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Martín-Montañez E, Millon C, Boraldi F, Garcia-Guirado F, Pedraza C, Lara E, Santin LJ, Pavia J, Garcia-Fernandez M. IGF-II promotes neuroprotection and neuroplasticity recovery in a long-lasting model of oxidative damage induced by glucocorticoids. Redox Biol 2017; 13:69-81. [PMID: 28575743 PMCID: PMC5454142 DOI: 10.1016/j.redox.2017.05.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 05/23/2017] [Indexed: 11/05/2022] Open
Abstract
Insulin-like growth factor-II (IGF-II) is a naturally occurring hormone that exerts neurotrophic and neuroprotective properties in a wide range of neurodegenerative diseases and ageing. Accumulating evidence suggests that the effects of IGF-II in the brain may be explained by its binding to the specific transmembrane receptor, IGFII/M6P receptor (IGF-IIR). However, relatively little is known regarding the role of IGF-II through IGF-IIR in neuroprotection. Here, using adult cortical neuronal cultures, we investigated whether IGF-II exhibits long-term antioxidant effects and neuroprotection at the synaptic level after oxidative damage induced by high and transient levels of corticosterone (CORT). Furthermore, the involvement of the IGF-IIR was also studied to elucidate its role in the neuroprotective actions of IGF-II. We found that neurons treated with IGF-II after CORT incubation showed reduced oxidative stress damage and recovered antioxidant status (normalized total antioxidant status, lipid hydroperoxides and NAD(P) H:quinone oxidoreductase activity). Similar results were obtained when mitochondria function was analysed (cytochrome c oxidase activity, mitochondrial membrane potential and subcellular mitochondrial distribution). Furthermore, neuronal impairment and degeneration were also assessed (synaptophysin and PSD-95 expression, presynaptic function and FluoroJade B® stain). IGF-II was also able to recover the long-lasting neuronal cell damage. Finally, the effects of IGF-II were not blocked by an IGF-IR antagonist, suggesting the involvement of IGF-IIR. Altogether these results suggest that, in or model, IGF-II through IGF-IIR is able to revert the oxidative damage induced by CORT. In accordance with the neuroprotective role of the IGF-II/IGF-IIR reported in our study, pharmacotherapy approaches targeting this pathway may be useful for the treatment of diseases associated with cognitive deficits (i.e., neurodegenerative disorders, depression, etc.). First evidence that IGF-II reverts oxidative synaptic damage produced by corticoids. IGF-II recovers mitochondrial function in synapses after oxidative damage. IGF-II restores mitochondrial distribution in neurons after oxidative damage. Evidence of the involvement of IGF-II receptor in the recovery of synaptic function. IGF-II reverts neurodegeneration induced by oxidative damage produced by corticoids.
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Affiliation(s)
- E Martín-Montañez
- Department of Pharmacology and Paediatrics, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain
| | - C Millon
- Department of Human Physiology, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain
| | - F Boraldi
- Department of Life Sciences, University of Modena e Reggio Emilia, Modena, Italy
| | - F Garcia-Guirado
- Department of Human Physiology, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain
| | - C Pedraza
- Department of Psychobiology, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain
| | - E Lara
- Department of Human Physiology, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain
| | - L J Santin
- Department of Psychobiology, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain
| | - J Pavia
- Department of Pharmacology and Paediatrics, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain.
| | - M Garcia-Fernandez
- Department of Human Physiology, Málaga University, Biomedical Research Institute of Málaga (IBIMA), Málaga, Spain.
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Najem D, Bamji-Mirza M, Chang N, Liu QY, Zhang W. Insulin resistance, neuroinflammation, and Alzheimer's disease. Rev Neurosci 2015; 25:509-25. [PMID: 24622783 DOI: 10.1515/revneuro-2013-0050] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 02/13/2014] [Indexed: 01/02/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Pathologically, it is characterized by degeneration of neurons and synapses, the deposition of extracellular plaques consisting of aggregated amyloid-β (Aβ) peptides, and intracellular neurofibrillary tangles made up of hyperphosphorylated tau protein. Recently, the spotlights have been centered on two characteristics of AD, neuroinflammation and insulin resistance. Because both of these pathways play roles in synaptic dysfunction and neurodegeneration, they become potential targets for therapeutic intervention that could impede the progression of the disease. Here, we present an overview of the traditional amyloid hypothesis, as well as emerging data on both inflammatory and impaired insulin signaling pathways in AD. It becomes evident that more than one concurrent treatment can be synergistic and various combinations should be discussed as a potential therapeutic strategy to correct the anomalies in AD. Insulin resistance, Aβ/tau pathologies, neuroinflammation, and dysregulation of central nervous system homeostasis are intertwined processes that together create the complex pathology of AD and should be considered as a whole picture.
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3
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Something old, something new and something borrowed: emerging paradigm of insulin-like growth factor type 1 receptor (IGF-1R) signaling regulation. Cell Mol Life Sci 2013; 71:2403-27. [PMID: 24276851 PMCID: PMC4055838 DOI: 10.1007/s00018-013-1514-y] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 10/17/2013] [Accepted: 11/07/2013] [Indexed: 12/14/2022]
Abstract
The insulin-like growth factor type 1 receptor (IGF-1R) plays a key role in the development and progression of cancer; however, therapeutics targeting it have had disappointing results in the clinic. As a receptor tyrosine kinase (RTK), IGF-1R is traditionally described as an ON/OFF system, with ligand stabilizing the ON state and exclusive kinase-dependent signaling activation. Newly added to the traditional model, ubiquitin-mediated receptor downregulation and degradation was originally described as a response to ligand/receptor interaction and thus inseparable from kinase signaling activation. Yet, the classical model has proven over-simplified and insufficient to explain experimental evidence accumulated over the last decade, including kinase-independent signaling, unbalanced signaling, or dissociation between signaling and receptor downregulation. Based on the recent findings that IGF-1R “borrows” components of G-protein coupled receptor (GPCR) signaling, including β-arrestins and G-protein-related kinases, we discuss the emerging paradigm for the IGF-1R as a functional RTK/GPCR hybrid, which integrates the kinase signaling with the IGF-1R canonical GPCR characteristics. The contradictions to the classical IGF-1R signaling concept as well as the design of anti-IGF-1R therapeutics treatment are considered in the light of this paradigm shift and we advocate recognition of IGF-1R as a valid target for cancer treatment.
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Romanelli RJ, LeBeau AP, Fulmer CG, Lazzarino DA, Hochberg A, Wood TL. Insulin-like Growth Factor Type-I Receptor Internalization and Recycling Mediate the Sustained Phosphorylation of Akt. J Biol Chem 2007; 282:22513-24. [PMID: 17545147 DOI: 10.1074/jbc.m704309200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously we demonstrated that insulin-like growth factor-I mediates the sustained phosphorylation of Akt, which is essential for long term survival and protection of glial progenitors from glutamate toxicity. These prosurvival effects correlated with prolonged activation and stability of the insulin-like growth factor type-I receptor. In the present study, we investigated the mechanisms whereby insulin-like growth factor-I signaling, through the insulin-like growth factor type-I receptor, mediates the sustained phosphorylation of Akt. We showed that insulin-like growth factor-I stimulation induced loss of receptors from the cell surface but that surface receptors recovered over time. Blocking receptor internalization inhibited Akt phosphorylation, whereas inhibition of receptor trafficking blocked receptor recovery at the cell surface and the sustained phosphorylation of Akt. Moreover the insulin-like growth factor type-I receptor localized with the transferrin receptor and Rab11-positive endosomes in a ligand-dependent manner, further supporting the conclusion that this receptor follows a recycling pathway. Our results provide evidence that ligand stimulation leads to internalization of the insulin-like growth factor type-I receptor, which mediates Akt phosphorylation, and that receptor recycling sustains Akt phosphorylation in glial progenitors. Mathematical modeling of receptor trafficking further supports these results and predicts an additional kinetic state of the receptor consistent with sustained Akt phosphorylation.
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Affiliation(s)
- Robert J Romanelli
- Department of Neurology and Neurosciences, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA
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5
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Tai CY, Mysore SP, Chiu C, Schuman EM. Activity-Regulated N-Cadherin Endocytosis. Neuron 2007; 54:771-85. [PMID: 17553425 DOI: 10.1016/j.neuron.2007.05.013] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 03/23/2007] [Accepted: 05/09/2007] [Indexed: 11/25/2022]
Abstract
Enduring forms of synaptic plasticity are thought to require ongoing regulation of adhesion molecules, such as N-cadherin, at synaptic junctions. Little is known about the activity-regulated trafficking of adhesion molecules. Here we demonstrate that surface N-cadherin undergoes a surprisingly high basal rate of internalization. Upon activation of NMDA receptors (NMDAR), the rate of N-cadherin endocytosis is significantly reduced, resulting in an accumulation of N-cadherin in the plasma membrane. Beta-catenin, an N-cadherin binding partner, is a primary regulator of N-cadherin endocytosis. Following NMDAR stimulation, beta-catenin accumulates in spines and exhibits increased binding to N-cadherin. Overexpression of a mutant form of beta-catenin, Y654F, prevents the NMDAR-dependent regulation of N-cadherin internalization, resulting in stabilization of surface N-cadherin molecules. Furthermore, the stabilization of surface N-cadherin blocks NMDAR-dependent synaptic plasticity. These results indicate that NMDAR activity regulates N-cadherin endocytosis, providing a mechanistic link between structural plasticity and persistent changes in synaptic efficacy.
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Affiliation(s)
- Chin-Yin Tai
- Division of Biology 114-96, California Institute of Technology, Pasadena, CA 91125, USA
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6
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Boksa P, Zhang Y, Amritraj A, Kar S. Birth insults involving hypoxia produce long-term increases in hippocampal [125I]insulin-like growth factor-I and -II receptor binding in the rat. Neuroscience 2006; 139:451-62. [PMID: 16448776 DOI: 10.1016/j.neuroscience.2005.12.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Revised: 12/05/2005] [Accepted: 12/12/2005] [Indexed: 02/07/2023]
Abstract
Insulin-like growth factors-I and -II and insulin are structurally related mitogenic growth factors with multiple actions in the developing nervous system and adult CNS. Previous studies have demonstrated acute induction of insulin-like growth factors and their receptors, over a time course of several days, in response to hypoxic/ischemic insult to developing or adult brain. The current study tested whether birth insults involving hypoxia may produce long term changes in brain insulin-like growth factor or insulin receptor levels, lasting into adulthood. For this, rats were born vaginally (controls), by cesarean section, or by cesarean section with 15 min of added global anoxia (cesarean section+anoxia), and brain [125I]insulin-like growth factor-I, [125I]insulin-like growth factor-II and [125I]insulin receptor binding sites were assessed autoradiographically at adulthood. [125I]Insulin-like growth factor-I receptor binding sites were increased in all hippocampal subfields (CA1-CA3, dentate gyrus) in rats born either by cesarean section or by cesarean section+anoxia, compared with vaginal birth. [125I]Insulin-like growth factor-II binding was increased in all hippocampal subfields only in rats born by cesarean section+anoxia compared with either vaginal birth or cesarean section groups. [125I]Insulin-like growth factor-I and [125I]insulin-like growth factor-II binding in frontal cortex, striatum and cerebellum were unaffected by birth group, except for increased [125I]insulin-like growth factor-I binding in the cerebellar molecular layer of cesarean-sectioned animals. Birth group had no significant effect on [125I]insulin binding in any brain region. Affinity cross-linking experiments performed with hippocampal membranes from the three birth groups showed that i) [125I]insulin-like growth factor-I and [125I]insulin-like growth factor-II recognized bands of molecular weights characteristic of insulin-like growth factor-I and insulin-like growth factor-II receptors, respectively, and ii) [125I]insulin-like growth factor-I and [125I]insulin-like growth factor-II were displaced more potently by their respective unlabeled ligands than by related molecules. It is concluded that birth insults involving hypoxia can induce lasting increases in insulin-like growth factor-I and -II receptors in the CNS. There is specificity with respect to the subtype of insulin-like growth factor receptor affected by the particular birth insult and the brain region affected. It is suggested that enduring increases in levels of insulin-like growth factor receptors consequent to hypoxic birth insult may help to maintain hippocampal function at adulthood, and could modulate responsiveness to insulin-like growth factor administration.
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Affiliation(s)
- P Boksa
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, 6875 LaSalle Boulevard, Verdun, Quebec, Canada H4H 1R3
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7
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Russo VC, Gluckman PD, Feldman EL, Werther GA. The insulin-like growth factor system and its pleiotropic functions in brain. Endocr Rev 2005; 26:916-43. [PMID: 16131630 DOI: 10.1210/er.2004-0024] [Citation(s) in RCA: 355] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In recent years, much interest has been devoted to defining the role of the IGF system in the nervous system. The ubiquitous IGFs, their cell membrane receptors, and their carrier binding proteins, the IGFBPs, are expressed early in the development of the nervous system and are therefore considered to play a key role in these processes. In vitro studies have demonstrated that the IGF system promotes differentiation and proliferation and sustains survival, preventing apoptosis of neuronal and brain derived cells. Furthermore, studies of transgenic mice overexpressing components of the IGF system or mice with disruptions of the same genes have clearly shown that the IGF system plays a key role in vivo.
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Affiliation(s)
- V C Russo
- Centre for Hormone Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia.
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8
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Payne AM, Zheng Z, Messi ML, Milligan CE, González E, Delbono O. Motor neurone targeting of IGF-1 prevents specific force decline in ageing mouse muscle. J Physiol 2005; 570:283-94. [PMID: 16293644 PMCID: PMC1464304 DOI: 10.1113/jphysiol.2005.100032] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
IGF-1 is a potent growth factor for both motor neurones and skeletal muscle. Muscle IGF-1 is known to provide target-derived trophic effects on motor neurones. Therefore, IGF-1 overexpression in muscle is effective in delaying or preventing deleterious effects of ageing in both tissues. Since age-related decline in muscle function stems partly from motor neurone loss, a tetanus toxin fragment-C (TTC) fusion protein was created to target IGF-1 to motor neurones. IGF-1-TTC retains IGF-1 activity as indicated by [(3)H]thymidine incorporation into L6 myoblasts. Spinal cord motor neurones effectively bound and internalized the IGF-1-TTC in vitro. Similarly, IGF-1-TTC injected into skeletal muscles was taken up and retrogradely transported to the spinal cord in vivo, a process prevented by denervation of injected muscles. Three monthly IGF-1-TTC injections into muscles of ageing mice did not increase muscle weight or muscle fibre size, but significantly increased single fibre specific force over aged controls injected with saline, IGF-1, or TTC. None of the injections changed muscle fibre type composition, but neuromuscular junction post-terminals were larger and more complex in muscle fibres injected with IGF-1-TTC, compared to the other groups, suggesting preservation of muscle fibre innervation. This work demonstrates that induced overexpression of IGF-1 in spinal cord motor neurones of ageing mice prevents muscle fibre specific force decline, a hallmark of ageing skeletal muscle.
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Affiliation(s)
- Anthony M Payne
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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9
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El-Bakri NK, Islam A, Suliman I, Lindgren U, Winblad B, Adem A. Ovariectomy and gonadal hormone treatment: effects on insulin-like growth factor-1 receptors in the rat brain. Growth Horm IGF Res 2004; 14:388-393. [PMID: 15336232 DOI: 10.1016/j.ghir.2004.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 04/27/2004] [Accepted: 04/28/2004] [Indexed: 02/04/2023]
Abstract
Various studies demonstrate that estradiol regulates structure and function of adult neurons. Long-term effect of estradiol in terms of neuroprotection is less documented compared to short-term one. It is well documented that estradiol interacts with insulin-like growth factor-1 (IGF-I) in the brain. The present study examines the effect of ovariectomy and two doses of ovarian hormone treatment on IGF-I receptor density in the adult rat by receptor autoradiography using (125)I-IGF-I as a ligand. Our result showed that ovariectomy decreased IGF-I receptor density in hippocampus, hypothalamus and parietal cortex compared to that of the sham-operated group. Treatment with low or high dose estrogen restored IGF-I receptor density to the control levels in nearly all areas studied in this investigation. It seems that low dose estrogen has more pronounced effect than the high dose in restoring IGF-I receptor density. On the other hand, progesterone treatment in high but not in low dose restored IGF-I receptor density to that of the control. These results demonstrate that both estrogen and progesterone significantly affects IGF-I receptor density in different areas of the brain. These effects indicate a dose-dependent modulator effect of ovarian hormones on IGF-I activity in the brain.
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Affiliation(s)
- Nahid K El-Bakri
- Neurotec, Section of Experimental Geriatrics, Karolinska Institute, Huddinge University Hospital, B-84 S-141 86 Huddinge, Sweden.
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10
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Dickson TC, Mintz CD, Benson DL, Salton SRJ. Functional binding interaction identified between the axonal CAM L1 and members of the ERM family. J Cell Biol 2002; 157:1105-12. [PMID: 12070130 PMCID: PMC2173555 DOI: 10.1083/jcb.200111076] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A yeast two-hybrid library was screened using the cytoplasmic domain of the axonal cell adhesion molecule L1 to identify binding partners that may be involved in the regulation of L1 function. The intracellular domain of L1 bound to ezrin, a member of the ezrin, radixin, and moesin (ERM) family of membrane-cytoskeleton linking proteins, at a site overlapping that for AP2, a clathrin adaptor. Binding of bacterial fusion proteins confirmed this interaction. To determine whether ERM proteins interact with L1 in vivo, extracellular antibodies to L1 were used to force cluster the protein on cultured hippocampal neurons and PC12 cells, which were then immunolabeled for ERM proteins. Confocal analysis revealed a precise pattern of codistribution between ERMs and L1 clusters in axons and PC12 neurites, whereas ERMs in dendrites and spectrin labeling remained evenly distributed. Transfection of hippocampal neurons grown on an L1 substrate with a dominant negative ERM construct resulted in extensive and abnormal elaboration of membrane protrusions and an increase in axon branching, highlighting the importance of the ERM-actin interaction in axon development. Together, our data indicate that L1 binds directly to members of the ERM family and suggest this association may coordinate aspects of axonal morphogenesis.
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Affiliation(s)
- Tracey C Dickson
- Fishberg Research Center for Neurobiology, The Mount Sinai School of Medicine, New York, NY 10029, USA
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11
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Zheng WH, Kar S, Doré S, Quirion R. Insulin-like growth factor-1 (IGF-1): a neuroprotective trophic factor acting via the Akt kinase pathway. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2001:261-72. [PMID: 11205145 DOI: 10.1007/978-3-7091-6301-6_17] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Insulin-like growth factor-I (IGF-I) is a pleiotropic polypeptide with a wide range of actions in both central and peripheral nervous sytems. Over the past few years, we studied the trophic as well as neuromodulatory roles of IGF-I in the brain. Accumulated evidence indicates that IGF-I, apart from regulating growth and development, protects neurons against cell death induced by amyloidogenic derivatives, glucose or serum deprivation via the activation of intracellular pathways implicating phosphatidylinositide 3/Akt kinase, winged-helix family of transcription factor FKHRL1 phosphorylation or production of free radicals. The effects of IGF-I on neuroprotection, glucose metabolism and activity-dependent plasticity suggest the potential usefulness of this growth factor or related mimetics in the treatment of Alzheimer's disease and other neurodegenerative disorders.
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Affiliation(s)
- W H Zheng
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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12
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Doré S, Bastianetto S, Kar S, Quirion R. Protective and rescuing abilities of IGF-I and some putative free radical scavengers against beta-amyloid-inducing toxicity in neurons. Ann N Y Acad Sci 2000; 890:356-64. [PMID: 10668442 DOI: 10.1111/j.1749-6632.1999.tb08015.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
beta-Amyloid (A beta) peptides are most likely involved in the neurodegenerative process occurring in Alzheimer's Disease (AD) and are enriched in senile plaques. The mechanisms of A beta toxicity are not clear but likely involve free radicals and apoptosis. Much interest is currently aiming at developing effective approaches to block A beta toxicity in order to slow down disease progression. In that context, we are particularly interested in studying the role of insulin-like growth factors, particularly IGF-I and purported free radical scavengers including a Gingko biloba extract (EGb761) as blocker of A beta toxicity in a simple in vitro model of hippocampal primary cultures. We observed that both IGF-I and EGb761 are unique in that they are able not only to protect but even to rescue neurons against A beta toxicity. These results are summarized here and possible mechanisms of action are discussed to explain the protective properties of these two classes of agents.
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Affiliation(s)
- S Doré
- Douglas Hospital Research Center, McGill University, Montreal, Quebec, Canada
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Doré S, Kar S, Zheng WH, Quirion R. Rediscovering good old friend IGF-I in the new millenium: possible usefulness in Alzheimer's disease and stroke. PHARMACEUTICA ACTA HELVETIAE 2000; 74:273-80. [PMID: 10812969 DOI: 10.1016/s0031-6865(99)00037-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Much research has been done over the past two decades on the role of insulin-like growth factors I and II (IGF) in the maintenance of normal body homeostasis, especially in regard to various endocrine functions, growth and aging. For example, IGF-I is a well established promoter of tissue growth and has been used in the clinics for the treatment of growth related disorders, even being abused by athletes to enhance performance in competitions. In contrast, comparatively limited attention has been given to the potential significance of the IGFs in the central nervous system. Over the past few years, we have studied the trophic as well as neuromodulatory roles of the IGFs in the brain. IGF-I and IGF-II are potent modulators of acetylcholine release, IGF-I inhibiting release while IGF-II is a potent stimulant. Moreover, only the internalization of the IGF-I receptor complex was blocked by an inhibitor of phosphotyrosylation. This is in accordance with the differential nature of the IGF-I and IGF-II receptors, the former being a tyrosine kinase receptor while the later is a single transmembrane domain protein bearing binding sites for 6-mannose phosphate containing residues. The activation of IGF-I receptors protected neurons against cell death induced by amyloidogenic derivatives likely by an intracellular mechanism distinct from those involved in the regulation of acetylcholine release and neuronal growth. The stimulation of IGF-I receptors can activate intracellular pathways implicating a PI3/Akt kinase and CREB phosphorylation or modulate the production of free radicals. The effects, particularly those of IGF-I on key markers of the Alzheimer's (AD) brains namely cholinergic dysfunction, neuronal amyloid toxicity, tau phosphorylation and glucose metabolism suggest the potential usefulness of this growth factor in the treatment of neurodegenerative diseases. However, the poor bioavailability, enzymatic stability and brain penetration of IGF-I hamper progress in this regard. The recent development of a small, non-peptidyl mimetic of insulin able to directly activate the insulin receptor [Zhang, B., Salituro, G., Szalkowski, D., Li, Z., Zhang, Y., Royo, I., Vilella, D., Diez, M.T., Pelaez, F., Ruby, C., Kendall, R.L., Mao, X., Griffin, P., Calaycay, J., Zierath, J.R., Heck, J. V., Smith, R.G., Moller, D.E., 1999. Science, 284, 974-977] suggests that a similar strategy could be used for IGF-I and the IGF-I receptor leading to the characterization of IGF-I mimics of potential clinical usefulness.
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Affiliation(s)
- S Doré
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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14
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Sawa A, Khan AA, Hester LD, Snyder SH. Glyceraldehyde-3-phosphate dehydrogenase: nuclear translocation participates in neuronal and nonneuronal cell death. Proc Natl Acad Sci U S A 1997; 94:11669-74. [PMID: 9326668 PMCID: PMC23578 DOI: 10.1073/pnas.94.21.11669] [Citation(s) in RCA: 243] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/1997] [Indexed: 02/05/2023] Open
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein levels increase in particulate fractions in association with cell death in HEK293 cells, S49 cells, primary thymocytes, PC12 cells, and primary cerebral cortical neuronal cultures. Subcellular fractionation and immunocytochemistry reveal that this increase primarily reflects nuclear translocation. Nuclear GAPDH is tightly bound, resisting extraction by DNase or salt treatment. Treating primary thymocytes, PC12 cells, and primary cortical neurons with antisense but not sense oligonucleotides to GAPDH prevents cell death. Because cell-death-associated nuclear translocation of GAPDH and antisense protection occur in multiple neuronal and nonneuronal systems, we propose that GAPDH is a general mediator of cell death and uses nuclear translocation as a signaling mechanism.
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Affiliation(s)
- A Sawa
- Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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15
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Doré S, Kar S, Rowe W, Quirion R. Distribution and levels of [125I]IGF-I, [125I]IGF-II and [125I]insulin receptor binding sites in the hippocampus of aged memory-unimpaired and -impaired rats. Neuroscience 1997; 80:1033-40. [PMID: 9284058 DOI: 10.1016/s0306-4522(97)00154-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The insulin-like growth factors (IGF-I and IGF-II) and insulin are localized within distinct brain regions and their respective functions are mediated by specific membrane receptors. High densities of binding sites for these growth factors are discretely and differentially distributed throughout the brain, with prominent levels localized to the hippocampal formation. IGFs and insulin, in addition to their growth promoting actions, are considered to play important roles in the development and maintenance of normal cell functions throughout life. We compared the anatomical distribution and levels of IGF and insulin receptors in young (five month) and aged (25 month) memory-impaired and memory-unimpaired male Long Evans rats as determined in the Morris water maze task in order to determine if alterations in IGF and insulin activity may be related to the emergence of cognitive deficits in the aged memory-impaired rat. In the hippocampus, [125I]IGF-I receptors are concentrated primarily in the dentate gyrus (DG) and the CA3 sub-field while high amounts of [125I]IGF-II binding sites are localized to the pyramidal cell layer, and the granular cell layer of the DG. [125I]insulin binding sites are mostly found in the molecular layer of the DG and the CA1 sub-field. No significant differences were found in [125I]IGF-I. [125I]IGF-II or [125I]insulin binding levels in any regions or laminae of the hippocampus of young vs aged rats. and deficits in cognitive performance did not relate to altered levels of these receptors in aged memory-impaired vs aged memory-unimpaired rats. Other regions. including various cortical areas, were also examined and failed to reveal any significant differences between the three groups studied. It thus appears that IGF-I, IGF-II and insulin receptor sites are not markedly altered during the normal ageing process in the Long Evans rat, in spite of significant learning deficits in a sub-group (memory-impaired) of aged animals. Hence. recently reported changes in IGF-I receptor messenger RNA levels in aged memory-impaired rats are apparently not reflected at the level of the translated protein.
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Affiliation(s)
- S Doré
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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Kar S, Seto D, Doré S, Chabot JG, Quirion R. Systemic administration of kainic acid induces selective time dependent decrease in [125I]insulin-like growth factor I, [125I]insulin-like growth factor II and [125I]insulin receptor binding sites in adult rat hippocampal formation. Neuroscience 1997; 80:1041-55. [PMID: 9284059 DOI: 10.1016/s0306-4522(97)00185-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Administration of kainic acid evokes acute seizure in hippocampal pathways that results in a complex sequence of functional and structural alterations resembling human temporal lobe epilepsy. The structural alterations induced by kainic acid include selective loss of neurones in CA1-CA3 subfields and the hilar region of the dentate gyrus followed by sprouting and permanent reorganization of the synaptic connections of the mossy fibre pathways. Although the neuronal degeneration and process of reactive synaptogenesis have been extensively studied, at present little is known about means to prevent pathological conditions leading to kainate-induced cell death. In the present study, to address the role of insulin-like growth factors I and II, and insulin in neuronal survival as well as synaptic reorganization following kainate-induced seizure, the time course alterations of the corresponding receptors were evaluated. Additionally, using histological preparations, the temporal profile of neuronal degeneration and hypertrophy of resident astroglial cells were also studied. [125I]Insulin-like growth factor I binding was found to be decreased transiently in almost all regions of the hippocampal formation at 12 h following treatment with kainic acid. The dentate hilar region however, exhibited protracted decreases in [125I]insulin-like growth factor I receptor sites throughout (i.e. 30 days) the study. [125I]Insulin-like growth factor II receptor binding sites in the hippocampal formation were found to be differentially altered following systemic administration of kainic acid. A significant decrease in [125I]insulin-like growth factor II receptor sites was observed in CA1 subfield and the pyramidal cell layer of the Ammon's horn at all time points studied whereas the hilar region and the stratum radiatum did not exhibit alteration at any time. A kainate-induced decrease in [125I]insulin receptor binding was noted at all time points in the molecular layer of the dentate gyrus whereas binding in CA1-CA3 subfields and discrete layers of the Ammon's horn was found to be affected only after 12 h of treatment. These results, when analysed with reference to the observed histological changes and established neurotrophic/protective roles of insulin-like growth factors and insulin, suggest possible involvement of these growth factors in the cascade of neurotrophic events that is associated with the reorganization of the hippocampal formation observed following kainate-induced seizures.
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MESH Headings
- Animals
- Autoradiography
- Binding Sites
- Cell Survival
- Dentate Gyrus/metabolism
- Dentate Gyrus/pathology
- Down-Regulation
- Epilepsy, Temporal Lobe/chemically induced
- Epilepsy, Temporal Lobe/metabolism
- Epilepsy, Temporal Lobe/pathology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Hippocampus/pathology
- Humans
- Insulin/analogs & derivatives
- Insulin/metabolism
- Insulin-Like Growth Factor I/metabolism
- Insulin-Like Growth Factor II/metabolism
- Iodine Radioisotopes
- Kainic Acid/toxicity
- Male
- Nerve Degeneration
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Pyramidal Cells/drug effects
- Pyramidal Cells/metabolism
- Pyramidal Cells/pathology
- Rats
- Rats, Sprague-Dawley
- Receptor, IGF Type 1/analysis
- Receptor, IGF Type 1/biosynthesis
- Receptor, IGF Type 2/analysis
- Receptor, IGF Type 2/biosynthesis
- Receptor, Insulin/analysis
- Receptor, Insulin/biosynthesis
- Time Factors
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Affiliation(s)
- S Kar
- Douglas Hospital Research Center, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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