REVIEW | doi:10.20944/preprints202203.0265.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: Restrictive Cardiomyopathy; Cardiomyopathy; Cardiovascular Genetics; Desmin; Troponin; Filamin-C
Online: 18 March 2022 (09:05:21 CET)
Restrictive cardiomyopathy is a rare cardiac disease causing severe diastolic dysfunction, ventricular stiffness and dilated atria. In consequence, it induces heart failure often with preserved ejection fraction and is associated with a high mortality. Since a poor clinical prognosis, patients with restrictive cardiomyopathy require frequently heart transplantation. Genetic as well as non-genetic factors contribute to restrictive cardiomyopathy and a significant portion of cases remains of unknown etiology. However, the genetic forms of restrictive cardiomyopathy and the involved molecular pathomechanisms are only partially understood. In this review, we summarize the current knowledge about primary genetic restrictive cardiomyopathy and describe its genetic landscape, which might be of interest for geneticists as well as for cardiologists.
ARTICLE | doi:10.20944/preprints202103.0535.v1
Subject: Medicine & Pharmacology, Allergology Keywords: chemotherapy; cachexia; 5-fluorouracil; skeletal muscle; p38; NF-κB; dystrophin; desmin
Online: 22 March 2021 (13:12:15 CET)
Skeletal myopathy encompasses both atrophy and dysfunction and is a prominent event in cancer and chemotherapy-induced cachexia. Here, we investigate the effects of chemotherapeutic agent, 5-fluorouracil (5FU), on skeletal muscle mass and function, and whether small molecule therapeutic candidate, BGP-15, could be protective against the chemotoxic challenge exerted by 5FU. Additionally, we explore the molecular signature of 5FU treatment. Male Balb/c mice received metronomic tri-weekly intraperitoneal delivery of 5FU (23 mg/kg), with and without BGP-15 (15 mg/kg), 6 times in total over a 15-day treatment period. We demonstrated that neither 5FU, nor 5FU combined with BGP-15, affected body composition indices, skeletal muscle mass or function. Adjuvant BGP-15 treatment did, however, prevent the 5FU-induced phosphorylation of p38 MAPK and p65 NF-κB subunit, signalling pathways involved in cell stress and inflammatory signalling, respectively. This as associated with mitoprotection. 5FU reduced the expression of the key cytoskeletal proteins, desmin and dystrophin, which was not prevented by BGP-15. Combined, these data show that metronomic delivery of 5FU does not elicit physiological consequences to skeletal muscle mass and function but is implicit in priming skeletal muscle with a molecular signature for myopathy. BGP-15 has modest protective efficacy against the molecular changes induced by 5FU.
ARTICLE | doi:10.20944/preprints202208.0152.v1
Subject: Life Sciences, Biochemistry Keywords: Desmin; Myopathy; Cardiomyopathy; Intermediate Filaments; Cytoskeleton; Myofibrillar Myopathy (MFM); Desminopathy; Desmosomes; Protein Aggregation.
Online: 8 August 2022 (10:48:45 CEST)
Desmin is the major intermediate filament protein of all three muscle cell types and connects different cell organelles and multi-protein complexes like the cardiac desmosomes. Several pathogenic mutations in the DES gene cause different skeletal and cardiac myopathies. However, the significance of the majority of DES missense variants is currently unknown since functional data are lacking. To determine whether desmin missense mutations within the highly conserved 1A coil domain cause a filament assembly defect, we generated a set of variants with unknown significance and analyzed systematically the filament assembly in transfected SW13 and H9c2 cells using confocal microscopy. We found that mutations in the N-terminal part of the 1A coil domain affect the filament assembly leading to the cytoplasmic desmin aggregation. In contrast, mutant desmin in the C-terminal part of the 1A coil domain form filamentous structures comparable to wild-type desmin. Our findings suggest that the N-terminal part of the 1A coil domain is a hot spot for pathogenic desmin mutations, which affect the desmin filament assembly leading in consequence to skeletal and/or cardiac myopathies. This study may have relevance for the genetic counselling of patients carrying variants in the 1A coil domain of the DES gene.