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Balan I, Boero G, Chéry SL, McFarland MH, Lopez AG, Morrow AL. Neuroactive Steroids, Toll-like Receptors, and Neuroimmune Regulation: Insights into Their Impact on Neuropsychiatric Disorders. Life (Basel) 2024; 14:582. [PMID: 38792602 PMCID: PMC11122352 DOI: 10.3390/life14050582] [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: 03/11/2024] [Revised: 04/18/2024] [Accepted: 04/28/2024] [Indexed: 05/26/2024] Open
Abstract
Pregnane neuroactive steroids, notably allopregnanolone and pregnenolone, exhibit efficacy in mitigating inflammatory signals triggered by toll-like receptor (TLR) activation, thus attenuating the production of inflammatory factors. Clinical studies highlight their therapeutic potential, particularly in conditions like postpartum depression (PPD), where the FDA-approved compound brexanolone, an intravenous formulation of allopregnanolone, effectively suppresses TLR-mediated inflammatory pathways, predicting symptom improvement. Additionally, pregnane neurosteroids exhibit trophic and anti-inflammatory properties, stimulating the production of vital trophic proteins and anti-inflammatory factors. Androstane neuroactive steroids, including estrogens and androgens, along with dehydroepiandrosterone (DHEA), display diverse effects on TLR expression and activation. Notably, androstenediol (ADIOL), an androstane neurosteroid, emerges as a potent anti-inflammatory agent, promising for therapeutic interventions. The dysregulation of immune responses via TLR signaling alongside reduced levels of endogenous neurosteroids significantly contributes to symptom severity across various neuropsychiatric disorders. Neuroactive steroids, such as allopregnanolone, demonstrate efficacy in alleviating symptoms of various neuropsychiatric disorders and modulating neuroimmune responses, offering potential intervention avenues. This review emphasizes the significant therapeutic potential of neuroactive steroids in modulating TLR signaling pathways, particularly in addressing inflammatory processes associated with neuropsychiatric disorders. It advances our understanding of the complex interplay between neuroactive steroids and immune responses, paving the way for personalized treatment strategies tailored to individual needs and providing insights for future research aimed at unraveling the intricacies of neuropsychiatric disorders.
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Affiliation(s)
- Irina Balan
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Department of Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Giorgia Boero
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA;
| | - Samantha Lucenell Chéry
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Neuroscience Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Minna H. McFarland
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Neuroscience Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alejandro G. Lopez
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - A. Leslie Morrow
- Bowles Center for Alcohol Studies, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (I.B.); (S.L.C.); (M.H.M.); (A.G.L.)
- Department of Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pharmacology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Vaňková M, Velíková M, Vejražková D, Včelák J, Lukášová P, Rusina R, Vaňková H, Jarolímová E, Kancheva R, Bulant J, Horáčková L, Bendlová B, Hill M. The Role of Steroidomics in the Diagnosis of Alzheimer's Disease and Type 2 Diabetes Mellitus. Int J Mol Sci 2023; 24:ijms24108575. [PMID: 37239922 DOI: 10.3390/ijms24108575] [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: 03/14/2023] [Revised: 05/04/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Epidemiological studies suggest an association between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). This study aimed to investigate the pathophysiological markers of AD vs. T2DM for each sex separately and propose models that would distinguish control, AD, T2DM, and AD-T2DM comorbidity groups. AD and T2DM differed in levels of some circulating steroids (measured mostly by GC-MS) and in other observed characteristics, such as markers of obesity, glucose metabolism, and liver function tests. Regarding steroid metabolism, AD patients (both sexes) had significantly higher sex hormone binding globulin (SHBG), cortisol, and 17-hydroxy progesterone, and lower estradiol and 5α-androstane-3α,17β-diol, compared to T2DM patients. However, compared to healthy controls, changes in the steroid spectrum (especially increases in levels of steroids from the C21 group, including their 5α/β-reduced forms, androstenedione, etc.) were similar in patients with AD and patients with T2DM, though more expressed in diabetics. It can be assumed that many of these steroids are involved in counter-regulatory protective mechanisms that mitigate the development and progression of AD and T2DM. In conclusion, our results demonstrated the ability to effectively differentiate AD, T2DM, and controls in both men and women, distinguish the two pathologies from each other, and differentiate patients with AD and T2DM comorbidities.
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Affiliation(s)
- Markéta Vaňková
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Marta Velíková
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | | | - Josef Včelák
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Petra Lukášová
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Robert Rusina
- Department of Neurology, Third Faculty of Medicine, Charles University and Thomayer University Hospital, Ruská 2411, 100 00 Prague, Czech Republic
| | - Hana Vaňková
- Third Faculty of Medicine, Charles University, Ruská 2411, 100 00 Prague, Czech Republic
| | - Eva Jarolímová
- Third Faculty of Medicine, Charles University, Ruská 2411, 100 00 Prague, Czech Republic
| | - Radmila Kancheva
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Josef Bulant
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Lenka Horáčková
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Běla Bendlová
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
| | - Martin Hill
- Institute of Endocrinology, Národní 8, 110 00 Prague, Czech Republic
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Abbas NA, Hassan HA. The protective and therapeutic effects of 5-androstene3β, 17β-diol (ADIOL) in abdominal post-operative adhesions in rat: Suppressing TLR4/NFκB/HMGB1/TGF1 β/α SMA pathway. Int Immunopharmacol 2022; 109:108801. [DOI: 10.1016/j.intimp.2022.108801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/17/2022] [Accepted: 04/22/2022] [Indexed: 11/29/2022]
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So SY, Savidge TC. Gut feelings: the microbiota-gut-brain axis on steroids. Am J Physiol Gastrointest Liver Physiol 2022; 322:G1-G20. [PMID: 34730020 PMCID: PMC8698538 DOI: 10.1152/ajpgi.00294.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 01/31/2023]
Abstract
The intricate connection between central and enteric nervous systems is well established with emerging evidence linking gut microbiota function as a significant new contributor to gut-brain axis signaling. Several microbial signals contribute to altered gut-brain communications, with steroids representing an important biological class that impacts central and enteric nervous system function. Neuroactive steroids contribute pathologically to neurological disorders, including dementia and depression, by modulating the activity of neuroreceptors. However, limited information is available on the influence of neuroactive steroids on the enteric nervous system and gastrointestinal function. In this review, we outline how steroids can modulate enteric nervous system function by focusing on their influence on different receptors that are present in the intestine in health and disease. We also highlight the potential role of the gut microbiota in modulating neuroactive steroid signaling along the gut-brain axis.
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Affiliation(s)
- Sik Yu So
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas
| | - Tor C Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas
- Department of Pathology, Texas Children's Microbiome Center, Texas Children's Hospital, Houston, Texas
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5
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Guo H, Baker G, Hartle K, Fujiwara E, Wang J, Zhang Y, Xing J, Lyu H, Li XM, Chen J. Exploratory study on neurochemical effects of low-intensity pulsed ultrasound in brains of mice. Med Biol Eng Comput 2021; 59:1099-1110. [PMID: 33881705 DOI: 10.1007/s11517-021-02351-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 03/19/2021] [Indexed: 01/25/2023]
Abstract
There is now a relatively large body of evidence suggesting a relationship between dysfunction of myelin and oligodendrocytes and the etiology of several neuropsychiatric disorders, including depression and schizophrenia, and also suggesting that ultrasound methods may alleviate some of the symptoms of depression. We have applied low-intensity pulsed ultrasound (LIPUS) to the brains of mice treated with the demyelinating drug cuprizone, a drug that has been used as the basis for a rodent model relevant to a number of psychiatric and neurologic disorders including depression, schizophrenia, and multiple sclerosis. Prior to conducting the studies in mice, preliminary studies were carried out on the effects of LIPUS in vitro in neuron-like SH-SY5Y cells and primary glial cells. In subsequent studies in mice, female C57BL/6 mice were restrained in plastic tubes for 20 min daily with the ultrasound transducer near the end of the tube directly above the mouse's head. LIPUS was used at an intensity of 25 mW/cm2 once daily for 22 days in control mice and in mice undergoing daily repetitive restraint stress (RRS). Behavioral or neurochemical studies were done on the mice or the brain tissue obtained from them. The studies in vitro indicated that LIPUS stimulation at an intensity of 15 mW/cm2 delivered for 5 min daily for 3 days in an enclosed sterile cell culture plate in an incubator increased the viability of SH-SY5Y and primary glial cells. In the studies in mice, LIPUS elevated levels of doublecortin, a marker for neurogenesis, in the cortex compared to levels in the RRS mice and caused a trend in elevation of brain levels of brain-derived neurotrophic factor in the hippocampus relative to control levels. LIPUS also increased sucrose preference (a measure of the attenuation of anhedonia, a common symptom of several psychiatric disorders) in the RRS model in mice. The ability of LIPUS administered daily to rescue damaged myelin and oligodendrocytes was studied in mice treated chronically with cuprizone for 35 days. LIPUS increased cortex and corpus callosum levels of myelin basic protein, a protein marker for mature oligodendrocytes, and neural/glial antigen 2, a protein marker for oligodendrocyte precursor cells, relative to levels in the cuprizone + sham animals. These results of this exploratory study suggest that future comprehensive time-related studies with LIPUS on brain chemistry and behavior related to neuropsychiatric disorders are warranted. Exploratory Study on Neurochemical Effects of Low Intensity Pulsed Ultrasound in Brains of Mice. Upper part of figure: LIPUS device and in-vitro cell experimental set-up. The center image is the LIPUS generating box; the image in the upper left shows the cell experiment set-up; the image in the upper right shows a zoomed-in sketch for the cell experiment; the image in the lower left shows the set-up of repetitive restraint stress (RRS) with a mouse; the image in the lower middle shows the set-up of LIPUS treatment of a mouse; the image in the lower right shows a zoomed-in sketch for the LIPUS treatment of a mouse.
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Affiliation(s)
- Huining Guo
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada
| | - Glen Baker
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada.,Neuroscience & Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Kelly Hartle
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada.,Neuroscience & Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Esther Fujiwara
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada.,Neuroscience & Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Junhui Wang
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada
| | - Yanbo Zhang
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada.,Neuroscience & Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Jida Xing
- Department of Electrical and Computer Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada
| | - Haiyan Lyu
- Department of Pharmacy, Xianyue Hospital, Xiamen, China
| | - Xin-Min Li
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, TGG 2B7, Canada. .,Neuroscience & Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
| | - Jie Chen
- Department of Electrical and Computer Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada. .,Department of Biomedical Engineering, Faculty of Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
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Shaw JC, Crombie GK, Palliser HK, Hirst JJ. Impaired Oligodendrocyte Development Following Preterm Birth: Promoting GABAergic Action to Improve Outcomes. Front Pediatr 2021; 9:618052. [PMID: 33634057 PMCID: PMC7901941 DOI: 10.3389/fped.2021.618052] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/12/2021] [Indexed: 11/21/2022] Open
Abstract
Preterm birth is associated with poor long-term neurodevelopmental and behavioral outcomes, even in the absence of obvious brain injury at the time of birth. In particular, behavioral disorders characterized by inattention, social difficulties and anxiety are common among children and adolescents who were born moderately to late preterm (32-37 weeks' gestation). Diffuse deficits in white matter microstructure are thought to play a role in these poor outcomes with evidence suggesting that a failure of oligodendrocytes to mature and myelinate axons is responsible. However, there remains a major knowledge gap over the mechanisms by which preterm birth interrupts normal oligodendrocyte development. In utero neurodevelopment occurs in an inhibitory-dominant environment due to the action of placentally derived neurosteroids on the GABAA receptor, thus promoting GABAergic inhibitory activity and maintaining the fetal behavioral state. Following preterm birth, and the subsequent premature exposure to the ex utero environment, this action of neurosteroids on GABAA receptors is greatly reduced. Coinciding with a reduction in GABAergic inhibition, the preterm neonatal brain is also exposed to ex utero environmental insults such as periods of hypoxia and excessive glucocorticoid concentrations. Together, these insults may increase levels of the excitatory neurotransmitter glutamate in the developing brain and result in a shift in the balance of inhibitory: excitatory activity toward excitatory. This review will outline the normal development of oligodendrocytes, how it is disrupted under excitation-dominated conditions and highlight how shifting the balance back toward an inhibitory-dominated environment may improve outcomes.
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Affiliation(s)
- Julia C Shaw
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia.,Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Gabrielle K Crombie
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia.,Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Hannah K Palliser
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia.,Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Jonathan J Hirst
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia.,Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
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7
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Gilchrist SE, Goudarzi S, Hafizi S. Gas6 Inhibits Toll-Like Receptor-Mediated Inflammatory Pathways in Mouse Microglia via Axl and Mer. Front Cell Neurosci 2020; 14:576650. [PMID: 33192322 PMCID: PMC7584110 DOI: 10.3389/fncel.2020.576650] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/08/2020] [Indexed: 12/30/2022] Open
Abstract
Background: Microglia are well known key regulators of neuroinflammation which feature in multiple neurodegenerative disorders. These cells survey the CNS and, under inflammatory conditions, become "activated" through stimulation of toll-like receptors (TLRs), resulting in changes in morphology and production and release of cytokines. In the present study, we examined the roles of the related TAM receptors, Mer and Axl, and of their ligand, Gas6, in the regulation of microglial pro-inflammatory TNF-α production and microglial morphology. Methods: Primary cultures of murine microglia of wild-type (WT), Mer-/- and Axl-/- backgrounds were stimulated by the TLR4 agonist, lipopolysaccharide (LPS) with or without pre-treatment with Gas6. Gene expression of TNF-α, Mer, and Axl was examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) was used to measure TNF-α release from microglia. Immunofluorescence staining of β-actin and the microglial marker Iba1 was performed to reveal microglial morphological changes, with cellular characteristics (area, perimeter, Feret's diameter, minimum Feret, roundness, and aspect ratio) being quantified using ImageJ software. Results: Under basal conditions, TNF-α gene expression was significantly lower in Axl-/- microglia compared to WT cells. However, all microglial cultures robustly responded to LPS stimulation with the upregulation of TNF-α expression to similar degrees. Furthermore, Mer receptor expression was less responsive to LPS stimulation when in Axl knockout cells. The presence of Gas6 consistently inhibited the LPS-induced upregulation of TNF-α in WT, Mer-/- and Axl-/- microglia. Moreover, Gas6 also inhibited LPS-induced changes in the microglial area, perimeter length, and cell roundness in wild-type cells. Conclusion: Gas6 can negatively regulate the microglial pro-inflammatory response to LPS as well as via stimulation of other TLRs, acting through either of the TAM receptors, Axl and Mer. This finding indicates an interaction between TLR and TAM receptor signaling pathways and reveals an anti-inflammatory role for the TAM ligand, Gas6, which could have therapeutic potential.
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Affiliation(s)
- Shannon E Gilchrist
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Salman Goudarzi
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Sassan Hafizi
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
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8
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Detrimental and protective action of microglial extracellular vesicles on myelin lesions: astrocyte involvement in remyelination failure. Acta Neuropathol 2019; 138:987-1012. [PMID: 31363836 PMCID: PMC6851224 DOI: 10.1007/s00401-019-02049-1] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/17/2022]
Abstract
Microglia are highly plastic immune cells which exist in a continuum of activation states. By shaping the function of oligodendrocyte precursor cells (OPCs), the brain cells which differentiate to myelin-forming cells, microglia participate in both myelin injury and remyelination during multiple sclerosis. However, the mode(s) of action of microglia in supporting or inhibiting myelin repair is still largely unclear. Here, we analysed the effects of extracellular vesicles (EVs) produced in vitro by either pro-inflammatory or pro-regenerative microglia on OPCs at demyelinated lesions caused by lysolecithin injection in the mouse corpus callosum. Immunolabelling for myelin proteins and electron microscopy showed that EVs released by pro-inflammatory microglia blocked remyelination, whereas EVs produced by microglia co-cultured with immunosuppressive mesenchymal stem cells promoted OPC recruitment and myelin repair. The molecular mechanisms responsible for the harmful and beneficial EV actions were dissected in primary OPC cultures. By exposing OPCs, cultured either alone or with astrocytes, to inflammatory EVs, we observed a blockade of OPC maturation only in the presence of astrocytes, implicating these cells in remyelination failure. Biochemical fractionation revealed that astrocytes may be converted into harmful cells by the inflammatory EV cargo, as indicated by immunohistochemical and qPCR analyses, whereas surface lipid components of EVs promote OPC migration and/or differentiation, linking EV lipids to myelin repair. Although the mechanisms through which the lipid species enhance OPC maturation still remain to be fully defined, we provide the first demonstration that vesicular sphingosine 1 phosphate stimulates OPC migration, the first fundamental step in myelin repair. From this study, microglial EVs emerge as multimodal and multitarget signalling mediators able to influence both OPCs and astrocytes around myelin lesions, which may be exploited to develop novel approaches for myelin repair not only in multiple sclerosis, but also in neurological and neuropsychiatric diseases characterized by demyelination.
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Mouihate A, Kalakh S. Ganaxolone enhances microglial clearance activity and promotes remyelination in focal demyelination in the corpus callosum of ovariectomized rats. CNS Neurosci Ther 2019; 26:240-250. [PMID: 31332963 PMCID: PMC6978248 DOI: 10.1111/cns.13195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 06/24/2019] [Accepted: 06/27/2019] [Indexed: 12/01/2022] Open
Abstract
Aim Experimental studies have shown that the progesterone metabolite, allopregnanolone, is endowed with promyelinating effects. The mechanisms underlying these promyelinating effects are not well understood. Therefore, we explored the impact of allopregnanolone's synthetic analogue, ganaxolone, on remyelination and microglial activation following focal demyelination in the corpus callosum of ovariectomized rats. Methods Ovariectomized adult Sprague Dawley rats received a stereotaxic injection of 2 µL of 1% lysolecithin solution in the corpus callosum followed by daily injections of either ganaxolone (intraperitoneal injection [i.p.], 2.5 mg/kg) or vehicle. The demyelination lesion was assessed 3 and 7 days postdemyelination insult using Luxol fast blue staining and transmission electron microscopy. The expression levels of myelin proteins (MBP, MAG, MOG, CNPase) were explored using Western blot. The inflammatory response and clearance of damaged myelin were evaluated using immunofluorescent staining (Iba1, dMBP, GFAP) and multiplex enzyme‐linked immunosorbent assay (IL‐1β, TNF‐α, IL‐4, IL‐10, IL‐6). Results Systemic administration of ganaxolone promoted remyelination of lysolecithin‐induced demyelination, upregulated the expression of major myelin proteins, and enhanced microglial clearance of damaged myelin. Astrocytosis, as well as locally produced pro‐ and antiinflammatory cytokines, was not affected by ganaxolone treatment. Conclusion Ganaxolone promotes remyelination in response to focal demyelination of the corpus callosum of ovariectomized rats. This effect is, at least in part, mediated by enhancing microglial clearance of myelin debris, which creates a conducive environment for a successful remyelination process.
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Affiliation(s)
- Abdeslam Mouihate
- Department of Physiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Samah Kalakh
- Department of Physiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
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10
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Enhanced remyelination during late pregnancy: involvement of the GABAergic system. Sci Rep 2019; 9:7728. [PMID: 31118452 PMCID: PMC6531481 DOI: 10.1038/s41598-019-44050-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 05/08/2019] [Indexed: 11/08/2022] Open
Abstract
Pregnant women with MS experience fewer relapses, especially during the third trimester. In this study, we explore the cellular and molecular events that bring about the protective effect of late pregnancy on the course of de/remyelination in rats. Using cellular, molecular, and ultrastructural methods, we explored remyelination in response to a focal demyelination in the corpus callosum of late pregnant, virgin, and postpartum rats. We further explored the role of GABAA receptor (GABAAR) in the promyelinating effect observed during late pregnancy. Remyelination in response to a gliotoxin-induced demyelination in the corpus callosum was enhanced in late pregnant rats when compared to that seen in virgin and postpartum rats. This pregnancy-associated promyelinating effect was lost when either the GABAAR was blocked or when 5α-reductase, the rate limiting enzyme for the endogenous GABAAR activator allopregnanolone, was inhibited. Taken together, these data suggest that the pregnancy-associated pro-myelination operates, at least in part, through a GABAergic activated system.
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11
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Transferrin Enhances Microglial Phagocytic Capacity. Mol Neurobiol 2019; 56:6324-6340. [PMID: 30758712 DOI: 10.1007/s12035-019-1519-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/29/2019] [Indexed: 01/01/2023]
Abstract
Transferrin (Tf) is a glycoprotein playing a critical role in iron homeostasis and transport and distribution throughout the body and within tissues and cells. This molecule has been shown to accelerate the process of myelination and remyelination in the central nervous system (CNS) in vivo and induce oligodendroglial cell maturation in vitro. While the mechanisms involved in oligodendroglial precursor cell (OPC) differentiation have not been fully elucidated yet, our group has previously described the first molecular events taking place in OPC in response to extracellular Tf. Here, we show the effect of Tf on the different glial cell populations. We demonstrate that, after a CNS demyelinating injury, Tf can be incorporated by all glial cells-i.e., microglia, astrocytes, and OPC-and that, acting on microglial cells in vitro, Tf increases microglial proliferation rates and phagocytic capacity. It may be then speculated that the in vivo correlation of this process could generate a favorable microenvironment for OPC maturation and remyelination.
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12
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Mouihate A, Al-Hashash H, Rakhshani-Moghadam S, Kalakh S. Impact of prenatal immune challenge on the demyelination injury during adulthood. CNS Neurosci Ther 2017; 23:724-735. [PMID: 28718218 DOI: 10.1111/cns.12718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/20/2017] [Accepted: 06/23/2017] [Indexed: 12/24/2022] Open
Abstract
AIM Brain inflammation is associated with several brain diseases such as multiple sclerosis (MS), a disease characterized by demyelination. Whether prenatal immune challenge affects demyelination-induced inflammation in the white matter during adulthood is unclear. In the present study, we used a well-established experimental model of focal demyelination to assess whether prenatal immune challenge affects demyelination-induced inflammation. METHODS Pregnant rats were injected with either lipopolysaccharide (100 μg/kg, ip) or pyrogen-free saline. A 2 μL solution of the gliotoxin ethidium bromide (0.04%) was stereotaxically infused into the corpus callosum of adult male offspring. The extent of demyelination lesion was assessed using Luxol fast blue (LFB) staining. Oligodendrocyte precursor cells, mature oligodendrocytes, markers of cellular gliosis, and inflammation were monitored in the vicinity of the demyelination lesion area. RESULTS Prenatal lipopolysaccharide reduced the size of the demyelination lesion during adulthood. This reduced lesion was associated with enhanced density of mature oligodendrocytes and reduced density of microglial cells in the vicinity of the demyelination lesion. Such reduction in microglial cell density was accompanied by a reduced activation of the nuclear factor κB signaling pathway. CONCLUSION These data strongly suggest that prenatal immune challenge dampens the extent of demyelination during adulthood likely by reprogramming the local brain inflammatory response to demyelinating insults.
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Affiliation(s)
- Abdeslam Mouihate
- Faculty of Medicine, Department of Physiology, Kuwait University, Safat, Kuwait
| | - Hessah Al-Hashash
- Faculty of Medicine, Department of Physiology, Kuwait University, Safat, Kuwait
| | | | - Samah Kalakh
- Faculty of Medicine, Department of Physiology, Kuwait University, Safat, Kuwait
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