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Yaiw KC, Mohammad AA, Taher C, Cui HL, Costa H, Kostopoulou ON, Jung M, Assinger A, Wilhelmi V, Yang J, Strååt K, Rahbar A, Pernow J, Söderberg-Nauclér C. Human Cytomegalovirus Reduces Endothelin-1 Expression in Both Endothelial and Vascular Smooth Muscle Cells. Microorganisms 2021; 9:microorganisms9061137. [PMID: 34070407 PMCID: PMC8229579 DOI: 10.3390/microorganisms9061137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 11/16/2022] Open
Abstract
Human cytomegalovirus (HCMV) is an opportunistic pathogen that has been implicated in the pathogenesis of atherosclerosis. Endothelin-1 (ET-1), a potent vasoconstrictive peptide, is overexpressed and strongly associated with many vasculopathies. The main objective of this study was to investigate whether HCMV could affect ET-1 production. As such, both endothelial and smooth muscle cells, two primary cell types involved in the pathogenesis of atherosclerosis, were infected with HCMV in vitro and ET-1 mRNA and proteins were assessed by quantitative PCR assay, immunofluorescence staining and ELISA. HCMV infection significantly decreased ET-1 mRNA and secreted bioactive ET-1 levels from both cell types and promoted accumulation of the ET-1 precursor protein in infected endothelial cells. This was associated with inhibition of expression of the endothelin converting enzyme-1 (ECE-1), which cleaves the ET-1 precursor protein to mature ET-1. Ganciclovir treatment did not prevent the virus suppressive effects on ET-1 expression. Consistent with this observation we identified that the IE2-p86 protein predominantly modulated ET-1 expression. Whether the pronounced effects of HCMV in reducing ET-1 expression in vitro may lead to consequences for regulation of the vascular tone in vivo remains to be proven.
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Affiliation(s)
- Koon-Chu Yaiw
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
- Correspondence: (K.-C.Y.); (C.S.-N.)
| | - Abdul-Aleem Mohammad
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - Chato Taher
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - Huanhuan Leah Cui
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - Helena Costa
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - Ourania N. Kostopoulou
- Department of Oncology and Pathology, Karolinska Institutet, SE 171 64 Stockholm, Sweden;
| | - Masany Jung
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - Alice Assinger
- Institute of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria;
| | - Vanessa Wilhelmi
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - Jiangning Yang
- Department of Molecular Medicine and Surgery, Karolinska Institutet and University Hospital Solna, SE 171 64 Stockholm, Sweden; (J.Y.); (J.P.)
| | - Klas Strååt
- Department of Medicine, Division of Hematology, BioClinicum and Centre for Molecular Medicine, Karolinska University, Hospital Solna and Karolinska Institutet, SE 171 64 Stockholm, Sweden;
| | - Afsar Rahbar
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
| | - John Pernow
- Department of Molecular Medicine and Surgery, Karolinska Institutet and University Hospital Solna, SE 171 64 Stockholm, Sweden; (J.Y.); (J.P.)
| | - Cecilia Söderberg-Nauclér
- Department of Medicine, Solna, Microbial Pathogenesis Unit, Karolinska Institutet, SE 171 64 Stockholm, Sweden; (A.-A.M.); (C.T.); (H.L.C.); (H.C.); (M.J.); (V.W.); (A.R.)
- Division of Neurology, Karolinska University Hospital, SE 171 64 Stockholm, Sweden
- Correspondence: (K.-C.Y.); (C.S.-N.)
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Koyama Y. Endothelin ET B Receptor-Mediated Astrocytic Activation: Pathological Roles in Brain Disorders. Int J Mol Sci 2021; 22:ijms22094333. [PMID: 33919338 PMCID: PMC8122402 DOI: 10.3390/ijms22094333] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022] Open
Abstract
In brain disorders, reactive astrocytes, which are characterized by hypertrophy of the cell body and proliferative properties, are commonly observed. As reactive astrocytes are involved in the pathogenesis of several brain disorders, the control of astrocytic function has been proposed as a therapeutic strategy, and target molecules to effectively control astrocytic functions have been investigated. The production of brain endothelin-1 (ET-1), which increases in brain disorders, is involved in the pathophysiological response of the nervous system. Endothelin B (ETB) receptors are highly expressed in reactive astrocytes and are upregulated by brain injury. Activation of astrocyte ETB receptors promotes the induction of reactive astrocytes. In addition, the production of various astrocyte-derived factors, including neurotrophic factors and vascular permeability regulators, is regulated by ETB receptors. In animal models of Alzheimer’s disease, brain ischemia, neuropathic pain, and traumatic brain injury, ETB-receptor-mediated regulation of astrocytic activation has been reported to improve brain disorders. Therefore, the astrocytic ETB receptor is expected to be a promising drug target to improve several brain disorders. This article reviews the roles of ETB receptors in astrocytic activation and discusses its possible applications in the treatment of brain disorders.
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Affiliation(s)
- Yutaka Koyama
- Laboratory of Pharmacology, Kobe Pharmaceutical University, 4-19-1 Motoyama-Kita Higashinada, Kobe 668-8558, Japan
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3
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Hostenbach S, D'Haeseleer M, Kooijman R, De Keyser J. Modulation of Cytokine-Induced Astrocytic Endothelin-1 Production as a Possible New Approach to the Treatment of Multiple Sclerosis. Front Pharmacol 2020; 10:1491. [PMID: 31969819 PMCID: PMC6960227 DOI: 10.3389/fphar.2019.01491] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/19/2019] [Indexed: 12/29/2022] Open
Abstract
Background: In the human central nervous system (CN), resting astrocytes do not visually show endothelin-1 (ET-1)-like immunoreactivity. In patients with multiple sclerosis (MS), an inflammatory disorder of the CNS, high levels of ET-1 are found in reactive astrocytes in demyelinated plaques. ET-1 may contribute to the pathology of MS by interrupting the blood-brain-barrier, enhancing inflammatory responses, excitotoxicity and reducing cerebral blood flow. Methods: We used the human astrocytoma cell line 1321N1 to investigate the role of inflammatory cytokines involved in MS lesions (IL-1β, TNF-α, IFN-γ, LPS, IL-10, TGF-β) on astrocytic ET-1 upregulation. Prucalopride, rolipram, fenofibrate, fluoxetine, simvastatin, daglutril, and resveratrol were investigated as potential candidate drugs to suppress cytokine-induced astrocytic ET-1 production. Effects on ET-1 production were measured using both ELISA and RT-qPCR. Results and Conclusions: ET-1 secretion by astrocytoma cells was only stimulated by the pro-inflammatory cytokines IL-1β and TNF-α. Fluoxetine, simvastatin, and resveratrol significantly inhibited this IL-1β- and TNF-α-induced ET-1 production. Simvastatin and resveratrol significantly reduced ET-1 mRNA levels, indicating an effect at the level of transcription. Fluoxetine significantly reduced endothelin converting enzyme-1 mRNA levels, suggesting and effect at the level of protein-processing. The required concentrations of simvastatin (>0.1 µM) and resveratrol (>10 µM) cannot be achieved in humans using pharmacologically accepted doses. Fluoxetine exerted a significant inhibitory effect on ET-1 secretion at a concentration of 5 µM, which is pharmacologically achievable in human brain, but the effect was modest (<50% suppression) and probably not sufficient to obtain a clinically relevant ET-1 effect. Our in vitro model can be a useful screening tool in the development of new drugs to suppress astrocytic ET-1 production. The effect of simvastatin was for the most part mediated via the mevalonate pathway, suggesting that this might be an interesting target for further drug development.
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Affiliation(s)
- Stéphanie Hostenbach
- Department of Neurology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Miguel D'Haeseleer
- Department of Neurology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Department of Neurology, National Multiple Sclerosis Centrum, Melsbroek, Belgium
| | - Ron Kooijman
- Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Jacques De Keyser
- Department of Neurology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Department of Neurology, Universitair Medisch Centrum Groningen (UMCG), University of Groningen, Groningen, Netherlands
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4
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Abstract
Endothelins were discovered more than thirty years ago as potent vasoactive compounds. Beyond their well-documented cardiovascular properties, however, the contributions of the endothelin pathway have been demonstrated in several neuroinflammatory processes and the peptides have been reported as clinically relevant biomarkers in neurodegenerative diseases. Several studies report that endothelin-1 significantly contributes to the progression of neuroinflammatory processes, particularly during infections in the central nervous system (CNS), and is associated with a loss of endothelial integrity at the blood brain barrier level. Because of the paucity of clinical trials with endothelin-1 antagonists in several infectious and non-infectious neuroinflammatory diseases, it remains an open question whether the 21 amino acid peptide is a mediator/modulator rather than a biomarker of the progression of neurodegeneration. This review focuses on the potential roles of endothelins in the pathology of neuroinflammatory processes, including infectious diseases of viral, bacterial or parasitic origin in which the synthesis of endothelins or its pharmacology have been investigated from the cell to the bedside in several cases, as well as in non-infectious inflammatory processes such as neurodegenerative disorders like Alzheimers Disease or central nervous system vasculitis.
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Yang L, Niu F, Yao H, Liao K, Chen X, Kook Y, Ma R, Hu G, Buch S. Exosomal miR-9 Released from HIV Tat Stimulated Astrocytes Mediates Microglial Migration. J Neuroimmune Pharmacol 2018; 13:330-344. [PMID: 29497921 DOI: 10.1007/s11481-018-9779-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/19/2018] [Indexed: 12/22/2022]
Abstract
Chronic neuroinflammation still remains a common underlying feature of HIV-infected patients on combined anti-retroviral therapy (cART). Previous studies have reported that despite near complete suppression of virus replication by cART, cytotoxic viral proteins such as HIV trans-activating regulatory protein (Tat) continue to persist in tissues such as the brain and the lymph nodes, thereby contributing, in part, to chronic glial activation observed in HIV-associated neurological disorders (HAND). Understanding how the glial cells cross talk to mediate neuropathology is thus of paramount importance. MicroRNAs (miR) also known as regulators of gene expression, have emerged as key paracrine signaling mediators that regulate disease pathogenesis and cellular crosstalk, through their transfer via the extracellular vesicles (EV). In the current study we have identified a novel function of miR-9, that of mediating microglial migration. We demonstrate that miR-9 released from Tat-stimulated astrocytes can be taken up by microglia resulting in their migratory phenotype. Exposure of human astrocytoma (A172) cells to HIV Tat resulted in induction and release of miR-9 in the EVs, which, was taken up by microglia, leading in turn, increased migration of the latter cells, a process that could be blocked by both an exosome inhibitor GW4869 or a specific target protector of miR-9. Furthermore, it was also demonstrated that EV miR-9 mediated inhibition of the expression of target PTEN, via its binding to the 3'UTR seed sequence of the PTEN mRNA, was critical for microglial migration. To validate the role of miR-9 in this process, microglial cells were treated with EVs loaded with miR-9, which resulted in significant downregulation of PTEN expression with a concomitant increase in microglial migration. These findings were corroborated by transfecting microglia with a specific target protector of PTEN, that blocked miR-9-mediated downregulation of PTEN as well as microglial migration. In vivo studies wherein the miR-9 precursor-transduced microglia were transplanted into the striatum of mice, followed by assessing their migration in response to a stimulus administered distally, further validated the role of miR-9 in mediating microglial migration. Collectively, our findings provide evidence that glial crosstalk via miRs released from EVs play a vital role in mediating disease pathogenesis and could provide new avenues for development of novel therapeutic strategies aimed at dampening neuropathogenesis.
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Affiliation(s)
- Lu Yang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Fang Niu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Honghong Yao
- Department of Pharmacology, Medical School of Southeast University, Southeast University, Nanjing, China.,Key Laboratory of Developmental Genes and Human Disease, Southeast University, Institute of Life Sciences, Nanjing, China
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Xufeng Chen
- The first Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Yeonhee Kook
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Rong Ma
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Guoku Hu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA.
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6
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Bivalkar-Mehla S, Mehla R, Chauhan A. Chimeric peptide-mediated siRNA transduction to inhibit HIV-1 infection. J Drug Target 2016; 25:307-319. [PMID: 27800697 DOI: 10.1080/1061186x.2016.1245311] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Persistent human immunodeficiency virus 1 (HIV-1) infection provokes immune activation and depletes CD4+ lymphocytes, leading to acquired immunodeficiency syndrome. Uninterrupted administration of combination antiretroviral therapy (cART) in HIV-infected patients suppresses viral replication to below the detectable level and partially restores the immune system. However, cART-unresponsive residual HIV-1 infection and elusive transcriptionally silent but reactivatable viral reservoirs maintain a permanent viral DNA blue print. The virus rebounds within a few weeks after interruption of suppressive therapy. Adjunct gene therapy to control viral replication by ribonucleic acid interference (RNAi) is a post-transcriptional gene silencing strategy that could suppress residual HIV-1 burden and overcome viral resistance. Small interfering ribonucleic acids (siRNAs) are efficient transcriptional inhibitors, but need delivery systems to reach inside target cells. We investigated the potential of chimeric peptide (FP-PTD) to deliver specific siRNAs to HIV-1-susceptible and permissive cells. Chimeric FP-PTD peptide was designed with an RNA binding domain (PTD) to bind siRNA and a cell fusion peptide domain (FP) to enter cells. FP-PTD-siRNA complex entered and inhibited HIV-1 replication in susceptible cells, and could be a candidate for in vivo testing.
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Affiliation(s)
- Shalmali Bivalkar-Mehla
- a Department of Pathology, Microbiology and Immunology , University of South Carolina School of Medicine , Columbia , SC , USA
| | - Rajeev Mehla
- a Department of Pathology, Microbiology and Immunology , University of South Carolina School of Medicine , Columbia , SC , USA
| | - Ashok Chauhan
- a Department of Pathology, Microbiology and Immunology , University of South Carolina School of Medicine , Columbia , SC , USA
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7
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The pathophysiological role of astrocytic endothelin-1. Prog Neurobiol 2016; 144:88-102. [DOI: 10.1016/j.pneurobio.2016.04.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/23/2016] [Accepted: 04/25/2016] [Indexed: 12/13/2022]
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8
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Abstract
Autophagy, a lysosomal degradative pathway that maintains cellular homeostasis, has emerged as an innate immune defense against pathogens. The role of autophagy in the deregulated HIV-infected central nervous system (CNS) is unclear. We have found that HIV-1-induced neuro-glial (neurons and astrocytes) damage involves modulation of the autophagy pathway. Neuro-glial stress induced by HIV-1 led to biochemical and morphological dysfunctions. X4 HIV-1 produced neuro-glial toxicity coupled with suppression of autophagy, while R5 HIV-1-induced toxicity was restricted to neurons. Rapamycin, a specific mTOR inhibitor (autophagy inducer) relieved the blockage of the autophagy pathway caused by HIV-1 and resulted in neuro-glial protection. Further understanding of the regulation of autophagy by cytokines and chemokines or other signaling events may lead to recognition of therapeutic targets for neurodegenerative diseases.
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Affiliation(s)
- Rajeev Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA
| | - Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA.
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9
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Chauhan A. Enigma of HIV-1 latent infection in astrocytes: an in-vitro study using protein kinase C agonist as a latency reversing agent. Microbes Infect 2015; 17:651-9. [PMID: 26043820 DOI: 10.1016/j.micinf.2015.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 11/29/2022]
Abstract
Purging HIV-1 to cure the infection in patients undergoing suppressive antiretroviral therapy requires targeting all possible viral reservoirs. Other than the memory CD4(+) T cells, several other HIV-1 reservoirs have been identified. HIV-1 infection in the brain as a reservoir is well documented, but not fully characterized. There, microglia, perivascular macrophages, and astrocytes can be infected by HIV-1. HIV-1 infection in astrocytes has been described as a nonproductive and primarily a latent infection. Using primary human astrocytes, we investigated latent HIV-1 infection and tested phorbol 12-myristate 13-acetate (PMA), a protein kinase C agonist, as an HIV-1-latency- reversing agent in infected astrocytes. Chloroquine (CQ) was used to facilitate initial HIV-1 escape from endosomes in astrocytes. CQ significantly increased HIV-1 infection. But treatment with PMA or viral Tat protein was similar to untreated HIV-1-infected astrocytes. Long-term follow-up of VSV-envelope-pseudotyped HIV-1 infected astrocytes showed persistent infection for 110 days, indicating the active state of the virus.
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Affiliation(s)
- Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA.
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10
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Maggi P, Bellacosa C, Grattagliano V, Pastore G, Lapadula G. Functional Impairments of Microcirculation in HIV-Positive Patients: A Laser Doppler Fluxometry-Based Investigation. HIV CLINICAL TRIALS 2015; 9:428-33. [DOI: 10.1310/hct0906-428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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The endothelin system has a significant role in the pathogenesis and progression of Mycobacterium tuberculosis infection. Infect Immun 2014; 82:5154-65. [PMID: 25267836 DOI: 10.1128/iai.02304-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Tuberculosis (TB) remains a major global health problem, and although multiple studies have addressed the relationship between Mycobacterium tuberculosis and the host on an immunological level, few studies have addressed the impact of host physiological responses. Proteases produced by bacteria have been associated with important alterations in the host tissues, and a limited number of these enzymes have been characterized in mycobacterial species. M. tuberculosis produces a protease called Zmp1, which appears to be associated with virulence and has a putative action as an endothelin-converting enzyme. Endothelins are a family of vasoactive peptides, of which 3 distinct isoforms exist, and endothelin 1 (ET-1) is the most abundant and the best-characterized isoform. The aim of this work was to characterize the Zmp1 protease and evaluate its role in pathogenicity. Here, we have shown that M. tuberculosis produces and secretes an enzyme with ET-1 cleavage activity. These data demonstrate a possible role of Zmp1 for mycobacterium-host interactions and highlights its potential as a drug target. Moreover, the results suggest that endothelin pathways have a role in the pathogenesis of M. tuberculosis infections, and ETA or ETB receptor signaling can modulate the host response to the infection. We hypothesize that a balance between Zmp1 control of ET-1 levels and ETA/ETB signaling can allow M. tuberculosis adaptation and survival in the lung tissues.
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Chauhan A, Tikoo A, Patel J, Abdullah AM. HIV-1 endocytosis in astrocytes: a kiss of death or survival of the fittest? Neurosci Res 2014; 88:16-22. [PMID: 25219546 DOI: 10.1016/j.neures.2014.08.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/14/2014] [Accepted: 08/18/2014] [Indexed: 12/23/2022]
Abstract
The brain is a target of HIV-1 and serves as an important viral reservoir. Astrocytes, the most abundant glial cell in the human brain, are involved in brain plasticity and neuroprotection. Several studies have reported HIV-1 infection of astrocytes in cell cultures and infected brain tissues. The prevailing concept is that HIV-1 infection of astrocytes leads to latent infection. Here, we provide our perspective on endocytosis-mediated HIV-1 entry and its fate in astrocytes. Natural entry of HIV-1 into astrocytes occurs via endocytosis. However, endocytosis of HIV-1 in astrocytes is a natural death trap where the majority of virus particles are degraded in endosomes and a few which escape intact lead to successful infection. Thus, regardless of artificial fine-tuning (treatment with cytokines or proinflammatory products) done to astrocytes, HIV-1 does not infect them efficiently unless the viral entry route or the endosomal enzymatic machinery has been manipulated.
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Affiliation(s)
- Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States; Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29209, United States.
| | - Akshay Tikoo
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
| | - Jankiben Patel
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
| | - Arwa Mujahid Abdullah
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
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13
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Chauhan A. Unperturbed posttranscriptional regulatory Rev protein function and HIV-1 replication in astrocytes. PLoS One 2014; 9:e106910. [PMID: 25188302 PMCID: PMC4154834 DOI: 10.1371/journal.pone.0106910] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/08/2014] [Indexed: 12/23/2022] Open
Abstract
Astrocytes protect neurons, but also evoke proinflammatory responses to injury and viral infections, including HIV. There is a prevailing notion that HIV-1 Rev protein function in astrocytes is perturbed, leading to restricted viral replication. In earlier studies, our finding of restricted viral entry into astrocytes led us to investigate whether there are any intracellular restrictions, including crippled Rev function, in astrocytes. Despite barely detectable levels of DDX3 (Rev-supporting RNA helicase) and TRBP (anti-PKR) in primary astrocytes compared to astrocytic cells, Rev function was unperturbed in wild-type, but not DDX3-ablated astrocytes. As in permissive cells, after HIV-1 entry bypass in astrocytes, viral-encoded Tat and Rev proteins had robust regulatory activities, leading to efficient viral replication. Productive HIV-1 infection in astrocytes persisted for several weeks. Our findings on HIV-1 entry bypass in astrocytes demonstrated that the intracellular environment is conducive to viral replication and that Tat and Rev functions are unperturbed.
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Affiliation(s)
- Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, and Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
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Endothelin-1 and its role in the pathogenesis of infectious diseases. Life Sci 2014; 118:110-9. [PMID: 24780317 DOI: 10.1016/j.lfs.2014.04.021] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/08/2014] [Accepted: 04/15/2014] [Indexed: 12/12/2022]
Abstract
Endothelins are potent regulators of vascular tone, which also have mitogenic, apoptotic, and immunomodulatory properties (Rubanyi and Polokoff, 1994; Kedzierski and Yanagisawa, 2001; Bagnato et al., 2011). Three isoforms of endothelin have been identified to date, with endothelin-1 (ET-1) being the best studied. ET-1 is classically considered a potent vasoconstrictor. However, in addition to the effects of ET-1 on vascular smooth muscle cells, the peptide is increasingly recognized as a pro-inflammatory cytokine (Teder and Noble, 2000; Sessa et al., 1991). ET-1 causes platelet aggregation and plays a role in the increased expression of leukocyte adhesion molecules, the synthesis of inflammatory mediators contributing to vascular dysfunction. High levels of ET-1 are found in alveolar macrophages, leukocytes (Sessa et al., 1991) and fibroblasts (Gu et al., 1991). Clinical and experimental data indicate that ET-1 is involved in the pathogenesis of sepsis (Tschaikowsky et al., 2000; Goto et al., 2012), viral and bacterial pneumonia (Schuetz et al., 2008; Samransamruajkit et al., 2002), Rickettsia conorii infections (Davi et al., 1995), Chagas disease (Petkova et al., 2000, 2001), and severe malaria (Dai et al., 2012; Machado et al., 2006; Wenisch et al., 1996a; Dietmann et al., 2008). In this minireview, we will discuss the role of endothelin in the pathogenesis of infectious processes.
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Hsieh WT, Yeh WL, Cheng RY, Lin C, Tsai CF, Huang BR, Wu CYJ, Lin HY, Huang SS, Lu DY. Exogenous endothelin-1 induces cell migration and matrix metalloproteinase expression in U251 human glioblastoma multiforme. J Neurooncol 2014; 118:257-269. [PMID: 24756349 DOI: 10.1007/s11060-014-1442-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 04/09/2014] [Indexed: 10/25/2022]
Abstract
Glioblastoma multiforme (GBM) is the most common and lethal type of primary brain tumor characterized by its rapid infiltration to surrounding tissues during the early stages. The fast spreading of GBM obscures the initiation of the tumor mass making the treatment outcome undesirable. Endothelin-1 is known as a secretory protein presented in various types of brain cells, which has been indicated as a factor for cancer pathology. The aim of the present study was to investigate the molecular mechanism of cell migration in GBM. We found that various malignant glioma cells expressed higher amounts of endothelin-1, ETA, and ETB receptors than nonmalignant human astrocytes. The application of endothelin-1 enhanced the migratory activity in human U251 glioma cells corresponding to increased expression of matrix metalloproteinase (MMP)-9 and MMP-13. The endothelin-1-induced cell migration was attenuated by MMP-9 and MMP-13 inhibitors and inhibitors of mitogen-activated protein (MAP) kinase and PI3 kinase/Akt. Furthermore, the elevated levels of phosphate c-Jun accumulation in the nucleus and activator protein-1 (AP-1)-DNA binding activity were also found in endothelin-1 treated glioma cells. In migration-prone sublines, cells with greater migration ability showed higher endothelin-1, ETB receptor, and MMP expressions. These results indicate that endothelin-1 activates MAP kinase and AP-1 signaling, resulting in enhanced MMP-9 and MMP-13 expressions and cell migration in GBM.
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Affiliation(s)
- Wen-Tsong Hsieh
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Wei-Lan Yeh
- Department of Cell and Tissue Engineering and Department of Medical Research, Changhua Christian Hospital, Changhua, Taiwan
| | - Ruo-Yuo Cheng
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Chingju Lin
- Department of Physiology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Cheng-Fang Tsai
- Department of Biotechnology, Asia University, Taichung, Taiwan
| | - Bor-Ren Huang
- Department of Neurosurgery, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
| | - Caren Yu-Ju Wu
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
| | - Hsiao-Yun Lin
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Shiang-Suo Huang
- Department of Pharmacology and Institute of Medicine, College of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Dah-Yuu Lu
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, No. 91 Hsueh-Shih Road, Taichung, Taiwan.
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Chauhan A, Mehla R, Vijayakumar TS, Handy I. Endocytosis-mediated HIV-1 entry and its significance in the elusive behavior of the virus in astrocytes. Virology 2014; 456-457:1-19. [PMID: 24889220 DOI: 10.1016/j.virol.2014.03.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/09/2014] [Accepted: 03/04/2014] [Indexed: 11/29/2022]
Abstract
Astrocytes protect neurons but also evoke a proinflammatory response to injury and viral infections including HIV. We investigated the mechanism of HIV-1 infection in primary astrocytes, which showed minimal but productive viral infection independent of CXCR4. As with ectopic-CD4-expressing astrocytes, lysosomotropic agents led to increased HIV-1 infection in wild-type but not Rabs 5, 7, and 11-ablated astrocytes. Instead, HIV-1 infection was decreased in Rab-depleted astrocytes, corroborating viral entry by endocytosis. HIV-1 produced persistent infection in astrocytes (160 days); no evidence of latent infection was seen. Notably, one caveat is that endosomal modifiers enhanced wild-type HIV-1 infection (M- and T-tropic) in astrocytes, suggesting endocytic entry of the virus. Impeding endocytosis by inhibition of Rab 5, 7 or 11 will inhibit HIV infection in astrocytes. Although the contribution of such low-level infection in astrocytes to neurological complications is unclear, it may serve as an elusive viral reservoir in the central nervous system.
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Affiliation(s)
- Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA; Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29209, USA.
| | - Rajeev Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA
| | | | - Indhira Handy
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, USA
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17
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Harati R, Villégier AS, Banks WA, Mabondzo A. Susceptibility of juvenile and adult blood-brain barrier to endothelin-1: regulation of P-glycoprotein and breast cancer resistance protein expression and transport activity. J Neuroinflammation 2012; 9:273. [PMID: 23253775 PMCID: PMC3547749 DOI: 10.1186/1742-2094-9-273] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 11/07/2012] [Indexed: 12/12/2022] Open
Abstract
Background P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) play a critical role in keeping neurotoxic substances from entering the brain. We and others have previously reported an impact of inflammation on the regulation of adult blood–brain barrier (BBB) efflux transporters. However, studies in children have not been done. From the pediatric clinical perspective, it is important to understand how the central nervous system (CNS) and BBB drug efflux transporters differ in childhood from those of adults under normal and inflammatory conditions. Therefore, we examined and compared the regulation of P-gp and BCRP expression and transport activity in young and adult BBB and investigated the molecular mechanisms underlying inflammatory responses. Methods Rats at postnatal day (P) P21 and P84, corresponding to the juvenile and adult stages of human brain maturation, respectively, were treated with endothelin-1 (ET-1) given by the intracerebroventricular (icv) route. Twenty-four hours later, we measured P-gp and BCRP protein expression in isolated brain capillary by immunoblotting as well as by transport activity in vivo by measuring the unbound drug partitioning coefficient of the brain (Kp,uu,brain) of known efflux transporter substrates administered intravenously. Glial activation was measured by immunohistochemistry. The release of cytokines/chemokines (interleukins-1α, 1-β (IL-1β), -6 (IL-6), -10 (IL-10), monocyte chemoattractant protein (MCP-1/CCL2), fractalkine and tissue inhibitor of metalloproteinases-1 (TIMP-1)) were simultaneously measured in brain and serum samples using the Agilent Technology cytokine microarray. Results We found that juvenile and adult BBBs exhibited similar P-gp and BCRP transport activities in the normal physiological conditions. However, long-term exposure of the juvenile brain to low-dose of ET-1 did not change BBB P-gp transport activity but tended to decrease BCRP transport activity in the juvenile brain, while a significant increase of the activity of both transporters was evidenced at the BBB in the adult brain. Moreover, juvenile and adult brain showed differences in their expression profiles of cytokines and chemokines mediated by ET-1. Conclusions BBB transporter activity during neuroinflammation differs between the juvenile and adult brains. These findings emphasize the importance of considering differential P-gp and BCRP transport regulation mechanisms between adult and juvenile BBB in the context of neuroinflammation.
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Affiliation(s)
- Rania Harati
- CEA, Direction des Sciences du Vivant, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
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18
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Mehla R, Bivalkar-Mehla S, Nagarkatti M, Chauhan A. Programming of neurotoxic cofactor CXCL-10 in HIV-1-associated dementia: abrogation of CXCL-10-induced neuro-glial toxicity in vitro by PKC activator. J Neuroinflammation 2012; 9:239. [PMID: 23078780 PMCID: PMC3533742 DOI: 10.1186/1742-2094-9-239] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 10/08/2012] [Indexed: 01/09/2023] Open
Abstract
Background More than 50% of patients undergoing lifelong suppressive antiviral treatment for HIV-1 infection develop minor HIV-1-associated neurocognitive disorders. Neurological complications during HIV-1 infection are the result of direct neuronal damage by proinflammatory products released from HIV-1-infected or -uninfected activated lymphocytes, monocytes, macrophages, microglia and astrocytes. The specific pro-inflammatory products and their roles in neurotoxicity are far from clear. We investigated proinflammatory cytokines and chemokines in the cerebrospinal fluid (CSF) of HIV-demented (HIV-D) and HIV-nondemented (HIV-ND) patients and studied their affect on neuroglial toxicity. Methods and results Bioplex array showed elevated levels of signatory chemokines or cytokines (IL-6, IFN-γ, CXCL10, MCP-1 and PDGF) in the CSF of HIV-D patients (n = 7) but not in that of HIV-ND patients (n = 7). Among the signatory cytokines and chemokines, CXCL10 was distinctly upregulated in-vitro in HIV-1 (NLENG1)-activated human fetal astrocytes, HIV-1 (Ba-L)-infected macrophages, and HIV-1 (NLENG1)-infected lymphocytes. Virus-infected macrophages also had increased levels of TNF-α. Consistently, human fetal astrocytes treated with HIV-1 and TNF-α induced the signatory molecules. CXCL10 in combination with HIV-1 synergistically enhanced neuronal toxicity and showed chemotactic activity (~ 40 fold) for activated peripheral blood mononuclear cells (PBMC), suggesting the intersection of signaling events imparted by HIV-1 and CXCL10 after binding to their respective surface receptors, CXCR4 and CXCR3, on neurons. Blocking CXCR3 and its downstream MAP kinase (MAPK) signaling pathway suppressed combined CXCL10 and HIV-1-induced neurotoxicity. Bryostatin, a PKC modulator and suppressor of CXCR4, conferred neuroprotection against combined insult with HIV-1 and CXCL10. Bryostatin also suppressed HIV-1 and CXCL10-induced PBMC chemotaxis. Although, therapeutic targeting of chemokines in brain may have adverse consequences on the host, current findings and earlier evidence suggest that CXCL10 could strongly impede neuroinflammation. Conclusion We have demonstrated induction of CXCL10 and other chemokines/cytokines during HIV-1 infection in the brain, as well as synergism of CXCL10 with HIV-1 in neuronal toxicity, which was dampened by bryostatin.
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Affiliation(s)
- Rajeev Mehla
- Department of Pathology, Microbiology & Immunology, University of South Carolina, School of Medicine, Columbia, SC 29209, USA
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19
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Valle-Casuso JC, González-Sánchez A, Medina JM, Tabernero A. HIF-1 and c-Src mediate increased glucose uptake induced by endothelin-1 and connexin43 in astrocytes. PLoS One 2012; 7:e32448. [PMID: 22384254 PMCID: PMC3285680 DOI: 10.1371/journal.pone.0032448] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 01/31/2012] [Indexed: 11/19/2022] Open
Abstract
In previous work we showed that endothelin-1 (ET-1) increases the rate of glucose uptake in astrocytes, an important aspect of brain function since glucose taken up by astrocytes is used to supply the neurons with metabolic substrates. In the present work we sought to identify the signalling pathway responsible for this process in primary culture of rat astrocytes. Our results show that ET-1 promoted an increase in the transcription factor hypoxia-inducible factor-1α (HIF-1α) in astrocytes, as shown in other cell types. Furthermore, HIF-1α-siRNA experiments revealed that HIF-1α participates in the effects of ET-1 on glucose uptake and on the expression of GLUT-1, GLUT-3, type I and type II hexokinase. We previously reported that these effects of ET-1 are mediated by connexin43 (Cx43), the major gap junction protein in astrocytes. Indeed, our results show that silencing Cx43 increased HIF-1α and reduced the effect of ET-1 on HIF-1α, indicating that the effect of ET-1 on HIF-1α is mediated by Cx43. The activity of oncogenes such as c-Src can up-regulate HIF-1α. Since Cx43 interacts with c-Src, we investigated the participation of c-Src in this pathway. Interestingly, both the treatment with ET-1 and with Cx43-siRNA increased c-Src activity. In addition, when c-Src activity was inhibited neither ET-1 nor silencing Cx43 were able to up-regulate HIF-1α. In conclusion, our results suggest that ET-1 by down-regulating Cx43 activates c-Src, which in turn increases HIF-1α leading to the up-regulation of the machinery required to take up glucose in astrocytes. Cx43 expression can be reduced in response not only to ET-1 but also to various physiological and pathological stimuli. This study contributes to the identification of the signalling pathway evoked after Cx43 down-regulation that results in increased glucose uptake in astrocytes. Interestingly, this is the first evidence linking Cx43 to HIF-1, which is a master regulator of glucose metabolism.
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Affiliation(s)
| | | | | | - Arantxa Tabernero
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca, Spain
- * E-mail:
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20
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Tiede LM, Cook EA, Morsey B, Fox HS. Oxygen matters: tissue culture oxygen levels affect mitochondrial function and structure as well as responses to HIV viroproteins. Cell Death Dis 2011; 2:e246. [PMID: 22190005 PMCID: PMC3253381 DOI: 10.1038/cddis.2011.128] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mitochondrial dysfunction is implicated in a majority of neurodegenerative disorders and much study of neurodegenerative disease is done on cultured neurons. In traditional tissue culture, the oxygen level that cells experience is dramatically higher (21%) than in vivo conditions (1-11%). These differences can alter experimental results, especially, pertaining to mitochondria and oxidative metabolism. Our results show that primary neurons cultured at physiological oxygen levels found in the brain showed higher polarization, lower rates of ROS production, larger mitochondrial networks, greater cytoplasmic fractions of mitochondria and larger mitochondrial perimeters than those cultured at higher oxygen levels. Although neurons cultured in either physiological oxygen or atmospheric oxygen exhibit significant increases in mitochondrial reactive oxygen species (ROS) production when treated with the human immunodeficiency virus (HIV) virotoxin trans-activator of transcription, mitochondria of neurons cultured at physiological oxygen underwent depolarization with dramatically increased cell death, whereas those cultured at atmospheric oxygen became hyperpolarized with no increase in cell death. Studies with a second HIV virotoxin, negative regulation factor (Nef), revealed that Nef treatment also increased mitochondrial ROS production for both the oxygen conditions, but resulted in mitochondrial depolarization and increased death only in neurons cultured in physiological oxygen. These results indicate a role for oxidative metabolism in a mechanism of neurotoxicity during HIV infection and demonstrate the importance of choosing the correct, physiological, culture oxygen in mitochondrial studies performed in neurons.
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Affiliation(s)
- L M Tiede
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
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21
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Mehla R, Bivalkar-Mehla S, Chauhan A. A flavonoid, luteolin, cripples HIV-1 by abrogation of tat function. PLoS One 2011; 6:e27915. [PMID: 22140483 PMCID: PMC3227592 DOI: 10.1371/journal.pone.0027915] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 10/27/2011] [Indexed: 12/17/2022] Open
Abstract
Despite the effectiveness of combination antiretroviral treatment (cART) against HIV-1, evidence indicates that residual infection persists in different cell types. Intensification of cART does not decrease the residual viral load or immune activation. cART restricts the synthesis of infectious virus but does not curtail HIV-1 transcription and translation from either the integrated or unintegrated viral genomes in infected cells. All treated patients with full viral suppression actually have low-level viremia. More than 60% of treated individuals also develop minor HIV-1 -associated neurocognitive deficits (HAND) due to residual virus and immune activation. Thus, new therapeutic agents are needed to curtail HIV-1 transcription and residual virus. In this study, luteolin, a dietary supplement, profoundly reduced HIV-1 infection in reporter cells and primary lymphocytes. HIV-1inhibition by luteolin was independent of viral entry, as shown by the fact that wild-type and VSV-pseudotyped HIV-1 infections were similarly inhibited. Luteolin was unable to inhibit viral reverse transcription. Luteolin had antiviral activity in a latent HIV-1 reactivation model and effectively ablated both clade-B- and -C -Tat-driven LTR transactivation in reporter assays but had no effect on Tat expression and its sub-cellular localization. We conclude that luteolin confers anti-HIV-1 activity at the Tat functional level. Given its biosafety profile and ability to cross the blood-brain barrier, luteolin may serve as a base flavonoid to develop potent anti-HIV-1 derivatives to complement cART.
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Affiliation(s)
- Rajeev Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Shalmali Bivalkar-Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
- * E-mail:
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22
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Reijerkerk A, Lakeman KAM, Drexhage JAR, van Het Hof B, van Wijck Y, van der Pol SMA, Kooij G, Geerts D, de Vries HE. Brain endothelial barrier passage by monocytes is controlled by the endothelin system. J Neurochem 2011; 121:730-7. [PMID: 21777246 DOI: 10.1111/j.1471-4159.2011.07393.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Homeostasis of the brain is dependent on the blood-brain barrier (BBB). This barrier tightly regulates the exchange of essential nutrients and limits the free flow of immune cells into the CNS. Perturbations of BBB function and the loss of its immune quiescence are hallmarks of a variety of brain diseases, including multiple sclerosis (MS), vascular dementia, and stroke. In particular, diapedesis of monocytes and subsequent trafficking of monocyte-derived macrophages into the brain are key mediators of demyelination and axonal damage in MS. Endothelin-1 (ET-1) is considered as a potent pro-inflammatory peptide and has been implicated in the development of cardiovascular diseases. Here, we studied the role of different components of the endothelin system, i.e., ET-1, its type B receptor (ET(B)) and endothelin-converting enzyme-1 (ECE-1) in monocyte diapedesis of a human brain endothelial cell barrier. Our pharmacological inhibitory and specific gene knockdown studies point to a regulatory function of these proteins in transendothelial passage of monocytes. Results from this study suggest that the endothelin system is a putative target within the brain for anti-inflammatory treatment in neurological diseases.
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Affiliation(s)
- Arie Reijerkerk
- Blood-brain barrier Research Group, Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands.
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23
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Zhang R, Mehla R, Chauhan A. Perturbation of host nuclear membrane component RanBP2 impairs the nuclear import of human immunodeficiency virus -1 preintegration complex (DNA). PLoS One 2010; 5:e15620. [PMID: 21179483 PMCID: PMC3001881 DOI: 10.1371/journal.pone.0015620] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Accepted: 11/15/2010] [Indexed: 12/12/2022] Open
Abstract
HIV-1 is a RNA virus that requires an intermediate DNA phase via reverse transcription (RT) step in order to establish productive infection in the host cell. The nascent viral DNA synthesized via RT step and the preformed viral proteins are assembled into pre-integration complex (PIC) in the cell cytoplasm. To integrate the viral DNA into the host genome, the PIC must cross cell nuclear membrane through the nuclear pore complex (NPC). RanBP2, also known as Nup358, is a major component of the cytoplasmic filaments that emanates from the nuclear pore complex and has been implicated in various nucleo-cytoplasmic transport pathways including those for HIV Rev-protein. We sought to investigate the role of RanBP2 in HIV-1 replication. In our investigations, we found that RanBP2 depletion via RNAi resulted in profound inhibition of HIV-1 infection and played a pivotal role in the nuclear entry of HIV DNA. More precisely, there was a profound decline in 2-LTR DNA copies (marker for nuclear entry of HIV DNA) and an unchanged level of viral reverse transcription in RanBP2-ablated HIV-infected cells compared to RanBP3-depleted or non-specific siRNA controls. We further demonstrated that the function of Rev was unaffected in RanBP2-depleted latently HIV infected cells (reactivated). We also serendipitously found that RanBP2 depletion inhibited the global ectopic gene expression. In conclusion, RanBP2 is a host factor that is involved in the nuclear import of HIV-1 PIC (DNA), but is not critical to the nuclear export of the viral mRNAs or nucleo-cytoplasmic shuttling of Rev. RanBP2 could be a potential target for efficient inhibition of HIV.
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Affiliation(s)
- Ruonan Zhang
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
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Bivalkar-Mehla S, Vakharia J, Mehla R, Abreha M, Kanwar JR, Tikoo A, Chauhan A. Viral RNA silencing suppressors (RSS): novel strategy of viruses to ablate the host RNA interference (RNAi) defense system. Virus Res 2010; 155:1-9. [PMID: 20951748 DOI: 10.1016/j.virusres.2010.10.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 09/28/2010] [Accepted: 10/05/2010] [Indexed: 12/13/2022]
Abstract
Pathogenic viruses have developed a molecular defense arsenal for their survival by counteracting the host anti-viral system known as RNA interference (RNAi). Cellular RNAi, in addition to regulating gene expression through microRNAs, also serves as a barrier against invasive foreign nucleic acids. RNAi is conserved across the biological species, including plants, animals and invertebrates. Viruses in turn, have evolved mechanisms that can counteract this anti-viral defense of the host. Recent studies of mammalian viruses exhibiting RNA silencing suppressor (RSS) activity have further advanced our understanding of RNAi in terms of host-virus interactions. Viral proteins and non-coding viral RNAs can inhibit the RNAi (miRNA/siRNA) pathway through different mechanisms. Mammalian viruses having dsRNA-binding regions and GW/WG motifs appear to have a high chance of conferring RSS activity. Although, RSSs of plant and invertebrate viruses have been well characterized, mammalian viral RSSs still need in-depth investigations to present the concrete evidences supporting their RNAi ablation characteristics. The information presented in this review together with any perspective research should help to predict and identify the RSS activity-endowed new viral proteins that could be the potential targets for designing novel anti-viral therapeutics.
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Affiliation(s)
- Shalmali Bivalkar-Mehla
- Dept of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29209, United States
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25
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Mehla R, Bivalkar-Mehla S, Zhang R, Handy I, Albrecht H, Giri S, Nagarkatti P, Nagarkatti M, Chauhan A. Bryostatin modulates latent HIV-1 infection via PKC and AMPK signaling but inhibits acute infection in a receptor independent manner. PLoS One 2010; 5:e11160. [PMID: 20585398 PMCID: PMC2886842 DOI: 10.1371/journal.pone.0011160] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Accepted: 05/26/2010] [Indexed: 01/08/2023] Open
Abstract
HIV's ability to establish long-lived latent infection is mainly due to transcriptional silencing in resting memory T lymphocytes and other non dividing cells including monocytes. Despite an undetectable viral load in patients treated with potent antiretrovirals, current therapy is unable to purge the virus from these latent reservoirs. In order to broaden the inhibitory range and effectiveness of current antiretrovirals, the potential of bryostatin was investigated as an HIV inhibitor and latent activator. Bryostatin revealed antiviral activity against R5- and X4-tropic viruses in receptor independent and partly via transient decrease in CD4/CXCR4 expression. Further, bryostatin at low nanomolar concentrations robustly reactivated latent viral infection in monocytic and lymphocytic cells via activation of Protein Kinase C (PKC) -α and -δ, because PKC inhibitors rottlerin and GF109203X abrogated the bryostatin effect. Bryostatin specifically modulated novel PKC (nPKC) involving stress induced AMP Kinase (AMPK) inasmuch as an inhibitor of AMPK, compound C partially ablated the viral reactivation effect. Above all, bryostatin was non-toxic in vitro and was unable to provoke T-cell activation. The dual role of bryostatin on HIV life cycle may be a beneficial adjunct to the treatment of HIV especially by purging latent virus from different cellular reservoirs such as brain and lymphoid organs.
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Affiliation(s)
- Rajeev Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Shalmali Bivalkar-Mehla
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Ruonan Zhang
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Indhira Handy
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Helmut Albrecht
- Department of Medicine, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Shailendra Giri
- Department of Experimental Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Prakash Nagarkatti
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Mitzi Nagarkatti
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Ashok Chauhan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
- * E-mail:
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26
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Butterick TA, Igbavboa U, Eckert GP, Sun GY, Weisman GA, Müller WE, Wood WG. Simvastatin stimulates production of the antiapoptotic protein Bcl-2 via endothelin-1 and NFATc3 in SH-SY5Y cells. Mol Neurobiol 2010; 41:384-91. [PMID: 20369390 PMCID: PMC3075856 DOI: 10.1007/s12035-010-8122-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Accepted: 03/17/2010] [Indexed: 01/11/2023]
Abstract
The use of statins for the prevention or treatment of different neurodegenerative diseases has generated considerable interest albeit with some controversy. Mechanisms of statin-induced neuroprotection are not well understood. Recently, we reported that simvastatin stimulated neuronal gene expression and protein levels of the major antiapoptotic protein Bcl-2 in vivo and in vitro; suppression of Bcl-2 in SH-SY5Y cells reduced simvastatin neuroprotection; effects were independent of cholesterol and other products of the 3-hydroxy-3-methylglutaryl-CoA reductase pathway. Endothelin-1 (ET-1) can increase Bcl-2 abundance via the transcription factor nuclear factor of activated thymocytes (NFATc), and simvastatin was reported to increase ET-1 gene expression. We tested the hypothesis that simvastatin stimulation of Bcl-2 involves up-regulation of ET-1 and binding of NFATc to Bcl-2 promoter sites in SH-SY5Y human neuroblastoma cells. Simvastatin increased both intracellular and secreted ET-1 protein levels. Exogenous ET-1 increased Bcl-2 protein abundance, which was inhibited by ET-1 receptor antagonists. Simvastatin increased translocation of NFATc3 to the nucleus while reducing nuclear NFATc1 and having no effect on NFATc4. Endothelin-1 also increased NFATc3 levels in the nucleus, and this increase was inhibited by ET-1 receptor antagonists. Treatment of cells with simvastatin stimulated binding of NFATc3 to the Bcl-2 promoter. We report novel findings showing that up-regulation of Bcl-2 by simvastatin involves ET-1 and the transcription factor NFATc3. Discovering how statins can selectively alter a specific NFATc isoform that leads to an increase in an antiapoptotic protein will provide a new approach to understanding statin-induced neuroprotection and conditions outside the brain in which apoptosis contributes to pathophysiology.
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Affiliation(s)
- Tammy A. Butterick
- Department of Pharmacology, Geriatric Research Education and Clinical Center, VA Medical Center, University of Minnesota, Minneapolis, MN, USA
| | - Urule Igbavboa
- Department of Pharmacology, Geriatric Research Education and Clinical Center, VA Medical Center, University of Minnesota, Minneapolis, MN, USA
| | - Gunter P. Eckert
- Department of Pharmacology, BiocenterNiederursel, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Grace Y. Sun
- Department of Biochemistry, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, Canada
| | - Gary A. Weisman
- Department of Biochemistry, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, Canada
| | - Walter E. Müller
- Department of Pharmacology, BiocenterNiederursel, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - W. Gibson Wood
- Department of Pharmacology, Geriatric Research Education and Clinical Center, VA Medical Center, University of Minnesota, Minneapolis, MN, USA. Department of Pharmacology, University of Minnesota, 6-120 Jackson Hall, 321 Church Street, SE, Minneapolis, MN 55455, USA
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Abstract
The endothelin receptor-ligand system includes a family of polypeptides and G-protein-coupled receptors, which, in addition to their classic activity in the regulation of vascular tone (both directly and through the control of nitric oxide), were implicated in a wide variety of other key biological processes. In this regard, the endothelins are potent mitogens and motogens for mesenchymal cells, and can induce cell differentiation, increasing both the synthesis and deposition of extracellular matrix components and contractile ability. The endothelins are produced as inactive pre-pro-polypeptides, with gene transcription (as well as the proteolytic processing to mature active forms) under the influence of many factors, including cytokines, hypoxia, biomechanical and shear stress, pathogen products, and many growth factors. These complex regulatory events underlie the association and potential role of endothelins in a number of human diseases affecting many different target organs, including the vasculature (atherosclerosis and hypertension), kidney (renal crisis and chronic kidney disease), heart (coronary heart disease), and lungs (pulmonary fibrosis and pulmonary hypertension). This review focuses on the biochemistry of endothelin and the pathobiology of endothelin in lung fibrosis, with particular emphasis on idiopathic pulmonary fibrosis, and examines the antifibrotic potential of endothelin receptor antagonism.
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Affiliation(s)
- Carmen Fonseca
- Division of Medicine, Department of Inflammation, Centre for Rheumatology and Connective Tissue Diseases, Royal Free and University College Medical School, University College London, Rowland Hill Street, London, UK
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28
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Stavitskaya L, Seminerio MJ, Matthews-Tsourounis MM, Matsumoto RR, Coop A. The effect of the pyridyl nitrogen position in pyridylpiperazine sigma ligands. Bioorg Med Chem Lett 2010; 20:2564-5. [PMID: 20338757 DOI: 10.1016/j.bmcl.2010.02.087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 10/19/2022]
Abstract
A series of pyridylpiperazines was synthesized and analyzed for sigma receptor binding affinity to determine the optimal pyridyl nitrogen position and chain length for the sigma(1) and sigma(2) receptor recognition. The (3-pyridyl)piperazines and (4-pyridyl)piperazines favor sigma(1) receptors, while previously studied (2-pyridyl)piperazines favor sigma(2) receptors.
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Affiliation(s)
- Lidiya Stavitskaya
- Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, Baltimore, MD 21201, USA
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29
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Role of Tat protein in HIV neuropathogenesis. Neurotox Res 2009; 16:205-20. [PMID: 19526283 DOI: 10.1007/s12640-009-9047-8] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 03/09/2009] [Accepted: 03/09/2009] [Indexed: 12/13/2022]
Abstract
The Tat protein of the human immunodeficiency virus (HIV) has been implicated in the pathophysiology of the neurocognitive deficits associated with HIV infection. This is the earliest protein to be produced by the proviral DNA in the infected cell. The protein not only drives the regulatory regions of the virus but may also be actively released from the cell and then interact with the cell surface receptors of other uninfected cells in the brain leading to cellular dysfunction. It may also be taken up by these cells and can then activate a number of host genes. The Tat protein is highly potent and has the unique ability to travel along neuronal pathways. Importantly, its production is not impacted by the use of antiretroviral drugs once the proviral DNA has been formed. This article reviews the pleomorphic actions of Tat protein and the evidence supporting its central role in the neuropathogenesis of the HIV infection.
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30
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Alonso-Villaverde Lozano C. Fisiopatología de la enfermedad cardiovascular en pacientes con VIH. Enferm Infecc Microbiol Clin 2009; 27 Suppl 1:33-9. [DOI: 10.1016/s0213-005x(09)73443-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Herrero-González S, Valle-Casuso JC, Sánchez-Alvarez R, Giaume C, Medina JM, Tabernero A. Connexin43 is involved in the effect of endothelin-1 on astrocyte proliferation and glucose uptake. Glia 2009; 57:222-33. [PMID: 18756537 DOI: 10.1002/glia.20748] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In previous studies, we showed that endothelin-1 increased astrocyte proliferation and glucose uptake. These effects were similar to those observed with other gap junction inhibitors, such as carbenoxolone (CBX). Because 24-h treatment with endothelin-1 or CBX downregulates the expression of connexin43, the main protein forming astrocytic gap junctions, which can also be involved in proliferation, in this study, we addressed the possible role of connexin43 in the effects of endothelin-1. To do so, connexin43 was silenced in astrocytes by siRNA. The knock down of connexin43 increased the rate of glucose uptake, characterized by the upregulation of GLUT-1 and type I hexokinase. Neither endothelin-1 nor CBX were able to further increase the rate of glucose uptake in connexin43-silenced astrocytes. In agreement, no effects of endothelin-1 and CBX on GLUT-1 and type I hexokinase were observed in connexin-43 silenced astrocytes or in astrocytes from connexin43 knock-out (KO) mice. Our previous studies suggested a close relationship between glucose uptake and astrocyte proliferation. Consistent with this, connexin43-silenced astrocytes exhibited an increase in Ki-67, a marker of proliferation. The effects of ET-1 on retinoblastoma phosphorylation on Ser780 and on the upregulation of cyclins D1 and D3 were affected by the levels of connexin43. In conclusion, our results indicate that connexin43 participates in the effects of endothelin-1 on glucose uptake and proliferation in astrocytes. Interestingly, although the rate of growth in connexin43 KO astrocytes has been reported to be reduced, we observed that an acute reduction in connexin43 by siRNA increased proliferation and glucose uptake.
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32
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Ronaldson PT, Persidsky Y, Bendayan R. Regulation of ABC membrane transporters in glial cells: Relevance to the pharmacotherapy of brain HIV-1 infection. Glia 2008; 56:1711-35. [DOI: 10.1002/glia.20725] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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33
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Hembury A, Mabondzo A. Endothelin-1 reduces p-glycoprotein transport activity in an in vitro model of human adult blood-brain barrier. Cell Mol Neurobiol 2008; 28:915-21. [PMID: 18379872 DOI: 10.1007/s10571-008-9277-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 03/13/2008] [Indexed: 02/06/2023]
Abstract
AIMS It is a huge challenge to understand the blood-brain barrier (BBB), which is a key element in neuroinflammation associated with many brain diseases. The BBB also regulates the passage of xenobiotics into the central nervous system (CNS), and therefore influences drug efficacy. This may be due to the presence of ATP binding cassette transporters such as P-glycoprotein (Pgp) on the BBB, which are efflux pumps known to transport many drugs. The peptide endothelin 1 (ET-1) is involved in different kinds of CNS diseases and neuroinflammation, and is known to modulate Pgp transport activity. Although there are data from animal models, data from human models are scarce. We evaluated Pgp expression and transport activity in adult human brain microvascular endothelial cells (HBMECs) when exposing an adult human in vitro BBB model to ET-1. METHODS Adult HBMECs were cocultured with human adult glial cells on a Transwells to mimic blood and CNS compartments. These human in vitro BBBs were exposed for 24 h to 100 nM and 10 nM ET-1. Pgp expression was assessed by flow cytometry and its transport activity by measuring radiolabelled digoxin passage. RESULTS After exposure to ET-1, flow cytometry showed no shift of fluorescence intensity for a Pgp specific antibody. The passage of digoxin increased with a significant decrease of Q ratio for 10 nM ET-1. CONCLUSION Our results show that ET-1 has no effect on Pgp expression of adult HBMECs, but does modulate Pgp transport activity.
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Affiliation(s)
- Alexandra Hembury
- iBiTec-S (Institut de biologie et technologies de Saclay), SPI (Service de Pharmacologie et Immunoanalyse), LEMM (Laboratoire d'Etudes du Métabolisme des Médicaments), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
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Vijaykumar TS, Nath A, Chauhan A. Chloroquine mediated molecular tuning of astrocytes for enhanced permissiveness to HIV infection. Virology 2008; 381:1-5. [PMID: 18789806 DOI: 10.1016/j.virol.2008.07.039] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 06/02/2008] [Accepted: 07/29/2008] [Indexed: 10/21/2022]
Abstract
We report in this study that minimum productive HIV infection in astrocytes (a predominant cell type in brain and persists for the entire life) occurs through endocytosis. The lysosomotropic agent chloroquine enhanced permissiveness of astrocytes to HIV infection possibly by circumventing degradation of endosome-entrapped viral particles. In particular, chloroquine may promote establishment of a stable long term viral reservoir in astrocytes and may eventually facilitate early onset of neurological complications.
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35
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Mercer SL, Shaikh J, Traynor JR, Matsumoto RR, Coop A. Nitrile analogs of meperidine as high affinity and selective sigma-1 receptor ligands. Eur J Med Chem 2008; 43:1304-8. [PMID: 17988766 PMCID: PMC2486414 DOI: 10.1016/j.ejmech.2007.09.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 09/25/2007] [Accepted: 09/27/2007] [Indexed: 11/22/2022]
Abstract
A series of N-substituted-4-cyano-4-phenylpiperidine analogs were synthesized and evaluated for binding affinity at opioid receptors and showed no affinity. The series similarity to previously reported sigma ligands prompted analysis at sigma receptors to determine the SAR for affinity at sigma receptors. Within the N-substituent series the saturated analogs showed increased affinity at both sigma receptors. Optimal chain length in the N-arylalkyl series for sigma(1) and sigma(2) receptors proved to be N-propylphenyl; extension to a four carbon chain dramatically decreased affinity at both receptors. Substituents in the 4-position affect only sigma(1) affinity; no change in affinity at sigma(2) was shown. The N-isobutyl, N-phenylpropyl, and N-benzyl analogs are worth pursuing due to their good affinity and selectivity at the sigma(1) receptor, whereas the N-benzyl analog exhibits the greatest selectivity for sigma(1).
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Affiliation(s)
- Susan L. Mercer
- Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA
| | - Jamaluddin Shaikh
- Department of Pharmacology, University of Mississippi, 303 Faser Hall, University, MS 38677, USA
| | - John R. Traynor
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rae R. Matsumoto
- Department of Pharmacology, University of Mississippi, 303 Faser Hall, University, MS 38677, USA
| | - Andrew Coop
- Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA
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36
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András IE, Rha G, Huang W, Eum S, Couraud PO, Romero IA, Hennig B, Toborek M. Simvastatin protects against amyloid beta and HIV-1 Tat-induced promoter activities of inflammatory genes in brain endothelial cells. Mol Pharmacol 2008; 73:1424-33. [PMID: 18276775 DOI: 10.1124/mol.107.042028] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Increased deposition of amyloid beta (Abeta) is characteristic for normal aging and human immunodeficiency virus-1 (HIV-1)-associated alterations of the central nervous system. In addition, both Abeta and HIV-1 are known to induce cellular oxidative stress and disruption of the blood-brain barrier (BBB). Therefore, we hypothesize that Abeta and HIV-1 protein Tat can potentiate their proinflammatory effects at the brain endothelium level. To address this hypothesis, we studied promoter activity of three proinflammatory genes in an in vitro BBB model of human brain microvascular endothelial cells (HBMEC) cocultured with a human astrocyte cell line producing Tat (SVGA-Tat cells) and exposed to Abeta. Treatment of HBMEC with Abeta(1-40) in the presence of SVGA-Tat cells resulted in a significant up-regulation of E-selectin, CC chemokine ligand-2, and interleukin-6 promoter activities and protein levels compared with the individual effects of Abeta or Tat. In addition, Abeta markedly amplified E-selectin promoter activity in HBMEC cocultured with HIV-1-infected Jurkat T cells. Simvastatin, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, effectively blocked proinflammatory reactions induced by Abeta in cocultures with SVGA-Tat cells or with HIV-1-infected Jurkat cells. The present study indicates that a combined exposure to Abeta and Tat or HIV-1 can synergistically potentiate the expression of inflammatory genes in brain endothelial cells. In addition, simvastatin may provide a beneficial influence by reducing these effects at the BBB level.
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Affiliation(s)
- Ibolya E András
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, 593 Wethington Bldg., 900 S Limestone, Lexington, KY 40536, USA
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