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- Gamble, LD, et al.
(författare)
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A G316A Polymorphism in the Ornithine Decarboxylase Gene Promoter Modulates MYCN-Driven Childhood Neuroblastoma
- 2021
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Ornithine decarboxylase (ODC1), a critical regulatory enzyme in polyamine biosynthesis, is a direct transcriptional target of MYCN, amplification of which is a powerful marker of aggressive neuroblastoma. A single nucleotide polymorphism (SNP), G316A, within the first intron of ODC1, results in genotypes wildtype GG, and variants AG/AA. CRISPR-cas9 technology was used to investigate the effects of AG clones from wildtype MYCN-amplified SK-N-BE(2)-C cells and the effect of the SNP on MYCN binding, and promoter activity was investigated using EMSA and luciferase assays. AG clones exhibited decreased ODC1 expression, growth rates, and histone acetylation and increased sensitivity to ODC1 inhibition. MYCN was a stronger transcriptional regulator of the ODC1 promoter containing the G allele, and preferentially bound the G allele over the A. Two neuroblastoma cohorts were used to investigate the clinical impact of the SNP. In the study cohort, the minor AA genotype was associated with improved survival, while poor prognosis was associated with the GG genotype and AG/GG genotypes in MYCN-amplified and non-amplified patients, respectively. These effects were lost in the GWAS cohort. We have demonstrated that the ODC1 G316A polymorphism has functional significance in neuroblastoma and is subject to allele-specific regulation by the MYCN oncoprotein.
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- Seth-Smith, Helena M. B., et al.
(författare)
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Ongoing evolution of Chlamydia trachomatis lymphogranuloma venereum : exploring the genomic diversity of circulating strains
- 2021
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Ingår i: Microbial Genomics. - : Microbiology Society. - 2057-5858. ; 7:6
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Tidskriftsartikel (refereegranskat)abstract
- Lymphogranuloma venereum (LGV), the invasive infection of the sexually transmissible infection (STI) Chlamydia trachomatis, is caused by strains from the LGV biovar, most commonly represented by ompA- genotypes L2b and L2. We investigated the diversity in LGV samples across an international collection over seven years using typing and genome sequencing. LGV- positive samples (n=321) from eight countries collected between 2011 and 2017 (Spain n=97, Netherlands n=67, Switzerland n=64, Australia n=53, Sweden n=37, Hungary n=31, Czechia n=30, Slovenia n=10) were genotyped for pmpH and ompA variants. All were found to contain the 9 bp insertion in the pmpH gene, previously associated with ompA- genotype L2b. However, analysis of the ompA gene shows ompA- genotype L2b (n=83), ompA- genotype L2 (n=180) and several variants of these (n=52; 12 variant types), as well as other/mixed ompA-genotypes (n=6). To elucidate the genomic diversity, whole genome sequencing (WGS) was performed from selected samples using SureSelect target enrichment, resulting in 42 genomes, covering a diversity of ompA- genotypes and representing most of the countries sampled. A phylogeny of these data clearly shows that these ompA- genotypes derive from an ompA- genotype L2b ancestor, carrying up to eight SNPs per isolate. SNPs within ompA are overrep-resented among genomic changes in these samples, each of which results in an amino acid change in the variable domains of OmpA (major outer membrane protein, MOMP). A reversion to ompA- genotype L2 with the L2b genomic backbone is commonly seen. The wide diversity of ompA- genotypes found in these recent LGV samples indicates that this gene is under immunological selection. Our results suggest that the ompA- genotype L2b genomic backbone is the dominant strain circulating and evolving particularly in men who have sex with men (MSM) populations.
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- Tanrioever, Gaye, et al.
(författare)
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Prominent microglial inclusions in transgenic mouse models of alpha-synucleinopathy that are distinct from neuronal lesions
- 2020
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Ingår i: Acta neuropathologica communications. - : BMC. - 2051-5960. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Alpha-synucleinopathies are a group of progressive neurodegenerative disorders, characterized by intracellular deposits of aggregated alpha-synuclein (alpha S). The clinical heterogeneity of these diseases is thought to be attributed to conformers (or strains) of alpha S but the contribution of inclusions in various cell types is unclear. The aim of the present work was to study alpha S conformers among different transgenic (TG) mouse models of alpha-synucleinopathies. To this end, four different TG mouse models were studied (Prnp-h[A53T]alpha S; Thy1-h[A53T]alpha S; Thy1-h[A30P]alpha S; Thy1-m alpha S) that overexpress human or murine alpha S and differed in their age-of-symptom onset and subsequent disease progression. Postmortem analysis of end-stage brains revealed robust neuronal alpha S pathology as evidenced by accumulation of alpha S serine 129 (p-alpha S) phosphorylation in the brainstem of all four TG mouse lines. Overall appearance of the pathology was similar and only modest differences were observed among additionally affected brain regions. To study alpha S conformers in these mice, we used pentameric formyl thiophene acetic acid (pFTAA), a fluorescent dye with amyloid conformation-dependent spectral properties. Unexpectedly, besides the neuronal alpha S pathology, we also found abundant pFTAA-positive inclusions in microglia of all four TG mouse lines. These microglial inclusions were also positive for Thioflavin S and showed immunoreactivity with antibodies recognizing the N-terminus of alpha S, but were largely p-alpha S-negative. In all four lines, spectral pFTAA analysis revealed conformational differences between microglia and neuronal inclusions but not among the different mouse models. Concomitant with neuronal lesions, microglial inclusions were already present at presymptomatic stages and could also be induced by seeded alpha S aggregation. Although nature and significance of microglial inclusions for human alpha-synucleinopathies remain to be clarified, the previously overlooked abundance of microglial inclusions in TG mouse models of alpha-synucleinopathy bears importance for mechanistic and preclinical-translational studies.
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