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- Therapeutic strategies based on modified U1 snRNAs and chaperones for Sanfilippo C splicing mutationsPublication . Matos, Liliana; Canals, Isaac; Dridi, Labri; Choi, Yoo; Prata, Maria Joâo; Jordan, Peter; Desviat, Lourdes R.; Perez, Belén; Pshezhetsky, A.V.; Grinberg, Daniel; Alves, Sandra; Vilageliu, LluisaMutations affecting RNA splicing represent more than 20% of the mutant alleles in Sanfilippo syndrome type C, a rare lysosomal storage disorder that causes severe neurodegeneration. Many of these mutations are localized in the conserved donor or acceptor splice sites, while few are found in the nearby nucleotides. METHODS: In this study we tested several therapeutic approaches specifically designed for different splicing mutations depending on how the mutations affect mRNA processing. For three mutations that affect the donor site (c.234 + 1G > A, c.633 + 1G > A and c.1542 + 4dupA), different modified U1 snRNAs recognizing the mutated donor sites, have been developed in an attempt to rescue the normal splicing process. For another mutation that affects an acceptor splice site (c.372-2A > G) and gives rise to a protein lacking four amino acids, a competitive inhibitor of the HGSNAT protein, glucosamine, was tested as a pharmacological chaperone to correct the aberrant folding and to restore the normal trafficking of the protein to the lysosome. RESULTS: Partial correction of c.234 + 1G > A mutation was achieved with a modified U1 snRNA that completely matches the splice donor site suggesting that these molecules may have a therapeutic potential for some splicing mutations. Furthermore, the importance of the splice site sequence context is highlighted as a key factor in the success of this type of therapy. Additionally, glucosamine treatment resulted in an increase in the enzymatic activity, indicating a partial recovery of the correct folding. CONCLUSIONS: We have assayed two therapeutic strategies for different splicing mutations with promising results for the future applications
- Diagnóstico genético da diabetes tipo MODY (Maturity-onset diabetes of the young) em PortugalPublication . Gaspar, G.; Seuanes, F.; Duarte, J.S.; Rodrigues, D.; Moreno, C.; Gouveia, S.; Lobarinhas, G.; Bogalho, A.P.; Agapito, A.; Fonseca, F.; Castro, S.V.; Almeida, B.; Bourbon, M.
- Familial Hypercholesterolemia in PortugalPublication . Bourbon, M.
- An integrative assessment to determine the genotoxic hazard of estuarine sediments: combining cell and whole-organism responsesPublication . Costa, Pedro Manuel; Pinto, Miguel; Vicente, Ana M.; Gonçalves, Cátia; Rodrigo, Ana P.; Louro, Henriqueta; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria JoãoThe application of the Comet assay in environmental monitoring remains challenging in face of the complexity of environmental stressors,e.g.,when dealing with estuarine sediments,that hampers the drawing of cause-effect relationships. Although the in vitro The application of the Comet assay in environmental monitoring remains challenging in face of the complexity of environmental stressors, e.g., when dealing with estuarine sediments, that hampers the drawing of cause-effect relationships. Although the in vitro Comet assay may circumvent confounding factors, its application in environmental risk assessment (ERA) still needs validation. As such, the present work aims at integrating genotoxicity and oxidative DNA damage induced by sediment-bound toxicants in HepG2 cells with oxidative stress-related effects observed in three species collected from an impacted estuary. Distinct patterns were observed in cells exposed to crude mixtures of sediment contaminants from the urban/industrial area comparatively to the ones from the rural/riverine area of the estuary, with respect to oxidative DNA damage and oxidative DNA damage. The extracts obtained with the most polar solvent and the crude extracts caused the most significant oxidative DNA damage in HepG2 cells, as measured by the formamidopyrimidine-DNA glycosylase (FPG)-modified Comet assay. This observation suggests that metals and unknown toxicants more hydrophilic than polycyclic aromatic hydrocarbons may be important causative agents, especially in samples from the rural part of the estuary, where oxidative DNA damage was the most significant. Clams, sole, and cuttlefish responded differentially to environmental agents triggering oxidative stress, albeit yielding results accordant with the oxidative DNA damage observed in HepG2 cells. Overall, the integration of in vivo biomarker responses and Comet assay data in HepG2 cells yielded a comparable pattern, indicating that the in vitro FPG-modified Comet assay may be an effective and complementary line-of-evidence in ERA even in particularly challenging, natural, scenarios such as estuarine environments.