Notiz zum Vorkommen der Carex arenaria L. (Sandsegge) bei Düsseldorf

von Kurt Rehnelt, Düsseldor

Overexpression of Tumor Necrosis Factor Alpha by a Recombinant Rabies Virus Attenuates Replication in Neurons and Prevents Lethal Infection in Mice

The effect of tumor necrosis factor alpha (TNF-α) on rabies virus (RV) infection of the mouse central nervous system (CNS) was studied, using recombinant RV engineered to express either soluble TNF-α [SPBN-TNF-α(+)] or insoluble membrane-bound TNF-α [SPBN-TNF-α(MEM)]. Growth curves derived from infections of mouse neuroblastoma NA cells revealed significantly less spread and production of SPBN-TNF-α(+) than of SPBN-TNF-α(MEM) or SPBN-TNF-α(−), which carries an inactivated TNF-α gene. The expression of soluble or membrane-bound TNF-α was not associated with increased cell death or induction of alpha/beta interferons. Brains of mice infected intranasally with SPBN-TNF-α(+) showed significantly less virus spread than did mouse brains after SPBN-TNF-α(−) infection, and none of the SPBN-TNF-α(+)-infected mice succumbed to RV infection, whereas 80% of SPBN-TNF-α(−)-infected mice died. Reduced virus spread in SPBN-TNF-α(+)-infected mouse brains was paralleled by enhanced CNS inflammation, including T-cell infiltration and microglial activation. These data suggest that TNF-α exerts its protective activity in the brain directly through an as yet unknown antiviral mechanism and indirectly through the induction of inflammatory processes in the CNS

Frequency-Dependent Multi-Well Cardiotoxicity Screening Enabled by Optogenetic Stimulation

Side effects on cardiac ion channels causing lethal arrhythmias are one major reason for drug withdrawals from the market. Field potential (FP) recording from cardiomyocytes, is a well-suited tool to assess such cardiotoxic effects of drug candidates in preclinical drug development, but it is currently limited to the spontaneous beating of the cardiomyocytes and manual analysis. Herein, we present a novel optogenetic cardiotoxicity screening system suited for the parallel automated frequency-dependent analysis of drug effects on FP recorded from human-induced pluripotent stem cell-derived cardiomyocytes. For the expression of the light-sensitive cation channel Channelrhodopsin-2, we optimised protocols using virus transduction or transient mRNA transfection. Optical stimulation was performed with a new light-emitting diode lid for a 96-well FP recording system. This enabled reliable pacing at physiologically relevant heart rates and robust recording of FP. Thereby we detected rate-dependent effects of drugs on Na+, Ca2+ and K+ channel function indicated by FP prolongation, FP shortening and the slowing of the FP downstroke component, as well as generation of afterdepolarisations. Taken together, we present a scalable approach for preclinical frequency-dependent screening of drug effects on cardiac electrophysiology. Importantly, we show that the recording and analysis can be fully automated and the technology is readily available using commercial products