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Pakai E, Tekus V, Zsiboras C, Rumbus Z, Olah E, Keringer P, Khidhir N, Matics R, Deres L, Ordog K, Szentes N, Pohoczky K, Kemeny A, Hegyi P, Pinter E, Garami A. The Neurokinin-1 Receptor Contributes to the Early Phase of Lipopolysaccharide-Induced Fever via Stimulation of Peripheral Cyclooxygenase-2 Protein Expression in Mice. Front Immunol 2018; 9:166. [PMID: 29459872 PMCID: PMC5807668 DOI: 10.3389/fimmu.2018.00166] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 11/17/2017] [Accepted: 01/18/2018] [Indexed: 12/20/2022] Open
Abstract
Neurokinin (NK) signaling is involved in various inflammatory processes. A common manifestation of systemic inflammation is fever, which is usually induced in animal models with the administration of bacterial lipopolysaccharide (LPS). A role for the NK1 receptor was shown in LPS-induced fever, but the underlying mechanisms of how the NK1 receptor contributes to febrile response, especially in the early phase, have remained unknown. We administered LPS (120 µg/kg, intraperitoneally) to mice with the Tacr1 gene, i.e., the gene encoding the NK1 receptor, either present (Tacr1+/+ ) or absent (Tacr1-/- ) and measured their thermoregulatory responses, serum cytokine levels, tissue cyclooxygenase-2 (COX-2) expression, and prostaglandin (PG) E2 concentration. We found that the LPS-induced febrile response was attenuated in Tacr1-/- compared to their Tacr1+/+ littermates starting from 40 min postinfusion. The febrigenic effect of intracerebroventricularly administered PGE2 was not suppressed in the Tacr1-/- mice. Serum concentration of pyrogenic cytokines did not differ between Tacr1-/- and Tacr1+/+ at 40 min post-LPS infusion. Administration of LPS resulted in amplification of COX-2 mRNA expression in the lungs, liver, and brain of the mice, which was statistically indistinguishable between the genotypes. In contrast, the LPS-induced augmentation of COX-2 protein expression was attenuated in the lungs and tended to be suppressed in the liver of Tacr1-/- mice compared with Tacr1+/+ mice. The Tacr1+/+ mice responded to LPS with a significant surge of PGE2 production in the lungs, whereas Tacr1-/- mice did not. In conclusion, the NK1 receptor is necessary for normal fever genesis. Our results suggest that the NK1 receptor contributes to the early phase of LPS-induced fever by enhancing COX-2 protein expression in the periphery. These findings advance the understanding of the crosstalk between NK signaling and the "cytokine-COX-2-prostaglandin E2" axis in systemic inflammation, thereby open up the possibilities for new therapeutic approaches.
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Affiliation(s)
- Eszter Pakai
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary.,Momentum Gastroenterology Multidisciplinary Research Group, Hungarian Academy of Sciences - University of Szeged, Szeged, Hungary
| | - Valeria Tekus
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Csaba Zsiboras
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Zoltan Rumbus
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Emoke Olah
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Patrik Keringer
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Nora Khidhir
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Robert Matics
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Laszlo Deres
- Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,First Department of Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Katalin Ordog
- Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,First Department of Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Nikolett Szentes
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Krisztina Pohoczky
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Agnes Kemeny
- Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,Department of Medical Biology, Medical School, University of Pecs, Pecs, Hungary
| | - Peter Hegyi
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary.,Momentum Gastroenterology Multidisciplinary Research Group, Hungarian Academy of Sciences - University of Szeged, Szeged, Hungary.,First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Erika Pinter
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pecs, Pecs, Hungary.,Janos Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Andras Garami
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
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Suvas S. Role of Substance P Neuropeptide in Inflammation, Wound Healing, and Tissue Homeostasis. J Immunol 2017; 199:1543-1552. [PMID: 28827386 DOI: 10.4049/jimmunol.1601751] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 06/13/2017] [Indexed: 11/19/2022]
Abstract
Substance P (SP) is an undecapeptide present in the CNS and the peripheral nervous system. SP released from the peripheral nerves exerts its biological and immunological activity via high-affinity neurokinin 1 receptor (NK1R). SP is also produced by immune cells and acts as an autocrine or paracrine fashion to regulate the function of immune cells. In addition to its proinflammatory role, SP and its metabolites in combination with insulin-like growth factor-1 are shown to promote the corneal epithelial wound healing. Recently, we showed an altered ocular surface homeostasis in unmanipulated NK1R-/- mice, suggesting the role of SP-NK1R signaling in ocular surface homeostasis under steady-state. This review summarizes the immunobiology of SP and its effect on immune cells and immunity to microbial infection. In addition, the effect of SP in inflammation, wound healing, and corneal epithelial homeostasis in the eye is discussed.
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Affiliation(s)
- Susmit Suvas
- Department of Ophthalmology/Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI 48201; .,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201; and .,Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201
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3
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Rodgers J, Bradley B, Kennedy PGE. Delineating neuroinflammation, parasite CNS invasion, and blood-brain barrier dysfunction in an experimental murine model of human African trypanosomiasis. Methods 2017. [PMID: 28636879 PMCID: PMC5595161 DOI: 10.1016/j.ymeth.2017.06.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [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] [Indexed: 12/22/2022] Open
Abstract
Although Trypanosoma brucei spp. was first detected by Aldo Castellani in CSF samples taken from sleeping sickness patients over a century ago there is still a great deal of debate surrounding the timing, route and effects of transmigration of the parasite from the blood to the CNS. In this investigation, we have applied contrast-enhance magnetic resonance imaging (MRI) to study the effects of trypanosome infection on the blood-brain barrier (BBB) in the well-established GVR35 mouse model of sleeping sickness. In addition, we have measured the trypanosome load present in the brain using quantitative Taqman PCR and assessed the severity of the neuroinflammatory reaction at specific time points over the course of the infection. Contrast enhanced-MRI detected a significant degree of BBB impairment in mice at 14days following trypanosome infection, which increased in a step-wise fashion as the disease progressed. Parasite DNA was present in the brain tissue on day 7 after infection. This increased significantly in quantity by day 14 post-infection and continued to rise as the infection advanced. A progressive increase in neuroinflammation was detected following trypanosome infection, reaching a significant level of severity on day 14 post-infection and rising further at later time-points. In this model stage-2 disease presents at 21days post-infection. The combination of the three methodologies indicates that changes in the CNS become apparent prior to the onset of established stage-2 disease. This could in part account for the difficulties associated with defining specific criteria to distinguish stage-1 and stage-2 infections and highlights the need for improved staging diagnostics.
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Affiliation(s)
- Jean Rodgers
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G61 1QH, UK.
| | - Barbara Bradley
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G61 1QH, UK
| | - Peter G E Kennedy
- Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G61 1QH, UK
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Martinez AN, Philipp MT. Substance P and Antagonists of the Neurokinin-1 Receptor in Neuroinflammation Associated with Infectious and Neurodegenerative Diseases of the Central Nervous System. ACTA ACUST UNITED AC 2016; 1:29-36. [PMID: 27430034 DOI: 10.29245/2572.942x/2016/2.1020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [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: 12/23/2022]
Abstract
This review addresses the role that substance P (SP) and its preferred receptor neurokinin-1 (NK1R) play in neuroinflammation associated with select bacterial, viral, parasitic, and neurodegenerative diseases of the central nervous system. The SP/NK1R complex is a key player in the interaction between the immune and nervous systems. A common effect of this interaction is inflammation. For this reason and because of the predominance in the human brain of the NK1R, its antagonists are attractive potential therapeutic agents. Preventing the deleterious effects of SP through the use of NK1R antagonists has been shown to be a promising therapeutic strategy, as these antagonists are selective, potent, and safe. Here we evaluate their utility in the treatment of different neuroinfectious and neuroinflammatory diseases, as a novel approach to clinical management of CNS inflammation.
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Affiliation(s)
- Alejandra N Martinez
- Division of Bacteriology & Parasitology, Tulane National Primate Research Center, Covington, LA, USA
| | - Mario T Philipp
- Division of Bacteriology & Parasitology, Tulane National Primate Research Center, Covington, LA, USA; Department of Microbiology and Immunology, Tulane University Medical School, New Orleans, LA, USA
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Rodgers J, Bradley B, Kennedy PGE, Sternberg JM. Central Nervous System Parasitosis and Neuroinflammation Ameliorated by Systemic IL-10 Administration in Trypanosoma brucei-Infected Mice. PLoS Negl Trop Dis 2015; 9:e0004201. [PMID: 26505761 PMCID: PMC4624684 DOI: 10.1371/journal.pntd.0004201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/08/2015] [Indexed: 02/01/2023] Open
Abstract
Invasion of the central nervous system (CNS) by African trypanosomes represents a critical step in the development of human African trypanosomiasis. In both clinical cases and experimental mouse infections it has been demonstrated that predisposition to CNS invasion is associated with a type 1 systemic inflammatory response. Using the Trypanosoma brucei brucei GVR35 experimental infection model, we demonstrate that systemic delivery of the counter-inflammatory cytokine IL-10 lowers plasma IFN-γ and TNF-α concentrations, CNS parasitosis and ameliorates neuro-inflammatory pathology and clinical symptoms of disease. The results provide evidence that CNS invasion may be susceptible to immunological attenuation.
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Affiliation(s)
- Jean Rodgers
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Barbara Bradley
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Peter G E Kennedy
- Department of Neurology, Institute of Neurological Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Jeremy M Sternberg
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
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6
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Institute of Neurological Sciences, College of Medicine, Veterinary and Life Sciences, Glasgow University, Southern General Hospital, Glasgow, United Kingdom
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7
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Weinstock JV. Substance P and the regulation of inflammation in infections and inflammatory bowel disease. Acta Physiol (Oxf) 2015; 213:453-61. [PMID: 25424746 DOI: 10.1111/apha.12428] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/07/2014] [Accepted: 11/17/2014] [Indexed: 12/16/2022]
Abstract
Substance P (SP) and its natural analogue hemokinin-1 (HK1) are produced by lymphocytes and macrophages, and at times B cells. These peptides are an important component of the immune response during several infections and in inflammatory bowel disease (IBD). The synthesis of SP and HK1 in leucocytes is subject to immune regulation. IL12 and IL23 stimulate T cells and macrophages to make SP respectively. The cytokines driving HK1 production are not presently defined. These peptides act through a shared receptor called neurokinin-1. T cells, macrophages and probably other immune cell types can express this receptor. Several cytokines IL12, IL18 and TNFα as well as T-cell antigen receptor activation induce neurokinin-1 receptor expression on T cells, while IL10 blocks receptor display. TGFβ delays internalization of the SP/neurokine-1R complex on T cells resulting in stronger receptor signalling. One of the functions of SP and neurokinin-1 receptor is to enhance T cell IFNγ and IL17 production, amplifying the proinflammatory response. Thus, SP and HK1 have overlapping functions and are part of a sophisticated immune regulatory circuit aimed at amplifying inflammation at mucosal surfaces and in other regions of the body as shown in animal models of infection and IBD.
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Affiliation(s)
- J. V. Weinstock
- Division of Gastroenterology; Tufts Medical Center; Boston MA USA
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Abstract
Apoptosis, or programmed cell death, is a fundamental and widespread cell biological process that is distinct from cell necrosis and can be induced by a wide variety of stimuli including viral infections. Apoptosis may occur via either the intrinsic or extrinsic pathways and confers several advantages to the virally infected host including the prevention of further viral propagation and the potential inhibition and resolution of inflammatory processes. Several viruses have been shown to have the capacity to induce apoptosis in susceptible cells including herpes simplex virus, Varicella-zoster virus, rabies virus, human immunodeficiency virus, and reovirus. Apoptosis has also been observed in human African trypanosomiasis which is an infection caused by a protozoan parasite. The mechanisms leading to apoptosis may differ depending on the type of infection. Apoptosis has been reported in several neurodegenerative diseases and also psychiatric disorders but the true clinical significance of such observations is not certain, and, though interesting, it is very difficult to ascribe causation in these conditions. The presence of inflammation in the central nervous system in any neurological condition, including those associated with a viral infection, is not necessarily an absolute marker of serious disease and the notion of 'good' versus 'bad' inflammation is considered to be valid in some circumstances. The precise relationship between viruses, apoptosis, and inflammation is viewed as a complex one requiring further investigation to unravel and understand its nature.
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow University, Glasgow, G51 4TF, Scotland, UK,
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Wang Q, Chu CH, Qian L, Chen SH, Wilson B, Oyarzabal E, Jiang L, Ali S, Robinson B, Kim HC, Hong JS. Substance P exacerbates dopaminergic neurodegeneration through neurokinin-1 receptor-independent activation of microglial NADPH oxidase. J Neurosci 2014; 34:12490-503. [PMID: 25209287 DOI: 10.1523/JNEUROSCI.2238-14.2014] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Although dysregulated substance P (SP) has been implicated in the pathophysiology of Parkinson's disease (PD), how SP affects the survival of dopaminergic neurons remains unclear. Here, we found that mice lacking endogenous SP (TAC1(-/-)), but not those deficient in the SP receptor (neurokinin-1 receptor, NK1R), were more resistant to lipopolysaccharide (LPS)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigral dopaminergic neurodegeneration than wild-type controls, suggesting a NK1R-independent toxic action of SP. In vitro dose-response studies revealed that exogenous SP enhanced LPS- and 1-methyl-4-phenylpyridinium (MPP(+))-induced dopaminergic neurodegeneration in a bimodal manner, peaking at submicromolar and subpicomolar concentrations, but was substantially less effective at intermediate concentrations. Mechanistically, the actions of submicromolar levels of SP were NK1R-dependent, whereas subpicomolar SP-elicited actions required microglial NADPH oxidase (NOX2), the key superoxide-producing enzyme, but not NK1R. Subpicomolar concentrations of SP activated NOX2 by binding to the catalytic subunit gp91(phox) and inducing membrane translocation of the cytosolic subunits p47(phox) and p67(phox). The importance of NOX2 was further corroborated by showing that inhibition or disruption of NOX2 blocked subpicomolar SP-exacerbated neurotoxicity. Together, our findings revealed a critical role of microglial NOX2 in mediating the neuroinflammatory and dopaminergic neurodegenerative effects of SP, which may provide new insights into the pathogenesis of PD.
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Nasimolo J, Kiama SG, Gathumbi PK, Makanya AN, Kagira JM. Erythrina abyssinica prevents meningoencephalitis in chronic Trypanosoma brucei brucei mouse model. Metab Brain Dis 2014; 29:509-19. [PMID: 24452611 DOI: 10.1007/s11011-014-9488-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Human African trypanosomiasis is prevalent in Sub-sahara African countries that lie between 14° North and 29° south of the equator. Sixty million people are at risk of infection. Trypanosoma brucei gambesience occurs in West and Central Africa while Trypanosoma brucei rhodesience occurs in East and Southern Africa. The neurological stage of the disease is characterized by neuroinflammation. About 10% of patients treated with the recommended drug, melarsoprol develop post treatment reactive encephalopathy, which is fatal in 50% of these patients, thus melarsoprol is fatal in 5% of all treated patients. This study was aimed at establishing the potential activity of Erythrina abyssinica in reducing neuroinflammation following infection with Trypanosoma brucei brucei. Swiss white mice were divided into ten groups, two control groups and eight infected groups. Infected mice received either methanol or water extract of Erythrina abyssinica at 12.5, 25, 50 or 100 mg/kg body weight. Parasite counts were monitored in peripheral circulation from the third day post infection up to the end of the study. Brains were processed for histology, immunohistochemistry scanning and transmission electron microscopy. Following infection, trypanosomes were observed in circulation 3 days post-infection, with the parasitaemia occurring in waves. In the cerebrum, typical brain pathology of chronic trypanosomiasis was reproduced. This was exhibited as astrocytosis, perivascular cuffing and infiltration of inflammatory cells into the neuropil. However, mice treated with Erythrina abyssinica water extract exhibited significant reduction in perivascular cuffing, lymphocytic infiltration and astrocytosis in the cerebrum. The methanol extract did not have a significant difference compared to the non-treated group. This study provides evidence of anti-inflammatory properties of Erythrina abyssinica and may support its wide use as a medicinal plant by various communities in Kenya.
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Affiliation(s)
- Johnson Nasimolo
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya,
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11
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Bentivoglio M, Kristensson K. Tryps and trips: cell trafficking across the 100-year-old blood-brain barrier. Trends Neurosci 2014; 37:325-33. [PMID: 24780507 DOI: 10.1016/j.tins.2014.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [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] [Received: 01/03/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 01/03/2023]
Abstract
The blood–brain barrier (BBB) was discovered one century ago by the use of trypan dyes. The discovery initiated the targeted brain delivery of drugs. Trypan dyes were developed to kill African trypanosomes that cause sleeping sickness. Trypanosomes disclose cell trafficking in and out of the BBB. Disturbed gating at the BBB may cause neurodegeneration.
One hundred years ago, Edwin E. Goldmann discovered the blood–brain barrier (BBB) using trypan dyes. These dyes were developed and named by Paul Ehrlich during his search for drugs to kill African trypanosomes (extracellular parasites that cause sleeping sickness) while sparing host cells. For Ehrlich, this was the first strategy based on the ‘chemotherapy’ concept he had introduced. The discovery of the BBB revealed, however, the difficulties in drug delivery to the brain. Mechanisms by which parasites enter, dwell, and exit the brain currently provide novel views on cell trafficking across the BBB. These mechanisms also highlight the role of pericytes and endocytosis regulation in BBB functioning and in disrupted BBB gating, which may be involved in the pathogenesis of neurodegeneration.
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Spitsin S, Stevens KE, Douglas SD. Expression of substance P, neurokinin-1 receptor and immune markers in the brains of individuals with HIV-associated neuropathology. J Neurol Sci 2013; 334:18-23. [PMID: 23916293 DOI: 10.1016/j.jns.2013.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/09/2013] [Accepted: 07/11/2013] [Indexed: 10/26/2022]
Abstract
The tachykinin neuropeptide substance P (SP) has an important signaling role in both the nervous and the immune systems. Two naturally occurring variants of the neurokinin-1 receptor (NK1R) mediate the effects of SP, full-length receptor (NK1R-F) and a truncated form (NK1R-T) that lacks 96 amino acid residues at the C-terminus. We previously reported decreased expression of the NK1R-F in the CNS of HIV-positive individuals in comparison to HIV-negative control subjects. There were no differences in the expression of the NK1R-T in the same groups. In the current study, we quantified the expressions of SP precursor mRNA preprotachykinin (TAC1), NK1R (full and truncated forms), viral load (HIV-gag) and several proinflammatory and immune markers (CD4, CCR5, CXCR4, fractalkine, IL-6, IL-10, CCL2, CCL20 and CD163) in the frontal cortex of autopsied brains from HIV-1-positive individuals with or without HIV-associated neuropathology. The expressions of SP and, to lesser extent, NK1R-F were decreased while the expressions of CXCR4, CCR5 and CCL2 were increased in CNS of individuals with HIV-associated neuropathology. There was no change in HIV loads associated with neuropathology; however, we found a positive correlation between viral loads and the expression of haptoglobin-hemoglobin scavenger receptor CD163. An analysis of CSF from corresponding samples demonstrated an increase in proinflammatory markers (CCL2 MIP-1α and MIP-1β) associated with neuropathology. Although our data confirm the overall inflammatory nature of HIV-associated neuropathology, we observed a decrease in the expression of SP and NK1R-F, which is also associated with other forms of neuroinflammation.
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Affiliation(s)
- Sergei Spitsin
- Division of Allergy and Immunology, Research Institute, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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Frevert U, Movila A, Nikolskaia OV, Raper J, Mackey ZB, Abdulla M, McKerrow J, Grab DJ. Early invasion of brain parenchyma by African trypanosomes. PLoS One 2012; 7:e43913. [PMID: 22952808 PMCID: PMC3432051 DOI: 10.1371/journal.pone.0043913] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [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: 05/01/2012] [Accepted: 07/26/2012] [Indexed: 12/11/2022] Open
Abstract
Human African trypanosomiasis or sleeping sickness is a vector-borne parasitic disease that has a major impact on human health and welfare in sub-Saharan countries. Based mostly on data from animal models, it is currently thought that trypanosome entry into the brain occurs by initial infection of the choroid plexus and the circumventricular organs followed days to weeks later by entry into the brain parenchyma. However, Trypanosoma brucei bloodstream forms rapidly cross human brain microvascular endothelial cells in vitro and appear to be able to enter the murine brain without inflicting cerebral injury. Using a murine model and intravital brain imaging, we show that bloodstream forms of T. b. brucei and T. b. rhodesiense enter the brain parenchyma within hours, before a significant level of microvascular inflammation is detectable. Extravascular bloodstream forms were viable as indicated by motility and cell division, and remained detectable for at least 3 days post infection suggesting the potential for parasite survival in the brain parenchyma. Vascular inflammation, as reflected by leukocyte recruitment and emigration from cortical microvessels, became apparent only with increasing parasitemia at later stages of the infection, but was not associated with neurological signs. Extravascular trypanosomes were predominantly associated with postcapillary venules suggesting that early brain infection occurs by parasite passage across the neuroimmunological blood brain barrier. Thus, trypanosomes can invade the murine brain parenchyma during the early stages of the disease before meningoencephalitis is fully established. Whether individual trypanosomes can act alone or require the interaction from a quorum of parasites remains to be shown. The significance of these findings for disease development is now testable.
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Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Alexandru Movila
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Olga V. Nikolskaia
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jayne Raper
- Department of Biological Sciences, Hunter College of CUNY, New York, New York, United States of America
| | - Zachary B. Mackey
- Department of Pathology, University of California San Francisco, San Francisco, California, United States of America
| | - Maha Abdulla
- Department of Pathology, University of California San Francisco, San Francisco, California, United States of America
| | - James McKerrow
- Department of Pathology, University of California San Francisco, San Francisco, California, United States of America
| | - Dennis J. Grab
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Kitamura H, Kobayashi M, Wakita D, Nishimura T. Neuropeptide signaling activates dendritic cell-mediated type 1 immune responses through neurokinin-2 receptor. J Immunol 2012; 188:4200-8. [PMID: 22474018 DOI: 10.4049/jimmunol.1102521] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neurokinin A (NKA), a neurotransmitter distributed in the central and peripheral nervous system, strictly controls vital responses, such as airway contraction, by intracellular signaling through neurokinin-2 receptor (NK2R). However, the function of NKA-NK2R signaling on involvement in immune responses is less-well defined. We demonstrate that NK2R-mediated neuropeptide signaling activates dendritic cell (DC)-mediated type 1 immune responses. IFN-γ stimulation significantly induced NK2R mRNA and remarkably enhanced surface protein expression levels of bone marrow-derived DCs. In addition, the DC-mediated NKA production level was significantly elevated after IFN-γ stimulation in vivo and in vitro. We found that NKA treatment induced type 1 IFN mRNA expressions in DCs. Transduction of NK2R into DCs augmented the expression level of surface MHC class II and promoted Ag-specific IL-2 production by CD4(+) T cells after NKA stimulation. Furthermore, blockade of NK2R by an antagonist significantly suppressed IFN-γ production by both CD4(+) T and CD8(+) T cells stimulated with the Ag-loaded DCs. Finally, we confirmed that stimulation with IFN-γ or TLR3 ligand (polyinosinic-polycytidylic acid) significantly induced both NK2R mRNA and surface protein expression of human PBMC-derived DCs, as well as enhanced human TAC1 mRNA, which encodes NKA and Substance P. Thus, these findings indicate that NK2R-dependent neuropeptide signaling regulates Ag-specific T cell responses via activation of DC function, suggesting that the NKA-NK2R cascade would be a promising target in chronic inflammation caused by excessive type 1-dominant immunity.
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Affiliation(s)
- Hidemitsu Kitamura
- Division of Immunoregulation, Section of Disease Control, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
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Rodgers J, Jones A, Gibaud S, Bradley B, McCabe C, Barrett MP, Gettinby G, Kennedy PGE. Melarsoprol cyclodextrin inclusion complexes as promising oral candidates for the treatment of human African trypanosomiasis. PLoS Negl Trop Dis 2011; 5:e1308. [PMID: 21909447 PMCID: PMC3167784 DOI: 10.1371/journal.pntd.0001308] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [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: 05/18/2011] [Accepted: 07/23/2011] [Indexed: 12/02/2022] Open
Abstract
Human African trypanosomiasis (HAT), or sleeping sickness, results from infection with the protozoan parasites Trypanosoma brucei (T. b.) gambiense or T. b. rhodesiense and is invariably fatal if untreated. There are 60 million people at risk from the disease throughout sub-Saharan Africa. The infection progresses from the haemolymphatic stage where parasites invade the blood, lymphatics and peripheral organs, to the late encephalitic stage where they enter the central nervous system (CNS) to cause serious neurological disease. The trivalent arsenical drug melarsoprol (Arsobal) is the only currently available treatment for CNS-stage T. b. rhodesiense infection. However, it must be administered intravenously due to the presence of propylene glycol solvent and is associated with numerous adverse reactions. A severe post-treatment reactive encephalopathy occurs in about 10% of treated patients, half of whom die. Thus melarsoprol kills 5% of all patients receiving it. Cyclodextrins have been used to improve the solubility and reduce the toxicity of a wide variety of drugs. We therefore investigated two melarsoprol cyclodextrin inclusion complexes; melarsoprol hydroxypropyl-β-cyclodextrin and melarsoprol randomly-methylated-β-cyclodextrin. We found that these compounds retain trypanocidal properties in vitro and cure CNS-stage murine infections when delivered orally, once per day for 7-days, at a dosage of 0.05 mmol/kg. No overt signs of toxicity were detected. Parasite load within the brain was rapidly reduced following treatment onset and magnetic resonance imaging showed restoration of normal blood-brain barrier integrity on completion of chemotherapy. These findings strongly suggest that complexed melarsoprol could be employed as an oral treatment for CNS-stage HAT, delivering considerable improvements over current parenteral chemotherapy.
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Affiliation(s)
- Jean Rodgers
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Amy Jones
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Stéphane Gibaud
- Laboratoire de Pharmacie Clinique, Nancy Université, Nancy, France
| | - Barbara Bradley
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christopher McCabe
- Institute of Neuroscience and Psychology, Glasgow Experimental MRI Centre, University of Glasgow, Glasgow, United Kingdom
| | - Michael P. Barrett
- Wellcome Trust Centre of Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - George Gettinby
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, United Kingdom
| | - Peter G. E. Kennedy
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Rodgers J, McCabe C, Gettinby G, Bradley B, Condon B, Kennedy PGE. Magnetic resonance imaging to assess blood-brain barrier damage in murine trypanosomiasis. Am J Trop Med Hyg 2011; 84:344-50. [PMID: 21292912 PMCID: PMC3029195 DOI: 10.4269/ajtmh.2011.10-0487] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ability of trypanosomes to invade the brain and induce an inflammatory reaction is well-recognized. This study uses magnetic resonance imaging (MRI) in conjunction with a murine model of central nervous system (CNS) stage trypanosomiasis to investigate this phenomenon at the level of the blood–brain barrier (BBB). Mice were scanned before and after administration of the contrast agent. Signal enhancement maps were generated, and the percentage signal change was calculated. The severity of the neuroinflammation was also assessed. Statistical analysis of the signal change data revealed a significantly (P = 0.028) higher signal enhancement in mice at 28 days post-infection (least squares mean = 26.709) compared with uninfected animals (6.298), indicating the presence of BBB impairment. Leukocytes were found in the meninges and perivascular space of some blood vessels in the infected mice. This study shows that the integrity of the BBB is compromised during CNS stage trypanosomiasis and that the impairment does not correlate with inflammatory cell infiltration.
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Affiliation(s)
- Jean Rodgers
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
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17
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Douglas SD, Leeman SE. Neurokinin-1 receptor: functional significance in the immune system in reference to selected infections and inflammation. Ann N Y Acad Sci 2010; 1217:83-95. [PMID: 21091716 DOI: 10.1111/j.1749-6632.2010.05826.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The G protein-coupled receptor (GPCR), neurokinin-1 receptor (NK1R), and its preferred ligand, substance P (SP), are reviewed in relationship to the immune system and selected infections. NK1R and SP are ubiquitous throughout the animal kingdom. This important pathway has unique functions in numerous cells and tissues. The interaction of SP with its preferred receptor, NK1R, leads to the activation of nuclear factor-kappa B (NF-κB) and proinflammatory cytokines. NK1R has two isoforms, both a full-length and a truncated form. These isoforms have different functional significances and differ in cell signaling capability. The proinflammatory signals modulated by SP are important in bacterial, viral, fungal, and parasitic diseases, as well as in immune system function. The SP-NK1R system is a major class 1, rhodopsin-like GPCR ligand-receptor interaction.
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Affiliation(s)
- Steven D Douglas
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, University of Pennsylvania Medical School, Philadelphia, Pennsylvania, USA.
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18
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Abstract
SUMMARYNeurological involvement following trypanosome infection has been recognised for over a century. However, there are still many unanswered questions concerning the mechanisms used by the parasite to gain entry to the CNS and the pathogenesis of the resulting neuroinflammatory reaction. There is a paucity of material from human cases of the disease therefore the majority of current research relies on the use of animal models of trypanosome infection. This review reports contemporary knowledge, from both animal models and human samples, regarding parasite invasion of the CNS and the neuropathological changes that accompany trypanosome infection and disease progression. The effects of trypanosomes on the blood-brain barrier are discussed and possible key molecules in parasite penetration of the barrier highlighted. Changes in the balance of CNS cytokines and chemokines are also described. The article closes by summarising the effects of trypanosome infection on the circadian sleep-wake cycle, and sleep structure, in relation to neuroinflammation and parasite location within the CNS. Although a great deal of progress has been made in recent years, the advent and application of sophisticated analysis techniques, to decipher the complexities of HAT pathogenesis, herald an exciting and rewarding period for advances in trypanosome research.
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Abstract
The neurological complications of human African trypanosomiasis (HAT) in man caused by the unicellular protozoan parasites Trypanosoma brucei gambiense and T. b. rhodesiense are a consequence of the penetration of the blood-brain barrier (BBB) by trypanosomes that enter the central nervous system (CNS). Yet the mechanisms by which African trypanosomes cross the true BBB comprised of brain microvascular endothelial cells (BMECs) remain unclear. Human BBB models used to determine how African trypanosomes initially interact in vitro with the human BBB proper suggest that parasites cross the human BBB in part by generating Ca(2+) activation signals in human BMECs through the activity of parasite cysteine proteases. In vivo murine models of HAT have suggested additional mechanisms of BBB traversal by trypanosomes, with recent compelling evidence for the important role of interferon-gamma in facilitating this process. A clear understanding of how trypanosomes enter the CNS is critical for both understanding the neuropathogenesis of HAT and in developing more effective drug therapies for late-stage disease.
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Affiliation(s)
- Dennis J Grab
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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21
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Abstract
Human African trypanosomiasis, also known as sleeping sickness, is a neglected disease, and it continues to pose a major threat to 60 million people in 36 countries in sub-Saharan Africa. Transmitted by the bite of the tsetse fly, the disease is caused by protozoan parasites of the genus Trypanosoma and comes in two types: East African human African trypanosomiasis caused by Trypanosoma brucei rhodesiense and the West African form caused by Trypanosoma brucei gambiense. There is an early or hemolymphatic stage and a late or encephalitic stage, when the parasites cross the blood-brain barrier to invade the central nervous system. Two critical current issues are disease staging and drug therapy, especially for late-stage disease. Lumbar puncture to analyze cerebrospinal fluid will remain the only method of disease staging until reliable noninvasive methods are developed, but there is no widespread consensus as to what exactly defines biologically central nervous system disease or what specific cerebrospinal fluid findings should justify drug therapy for late-stage involvement. All four main drugs used for human African trypanosomiasis are toxic, and melarsoprol, the only drug that is effective for both types of central nervous system disease, is so toxic that it kills 5% of patients who receive it. Eflornithine, alone or combined with nifurtimox, is being used increasingly as first-line therapy for gambiense disease. There is a pressing need for an effective, safe oral drug for both stages of the disease, but this will require a significant increase in investment for new drug discovery from Western governments and the pharmaceutical industry.
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Division of Clinical Neurosciences, Faculty of Medicine, University of Glasgow Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, UK.
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Chauhan VS, Sterka DG, Gray DL, Bost KL, Marriott I. Neurogenic exacerbation of microglial and astrocyte responses to Neisseria meningitidis and Borrelia burgdorferi. J Immunol 2008; 180:8241-9. [PMID: 18523290 DOI: 10.4049/jimmunol.180.12.8241] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although glial cells are recognized for their roles in maintaining neuronal function, there is growing appreciation of the ability of resident CNS cells to initiate and/or augment inflammation following trauma or infection. The tachykinin, substance P (SP), is well known to augment inflammatory responses at peripheral sites and its presence throughout the CNS raises the possibility that this neuropeptide might serve a similar function within the brain. In support of this hypothesis, we have recently demonstrated the expression of high affinity receptors for SP (Neurokinin-1 (NK-1) receptors) on microglia and shown that this tachykinin can significantly elevate bacterially induced inflammatory prostanoid production by isolated cultures of these cells. In the present study, we demonstrate that endogenous SP/NK-1R interactions are an essential component in the initiation and/or progression of CNS inflammation in vivo following exposure to two clinically relevant bacterial CNS pathogens, Neisseria meningitidis and Borrelia burgdorferi. We show that in vivo elevations in inflammatory cytokine production and decreases in the production of an immunosuppressive cytokine are markedly attenuated in mice genetically deficient in the expression of the NK-1R or in mice treated with a specific NK-1R antagonist. Furthermore, we have used isolated cultures of microglia and astrocytes to demonstrate that SP can augment inflammatory cytokine production by these resident CNS cell types following exposure to either of these bacterial pathogens. Taken together, these studies indicate a potentially important role for neurogenic exacerbation of resident glial immune responses in CNS inflammatory diseases, such as bacterial meningitis.
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Affiliation(s)
- Vinita S Chauhan
- Department of Biology, University of North Carolina, Charlotte, NC 28223, USA
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Antoine-Moussiaux N, Magez S, Desmecht D. Contributions of experimental mouse models to the understanding of African trypanosomiasis. Trends Parasitol 2008; 24:411-8. [PMID: 18684669 DOI: 10.1016/j.pt.2008.05.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 05/08/2008] [Accepted: 05/27/2008] [Indexed: 12/01/2022]
Abstract
African trypanosomiasis is the collective name for a wide variety of trypanosome infections that affect humans and livestock. In recent years, experimental mice infection models have provided new insights into both human and animal trypanosomiasis. Mouse models seem to be a valuable and versatile tool in trypanosomiasis-associated pathology and immunology research and highlight the variety shown by African trypanosomiases. Indeed, inbred mouse strains have enabled the study of genetic determinants of susceptibility and of the roles of anti-parasite antibodies, inflammatory mediators and anti-inflammatory mediators for each trypanosome species. Remarkable advances relating to the encephalitic stage of sleeping sickness have also been achieved thanks to murine models. The different contributions of murine models to the African trypanosomiases knowledge are presented here. Future search directions are finally proposed, with respect to mouse model opportunities and limitations.
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Affiliation(s)
- Nicolas Antoine-Moussiaux
- Department of Animal Pathology, Veterinary College, University of Liege, 20 Boulevard de Colonster, B43, 4000 Liege, Belgium.
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24
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Wang X, Douglas SD, Song L, Wang YJ, Ho WZ. Neurokinin-1 receptor antagonist (aprepitant) suppresses HIV-1 infection of microglia/macrophages. J Neuroimmune Pharmacol 2008; 3:257-64. [PMID: 18654860 DOI: 10.1007/s11481-008-9117-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 07/01/2008] [Indexed: 11/30/2022]
Abstract
Neurokinin-1 receptor (NK-1R) antagonists suppress HIV-1 infection of macrophages in vitro. We have further investigated the anti-HIV-1 activity of aprepitant, a Food and Drug Administration-approved NK-1R antagonist, and its cytotoxic effect in the macrophage/microglia system. Aprepitant inhibited infection of macrophages with primary HIV-1 R5 strains (subtypes A, D, and H; UG275, BZ163, and BCF-KITA), while it had little effect on primary HIV-1 X4 strains (subtypes B and D, BZ167 and SE365). Aprepitant, when added to microglia cultures infected with CSF-derived HIV-1 strains (JAGO or JRFL), significantly inhibited viral replication. Aprepitant also enhanced the anti-HIV-1 activity of enfuvirtide (an HIV-1 fusion inhibitor) in HIV-1-infected macrophages. Over a concentration range of 10(-9) to 10(-5) M, aprepitant had little cytotoxic effect (less than 10%) on macrophages during the in vitro cultures. Autologous human serum (< or =20%) had little effect on the anti-HIV-1 activity of aprepitant in macrophages. These observations provide additional evidence to support the potential use of NK-1R antagonists as therapeutic and immunomodulatory agents for the treatment of HIV-1 infection.
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Affiliation(s)
- Xu Wang
- Department of Pediatrics, Joseph Stokes, Jr. Research Institute at The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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25
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Rodgers J, Bradley B, Kennedy PGE. Combination chemotherapy with a substance P receptor antagonist (aprepitant) and melarsoprol in a mouse model of human African trypanosomiasis. Parasitol Int 2007; 56:321-4. [PMID: 17643344 DOI: 10.1016/j.parint.2007.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2007] [Revised: 06/13/2007] [Accepted: 06/20/2007] [Indexed: 11/25/2022]
Abstract
Drug therapy for late-stage (encephalitic) human African trypanosomiasis (HAT) is currently very unsatisfactory with the most commonly used drug, melarsoprol, having a 5% overall mortality. There is evidence in a mouse model of HAT that Substance P (SP) receptor antagonism reduces the neuroinflammatory reaction to CNS trypanosome infection. In this study we investigated the effects of combination chemotherapy with melarsoprol and a humanised SP receptor antagonist aprepitant (EMEND) in this mouse model. The melarsoprol/aprepitant drug combination did not produce any clinical signs of illness in mice with CNS trypanosome infection. This lack of any additional or unexpected CNS toxicity in the mouse model of CNS HAT provides valuable safety data for the future possible use of this drug combination in patients with late-stage HAT.
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Affiliation(s)
- Jean Rodgers
- Division of Infection and Immunity, Faculty of Veterinary Medicine, Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, UK
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26
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Kennedy PGE. Animal models of human African trypanosomiasis--very useful or too far removed? Trans R Soc Trop Med Hyg 2007; 101:1061-2. [PMID: 17548098 DOI: 10.1016/j.trstmh.2007.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022] Open
Abstract
Animal models of human African trypanosomiasis, also known as sleeping sickness, have been used for many years both to investigate disease pathogenesis and to test novel drug therapies. Model systems used have included mice, rats and non-human primates such as monkeys. Whilst such animal models have some definite but unavoidable limitations, it is argued that these are outweighed by their advantages. The latter include the ability to investigate disease pathogenesis mechanistically and the mechanisms of trypanosome traversal of the blood-brain barrier, as well as the identification of new potential drug targets and staging biomarkers, new drug therapies and combinations, and potential drug toxicity.
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Division of Clinical Neurosciences, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK.
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27
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Reinke EK, Johnson MJ, Ling C, Karman J, Lee J, Weinstock JV, Sandor M, Fabry Z. Substance P receptor mediated maintenance of chronic inflammation in EAE. J Neuroimmunol 2006; 180:117-25. [PMID: 16942803 DOI: 10.1016/j.jneuroim.2006.07.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 06/09/2006] [Accepted: 07/06/2006] [Indexed: 10/24/2022]
Abstract
Substance P (SP) is a modulatory, pro-inflammatory neuropeptide. We investigated the role of the SP receptor, neurokinin-1 (NK-1), in EAE. Our data show that in the chronic phase, mice lacking NK-1 have improved mobility and decreased numbers of LFA-1 high CD4+ T cells and MOG-specific, IFN-gamma producing CD4+ T cells. SR140333, an NK-1 antagonist, administered alone during the chronic phase of EAE was not sufficient to ameliorate symptoms. These results indicate that SP, through NK-1, contributes to maintenance of CNS inflammation, and combining NK-1 antagonists with conventional anti-inflammatory treatments may enhance the success of treatments for diseases like multiple sclerosis.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/pharmacology
- Anti-Inflammatory Agents/therapeutic use
- CD4-Positive T-Lymphocytes/immunology
- Chronic Disease/therapy
- Disease Models, Animal
- Drug Synergism
- Drug Therapy, Combination
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/metabolism
- Encephalomyelitis, Autoimmune, Experimental/physiopathology
- Female
- Immunity, Cellular/drug effects
- Immunity, Cellular/immunology
- Immunosuppression Therapy/methods
- Immunosuppression Therapy/standards
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Motor Activity/drug effects
- Motor Activity/immunology
- Myelin Proteins
- Myelin-Associated Glycoprotein/immunology
- Myelin-Oligodendrocyte Glycoprotein
- Neuroimmunomodulation/immunology
- Neurokinin-1 Receptor Antagonists
- Piperidines/pharmacology
- Piperidines/therapeutic use
- Quinuclidines/pharmacology
- Quinuclidines/therapeutic use
- Receptors, Neurokinin-1/genetics
- Substance P/immunology
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Affiliation(s)
- Emily K Reinke
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison WI, United States
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28
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Abstract
Human African Trypanosomiasis (HAT),which is also known as sleeping sickness, is a major cause of death and disability in 36 countries in sub-Saharan Africa. The disease is caused by the protozoan parasite of the Trypanosoma genus which is transmitted by the bite of the tsetse fly. The two types of HAT, the East African form due to Trypanosoma b.rhodesiensei (T. b.rhodesiensi) and the West African form due to T. b.gambiense, differ in their tempo of infection but in both cases the disease is always fatal if untreated. As well as multiple systemic features seen in the early (haemolymphatic) stage of disease, the late (encephalitic stage) stage, is associated with a wide range of neurological features including neuropsychiatric, motor and sensory abnormalities. Accurate staging of the disease is absolutely essential because of the potentially fatal complications of melarsoprol treatment of late-stage disease, the most important of which is a severe post-treatment reactive encephalopathy (PTRE) the pathogenesis of which is not fully understood. However, there is not a universal consensus as to how late-stage disease should be diagnosed using CSF criteria, and this has been very problematic in HAT. A more recent alternative drug for late stage gambiense disease is eflornithine (DFMO). There is a pressing need for a non-toxic oral drug for both early and late stage disease that would obviate many of the problems of staging, and various possible strategies to achieve this goal are currently underway. However, control of the disease will also require more effective measures of reducing man/fly contact and also the allocation of much greater financial and infrastructural resources than are currently available in Africa.
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Division of Clinical Neurosciences, University of Glasgow Southern General Hospital, Institute of Neurological Sciences, Glasgow G51 4TF, Scotland, UK.
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29
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Kennedy PGE. Diagnostic and neuropathogenesis issues in human African trypanosomiasis. Int J Parasitol 2006; 36:505-12. [PMID: 16546191 DOI: 10.1016/j.ijpara.2006.01.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 01/23/2006] [Accepted: 01/30/2006] [Indexed: 11/17/2022]
Abstract
Human African trypanosomiasis, also known as sleeping sickness, is caused by protozoan parasites of the genus Trypanosoma, and is a major cause of human mortality and morbidity. The East African and West African variants, caused by Trypanosma brucei rhodesiense and Trypanosoma brucei gambiense, respectively, differ in their presentation but the disease is fatal if untreated. Accurate staging of the disease into the early haemolymphatic stage and the late encephalitic stage is critical as the treatment for the two stages is different. The only effective drug for late stage disease, melarsoprol, which crosses the blood-brain barrier, is followed by a severe post-treatment reactive encephalopathy in 10% of cases of which half die. There is no current consensus on the diagnostic criteria for CNS involvement and the specific indications for melarsoprol therapy also differ. There is a pressing need for a quick, simple, cheap and reliable diagnostic test to diagnose Human African trypanosomiasis in the field and also to determine CNS invasion. Cerebrospinal fluid and plasma analyses in patients with Human African trypanosomiasis have indicated a role for both pro-inflammatory and counter-inflammatory cytokines in determining the severity of the meningoencephalitis of late stage disease, and, at least in T. b. rhodesiense infection, the balance of these opposing cytokines may be critical. Rodent models of Human African trypanosomiasis have proved very useful in modelling the post-treatment reactive encephalopathy of humans and have demonstrated the central role of astrocyte activation and cytokine balances in determining CNS disease. Such animal models have also allowed a greater understanding of the more direct mechanisms of trypanosome infection on CNS function including the disruption of circadian rhythms, as well as the immunological determinants of passage of trypanosomes across the blood-brain barrier.
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Affiliation(s)
- Peter G E Kennedy
- Division of Clinical Neurosciences, Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, University of Glasgow, Glasgow G51 4TF, Scotland, UK.
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30
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Sternberg JM, Rodgers J, Bradley B, Maclean L, Murray M, Kennedy PGE. Meningoencephalitic African trypanosomiasis: Brain IL-10 and IL-6 are associated with protection from neuro-inflammatory pathology. J Neuroimmunol 2005; 167:81-9. [PMID: 16054238 DOI: 10.1016/j.jneuroim.2005.06.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Accepted: 06/20/2005] [Indexed: 12/27/2022]
Abstract
The relationship of neuropathology to CNS inflammatory and counter-inflammatory cytokine production in African trypanosome-infected mice was studied using an infection model with a defined disease progression. The initial phase of CNS infection by trypanosomes, where only mild neuropathology is evident, was characterised by high levels of IL-10 and IL-6. In the later phase of CNS infection and in a post-drug treatment model, moderate to severe neuropathology was associated with high levels of IFN-gamma and TNF-alpha. The relationship of these cytokines to neuropathological grade suggests that IL-10 and IL-6 protect the CNS from inflammatory pathology when parasites first enter the brain and the data reconcile previously contradictory clinical measurements of CSF cytokines in meningoencephalitic patients with post-mortem histopathology observations.
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Affiliation(s)
- Jeremy M Sternberg
- School of Biological Sciences, Zoology Building, University of Aberdeen, Aberdeen AB24 2TZ, UK.
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32
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Abstract
The peptides of the tachykinin family are widely distributed within the mammalian peripheral and central nervous systems and play a well-recognized role as excitatory neurotransmitters. Currently, the concept that tachykinins act exclusively as neuropeptides is being challenged, since the best known members of the family, substance P, neurokinin A and neurokinin B, are also present in non-neuronal cells and in non-innervated tissues. Moreover, the recently cloned mammalian tachykinins hemokinin-1 and endokinins are primarily expressed in non-neuronal cells, suggesting a widespread distribution and important role for these peptides as intercellular signaling molecules. The biological actions of tachykinins are mediated through three types of receptors denoted NK(1), NK(2) and NK(3) that belong to the family of G protein-coupled receptors. The identification of additional tachykinins has reopened the debate of whether more tachykinin receptors exist. In this review, we summarize the current knowledge of tachykinins and their receptors.
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Affiliation(s)
- Jocelyn N Pennefather
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, Parkville, Victoria 3052, Australia
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33
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Abstract
Human African trypanosomiasis (HAT), also known as sleeping sickness, is a major cause of mortality and morbidity in sub-Saharan Africa. Current therapy with melarsoprol for CNS HAT has unacceptable side-effects with an overall mortality of 5%. This review discusses the issues of diagnosis and staging of CNS disease, its neuropathogenesis, and the possibility of new therapies for treating late-stage disease.
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Division of Clinical Neurosciences, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, United Kingdom.
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