1
|
Eugenín J, Beltrán-Castillo S, Irribarra E, Pulgar-Sepúlveda R, Abarca N, von Bernhardi R. Microglial reactivity in brainstem chemosensory nuclei in response to hypercapnia. Front Physiol 2024; 15:1332355. [PMID: 38476146 PMCID: PMC10927973 DOI: 10.3389/fphys.2024.1332355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 02/08/2024] [Indexed: 03/14/2024] Open
Abstract
Microglia, the resident immune cells of the CNS, surveil, detect, and respond to various extracellular signals. Depending on the nature of these signals, an integrative microglial response can be triggered, resulting in a phenotypic transformation. Here, we evaluate whether hypercapnia modifies microglia phenotype in brainstem respiratory-related nuclei. Adult C57BL/6 inbred mice were exposed to 10% CO2 enriched air (hypercapnia), or pure air (control), for 10 or 30 min and immediately processed for immunohistochemistry to detect the ubiquitous microglia marker, ionized calcium binding adaptor molecule 1 (Iba1). Hypercapnia for thirty, but not 10 min reduced the Iba1 labeling percent coverage in the ventral respiratory column (VRC), raphe nucleus (RN), and nucleus tractus solitarius (NTS) and the number of primary branches in VRC. The morphological changes persisted, at least, for 60 min breathing air after the hypercapnic challenge. No significant changes were observed in Iba1+ cells in the spinal trigeminal nucleus (Sp5) and the hippocampus. In CF-1 outbred mice, 10% CO2 followed by 60 min of breathing air, resulted in the reduction of Iba1 labeling percent coverage and the number and length of primary branches in VRC, RN, and NTS. No morphological change was observed in Iba1+ cells in Sp5 and hippocampus. Double immunofluorescence revealed that prolonged hypercapnia increased the expression of CD86, an inflammatory marker for reactive state microglia, in Iba1+ cells in VRC, RN, and NTS, but not in Sp5 and hippocampus in CF-1 mice. By contrast, the expression of CD206, a marker of regulatory state microglia, persisted unmodified. In brainstem, but not in hippocampal microglia cultures, hypercapnia increased the level of IL1β, but not that of TGFβ measured by ELISA. Our results show that microglia from respiratory-related chemosensory nuclei, are reactive to prolonged hypercapnia acquiring an inflammatory-like phenotype.
Collapse
Affiliation(s)
- Jaime Eugenín
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Sebastián Beltrán-Castillo
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
- Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
| | - Estefanía Irribarra
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | | | - Nicolás Abarca
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Rommy von Bernhardi
- Facultad de Odontología y Ciencias de la Rehabilitación, Universidad San Sebastián, Santiago, Chile
| |
Collapse
|
2
|
Eugenín J, Eugenín-von Bernhardi L, von Bernhardi R. Age-dependent changes on fractalkine forms and their contribution to neurodegenerative diseases. Front Mol Neurosci 2023; 16:1249320. [PMID: 37818457 PMCID: PMC10561274 DOI: 10.3389/fnmol.2023.1249320] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/06/2023] [Indexed: 10/12/2023] Open
Abstract
The chemokine fractalkine (FKN, CX3CL1), a member of the CX3C subfamily, contributes to neuron-glia interaction and the regulation of microglial cell activation. Fractalkine is expressed by neurons as a membrane-bound protein (mCX3CL1) that can be cleaved by extracellular proteases generating several sCX3CL1 forms. sCX3CL1, containing the chemokine domain, and mCX3CL1 have high affinity by their unique receptor (CX3CR1) which, physiologically, is only found in microglia, a resident immune cell of the CNS. The activation of CX3CR1contributes to survival and maturation of the neural network during development, glutamatergic synaptic transmission, synaptic plasticity, cognition, neuropathic pain, and inflammatory regulation in the adult brain. Indeed, the various CX3CL1 forms appear in some cases to serve an anti-inflammatory role of microglia, whereas in others, they have a pro-inflammatory role, aggravating neurological disorders. In the last decade, evidence points to the fact that sCX3CL1 and mCX3CL1 exhibit selective and differential effects on their targets. Thus, the balance in their level and activity will impact on neuron-microglia interaction. This review is focused on the description of factors determining the emergence of distinct fractalkine forms, their age-dependent changes, and how they contribute to neuroinflammation and neurodegenerative diseases. Changes in the balance among various fractalkine forms may be one of the mechanisms on which converge aging, chronic CNS inflammation, and neurodegeneration.
Collapse
Affiliation(s)
- Jaime Eugenín
- Facultad de Química y Biología, Departamento de Biología, Universidad de Santiago de Chile, USACH, Santiago, Chile
| | | | - Rommy von Bernhardi
- Facultad de Ciencias para el Cuidado de la Salud, Universidad San Sebastián, Santiago, Chile
| |
Collapse
|
3
|
Anwar MJ, Alenezi SK, Alhowail AH. Molecular insights into the pathogenic impact of vitamin D deficiency in neurological disorders. Biomed Pharmacother 2023; 162:114718. [PMID: 37084561 DOI: 10.1016/j.biopha.2023.114718] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/23/2023] Open
Abstract
Neurological disorders are the major cause of disability, leading to a decrease in quality of life by impairing cognitive, sensorimotor, and motor functioning. Several factors have been proposed in the pathogenesis of neurobehavioral changes, including nutritional, environmental, and genetic predisposition. Vitamin D (VD) is an environmental and nutritional factor that is widely distributed in the central nervous system's subcortical grey matter, neurons of the substantia nigra, hippocampus, thalamus, and hypothalamus. It is implicated in the regulation of several brain functions by preserving neuronal structures. It is a hormone rather than a nutritional vitamin that exerts a regulatory role in the pathophysiology of several neurological disorders, including Alzheimer's disease, Parkinson's disease, epilepsy, and multiple sclerosis. A growing body of epidemiological evidence suggests that VD is critical in neuronal development and shows neuroprotective effects by influencing the production and release of neurotrophins, antioxidants, immunomodulatory, regulation of intracellular calcium balance, and direct effect on the growth and differentiation of nerve cells. This review provides up-to-date and comprehensive information on vitamin D deficiency, risk factors, and clinical and preclinical evidence on its relationship with neurological disorders. Furthermore, this review provides mechanistic insight into the implications of vitamin D and its deficiency on the pathogenesis of neurological disorders. Thus, an understanding of the crucial role of vitamin D in the neurobiology of neurodegenerative disorders can assist in the better management of vitamin D-deficient individuals.
Collapse
Affiliation(s)
- Md Jamir Anwar
- Department of Pharmacology and Toxicology, Unaizah College of Pharmacy, Qassim University, Qassim, Unaizah 51911, Saudi Arabia
| | - Sattam Khulaif Alenezi
- Department of Pharmacology and Toxicology, Unaizah College of Pharmacy, Qassim University, Qassim, Unaizah 51911, Saudi Arabia.
| | - Ahmad Hamad Alhowail
- Department of Pharmacology and Toxicology, College of Pharmacy, Qassim University, Qassim, Buraydah 51452, Saudi Arabia
| |
Collapse
|
4
|
Lyros E, Ragoschke-Schumm A, Kostopoulos P, Sehr A, Backens M, Kalampokini S, Decker Y, Lesmeister M, Liu Y, Reith W, Fassbender K. Normal brain aging and Alzheimer's disease are associated with lower cerebral pH: an in vivo histidine 1H-MR spectroscopy study. Neurobiol Aging 2019; 87:60-69. [PMID: 31902521 DOI: 10.1016/j.neurobiolaging.2019.11.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 11/09/2019] [Accepted: 11/17/2019] [Indexed: 01/21/2023]
Abstract
It is unclear whether alterations in cerebral pH underlie Alzheimer's disease (AD) and other dementias. We performed proton spectroscopy after oral administration of histidine in healthy young and elderly persons and in patients with mild cognitive impairment and dementia (total N = 147). We measured cerebral tissue pH and ratios of common brain metabolites in relation to phosphocreatine and creatine (Cr) in spectra acquired from the hippocampus, the white matter (WM) of the centrum semiovale, and the cerebellum. Hippocampal pH was inversely associated with age in healthy participants but did not differ between patients and controls. WM pH was low in AD and, to a lesser extent, mild cognitive impairment but not in frontotemporal dementia spectrum disorders and pure vascular dementia. Furthermore, WM pH provided incremental diagnostic value in addition to N-acetylaspartate to Cr ratio. Our study suggests that in vivo assessment of pH may be a useful marker for the differentiation between AD and other types of dementia.
Collapse
Affiliation(s)
| | | | - Panagiotis Kostopoulos
- Department of Neurology, Saarland University Clinic, Homburg, Germany; Medical Park Bad Camberg, Germany
| | - Alexandra Sehr
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Martin Backens
- Department of Neuroradiology, Saarland University Clinic, Homburg, Germany
| | | | - Yann Decker
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Martin Lesmeister
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Yang Liu
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Wolfgang Reith
- Department of Neuroradiology, Saarland University Clinic, Homburg, Germany
| | - Klaus Fassbender
- Department of Neurology, Saarland University Clinic, Homburg, Germany.
| |
Collapse
|
5
|
Baldini N, Avnet S. The Effects of Systemic and Local Acidosis on Insulin Resistance and Signaling. Int J Mol Sci 2018; 20:ijms20010126. [PMID: 30598026 PMCID: PMC6337415 DOI: 10.3390/ijms20010126] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 12/12/2018] [Accepted: 12/23/2018] [Indexed: 12/14/2022] Open
Abstract
Most pathological conditions that cause local or systemic acidosis by overcoming the buffering activities of body fluids overlap with those diseases that are characterized by glucose metabolic disorders, including diabetes mellitus, inflammation, and cancer. This simple observation suggests the existence of a strong relationship between acidosis and insulin metabolism or insulin receptor signaling. In this review, we summarized the current knowledge on the activity of insulin on the induction of acidosis and, vice versa, on the effects of changes of extracellular and intracellular pH on insulin resistance. Insulin influences acidosis by promoting glycolysis. Although with an unclear mechanism, the lowering of pH, in turn, inhibits insulin sensitivity or activity. In addition to ketoacidosis that is frequently associated with diabetes, other important and more complex factors are involved in this delicate feedback mechanism. Among these, in this review we discussed the acid-mediated inhibiting effects on insulin binding affinity to its receptor, on glycolysis, on the recycling of glucose transporters, and on insulin secretion via transforming growth factor β (TGF-β) activity by pancreatic β-cells. Finally, we revised current data available on the mutual interaction between insulin signaling and the activity of ion/proton transporters and pH sensors, and on how acidosis may enhance insulin resistance through the Nuclear Factor kappa B (NF-κB) inflammatory pathway.
Collapse
Affiliation(s)
- Nicola Baldini
- Orthopaedic Pathophysiology and Regenerative Medicine Unit, Istituto Ortopedico Rizzoli IRCCS, 40136 Bologna, Italy.
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 401223 Bologna, Italy.
| | - Sofia Avnet
- Orthopaedic Pathophysiology and Regenerative Medicine Unit, Istituto Ortopedico Rizzoli IRCCS, 40136 Bologna, Italy.
| |
Collapse
|
6
|
Eugenín J, Vecchiola A, Murgas P, Arroyo P, Cornejo F, von Bernhardi R. Expression Pattern of Scavenger Receptors and Amyloid-β Phagocytosis of Astrocytes and Microglia in Culture are Modified by Acidosis: Implications for Alzheimer’s Disease. J Alzheimers Dis 2016; 53:857-73. [DOI: 10.3233/jad-160083] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jaime Eugenín
- Laboratory of Neural Systems, Department of Biology, Faculty of Chemistry and Biology, Universidad de Santiago de Chile (USACH), Santiago, Chile
| | - Andrea Vecchiola
- Laboratory of Neuroscience, Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Endocrinology, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Paola Murgas
- Laboratory of Neuroscience, Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Arroyo
- Laboratory of Neuroscience, Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisca Cornejo
- Laboratory of Neuroscience, Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rommy von Bernhardi
- Laboratory of Neuroscience, Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| |
Collapse
|
7
|
Radu BM, Banciu A, Banciu DD, Radu M. Acid-Sensing Ion Channels as Potential Pharmacological Targets in Peripheral and Central Nervous System Diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:137-67. [PMID: 26920689 DOI: 10.1016/bs.apcsb.2015.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Acid-sensing ion channels (ASICs) are widely expressed in the body and represent good sensors for detecting protons. The pH drop in the nervous system is equivalent to ischemia and acidosis, and ASICs are very good detectors in discriminating slight changes in acidity. ASICs are important pharmacological targets being involved in a variety of pathophysiological processes affecting both the peripheral nervous system (e.g., peripheral pain, diabetic neuropathy) and the central nervous system (e.g., stroke, epilepsy, migraine, anxiety, fear, depression, neurodegenerative diseases, etc.). This review discusses the role played by ASICs in different pathologies and the pharmacological agents acting on ASICs that might represent promising drugs. As the majority of above-mentioned pathologies involve not only neuronal dysfunctions but also microvascular alterations, in the next future, ASICs may be also considered as potential pharmacological targets at the vasculature level. Perspectives and limitations in the use of ASICs antagonists and modulators as pharmaceutical agents are also discussed.
Collapse
Affiliation(s)
- Beatrice Mihaela Radu
- Department of Neurological and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy; Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Adela Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Daniel Dumitru Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Mihai Radu
- Department of Neurological and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy; Department of Life and Environmental Physics, 'Horia Hulubei' National Institute for Physics and Nuclear Engineering, Magurele, Romania.
| |
Collapse
|
8
|
von Bernhardi R, Cornejo F, Parada GE, Eugenín J. Role of TGFβ signaling in the pathogenesis of Alzheimer's disease. Front Cell Neurosci 2015; 9:426. [PMID: 26578886 PMCID: PMC4623426 DOI: 10.3389/fncel.2015.00426] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 10/09/2015] [Indexed: 12/19/2022] Open
Abstract
Aging is the main risk factor for Alzheimer’s disease (AD); being associated with conspicuous changes on microglia activation. Aged microglia exhibit an increased expression of cytokines, exacerbated reactivity to various stimuli, oxidative stress, and reduced phagocytosis of β-amyloid (Aβ). Whereas normal inflammation is protective, it becomes dysregulated in the presence of a persistent stimulus, or in the context of an inflammatory environment, as observed in aging. Thus, neuroinflammation can be a self-perpetuating deleterious response, becoming a source of additional injury to host cells in neurodegenerative diseases. In aged individuals, although transforming growth factor β (TGFβ) is upregulated, its canonical Smad3 signaling is greatly reduced and neuroinflammation persists. This age-related Smad3 impairment reduces protective activation while facilitating cytotoxic activation of microglia through several cellular mechanisms, potentiating microglia-mediated neurodegeneration. Here, we critically discuss the role of TGFβ-Smad signaling on the cytotoxic activation of microglia and its relevance in the pathogenesis of AD. Other protective functions, such as phagocytosis, although observed in aged animals, are not further induced by inflammatory stimuli and TGFβ1. Analysis in silico revealed that increased expression of receptor scavenger receptor (SR)-A, involved in Aβ uptake and cell activation, by microglia exposed to TGFβ, through a Smad3-dependent mechanism could be mediated by transcriptional co-factors Smad2/3 over the MSR1 gene. We discuss that changes of TGFβ-mediated regulation could at least partially mediate age-associated microglia changes, and, together with other changes on inflammatory response, could result in the reduction of protective activation and the potentiation of cytotoxicity of microglia, resulting in the promotion of neurodegenerative diseases.
Collapse
Affiliation(s)
- Rommy von Bernhardi
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Francisca Cornejo
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Guillermo E Parada
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Jaime Eugenín
- Laboratory of Neural Systems, Faculty of Chemistry and Biology, Department of Biology, Universidad de Santiago de Chile Santiago, Chile
| |
Collapse
|
9
|
Tichauer JE, Flores B, Soler B, Bernhardi LEV, Ramírez G, von Bernhardi R. Age-dependent changes on TGFβ1 Smad3 pathway modify the pattern of microglial cell activation. Brain Behav Immun 2014; 37:187-96. [PMID: 24380849 PMCID: PMC3951654 DOI: 10.1016/j.bbi.2013.12.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/22/2013] [Accepted: 12/23/2013] [Indexed: 12/22/2022] Open
Abstract
Aging is the main risk factor for Alzheimer's disease. Among other characteristics, it shows changes in inflammatory signaling that could affect the regulation of glial cell activation. We have shown that astrocytes prevent microglial cell cytotoxicity by mechanisms mediated by TGFβ1. However, whereas TGFβ1 is increased, glial cell activation persists in aging. To understand this apparent contradiction, we studied TGFβ1-Smad3 signaling during aging and their effect on microglial cell function. TGFβ1 induction and activation of Smad3 signaling in the hippocampus by inflammatory stimulation was greatly reduced in adult mice. We evaluated the effect of TGFβ1-Smad3 pathway on the regulation of nitric oxide (NO) and reactive oxygen species (ROS) secretion, and phagocytosis of microglia from mice at different ages with and without in vivo treatment with lipopolysaccharide (LPS) to induce an inflammatory status. NO secretion was only induced on microglia from young mice exposed to LPS, and was potentiated by inflammatory preconditioning, whereas in adult mice the induction of ROS was predominant. TGFβ1 modulated induction of NO and ROS production in young and adult microglia, respectively. Modulation was partially dependent on Smad3 pathway and was impaired by inflammatory preconditioning. Phagocytosis was induced by inflammation and TGFβ1 only in microglia cultures from young mice. Induction by TGFβ1 was also prevented by Smad3 inhibition. Our findings suggest that activation of the TGFβ1-Smad3 pathway is impaired in aging. Age-related impairment of TGFβ1-Smad3 can reduce protective activation while facilitating cytotoxic activation of microglia, potentiating microglia-mediated neurodegeneration.
Collapse
Affiliation(s)
| | | | | | | | | | - Rommy von Bernhardi
- Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
| |
Collapse
|
10
|
Orellana JA, Montero TD, von Bernhardi R. Astrocytes inhibit nitric oxide-dependent Ca(2+) dynamics in activated microglia: involvement of ATP released via pannexin 1 channels. Glia 2013; 61:2023-37. [PMID: 24123492 DOI: 10.1002/glia.22573] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 08/13/2013] [Accepted: 08/19/2013] [Indexed: 01/22/2023]
Abstract
Under inflammatory conditions, microglia exhibit increased levels of free intracellular Ca(2+) and produce high amounts of nitric oxide (NO). However, whether NO, Ca(2+) dynamics, and gliotransmitter release are reciprocally modulated is not fully understood. More importantly, the effect of astrocytes in the potentiation or suppression of such signaling is unknown. Our aim was to address if astrocytes could regulate NO-dependent Ca(2+) dynamics and ATP release in LPS-stimulated microglia. Griess assays and Fura-2AM time-lapse fluorescence images of microglia revealed that LPS produced an increased basal [Ca(2+) ]i that depended on the sequential activation of iNOS, COXs, and EP1 receptor. TGFβ1 released by astrocytes inhibited the abovementioned responses and also abolished LPS-induced ATP release by microglia. Luciferin/luciferase assays and dye uptake experiments showed that release of ATP from LPS-stimulated microglia occurred via pannexin 1 (Panx1) channels, but not connexin 43 hemichannels. Moreover, in LPS-stimulated microglia, exogenous ATP triggered activation of purinergic P2Y1 receptors resulting in Ca(2+) release from intracellular stores. Interestingly, TGFβ1 released by astrocytes inhibited ATP-induced Ca(2+) response in LPS-stimulated microglia to that observed in control microglia. Finally, COX/EP1 receptor signaling and activation of P2 receptors via ATP released through Panx1 channels were critical for the increased NO production in LPS-stimulated microglia. Thus, Ca(2+) dynamics depended on the inflammatory profile of microglia and could be modulated by astrocytes. The understanding of mechanisms underlying glial cell regulatory crosstalk could contribute to the development of new treatments to reduce inflammatory cytotoxicity in several brain pathologies.
Collapse
Affiliation(s)
- Juan A Orellana
- Departamento de Neurología; Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | | | |
Collapse
|
11
|
Quintanilla RA, Orellana JA, von Bernhardi R. Understanding Risk Factors for Alzheimer's Disease: Interplay of Neuroinflammation, Connexin-based Communication and Oxidative Stress. Arch Med Res 2012; 43:632-44. [DOI: 10.1016/j.arcmed.2012.10.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 10/22/2012] [Indexed: 12/11/2022]
|
12
|
Pál G, Vincze C, Renner É, Wappler EA, Nagy Z, Lovas G, Dobolyi A. Time course, distribution and cell types of induction of transforming growth factor betas following middle cerebral artery occlusion in the rat brain. PLoS One 2012; 7:e46731. [PMID: 23056426 PMCID: PMC3466286 DOI: 10.1371/journal.pone.0046731] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 09/03/2012] [Indexed: 01/04/2023] Open
Abstract
Transforming growth factor-βs (TGF-β1–3) are cytokines that regulate the proliferation, differentiation, and survival of various cell types. The present study describes the induction of TGF-β1–3 in the rat after focal ischemia at 3 h, 24 h, 72 h and 1 month after transient (1 h) or permanent (24 h) middle cerebral artery occlusion (MCAO) using in situ hybridization histochemistry and quantitative analysis. Double labeling with different markers was used to identify the localization of TGF-β mRNA relative to the penumbra and glial scar, and the types of cells expressing TGF-βs. TGF-β1 expression increased 3 h after MCAO in the penumbra and was further elevated 24 h after MCAO. TGF-β1 was present mostly in microglial cells but also in some astrocytes. By 72 h and 1 month after the occlusion, TGF-β1 mRNA-expressing cells also appeared in microglia within the ischemic core and in the glial scar. In contrast, TGF-β2 mRNA level was increased in neurons but not in astrocytes or microglial cells in layers II, III, and V of the ipsilateral cerebral cortex 24 h after MCAO. TGF-β3 was not induced in cells around the penumbra. Its expression increased in only a few cells in layer II of the cerebral cortex 24 h after MCAO. The levels of TGF-β2 and -β3 decreased at subsequent time points. Permanent MCAO further elevated the levels of all 3 subtypes of TGF-βs suggesting that reperfusion is not a major factor in their induction. TGF-β1 did not co-localize with either Fos or ATF-3, while the co-localization of TGF-β2 with Fos but not with ATF-3 suggests that cortical spreading depolarization, but not damage to neural processes, might be the mechanism of induction for TGF-β2. The results imply that endogenous TGF-βs are induced by different mechanisms following an ischemic attack in the brain suggesting that they are involved in distinct spatially and temporally regulated inflammatory and neuroprotective processes.
Collapse
Affiliation(s)
- Gabriella Pál
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Semmelweis University and the Hungarian Academy of Sciences, Budapest, Hungary
| | - Csilla Vincze
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Semmelweis University and the Hungarian Academy of Sciences, Budapest, Hungary
- Department of Neurology, Semmelweis University, Budapest, Hungary
| | - Éva Renner
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Semmelweis University and the Hungarian Academy of Sciences, Budapest, Hungary
| | - Edina A. Wappler
- Cardiovascular Center, Department Section of Vascular Neurology, Semmelweis University, Budapest, Hungary
- Department of Anesthesiology and Intensive Therapy, Semmelweis University, Budapest, Hungary
| | - Zoltán Nagy
- Cardiovascular Center, Department Section of Vascular Neurology, Semmelweis University, Budapest, Hungary
| | - Gábor Lovas
- Department of Neurology, Semmelweis University, Budapest, Hungary
- Department of Neurology, Jahn Ferenc Teaching Hospital, Budapest, Hungary
| | - Arpád Dobolyi
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Semmelweis University and the Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail:
| |
Collapse
|
13
|
The neuroprotective functions of transforming growth factor beta proteins. Int J Mol Sci 2012; 13:8219-8258. [PMID: 22942700 PMCID: PMC3430231 DOI: 10.3390/ijms13078219] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 05/24/2012] [Accepted: 06/19/2012] [Indexed: 12/26/2022] Open
Abstract
Transforming growth factor beta (TGF-β) proteins are multifunctional cytokines whose neural functions are increasingly recognized. The machinery of TGF-β signaling, including the serine kinase type transmembrane receptors, is present in the central nervous system. However, the 3 mammalian TGF-β subtypes have distinct distributions in the brain suggesting different neural functions. Evidence of their involvement in the development and plasticity of the nervous system as well as their functions in peripheral organs suggested that they also exhibit neuroprotective functions. Indeed, TGF-β expression is induced following a variety of types of brain tissue injury. The neuroprotective function of TGF-βs is most established following brain ischemia. Damage in experimental animal models of global and focal ischemia was shown to be attenuated by TGF-βs. In addition, support for their neuroprotective actions following trauma, sclerosis multiplex, neurodegenerative diseases, infections, and brain tumors is also accumulating. The review will also describe the potential mechanisms of neuroprotection exerted by TGF-βs including anti-inflammatory, -apoptotic, -excitotoxic actions as well as the promotion of scar formation, angiogenesis, and neuroregeneration. The participation of these mechanisms in the neuroprotective effects of TGF-βs during different brain lesions will also be discussed.
Collapse
|
14
|
Tichauer JE, von Bernhardi R. Transforming growth factor-β stimulates β amyloid uptake by microglia through Smad3-dependent mechanisms. J Neurosci Res 2012; 90:1970-80. [DOI: 10.1002/jnr.23082] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 03/25/2012] [Accepted: 04/13/2012] [Indexed: 12/28/2022]
|
15
|
von Bernhardi R, Eugenín J. Alzheimer's disease: redox dysregulation as a common denominator for diverse pathogenic mechanisms. Antioxid Redox Signal 2012; 16:974-1031. [PMID: 22122400 DOI: 10.1089/ars.2011.4082] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and a progressive neurodegeneration that appears to result from multiple pathogenic mechanisms (including protein misfolding/aggregation, involved in both amyloid β-dependent senile plaques and tau-dependent neurofibrillary tangles), metabolic and mitochondrial dysfunction, excitoxicity, calcium handling impairment, glial cell dysfunction, neuroinflammation, and oxidative stress. Oxidative stress, which could be secondary to several of the other pathophysiological mechanisms, appears to be a major determinant of the pathogenesis and progression of AD. The identification of oxidized proteins common for mild cognitive impairment and AD suggests that key oxidation pathways are triggered early and are involved in the initial progression of the neurodegenerative process. Abundant data support that oxidative stress, also considered as a main factor for aging, the major risk factor for AD, can be a common key element capable of articulating the divergent nature of the proposed pathogenic factors. Pathogenic mechanisms influence each other at different levels. Evidence suggests that it will be difficult to define a single-target therapy resulting in the arrest of progression or the improvement of AD deterioration. Since oxidative stress is present from early stages of disease, it appears as one of the main targets to be included in a clinical trial. Exploring the articulation of AD pathogenic mechanisms by oxidative stress will provide clues for better understanding the pathogenesis and progression of this dementing disorder and for the development of effective therapies to treat this disease.
Collapse
Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | |
Collapse
|
16
|
Duan B, Wang YZ, Yang T, Chu XP, Yu Y, Huang Y, Cao H, Hansen J, Simon RP, Zhu MX, Xiong ZG, Xu TL. Extracellular spermine exacerbates ischemic neuronal injury through sensitization of ASIC1a channels to extracellular acidosis. J Neurosci 2011; 31:2101-12. [PMID: 21307247 PMCID: PMC3101878 DOI: 10.1523/jneurosci.4351-10.2011] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 11/13/2010] [Accepted: 12/03/2010] [Indexed: 12/18/2022] Open
Abstract
Ischemic brain injury is a major problem associated with stroke. It has been increasingly recognized that acid-sensing ion channels (ASICs) contribute significantly to ischemic neuronal damage, but the underlying mechanism has remained elusive. Here, we show that extracellular spermine, one of the endogenous polyamines, exacerbates ischemic neuronal injury through sensitization of ASIC1a channels to extracellular acidosis. Pharmacological blockade of ASIC1a or deletion of the ASIC1 gene greatly reduces the enhancing effect of spermine in ischemic neuronal damage both in cultures of dissociated neurons and in a mouse model of focal ischemia. Mechanistically, spermine profoundly reduces desensitization of ASIC1a by slowing down desensitization in the open state, shifting steady-state desensitization to more acidic pH, and accelerating recovery between repeated periods of acid stimulation. Spermine-mediated potentiation of ASIC1a activity is occluded by PcTX1 (psalmotoxin 1), a specific ASIC1a inhibitor binding to its extracellular domain. Functionally, the enhanced channel activity is accompanied by increased acid-induced neuronal membrane depolarization and cytoplasmic Ca(2+) overload, which may partially explain the exacerbated neuronal damage caused by spermine. More importantly, blocking endogenous spermine synthesis significantly attenuates ischemic brain injury mediated by ASIC1a but not that by NMDA receptors. Thus, extracellular spermine contributes significantly to ischemic neuronal injury through enhancing ASIC1a activity. Our data suggest new neuroprotective strategies for stroke patients via inhibition of polyamine synthesis and subsequent spermine-ASIC interaction.
Collapse
Affiliation(s)
- Bo Duan
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yi-Zhi Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tao Yang
- Robert S. Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232
| | - Xiang-Ping Chu
- Robert S. Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232
| | - Ye Yu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu Huang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hui Cao
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jillian Hansen
- Robert S. Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232
| | - Roger P. Simon
- Robert S. Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia 30310, and
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Zhi-Gang Xiong
- Robert S. Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia 30310, and
| | - Tian-Le Xu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| |
Collapse
|
17
|
Vincze C, Pál G, Wappler EA, Szabó ER, Nagy ZG, Lovas G, Dobolyi A. Distribution of mRNAs encoding transforming growth factors-beta1, -2, and -3 in the intact rat brain and after experimentally induced focal ischemia. J Comp Neurol 2010; 518:3752-70. [PMID: 20653032 DOI: 10.1002/cne.22422] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transforming growth factors-beta1 (TGF-beta1), -2, and -3 form a small group of related proteins involved in the regulation of proliferation, differentiation, and survival of various cell types. Recently, TGF-betas were also demonstrated to be neuroprotective. In the present study, we investigated their distribution in the rat brain as well as their expression following middle cerebral artery occlusion. Probes were produced for all types of TGF-betas, and in situ hybridization was performed. We demonstrated high TGF-beta1 expression in cerebral cortex, hippocampus, central amygdaloid nucleus, medial preoptic area, hypothalamic paraventricular nucleus, substantia nigra, brainstem reticular formation and motoneurons, and area postrema. In contrast, TGF-beta2 was abundantly expressed in deep cortical layers, dentate gyrus, midline thalamic nuclei, posterior hypothalamic area and mamillary body, superior olive, areas of monoaminergic neurons, spinal trigeminal nucleus, dorsal vagal complex, cerebellum, and choroid plexus, and a high level of TGF-beta3 mRNA was found in cerebral cortex, hippocampus, basal amygdaloid nuclei, lateral septal nucleus, several thalamic nuclei, arcuate and supramamillary nuclei, superior colliculus, superior olive, brainstem reticular formation and motoneurons, area postrema, and inferior olive. Focal brain ischemia induced TGF-betas with markedly different expression patterns. TGF-beta1 was induced in the penumbral region of cortex and striatum, whereas TGF-beta2 and -beta3 were induced in different layers of the ipsilateral cortex. The expression of the subtypes of TGF-betas in different brain regions suggests that they are involved in the regulation of different neurons and bind to different latent TGF-beta binding proteins. Furthermore, they might have subtype-specific functions following ischemic attack.
Collapse
Affiliation(s)
- Csilla Vincze
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary
| | | | | | | | | | | | | |
Collapse
|