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Zhu W, Zhang H, Niu T, Liu K, Fareeduddin Mohammed Farooqui H, Sun R, Chen X, Yuan Y, Wang S. Microglial SCAP deficiency protects against diabetes-associated cognitive impairment through inhibiting NLRP3 inflammasome-mediated neuroinflammation. Brain Behav Immun 2024; 119:154-170. [PMID: 38570101 DOI: 10.1016/j.bbi.2024.03.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/25/2024] [Accepted: 03/30/2024] [Indexed: 04/05/2024] Open
Abstract
Hyperglycemia-induced pathological microglial responses and subsequent neuronal damage are notable characteristics of diabetes-associated cognitive impairment (DACI). Cholesterol accumulation in the brain is a prevalent consequence of diabetes mellitus (DM), exacerbating pathological microglial responses. Regarding disordered glucose and lipid metabolism, the Sterol Regulatory Element-Binding Protein (SREBP) cleavage-activating protein (SCAP), a cholesterol sensor, exhibits increased expression and abnormal translocation from the endoplasmic reticulum to the Golgi, amplifying the inflammatory response. Therefore, we hypothesized that overexpression of microglia-SCAP and cholesterol accumulation in DM mice could induce pathological microglial responses associated with DACI. Our type 2 DM mice model presented an abnormal increase in microglial SCAP expression. The functional loss of microglia-specific SCAP in DM mice improved cognitive impairment, neuronal synaptic plasticity deficits, and abnormal microglial responses. Mechanistically, the accumulated SCAP directly bound to and enhanced the activation of the microglial-specific inflammatory amplifier, NLRP3 inflammasome, in Golgi, thereby increasing pathological microglial responses and promoting neuronal damage. These findings indicate an important regulatory axis of microglial responses from SCAP to the NLRP3 inflammasome pathway in microglia. These underscore the crosstalk between cholesterol disorders and pathological microglial responses, offering a promising avenue for pharmaceutical interventions in DACI.
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Affiliation(s)
- Wenwen Zhu
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China; School of Medicine, Southeast University, Nanjing 210009, China
| | - Haoqiang Zhang
- Department of Endocrinology, Center for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China
| | - Tong Niu
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China; School of Medicine, Southeast University, Nanjing 210009, China
| | - Kunyu Liu
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China; School of Medicine, Southeast University, Nanjing 210009, China
| | - Huzaifa Fareeduddin Mohammed Farooqui
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China; School of Medicine, Southeast University, Nanjing 210009, China
| | - Ruoyu Sun
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China; School of Medicine, Southeast University, Nanjing 210009, China
| | - Xiu Chen
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China; School of Medicine, Southeast University, Nanjing 210009, China
| | - Yang Yuan
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China.
| | - Shaohua Wang
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing 210009, China.
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Qian Y, Yang L, Chen J, Zhou C, Zong N, Geng Y, Xia S, Yang H, Bao X, Chen Y, Xu Y. SRGN amplifies microglia-mediated neuroinflammation and exacerbates ischemic brain injury. J Neuroinflammation 2024; 21:35. [PMID: 38287411 PMCID: PMC10826034 DOI: 10.1186/s12974-024-03026-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/19/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Microglia is the major contributor of post-stroke neuroinflammation cascade and the crucial cellular target for the treatment of ischemic stroke. Currently, the endogenous mechanism underlying microglial activation following ischemic stroke remains elusive. Serglycin (SRGN) is a proteoglycan expressed in immune cells. Up to now, the role of SRGN on microglial activation and ischemic stroke is largely unexplored. METHODS Srgn knockout (KO), Cd44-KO and wild-type (WT) mice were subjected to middle cerebral artery occlusion (MCAO) to mimic ischemic stroke. Exogenous SRGN supplementation was achieved by stereotactic injection of recombinant mouse SRGN (rSRGN). Cerebral infarction was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Neurological functions were evaluated by the modified neurological severity score (mNSS) and grip strength. Microglial activation was detected by Iba1 immunostaining, morphological analysis and cytokines' production. Neuronal death was examined by MAP2 immunostaining and FJB staining. RESULTS The expression of SRGN and its receptor CD44 was significantly elevated in the ischemic mouse brains, especially in microglia. In addition, lipopolysaccharide (LPS) induced SRGN upregulation in microglia in vitro. rSRGN worsened ischemic brain injury in mice and amplified post-stroke neuroinflammation, while gene knockout of Srgn exerted reverse impacts. rSRGN promoted microglial proinflammatory activation both in vivo and in vitro, whereas Srgn-deficiency alleviated microglia-mediated inflammatory response. Moreover, the genetic deletion of Cd44 partially rescued rSRGN-induced excessed neuroinflammation and ischemic brain injury in mice. Mechanistically, SRGN boosted the activation of NF-κB signal, and increased glycolysis in microglia. CONCLUSION SRGN acts as a novel therapeutic target in microglia-boosted proinflammatory response following ischemic stroke.
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Affiliation(s)
- Yi Qian
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Lixuan Yang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Jian Chen
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Chao Zhou
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Ningning Zong
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Yang Geng
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Shengnan Xia
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Haiyan Yang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Xinyu Bao
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Yan Chen
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210008, China.
- Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China.
- Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210008, China.
- Jiangsu Provincial Key Discipline of Neurology, Nanjing, 210008, China.
- Nanjing Neurology Medical Center, Nanjing, 210008, China.
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Li H, Liu P, Zhang B, Yuan Z, Guo M, Zou X, Qian Y, Deng S, Zhu L, Cao X, Tao T, Xia S, Bao X, Xu Y. Acute ischemia induces spatially and transcriptionally distinct microglial subclusters. Genome Med 2023; 15:109. [PMID: 38082331 PMCID: PMC10712107 DOI: 10.1186/s13073-023-01257-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Damage in the ischemic core and penumbra after stroke affects patient prognosis. Microglia immediately respond to ischemic insult and initiate immune inflammation, playing an important role in the cellular injury after stroke. However, the microglial heterogeneity and the mechanisms involved remain unclear. METHODS We first performed single-cell RNA-sequencing (scRNA-seq) and spatial transcriptomics (ST) on middle cerebral artery occlusion (MCAO) mice from three time points to determine stroke-associated microglial subclusters and their spatial distributions. Furthermore, the expression of microglial subcluster-specific marker genes and the localization of different microglial subclusters were verified on MCAO mice through RNAscope and immunofluorescence. Gene set variation analysis (GSVA) was performed to reveal functional characteristics of microglia sub-clusters. Additionally, ingenuity pathway analysis (IPA) was used to explore upstream regulators of microglial subclusters, which was confirmed by immunofluorescence, RT-qPCR, shRNA-mediated knockdown, and targeted metabolomics. Finally, the infarct size, neurological deficits, and neuronal apoptosis were evaluated in MCAO mice after manipulation of specific microglial subcluster. RESULTS We discovered stroke-associated microglial subclusters in the brains of MCAO mice. We also identified novel marker genes of these microglial subclusters and defined these cells as ischemic core-associated (ICAM) and ischemic penumbra-associated (IPAM) microglia, according to their spatial distribution. ICAM, induced by damage-associated molecular patterns, are probably fueled by glycolysis, and exhibit increased pro-inflammatory cytokines and chemokines production. BACH1 is a key transcription factor driving ICAM generation. In contrast, glucocorticoids, which are enriched in the penumbra, likely trigger IPAM formation, which are presumably powered by the citrate cycle and oxidative phosphorylation and are characterized by moderate pro-inflammatory responses, inflammation-alleviating metabolic features, and myelinotrophic properties. CONCLUSIONS ICAM could induce excessive neuroinflammation, aggravating brain injury, whereas IPAM probably exhibit neuroprotective features, which could be essential for the homeostasis and survival of cells in the penumbra. Our findings provide a biological basis for targeting specific microglial subclusters as a potential therapeutic strategy for ischemic stroke.
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Affiliation(s)
- Huiya Li
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
- Department of Radiology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Pinyi Liu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Bing Zhang
- Department of Radiology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Zengqiang Yuan
- The Brain Science Centre, Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
- Centre of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, 100069, China
| | - Mengdi Guo
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Xinxin Zou
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Yi Qian
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Shiji Deng
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Liwen Zhu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Xiang Cao
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Tao Tao
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Shengnan Xia
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Xinyu Bao
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China
| | - Yun Xu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing, 210008, China.
- Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210008, China.
- Jiangsu Provincial Key Discipline of Neurology, Nanjing, 210008, China.
- Nanjing Neurology Medical Centre, Nanjing, 210008, China.
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