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Coombs NM, Porter JE, Barbagallo M. An exploration of the influencing factors for effective public health messaging during disasters: a scoping review. Public Health 2024; 228:73-81. [PMID: 38325059 DOI: 10.1016/j.puhe.2023.12.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/11/2023] [Accepted: 12/18/2023] [Indexed: 02/09/2024]
Abstract
OBJECTIVES Public health messaging during disasters help to provide knowledge and guidance for preventative behaviours and risk reduction. The aim of this review is to explore how public health messages are currently being provided during disasters and identify what influencing factors contribute to the effectiveness of these messages. STUDY DESIGN Scoping review. METHODS A scoping review was conducted using guidance from Joanna Briggs Methodology for Scoping Reviews. A narrative synthesis was utilised due to the heterogeneity of findings. The review included seventeen sources, addressing a variety of disasters around the globe over the past two decades. RESULTS Three key influencing factors were identified and are illustrated in a concept model called the Audience, Information, Messenger and Mode (AIMM) Public Health Messaging Scale. This conceptual model depicts considerations such as the quantity, quality, and framing of information, the human and technological sources used for delivery and the audience needs and capabilities required for optimal message impact and effectiveness. CONCLUSIONS Public health messages do influence prevention behaviours during disasters, but they must be carefully tailored and delivered to ensure adequate reach, comprehension, and compliance.
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Affiliation(s)
- N M Coombs
- Institute of Health and Wellbeing, Nursing, Federation University Australia, PO Box 3191, Gippsland Mail Centre 3841, Victoria, Australia.
| | - J E Porter
- Institute of Health and Wellbeing, Nursing, Federation University Australia, PO Box 3191, Gippsland Mail Centre 3841, Victoria, Australia.
| | - M Barbagallo
- Institute of Health and Wellbeing, Nursing, Federation University Australia, PO Box 3191, Gippsland Mail Centre 3841, Victoria, Australia.
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Biggane JP, Xu K, Goldenstein BL, Davis KL, Luger EJ, Davis BA, Jurgens CWD, Perez DM, Porter JE, Doze VA. Pharmacological characterization of the α 2A-adrenergic receptor inhibiting rat hippocampal CA3 epileptiform activity: comparison of ligand efficacy and potency. J Recept Signal Transduct Res 2022; 42:580-587. [PMID: 35984443 DOI: 10.1080/10799893.2022.2110896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The mechanism underlying the antiepileptic actions of norepinephrine (NE) is unclear with conflicting results. Our objectives are to conclusively delineate the specific adrenergic receptor (AR) involved in attenuating hippocampal CA3 epileptiform activity and assess compounds for lead drug development. We utilized the picrotoxin model of seizure generation in rat brain slices using electrophysiological recordings. Epinephrine (EPI) reduced epileptiform burst frequency in a concentration-dependent manner. To identify the specific receptor involved in this response, the equilibrium dissociation constants were determined for a panel of ligands and compared with established binding values for α1, α2, and other receptor subtypes. Correlation and slope of unity were found for the α2A-AR, but not other receptors. Effects of different chemical classes of α-AR agonists at inhibiting epileptiform activity by potency (pEC50) and relative efficacy (RE) were determined. Compared with NE (pEC50, 6.20; RE, 100%), dexmedetomidine, an imidazoline (pEC50, 8.59; RE, 67.1%), and guanabenz, a guanidine (pEC50, 7.94; RE, 37.9%), exhibited the highest potency (pEC50). In contrast, the catecholamines, EPI (pEC50, 6.95; RE, 120%) and α-methyl-NE (pEC50, 6.38; RE, 116%) were the most efficacious. These findings confirm that CA3 epileptiform activity is mediated solely by α2A-ARs without activation of other receptor systems. These findings suggest a pharmacotherapeutic target for treating epilepsy and highlight the need for selective and efficacious α2A-AR agonists that can cross the blood-brain barrier.
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Affiliation(s)
- Joseph P Biggane
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Ke Xu
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Brianna L Goldenstein
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Kylie L Davis
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Elizabeth J Luger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Bethany A Davis
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Chris W D Jurgens
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Dianne M Perez
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Van A Doze
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
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Raihan MO, Espelien BM, Hanson C, McGregor BA, Velaris NA, Alvine TD, Al Golovko S, Bradley DS, Nilles M, Glovko MY, Hur J, Porter JE. Characterization of prostanoids response to Bordetella pertussis antigen BscF and Tdap in LPS-challenged monocytes. Prostaglandins Leukot Essent Fatty Acids 2022; 182:102452. [PMID: 35690004 DOI: 10.1016/j.plefa.2022.102452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 12/29/2022]
Abstract
Prostanoids are potent inflammatory mediators that play a regulatory role in the innate immune activation of the adaptive immune response to determine the duration of protection against infection. We aim to quantify the modulation of prostanoids profiles in lipopolysaccharide (LPS)-stimulated THP-1 cells treated with the novel pertussis antigen BscF. We compared the effect with pertussis antigens present in the current Tdap vaccine to understand the immunomodulatory effect that might contribute to the diminished Tdap vaccine effectiveness. The inflammatory challenge with LPS induced a robust elevation of most prostanoid family members compared to the control treatment. Treatment with BscF and Tdap significantly reduced the LPS-stimulated elevation of prostaglandins (PGs) D2, E2, and F2α, as well as thromboxane (TX) A2 levels. An opposite trend was observed for PGI2, as both antigens accelerated the LPS-stimulated upregulation. Further, we quantified cyclooxygenases (COXs) that catalyze the biosynthesis of prostanoids and found that both antigens significantly reduced LPS-stimulated COX-1 and COX-2, demonstrating that the waning of acellular pertussis vaccines' protective immunity may be due to other downstream enzymes not related to COXs. Our present study validates the potential role of BscF as an adjuvant, resulting in the next-generation pertussis vaccine discovery.
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Affiliation(s)
- Md Obayed Raihan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Brenna M Espelien
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Courtney Hanson
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Nathan A Velaris
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Travis D Alvine
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Svetlana Al Golovko
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - David S Bradley
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Matthew Nilles
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Mikhail Y Glovko
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, United States.
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McGregor BA, Schommer J, Guo K, Obayed Raihan M, Ghribi O, Hur J, Porter JE. Corrigendum to “Alpha-Synuclein-induced DNA Methylation and Gene Expression in Microglia” [Neuroscience 468 (2021) 186–198]. Neuroscience 2022; 492:108. [DOI: 10.1016/j.neuroscience.2022.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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McGregor BA, Schommer J, Guo K, Raihan MO, Ghribi O, Hur J, Porter JE. Alpha-Synuclein-induced DNA Methylation and Gene Expression in Microglia. Neuroscience 2021; 468:186-198. [PMID: 34082066 DOI: 10.1016/j.neuroscience.2021.05.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/18/2022]
Abstract
Synucleinopathy disorders are characterized by aggregates of α-synuclein (α-syn), which engage microglia to elicit a neuroinflammatory response. Here, we determined the gene expression and DNA methylation changes in microglia induced by aggregate α-syn. Transgenic murine Thy-1 promoter (mThy1)-Asyn mice overexpressing human α-syn are a model of synucleinopathy. Microglia from 3 and 13-month-old mice were used to isolate nucleic acids for methylated DNA and RNA-sequencing. α-Syn-regulated changes in gene expression and genomic methylation were determined and examined for functional enrichment followed by network analysis to further elucidate possible connections within the data. Microglial DNA isolated from our 3-month cohort had 5315 differentially methylated gene (DMG) changes, while RNA levels demonstrated a change in 119 differentially expressed genes (DEGs) between mThy1-Asyn mice and wild-type littermate controls. The 3-month DEGs and DMGs were highly associated with adhesion and migration signaling, suggesting a phenotypic transition from resting to active microglia. We observed 3742 DMGs and 3766 DEGs in 13-month mThy1-Asyn mice. These genes were often related to adhesion, migration, cell cycle, cellular metabolism, and immune response. Network analysis also showed increased cell mobility and inflammatory functions at 3 months, shifting to cell cycle, immune response, and metabolism changes at 13 months. We observed significant α-syn-induced methylation and gene expression changes in microglia. Our data suggest that α-syn overexpression initiates microglial activation leading to neuroinflammation and cellular metabolic stresses, which is associated with disease progression.
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Affiliation(s)
- Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Jared Schommer
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Kai Guo
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Md Obayed Raihan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Othman Ghribi
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA.
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA.
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Rashmi, More SK, Wang Q, Vomhof‐DeKrey EE, Porter JE, Basson MD. ZINC40099027 activates human focal adhesion kinase by accelerating the enzymatic activity of the FAK kinase domain. Pharmacol Res Perspect 2021; 9:e00737. [PMID: 33715263 PMCID: PMC7955952 DOI: 10.1002/prp2.737] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 12/16/2022] Open
Abstract
Focal adhesion kinase (FAK) regulates gastrointestinal epithelial restitution and healing. ZINC40099027 (Zn27) activates cellular FAK and promotes intestinal epithelial wound closure in vitro and in mice. However, whether Zn27 activates FAK directly or indirectly remains unknown. We evaluated Zn27 potential modulation of the key phosphatases, PTP-PEST, PTP1B, and SHP2, that inactivate FAK, and performed in vitro kinase assays with purified FAK to assess direct Zn27-FAK interaction. In human Caco-2 cells, Zn27-stimulated FAK-Tyr-397 phosphorylation despite PTP-PEST inhibition and did not affect PTP1B-FAK interaction or SHP2 activity. Conversely, in vitro kinase assays demonstrated that Zn27 directly activates both full-length 125 kDa FAK and its 35 kDa kinase domain. The ATP-competitive FAK inhibitor PF573228 reduced basal and ZN27-stimulated FAK phosphorylation in Caco-2 cells, but Zn27 increased FAK phosphorylation even in cells treated with PF573228. Increasing PF573228 concentrations completely prevented activation of 35 kDa FAK in vitro by a normally effective Zn27 concentration. Conversely, increasing Zn27 concentrations dose-dependently activated kinase activity and overcame PF573228 inhibition of FAK, suggesting the direct interactions of Zn27 with FAK may be competitive. Zn27 increased the maximal activity (Vmax ) of FAK. The apparent Km of the substrate also increased under laboratory conditions less relevant to intracellular ATP concentrations. These results suggest that Zn27 is highly potent and enhances FAK activity via allosteric interaction with the FAK kinase domain to increase the Vmax of FAK for ATP. Understanding Zn27 enhancement of FAK activity will be important to redesign and develop a clinical drug that can promote mucosal wound healing.
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Affiliation(s)
- Rashmi
- Department of SurgeryUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
| | - Shyam K. More
- Department of SurgeryUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
| | - Qinggang Wang
- Department of SurgeryUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
| | - Emilie E. Vomhof‐DeKrey
- Department of SurgeryUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
| | - James E. Porter
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
| | - Marc D. Basson
- Department of SurgeryUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
- Department of PathologyUniversity of North Dakota School of Medicine & Health SciencesGrand ForksNDUSA
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McGregor BA, Eid S, Rumora AE, Murdock B, Guo K, de Anda-Jáuregui G, Porter JE, Feldman EL, Hur J. Conserved Transcriptional Signatures in Human and Murine Diabetic Peripheral Neuropathy. Sci Rep 2018; 8:17678. [PMID: 30518872 PMCID: PMC6281650 DOI: 10.1038/s41598-018-36098-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [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] [Received: 06/06/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes. In this study, we employed a systems biology approach to identify DPN-related transcriptional pathways conserved across human and various murine models. Eight microarray datasets on peripheral nerve samples from murine models of type 1 (streptozotocin-treated) and type 2 (db/db and ob/ob) diabetes of various ages and human subjects with non-progressive and progressive DPN were collected. Differentially expressed genes (DEGs) were identified between non-diabetic and diabetic samples in murine models, and non-progressive and progressive human samples using a unified analysis pipeline. A transcriptional network for each DEG set was constructed based on literature-derived gene-gene interaction information. Seven pairwise human-vs-murine comparisons using a network-comparison program resulted in shared sub-networks including 46 to 396 genes, which were further merged into a single network of 688 genes. Pathway and centrality analyses revealed highly connected genes and pathways including LXR/RXR activation, adipogenesis, glucocorticoid receptor signalling, and multiple cytokine and chemokine pathways. Our systems biology approach identified highly conserved pathways across human and murine models that are likely to play a role in DPN pathogenesis and provide new possible mechanism-based targets for DPN therapy.
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Affiliation(s)
- Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, 58202, USA
| | - Stephanie Eid
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Amy E Rumora
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Benjamin Murdock
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Kai Guo
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, 58202, USA
| | - Guillermo de Anda-Jáuregui
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, 58202, USA
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, 58202, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109, USA.
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, 58202, USA.
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McGregor BA, Guo K, Porter JE, Hur J. Systems Approach to Assign Expression Based Signatures to Adrenergic Drugs. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.690.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kai Guo
- Biomedical SciencesUniversity of North DakotaGrand ForksND
| | | | - Junguk Hur
- Biomedical SciencesUniversity of North DakotaGrand ForksND
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Cilz NI, Porter JE, Lei S. A protocol for preparation and transfection of rat entorhinal cortex organotypic cultures for electrophysiological whole-cell recordings. MethodsX 2017; 4:360-371. [PMID: 29071214 PMCID: PMC5651549 DOI: 10.1016/j.mex.2017.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 04/24/2017] [Accepted: 10/11/2017] [Indexed: 01/30/2023] Open
Abstract
Understanding how neuromodulators influence synaptic transmission and intrinsic excitability within the entorhinal cortex (EC) is critical to furthering our understanding of the molecular and cellular aspects of this region. Organotypic cultures can provide a cost-effective means to employ selective molecular biological strategies in elucidating cellular mechanisms of neuromodulation in the EC. We therefore adapted our acute slice model for organotypic culture applications and optimized a protocol for the preparation and biolistic transfection of cultured horizontal EC slices. Here, we present our detailed protocol for culturing EC slices. Using an n-methyl-d-glucamine (NMDG)-containing cutting solution, we obtain healthy EC slice cultures for electrophysiological recordings. We also present our protocol for the preparation of "bullets" carrying one or more constructs and demonstrate successful transfection of EC slices. We build upon previous methods and highlight specific aspects in our method that greatly improved the quality of our results. We validate our methods using immunohistochemical, imaging, and electrophysiological techniques. The novelty of this method is that it provides a description of culturing and transfection of EC neurons for specifically addressing their functionality. This method will enable researchers interested in entorhinal function to quickly adopt a similar slice culture transfection system for their own investigations.
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Affiliation(s)
- Nicholas I Cilz
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - James E Porter
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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Manocha GD, Floden AM, Rausch K, Kulas JA, McGregor BA, Rojanathammanee L, Puig KR, Puig KL, Karki S, Nichols MR, Darland DC, Porter JE, Combs CK. APP Regulates Microglial Phenotype in a Mouse Model of Alzheimer's Disease. J Neurosci 2016; 36:8471-86. [PMID: 27511018 PMCID: PMC4978805 DOI: 10.1523/jneurosci.4654-15.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 05/20/2016] [Accepted: 06/24/2016] [Indexed: 01/13/2023] Open
Abstract
UNLABELLED Prior work suggests that amyloid precursor protein (APP) can function as a proinflammatory receptor on immune cells, such as monocytes and microglia. Therefore, we hypothesized that APP serves this function in microglia during Alzheimer's disease. Although fibrillar amyloid β (Aβ)-stimulated cytokine secretion from both wild-type and APP knock-out (mAPP(-/-)) microglial cultures, oligomeric Aβ was unable to stimulate increased secretion from mAPP(-/-) cells. This was consistent with an ability of oligomeric Aβ to bind APP. Similarly, intracerebroventricular infusions of oligomeric Aβ produced less microgliosis in mAPP(-/-) mice compared with wild-type mice. The mAPP(-/-) mice crossed to an APP/PS1 transgenic mouse line demonstrated reduced microgliosis and cytokine levels and improved memory compared with wild-type mice despite robust fibrillar Aβ plaque deposition. These data define a novel function for microglial APP in regulating their ability to acquire a proinflammatory phenotype during disease. SIGNIFICANCE STATEMENT A hallmark of Alzheimer's disease (AD) brains is the accumulation of amyloid β (Aβ) peptide within plaques robustly invested with reactive microglia. This supports the notion that Aβ stimulation of microglial activation is one source of brain inflammatory changes during disease. Aβ is a cleavage product of the ubiquitously expressed amyloid precursor protein (APP) and is able to self-associate into a wide variety of differently sized and structurally distinct multimers. In this study, we demonstrate both in vitro and in vivo that nonfibrillar, oligomeric forms of Aβ are able to interact with the parent APP protein to stimulate microglial activation. This provides a mechanism by which metabolism of APP results in possible autocrine or paracrine Aβ production to drive the microgliosis associated with AD brains.
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Affiliation(s)
- Gunjan D Manocha
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Angela M Floden
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Keiko Rausch
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Joshua A Kulas
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Lalida Rojanathammanee
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 Thailand
| | - Kelley R Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Kendra L Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Sanjib Karki
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121-4400, and
| | - Michael R Nichols
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121-4400, and
| | - Diane C Darland
- Department of Biology, University of North Dakota, Grand Forks, North Dakota 58202
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Colin K Combs
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203,
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Permpoonputtana K, Porter JE, Govitrapong P. Calcitonin gene-related peptide mediates an inflammatory response in Schwann cells via cAMP-dependent ERK signaling cascade. Life Sci 2015; 144:19-25. [PMID: 26596264 DOI: 10.1016/j.lfs.2015.11.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/14/2015] [Accepted: 11/16/2015] [Indexed: 12/20/2022]
Abstract
AIMS Calcitonin gene-related peptides (CGRP), an endogenous neuropeptide, play an important role in the development of neuroinflammation by acting upon its receptor. The CGRP receptor immunoreactivity was identified on Schwann cells. However the effects of CGRP on Schwann cells are unknown and the exact signaling mechanisms associated with CGRP receptor activation related to Schwann cells inflammatory responses are not well understood. We investigated the effect of CGRP on CGRP receptor activation mediates a proinflammatory signaling response in Schwann cells. MAIN METHODS CGRP-induced ERK-MAPK phosphorylation and proinflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor (TNF-α) expressions were measured by immune blotting. We also used specific antagonist and inhibitors to confirm the exactly signaling pathway including CGRP (8-37), SQ 22536 and H-89. KEY FINDINGS Treatment with CGRP demonstrated a significant generation of IL-1β and IL-6 but not in the level of TNF-α. In addition, there was a temporal increase in the activated form of ERK caused by CGRP that was prevented after pretreatment with CGRP (8-37), SQ 22536 and H-89. Furthermore, use of the CGRP (8-37), ERK inhibitor PD 98059, SQ 22536 or H-89 abolished the CGRP mediated increase in IL-1β. SIGNIFICANCE This investigation provides evidence for a novel CGRP activation on Schwann cells that mediates inflammatory response by increasing of IL-1β and IL-6 expression. CGRP activates the cAMP-PKA-ERK signaling cascade leading to IL-1β production. These results support the notion that CGRP may play a direct role to initiate inflammatory processes in the peripheral nervous system.
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Affiliation(s)
- Kannika Permpoonputtana
- Occupational Therapy Division, Faculty of Physical Therapy, Mahidol University, Nakornpathom 73170, Thailand
| | - James E Porter
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, Grand Forks, ND 58202, USA
| | - Piyarat Govitrapong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand; Center for Neuroscience and Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand.
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Zhang H, Dong H, Cilz NI, Kurada L, Hu B, Wada E, Bayliss DA, Porter JE, Lei S. Neurotensinergic Excitation of Dentate Gyrus Granule Cells via Gαq-Coupled Inhibition of TASK-3 Channels. Cereb Cortex 2014; 26:977-90. [PMID: 25405940 DOI: 10.1093/cercor/bhu267] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [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: 11/14/2022] Open
Abstract
Neurotensin (NT) is a 13-amino acid peptide and serves as a neuromodulator in the brain. Whereas NT has been implicated in learning and memory, the underlying cellular and molecular mechanisms are ill-defined. Because the dentate gyrus receives profound innervation of fibers containing NT and expresses high density of NT receptors, we examined the effects of NT on the excitability of dentate gyrus granule cells (GCs). Our results showed that NT concentration dependently increased action potential (AP) firing frequency of the GCs by the activation of NTS1 receptors resulting in the depolarization of the GCs. NT-induced enhancement of AP firing frequency was not caused indirectly by releasing glutamate, GABA, acetylcholine, or dopamine, but due to the inhibition of TASK-3 K(+) channels. NT-mediated excitation of the GCs was G protein dependent, but independent of phospholipase C, intracellular Ca(2+) release, and protein kinase C. Immunoprecipitation experiment demonstrates that the activation of NTS1 receptors induced the association of Gαq/11 and TASK-3 channels suggesting a direct coupling of Gαq/11 to TASK-3 channels. Endogenously released NT facilitated the excitability of the GCs contributing to the induction of long-term potentiation at the perforant path-GC synapses. Our results provide a cellular mechanism that helps to explain the roles of NT in learning and memory.
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Affiliation(s)
- Haopeng Zhang
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China
| | - Hailong Dong
- Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China
| | - Nicholas I Cilz
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Lalitha Kurada
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Binqi Hu
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Etsuko Wada
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, Tokyo, Japan
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - James E Porter
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Saobo Lei
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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Nopparat C, Porter JE, Ebadi M, Govitrapong P. 1-Methyl-4-phenylpyridinium-induced cell death via autophagy through a Bcl-2/Beclin 1 complex-dependent pathway. Neurochem Res 2013; 39:225-32. [PMID: 24326530 DOI: 10.1007/s11064-013-1208-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/29/2013] [Accepted: 11/25/2013] [Indexed: 01/07/2023]
Abstract
Several lines of evidence suggest that the mechanism underlying drug-induced neuronal apoptosis is initiated by the increased production of reactive oxygen species (ROS). 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin, has been shown to initiate an apoptotic cascade by increasing ROS in the dopaminergic neurons of the substantia nigra, leading to the morphological and physiological features associated with Parkinson's disease. Recently, it has been reported that autophagy, a type of programmed cell death independent of the apoptotic cascade, also plays a role in neuronal damage. Although autophagy is negatively regulated by the mammalian target of rapamycin receptor (mTOR), there is some evidence showing a novel function for the anti-apoptotic protein Bcl-2. Bcl-2 is proposed to play a role in negatively regulating autophagy by blocking an essential protein in the signaling pathway, Beclin 1. Nevertheless, it is unclear whether autophagy is also correlated with apoptotic signaling in 1-methyl-4-phenylpyridinium (MPP(+)) toxicity. Therefore, we hypothesized that the MPP(+) toxicity generally associated with initiating the apoptotic signaling cascade also increases an autophagic phenotype in neuronal cells. Using the SK-N-SH dopaminergic cell lines, we demonstrate that MPP(+) increases the expression of microtubule-associated protein light chain 3 (LC3-II), an autophagosome membrane marker and the mTOR signaling pathway, and Beclin 1 while decreasing the Bcl-2 levels. Moreover, these expressions correlate with a decreased binding ratio between Bcl-2 and Beclin 1, in effect limiting the regulation of the downstream autophagic markers, such as LC3-II. Our results indicate that MPP(+) can induce autophagy in SK-N-SH cells by decreasing the Bcl-2/Beclin 1 complex.
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Affiliation(s)
- Chutikorn Nopparat
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand
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15
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Grisanti LA, Kurada L, Cilz NI, Porter JE, Lei S. Phospholipase C not protein kinase C is required for the activation of TRPC5 channels by cholecystokinin. Eur J Pharmacol 2012; 689:17-24. [PMID: 22683873 DOI: 10.1016/j.ejphar.2012.05.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 05/12/2012] [Accepted: 05/24/2012] [Indexed: 01/09/2023]
Abstract
Cholecystokinin (CCK) is one of the most abundant neuropeptides in the brain where it interacts with two G protein-coupled receptors (CCK1 and CCK2). Both types of CCK receptors are coupled to G(q/11) proteins resulting in increased function of phospholipase C (PLC) pathway. Whereas CCK has been suggested to increase neuronal excitability in the brain via activation of cationic channels, the types of cationic channels have not yet been identified. Here, we co-expressed CCK2 receptors and TRPC5 channels in human embryonic kidney (HEK) 293 cells and studied the effects of CCK on TRPC5 channels using patch-clamp techniques. Our results demonstrate that activation of CCK2 receptors robustly potentiates the function of TRPC5 channels. CCK-induced activation of TRPC5 channels requires the functions of G-proteins and PLC and depends on extracellular Ca(2+). The activation of TRPC5 channels mediated by CCK2 receptors is independent of IP(3) receptors and protein kinase C. CCK-induced opening of TRPC5 channels is not store-operated because application of thapsigargin to deplete intracellular Ca(2+) stores failed to alter CCK-induced TRPC5 channel currents significantly. Bath application of CCK also significantly increased the open probability of TRPC5 single channel currents in cell-attached patches. Because CCK exerts extensive effects in the brain, our results may provide a novel mechanism to explain its roles in modulating neuronal excitability.
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Affiliation(s)
- Laurel A Grisanti
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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16
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Xiao Z, Jaiswal MK, Deng PY, Matsui T, Shin HS, Porter JE, Lei S. Requirement of phospholipase C and protein kinase C in cholecystokinin-mediated facilitation of NMDA channel function and anxiety-like behavior. Hippocampus 2011; 22:1438-50. [PMID: 22072552 DOI: 10.1002/hipo.20984] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2011] [Indexed: 01/07/2023]
Abstract
Although cholecystokinin (CCK) has long been known to exert anxiogenic effects in both animal anxiety models and humans, the underlying cellular and molecular mechanisms are ill-defined. CCK interacts with CCK-1 and CCK-2 receptors resulting in up-regulation of phospholipase C (PLC) and protein kinase C (PKC). However, the roles of PLC and PKC in CCK-mediated anxiogenic effects have not been determined. We have shown previously that CCK facilitates glutamate release in the hippocampus especially at the synapses formed by the perforant path and dentate gyrus granule cells via activations of PLC and PKC. Here we further demonstrated that CCK enhanced NMDA receptor function in dentate gyrus granule cells via activation of PLC and PKC pathway. At the single-channel level, CCK increased NMDA single-channel open probability and mean open time, reduced the mean close time, and had no effects on the conductance of NMDA channels. Because elevation of glutamatergic functions results in anxiety, we explored the roles of PLC and PKC in CCK-induced anxiogenic actions using the Vogel Conflict Test (VCT). Our results from both pharmacological approach and knockout mice demonstrated that microinjection of CCK into the dentate gyrus concentration-dependently increased anxiety-like behavior via activation of PLC and PKC. Our results provide a novel unidentified signaling mechanism whereby CCK increases anxiety.
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Affiliation(s)
- Zhaoyang Xiao
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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17
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Grisanti LA, Woster AP, Dahlman J, Sauter ER, Combs CK, Porter JE. α1-adrenergic receptors positively regulate Toll-like receptor cytokine production from human monocytes and macrophages. J Pharmacol Exp Ther 2011; 338:648-57. [PMID: 21571945 DOI: 10.1124/jpet.110.178012] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Catecholamines released from the sympathetic nervous system in response to stress or injury affect expression of inflammatory cytokines generated by immune cells. α(1)-Adrenergic receptors (ARs) are expressed on innate immune cell populations, but their subtype expression patterns and signaling characteristics are not well characterized. Primary human monocytes, a human monocytic cell line, and monocyte-derived macrophage cells were used to measure expression of the proinflammatory mediator interleukin (IL)-1β responding to lipopolysaccharide (LPS) in the presence or absence of α(1)-AR activation. Based on our previous findings, we hypothesized that α(1)-AR stimulation on innate immune cells positively regulates LPS-initiated IL-1β production. IL-1β production in response to LPS was synergistically higher for both monocytes and macrophages in the presence of the selective α(1)-AR agonist (R)-(-)-phenylephrine hydrochloride (PE). This synergistic IL-1β response could be blocked with a selective α(1)-AR antagonist as well as inhibitors of protein kinase C (PKC). Radioligand binding studies characterized a homogenous α(1B)-AR subtype population on monocytes, which changed to a heterogeneous receptor subtype expression pattern when differentiated to macrophages. Furthermore, increased p38 mitogen-activated protein kinase (MAPK) activation was observed only with concurrent PE and LPS stimulation, peaking after 120 and 30 min in monocytes and macrophages, respectively. Blocking the PKC/p38 MAPK signaling pathway in both innate immune cell types inhibited the synergistic IL-1β increase observed with concurrent PE and LPS treatments. This study characterizes α(1)-AR subtype expression on both human monocyte and macrophage cells and illustrates a mechanism by which increased IL-1β production can be modulated by α(1)-AR input.
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Affiliation(s)
- Laurel A Grisanti
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58202-9037, USA
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18
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Grisanti L, Porter JE. Novel GRK and β‐arrestin isotype regulation of Toll‐like receptor 4 signaling. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1007.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laurel Grisanti
- Pharmacology, Physiology and TherapeuticsUniversity of North DakotaGrand ForksND
| | - James E Porter
- Pharmacology, Physiology and TherapeuticsUniversity of North DakotaGrand ForksND
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19
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Abstract
The sympathetic nervous system regulates human immune system functions through epinephrine (Epi) and norepinephrine (NE) activation of adrenergic receptors (AR) expressed on immunocompetent cell populations. The anti-inflammatory effects that are most often attributed to increased sympathetic activity have been shown to occur through β2- and α2-AR stimulation. However, dichotomous AR effects on immune system function are becoming increasingly apparent. Reports of α1-AR expression on immune cell populations have been conflicting due to a lack of specific antibodies or subtype-selective receptor ligands. This has made α1-AR identification difficult and further characterization of α1-AR subtype expression limited. Nevertheless, there is some evidence suggesting an induction of α1-AR expression on immunocompetent cells under certain physiological conditions and disease states. Also, the function of α1-AR activation to modulate immune responses is just beginning to emerge in the literature. Changes in the secretion of inflammatory mediators as well as increased cell migration and differentiation have been described following α1-AR stimulation on immunocompetent cells. These observations demonstrate the significance of α1-AR activity in immune cell biology and emphasize the importance for understanding α1-AR effects on the immune system.
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Affiliation(s)
- Laurel A Grisanti
- Department of Pharmacology, Physiology, and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
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20
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Abstract
Methamphetamine (METH) is a common drug of abuse that induces toxicity in the central nervous system and is connected to neurological disorders such as Parkinson's disease. METH neurotoxicity is induced by reactive oxygen species (ROS) production and apoptosis. Moreover, autophagy is an alternative to cell death and a means for eliminating dysfunctional organelles. In other cases, autophagy can end up in cell death. Nonetheless, it is not clear whether autophagy is also correlated with apoptotic signaling in drug-induced neurotoxicity. Therefore, we hypothesized that METH-generated toxicity associated with initiating the apoptotic signaling cascade can also increase the autophagic phenotype in neuronal cells. Using the SK-N-SH dopaminergic cell line as our model system, we found that METH-induced autophagy by inhibiting dissociation of Bcl-2/Beclin 1 complex and its upstream pathway that thereby led to cell death. We uncovered a novel function for the anti-apoptotic protein Bcl-2, as it played a role in negatively regulating autophagy by blocking an essential protein in the signaling pathway, Beclin 1. Furthermore, Bcl-2 was activated by c-Jun N-terminal kinase 1 (JNK 1), which is upstream of Bcl-2 phosphorylation, to induce Bcl-2/Beclin 1 dissociation. Furthermore, we demonstrated a novel role for melatonin in protecting cells from autophagic cell death triggered by the Bcl-2/Beclin 1 pathway by inhibiting the activation of the JNK 1, Bcl-2 upstream pathway. This study provides information regarding the link between apoptosis and autophagy signaling, which could lead to the development of therapeutic strategies that exploit the neurotoxicity of drugs of abuse.
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Affiliation(s)
- Chutikorn Nopparat
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand
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21
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Slusser AM, Porter JE. Peroxiredoxin, a mitochondrial‐specific peroxidase, as a possible key regulator of the β‐adrenergic receptor anti‐apoptotic pathway. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.703.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andrea M. Slusser
- Pharmacology, Physiology & TherapeuticsUniversity of North DakotaGrand ForksND
| | - James E. Porter
- Pharmacology, Physiology & TherapeuticsUniversity of North DakotaGrand ForksND
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22
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Grisanti LA, Porter JE. Synergistic α1‐adrenergic receptor mediated increases in IL‐1β from lipopolysaccharide‐challenged human monocytes is β‐arrestin 1‐dependent and NF‐κB‐independent. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.586.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laurel A Grisanti
- Pharmacology, Physiology and TherapeuticsUniversity of North DakotaGrand ForksND
| | - James E Porter
- Pharmacology, Physiology and TherapeuticsUniversity of North DakotaGrand ForksND
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23
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Grisanti LA, Evanson J, Marchus E, Jorissen H, Woster AP, DeKrey W, Sauter ER, Combs CK, Porter JE. Pro-inflammatory responses in human monocytes are beta1-adrenergic receptor subtype dependent. Mol Immunol 2010; 47:1244-54. [PMID: 20116105 DOI: 10.1016/j.molimm.2009.12.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 12/23/2009] [Indexed: 12/20/2022]
Abstract
Stress induced circulating catecholamines are hypothesized to selectively activate adrenergic receptors (ARs) on immunocompetent cells modulating their inflammatory response to trauma or environmental toxins. We characterized changes in expression of a pro-inflammatory cytokine modulated by beta-AR activation in human primary and immortalized monocytes that had been simultaneously stimulated with lipopolysaccharide (LPS). Results from cytokine antibody arrays demonstrated that half-maximal effective concentrations of the selective beta-AR agonist isoproterenol (Iso) qualitatively increased LPS-mediated expression of the soluble cytokine, interleukin-1beta (IL-1beta). Semi-quantitative immunoblot techniques confirmed a synergistic increase of IL-1beta production in both LPS stimulated THP-1 cells and primary human monocytes co-incubated with Iso. Immunoblot techniques as well as radioligand binding studies were also used to characterize the heterogeneous expression of beta(1)- and beta(2)-AR subtypes on THP-1 cells. beta-AR activation is classically associated with generation of cAMP in many tissues and cell types. Therefore, using the method of Schild, we generated Iso concentration-response curves in the presence of fixed subtype-selective beta-AR antagonist concentrations to demonstrate that beta(1)-AR activation was exclusively linked with the generation of cAMP in THP-1 cells. Furthermore, use of a selective kinase inhibitor demonstrated that Iso potentiated the expression of soluble IL-1beta through activation of cAMP-dependent protein kinase A. Finally, discriminating concentrations of subtype-selective beta-AR antagonists revealed that beta(1)-AR stimulation alone accounted for the synergistic production of IL-1beta in LPS stimulated monocytes co-incubated with Iso. These results demonstrate a unique synergistic pro-inflammatory response mediated through a beta(1)-AR cAMP-dependent mechanism in LPS-challenged monocytic cells.
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Affiliation(s)
- Laurel A Grisanti
- Department of Pharmacology, Physiology and Therapeutics, The University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202-9037, USA
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24
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25
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Deng PY, Xiao Z, Yang C, Rojanathammanee L, Grisanti L, Watt J, Geiger JD, Liu R, Porter JE, Lei S. GABA(B) receptor activation inhibits neuronal excitability and spatial learning in the entorhinal cortex by activating TREK-2 K+ channels. Neuron 2009; 63:230-43. [PMID: 19640481 DOI: 10.1016/j.neuron.2009.06.022] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 02/23/2009] [Accepted: 06/29/2009] [Indexed: 11/25/2022]
Abstract
The entorhinal cortex (EC) is regarded as the gateway to the hippocampus and thus is essential for learning and memory. Whereas the EC expresses a high density of GABA(B) receptors, the functions of these receptors in this region remain unexplored. Here, we examined the effects of GABA(B) receptor activation on neuronal excitability in the EC and spatial learning. Application of baclofen, a specific GABA(B) receptor agonist, inhibited significantly neuronal excitability in the EC. GABA(B) receptor-mediated inhibition in the EC was mediated via activating TREK-2, a type of two-pore domain K(+) channels, and required the functions of inhibitory G proteins and protein kinase A pathway. Depression of neuronal excitability in the EC underlies GABA(B) receptor-mediated inhibition of spatial learning as assessed by Morris water maze. Our study indicates that GABA(B) receptors exert a tight control over spatial learning by modulating neuronal excitability in the EC.
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Affiliation(s)
- Pan-Yue Deng
- Department of Pharmacology, Physiology, and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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26
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Grisanti LA, Porter JE. α
1
‐Adrenergic Receptor Modulation of LPS Induced Inflammation in Normal and PMA Differentiated THP‐1 Cells. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.941.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laurel A Grisanti
- Pharmacology, Physiology and TherapeuticsUniversity of North Dakota School of Medicine and Health SciencesGrand ForksND
| | - James E Porter
- Pharmacology, Physiology and TherapeuticsUniversity of North Dakota School of Medicine and Health SciencesGrand ForksND
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27
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Grisanti LA, Evanson J, Jorissen H, Porter JE. β
1
‐Adrenergic Receptor Activation Potentiates a Pro‐Inflammatory Response in Human Monocytes. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.941.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laurel A Grisanti
- Pharmacology, Physiology and TherapeuticsUniversity of North Dakota School of Medicine and Health SciencesGrand ForksND
| | - Janel Evanson
- Pharmacology, Physiology and TherapeuticsUniversity of North Dakota School of Medicine and Health SciencesGrand ForksND
| | - Heather Jorissen
- Pharmacology, Physiology and TherapeuticsUniversity of North Dakota School of Medicine and Health SciencesGrand ForksND
| | - James E Porter
- Pharmacology, Physiology and TherapeuticsUniversity of North Dakota School of Medicine and Health SciencesGrand ForksND
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28
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Xiao Z, Deng PY, Rojanathammanee L, Yang C, Grisanti L, Permpoonputtana K, Weinshenker D, Doze VA, Porter JE, Lei S. Noradrenergic depression of neuronal excitability in the entorhinal cortex via activation of TREK-2 K+ channels. J Biol Chem 2009; 284:10980-91. [PMID: 19244246 DOI: 10.1074/jbc.m806760200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The entorhinal cortex is closely associated with the consolidation and recall of memories, Alzheimer disease, schizophrenia, and temporal lobe epilepsy. Norepinephrine is a neurotransmitter that plays a significant role in these physiological functions and neurological diseases. Whereas the entorhinal cortex receives profuse noradrenergic innervations from the locus coeruleus of the pons and expresses high densities of adrenergic receptors, the function of norepinephrine in the entorhinal cortex is still elusive. Accordingly, we examined the effects of norepinephrine on neuronal excitability in the entorhinal cortex and explored the underlying cellular and molecular mechanisms. Application of norepinephrine-generated hyperpolarization and decreased the excitability of the neurons in the superficial layers with no effects on neuronal excitability in the deep layers of the entorhinal cortex. Norepinephrine-induced hyperpolarization was mediated by alpha(2A) adrenergic receptors and required the functions of Galpha(i) proteins, adenylyl cyclase, and protein kinase A. Norepinephrine-mediated depression on neuronal excitability was mediated by activation of TREK-2, a type of two-pore domain K(+) channel, and mutation of the protein kinase A phosphorylation site on TREK-2 channels annulled the effects of norepinephrine. Our results indicate a novel action mode in which norepinephrine depresses neuronal excitability in the entorhinal cortex by disinhibiting protein kinase A-mediated tonic inhibition of TREK-2 channels.
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Affiliation(s)
- Zhaoyang Xiao
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota 58203
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29
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Hillman KL, Lei S, Doze VA, Porter JE. Alpha-1A adrenergic receptor activation increases inhibitory tone in CA1 hippocampus. Epilepsy Res 2009; 84:97-109. [PMID: 19201164 DOI: 10.1016/j.eplepsyres.2008.12.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [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: 08/26/2008] [Revised: 12/19/2008] [Accepted: 12/27/2008] [Indexed: 11/19/2022]
Abstract
The endogenous catecholamine norepinephrine (NE) exhibits anti-epileptic properties, however it is not well understood which adrenergic receptor (AR) mediates this effect. The aim of this study was to investigate alpha(1)-adrenergic receptor activation in region CA1 of the hippocampus, a subcortical structure often implicated in temporal lobe epilepsies. Using cell-attached and whole-cell recordings in rat hippocampal slices, we confirmed that selective alpha(1)-AR activation increases action potential firing in a subpopulation of CA1 interneurons. We found that this response is mediated via the alpha(1A)-AR subtype, initiated by sodium influx, and appears independent of second messenger signaling. In CA1 pyramidal cells, alpha(1A)-AR activation decreases activity due to increased pre-synaptic GABA and somatostatin release. Examination of post-synaptic receptor involvement revealed that while GABA(A) receptors mediate the majority of alpha(1A)-adrenergic effects on CA1 pyramidal cells, significant contributions are also made by GABA(B) and somatostatin receptors. Finally, to test whether alpha(1A)-AR activation could have potential therapeutic implications, we performed AR agonist challenges using two in vitro epileptiform models. When GABA(A) receptors were available, alpha(1A)-AR activation significantly decreased epileptiform bursting in CA1. Together, our findings directly link stimulation of the alpha(1A)-AR subtype to release of GABA and somatostatin at the single cell level and suggest that alpha(1A)-AR activation may represent one mechanism by which NE exerts anti-epileptic effects within the hippocampus.
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Affiliation(s)
- Kristin L Hillman
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58203, United States
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30
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Rojanathammanee L, Harmon EB, Grisanti LA, Govitrapong P, Ebadi M, Grove BD, Miyagi M, Porter JE. The 27-kDa heat shock protein confers cytoprotective effects through a beta 2-adrenergic receptor agonist-initiated complex with beta-arrestin. Mol Pharmacol 2009; 75:855-65. [PMID: 19176359 DOI: 10.1124/mol.108.053397] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heat shock proteins represent an emerging model for the coordinated, multistep regulation of apoptotic signaling events. Although certain aspects of the biochemistry associated with heat shock protein cytoprotective effects are known, little information is found describing the regulation of heat shock protein responses to harmful stimuli. During screening for noncanonical beta adrenergic receptor signaling pathways in human urothelial cells, using mass spectroscopy techniques, an agonist-dependent interaction with beta-arrestin and the 27-kDa heat shock protein was observed in vitro. Formation of this beta-arrestin/Hsp27 complex in response to the selective beta adrenergic receptor agonist isoproterenol, was subsequently confirmed in situ by immunofluorescent colocalization studies. Radioligand binding techniques characterized a homogeneous population of the beta2 adrenergic receptor subtype expressed on these cells. Using terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling, immunoblot analysis and quantitation of caspase-3 activity to detect apoptosis, preincubation of these cells with isoproterenol was found to be sufficient for protection against programmed cell death initiated by staurosporine. RNA interference strategies confirmed the necessity for Hsp27 as well as both beta-arrestin isoforms to confer this cytoprotective consequence of beta adrenergic receptor activation in this cell model. As a result, these studies represent the first description of an agonist-dependent relationship between a small heat shock protein and beta-arrestin to form a previously unknown antiapoptotic "signalosome."
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Affiliation(s)
- Lalida Rojanathammanee
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, Grand Forks, ND 58202-9037, USA
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Abstract
Whereas the entorhinal cortex (EC) receives noradrenergic innervations from the locus coeruleus of the pons and expresses adrenergic receptors, the function of norepinephrine (NE) in the EC is still elusive. We examined the effects of NE on GABA(A) receptor-mediated synaptic transmission in the superficial layers of the EC. Application of NE dose-dependently increased the frequency and amplitude of spontaneous inhibitory postsynaptic currents (IPSCs) recorded from the principal neurons in layer II/III through activation of alpha(1) adrenergic receptors. NE increased the frequency and not the amplitude of miniature IPSCs (mIPSCs) recorded in the presence of TTX, suggesting that NE increases presynaptic GABA release with no effects on postsynaptic GABA(A) receptors. Application of Ca(2+) channel blockers (Cd(2+) and Ni(2+)), omission of Ca(2+) in the extracellular solution, or replacement of extracellular Na(+) with N-methyl-D-glucamine (NMDG) failed to alter NE-induced increase in mIPSC frequency, suggesting that Ca(2+) influx through voltage-gated Ca(2+) or other cationic channels is not required. Application of BAPTA-AM, thapsigargin, and ryanodine did not change NE-induced increase in mIPSC frequency, suggesting that Ca(2+) release from intracellular stores is not necessary for NE-induced increase in GABA release. Whereas alpha(1) receptors are coupled to G(q/11) resulting in activation of the phospholipase C (PLC) pathway, NE-mediated facilitation of GABAergic transmission was independent of PLC, protein kinase C, and tyrosine kinase activities. Our results suggest that NE-mediated facilitation of GABAergic function contributes to its antiepileptic effects in the EC.
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Affiliation(s)
- Saobo Lei
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA.
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Deng PY, Poudel SKS, Rojanathammanee L, Porter JE, Lei S. Serotonin Inhibits Neuronal Excitability by Activating Two-Pore Domain K+ Channels in the Entorhinal Cortex. Mol Pharmacol 2007; 72:208-18. [PMID: 17452494 DOI: 10.1124/mol.107.034389] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [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] [Indexed: 01/13/2023] Open
Abstract
The entorhinal cortex (EC) is regarded as the gateway to the hippocampus; the superficial layers (layers I-III) of the EC convey the cortical input projections to the hippocampus, whereas deep layers of the EC relay hippocampal output projections back to the superficial layers of the EC or to other cortical regions. The superficial layers of the EC receive strong serotonergic projections from the raphe nuclei. However, the function of serotonin in the EC is still elusive. In the present study, we examined the molecular and cellular mechanisms underlying serotonin-mediated inhibition of the neuronal excitability in the superficial layers (layers II and III) of the EC. Application of serotonin inhibited the excitability of stellate and pyramidal neurons in the superficial layers of the EC by activating the TWIK-1 type of the two-pore domain K(+) channels. The effects of 5-HT were mediated via 5-HT(1A) receptors and required the function of Galpha(i3) subunit and protein kinase A. Serotonin-mediated inhibition of EC activity resulted in an inhibition of hippocampal function. Our study provides a cellular mechanism that might at least partially explain the roles of serotonin in many physiological functions and neurological diseases.
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Affiliation(s)
- Pan-Yue Deng
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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Jurgens CWD, Hammad HM, Lichter JA, Boese SJ, Nelson BW, Goldenstein BL, Davis KL, Xu K, Hillman KL, Porter JE, Doze VA. Alpha2A adrenergic receptor activation inhibits epileptiform activity in the rat hippocampal CA3 region. Mol Pharmacol 2007; 71:1572-81. [PMID: 17341653 DOI: 10.1124/mol.106.031773] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [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] [Indexed: 11/22/2022] Open
Abstract
Norepinephrine has potent antiepileptic properties, the pharmacology of which is unclear. Under conditions in which GABAergic inhibition is blocked, norepinephrine reduces hippocampal cornu ammonis 3 (CA3) epileptiform activity through alpha(2) adrenergic receptor (AR) activation on pyramidal cells. In this study, we investigated which alpha(2)AR subtype(s) mediates this effect. First, alpha(2)AR genomic expression patterns of 25 rat CA3 pyramidal cells were determined using real-time single-cell reverse transcription-polymerase chain reaction, demonstrating that 12 cells expressed alpha(2A)AR transcript; 3 of the 12 cells additionally expressed mRNA for alpha(2C)AR subtype and no cells possessing alpha(2B)AR mRNA. Hippocampal CA3 epileptiform activity was then examined using field potential recordings in brain slices. The selective alphaAR agonist 6-fluoronorepinephrine caused a reduction of CA3 epileptiform activity, as measured by decreased frequency of spontaneous epileptiform bursts. In the presence of betaAR blockade, concentration-response curves for AR agonists suggest that an alpha(2)AR mediates this response, as the rank order of potency was 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine (UK-14304) >or= epinephrine >6-fluoronorepinephrine > norepinephrine >>> phenylephrine. Finally, equilibrium dissociation constants (K(b)) of selective alphaAR antagonists were functionally determined to confirm the specific alpha(2)AR subtype inhibiting CA3 epileptiform activity. Apparent K(b) values calculated for atipamezole (1.7 nM), MK-912 (4.8 nM), BRL-44408 (15 nM), yohimbine (63 nM), ARC-239 (540 nM), prazosin (4900 nM), and terazosin (5000 nM) correlated best with affinities previously determined for the alpha(2A)AR subtype (r = 0.99, slope = 1.0). These results suggest that, under conditions of impaired GABAergic inhibition, activation of alpha(2A)ARs is primarily responsible for the antiepileptic actions of norepinephrine in the rat hippocampal CA3 region.
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Affiliation(s)
- Chris W D Jurgens
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037, USA
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Hillman KL, Doze VA, Porter JE. Alpha1A-adrenergic receptors are functionally expressed by a subpopulation of cornu ammonis 1 interneurons in rat hippocampus. J Pharmacol Exp Ther 2007; 321:1062-8. [PMID: 17337632 DOI: 10.1124/jpet.106.119297] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [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] [Indexed: 11/22/2022] Open
Abstract
The importance of adrenergic receptors (ARs) in the hippocampus has generally focused on betaARs; however, interest is growing in hippocampal alphaARs given their purported neuroprotective role. We have previously reported alpha(1)AR transcripts in a subpopulation of cornu ammonis 1 (CA1) interneurons. The goal of this study was to identify the specific alpha(1)AR subtype (alpha(1A), alpha(1B), alpha(1D)) functionally expressed by these cells. Using cell-attached recordings to measure action potential frequency changes, concentration-response curves for the selective alpha(1)AR agonist phenylephrine (PE) were generated in the presence of competitive subtype-selective alpha(1)AR antagonists. Schild regression analysis was then used to estimate equilibrium dissociation constants (K(b)) for each receptor antagonist in our system. The selective alpha(1A)AR antagonists, 5-methylurapidil and WB-4101 [2-[(2,6-dimethoxyphenoxyethyl)aminomethyl]-1,4-benzodioxane hydrochloride], produced consecutive rightward shifts in the concentration-response curve for PE when used at discriminating, nanomolar concentrations. Calculated K(b) values for 5-methylurapidil (10 nM) and WB-4101 (5 nM) correlate to previously published affinity values for these antagonists at the alpha(1A)AR. The selective alpha(1B)AR antagonist L-765,314 [(2S)-4-(4-amino-6,7-dimethoxy-2-quinazolinyl)-2-[[(1,1-dimethylethyl)amino]carbonyl]-1-piperazinecarboxylic acid], as well as the selective alpha(1D)AR antagonist BMY7378 [8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride], produced significant rightward shifts in the concentration-response curve for PE only when used at nondistinguishing, micromolar concentrations. Calculated K(b) values for L-765,314 (794 nM) and BMY7378 (316 nM) do not agree with affinity values for these antagonists at the alpha(1B) or alpha(1D)AR, respectively. Rather, these K(b) values more closely match equilibrium dissociation constants estimated for these compounds when used to identify alpha(1A)AR subtypes. Together, our results provide strong evidence to support functional expression of alpha(1A)ARs in a subpopulation of CA1 interneurons.
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Affiliation(s)
- Kristin L Hillman
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Stop 9037, Grand Forks, North Dakota 58202-9037, USA
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Abstract
This article examines C. R. Snyder's (1994, 2000a) theory of hope and its application for understanding suicide. Strengths, weaknesses, and gaps in the suicide literature are outlined, and A. T. Beck's theory of hopelessness is compared with Snyder's hope theory. Hope theory constructs are used to examine the relationship of suicide to hope/hopelessness, goals, pathways thinking, and agency thinking. This critical review is intended to broaden our theoretical understanding of suicide and is meant to form the basis for future empirical investigation of suicide-related behavior using the framework of hope theory. Implications for suicide prevention programs and approaches to treating suicidal individuals are outlined.
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Affiliation(s)
- Parveen K Grewal
- Department of Psychology, University of Windsor, Windsor, Ontario, Canada N9B 3P4. parveengrewal@hotmail .com
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Banerjee S, Evanson J, Harris E, Lowe SL, Speth RC, Thomasson KA, Porter JE. Erratum to: Identification of specific calcitonin-like receptor residues important for calcitonin gene-related peptide high affinity binding. BMC Pharmacol 2006. [PMCID: PMC1698909 DOI: 10.1186/1471-2210-6-14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
This is a correction article. After publication of this work [1], we became aware of the fact that Robert C. Speth was not included as an author. Dr. Speth put a considerable amount of time and effort into developing and preparing the radiopeptide used to carry out the radioligand binding studies reported in this manuscript and therefore should have originally been included as an author. We apologize to Dr. Speth for any inconvenience that this oversight might have caused and thank him for his invaluable contribution to this project.
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Abstract
Thyrotropin-releasing hormone (TRH) is a tripeptide that is widely distributed in the brain including the hippocampus where TRH receptors are also expressed. TRH has anti-epileptic effects and regulates arousal, sleep, cognition, locomotion and mood. However, the cellular mechanisms underlying such effects remain to be determined. We examined the effects of TRH on GABAergic transmission in the hippocampus and found that TRH increased the frequency of GABAA receptor-mediated spontaneous IPSCs in each region of the hippocampus but had no effects on miniature IPSCs or evoked IPSCs. TRH increased the action potential firing frequency recorded from GABAergic interneurons in CA1 stratum radiatum and induced membrane depolarization suggesting that TRH increases the excitability of interneurons to facilitate GABA release. TRH-induced inward current had a reversal potential close to the K+ reversal potential suggesting that TRH inhibits resting K+ channels. The involved K+ channels were sensitive to Ba2+ but resistant to other classical K+ channel blockers, suggesting that TRH inhibits the two-pore domain K+ channels. Because the effects of TRH were mediated via Galphaq/11, but were independent of its known downstream effectors, a direct coupling may exist between Galphaq/11 and K+ channels. Inhibition of the function of dynamin slowed the desensitization of TRH responses. TRH inhibited seizure activity induced by Mg2+ deprivation, but not that generated by picrotoxin, suggesting that TRH-mediated increase in GABA release contributes to its anti-epileptic effects. Our results demonstrate a novel mechanism to explain some of the hippocampal actions of TRH.
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Affiliation(s)
- Pan-Yue Deng
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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Banerjee S, Evanson J, Harris E, Lowe SL, Thomasson KA, Porter JE. Identification of specific calcitonin-like receptor residues important for calcitonin gene-related peptide high affinity binding. BMC Pharmacol 2006; 6:9. [PMID: 16776831 PMCID: PMC1525162 DOI: 10.1186/1471-2210-6-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2005] [Accepted: 06/15/2006] [Indexed: 11/29/2022] Open
Abstract
Background Calcitonin gene-related peptide (CGRP) is a vasoactive neuropeptide whose biological activity has potential therapeutic value for many vascular related diseases. CGRP is a 37 amino acid neuropeptide that signals through a G protein-coupled receptor belonging to the secretin receptor family. Previous studies on the calcitonin-like receptor (CLR), which requires co-expression of the receptor-activity-modifying protein-1 (RAMP1) to function as a CGRP receptor, have shown an 18 amino acid N-terminus sequence important for binding CGRP. Moreover, several investigations have recognized the C-terminal amidated phenylalanine (F37) of CGRP as essential for docking to the mature receptor. Therefore, we hypothesize that hydrophobic amino acids within the previously characterized 18 amino acid CLR N-terminus domain are important binding contacts for the C-terminal phenylalaninamide of CGRP. Results Two leucine residues within this previously characterized CLR N-terminus domain, when mutated to alanine and expressed on HEK293T cells stably transfected with RAMP1, demonstrated a significantly decreased binding affinity for CGRP compared to wild type receptor. Additional decreases in binding affinity for CGRP were not found when both leucine mutations were expressed in the same CLR construct. Decreased binding characteristic of these leucine mutant receptors was observed for all CGRP ligands tested that contained the necessary amidated phenylalanine at their C-terminus. However, there was no difference in the potency of CGRP to increase cAMP production by these leucine mutant receptors when compared to wild type CLR, consistent with the notion that the neuropeptide C-terminal F37 is important for docking but not activation of the receptor. This observation was conserved when modified CGRP ligands lacking the amidated F37 demonstrated similar potencies to generate cAMP at both wild type and mutant CLRs. Furthermore, these modified CGRP ligands displayed a significant but similar loss of binding for all leucine mutant and wild type CLR because the important receptor contact on the neuropeptide was missing in all experimental situations. Conclusion These results are consistent with previous structure-function investigations of the neuropeptide and are the first to propose specific CLR binding contacts for the amidated F37 of CGRP that are important for docking but not activation of the mature CGRP receptor.
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Affiliation(s)
- Sugato Banerjee
- Department of Pharmacology, Physiology & Therapeutics, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037, USA
| | - Janel Evanson
- Department of Pharmacology, Physiology & Therapeutics, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037, USA
| | - Erik Harris
- Department of Pharmacology, Physiology & Therapeutics, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037, USA
| | - Stephen L Lowe
- Department of Chemistry, University of North Dakota, Grand Forks, ND 58202-9024, USA
| | - Kathryn A Thomasson
- Department of Chemistry, University of North Dakota, Grand Forks, ND 58202-9024, USA
| | - James E Porter
- Department of Pharmacology, Physiology & Therapeutics, School of Medicine & Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037, USA
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Hillman KL, Doze VA, Porter JE. α adrenergic activation of GABAergic interneurons in region CA1 of the rat hippocampus. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a246-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kristin Louise Hillman
- PharmacologyPhysiology & TherapeuticsUniversity of North Dakota501 N. Columbia RoadGrand ForksND58202
| | - Van A Doze
- PharmacologyPhysiology & TherapeuticsUniversity of North Dakota501 N. Columbia RoadGrand ForksND58202
| | - James E Porter
- PharmacologyPhysiology & TherapeuticsUniversity of North Dakota501 N. Columbia RoadGrand ForksND58202
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Hillman KL, Knudson CA, Carr PA, Doze VA, Porter JE. Adrenergic receptor characterization of CA1 hippocampal neurons using real time single cell RT-PCR. ACTA ACUST UNITED AC 2005; 139:267-76. [PMID: 16005103 DOI: 10.1016/j.molbrainres.2005.05.033] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [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: 09/03/2004] [Revised: 05/14/2005] [Accepted: 05/24/2005] [Indexed: 11/17/2022]
Abstract
The CA1 region of the rat hippocampus exhibits both alpha and beta adrenergic receptor (AR) responses, however, the specific AR subtypes involved and the neuronal expression patterns for these receptors are not well understood. We have employed single cell real time RT-PCR in conjunction with cell-specific immunohistochemical markers to determine the AR expression patterns for hippocampal neurons located in CA1, a region often implicated in learning and memory processes. Cytoplasmic samples were taken from 55 individual cells located in stratum oriens, pyramidale, or radiatum and reverse transcribed. All successfully amplified pyramidal neuron samples (n = 17) expressed mRNA for the beta2AR, with four cells additionally expressing mRNA for the beta1AR subtype. Positive interneurons from stratum oriens (n = 10) and stratum radiatum (n = 8) expressed mRNA for the alpha1A and/or alpha(1B)AR (n = 9/18) only when coexpressing transcripts for somatostatin. Interneurons containing neuropeptide Y or cholecystokinin (n = 9/18) were not positive for any of the nine AR subtypes, suggesting that CA1 interneuron AR expression is limited to a subset of somatostatin-positive cells. These findings suggest that only a select number of AR subtypes are transcriptionally expressed in CA1 and that these receptors are selective to specific neuronal cell types.
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Affiliation(s)
- Kristin L Hillman
- Department of Pharmacology, Physiology, and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Road, Grand Forks, ND 58203, USA
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Harmon EB, Porter JM, Porter JE. Beta-adrenergic receptor activation in immortalized human urothelial cells stimulates inflammatory responses by PKA-independent mechanisms. Cell Commun Signal 2005; 3:10. [PMID: 16091148 PMCID: PMC1198236 DOI: 10.1186/1478-811x-3-10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Accepted: 08/09/2005] [Indexed: 11/10/2022] Open
Abstract
Background Interstitial cystitis (IC) is a debilitating disease characterized by chronic inflammation of the urinary bladder, yet specific cellular mechanisms of inflammation in IC are largely unknown. Multiple lines of evidence suggest that β-adrenergic receptor (AR) signaling is increased in the inflamed urothelium, however the precise effects of these urothelial cell signals have not been studied. In order to better elucidate the AR signaling mechanisms of inflammation associated with IC, we have examined the effects of β-AR stimulation in an immortalized human urothelial cell line (UROtsa). For these studies, UROtsa cells were treated with effective concentrations of the selective β-AR agonist isoproterenol, in the absence or presence of selective inhibitors of protein kinase A (PKA). Cell lysates were analyzed by radioimmunoassay for generation of cAMP or by Western blotting for induction of protein products associated with inflammatory responses. Results Radioligand binding demonstrated the presence of β-ARs on human urothelial UROtsa cell membranes. Stimulating UROtsa cells with isoproterenol led to concentration-dependent increases of cAMP production that could be inhibited by pretreatment with a blocking concentration of the selective β-AR antagonist propranolol. In addition, isoproterenol activation of these same cells led to significant increases in the amount of phosphorylated extracellular signal-regulated kinase (pERK), inducible nitric oxide synthase (iNOS) and the induced form of cyclooxygenase (COX-2) when compared to control. Moreover, preincubation of UROtsa cells with the selective PKA inhibitors H-89 or Rp-cAMPs did not diminish this isoproterenol mediated phosphorylation of ERK or production of iNOS and COX-2. Conclusion Functional β-ARs expressed on human urothelial UROtsa cell membranes increase the generation of cAMP and production of protein products associated with inflammation when activated by the selective β-AR agonist isoproterenol. However, the increased production of iNOS and COX-2 by isoproterenol is not blocked when UROtsa cells are preincubated with inhibitors of PKA. Therefore, UROtsa cell β-AR activation significantly increases the amount of iNOS and COX-2 produced by a PKA-independent mechanism. Consequently, this immortalized human urothelial cell line can be useful in characterizing potential AR signaling mechanisms associated with chronic inflammatory diseases of the bladder.
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Affiliation(s)
- Erin B Harmon
- Department of Pharmacology, Physiology, and Therapeutics; University of North Dakota; School of Medicine & Health Sciences; Grand Forks, ND 58202-9037, USA
| | - Jill M Porter
- Department of Pharmacology, Physiology, and Therapeutics; University of North Dakota; School of Medicine & Health Sciences; Grand Forks, ND 58202-9037, USA
| | - James E Porter
- Department of Pharmacology, Physiology, and Therapeutics; University of North Dakota; School of Medicine & Health Sciences; Grand Forks, ND 58202-9037, USA
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Jurgens CWD, Boese SJ, King JD, Pyle SJ, Porter JE, Doze VA. Adrenergic receptor modulation of hippocampal CA3 network activity. Epilepsy Res 2005; 66:117-28. [PMID: 16140503 DOI: 10.1016/j.eplepsyres.2005.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [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: 04/28/2005] [Revised: 07/14/2005] [Accepted: 07/27/2005] [Indexed: 10/25/2022]
Abstract
Norepinephrine (NE) has demonstrated proconvulsant and antiepileptic properties; however, the specific pharmacology of these actions has not been clearly established. To address this, we studied the effect of NE on hippocampal CA3 epileptiform activity. Frequency changes of burst discharges in response to NE were biphasic; low concentrations increased the number of bursts, while higher concentrations reduced their frequency, suggesting the involvement of multiple adrenergic receptor (AR) types. This hypothesis was confirmed when, in the presence of betaAR blockade, increasing concentrations of NE caused a monophasic decrease in epileptiform activity. Antagonists selective for alpha1 or alpha2ARs were then used to determine which alphaAR type was involved. While discriminating concentrations of the alpha1AR antagonists prazosin and terazosin had no effect, selective amounts of the alpha2AR antagonists RS79948 and RX821002 significantly reduced the potency of NE in decreasing epileptiform activity. Furthermore, this antiepileptic action of NE persisted when all GABA-mediated inhibition was blocked. This data suggests that, under conditions of impaired GABAergic inhibition, the excitatory and inhibitory effects of NE on hippocampal CA3 epileptiform activity are mediated primarily via beta and alpha2ARs, respectively. Moreover, our results imply that the antiepileptic effect of alpha2AR activation in CA3 is not dependent on the GABAergic system.
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Affiliation(s)
- Chris W D Jurgens
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 N. Columbia Road, Grand Forks, ND 58203, USA
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Jurgens CWD, Rau KE, Knudson CA, King JD, Carr PA, Porter JE, Doze VA. Beta1 adrenergic receptor-mediated enhancement of hippocampal CA3 network activity. J Pharmacol Exp Ther 2005; 314:552-60. [PMID: 15908512 DOI: 10.1124/jpet.105.085332] [Citation(s) in RCA: 31] [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] [Indexed: 11/22/2022] Open
Abstract
Norepinephrine is an endogenous neurotransmitter distributed throughout the mammalian brain. In higher cortical structures such as the hippocampus, norepinephrine, via beta adrenergic receptor (AR) activation, has been shown to reinforce the cognitive processes of attention and memory. In this study, we investigated the effect of beta1AR activation on hippocampal cornu ammonis 3 (CA3) network activity. AR expression was first determined using immunocytochemistry with antibodies against beta1ARs, which were found to be exceptionally dense in hippocampal CA3 pyramidal neurons. CA3 network activity was then examined in vitro using field potential recordings in rat brain slices. The selective betaAR agonist isoproterenol caused an enhancement of hippocampal CA3 network activity, as measured by an increase in frequency of spontaneous burst discharges recorded in the CA3 region. In the presence of alphaAR blockade, concentration-response curves for isoproterenol, norepinephrine, and epinephrine suggested that a beta1AR was involved in this response, and the rank order of potency was isoproterenol > norepinephrine = epinephrine. Finally, equilibrium dissociation constants (pK(b)) of subtype-selective betaAR antagonists were functionally determined to characterize the AR subtype modulating hippocampal CA3 activity. The selective beta1AR antagonists atenolol and metoprolol blocked isoproterenol-induced enhancement, with apparent K(b) values of 85 +/- 36 and 3.9 +/- 1.7 nM, respectively. In contrast, the selective beta2AR antagonists ICI-118,551 and butoxamine inhibited isoproterenol-mediated enhancement with apparent low affinities (K(b) of 222 +/- 61 and 9268 +/- 512 nM, respectively). Together, this pharmacological profile of subtype-selective betaAR antagonists indicates that in this model, beta1AR activation is responsible for the enhanced hippocampal CA3 network activity initiated by isoproterenol.
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Affiliation(s)
- Chris W D Jurgens
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Rd., Grand Forks, ND 58202-9037, USA
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Hillman KL, Doze VA, Porter JE. Functional characterization of the beta-adrenergic receptor subtypes expressed by CA1 pyramidal cells in the rat hippocampus. J Pharmacol Exp Ther 2005; 314:561-7. [PMID: 15908513 DOI: 10.1124/jpet.105.084947] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [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] [Indexed: 11/22/2022] Open
Abstract
Recent studies have demonstrated that activation of the beta-adrenergic receptor (AR) using the selective beta-AR agonist isoproterenol (ISO) facilitates pyramidal cell long-term potentiation in the cornu ammonis 1 (CA1) region of the rat hippocampus. We have previously analyzed beta-AR genomic expression patterns of 17 CA1 pyramidal cells using single cell reverse transcription-polymerase chain reaction, demonstrating that all samples expressed the beta2-AR transcript, with four of the 17 cells additionally expressing mRNA for the beta1-AR subtype. However, it has not been determined which beta-AR subtypes are functionally expressed in CA1 for these same pyramidal neurons. Using cell-attached recordings, we tested the ability of ISO to increase pyramidal cell action potential (AP) frequency in the presence of subtype-selective beta-AR antagonists. ICI-118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol] and butoxamine [alpha-[1-(t-butylamino)ethyl]-2,5-dimethoxybenzyl alcohol) hydrochloride], agents that selectively block the beta2-AR, produced significant parallel rightward shifts in the concentration-response curves for ISO. From these curves, apparent equilibrium dissociation constant (K(b)) values of 0.3 nM for ICI-118,551 and 355 nM for butoxamine were calculated using Schild regression analysis. Conversely, effective concentrations of the selective beta1-AR antagonists CGP 20712A [(+/-)-2-hydroxy-5-[2-([2-hydroxy-3-(4-[1-methyl-4-(trifluoromethyl)-1H-imidazol-2-yl]phenoxy)propyl]amino)ethoxy]-benzamide methanesulfonate] and atenolol [4-[2'-hydroxy-3'-(isopropyl-amino)propoxy]phenylacetamide] did not significantly affect the pyramidal cell response to ISO. However, at higher concentrations, atenolol significantly decreased the potency for ISO-mediated AP frequencies. From these curves, an apparent atenolol K(b) value of 3162 nM was calculated. This pharmacological profile for subtype-selective beta-AR antagonists indicates that beta2-AR activation is mediating the increased AP frequency. Knowledge of functional AR expression in CA1 pyramidal neurons will aid future long-term potentiation studies by allowing selective manipulation of specific beta-AR subtypes.
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MESH Headings
- Action Potentials/drug effects
- Adrenergic beta-Agonists/pharmacology
- Adrenergic beta-Antagonists/pharmacology
- Animals
- Electrophysiology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Hippocampus/cytology
- Hippocampus/drug effects
- Isoproterenol/pharmacology
- Male
- Pyramidal Cells/drug effects
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, beta/biosynthesis
- Receptors, Adrenergic, beta/classification
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta-2/drug effects
- Receptors, Adrenergic, beta-2/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Kristin L Hillman
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Rd., Grand Forks, ND 58202-9037, USA
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45
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Murphy TC, Poppe C, Porter JE, Montine TJ, Picklo MJ. 4‐Hydroxy‐trans‐2‐nonenoic acid is a γ‐hydroxybutyrate receptor ligand in the cerebral cortex and hippocampus. J Neurochem 2004; 89:1462-70. [PMID: 15189349 DOI: 10.1111/j.1471-4159.2004.02442.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [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] [Indexed: 11/30/2022]
Abstract
Elevated production of 4-hydroxy-trans-2-nonenal (HNE) occurs in numerous neurological disorders involving oxidative damage. HNE is metabolized to the non-toxic 4-hydroxy-trans-2-nonenoic acid (HNEAcid) by aldehyde dehydrogenases in the rat cerebral cortex. Based upon the structural similarity of HNEAcid to ligands of the gamma-hydroxybutyrate (GHB) receptor, we hypothesized that HNEAcid is an endogenous ligand for the GHB receptor. HNEAcid displaced the specific binding of the GHB receptor ligand (3)H-NCS382 (30 nm) in membrane preparations of human frontal cerebral cortex and whole rat cerebral cortex with IC(50s) of 3.9 +/- 1.1 and 5.6 +/- 1.2 micro m, respectively. Inhibition was attenuated when the carboxyl group of HNEAcid was replaced with an aldehyde or an alcohol. HNEAcid (300 micro m) did not displace the binding of beta-adrenergic receptor and GABA(B) receptor antagonists, demonstrating the selectivity of HNEAcid for the GHB receptor. HNEAcid is formed in homogenates of human frontal cortical gray matter in an NAD(+)-dependent (V(Max), 0.71 nmol/min/mg) and NADP(+)-dependent (V(Max), 0.12 nmol/min/mg) manner. Lastly, (3)H-NCS382 binding is elevated 2.7-fold with age in the cerebral cortex of rats. Our data demonstrate that an HNE metabolite, formed in rat and human brain, is a signaling molecule analogous to other bioactive lipid peroxidation products.
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Affiliation(s)
- Tonya C Murphy
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58203, USA
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Ren J, Porter JE, Wold LE, Aberle NS, Muralikrishnan D, Haselton JR. Depressed contractile function and adrenergic responsiveness of cardiac myocytes in an experimental model of Parkinson disease, the MPTP-treated mouse. Neurobiol Aging 2004; 25:131-8. [PMID: 14675739 DOI: 10.1016/s0197-4580(03)00035-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [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] [Indexed: 11/22/2022]
Abstract
Radiotracer and biochemical studies have shown that patients with Parkinson disease lack functional sympathetic innervation to the heart. The same observation was made in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), an experimental model of Parkinson disease. This study examined the mechanical properties, adrenergic receptor level and intracellular Ca2+ handling in cardiac myocytes isolated from C57/BL6 mice that received either MPTP (30 mg/kg, i.p., twice in 24 h) or vehicle. Mechanical properties were evaluated using an IonOptix MyoCam system. Myocytes were electrically stimulated at 0.5 Hz. The contractile properties analyzed included peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90), and maximal velocities of shortening and relengthen (+/-dL/dt). Intracellular Ca2+ handling was evaluated with fura 2. Myocytes from MPTP-treated mice exhibited a depressed PS (85% of normal), normal TPS, prolonged TR90 (147% of normal), and reduced +/-dL/dt (both 79% of normal). These results were correlated with a 67% reduction of beta-adrenergic receptor expression in myocardial membranes from MPTP-treated mice when compared to normal. Myocytes from MPTP-treated mice also exhibited a reduced peak of intracellular Ca2+ sequestration and sarcoplasmic reticulum (SR) Ca2+ load (55 and 38% of normal, respectively). The resting intracellular Ca2+ and Ca2+-transient decay were comparable to the values seen in myocytes from untreated mice. Myocytes from MPTP-treated and untreated mice were equally responsive over a range of stimulation frequencies (0.1, 0.5, 1, 3 and 5 z). Response to norepinephrine (1 microM) and isoproterenol (1 microM) was reduced in myocytes from MPTP-treated mice. These results demonstrate substantial cardiac dysfunctions in this model of experimental Parkinson disease, probably due to reduced adrenergic responsiveness and SR Ca2+ load.
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Affiliation(s)
- Jun Ren
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
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Bailon P, Palleroni A, Schaffer CA, Spence CL, Fung WJ, Porter JE, Ehrlich GK, Pan W, Xu ZX, Modi MW, Farid A, Berthold W, Graves M. Rational design of a potent, long-lasting form of interferon: a 40 kDa branched polyethylene glycol-conjugated interferon alpha-2a for the treatment of hepatitis C. Bioconjug Chem 2001; 12:195-202. [PMID: 11312680 DOI: 10.1021/bc000082g] [Citation(s) in RCA: 433] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A potent, long-lasting form of interferon alpha-2a mono-pegylated with a 40 kilodalton branched poly(ethylene glycol) was designed, synthesized, and characterized. Mono-pegylated interferon alpha-2a was comprised of four major positional isomers involving Lys31, Lys121, Lys131, and Lys134 of interferon. The in vitro anti-viral activity of pegylated interferon alpha-2a was found to be only 7% of the original activity. In contrast, the in vivo antitumor activity was severalfold enhanced compared to interferon alpha-2a. Pegylated interferon alpha-2a showed no immunogenicity in mice. After subcutaneous injection of pegylated interferon alpha-2a, a 70-fold increase in serum half-life and a 50-fold increase in mean plasma residence time concomitant with sustained serum concentrations were observed relative to interferon alpha-2a. These preclinical results suggest a significantly enhanced human pharmacological profile for pegylated interferon alpha-2a. Results of Phase II/III hepatitis C clinical trials in humans confirmed the superior efficacy of pegylated interferon alpha-2a compared to unmodified interferon alpha-2a.
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Affiliation(s)
- P Bailon
- Hoffmann-La Roche Inc, Nutley, New Jersey 07110, USA.
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Abstract
In this work, a previously proposed methodology for the optimization of analytical scale protein separations using ion-exchange chromatography is subjected to two challenging case studies. The optimization methodology uses a Doehlert shell design for design of experiments and a novel criteria function to rank chromatograms in order of desirability. This chromatographic optimization function (COF) accounts for the separation between neighboring peaks, the total number of peaks eluted, and total analysis time. The COF is penalized when undesirable peak geometries (i.e., skewed and/or shouldered peaks) are present as determined by a vector quantizing neural network. Results of the COF analysis are fit to a quadratic response model, which is optimized with respect to the optimization variables using an advanced Nelder and Mead simplex algorithm. The optimization methodology is tested on two case study sample mixtures, the first of which is composed of equal parts of lysozyme, conalbumin, bovine serum albumin, and transferrin, and the second of which contains equal parts of conalbumin, bovine serum albumin, tranferrin, beta-lactoglobulin, insulin, and alpha -chymotrypsinogen A. Mobile-phase pH and gradient length are optimized to achieve baseline resolution of all solutes for both case studies in acceptably short analysis times, thus demonstrating the usefulness of the empirical optimization methodology.
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Affiliation(s)
- E J Klein
- Stevens Institute of Technology, Department of Chemical Engineering, Hoboken, New Jersey 07030, USA.
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Porter JE, Perez DM. Influence of a lysine 331 counterion on the pK(a) of aspartic acid 125: evidence for a salt-bridge interaction and role in alpha(1b)-adrenergic receptor activation. J Pharmacol Exp Ther 2000; 292:440-8. [PMID: 10604981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
We have hypothesized previously that a salt-bridge constraint exists in the alpha(1b)-adrenergic receptor (AR). Docking of the agonist epinephrine can disrupt this constraint via competition of its protonated amine, leading to an agonist-induced activation of second messengers. The amino acids, K331 and D125, which comprise this salt-bridge, should be closely associated with each other in the unbound form of the alpha(1b)-AR. This ionic association should stabilize the negative charge of D125, leading to an increase in its acid strength or a decreased pK(a). If the charged state of D125 is important for agonist binding, then changing the type of amino acid at position 331 should decrease the acid strength of D125, leading to epinephrine affinity changes for the alpha(1b)-AR. To test this hypothesis, site-directed mutagenesis was performed at position 331 of the alpha(1b)-AR. The effect these substitutions had on D125 acid strength was quantitated via epinephrine affinity changes calculated from competition binding experiments performed at different pH values. For all mutations of the alpha(1b)-AR where the positive charge at position 331 was eliminated, there was a significant increase in the pK(a) ( congruent with 0.73) of an acidic amino acid(s). In addition, there was an increase in the binding affinity of epinephrine for these mutants that was associated with a gain in the basal production of inositol triphosphates. These results are consistent with an aspartic acid residue as the counterion for K331 of the salt-bridge constraint, which disrupted, is a part of the receptor activation process. Moreover, changes in the pK(a) of D125 were not dependent on the type of amino acid substituted at position 331. This suggests a mechanism in which K331 is no longer influencing D125 after salt-bridge disruption in the wild-type alpha(1b)-AR, but may move to another stabilized position, analogous to what has been suggested for bacteriorhodopsin. Differences from the wild-type receptor in D125 pK(a) for the K331 mutations were used to estimate the free-energy potential of the constraining salt-bridge. This free energy ( congruent with 1 kcal/mol) is significant, but weak enough to be consistent with an activational mechanism where docking of the receptor agonist has sufficient free energy to cause disruption of the salt-bridge.
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Affiliation(s)
- J E Porter
- Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Porter JE, Perez DM. Characteristics for a salt-bridge switch mutation of the alpha(1b) adrenergic receptor. Altered pharmacology and rescue of constitutive activity. J Biol Chem 1999; 274:34535-8. [PMID: 10574914 DOI: 10.1074/jbc.274.49.34535] [Citation(s) in RCA: 39] [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] [Indexed: 11/06/2022] Open
Abstract
Agonist-dependent activation of the alpha(1)-adrenergic receptor is postulated to be initiated by disruption of an interhelical salt-bridge constraint between an aspartic acid (Asp-125) and a lysine residue (Lys-331) in transmembrane domains three and seven, respectively. Single point mutations that disrupt the charges of either of these residues results in constitutive activity. To validate this hypothesis, we used site-directed mutagenesis to switch the position of these amino acids to observe, if possible, regeneration of the salt-bridge reverses that the constitutive activity of the single point mutations. The transiently expressed switch mutant receptor displayed an altered pharmacological profile. The affinity of selective alpha(1b)-adrenergic receptor antagonists for the switch mutant (D125K/K331D) was no different from the wild-type alpha(1b)-adrenergic receptor, suggesting that both receptors are maintaining similar tertiary structures in the cell membrane. However, there was a significant 4-6-fold decrease in the affinity of protonated amine receptor agonists and a 3-6-fold increase in the affinity of carboxylated catechol derivatives for the switch mutant compared with the wild-type alpha(1b)-adrenergic receptor. This pharmacology is consistent with a reversed charge at position 125 in transmembrane domain three. Interestingly, the ability of either a negatively or positively charged agonist to generate soluble inositol phosphates was similar for both types of receptors. Finally, the switch mutant (D125K/K331D) displayed similar basal signaling activity as the wild-type receptor, reversing the constitutive activity of the single point mutations (D125K and K331D). This suggests an ionic constraint has been reformed in the switch mutant analogous to the restraint previously described for the wild-type alpha(1b)-adrenergic receptor. These results strongly establish the disruption of an electrostatic interaction as an initial step in the agonist-dependent activation of alpha(1)-adrenergic receptors.
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Affiliation(s)
- J E Porter
- Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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