title: The natural scorpion peptide, BmK NT1 activates voltage-gated sodium channels and produces neurotoxicity in primary cultured cerebellar granule cells.
abstract: The scorpion Buthus martensii Karsch has been used in Traditional Chinese Medicine to treat neuronal diseases such as neuropathic pain, paralysis and epilepsy for thousands of years. Studies have demonstrated that scorpion venom is the primary active component. Although scorpion venom can effectively attenuate pain in the clinic, it also produces neurotoxic response. In this study, toxicity guided purification led to identify a mammalian toxin termed BmK NT1 comprising of 65 amino acid residues and an amidated C-terminus, a mature peptide encoded by the nucleotide sequence (GenBank No. AF464898). In contract to the recombinant product of the same nucleotide sequence, BmK AGAP, which displayed analgesic and anti-tumor effect, intravenous injection (i.v.) of BmK NT1 produced acute toxicity in mice with an LD50 value of 1.36 mg/kg. In primary cultured cerebellar granule cells, BmK NT1 produced a concentration-dependent cell death with an IC50 value of 0.65 μM (0.41-1.03 μM, 95% Confidence Intervals, 95% CI) which was abolished by TTX, a voltage-gated sodium channel (VGSC) blocker. We also demonstrated that BmK NT1 produced modest sodium influx in cerebellar granule cell cultures with an EC50 value of 2.19 μM (0.76-6.40 μM, 95% CI), an effect similar to VGSC agonist, veratridine. The sodium influx response was abolished by TTX suggesting that BmK NT1-induced sodium influx is solely through activation of VGSC. Considered these data together, we demonstrated that BmK NT1 activated VGSC and produced neurotoxicity in cerebellar granule cell cultures.
authors.affiliation: Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, 211198, PR China.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Zou
authors.affiliation: Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, 211198, PR China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: He
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Jinping
authors.initials: J
authors.lastname: Qiao
authors.affiliation: Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, 211198, PR China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing, 211198, PR China. Electronic address: zycao1999@hotmail.com.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Cao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D002850:Chromatography, Gel; D008516:Medicine, Chinese Traditional; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012604:Scorpion Venoms / Q000737:chemistry*
chemical_list: D010455:Peptides; D012604:Scorpion Venoms
keywords: BmK NT1; Buthus martensii Karsch; Cerebellar granule cells; Neurotoxicity; Voltage-gated sodium channels