Novel molecular insights into neuroinflammatory and myogenic pathways: lncRNAs as neuromodulator in Parkinson’s disease and TNPO3’s role in LGMD D2 pathogenesis

The characterization of human genes with unknown functions through functional genomics approaches is fundamental to shed light on the molecular mechanisms underlying both basic biological functions and pathological events. This thesis focuses, in Part I, on the study and characterization of complex human genes, particularly long non-coding RNAs (lncRNAs), their role in the central nervous system (CNS) physiology, and their involvement in neurodegenerative processes, such as Parkinson's disease (PD). Previous transcriptomic analyses of post-mortem brain samples from PD patients revealed up-regulation of LINC00520 and down-regulation of LINC00641, suggesting a potential involvement of these lncRNAs in disease mechanisms. In vitro models showed that LINC00520 modulation affects oxidative stress and inflammatory responses, underscoring its relevance in neuronal homeostasis, especially given the high lncRNAs transcript levels during neuronal differentiation. In the zebrafish animal model, the characterization of a putative orthologous lncRNA of human LINC00520 is ongoing, to establish an in vivo model to analyse the complexity of lncRNA regulatory mechanisms in the CNS. Part II focuses on establishing an in vivo zebrafish model of Limb-Girdle Muscular Dystrophy type D2 (LGMD D2) to better understand the disease's pathogenesis and to investigate the role of TNPO3 in muscle development, since a heterozygous mutation in the terminal codon of TNPO3 gene has been described as causative of LGMD D2. Microinjections of mRNAs encoding either wild-type or mutated forms of human TNPO3 were performed in zebrafish embryos to study their effects on myogenesis. Gene expression analyses showed altered profile of Myogenic Regulatory Factors (MRFs) and muscle-specific proteins, while phenotypic studies revealed abnormal muscle fibers organization in zebrafish embryos expressing mutated TNPO3 mRNA. These findings demonstrate the effectiveness of this approach in establishing a zebrafish model of LGMD D2 and highlight the role of TNPO3 in muscle development and differentiation as a potential pathogenetic mechanism underlying LGMD D2.