Project description:Mutations in the gene encoding laminin a2 chain cause congenital muscular dystrophy, MDC1A. In skeletal muscle, laminin a2 chain binds at least two receptor complexes; the dystrophin-glycoprotein complex and integrin a7b1. To gain insight into the molecular mechanisms underlying this disorder, we performed gene expression profiling of laminin a2 chain deficient mouse limb muscle. One of the down-regulated genes encodes a protein called calcium and integrin binding protein 2 (Cib2) whose expression and function is unknown. However, the closely related Cib1 has been reported to bind integrin aIIb and may be involved in outside-in-signaling in platelets. Since Cib2 might be a novel integrin a7b1 binding protein in muscle, we have studied Cib2 expression in the developing and adult mouse. Cib2 mRNA is mainly expressed in the developing central nervous system and in developing and adult skeletal muscle. In skeletal muscle Cib2 colocalizes with integrin a7B subunit at the sarcolemma and at the neuromuscular- and myotendinous junctions. Finally, we demonstrate that Cib2 is a calcium binding protein that interacts with integrin a7Bb1D. Thus, our data suggest a role for Cib2 as a cytoplasmic effector of integrin a7Bb1D signaling in skeletal muscle Experiment Overall Design: Skeletal muscle (all hind limb skeletal muscle) from 4-weeks old laminin alpha 2 chain deficient mice and 4-weeks old wild type mice were isolated individually and RNA were extracted and hybridized on Affiymetrix microarrys. Three biological replicates from each group were analyzed.
Project description:Laminin (merosin) deficient muscular dystrophy in dy/dy mouse diaphragm muscle, 8 weeks old Experiment Overall Design: 4 normal samples; 4 dystrophic samples; Each sample consists of muscle pooled from 3 mice, thus a total of 12 normal and 12 dystrophic mice were studied
Project description:SUMMARY Congenital muscular dystrophy with laminin á2 chain-deficiency (MDC1A) is one of the most severe forms of muscular disease and is characterized by decreased muscle tone at birth, reduced movements and contractures. The genetic basis of MDC1A is well-known, yet the secondary mechanisms ultimately leading to muscle degeneration and subsequent connective tissue infiltration are not fully understood. In order to obtain new insights into the molecular mechanisms underlying MDC1A, we performed a comparative proteomic analysis of affected muscles (diaphragm and gastrocnemius) from laminin á2 chain-deficient dy3K/dy3K mice, using the multidimensional protein identification technology combined with tandem mass tags. Out of the around 700 identified proteins, 113 and 101 proteins, respectively, were differentially expressed in the diseased gastrocnemius and diaphragm muscles compared to normal muscles. A large portion of these proteins are involved in different metabolic processes, bind calcium or are expressed in the extracellular matrix. Our findings suggest that metabolic alterations and calcium dysregulation could be novel mechanisms that underlie MDC1A and might be targets that should be explored for therapy. Also, detailed knowledge of the composition of fibrotic tissue, rich in extracellular matrix proteins, in laminin á2 chain-deficient muscle may help to design future anti-fibrotic treatment.
Project description:In this study, we aim to identify common miRNA signatures in the pathogenesis of different NMD groups (Duchenne Muscular Dystrophy, Megaconial Congenital Muscular Dystrophy (CMD), Ullrich CMD and alpha-dystroglycanopathy) (abbreviated as D, M, U, and A, respectively) each caused by mutations in different genes encoding proteins with distinct roles. For this purpose, we isolated miRNAs from the skeletal muscle tissues of three patients from four disease groups and three control individuals (15 individuals in total) and we performed miRNA microarray method (Affymetrix GeneChip miRNA 4.0 Array). In order to find out differentially expressed miRNAs in patients, we analyzed raw data by two different databases. Differentially expressed miRNAs that were found to be statistically significant by using both the programs (with parameters, fold change ≥2.0 and FDR=0 for MeV-SAM analysis; and p<0.05 for TAC-ANOVA analysis) were identified as the potential miRNA candidates.
Project description:Mutations in the gene encoding laminin a2 chain cause congenital muscular dystrophy, MDC1A. In skeletal muscle, laminin a2 chain binds at least two receptor complexes; the dystrophin-glycoprotein complex and integrin a7b1. To gain insight into the molecular mechanisms underlying this disorder, we performed gene expression profiling of laminin a2 chain deficient mouse limb muscle. One of the down-regulated genes encodes a protein called calcium and integrin binding protein 2 (Cib2) whose expression and function is unknown. However, the closely related Cib1 has been reported to bind integrin aIIb and may be involved in outside-in-signaling in platelets. Since Cib2 might be a novel integrin a7b1 binding protein in muscle, we have studied Cib2 expression in the developing and adult mouse. Cib2 mRNA is mainly expressed in the developing central nervous system and in developing and adult skeletal muscle. In skeletal muscle Cib2 colocalizes with integrin a7B subunit at the sarcolemma and at the neuromuscular- and myotendinous junctions. Finally, we demonstrate that Cib2 is a calcium binding protein that interacts with integrin a7Bb1D. Thus, our data suggest a role for Cib2 as a cytoplasmic effector of integrin a7Bb1D signaling in skeletal muscle Keywords: disese state analysis
Project description:Cancer is considered as a disease of a specific organ, but its effects are felt throughout the body. The systemic effects of cancer can lead to weakness in muscles and heart, which hastens cancer-associated death. miR-486 is a myogenic microRNA and its reduced expression in skeletal muscle is observed in muscular dystrophy. Muscle-specific transgenic expression of miR-486 using muscle creatine kinase promoter (MCK-miR-486) partially rescues skeletal muscle defects in muscular dystrophy animal models. We had previously demonstrated reduced circulating and skeletal muscle levels of miR-486 in several cancer types and lower miR-486 levels correlated with skeletal muscle defects and functional limitations in mammary tumor models. Therefore, skeletal muscle defects induced by cancer could resemble defects observed in various dystrophies, which could be reversed through skeletal muscle expression of miR-486. We performed functional limitations studies and biochemical analysis of skeletal muscles of MMTV-Neu transgenic mice that mimic HER2+ breast cancer and MMTV-PyMT transgenic mice that mimic luminal subtype B breast cancer and these mice crossed to MCK-miR-486 transgenic mice. miR-486 significantly prevented tumor-induced reduction in muscle contraction force, grip strength, and rotarod performance in MMTV-Neu, but not in MMTV-PyMT mice. In MMTV-Neu model, miR-486 reversed several of the cancer-induced changes in skeletal muscle including loss of p53, phospho-AKT, and phospho-laminin alpha 2 (LAMA2) and gain of phosphorylation of the pre-mRNA processing factor hnRNPA0 and the splicing factor SRSF10. LAMA2 is a part of the dystrophin-associated glycoprotein complex, and its loss-of-function mutation is associated with congenital muscular dystrophy. Thus, similar to muscular dystrophy, miR-486 has the potential to reverse skeletal muscle defects and cancer burden in select cancer types.