Designer high-density lipoprotein particles enhance endothelial barrier function and suppress inflammation.

High-density lipoprotein (HDL) nanoparticles promote endothelial cell (EC) function and suppress inflammation, but their utility in treating EC dysfunction has not been fully explored. Here, we describe a fusion protein named ApoA1-ApoM (A1M) consisting of apolipoprotein A1 (ApoA1), the principal structural protein of HDL that forms lipid nanoparticles, and ApoM, a chaperone for the bioactive lipid sphingosine 1-phosphate (S1P). A1M forms HDL-like particles, binds to S1P, and is signaling competent.

Signal Transduction and Gene Regulation in the Endothelium.

Extracellular signals act on G-protein-coupled receptors (GPCRs) to regulate homeostasis and adapt to stress. This involves rapid intracellular post-translational responses and long-lasting gene-expression changes that ultimately determine cellular phenotype and fate changes. The lipid mediator sphingosine 1-phosphate (S1P) and its receptors (S1PRs) are examples of well-studied GPCR signaling axis essential for vascular development, homeostasis, and diseases.

Sphingosine 1-phosphate-regulated transcriptomes in heterogenous arterial and lymphatic endothelium of the aorta.

Despite the medical importance of G protein-coupled receptors (GPCRs), in vivo cellular heterogeneity of GPCR signaling and downstream transcriptional responses are not understood. We report the comprehensive characterization of transcriptomes (bulk and single-cell) and chromatin domains regulated by sphingosine 1-phosphate receptor-1 (S1PR1) in adult mouse aortic endothelial cells. First, S1PR1 regulates NFκB and nuclear glucocorticoid receptor pathways to suppress inflammation-related mRNAs.

Sphingosine 1-Phosphate Receptor Signaling Establishes AP-1 Gradients to Allow for Retinal Endothelial Cell Specialization.

Transcriptional mechanisms that drive angiogenesis and organotypic vascular endothelial cell specialization are poorly understood. Here, we show that retinal endothelial sphingosine 1-phosphate receptors (S1PRs), which restrain vascular endothelial growth factor (VEGF)-induced angiogenesis, spatially restrict expression of JunB, a member of the activator protein 1 (AP-1) family of transcription factors (TFs). Mechanistically, VEGF induces JunB expression at the sprouting vascular front while S1PR-dependent vascular endothelial (VE)-cadherin assembly suppresses JunB expression in the nascent vascular network, thus creating a gradient of this TF.

A Conserved Target Site in HIV-1 Gag RNA is Accessible to Inhibition by Both an HDV Ribozyme and a Short Hairpin RNA.

Antisense-based molecules targeting HIV-1 RNA have the potential to be used as part of gene or drug therapy to treat HIV-1 infection. In this study, HIV-1 RNA was screened to identify more conserved and accessible target sites for ribozymes based on the hepatitis delta virus motif. Using a quantitative screen for effects on HIV-1 production, we identified a ribozyme targeting a highly conserved site in the Gag coding sequence with improved inhibitory potential compared to our previously described candidates targeting the overlapping Tat/Rev coding sequence.

Design and evaluation of clinically relevant SOFA-HDV ribozymes targeting HIV RNA.

Nucleic acid therapies targeting HIV replication have the potential to be used in conjunction with or in place of the standard small-molecule therapies. Among the different classes of nucleic acid therapies, several ribozymes (Rzs, RNA enzymes) have been developed to target HIV RNA. The design of Rzs targeting HIV RNA is complicated by the sequence diversity of viral strains and the structural diversity of their target sites.

Target-induced SOFA-HDV ribozyme.

Small cis-acting ribozymes have been converted into trans-acting ribozymes possessing the ability to cleave RNA substrates. The Hepatitis Delta Virus (HDV) ribozyme is one of the rare examples of these that is derived from an RNA species that is found in human cells. Consequently, it possesses the natural ability to function in the presence of human proteins in addition to an outstanding stability in human cells, two significant advantages in its use.

Selection of the most potent specific on/off adaptor-hepatitis delta virus ribozymes for use in gene targeting.

The Hepatitis Delta Virus (HDV) ribozyme, which is well adapted to the environment of the human cell, is an excellent candidate for the future development of gene-inactivation systems. On top of this, a new generation of HDV ribozymes now exists that benefits from the addition of a specific on/off adaptor (specifically the SOFA-HDV ribozymes) which greatly increases both the ribozyme's specificity and its cleavage activity. Unlike RNAi and hammerhead ribozymes, the designing of SOFA-HDV ribozymes to cleave, in trans, given RNA species has never been the object of a systematic optimization study, even with their recent use for the gene knockdown of various targets.

Investigating a new generation of ribozymes in order to target HCV.

For a long time nucleic acid-based approaches directed towards controlling the propagation of Hepatitis C Virus (HCV) have been considered to possess high potential. Towards this end, ribozymes (i.e.