PMID- 34419081 OWN - NLM STAT- MEDLINE DCOM- 20220124 LR - 20220124 IS - 1742-2094 (Electronic) IS - 1742-2094 (Linking) VI - 18 IP - 1 DP - 2021 Aug 21 TI - Soluble tumor necrosis factor-alpha-induced hyperexcitability contributes to retinal ganglion cell apoptosis by enhancing Nav1.6 in experimental glaucoma. PG - 182 LID - 10.1186/s12974-021-02236-6 [doi] LID - 182 AB - BACKGROUND: Neuroinflammation plays an important role in the pathogenesis of glaucoma. Tumor necrosis factor-alpha (TNF-alpha) is a major pro-inflammatory cytokine released from activated retinal glial cells in glaucoma. Here, we investigated how TNF-alpha induces retinal ganglion cell (RGC) hyperexcitability and injury. METHODS: Whole-cell patch-clamp techniques were performed to explore changes in spontaneous firing and evoked action potentials, and Na(+) currents in RGCs. Both intravitreal injection of TNF-alpha and chronic ocular hypertension (COH) models were used. Western blotting, immunofluorescence, quantitative real-time polymerase chain reaction (q-PCR), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) techniques were employed to investigate the molecular mechanisms of TNF-alpha effects on RGCs. RESULTS: Intravitreal injection of soluble TNF-alpha significantly increased the spontaneous firing frequencies of RGCs in retinal slices. When the synaptic transmissions were blocked, more than 90% of RGCs still showed spontaneous firing; both the percentage of cells and firing frequency were higher than the controls. Furthermore, the frequency of evoked action potentials was also higher than the controls. Co-injection of the TNF-alpha receptor 1 (TNFR1) inhibitor R7050 eliminated the TNF-alpha-induced effects, suggesting that TNF-alpha may directly act on RGCs to induce cell hyperexcitability through activating TNFR1. In RGCs acutely isolated from TNF-alpha-injected retinas, Na(+) current densities were upregulated. Perfusing TNF-alpha in RGCs of normal rats mimicked this effect, and the activation curve of Na(+) currents shifted toward hyperpolarization direction, which was mediated through p38 MAPK and STAT3 signaling pathways. Further analysis revealed that TNF-alpha selectively upregulated Nav1.6 subtype of Na(+) currents in RGCs. Similar to observations in retinas of rats with COH, intravitreal injection of TNF-alpha upregulated the expression of Nav1.6 proteins in both total cell and membrane components, which was reversed by the NF-kappaB inhibitor BAY 11-7082. Inhibition of TNFR1 blocked TNF-alpha-induced RGC apoptosis. CONCLUSIONS: TNF-alpha/TNFR1 signaling induces RGC hyperexcitability by selectively upregulating Nav1.6 Na(+) channels, thus contributing to RGC apoptosis in glaucoma. CI - (c) 2021. The Author(s). FAU - Cheng, Shuo AU - Cheng S AD - State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China. FAU - Wang, Hong-Ning AU - Wang HN AD - State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China. FAU - Xu, Lin-Jie AU - Xu LJ AD - State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China. FAU - Li, Fang AU - Li F AD - State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China. FAU - Miao, Yanying AU - Miao Y AD - State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China. FAU - Lei, Bo AU - Lei B AD - Institute of Neuroscience and Third Affiliated Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450003, China. FAU - Sun, Xinghuai AU - Sun X AD - Department of Ophthalmology at Eye & ENT Hospital, Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, 200031, China. xhsun@shmu.edu.cn. FAU - Wang, Zhongfeng AU - Wang Z AUID- ORCID: 0000-0002-2279-6885 AD - State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China. zfwang@fudan.edu.cn. LA - eng GR - 31872765/National Natural Science Foundation of China (CN)/ GR - 81790642/National Natural Science Foundation of China/ PT - Journal Article DEP - 20210821 PL - England TA - J Neuroinflammation JT - Journal of neuroinflammation JID - 101222974 RN - 0 (NAV1.6 Voltage-Gated Sodium Channel) RN - 0 (Scn8a protein, rat) RN - 0 (Tumor Necrosis Factor-alpha) SB - IM MH - Animals MH - Apoptosis/*drug effects MH - Disease Models, Animal MH - Glaucoma/*metabolism MH - Male MH - NAV1.6 Voltage-Gated Sodium Channel/*metabolism MH - Patch-Clamp Techniques MH - Rats MH - Rats, Sprague-Dawley MH - Retinal Ganglion Cells/*drug effects/metabolism MH - Tumor Necrosis Factor-alpha/*pharmacology PMC - PMC8380326 OTO - NOTNLM OT - Apoptosis OT - Glaucoma OT - Hyperexcitability OT - Nav1.6 OT - Neuroinflammation OT - Retinal ganglion cells OT - TNF-alpha COIS- The authors declare that they have no competing interests. EDAT- 2021/08/23 06:00 MHDA- 2022/01/27 06:00 PMCR- 2021/08/21 CRDT- 2021/08/22 20:28 PHST- 2021/05/10 00:00 [received] PHST- 2021/08/09 00:00 [accepted] PHST- 2021/08/22 20:28 [entrez] PHST- 2021/08/23 06:00 [pubmed] PHST- 2022/01/27 06:00 [medline] PHST- 2021/08/21 00:00 [pmc-release] AID - 10.1186/s12974-021-02236-6 [pii] AID - 2236 [pii] AID - 10.1186/s12974-021-02236-6 [doi] PST - epublish SO - J Neuroinflammation. 2021 Aug 21;18(1):182. doi: 10.1186/s12974-021-02236-6.