Additional stringy sources for electric dipole moments

We show that string models with low energy supersymmetry which accommodate the fermion mass hierarchy generally give nonuniversal soft trilinear couplings (A terms). In conjunction with the apparently large Cabibbo-Kobayashi-Maskawa (CKM) phase, this results in large fermion electric dipole moments (EDMs) even in the absence of CP violating phases in the supersymmetry breaking auxiliary fields and the micro term. Nonobservation of the EDMs therefore implies that strings select special flavor and/or supersymmetry breaking patterns.

Epigenetic analysis of the IFNλ3 gene identifies a novel marker for response to therapy in HCV-infected subjects

Chronic hepatitis C virus (HCV) infection is characterized by high interindividual variability in response to pegylated interferon and ribavirin. A genetic polymorphism on chromosome 19 (rs12979860) upstream of interferon-λ3 (IFNλ3) is associated with a twofold change in sustained virologic response rate after 48 weeks of treatment with pegylated interferon/ribavirin in HCV genotype 1 (GT1) treatment-naïve patients. We conducted epigenetic analysis on the IFNλ3 promoter to investigate whether DNA methylation is associated with response to HCV therapy. DNA samples from HCV GT1-infected subjects receiving an interferon-free paritaprevir-containing combination regimen (N=540) and from HCV-uninfected, healthy controls (N=124) were analysed for IFNλ3 methylation levels. Methylation was strongly associated with rs12979860 allele status whether adjusting for HCV status (r=65.0%, 95% CI: [60.2%, 69.5%]), or not (r=64.4%), both with P<2.2×10-16 . In HCV GT1-infected subjects, C/C genotypes had significantly lower methylation levels relative to C/T or T/T genotypes (P<1×10-14 ), with each T allele resulting in a nine-unit increase in mean methylation level. Methylation levels did not correlate with response in subjects treated for 12 or 24 weeks. However, non-C/C subjects with higher methylation levels were more likely to relapse when treatment duration was 8 weeks. This analysis suggests that methylation status of the IFNλ3 promoter region may be a useful parameter that identifies patients more likely to relapse following HCV therapy; however, continuing therapy for a sufficient duration can overcome this difference. These findings may provide mechanistic insight into the role of IFNλ3 genetic variants in HCV treatment response.

Effects of interleukin-1 receptor antagonist on three types of responses to interleukin-1 in rabbit isolated blood vessels

Interleukin-1 receptor antagonist (IRA) is a secretory product of human monocytes or related cell lines that acts as a pure interleukin-1 (IL-1) antagonist in several bioassays. IRA administration was reportedly a life-saving intervention in rabbits injected with lethal doses of bacterial lipopolysaccharide (LPS). We report the inhibitory effect of IRA on three distinct types of vascular responses to IL-1 in rabbit isolated blood vessels. The rabbit isolated superior mesenteric artery, when precontracted with phenylephrine, relaxed in a sustained manner in less than 30 min following application of recombinant interleukin-1 beta (12-290 pM), and this was a prostaglandin (PG)-dependent and endothelium-independent process. IRA (human recombinant sequence; 0.9-15 nM) behaved as an antagonist of IL-1 alpha or IL-1 beta, based on the surmountability and the concentration dependence, but could only prevent the effect of IL-1, not reverse it. IRA had no direct effect on the preparation and did not influence the acute relaxing effect elicited by substance P or iloprost, a PGI2 mimetic. Exposure to IL-1 beta depressed the response to noradrenaline (NA) in several hours in rabbit aorta rings. The inhibitory effect of IL-1 beta was endothelium and prostaglandin independent, but was prevented by a treatment with NG-nitro-L-arginine (a nitric oxide synthesis inhibitor), cycloheximide, dexamethasone, or IRA. Using the residual NA-induced contraction as a quantification of the IL-1 agonist effect, IRA was a very potent antagonist of IL-1 beta but was not totally surmountable.(ABSTRACT TRUNCATED AT 250 WORDS)

PfMORC protein regulates chromatin accessibility and transcriptional repression in the human malaria parasite, Plasmodium falciparum

The environmental challenges the human malaria parasite, Plasmodium falciparum, faces during its progression into its various lifecycle stages warrant the use of effective and highly regulated access to chromatin for transcriptional regulation. Microrchidia (MORC) proteins have been implicated in DNA compaction and gene silencing across plant and animal kingdoms. Accumulating evidence has shed light on the role MORC protein plays as a transcriptional switch in apicomplexan parasites. In this study, using the CRISPR/Cas9 genome editing tool along with complementary molecular and genomics approaches, we demonstrate that PfMORC not only modulates chromatin structure and heterochromatin formation throughout the parasite erythrocytic cycle, but is also essential to the parasite survival. Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) experiments suggests that PfMORC binds to not only sub-telomeric regions and genes involved in antigenic variation but may also play a role in modulating stage transition. Protein knockdown experiments followed by chromatin conformation capture (Hi-C) studies indicate that downregulation of PfMORC impairs key histone marks and induces the collapse of the parasite heterochromatin structure leading to its death. All together these findings confirm that PfMORC plays a crucial role in chromatin structure and gene regulation, validating this factor as a strong candidate for novel antimalarial strategies.

Quantitative MRI findings indicate diffuse white matter damage in Susac Syndrome

Background

Susac Syndrome (SuS) is an autoimmune endotheliopathy impacting the brain, retina and cochlea that can clinically mimic multiple sclerosis (MS).

Objective

To evaluate non-lesional white matter demyelination changes in SuS compared to MS and healthy controls (HC) using quantitative MRI.

Methods

3T MRI including myelin water imaging and diffusion basis spectrum imaging were acquired for 7 SuS, 10 MS and 10 HC participants. Non-lesional white matter was analyzed in the corpus callosum (CC) and normal appearing white matter (NAWM). Groups were compared using ANCOVA with Tukey correction.

Results

SuS CC myelin water fraction (mean 0.092) was lower than MS(0.11, p = 0.01) and HC(0.11, p = 0.04). Another myelin marker, radial diffusivity, was increased in SuS CC(0.27μm2/ms) compared to HC(0.21μm2/ms, p = 0.008) and MS(0.23μm2/ms, p = 0.05). Fractional anisotropy was lower in SuS CC(0.82) than HC(0.86, p = 0.04). Fiber fraction (reflecting axons) did not differ from HC or MS. In NAWM, radial diffusivity and apparent diffusion coefficient were significantly increased in SuS compared to HC(p < 0.001 for both measures) and MS(p = 0.003, p < 0.001 respectively).

Conclusions

Our results provided evidence of myelin damage in SuS, particularly in the CC, and more extensive microstructural injury in NAWM, supporting the hypothesis that there are widespread microstructural changes in SuS syndrome including diffuse demyelination.

The Toxoplasma gondii F-Box Protein L2 Functions as a Repressor of Stage Specific Gene Expression

Toxoplasma gondii is a foodborne pathogen that can cause severe and life-threatening infections in fetuses and immunocompromised patients. Felids are its only definitive hosts, and a wide range of animals, including humans, serve as intermediate hosts. When the transmissible bradyzoite stage is orally ingested by felids, they transform into merozoites that expand asexually, ultimately generating millions of gametes for the parasite sexual cycle. However, bradyzoites in intermediate hosts differentiate exclusively to disease-causing tachyzoites, which rapidly disseminate throughout the host. Though tachyzoites are well-studied, the molecular mechanisms governing transitioning between developmental stages are poorly understood. Each parasite stage can be distinguished by a characteristic transcriptional signature, with one signature being repressed during the other stages. Switching between stages require substantial changes in the proteome, which is achieved in part by ubiquitination. F-box proteins mediate protein poly-ubiquitination by recruiting substrates to SKP1, Cullin-1, F-Box protein E3 ubiquitin ligase (SCF-E3) complexes. We have identified an F-box protein named Toxoplasma gondii F-Box Protein L2 (TgFBXL2), which localizes to distinct perinucleolar sites. TgFBXL2 is stably engaged in an SCF-E3 complex that is surprisingly also associated with a COP9 signalosome complex that negatively regulates SCF-E3 function. At the cellular level, TgFBXL2-depleted parasites are severely defective in centrosome replication and daughter cell development. Most remarkable, RNAseq data show that TgFBXL2 conditional depletion induces the expression of stage-specific genes including a large cohort of genes necessary for sexual commitment. Together, these data suggest that TgFBXL2 is a latent guardian of stage specific gene expression in Toxoplasma and poised to remove conflicting proteins in response to an unknown trigger of development.

A kalihinol analog disrupts apicoplast function and vesicular trafficking in P. falciparum malaria

We report the discovery of MED6-189, an analog of the kalihinol family of isocyanoterpene natural products that is effective against drug-sensitive and drug-resistant Plasmodium falciparum strains, blocking both asexual replication and sexual differentiation. In vivo studies using a humanized mouse model of malaria confirm strong efficacy of the compound in animals with no apparent hemolytic activity or toxicity. Complementary chemical, molecular, and genomics analyses revealed that MED6-189 targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. Its high potency, excellent therapeutic profile, and distinctive mode of action make MED6-189 an excellent addition to the antimalarial drug pipeline.