title: Inhibition of TDP-43 accumulation by bis(thiosemicarbazonato)-copper complexes.
abstract: Amyotrophic lateral sclerosis (ALS) is a progressive, fatal, motor neuron disease with no effective long-term treatment options. Recently, TDP-43 has been identified as a key protein in the pathogenesis of some cases of ALS. Although the role of TDP-43 in motor neuron degeneration is not yet known, TDP-43 has been shown to accumulate in RNA stress granules (SGs) in cell models and in spinal cord tissue from ALS patients. The SG association may be an early pathological change to TDP-43 metabolism and as such a potential target for therapeutic intervention. Accumulation of TDP-43 in SGs induced by inhibition of mitochondrial activity can be inhibited by modulation of cellular kinase activity. We have also found that treatment of cells and animal models of neurodegeneration, including an ALS model, with bioavailable bis(thiosemicarbazonato)copper(II) complexes (Cu(II)(btsc)s) can modulate kinase activity and induce neuroprotective effects. In this study we examined the effect of diacetylbis(-methylthiosemicarbazonato)copper(II) (Cu(II)(atsm)) and glyoxalbis(-methylthiosemicarbazonato)copper(II) (Cu(II)(gtsm)) on TDP-43-positive SGs induced in SH-SY5Y cells in culture. We found that the Cu(II)(btsc)s blocked formation of TDP-43-and human antigen R (HuR)-positive SGs induced by paraquat. The Cu(II)(btsc)s protected neurons from paraquat-mediated cell death. These effects were associated with inhibition of ERK phosphorylation. Co-treatment of cultures with either Cu(II)(atsm) or an ERK inhibitor, PD98059 both prevented ERK activation and blocked formation of TDP-43-and HuR-positive SGs. Cu(II)(atsm) treatment or ERK inhibition also prevented abnormal ubiquitin accumulation in paraquat-treated cells suggesting a link between prolonged ERK activation and abnormal ubiquitin metabolism in paraquat stress and inhibition by Cu. Moreover, Cu(II)(atsm) reduced accumulation of C-terminal (219-414) TDP-43 in transfected SH-SY5Y cells. These results demonstrate that Cu(II)(btsc) complexes could potentially be developed as a neuroprotective agent to modulate neuronal kinase function and inhibit TDP-43 aggregation. Further studies in TDP-43 animal models are warranted.
authors.affiliation: Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Parker
authors.forename: Jodi
authors.initials: J
authors.lastname: Meyerowitz
authors.forename: Janine L
authors.initials: JL
authors.lastname: James
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Liddell
authors.forename: Takashi
authors.initials: T
authors.lastname: Nonaka
authors.forename: Masato
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Katja M
authors.initials: KM
authors.lastname: Kanninen
authors.forename: SinChun
authors.initials: S
authors.lastname: Lim
authors.forename: Brett M
authors.initials: BM
authors.lastname: Paterson
authors.forename: Paul S
authors.initials: PS
authors.lastname: Donnelly
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Crouch
authors.forename: Anthony R
authors.initials: AR
authors.lastname: White
mesh_terms: D056831:Coordination Complexes / Q000494:pharmacology*; D003300:Copper / Q000494:pharmacology*; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051959:ELAV Proteins / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology; D009498:Neurotoxins / Q000633:toxicity; D010269:Paraquat / Q000633:toxicity; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D020836:Protein Structure, Quaternary; D021381:Protein Transport / Q000187:drug effects; D013882:Thiosemicarbazones / Q000494:pharmacology*; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D056831:Coordination Complexes; D004268:DNA-Binding Proteins; D051959:ELAV Proteins; D018696:Neuroprotective Agents; D009498:Neurotoxins; D047428:Protein Kinase Inhibitors; D013882:Thiosemicarbazones; D025801:Ubiquitin; D003300:Copper; D048049:Extracellular Signal-Regulated MAP Kinases; D010269:Paraquat