The pesticides tebufenpyrad and pyridaben are lipophilic in character and are hence dissolved in DMSO. capacity. The luminescence-based ATP measurement further confirmed that pesticide-induced mitochondrial inhibition of respiration is accompanied by the loss of cellular ATP. Collectively, our results suggest that exposure to the pesticides Mouse monoclonal antibody to PRMT6. PRMT6 is a protein arginine N-methyltransferase, and catalyzes the sequential transfer of amethyl group from S-adenosyl-L-methionine to the side chain nitrogens of arginine residueswithin proteins to form methylated arginine derivatives and S-adenosyl-L-homocysteine. Proteinarginine methylation is a prevalent post-translational modification in eukaryotic cells that hasbeen implicated in signal transduction, the metabolism of nascent pre-RNA, and thetranscriptional activation processes. IPRMT6 is functionally distinct from two previouslycharacterized type I enzymes, PRMT1 and PRMT4. In addition, PRMT6 displaysautomethylation activity; it is the first PRMT to do so. PRMT6 has been shown to act as arestriction factor for HIV replication tebufenpyrad and pyridaben induces neurotoxicity by rapidly initiating mitochondrial dysfunction and oxidative damage in dopaminergic neuronal cells. Our findings also reveal that monitoring the kinetics of mitochondrial respiration with Seahorse could be used as an early neurotoxicological high-throughput index for assessing the risk that pesticides pose to the dopaminergic neuronal system. oxidative phosphorylation (Chan, 2006, Hoppins et al., 2007, Jin et al., 2014a, Zhang and Chan, 2007). Some of the critical biochemical abnormalities resulting from mitochondrial dysfunction are increased generation of reactive oxygen species (ROS), loss of ATP production during cellular respiration and impaired Ca2+ ion channels (Schapira, 2007, Winklhofer and Haass, 2010). Neurotoxic stress also induces structural damage to mitochondria including mitochondrial fragmentation and mitophagy (Lin et al., 2012, Lin and Beal, 2006). Tebufenpyrad (IUPAC name: N-[(4-tert-butylphenyl)methyl]-4-chloro-5-ethyl-2-methylpyrazole-3-carboxamide) and pyridaben (IUPAC name: 2-tert-butyl-5-[(4-tert-butylphenyl)methylsulfanyl]-4-chloropyridazin-3-one) are common acaricides used to kill populations of mites and ticks in commercial greenhouses. Tebufenpyrad is chemically classified as a pyrazole carboxyamide, which is registered for use in HDAC-IN-7 greenhouses for the protection of ornamental plants (EPA PC Code- 090102). Pyridaben is chemically classified as a pyridazinone, whose major application is in greenhouses and vineyards (EPA PC Code- 129105). Similar to rotenone, tebufenpyrad and pyridaben have been shown to function as mitochondrial complex I inhibitors (classified by the IRAC-Insecticide Resistance Action Committee – http://www.irac-online.org/modes-of-action/). Although their intended mode of action and target toxicity are similar to those of rotenone, both tebufenpyrad and pyridaben have not been studied in detail with respect to their neurotoxicity. Therefore, in this study, we evaluated the neurotoxic effects of tebufenpyrad and pyridaben in rat dopaminergic neuronal cells, with particular emphasis on their effects on mitochondrial dynamics and their roles in dopaminergic neuronal cell death. 2. Materials and HDAC-IN-7 Methods 2.1 Chemicals We purchased tebufenpyrad (96% purity) from AK Scientific Inc. (Union City, CA), pyridaben (99.1% purity) from Chem Services (West Chester, PA), and rotenone (95C98% purity) and hydrogen peroxide (30 wt. % in H2O) from Sigma (St. Louis, MO). DMSO was purchased from Fisher Scientific (Fair Law, NJ). We purchased RPMI 1640 media, fetal bovine serum (FBS), L-glutamine, penicillin, streptomycin and Sytox green nucleic acid fluorescence stain from Molecular Probes (Eugene, OR), the Muse? Count & Viability Assay Kit (Catalog # MCH100102) from EMD Millipore (Billerica, MA), and the 5-(and-6)-chloromethyl-2,7-dichlorodihydrofluorescein diacetate (CM-H2DCFDA) fluorescent probe and MitoTracker red CMXROS and MitoTracker green dyes from Invitrogen (Carlsbad, CA). The Cell Titer 96? AQueous Non-Radioactive Cell Proliferation HDAC-IN-7 assay kit and Cell Titer Glo Luminescent Cell Viability assay kit were bought from Promega (Madison, WI). The Aconitase assay kit was purchased from Abcam (Cambridge, MA). Oligomycin, hydrogen peroxide, carbonyl cyanide 4-trifluoromethoxy-phenylhydrazone HDAC-IN-7 (FCCP) and antimycin A were purchased from Sigma Aldrich (St. Louis, MO), and the Seahorse FluxPak calibration solution was bought from Seahorse Biosciences (Billerica, MA). 2.2 Cell culture and treatment paradigm The rat immortalized mesencephalic dopaminergic neuronal cell line (1RB3AN27, also known as N27 cells) was a kind gift from Dr. Kedar N. Prasad (University of Colorado Health Sciences Center, Denver, CO). These N27 cells have the potential to differentiate and produce dopamine in culture when exposed to a suitable cAMP triggering agent, and once the cells are differentiated they possess increased tyrosine hydroxylase (TH) expression and dopamine levels (Adams et al., 1996, Zhang et al., 2007). In this study, undifferentiated cells were grown in RPMI 1640 medium containing 10% FBS, 2 mM L-glutamine, 50 units of penicillin, and 50.