Gene Expression and Thiopurine Metabolite Profiling in Inflammatory Bowel Disease – Novel Clues to Drug Targets and Disease Mechanisms?

Gene expression and thiopurine metabolite profiling in inflammatory bowel disease – novel clues to drug targets and disease mechanisms?

PLoS One. 2013; 8(2): e56989
Haglund S, Almer S, Peterson C, Söderman J

Thiopurines are effective to induce and maintain remission in inflammatory bowel disease (IBD). The methyl thioinosine monophosphate (meTIMP)/6-thioguanine nucleotide (6-TGN) concentration ratio has been associated with drug efficacy. Here we explored the molecular basis of differences in metabolite profiles and in relation to disease activity.Transcriptional profiles in blood samples from an exploratory IBD-patient cohort (n?=?21) with a normal thiopurine S-methyltransferase phenotype and meTIMP/6-TGN ratios >20, 10.0-14.0 and ?4, respectively, were assessed by hybridization to microarrays. Results were further evaluated with RT qPCR in an expanded patient cohort (n?=?54). Additionally, 30 purine/thiopurine related genes were analysed separately.Among 17 genes identified by microarray-screening, there were none with a known relationship to pathways of purines/thiopurines. For nine of them a correlation between expression level and the concentration of meTIMP, 6-TGN and/or the meTIMP/6-TGN ratio was confirmed in the expanded cohort. Nine of the purine/thiopurine related genes were identified in the expanded cohort to correlate with meTIMP, 6-TGN and/or the meTIMP/6-TGN ratio. However, only small differences in gene expression levels were noticed over the three different metabolite profiles. The expression levels of four genes identified by microarray screening (PLCB2, HVCN1, CTSS, and DEF8) and one purine/thiopurine related gene (NME6) correlated significantly with the clinical activity of Crohn’s disease. Additionally, 16 of the genes from the expanded patient cohort interacted in networks with candidate IBD susceptibility genes.Seventeen of the 18 genes which correlated with thiopurine metabolite levels also correlated with disease activity or participated in networks with candidate IBD susceptibility genes involved in processes such as purine metabolism, cytokine signaling, and functioning of invariant natural killer T cells, T cells and B cells. Therefore, we conclude that the identified genes to a large extent are related to drug targets and disease mechanisms of IBD. HubMed – drug


Improved BM212 MmpL3 Inhibitor Analogue Shows Efficacy in Acute Murine Model of Tuberculosis Infection.

PLoS One. 2013; 8(2): e56980
Poce G, Bates RH, Alfonso S, Cocozza M, Porretta GC, Ballell L, Rullas J, Ortega F, De Logu A, Agus E, La Rosa V, Pasca MR, De Rossi E, Wae B, Franzblau SG, Manetti F, Botta M, Biava M

1,5-Diphenyl pyrroles were previously identified as a class of compounds endowed with high in vitro efficacy against M. tuberculosis. To improve the physical chemical properties and drug-like parameters of this class of compounds, a medicinal chemistry effort was undertaken. By selecting the optimal substitution patterns for the phenyl rings at N1 and C5 and by replacing the thiomorpholine moiety with a morpholine one, a new series of compounds was produced. The replacement of the sulfur with oxygen gave compounds with lower lipophilicity and improved invitro microsomal stability. Moreover, since the parent compound of this family has been shown to target MmpL3, mycobacterial mutants resistant to two compounds have been isolated and characterized by sequencing the mmpL3 gene; all the mutants showed point mutations in this gene. The best compound identified to date was progressed to dose-response studies in an acute murine TB infection model. The resulting ED(99) of 49 mg/Kg is within the range of commonly employed tuberculosis drugs, demonstrating the potential of this chemical series. The in vitro and in vivo target validation evidence presented here adds further weight to MmpL3 as a druggable target of interest for anti-tubercular drug discovery. HubMed – drug


Replication of Association between Schizophrenia and Chromosome 6p21-6p22.1 Polymorphisms in Chinese Han Population.

PLoS One. 2013; 8(2): e56732
Zhang Y, Lu T, Yan H, Ruan Y, Wang L, Zhang D, Yue W, Lu L

Chromosome 6p21-p22.1, spanning the extended major histocompatibility complex (MHC) region, is a highly polymorphic, gene-dense region. It has been identified as a susceptibility locus of schizophrenia in Europeans, Japanese, and Chinese. In our previous two-stage genome-wide association study (GWAS), polymorphisms of zinc finger with KRAB and SCAN domains 4 (ZKSCAN4), nuclear factor-?B-activating protein-like (NKAPL), and piggyBac transposable element derived 1 (PGBD1), localized to chromosome 6p21-p22.1, were strongly associated with schizophrenia. To further investigate the association between polymorphisms at this locus and schizophrenia in the Chinese Han population, we selected eight other single-nucleotide polymorphisms (SNPs) distributed in or near these genes for a case-control association study in an independent sample of 902 cases and 1,091 healthy controls in an attempt to replicate the GWAS results. Four of these eight SNPs (rs12214383, rs1150724, rs3800324, and rs1997660) displayed a nominal difference in allele frequencies between the case and control groups. The association between two of these SNPs and schizophrenia were significant even after Bonferroni correction (rs12000: allele A>G, P?=?2.50E-04, odds ratio [OR]?=?1.27, 95% confidence interval [CI]?=?1.12-1.45; rs1150722: allele C>T, P?=?4.28E-05, OR?=?0.55, 95% CI?=?0.41-0.73). Haplotype ATTGACGC, comprising these eight SNPs (rs2235359, rs2185955, rs12214383, rs12000, rs1150724, rs1150722, rs3800324, and rs1997660), was significantly associated with schizophrenia (P?=?6.60E-05). We also performed a combined study of this replication sample and the first-stage GWAS sample. The combined study revealed that rs12000 and rs1150722 were still strongly associated with schizophrenia (rs12000: allele G>A, P(combined)?=?0.0019, OR?=?0.81; rs1150722: allele G>A, P(combined)?=?3.00E-04, OR?=?0.61). These results support our findings that locus 6p21-p22.1 is significantly associated with schizophrenia in the Chinese Han population and encourage further studies of the functions of these genetic factors. HubMed – drug


Parallel screening of wild-type and drug-resistant targets for anti-resistance neuraminidase inhibitors.

PLoS One. 2013; 8(2): e56704
Hsu KC, Hung HC, Horng JT, Fang MY, Chang CY, Li LT, Chen IJ, Chen YC, Chou DL, Chang CW, Hsieh HP, Yang JM, Hsu JT

Infection with influenza virus is a major public health problem, causing serious illness and death each year. Emergence of drug-resistant influenza virus strains limits the effectiveness of drug treatment. Importantly, a dual H275Y/I223R mutation detected in the pandemic influenza A 2009 virus strain results in multidrug resistance to current neuraminidase (NA) drugs. Therefore, discovery of new agents for treating multiple drug-resistant (MDR) influenza virus infections is important. Here, we propose a parallel screening strategy that simultaneously screens wild-type (WT) and MDR NAs, and identifies inhibitors matching the subsite characteristics of both NA-binding sites. These may maintain their potency when drug-resistant mutations arise. Initially, we analyzed the subsite of the dual H275Y/I223R NA mutant. Analysis of the site-moiety maps of NA protein structures show that the mutant subsite has a relatively small volume and is highly polar compared with the WT subsite. Moreover, the mutant subsite has a high preference for forming hydrogen-bonding interactions with polar moieties. These changes may drive multidrug resistance. Using this strategy, we identified a new inhibitor, Remazol Brilliant Blue R (RB19, an anthraquinone dye), which inhibited WT NA and MDR NA with IC(50) values of 3.4 and 4.5 µM, respectively. RB19 comprises a rigid core scaffold and a flexible chain with a large polar moiety. The former interacts with highly conserved residues, decreasing the probability of resistance. The latter forms van der Waals contacts with the WT subsite and yields hydrogen bonds with the mutant subsite by switching the orientation of its flexible side chain. Both scaffolds of RB19 are good starting points for lead optimization. The results reveal a parallel screening strategy for identifying resistance mechanisms and discovering anti-resistance neuraminidase inhibitors. We believe that this strategy may be applied to other diseases with high mutation rates, such as cancer and human immunodeficiency virus type 1. HubMed – drug