<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.

     

Myosin light-chain expression during avian muscle development

Monoclonal antibodies to adult chicken myosin light chains were generated and used to quantitate the types of myosin light-chain (MLC) isoforms expressed during development of the pectoralis major (PM), anterior latissimus dorsi (ALD), and medial adductor (MA) muscles of the chicken. These are muscles which, in the adult, are composed predominantly of fast, slow, and a mixture of fiber types, respectively. Three distinct phases of MLC expression characterized the development of the PM and MA muscles. The first identifiable pase occurred during the period of 5-7 d of incubation in ovo. Extracts of muscles from the pectoral region (which included the presumptive PM muscle) contained only fast MLC isoforms. This period of exclusive fast light-chain synthesis was followed by a phase (8- 12 d of incubation in ovo) in which coexpression of both fast and slow MLC isoforms was apparent in both PM and MA muscles. During the period, the composition of both fast and slow MLC isoforms in the PM and MA muscles was identical. Beginning at day 12 in ovo, the ALD was also subjected to immunochemical analyses. The proportion of fast and slow MLCs in this muscle at day 12 was similar to that present in the other muscles studied. The third development phase of MLC expression began at approximately 12 d of incubation in ovo and encompassed the transition in MLC composition to the isoform patterns incubation in ovo and encompassed the transition in MLC composition to the isoform patterns typical of adult muscle. During this period, the relative proportion of slow MLC rose in both the MA and ALD and fell in the PM. By day 16, the third fast light chain, LC(3f), was apparent in extracts of both the PM and MA. These results show that there is a developmental progression in the expression of MLC in the two avian muscles studied from day 5 in ovo; first, only fast MLCs are accumulated, then both fast and slow MLC isoforms are expressed. Only during the latter third of development in ovo is the final MLC isoform pattern characteristic of a particular muscle type expressed.     

The signaling adapter p62 is an important mediator of T helper 2 cell function and allergic airway inflammation

Na?ve T helper (Th) cells differentiate in response to antigen stimulation into either Th1 or Th2 effector cells, which are characterized by the secretion of different set of cytokines. Th2 differentiation, which is critical for allergic airway disease, is triggered by signals of the T-cell receptor (TCR) and the cytokines generated during polarization, particularly IL-4. We determine here the potential role of the signaling adapter p62 in T-cell polarization. We report using p62-/- mice and cells that p62 acts downstream TCR activation, and is important for Th2 polarization and asthma, playing a significant role in the control of the sustained activation of NF-kappaB and late synthesis of GATA3 and IL-4 by participating in the activation of the IKK complex.     

Using the ratio of means as the effect size measure in combining results of microarray experiments

Background  

Development of efficient analytic methodologies for combining microarray results is a major challenge in gene expression analysis. The widely used effect size models are thought to provide an efficient modeling framework for this purpose, where the measures of association for each study and each gene are combined, weighted by the standard errors. A significant disadvantage of this strategy is that the quality of different data sets may be highly variable, but this information is usually neglected during the integration. Moreover, it is widely known that the estimated standard deviations are probably unstable in the commonly used effect size measures (such as standardized mean difference) when sample sizes in each group are small.     

Mature-onset obesity and insulin resistance in mice deficient in the signaling adapter p62

Signaling cascades that control adipogenesis are essential in the regulation of body weight and obesity. The adaptor p62 controls pathways that modulate cell differentiation. We report here that p62(-/-) mice develop mature-onset obesity, leptin resistance, as well as impaired glucose and insulin intolerance. The metabolic rate was significantly reduced in p62(-/-) nonobese mice, which displayed increased mRNA levels of PPAR-gamma and reduced levels of UCP-1 in adipose tissue. Basal activity of ERK was enhanced in fat from nonobese mutant mice. Embryo fibroblasts from p62(-/-) mice differentiated better than the wild-type controls into adipocytes, which was abrogated by pharmacological inhibition of the ERK pathway. p62 is induced during adipocyte differentiation and inhibits ERK activation by direct interaction. We propose that p62 normally antagonizes basal ERK activity and adipocyte differentiation and that its loss leads to the hyperactivation of ERK that favors adipogenesis and obesity.     

A dominant negative protein kinase C zeta subspecies blocks NF-kappa B activation.

Nuclear factor kappa B (NF-kappa B) plays a critical role in the regulation of a number of genes. NF-kappa B is a heterodimer of 50- and 65-kDa subunits sequestered in the cytoplasm complexed to inhibitory protein I kappa B. Following stimulation of cells, I kappa B dissociates from NF-kappa B, allowing its translocation to the nucleus, where it carries out the transactivation function. The precise mechanism controlling NF-kappa B activation and the involvement of members of the protein kinase C (PKC) family of isotypes have previously been investigated. It was found that phorbol myristate acetate, (PMA) which is a potent stimulant of phorbol ester-sensitive PKC isotypes, activates NF-kappa B. However, the role of PMA-sensitive PKCs in vivo is not as apparent. It has recently been demonstrated in the model system of Xenopus laevis oocytes that the PMA-insensitive PKC isotype, zeta PKC, is a required step in the activation of NF-kappa B in response to ras p21. We demonstrate here that overexpression of zeta PKC is by itself sufficient to stimulate a permanent translocation of functionally active NF-kappa B into the nucleus of NIH 3T3 fibroblasts and that transfection of a kinase-defective dominant negative mutant of zeta PKC dramatically inhibits the kappa B-dependent transactivation of a chloramphenicol acetyltransferase reporter plasmid in NIH 3T3 fibroblasts. All these results support the notion that zeta PKC plays a decisive role in NF-kappa B regulation in mammalian cells.