Identification of molecular targets for myotonic dystrophy type 1 using a proteomic approach

• Autor(a) principal: Cruz, Ana Catarina Andrade
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/40929
• topic: Muscular dystrophies; Myotonic dystrophy type 1; Human fibroblasts; Proteomics; Bioinformatic analysis; Signaling pathways

Muscular dystrophies encompass a diverse set of inherited diseases marked by muscle weakness, muscle mass reduction, and occasionally, central nervous system dysfunction. Myotonic dystrophy type 1 (DM1) is an autosomal dominant muscular disorder caused by the expansion of trinucleotides (CTG) in the 3'-untranslated region of the DMPK gene. DM1 patients experience severe symptoms that impact the skeletal muscle system, including myotonia and muscle weakness and atrophy, along with various multisystemic manifestations. Despite extensive research efforts to unravel the molecular mechanisms underlying DM1, there remains a significant knowledge gap, necessitating further investigation to comprehensively understand DM1 pathophysiology. To address this, we conducted a quantitative mass spectrometry analysis of fibroblasts derived from DM1 patients with 1000 (DM_1000) and 2000 CTG repeats (DM1_2000), comparing them to control fibroblasts. Using liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS), we identified 203 differentially expressed proteins (DEPs) in DM1_1000 and 190 DEPs in DM1_2000. Furthermore, a functional bioinformatic analysis of these DEPs revealed that several crucial biological processes, including muscular contraction-relaxation, metabolism of small molecules such as fatty acids and amino acids, glucose metabolism, myogenesis, muscle regeneration/degeneration, skeletal muscle architecture maintenance, and L-arginine biosynthesis are deregulated in DM1. We pinpointed five proteins of particular interest involved in myogenesis, muscle contraction, and muscle bioenergetics: TRPV2, a calcium flux-mediating cationic channel; ASS and ASL, enzymes responsible for L-arginine production; GAA, an enzyme that breaks down glycogen to glucose in lysosomes; and TNK2, a serine/threonine-protein kinase that directly phosphorylates Akt. Additionally, we validated the differences in protein expression of these proteins using immunoblotting and immunocytochemistry techniques. Concluding, our results shed light on potential protein targets and signaling pathways that could be used to develop disease-modifying therapies for DM1. This study offers fresh insights into DM1 pathophysiology and serves as a valuable foundation for future investigations. We recommend further research that includes functional validation of molecular targets, the use of relevant cell models like myoblasts and myotubes, and an assessment of disease severity across different DM1 phenotypes. Additionally, exploring phosphoproteome associated to DMPK protein may provide additional insights into DM1 mechanisms, potentially inspiring innovative treatment strategies.