Abstract
Artemether, a lipid-soluble derivative of artemisinin has been reported to possess anti-inflammatory properties. In this study, we have investigated the molecular mechanisms involved in the inhibition of neuroinflammation by the drug. The effects of artemether on neuroinflammation-mediated HT22 neuronal toxicity were also investigated in a BV2 microglia/HT22 neuron co-culture. To investigate effects on neuroinflammation, we used LPS-stimulated BV2 microglia treated with artemether (5–40 μM) for 24 h. ELISAs and western blotting were used to detect pro-inflammatory cytokines, nitric oxide, prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 and microsomal prostaglandin E synthase-1 (mPGES-1). Beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) activity and Aβ levels were measured with ELISA kits. Protein levels of targets in nuclear factor kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) signalling, as well as heme oxygenase-1 (HO-1), NQO1 and nuclear factor-erythroid 2-related factor 2 (Nrf2) were also measured with western blot. NF-κB binding to the DNA was investigated using electrophoretic mobility shift assays (EMSA). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), DNA fragmentation and reactive oxygen species (ROS) assays in BV2-HT22 neuronal co-culture were used to evaluate the effects of artemether on neuroinflammation-induced neuronal death. The role of Nrf2 in the anti-inflammatory activity of artemether was investigated in BV2 cells transfected with Nrf2 siRNA. Artemether significantly suppressed pro-inflammatory mediators (NO/iNOS, PGE2/COX-2/mPGES-1, tumour necrosis factor-alpha (TNFα) and interleukin (IL)-6); Aβ and BACE-1 in BV2 cells following LPS stimulation. These effects of artemether were shown to be mediated through inhibition of NF-κB and p38 MAPK signalling. Artemether produced increased levels of HO-1, NQO1 and GSH in BV2 microglia. The drug activated Nrf2 activity by increasing nuclear translocation of Nrf2 and its binding to antioxidant response elements in BV2 cells. Transfection of BV2 microglia with Nrf2 siRNA resulted in the loss of both anti-inflammatory and neuroprotective activities of artemether. We conclude that artemether induces Nrf2 expression and suggest that Nrf2 mediates the anti-inflammatory effect of artemether in BV2 microglia. Our results suggest that this drug has a therapeutic potential in neurodegenerative disorders.
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Abbreviations
- AD:
-
Alzheimer’s disease
- ANOVA:
-
Analysis of variance
- BACE-1:
-
Beta-site amyloid precursor protein cleaving enzyme 1
- CNS:
-
Central nervous system
- COX:
-
Cyclooxygenase
- DMSO:
-
Dimethyl sulfoxide
- FBS:
-
Foetal bovine serum
- IκB:
-
Inhibitor of kappa B
- IL:
-
Interleukin
- iNOS:
-
Inducible nitric oxide synthase
- LPS:
-
Lipopolysaccharide
- MAPK:
-
Mitogen-activated protein kinase
- HO-1:
-
Heme oxygenase-1
- NO:
-
Nitric oxide
- Nrf2:
-
Nuclear factor-erythroid 2-related factor 2
- NF-κB:
-
Nuclear factor kappa B
- TNFα:
-
Tumour necrosis factor-alpha
References
Salter M, Beggs S (2014) Sublime microglia: expanding roles for the guardians of the CNS. Cell 158(1):15–24
Perry V, Teeling J (2013) Microglia and macrophages of the central nervous system: the contribution of microglia priming and systemic inflammation to chronic neurodegeneration. Semin Immunopathol 35(5):601–612
Mosher K, Wyss-Coray T (2014) Microglial dysfunction in brain aging and Alzheimer’s disease. Biochem Pharmacol 88(4):594–604
Prokop S, Miller KR, Heppner FL (2013) Microglia actions in Alzheimer’s disease. Acta Neuropathol 126(4):461–477
Kaltschmidt B, Kaltschmidt C (2009) NF-kappaB in the nervous system. Cold Spring Harb Perspect Biol 1(3):a001271. doi:10.1101/cshperspect.a001271
Yong H, Koh M, Moon A (2009) The p38MAPK inhibitors for the treatment of inflammatory diseases and cancer. Expert Opin Investig Drugs 18(12):1893–1905
Corrêa S, Eales K (2012) The role of p38 MAPK and Its substrates in neuronal plasticity and neurodegenerative disease. J Signal Transduct 2012:649079. doi:10.1155/2012/649079
Krementsov DN, Thornton TM, Teuscher C, Rincon M (2013) The emerging role of p38 mitogen-activated protein kinase in multiple sclerosis and its models. Mol Cell Biol 33(19):3728–3734
Diego G, Hugh P (2015) Microglial dynamics and role in the healthy and diseased brain: a paradigm of functional plasticity. Neuroscientist 21(2):169–184
Wu LH, Lin C, Lin HY, Liu YS, Wu CY, Tsai CF, Chang PC, Yeh WL, et al (2015) Naringenin suppresses neuroinflammatory responses through inducing suppressor of cytokine signaling 3 expression. Mol Neurobiol. doi:10.1007/s12035-014-9042-9
Heneka M, O’Banion M (2007) Inflammatory processes in Alzheimer’s disease. J Neuroimmunol 184(1–2):69–91
Lee JW, Lee YK, Yuk DY, Choi DY, Ban SB, Oh KW, Hong JT (2008) Neuroinflammation induced by lipopolysaccharide causes impairment through enhancement of beta-amyloid generation. J Neuroinflammation 5:37. doi:10.1186/1742-2094-5-37
Lee YJ, Choi DY, Choi IS, Han JY, Jeong HS, Han SB, Oh KW, Hong JT (2011) Inhibitory effect of a tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl)-2-butenal on amyloid-β generation and inflammatory reactions via inhibition of NF-κB and STAT3 activation in cultured astrocytes and microglial BV-2 cells. J Neuroinflammation 8:132. doi:10.1186/1742-2094-8-132
Song SY, Jung YY, Hwang CJ, Lee HP, Sok CH, Kim JH, Lee SM, Seo HO et al (2014) Inhibitory effect of ent-Sauchinone on amyloidogenesis via inhibition of STAT3-mediated NF-κB activation in cultured astrocytes and microglial BV-2 cells. J Neuroinflammation 11:118. doi:10.1186/1742-2094-11-118
Rojo AI, McBean G, Cindric M, Egea J, López MG, Rada P, Zarkovic N, Cuadrado A (2014) Redox control of microglial function: molecular mechanisms and functional significance. Antioxid Redox Signal 21(13):1766–1801
Kapturczak MH, Wasserfall C, Brusko T, Campbell-Thompson M, Ellis TM, Atkinson MA, Agarwal A (2004) Heme oxygenase-1 modulates early inflammatory responses: evidence from the heme oxygenase-1-deficient mouse. Am J Pathol 165(3):1045–1053
Kanninen K, Malm TM, Jyrkkänen HK, Goldsteins G, Keksa-Goldsteine V, Tanila H, Yamamoto M, Ylä-Herttuala S et al (2008) Nuclear factor erythroid 2-related factor 2 protects against beta amyloid. Mol Cell Neurosci 39(3):302–313
Ramsey CP, Glass CA, Montgomery MB, Lindl KA, Ritson GP, Chia LA, Hamilton RL, Chu CT et al (2007) Expression of Nrf2 in neurodegenerative diseases. J Neuropathol Exp Neurol 66(1):75–85
Miller LH, Su X (2011) Artemisinin: discovery from Chinese herbal garden. Cell 146(6):855–858
Cuzzocrea S, Saadat F, Di Paola R, Mirshafiey A (2005) Artemether: a new therapeutic strategy in experimental rheumatoid arthritis. Immunopharmacol Immunotoxicol 27(4):615–630
Wu J (2011) Investigation of anti-inflammatory effect of artemether in mouse model of colitis. Inflamm Bowel Dis 17:S18–S19
Zhang F, Wang H, Wu Q, Lu Y, Nie J, Xie X, Shi J (2013) Resveratrol protects cortical neurons against microglia-mediated neuroinflammation. Phytother Res 27(3):344–349
Gao HM, Hong JS (2008) Why neurodegenerative diseases are progressive: uncontrolled inflammation drives disease progression. Trends Immunol 29(8):57–65
Kuroki Y, Sasaki Y, Kamei D, Akitake Y, Takahashi M, Uematsu S, Akira S, Nakatani Y et al (2012) Deletion of microsomal prostaglandin E synthase-1 protects neuronal cells from cytotoxic effects of β-amyloid peptide fragment 31–35. Biochem Biophys Res Commun 424(3):409–413
Olajide OA, Kumar A, Velagapudi R, Okorji UP, Fiebich BL (2014) Punicalagin inhibits neuroinflammation in LPS-activated rat primary microglia. Mol Nutr Food Res 58(9):1843–1851
Okorji U, Olajide O (2014) A semi-synthetic derivative of artemisinin, artesunate inhibits prostaglandin E2 production in LPS/IFNgamma-activated BV2 microglia. Bioorg Med Chem 22(17):4726–4734
Velagapudi R, Aderogba M, Olajide O (2014) TIliroside, a dietary glycosidic flavonoid, inhibits TRAF-6/NF-kappaB/p38-mediated neuroinflammation in activated BV2 microglia. Biochim Biophys Acta 1840(12):3311–3319
Zhu C, Xiong Z, Chen X, Peng F, Hu X, Chen Y, Wang Q (2012) Artemisinin attenuates lipopolysaccharide-stimulated proinflammatory responses by inhibiting NF-κB pathway in microglia cells. PLoS One 7(4), e35125. doi:10.1371/journal.pone.0035125
Munoz L, Ammit A (2010) Targeting p38 MAPK pathway for the treatment of Alzheimer’s disease. Neuropharmacology 58(3):561–568
Xing B, Bachstetter AD, Van Eldik LJ (2011) Microglial p38α MAPK is critical for LPS-induced neuron degeneration, through a mechanism involving TNFα. Mol Neurodegener 6:84. doi:10.1186/1750-1326-6-84
Hsu MJ, Chang CK, Chen MC, Chen BC, Ma HP, Hong CY, Lin CH (2010) Apoptosis signal-regulating kinase 1 in peptidoglycan induced COX-2 expression in macrophages. J Leukoc Biol. 87(6):1069–1082
Borchelt DR, Ratovitski T, van Lare J, Lee MK, Gonzales V, Jenkins NA, Copeland NG, Price DL et al (1997) Accelerated amyloid deposition in the brains of transgenic mice coexpression mutant presenilin 1 and amyloid precursor proteins. Neuron 19(4):939–945
Sambamurti K, Kinsey R, Maloney B, Ge YW, Lahiri DK (2004) Gene structure and organisation of human beta-secretase (BACE) promoter. FASEB J 18(9):1034–1036
Kim JA, Yun HM, Jin P, Lee HP, Han JY, Udumula V, Moon DC, Han SB et al (2014) Inhibitory effect of a 2,4-bis(4-hydroxyphenyl)-2-butenal diacetate on neuroinflammatory reactions via inhibition of STAT1 and STAT3 activation in cultured astrocytes and microglial BV-2 cells. Neuropharmacology 79:476–487
Chen CH, Zhou W, Liu S, Deng Y, Cai F, Tone M, Tone Y, Tong Y et al (2012) Increased NF-κB signalling up-regulated BACE-1 expression and its therapeutic potential in Alzheimer’s disease. Int J Neuropsychopharmacol 15(1):77–90
Innamorato NG, Rojo AI, García-Yagüe AJ, Yamamoto M, de Ceballos ML, Cuadrado A (2008) The transcription factor Nrf2 is a therapeutic target against brain inflammation. J Immunol 181(1):680–689
Foresti R, Bains SK, Pitchumony TS, de Castro Brás LE, Drago F, Dubois-Randé JL, Bucolo C, Motterlini R (2013) Small molecule activators of the Nrf2-HO-1 antioxidant axis modulate heme metabolism and inflammation in BV2 microglia cells. Pharmacol Res 76:132–148
Syapin PJ (2008) Regulation of haeme oxygenase-1 for treatment of neuroinflammation and brain disorders. Br J Pharmacol 155(5):623–640
Lee IS, Lim J, Gal J, Kang JC, Kim HJ, Kang BY, Choi HJ (2011) Anti-inflammatory activity of xanthohumol involves heme oxygenase-1 induction via NRF2-ARE signaling in microglial BV2 cells. Neurochem Int 58(2):153–160
Lee IS, Ryu DK, Lim J, Cho S, Kang BY, Choi HJ (2012) Artesunate activates Nrf2 pathway-driven anti-inflammatory potential through ERK signaling in microglial BV2 cells. Neurosci Lett 509(1):17–21
Ho WE, Cheng C, Peh HY, Xu F, Tannenbaum SR, Ong CN, Wong WS (2012) Anti-malarial drug artesunate ameliorates oxidative lung damage in experimental allergic asthma. Free Radic Biol Med 53(3):498–507
Ng DS, Liao W, Tan WS, Chan TK, Loh XY, Wong WS (2014) Anti-malarial drug artesunate protects against cigarette smoke-induced lung injury in mice. Phytomedicine 21(12):1638–1644
Olmos G, Lladó J (2014) Tumor necrosis factor alpha: a link between neuroinflammation and excitotoxicity. Mediators Inflamm 2014:861231. doi:10.1155/2014/861231
Efferth T, Oesch F (2004) Oxidative stress response of tumor cells: microarray-based comparison between artemisinins and anthracyclines. Biochem Pharmacol 68(1):3–10
Acknowledgments
Uchechukwu P Okorji and Ravikanth Velagapudi are funded by a partial PhD scholarship from the University of Huddersfield. Abdelmeneim El-Bakoush was funded by a PhD scholarship from the Libyan Government. This study was partially funded by the University of Huddersfield (University Research Fund/International Networking Fund) awarded to Dr Olumayokun Olajide.
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The authors declare that they have no competing interests.
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Uchechukwu P. Okorji and Ravikanth Velagapudi contributed equally to this work.
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Okorji, U.P., Velagapudi, R., El-Bakoush, A. et al. Antimalarial Drug Artemether Inhibits Neuroinflammation in BV2 Microglia Through Nrf2-Dependent Mechanisms. Mol Neurobiol 53, 6426–6443 (2016). https://doi.org/10.1007/s12035-015-9543-1
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DOI: https://doi.org/10.1007/s12035-015-9543-1
Keywords
- Artemether
- Neuroinflammation
- BV2 microglia
- HT22 hippocampal neurons
- NF-κB
- Nrf2