Browsing by Issue Date, starting with "2023-11-17"
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- Efficacy of the Vaccine Candidate Based on the P0 Peptide against Dermacentor nitens and Ixodes ricinus TicksPublication . Rodríguez Mallon, A.; Encinosa Guzmán, P.E.; Bello, Y.; Domingos, A.; Antunes, S.; Kopacek, P.; Santos, A.S.; Velez, R.; Perner, J.; Ledesma Bravo, F.L.; Frantova, H.; Erhart, J.; Rodríguez, R.; Fuentes, A.; Diago, D.; Joglar, M.; Méndez, L.; Estrada, M.P.The control of ticks through vaccination offers a sustainable alternative to the use of chemicals that cause contamination and the selection of resistant tick strains. However, only a limited number of anti-tick vaccines have reached commercial realization. In this sense, an antigen effective against different tick species is a desirable target for developing such vaccines. A peptide derived from the tick P0 protein (pP0) conjugated to a carrier protein has been demonstrated to be effective against the Rhipicephalus microplus, Rhipicephalus sanguineus, and Amblyomma mixtum tick species. The aim of this work was to assess the efficacy of this peptide when conjugated to the Bm86 protein against Dermacentor nitens and Ixodes ricinus ticks. An RNAi experiment using P0 dsRNA from I. ricinus showed a dramatic reduction in the feeding of injected female ticks on guinea pigs. In the follow-up vaccination experiments, rabbits were immunized with the pP0-Bm86 conjugate and challenged simultaneously with larvae, nymphs, and the adults of I. ricinus ticks. In the same way, horses were immunized with the pP0-Bm86 conjugate and challenged with D. nitens larva. The pP0-Bm86 conjugate showed efficacies of 63% and 55% against I. ricinus and D. nitens ticks, respectively. These results, combined with previous reports of efficacy for this conjugate, show the promising potential for its development as a broad-spectrum anti-tick vaccine.
- Effects of TiO2 Nanoparticles on the Genome-Wide Methylation of Human Epithelial Intestinal CellsPublication . Valente, Ana; Vieira, Luís; Silva, Catarina; Louro, Henriqueta; Silva, Maria João; Ventura, CéliaIntroduction: Titanium dioxide nanoparticles (TiO2NP) have multiple applications in industry (e.g., engineering, cosmetics, food additives), and biomedicine (e.g., targeted drug delivery and biosensing). Food-grade TiO2 (E171) is applied as a food additive to whiten and improve the opacity of food products, while also having the ability to enhance its flavour. In 2021, EU member states banned E171 from all food products, since there is doubts about its genotoxicity. Nevertheless, the ingestion of TiO2NPs may still occur through to other sources, such as contaminated food or water, consumer products (e.g., toothpaste and lipstick) or pharmaceutics. To date, there is some in vitro evidence that TiO2NP may induce changes in DNA methylation. However, very few studies were performed, and none used genome-wide approaches to identify possible differentially methylated genes induced by TiO2NP exposure, and its impact on molecular pathways. Methodology: Caco-2 epithelial intestinal cells were exposed to 14 μg/ml of anatase, rutile or brookite phase TiO2NP for 24h. Genomic DNA was extracted from exposed and non-exposed cells. DNA libraries were generated using the Premium Reduced Representative Bisulfite Sequencing (RRBS) kit (Diagenode) and sequenced on the NextSeq 550 system (Illumina) using 100 bp paired reads. The Galaxy platform was used for read treatment and mapping, methylation calling and assessing of differentially methylated regions between exposed and non-exposed cells. Pathway analysis was performed using Reactome, and gene ontology analysis with the ClueGO plugin in Cytoscape. Results: Significant differential methylation (p ≤ 0.05) of 92 genes (21 hyper- and 71 hypo-methylated), 70 genes (12 hyper- and 58 hypo-methylated) and 88 genes (21 hyper- and 67 hypo-methylated) was observed for the anatase, rutile and brookite phase TiO2NP, respectively. Functional pathway analysis of these methylation changes identified several relevant cellular pathways that may be altered by exposure, such as G alpha signalling events, being some associated to colon cancer. Conclusions: All types of TiO2NP induce changes in genome methylation of intestinal cells, which may affect cell proliferation, differentiation and survival. Moreover, although some dysfunctional pathways are shared between the three TiO2NP, many are type-specific, suggesting different molecular mechanisms of action for each TiO2NP.
- The complexity of identification of pathogenic variantsPublication . Fino, Joana; David, DezsoIntroduction: Natural occurring genomic variant, from single nucleotide to balanced, unbalanced and complex rearrangements, spanning large chromosomal regions, has been reported to cause human pathologies. As such, we present cases with neurodevelopmental disorder, infertility, and recurrent miscarriage, which reflect the complexity of the identification of pathogenic variants, considering the variation spectrum, the underlying pathogenic mechanisms, and the heterogeneous clinical presentations. Methods: Long and small insert genomic sequencing (GS) was applied to four cases. Variants were identified from GS data mapped against the reference human genome and confirmed through Sanger sequencing. Results were interpreted using SVInterpreter, Exomiser, genotype-phenotype correlation and convergent genomic data analysis. Results: Although the first case is a carrier of a t(17;19)(p13.1;p13.3)mat, disrupting GSG1L2, and of a presumably paternally inherited dup(2)(q14.3q21.1), encompassing the autosomal dominant (AD) phenotype-associated PROC and HS6ST1 genes, the identified novel frameshift c.4442del, p.(Gly1481Valfs*21) variant of CHD4, was considered the disease-causing variant, since the proband’s phenotype fits the CHD4-associated Sifrim-Hitz-Weiss syndrome (Da Silva et al., 2022). Cases 2 and 3 were both reported with infertility, and carriers of t(5;9)(q31.3;p13) and t(4;21)(p14;q21.3), respectively. Our study revealed that the phenotype most plausibly resulted from a chromosomal position effect over YIPF5 and SPATC1L. The last case, presented intellectual disability and recurrent miscarriage, associated to t(7;22)(p13;q13.1). The 7p13 breakpoint disrupts the brain specific CAMK2B, causing AD mental retardation 54 (OMIM #617799), whereas increased meiotic segregation of der(22), during gametogenesis, most likely explain the reported miscarriage (David et al., 2023). Conclusions: These cases highlight the intricacy of pathogenic mechanisms leading to human disorders, the necessity for identification and evaluation of the “full” spectrum of genomic and genetic variants, of comparative reverse phenotyping, including patients with pathogenic variants affecting the same genes. Finally, highlight the need of introducing a more precise genomic medicine in clinical practice. This research was supported by FCT—Fundação para a Ciência e a Tecnologia, Research Grant HMSP-ICT/0016/2013 of the Harvard Medical School—Portugal Program.