1
|
Wells AC, Mojica C, Lotfipour S. Hypersensitivity of the nicotinic acetylcholine receptor subunit (CHRNA2 L9'S/L9'S) in female adolescent mice produces deficits in nicotine-induced facilitation of hippocampal-dependent learning and memory. Neurobiol Learn Mem 2024; 213:107959. [PMID: 38964600 DOI: 10.1016/j.nlm.2024.107959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/24/2024] [Accepted: 07/01/2024] [Indexed: 07/06/2024]
Abstract
Adolescence is characterized by a critical period of maturation and growth, during which regions of the brain are vulnerable to long-lasting cognitive disturbances. Adolescent exposure to nicotine can lead to deleterious neurological and psychological outcomes. Moreover, the nicotinic acetylcholine receptor (nAChR) has been shown to play a functionally distinct role in the development of the adolescent brain. CHRNA2 encodes for the α2 subunit of nicotinic acetylcholine receptors associated with CA1 oriens lacunosum moleculare GABAergic interneurons and is associated with learning and memory. Previously, we found that adolescent male hypersensitive CHRNA2L9'S/L9' mice had impairments in learning and memory during a pre-exposure-dependent contextual fear conditioning task that could be rescued by low-dose nicotine exposure. In this study, we assessed learning and memory in female adolescent hypersensitive CHRNA2L9'S/L9' mice exposed to saline or a subthreshold dose of nicotine using a hippocampus-dependent task of pre-exposure-dependent contextual fear conditioning. We found that nicotine-treated wild-type female mice had significantly greater improvements in learning and memory than both saline-treated wild-type mice and nicotine-treated CHRNA2L9'S/L9' female mice. Thus, hyperexcitability of CHRNA2 in female adolescent mice ablated the nicotine-mediated potentiation of learning and memory seen in wild-types. Our results indicate that nicotine exposure during adolescence mediates sexually dimorphic patterns of learning and memory, with wild-type female adolescents being more susceptible to the effects of sub-threshold nicotine exposure. To understand the mechanism underlying sexually dimorphic behavior between hyperexcitable CHRNA2 mice, it is critical that further research be conducted.
Collapse
Affiliation(s)
- Alicia C Wells
- School of Medicine, University of California, Irvine, CA 92697, USA.
| | - Celina Mojica
- Graduate Division, University of California, Irvine, CA 92697, USA
| | - Shahrdad Lotfipour
- School of Medicine, University of California, Irvine, CA 92697, USA; Department of Emergency Medicine, Pharmaceutical Sciences, Pathology and Laboratory Medicine, University of California, Irvine, CA 92697, USA
| |
Collapse
|
2
|
Balleste AF, Sangadi A, Titus DJ, Johnstone T, Hogenkamp D, Gee KW, Atkins CM. Enhancing cognitive recovery in chronic traumatic brain injury through simultaneous allosteric modulation of α7 nicotinic acetylcholine and α5 GABA A receptors. Exp Neurol 2024; 379:114879. [PMID: 38942266 PMCID: PMC11283977 DOI: 10.1016/j.expneurol.2024.114879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/20/2024] [Accepted: 06/25/2024] [Indexed: 06/30/2024]
Abstract
Traumatic brain injury (TBI) leads to changes in the neural circuitry of the hippocampus that result in chronic learning and memory deficits. However, effective therapeutic strategies to ameliorate these chronic learning and memory impairments after TBI are limited. Two pharmacological targets for enhancing cognition are nicotinic acetylcholine receptors (nAChRs) and GABAA receptors (GABAARs), both of which regulate hippocampal network activity to form declarative memories. A promising compound, 522-054, both allosterically enhances α7 nAChRs and inhibits α5 subunit-containing GABAARs. Administration of 522-054 enhances long-term potentiation (LTP) and cognitive functioning in non-injured animals. In this study, we assessed the effects of 522-054 on hippocampal synaptic plasticity and learning and memory deficits in the chronic post-TBI recovery period. Adult male Sprague Dawley rats received moderate parasagittal fluid-percussion brain injury or sham surgery. At 12 wk after injury, we assessed basal synaptic transmission and LTP at the Schaffer collateral-CA1 synapse of the hippocampus. Bath application of 522-054 to hippocampal slices reduced deficits in basal synaptic transmission and recovered TBI-induced impairments in LTP. Moreover, treatment of animals with 522-054 at 12 wk post-TBI improved cue and contextual fear memory and water maze acquisition and retention without a measurable effect on cortical or hippocampal atrophy. These results suggest that dual allosteric modulation of α7 nAChR and α5 GABAAR signaling may be a potential therapy for treating cognitive deficits during chronic recovery from TBI.
Collapse
Affiliation(s)
- Alyssa F Balleste
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Akhila Sangadi
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - David J Titus
- Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis, MN, USA
| | | | - Derk Hogenkamp
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, USA
| | - Kelvin W Gee
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, USA
| | - Coleen M Atkins
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.
| |
Collapse
|
3
|
Li WW, Shi XY, Wei T, Guo TZ, Kingery WS, Clark JD. Alpha-7 Nicotinic Acetylcholine Receptor Activation Inhibits Trauma Induced Pronociceptive Autoimmune Responses. THE JOURNAL OF PAIN 2024; 25:104422. [PMID: 37951284 PMCID: PMC11058031 DOI: 10.1016/j.jpain.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/26/2023] [Accepted: 11/06/2023] [Indexed: 11/13/2023]
Abstract
Both autonomic nervous system dysfunction and immune system activation are characteristic of chronic pain after limb injuries. Cholinergic agonists reduce immune system activation in many settings. We hypothesized, therefore, that alpha-7 nicotinic acetylcholine receptor (α7nAChR) agonist administration would reduce nociceptive and immune changes after tibia fracture and cast immobilization in mice. Fracture mice were treated with either vehicle, a low (.2 mg/kg) dose, or a high (1 mg/kg) dose of the selective α7nAChR agonist PNU-282987 for 4 weeks. We assessed hindpaw allodynia and weight bearing as behavioral outcomes. The assessment of adaptive immune responses included regional lymph node hypertrophy, germinal center formation, α7nAChR expression, and IgM deposition. Assessment of innate immune system activation focused on IL-1β and IL-6 generation in fractured hindlimb skin. We observed that mechanical allodynia and unweighting were alleviated by PNU-282987 treatment. Drug treatment also reduced popliteal lymph node hypertrophy and germinal center formation. Immunohistochemical studies localized α7nAChR to germinal center B lymphocytes, and this expression increased after fracture. Analysis of fracture limb hindpaw skin demonstrated increased inflammatory mediator (IL-1β and IL-6) levels and IgM deposition, which were abrogated by PNU-282987. Serum analyses demonstrated fracture-induced IgM reactivity against keratin 16, histone 3.2, GFAP, and NMDAR-2B. Administration of PNU-282987 reduced the enhancement of IgM reactivity. Collectively, these data suggest that the α7nAChR is involved in regulating posttraumatic innate and adaptive immune responses and the associated nociceptive sensitization. PERSPECTIVE: These studies evaluate the effects of a selective α7nAChR agonist in a tibial fracture/cast immobilization model of limb pain. Administration of the drug reduced nociceptive and functional changes 4 weeks after injury. These novel findings suggest that well-tolerated α7nAChR agonists may be viable analgesics for chronic pain after limb injuries.
Collapse
Affiliation(s)
- Wen-wu Li
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, 94305, USA
| | - Xiao-you Shi
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, 94305, USA
| | - Tzuping Wei
- Palo Alto Veterans Institute for Research, 3801 Miranda Ave, Palo Alto, CA, 94304, USA
| | - Tian-Zhi Guo
- Palo Alto Veterans Institute for Research, 3801 Miranda Ave, Palo Alto, CA, 94304, USA
| | - Wade S Kingery
- Palo Alto Veterans Institute for Research, 3801 Miranda Ave, Palo Alto, CA, 94304, USA
| | - J. David Clark
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, 94305, USA
- Anesthesiology Service Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave, Palo Alto, CA, 94304, USA
| |
Collapse
|
4
|
Hussain G, Akram R, Anwar H, Sajid F, Iman T, Han HS, Raza C, De Aguilar JLG. Adult neurogenesis: a real hope or a delusion? Neural Regen Res 2024; 19:6-15. [PMID: 37488837 PMCID: PMC10479850 DOI: 10.4103/1673-5374.375317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/27/2023] [Accepted: 04/10/2023] [Indexed: 07/26/2023] Open
Abstract
Adult neurogenesis, the process of creating new neurons, involves the coordinated division, migration, and differentiation of neural stem cells. This process is restricted to neurogenic niches located in two distinct areas of the brain: the subgranular zone of the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle, where new neurons are generated and then migrate to the olfactory bulb. Neurogenesis has been thought to occur only during the embryonic and early postnatal stages and to decline with age due to a continuous depletion of neural stem cells. Interestingly, recent years have seen tremendous progress in our understanding of adult brain neurogenesis, bridging the knowledge gap between embryonic and adult neurogenesis. Here, we discuss the current status of adult brain neurogenesis in light of what we know about neural stem cells. In this notion, we talk about the importance of intracellular signaling molecules in mobilizing endogenous neural stem cell proliferation. Based on the current understanding, we can declare that these molecules play a role in targeting neurogenesis in the mature brain. However, to achieve this goal, we need to avoid the undesired proliferation of neural stem cells by controlling the necessary checkpoints, which can lead to tumorigenesis and prove to be a curse instead of a blessing or hope.
Collapse
Affiliation(s)
- Ghulam Hussain
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Rabia Akram
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Haseeb Anwar
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Faiqa Sajid
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Tehreem Iman
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Hyung Soo Han
- Department of Physiology, School of Medicine, Clinical Omics Institute, Kyungpook National University, Daegu, Korea
| | - Chand Raza
- Department of Zoology, Faculty of Chemistry and Life Sciences, Government College University, Lahore, Pakistan
| | - Jose-Luis Gonzalez De Aguilar
- INSERM, U1118, Mécanismes Centraux et Péripheriques de la Neurodégénérescence, Strasbourg, France, Université de Strasbourg, Strasbourg, France
| |
Collapse
|
5
|
Rezayof A, Ghasemzadeh Z, Sahafi OH. Addictive drugs modify neurogenesis, synaptogenesis and synaptic plasticity to impair memory formation through neurotransmitter imbalances and signaling dysfunction. Neurochem Int 2023; 169:105572. [PMID: 37423274 DOI: 10.1016/j.neuint.2023.105572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 07/11/2023]
Abstract
Drug abuse changes neurophysiological functions at multiple cellular and molecular levels in the addicted brain. Well-supported scientific evidence suggests that drugs negatively affect memory formation, decision-making and inhibition, and emotional and cognitive behaviors. The mesocorticolimbic brain regions are involved in reward-related learning and habitual drug-seeking/taking behaviors to develop physiological and psychological dependence on the drugs. This review highlights the importance of specific drug-induced chemical imbalances resulting in memory impairment through various neurotransmitter receptor-mediated signaling pathways. The mesocorticolimbic modifications in the expression levels of brain-derived neurotrophic factor (BDNF) and the cAMP-response element binding protein (CREB) impair reward-related memory formation following drug abuse. The contributions of protein kinases and microRNAs (miRNAs), along with the transcriptional and epigenetic regulation have also been considered in memory impairment underlying drug addiction. Overall, we integrate the research on various types of drug-induced memory impairment in distinguished brain regions and provide a comprehensive review with clinical implications addressing the upcoming studies.
Collapse
Affiliation(s)
- Ameneh Rezayof
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Zahra Ghasemzadeh
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Oveis Hosseinzadeh Sahafi
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| |
Collapse
|
6
|
Letsinger AC, Nacer SA, Stevanovic KD, Larson GJ, DeFilipp JS, Cushman JD, Yakel JL. Genetic deletion of α7 nAChRs reduces hippocampal granule and pyramidal cell number in both sexes but impairs pattern separation in males only. Front Neurosci 2023; 17:1244118. [PMID: 37746145 PMCID: PMC10513752 DOI: 10.3389/fnins.2023.1244118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/22/2023] [Indexed: 09/26/2023] Open
Abstract
Introduction Neurogenesis within the dentate gyrus is thought to play an important role in cognitive processes such as reversal learning and pattern separation. The α7 nicotinic acetylcholine receptor (α7 nAChR) is expressed early in newly formed granule cells of the dentate gyrus, though its role in neurogenesis and related cognitive function is not fully understood. Methods To better characterize relevant function of α7 nAChRs, we performed unbiased stereology to quantify hippocampal granule cells, pyramidal cells, and total volume and used a touchscreen operant spatial discrimination/reversal task to test pattern separation in a global α7 nAChR knockout mouse line. Results The knockout resulted in an ≈22% reduction in granule cells and a ≈ 20% reduction in pyramidal cells in both sexes, with no change in total hippocampal volume. However, the knockout impaired performance in the touchscreen task for males only. The sex-dependent difference in behavioral, but not stereological, results suggest a divergence in the structure-function relationship in males versus females. Detailed analyses revealed males were more biased by the initial reversal contingency relative to females indicating a potential source of the sex-specific interaction with the loss of α7 nAChRs. Discussion These findings argue that the α7 nAChR plays a critical role in hippocampal development, not just granule cell neurogenesis, and plays a sex-dependent role in cognitive function.
Collapse
Affiliation(s)
- Ayland C. Letsinger
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| | - Samir A. Nacer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| | - Korey D. Stevanovic
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| | - Gary J. Larson
- Social & Scientific Systems, Inc., a DLH Holdings Corp. Company, Durham, NC, United States
| | - Jemma S. DeFilipp
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| | - Jesse D. Cushman
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| | - Jerrel L. Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| |
Collapse
|
7
|
Echeverria V, Mendoza C, Iarkov A. Nicotinic acetylcholine receptors and learning and memory deficits in Neuroinflammatory diseases. Front Neurosci 2023; 17:1179611. [PMID: 37255751 PMCID: PMC10225599 DOI: 10.3389/fnins.2023.1179611] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 04/07/2023] [Indexed: 06/01/2023] Open
Abstract
Animal survival depends on cognitive abilities such as learning and memory to adapt to environmental changes. Memory functions require an enhanced activity and connectivity of a particular arrangement of engram neurons, supported by the concerted action of neurons, glia, and vascular cells. The deterioration of the cholinergic system is a common occurrence in neurological conditions exacerbated by aging such as traumatic brain injury (TBI), posttraumatic stress disorder (PTSD), Alzheimer's disease (AD), and Parkinson's disease (PD). Cotinine is a cholinergic modulator with neuroprotective, antidepressant, anti-inflammatory, antioxidant, and memory-enhancing effects. Current evidence suggests Cotinine's beneficial effects on cognition results from the positive modulation of the α7-nicotinic acetylcholine receptors (nAChRs) and the inhibition of the toll-like receptors (TLRs). The α7nAChR affects brain functions by modulating the function of neurons, glia, endothelial, immune, and dendritic cells and regulates inhibitory and excitatory neurotransmission throughout the GABA interneurons. In addition, Cotinine acting on the α7 nAChRs and TLR reduces neuroinflammation by inhibiting the release of pro-inflammatory cytokines by the immune cells. Also, α7nAChRs stimulate signaling pathways supporting structural, biochemical, electrochemical, and cellular changes in the Central nervous system during the cognitive processes, including Neurogenesis. Here, the mechanisms of memory formation as well as potential mechanisms of action of Cotinine on memory preservation in aging and neurological diseases are discussed.
Collapse
Affiliation(s)
- Valentina Echeverria
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Concepción, Chile
- Research and Development Department, Bay Pines VAHCS, Bay Pines, FL, United States
| | - Cristhian Mendoza
- Facultad de Odontologia y Ciencias de la Rehabilitacion, Universidad San Sebastián, Concepción, Chile
| | - Alex Iarkov
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Concepción, Chile
| |
Collapse
|
8
|
Kubo S, Hirano T, Miyata Y, Ohno S, Onaru K, Ikenaka Y, Nakayama SM, Ishizuka M, Mantani Y, Yokoyama T, Hoshi N. Sex-specific behavioral effects of acute exposure to the neonicotinoid clothianidin in mice. Toxicol Appl Pharmacol 2022; 456:116283. [DOI: 10.1016/j.taap.2022.116283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/02/2022] [Accepted: 10/11/2022] [Indexed: 11/18/2022]
|
9
|
Zhou YQ, Liu DQ, Liu C, Xu AJ, Tian YK, Mei W, Tian XB. Targeting α7 nicotinic acetylcholine receptors for chronic pain. Front Mol Neurosci 2022; 15:970040. [PMID: 36245927 PMCID: PMC9561890 DOI: 10.3389/fnmol.2022.970040] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Despite rapid advances in the field of chronic pain, it remains extremely challenging in the clinic. Pain treatment strategies have not improved for decades as opioids remain the main prescribed drugs for chronic pain management. However, long-term use of opioids often leads to detrimental side effects. Therefore, uncovering the mechanisms underlying the development and maintenance of chronic pain may aid the discovery of novel therapeutics to benefit patients with chronic pain. Substantial evidence indicates downregulation of α7 nicotinic acetylcholine receptors (α7 nAChR) in the sciatic nerve, dorsal root ganglia, and spinal cord dorsal horn in rodent models of chronic pain. Moreover, our recent study and results from other laboratories demonstrate that potentiation of α7 nAChR attenuates pain behaviors in various murine models of chronic pain. This review summarized and discussed the preclinical evidence demonstrating the therapeutic potential of α7 nAChR agonists and allosteric modulators in chronic pain. This evidence indicates that potentiation of α7 nAChR is beneficial in chronic pain, mostly by alleviating neuroinflammation. Overall, α7 nAChR-based therapy for chronic pain is an area with great promise, but more research regarding its detailed mechanisms is warranted.
Collapse
|
10
|
The Alpha 7 Nicotinic Acetylcholine Receptor Does Not Affect Neonatal Brain Injury. Biomedicines 2022; 10:biomedicines10082023. [PMID: 36009570 PMCID: PMC9405910 DOI: 10.3390/biomedicines10082023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 11/16/2022] Open
Abstract
Inflammation plays a central role in the development of neonatal brain injury. The alpha 7 nicotinic acetylcholine receptor (α7nAChR) can modulate inflammation and has shown promising results as a treatment target in rodent models of adult brain injury. However, little is known about the role of the α7nAChR in neonatal brain injury. Hypoxic-ischemic (HI) brain injury was induced in male and female C57BL/6 mice, α7nAChR knock-out (KO) mice and their littermate controls on postnatal day (PND) 9–10. C57BL/6 pups received i.p. injections of α7nAChR agonist PHA 568487 (8 mg/kg) or saline once daily, with the first dose given directly after HI. Caspase-3 activity and cytokine mRNA expression in the brain was analyzed 24 h after HI. Motor function was assessed 24 and 48 h after HI, and immunohistochemistry was used to assess tissue loss at 24 h and 7 days after HI and microglial activation 7 days after HI. Activation of α7nAChR with the agonist PHA 568487 significantly decreased CCL2/MCP-1, CCL5/RANTES and IL-6 gene expression in the injured brain hemisphere 24 h after HI compared with saline controls in male, but not female, pups. However, α7nAChR activation did not alter caspase-3 activity and TNFα, IL-1β and CD68 mRNA expression. Furthermore, agonist treatment did not affect motor function (24 or 48 h), neuronal tissue loss (24 h or 7 days) or microglia activation (7 days) after HI in either sex. Knock-out of α7nAChR did not influence neuronal tissue loss 7 days after HI. In conclusion, targeting the α7nAChR in neonatal brain injury shows some effect on dampening acute inflammatory responses in male pups. However, this does not lead to an effect on overall injury outcome.
Collapse
|
11
|
Li Y, Ji M, Yang J. Current Understanding of Long-Term Cognitive Impairment After Sepsis. Front Immunol 2022; 13:855006. [PMID: 35603184 PMCID: PMC9120941 DOI: 10.3389/fimmu.2022.855006] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
Sepsis is recognized as a life-threatening multi-organ dysfunction resulting from a dysregulated host response to infection. Although the incidence and mortality of sepsis decrease significantly due to timely implementation of anti-infective and support therapies, accumulating evidence suggests that a great proportion of survivors suffer from long-term cognitive impairment after hospital discharge, leading to decreased life quality and substantial caregiving burdens for family members. Several mechanisms have been proposed for long-term cognitive impairment after sepsis, which are not mutually exclusive, including blood-brain barrier disruption, neuroinflammation, neurotransmitter dysfunction, and neuronal loss. Targeting these critical processes might be effective in preventing and treating long-term cognitive impairment. However, future in-depth studies are required to facilitate preventive and/or treatment strategies for long-term cognitive impairment after sepsis.
Collapse
Affiliation(s)
- Ying Li
- Department of Anesthesiology, Jiangyin Hospital, Affiliated to Southeast University Medical School, Jiangyin, China
| | - Muhuo Ji
- Department of Anesthesiology, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
| | - Jianjun Yang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| |
Collapse
|
12
|
Jennen L, Mazereel V, Lecei A, Samaey C, Vancampfort D, van Winkel R. Exercise to spot the differences: a framework for the effect of exercise on hippocampal pattern separation in humans. Rev Neurosci 2022; 33:555-582. [PMID: 35172422 DOI: 10.1515/revneuro-2021-0156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 12/12/2022]
Abstract
Exercise has a beneficial effect on mental health and cognitive functioning, but the exact underlying mechanisms remain largely unknown. In this review, we focus on the effect of exercise on hippocampal pattern separation, which is a key component of episodic memory. Research has associated exercise with improvements in pattern separation. We propose an integrated framework mechanistically explaining this relationship. The framework is divided into three pathways, describing the pro-neuroplastic, anti-inflammatory and hormonal effects of exercise. The pathways are heavily intertwined and may result in functional and structural changes in the hippocampus. These changes can ultimately affect pattern separation through direct and indirect connections. The proposed framework might guide future research on the effect of exercise on pattern separation in the hippocampus.
Collapse
Affiliation(s)
- Lise Jennen
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Victor Mazereel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
| | - Aleksandra Lecei
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Celine Samaey
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Davy Vancampfort
- University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium.,KU Leuven Department of Rehabilitation Sciences, ON IV Herestraat 49, bus 1510, 3000, Leuven, Belgium
| | - Ruud van Winkel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
| |
Collapse
|
13
|
Guo N, McDermott KD, Shih YT, Zanga H, Ghosh D, Herber C, Meara WR, Coleman J, Zagouras A, Wong LP, Sadreyev R, Gonçalves JT, Sahay A. Transcriptional regulation of neural stem cell expansion in the adult hippocampus. eLife 2022; 11:e72195. [PMID: 34982030 PMCID: PMC8820733 DOI: 10.7554/elife.72195] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 01/03/2022] [Indexed: 12/11/2022] Open
Abstract
Experience governs neurogenesis from radial-glial neural stem cells (RGLs) in the adult hippocampus to support memory. Transcription factors (TFs) in RGLs integrate physiological signals to dictate self-renewal division mode. Whereas asymmetric RGL divisions drive neurogenesis during favorable conditions, symmetric divisions prevent premature neurogenesis while amplifying RGLs to anticipate future neurogenic demands. The identities of TFs regulating RGL symmetric self-renewal, unlike those that regulate RGL asymmetric self-renewal, are not known. Here, we show in mice that the TF Kruppel-like factor 9 (Klf9) is elevated in quiescent RGLs and inducible, deletion of Klf9 promotes RGL activation state. Clonal analysis and longitudinal intravital two-photon imaging directly demonstrate that Klf9 functions as a brake on RGL symmetric self-renewal. In vivo translational profiling of RGLs lacking Klf9 generated a molecular blueprint for RGL symmetric self-renewal that was characterized by upregulation of genetic programs underlying Notch and mitogen signaling, cell cycle, fatty acid oxidation, and lipogenesis. Together, these observations identify Klf9 as a transcriptional regulator of neural stem cell expansion in the adult hippocampus.
Collapse
Affiliation(s)
- Nannan Guo
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
- BROAD Institute of Harvard and MITCambridgeUnited States
| | - Kelsey D McDermott
- Ruth L. and David S. Gottesman Institute for Stem Cell Biology and Regenerative Medicine; Dominick Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Yu-Tzu Shih
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
- BROAD Institute of Harvard and MITCambridgeUnited States
| | - Haley Zanga
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
- BROAD Institute of Harvard and MITCambridgeUnited States
| | - Debolina Ghosh
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
| | - Charlotte Herber
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
| | - William R Meara
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
| | - James Coleman
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
| | - Alexia Zagouras
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
| | - Lai Ping Wong
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
| | - Ruslan Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
| | - J Tiago Gonçalves
- Ruth L. and David S. Gottesman Institute for Stem Cell Biology and Regenerative Medicine; Dominick Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
- BROAD Institute of Harvard and MITCambridgeUnited States
| |
Collapse
|
14
|
Reitz NL, Nunes PT, Savage LM. Adolescent Binge-Type Ethanol Exposure in Rats Mirrors Age-Related Cognitive Decline by Suppressing Cholinergic Tone and Hippocampal Neurogenesis. Front Behav Neurosci 2021; 15:772857. [PMID: 34744657 PMCID: PMC8569390 DOI: 10.3389/fnbeh.2021.772857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/28/2021] [Indexed: 11/15/2022] Open
Abstract
Heavy alcohol consumption followed by periods of abstinence (i.e., binge drinking) during adolescence is a concern for both acute and chronic health issues. Persistent brain damage after adolescent intermittent ethanol exposure in rodents, a model of binge drinking, includes reduced hippocampal neurogenesis and a loss of neurons in the basal forebrain that express the cholinergic phenotype. The circuit formed between those regions, the septohippocampal pathway, is critical for learning and memory. Furthermore, this circuit is also altered during the aging process. Thus, we examined whether pathology in septohippocampal circuit and impairments in spatial behaviors are amplified during aging following adolescent intermittent ethanol exposure. Female and male rats were exposed to intermittent intragastric gavage of water (control) or 20% ethanol (dose of 5 g/kg) for a 2 days on/off cycle from postnatal days 25-55. Either 2 (young adult) or 12-14 (middle-age) months post exposure, rats were tested on two spatial tasks: spontaneous alternation and novel object in place. Acetylcholine efflux was assessed in the hippocampus during both tasks. There was no adolescent ethanol-induced deficit on spontaneous alternation, but middle-aged male rats displayed lower alternation rates. Male rats exposed to ethanol during adolescence had blunted behavioral evoked acetylcholine during spontaneous alternation testing. All ethanol-exposed rats displayed suppression of the cholinergic neuronal phenotype. On the novel object in place task, regardless of sex, ethanol-exposed rats performed significantly worse than control-treated rats, and middle aged-rats, regardless of sex or ethanol exposure, were significantly impaired relative to young adult rats. These results indicate that male rats display earlier age-related cognitive impairment on a working memory task. Furthermore, male rats exposed to ethanol during adolescence have blunted behavior-evoked hippocampal acetylcholine efflux. In addition, middle-aged and ethanol-exposed rats, regardless of sex, are impaired at determining discrete spatial relationship between objects. This type of pattern separation impairment was associated with a loss of neurogenesis. Thus, binge-type adolescent ethanol exposure does affect the septohippocampal circuit, and can accelerate age-related cognitive impairment on select spatial tasks.
Collapse
Affiliation(s)
| | | | - Lisa M. Savage
- Department of Psychology, Binghamton University – State University of New York, Binghamton, NY, United States
| |
Collapse
|
15
|
Seyedaghamiri F, Mahmoudi J, Hosseini L, Sadigh-Eteghad S, Farhoudi M. Possible Engagement of Nicotinic Acetylcholine Receptors in Pathophysiology of Brain Ischemia-Induced Cognitive Impairment. J Mol Neurosci 2021; 72:642-652. [PMID: 34596872 DOI: 10.1007/s12031-021-01917-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/12/2021] [Indexed: 10/20/2022]
Abstract
Post-stroke disabilities like cognitive impairment impose are complex conditions with great economic burdens on health care systems. For these comorbidities, no effective therapies have been identified yet. Nicotinic acetylcholine receptors (nAChRs) are multifunctional receptors participating in various behavioral and neurobiological functions. During brain ischemia, the increased glutamate accumulation leads to neuronal excitotoxicity as well as mitochondrial dysfunction. These abnormalities then cause the increased levels of oxidants, which play key roles in neuronal death and apoptosis in the infarct zone. Additionally, recall of cytokines and inflammatory factors play a prominent role in the exacerbation of ischemic injury. As well, neurotrophic factors' insufficiency results in synaptic dysfunction and cognitive impairments in ischemic brain. Of note, nAChRs through various signaling pathways can participate in therapeutic approaches such as cholinergic system's stimulation, and reduction of excitotoxicity, inflammation, apoptosis, oxidative stress, mitochondrial dysfunction, and autophagy. Moreover, the possible roles of nAChRs in neurogenesis, synaptogenesis, and stimulation of neurotrophic factors expression have been reported previously. On the other hand, the majority of the above-mentioned mechanisms were found to be common in both brain ischemia pathogenesis and cognitive function tuning. Therefore, it seems that nAChRs might be known as key regulators in the control of ischemia pathology, and their modulation could be considered as a new avenue in the multi-target treatment of post-stroke cognitive impairment.
Collapse
Affiliation(s)
| | - Javad Mahmoudi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Leila Hosseini
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saeed Sadigh-Eteghad
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Mehdi Farhoudi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| |
Collapse
|
16
|
Soltani Zangbar H, Shahabi P, Seyedi Vafaee M, Ghadiri T, Ebrahimi Kalan A, Fallahi S, Ghorbani M, Jafarzadehgharehziaaddin M. Hippocampal neurodegeneration and rhythms mirror each other during acute spinal cord injury in male rats. Brain Res Bull 2021; 172:31-42. [PMID: 33848614 DOI: 10.1016/j.brainresbull.2021.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 03/20/2021] [Accepted: 04/07/2021] [Indexed: 12/29/2022]
Abstract
Spinal Cord Injury (SCI), triggers neurodegenerative changes in the spinal cord, and simultaneously alters oscillatory manifestations of motor cortex. However, these disturbances may not be limited to motor areas and other parts such as hippocampus, which is vital in the neurogenesis and cognitive function, may be affected in the neurogenic and oscillatory manners. Addressing this remarkable complication of SCI, we evaluated the hippocampal neurogenesis and rhythms through acute phase of SCI. In the present study, we used 40 male rats (Sham.W1 = 10, SCI.W1 = 10, Sham.W2 = 10, SCI.W2 = 10), and findings revealed that contusive SCI declines hippocampal rhythms (Delta, Theta, Beta, Gamma) power and max-frequency. Also, there was a significant decrease in the DCX + and BrdU + cells of the dentate gyrus; correlated significantly with rhythms power decline. Considering the TUNEL assay analysis, there were significantly greater apoptotic cells, in the CA1, CA3, and DG regions of injured animals. Furthermore, according to the western blotting analysis, the expression of receptors (NMDA, GABAA, Muscarinic1), which are essential in the neurogenesis and generation of rhythms significantly attenuated following SCI. Our study demonstrated that acute SCI, alters the power and max-frequency of hippocampal rhythms parallel with changes in the hippocampal neurogenesis, apoptosis, and receptors expression.
Collapse
Affiliation(s)
- Hamid Soltani Zangbar
- Department of Neuroscience and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Neurosciences Research Centre (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Parviz Shahabi
- Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Neurosciences Research Centre (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran; Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Manouchehr Seyedi Vafaee
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark; Department of Psychiatry, Odense University Hospital, Odense, Denmark
| | - Tahereh Ghadiri
- Department of Neuroscience and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Abbas Ebrahimi Kalan
- Department of Neuroscience and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Solmaz Fallahi
- Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Meysam Ghorbani
- Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | | |
Collapse
|
17
|
Madrid LI, Jimenez-Martin J, Coulson EJ, Jhaveri DJ. Cholinergic regulation of adult hippocampal neurogenesis and hippocampus-dependent functions. Int J Biochem Cell Biol 2021; 134:105969. [PMID: 33727042 DOI: 10.1016/j.biocel.2021.105969] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/10/2021] [Indexed: 10/21/2022]
Abstract
The production and circuit integration of new neurons is one of the defining features of the adult mammalian hippocampus. A wealth of evidence has established that adult hippocampal neurogenesis is exquisitely sensitive to neuronal activity-mediated regulation. How these signals are interpreted and contribute to neurogenesis and hippocampal functions has been a subject of immense interest. In particular, neurotransmitters, in addition to their synaptic roles, have been shown to offer important trophic support. Amongst these, acetylcholine, which has a prominent role in cognition, has been implicated in regulating neurogenesis. In this review, we appraise the evidence linking the contribution of cholinergic signalling to the regulation of adult hippocampal neurogenesis and hippocampus-dependent functions. We discuss open questions that need to be addressed to gain a deeper mechanistic understanding of the role and translational potential of acetylcholine and its receptors in regulating this form of cellular neuroplasticity.
Collapse
Affiliation(s)
- Lidia I Madrid
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Javier Jimenez-Martin
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Elizabeth J Coulson
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Dhanisha J Jhaveri
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; Mater Research Institute - The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia.
| |
Collapse
|
18
|
Gaidhani N, Tucci FC, Kem WR, Beaton G, Uteshev VV. Therapeutic efficacy of α7 ligands after acute ischaemic stroke is linked to conductive states of α7 nicotinic ACh receptors. Br J Pharmacol 2021; 178:1684-1704. [PMID: 33496352 DOI: 10.1111/bph.15392] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/22/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Targeting α7 nicotinic ACh receptors (nAChRs) in neuroinflammatory disorders including acute ischaemic stroke holds significant therapeutic promise. However, therapeutically relevant signalling mechanisms remain unidentified. Activation of neuronal α7 nAChRs triggers ionotropic signalling, but there is limited evidence for it in immunoglial tissues. The α7 ligands which are effective in reducing acute ischaemic stroke damage promote α7 ionotropic activity, suggesting a link between their therapeutic effects for treating acute ischaemic stroke and activation of α7 conductive states. EXPERIMENTAL APPROACH This hypothesis was tested using a transient middle cerebral artery occlusion (MCAO) model of acute ischaemic stroke, NS6740, a known selective non-ionotropic agonist of α7 nAChRs and 4OH-GTS-21, a partial α7 agonist. NS6740-like ligands exhibiting low efficacy/potency for ionotropic activity will be referred to as non-ionotropic agonists or "metagonists". KEY RESULTS 4OH-GTS-21, used as a positive control, significantly reduced neurological deficits and brain injury after MCAO as compared to vehicle and NS6740. By contrast, NS6740 was ineffective in identical assays and reversed the effects of 4OH-GTS-21 when these compounds were co-applied. Electrophysiological recordings from acute hippocampal slices obtained from NS6740-injected animals demonstrated its remarkable brain availability and protracted effects on α7 nAChRs as evidenced by sustained (>8 h) alterations in α7 ionotropic responsiveness. CONCLUSION AND IMPLICATIONS These results suggest that α7 ionotropic activity may be obligatory for therapeutic efficacy of α7 ligands after acute ischaemic stroke yet, highlight the potential for selective application of α7 ligands to disease states based on their mode of receptor activation.
Collapse
Affiliation(s)
- Nikhil Gaidhani
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Fabio C Tucci
- Epigen Biosciences, Inc., San Diego, California, USA
| | - William R Kem
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Graham Beaton
- Epigen Biosciences, Inc., San Diego, California, USA
| | - Victor V Uteshev
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| |
Collapse
|
19
|
Multiple Roles for Cholinergic Signaling from the Perspective of Stem Cell Function. Int J Mol Sci 2021; 22:ijms22020666. [PMID: 33440882 PMCID: PMC7827396 DOI: 10.3390/ijms22020666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 01/11/2023] Open
Abstract
Stem cells have extensive proliferative potential and the ability to differentiate into one or more mature cell types. The mechanisms by which stem cells accomplish self-renewal provide fundamental insight into the origin and design of multicellular organisms. These pathways allow the repair of damage and extend organismal life beyond that of component cells, and they probably preceded the evolution of complex metazoans. Understanding the true nature of stem cells can only come from discovering how they are regulated. The concept that stem cells are controlled by particular microenvironments, also known as niches, has been widely accepted. Technical advances now allow characterization of the zones that maintain and control stem cell activity in several organs, including the brain, skin, and gut. Cholinergic neurons release acetylcholine (ACh) that mediates chemical transmission via ACh receptors such as nicotinic and muscarinic receptors. Although the cholinergic system is composed of organized nerve cells, the system is also involved in mammalian non-neuronal cells, including stem cells, embryonic stem cells, epithelial cells, and endothelial cells. Thus, cholinergic signaling plays a pivotal role in controlling their behaviors. Studies regarding this signal are beginning to unify our understanding of stem cell regulation at the cellular and molecular levels, and they are expected to advance efforts to control stem cells therapeutically. The present article reviews recent findings about cholinergic signaling that is essential to control stem cell function in a cholinergic niche.
Collapse
|
20
|
Loss of α7 nicotinic acetylcholine receptors in GABAergic neurons causes sex-dependent decreases in radial glia-like cell quantity and impairments in cognitive and social behavior. Brain Struct Funct 2021; 226:365-379. [PMID: 33398432 DOI: 10.1007/s00429-020-02179-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 11/10/2020] [Indexed: 12/25/2022]
Abstract
The dentate gyrus (DG) is a unique brain structure in that neurons can be generated postnatally and integrated within existing circuitry throughout life. The maturation process of these newly generated neurons (granule cells) is modulated by nicotinic acetylcholine receptors (nAChRs) through a variety of mechanisms such as neural stem pool proliferation, cell survival, signal modulation, and dendritic integration. Disrupted nAChR signaling has been implicated in neuropsychiatric and neurodegenerative disorders, potentially via alterations in DG neurogenesis. GABAergic interneurons are known to express nAChRs, predominantly the α7 subtype, and have been shown to shape development, integration, and circuit reorganization of DG granule cells. Therefore, we examined histological and behavioral effects of knocking out α7 nAChRs in GABAergic neurons. Deletion of α7 nAChRs resulted in a reduction of radial glia-like cells within the subgranular zone of the DG and a concomitant trend towards decreased immature neurons, specifically in male mice, as well as sex-dependent changes in several behaviors, including social recognition and spatial learning. Overall, these findings suggest α7 nAChRs expressed in GABAergic neurons play an important role in regulating the adult neural stem cell pool and behavior in a sex-dependent manner. This provides important insight into the mechanisms by which cholinergic dysfunction contributes to the cognitive and behavioral changes associated with neurodevelopmental and neurodegenerative disorders.
Collapse
|
21
|
Nunes PT, Kipp BT, Reitz NL, Savage LM. Aging with alcohol-related brain damage: Critical brain circuits associated with cognitive dysfunction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2019; 148:101-168. [PMID: 31733663 PMCID: PMC7372724 DOI: 10.1016/bs.irn.2019.09.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alcoholism is associated with brain damage and impaired cognitive functioning. The relative contributions of different etiological factors, such as alcohol, thiamine deficiency and age vulnerability, to the development of alcohol-related neuropathology and cognitive impairment are still poorly understood. One reason for this quandary is that both alcohol toxicity and thiamine deficiency produce brain damage and cognitive problems that can be modulated by age at exposure, aging following alcohol toxicity or thiamine deficiency, and aging during chronic alcohol exposure. Pre-clinical models of alcohol-related brain damage (ARBD) have elucidated some of the contributions of ethanol toxicity and thiamine deficiency to neuroinflammation, neuronal loss and functional deficits. However, the critical variable of age at the time of exposure or long-term aging with ARBD has been relatively ignored. Acute thiamine deficiency created a massive increase in neuroimmune genes and proteins within the thalamus and significant increases within the hippocampus and frontal cortex. Chronic ethanol treatment throughout adulthood produced very minor fluctuations in neuroimmune genes, regardless of brain region. Intermittent "binge-type" ethanol during the adolescent period established an intermediate neuroinflammatory response in the hippocampus and frontal cortex, that can persist into adulthood. Chronic excessive drinking throughout adulthood, adolescent intermittent ethanol exposure, and thiamine deficiency all led to a loss of the cholinergic neuronal phenotype within the basal forebrain, reduced hippocampal neurogenesis, and alterations in the frontal cortex. Only thiamine deficiency results in gross pathological lesions of the thalamus. The behavioral impairment following these types of treatments is hierarchical: Thiamine deficiency produces the greatest impairment of hippocampal- and prefrontal-dependent behaviors, chronic ethanol drinking ensues mild impairments on both types of tasks and adolescent intermittent ethanol exposure leads to impairments on frontocortical tasks, with sparing on most hippocampal-dependent tasks. However, our preliminary data suggest that as rodents age following adolescent intermittent ethanol exposure, hippocampal functional deficits began to emerge. A necessary requirement for the advancement of understanding the neural consequences of alcoholism is a more comprehensive assessment and understanding of how excessive alcohol drinking at different development periods (adolescence, early adulthood, middle-aged and aged) influences the trajectory of the aging process, including pathological aging and disease.
Collapse
Affiliation(s)
- Polliana Toledo Nunes
- Developmental Exposure Alcohol Research Center, Behavioral Neuroscience Program, Department of Psychology, Binghamton University, State University of New York, Binghamton, NY, United States
| | - Brian T Kipp
- Developmental Exposure Alcohol Research Center, Behavioral Neuroscience Program, Department of Psychology, Binghamton University, State University of New York, Binghamton, NY, United States
| | - Nicole L Reitz
- Developmental Exposure Alcohol Research Center, Behavioral Neuroscience Program, Department of Psychology, Binghamton University, State University of New York, Binghamton, NY, United States
| | - Lisa M Savage
- Developmental Exposure Alcohol Research Center, Behavioral Neuroscience Program, Department of Psychology, Binghamton University, State University of New York, Binghamton, NY, United States.
| |
Collapse
|