A Daphnane Diterpenoid Isolated from Wikstroemia polyantha Induces an Inflammatory Response and Modulates miRNA Activity

MicroRNAs (miRNAs) are endogenously expressed single-stranded ∼21–23 nucleotide RNAs that inhibit gene expression post-transcriptionally by binding imperfectly to elements usually within the 3′untranslated region (3′UTR) of mRNAs. Small interfering RNAs (siRNAs) mediate site-specific cleavage by binding with perfect complementarity to RNA. Here, a cell-based miRNA reporter system was developed to screen for compounds from marine and plant extracts that inhibit miRNA or siRNA activity. The daphnane diterpenoid genkwanine M (GENK) isolated from the plant Wikstroemia polyantha induces an early inflammatory response and can moderately inhibit miR-122 activity in the liver Huh-7 cell line. GENK does not alter miR-122 levels nor does it directly inhibit siRNA activity in an in vitro cleavage assay. Finally, we demonstrate that GENK can inhibit HCV infection in Huh-7 cells. In summary, the development of the cell-based miRNA sensor system should prove useful in identifying compounds that affect miRNA/siRNA activity

The presence of oligoclonal IgG bands in human CSF during the course of neurological diseases

The analysis of cerebrospinal fluid (CSF) is an important tool for the diagnosis of neurological diseases. However, there is limited knowledge about the representativity of a single oligoclonal band (OCB) analysis for a neurological disease during its clinical course. In this study, we analyzed the presence of OCB in the CSF of patients who underwent lumbar puncture more than once. We retrospectively analyzed anonymized data from serial 17,002 CSF analyses done in the CSF laboratory of the Department of Neurology, University Hospital Zurich. We included cases with documented diagnosis in whom OCB were determined more than once. We included 144 patients. The median time span between the first and second OCB analysis was 274 days (range, 1-3,533 days). The result of the second OCB analysis was identical in 109 cases, and different in 35 (24 %). Twenty-five patients acquired and ten patients lost OCB over time. Three of 24 MS patients did not show OCB at the first CSF analysis, but in the second. In the entire group, newly occurring OCB were often associated with new symptoms or occurred after the acute phase of CNS infectious diseases, supposedly as a consequence of the immune reaction. A loss of OCB was often associated with remissions from diseases, e.g., during effective treatment. In patients with neurological diseases, both initially positive and negative OCB results may change over time, which often parallels the clinical condition. Such variability must be taken into account for the interpretation of OCB results

An intronic mutation in MLH1 associated with familial colon and breast cancer

Single base substitutions can lead to missense mutations, silent mutations or intronic mutations, whose significance is uncertain. Aberrant splicing can occur due to mutations that disrupt or create canonical splice sites or splicing regulatory sequences. The assessment of their pathogenic role may be difficult, and is further complicated by the phenomenon of alternative splicing. We describe an HNPCC patient, with early-onset colorectal cancer and a strong family history of colorectal and breast tumors, who harbours a germ line MLH1 intronic variant (IVS9 c.790 +4A>T). The proband, together with 2 relatives affected by colorectal-cancer and 1 by breast cancer, have been investigated for microsatellite instability, immunohistochemical MMR protein staining, direct sequencing and Multiplex Ligation-dependent Probe Amplification. The effect of the intronic variant was analyzed both by splicing prediction software and by hybrid minigene splicing assay. In this family, we found a novel MLH1 germline intronic variant (IVS9 c.790 +4A>T) in intron 9, consisting of an A to T transversion, in position +4 of the splice donor site of MLH1. The mutation is associated with the lack of expression of the MLH1 protein and MSI in tumour tissues. Furthermore, our results suggest that this substitution leads to a complete skip of both exon 9 and 10 of the mutant allele. Our findings suggest that this intronic variant plays a pathogenic rol

A gammaherpesvirus provides protection against allergic asthma by inducing the replacement of resident alveolar macrophages with regulatory monocytes.

The hygiene hypothesis postulates that the recent increase in allergic diseases such as asthma and hay fever observed in Western countries is linked to reduced exposure to childhood infections. Here we investigated how infection with a gammaherpesvirus affected the subsequent development of allergic asthma. We found that murid herpesvirus 4 (MuHV-4) inhibited the development of house dust mite (HDM)-induced experimental asthma by modulating lung innate immune cells. Specifically, infection with MuHV-4 caused the replacement of resident alveolar macrophages (AMs) by monocytes with regulatory functions. Monocyte-derived AMs blocked the ability of dendritic cells to trigger a HDM-specific response by the TH2 subset of helper T cells. Our results indicate that replacement of embryonic AMs by regulatory monocytes is a major mechanism underlying the long-term training of lung immunity after infection