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Patel RK, Pirozzi NT, Hoefler TG, Connolly MG, Singleton LG, Kohman RA. Sex-dependent deficits in associative learning across multiple LPS doses. Physiol Behav 2023; 268:114249. [PMID: 37210020 DOI: 10.1016/j.physbeh.2023.114249] [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: 04/10/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/22/2023]
Abstract
Activation of the immune system by administration of the bacterial endotoxin lipopolysaccharide (LPS) impairs cognitive and neural plasticity processes. For instance, acute LPS exposure has been reported to impair memory consolidation, spatial learning and memory, and associative learning. However, the inclusion of both males and females in basic research is limited. Whether LPS-induced cognitive deficits are comparable in males and females is currently unclear. Therefore, the present study evaluated sex differences in associative learning following administration of LPS at a dose (i.e., 0.25 mg/kg) that impairs learning in males and higher LPS doses (i.e., 0.325 - 1 mg/kg) across multiple experiments. Adult male and female C57BL/6J mice were trained in a two-way active avoidance conditioning task following their respective treatments. Results showed that LPS had sex-dependent effects on associative learning. The 0.25 mg/kg LPS dose impaired learning in males, consistent with prior work. However, LPS, at any of the doses employed across three experiments, did not disrupt associative learning in females. Female mice were resistant to learning deficits despite showing heightened levels of select proinflammatory cytokines in response to LPS. Collectively, these findings demonstrate that the learning impairments resulting from acute LPS exposure are sex-dependent.
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Affiliation(s)
- Reeva K Patel
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Nicolas T Pirozzi
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Tiffany G Hoefler
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Meghan G Connolly
- University of Illinois Urbana-Champaign, Department of Psychology, Champaign, IL, USA.
| | - Lauren G Singleton
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Rachel A Kohman
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
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2
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Sun J, Qiu L, Zhang H, Zhou Z, Ju L, Yang J. CRHR1 antagonist alleviates LPS-induced depression-like behaviour in mice. BMC Psychiatry 2023; 23:17. [PMID: 36624454 PMCID: PMC9830857 DOI: 10.1186/s12888-023-04519-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 01/02/2023] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Maladaptation of the HPA (hypothalamic-pituitary-adrenal) axis plays an important role in depression-like behaviour, but the specific molecular mechanisms are unknown. Here, we determined the roles of CRHR1 (corticotrophin releasing hormone receptor 1) and nectin3 in LPS (lipopolysaccharide)-induced depression-like behaviour in mice. METHODS C57BL/6 male mice were intraperitoneally injected with LPS (0.83 g/kg), and the open field, novelty-suppressed feeding, forced swimming, and tail suspension tests were performed after intraperitoneal injections of saline or antalarmin (20 mg/kg). The hippocampal mRNA levels of CRHR1 and nectin3 were determined by quantitative reverse transcription-PCR. The hippocampal protein levels of CRHR1, nectin3, and calbindin were measured by western blotting. The CORT (corticosterone) levels in the blood were measured by ELISA kits. RESULTS Antalarmin alleviated LPS-induced depression-like behaviour in male mice. Furthermore, antalarmin significantly inhibited changes in CRHR1, nectin3 and calbindin levels in the hippocampus and reduced the increase in CORT levels in LPS-treated mice. CONCLUSION CRHR1antagonist showed antidepressant effects in LPS-induced depressive mice, and CRHR1/nectin3 signalling may play a crucial role in this process.
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Affiliation(s)
- Jie Sun
- grid.263826.b0000 0004 1761 0489Department of Anesthesiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu China
| | - Lili Qiu
- grid.263826.b0000 0004 1761 0489Department of Anesthesiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu China
| | - Hui Zhang
- grid.263826.b0000 0004 1761 0489Department of Anesthesiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu China
| | - Zhiqiang Zhou
- grid.440259.e0000 0001 0115 7868Department of Anesthesiology, Jinling Hospital, Medical College of Nanjing Medical University, Nanjing, China
| | - Lingsha Ju
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
| | - Jiaojiao Yang
- Department of Anesthesiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
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Savi FF, de Oliveira A, de Medeiros GF, Bozza FA, Michels M, Sharshar T, Dal-Pizzol F, Ritter C. What animal models can tell us about long-term cognitive dysfunction following sepsis: A systematic review. Neurosci Biobehav Rev 2020; 124:386-404. [PMID: 33309906 DOI: 10.1016/j.neubiorev.2020.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 01/28/2023]
Abstract
Survivors of sepsis often develop long-term cognitive impairments. This review aimed at exploring the results of the behavioral tools and tests which have been used to evaluate cognitive dysfunction in different animal models of sepsis. Two independent investigators searched for sepsis- and cognition-related keywords. 6323 publications were found, of which 355 were selected based on their title, and 226 of these were chosen based on manuscript review. LPS was used to induce sepsis in 171 studies, while CLP was used in 55 studies. Inhibitory avoidance was the most widely used method for assessing aversive memory, followed by fear conditioning and continuous multi-trial inhibitory avoidance. With regard to non-aversive memory, most studies used the water maze, open-field, object recognition, Y-maze, plus maze, and radial maze tests. Both CLP and LPS models of sepsis were effective in inducing short- and long-term behavioral impairment. Our findings help elucidate the mechanisms involved in the pathophysiology of sepsis-induced cognitive changes, as well as the available methods and tests used to study this in animal models.
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Affiliation(s)
- Felipe Figueredo Savi
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil
| | - Alexandre de Oliveira
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil
| | | | - Fernando Augusto Bozza
- Laboratório de Medicina Intensiva, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Monique Michels
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil
| | - Tarek Sharshar
- Laboratoire de Neuropathologie Expérimentale, Institut Pasteur, Paris, France; Department of Neuro-Intensive Care Medicine, Sainte-Anne Hospital, Paris-Descartes University, Paris, France
| | - Felipe Dal-Pizzol
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil; Laboratoire de Neuropathologie Expérimentale, Institut Pasteur, Paris, France
| | - Cristiane Ritter
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Brazil.
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4
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Potter OV, Giedraitis ME, Johnson CD, Cox MN, Kohman RA. Young and aged TLR4 deficient mice show sex-dependent enhancements in spatial memory and alterations in interleukin-1 related genes. Brain Behav Immun 2019; 76:37-47. [PMID: 30394314 PMCID: PMC6814391 DOI: 10.1016/j.bbi.2018.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 10/04/2018] [Accepted: 10/25/2018] [Indexed: 11/19/2022] Open
Abstract
Toll-like receptor-4 (TLR4) is a transmembrane receptor that initiates an immune response following a bacterial infection or host derived molecules associated with cellular distress. Beyond triggering inflammation, TLR4 has been implicated in modulating behavioral and cognitive processes in a physiologically normal state, as young adult TLR4 deficient mice show learning enhancements in select tasks. Currently unknown is whether these benefits are present in both sexes and persist with aging. The present study evaluated spatial memory, anxiety-like behavior, and central levels of pro- and anti-inflammatory molecules in young (4-5 months) and aged (18-19 months) TLR4 deficient (TLR4-/-) and wild-type (WT) male and female mice. Results confirmed that TLR4-/- mice show enhanced spatial memory compared to WT mice. These effects were age- and sex-specific, as memory retention was superior in the TLR4-/- young males and aged females. While TLR4-/- mice showed age-related changes in behavior, these changes were attenuated relative to aged WT mice. Further, aged TLR4-/- mice showed differential expression of molecules involved in interleukin (IL)-1 signaling in the hippocampus. For instance, aged TLR4-/- females showed heightened expression of IL-1 receptor antagonist (IL-1ra) and the IL-1 accessory proteins AcP and AcPb. Collectively, these data provide the initial evidence that TLR4 deficiency enhances cognitive function and modulates the inflammatory profile of the hippocampus in a sex- and age-dependent manner.
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Affiliation(s)
- Opal V Potter
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Megan E Giedraitis
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Charles D Johnson
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Mackenzie N Cox
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Rachel A Kohman
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
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5
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Lipopolysaccharide (LPS) induced sickness in adolescent female rats alters the acute-phase response and lithium chloride (LiCl)- induced impairment of conditioned place avoidance/aversion learning, following a homotypic LPS challenge in adulthood. Behav Brain Res 2018; 351:121-130. [DOI: 10.1016/j.bbr.2018.05.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/04/2018] [Accepted: 05/29/2018] [Indexed: 02/06/2023]
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6
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Bharani KL, Derex R, Granholm AC, Ledreux A. A noradrenergic lesion aggravates the effects of systemic inflammation on the hippocampus of aged rats. PLoS One 2017; 12:e0189821. [PMID: 29261743 PMCID: PMC5736222 DOI: 10.1371/journal.pone.0189821] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/02/2017] [Indexed: 12/18/2022] Open
Abstract
Neuroinflammation is potentiated by early degeneration of the locus coeruleus noradrenergic pathway (LC-NE) commonly seen in aging-related neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. In animal models, lipopolysaccharide (LPS) induces strong peripheral immune responses that can cause cognitive changes secondary to neuroinflammation. The influence of the peripheral immune response on cognition might be exacerbated by LC-NE degeneration, but this has not been well characterized previously. In this study, we investigated how systemic inflammation affects neuroinflammation and cognition in aged rats that have had either normal or damaged LC-NE transmitter systems. Rats were first exposed to the selective noradrenergic (NE) neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) to induce degeneration of central NE pathways. Two weeks later, the rats received a low dose of LPS. This resulted in 3 treatment groups (Control, LPS-, and DSP4+LPS-treated rats) studied at 4 hours (short-term subgroup) and 7 days (long-term subgroup) following the LPS injection. DSP4+LPS-treated rats exhibited increased serum levels of several pro-inflammatory cytokines, increased astroglial and microglial activation in the hippocampus, and poorer performance in the novel object recognition task (NORT) compared to controls and LPS-treated rats. Additionally, serum and brain tissue levels of brain-derived neurotrophic factor (BDNF) were modulated over time in the DSP4+LPS group compared to the other two groups. Specifically, DSP4+LPS-treated rats in the short-term subgroup had lower hippocampal BDNF levels (~25%) than controls and LPS-treated rats, which negatively correlated with hippocampal astrogliosis and positively correlated with hippocampal IL-1β levels. Serum and hippocampal BDNF levels in the DSP4+LPS-treated rats in the long-term subgroup returned to levels similar to the control group. These results show that systemic inflammation in LC-NE-lesioned aged rats promotes an exacerbated systemic and central inflammatory response compared to LC-NE-intact rats and alters BDNF levels, indicating the important role of this neurotransmitter system in response to neuroinflammation.
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Affiliation(s)
- Krishna L. Bharani
- Department of Neurosciences, Medical University of South Carolina, BSB, Charleston, SC, United States of America
| | - Rebecca Derex
- Department of Neurosciences, Medical University of South Carolina, BSB, Charleston, SC, United States of America
| | - Ann-Charlotte Granholm
- Department of Neurosciences, Medical University of South Carolina, BSB, Charleston, SC, United States of America
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, United States of America
| | - Aurélie Ledreux
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, United States of America
- * E-mail:
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7
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Catorce MN, Gevorkian G. LPS-induced Murine Neuroinflammation Model: Main Features and Suitability for Pre-clinical Assessment of Nutraceuticals. Curr Neuropharmacol 2016; 14:155-64. [PMID: 26639457 PMCID: PMC4825946 DOI: 10.2174/1570159x14666151204122017] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 11/02/2015] [Accepted: 12/04/2015] [Indexed: 12/14/2022] Open
Abstract
Neuroinflammation is an important feature in the pathogenesis and progression of neurodegenerative diseases such as Alzheimer´s disease (AD), Parkinson´s disease (PD), frontotemporal dementia and amyotrophic lateral sclerosis. Based on current knowledge in the field, suggesting that targeting peripheral inflammation could be a promising additional treatment/prevention approach for neurodegenerative diseases, drugs and natural products with anti-inflammatory properties have been evaluated in animal models of neuroinflammation and neurodegeneration. In this review, we provide an extensive analysis of one of the most important and widely-used animal models of peripherally induced neuroinflammation and neurodegeneration - lipopolysaccharide (LPS)-treated mice, and address the data reproducibility in published research. We also summarize briefly basic features of various natural products, nutraceuticals, with known anti-inflammatory effects and present an overview of data on their therapeutic potential for reducing neuroinflammation in LPS-treated mice.
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Affiliation(s)
| | - Goar Gevorkian
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Apartado Postal 70228, Cuidad Universitaria, Mexico DF, CP 04510, Mexico.
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8
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Frühauf PKS, Ineu RP, Tomazi L, Duarte T, Mello CF, Rubin MA. Spermine reverses lipopolysaccharide-induced memory deficit in mice. J Neuroinflammation 2015; 12:3. [PMID: 25573647 PMCID: PMC4302583 DOI: 10.1186/s12974-014-0220-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/11/2014] [Indexed: 12/16/2022] Open
Abstract
Background Lipopolysaccharide (LPS) induces neuroinflammation and memory deficit. Since polyamines improve memory in various cognitive tasks, we hypothesized that spermine administration reverses LPS-induced memory deficits in an object recognition task in mice. The involvement of the polyamine binding site at the N-methyl-D-aspartate (NMDA) receptor and cytokine production in the promnesic effect of spermine were investigated. Methods Adult male mice were injected with LPS (250 μg/kg, intraperitoneally) and spermine (0.3 to 1 mg/kg, intraperitoneally) or ifenprodil (0.3 to 10 mg/kg, intraperitoneally), or both, and their memory function was evaluated using a novel object recognition task. In addition, cortical and hippocampal cytokines levels were measured by ELISA four hours after LPS injection. Results Spermine increased but ifenprodil decreased the recognition index in the novel object recognition task. Spermine, at doses that did not alter memory (0.3 mg/kg, intraperitoneally), reversed the cognitive impairment induced by LPS. Ifenprodil (0.3 mg/kg, intraperitoneally) reversed the protective effect of spermine against LPS-induced memory deficits. However, spermine failed to reverse the LPS-induced increase of cortical and hippocampal cytokine levels. Conclusions Spermine protects against LPS-induced memory deficits in mice by a mechanism that involves GluN2B receptors.
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Affiliation(s)
- Pâmella Karina Santana Frühauf
- Graduation Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil.
| | - Rafael Porto Ineu
- Graduation Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil.
| | - Lediane Tomazi
- Graduation Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil.
| | - Thiago Duarte
- Graduation Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil.
| | - Carlos Fernando Mello
- Graduation Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil. .,Department of Physiology and Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil.
| | - Maribel Antonello Rubin
- Graduation Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil. .,Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, Camobi, CEP: 97105900, Santa Maria, RS, Brazil.
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9
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Mathews SB, Arnold SE, Epperson CN. Hospitalization and cognitive decline: Can the nature of the relationship be deciphered? Am J Geriatr Psychiatry 2014; 22:465-80. [PMID: 23567430 PMCID: PMC4080837 DOI: 10.1016/j.jagp.2012.08.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 05/09/2012] [Accepted: 08/29/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND Evidence for a relationship between hospitalization and incident cognitive decline exists mainly in the literature focusing on critical care hospitalization. Recent studies, however, have also found an association between noncritical care hospitalization and the development of cognitive decline. OBJECTIVE This article will review the literature pertaining to hospitalization and cognitive decline, including hospitalizations for both critical and noncritical care, and in medical and surgical patients. The article will also explore the various factors that have been implicated in the development of cognitive decline and dementia. METHODS Review of the literature was completed using PubMed and Medline search programs. RESULTS Several articles supporting evidence for the association between hospitalization and cognitive decline are available. Evidence for potential mediating factors also does exist. CONCLUSIONS There is evidence to support an association between hospitalization and development of cognitive decline. Factors that could mediate this association include, but may not be limited to, delirium, medications, stress, and depression. There is a need for further research in this area in order to better understand the underlying pathophysiology involved in the development of cognitive decline and dementia and to determine if preventive measures might be beneficial in decreasing risk for cognitive decline for patients who are hospitalized.
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Affiliation(s)
- Sarah B Mathews
- Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA; Penn Center for Women's Behavioral Wellness, University of Pennsylvania, Philadelphia, PA.
| | - Steven E Arnold
- Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA; Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - C Neill Epperson
- Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA; Penn Center for Women's Behavioral Wellness, University of Pennsylvania, Philadelphia, PA; Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA
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10
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Kranjac D, Koster KM, Kahn MS, Eimerbrink MJ, Womble BM, Cooper BG, Chumley MJ, Boehm GW. Peripheral administration of d-cycloserine rescues memory consolidation following bacterial endotoxin exposure. Behav Brain Res 2013; 243:38-43. [DOI: 10.1016/j.bbr.2012.12.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 12/12/2022]
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11
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Kohman RA, Rhodes JS. Neurogenesis, inflammation and behavior. Brain Behav Immun 2013; 27:22-32. [PMID: 22985767 PMCID: PMC3518576 DOI: 10.1016/j.bbi.2012.09.003] [Citation(s) in RCA: 266] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/23/2012] [Accepted: 09/04/2012] [Indexed: 12/12/2022] Open
Abstract
Before the 1990s it was widely believed that the adult brain was incapable of regenerating neurons. However, it is now established that new neurons are continuously produced in the dentate gyrus of the hippocampus and olfactory bulb throughout life. The functional significance of adult neurogenesis is still unclear, but it is widely believed that the new neurons contribute to learning and memory and/or maintenance of brain regions by replacing dead or dying cells. Many different factors are known to regulate adult neurogenesis including immune responses and signaling molecules released by immune cells in the brain. While immune activation (i.e., enlargement of microglia, release of cytokines) within the brain is commonly viewed as a harmful event, the impact of immune activation on neural function is highly dependent on the form of the immune response as microglia and other immune-reactive cells in the brain can support or disrupt neural processes depending on the phenotype and behavior of the cells. For instance, microglia that express an inflammatory phenotype generally reduce cell proliferation, survival and function of new neurons whereas microglia displaying an alternative protective phenotype support adult neurogenesis. The present review summarizes current understanding of the role of new neurons in cognition and behavior, with an emphasis on the immune system's ability to influence adult hippocampal neurogenesis during both an inflammatory episode and in the healthy uninjured brain. It has been proposed that some of the cognitive deficits associated with inflammation may in part be related to inflammation-induced reductions in adult hippocampal neurogenesis. Elucidating how the immune system contributes to the regulation of adult neurogenesis will help in predicting the impact of immune activation on neural plasticity and potentially facilitate the discovery of treatments to preserve neurogenesis in conditions characterized by chronic inflammation.
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12
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Rana SA, Aavani T, Pittman QJ. Sex effects on neurodevelopmental outcomes of innate immune activation during prenatal and neonatal life. Horm Behav 2012; 62:228-36. [PMID: 22516179 PMCID: PMC3522744 DOI: 10.1016/j.yhbeh.2012.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/25/2012] [Accepted: 03/28/2012] [Indexed: 11/15/2022]
Abstract
Humans are exposed to potentially harmful agents (bacteria, viruses, toxins) throughout our lifespan; the consequences of such exposure can alter central nervous system development. Exposure to immunogens during pregnancy increases the risk of developing neurological disorders such as schizophrenia and autism. Further, sex hormones, such as estrogen, have strong modulatory effects on immune function and have also been implicated in the development of neuropathologies (e.g., schizophrenia and depression). Similarly, animal studies have demonstrated that immunogen exposure in utero or during the neonatal period, at a time when the brain is undergoing maturation, can induce changes in learning and memory, as well as dopamine-mediated behaviors in a sex-specific manner. Literature that covers the effects of immunogens on innate immune activation and ultimately the development of the adult brain and behavior is riddled with contradictory findings, and the addition of sex as a factor only adds to the complexity. This review provides evidence that innate immune activation during critical periods of development may have effects on the adult brain in a sex-specific manner. Issues regarding sex bias in research as well as variability in animal models of immune function are discussed.
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Affiliation(s)
| | | | - Quentin J. Pittman
- Corresponding author at: Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada. Fax: +1 403 283 2700. (Q.J. Pittman)
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13
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Kahn MS, Kranjac D, Alonzo CA, Haase JH, Cedillos RO, McLinden KA, Boehm GW, Chumley MJ. Prolonged elevation in hippocampal Aβ and cognitive deficits following repeated endotoxin exposure in the mouse. Behav Brain Res 2012; 229:176-84. [DOI: 10.1016/j.bbr.2012.01.010] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 12/20/2011] [Accepted: 01/04/2012] [Indexed: 12/12/2022]
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14
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Kranjac D, McLinden KA, Deodati LE, Papini MR, Chumley MJ, Boehm GW. Peripheral bacterial endotoxin administration triggers both memory consolidation and reconsolidation deficits in mice. Brain Behav Immun 2012; 26:109-21. [PMID: 21889586 DOI: 10.1016/j.bbi.2011.08.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/18/2011] [Accepted: 08/18/2011] [Indexed: 10/17/2022] Open
Abstract
Peripherally administered inflammatory stimuli, such as lipopolysaccharide (LPS), induce the synthesis and release of proinflammatory cytokines and chemokines in the periphery and the central nervous system, and trigger a variety of neurobiological responses. Indeed, prior reports indicate that peripheral LPS administration in rats disrupts contextual fear memory consolidation processes, potentially due to elevated cytokine expression. We used a similar, but partially olfaction-based, contextual fear conditioning paradigm to examine the effects of LPS on memory consolidation and reconsolidation in mice. Additionally, interleukin-1β (IL-1β), brain-derived neurotrophic factor (BDNF), and zinc finger (Zif)-268 mRNA expression in the hippocampus and the cortex, along with peripheral cytokines and chemokines, were assessed. As hypothesized, LPS administered immediately or 2 h, but not 12 h, post-training impaired memory consolidation processes that support the storage of the conditioned contextual fear memory. Additionally, as hypothesized, LPS administered immediately following the fear memory trace reactivation session impaired memory reconsolidation processes. Four hours post-injection, both central cytokine and peripheral cytokine and chemokine levels were heightened in LPS-treated animals, with a simultaneous decrease in BDNF, but not Zif-268, mRNA. Collectively, these data reinforce prior work showing LPS- and cytokine-related effects on memory consolidation, and extend this work to memory reconsolidation.
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Affiliation(s)
- Dinko Kranjac
- Department of Psychology, Texas Christian University, Fort Worth, TX 76129, USA
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Abstract
Over the years it has become evident that the immune system can affect the function of the central nervous system (CNS), including altering cognitive processes. The impact of immune activation on the CNS is particularly important for aged individuals, as the brain's resident immune cells, microglia, acquire a pro-inflammatory profile. The low-grade chronic neuroinflammation that develops with normal aging likely contributes to the susceptibility to cognitive deficits and a host of age-related pathologies. Understanding why microglia show increased inflammatory activity (i.e., neuroinflammation) and identifying effective treatments to reduce microglia activation is expected to have beneficial effects on cognitive performance and measures of neural plasticity. However, microglia also promote regeneration after injury. Therefore, effective treatments must dampen inflammatory activity while preserving microglia's neuroprotective function. Discovering factors that induce neuroinflammation and investigating potential preventative therapies is expected to uncover the ways of maintaining normal microglia activity in the aged brain.
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Affiliation(s)
- Rachel A Kohman
- Department of Psychology, University of Illinois at Urbana-Champaign, Beckman Institute, Urbana, IL, USA.
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Knapp DJ, Whitman BA, Wills TA, Angel RA, Overstreet DH, Criswell HE, Ming Z, Breese GR. Cytokine involvement in stress may depend on corticotrophin releasing factor to sensitize ethanol withdrawal anxiety. Brain Behav Immun 2011; 25 Suppl 1:S146-54. [PMID: 21377524 PMCID: PMC3138123 DOI: 10.1016/j.bbi.2011.02.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/27/2011] [Accepted: 02/28/2011] [Indexed: 12/23/2022] Open
Abstract
Stress has been shown to facilitate ethanol withdrawal-induced anxiety. Defining neurobiological mechanisms through which stress has such actions is important given the associated risk of relapse. While CRF has long been implicated in the action of stress, current results show that stress elevates the cytokine TNFα in the rat brain and thereby implicates cytokines in stress effects. In support of this view, prior TNFα microinjection into the central amygdala (CeA) of rats facilitated ethanol withdrawal-induced anxiety-a response that could not be attributed to an increase in plasma corticosterone. To test for a possible interaction between cytokines and CRF, a CRF1-receptor antagonist (SSR125543) administered prior to the repeated administration of TNFα or MCP-1/CCL2 reduced the magnitude of the withdrawal-induced anxiety. This finding provided evidence for cytokine action being dependent upon CRF. Additionally, the sensitizing effect of stress on withdrawal-induced anxiety was reduced by treating the repeated stress exposure prior to ethanol with the MEK inhibitor SL327. Consistent with cytokines having a neuromediator function distinct from a neuroimmune action, TNFα increased firing rate and GABA release from CeA neurons. Thus, an interaction of glial and neuronal function is proposed to contribute to the interaction of stress and chronic ethanol. Interrupting this potential glial-neuronal interaction could provide a novel means by which to alter the development of emotional states induced by stress that predict relapse in the alcoholic.
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Affiliation(s)
- Darin J. Knapp
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Corresponding Author: Darin J. Knapp, PhD. CB 7178, University of North Carolina, Chapel Hill, NC 27599, ; Phone: 919-966-0505; Fax: 919-966-5679
| | - Buddy A. Whitman
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Tiffany A. Wills
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Robert A. Angel
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - David H. Overstreet
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Hugh E. Criswell
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Zhen Ming
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - George R. Breese
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599
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Neonatal endotoxin exposure impairs avoidance learning and attenuates endotoxin-induced sickness behavior and central IL-1β gene transcription in adulthood. Behav Brain Res 2008; 194:25-31. [DOI: 10.1016/j.bbr.2008.06.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 05/21/2008] [Accepted: 06/18/2008] [Indexed: 12/12/2022]
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18
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Kohman RA, Tarr AJ, Day CE, McLinden KA, Boehm GW. Influence of prenatal stress on behavioral, endocrine, and cytokine responses to adulthood bacterial endotoxin exposure. Behav Brain Res 2008; 193:257-68. [DOI: 10.1016/j.bbr.2008.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 05/27/2008] [Accepted: 06/05/2008] [Indexed: 12/13/2022]
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Maclullich AMJ, Ferguson KJ, Miller T, de Rooij SEJA, Cunningham C. Unravelling the pathophysiology of delirium: a focus on the role of aberrant stress responses. J Psychosom Res 2008; 65:229-38. [PMID: 18707945 PMCID: PMC4311661 DOI: 10.1016/j.jpsychores.2008.05.019] [Citation(s) in RCA: 266] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 05/09/2008] [Accepted: 05/15/2008] [Indexed: 01/01/2023]
Abstract
Delirium is a common and serious acute neuropsychiatric syndrome with core features of inattention and cognitive impairment, and associated features including changes in arousal, altered sleep-wake cycle, and other changes in mental status. The main risk factors are old age, cognitive impairment, and other comorbidities. Though delirium has consistent core clinical features, it has a very wide range of precipitating factors, including acute illness, surgery, trauma, and drugs. The molecular mechanisms by which these precipitating factors lead to delirium are largely obscure. In this article, we attempt to narrow down some specific causal pathways. We propose a basic classification for the etiological factors: (a) direct brain insults and (b) aberrant stress responses. Direct brain insults are largely indiscriminate and include general and regional energy deprivation (e.g., hypoxia, hypoglycaemia, stroke), metabolic abnormalities (e.g., hyponatraemia, hypercalcaemia), and the effects of drugs. Aberrant stress responses are conceptually and mechanistically distinct in that they constitute adverse effects of stress-response pathways, which, in health, are adaptive. Ageing and central nervous system disease, two major predisposing factors for delirium, are associated with alterations in the magnitude or duration of stress and sickness behavior responses and increased vulnerability to the effects of these responses. We discuss in detail two stress response systems that are likely to be involved in the pathophysiology of delirium: inflammation and the sickness behavior response, and activity of the limbic-hypothalamic-pituitary-adrenal axis. We conclude by discussing the implications for future research and the development of new therapies for delirium.
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Affiliation(s)
- Alasdair M J Maclullich
- Geriatric Medicine/MRC Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, Scotland, UK.
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