Emamectin is a non-selective allosteric activator of nicotinic acetylcholine receptors and GABAA/C receptors

Molecular and Functional Characterization of Different BrainSphere Models for Use in Neurotoxicity Testing on Microelectrode Arrays

The currently accepted methods for neurotoxicity (NT) testing rely on animal studies. However, high costs and low testing throughput hinder their application for large numbers of chemicals. To overcome these limitations, in vitro methods are currently being developed based on human-induced pluripotent stem cells (hiPSC) that allow higher testing throughput at lower costs. We applied six different protocols to generate 3D BrainSphere models for acute NT evaluation. These include three different media for 2D neural induction and two media for subsequent 3D differentiation resulting in self-organized, organotypic neuron/astrocyte microtissues. All induction protocols yielded nearly 100% NESTIN-positive hiPSC-derived neural progenitor cells (hiNPCs), though with different gene expression profiles concerning regional patterning. Moreover, gene expression and immunocytochemistry analyses revealed that the choice of media determines neural differentiation patterns. On the functional level, BrainSpheres exhibited different levels of electrical activity on microelectrode arrays (MEA). Spike sorting allowed BrainSphere functional characterization with the mixed cultures consisting of GABAergic, glutamatergic, dopaminergic, serotonergic, and cholinergic neurons. A test method for acute NT testing, the human multi-neurotransmitter receptor (hMNR) assay, was proposed to apply such MEA-based spike sorting. These models are promising tools not only in toxicology but also for drug development and disease modeling.

Phenotypic Profiling of Macrocyclic Lactones on Parasitic Schistosoma Flatworms

Macrocyclic lactones are front-line therapies for parasitic roundworm infections; however, there are no comprehensive studies on the activity of this drug class against parasitic flatworms. Ivermectin is well known to be inactive against flatworms. However, the structure-activity relationship of macrocyclic lactones may vary across phyla, and it is entirely possible other members of this drug class do in fact show antiparasitic activity on flatworms. For example, there are several reports hinting at the anti-schistosomal activity of doramectin and moxidectin. To explore this class further, we developed an automated imaging assay combined with measurement of lactate levels from worm media. This assay was applied to the screening of 21 macrocyclic lactones (avermectins, milbemycins, and others such as spinosyns) against adult schistosomes. These in vitro assays identified several macrocyclic lactones (emamectin, milbemycin oxime, and the moxidectin metabolite 23-ketonemadectin) that caused contractile paralysis and lack of lactate production. Several of these were also active against miracidia, which infect the snail intermediate host. Hits prioritized from these in vitro assays were administered to mice harboring patent schistosome infections. However, no reduction in worm burden was observed. Nevertheless, these data show the utility of a multiplexed in vitro screening platform to quantitatively assess drug action and exclude inactive compounds from a chemical series before proceeding to in vivo studies. While the prototypical macrocyclic lactone ivermectin displays minimal activity against adult Schistosoma mansoni, this family of compounds does contain schistocidal compounds which may serve as a starting point for development of new anti-flatworm chemotherapies.

ToxCast chemical library Wnt screen identifies diethanolamine as an activator of neural progenitor proliferation

Numerous autism spectrum disorder (ASD) risk genes are associated with Wnt signaling, suggesting that brain development may be especially sensitive to genetic perturbation of this pathway. Additionally, valproic acid, which modulates Wnt signaling, increases risk for ASD when taken during pregnancy. We previously found that an autism-linked gain-of-function UBE3A T485A mutant construct hyperactivated canonical Wnt signaling, providing a genetic means to elevate Wnt signaling above baseline levels. To identify environmental use chemicals that enhance or suppress Wnt signaling, we screened the ToxCast Phase I and II libraries in cells expressing this autism-linked UBE3A T485A gain-of-function mutant construct. Using structural comparisons, we identify classes of chemicals that stimulated Wnt signaling, including ethanolamines, as well as chemicals that inhibited Wnt signaling, such as agricultural pesticides, and synthetic hormone analogs. To prioritize chemicals for follow-up, we leveraged predicted human exposure data, and identified diethanolamine (DEA) as a chemical that stimulates Wnt signaling in UBE3A T485A -transfected cells, and has a high potential for prenatal exposure in humans. DEA enhanced proliferation in primary human neural progenitor cell lines (phNPC), but did not affect expression of canonical Wnt target genes in NPCs or primary mouse neuron cultures. Instead, we found DEA increased expression of the H3K9 methylation sensitive gene CALB1, consistent with competitive inhibition of the methyl donor enzymatic pathways.

Combined effect of furanone fluconazole and amphotericin B against biofilms formed from Cryptococcus neoformans

It is of interest to document the combined effect of furanone fluconazole and amphotericin B against the biofilm formed by Cryptococcus neoformans. The MIC values of amphotericine B and Fluconazole were observed as 20µg/ml and 60µg/ml, respectively. The MIC for the Combination (Amphotericin B/ Fluconazole) was found to be at (15/20) µg/ml drug concentration. Thus, data shows the combined effect of furanone fluconazole and amphotericine B derivative against C. neoformans.

Sub-lethal doses of Nucleopolyhedrosis Virus and synthetic ınsecticides alter the biological parameters of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

Resistance management is very important for devising control strategies of polyphagous insect-pests like Helicoverpa armigera Hübner (Lepidoptera: Noctuidae). Considering the importance of resistance management, demographic features of selected and unselected populations of H. armigera were studied in 6 different treatments viz. emamectin benzoate, Helicoverpa armigera Nucleopolyhedrosis Virus (HaNPV), emamectin benzoate+HaNPV, spinetoram, spinetoram+HaNPV and control. Higher values for fecundity, intrinsic rate, the finite rate of increase (λ) were recorded in the control of selected as compared to the rest of treatment. Similarly, higher values for these population parameters viz. oviposition days, fecundity, intrinsic rate, the finite rate of increase were calculated in the unselected control. Similarly, net reproductive rate (R₀) for selected and unselected control was higher as compared to the rest of the treatments. It may happen because these kinds of selection pressures can result in decreased fitness of the test insect thus decreased fitness of H. armigera in different treatments was observed as compared to the control. Additionally, quicker development of susceptible insects was observed because susceptible insects were growing without any stressor (xenobiotics) as compared to the rest which contributed to their faster development.

Interaction of HaNPVs with two novel insecticides against Helicoverpa armigera Hubner (Noctuidae: Lepidoptera)

Nucleopolyhedrosis viruses can be utilized for effective management of agriculture pests. Their efficacy can be increased if they are mixed with certain insecticides. In the current study, HaNPV was mixed with two insecticides: spinetoram and emamectin benzoate in various combinations and applied to larvae of H. armigera in laboratory conditions. There were a total of 15 combinations of HaNPV with each of the two insecticides in addition to five doses of HaNPV and three doses of insecticides alone. The synergistic and antagonistic effects of combinations were explored. The results revealed that there was synergistic effect of HaNPV @ 0.5 × 10⁹ PIB/ml × Spinetoram @ 40, 20, 10 ml/100 L of water. In case of emamectin benzoate, synergistic effects were recorded at 1 × 10⁹ PIB/ml HaNPV × emamectin benzoate @ 100 ml/100 L of water. However, 0.5 × 10⁹ PIB/ml HaNPV has synergistic effects with all three doses of emamectin benzoate. The results suggested that HaNPV can be used in combination with spinetoram and emamectin benzoate for the management of resistant population of H. armigera.

Molecular docking analysis of timepidium with Acetylcholine and lumacaftor with GABA(A) activator

Epilepsy is a chronic disorder characterized by disturbed tissue related molecular activity within the brain irrespective of age. The cause is very difficult to understand towards a suitable treatment. However, its symptoms like seizures are treated and suppressed by known medications. Moreover, the condition is linked with neuro-transmitters such as GABA (gamma amino butyric acid) and acetylcholine. Therefore, it is of interest to design and develop inhibitors for these targets. Hence, we describe the molecular binding features of timepidium with acetylcholine and lumacaftor with GABA(A) activator using molecular docking based geometric optimization and screening analysis for further consideration.