Calpain- and caspase-mediated alphaII-spectrin and tau proteolysis in rat cerebrocortical neuronal cultures after ecstasy or methamphetamine exposure.
Abuse of 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) and methamphetamine (Meth or Speed) is a growing international problem with an estimated 250 million users of psychoactive drugs worldwide. It is important to demonstrate and understand the mechanism of neurotoxicity so potential prevention and treatment therapies can be designed. In this study rat primary cerebrocortical neuron cultures were challenged with MDMA and Meth (1 or 2 mM) for 24 and 48 h and compared to the excitotoxin N-methyl-D-aspartate (NMDA). The neurotoxicity of these drugs, as assessed by microscopy, lactate dehydrogenase release and immunoblot, was shown to be both dose- and time-dependent. Immunoblot analysis using biomarkers of cell death showed significant proteolysis of both alphaII-spectrin and tau proteins. Breakdown products of alphaII-spectrin (SBDPs) of 150, 145, and 120 kDa and tau breakdown products (TBDPs) of 45, 32, 26, and 14 kDa were observed. The use of the protease inhibitors calpain inhibitor SJA6017 and caspase inhibitors z-VAD-fmk and Z-D-DCB, attenuated drug-induced alphaII-spectrin and tau proteolysis. The calpain inhibitor reduced the calpain-induced breakdown products SBDP145 and TBDP14, but there was an offset increase in the caspase-mediated breakdown products SBDP120 and TBDP45. The caspase inhibitors, on the other hand, decreased SBDP120 and TBDP45. These data suggest that both MDMA and Meth trigger concerted proteolytic attacks of the structural proteins by both calpain and caspase family of proteases. The ability of the protease inhibitors to reduce the damage caused by these drugs suggests that the treatment arsenal could include similar drugs as possible tools to combat the drug-induced neurotoxicity in vivo.
Warren
Matthew W
MW
Center for Traumatic Brain Injury Studies, Department of Neuroscience, McKnight Brain Institute of the University of Florida, Gainesville, FL, USA.
Zheng
Wenrong
W
Kobeissy
Firas H
FH
Cheng Liu
Ming
M
Hayes
Ronald L
RL
Gold
Mark S
MS
Larner
Stephen F
SF
Wang
Kevin K W
KK
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000378:metabolism; D008694:Methamphetamine / Q000633:toxicity*; D008840:Microfilament Proteins / Q000378:metabolism*; D008970:Molecular Weight; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000633:toxicity*; D016202:N-Methylaspartate / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011619:Psychotropic Drugs / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D033921:Vesicular Transport Proteins / Q000378:metabolism*; D016875:tau Proteins / Q000378:metabolism*
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D018690:Excitatory Amino Acid Agonists; C489131:Mapt protein, rat; D008840:Microfilament Proteins; C109145:N-(4-fluorophenylsulfonyl)-L-valyl-L-leucinal; D010446:Peptide Fragments; D011619:Psychotropic Drugs; C422208:Sptan1 protein, rat; D033921:Vesicular Transport Proteins; C093260:benzyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D016875:tau Proteins; D001224:Aspartic Acid; D008694:Methamphetamine; D016202:N-Methylaspartate; D002154:Calpain; D020169:Caspases; D018817:N-Methyl-3,4-methylenedioxyamphetamine