calpain and Myositis

Topics: Animals; Calpain; Child; Diagnosis, Differential; Eosinophilia; Humans; Muscle Proteins; Muscular Diseases; Mutation; Myositis

Exercise-induced muscle damage is a well documented phenomenon that often follows unaccustomed and sustained metabolically demanding activities. This is a well researched, but poorly understood area, including the actual mechanisms involved in the muscle damage and repair cycle. An integrated model of muscle damage has been proposed by Armstrong and is generally accepted. A more recent aspect of exercise-induced muscle damage to be investigated is the potential of estrogen to have a protective effect against skeletal muscle damage. Estrogen has been demonstrated to have a potent antioxidant capacity that plays a protective role in cardiac muscle, but whether this antioxidant capacity has the ability to protect skeletal muscle is not fully understood. In both human and rat studies, females have been shown to have lower creatine kinase (CK) activity following both eccentric and sustained exercise compared with males. As CK is often used as an indirect marker of muscle damage, it has been suggested that female muscle may sustain less damage. However, these findings may be more indicative of the membrane stabilising effect of estrogen as some studies have shown no histological differences in male and female muscle following a damaging protocol. More recently, investigations into the potential effect of estrogen on muscle damage have explored the possible role that estrogen may play in the inflammatory response following muscle damage. In light of these studies, it may be suggested that if estrogen inhibits the vital inflammatory response process associated with the muscle damage and repair cycle, it has a negative role in restoring normal muscle function after muscle damage has occurred. This review is presented in two sections: firstly, the processes involved in the muscle damage and repair cycle are reviewed; and secondly, the possible effects that estrogen has upon these processes and muscle damage in general is discussed. The muscle damage and repair cycle is presented within a model, with particular emphasis on areas that are important to understanding the potential effect that estrogen has upon these processes.

Topics: Calcium; Calpain; Creatine Kinase; Cytokines; Estrogens; Exercise; Homeostasis; Humans; Muscle, Skeletal; Myositis; Pain; Perception

Limb girdle muscular dystrophies (LGMDs) are a group of clinically heterogeneous genetic diseases characterized by progressive weakness and atrophy of scapular and pelvic muscles, with either a dominant or recessive autosomic mode of inheritance. The first symptoms of the disorder appear during the first 20 years of life and progresses gradually, and a walking disability develops 10-20 years later. The gene responsible for LGMD2A has been identified and encodes calpain 3, a protease expressed mainly in skeletal muscle. Apoptotic myonuclei were recently detected in muscular biopsy specimens of LGMD2A patients, and apoptosis was found to be correlated with altered subcellular distribution of inhibitory protein kappaBalpha (IkappaBalpha) and nuclear factor kappaB (NF-kappaB), resulting in sarcoplasmic sequestration of NF-kappaB. Calpain 3 dependent IkappaBalpha degradation was reconstituted in vitro, supporting a possible in vivo sequence of events leading from calpain 3 deficiency to IkappaBkappa accumulation, prevention of nuclear translocation of NF-kappaB, and ultimately apoptosis. Therefore calpain 3, present in healthy muscle as sarcoplasmic and nuclear forms, may control IkappaBalpha turnover and indirectly regulate NF-kappaB dependent expression of survival genes. Recent data reported from a new model of LGMD2A in mice and from other muscular disorders strengthen understanding of the molecular links between calpain 3 and the Ikappaalpha/NF-kappaB pathway. Finally, in light of the lack of apoptosis observed in inflammatory myopathies, a unifying model for the control of cell survival in muscle is proposed and discussed

Topics: Animals; Apoptosis; Calpain; Cell Survival; DNA-Binding Proteins; Humans; I-kappa B Proteins; Isoenzymes; Models, Biological; Muscle Proteins; Muscle, Skeletal; Muscular Dystrophies; Myositis; NF-kappa B; NF-KappaB Inhibitor alpha

Topics: Adult; Calpain; Child; Child, Preschool; Eosinophilia; Eosinophils; Female; Humans; Male; Muscle Proteins; Muscle, Skeletal; Muscular Dystrophies, Limb-Girdle; Mutation; Myositis

In idiopathic inflammatory myopathies (IIMs), extracellular inflammatory stimulation is considered to induce secondary intracellular inflammatory changes including expression of major histocompatibility complex class-I (MHC-I) and to produce a self-sustaining loop of inflammation. We hypothesize that activation of calpain, a Ca(2+) -sensitive protease, bridges between these extracellular inflammatory stress and intracellular secondary inflammatory changes in muscle cells. In this study, we demonstrated that treatment of rat L6 myoblast cells with interferon-γ (IFN-γ) caused expression of MHC-I and inflammation-related transcription factors (phosphorylated-extracellular signal-regulated kinase 1/2 and nuclear factor-κB). We also demonstrated that treatment with tumor necrosis factor-α (TNF-α) induced apoptotic changes and activation of calpain and cyclooxygenase-2. Furthermore, we found that posttreatment with calpeptin attenuated the intracellular changes induced by IFN-γ or TNF-α. Our results indicate that calpain inhibition attenuates apoptosis and secondary inflammatory changes induced by extracellular inflammatory stimulation in the muscle cells. These results suggest calpain as a potential therapeutic target for treatment of IIMs.

Topics: Animals; Apoptosis; Blotting, Western; Calpain; Cell Line; Cyclooxygenase 2; Cysteine Proteinase Inhibitors; Dipeptides; Histocompatibility Antigens Class I; Inflammation; Interferon-gamma; Myoblasts; Myositis; NF-kappa B; Rats; Signal Transduction; Transcription, Genetic; Tumor Necrosis Factor-alpha

An 11-year-old girl with a calpain-3 gene (CAPN-3) mutation and eosinophilic myositis on muscle biopsy had high serum CK levels and eosinophil counts which showed spontaneous fluctuations. After commencement of immunosuppressive therapy reciprocal changes occurred in response to alterations in doses of the medications. Subacutely evolving and spreading muscle weakness developed during tapering of the immunosuppressive medications. These observations suggest that either the occurrence of eosinophilic myositis or the withdrawal of the immunosuppressive treatment may have accelerated the clinical course of the calpainopathy in this case. The positive effect of immunosuppressive therapy might have implications for the management of calpainopathy with an inflammatory component.

Topics: Azathioprine; Calpain; Child; Creatine Kinase; Disease Progression; Dose-Response Relationship, Drug; Drug Therapy, Combination; Eosinophilia-Myalgia Syndrome; Eosinophils; Female; Genetic Predisposition to Disease; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Leukocyte Count; Methylphenazonium Methosulfate; Muscle Proteins; Muscle Weakness; Muscle, Skeletal; Muscular Dystrophies, Limb-Girdle; Myositis; Prednisolone; Treatment Outcome

Mutations in the gene encoding calpain-3 (CAPN3) cause autosomal recessive limb-girdle muscular dystrophy type 2A (LGMD2A) and idiopathic eosinophilic myositis. Accurate diagnosis and genetic counselling are based on the identification of disease-causing mutations on both alleles of CAPN3 in the patients. In the present study, we used transcriptional analysis as a complementary approach for patients suspected of being affected with LGMD2A, in whom initial denaturing high-performance liquid chromatography genomic mutation screening evidenced no or only one CAPN3 mutation obviously considered as disease causing. This allowed to identify and characterize cDNA deletions. Further genomic analysis allowed to determine the origin of these deletions, either as splicing defects caused by intronic mutations or as an internal multi-exonic deletion. In particular, we report two novel CAPN3 mutations (c.1745 + 4_1745 + 7delAGTG in IVS13 and c.2185-16A>G in IVS20) and a recurrent large-sized genomic deletion including exons 2-8 for which genomic breakpoints have been characterized. In addition, our results indicate nonsense-mediated messenger RNA decay as a mechanism for under-expression of CAPN3 associated to some specific variations.

Topics: Adolescent; Adult; Aged; Base Sequence; Calpain; DNA Primers; Eosinophilia; Female; Humans; Male; Middle Aged; Muscle Proteins; Muscular Dystrophies, Limb-Girdle; Mutation; Myositis; RNA Splicing; RNA Stability; RNA, Messenger; Sequence Deletion; Transcription, Genetic

Eosinophilic myositis (EM) constitutes a rare pathological entity characterized by eosinophilic infiltration of skeletal muscles, usually associated with parasite infections, systemic disorders, or the intake of drugs or L-tryptophan. The exclusion of such causes defines the spectrum of idiopathic EM. Based on a protein analysis performed in one affected patient, we identified the gene encoding calpain-3, CAPN3, as a candidate for a subset of idiopathic EM.. We screened CAPN3 for mutations using DHPLC and direct sequencing in six unrelated patients, recruited for EM diagnosed after histological examination of muscle biopsy samples, without any identified causative factor.. We identified CAPN3 mutations in the six unrelated patients originally diagnosed with idiopathic EM.. Mutations in CAPN3 can cause EM. Thus, a subset of idiopathic EM is genetically determined, with an autosomal recessive mode of inheritance. Patients presented with a triad that appears to be indicative of CAPN3 mutations: (1) EM in the first decade, (2) elevated serum creatine phosphokinase levels (isolated or with little corresponding weakness), and (3) inconstant peripheral hypereosinophilia. However, that EM represents a distinct phenotype associated to CAPN3 mutations or, rather, an early histopathological picture of LGMD2A must be further evaluated. Our findings should be of interest toward further investigating the role of calpain-3 in skeletal muscle. Furthermore, patients with idiopathic EM should undergo calpain-3 protein analysis and be considered for subsequent molecular analysis of the CAPN3 gene.

Topics: Blotting, Western; Calpain; Child; Child, Preschool; Creatine Kinase; Eosinophilia; Female; Genetic Predisposition to Disease; Humans; Immunohistochemistry; Male; Muscle Proteins; Mutation; Myositis; Polymerase Chain Reaction

Chronic inflammation in tibialis anterior muscles of mdx mice was produced by a single injection of a recombinant adenovirus vector (AV) expressing an immunogenic beta-galactosidase (beta-gal). In regions of intense beta-gal staining, mononuclear infiltrates abounded, and muscle fibers showed strong extrasynaptic utrophin immunostaining, restoration of dystrophin-associated protein complex, and a marked reduction of the prevalence of centronucleation. Immunoblot analysis confirmed an increase of endogenous utrophin without an increase of the mRNA of the major muscle isoform utrA. Significantly better maximal tetanic force values were demonstrated in the inflammatory versus control mdx muscles. The resistance to lengthening contraction- induced damage was also significantly increased in the former. In muscles of mice lacking TNF-alpha gene, AV vector did not induce inflammation and extrajunctional utrophin increase did not occur. In the inflammatory mdx muscles, proteolytic activity of calcium-activated calpain was reduced, and in mdx myotubes in vitro, incubation with NO donors also reduced calpain-mediated utrophin proteolysis. Since utrophin was shown to be a natural substrate of calpain and known inhibitors of calpain in cultured mdx myotubes increased utrophin levels, the above results were consistent with the following conclusions: (1) extrasynaptic utrophin increase is mainly responsible for the antidystrophic effect; (2) extrasynaptic utrophin increase is a result of posttranscriptional mechanism(s) related to proinflammatory factors; and (3) reduction of endogenous muscle calpain activity by inflammatory cytokines has an important role in the stabilization and increase of the extrasynaptic utrophin.

Topics: Adenoviridae; Animals; Animals, Newborn; beta-Galactosidase; Calcium; Calpain; Cells, Cultured; Chronic Disease; Cytokines; Male; Mice; Mice, Inbred mdx; Mice, Knockout; Muscle Fibers, Skeletal; Muscle, Skeletal; Myositis; Nitric Oxide Donors; Protein Processing, Post-Translational; Sarcolemma; Synapses; Utrophin

To clarify the involvement of calpains in sarcolemmal remodeling, we examined the expression of calpains and their substrate, alpha-fodrin, in various disorders of muscle. Although immunohistological reactions for alpha-fodrin and calpains were weak in normal control muscles, intense immunoreactivity for alpha-fodrin at the sarcolemma and for calpains throughout the cytoplasm were detected in small muscle fibers from patients with inflammatory myositis (IM), rhabdomyolysis (Rhab), and Duchenne muscular dystrophy (DMD). Most of the calpain-alpha-fodrin double-positive muscle fibers in IM and Rhab also expressed the developmental form of myosin heavy chain. The sarcolemma of these small muscle fibers reacted with an antibody that specifically recognizes the 150-kDa fragments of alpha-fodrin (SBDP 150s) cleaved by calpain, but not caspase 3. Western blot analysis confirmed these results. These observations indicate that calpain is activated and reacts with alpha-fodrin as a substrate at the sarcolemma, and plays a key role in modulating sarcolemmal proteins to adapt to the specific conditions in each myopathy.

Topics: Adult; Aged; Antibody Specificity; Calpain; Carrier Proteins; Child; Child, Preschool; Female; Humans; Immunohistochemistry; Male; Microfilament Proteins; Middle Aged; Muscle, Skeletal; Muscular Diseases; Muscular Dystrophy, Duchenne; Myosin Heavy Chains; Myositis; Peptide Fragments; Rhabdomyolysis; Sarcolemma

Human tibial muscular dystrophy and limb-girdle muscular dystrophy 2J are caused by mutations in the giant sarcomeric protein titin (TTN) adjacent to a binding site for the muscle-specific protease calpain 3 (CAPN3). Muscular dystrophy with myositis (mdm) is a recessive mouse mutation with severe and progressive muscular degeneration caused by a deletion in the N2A domain of titin (TTN-N2ADelta83), disrupting a putative binding site for CAPN3. To determine whether the muscular dystrophy in mutant mdm mice is caused by misregulation of CAPN3 activity, genetic crosses with CAPN3 overexpressing transgenic (C3Tg) and CAPN3 knockout (C3KO) mice were generated. Here, we report that overexpression of CAPN3 exacerbates the mdm disease, leading to a shorter life span and more severe muscular dystrophy. However, in a direct genetic test of CAPN3's role as a mediator of mdm pathology, C3KO;mdm double mutant mice showed no change in the progression or severity of disease indicating that aberrant CAPN3 activity is not a primary mechanism in this disease. To determine whether we could detect a functional deficit in titin in a non-disease state, we examined the treadmill locomotion of heterozygous +/mdm mice and detected a significant increase in stride time with a concomitant increase in stance time. Interestingly, these altered gait parameters were completely corrected by CAPN3 overexpression in transgenic C3Tg;+/mdm mice, supporting a CAPN3-dependent role for the N2A domain of TTN in the dynamics of muscle contraction.

Topics: Animals; Binding Sites; Calpain; Connectin; Crosses, Genetic; Exercise Test; Locomotion; Mice; Mice, Knockout; Mice, Transgenic; Muscle Contraction; Muscle Proteins; Muscle, Skeletal; Muscular Dystrophies; Mutation; Myositis; Protein Kinases; Protein Structure, Tertiary; Transcriptional Activation

Muscular dystrophy with myositis (mdm) is a recessive mouse mutation that causes severe and progressive muscular degeneration. Here we report the identification of the mdm mutation as a complex rearrangement that includes a deletion and a LINE insertion in the titin (Ttn) gene. Mutant allele-specific splicing results in the deletion of 83 amino acids from the N2A region of TTN, a domain thought to bind calpain-3 (CAPN3) the product of the human limb-girdle muscular dystrophy type 2A (LGMD2A) gene. The Ttn(mdm) mutant mouse may serve as a model for human tibial muscular dystrophy, which maps to the TTN locus at 2q31 and shows a secondary reduction of CAPN3 similar to that observed in mdm skeletal muscle. This is the first demonstration that a mutation in Ttn is associated with muscular dystrophy and provides a novel animal model to test for functional interactions between TTN and CAPN3.

Topics: Animals; Calpain; Chromosome Mapping; Cloning, Molecular; Connectin; Gene Deletion; Ligands; Mice; Mice, Inbred C57BL; Muscle Proteins; Muscle, Skeletal; Muscular Dystrophy, Animal; Mutagenesis, Insertional; Myositis; Peptide Fragments; Protein Binding; Protein Kinases; Protein Structure, Tertiary