Familial CHARGE syndrome and the CHD7 gene: a recurrent missense mutation, intrafamilial recurrence and variability

CHARGE syndrome is an autosomal dominant condition that is caused by mutations in the CHD7 gene. Few familial cases of this syndrome have been reported and these were characterized by a wide clinical variability. We here report on five CHD7 mutation positive families and comment on their clinical features. We observed somatic and germline mosaicism as well as parent-to-child transmission of non-mosaic CHD7 mutations as causes of familial CHARGE syndrome. In one family with two affected sibs a somatic mutation was identified in lymphocytes of a clinically unaffected parent (2520G > A in exon 8). This is the second report of somatic CHD7 mosaicism in an unaffected parent. In two further families with affected siblings, we could not detect the mutation in parental lymphocytes suggesting germline mosaicism. The previously reported clinical variability was strikingly present in all five families. We find that alterations in CHD7 can result in a very mild phenotype, characterized by only a few minor symptoms of the CHARGE syndrome clinical spectrum. Such a mild phenotype was present in two families that shared the same 6322G > A missense mutation. These two families showed parent-to-child transmission. Phenotypically milder forms of CHARGE syndrome have a higher risk of transmission to multiple family members.     

R1467H variant in the rho guanine nucleotide exchange factor 11 (<Emphasis Type="Italic">ARHGEF11</Emphasis>) is associated with impaired glucose tolerance and type 2 diabetes in German Caucasians

The human rho guanine nucleotide exchange factor 11 (ARHGEF11) functions as an activator of rho GTPases and is supposed to influence insulin signalling. We investigated the effects of the previously reported R1467H variant in individual’s susceptibility to type 2 diabetes (T2D) and impaired glucose tolerance (IGT) as well as related traits in a German Caucasian cohort. Our study replicated associations of the R1467H with increased risk of T2D or T2D/IGT, thus, implicating a potential role of ARHGEF11 in the aetiology of T2D and IGT.     

The identification of a small molecule inhibitor that specifically reduces T cell-mediated adaptive but not LPS-mediated innate immunity by T cell membrane-monocyte contact bioassay

Proinflammatory cytokines such as TNFalpha and IL-1beta are produced in lesional skin of chronic plaque psoriasis patients, and at other sites of chronic inflammation such as arthritic joints. They play vital roles in maintaining inflammation. It has recently been suggested that activated T cell contact-mediated monocyte activation, leading to the production of proinflammatory cytokines, contributes to the pathogenesis of psoriasis and other chronic inflammatory diseases such as psoriatic arthritis and rheumatoid arthritis. Using a T cell membrane-monocyte contact bioassay, we have identified small molecule antagonists that differentially block anti-CD3/anti-CD28 activated T cell-mediated, but not LPS-stimulated, TNFalpha production from monocytes. We selected several kinase inhibitors from the Berlex/Schering kinase library and tested the effect of these compounds in blocking TNFalpha production in the T cell membrane-monocyte contact bioassay. We have demonstrated that one compound BLX-1, from a p38 MAP kinase inhibitor project, inhibited T cell-mediated TNFalpha production from monocytes by about 80%, without any effect on TNFalpha production from LPS-stimulated monocytes. Other BLX-1 analogs showed 32-83% inhibition of TNFalpha production with LPS stimulation as compared to almost 100% inhibition of T cell-mediated TNFalpha production. In contrast, PKC inhibitors BLX-5, Go6983, and Ro-31-8220, inhibited TNFalpha production from both activated T cell membrane- and LPS-stimulated monocytes to the same extent (in the range of 50-100% inhibition). Therefore, the activated T cell membrane-monocyte contact bioassay can be used to screen small molecule antagonists that specifically target adaptive but not LPS-mediated innate immunity. Small molecule TNFalpha inhibitors interfering specifically with activated T cell contact-mediated TNFalpha production from monocytes, but not with LPS-mediated TNFalpha production of myeloid cells, are predicted to have an improved side-effect profile and thus may provide more favorable therapeutics for the treatment of T cell-mediated inflammatory diseases.     

Capture of cell culture-derived influenza virus by lectins: strain independent, but host cell dependent

Strategies to control influenza outbreaks are focused mainly on prophylactic vaccination. Human influenza vaccines are trivalent blends of different virus subtypes. Therefore and due to frequent antigenic drifts, strain independent manufacturing processes are required for vaccine production. This study verifies the strain independency of a capture method based on Euonymus europaeus lectin-affinity chromatography (EEL-AC) for downstream processing of influenza viruses under various culture conditions propagated in MDCK cells. A comprehensive lectin binding screening was conducted for two influenza virus types from the season 2007/2008 (A/Wisconsin/67/2005, B/Malaysia/2506/2004) including a comparison of virus-lectin interaction by surface plasmon resonance technology. EEL-AC resulted in a reproducible high product recovery rate and a high degree of contaminant removal in the case of both MDCK cell-derived influenza virus types demonstrating clearly the general applicability of EEL-AC. In addition, host cell dependency of EEL-AC was studied with two industrial relevant cell lines: Vero and MDCK cells. However, the choice of the host cell lines is known to lead to different product glycosylation profiles. Hence, altered lectin specificities have been observed between the two cell lines, requiring process adaptations between different influenza vaccine production systems.     

The secretome of the filarial parasite, Brugia malayi: proteomic profile of adult excretory-secretory products

The secretome of a parasite in its definitive host can be considered to be its genome in trans, to the extent that secreted products encoded by the parasite fulfill their function in the host milieu. The 'extended phenotype' of the filarial parasite, Brugia malayi, is of particular interest because of the evidence that infection results in potent down-modulation of the host immune response. We collected B. malayi 'excretory-secretory' (BES) proteins from adult parasites and using a combination of shotgun LC-MS/MS and 2D gel electrophoresis, identified 80 B. malayi and two host proteins in BES, of which 31 (38%) were detectable in whole worm extract (BmA). Products which were enriched in BES relative to BmA included phosphatidylethanolamine-binding protein (PEB), leucyl aminopeptidase (LAP, homologue of ES-62 from the related filaria Acanthocheilonema viteae), N-acetylglucosaminyltransferase (GlcNAcT) and galectin-1, in addition to the previously described major surface glycoprotein, glutathione peroxidase (gp29, GPX-1) and the cytokine homologue macrophage migration inhibitory factor (MIF-1). One of the most abundant released proteins was triose phosphate isomerase (TPI), yet many other glycolytic enzymes (such as aldolase and GAPDH) were found only in the somatic extract. Among the more prominent novel products identified in BES were a set of 11 small transthyretin-like proteins, and three glutamine-rich-repeat mucin-like proteins. Notably, no evidence was found of any secreted protein corresponding to the genome of the Wolbachia endosymbiont present in B. malayi. Western blotting with anti-phosphorylcholine (PC) monoclonal antibody identified that GlcNAcT, and not the ES-62 homologue, is the major PC-bearing protein in BES, while probing with human filariasis sera showed preferential reactivity to galectin-1 and to processed forms of myotactin. Overall, this analysis demonstrates selective release of a suite of newly identified proteins not previously suspected to be involved at the host-parasite interface, and provides important new perspectives on the biology of the filarial parasite.