Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous histopathologic studies of sporadic inclusion body myositis (sIBM) identified sarcoplasmic aggregation and myonuclear depletion of the predominantly nuclear heterogeneous nuclear ribonucleoprotein (hnRNP) TDP-43 in sIBM myofibers. Here, we examined sIBM muscle for abnormalities in two other hnRNPs hnRNPA1 and hnRNPA2B1, mutations in which cause multisystem proteinopathy associated with rimmed-vacuolar myopathies. Muscle biopsy specimens from 13 patients with sIBM and 13 patients without sIBM (dermatomyositis N=3, polymyositis N=3, muscular dystrophy N=3, motor neuron disease N=2, non-neuromuscular disease N=2) underwent immunohistochemistry for hnRNPA1, hnRNPA2B1, and TDP-43. Muscle transcriptional microarray data from 27 patients with sIBM and 12 patients without neuromuscular disease was analyzed. Depletion of hnRNPA1 and hnRNPA2B1 was present in 15% and 7% of sIBM myonuclei, respectively, compared with 1% and 0% of myonuclei in non-sIBM muscle. Sarcoplasmic aggregates of hnRNPA1 and hnRNPA2B1 distinct from TDP-43 aggregates were also found in sIBM. hnRNPA1 and hnRNPA2B1, as well as other hnRNPs, gene expression was unaltered in sIBM compared to normal muscle. Along with TDP-43, other hnRNPs, including hnRNPA1 and hnRNPA2B1, are depleted from sIBM myonuclei at the protein but not transcript level. The depletion of multiple hnRNPs from sIBM myonuclei together with their sarcoplasmic aggregation suggests that one aspect of sIBM pathophysiology may involve abnormal RNA metabolism that includes hyperassembly of ribonucleoprotein granules mediated by prion-like domains in hnRNPs, evolving into pathological aggregates.
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PMID:Abnormal distribution of heterogeneous nuclear ribonucleoproteins in sporadic inclusion body myositis. 2485 66

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by loss of motor neurons and appearance of skein-like inclusions. The inclusions are composed of trans-activation response (TAR) DNA-binding protein 43 (TDP-43), a member of the heterogeneous nuclear ribonucleoprotein (hnRNP) family. hnRNPA1 and hnRNPA2/B1 are hnRNPs that interact with the C-terminus of TDP-43. Using immunohistochemistry, we investigated the association between TDP-43 and hnRNPA1 in ALS spinal motor neurons. We examined spinal cords of seven ALS cases and six muscular dystrophy cases (used as controls) for the presence of TDP-43 and hnRNPA1 protein. In the control cases, hnRNPA1 immunoreactivity in motor neurons was intense in the nucleus and weak in the cytoplasm where it showed a fine granular appearance. In the ALS cases, hnRNPA1 immunoreactivity in motor neurons was reduced in the nuclei of neurons with skein-like inclusions but was not detected in the skein-like inclusions. The marked loss of hnRNPA1 in motor neurons with concomitant cytoplasmic aggregation of TDP-43 may represent a severe disturbance of mRNA processing, suggesting a key role in progressive neuronal death in ALS.
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PMID:Loss of hnRNPA1 in ALS spinal cord motor neurons with TDP-43-positive inclusions. 2533 72

A hallmark of many neuromuscular diseases including Alzheimer disease, inclusion body myositis, amyotrophic lateral sclerosis, frontotemporal lobar dementia, and ocular pharyngeal muscular dystrophy is large cytoplasmic aggregates containing the RNA-binding protein, TDP-43. Despite acceptance that cytoplasmic TDP-43 aggregation is pathological, cytoplasmic TDP-43 assemblies form in healthy regenerating muscle. These recently discovered ribonucleoprotein assemblies, termed myo-granules, form in healthy muscle following injury and are readily cleared as the myofibers mature. The formation and dissolution of myo-granules during normal muscle regeneration suggests that these amyloid-like oligomers may be functional and that perturbations in myo-granule kinetics or composition may promote pathological aggregation.
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PMID:Myo-granules Connect Physiology and Pathophysiology. 3046 63