat heart failure. We have recently demonstrated efficacy of MR antagonists for skeletal muscles in addition to heart in Duchenne muscular dystrophy mouse models and that mineralocorticoid receptors are present and functional in skeletal muscles. The goal of this study was to elucidate the underlying mechanisms of MR antagonist efficacy on dystrophic skeletal muscles. We demonstrate for the first time that infiltrating myeloid cells clustered in damaged areas of dystrophic skeletal muscles have the capacity to produce the natural ligand of MR, aldosterone, which in excess is known to exacerbate tissue damage. Aldosterone synthase protein levels are increased in leukocytes isolated from dystrophic muscles compared with controls and local aldosterone levels in dystrophic skeletal muscles are increased, despite normal circulating levels. All genes encoding enzymes in the pathway for aldosterone synthesis are expressed in muscle-derived leukocytes. 11β-HSD2, the enzyme that inactivates glucocorticoids to increase MR selectivity for aldosterone, is also increased in dystrophic muscle tissues. These results, together with the demonstrated preclinical efficacy of antagonists, suggest MR activation is in excess of physiological need and likely contributes to the pathology of muscular dystrophy. This study provides new mechanistic insight into the known contribution of myeloid cells to muscular dystrophy pathology. This first report of myeloid cells having the capacity to produce aldosterone may have implications for a wide variety of acute injuries and chronic diseases with inflammation where MR antagonists may be therapeutic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddw331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6078642PMC
December 2016

Duchenne Muscular Dystrophy Mice and Men: Can Understanding a Genetic Cardiomyopathy Inform Treatment of Other Myocardial Diseases?

Circ Res 2016 Apr;118(7):1059-61

From the Department of Physiology and Cell Biology (J.A.R.-F., J.A.C.), Division of Cardiovascular Medicine, Department of Internal Medicine (S.V.R.), College of Medicine and Wexner Medical Center, The Ohio State University, Columbus.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCRESAHA.116.308402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4819164PMC
April 2016

Rationally engineered Troponin C modulates in vivo cardiac function and performance in health and disease.

Nat Commun 2016 Feb 24;7:10794. Epub 2016 Feb 24.

Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Columbus, Ohio 43210, USA.

Treatment for heart disease, the leading cause of death in the world, has progressed little for several decades. Here we develop a protein engineering approach to directly tune in vivo cardiac contractility by tailoring the ability of the heart to respond to the Ca(2+) signal. Promisingly, our smartly formulated Ca(2+)-sensitizing TnC (L48Q) enhances heart function without any adverse effects that are commonly observed with positive inotropes. In a myocardial infarction (MI) model of heart failure, expression of TnC L48Q before the MI preserves cardiac function and performance. Moreover, expression of TnC L48Q after the MI therapeutically enhances cardiac function and performance, without compromising survival. We demonstrate engineering TnC can specifically and precisely modulate cardiac contractility that when combined with gene therapy can be employed as a therapeutic strategy for heart disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ncomms10794DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4770086PMC
February 2016

Standard Operating Procedures (SOPs) for Evaluating the Heart in Preclinical Studies of Duchenne Muscular Dystrophy.

J Cardiovasc Transl Res 2016 Feb 30;9(1):85-6. Epub 2015 Dec 30.

Parent Project Muscular Dystrophy, Middletown, OH, USA.

A recent working group meeting focused on contemporary cardiac issues in Duchenne muscular dystrophy (DMD) was hosted by the National Heart, Lung, and Blood Institute in collaboration with the Parent Project Muscular Dystrophy. An outcome of this meeting was to provide freely available detailed protocols for preclinical animal studies. The goal of these protocols is to improve the quality and reproducibility of cardiac preclinical studies aimed at developing new therapeutics for the prevention and treatment of DMD cardiomyopathy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12265-015-9669-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5509361PMC
February 2016

Muscle damage, metabolism, and oxidative stress in mdx mice: Impact of aerobic running.

Muscle Nerve 2016 06;54(1):110-7

Department of Human Sciences, Kinesiology Program, The Ohio State University, Columbus, Ohio, USA.

Introduction: We tested how a treadmill exercise program influences oxygen consumption, oxidative stress, and exercise capacity in the mdx mouse, a model of Duchenne muscular dystrophy.

Methods: At age 4 weeks mdx mice were subjected to 4 weeks of twice-weekly treadmill exercise. Sedentary mdx and wild-type mice served as controls. Oxygen consumption, time to exhaustion, oxidative stress, and myofiber damage were assessed.

Results: At age 4 weeks, there was a significant difference in exercise capacity between mdx and wild-type mice. After exercise, mdx mice had lower basal oxygen consumption and exercise capacity, but similar maximal oxygen consumption. Skeletal muscle from these mice displayed increased oxidative stress. Collagen deposition was higher in exercised versus sedentary mice.

Conclusions: Exercised mdx mice exhibit increased oxidative stress, as well as deficits in exercise capacity, baseline oxygen consumption, and increased myofiber fibrosis. Muscle Nerve 54: 110-117, 2016.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mus.25015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4905810PMC
June 2016

Mineralocorticoid receptors are present in skeletal muscle and represent a potential therapeutic target.

FASEB J 2015 Nov 15;29(11):4544-54. Epub 2015 Jul 15.

*Department of Molecular and Cellular Biochemistry, Department of Physiology and Cell Biology, Department of Molecular Virology, Immunology, and Medical Genetics College of Medicine, The Ohio State University, Columbus, Ohio, USA; and Department of Internal Medicine and Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, USA

Early treatment with heart failure drugs lisinopril and spironolactone improves skeletal muscle pathology in Duchenne muscular dystrophy (DMD) mouse models. The angiotensin converting enzyme inhibitor lisinopril and mineralocorticoid receptor (MR) antagonist spironolactone indirectly and directly target MR. The presence and function of MR in skeletal muscle have not been explored. MR mRNA and protein are present in all tested skeletal muscles from both wild-type mice and DMD mouse models. MR expression is cell autonomous in both undifferentiated myoblasts and differentiated myotubes from mouse and human skeletal muscle cultures. To test for MR function in skeletal muscle, global gene expression analysis was conducted on human myotubes treated with MR agonist (aldosterone; EC50 1.3 nM) or antagonist (spironolactone; IC50 1.6 nM), and 53 gene expression differences were identified. Five differences were conserved in quadriceps muscles from dystrophic mice treated with spironolactone plus lisinopril (IC50 0.1 nM) compared with untreated controls. Genes down-regulated more than 2-fold by MR antagonism included FOS, ANKRD1, and GADD45B, with known roles in skeletal muscle, in addition to NPR3 and SERPINA3, bona fide targets of MR in other tissues. MR is a novel drug target in skeletal muscle and use of clinically safe antagonists may be beneficial for muscle diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1096/fj.15-276782DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4608910PMC
November 2015

Contemporary cardiac issues in Duchenne muscular dystrophy. Working Group of the National Heart, Lung, and Blood Institute in collaboration with Parent Project Muscular Dystrophy.

Circulation 2015 May;131(18):1590-8

From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (E.M.M.); Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (J.R.K., G.D.P.); Division of Cardiology, Children's Hospital of Wisconsin, Milwaukee (D.W.B.); Department of Pediatrics, Washington University, St. Louis, MO (C.E.C.); The Heart Center, Nationwide Children's Hospital, Columbus, OH (L.H.C., N.K.); Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia (D.D.); Division of Pulmonary Medicine, Children's Hospital of Pittsburgh, PA (J.D.F.); Center for Genetic Medicine Research (E.P.H.) and Division of Cardiology, Children's National Heart Institute, Center for Genetic Medicine Research (C.F.S.), Children's National Health System, Washington, DC; Division of Cardiology, Johns Hopkins School of Medicine, Baltimore, MD (D.P.J.); Parent Project Muscular Dystrophy, Middletown, OH (K.K.); Division of Cardiac Critical Care, Children's Hospital of Philadelphia, PA (R.K.); Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis (J.M.M.); Department of Molecular and Cellular Biochemistry (J.A.R.-F.) and Division of Cardiovascular Medicine (S.V.R.), Ohio State University, Columbus; Division of Cardiovascular and Renal Products, US Food and Drug Administration, Silver Spring, MD (S.L.T.); Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD (K.R.W.); and Division of Pediatric Cardiology, Department of Pediatrics, Vanderbilt University, Nashville, TN (L.W.M.).

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCULATIONAHA.114.015151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573596PMC
May 2015

Eplerenone for early cardiomyopathy in Duchenne muscular dystrophy: a randomised, double-blind, placebo-controlled trial.

Lancet Neurol 2015 Feb 30;14(2):153-61. Epub 2014 Dec 30.

Nationwide Children's Hospital, Columbus, OH, USA.

Background: Cardiomyopathy is a leading cause of death in patients with Duchenne muscular dystrophy and myocardial damage precedes decline in left ventricular systolic function. We tested the efficacy of eplerenone on top of background therapy in patients with Duchenne muscular dystrophy with early myocardial disease.

Methods: In this randomised, double-blind, placebo-controlled trial, boys from three centres in the USA aged 7 years or older with Duchenne muscular dystrophy, myocardial damage by late gadolinium enhancement cardiac MRI and preserved ejection fraction received either eplerenone 25 mg or placebo orally, every other day for the first month and once daily thereafter, in addition to background clinician-directed therapy with either angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB). Computer-generated randomisation was done centrally using block sizes of four and six, and only the study statistician and the investigational pharmacy had the preset randomisation assignments. The primary outcome was change in left ventricular circumferential strain (Ecc) at 12 months, a measure of contractile dysfunction. Safety was established through serial serum potassium levels and measurement of cystatin C, a non-creatinine measure of kidney function. This trial is registered with ClinicalTrials.gov, number NCT01521546.

Findings: Between Jan 26, 2012, and July 3, 2013, 188 boys were screened and 42 were enrolled. 20 were randomly assigned to receive eplerenone and 22 to receive placebo, of whom 20 in the eplerenone group and 20 in the placebo group completed baseline, 6-month, and 12-month visits. After 12 months, decline in left ventricular circumferential strain was less in those who received eplerenone than in those who received placebo (median ΔEcc 1·0 [IQR 0·3-2·2] vs 2·2 [1·3-3·1]; p=0·020). Cystatin C concentrations remained normal in both groups, and all non-haemolysed blood samples showed normal potassium concentrations. One 23-year-old patient in the placebo group died of fat embolism, and another patient in the placebo group withdrew from the trial to address long-standing digestive issues. All other adverse events were mild: short-lived headaches coincident with seasonal allergies occurred in one patient given eplerenone, flushing occurred in one patient given placebo, and anxiety occurred in another patient given placebo.

Interpretation: In boys with Duchenne muscular dystrophy and preserved ejection fraction, addition of eplerenone to background ACEI or ARB therapy attenuates the progressive decline in left ventricular systolic function. Early use of available drugs warrants consideration in this population at high risk of cardiac death, but further studies are needed to determine the effect of combination cardioprotective therapy on event-free survival in Duchenne muscular dystrophy.

Funding: BallouSkies, Parent Project for Muscular Dystrophy, US National Center for Advancing Translational Sciences, and US National Institutes of Health.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1474-4422(14)70318-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361281PMC
February 2015

The Angiotensin Converting Enzyme Inhibitor Lisinopril Improves Muscle Histopathology but not Contractile Function in a Mouse Model of Duchenne Muscular Dystrophy.

J Neuromuscul Dis 2015;2(3):257-268. Epub 2015 Sep 2.

Department of Physiology & Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA ; Department of Molecular & Cellular Biochemistry, The Ohio State University, Columbus, OH, USA.

Background: Angiotensin converting enzyme inhibitors (ACEi) are the current standard of care treatment for cardiac dysfunction in Duchenne muscular dystrophy patients. We previously showed treatment with an ACEi plus mineralocorticoid receptor (MR) antagonist improves limb and respiratory skeletal muscles, in addition to cardiac muscles, in a dystrophic mouse model at 20 weeks-of-age.

Objective: To determine whether previously observed preclinical benefits of an ACEi plus MR antagonist on dystrophic skeletal muscles can be reproduced by increasing ACEi dosage alone. We also compared functional and histological outcome measures at 10 and 20 weeks-of-age.

Methods: Dystrophin deficient utrophin haplo-insufficient (; ) "het" mice were treated with 10, 20, or 50 mg/kg × day of the ACEi lisinopril from 4 to 10 weeks-of-age via water bottles and compared with C57BL/10 wild-type control mice and untreated hets. Data from 10 week-old het mice were also compared to data collected from an untreated het group at 20 weeks-old. cardiac and grip strength measurements, diaphragm and muscle force measurements, and histopathological analyses were performed. One-way ANOVA followed by Dunnett comparison was used to determine significance.

Results: ACEi treatment reduced skeletal muscle damage but had no significant effect on muscle force. Body weight, heart rate, grip strength and blood pressure were unaffected by treatment. Limb muscle histopathology was more informative at 10 than 20 weeks-of-age.

Conclusions: These results suggest increased ACEi dosage alone cannot improve all dystrophic parameters. Further optimization of MR antagonists in 20 week-old mice is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3233/JND-150099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838202PMC
September 2015

Claudin-5 levels are reduced from multiple cell types in human failing hearts and are associated with mislocalization of ephrin-B1.

Cardiovasc Pathol 2015 May-Jun;24(3):160-167. Epub 2014 Nov 7.

Dept. of Molecular & Cellular Biochemistry, The Ohio State University, Columbus, OH 43210.

Claudin-5 is transcriptionally downregulated resulting in dramatically reduced protein levels in human heart failure. Studies in mice have demonstrated that reduced claudin-5 levels occur prior to cardiac damage and far before reduced whole heart function. Therefore, claudin-5 may be a useful early therapeutic target for human heart failure. However, the cell types in which claudin-5 is localized in human heart and from which claudin-5 is reduced in heart failure is not known. The recent identification of claudin-5's interaction with ephrin-B1 in mouse hearts has also not been investigated in non-failing or failing human hearts. In this study we collected human left ventricular mid-myocardium histological samples from 7 non-failing hearts and 16 end-stage failing hearts. Immunoblots demonstrate severe reductions of claudin-5 protein in 14 of 16 failing hearts compared to non-failing controls. Claudin-5 was observed to localize to cardiomyocytes, endothelial cells, and a subset of fibroblasts in non-failing human heart sections. In isolated cardiomyocytes, the transmembrane claudin-5 protein localized in longitudinal striations in lateral membranes. In failing heart, both cardiomyocyte and endothelial claudin-5 localization was severely reduced, but claudin-5 remained in fibroblasts. Absence of claudin-5 staining also correlated with the reduction of the endothelial cell marker CD31. Ephrin-B1 localization, but not protein levels, was altered in failing hearts supporting that claudin-5 is required for ephrin-B1 localization. These data support that loss of claudin-5 in cardiomyocytes and endothelial cells is prevalent in human heart failure. Investigating claudin-5/ephrin-B1 protein complexes and gene regulation may lead to novel therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.carpath.2014.10.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4424194PMC
March 2016

Prednisolone attenuates improvement of cardiac and skeletal contractile function and histopathology by lisinopril and spironolactone in the mdx mouse model of Duchenne muscular dystrophy.

PLoS One 2014 13;9(2):e88360. Epub 2014 Feb 13.

Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio, United States of America ; Dorothy M. Davis Heart & Lung Institute, The Ohio State University, Columbus, Ohio, United States of America.

Duchenne muscular dystrophy (DMD) is an inherited disease that causes striated muscle weakness. Recently, we showed therapeutic effects of the combination of lisinopril (L), an angiotensin converting enzyme (ACE) inhibitor, and spironolactone (S), an aldosterone antagonist, in mice lacking dystrophin and haploinsufficient for utrophin (utrn(+/-);mdx, het mice); both cardiac and skeletal muscle function and histology were improved when these mice were treated early with LS. It was unknown to what extent LS treatment is effective in the most commonly used DMD murine model, the mdx mouse. In addition, current standard-of-care treatment for DMD is limited to corticosteroids. Therefore, potentially useful alternative or additive drugs need to be both compared directly to corticosteroids and tested in presence of corticosteroids. We evaluated the effectiveness of this LS combination in the mdx mouse model both compared with corticosteroid treatment (prednisolone, P) or in combination (LSP). We tested the additional combinatorial treatment containing the angiotensin II receptor blocker losartan (T), which is widely used to halt and treat the developing cardiac dysfunction in DMD patients as an alternative to an ACE inhibitor. Peak myocardial strain rate, assessed by magnetic resonance imaging, showed a negative impact of P, whereas in both diaphragm and extensor digitorum longus (EDL) muscle contractile function was not significantly impaired by P. Histologically, P generally increased cardiac damage, estimated by percentage area infiltrated by IgG as well as by collagen staining. In general, groups that only differed in the presence or absence of P (i.e. mdx vs. P, LS vs. LSP, and TS vs. TSP) demonstrated a significant detrimental impact of P on many assessed parameters, with the most profound impact on cardiac pathology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088360PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3923790PMC
October 2014

The force-temperature relationship in healthy and dystrophic mouse diaphragm; implications for translational study design.

Front Physiol 2012 7;3:422. Epub 2012 Nov 7.

Department of Physiology and Cell Biology, The Ohio State University , Columbus, OH, USA.

In the field of muscular dystrophy, striated muscle function is often assessed in vitro in dystrophin-deficient mdx mice in order to test the impact of a potential treatment strategy. Although many past studies have assessed diaphragm contractile function at or near room temperature, the diaphragm performs in vivo at 37°C. To improve translation of bench-top results to possible clinical application, we studied temperature-dependence of contractile performance in wild-type (C57BL/10) and mdx muscle strips at temperatures from 25°C to 37°C. Maximal tetanic force in wild-type muscles was higher at 37°C (198 ± 11 vs. 155 ± 9 mN/mm(2) at 25°C), while the difference between wild-type and mdx was extremely similar: wild-type muscles produced 45.9% and 45.1% more force at 25°C and 37°C respectively. At 37°C twitch contraction kinetics and 50% rise time to tetanic plateau were slower in mdx diaphragm. A fatigue/injury protocol indicated 2-fold fatigue/contraction-induced force deficit in mdx muscles. We conclude that assessment of diaphragm muscle strips can be reliably and reproducibly performed at 37°C.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2012.00422DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491430PMC
November 2012

Cardiomyopathy in the dystrophin/utrophin-deficient mouse model of severe muscular dystrophy is characterized by dysregulation of matrix metalloproteinases.

Neuromuscul Disord 2012 Nov 29;22(11):1006-14. Epub 2012 Jun 29.

Department of Molecular and Cellular Biochemistry, The Ohio State University, College of Medicine, Columbus, OH 43210, United States.

Cardiomyopathy is a significant component in Duchenne muscular dystrophy. Although mdx mice are deficient in dystrophin, they only develop mild indicators of cardiomyopathy before 1year-of-age, making therapeutic investigations using this model lengthy. In contrast, mdx mice also lacking utrophin (utrn(-/-);mdx) show severely reduced cardiac contractile function and histological indicators of cardiomyopathy by 8-10weeks-of-age. Here we demonstrate that utrn(-/-);mdx mice show a similar pattern of cardiac damage to that in dystrophic patients. Matrix metalloproteinases required for ventricular remodeling during the evolution of heart failure are upregulated in utrn(-/-);mdx mice concurrent with the onset of cardiac pathology by 10weeks-of-age. Matrix metalloproteinase activity is further dysregulated due to reduced levels of endogenous tissue inhibitors and co-localizes with fibroblasts and collagen I-containing scars. utrn(-/-);mdx mice are therefore a very useful model for investigating potential cardiac therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nmd.2012.05.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3484217PMC
November 2012

Sustaining cardiac claudin-5 levels prevents functional hallmarks of cardiomyopathy in a muscular dystrophy mouse model.

Mol Ther 2012 Jul 1;20(7):1378-83. Epub 2012 May 1.

Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA.

Identification of new molecular targets in heart failure could ultimately have a substantial positive impact on both the health and financial aspects of treating the large heart failure population. We originally identified reduced levels of the cell junction protein claudin-5 specifically in heart in the dystrophin/utrophin-deficient (Dmd(mdx);Utrn(-/-)) mouse model of muscular dystrophy and cardiomyopathy, which demonstrates physiological hallmarks of heart failure. We then showed that at least 60% of cardiac explant samples from patients with heart failure resulting from diverse etiologies also have reduced claudin-5 levels. These claudin-5 reductions were independent of changes in other cell junction proteins previously linked to heart failure. The goal of this study was to determine whether sustaining claudin-5 levels is sufficient to prevent the onset of histological and functional indicators of heart failure. Here, we show the proof-of-concept rescue experiment in the Dmd(mdx);Utrn(-/-) model, in which claudin-5 reductions were originally identified. Expression of claudin-5 4 weeks after a single administration of recombinant adeno-associated virus (rAAV) containing a claudin-5 expression cassette prevented the onset of physiological hallmarks of cardiomyopathy and improved histological signs of cardiac damage. This experiment demonstrates that claudin-5 may represent a novel treatment target for prevention of heart failure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/mt.2012.81DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3392970PMC
July 2012

Early treatment with lisinopril and spironolactone preserves cardiac and skeletal muscle in Duchenne muscular dystrophy mice.

Circulation 2011 Aug 18;124(5):582-8. Epub 2011 Jul 18.

Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA.

Background: Nearly universal cardiomyopathy in Duchenne muscular dystrophy (DMD) contributes to heart failure and death. Because DMD patients show myocardial fibrosis well before functional impairment, we postulated that earlier treatment using drugs with antifibrotic effect may be beneficial.

Methods And Results: Three groups of 10 utrn(+/-);mdx, or "het" mice, deficient for dystrophin and haploinsufficient for utrophin with skeletal myopathy and cardiomyopathy that closely mimics clinical DMD were studied. One het group received spironolactone and lisinopril starting at 8 weeks of life (het-treated-8); a second received the same starting at 4 weeks of life (het-treated-4), and the third het group was untreated. At 20 weeks, all mice had normal ejection fractions though circumferential strain rate was abnormal (-0.21±0.08) in untreated hets. This improved to -0.40±0.07 in het-treated-8 mice (P=0.003) and further improved to -0.56±0.10 in het-treated-4 mice (P=0.014 for het-treated-4 versus het-treated-8). Treated mice showed less cardiomyocyte damage, with a 44% reduction in intracardiomyocyte serum immunoglobulin G localization in het-treated-8 mice (P<0.0001) and a further 53% reduction in het-treated-4 mice (P=0.0003 versus het-treated-8); matrix metalloproteinases were similarly reduced. Cardiac, limb, and diaphragm function by ex vivo muscle testing remained at 80% of normal with early treatment compared to a decline to 40% of normal skeletal muscle function without treatment.

Conclusions: These findings offer clinically available medications with proven antifibrotic effect as a new therapeutic strategy in DMD. Early initiation greatly attenuated myocardial disease and, for the first time with these drugs, improved skeletal myopathy. Thus, early initiation of such agents warrants further clinical evaluation to maintain ambulatory, respiratory, and cardiac function for patients with DMD and related myopathies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCULATIONAHA.111.031716DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3150227PMC
August 2011

Improvement of cardiac contractile function by peptide-based inhibition of NF-κB in the utrophin/dystrophin-deficient murine model of muscular dystrophy.

J Transl Med 2011 May 17;9:68. Epub 2011 May 17.

Department of Physiology and Cell Biology, Columbus, OH, USA.

Background: Duchenne muscular dystrophy (DMD) is an inherited and progressive disease causing striated muscle deterioration. Patients in their twenties generally die from either respiratory or cardiac failure. In order to improve the lifespan and quality of life of DMD patients, it is important to prevent or reverse the progressive loss of contractile function of the heart. Recent studies by our labs have shown that the peptide NBD (Nemo Binding Domain), targeted at blunting Nuclear Factor κB (NF-κB) signaling, reduces inflammation, enhances myofiber regeneration, and improves contractile deficits in the diaphragm in dystrophin-deficient mdx mice.

Methods: To assess whether cardiac function in addition to diaphragm function can be improved, we investigated physiological and histological parameters of cardiac muscle in mice deficient for both dystrophin and its homolog utrophin (double knockout = dko) mice treated with NBD peptide. These dko mice show classic pathophysiological hallmarks of heart failure, including myocyte degeneration, an impaired force-frequency response and a severely blunted β-adrenergic response. Cardiac contractile function at baseline and frequencies and pre-loads throughout the in vivo range as well as β-adrenergic reserve was measured in isolated cardiac muscle preparations. In addition, we studied histopathological and inflammatory markers in these mice.

Results: At baseline conditions, active force development in cardiac muscles from NBD treated dko mice was more than double that of vehicle-treated dko mice. NBD treatment also significantly improved frequency-dependent behavior of the muscles. The increase in force in NBD-treated dko muscles to β-adrenergic stimulation was robustly restored compared to vehicle-treated mice. However, histological features, including collagen content and inflammatory markers were not significantly different between NBD-treated and vehicle-treated dko mice.

Conclusions: We conclude that NBD can significantly improve cardiac contractile dysfunction in the dko mouse model of DMD and may thus provide a novel therapeutic treatment for heart failure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1479-5876-9-68DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3212940PMC
May 2011

Peptide-based inhibition of NF-κB rescues diaphragm muscle contractile dysfunction in a murine model of Duchenne muscular dystrophy.

Mol Med 2011 May-Jun;17(5-6):508-15. Epub 2011 Jan 20.

Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA.

Deterioration of diaphragm function is one of the prominent factors that contributes to the susceptibility of serious respiratory infections and development of respiratory failure in patients with Duchenne Muscular Dystrophy (DMD). The NF-κB signaling pathway has been implicated as a contributing factor of dystrophic pathology, making it a potential therapeutic target. Previously, we demonstrated that pharmacological inhibition of NF-κB via a small NEMO Binding Domain (NBD) peptide was beneficial for reducing pathological features of mdx mice. Now, we stringently test the effectiveness and clinical potential of NBD by treating mdx mice with various formulations of NBD and use diaphragm function as our primary outcome criteria. We found that administering DMSO-soluble NBD rescued 78% of the contractile deficit between mdx and wild-type (WT) diaphragm. Interestingly, synthesis of a GLP NBD peptide as an acetate salt permitted its solubility in water, but as a negative consequence, also greatly attenuated functional efficacy. However, replacing the acetic acid counterion of the NBD peptide with trifluoroacetic acid retained the peptide's water solubility and significantly restored mdx diaphragm contractile function and improved histopathological indices of disease in both diaphragm and limb muscle. Together, these results support the feasibility of using a mass-produced, water-soluble NBD peptide for clinical use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2119/molmed.2010.00263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3105127PMC
October 2011