The Sesquiterpenes Polygodial and Drimanial in vitro Affect Glutamatergic Transport in Rat Brain

Natural products including those derived from plants, have over the years greatly contributed to the development of therapeutic drugs. Polygodial and drimanial are sesquiterpenes isolated from the bark of the plant Drymis Winteri (Winteraceae) that exhibit antinociceptive properties. Since peripheral glutamate presents nociceptive actions, in this study it was investigated the effects of hydroalcooholic extracts from Drymis winteri (polygodial and drimanial) on the glutamatergic system in rat brain. Polygodial and drimanial inhibited glutamate uptake by astrocytes, as well as by cortical, hippocampal and striatal slices, and increased synaptosomal glutamate release. These concurrent effects would predispose to an increase in the extracellular glutamate concentrations, leading to possible neurotoxic effects (excitotoxicity) of these natural compounds, which would suggest the need for some caution in their therapeutic application.     

Episodic encoding is more than the sum of its parts: an fMRI investigation of multifeatural contextual encoding

Episodic memories are characterized by their contextual richness, yet little is known about how the various features comprising an episode are brought together in memory. Here we employed fMRI and a multidimensional source memory procedure to investigate processes supporting the mnemonic binding of item and contextual information. Volunteers were scanned while encoding items for which the contextual features (color and location) varied independently, allowing activity elicited at the time of study to be segregated according to whether both, one, or neither feature was successfully retrieved on a later memory test. Activity uniquely associated with successful encoding of both features was identified in the intra-parietal sulcus, a region strongly implicated in the support of attentionally mediated perceptual binding. The findings suggest that the encoding of disparate features of an episode into a common memory representation requires that the features be conjoined in a common perceptual representation when the episode is initially experienced.     

Antiviral and regulatory T cell immunity in a patient with stromal interaction molecule 1 deficiency

Stromal interaction molecule 1 (STIM1) deficiency is a rare genetic disorder of store-operated calcium entry, associated with a complex syndrome including immunodeficiency and immune dysregulation. The link from the molecular defect to these clinical manifestations is incompletely understood. We report two patients with a homozygous R429C point mutation in STIM1 completely abolishing store-operated calcium entry in T cells. Immunological analysis of one patient revealed that despite the expected defect of T cell proliferation and cytokine production in vitro, significant antiviral T cell populations were generated in vivo. These T cells proliferated in response to viral Ags and showed normal antiviral cytotoxicity. However, antiviral immunity was insufficient to prevent chronic CMV and EBV infections with a possible contribution of impaired NK cell function and a lack of NKT cells. Furthermore, autoimmune cytopenia, eczema, and intermittent diarrhea suggested impaired immune regulation. FOXP3-positive regulatory T (Treg) cells were present but showed an abnormal phenotype. The suppressive function of STIM1-deficient Treg cells in vitro, however, was normal. Given these partial defects in cytotoxic and Treg cell function, impairment of other immune cell populations probably contributes more to the pathogenesis of immunodeficiency and autoimmunity in STIM1 deficiency than previously appreciated.     

Phosphonium lipocations as antiparasitic agents

Phosphonium lipocations were synthesized and evaluated for inhibition of the development of Plasmodium falciparum and Trypanosoma cruzi, etiological agents of malaria and Chagas disease, respectively. Optimal phthalimides and 1,4-naphthoquinone-based lipocations were active in vitro at mid-high nM concentrations against P. falciparum and low μM concentrations against T. cruzi.     

Concomitant targeting of EGF receptor, TGF-beta and SRC points to a novel therapeutic approach in pancreatic cancer

To test the hypothesis that concomitant targeting of the epidermal growth factor receptor (EGFR) and transforming growth factor-beta (TGF-β) may offer a novel therapeutic approach in pancreatic cancer, EGFR silencing by RNA interference (shEGFR) was combined with TGF-β sequestration by soluble TGF-β receptor II (sTβRII). Effects on colony formation in 3-dimensional culture, tumor formation in nude mice, and downstream signaling were monitored. In both ASPC-1 and T3M4 cells, either shEGFR or sTβRII significantly inhibited colony formation. However, in ASPC-1 cells, combining shEGFR with sTβRII reduced colony formation more efficiently than either approach alone, whereas in T3M4 cells, shEGFR-mediated inhibition of colony formation was reversed by sTβRII. Similarly, in vivo growth of ASPC-1-derived tumors was attenuated by either shEGFR or sTβRII, and was markedly suppressed by both vectors. By contrast, T3M4-derived tumors either failed to form or were very small when EGFR alone was silenced, and these effects were reversed by sTβRII due to increased cancer cell proliferation. The combination of shEGFR and sTβRII decreased phospho-HER2, phospho-HER3, phoshpo-ERK and phospho-src (Tyr416) levels in ASPC-1 cells but increased their levels in T3M4 cells. Moreover, inhibition of both EGFR and HER2 by lapatinib or of src by SSKI-606, PP2, or dasatinib, blocked the sTβRII-mediated antagonism of colony formation in T3M4 cells. Together, these observations suggest that concomitantly targeting EGFR, TGF-β, and src may constitute a novel therapeutic approach in PDAC that prevents deleterious cross-talk between EGFR family members and TGF-β-dependent pathways.     

Normal adult climbing fiber monoinnervation of cerebellar Purkinje cells in mice lacking MHC class I molecules

Some immune system proteins have recently been implicated in the development and plasticity of neuronal connections. Notably, proteins of the major histocompatibility complex 1 (MHC class 1) have been shown to be involved in synaptic plasticity in the hippocampus and the development of projection patterns in the visual system. We examined the possible role for the MHC class 1 proteins in one well-characterized example of synaptic exuberance and subsequent refinement, the climbing fiber (CF) to Purkinje cell (PC) synapse. Cerebella from adult mice deficient for two MHC genes, H2-D1 and H2-K1, and for beta2-microglobulin gene were examined for evidence of deficient elimination of supernumerary CF synapses on their PCs. Electrophysiological and morphological evidence showed that, despite the absence of these MHC class 1 molecules, adult PCs in these transgenic mice are monoinnervated as in wild-type animals. These findings indicate that, at the level of restriction of afferent number at this synapse, functional MHC class 1 proteins are not required.     

Novel insights into the genetic background of genetically modified mice

Unclear or misclassified genetic background of laboratory rodents or a lack of strain awareness causes a number of difficulties in performing or reproducing scientific experiments. Until now, genetic differentiation between strains and substrains of inbred mice has been a challenge. We have developed a screening method for analyzing inbred strains regarding their genetic background. It is based on 240 highly informative short tandem repeat (STR) markers covering the 19 autosomes as well as X and Y chromosomes. Combination of analysis results for presence of known C57BL/6 substrain-specific mutations together with autosomal STR markers and the Y-chromosomal STR-haplotype provides a comprehensive snapshot of the genetic background of mice. In this study, the genetic background of 72 mouse lines obtained from 18 scientific institutions in Germany and Austria was determined. By analyzing only 3 individuals per genetically modified line it was possible to detect mixed genetic backgrounds frequently. In several lines presence of a mispairing Y chromosome was detected. At least every second genetically modified line displayed a mixed genetic background which could lead to unexpected and non-reproducible results, irrespective of the investigated gene of interest.