Beyond PrPres Type 1/Type 2 Dichotomy in Creutzfeldt-Jakob Disease

Sporadic Creutzfeldt-Jakob disease (sCJD) cases are currently subclassified according to the methionine/valine polymorphism at codon 129 of the PRNP gene and the proteinase K (PK) digested abnormal prion protein (PrPres) identified on Western blotting (type 1 or type 2). These biochemically distinct PrPres types have been considered to represent potential distinct prion strains. However, since cases of CJD show co-occurrence of type 1 and type 2 PrPres in the brain, the basis of this classification system and its relationship to agent strain are under discussion. Different brain areas from 41 sCJD and 12 iatrogenic CJD (iCJD) cases were investigated, using Western blotting for PrPres and two other biochemical assays reflecting the behaviour of the disease-associated form of the prion protein (PrPSc) under variable PK digestion conditions. In 30% of cases, both type 1 and type 2 PrPres were identified. Despite this, the other two biochemical assays found that PrPSc from an individual patient demonstrated uniform biochemical properties. Moreover, in sCJD, four distinct biochemical PrPSc subgroups were identified that correlated with the current sCJD clinico-pathological classification. In iCJD, four similar biochemical clusters were observed, but these did not correlate to any particular PRNP 129 polymorphism or western blot PrPres pattern. The identification of four different PrPSc biochemical subgroups in sCJD and iCJD, irrespective of the PRNP polymorphism at codon 129 and the PrPres isoform provides an alternative biochemical definition of PrPSc diversity and new insight in the perception of Human TSE agents variability

Lung endothelial barrier disruption in Lyl1-deficient mice

Maturation of newly formed vessels is a multistep phenomenon during which functional endothelial barriers are established. Disruption of vessel integrity is an important feature in many physiological and pathological processes. We previously reported that lymphoblastic leukemia-derived sequence 1 (LYL1) is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. In this study, we show that LYL1 is also required during the formation of the mature endothelial barrier in the lungs of adult mice. Specifically, LYL1 knockdown in human endothelial cells downregulated the expression of ARHGAP21 and ARHGAP24, which encode two Rho GTPase-activating proteins, and this was correlated with increased RhoA activity and reorganization of the actin cytoskeleton into stress fibers. Importantly, in lungs of Lyl1-deficient mice, both vascular endothelial (VE)-cadherin and p120-catenin were poorly recruited to endothelial adherens junctions, indicative of defective cell-cell junctions. Consistent with this, higher Evans blue dye extravasation, edema, and leukocyte infiltration in the lung parenchyma of Lyl1-/- mice than in wild-type littermates confirmed that lung vascular permeability is constitutively elevated in Lyl1-/- adult mice. Our data show that LYL1 acts as a stabilizing signal for adherens junction formation by operating upstream of VE-cadherin and of the two GTPases Rap1 and RhoA. As increased vascular permeability is a key feature and a major mechanism of acute respiratory distress syndrome, molecules that regulate LYL1 activity could represent additional tools to modify the endothelial barrier permeability

The first Chinese case of Creutzfeldt-Jakob disease patient with R208H mutation in PRNP

A case of Creutzfeldt-Jakob disease (CJD) with a rare mutation of the prion protein (PrP) gene (PRNP) at codon 208 (R208H), while the codon 129 was a methionine homozygous genotype is reported. The patient initial displayed hand tremor, dizziness and progressive cognitive dysfunction. Subsequently, other symptoms gradually appeared, including cerebellar ataxia and mental disorder. No periodic activity was recorded at electroencephalography (EEG) and 14-3-3 protein in cerebrospinal fluid was negative. Total clinical course was about four months. Retrospective investigation of this family across seven generations did not figure out clear family history. However, genetic analyses revealed six first-degree family members with the R208H allele

Abnormal PrP Properties as Assessed by Western Blot, PK Digestion ELISA and Strain Typing ELISA in 41 French Sporadic CJD Patients and 12 Iatrogenic CJD Patients Originating either from France or the United Kingdom

<p>Sp, Sporadic; DM, iatrogenic cases linked to dura mater grafts; GH, iatrogenic cases linked to growth hormone treatment.</p>a<p>Patients originating from the United Kingdom.</p>b<p>Express the PK concentration for which, when increasing PK concentration, the ELISA PrP^Sc signal reach an arbitrary cut-off value set at 20% of the signal observed with a PK concentration of 50 µg/ml.</p>c<p>Express the ratio of ELISA signal obtained (A/A′) after PrP^sc PK digestion differential PK digestions in a non-perturbing detergent mixture (A), and a denaturing (SDS) detergent mixture (A′).</p

PrPsc PK Resistance and Molecular Strain Variations in sCJD and iCJD Brain Samples.

<p>Each investigated brain sample was initially characterized by WB using antibody Sha31. Symbol patterns represent type 1 in white, type 1+2 in grey and type 2 in black. (A) Results from PK resistance ELISA carried out on three different brain areas (cerebellum, caudate nucleus and temporal cortex) from a MM1 (open circles), a VV1 (open triangles), a VV2 (inverted filled triangle) and a MM2 (filled squares) sCJD patient. Values obtained are expressed as percentage of signal obtained with the lowest PK concentration (50 µg/mL). (B) Results from CEA strain typing ELISA (one symbol per patient—3 to 5 different areas by patients). PrP^Sc signal intensity was measured after PK digestion into two different detergent solutions. Normalized A/A′ ratio was calculated for each sample (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000029#s2" target="_blank">Methods</a> section). MM1 and MV1 had a low ratio indicating an absence of alteration of PrP^sc PK sensitivity linked to the modification detergent digestion conditions. This ratio was higher in MV2, VV2, MV1+2, and VV1+2, while, in the unique VV1 case, an intermediate ratio was observed. In MM2 patients, the huge ratio indicated a strong increase in PK sensitivity by modification of detergent conditions. (C, D) PK resistance assay in three areas from a (C) VV (triangles) or MM (circles) patient and in (D) a MV (triangles) patient harbouring distinct PrP^Sc WB type in their different brain areas. Artificial mixtures of MM2/VV1 or MM1/VV2 samples were prepared. All homogenates were first equilibrated by dilution into negative brain homogenate to obtain an equal PrP^Sc signal in ELISA. (E, F) Mixtures were then tested by Western Blot (200 µg PK digestion—Sha31 anti PrP antibody). (E) Lane 1: MM1 100%; Lane 2: MM1 75%/VV2 25%; Lane 3: MM1 50%/VV2 50%; Lane 4: MM1 25%/VV2 75%; Lane 5: VV2 100%. (F) Lane 1: VV1 100%; Lane 2: VV1 75%/MM2 25%; Lane 3: VV1 50%/MM2 50%; Lane 4: VV1 25%/MM2 75%; Lane 5: MM2 100%. (G, H) Same mixtures were tested in the PK resistance ELISA assay. (G) VV2 100% (filled circles), VV2 75%/MM1 25% (filled triangles), VV2 50%/MM1 50% (filled inverted triangles), VV2 25%/MM1 75% (open triangles), MM1 100% (open circles). (H) MM2 100% (filled circles), MM2 75%/VV1 25% (filled triangles), MM2 50%/VV1 50% (filled inverted triangles), MM2 25%/VV1 75% (open triangles), VV1 100% (open circles).</p