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Wang C, Cui C, Xie X, Chen B, Feng L, Jiang P. Calcitriol attenuates lipopolysaccharide-induced neuroinflammation and depressive-like behaviors by suppressing the P2X7R/NLRP3/caspase-1 pathway. Psychopharmacology (Berl) 2024; 241:1329-1343. [PMID: 38411637 DOI: 10.1007/s00213-024-06565-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 02/22/2024] [Indexed: 02/28/2024]
Abstract
RATIONALE Microglia-mediated neuroinflammation is a vital hallmark in progression of depression, while calcitriol exerts anti-inflammatory effects in the brain. The activation of the P2X7 receptor has an important link to neuroinflammation. However, it is unclear whether calcitriol treatment exerts anti-inflammatory effects in association with P2X7R activation. OBJECTIVE In this study, we assessed the antidepressive and neuroprotective effects of calcitriol on lipopolysaccharide (LPS)-mediated depressive-like behavior, neuroinflammation, and neuronal damage. METHODS In in vitro experiments, the BV2 cells were exposed to LPS, and the protective effects of calcitriol were assessed. For in vivo experiment, thirty-two male C57BL/6 mice were divided into four groups of control, calcitriol, LPS and LPS + calcitriol. Calcitriol was administered at 1 µg/kg for 14 days and LPS at 1 mg/kg once every other day for 14 days. The control group mice were given equal volumes of vehicles. All treatments were delivered intraperitoneally. RESULTS The in vitro experiments showed calcitriol inhibited the release of inflammatory mediators induced by LPS in BV2 cells. The in vivo experiments revealed that calcitriol alleviated LPS-induced behavioral abnormalities and spatial learning impairments. Moreover, calcitriol treatment reduced the mRNA levels of pro-inflammatory cytokines, while increasing anti-inflammatory cytokine levels in the hippocampus. Our results further revealed that calcitriol administration attenuated LPS-induced microglia activation by suppressing P2X7R/NLRP3/caspase-1 signaling. Moreover, calcitriol inhibited apoptosis of neurons in the hippocampus as evidenced by expression of apoptosis-related proteins and TUNEL assay. CONCLUSIONS Collectively, our findings demonstrated that calcitriol exerts antidepressive and neuroprotective effects through the suppression of the P2X7R/NLRP3/caspase-1 pathway both in LPS-induced inflammation models in vitro and in vivo.
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Affiliation(s)
- Changshui Wang
- Department of Neurosurgery, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, China
| | - Changmeng Cui
- Department of Neurosurgery, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, China
| | - Xin Xie
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, China
- Translational Pharmaceutical Laboratory, Jining First People's Hospital, Shandong First Medical University, Jining, China
| | - Beibei Chen
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, China
- Translational Pharmaceutical Laboratory, Jining First People's Hospital, Shandong First Medical University, Jining, China
| | - Lei Feng
- Department of Neurosurgery, Jining First People's Hospital, Shandong First Medical University, Jining, China.
| | - Pei Jiang
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, China.
- Translational Pharmaceutical Laboratory, Jining First People's Hospital, Shandong First Medical University, Jining, China.
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Mahemuti Y, Kadeer K, Su R, Abula A, Aili Y, Maimaiti A, Abulaiti S, Maimaitituerxun M, Miao T, Jiang S, Axier A, Aisha M, Wang Y, Cheng X. TSPO exacerbates acute cerebral ischemia/reperfusion injury by inducing autophagy dysfunction. Exp Neurol 2023; 369:114542. [PMID: 37717810 DOI: 10.1016/j.expneurol.2023.114542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Autophagy is considered a double-edged sword, with a role in the regulation of the pathophysiological processes of the central nervous system (CNS) after cerebral ischemia-reperfusion injury (CIRI). The 18-kDa translocator protein (TSPO) is a highly conserved protein, with its expression level in the nervous system closely associated with the regulation of pathophysiological processes. In addition, the ligand of TSPO reduces neuroinflammation in brain diseases, but the potential role of TSPO in CIRI is largely undiscovered. On this basis, we investigated whether TSPO regulates neuroinflammatory response by affecting autophagy in microglia. In our study, increased expression of TSPO was detected in rat brain tissues with transient middle cerebral artery occlusion (tMCAO) and in BV2 microglial cells exposed to oxygen-glucose deprivation or reoxygenation (OGD/R) treatment, respectively. In addition, we confirmed that autophagy was over-activated during CIRI by increased expression of autophagy activation related proteins with Beclin-1 and LC3B, while the expression of p62 was decreased. The degradation process of autophagy was inhibited, while the expression levels of LAMP-1 and Cathepsin-D were significantly reduced. Results of confocal laser microscopy and transmission electron microscopy (TEM) indicated that autophagy flux was disordered. In contrast, inhibition of TSPO prevented autophagy over-activation both in vivo and in vitro. Interestingly, suppression of TSPO alleviated nerve cell damage by reducing reactive oxygen species (ROS) and pro-inflammatory factors, including TNF-α and IL-6 in microglia cells. In summary, these results indicated that TSPO might affect CIRI by mediating autophagy dysfunction and thus might serve as a potential target for ischemic stroke treatment.
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Affiliation(s)
- Yusufu Mahemuti
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China; School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, PR China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, Zhejiang, PR China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, Zhejiang, PR China
| | - Kaheerman Kadeer
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Riqing Su
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Abudureheman Abula
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Yirizhati Aili
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Aierpati Maimaiti
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Subinuer Abulaiti
- Department of Epidemiology and Biostatistics, Institute of Public Health, Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | | | - Tong Miao
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Shihao Jiang
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Aximujiang Axier
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Maimaitili Aisha
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Yongxin Wang
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Xiaojiang Cheng
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China.
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Cheung G, Lin YC, Papadopoulos V. Translocator protein in the rise and fall of central nervous system neurons. Front Cell Neurosci 2023; 17:1210205. [PMID: 37416505 PMCID: PMC10322222 DOI: 10.3389/fncel.2023.1210205] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
Translocator protein (TSPO), a 18 kDa protein found in the outer mitochondrial membrane, has historically been associated with the transport of cholesterol in highly steroidogenic tissues though it is found in all cells throughout the mammalian body. TSPO has also been associated with molecular transport, oxidative stress, apoptosis, and energy metabolism. TSPO levels are typically low in the central nervous system (CNS), but a significant upregulation is observed in activated microglia during neuroinflammation. However, there are also a few specific regions that have been reported to have higher TSPO levels than the rest of the brain under normal conditions. These include the dentate gyrus of the hippocampus, the olfactory bulb, the subventricular zone, the choroid plexus, and the cerebellum. These areas are also all associated with adult neurogenesis, yet there is no explanation of TSPO's function in these cells. Current studies have investigated the role of TSPO in microglia during neuron degeneration, but TSPO's role in the rest of the neuron lifecycle remains to be elucidated. This review aims to discuss the known functions of TSPO and its potential role in the lifecycle of neurons within the CNS.
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Liu J, Hiser C, Li F, Hall R, Garavito RM, Ferguson-Miller S. New TSPO Crystal Structures of Mutant and Heme-Bound Forms with Altered Flexibility, Ligand Binding, and Porphyrin Degradation Activity. Biochemistry 2023; 62:1262-1273. [PMID: 36947867 PMCID: PMC10077581 DOI: 10.1021/acs.biochem.2c00612] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 03/09/2023] [Indexed: 03/24/2023]
Abstract
The ancient protein TSPO (translocator protein 18kD) is found in all kingdoms and was originally identified as a binding site of benzodiazepine drugs. Its physiological function remains unclear, although porphyrins are conserved ligands. Several crystal structures of bacterial TSPO and nuclear magnetic resonance structures of a mouse form have revealed monomer and dimer configurations, but there have been no reports of structures with a physiological ligand. Here, we present the first X-ray structures of Rhodobacter sphaeroides TSPO with a physiological ligand bound. Two different variants (substituting threonine for alanine at position 139 (A139T) and phenylalanine for alanine at position 138 (A138F)) yielded well-diffracting crystals giving structures of both apo- and heme-containing forms. Both variants have wild-type micromolar affinity for heme and protoporphyrin IX, but A139T has very low ability to accelerate the breakdown of porphyrin in the presence of light and oxygen. The binding of heme to one protomer of the dimer of either mutant induces a more rigid structure, both in the heme-binding protomer and the protomer without heme bound, demonstrating an allosteric response. Ensemble refinement of the X-ray data reveals distinct regions of altered flexibility in response to single heme binding to the dimer. The A139T variant shows a more rigid structure overall, which may relate to extra hydrogen bonding of waters captured in the heme crevice. As TSPO has been suggested to have a role in heme delivery from mitochondria to the cytoplasm, the new structures provide potential clues regarding the structural basis of such activity.
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Affiliation(s)
- Jian Liu
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Carrie Hiser
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
| | - Fei Li
- Amgen
Inc., San Francisco, California 94080, United States
| | - Robert Hall
- Pharmacology
and Chemical Biology, University of Pittsburgh
School of Medicine, Pittsburgh, Pennsylvania 15213, United States
| | - R. Michael Garavito
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
| | - Shelagh Ferguson-Miller
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
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Bao N, Liu J, Peng Z, Zhang R, Ni R, Li R, Wu J, Liu Z, Pan B. Identification of circRNA-miRNA-mRNA networks to explore the molecular mechanism and immune regulation of postoperative neurocognitive disorder. Aging (Albany NY) 2022; 14:8374-8393. [PMID: 36279395 PMCID: PMC9648807 DOI: 10.18632/aging.204348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/14/2022] [Indexed: 11/25/2022]
Abstract
Postoperative neurocognitive disorder (PND) is a common complication in older patients. However, its pathogenesis has still remained elusive. Recent studies have shown that circular RNA (circRNA) plays an important role in the development of neurodegenerative diseases, such as PND after surgery. CircRNA, as a competitive endogenous RNA (ceRNA), mainly acts as a molecular sponge for miRNA to "adsorb" microRNA (miRNA) and to reduce the inhibitory effects of miRNAs on target mRNA. The sequencing data of circRNA were obtained from the Gene Expression Omnibus (GEO) database. By bioinformatic methods, circAtlas, miRDB, miRTarBase and miRwalk databases were applied to construct circRNA-miRNA-mRNA networks and screen differentially expressed mRNAs. To improve the accuracy of the data, we randomly divided aging mice into control (non-PND group) and PND groups, and used high-throughput sequencing to analyze their brain hippocampal tissue for analysis. Three key genes were cross-detected in the data of both groups, which were Unc13c, Tbx20 and St8sia2 (as hub genes), providing new targets for PND treatment. According to the results of the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, immune cell infiltration analysis, gene set enrichment analysis (GSEA), Connectivity Map (CMap) analysis, quantitative real-time polymerase chain reaction (qRT-PCR), the genes that were not related to the central nervous system were removed, and finally, mmu_circ_0000331/miR-1224-3p/Unc13c and mmu_circ_0000406/miR-24-3p/St8sia2 ceRNA networks were identified. In addition, the CMap method was used to select the top 4 active compounds with the largest negative correlation absolute values, including cimaterol, Rucaparib, FG-7142, and Hydrocortisone.
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Affiliation(s)
- Ning Bao
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
- Department of Anesthesiology, Shenyang Women’s and Children’s Hospital, Shenyang, Liaoning, China
| | - Jiping Liu
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Zhe Peng
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Rong Zhang
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Rufei Ni
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Runzuan Li
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Jian Wu
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Zhenhua Liu
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Botao Pan
- Department of Anesthesiology, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
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TSPO Ligands Protect against Neuronal Damage Mediated by LPS-Induced BV-2 Microglia Activation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5896699. [PMID: 35401924 PMCID: PMC8986436 DOI: 10.1155/2022/5896699] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/19/2022] [Accepted: 03/07/2022] [Indexed: 12/20/2022]
Abstract
Neuroinflammation is a critical pathological process of neurodegenerative diseases, and alleviating the inflammatory response caused by abnormally activated microglia might be valuable for treatment. The 18 kDa translocator protein (TSPO), a biomarker of neuroinflammation, is significantly elevated in activated microglia. However, the role of TSPO in microglia activation has not been well demonstrated. In this study, we evaluated the role of TSPO and its ligands PK11195 and Midazolam in LPS-activated BV-2 microglia cells involving mitophagy process and the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome activation. In the microglia-neuron coculture system, the neurotoxicity induced by LPS-activated microglia and the neuroprotective effects of PK11195 and Midazolam were evaluated. Our results showed that after being stimulated by LPS, the expression of TSPO was increased, and the process of mitophagy was inhibited in BV-2 microglia cells. Inhibition of mitophagy was reversed by pretreatment with PK11195 and Midazolam. And the NLRP3 inflammasome was increased in LPS-activated BV-2 microglia cells in the microglia-neuron coculture system; pretreatment with PK11195 and Midazolam limited this undesirable situation. Lastly, PK11195 and Midazolam improved the cell viability and reduced apoptosis of neuronal cells in the microglia-neuron coculture system. Taken together, TSPO ligands PK11195 and Midazolam showed neuroprotective effects by reducing the inflammatory response of LPS-activated microglia, which may be related to the enhancement of mitophagy and the inhibition of NLRP3 inflammasome.
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