Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.     

Role of the orbital prefrontal cortex in choice between delayed and uncertain reinforcers: a quantitative analysis

'Inter-temporal choice' refers to choice between two or more outcomes that differ with respect to their sizes, delays, and/or probabilities of occurrence. According to the multiplicative hyperbolic model of inter-temporal choice, the value of a reinforcer increases as a hyperbolic function of its size, and decreases as a hyperbolic function of its delay and the odds against its occurrence. These functions, each of which contains a single discounting parameter, are assumed to combine multiplicatively to determine the overall value of the reinforcer. The model gives rise to a quantitative methodology for analysing inter-temporal choice, based on a family of linear null equations which describe performance under conditions of indifference, when the values of the reinforcers are assumed to be equal. This approach was used to examine the effect of lesions of the orbital prefrontal cortex (OPFC) on inter-temporal choice in rats. Under halothane anaesthesia, rats received injections of the excitotoxin quinolinate into the OPFC or sham lesions. They were trained to press two levers (A and B) for food-pellet reinforcers in discrete-trials schedules. In free-choice trials, a press on A resulted in delivery of a pellet after a delay d(A) with a probability P=0.5; a press on B resulted in delivery of a pellet with a probability P=1 after a delay d(B). d(B) was increased progressively across successive blocks of six trials in each session, while d(A) was manipulated systematically across phases of the experiment. The indifference delays, d(B(50)) (value of d(B) corresponding to 50% choice of B) was estimated for each rat in each phase. Linear functions of d(B(50)) versus d(A) were derived, and the parameters of the function compared between the groups. In both groups, d(B(50)) increased linearly with d(A). The slope of the linear function was significantly steeper in the lesioned group than in the sham-lesioned group, whereas the intercept did not differ significantly between the groups. Analysis based on the relevant null equation indicated that the lesion of the OPFC increased the rate of both delay and odds discounting. Possible implications of the results for interpreting the effects of OPFC lesions on inter-temporal choice behaviour in man are discussed.     

The monotreme genome: a patchwork of reptile, mammal and unique features?

The first specimen of platypus (Ornithorhynchus anatinus) that reached Britain in the late 18th century was regarded a scientific hoax. Over decades the anatomical characteristics of these unique mammals, such as egg laying and the existence of mammary glands, were hotly debated before they were accepted. Within the last 40 years, more and more details of monotreme physiology, histology, reproduction and genetics have been revealed. Some show similarities with birds or reptiles, some with therian mammals, but many are very specific to monotremes. The genome is no exception to monotreme uniqueness. An early opinion was that the karyotype, composed of a few large chromosomes and many small ones, resembled bird and reptile macro- and micro-chromosomes. However, the platypus genome also features characteristics that are not present in other mammals, such as a complex translocation system. The sex chromosome system is still not resolved. Nothing is known about dosage compensation and, unlike in therian mammals, there seems to be no genomic imprinting. In this article we will recount the mysteries of the monotreme genome and describe how we are using recently developed technology to identify chromosomes in mitosis, meiosis and sperm, to map genes to chromosomes, to unravel the sex chromosome system and the translocation chain and investigate X inactivation and genomic imprinting in monotremes.     

Hepatocyte growth factor/scatter factor and its interaction with heparan sulphate and dermatan sulphate

Hepatocyte growth factor (HGF)/scatter factor (SF) is a unique growth factor, in that it binds both heparan sulphate (HS) and dermatan sulphate (DS). The sequences in HS and DS that specifically interact with and modulate HGF/SF activity have not yet been fully identified. Ascidian DS, which uniquely possesses O-sulphation at C-6 (and not C-4) of its N -acetylgalactosamine unit, was analysed for HGF/SF-binding activity in the biosensor. The kinetic analysis revealed a strong, biologically relevant interaction with an equilibrium dissociation constant ( K (d)) of approx. 1 nM. An Erk activation assay also demonstrated stimulation of the MAP kinase pathway downstream of the Met receptor following addition of both HGF/SF and ascidian DS to the glycosaminoglycan-deficient CHO-745 mutant cell line. Furthermore, the activation of Met and the MAP kinase pathway by HGF/SF and ascidian DS leads to a cellular response in the form of migration.     

The generation and characterization of antagonist RNA aptamers to human oncostatin M

Oncostatin M (OSM) is a multifunctional member of the interleukin-6 cytokine family. OSM has been implicated as a powerful proinflammatory mediator and may represent a potentially important, novel therapeutic opportunity for treatment of established rheumatoid arthritis. To further investigate the role of OSM in inflammatory disorders, we have isolated a series of RNA aptamers that bind specifically to human OSM. The highest affinity aptamer, designated ADR58, has been characterized in a series of in vitro and cell based assays. ADR58 has an affinity of 7 nm for human OSM, and it can antagonize OSM binding to the gp130 receptor and specifically antagonize OSM mediated signaling. The aptamer has been truncated in length to 33 bases, all pyrimidine positions are substituted with 2' fluorine, and 14 of 18 purine positions have been substituted with 2' O-methyl to increase stability toward nucleases. This truncated, modified form of ADR58 retains complete affinity and functional activity for OSM. This aptamer may be used as a tool to further investigate the role of OSM in inflammatory disorders and may also have role as a therapeutic agent.     

The ternary transformation system: constitutive virG on a compatible plasmid dramatically increases Agrobacterium-mediated plant transformation

This paper describes a so-called ternary transformation system for plant cells. We demonstrate that Agrobacterium tumefaciens strain LBA4404 supplemented with a constitutive virG mutant gene (virGN54D) on a compatible plasmid is capable of very efficient T-DNA transfer to a diverse range of plant species. For the plant species Catharanthus roseus it is shown that increased T-DNA transfer results in increased stable transformation frequencies. Analysis of stably transformed C. roseus cell lines showed that, although the T-DNA transfer frequency is greatly enhanced by addition of virGN54D, only one or a few T-DNA copies are stably integrated into the plant genome. Thus, high transformation frequencies of different plant species can be achieved by introduction of a ternary plasmid carrying a constitutive virG mutant into existing A. tumefaciens strains in combination with standard binary vectors.     

Variability in the Effect of 5-HTTLPR on Depression in a Large European Population: The Role of Age,Symptom Profile,Type and Intensity of Life Stressors

Background

Although 5-HTTLPR has been shown to influence the risk of life stress-induced depression in the majority of studies, others have produced contradictory results, possibly due to weak effects and/or sample heterogeneity.

Methods

In the present study we investigated how age, type and intensity of life-stressors modulate the effect of 5-HTTLPR on depression and anxiety in a European population cohort of over 2300 subjects. Recent negative life events (RLE), childhood adversity (CHA), lifetime depression, Brief Symptoms Inventory (BSI) depression and anxiety scores were determined in each subject. Besides traditional statistical analysis we calculated Bayesian effect strength and relevance of 5-HTTLPR genotypes in specified models.

Results

The short (s) low expressing allele showed association with increased risk of depression related phenotypes, but all nominally significant effects would turn to non-significant after correction for multiple testing in the traditional analysis. Bayesian effect strength and relevance analysis, however, confirmed the role of 5-HTTLPR. Regarding current (BSI) and lifetime depression 5-HTTLPR-by-RLE interactions were confirmed. Main effect, with other words direct association, was supported with BSI anxiety. With more frequent RLE the prevalence or symptoms of depression increased in ss carriers. Although CHA failed to show an interaction with 5-HTTLPR, in young subjects CHA sensitized towards the depression promoting effect of even mild RLE. Furthermore, the direct association of anxiety with the s allele was driven by young (≤30) individuals.

Limitations

Our study is cross-sectional and applies self-report questionnaires.

Conclusions

Albeit 5-HTTLPR has only weak/moderate effects, the s allele is directly associated with anxiety and modulates development of depression in homogeneous subgroups.