An Eight-Gene Blood Expression Profile Predicts the Response to Infliximab in Rheumatoid Arthritis

Background

TNF alpha blockade agents like infliximab are actually the treatment of choice for those rheumatoid arthritis (RA) patients who fail standard therapy. However, a considerable percentage of anti-TNF alpha treated patients do not show a significant clinical response. Given that new therapies for treatment of RA have been recently approved, there is a pressing need to find a system that reliably predicts treatment response. We hypothesized that the analysis of whole blood gene expression profiles of RA patients could be used to build a robust predictor to infliximab therapy.

Methods and Findings

We performed microarray gene expression analysis on whole blood RNA samples from RA patients starting infliximab therapy (n = 44). The clinical response to infliximab was determined at week 14 using the EULAR criteria. Blood cell populations were determined using flow cytometry at baseline, week 2 and week 14 of treatment. Using complete cross-validation and repeated random sampling we identified a robust 8-gene predictor model (96.6% Leave One Out prediction accuracy, P = 0.0001). Applying this model to an independent validation set of RA patients, we estimated an 85.7% prediction accuracy (75–100%, 95% CI). In parallel, we also observed a significantly higher number of CD4+CD25+ cells (i.e. regulatory T cells) in the responder group compared to the non responder group at baseline (P = 0.0009).

Conclusions

The present 8-gene model obtained from whole blood expression efficiently predicts response to infliximab in RA patients. The application of the present system in the clinical setting could assist the clinician in the selection of the optimal treatment strategy in RA.     

Synthesis and DNA binding properties of DNA-PNA chimeras

A systematic study to evaluate the ability of 5'-DNA-3'-p-(N)-PNA-(C) chimeras to form triple helix structures has been undertaken. Preliminary results carried out on a 16-mer chimera with three PNA monomers at the 3'-end showed the formation of a stable DNA-PNA/DNA/DNA triplex, having similar conformational behaviour to a canonical DNA/DNA/DNA triplex.     

A simple protocol for combinatorial cyclic depsipeptide libraries sequencing by matrix‐assisted laser desorption/ionisation mass spectrometry

Short cyclic peptides have a great interest in therapeutic, diagnostic and affinity chromatography applications. The screening of ‘one‐bead‐one‐peptide’ combinatorial libraries combined with mass spectrometry (MS) is an excellent tool to find peptides with affinity for any target protein. The fragmentation patterns of cyclic peptides are quite more complex than those of their linear counterparts, and the elucidation of the resulting tandem mass spectra is rather more difficult. Here, we propose a simple protocol for combinatorial cyclic libraries synthesis and ring opening before MS analysis. In this strategy, 4‐hydroxymethylbenzoic acid, which forms a benzyl ester with the first amino acid, was used as the linker. A glycolamidic ester group was incorporated after the combinatorial positions by adding glycolic acid. The library synthesis protocol consisted in the following: (i) incorporation of Fmoc‐Asp[2‐phenylisopropyl (OPp)]‐OH to Ala‐Gly‐oxymethylbenzamide‐ChemMatrix, (ii) synthesis of the combinatorial library, (iii) assembly of a glycolic acid, (iv) couple of an Ala residue in the N‐terminal, (v) removal of OPp, (vi) peptide cyclisation through side chain Asp and N‐Ala amino terminus and (vii) removal of side chain protecting groups. In order to simultaneously open the ring and release each peptide, benzyl and glycolamidic esters were cleaved with ammonia. Peptide sequences could be deduced from the tandem mass spectra of each single bead evaluated. The strategy herein proposed is suitable for the preparation of one‐bead‐one‐cyclic depsipeptide libraries that can be easily open for its sequencing by matrix‐assisted laser desorption/ionisation MS. It employs techniques and reagents frequently used in a broad range of laboratories without special expertise in organic synthesis. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

Illustrations pratiques – aspects pratiques et réglementaires

Quality and regulatory controls in hybrid nuclear medicine, layout and installations constraints, Diagnostic Reference values and regulatory and mandatory information in the medical report are presented in that part.     

Biaryl analogues of teriflunomide as potent DHODH inhibitors

The structure–activity relationships of a novel series of biaryl dihydroorotate dehydrogenase (DHODH) inhibitors related to teriflunomide are disclosed. These biaryl derivatives were the result of structure-based design and proved to be potent DHODH inhibitors which in addition showed good antiproliferative activities on peripheral blood mononuclear cells and good efficacies in vivo in the rat adjuvant-induced-arthritis model.     

Distribution physiologique cérébrale et corps entier du 18F-DPA-714 en TEP/TDM

ObjectiveTo investigate the physiological biodistribution of N,N-diethyl-2-(2 – (4 – (2-fluoroethoxy) phenyl) -5,7-dimethylpyrazolo [1,5] pyrimidin-3-yl) acetamide labeled with fluorine 18 (¹⁸F-DPA-714) in humans, by PET/CT in the brain and the whole body. The DPA-714 is a ligand of the translocator protein (Translocator Protein kDa or TSPO), protein overexpressed by microglia in case of neuroinflammation.Materials and methodsDynamic PET/CT brain acquisitions were performed in six healthy volunteers for 90 minutes after intravenous injection of ¹⁸F-DPA-714. Brain biodistribution of ¹⁸F-DPA-714 was assessed visually and using regions of interest (ROI), according to MNI AAL guidelines in order to obtain the activity/time curves for each brain region predefined. One of the subjects was also included whole body PET/CT acquisitions 1 hour after injection of ¹⁸F-DPA-714, allowing visual analysis and semi-quantitative distribution of the tracer, by definition of ROI and SUVs max computation.ResultsThe maximum brain uptake of ¹⁸F-DPA-714 was visualized at 3.5 minutes after injection, gray matter, mostly thalamic. This peak was followed by two elimination phases: an initial rapid phase (3.5 to 35 minutes) and a slower phase until the end of recording. Uptake of ¹⁸F-DPA-714 was generally consistent across brain structures analyzed. The whole body images show significant activity in the gallbladder, spine and salivary glands under the jaw, in accordance with previous published studies using other radioligands for TSPO.ConclusionThis very preliminary study confirms that the brain biodistribution of ¹⁸F-DPA-714 makes it an interesting marker of neuroinflammation. This work allows to recommend a PET protocol acquisition. However, it now seems necessary to implement these findings in patients referred for brain conditions.     

Design and synthesis of spirotryprostatin-inspired diketopiperazine systems from prolyl spirooxoindolethiazolidine derivatives

Based on the spirotryprostatin-A structure, we designed, synthesized, and evaluated different series of compounds belonging to the diketopiperazine structural class as potential cell cycle modulators and cytotoxic agents. Starting from the spirooxoindolthiazolidine scaffold, amide coupling with Pro derivatives and intramolecular cyclization reactions are suitable synthetic methods to generate chemically diverse diketopiperazine system, such as hexahydropyrrolo[1,2-a][1,3]thiazolo[3,2-d]pyrazine-5,10-dione (structure I), hexahydropyrrolo[1,2-a] [1,3]thiazolo[3,4-d]pyrazine-5,10-dione (structure II) and spiroindol-2-one[3,3′]hexahydro-5,10H-pyrrolo[1,2-a][1,3]thiazolo[3,4-d]pyrazine-5,10-dione (structure III). Some of these compounds, especially those who belong to the series I and II, showed interesting cytotoxic activity.     

Euplotespora binucleata n. gen., n. sp. (Protozoa: Microsporidia), a parasite infecting the hypotrichous ciliate Euplotes woodruffi, with observations on microsporidian infections in ciliophora

A new microsporidian species, Euplotespora binucleata n. gen., n. sp., from the brackish-water ciliate Euplotes woodruffi is described and defined on the basis of life history characteristics, light and electron microscopic features, and small subunit (SSU) ribosomal DNA (rDNA) sequencing. The life cycle of E. binucleata n. sp. probably has rather short merogonic and relatively long sporogonic phases. Some uninuclear meronts and sporonts, along with diplokaryotic sporoblasts and spores, were found in experimentally infected host cells. Such a peculiar life cycle has been induced experimentally in Euplotes eurystomus and constitutively microsporidian-free stocks of E. woodruffi. Spores of E. binucleata n. sp. are monomorphic, ovoid-cylindrical in shape, 3.44+/-0.17 x 1.65+/-0.22 microm in size, and characterized by a diplokaryotic condition and a large posterior vacuole. The polar tube is isofilar, 4.5-5.5 microm in length when ejected, and lacking a distinctive coiled region (half-coiled). The polaroplast is divided into two regions: the anterior part has a few lamellae close to the anchoring disc; and the posterior part is a rounded body (sack), about one-quarter of the spore length. Spores do not appear to cluster together as a group. Each spore is surrounded by a sporophorous membrane closely adjacent to the exospore layer. A phylogenetic analysis of SSU rDNA sequences by different methods placed E. binucleata n. sp. in a clade with representatives of the microsporidian genera Cystosporogenes and Vittaforma. Observations of microsporidia in several other ciliates are discussed in view of the microsporidian infection frequency in the phylum Ciliophora.