Developing potent backbone cyclic peptides bearing the shared epitope sequence as rheumatoid arthritis drug-leads

Rheumatoid arthritis (RA) is a common human leukocyte antigen-associated disease. Most RA patients have a five-residue sequence motif called the shared epitope (SE) in the DRβ-chain of the HLA-DRB1 protein. The SE was found to activate nitric oxide (NO) production, suggesting a possible mechanism for RA development. The native conformation of the SE is presumed to be an α-helix, thus using cyclic peptides to stabilize this conformation may produce a potent SE mimetic which will have drug-like properties. We present the development of a backbone cyclic SE mimetic that activates NO production in the low nM range. Circular dichroism analysis revealed a conformational change from for the parent linear peptides to the cyclic analogs. The most active cyclic analog is completely stable towards trypsin/chymotrypsin degradation while the linear 15-mer analogs completely degraded within 30 min. The outcome of this study is a potent cyclic peptide with drug-like properties that can be used as a template for drug development.     

Metabolic disturbances associated with systemic lupus erythematosus

The metabolic disturbances that underlie systemic lupus erythematosus are currently unknown. A metabolomic study was executed, comparing the sera of 20 SLE patients against that of healthy controls, using LC/MS and GC/MS platforms. Validation of key differences was performed using an independent cohort of 38 SLE patients and orthogonal assays. SLE sera showed evidence of profoundly dampened glycolysis, Krebs cycle, fatty acid β oxidation and amino acid metabolism, alluding to reduced energy biogenesis from all sources. Whereas long-chain fatty acids, including the n3 and n6 essential fatty acids, were significantly reduced, medium chain fatty acids and serum free fatty acids were elevated. The SLE metabolome exhibited profound lipid peroxidation, reflective of oxidative damage. Deficiencies were noted in the cellular anti-oxidant, glutathione, and all methyl group donors, including cysteine, methionine, and choline, as well as phosphocholines. The best discriminators of SLE included elevated lipid peroxidation products, MDA, gamma-glutamyl peptides, GGT, leukotriene B4 and 5-HETE. Importantly, similar elevations were not observed in another chronic inflammatory autoimmune disease, rheumatoid arthritis. To sum, comprehensive profiling of the SLE metabolome reveals evidence of heightened oxidative stress, inflammation, reduced energy generation, altered lipid profiles and a pro-thrombotic state. Resetting the SLE metabolome, either by targeting selected molecules or by supplementing the diet with essential fatty acids, vitamins and methyl group donors offers novel opportunities for disease modulation in this disabling systemic autoimmune ailment.     

Simultaneous and selective inference: Current successes and future challenges

The previous decade can be viewed as a second golden for era Multiple Comparisons research. I argue that much of the success stems from our being able to address real current needs. At the same time, this success generated a plethora of concepts for error rate and power, as well as multiplicity of methods for addressing them. These confuse the users of our methodology and pose a threat. To avoid the threat, it is our responsibility to match our theoretical goals to the goals of the users of statistics. Only then should we match the methods to the theoretical goals. Considerations related to such needs are discussed: simultaneous inference or selective inference, testing or estimation, decision making or scientific reporting. I then further argue that the vitality of our field in the future - as a research area - depends upon our ability to continue and address the real needs of statistical analyses in current problems. Two application areas offering new challenges have received less attention in our community to date are discussed. Safety analysis in clinical trials, where I offer an aggregated safety assessment methodology and functional Magnetic Resonance Imaging.     

Vipera aspis venom reduces lethality and down-regulates tumor necrosis factor-α in a rat model of LPS-induced sepsis

Objectives: Sepsis and septic shock are major causes of morbidity and mortality in critically-ill patients. Sepsis constitutes the systemic response to infection, that is predominantly mediated by the pro-inflammatory cytokines TNF-α and IL-1β. Hence, cytokine modulation provides a promising target for the treatment of sepsis. In this work we evaluated the effect of a low-dose Vipera aspis venom (VAV) vaccine on survival and cytokine serum levels in a rat model of lipopolysaccharide (LPS)-induced septic shock. Methods: Adult male Wistar rats were given either VAV vaccine or saline, and 2 weeks later half of each group received LPS challenge, and were monitored for mortality, cytokine levels, blood count and chemistry. Results: Survival rate was significantly higher in venom-treated, compared to non-vaccinated septic rats. Furthermore, VAV treatment significantly reduced LPS-associated TNF-α and LDH, without affecting IL-6 and IL-10 levels, and modified WBC and platelet counts. Conclusions: Our data suggest that sub-toxic doses of VAV have a protective effect against LPS-induced septic shock that may be mediated, at least partially, by the modulated TNF-α activity. This study thus offers a novel therapeutic approach for the attenuation of bacteremia-induced septic shock through the modulation of a central pro-inflammatory cytokine by VAV vaccination in mammals.     

The antibody response to a single antigenic determinant of the tobacco mosaic virus protein (TMVP): effects of allotype-linked genes and restricted heterogeneity of the response

The antibody response to a decapeptide antigenic determinant representing residues 103 to 112 of the tobacco mosaic virus protein (TMVP) was studied with the synthetic decapeptide and a panel of its synthetic analogues. The anti-decapeptide response was found to be of restricted heterogeneity and was regulated by heavy chain allotype-linked (V region) genes on at least two levels. One level was whether or not a significant antibody response was made to the decapeptide determinant. Thus, strains with the Igh haplotypes j, o, e, and n were high responders, whereas strains with haplotype Ighb were low responders. The second level of V region gene control was with regard to the fine specificity of the anti-decapeptide antibodies produced. Using the peptide panel to analyze fine specificity, we define two new V region genetic markers, VH-TMVPj and VH-TMVPe.