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Wang B, Chen J, Wang S, Chen L, Zhang X, Zhou T, Zhong J, Zhang C, He Y, Zuo Y, Feng H, Yin Y, Ge H. Kv1.3 Blockade Alleviates White Matter Injury through Reshaping M1/M2 Phenotypes via the NF-κB Signaling Pathway after Intracerebral Hemorrhage. J Integr Neurosci 2023; 22:171. [PMID: 38176920 DOI: 10.31083/j.jin2206171] [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] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND White matter injury (WMI) in basal ganglia usually induces long-term disability post intracerebral hemorrhage (ICH). Kv1.3 is an ion channel expressed in microglia and induces neuroinflammation after ICH. Here, we investigated the functions and roles of Kv1.3 activation-induced inflammatory response in WMI and the Kv1.3 blockade effect on microglia polarization after ICH. METHODS Mice ICH model was constructed by autologous blood injection. The expression of Kv1.3 was measured using immunoblot, real-time quantitative polymerase chain reaction (RT-qPCR), and immunostaining assays. Then, the effect of administration of 5-(4-Phenoxybutoxy) psoralen (PAP-1), a selectively pharmacological Kv1.3 blocker, was investigated using open field test (OFT) and basso mouse score (BMS). RT-qPCR, immunoblot, and enzyme-linked immunosorbent assay (ELISA) were taken to elucidate the expression of pro-inflammatory or anti-inflammatory factors around hematoma. PAP-1's function in regulating microglia polarization was investigated using immunoblot, RT-qPCR, and immunostaining assays. The downstream PAP-1 signaling pathway was determined by RT-qPCR and immunoblot. RESULTS Kv1.3 expression was increased in microglia around the hematoma significantly after ICH. PAP-1 markedly improved neurological outcomes and the WMI by reducing pro-inflammatory cytokine accumulation and upregulating anti-inflammatory factors. Mechanistically, PAP-1 reduces NF-κB p65 and p50 activation, thus facilitating microglia polarization into M2-like microglia, which exerts this beneficial effect. CONCLUSIONS PAP-1 reduced pro-inflammatory cytokines accumulation and increased anti-inflammatory factors by facilitating M2-like microglia polarization via the NF-κB signaling pathway. Thus, the current study shows that the Kv1.3 blockade is capable of ameliorating WMI by facilitating M2-like phenotype microglia polarization after ICH.
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Affiliation(s)
- Bo Wang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Jie Chen
- Department of Neurology, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Shuhong Wang
- Department of Emergency, Affiliated Hospital of Zunyi Medical University, 563000 Zunyi, Guizhou, China
| | - Lin Chen
- Department of Emergency, Affiliated Hospital of Zunyi Medical University, 563000 Zunyi, Guizhou, China
| | - Xuyang Zhang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Tengyuan Zhou
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Jun Zhong
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Chao Zhang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Yijia He
- Department of Fundamental Medicine, Chengdu University of Traditional Chinese Medicine, 611137 Chengdu, Sichuan, China
| | - Yonglin Zuo
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Hua Feng
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Yi Yin
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Hongfei Ge
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), 400038 Chongqing, China
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Karra DA, Chadwick CC, Stavroulaki EM, Pitropaki MN, Flouraki E, Allenspach K, Lidbury JA, Steiner JM, Xenoulis PG. Fecal acute phase proteins in cats with chronic enteropathies. J Vet Intern Med 2023; 37:1750-1759. [PMID: 37401847 PMCID: PMC10473003 DOI: 10.1111/jvim.16802] [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: 12/05/2022] [Accepted: 06/21/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Chronic enteropathies (CE) are common in cats and reliable biomarkers that can distinguish different causes and predict or monitor response to treatment are currently lacking. HYPOTHESIS To evaluate certain acute phase proteins in feces that could potentially be used as biomarkers in cats with CE. ANIMALS Twenty-eight cats with either inflammatory bowel disease (IBD; n = 13), food-responsive enteropathy (FRE; n = 3) or small cell gastrointestinal lymphoma (SCGL; n = 12) and 29 healthy control cats were prospectively enrolled. METHODS Fecal concentrations of haptoglobin, alpha-1-acid-glycoprotein (AGP), pancreatitis-associated protein-1 (PAP-1), ceruloplasmin, and C-reactive protein (CRP) were measured using Spatial Proximity Analyte Reagent Capture Luminescence (SPARCL) immunoassays before and after initiation of treatment. Cats were treated with diet and/or prednisolone (IBD cats), plus chlorambucil (SCGL cats). RESULTS Compared with controls, median fecal AGP concentrations were significantly lower (25.1 vs 1.8 μg/g; P = .003) and median fecal haptoglobin (0.17 vs 0.5 μg/g), PAP-1 (0.04 vs 0.4 μg/g) and ceruloplasmin (0.15 vs 4.2 μg/g) concentrations were significantly higher (P < .001) in cats with CE. Median fecal AGP concentrations were significantly lower (P = .01) in cats with IBD and FRE (0.6 μg/g) compared with cats with SCGL (10.75 μg/g). A significant reduction was found in CE cats after treatment for median fecal ceruloplasmin concentrations (6.36 vs 1.16 μg/g; P = .04). CONCLUSIONS Fecal AGP concentration shows promise to differentiate cats with SCGL from cats with IBD and FRE. Fecal ceruloplasmin concentrations may be useful to objectively monitor response to treatment in cats with CE.
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Affiliation(s)
| | | | | | | | | | - Karin Allenspach
- Iowa State UniversityCollege of Veterinary Medicine, Veterinary Clinical SciencesAmesIowaUSA
| | - Jonathan A. Lidbury
- Texas A&M University – Gastrointestinal LaboratoryCollege of Veterinary Medicine & Biomedical SciencesCollege StationTexasUSA
| | - Joerg M. Steiner
- Texas A&M UniversityGastrointestinal LaboratoryCollege StationTexasUSA
| | - Panagiotis G. Xenoulis
- University of ThessalySmall Animal ClinicKarditsaGreece
- Texas A&M UniversityGastrointestinal LaboratoryCollege StationTexasUSA
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Lee RD, Chen YJ, Singh L, Nguyen HM, Wulff H. Immunocytoprotection after reperfusion with Kv1.3 inhibitors has an extended treatment window for ischemic stroke. Front Pharmacol 2023; 14:1190476. [PMID: 37180699 PMCID: PMC10166874 DOI: 10.3389/fphar.2023.1190476] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/17/2023] [Indexed: 05/16/2023] Open
Abstract
Introduction: Mechanical thrombectomy has improved treatment options and outcomes for acute ischemic stroke with large artery occlusion. However, as the time window of endovascular thrombectomy is extended there is an increasing need to develop immunocytoprotective therapies that can reduce inflammation in the penumbra and prevent reperfusion injury. We previously demonstrated, that by reducing neuroinflammation, KV1.3 inhibitors can improve outcomes not only in young male rodents but also in female and aged animals. To further explore the therapeutic potential of KV1.3 inhibitors for stroke therapy, we here directly compared a peptidic and a small molecule KV1.3 blocker and asked whether KV1.3 inhibition would still be beneficial when started at 72 hours after reperfusion. Methods: Transient middle cerebral artery occlusion (tMCAO, 90-min) was induced in male Wistar rats and neurological deficit assessed daily. On day-8 infarction was determined by T2-weighted MRI and inflammatory marker expression in the brain by quantitative PCR. Potential interactions with tissue plasminogen activator (tPA) were evaluated in-vitro with a chromogenic assay. Results: In a direct comparison with administration started at 2 hours after reperfusion, the small molecule PAP-1 significantly improved outcomes on day-8, while the peptide ShK-223 failed to reduce infarction and neurological deficits despite reducing inflammatory marker expression. PAP-1 still provided benefits when started 72 hours after reperfusion. PAP-1 does not reduce the proteolytic activity of tPA. Discussion: Our studies suggest that KV1.3 inhibition for immunocytoprotection after ischemic stroke has a wide therapeutic window for salvaging the inflammatory penumbra and requires brain-penetrant small molecules.
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Affiliation(s)
- Ruth D. Lee
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Yi-Je Chen
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
- Animal Models Core, Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Latika Singh
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Hai M. Nguyen
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
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Nguyen HM, di Lucente J, Chen YJ, Cui Y, Ibrahim RH, Pennington MW, Jin LW, Maezawa I, Wulff H. Biophysical basis for Kv1.3 regulation of membrane potential changes induced by P2X4-mediated calcium entry in microglia. Glia 2020; 68:2377-2394. [PMID: 32525239 PMCID: PMC7540709 DOI: 10.1002/glia.23847] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 04/17/2020] [Accepted: 05/07/2020] [Indexed: 12/02/2022]
Abstract
Microglia‐mediated inflammation exerts adverse effects in ischemic stroke and in neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the voltage‐gated potassium channel Kv1.3 is required for microglia activation. Both genetic deletion and pharmacological inhibition of Kv1.3 are effective in reducing microglia activation and the associated inflammatory responses, as well as in improving neurological outcomes in animal models of AD and ischemic stroke. Here we sought to elucidate the molecular mechanisms underlying the therapeutic effects of Kv1.3 inhibition, which remain incompletely understood. Using a combination of whole‐cell voltage‐clamp electrophysiology and quantitative PCR (qPCR), we first characterized a stimulus‐dependent differential expression pattern for Kv1.3 and P2X4, a major ATP‐gated cationic channel, both in vitro and in vivo. We then demonstrated by whole‐cell current‐clamp experiments that Kv1.3 channels contribute not only to setting the resting membrane potential but also play an important role in counteracting excessive membrane potential changes evoked by depolarizing current injections. Similarly, the presence of Kv1.3 channels renders microglia more resistant to depolarization produced by ATP‐mediated P2X4 receptor activation. Inhibiting Kv1.3 channels with ShK‐223 completely nullified the ability of Kv1.3 to normalize membrane potential changes, resulting in excessive depolarization and reduced calcium transients through P2X4 receptors. Our report thus links Kv1.3 function to P2X4 receptor‐mediated signaling as one of the underlying mechanisms by which Kv1.3 blockade reduces microglia‐mediated inflammation. While we could confirm previously reported differences between males and females in microglial P2X4 expression, microglial Kv1.3 expression exhibited no gender differences in vitro or in vivo. Main Points The voltage‐gated K+ channel Kv1.3 regulates microglial membrane potential. Inhibition of Kv1.3 depolarizes microglia and reduces calcium entry mediated by P2X4 receptors by dissipating the electrochemical driving force for calcium.
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Affiliation(s)
- Hai M Nguyen
- Department of Pharmacology, University of California, Davis, California, USA
| | - Jacopo di Lucente
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Yi-Je Chen
- Department of Pharmacology, University of California, Davis, California, USA
| | - Yanjun Cui
- Department of Pharmacology, University of California, Davis, California, USA
| | - Rania H Ibrahim
- Department of Pharmacology, University of California, Davis, California, USA
| | | | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California, USA
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Di Lucente J, Nguyen HM, Wulff H, Jin LW, Maezawa I. The voltage-gated potassium channel Kv1.3 is required for microglial pro-inflammatory activation in vivo. Glia 2018; 66:1881-1895. [PMID: 30043400 DOI: 10.1002/glia.23457] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 04/26/2018] [Accepted: 05/02/2018] [Indexed: 11/09/2022]
Abstract
Microglia show a rich repertoire of activation patterns regulated by a complex ensemble of surface ion channels, receptors, and transporters. We and others have investigated whether microglia vary their K+ channel expression as a means to achieve functional diversity. However, most of the prior studies were conducted using in vitro models such as BV2 cells, primary microglia, or brain slices in culture, which may not accurately reflect microglia physiology in adult individuals. Here we employed an in vivo mouse model of selective innate immune activation by intracerebroventricular injection of lipopolysaccharides (ICV-LPS) to determine the role of the voltage-gated Kv1.3 channel in LPS-induced M1-like microglial activation. Using microglia acutely isolated from adult brains, we detected Kv1.3 and Kir2.1 currents, and found that ICV-LPS increased the current density and RNA expression of Kv1.3 but did not affect those of Kir2.1. Genetic knockout of Kv1.3 abolished LPS-induced microglial activation exemplified by Iba-1 immunoreactivity and expression of pro-inflammatory mediators such as IL-1β, TNF-α, IL-6, and iNOS. Moreover, Kv1.3 knockout mitigated the LPS-induced impairment of hippocampal long-term potentiation (hLTP), suggesting that Kv1.3 activity regulates pro-inflammatory microglial neurotoxicity. Pharmacological intervention using PAP-1, a small molecule that selectively blocks homotetrameric Kv1.3 channels, achieved anti-inflammatory and hLTP-recovery effects similar to Kv1.3 knockout. We conclude that Kv1.3 is required for microglial M1-like pro-inflammatory activation in vivo. A significant implication of our in vivo data is that Kv1.3 blockers could be therapeutic candidates for neurological diseases where microglia-mediated neurotoxicity is implicated in the pathogenesis.
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Affiliation(s)
- Jacopo Di Lucente
- From the Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California
| | - Hai M Nguyen
- Department of Pharmacology, University of California, Davis, California
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California
| | - Lee-Way Jin
- From the Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California
| | - Izumi Maezawa
- From the Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California
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Nguyen HM, Grössinger EM, Horiuchi M, Davis KW, Jin LW, Maezawa I, Wulff H. Differential Kv1.3, KCa3.1, and Kir2.1 expression in "classically" and "alternatively" activated microglia. Glia 2016; 65:106-121. [PMID: 27696527 PMCID: PMC5113690 DOI: 10.1002/glia.23078] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [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: 03/10/2016] [Accepted: 09/15/2016] [Indexed: 11/10/2022]
Abstract
Microglia are highly plastic cells that can assume different phenotypes in response to microenvironmental signals. Lipopolysaccharide (LPS) and interferon-γ (IFN-γ) promote differentiation into classically activated M1-like microglia, which produce high levels of pro-inflammatory cytokines and nitric oxide and are thought to contribute to neurological damage in ischemic stroke and Alzheimer's disease. IL-4 in contrast induces a phenotype associated with anti-inflammatory effects and tissue repair. We here investigated whether these microglia subsets vary in their K+ channel expression by differentiating neonatal mouse microglia into M(LPS) and M(IL-4) microglia and studying their K+ channel expression by whole-cell patch-clamp, quantitative PCR and immunohistochemistry. We identified three major types of K+ channels based on their biophysical and pharmacological fingerprints: a use-dependent, outwardly rectifying current sensitive to the KV 1.3 blockers PAP-1 and ShK-186, an inwardly rectifying Ba2+ -sensitive Kir 2.1 current, and a Ca2+ -activated, TRAM-34-sensitive KCa 3.1 current. Both KV 1.3 and KCa 3.1 blockers inhibited pro-inflammatory cytokine production and iNOS and COX2 expression demonstrating that KV 1.3 and KCa 3.1 play important roles in microglia activation. Following differentiation with LPS or a combination of LPS and IFN-γ microglia exhibited high KV 1.3 current densities (∼50 pA/pF at 40 mV) and virtually no KCa 3.1 and Kir currents, while microglia differentiated with IL-4 exhibited large Kir 2.1 currents (∼ 10 pA/pF at -120 mV). KCa 3.1 currents were generally low but moderately increased following stimulation with IFN-γ or ATP (∼10 pS/pF). This differential K+ channel expression pattern suggests that KV 1.3 and KCa 3.1 inhibitors could be used to inhibit detrimental neuroinflammatory microglia functions. GLIA 2016;65:106-121.
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Affiliation(s)
- Hai M Nguyen
- Department of Pharmacology, University of California, Davis, California
| | - Eva M Grössinger
- Department of Pharmacology, University of California, Davis, California
| | - Makoto Horiuchi
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California.,M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, California
| | - Kyle W Davis
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California.,M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, California
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California.,M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, California
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California
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Ngala RA, Zaibi MS, Langlands K, Stocker CJ, Arch JRS, Cawthorne MA. Stimulation of glucose uptake in murine soleus muscle and adipocytes by 5-(4-phenoxybutoxy)psoralen ( PAP-1) may be mediated by Kv1.5 rather than Kv1.3. PeerJ 2014. [PMID: 25320682 DOI: 10.7717/peerj.614.] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kv1 channels are shaker-related potassium channels that influence insulin sensitivity. Kv1.3(-/-) mice are protected from diet-induced insulin resistance and some studies suggest that Kv1.3 inhibitors provide similar protection. However, it is unclear whether blockade of Kv1.3 in adipocytes or skeletal muscle increases glucose uptake. There is no evidence that the related channel Kv1.5 has any influence on insulin sensitivity and its expression in adipose tissue has not been reported. PAP-1 is a selective inhibitor of Kv1.3, with 23-fold, 32-fold and 125-fold lower potencies as an inhibitor of Kv1.5, Kv1.1 and Kv1.2 respectively. Soleus muscles from wild-type and genetically obese ob/ob mice were incubated with 2-deoxy[1-(14)C]-glucose for 45 min and formation of 2-deoxy[1-(14)C]-glucose-6-phosphate was measured. White adipocytes were incubated with D-[U-(14)C]-glucose for 1 h. TNFα and Il-6 secretion from white adipose tissue pieces were measured by enzyme-linked-immunoassay. In the absence of insulin, a high concentration (3 µM) of PAP-1 stimulated 2-deoxy[1-14C]-glucose uptake in soleus muscle of wild-type and obese mice by 30% and 40% respectively, and in adipocytes by 20% and 50% respectively. PAP-1 also stimulated glucose uptake by adipocytes at the lower concentration of 1 µM, but at 300 nM, which is still 150-fold higher than its EC50 value for inhibition of the Kv1.3 channel, it had no effect. In the presence of insulin, PAP-1 (3 µM) had a significant effect only in adipocytes from obese mice. PAP-1 (3 µM) reduced the secretion of TNFα by adipose tissue but had no effect on the secretion of IL-6. Expression of Kv1.1, Kv1.2, Kv1.3 and Kv1.5 was determined by RT-PCR. Kv1.3 and Kv1.5 mRNA were detected in liver, gastrocnemius muscle, soleus muscle and white adipose tissue from wild-type and ob/ob mice, except that Kv1.3 could not be detected in gastrocnemius muscle, nor Kv1.5 in liver, of wild-type mice. Expression of both genes was generally higher in liver and muscle of ob/ob mice compared to wild-type mice. Kv1.5 appeared to be expressed more highly than Kv1.3 in soleus muscle, adipose tissue and adipocytes of wild-type mice. Expression of Kv1.2 appeared to be similar to that of Kv1.3 in soleus muscle and adipose tissue, but Kv1.2 was undetectable in adipocytes. Kv1.1 could not be detected in soleus muscle, adipose tissue or adipocytes. We conclude that inhibition of Kv1 channels by PAP-1 stimulates glucose uptake by adipocytes and soleus muscle of wild-type and ob/ob mice, and reduces the secretion of TNFα by adipose tissue. However, these effects are more likely due to inhibition of Kv1.5 than to inhibition of Kv1.3 channels.
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Affiliation(s)
- Robert A Ngala
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Mohamed S Zaibi
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Kenneth Langlands
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Claire J Stocker
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Jonathan R S Arch
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Michael A Cawthorne
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
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8
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Ngala RA, Zaibi MS, Langlands K, Stocker CJ, Arch JRS, Cawthorne MA. Stimulation of glucose uptake in murine soleus muscle and adipocytes by 5-(4-phenoxybutoxy)psoralen ( PAP-1) may be mediated by Kv1.5 rather than Kv1.3. PeerJ 2014; 2:e614. [PMID: 25320682 PMCID: PMC4193404 DOI: 10.7717/peerj.614] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/17/2014] [Indexed: 01/08/2023] Open
Abstract
Kv1 channels are shaker-related potassium channels that influence insulin sensitivity. Kv1.3−/− mice are protected from diet-induced insulin resistance and some studies suggest that Kv1.3 inhibitors provide similar protection. However, it is unclear whether blockade of Kv1.3 in adipocytes or skeletal muscle increases glucose uptake. There is no evidence that the related channel Kv1.5 has any influence on insulin sensitivity and its expression in adipose tissue has not been reported. PAP-1 is a selective inhibitor of Kv1.3, with 23-fold, 32-fold and 125-fold lower potencies as an inhibitor of Kv1.5, Kv1.1 and Kv1.2 respectively. Soleus muscles from wild-type and genetically obese ob/ob mice were incubated with 2-deoxy[1-14C]-glucose for 45 min and formation of 2-deoxy[1-14C]-glucose-6-phosphate was measured. White adipocytes were incubated with D-[U-14C]-glucose for 1 h. TNFα and Il-6 secretion from white adipose tissue pieces were measured by enzyme-linked-immunoassay. In the absence of insulin, a high concentration (3 µM) of PAP-1 stimulated 2-deoxy[1-14C]-glucose uptake in soleus muscle of wild-type and obese mice by 30% and 40% respectively, and in adipocytes by 20% and 50% respectively. PAP-1 also stimulated glucose uptake by adipocytes at the lower concentration of 1 µM, but at 300 nM, which is still 150-fold higher than its EC50 value for inhibition of the Kv1.3 channel, it had no effect. In the presence of insulin, PAP-1 (3 µM) had a significant effect only in adipocytes from obese mice. PAP-1 (3 µM) reduced the secretion of TNFα by adipose tissue but had no effect on the secretion of IL-6. Expression of Kv1.1, Kv1.2, Kv1.3 and Kv1.5 was determined by RT-PCR. Kv1.3 and Kv1.5 mRNA were detected in liver, gastrocnemius muscle, soleus muscle and white adipose tissue from wild-type and ob/ob mice, except that Kv1.3 could not be detected in gastrocnemius muscle, nor Kv1.5 in liver, of wild-type mice. Expression of both genes was generally higher in liver and muscle of ob/ob mice compared to wild-type mice. Kv1.5 appeared to be expressed more highly than Kv1.3 in soleus muscle, adipose tissue and adipocytes of wild-type mice. Expression of Kv1.2 appeared to be similar to that of Kv1.3 in soleus muscle and adipose tissue, but Kv1.2 was undetectable in adipocytes. Kv1.1 could not be detected in soleus muscle, adipose tissue or adipocytes. We conclude that inhibition of Kv1 channels by PAP-1 stimulates glucose uptake by adipocytes and soleus muscle of wild-type and ob/ob mice, and reduces the secretion of TNFα by adipose tissue. However, these effects are more likely due to inhibition of Kv1.5 than to inhibition of Kv1.3 channels.
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Affiliation(s)
- Robert A Ngala
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Mohamed S Zaibi
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Kenneth Langlands
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Claire J Stocker
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Jonathan R S Arch
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
| | - Michael A Cawthorne
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham , Buckingham , UK
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Kundu-Raychaudhuri S, Chen YJ, Wulff H, Raychaudhuri SP. Kv1.3 in psoriatic disease: PAP-1, a small molecule inhibitor of Kv1.3 is effective in the SCID mouse psoriasis--xenograft model. J Autoimmun 2014; 55:63-72. [PMID: 25175978 DOI: 10.1016/j.jaut.2014.07.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [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: 03/09/2014] [Revised: 07/02/2014] [Accepted: 07/18/2014] [Indexed: 12/26/2022]
Abstract
Kv1.3 channels regulate the activation/proliferation of effector memory T cells and thus play a critical role in the pathogenesis of autoimmune diseases. Using a combination of immunohistochemistry, confocal microscopy, flow cytometry and electrophysiology methods we observed a significant enrichment of activated Kv1.3(+) memory T cells in psoriasis plaques and synovial fluid from patients with psoriasis/psoriatic arthritis (PsA) compared to non-lesional psoriatic skin, normal skin or peripheral blood lympho-mononuclear cells. In in vitro studies performed with lesional mononuclear cells or T cells derived from skin and joints of psoriatic disease, the small molecule Kv1.3 blocker PAP-1 dose-dependently inhibited proliferation and suppressed IL-2 and IFN-γ production. To further substantiate the pathologic role of Kv1.3 high TEM cells in psoriatic disease we tested whether PAP-1 is able to improve psoriatic disease pathology in the SCID mouse-psoriasis skin xenograft model. Following four weeks of daily treatment with 2% PAP-1 ointment we noticed about 50% reduction in the epidermal thickness (rete peg length) and the number of CD3(+) lymphocytes/mm(2) of dermis decreased by 85%. Vehicle treated and untreated plaques in contrast remained unchanged and showed no reduction in epidermis thickness and infiltrating CD3(+) T cells and HLA-DR(+) T cells. Based on these results we propose the development of Kv1.3 targeted topical immunotherapy for psoriasis and possibly for other inflammatory skin conditions, where effector memory T cells are involved in the pathogenesis.
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Affiliation(s)
- Smriti Kundu-Raychaudhuri
- VA Medical Center Sacramento, 10535 Hospital Way, Mather, CA 95655, USA; Department of Pharmacology, University of California Davis, School of Medicine, Davis, CA, USA
| | - Yi-Je Chen
- Department of Pharmacology, University of California Davis, School of Medicine, Davis, CA, USA
| | - Heike Wulff
- Department of Pharmacology, University of California Davis, School of Medicine, Davis, CA, USA
| | - Siba P Raychaudhuri
- Psoriasis Clinic, Department of Dermatology, VA Medical Center Sacramento, CA, USA; Division of Rheumatology, Allergy & Clinical Immunology, University of California Davis, School of Medicine, Davis, CA, USA.
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