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Chen CS, So EC, Wu SN. Modulating Hyperpolarization-Activated Cation Currents through Small Molecule Perturbations: Magnitude and Gating Control. Biomedicines 2023; 11:2177. [PMID: 37626674 PMCID: PMC10452073 DOI: 10.3390/biomedicines11082177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/10/2023] [Accepted: 07/27/2023] [Indexed: 08/27/2023] Open
Abstract
The hyperpolarization-activated cation current (Ih) exhibits a slowly activating time course of the current (Ih) when the cell membrane is hyperpolarized for an extended duration. It is involved in generating electrical activity in various excitable cells. Numerous structurally distinct compounds or herbal drugs have the potential to impact both the magnitude and gating kinetics of this current. Brivaracetam, a chemical analog of levetiracetam known to be a ligand for synaptic vesicle protein 2A, could directly suppress the Ih magnitude. Carisbamate, an anticonvulsant agent, not only inhibited the Ih amplitude but also reduced the strength of voltage-dependent hysteresis (Hys(V)) associated with Ih. Cilobradine, similar to ivabradine, inhibited the amplitude of Ih; however, it also suppressed the amplitude of delayed-rectifier K+ currents. Dexmedetomidine, an agonist of α2-adrenergic receptor, exerted a depressant action on Ih in a concentration-dependent fashion. Suppression of Ih amplitude was observed when GAL-021, a breathing control modulator, was present at a concentration exceeding 30 μM. Lutein, one of the few xanthophyll carotenoids, was able to suppress the Ih amplitude as well as to depress Hys(V)'s strength of Ih. Pirfenidone, a pyridine derivative known to be an anti-fibrotic agent, depressed the Ih magnitude in a concentration- and voltage-dependent fashion. Tramadol, a synthetic centrally active analgesic, was shown to reduce the Ih magnitude, independent of its interaction with opioid receptors. Various herbal drugs, including ent-kaurane-type diterpenoids from Croton tonkinensis, Ganoderma triterpenoids, honokiol, and pterostilbene, demonstrated efficacy in reducing the magnitude of Ih. Conversely, oxaliplatin, a platinum-based chemotherapeutic compound, was observed to effectively increase the Ih amplitude. Collectively, the regulatory effects of these compounds or herbal drugs on cellular function can be partly attributed to their perturbations on Ih.
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Affiliation(s)
- Cheng-Shih Chen
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan 70965, Taiwan; (C.-S.C.); (E.C.S.)
| | - Edmund Cheung So
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan 70965, Taiwan; (C.-S.C.); (E.C.S.)
| | - Sheng-Nan Wu
- School of Medicine, National Sun Yat Sen University College of Medicine, Kaohsiung 804, Taiwan
- Department of Medical Education & Research, An Nan Hospital, China Medical University, Tainan 70965, Taiwan
- Department of Physiology, National Cheng Kung University Medical College, Tainan 701, Taiwan
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Effect of Pterostilbene, a Natural Derivative of Resveratrol, in the Treatment of Colorectal Cancer through Top1/Tdp1-Mediated DNA Repair Pathway. Cancers (Basel) 2021; 13:cancers13164002. [PMID: 34439157 PMCID: PMC8391236 DOI: 10.3390/cancers13164002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Tyrosyl-DNA phosphodiesterase 1 (Tdp1) repairs the stalled Topoisomerase 1 (Top1)-DNA covalent complex. It is conceivable that Tdp1 inhibitors could act synergistically with Top1 inhibitors to enhance the effect of Top1 poisons. This study identified pterostilbene (PTE) and resveratrol (RE) to suppress these two proteins by binding to their active center. PTE and RE could inhibit the proliferation of various colorectal cancer cells and decrease Top1 and Tdp1 contents and mRNA expression in wild-type, constructed Tdp1 overexpressing CL187, Top1- or Tdp1- silenced CL187 cell lines. PTE exhibited better antitumor activity and safety in subcutaneous CL187 transplantion model and orthotopic transplantation model. PTE had no significant inhibitory effect on non-tumor cell proliferation in vitro and would not induce damage to liver, kidney, and other major organs. Abstract Topoisomerase 1 (Top1) inhibitor is an effective anticancer drug, but several factors limit its clinical application such as drug inactivation, tyrosyl-DNA phosphodiesterase 1 (Tdp1)-mediated tumor drug resistance, and its toxicity. Our previous study identified pterostilbene (PTE) and resveratrol (RE) to suppress these two proteins by binding to their active center. PTE and RE could inhibit the proliferation of various colorectal cancer cells, induce cell apoptosis, and make cell cycle stay in G2/M phase in vitro. PTE and RE could decrease Top1 and Tdp1 contents and mRNA expression in wild-type, constructed Tdp1 overexpressing CL187, Top1- or Tdp1- silenced CL187 cell lines. PTE exhibited excellent antitumor activity in subcutaneous CL187 transplantation model (TGI = 79.14 ± 2.85%, 200 mg/kg, i.p.) and orthotopic transplantation model (TGI = 76.57 ± 6.34%, 100 mg/kg, i.p.; TGI = 72.79 ± 4.06%, 500 mg/kg, i.g.) without significant toxicity. PTE had no significant inhibitory effect on non-tumor cell proliferation in vitro and would not induce damage to liver, kidney, and other major organs. Overall, PTE and RE can inhibit the activity of Top1 enzyme and inhibit the DNA damage repair pathway mediated by Top1/Tdp1, and can effectively inhibit colorectal cancer development with low toxicity, thus they have great potential to be developed into a new generation of anti-tumor drugs.
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Hung TY, Huang CW, Wu SN. High ability of zileuton ((±)-1-(1-benzo[b]thien-2-ylethyl)-1-hydroxyurea) to stimulate I K(Ca) but suppress I K(DR) and I K(M) independently of 5-lipoxygenase inhibition. Eur J Pharmacol 2020; 887:173482. [PMID: 32795513 DOI: 10.1016/j.ejphar.2020.173482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 12/16/2022]
Abstract
Zileuton (Zyflo®) is regarded to be an inhibitor of 5-lipoxygenase. Although its effect on Ca2+-activated K+ currents has been reported, its overall ionic effects on neurons are uncertain. In whole-cell current recordings, zileuton increased the amplitude of Ca2+-activated K+ currents with an EC50 of 3.2 μM in pituitary GH3 lactotrophs. Furthermore, zileuton decreased the amplitudes of both delayed-rectifier K+ current (IK(DR)) and M-type K+ current (IK(M)). Conversely, no modification of hyperpolarization-activated cation current (Ih) was demonstrated in its presence of zileuton, although the subsequent addition of cilobradine effectively suppressed the current. In inside-out current recordings, the addition of zileuton to the bath increased the probability of large-conductance Ca2+-activated K+ (BKCa) channels; however, the subsequent addition of GAL-021 effectively reversed the stimulation of channel activity. The kinetic analyses showed an evident shortening in the slow component of mean closed time of BKCa channels in the presence of zileuton, with minimal change in mean open time or that in the fast component of mean closed time. The elevation of BKCa channels caused by zileuton was also observed in hippocampal mHippoE-14 neurons, without any modification of single-channel amplitude. In conclusion, except for its suppression of 5-lipoxygenase, our results indicate that zileuton does not exclusively act on BKCa channels, and its inhibitory effects on IK(DR) and IK(M) may combine to exert strong influence on the functional activities of electrically excitable cells in vivo.
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Affiliation(s)
- Te-Yu Hung
- Department of Pediatrics, Chi-Mei Medical Center, Tainan, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan; Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City, Taiwan.
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Chan MH, Chen HH, Lo YC, Wu SN. Effectiveness in the Block by Honokiol, a Dimerized Allylphenol from Magnolia Officinalis, of Hyperpolarization-Activated Cation Current and Delayed-Rectifier K + Current. Int J Mol Sci 2020; 21:ijms21124260. [PMID: 32549398 PMCID: PMC7352210 DOI: 10.3390/ijms21124260] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/03/2020] [Accepted: 06/09/2020] [Indexed: 12/22/2022] Open
Abstract
Background: Honokiol (HNK), a dimer of allylphenol obtained from the bark of Magnolia officinalis was demonstrated to exert an array of biological actions in different excitable cell types. However, whether or how this compound can lead to any perturbations on surface-membrane ionic currents remains largely unknown. Methods: We used the patch clamp method and found that addition of HNK effectively depressed the density of macroscopic hyperpolarization-activated cation currents (Ih) in pituitary GH3 cells in a concentration-, time- and voltage-dependent manner. By the use of a two-step voltage protocol, the presence of HNK (10 μM) shifted the steady-state activation curve of Ih density along the voltage axis to a more negative potential by approximately 11 mV, together with no noteworthy modification in the gating charge of the current. Results: The voltage-dependent hysteresis of Ih density elicited by long-lasting triangular ramp pulse was attenuated by the presence of HNK. The HNK addition also diminished the magnitude of deactivating Ih density elicited by ramp-up depolarization with varying durations. The effective half-maximal concentration (IC50) value needed to inhibit the density of Ih or delayed rectifier K+ current identified in GH3 cells was estimated to be 2.1 or 6.8 μM, respectively. In cell-attached current recordings, HNK decreased the frequency of spontaneous action currents. In Rolf B1.T olfactory sensory neurons, HNK was also observed to decrease Ih density in a concentration-dependent manner. Conclusions: The present study highlights the evidence revealing that HNK has the propensity to perturb these ionic currents and that the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel is proposed to be a potential target for the in vivo actions of HNK and its structurally similar compounds.
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Affiliation(s)
- Ming-Huan Chan
- Institute of Neuroscience, National Chengchi University, Taipei 11605, Taiwan; (M.-H.C.); (H.-H.C.)
| | - Hwei-Hsien Chen
- Institute of Neuroscience, National Chengchi University, Taipei 11605, Taiwan; (M.-H.C.); (H.-H.C.)
- Center of Neuropsychiatric Research, National Health Research Institutes, Miaoli County 35053, Taiwan
| | - Yi-Ching Lo
- Department of Pharmacology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan
- Correspondence:
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Wang C, Li L, Jiang J, Li L, Li J, Xu C, Jin S, Zhu L, Yan G. Pterostilbene Inhibits FcεRI Signaling through Activation of the LKB1/AMPK Pathway in Allergic Response. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:3456-3465. [PMID: 32096633 DOI: 10.1021/acs.jafc.9b07126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, the role and mechanism of pterostilbene (Pts) in mast cell degranulation in vitro and in vivo were investigated. The results showed that Pts inhibited mast cell-mediated local passive allergic reactions in mice. In addition, treatment with Pts reduced both histamine release and calcium influx in rat peritoneal mast cells and RBL-2H3 cells and reduced IgE-mediated mast cell activation. Furthermore, the mechanism underlying Pts inhibition of mast cell signaling was probed via studying the effects of Pts on liver kinase B1 (LKB1), including the use of the LKB1 activator metformin and siRNA knockdown of LKB1. The data showed that Pts reduced the release of inflammatory mediators such as tumor necrosis factor-α, interleukin-6, leukotriene C4, and prostaglandin D2 in mast cells by activating the LKB1/adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway. Furthermore, Pts inhibited phosphorylation of FcεRI and FcεRI-mediated degranulation in RBL-2H3 cells. These effects were attenuated after LKB1 knockdown. Taken together, Pts could inhibit FcεRI signaling through activation of the LKB1/AMPK signaling pathway in IgE-mediated mast cell activation. Thus, Pts might be an effective therapeutic agent for mast cell-mediated allergic diseases.
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Affiliation(s)
- Chongyang Wang
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
| | - Liangchang Li
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
| | - Jingzhi Jiang
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
| | - Li Li
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
| | - Junfeng Li
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
| | - Chang Xu
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
| | - Shan Jin
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
- Department of Dermatology, Yanbian University Hospital, Yanji 133002, P. R. China
| | - Lianhua Zhu
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
- Department of Dermatology, Yanbian University Hospital, Yanji 133002, P. R. China
| | - Guanghai Yan
- Department of Anatomy, Histology and Embryology, Medical College, Yanbian University, Yanji 133002, P. R. China
- Jilin Key Laboratory of Anaphylactic Disease, Yanbian University, Yanji 133000, P. R. China
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