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Zhao R, Grunke SD, Wood CA, Perez GA, Comstock M, Li MH, Singh AK, Park KW, Jankowsky JL. Activity disruption causes degeneration of entorhinal neurons in a mouse model of Alzheimer's circuit dysfunction. eLife 2022; 11:e83813. [PMID: 36468693 PMCID: PMC9873254 DOI: 10.7554/elife.83813] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative diseases are characterized by selective vulnerability of distinct cell populations; however, the cause for this specificity remains elusive. Here, we show that entorhinal cortex layer 2 (EC2) neurons are unusually vulnerable to prolonged neuronal inactivity compared with neighboring regions of the temporal lobe, and that reelin + stellate cells connecting EC with the hippocampus are preferentially susceptible within the EC2 population. We demonstrate that neuronal death after silencing can be elicited through multiple independent means of activity inhibition, and that preventing synaptic release, either alone or in combination with electrical shunting, is sufficient to elicit silencing-induced degeneration. Finally, we discovered that degeneration following synaptic silencing is governed by competition between active and inactive cells, which is a circuit refinement process traditionally thought to end early in postnatal life. Our data suggests that the developmental window for wholesale circuit plasticity may extend into adulthood for specific brain regions. We speculate that this sustained potential for remodeling by entorhinal neurons may support lifelong memory but renders them vulnerable to prolonged activity changes in disease.
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Affiliation(s)
- Rong Zhao
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Stacy D Grunke
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Caleb A Wood
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Gabriella A Perez
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Melissa Comstock
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Ming-Hua Li
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Anand K Singh
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Kyung-Won Park
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
| | - Joanna L Jankowsky
- Department of Neuroscience, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
- Departments of Neurology, Neurosurgery, and Molecular and Cellular Biology, Huffington Center on Aging, Baylor College of MedicineHoustonUnited States
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Bojcevski J, Stojic A, Hoffmann DB, Williams SK, Müller A, Diem R, Fairless R. Influence of retinal NMDA receptor activity during autoimmune optic neuritis. J Neurochem 2020; 153:693-709. [PMID: 32031240 DOI: 10.1111/jnc.14980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/14/2020] [Accepted: 01/27/2020] [Indexed: 12/20/2022]
Abstract
Autoimmune optic neuritis (AON), a model of multiple sclerosis-associated optic neuritis, is accompanied by degeneration of retinal ganglion cells (RGCs) and optic nerve demyelination and axonal loss. In order to investigate the role of N-methyl-d-aspartate (NMDA) receptors in mediating RGC degeneration, upstream changes in the optic nerve actin cytoskeleton and associated deterioration in visual function, we induced AON in Brown Norway rats by immunization with myelin oligodendrocyte glycoprotein. Subsequently, visual acuity was assessed by recording visual evoked potentials and electroretinograms prior to extraction of optic nerves for western blot analysis and retinas for quantification of RGCs. As previously reported, in Brown Norway rats RGC degeneration is observed prior to onset of immune cell infiltration and demyelination of the optic nerves. However, within the optic nerve, destabilization of the actin cytoskeleton could be seen as indicated by an increase in the globular to filamentous actin ratio. Interestingly, these changes could be mimicked by intravitreal injection of glutamate, and similarly blocked by application of the NMDA receptor blocker MK-801, leading us to propose that prior to optic nerve lesion formation, NMDA receptor activation within the retina leads to retinal calcium accumulation, actin destabilization within the optic nerve as well as a deterioration of visual acuity during AON.
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Affiliation(s)
- Jovana Bojcevski
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Aleksandar Stojic
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Dorit B Hoffmann
- Department of Neurology, Saarland University, Homburg, Germany.,A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Sarah K Williams
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Andreas Müller
- Department of Diagnostic and Interventional Radiology, Saarland University, Homburg, Germany
| | - Ricarda Diem
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,CCU Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Centre (DKFZ), Heidelberg, Germany
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Hamdan H, Kockara NT, Jolly LA, Haun S, Wight PA. Control of human PLP1 expression through transcriptional regulatory elements and alternatively spliced exons in intron 1. ASN Neuro 2015; 7:7/1/1759091415569910. [PMID: 25694552 PMCID: PMC4342368 DOI: 10.1177/1759091415569910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
These authors contributed equally to this work. Although the myelin proteolipid protein gene (PLP1) encodes the most abundant protein in central nervous system (CNS) myelin, not much is known about the mechanisms that govern expression of the human gene (hPLP1). Much more is known about the processes that regulate Plp1 gene expression in rodents. From studies with Plp1-lacZ transgenic mice, it was determined that the first intron of mouse Plp1 (mPlp1) is required to attain high levels of expression in brain, concurrent with the active myelination period. Other studies have suggested that within mPlp1 intron 1 (>8 kb) lie several regions with enhancer-like activity. To test whether these sequences (and possibly others) in hPLP1 intron 1 are functional, deletion-transfection analysis was performed with hPLP1-lacZ constructs that contain various portions of the intron, or lack it altogether. Results presented here demonstrate the importance of hPLP1 intron 1 in achieving maximal levels of expression in the immortalized oligodendroglial cell line, Oli-neu. Deletion analysis indicates that the intron contains multiple positive regulatory elements which are active in Oli-neu cells. Some of these elements appear to be functionally conserved between human and mouse, while others are not. Furthermore, our studies demonstrate that multiple splice variants can be formed due to inclusion of extra (supplementary) exons from what is classically thought of as hPLP1 intron 1. Thus, splicing of these novel exons (which are not recognized as such in mPlp1 due to lack of conserved splice sites) must utilize factors common to both human and mouse since Oli-neu cells are of mouse origin.
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Affiliation(s)
- Hamdan Hamdan
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Neriman T Kockara
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Lee Ann Jolly
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Shirley Haun
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Patricia A Wight
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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van de Looij Y, Ginet V, Chatagner A, Toulotte A, Somm E, Hüppi PS, Sizonenko SV. Lactoferrin during lactation protects the immature hypoxic-ischemic rat brain. Ann Clin Transl Neurol 2014; 1:955-67. [PMID: 25574471 PMCID: PMC4284122 DOI: 10.1002/acn3.138] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 12/13/2022] Open
Abstract
Objective Lactoferrin (Lf) is an iron-binding glycoprotein secreted in maternal milk presenting anti-inflammatory and antioxidant properties. It shows efficient absorption into the brain from nutritional source. Brain injury frequently resulting from cerebral hypoxia-ischemia (HI) has a high incidence in premature infants with ensuing neurodevelopmental disabilities. We investigated the neuroprotective effect of maternal nutritional supplementation with Lf during lactation in a rat model of preterm HI brain injury using magnetic resonance imaging (MRI), brain gene, and protein expression. Methods Moderate brain HI was induced using unilateral common carotid artery occlusion combined with hypoxia (6%, 30 min) in the postnatal day 3 (P3) rat brain (24–28 weeks human equivalent). High-field multimodal MRI techniques were used to investigate the effect of maternal Lf supplementation through lactation. Expression of cytokine coding genes (TNF-α and IL-6), the prosurvival/antiapoptotic AKT protein and caspase-3 activation were also analyzed in the acute phase after HI. Results MRI analysis demonstrated reduced cortical injury in Lf rats few hours post-HI and in long-term outcome (P25). Lf reduced HI-induced modifications of the cortical metabolism and altered white matter microstructure was recovered in Lf-supplemented rats at P25. Lf supplementation significantly decreased brain TNF-α and IL-6 gene transcription, increased phosphorylated AKT levels and reduced activation of caspase-3 at 24 h post-injury. Interpretation Lf given through lactation to rat pups with cerebral HI injury shows neuroprotective effects on brain metabolism, and cerebral gray and white matter recovery. This nutritional intervention may be of high interest for the clinical field of preterm brain neuroprotection.
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Affiliation(s)
- Yohan van de Looij
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland ; Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL) Lausanne, Switzerland
| | - Vanessa Ginet
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland
| | - Alexandra Chatagner
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland
| | - Audrey Toulotte
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland
| | - Emmanuel Somm
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland
| | - Petra S Hüppi
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland
| | - Stéphane V Sizonenko
- Division of Child Development and Growth, Department of Pediatrics, University of Geneva Geneva, Switzerland
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Isoflurane-induced apoptosis of neurons and oligodendrocytes in the fetal rhesus macaque brain. Anesthesiology 2014; 120:626-38. [PMID: 24158051 DOI: 10.1097/aln.0000000000000037] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND The authors have previously shown that exposure of the neonatal nonhuman primate (NHP) brain to isoflurane for 5 h causes widespread acute apoptotic degeneration of neurons and oligodendrocyte. The current study explored the potential apoptogenic action of isoflurane in the fetal NHP brain. METHODS Fetal rhesus macaques at gestational age of 120 days (G120) were exposed in utero for 5 h to isoflurane anesthesia (n = 5) or to no anesthesia (control condition; n = 4), and all regions of the brain were systematically evaluated 3 h later for evidence of apoptotic degeneration of neurons or glia. RESULTS Exposure of the G120 fetal NHP brain to isoflurane caused a significant increase in apoptosis of neurons and of oligodendrocytes at a stage when oligodendrocytes were just beginning to myelinate axons. The neuroapoptosis response was most prominent in the cerebellum, caudate, putamen, amygdala, and several cerebrocortical regions. Oligodendrocyte apoptosis was diffusely distributed over many white matter regions. The total number of apoptotic profiles (neurons + oligodendrocytes) in the isoflurane-exposed brains was increased 4.1-fold, compared with the brains from drug-naive controls. The total number of oligodendrocytes deleted by isoflurane was higher than the number of neurons deleted. CONCLUSIONS Isoflurane anesthesia for 5 h causes death of neurons and oligodendrocytes in the G120 fetal NHP brain. In the fetal brain, as the authors previously found in the neonatal NHP brain, oligodendrocytes become vulnerable when they are just achieving myelination competence. The neurotoxic potential of isoflurane increases between the third trimester (G120) and the neonatal period in the NHP brain.
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Creeley C, Dikranian K, Dissen G, Martin L, Olney J, Brambrink A. Propofol-induced apoptosis of neurones and oligodendrocytes in fetal and neonatal rhesus macaque brain. Br J Anaesth 2013; 110 Suppl 1:i29-38. [PMID: 23722059 DOI: 10.1093/bja/aet173] [Citation(s) in RCA: 270] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Exposure of the fetal or neonatal non-human primate (NHP) brain to isoflurane or ketamine for 5 h causes widespread apoptotic degeneration of neurones, and exposure to isoflurane also causes apoptotic degeneration of oligodendrocytes (OLs). The present study explored the apoptogenic potential of propofol in the fetal and neonatal NHP brain. METHOD Fetal rhesus macaques at gestational age 120 days were exposed in utero, or postnatal day 6 rhesus neonates were exposed directly for 5 h to propofol anaesthesia (n=4 fetuses; and n=4 neonates) or to no anaesthesia (n=4 fetuses; n=5 neonates), and the brains were systematically evaluated 3 h later for evidence of apoptotic degeneration of neurones or glia. RESULTS Exposure of fetal or neonatal NHP brain to propofol caused a significant increase in apoptosis of neurones, and of OLs at a stage when OLs were just beginning to myelinate axons. Apoptotic degeneration affected similar brain regions but to a lesser extent than we previously described after isoflurane. The number of OLs affected by propofol was approximately equal to the number of neurones affected at both developmental ages. In the fetus, neuroapoptosis affected particularly subcortical and caudal regions, while in the neonate injury involved neocortical regions in a distinct laminar pattern and caudal brain regions were less affected. CONCLUSIONS Propofol anaesthesia for 5 h caused death of neurones and OLs in both the fetal and neonatal NHP brain. OLs become vulnerable to the apoptogenic action of propofol when they are beginning to achieve myelination competence.
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Affiliation(s)
- C Creeley
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
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Creeley CE, Dikranian KT, Johnson SA, Farber NB, Olney JW. Alcohol-induced apoptosis of oligodendrocytes in the fetal macaque brain. Acta Neuropathol Commun 2013; 1:23. [PMID: 24252271 PMCID: PMC3893424 DOI: 10.1186/2051-5960-1-23] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 04/02/2013] [Indexed: 02/08/2023] Open
Abstract
Background In utero exposure of the fetal non-human primate (NHP) brain to alcohol on a single occasion during early or late third-trimester gestation triggers widespread acute apoptotic death of cells in both gray and white matter (WM) regions of the fetal brain. In a prior publication, we documented that the dying gray matter cells are neurons, and described the regional distribution and magnitude of this cell death response. Here, we present new findings regarding the magnitude, identity and maturational status of the dying WM cells in these alcohol-exposed fetal NHP brains. Results Our findings document that the dying WM cells belong to the oligodendrocyte (OL) lineage. OLs become vulnerable when they are just beginning to generate myelin basic protein in preparation for myelinating axons, and they remain vulnerable throughout later stages of myelination. We found no evidence linking astrocytes, microglia or OL progenitors to this WM cell death response. The mean density (profiles per mm3) of dying WM cells in alcohol-exposed brains was 12.7 times higher than the mean density of WM cells dying by natural apoptosis in drug-naive control brains. Conclusions In utero exposure of the fetal NHP brain to alcohol on a single occasion triggers widespread acute apoptotic death of neurons (previous study) and of OLs (present study) throughout WM regions of the developing brain. The rate of OL apoptosis in alcohol-exposed brains was 12.7 times higher than the natural OL apoptosis rate. OLs become sensitive to the apoptogenic action of alcohol when they are just beginning to generate constituents of myelin in their cytoplasm, and they remain vulnerable throughout later stages of myelination. There is growing evidence for a similar apoptotic response of both neurons and OLs following exposure of the developing brain to anesthetic and anticonvulsant drugs. Collectively, this body of evidence raises important questions regarding the role that neuro and oligo apoptosis may play in the human condition known as fetal alcohol spectrum disorder (FASD), and also poses a question whether other apoptogenic drugs, although long considered safe for pediatric/obstetric use, may have the potential to cause iatrogenic FASD-like developmental disability syndromes.
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Koeglsperger T, Li S, Brenneis C, Saulnier JL, Mayo L, Carrier Y, Selkoe DJ, Weiner HL. Impaired glutamate recycling and GluN2B-mediated neuronal calcium overload in mice lacking TGF-β1 in the CNS. Glia 2013; 61:985-1002. [PMID: 23536313 DOI: 10.1002/glia.22490] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 02/06/2013] [Indexed: 12/14/2022]
Abstract
Transforming growth factor β1 (TGF-β1) is a pleiotropic cytokine expressed throughout the CNS. Previous studies demonstrated that TGF-β1 contributes to maintain neuronal survival, but mechanistically this effect is not well understood. We generated a CNS-specific TGF-β1-deficient mouse model to investigate the functional consequences of TGF-β1-deficiency in the adult mouse brain. We found that depletion of TGF-β1 in the CNS resulted in a loss of the astrocyte glutamate transporter (GluT) proteins GLT-1 (EAAT2) and GLAST (EAAT1) and decreased glutamate uptake in the mouse hippocampus. Treatment with TGF-β1 induced the expression of GLAST and GLT-1 in cultured astrocytes and enhanced astroglial glutamate uptake. Similar to GLT-1-deficient mice, CNS-TGF-β1-deficient mice had reduced brain weight and neuronal loss in the CA1 hippocampal region. CNS-TGF-β1-deficient mice showed GluN2B-dependent aberrant synaptic plasticity in the CA1 area of the hippocampus similar to the glutamate transport inhibitor DL-TBOA and these mice were highly sensitive to excitotoxic injury. In addition, hippocampal neurons from TGF-β1-deficient mice had elevated GluN2B-mediated calcium signals in response to extrasynaptic glutamate receptor stimulation, whereas cells treated with TGF-β1 exhibited reduced GluN2B-mediated calcium signals. In summary, our study demonstrates a previously unrecognized function of TGF-β1 in the CNS to control extracellular glutamate homeostasis and GluN2B-mediated calcium responses in the mouse hippocampus.
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Affiliation(s)
- Thomas Koeglsperger
- Department of Neurology, Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Hendrickson ML, Ling C, Kalil RE. Degeneration of axotomized projection neurons in the rat dLGN: temporal progression of events and their mitigation by a single administration of FGF2. PLoS One 2012; 7:e46918. [PMID: 23144793 PMCID: PMC3489851 DOI: 10.1371/journal.pone.0046918] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 09/06/2012] [Indexed: 12/13/2022] Open
Abstract
Removal of visual cortex in the rat axotomizes projection neurons in the dorsal lateral geniculate nucleus (dLGN), leading to cytological and structural changes and apoptosis. Biotinylated dextran amine was injected into the visual cortex to label dLGN projection neurons retrogradely prior to removing the cortex in order to quantify the changes in the dendritic morphology of these neurons that precede cell death. At 12 hours after axotomy we observed a loss of appendages and the formation of varicosities in the dendrites of projection neurons. During the next 7 days, the total number of dendrites and the cross-sectional areas of the dendritic arbors of projection neurons declined to about 40% and 20% of normal, respectively. The response of dLGN projection neurons to axotomy was asynchronous, but the sequence of structural changes in individual neurons was similar; namely, disruption of dendrites began within hours followed by cell soma atrophy and nuclear condensation that commenced after the loss of secondary dendrites had occurred. However, a single administration of fibroblast growth factor-2 (FGF2), which mitigates injury-induced neuronal cell death in the dLGN when given at the time of axotomy, markedly reduced the dendritic degeneration of projection neurons. At 3 and 7 days after axotomy the number of surviving dendrites of dLGN projection neurons in FGF-2 treated rats was approximately 50% greater than in untreated rats, and the cross-sectional areas of dendritic arbors were approximately 60% and 50% larger. Caspase-3 activity in axotomized dLGN projection neurons was determined by immunostaining for fractin (fractin-IR), an actin cleavage product produced exclusively by activated caspase-3. Fractin-IR was seen in some dLGN projection neurons at 36 hours survival, and it increased slightly by 3 days. A marked increase in reactivity was seen by 7 days, with the entire dLGN filled with dense fractin-IR in neuronal cell somas and dendrites.
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Affiliation(s)
- Michael L. Hendrickson
- W.M. Keck Laboratory for Biological Imaging, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Changying Ling
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ronald E. Kalil
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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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: 173] [Impact Index Per Article: 14.4] [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.
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Bakhshayesh M, Zaker F, Hashemi M, Katebi M, Solaimani M. TGF- β1-mediated apoptosis associated with SMAD-dependent mitochondrial Bcl-2 expression. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2012; 12:138-43. [PMID: 22297256 DOI: 10.1016/j.clml.2011.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 11/20/2011] [Accepted: 12/01/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND Transforming growth factor (TGF) β1 can elicit various cellular responses, including inhibition of cell growth, migration, differentiation, and apoptosis. In addition, TGF-β1 is able to induce apoptosis in certain lymphomas. METHODS In the present study, the role of SMADs, Bax, Bcl-xl, and Bcl2 was characterized in 2 B-lymphoma cell lines, Burkitt and pre-B cell. RESULTS Apoptosis was detected after exposure of TGF-β on Raji and Nalm 6 cell lines and was evaluated by flow cytometry by using annexin V, reverse transcriptase-polymerase chain reaction, and Western blot analysis. Flow Cytometry With Cell Sorting analysis showed that apoptosis could be observed after 24 hours of TGF-β treatment and was continued after 48 hours. TGF-β downregulated the Bcl-xl and Bcl-2, whereas the Bax was upregulated. Furthermore, messenger RNA of SMAD6 and SMAD7 showed the significant upregulation. CONCLUSION The results indicated that alteration in gene expression and protein level may determine the induction of apoptosis pathway in these lymphoma cell lines exposed to TGF-β.
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Affiliation(s)
- Masoomeh Bakhshayesh
- Cellular and Molecular Research Centre, Tehran University of Medical Sciences, Tehran, Iran.
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Gary DS, Malone M, Capestany P, Houdayer T, McDonald JW. Electrical stimulation promotes the survival of oligodendrocytes in mixed cortical cultures. J Neurosci Res 2011; 90:72-83. [PMID: 21932370 DOI: 10.1002/jnr.22717] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/09/2011] [Accepted: 05/19/2011] [Indexed: 11/07/2022]
Abstract
Oligodendrocyte (OLG) death plays a major role in white matter dysfunction and demyelination following injury to the CNS. Axonal contact, communication, and neuronal activity appear to promote OLG survival and function in cell culture and during development. The application of electrical stimulation to mixed neural cultures has been shown to promote OLG differentiation and the formation of myelin in vitro. Here we show that OLG viability can be significantly enhanced in mixed cortical cultures by applying biphasic pulses of electrical stimulation (ESTIM). Enhanced survival via ESTIM requires the presence of neurons and is suppressed by inhibition of voltage-gated sodium channels. Additionally, contact between the axon and OLG is necessary for ESTIM to promote OLG survival. This report suggests that patterned neuronal activity could repress delayed progression of white matter injury and promote CNS repair in neurological conditions that involve white matter damage.
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Affiliation(s)
- Devin S Gary
- The International Center for Spinal Cord Injury, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland 21205, USA.
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Hicks SD, Miller MW. Effects of ethanol on transforming growth factor Β1-dependent and -independent mechanisms of neural stem cell apoptosis. Exp Neurol 2011; 229:372-80. [PMID: 21419121 DOI: 10.1016/j.expneurol.2011.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 02/11/2011] [Accepted: 03/07/2011] [Indexed: 01/24/2023]
Abstract
Stem cell vitality is critical for the growth of the developing brain. Growth factors can define the survival of neural stem cells (NSCs) and ethanol can affect growth factor-mediated activities. The present study tested two hypotheses: (a) ethanol causes the apoptotic death of NSCs and (b) this effect is influenced by the ambient growth factor. Monolayer cultures of non-immortalized NS-5 cells were exposed to fibroblast growth factor (FGF) 2 or transforming growth factor (TGF) β1 in the absence or presence of ethanol for 48 h. Ethanol killed NSCs as measured by increases in the numbers of ethidium bromide+ and annexin V+ cells and decreases in the number of calcein AM+ (viable) cells. These toxic effects were promoted by TGFβ1. A quantitative polymerase chain reaction array of apoptosis-related mRNAs revealed an ethanol-induced increase (≥2-fold change; p<0.05) in transcripts involved in Fas ligand (FasL) and tumor necrosis factor (TNF) signaling. These effects, particularly the FasL pathway, were potentiated by TGFβ1. Immunocytochemical analyses of NS-5 cells showed that transcriptional alterations translated into consistent up-regulation of protein expression. Experiments with the neocortical proliferative zones harvested from fetal mice exposed to ethanol showed that ethanol activated similar molecular systems in vivo. Thus, ethanol induces NSC death through two distinct molecular mechanisms, one is initiated by TGFβ1 (FasL) and another (through TNF) which is TGFβ1-independent.
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Affiliation(s)
- Steven D Hicks
- Department of Neuroscience and Physiology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA
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