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