Treatment with apolipoprotein A-1 mimetic peptide reduces lupus-like manifestations in a murine lupus model of accelerated atherosclerosis

Introduction

The purpose of this study was to evaluate the effects of L-4F, an apolipoprotein A-1 mimetic peptide, alone or with pravastatin, in apoE^-/-Fas^-/-C57BL/6 mice that spontaneously develop immunoglobulin G (IgG) autoantibodies, glomerulonephritis, osteopenia, and atherosclerotic lesions on a normal chow diet.

Methods

Female mice, starting at eight to nine weeks of age, were treated for 27 weeks with 1) pravastatin, 2) L-4F, 3) L-4F plus pravastatin, or 4) vehicle control, followed by disease phenotype assessment.

Results

In preliminary studies, dysfunctional, proinflammatory high-density lipoproteins (piHDL) were decreased six hours after a single L-4F, but not scrambled L-4F, injection in eight- to nine-week old mice. After 35 weeks, L-4F-treated mice, in the absence/presence of pravastatin, had significantly smaller lymph nodes and glomerular tufts (P_{L, LP} < 0.05), lower serum levels of IgG antibodies to double stranded DNA (dsDNA) (P_L < 0.05) and oxidized phospholipids (oxPLs) (P_{L, LP} < 0.005), and elevated total and vertebral bone mineral density (P_{L, LP} < 0.01) compared to vehicle controls. Although all treatment groups presented larger aortic root lesions compared to vehicle controls, enlarged atheromas in combination treatment mice had significantly less infiltrated CD68⁺ macrophages (P_LP < 0.01), significantly increased mean α-actin stained area (P_LP < 0.05), and significantly lower levels of circulating markers for atherosclerosis progression, CCL19 (P_{L, LP} < 0.0005) and VCAM-1 (P_L < 0.0002).

Conclusions

L-4F treatment, alone or with pravastatin, significantly reduced IgG anti-dsDNA and IgG anti-oxPLs, proteinuria, glomerulonephritis, and osteopenia in a murine lupus model of accelerated atherosclerosis. Despite enlarged aortic lesions, increased smooth muscle content, decreased macrophage infiltration, and decreased pro-atherogenic chemokines in L-4F plus pravastatin treated mice suggest protective mechanisms not only on lupus-like disease, but also on potential plaque remodeling in a murine model of systemic lupus erythematosus (SLE) and accelerated atherosclerosis.     

Molecular architecture of the ribosome‐bound Hepatitis C Virus internal ribosomal entry site RNA

Internal ribosomal entry sites (IRESs) are structured cis‐acting RNAs that drive an alternative, cap‐independent translation initiation pathway. They are used by many viruses to hijack the translational machinery of the host cell. IRESs facilitate translation initiation by recruiting and actively manipulating the eukaryotic ribosome using only a subset of canonical initiation factor and IRES transacting factors. Here we present cryo‐EM reconstructions of the ribosome 80S‐ and 40S‐bound Hepatitis C Virus (HCV) IRES. The presence of four subpopulations for the 80S•HCV IRES complex reveals dynamic conformational modes of the complex. At a global resolution of 3.9 Å for the most stable complex, a derived atomic model reveals a complex fold of the IRES RNA and molecular details of its interaction with the ribosome. The comparison of obtained structures explains how a modular architecture facilitates mRNA loading and tRNA binding to the P‐site. This information provides the structural foundation for understanding the mechanism of HCV IRES RNA‐driven translation initiation.     

Redox state regulates binding of p53 to sequence-specific DNA, but not to non-specific or mismatched DNA.

Redox modulation of wild-type p53 plays a role in sequence-specific DNA binding in vitro . Reduction produces a DNA-binding form of the protein while oxidation produces a non-DNA-binding form. Primer extension analysis reveals that increasing concentrations of reduced p53 result in enhanced protection of the consensus sequence, while increasing concentrations of oxidized p53 confer minimal protection of the consensus sequence. DNA binding by oxidized p53 is, therefore, not sequence-specific. In contrast, there is no observable difference in the binding of oxidized p53 and reduced p53 to double-stranded non-specific or mismatched DNA in gel mobility shift assays. Both forms of p53 bind equally well, suggesting that redox modulation of p53 does not play a role in its binding to non-specific or mismatched DNA. In view of the in vitro evidence that redox state influences the sequence-specific DNA-binding of p53, we have examined the effect of oxidative stress on the in vivo ability of p53 to bind to and transactivate PG13-CAT, a reporter construct containing multiple copies of the p53 consensus binding site linked to the chloramphenicol acetyltransferase gene. Hydrogen peroxide treatment of cells cotransfected with p53 results in a marked decrease in CAT activity, suggesting that oxidation of p53 decreases the ability of the protein to bind to consensus DNA and transactivate target genes in vivo.     

Hormone-regulated expression and distribution of versican in mouse uterine tissues

Background  

Remodeling of the extracellular matrix is one of the most striking features observed in the uterus during the estrous cycle and after hormone replacement. Versican (VER) is a hyaluronan-binding proteoglycan that undergoes RNA alternative splicing, generating four distinct isoforms. This study analyzed the synthesis and distribution of VER in mouse uterine tissues during the estrous cycle, in ovariectomized (OVX) animals and after 17beta-estradiol (E2) and medroxyprogesterone (MPA) treatments, either alone or in combination.     

Structural determinants of Cys2His2 zinc fingers.

Two mutants of the zinc finger peptide Xfin-31 (Ac-YKCGLCERSFVEKSALSRHQRVHKN-CONH2) containing alterations to the conserved hydrophobic core have been constructed and their zinc-bound structures investigated by 1H NMR techniques. In the first (Xfin-31B) a double mutation R8F/F10G places the conserved core aromatic residue at position 8 rather than position 10. In the second (Xfin-31C), Phe-10 is replaced by Leu. A qualitative analysis of 1H chemical shifts, NOE connectivities and coupling constants indicates that the global folds of both mutants are similar to that of the wild-type protein. However, amide exchange rates suggest that the F10L mutant is much less stable than either the wild-type or the R8F/F10G mutant.     

<Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis> chloroplasts express an orally immunogenic protein targeting the p210 epitope implicated in atherosclerosis immunotherapies

Key message

An algae-based vaccine model against atherosclerosis was developed with positive findings in terms of antigen yield and immunogenicity in mouse.

Abstract

Several immunotherapies against atherosclerosis have been evaluated at the preclinical level thus far, with some of them currently under evaluation in clinical trials. In particular, the p210 epitope from ApoB100 is known to elicit atheroprotective responses. Considering that Chlamydomonas reinhardtii is an attractive host for the production and delivery of subunit vaccines, in this study a chimeric protein consisting of the B subunit of the cholera toxin and the p210 epitope from ApoB100 (CTB:p210) has been expressed in C. reinhardtii chloroplast as an attempt to establish an oral vaccine candidate against atherosclerosis. The Chlamydomonas-made CTB:p210 protein was successfully expressed at levels of up to 60 µg per g of fresh weight biomass. The antigenic activity of the CTB and the p210 moiety was preserved in the CTB:p210 chimera. Moreover the algae-made CTB:p210 showed an immunogenic activity, when orally administered to BALB/c mice, as evidenced the presence of anti-p210 serum antibodies in mice treated with the algae-derived CTB:p210. The antibody response lasts for at least 80 days after the last boost. This experimental model is proposed as a convenient tool in the development of low cost atherosclerosis vaccines of easy compliance and friendly delivery. Further studies will determine the therapeutic potential of this algae-made vaccine in atherosclerosis animal models.