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Viscarra F, Chrestia JF, Sanchez Y, Pérez EG, Biggin PC, Bouzat C, Bermudez I, López JJ. Side Groups Convert the α7 Nicotinic Receptor Agonist Ether Quinuclidine into a Type I Positive Allosteric Modulator. ACS Chem Neurosci 2023; 14:2876-2887. [PMID: 37535446 DOI: 10.1021/acschemneuro.3c00225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023] Open
Abstract
The quinuclidine scaffold has been extensively used for the development of nicotinic acetylcholine receptor (nAChR) agonists, with hydrophobic substituents at position 3 of the quinuclidine framework providing selectivity for α7 nAChRs. In this study, six new ligands (4-9) containing a 3-(pyridin-3-yloxy)quinuclidine moiety (ether quinuclidine) were synthesized to gain a better understanding of the structural-functional properties of ether quinuclidines. To evaluate the pharmacological activity of these ligands, two-electrode voltage-clamp and single-channel recordings were performed. Only ligand 4 activated α7 nAChR. Ligands 5 and 7 had no effects on α7 nAChR, but ligands 6, 8, and 9 potentiated the currents evoked by ACh. Ligand 6 was the most potent and efficacious of the potentiating ligands, with an estimated EC50 for potentiation of 12.6 ± 3.32 μM and a maximal potentiation of EC20 ACh responses of 850 ± 120%. Ligand 6 increased the maximal ACh responses without changing the kinetics of the current responses. At the single-channel level, the potentiation exerted by ligand 6 was evidenced in the low micromolar concentration range by the appearance of prolonged bursts of channel openings. Furthermore, computational studies revealed the preference of ligand 6 for an intersubunit site in the transmembrane domain and highlighted some putative key interactions that explain the different profiles of the synthesized ligands. Notably, Met276 in the 15' position of the transmembrane domain 2 almost abolished the effects of ligand 6 when mutated to Leu. We conclude that ligand 6 is a novel type I positive allosteric modulator (PAM-I) of α7 nAChR.
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Affiliation(s)
- Franco Viscarra
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, U.K
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, Oxford University, South Parks Road, Oxford OX1 3QU, U.K
| | - Juan Facundo Chrestia
- Departamento de Biología, Bioquímica y Farmacia, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km 7, Bahía Blanca 8000, Argentina
| | - Yaima Sanchez
- Department of Organic Chemistry, Faculty of Chemistry, Universidad de Concepción, Edmundo Larenas 129, Concepción 4070371, Chile
| | - Edwin G Pérez
- Department of Organic Chemistry, Faculty of Chemistry and Pharmacy, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago 7820436, Chile
| | - Philip C Biggin
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, Oxford University, South Parks Road, Oxford OX1 3QU, U.K
| | - Cecilia Bouzat
- Departamento de Biología, Bioquímica y Farmacia, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km 7, Bahía Blanca 8000, Argentina
| | - Isabel Bermudez
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, U.K
| | - Jhon J López
- Department of Organic Chemistry, Faculty of Chemistry, Universidad de Concepción, Edmundo Larenas 129, Concepción 4070371, Chile
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Keever KR, Yakubenko VP, Hoover DB. Neuroimmune nexus in the pathophysiology and therapy of inflammatory disorders: role of α7 nicotinic acetylcholine receptors. Pharmacol Res 2023; 191:106758. [PMID: 37028776 DOI: 10.1016/j.phrs.2023.106758] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/30/2023] [Accepted: 04/02/2023] [Indexed: 04/08/2023]
Abstract
The α7-nicotinic acetylcholine receptor (α7nAChR) is a key protein in the cholinergic anti-inflammatory pathway (CAP) that links the nervous and immune systems. Initially, the pathway was discovered based on the observation that vagal nerve stimulation (VNS) reduced the systemic inflammatory response in septic animals. Subsequent studies form a foundation for the leading hypothesis about the central role of the spleen in CAP activation. VNS evokes noradrenergic stimulation of ACh release from T cells in the spleen, which in turn activates α7nAChRs on the surface of macrophages. α7nAChR-mediated signaling in macrophages reduces inflammatory cytokine secretion and modifies apoptosis, proliferation, and macrophage polarization, eventually reducing the systemic inflammatory response. A protective role of the CAP has been demonstrated in preclinical studies for multiple diseases including sepsis, metabolic disease, cardiovascular diseases, arthritis, Crohn's disease, ulcerative colitis, endometriosis, and potentially COVID-19, sparking interest in using bioelectronic and pharmacological approaches to target α7nAChRs for treating inflammatory conditions in patients. Despite a keen interest, many aspects of the cholinergic pathway are still unknown. α7nAChRs are expressed on many other subsets of immune cells that can affect the development of inflammation differently. There are also other sources of ACh that modify immune cell functions. How the interplay of ACh and α7nAChR on different cells and in various tissues contributes to the anti-inflammatory responses requires additional study. This review provides an update on basic and translational studies of the CAP in inflammatory diseases, the relevant pharmacology of α7nAChR-activated drugs and raises some questions that require further investigation.
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Fielding C, García-García A, Korn C, Gadomski S, Fang Z, Reguera JL, Pérez-Simón JA, Göttgens B, Méndez-Ferrer S. Cholinergic signals preserve haematopoietic stem cell quiescence during regenerative haematopoiesis. Nat Commun 2022; 13:543. [PMID: 35087060 PMCID: PMC8795384 DOI: 10.1038/s41467-022-28175-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 01/12/2022] [Indexed: 12/15/2022] Open
Abstract
The sympathetic nervous system has been evolutionary selected to respond to stress and activates haematopoietic stem cells via noradrenergic signals. However, the pathways preserving haematopoietic stem cell quiescence and maintenance under proliferative stress remain largely unknown. Here we found that cholinergic signals preserve haematopoietic stem cell quiescence in bone-associated (endosteal) bone marrow niches. Bone marrow cholinergic neural signals increase during stress haematopoiesis and are amplified through cholinergic osteoprogenitors. Lack of cholinergic innervation impairs balanced responses to chemotherapy or irradiation and reduces haematopoietic stem cell quiescence and self-renewal. Cholinergic signals activate α7 nicotinic receptor in bone marrow mesenchymal stromal cells leading to increased CXCL12 expression and haematopoietic stem cell quiescence. Consequently, nicotine exposure increases endosteal haematopoietic stem cell quiescence in vivo and impairs hematopoietic regeneration after haematopoietic stem cell transplantation in mice. In humans, smoking history is associated with delayed normalisation of platelet counts after allogeneic haematopoietic stem cell transplantation. These results suggest that cholinergic signals preserve stem cell quiescence under proliferative stress.
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Affiliation(s)
- Claire Fielding
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK
| | - Andrés García-García
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK
| | - Claudia Korn
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK
| | - Stephen Gadomski
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK
- Skeletal Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, 20892, USA
- NIH-Oxford-Cambridge Scholars Program in partnership with Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Zijian Fang
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK
| | - Juan L Reguera
- Department of Hematology, University Hospital Virgen del Rocio, 41013, Sevilla, Spain
| | - José A Pérez-Simón
- NIH-Oxford-Cambridge Scholars Program in partnership with Medical University of South Carolina, Charleston, SC, 29425, USA
- Department of Hematology, University Hospital Virgen del Rocio, 41013, Sevilla, Spain
| | - Berthold Göttgens
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK
| | - Simón Méndez-Ferrer
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, CB2 0AW, UK.
- Department of Hematology, University of Cambridge, Cambridge, CB2 0AW, UK.
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK.
- Instituto de Biomedicina de Sevilla (IBiS/CSIC), Universidad de Sevilla, 41013, Seville, Spain.
- Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, 41009, Seville, Spain.
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Rogers SW, Myers EJ, Gahring LC. Age-Associated Tooth Loss and Oral Microbial Dysbiosis in a Mouse Genetic Model of Chronic Nicotine Exposure. Front Immunol 2020; 11:575200. [PMID: 33117372 PMCID: PMC7575759 DOI: 10.3389/fimmu.2020.575200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/08/2020] [Indexed: 11/13/2022] Open
Abstract
Nicotine acts as a potent modulator of normal cellular responses through the nicotinic acetylcholine receptor subtype alpha7. In a mouse genetic model of alpha7 receptor dysfunction, alpha7E260A:G, 85 percent of 18 month-old mice exhibit an age-associated spontaneous loosening or complete loss of 3rd molars that was not present in the control mice. The adjacent soft tissues appeared largely unaffected. Further analysis including micro-CT revealed evidence of bone loss surrounding the 3rd molars with areas of cavitation and/or sponge-like (cancellous) bone remodeling in the mandible. The mandible microbiome was examined using 16S-rRNA sequencing. The results show the alpha7E260A:G oral microbiome included increased landscape complexity indicative of dysbiosis, and a significant increase of some bacteria, particularly Staphylococcus. These results suggest that normal alpha7 function plays a relevant role in maintaining normal gene expression and oral microbiome stasis. Consequently, this mouse model suggests there are consequences to ongoing alpha7 receptor dysfunction and oral health, as can occur from chronic exposure to nicotine as expected from electronic nicotine delivery systems (ENDS or "vaping"), that may not be seen until older age.
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Affiliation(s)
- Scott W Rogers
- Salt Lake City Veterans Affairs Medical Center: Geriatrics, Research, Education and Clinical Center, Salt Lake City, UT, United States.,Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Elizabeth J Myers
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Lorise C Gahring
- Salt Lake City Veterans Affairs Medical Center: Geriatrics, Research, Education and Clinical Center, Salt Lake City, UT, United States.,Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT, United States
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Qi Y, Si D, Zhu L, Qi Y, Wu Z, Chen D, Yang Y. High-fat diet-induced obesity affects alpha 7 nicotine acetylcholine receptor expressions in mouse lung myeloid cells. Sci Rep 2020; 10:18368. [PMID: 33110180 DOI: 10.1038/s41598-020-75414-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 10/14/2020] [Indexed: 12/16/2022] Open
Abstract
Ample evidence indicates that obesity causes dysfunctions in the lung. Previous studies also show that cholinergic anti-inflammatory pathways play crucial roles in obesity-induced chronic inflammation via α7 nicotinic acetylcholine receptor (α7nAChR) signaling. However, it remains unclear whether and how obesity affects the expressions of α7nAChR in myeloid cells in the lung. To address this question, we treated regular chow diet-fed mice or high-fat diet induced obese mice with lipopolysaccharide (LPS) or vehicle via endotracheal injections. By using a multicolor flow cytometry approach to analyze and characterize differential cell subpopulations and α7nAChR expressions, we find no detectable α7nAChR in granulocytes, monocytes and alveolar macrophages, and low expression levels of α7nAChR were detected in interstitial macrophages. Interestingly, we find that a challenge with LPS treatment significantly increased expression levels of α7nAChR in monocytes, alveolar and interstitial macrophages. Meanwhile, we observed that the expression levels of α7nAChR in alveolar and interstitial macrophages in high-fat diet induced obese mice were lower than regular chow diet-fed mice challenged by the LPS. Together, our findings indicate that obesity alters the expressions of α7nAChR in differential lung myeloid cells.
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Gahring LC, Myers EJ, Rogers SW. Inhaled aerosolized nicotine suppresses the lung eosinophilic response to house dust mite allergen. Am J Physiol Lung Cell Mol Physiol 2020; 319:L683-L692. [PMID: 32726138 DOI: 10.1152/ajplung.00227.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nicotine of unprecedented concentrations and purity is being inhaled by those using commercially available electronic nicotine delivery systems (ENDS). The consequences of this route of self-administration on the immunological response to inhaled allergens are not known. In mice, sensitization and inhalation challenge with the common environmental house dust mite (HDM) allergen is an experimental model of this response. When mice were exposed to aerosolized nicotine base (aeroNic) twice daily, 5 days/wk for 8 wk, the HDM-induced recruitment of eosinophils (EOS) was substantially reduced as measured in bronchial alveolar lavage fluid (BALF). Oral nicotine administration had no effect. HDM challenge in the presence of nicotinic receptor subtype α7 (α7)-specific type-1 positive allosteric modulators (PAMs) was alone sufficient to suppress EOS. RNA analysis of alveolar macrophages (AM) collected from BALF after HDM challenge of aeroNic revealed that α7 activation strongly suppresses initiation of Ccl24 (eotaxin 2) transcription. To examine possible cellular signaling mechanisms coupling α7 to Ccl24 transcription, an AM culture model system was used. In AM cultures of freshly collected BALF, Ccl24 transcription was robustly activated by a mixture of IL-4 and IL-10, and this was suppressed by coapplication of type-1 PAMs through a pathway that requires p38MAPK but is independent of Jak2. These results suggest that the EOS response to HDM inhaled allergen is subject to modulation through activation of the α7 receptor and suggest that the allergic response may be substantially modified in ENDS users.
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Affiliation(s)
- Lorise C Gahring
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Administration Medical Center, Salt Lake City, Utah.,Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Elizabeth J Myers
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Scott W Rogers
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Administration Medical Center, Salt Lake City, Utah.,Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah
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Medinaceli Quintela R, Bauer J, Wallhorn L, Le K, Brunert D, Rothermel M. Dynamic Impairment of Olfactory Behavior and Signaling Mediated by an Olfactory Corticofugal System. J Neurosci 2020; 40:7269-85. [PMID: 32817250 DOI: 10.1523/JNEUROSCI.2667-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 06/30/2020] [Accepted: 07/05/2020] [Indexed: 01/16/2023] Open
Abstract
Processing of olfactory information is modulated by centrifugal projections from cortical areas, yet their behavioral relevance and underlying neural mechanisms remain unclear in most cases. The anterior olfactory nucleus (AON) is part of the olfactory cortex, and its extensive connections to multiple upstream and downstream brain centers place it in a prime position to modulate early sensory information in the olfactory system. Here, we show that optogenetic activation of AON neurons in awake male and female mice was not perceived as an odorant equivalent cue. However, AON activation during odorant presentation reliably suppressed behavioral odor responses. This AON-mediated effect was fast and constant across odors and concentrations. Likewise, activation of glutamatergic AON projections to the olfactory bulb (OB) transiently inhibited the excitability of mitral/tufted cells (MTCs) that relay olfactory input to the cortex. Single-unit MTC recordings revealed that optogenetic activation of glutamatergic AON terminals in the OB transiently decreased sensory-evoked MTC spiking, regardless of the strength or polarity of the sensory response. The reduction in MTC firing during optogenetic stimulation was confirmed in recordings in awake mice. These findings suggest that glutamatergic AON projections to the OB impede early olfactory signaling by inhibiting OB output neurons, thereby dynamically gating sensory throughput to the cortex.SIGNIFICANCE STATEMENT The anterior olfactory nucleus (AON) as an olfactory information processing area sends extensive projections to multiple brain centers, but the behavioral consequences of its activation have been scarcely investigated. Using behavioral tests in combination with optogenetic manipulation, we show that, in contrast to what has been suggested previously, the AON does not seem to form odor percepts but instead suppresses behavioral odor responses across odorants and concentrations. Furthermore, this study shows that AON activation inhibits olfactory bulb output neurons in both anesthetized as well as awake mice, pointing to a potential mechanism by which the olfactory cortex can actively and dynamically gate sensory throughput to higher brain centers.
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Abdelzaher LA, Hussein OA, Ashry IEM. The Novel Potential Therapeutic Utility of Montelukast in Alleviating Autistic Behavior Induced by Early Postnatal Administration of Thimerosal in Mice. Cell Mol Neurobiol 2020; 41:129-150. [PMID: 32303879 DOI: 10.1007/s10571-020-00841-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 04/01/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIM: Thimerosal (THIM) is a mercury-containing preservative widely used in many biological and medical products including many vaccines. It has been accused of being a possible etiological factor for some neurodevelopmental disorders such as autistic spectrum disorders (ASDs). In our study, the potential therapeutic effect of montelukast, a leukotriene receptor antagonist used to treat seasonal allergies and asthma, on THIM mice model (ASDs model) was examined. METHODOLOGY Newborn mice were randomly distributed into three groups: (Group 1) Control (Cont.) group received saline injections. (Group 2) THIM-treated (THIM) group received THIM intramuscular (IM) at a dose of 3000 μg Hg/kg on postnatal days 7, 9, 11, and 15. (Group 3) Montelukast-treated (Monte) group received THIM followed by montelukast sodium (10 mg/kg/day) intraperitoneal (IP) for 3 weeks. Mice were evaluated for growth development, social interactions, anxiety, locomotor activity, and cognitive function. Brain histopathology, alpha 7 nicotinic acetylcholine receptors (α7nAChRs), nuclear factor kappa B p65 (NF-κB p65), apoptotic factor (Bax), and brain injury markers were evaluated as well. RESULTS THIIM significantly impaired social activity and growth development. Montelukast mitigated THIM-induced social deficit probably through α7nAChRs upregulation, NF-κB p65, Bax, and brain injury markers downregulation, thus suppressing THIM-induced neuronal toxicity and inflammation. CONCLUSION Neonatal exposure to THIM can induce growth retardation and abnormal social interactions similar to those observed in ASDs. Some of these abnormalities could be ameliorated by montelukast via upregulation of α7nAChRs that inhibited NF-κB activation and significant suppression of neuronal injury and the associated apoptosis.
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Affiliation(s)
- Lobna A Abdelzaher
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt.
| | - Ola A Hussein
- Department of Histology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - I E M Ashry
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Costantini TW, Chan TW, Cohen O, Langness S, Treadwell S, Williams E, Eliceiri BP, Baird A. Uniquely human CHRFAM7A gene increases the hematopoietic stem cell reservoir in mice and amplifies their inflammatory response. Proc Natl Acad Sci U S A 2019; 116:7932-40. [PMID: 30944217 DOI: 10.1073/pnas.1821853116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The emergence of uniquely human genes during hominid speciation enabled numerous human-specific adaptations that presumably included changes in resilience to disease but potentially increased susceptibility as well. Here we show that the transgenic expression of one such gene, called CHRFAM7A, changes the mouse reservoir of hematopoietic stem cells in bone marrow and amplifies the mouse inflammatory response in a model of human systemic inflammatory response syndrome (SIRS). Because the CHRFAM7A gene is a dominant-negative inhibitor of ligand binding to α7 nicotinic acetylcholine receptor (α7nAChR), a neurotransmitter receptor implicated in immunity, inflammation, neurodegeneration, and cognitive function, the results underscore the importance of understanding the contribution of species-specific genes to human disease and the impact they may have on the fidelity of animal models for translational medicine. A subset of genes in the human genome are uniquely human and not found in other species. One example is CHRFAM7A, a dominant-negative inhibitor of the antiinflammatory α7 nicotinic acetylcholine receptor (α7nAChR/CHRNA7) that is also a neurotransmitter receptor linked to cognitive function, mental health, and neurodegenerative disease. Here we show that CHRFAM7A blocks ligand binding to both mouse and human α7nAChR, and hypothesized that CHRFAM7A-transgenic mice would allow us to study its biological significance in a tractable animal model of human inflammatory disease, namely SIRS, the systemic inflammatory response syndrome that accompanies severe injury and sepsis. We found that CHRFAM7A increased the hematopoietic stem cell (HSC) reservoir in bone marrow and biased HSC differentiation to the monocyte lineage in vitro. We also observed that while the HSC reservoir was depleted in SIRS, HSCs were spared in CHRFAM7A-transgenic mice and that these mice also had increased immune cell mobilization, myeloid cell differentiation, and a shift to inflammatory monocytes from granulocytes in their inflamed lungs. Together, the findings point to a pathophysiological inflammatory consequence to the emergence of CHRFAM7A in the human genome. To this end, it is interesting to speculate that human genes like CHRFAM7A can account for discrepancies between the effectiveness of drugs like α7nAChR agonists in animal models and human clinical trials for inflammatory and neurodegenerative disease. The findings also support the hypothesis that uniquely human genes may be contributing to underrecognized human-specific differences in resiliency/susceptibility to complications of injury, infection, and inflammation, not to mention the onset of neurodegenerative disease.
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Gahring LC, Myers EJ, Dunn DM, Weiss RB, Rogers SW. Lung eosinophilia induced by house dust mites or ovalbumin is modulated by nicotinic receptor α7 and inhibited by cigarette smoke. Am J Physiol Lung Cell Mol Physiol 2018; 315:L553-L562. [PMID: 29975102 PMCID: PMC6230881 DOI: 10.1152/ajplung.00230.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/21/2018] [Accepted: 07/03/2018] [Indexed: 12/16/2022] Open
Abstract
Eosinophilia (EOS) is an important component of airway inflammation and hyperresponsiveness in allergic reactions including those leading to asthma. Although cigarette smoking (CS) is a significant contributor to long-term adverse outcomes in these lung disorders, there are also the curious reports of its ability to produce acute suppression of inflammatory responses including EOS through poorly understood mechanisms. One possibility is that proinflammatory processes are suppressed by nicotine in CS acting through nicotinic receptor α7 (α7). Here we addressed the role of α7 in modulating EOS with two mouse models of an allergic response: house dust mites (HDM; Dermatophagoides sp.) and ovalbumin (OVA). The influence of α7 on EOS was experimentally resolved in wild-type mice or in mice in which a point mutation of the α7 receptor (α7E260A:G) selectively restricts normal signaling of cellular responses. RNA analysis of alveolar macrophages and the distal lung epithelium indicates that normal α7 function robustly impacts gene expression in the epithelium to HDM and OVA but to different degrees. Notable was allergen-specific α7 modulation of Ccl11 and Ccl24 (eotaxins) expression, which was enhanced in HDM but suppressed in OVA EOS. CS suppressed EOS induced by both OVA and HDM, as well as the inflammatory genes involved, regardless of α7 genotype. These results suggest that EOS in response to HDM or OVA is through signaling pathways that are modulated in a cell-specific manner by α7 and are distinct from CS suppression.
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Affiliation(s)
- Lorise C Gahring
- Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center , Salt Lake City, Utah
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine , Salt Lake City, Utah
| | - Elizabeth J Myers
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine , Salt Lake City, Utah
| | - Diane M Dunn
- Department of Human Genetics, University of Utah School of Medicine , Salt Lake City, Utah
| | - Robert B Weiss
- Department of Human Genetics, University of Utah School of Medicine , Salt Lake City, Utah
| | - Scott W Rogers
- Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center , Salt Lake City, Utah
- Department of Neurobiology and Anatomy, University of Utah School of Medicine , Salt Lake City, Utah
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Gahring LC, Myers EJ, Dunn DM, Weiss RB, Rogers SW. Lung epithelial response to cigarette smoke and modulation by the nicotinic alpha 7 receptor. PLoS One 2017; 12:e0187773. [PMID: 29117258 DOI: 10.1371/journal.pone.0187773] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/25/2017] [Indexed: 12/19/2022] Open
Abstract
Cigarette smoking (CS) is a principal contributor to a spectrum of devastating lung diseases whose occurrence and severity may vary between individuals and not appear for decades after prolonged use. One explanation for the variability and delay in disease onset is that nicotine, the addictive component of CS, acts through the ionotropic nicotinic acetylcholine receptor (nAChR) alpha7 (α7) to modulate anti-inflammatory protection. In this study we measured the impact α7 signaling has on the mouse distal lung response to side-stream CS exposure for mice of the control genotype (α7G) and those in which the α7-receptor signaling mechanisms are restricted by point mutation (α7E260A:G). Flow cytometry results show that after CS there is an increase in a subset of CD11c (CD11chi) alveolar macrophages (AMs) and histology reveals an increase in these cells within the alveolar space in both genotypes although the α7E260A:G AMs tend to accumulate into large aggregates rather than more widely distributed solitary cells common to the α7G lung after CS. Changes to lung morphology with CS in both genotypes included increased tissue cavitation due to alveolar expansion and bronchial epithelium dysplasia in part associated with altered club cell morphology. RNA-Seq analysis revealed changes in epithelium gene expression after CS are largely independent of the α7-genotype. However, the α7E260A:G genotype did reveal some unique variations to transcript expression of gene sets associated with immune responsiveness and macrophage recruitment, hypoxia, genes encoding mitochondrial respiration complex I and extracellular fibrillary matrix proteins (including alterations to fibrotic deposits in the α7G proximal airway bronchioles after CS). These results suggest α7 has a central role in modulating the response to chronic CS that could include altering susceptibility to associated lung diseases including fibrosis and cancer.
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Bai X, Stitzel JA, Bai A, Zambrano CA, Phillips M, Marrack P, Chan ED. Nicotine Impairs Macrophage Control of Mycobacterium tuberculosis. Am J Respir Cell Mol Biol 2017; 57:324-333. [PMID: 28398760 DOI: 10.1165/rcmb.2016-0270oc] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Pure nicotine impairs macrophage killing of Mycobacterium tuberculosis (MTB), but it is not known whether the nicotine component in cigarette smoke (CS) plays a role. Moreover, the mechanisms by which nicotine impairs macrophage immunity against MTB have not been explored. To neutralize the effects of nicotine in CS extract, we used a competitive inhibitor to the nicotinic acetylcholine receptor (nAChR)-mecamylamine-as well as macrophages derived from mice with genetic disruption of specific subunits of nAChR. We also determined whether nicotine impaired macrophage autophagy and whether nicotine-exposed T regulatory cells (Tregs) could subvert macrophage anti-MTB immunity. Mecamylamine reduced the CS extract increase in MTB burden by 43%. CS extract increase in MTB was also significantly attenuated in macrophages from mice with genetic disruption of either the α7, β2, or β4 subunit of nAChR. Nicotine inhibited autophagosome formation in MTB-infected THP-1 cells and primary murine alveolar macrophages, as well as increased the intracellular MTB burden. Nicotine increased migration of THP-1 cells, consistent with the increased number of macrophages found in the lungs of smokers. Nicotine induced Tregs to produce transforming growth factor-β. Naive mouse macrophages co-cultured with nicotine-exposed Tregs had significantly greater numbers of viable MTB recovered with increased IL-10 production and urea production, but no difference in secreted nitric oxide as compared with macrophages cocultured with unexposed Tregs. We conclude that nicotine in CS plays an important role in subverting macrophage control of MTB infection.
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Affiliation(s)
- Xiyuan Bai
- 1 Department of Medicine, Denver Veterans Affairs Medical Center, Denver, Colorado.,Departments of 2 Medicine.,3 Academic Affairs, and.,4 Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Jerry A Stitzel
- 5 Department of Integrative Physiology, Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, Colorado
| | - An Bai
- 1 Department of Medicine, Denver Veterans Affairs Medical Center, Denver, Colorado.,Departments of 2 Medicine.,3 Academic Affairs, and
| | - Cristian A Zambrano
- 5 Department of Integrative Physiology, Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, Colorado
| | | | - Philippa Marrack
- 6 Immunology, and.,7 Howard Hughes Medical Institute, National Jewish Health, Denver, Colorado
| | - Edward D Chan
- 1 Department of Medicine, Denver Veterans Affairs Medical Center, Denver, Colorado.,Departments of 2 Medicine.,3 Academic Affairs, and.,4 Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, Colorado; and
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Gahring LC, Myers EJ, Dunn DM, Weiss RB, Rogers SW. Nicotinic alpha 7 receptor expression and modulation of the lung epithelial response to lipopolysaccharide. PLoS One 2017; 12:e0175367. [PMID: 28384302 PMCID: PMC5383308 DOI: 10.1371/journal.pone.0175367] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/26/2017] [Indexed: 01/14/2023] Open
Abstract
Nicotine modulates multiple inflammatory responses in the lung through the nicotinic acetylcholine receptor subtype alpha7 (α7). Previously we reported that α7 modulates both the hematopoietic and epithelium responses in the lung to the bacterial inflammogen, lipopolysaccharide (LPS). Here we apply immunohistochemistry, flow cytometry and RNA-Seq analysis of isolated distal lung epithelium to further define α7-expression and function in this tissue. Mouse lines were used that co-express a bicistronic tau-green fluorescent protein (tGFP) as a reporter of α7 (α7G) expression and that harbor an α7 with a specific point mutation (α7E260A:G) that selectively uncouples it from cell calcium-signaling mechanisms. The tGFP reporter reveals strong cell-specific α7-expression by alveolar macrophages (AM), Club cells and ATII cells. Ciliated cells do not express detectible tGFP, but their numbers decrease by one-third in the α7E260A:G lung compared to controls. Transcriptional comparisons (RNA-Seq) between α7G and α7E260A:G enriched lung epithelium 24 hours after challenge with either intra-nasal (i.n.) saline or LPS reveals a robust α7-genotype impact on both the stasis and inflammatory response of this tissue. Overall the α7E260A:G lung epithelium exhibits reduced inflammatory cytokine/chemokine expression to i.n. LPS. Transcripts specific to Club cells (e.g., CC10, secretoglobins and Muc5b) or to ATII cells (e.g., surfactant proteins) were constitutively decreased in in the α7E260A:G lung, but they were strongly induced in response to i.n. LPS. Protein analysis applying immunohistochemistry and ELISA also revealed α7-associated differences suggested by RNA-Seq including altered mucin protein 5b (Muc5b) accumulation in the α7E260A:G bronchia, that in some cases appeared to form airway plugs, and a substantial increase in extracellular matrix deposits around α7E260A:G airway bronchia linings that was not seen in controls. Our results show that α7 is an important modulator of normal gene expression stasis and the response to an inhaled inflammogen in the distal lung epithelium. Further, when normal α7 signaling is disrupted, changes in lung gene expression resemble those associated with long-term lung pathologies seen in humans who use inhaled nicotine products.
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Affiliation(s)
- Lorise C. Gahring
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Administration Medical Center, Salt Lake City, Utah, United States of America
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail: (LCG); (SWR)
| | - Elizabeth J. Myers
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Diane M. Dunn
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Robert B. Weiss
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Scott W. Rogers
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Administration Medical Center, Salt Lake City, Utah, United States of America
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail: (LCG); (SWR)
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St-Pierre S, Jiang W, Roy P, Champigny C, LeBlanc É, Morley BJ, Hao J, Simard AR. Nicotinic Acetylcholine Receptors Modulate Bone Marrow-Derived Pro-Inflammatory Monocyte Production and Survival. PLoS One 2016; 11:e0150230. [PMID: 26925951 PMCID: PMC4771711 DOI: 10.1371/journal.pone.0150230] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/10/2016] [Indexed: 12/24/2022] Open
Abstract
It is increasingly clear that nicotinic acetylcholine receptors (nAChRs) are involved in immune regulation, and that their activation can protect against inflammatory diseases. Previous data have shown that nicotine diminishes the numbers of peripheral monocytes and macrophages, especially those of the pro-inflammatory phenotype. The goal of the present study was to determine if nicotine modulates the production of bone marrow -derived monocytes/macrophages. In this study, we first found that murine bone marrow cells express multiple nAChR subunits, and that the α7 and α9 nAChRs most predominant subtypes found in immune cells and their precursors. Using primary cultures of murine bone marrow cells, we then determined the effect of nicotine on monocyte colony-stimulating factor and interferon gamma (IFNγ)-induced monocyte production. We found that nicotine lowered the overall number of monocytes, and more specifically, inhibited the IFNγ-induced increase in pro-inflammatory monocytes by reducing cell proliferation and viability. These data suggested that nicotine diminishes the ratio of pro-inflammatory versus anti-inflammatory monocyte produced in the bone marrow. We thus confirmed this hypothesis by measuring cytokine expression, where we found that nicotine inhibited the production of the pro-inflammatory cytokines TNFα, IL-1β and IL-12, while stimulating the secretion of IL-10, an anti-inflammatory cytokine. Finally, nicotine also reduced the number of pro-inflammatory monocytes in the bone marrow of LPS-challenged mice. Overall, our data demonstrate that both α7 and α9 nAChRs are involved in the regulation of pro-inflammatory M1 monocyte numbers.
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Affiliation(s)
- Stéphanie St-Pierre
- Département de Chimie et Biochimie, Université de Moncton, Moncton, NB, Canada
| | - Wei Jiang
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Patrick Roy
- Département de Chimie et Biochimie, Université de Moncton, Moncton, NB, Canada
| | - Camille Champigny
- Centre de Formation Médicale du Nouveau-Brunswick, Moncton, NB, Canada
| | - Éric LeBlanc
- Département de Chimie et Biochimie, Université de Moncton, Moncton, NB, Canada
| | - Barbara J. Morley
- Boys Town National Research Hospital, Omaha, NE, United States of America
| | - Junwei Hao
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Alain R. Simard
- Département de Chimie et Biochimie, Université de Moncton, Moncton, NB, Canada
- Centre de Formation Médicale du Nouveau-Brunswick, Moncton, NB, Canada
- * E-mail:
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15
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Egea J, Buendia I, Parada E, Navarro E, León R, Lopez MG. Anti-inflammatory role of microglial alpha7 nAChRs and its role in neuroprotection. Biochem Pharmacol 2015; 97:463-72. [DOI: 10.1016/j.bcp.2015.07.032] [Citation(s) in RCA: 209] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/27/2015] [Indexed: 12/15/2022]
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16
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Minami SS, Shen V, Le D, Krabbe G, Asgarov R, Perez-Celajes L, Lee CH, Li J, Donnelly-Roberts D, Gan L. Reducing inflammation and rescuing FTD-related behavioral deficits in progranulin-deficient mice with α7 nicotinic acetylcholine receptor agonists. Biochem Pharmacol 2015. [PMID: 26206194 DOI: 10.1016/j.bcp.2015.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mutations in the progranulin gene cause frontotemporal dementia (FTD), a debilitating neurodegenerative disease that involves atrophy of the frontal and temporal lobes and affects personality, behavior, and language. Progranulin-deficient mouse models of FTD exhibit deficits in compulsive and social behaviors reminiscent of patients with FTD, and develop excessive microgliosis and increased release of inflammatory cytokines. Activation of nicotinic acetylcholine receptors (nAChRs) by nicotine or specific α7 nAChR agonists reduces neuroinflammation. Here, we investigated whether activation of nAChRs by nicotine or α7 agonists improved the excessive inflammatory and behavioral phenotypes of a progranulin-deficient FTD mouse model. We found that treatment with selective α7 agonists, PHA-568487 or ABT-107, strongly suppressed the activation of NF-κB in progranulin-deficient cells. Treatment with ABT-107 also reduced microgliosis, decreased TNFα levels, and reduced compulsive behavior in progranulin-deficient mice. Collectively, these data suggest that targeting activation of the α7 nAChR pathway may be beneficial in decreasing neuroinflammation and reversing some of the behavioral deficits observed in progranulin-deficient FTD.
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Affiliation(s)
- S Sakura Minami
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States; Department of Neurology, University of California, San Francisco, CA 94158, United States
| | - Vivian Shen
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States
| | - David Le
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States
| | - Grietje Krabbe
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States; Department of Neurology, University of California, San Francisco, CA 94158, United States
| | - Rustam Asgarov
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States; Graduate Program in Neurochemistry and Molecular Neurobiology, Stockholm University, Sweden
| | - Liberty Perez-Celajes
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States
| | | | - Jinhe Li
- AbbVie Inc., North Chicago, IL 60064, United States
| | | | - Li Gan
- Gladstone Institute of Neurological Diseases, 1650 Owens St., San Francisco, CA 94158, United States; Department of Neurology, University of California, San Francisco, CA 94158, United States.
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17
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Lykhmus O, Gergalova G, Zouridakis M, Tzartos S, Komisarenko S, Skok M. Inflammation decreases the level of alpha7 nicotinic acetylcholine receptors in the brain mitochondria and makes them more susceptible to apoptosis induction. Int Immunopharmacol 2015; 29:148-51. [PMID: 25887272 DOI: 10.1016/j.intimp.2015.04.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/06/2015] [Accepted: 04/01/2015] [Indexed: 12/11/2022]
Abstract
α7 nicotinic acetylcholine receptors (α7 nAChRs) are involved in regulating inflammatory reactions, as well as the cell viability. They are expressed in both the plasma membrane and mitochondria of eukaryotic cells. Previously we found that neuroinflammation resulted in the decrease of α7 nAChR density in the brain of mice and was accompanied by accumulation of amyloid-beta (Aβ) peptides and memory impairment. In the present paper, it is shown that inflammation induced by either regular bacterial lipopolysaccharide (LPS) injections or immunizations with α7 nAChR extracellular domain (1-208) affected also the brain cell mitochondria. Using various modifications of sandwich ELISA, we observed the decrease of α7 nAChRs and accumulation of Aβ(1-40) and Aβ(1-42) in mitochondria of immunized or LPS-treated mice compared to control ones. Mitochondria of treated mice responded with cytochrome c release to lower Ca(2+) concentrations than mitochondria of control mice and were less sensitive to its attenuation with α7 nAChR agonist PNU282987. It is concluded that inflammation decreases α7 nAChR expression in both mitochondria and cell plasma membrane and makes mitochondria more susceptible to apoptosis induction.
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Affiliation(s)
| | | | | | | | | | - Maryna Skok
- Palladin Institute of Biochemistry, Kyiv, Ukraine.
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18
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Enioutina EY, Myers EJ, Tvrdik P, Hoidal JR, Rogers SW, Gahring LC. The nicotinic receptor Alpha7 impacts the mouse lung response to LPS through multiple mechanisms. PLoS One 2015; 10:e0121128. [PMID: 25803612 DOI: 10.1371/journal.pone.0121128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/28/2015] [Indexed: 01/09/2023] Open
Abstract
The nicotinic acetylcholine receptor alpha7 (α7) is expressed by neuronal and non-neuronal cells throughout the body. We examined the mechanisms of the lung inflammatory response to intranasal (i.n.) lipopolysaccharide (LPS) regulated by α7. This was done in mice using homologous recombination to introduce a point mutation in the α7 receptor that replaces the glutamate residue 260 that lines the pore with alanine (α7E260A), which has been implicated in controlling the exceptional calcium ion conductance of this receptor. The α7E260A mice exhibit normal inflammatory cell recruitment to the blood in response to i.n. LPS administration. This differs from the α7knock-out (α7KO) in which upstream signaling to initiate the recruitment to the blood following i.n. LPS is significantly impaired. While hematopoietic cells are recruited to the bloodstream in the α7E260A mouse, they fail to be recruited efficiently into both the interstitium and alveolar spaces of the lung. Bone marrow reconstitution experiments demonstrate that the responsiveness of both CD45+ and CD45- cells of the α7E260A mouse are impaired. The expression of several pro-inflammatory cytokine and chemokine RNAs including TNFα, IL-1α, Ccl2 and Cxcl10 are decreased in the α7E260A mouse. However, there is a substantial increase in IL-13 expression by CD45- lung interstitial cells in the α7E260A mouse. Our results support the conclusion that α7 functional pleiotropy contributes to modulating the tissue response to an inflammatory insult through impacting upon a variety of mechanisms reflecting the individual cell composition of the lung.
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Dineley KT, Pandya AA, Yakel JL. Nicotinic ACh receptors as therapeutic targets in CNS disorders. Trends Pharmacol Sci 2015; 36:96-108. [PMID: 25639674 PMCID: PMC4324614 DOI: 10.1016/j.tips.2014.12.002] [Citation(s) in RCA: 329] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 01/30/2023]
Abstract
The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor (nAChR) channels. These receptors are widely distributed throughout the central nervous system (CNS), being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however, the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer's disease, AD), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain.
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Affiliation(s)
- Kelly T Dineley
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch at Galveston (UTMB), Galveston, TX, USA
| | - Anshul A Pandya
- Chukchi Campus, Department of Bioscience, College of Rural and Community Development, University of Alaska Fairbanks, P.O. Box 297, Kotzebue, AK 99752-0297, USA
| | - Jerrel L Yakel
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health (NIEHS/NIH), Department of Health and Human Services (DHHS), F2-08, P.O. Box 12233, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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Abstract
The nicotinic acetylcholine receptor alpha 7 (α7) is a ligand-activated ion channel that contributes to a diversity of cellular processes involved in development, neurotransmission and inflammation. In this report the expression of α7 was examined in the mouse developing and adult adrenal gland that expresses a green fluorescent protein (GFP) reporter as a bi-cistronic extension of the endogenous α7 transcript (α7(G)). At embryonic day 12.5 (E12.5) α7(G) expression was associated with the suprarenal ganglion and precursor cells of the adrenal gland. The α7(G) cells are catecholaminergic chromaffin cells as reflected by their progressive increase in the co-expression of tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) that is complete by E18.5. In the adult, α7(G) expression is limited to a subset of chromaffin cells in the adrenal medulla that cluster near the border with the adrenal cortex. These chromaffin cells co-express α7(G), TH and DBH, but they lack phenylethanolamine N-methyltransferase (PNMT) consistent with only norepinephrine (NE) synthesis. These cell groups appear to be preferentially innervated by pre-ganglionic afferents identified by the neurotrophin receptor p75. No afferents identified by beta-III tubulin, neurofilament proteins or p75 co-expressed α7(G). Occasional α7(G) cells in the pre-E14.5 embryos express neuronal markers consistent with intrinsic ganglion cells and in the adult some α7(G) cells co-express glutamic acid decarboxylase. The transient expression of α7 during adrenal gland development and its prominent co-expression by a subset of NE chromaffin cells in the adult suggests that the α7 receptor contributes to multiple aspects of adrenal gland development and function that persist into adulthood.
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Affiliation(s)
- Lorise C. Gahring
- Salt Lake City VA Geriatric Research, Education and Clinical Center, Salt Lake City, Utah, United States of America
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States of America
| | - Elizabeth Myers
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States of America
| | - Sierra Palumbos
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - Scott W. Rogers
- Salt Lake City VA Geriatric Research, Education and Clinical Center, Salt Lake City, Utah, United States of America
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
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Wu H, Li L, Su X. Vagus nerve through α7 nAChR modulates lung infection and inflammation: models, cells, and signals. Biomed Res Int 2014; 2014:283525. [PMID: 25136575 DOI: 10.1155/2014/283525] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/08/2014] [Accepted: 05/15/2014] [Indexed: 12/27/2022]
Abstract
Cholinergic anti-inflammatory pathway (CAP) bridges immune and nervous systems and plays pleiotropic roles in modulating inflammation in animal models by targeting different immune, proinflammatory, epithelial, endothelial, stem, and progenitor cells and signaling pathways. Acute lung injury (ALI) is a devastating inflammatory disease. It is pathogenically heterogeneous and involves many cells and signaling pathways. Here, we emphasized the research regarding the modulatory effects of CAP on animal models, cell population, and signaling pathways that involved in the pathogenesis of ALI. By comparing the differential effects of CAP on systemic and pulmonary inflammation, we postulated that a pulmonary parasympathetic inflammatory reflex is formed to sense and respond to pathogens in the lung. Work targeting the formation and function of pulmonary parasympathetic inflammatory reflex would extend our understanding of how vagus nerve senses, recognizes, and fights with pathogens and inflammatory responses.
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Abstract
Processing of sensory information is substantially shaped by centrifugal, or feedback, projections from higher cortical areas, yet the functional properties of these projections are poorly characterized. Here, we used genetically-encoded calcium sensors (GCaMPs) to functionally image activation of centrifugal projections targeting the olfactory bulb (OB). The OB receives massive centrifugal input from cortical areas but there has been as yet no characterization of their activity in vivo. We focused on projections to the OB from the anterior olfactory nucleus (AON), a major source of cortical feedback to the OB. We expressed GCaMP selectively in AON projection neurons using a mouse line expressing Cre recombinase (Cre) in these neurons and Cre-dependent viral vectors injected into AON, allowing us to image GCaMP fluorescence signals from their axon terminals in the OB. Electrical stimulation of AON evoked large fluorescence signals that could be imaged from the dorsal OB surface in vivo. Surprisingly, odorants also evoked large signals that were transient and coupled to odorant inhalation both in the anesthetized and awake mouse, suggesting that feedback from AON to the OB is rapid and robust across different brain states. The strength of AON feedback signals increased during wakefulness, suggesting a state-dependent modulation of cortical feedback to the OB. Two-photon GCaMP imaging revealed that different odorants activated different subsets of centrifugal AON axons and could elicit both excitation and suppression in different axons, indicating a surprising richness in the representation of odor information by cortical feedback to the OB. Finally, we found that activating neuromodulatory centers such as basal forebrain drove AON inputs to the OB independent of odorant stimulation. Our results point to the AON as a multifunctional cortical area that provides ongoing feedback to the OB and also serves as a descending relay for other neuromodulatory systems.
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Affiliation(s)
- Markus Rothermel
- Brain Institute and Department of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
| | - Matt Wachowiak
- Brain Institute and Department of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
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23
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Abstract
Acetylcholine (ACh) can regulate neuronal excitability in the hippocampus, an important area in the brain for learning and memory, by acting on both nicotinic (nAChRs) and muscarinic ACh receptors. The primary cholinergic input to the hippocampus arises from the medial septum and diagonal band of Broca (MS-DBB), and we investigated how their activation regulated hippocampal synaptic plasticity. We found that activation of these endogenous cholinergic inputs can directly induce different forms of hippocampal synaptic plasticity with a timing precision in the millisecond range. Furthermore, we observed a prolonged enhancement of excitability both pre- and postsynaptically. Lastly we found that the presence of the α7 nAChR subtype to both pre- and postsynaptic sites appeared to be required to induce this plasticity. We propose that α7 nAChRs coordinate pre- and postsynaptic activities to induce glutamatergic synaptic plasticity, and thus provide a novel mechanism underlying physiological neuronal communication that could lead to timing-dependent synaptic plasticity in the hippocampus.
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Affiliation(s)
- Jerrel L Yakel
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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