Methamphetamine Induces Apoptosis of Microglia via the Intrinsic Mitochondrial-Dependent Pathway
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Methamphetamine (METH) is a drug of abuse, the acute and chronic use of which induces neurotoxic responses in the human brain, ultimately leading to neurocognitive disorders. Our goals were to understand the impact of METH on microglial mitochondrial respiration and to determine whether METH induces the activation of the mitochondrial-dependent intrinsic apoptosis pathway in microglia. We assessed the expression of pro- apoptosis genes using qPCR of RNA extracted from a human microglial cell line (HTHU). We examined the apoptosis-inducing effects of METH on microglial cells using digital holographic microscopy (DHM) to quantify real-time apoptotic volume decrease (AVD) in microglia in a noninvasive manner. METH treatment significantly increased AVD, activated Caspase 3/7, increased the gene expression levels of the pro- apoptosis proteins, APAF-1 and BAX, and decreased mitochondrial DNA content. Using immunofluorescence analysis, we found that METH increased the expression of the mitochondrial proteins cytochrome c and MCL-1, supporting the activation of mitochondrion-dependent (intrinsic) apoptosis pathway. Cellular bio-energetic flux analysis by Agilent Seahorse XF Analyzer revealed that METH treatment increased both oxidative and glycolytic respiration after 3 h, which was sustained for at least 24 h. Several events, such as oxidative stress, neuro-inflammatory responses, and mitochondrial dysfunction, may converge to mediate METH-induced apoptosis of microglia that may contribute to neurotoxicity of the CNS. Our study has important implications for therapeutic strategies aimed at preserving mitochondrial function in METH abusing patients.
KeywordsApoptosis Mitochondria Microglia Methamphetamine Neurotoxicity Neuroinflammatory
The authors acknowledge grant support from the Dr. Louis Sklarow Memorial Trust (SDM) and the Troup Fund of the Kaleida Health Foundations (SAS). The authors are grateful to Dr. Jonathan Karn, Chairman and Reinberger Professor of Molecular Biology, and Director of the CASE Center for AIDS Research, Case Western Reserve University, Cleveland, OH for the generous donation of the HTHU cell line.
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Conflict of Interest
Authors declare no conflict of interests.
- Cadet JL, Krasnova IN (2007) Interactions of HIV and methamphetamine: cellular and molecular mechanisms of toxicity potentiation. Neurotox Res 12(3):181–204Google Scholar
- Cadet JL, Jayanthi S, Deng X (2005) Methamphetamine-induced neuronal apoptosis involves the activation of multiple death pathways. Review. Neurotox Res 8(3-4):199–206Google Scholar
- Coelho-Santos V, Gonçalves J, Fontes-Ribeiro C, Silva AP (2012) Prevention of methamphetamine-induced microglial cell death by TNF-α and IL-6 through activation of the JAK-STAT pathway. J Neuroinflammation 6(9):103 https://doi.org/10.1186/1742-2094-9-103
- Garcia-Mesa Y, Jay TR, Checkley MA, Luttge B, Dobrowolski C, Valadkhan S, Landreth GE, Karn J, Alvarez-Carbonell D (2017) Immortalization of primary microglia: a new platform to study HIV regulation in the central nervous system. J Neuro-Oncol 23(1):47–66Google Scholar
- Sekine Y, Ouchi Y, Sugihara G, Takei N, Yoshikawa E, Nakamura K, Iwata Y, Tsuchiya KJ, Suda S, Suzuki K, Kawai M, Takebayashi K, Yamamoto S, Matsuzaki H, Ueki T, Mori N, Gold MS, Cadet JL (2008) Methamphetamine causes microglial activation in the brains of human abusers. J Neurosci 28:5756–5761CrossRefPubMedPubMedCentralGoogle Scholar
- Yu S, Zhu L, Shen Q, Bai X, Di X (2015) Recent advances in methamphetamine neurotoxicity mechanisms and its molecular pathophysiology. Behav Neurol volume 2015, Article ID 103969, 11 pages, 2015. https://doi.org/10.1155/2015/103969