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Liu HW, Gong LN, Lai K, Yu XF, Liu ZQ, Li MX, Yin XL, Liang M, Shi HS, Jiang LH, Yang W, Shi HB, Wang LY, Yin SK. Bilirubin gates the TRPM2 channel as a direct agonist to exacerbate ischemic brain damage. Neuron 2023; 111:1609-1625.e6. [PMID: 36921602 DOI: 10.1016/j.neuron.2023.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 10/18/2022] [Accepted: 02/13/2023] [Indexed: 03/16/2023]
Abstract
Stroke prognosis is negatively associated with an elevation of serum bilirubin, but how bilirubin worsens outcomes remains mysterious. We report that post-, but not pre-, stroke bilirubin levels among inpatients scale with infarct volume. In mouse models, bilirubin increases neuronal excitability and ischemic infarct, whereas ischemic insults induce the release of endogenous bilirubin, all of which are attenuated by knockout of the TRPM2 channel or its antagonist A23. Independent of canonical TRPM2 intracellular agonists, bilirubin and its metabolic derivatives gate the channel opening, whereas A23 antagonizes it by binding to the same cavity. Knocking in a loss of binding point mutation for bilirubin, TRPM2-D1066A, effectively antagonizes ischemic neurotoxicity in mice. These findings suggest a vicious cycle of stroke injury in which initial ischemic insults trigger the release of endogenous bilirubin from injured cells, which potentially acts as a volume neurotransmitter to activate TRPM2 channels, aggravating Ca2+-dependent brain injury.
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Affiliation(s)
- Han-Wei Liu
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Li-Na Gong
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Ke Lai
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Xia-Fei Yu
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhen-Qi Liu
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ming-Xian Li
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Xin-Lu Yin
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Department of Head & Neck Surgery, Renji Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Min Liang
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Department of Otorhinolaryngology Head & Neck Surgery, Xinhua Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Hao-Song Shi
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Lin-Hua Jiang
- Department of Physiology and Pathophysiology, School of Basic Sciences, Xinxiang Medical University, Xinxiang, Henan Province 453003, China; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Wei Yang
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Hai-Bo Shi
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China.
| | - Lu-Yang Wang
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Shan-Kai Yin
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China.
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Li M, Liu Z, Lai K, Liu H, Gong L, Shi H, Zhang W, Wang H, Shi H. Enhanced recruitment of glutamate receptors underlies excitotoxicity of mitral cells in acute hyperammonemia. Front Cell Neurosci 2022; 16:1002671. [DOI: 10.3389/fncel.2022.1002671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/05/2022] [Indexed: 11/13/2022] Open
Abstract
Hepatic encephalopathy (HE)–a major complication of liver disease–has been found to increase the risk of olfactory dysfunction, which may be attributed to elevated levels of ammonia/ammonium in the blood and cerebrospinal fluid. However, the cellular mechanisms underlying hyperammonemia-induced olfactory dysfunction remain unclear. By performing patch-clamp recordings of mitral cells (MCs) in the mouse olfactory bulb (OB), we found that 3 mM ammonium (NH4+) increased the spontaneous firing frequency and attenuated the amplitude, but synaptic blockers could prevent the changes, suggesting the important role of glutamate receptors in NH4+-induced hyperexcitability of MCs. We also found NH4+ reduced the currents of voltage-gated K+ channel (Kv), which may lead to the attenuation of spontaneous firing amplitude by NH4+. Further studies demonstrated NH4+ enhanced the amplitude and integral area of long-lasting spontaneous excitatory post-synaptic currents (sEPSCs) in acute OB slices. This enhancement of excitatory neurotransmission in MCs occurred independently of pre-synaptic glutamate release and re-uptake, and was prevented by the exocytosis inhibitor TAT-NSF700. In addition, an NH4+-induced increasement in expression of NR1 and GluR1 was detected on cytoplasmic membrane, indicating that increased trafficking of glutamate receptors on membrane surface in MCs is the core mechanism. Moreover, NH4+-induced enhanced activity of glutamate receptors in acute OB slices caused cell death, which was prevented by antagonizing glutamate receptors or chelating intracellular calcium levels. Our study demonstrates that the enhancement of the activity and recruitment of glutamate receptor directly induces neuronal excitotoxicity, and contributes to the vulnerability of OB to acute hyperammonemia, thus providing a potential pathological mechanism of olfactory defects in patients with hyperammonemia and HE.
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Zhou C, Sun R, Sun C, Gu M, Guo C, Zhang J, Du Y, Gu H, Liu Q. Minocycline protects neurons against glial cells-mediated bilirubin neurotoxicity. Brain Res Bull 2019; 154:102-105. [PMID: 31733348 DOI: 10.1016/j.brainresbull.2019.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/05/2019] [Accepted: 11/11/2019] [Indexed: 10/25/2022]
Abstract
Unconjugated bilirubin, the end product of heme catabolism and antioxidant, induced brain damage in human neonates is a well-recognized clinical syndrome. However, the cellular and molecular mechanisms underlying bilirubin neurotoxicity remain unclear. To characterize the sequence of events leading to bilirubin-induced neurotoxicity, we investigated whether bilirubin-induced glial activation was involved in bilirubin neurotoxicity by exposing co-cultured rat glial cells and cerebellar granule neurons (CGN) to bilirubin. We found that bilirubin could markedly induce the expression of TNF-α and iNOS in glial cells, and even at low concentrations, the co-culture of glial cells with neurons significantly enhances neurotoxicity of bilirubin. Pretreatment of the co-cultured cells with minocycline protected CGN from glia-mediated bilirubin neurotoxicity and inhibited overexpression of TNF-α and iNOS in glia. Furthermore, we found that high doses of bilirubin were able to induce glial injury, and minocycline attenuated bilirubin-induced glial cell death. Our data suggest that glial cells play an important role in brain damage caused by bilirubin, and minocycline blocks bilirubin-induced encephalopathy possibly by directly and indirectly inhibiting neuronal death pathways.
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Affiliation(s)
- Changwei Zhou
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Rong Sun
- Department of Outpatient OR, The 1st Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Chongyi Sun
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Minghao Gu
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Chuan Guo
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Jiyan Zhang
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Yansheng Du
- Department of Neurology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA
| | - Huiying Gu
- Department of Neurology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
| | - Qingpeng Liu
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China.
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