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López-Villodres JA, García-Díaz B. Oligodendroctyes: the forgotten players of diabetes pathophysiology. Neural Regen Res 2024; 19:2349-2350. [PMID: 38526269 PMCID: PMC11090424 DOI: 10.4103/nrr.nrr-d-23-01754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/06/2023] [Accepted: 12/24/2023] [Indexed: 03/26/2024] Open
Affiliation(s)
- Juan Antonio López-Villodres
- Departamento Fisiología Humana, Histología Humana, Anatomía Patológica y Educación Física y Deportiva, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - Beatriz García-Díaz
- UGC Neurociencia. Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina (IBIMA Plataforma Bionand), Málaga, Spain
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Seferi G, Mjønes HS, Havik M, Reiersen H, Dalen KT, Nordengen K, Morland C. Distribution of lipid droplets in hippocampal neurons and microglia: impact of diabetes and exercise. Life Sci Alliance 2024; 7:e202302239. [PMID: 39117458 PMCID: PMC11310565 DOI: 10.26508/lsa.202302239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/28/2024] [Accepted: 07/29/2024] [Indexed: 08/10/2024] Open
Abstract
Neuroinflammation, aging, and neurodegenerative disorders are associated with excessive accumulation of neutral lipids in lipid droplets (LDs) in microglia. Type 2 diabetes mellitus (T2DM) may cause neuroinflammation and is a risk factor for neurodegenerative disorders. Here, we show that hippocampal pyramidal neurons contain smaller, more abundant LDs than their neighboring microglia. The density of LDs varied between pyramidal cells in adjacent subregions, with CA3 neurons containing more LDs than CA1 neurons. Within the CA3 region, a gradual increase in the LD content along the pyramidal layer from the hilus toward CA2 was observed. Interestingly, the high neuronal LD content correlated with less ramified microglial morphotypes. Using the db/db model of T2DM, we demonstrated that diabetes increased the number of LDs per microglial cell without affecting the neuronal LD density. High-intensity interval exercise induced smaller changes in the number of LDs in microglia but was not sufficient to counteract the diabetes-induced changes in LD accumulation. The changes observed in response to T2DM may contribute to the cerebral effects of T2DM and provide a mechanistic link between T2DM and neurodegenerative disorders.
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Affiliation(s)
- Gezime Seferi
- https://ror.org/01xtthb56 Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Harald S Mjønes
- https://ror.org/01xtthb56 Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Mona Havik
- https://ror.org/01xtthb56 Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Herman Reiersen
- https://ror.org/01xtthb56 Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Knut Tomas Dalen
- https://ror.org/01xtthb56 Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kaja Nordengen
- Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Cecilie Morland
- https://ror.org/01xtthb56 Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
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3
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Wu M, Yu S, Yan S, Wu M, Zhang L, Chen S, Shi D, Liu S, Fan Y, Lin X, Shen J. Peroxynitrite reduces Treg cell expansion and function by mediating IL-2R nitration and aggravates multiple sclerosis pathogenesis. Redox Biol 2024; 75:103240. [PMID: 38889621 PMCID: PMC11231601 DOI: 10.1016/j.redox.2024.103240] [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: 03/23/2024] [Revised: 05/08/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024] Open
Abstract
T-helper 17 cells and regulatory T cells (Treg) are critical regulators in the pathogenesis of multiple sclerosis (MS) but the factors affecting Treg/Th17 balance remains largely unknown. Redox balance is crucial to maintaining immune homeostasis and reducing the severity of MS but the underlying mechanisms are unclear yet. Herein, we tested the hypothesis that peroxynitrite, a representative molecule of reactive nitrogen species (RNS), could inhibit peripheral Treg cells, disrupt Treg/Th17 balance and aggravate MS pathology by inducing nitration of interleukin-2 receptor (IL-2R) and down-regulating RAS/JNK-AP-1 signalling pathway. Experimental autoimmune encephalomyelitis (EAE) mouse model and serum samples of MS patients were used in the study. We found that the increases of 3-nitrotyrosine and IL-2R nitration in Treg cells were coincided with disease severity in the active EAE mice. Mechanistically, peroxynitrite-induced IL-2R nitration down-regulated RAS/JNK signalling pathway, subsequently impairing peripheral Treg expansion and function, increasing Teff infiltration into the central nerve system (CNS), aggravating demyelination and neurological deficits in the EAE mice. Those changes were abolished by peroxynitrite decomposition catalyst (PDC) treatment. Furthermore, transplantation of the PDC-treated-autologous Treg cells from donor EAE mice significantly decreased Th17 cells in both axillary lymph nodes and lumbar spinal cord, and ameliorated the neuropathology of the recipient EAE mice. Those results suggest that peroxynitrite could disrupt peripheral Treg/Th17 balance, and aggravate neuroinflammation and neurological deficit in active EAE/MS pathogenesis. The underlying mechanisms are related to induce the nitration of IL-2R and inhibit the RAS/JNK-AP-1 signalling pathway in Treg cells. The study highlights that targeting peroxynitrite-mediated peripheral IL-2R nitration in Treg cells could be a novel therapeutic strategy to restore Treg/Th17 balance and ameliorate MS/EAE pathogenesis. The study provides valuable insights into potential role of peripheral redox balance in maintaining CNS immune homeostasis.
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MESH Headings
- Peroxynitrous Acid/metabolism
- Animals
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Multiple Sclerosis/metabolism
- Multiple Sclerosis/immunology
- Mice
- Encephalomyelitis, Autoimmune, Experimental/metabolism
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Humans
- Receptors, Interleukin-2/metabolism
- Female
- Signal Transduction/drug effects
- Disease Models, Animal
- Th17 Cells/immunology
- Th17 Cells/metabolism
- Male
- Tyrosine/analogs & derivatives
- Tyrosine/metabolism
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Affiliation(s)
- Meiling Wu
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR 999077, China
| | - Sulan Yu
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China
| | - Shenyu Yan
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR 999077, China
| | - Minghui Wu
- Department of Traditional Chinese Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Lu Zhang
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR 999077, China
| | - Shuang Chen
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR 999077, China
| | - Dongyun Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200000, China
| | - Shanlin Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200000, China; Free Radical Regulation and Application Research Center of Fudan University, Shanghai, 200000, China
| | - Yongping Fan
- Department of Traditional Chinese Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Xiang Lin
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR 999077, China.
| | - Jiangang Shen
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR 999077, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR 999077, China.
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Xing Y, Ma X, Zhai R, Chen W, Yan H. GDF11 improves hippocampal neurogenesis and cognitive abilities in diabetic mice by reducing neural inflammation. Brain Behav Immun 2024; 120:21-31. [PMID: 38777287 DOI: 10.1016/j.bbi.2024.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/02/2024] [Accepted: 05/19/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND The cognitive decline associated with type 2 diabetes (T2D) is often attributed to compromised hippocampal neurogenesis and exacerbated neural inflammation. This study investigates the therapeutic potential of growth differentiation factor 11 (GDF11) in reversing these neurodegenerative processes in diabetic mice. RESULT We utilized a murine model of T2D and examined the effects of GDF11 on learning, memory, neurogenesis, and neuroinflammatory markers. Our results indicate that diabetic mice exhibit significant deficits in cognitive function, mirrored by reduced hippocampal neurogenesis and increased neuroinflammation. Chronic administration of GDF11 was observed to significantly enhance cognitive abilities, as evidenced by improved performance in learning and memory tasks. Concurrently, GDF11 treatment restored neural activity and promoted the regeneration of new neurons within the hippocampus. Inflammatory profiling revealed a reduction in neuroinflammatory markers, which was further supported by reduced microglia numbers. To delineate the role of neuroinflammation, we pharmacologically depleted microglia, leading to a restoration of neurogenesis and cognitive functions in diabetic mice. CONCLUSION These findings endorse the hypothesis that GDF11 exerts its beneficial effects by modulating neuroinflammatory pathways. Consequently, GDF11 represents a promising intervention to ameliorate diabetes-induced cognitive impairments and neural degeneration through its anti-inflammatory properties.
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Affiliation(s)
- Yao Xing
- School of Information Science and Technology, Fudan University, Shanghai 200433, PR China; Wuhan United Imaging Life Science Instrument Co., Ltd., Wuhan 430206, PR China
| | - Xiaoyi Ma
- Department of Geriatrics, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, PR China
| | - Renkuan Zhai
- Wuhan United Imaging Life Science Instrument Co., Ltd., Wuhan 430206, PR China
| | - Wei Chen
- School of Information Science and Technology, Fudan University, Shanghai 200433, PR China; Human Phenome Institute, Fudan University, 825 Zhangheng Road, Shanghai 201203, PR China.
| | - Huanhuan Yan
- Shenzhen United Imaging Research Institute of Innovative Medical Equipment, Shenzhen 518048, PR China.
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Zhang WY, Wei QQ, Zhang T, Wang CS, Chen J, Wang JH, Xie X, Jiang P. Microglial AKAP8L: a key mediator in diabetes-associated cognitive impairment via autophagy inhibition and neuroinflammation triggering. J Neuroinflammation 2024; 21:177. [PMID: 39033121 PMCID: PMC11264944 DOI: 10.1186/s12974-024-03170-z] [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: 04/24/2024] [Accepted: 07/09/2024] [Indexed: 07/23/2024] Open
Abstract
BACKGROUND Diabetes-associated cognitive impairment (DACI) poses a significant challenge to the self-management of diabetes, markedly elevating the risk of adverse complications. A burgeoning body of evidence implicates microglia as a central player in the pathogenesis of DACI. METHODS We utilized proteomics to identify potential biomarkers in high glucose (HG)-treated microglia, followed by gene knockdown techniques for mechanistic validation in vitro and in vivo. RESULTS Our proteomic analysis identified a significant upregulation of AKAP8L in HG-treated microglia, with concurrent dysregulation of autophagy and inflammation markers, making AKAP8L a novel biomarker of interest. Notably, the accumulation of AKAP8L was specific to HG-treated microglia, with no observed changes in co-cultured astrocytes or neurons, a pattern that was mirrored in streptozotocin (STZ)-induced diabetic mice. Further studies through co-immunoprecipitation and proximity ligation assay indicated that the elevated AKAP8L in HG-treated microglial cells interacts with the mTORC1. In the STZ mouse model, we demonstrated that both AKAP8L knockdown and rapamycin treatment significantly enhanced cognitive function, as evidenced by improved performance in the Morris water maze, and reduced microglial activation. Moreover, these interventions effectively suppressed mTORC1 signaling, normalized autophagic flux, mitigated neuroinflammation, and decreased pyroptosis. CONCLUSIONS Our findings highlight the critical role of AKAP8L in the development of DACI. By interacting with mTORC1, AKAP8L appears to obstruct autophagic processes and initiate a cascade of neuroinflammatory responses. The identification of AKAP8L as a key mediator in DACI opens up new avenues for potential therapeutic interventions.
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Affiliation(s)
- Wen-Yuan Zhang
- Department of Pharmacy, Zhongshan City People's Hospital, Zhongshan, 528403, China
- School of Pharmaceutical Sciences, Zunyi Medical University, Zunyi, 510006, China
| | - Qian-Qian Wei
- Department of Pharmacy, Zhongshan City People's Hospital, Zhongshan, 528403, China
- School of Pharmaceutical Sciences, Zunyi Medical University, Zunyi, 510006, China
| | - Tao Zhang
- Translational Pharmaceutical Laboratory, Jining First People ' s Hospital, Shandong First Medical University, Jining, 272000, China
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, 272000, China
| | - Chang-Shui Wang
- Department of Neurosurgery, Affiliated Hospital of Jining Medical University, Jining, 272000, China
| | - Jing Chen
- Neurobiology Key Laboratory, Jining Medical University, Jining, 272067, China
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
| | - Jian-Hua Wang
- Translational Pharmaceutical Laboratory, Jining First People ' s Hospital, Shandong First Medical University, Jining, 272000, China
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, 272000, China
| | - Xin Xie
- Translational Pharmaceutical Laboratory, Jining First People ' s Hospital, Shandong First Medical University, Jining, 272000, China
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, 272000, China
| | - Pei Jiang
- Translational Pharmaceutical Laboratory, Jining First People ' s Hospital, Shandong First Medical University, Jining, 272000, China.
- Institute of Translational Pharmacy, Jining Medical Research Academy, Jining, 272000, China.
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Wątroba M, Grabowska AD, Szukiewicz D. Chemokine CX3CL1 (Fractalkine) Signaling and Diabetic Encephalopathy. Int J Mol Sci 2024; 25:7527. [PMID: 39062768 PMCID: PMC11277241 DOI: 10.3390/ijms25147527] [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: 05/31/2024] [Revised: 07/04/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Diabetes mellitus (DM) is the most common metabolic disease in humans, and its prevalence is increasing worldwide in parallel with the obesity pandemic. A lack of insulin or insulin resistance, and consequently hyperglycemia, leads to many systemic disorders, among which diabetic encephalopathy (DE) is a long-term complication of the central nervous system (CNS), characterized by cognitive impairment and motor dysfunctions. The role of oxidative stress and neuroinflammation in the pathomechanism of DE has been proven. Fractalkine (CX3CL1) has unique properties as an adhesion molecule and chemoattractant, and by acting on its only receptor, CX3CR1, it regulates the activity of microglia in physiological states and neuroinflammation. Depending on the clinical context, CX3CL1-CX3CR1 signaling may have neuroprotective effects by inhibiting the inflammatory process in microglia or, conversely, maintaining/intensifying inflammation and neurotoxicity. This review discusses the evidence supporting that the CX3CL1-CX3CR1 pair is neuroprotective and other evidence that it is neurotoxic. Therefore, interrupting the vicious cycle within neuron-microglia interactions by promoting neuroprotective effects or inhibiting the neurotoxic effects of the CX3CL1-CX3CR1 signaling axis may be a therapeutic goal in DE by limiting the inflammatory response. However, the optimal approach to prevent DE is simply tight glycemic control, because the elimination of dysglycemic states in the CNS abolishes the fundamental mechanisms that induce this vicious cycle.
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Affiliation(s)
| | | | - Dariusz Szukiewicz
- Laboratory of the Blood-Brain Barrier, Department of Biophysics, Physiology & Pathophysiology, Medical University of Warsaw, Chałubińskiego 5, 02-400 Warsaw, Poland; (M.W.); (A.D.G.)
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7
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Serrano-Marín J, Valenzuela R, Delgado C, Quijano A, Navarro G, Luis Labandeira-García J, Franco R. Neuroprotective compounds alter the expression of genes coding for proteins related to mitochondrial function in activated microglia. Mitochondrion 2024; 78:101934. [PMID: 38992856 DOI: 10.1016/j.mito.2024.101934] [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: 07/24/2023] [Revised: 06/24/2024] [Accepted: 07/08/2024] [Indexed: 07/13/2024]
Abstract
A hallmark of neuroinflammatory disorders is mitochondrial dysfunction. Nevertheless, the transcriptional changes underlying this alteration are not well-defined. Microglia activation, a decrease in mitochondrion biogenesis and a subsequent alteration of the redox are common factors in diseases coursing with neuroinflammation. In the last two decades, components of the adenosinergic system have been proposed as potential therapeutic targets to combat neuroinflammation. In this research, we analyzed by RNAseq the gene expression in activated microglia treated with an adenosine A2A receptor antagonist, SCH 582561, and/or an A3 receptor agonist, 2-Cl-IB-MECA, since these receptors are deeply related to neurodegeneration and inflammation. The analysis was focused on genes related to inflammation and REDOX homeostasis. It was detected that in the three conditions (microglia treated with 2-Cl-IB-MECA, SCH 582561, and their combination) more than 40 % of the detected genes codified by the mitochondrial genome were differentially expressed (FDR < 0.05) (14/34, 16/34, and 13/34) respectively, being almost all of them (>85 %) upregulated in the microglia treated with adenosinergic compounds. Also, we analyzed the differential expression of genes related to mitochondrial function and oxidative stress codified by the nuclear genome. Additionally, we evaluated the oxygen consumption rate (OCR) of mitochondria in microglia treated with LPS and IFN-γ, both alone and in combination with adenosinergic compounds. The data showed an improvement in mitochondrial function with the antagonist of the adenosine A2A receptor, compared to the effects of pro-inflammatory stimulus, confirming a functional effect consistent with the RNAseq data.
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Affiliation(s)
- Joan Serrano-Marín
- Molecular Neurobiology laboratory. Department of Biochemistry and Molecular Biomedicine, Faculty of Biology. Universitat de Barcelona. Barcelona. Spain
| | - Rita Valenzuela
- CIMUS, University of Santiago de Compostela. IDIS (Heath Reserch Institute), Santiago de Compostela, Spain; CiberNed. Network Center for Neurodegenerative diseases. National Spanish Health Institute Carlos III. Madrid. Spain
| | - Cristina Delgado
- Molecular Neurobiology laboratory. Department of Biochemistry and Molecular Biomedicine, Faculty of Biology. Universitat de Barcelona. Barcelona. Spain
| | - Aloia Quijano
- CIMUS, University of Santiago de Compostela. IDIS (Heath Reserch Institute), Santiago de Compostela, Spain; CiberNed. Network Center for Neurodegenerative diseases. National Spanish Health Institute Carlos III. Madrid. Spain
| | - Gemma Navarro
- CiberNed. Network Center for Neurodegenerative diseases. National Spanish Health Institute Carlos III. Madrid. Spain; Department of Biochemistry and Physiology. School of Pharmacy and Food Sciences. Universitat de Barcelona. Barcelona. Spain; Institute of Neurosciences. Universitat de Barcelona. Barcelona. Spain.
| | - José Luis Labandeira-García
- CIMUS, University of Santiago de Compostela. IDIS (Heath Reserch Institute), Santiago de Compostela, Spain; CiberNed. Network Center for Neurodegenerative diseases. National Spanish Health Institute Carlos III. Madrid. Spain
| | - Rafael Franco
- Molecular Neurobiology laboratory. Department of Biochemistry and Molecular Biomedicine, Faculty of Biology. Universitat de Barcelona. Barcelona. Spain; CiberNed. Network Center for Neurodegenerative diseases. National Spanish Health Institute Carlos III. Madrid. Spain; School of Chemistry. Universitat de Barcelona. Barcelona. Spain.
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8
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Deshmukh H, Santos JM, Bender M, Dufour JM, Lovett J, Shen CL. Peanut Shell Extract Improves Mitochondrial Function in db/db Mice via Suppression of Oxidative Stress and Inflammation. Nutrients 2024; 16:1977. [PMID: 38999726 PMCID: PMC11243022 DOI: 10.3390/nu16131977] [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: 05/10/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 07/14/2024] Open
Abstract
Accumulating evidence shows a strong correlation between type 2 diabetes mellitus, mitochondrial dysfunction, and oxidative stress. We evaluated the effects of dietary peanut shell extract (PSE) supplementation on mitochondrial function and antioxidative stress/inflammation markers in diabetic mice. Fourteen db/db mice were randomly assigned to a diabetic group (DM in AIN-93G diet) and a PSE group (1% wt/wt PSE in AIN-93G diet) for 5 weeks. Six C57BL/6J mice were fed with an AIN-93G diet for 5 weeks (control group). Gene and protein expression in the liver, brain, and white adipose tissue (WAT) were determined using qRT-PCR and Immunoblot, respectively. Compared to the control group, the DM group had (i) increased gene and protein expression levels of DRP1 (fission), PINK1 (mitophagy), and TNFα (inflammation) and (ii) decreased gene and protein expression levels of MFN1, MFN2, OPA1 (fusion), TFAM, PGC-1α (biogenesis), NRF2 (antioxidative stress) and IBA1 (microglial activation) in the liver, brain, and WAT of db/db mice. Supplementation of PSE into the diet restored the DM-induced changes in the gene and protein expression of DRP1, PINK1, TNFα, MFN1, MFN2, OPA1, TFAM, PGC-1α, NRF2, and IBA1 in the liver, brain, and WAT of db/db mice. This study demonstrates that PSE supplementation improved mitochondrial function in the brain, liver, and WAT of db/db mice, in part due to suppression of oxidative stress and inflammation.
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Affiliation(s)
- Hemalata Deshmukh
- Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (H.D.); (J.M.S.); (J.L.)
| | - Julianna M. Santos
- Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (H.D.); (J.M.S.); (J.L.)
| | - Matthew Bender
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (M.B.); (J.M.D.)
| | - Jannette M. Dufour
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (M.B.); (J.M.D.)
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Center of Excellence for Integrative Health, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Obesity Research Institute, Texas Tech University, Lubbock, TX 79401, USA
| | - Jacob Lovett
- Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (H.D.); (J.M.S.); (J.L.)
| | - Chwan-Li Shen
- Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (H.D.); (J.M.S.); (J.L.)
- Center of Excellence for Integrative Health, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Obesity Research Institute, Texas Tech University, Lubbock, TX 79401, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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9
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Cai L, Xia M, Zhang F. Redox Regulation of Immunometabolism in Microglia Underpinning Diabetic Retinopathy. Antioxidants (Basel) 2024; 13:423. [PMID: 38671871 PMCID: PMC11047590 DOI: 10.3390/antiox13040423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/24/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Diabetic retinopathy (DR) is the leading cause of visual impairment and blindness among the working-age population. Microglia, resident immune cells in the retina, are recognized as crucial drivers in the DR process. Microglia activation is a tightly regulated immunometabolic process. In the early stages of DR, the M1 phenotype commonly shifts from oxidative phosphorylation to aerobic glycolysis for energy production. Emerging evidence suggests that microglia in DR not only engage specific metabolic pathways but also rearrange their oxidation-reduction (redox) system. This redox adaptation supports metabolic reprogramming and offers potential therapeutic strategies using antioxidants. Here, we provide an overview of recent insights into the involvement of reactive oxygen species and the distinct roles played by key cellular antioxidant pathways, including the NADPH oxidase 2 system, which promotes glycolysis via enhanced glucose transporter 4 translocation to the cell membrane through the AKT/mTOR pathway, as well as the involvement of the thioredoxin and nuclear factor E2-related factor 2 antioxidant systems, which maintain microglia in an anti-inflammatory state. Therefore, we highlight the potential for targeting the modulation of microglial redox metabolism to offer new concepts for DR treatment.
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Affiliation(s)
- Luwei Cai
- National Clinical Research Center for Eye Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; (L.C.); (M.X.)
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Mengxue Xia
- National Clinical Research Center for Eye Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; (L.C.); (M.X.)
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
| | - Fang Zhang
- National Clinical Research Center for Eye Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; (L.C.); (M.X.)
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai 200080, China
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10
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Ji S, Peng Y, Liu J, Xu P, Tang S. Human adipose tissue-derived stem cell extracellular vesicles attenuate ocular hypertension-induced retinal ganglion cell damage by inhibiting microglia- TLR4/MAPK/NF-κB proinflammatory cascade signaling. Acta Neuropathol Commun 2024; 12:44. [PMID: 38504301 PMCID: PMC10953184 DOI: 10.1186/s40478-024-01753-8] [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: 01/22/2024] [Accepted: 03/07/2024] [Indexed: 03/21/2024] Open
Abstract
Microglia-mediated neuroinflammatory responses are recognized as a predominant factor during high intraocular pressure (IOP)-induced retinal and optic nerve injury along with potential therapeutic targets for the disease. Our previous research indicated that mesenchymal stem cell (MSC) treatment could reduce high IOP-induced neuroinflammatory responses through the TLR4 pathway in a rat model without apparent cell replacement and differentiation, suggesting that the anti-neuroinflammatory properties of MSCs are potentially mediated by paracrine signaling. This study aimed to evaluate the anti-neuroinflammatory effect of human adipose tissue-derived extracellular vesicles (ADSC-EVs) in microbead-induced ocular hypertension (OHT) animals and to explore the underlying mechanism since extracellular vesicles (EVs) are the primary transporters for cell secretory action. The anti-neuroinflammatory effect of ADSC-EVs on LPS-stimulated BV-2 cells in vitro and OHT-induced retinal and optic nerve injury in vivo was investigated. According to the in vitro research, ADSC-EV treatment reduced LPS-induced microglial activation and the TLR4/NF-κB proinflammatory cascade response axis in BV-2 cells, such as CD68, iNOS, TNF-α, IL-6, and IL-1β, TLR4, p-38 MAPK, NF-κB. According to the in vivo data, intravitreal injection of ADSC-EVs promoted RGC survival and function, reduced microglial activation, microglial-derived neuroinflammatory responses, and TLR4/MAPK/NF-κB proinflammatory cascade response axis in the OHT mice. Our findings provide preliminary evidence for the RGC protective and microglia-associated neuroinflammatory reduction effects of ADSC-EVs by inhibiting the TLR4/MAPK/NF-κB proinflammatory cascade response in OHT mice, indicating the therapeutic potential ADSC-EVs or adjunctive therapy for glaucoma.
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Affiliation(s)
- Shangli Ji
- Aier Eye Hospital, Jinan University, 510632, Guangzhou, Guangdong, China
- Guangzhou Aier Eye Hospital, 510010, Guangzhou, Guangdong, China
| | - Yanfang Peng
- Aier Eye Institute, 410015, Changsha, Hunan, China
| | - Jian Liu
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, 410011, Changsha, Hunan, China
| | - Pang Xu
- Aier Eye Hospital, Jinan University, 510632, Guangzhou, Guangdong, China
| | - Shibo Tang
- Aier Eye Hospital, Jinan University, 510632, Guangzhou, Guangdong, China.
- Guangzhou Aier Eye Hospital, 510010, Guangzhou, Guangdong, China.
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11
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Llorián-Salvador M, Cabeza-Fernández S, Gomez-Sanchez JA, de la Fuente AG. Glial cell alterations in diabetes-induced neurodegeneration. Cell Mol Life Sci 2024; 81:47. [PMID: 38236305 PMCID: PMC10796438 DOI: 10.1007/s00018-023-05024-y] [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: 08/20/2023] [Revised: 10/09/2023] [Accepted: 10/29/2023] [Indexed: 01/19/2024]
Abstract
Type 2 diabetes mellitus is a global epidemic that due to its increasing prevalence worldwide will likely become the most common debilitating health condition. Even if diabetes is primarily a metabolic disorder, it is now well established that key aspects of the pathogenesis of diabetes are associated with nervous system alterations, including deleterious chronic inflammation of neural tissues, referred here as neuroinflammation, along with different detrimental glial cell responses to stress conditions and neurodegenerative features. Moreover, diabetes resembles accelerated aging, further increasing the risk of developing age-linked neurodegenerative disorders. As such, the most common and disabling diabetic comorbidities, namely diabetic retinopathy, peripheral neuropathy, and cognitive decline, are intimately associated with neurodegeneration. As described in aging and other neurological disorders, glial cell alterations such as microglial, astrocyte, and Müller cell increased reactivity and dysfunctionality, myelin loss and Schwann cell alterations have been broadly described in diabetes in both human and animal models, where they are key contributors to chronic noxious inflammation of neural tissues within the PNS and CNS. In this review, we aim to describe in-depth the common and unique aspects underlying glial cell changes observed across the three main diabetic complications, with the goal of uncovering shared glial cells alterations and common pathological mechanisms that will enable the discovery of potential targets to limit neuroinflammation and prevent neurodegeneration in all three diabetic complications. Diabetes and its complications are already a public health concern due to its rapidly increasing incidence, and thus its health and economic impact. Hence, understanding the key role that glial cells play in the pathogenesis underlying peripheral neuropathy, retinopathy, and cognitive decline in diabetes will provide us with novel therapeutic approaches to tackle diabetic-associated neurodegeneration.
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Affiliation(s)
- María Llorián-Salvador
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University, Belfast, UK.
| | - Sonia Cabeza-Fernández
- Institute for Health and Biomedical Research of Alicante (ISABIAL), Alicante, Spain
- Institute of Neuroscience CSIC-UMH, San Juan de Alicante, Spain
| | - Jose A Gomez-Sanchez
- Institute for Health and Biomedical Research of Alicante (ISABIAL), Alicante, Spain
- Institute of Neuroscience CSIC-UMH, San Juan de Alicante, Spain
| | - Alerie G de la Fuente
- Institute for Health and Biomedical Research of Alicante (ISABIAL), Alicante, Spain.
- Institute of Neuroscience CSIC-UMH, San Juan de Alicante, Spain.
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12
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Zhu J, Hu Z, Luo Y, Liu Y, Luo W, Du X, Luo Z, Hu J, Peng S. Diabetic peripheral neuropathy: pathogenetic mechanisms and treatment. Front Endocrinol (Lausanne) 2024; 14:1265372. [PMID: 38264279 PMCID: PMC10803883 DOI: 10.3389/fendo.2023.1265372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 12/14/2023] [Indexed: 01/25/2024] Open
Abstract
Diabetic peripheral neuropathy (DPN) refers to the development of peripheral nerve dysfunction in patients with diabetes when other causes are excluded. Diabetic distal symmetric polyneuropathy (DSPN) is the most representative form of DPN. As one of the most common complications of diabetes, its prevalence increases with the duration of diabetes. 10-15% of newly diagnosed T2DM patients have DSPN, and the prevalence can exceed 50% in patients with diabetes for more than 10 years. Bilateral limb pain, numbness, and paresthesia are the most common clinical manifestations in patients with DPN, and in severe cases, foot ulcers can occur, even leading to amputation. The etiology and pathogenesis of diabetic neuropathy are not yet completely clarified, but hyperglycemia, disorders of lipid metabolism, and abnormalities in insulin signaling pathways are currently considered to be the initiating factors for a range of pathophysiological changes in DPN. In the presence of abnormal metabolic factors, the normal structure and function of the entire peripheral nervous system are disrupted, including myelinated and unmyelinated nerve axons, perikaryon, neurovascular, and glial cells. In addition, abnormalities in the insulin signaling pathway will inhibit neural axon repair and promote apoptosis of damaged cells. Here, we will discuss recent advances in the study of DPN mechanisms, including oxidative stress pathways, mechanisms of microvascular damage, mechanisms of damage to insulin receptor signaling pathways, and other potential mechanisms associated with neuroinflammation, mitochondrial dysfunction, and cellular oxidative damage. Identifying the contributions from each pathway to neuropathy and the associations between them may help us to further explore more targeted screening and treatment interventions.
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Affiliation(s)
- Jinxi Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Ziyan Hu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yifan Luo
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yinuo Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Wei Luo
- Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaohong Du
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Zhenzhong Luo
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jialing Hu
- Department of Emergency Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Shengliang Peng
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
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13
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Sood A, Fernandes V, Preeti K, Rajan S, Khatri DK, Singh SB. S1PR2 inhibition mitigates cognitive deficit in diabetic mice by modulating microglial activation via Akt-p53-TIGAR pathway. Int Immunopharmacol 2024; 126:111278. [PMID: 38011768 DOI: 10.1016/j.intimp.2023.111278] [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: 09/21/2023] [Revised: 11/07/2023] [Accepted: 11/20/2023] [Indexed: 11/29/2023]
Abstract
Cognitive deficit is one of the challenging complications of type 2 diabetes. Sphingosine 1- phosphate receptors (S1PRs) have been implicated in various neurodegenerative and metabolic disorders. The association of S1PRs and cognition in type 2 diabetes remains elusive. Microglia-mediated neuronal damage could be the thread propagating cognitive deficit. The effects of S1PR2 inhibition on cognition in high-fat diet and streptozotocin-induced diabetic mice were examined in this work. We further assessed microglial activation and putative microglial polarisation routes. Cognitive function loss was observed after four months of diabetes induction in Type 2 diabetes animal model. JTE013, an S1PR2 inhibitor, was used to assess neuroprotection against cognitive decline and neuroinflammation in vitro and in vivo diabetes model. JTE013 (10 mg/kg) improved synaptic plasticity by upregulating psd95 and synaptophysin while reducing cognitive decline and neuroinflammation. It further enhanced anti-inflammatory microglia in the hippocampus and prefrontal cortex (PFC), as evidenced by increased Arg-1, CD206, and YM-1 levels and decreased iNOS, CD16, and MHCII levels. TIGAR, TP53-induced glycolysis and apoptosis regulator, might facilitate the anti-inflammatory microglial phenotype by promoting oxidative phosphorylation and decreasing apoptosis. However, since p53 is a TIGAR suppressor, inhibiting p53 could be beneficial. S1PR2 inhibition increased p-Akt and TIGAR levels and reduced the levels of p53 in the PFC and hippocampus of type 2 diabetic mice, thereby decreasing apoptosis. In vitro, palmitate was used to imitate sphingolipid dysregulation in BV2 cells, followed by conditioned media exposure to Neuro2A cells. JTE013 rescued the palmitate-induced neuronal apoptosis by promoting the anti-inflammatory microglia. In the present study, we demonstrate that the inhibition of S1PR2 improves cognitive function and skews microglia toward anti-inflammatory phenotype in type 2 diabetic mice, thereby promising to be a potential therapy for neuroinflammation.
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Affiliation(s)
- Anika Sood
- Department of Pharmacology and Toxicology, NIPER Hyderabad, Hyderabad, Telangana 500037, India
| | - Valencia Fernandes
- Department of Pharmacology and Toxicology, NIPER Hyderabad, Hyderabad, Telangana 500037, India
| | - Kumari Preeti
- Department of Pharmacology and Toxicology, NIPER Hyderabad, Hyderabad, Telangana 500037, India
| | - Shruti Rajan
- Department of Pharmacology and Toxicology, NIPER Hyderabad, Hyderabad, Telangana 500037, India
| | - Dharmendra Kumar Khatri
- Department of Pharmacology and Toxicology, NIPER Hyderabad, Hyderabad, Telangana 500037, India.
| | - Shashi Bala Singh
- Department of Pharmacology and Toxicology, NIPER Hyderabad, Hyderabad, Telangana 500037, India.
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14
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Weaver DF. Thirty Risk Factors for Alzheimer's Disease Unified by a Common Neuroimmune-Neuroinflammation Mechanism. Brain Sci 2023; 14:41. [PMID: 38248256 PMCID: PMC10813027 DOI: 10.3390/brainsci14010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/27/2023] [Accepted: 12/30/2023] [Indexed: 01/23/2024] Open
Abstract
One of the major obstacles confronting the formulation of a mechanistic understanding for Alzheimer's disease (AD) is its immense complexity-a complexity that traverses the full structural and phenomenological spectrum, including molecular, macromolecular, cellular, neurological and behavioural processes. This complexity is reflected by the equally complex diversity of risk factors associated with AD. However, more than merely mirroring disease complexity, risk factors also provide fundamental insights into the aetiology and pathogenesis of AD as a neurodegenerative disorder since they are central to disease initiation and subsequent propagation. Based on a systematic literature assessment, this review identified 30 risk factors for AD and then extended the analysis to further identify neuroinflammation as a unifying mechanism present in all 30 risk factors. Although other mechanisms (e.g., vasculopathy, proteopathy) were present in multiple risk factors, dysfunction of the neuroimmune-neuroinflammation axis was uniquely central to all 30 identified risk factors. Though the nature of the neuroinflammatory involvement varied, the activation of microglia and the release of pro-inflammatory cytokines were a common pathway shared by all risk factors. This observation provides further evidence for the importance of immunopathic mechanisms in the aetiopathogenesis of AD.
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Affiliation(s)
- Donald F Weaver
- Krembil Research Institute, University Health Network, Departments of Medicine, Chemistry, Pharmaceutical Sciences, University of Toronto, Toronto, ON M5T 0S8, Canada
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15
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Horvat A, Vlašić I, Štefulj J, Oršolić N, Jazvinšćak Jembrek M. Flavonols as a Potential Pharmacological Intervention for Alleviating Cognitive Decline in Diabetes: Evidence from Preclinical Studies. Life (Basel) 2023; 13:2291. [PMID: 38137892 PMCID: PMC10744738 DOI: 10.3390/life13122291] [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: 09/30/2023] [Revised: 11/15/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Diabetes mellitus is a complex metabolic disease associated with reduced synaptic plasticity, atrophy of the hippocampus, and cognitive decline. Cognitive impairment results from several pathological mechanisms, including increased levels of advanced glycation end products (AGEs) and their receptors, prolonged oxidative stress and impaired activity of endogenous mechanisms of antioxidant defense, neuroinflammation driven by the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), decreased expression of brain-derived neurotrophic factor (BDNF), and disturbance of signaling pathways involved in neuronal survival and cognitive functioning. There is increasing evidence that dietary interventions can reduce the risk of various diabetic complications. In this context, flavonols, a highly abundant class of flavonoids in the human diet, are appreciated as a potential pharmacological intervention against cognitive decline in diabetes. In preclinical studies, flavonols have shown neuroprotective, antioxidative, anti-inflammatory, and memory-enhancing properties based on their ability to regulate glucose levels, attenuate oxidative stress and inflammation, promote the expression of neurotrophic factors, and regulate signaling pathways. The present review gives an overview of the molecular mechanisms involved in diabetes-induced cognitive dysfunctions and the results of preclinical studies showing that flavonols have the ability to alleviate cognitive impairment. Although the results from animal studies are promising, clinical and epidemiological studies are still needed to advance our knowledge on the potential of flavonols to improve cognitive decline in diabetic patients.
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Affiliation(s)
- Anđela Horvat
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Ignacija Vlašić
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Jasminka Štefulj
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
- Department of Psychology, Catholic University of Croatia, Ilica 242, 10000 Zagreb, Croatia
| | - Nada Oršolić
- Division of Animal Physiology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia
| | - Maja Jazvinšćak Jembrek
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
- Department of Psychology, Catholic University of Croatia, Ilica 242, 10000 Zagreb, Croatia
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16
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Majimbi M, McLenachan S, Nesbit M, Chen FK, Lam V, Mamo J, Takechi R. In vivo retinal imaging is associated with cognitive decline, blood-brain barrier disruption and neuroinflammation in type 2 diabetic mice. Front Endocrinol (Lausanne) 2023; 14:1224418. [PMID: 37850093 PMCID: PMC10577437 DOI: 10.3389/fendo.2023.1224418] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/15/2023] [Indexed: 10/19/2023] Open
Abstract
Introduction Type 2 diabetes (T2D) is associated with chronic inflammation and neurovascular changes that lead to functional impairment and atrophy in neural-derived tissue. A reduction in retinal thickness is an early indicator of diabetic retinopathy (DR), with progressive loss of neuroglia corresponding to DR severity. The brain undergoes similar pathophysiological events as the retina, which contribute to T2D-related cognitive decline. Methods This study explored the relationship between retinal thinning and cognitive decline in the LepR db/db model of T2D. Diabetic db/db and non-diabetic db/+ mice aged 14 and 28 weeks underwent cognitive testing in short and long-term memory domains and in vivo retinal imaging using optical coherence tomography (OCT), followed by plasma metabolic measures and ex vivo quantification of neuroinflammation, oxidative stress and microvascular leakage. Results At 28 weeks, mice exhibited retinal thinning in the ganglion cell complex and inner nuclear layer, concomitant with diabetic insulin resistance, memory deficits, increased expression of inflammation markers and cerebrovascular leakage. Interestingly, alterations in retinal thickness at both experimental timepoints were correlated with cognitive decline and elevated immune response in the brain and retina. Discussion These results suggest that changes in retinal thickness quantified with in vivo OCT imaging may be an indicator of diabetic cognitive dysfunction and neuroinflammation.
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Affiliation(s)
- May Majimbi
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
| | - Samuel McLenachan
- Lions Eye Institute Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
| | - Michael Nesbit
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
| | - Fred K. Chen
- Lions Eye Institute Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
| | - Virginie Lam
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
| | - John Mamo
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
- Perron Institute for Neurological and Translational Research, Nedlands, WA, Australia
| | - Ryu Takechi
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
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17
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Mukherjee S, Skrede S, Haugstøyl M, López M, Fernø J. Peripheral and central macrophages in obesity. Front Endocrinol (Lausanne) 2023; 14:1232171. [PMID: 37720534 PMCID: PMC10501731 DOI: 10.3389/fendo.2023.1232171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/28/2023] [Indexed: 09/19/2023] Open
Abstract
Obesity is associated with chronic, low-grade inflammation. Excessive nutrient intake causes adipose tissue expansion, which may in turn cause cellular stress that triggers infiltration of pro-inflammatory immune cells from the circulation as well as activation of cells that are residing in the adipose tissue. In particular, the adipose tissue macrophages (ATMs) are important in the pathogenesis of obesity. A pro-inflammatory activation is also found in other organs which are important for energy metabolism, such as the liver, muscle and the pancreas, which may stimulate the development of obesity-related co-morbidities, including insulin resistance, type 2 diabetes (T2D), cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). Interestingly, it is now clear that obesity-induced pro-inflammatory signaling also occurs in the central nervous system (CNS), and that pro-inflammatory activation of immune cells in the brain may be involved in appetite dysregulation and metabolic disturbances in obesity. More recently, it has become evident that microglia, the resident macrophages of the CNS that drive neuroinflammation, may also be activated in obesity and can be relevant for regulation of hypothalamic feeding circuits. In this review, we focus on the action of peripheral and central macrophages and their potential roles in metabolic disease, and how macrophages interact with other immune cells to promote inflammation during obesity.
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Affiliation(s)
- Sayani Mukherjee
- Hormone Laboratory, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - Silje Skrede
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
- Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
| | - Martha Haugstøyl
- Hormone Laboratory, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - Johan Fernø
- Hormone Laboratory, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway
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18
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Iwasa M, Kato H, Iwashita K, Yamakage H, Kato S, Saito S, Ihara M, Nishimura H, Kawamoto A, Suganami T, Tanaka M, Satoh-Asahara N. Taxifolin Suppresses Inflammatory Responses of High-Glucose-Stimulated Mouse Microglia by Attenuating the TXNIP-NLRP3 Axis. Nutrients 2023; 15:2738. [PMID: 37375642 DOI: 10.3390/nu15122738] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
Type 2 diabetes mellitus is associated with an increased risk of dementia, potentially through multifactorial pathologies, including neuroinflammation. Therefore, there is a need to identify novel agents that can suppress neuroinflammation and prevent cognitive impairment in diabetes. In the present study, we demonstrated that a high-glucose (HG) environment elevates the intracellular reactive oxygen species (ROS) levels and triggers inflammatory responses in the mouse microglial cell line BV-2. We further found that thioredoxin-interacting protein (TXNIP), a ROS-responsive positive regulator of the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, was also upregulated, followed by NLRP3 inflammasome activation and subsequent interleukin-1beta (IL-1β) production in these cells. Conversely, caspase-1 was not significantly activated, suggesting the involvement of noncanonical pathways in these inflammatory responses. Moreover, our results demonstrated that taxifolin, a natural flavonoid with antioxidant and radical scavenging activities, suppressed IL-1β production by reducing the intracellular ROS levels and inhibiting the activation of the TXNIP-NLRP3 axis. These findings suggest the novel anti-inflammatory effects of taxifolin on microglia in an HG environment, which could help develop novel strategies for suppressing neuroinflammation in diabetes.
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Affiliation(s)
- Masayo Iwasa
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
| | - Hisashi Kato
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
| | - Kaori Iwashita
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
| | - Hajime Yamakage
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
| | - Sayaka Kato
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
- Department of Endocrinology and Metabolism, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Satoshi Saito
- Department of Neurology, National Cerebral and Cardiovascular Center, Osaka 564-8565, Japan
| | - Masafumi Ihara
- Department of Neurology, National Cerebral and Cardiovascular Center, Osaka 564-8565, Japan
| | - Hideo Nishimura
- Translational Research Center for Medical Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe 650-0047, Japan
| | - Atsuhiko Kawamoto
- Translational Research Center for Medical Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe 650-0047, Japan
| | - Takayoshi Suganami
- Department of Molecular Medicine and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
- Department of Immunometabolism, Nagoya University Graduate School of Medicine, Nagoya 464-8601, Japan
- Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya 464-8601, Japan
- Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Gifu 501-1193, Japan
| | - Masashi Tanaka
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
- Department of Rehabilitation, Health Science University, Minamitsuru-gun 401-0380, Japan
| | - Noriko Satoh-Asahara
- Department of Endocrinology, Metabolism and Hypertension Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto 612-8555, Japan
- Department of Metabolic Syndrome and Nutritional Science, Research Institute of Environmental Medicine, Nagoya University, Nagoya 466-8550, Japan
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