Direct interaction of DNMT inhibitors to PrP suppresses pathogenic process of prion

The conversion of the normal cellular prion protein (PrP) to the misfolded pathogenic scrapie prion protein (PrP) is the biochemical hallmark of prion replication. So far, various chemical compounds that inhibit this conformational conversion have been identified. Here, we report the novel anti-prion activity of SGI-1027 and its meta/meta analogue (M/M), previously known only as potent inhibitors of DNA methyltransferases (DNMTs). These compounds effectively decreased the level of PrP in cultured cells with permanent prion infection, without affecting PrP at the transcriptional or translational levels. Furthermore, SGI-1027 prevented effective prion infection of the cells. In a PrP aggregation assay, both SGI-1027 and M/M blocked the formation of misfolded PrP aggregates, implying that binding of these compounds hinders the PrP conversion process. A series of binding and docking analyses demonstrated that both SGI-1027 and M/M directly interacted with the C-terminal globular domain of PrP, but only SGI-1027 bound to a specific region of PrP with high affinity, which correlates with its potent anti-prion efficacy. Therefore, we report SGI-1027 and related compounds as a novel class of potential anti-prion agents that preferentially function through direct interaction with PrP.

Evaluation of Infective Property of Recombinant Prion Protein Amyloids in Cultured Cells Overexpressing Cellular Prion Protein

Misfolded isoform of prion protein (PrP), termed scrapie PrP (PrP(Sc)), tends to aggregate into various fibril forms. Previously, we reported various conditions that affect aggregation of recombinant PrP into amyloids. Because amyloidogenesis of PrP is closely associated with transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, we investigated infectivity of recombinant PrP amyloids generated in vitro. Using cultured cell lines which overexpress cellular PrP of different species, we measured the level of de novo synthesized PrP(Sc) in cells inoculated with recombinant mouse PrP amyloids. While PrP-overexpressing cells were susceptible to mouse-adapted scrapie prions used as the positive control, demonstrating the species barrier effect, infection with amyloids made of truncated recombinant PrP (PrP[89-230]) failed to form and propagate PrP(Sc) even in the cells that express mouse cellular PrP. This suggests that infectivity of PrP amyloids generated in vitro is different from that of natural prions. Recombinant PrP (89-230) amyloids tested in the current study retain no or a minute level, if any, of prion infectivity.

A Case of Pregnant Woman with 46 , X , del ( X ) ( q 26 ) Turner Karyotype Whose Fetus Shows the Same Karyotype / 대한산부인과학회잡지

Turner syndrome with abnormalities of X chromosome is generally characterized by gonadal dysgenesis causing premature ovarian failure, primary and secondary amenorrhea. Premature ovarian failure is often caused by X chromosome aberrations. It has been shown that gross X chromosome abnormalities such as monosomy X usually result in primary amenorrhea and poor pubertal development, whereas mild X chromosome abnormalities such as partial X deletions usually lead to secondary amenorrhea and fairly good pubertal development. Fertility has been reported in several patients with relatively small Xq deletions before the onset of premature ovarian failure, and the X chromosome abnormality is often inherited by offspring. We describe a 46,X,del(X)(q26) female with normal pregnancy, in whom same karyotype was found in the fetus by amniocentesis. We report this case with brief review of related literatures.