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Wang W, Cheng Z, Wang X, An Q, Huang K, Dai Y, Meng Q, Zhang Y. Lactoferrin deficiency during lactation increases the risk of depressive-like behavior in adult mice. BMC Biol 2023; 21:242. [PMID: 37907907 PMCID: PMC10617225 DOI: 10.1186/s12915-023-01748-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 10/24/2023] [Indexed: 11/02/2023] Open
Abstract
BACKGROUND Lactoferrin is an active protein in breast milk that plays an important role in the growth and development of infants and is implicated as a neuroprotective agent. The incidence of depression is currently increasing, and it is unclear whether the lack of lactoferrin during lactation affects the incidence of depressive-like behavior in adulthood. RESULTS Lack of lactoferrin feeding during lactation affected the barrier and innate immune functions of the intestine, disrupted the intestinal microflora, and led to neuroimmune dysfunction and neurodevelopmental delay in the hippocampus. When exposed to external stimulation, adult lactoferrin feeding-deficient mice presented with worse depression-like symptoms; the mechanisms involved were activation of the LPS-TLR4 signalling pathway in the intestine and hippocampus, reduced BDNF-CREB signaling pathway in hippocampus, increased abundance of depression-related bacteria, and decreased abundance of beneficial bacteria. CONCLUSIONS Overall, our findings reveal that lactoferrin feeding deficient during lactation can increase the risk of depressive-like behavior in adults. The mechanism is related to the regulatory effect of lactoferrin on the development of the "microbial-intestinal-brain" axis.
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Affiliation(s)
- Wenli Wang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhimei Cheng
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Xiong Wang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Qin An
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Kunlun Huang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Yunping Dai
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Qingyong Meng
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yali Zhang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
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2
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Labbaf A, Dellin M, Komadowski M, Chetkovich DM, Decher N, Pape HC, Seebohm G, Budde T, Zobeiri M. Characterization of Kv1.2-mediated outward current in TRIP8b-deficient mice. Biol Chem 2023; 404:291-302. [PMID: 36852869 DOI: 10.1515/hsz-2023-0116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/16/2023] [Indexed: 03/01/2023]
Abstract
Tonic current through hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels is influencing neuronal firing properties and channel function is strongly influenced by the brain-specific auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). Since Kv1.2 channels and TRIP8b were also suggested to interact, we assessed brain Kv1.2 mRNA and protein expression as well as the reduction of K+ outward currents by Kv1.2-blocking compounds (Psora-4; tityustoxin-Kα, TsTX-Kα) in different brain areas of TRIP8b-deficient (TRIP8b -/- ) compared to wildtype (WT) mice. We found that transcription levels of Kv1.2 channels were not different between genotypes. Furthermore, Kv1.2 current amplitude was not affected upon co-expression with TRIP8b in oocytes. However, Kv1.2 immunofluorescence was stronger in dendritic areas of cortical and hippocampal neurons. Furthermore, the peak net outward current was increased and the inactivation of the Psora-4-sensitive current component was less pronounced in cortical neurons in TRIP8b -/- mice. In current clamp recordings, application of TsTX increased the excitability of thalamocortical (TC) neurons with increased number of elicited action potentials upon step depolarization. We conclude that TRIP8b may not preferentially influence the amplitude of current through Kv1.2 channels but seems to affect current inactivation and channel localization. In TRIP8b -/- a compensatory upregulation of other Kv channels was observed.
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Affiliation(s)
- Afsaneh Labbaf
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
| | - Maurice Dellin
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
| | - Marlene Komadowski
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Dane M Chetkovich
- Medical Center, Department of Neurology, Vanderbilt University, Nashville, TN, USA
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Hans-Chrisitian Pape
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
| | - Mehrnoush Zobeiri
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149 Münster, Germany
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3
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Abbott GW. Kv Channel Ancillary Subunits: Where Do We Go from Here? Physiology (Bethesda) 2022; 37:0. [PMID: 35797055 PMCID: PMC9394777 DOI: 10.1152/physiol.00005.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 01/10/2023] Open
Abstract
Voltage-gated potassium (Kv) channels each comprise four pore-forming α-subunits that orchestrate essential duties such as voltage sensing and K+ selectivity and conductance. In vivo, however, Kv channels also incorporate regulatory subunits-some Kv channel specific, others more general modifiers of protein folding, trafficking, and function. Understanding all the above is essential for a complete picture of the role of Kv channels in physiology and disease.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
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4
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Kessi M, Peng J, Duan H, He H, Chen B, Xiong J, Wang Y, Yang L, Wang G, Kiprotich K, Bamgbade OA, He F, Yin F. The Contribution of HCN Channelopathies in Different Epileptic Syndromes, Mechanisms, Modulators, and Potential Treatment Targets: A Systematic Review. Front Mol Neurosci 2022; 15:807202. [PMID: 35663267 PMCID: PMC9161305 DOI: 10.3389/fnmol.2022.807202] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Background Hyperpolarization-activated cyclic nucleotide-gated (HCN) current reduces dendritic summation, suppresses dendritic calcium spikes, and enables inhibitory GABA-mediated postsynaptic potentials, thereby suppressing epilepsy. However, it is unclear whether increased HCN current can produce epilepsy. We hypothesized that gain-of-function (GOF) and loss-of-function (LOF) variants of HCN channel genes may cause epilepsy. Objectives This systematic review aims to summarize the role of HCN channelopathies in epilepsy, update genetic findings in patients, create genotype–phenotype correlations, and discuss animal models, GOF and LOF mechanisms, and potential treatment targets. Methods The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, for all years until August 2021. Results We identified pathogenic variants of HCN1 (n = 24), HCN2 (n = 8), HCN3 (n = 2), and HCN4 (n = 6) that were associated with epilepsy in 74 cases (43 HCN1, 20 HCN2, 2 HCN3, and 9 HCN4). Epilepsy was associated with GOF and LOF variants, and the mechanisms were indeterminate. Less than half of the cases became seizure-free and some developed drug-resistant epilepsy. Of the 74 cases, 12 (16.2%) died, comprising HCN1 (n = 4), HCN2 (n = 2), HCN3 (n = 2), and HCN4 (n = 4). Of the deceased cases, 10 (83%) had a sudden unexpected death in epilepsy (SUDEP) and 2 (16.7%) due to cardiopulmonary failure. SUDEP affected more adults (n = 10) than children (n = 2). HCN1 variants p.M234R, p.C329S, p.V414M, p.M153I, and p.M305L, as well as HCN2 variants p.S632W and delPPP (p.719–721), were associated with different phenotypes. HCN1 p.L157V and HCN4 p.R550C were associated with genetic generalized epilepsy. There are several HCN animal models, pharmacological targets, and modulators, but precise drugs have not been developed. Currently, there are no HCN channel openers. Conclusion We recommend clinicians to include HCN genes in epilepsy gene panels. Researchers should explore the possible underlying mechanisms for GOF and LOF variants by identifying the specific neuronal subtypes and neuroanatomical locations of each identified pathogenic variant. Researchers should identify specific HCN channel openers and blockers with high binding affinity. Such information will give clarity to the involvement of HCN channelopathies in epilepsy and provide the opportunity to develop targeted treatments.
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Affiliation(s)
- Miriam Kessi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Department of Pediatrics, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Haolin Duan
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Hailan He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ying Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Guoli Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Karlmax Kiprotich
- Department of Epidemiology and Medical Statistics, School of Public Health, Moi University, Eldoret, Kenya
| | - Olumuyiwa A. Bamgbade
- Department of Anesthesiology and Pharmacology, University of British Columbia, Vancouver, BC, Canada
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- *Correspondence: Fei Yin
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5
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Dwivedi D, Bhalla US. Physiology and Therapeutic Potential of SK, H, and M Medium AfterHyperPolarization Ion Channels. Front Mol Neurosci 2021; 14:658435. [PMID: 34149352 PMCID: PMC8209339 DOI: 10.3389/fnmol.2021.658435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/13/2021] [Indexed: 12/19/2022] Open
Abstract
SK, HCN, and M channels are medium afterhyperpolarization (mAHP)-mediating ion channels. The three channels co-express in various brain regions, and their collective action strongly influences cellular excitability. However, significant diversity exists in the expression of channel isoforms in distinct brain regions and various subcellular compartments, which contributes to an equally diverse set of specific neuronal functions. The current review emphasizes the collective behavior of the three classes of mAHP channels and discusses how these channels function together although they play specialized roles. We discuss the biophysical properties of these channels, signaling pathways that influence the activity of the three mAHP channels, various chemical modulators that alter channel activity and their therapeutic potential in treating various neurological anomalies. Additionally, we discuss the role of mAHP channels in the pathophysiology of various neurological diseases and how their modulation can alleviate some of the symptoms.
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Affiliation(s)
- Deepanjali Dwivedi
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India.,Department of Neurobiology, Harvard Medical School, Boston, MA, United States.,Stanley Center at the Broad, Cambridge, MA, United States
| | - Upinder S Bhalla
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India
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6
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Lussier Y, Fürst O, Fortea E, Leclerc M, Priolo D, Moeller L, Bichet DG, Blunck R, D'Avanzo N. Disease-linked mutations alter the stoichiometries of HCN-KCNE2 complexes. Sci Rep 2019; 9:9113. [PMID: 31235733 PMCID: PMC6591248 DOI: 10.1038/s41598-019-45592-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 06/11/2019] [Indexed: 12/21/2022] Open
Abstract
The four hyperpolarization-activated cylic-nucleotide gated (HCN) channel isoforms and their auxiliary subunit KCNE2 are important in the regulation of peripheral and central neuronal firing and the heartbeat. Disruption of their normal function has been implicated in cardiac arrhythmias, peripheral pain, and epilepsy. However, molecular details of the HCN-KCNE2 complexes are unknown. Using single-molecule subunit counting, we determined that the number of KCNE2 subunits in complex with the pore-forming subunits of human HCN channels differs with each HCN isoform and is dynamic with respect to concentration. These interactions can be altered by KCNE2 gene-variants with functional implications. The results provide an additional consideration necessary to understand heart rhythm, pain, and epileptic disorders.
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Affiliation(s)
- Yoann Lussier
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada
| | - Oliver Fürst
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada
| | - Eva Fortea
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada
| | - Marc Leclerc
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada
| | - Dimitri Priolo
- Department of Physics, Université de Montréal, Montréal, Canada
| | - Lena Moeller
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Canada
| | - Daniel G Bichet
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada
| | - Rikard Blunck
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada.,Department of Physics, Université de Montréal, Montréal, Canada
| | - Nazzareno D'Avanzo
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada. .,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Canada.
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7
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Luo P, He G, Liu D. HCN channels: New targets for the design of an antidepressant with rapid effects. J Affect Disord 2019; 245:764-770. [PMID: 30448761 DOI: 10.1016/j.jad.2018.11.081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 10/22/2018] [Accepted: 11/11/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Major depressive disorder (MDD) is a prevalent neuropsychiatric disease that carries a staggering global burden. Although numerous antidepressants are available on the market, unfortunately, many patients die by committing suicide as a result of the therapeutic lag between treatment initiation and the improvement of depressive symptoms. This therapeutic lag highlights the need for new antidepressants that provide rapid relief of depressive symptoms. METHOD In this review, we discuss the seminal researches on hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in animal models of depression and highlight the substantial evidence supporting the development of rapid-acting antidepressants targeting HCN channels. RESULTS HCN channels are associated with the risk of depression and targeting HCN channels or its auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b) function may exert a rapid antidepressant-like effect. CONCLUSIONS Compounds acting on HCN subunits or the TRIP8b-HCN interaction site may be excellent candidates for development into effective drugs with rapid antidepressant action.
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Affiliation(s)
- Pan Luo
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - GuoFang He
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Dong Liu
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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8
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Persistent "Sag" in Prefrontal Cortex Function following Adolescent Binge Drinking. J Neurosci 2018; 38:9615-9617. [PMID: 30404940 DOI: 10.1523/jneurosci.1755-18.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/07/2018] [Accepted: 09/12/2018] [Indexed: 11/21/2022] Open
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9
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Zhu M, Idikuda VK, Wang J, Wei F, Kumar V, Shah N, Waite CB, Liu Q, Zhou L. Shank3-deficient thalamocortical neurons show HCN channelopathy and alterations in intrinsic electrical properties. J Physiol 2018; 596:1259-1276. [PMID: 29327340 DOI: 10.1113/jp275147] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 01/04/2018] [Indexed: 01/11/2023] Open
Abstract
KEY POINTS Shank3 increases the HCN channel surface expression in heterologous expression systems. Shank3Δ13-16 deficiency causes significant reduction in HCN2 expression and Ih current amplitude in thalamocortical (TC) neurons. Shank3Δ13-16 - but not Shank3Δ4-9 -deficient TC neurons share changes in basic electrical properties which are comparable to those of HCN2-/- TC neurons. HCN channelopathy may critically mediate events downstream from Shank3 deficiency. ABSTRACT SHANK3 is a scaffolding protein that is highly enriched in excitatory synapses. Mutations in the SHANK3 gene have been linked to neuropsychiatric disorders especially the autism spectrum disorders. SHANK3 deficiency is known to cause impairments in synaptic transmission, but its effects on basic neuronal electrical properties that are more localized to the soma and proximal dendrites remain unclear. Here we confirmed that in heterologous expression systems two different mouse Shank3 isoforms, Shank3A and Shank3C, significantly increase the surface expression of the mouse hyperpolarization-activated, cyclic-nucleotide-gated (HCN) channel. In Shank3Δ13-16 knockout mice, which lack exons 13-16 in the Shank3 gene (both Shank3A and Shank3C are removed) and display a severe behavioural phenotype, the expression of HCN2 is reduced to an undetectable level. The thalamocortical (TC) neurons from the ventrobasal (VB) complex of Shank3Δ13-16 mice demonstrate reduced Ih current amplitude and correspondingly increased input resistance, negatively shifted resting membrane potential, and abnormal spike firing in both tonic and burst modes. Impressively, these changes closely resemble those of HCN2-/- TC neurons but not of the TC neurons from Shank3Δ4-9 mice, which lack exons 4-9 in the Shank3 gene (Shank3C still exists) and demonstrate moderate behavioural phenotypes. Additionally, Shank3 deficiency increases the ratio of excitatory/inhibitory balance in VB neurons but has a limited impact on the electrical properties of connected thalamic reticular (RTN) neurons. These results provide new understanding about the role of HCN channelopathy in mediating detrimental effects downstream from Shank3 deficiency.
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Affiliation(s)
- Mengye Zhu
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.,Department of Pain Clinic, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Vinay Kumar Idikuda
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Jianbing Wang
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.,Department of Anesthesiology, Jiangxi Cancer Hospital, Nanchang, Jiangxi, China
| | - Fusheng Wei
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.,Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Virang Kumar
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Nikhil Shah
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Christopher B Waite
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Qinglian Liu
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Lei Zhou
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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10
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González B, González C, Bisagno V, Urbano FJ. EFFECTS OF METHAMPHETAMINE ON LOCOMOTOR ACTIVITY AND THALAMIC GENE EXPRESSION IN LEPTIN-DEFICIENT OBESE MICE. ACTA ACUST UNITED AC 2017; 2. [PMID: 28920084 DOI: 10.15761/tbr.1000112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Leptin is an adipose-derived hormone that regulates energy balance. Leptin receptors are expressed in extrahypothalamic sites and several reports showed that leptin can influence feeding and locomotor behavior via direct actions on dopaminergic neurons. The leptin deficient mouse (ob/ob) has been used as an animal model of blunted leptin action, and presents with obesity and mild type 2 diabetes. We used ob/ob mice to study the effect of repeated 7-day methamphetamine (METH) administration analyzing locomotion, behavioral sensitization, and somatosensory thalamic mRNA expression of voltage-gated calcium channels and glutamatergic receptors using RT-PCR. We observed reduced METH-mediated responses in ob/ob mice associated with enhanced in mRNA expression of key voltage-gated and glutamate receptors in the somatosensory thalamus. Results described here are important for understanding the control of locomotion and thalamocortical excitability by leptin.
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Affiliation(s)
- Betina González
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Ciudad Autónoma de Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad Autónoma de Buenos Aires.,Universidad de Buenos Aires, Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Farmacológicas (ININFA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Candela González
- Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina
| | - Verónica Bisagno
- Universidad de Buenos Aires, Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Farmacológicas (ININFA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Francisco J Urbano
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Ciudad Autónoma de Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad Autónoma de Buenos Aires
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11
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Hyperpolarization-activated current I h in mouse trigeminal sensory neurons in a transgenic mouse model of familial hemiplegic migraine type-1. Neuroscience 2017; 351:47-64. [DOI: 10.1016/j.neuroscience.2017.03.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/15/2017] [Accepted: 03/20/2017] [Indexed: 12/19/2022]
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12
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Larimore J, Zlatic SA, Arnold M, Singleton KS, Cross R, Rudolph H, Bruegge MV, Sweetman A, Garza C, Whisnant E, Faundez V. Dysbindin Deficiency Modifies the Expression of GABA Neuron and Ion Permeation Transcripts in the Developing Hippocampus. Front Genet 2017; 8:28. [PMID: 28344592 PMCID: PMC5344932 DOI: 10.3389/fgene.2017.00028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/20/2017] [Indexed: 12/25/2022] Open
Abstract
The neurodevelopmental factor dysbindin is required for synapse function and GABA interneuron development. Dysbindin protein levels are reduced in the hippocampus of schizophrenia patients. Mouse dysbindin genetic defects and other mouse models of neurodevelopmental disorders share defective GABAergic neurotransmission and, in several instances, a loss of parvalbumin-positive interneuron phenotypes. This suggests that mechanisms downstream of dysbindin deficiency, such as those affecting GABA interneurons, could inform pathways contributing to or ameliorating diverse neurodevelopmental disorders. Here we define the transcriptome of developing wild type and dysbindin null Bloc1s8sdy/sdy mouse hippocampus in order to identify mechanisms downstream dysbindin defects. The dysbindin mutant transcriptome revealed previously reported GABA parvalbumin interneuron defects. However, the Bloc1s8sdy/sdy transcriptome additionally uncovered changes in the expression of molecules controlling cellular excitability such as the cation-chloride cotransporters NKCC1, KCC2, and NCKX2 as well as the potassium channel subunits Kcne2 and Kcnj13. Our results suggest that dysbindin deficiency phenotypes, such as GABAergic defects, are modulated by the expression of molecules controlling the magnitude and cadence of neuronal excitability.
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Affiliation(s)
| | | | - Miranda Arnold
- Department of Biology, Agnes-Scott College, Decatur, GA, USA
| | | | - Rebecca Cross
- Department of Biology, Agnes-Scott College, Decatur, GA, USA
| | - Hannah Rudolph
- Department of Biology, Agnes-Scott College, Decatur, GA, USA
| | | | - Andrea Sweetman
- Department of Biology, Agnes-Scott College, Decatur, GA, USA
| | - Cecilia Garza
- Department of Biology, Agnes-Scott College, Decatur, GA, USA
| | - Eli Whisnant
- Department of Biology, Agnes-Scott College, Decatur, GA, USA
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, GA, USA
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Regulation of human cardiac potassium channels by full-length KCNE3 and KCNE4. Sci Rep 2016; 6:38412. [PMID: 27922120 PMCID: PMC5138848 DOI: 10.1038/srep38412] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/09/2016] [Indexed: 12/23/2022] Open
Abstract
Voltage-gated potassium (Kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane KCNE subunits. After recently uncovering novel, N-terminally extended (L) KCNE3 and KCNE4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac Kv channel α subunits expressed in Xenopus laevis oocytes. As previously reported for short isoforms KCNE3S and KCNE4S, KCNE3L inhibited hERG; KCNE4L inhibited Kv1.1; neither form regulated the HCN1 pacemaker channel. Unlike KCNE4S, KCNE4L was a potent inhibitor of Kv4.2 and Kv4.3; co-expression of cytosolic β subunit KChIP2, which regulates Kv4 channels in cardiac myocytes, partially relieved Kv4.3 but not Kv4.2 inhibition. Inhibition of Kv4.2 and Kv4.3 by KCNE3L was weaker, and its inhibition of Kv4.2 abolished by KChIP2. KCNE3L and KCNE4L also exhibited subunit-specific effects on Kv4 channel complex inactivation kinetics, voltage dependence and recovery. Further supporting the potential physiological significance of the robust functional effects of KCNE4L on Kv4 channels, KCNE4L protein was detected in human atrium, where it co-localized with Kv4.3. The findings establish functional effects of novel human cardiac-expressed KCNE isoforms and further contribute to our understanding of the potential mechanisms influencing cardiomyocyte repolarization.
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Dissection of partial 21q monosomy in different phenotypes: clinical and molecular characterization of five cases and review of the literature. Mol Cytogenet 2016; 9:21. [PMID: 27625702 PMCID: PMC5020505 DOI: 10.1186/s13039-016-0230-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 02/15/2016] [Indexed: 11/24/2022] Open
Abstract
Background Partial deletion of chromosome 21q is a very rare chromosomal abnormality associated with highly variable phenotypes, such as facial dysmorphic features, heart defects, seizures, psychomotor delay, and severe to mild intellectual disability, depending on the location and size of deletions. So far, three broad deletion regions of 21q have been correlated with the clinical phenotype. Results We described the clinical and genetic features of three family members (father and two siblings) and other two unrelated patients with very wide range in age of diagnosis. All of them showed intellectual disability with very variable symptoms, from mild to severe, and carried 21q interstitial deletions with different sizes and position, as detected by conventional karyotype and array-CGH. Conclusions Our study provided additional cases of partial 21q deletions, allowing to better delineate the genotype-phenotype correlations. In contrast to previous observations, we showed that deletions of the 21q proximal region are not necessarily associated with severe phenotypes and, therefore, that mild phenotypes are not exclusively related to distal deletions. To the best of our knowledge, this is the first report showing 21q deletions in adult patients associated with mild phenotypes, mainly consisting of neurobehavioral abnormalities, such as obsessive-compulsive disorders, poor social interactions and vulnerability to psychosis.
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15
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Sárvári M, Kalló I, Hrabovszky E, Solymosi N, Rodolosse A, Vastagh C, Auer H, Liposits Z. Hippocampal Gene Expression Is Highly Responsive to Estradiol Replacement in Middle-Aged Female Rats. Endocrinology 2015; 156:2632-45. [PMID: 25924104 DOI: 10.1210/en.2015-1109] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the hippocampus, estrogens are powerful modulators of neurotransmission, synaptic plasticity and neurogenesis. In women, menopause is associated with increased risk of memory disturbances, which can be attenuated by timely estrogen therapy. In animal models of menopause, 17β-estradiol (E2) replacement improves hippocampus-dependent spatial memory. Here, we explored the effect of E2 replacement on hippocampal gene expression in a rat menopause model. Middle-aged ovariectomized female rats were treated continuously for 29 days with E2, and then, the hippocampal transcriptome was investigated with Affymetrix expression arrays. Microarray data were analyzed by Bioconductor packages and web-based softwares, and verified with quantitative PCR. At standard fold change selection criterion, 156 genes responded to E2. All alterations but 4 were transcriptional activation. Robust activation (fold change > 10) occurred in the case of transthyretin, klotho, claudin 2, prolactin receptor, ectodin, coagulation factor V, Igf2, Igfbp2, and sodium/sulfate symporter. Classification of the 156 genes revealed major groups, including signaling (35 genes), metabolism (31 genes), extracellular matrix (17 genes), and transcription (16 genes). We selected 33 genes for further studies, and all changes were confirmed by real-time PCR. The results suggest that E2 promotes retinoid, growth factor, homeoprotein, neurohormone, and neurotransmitter signaling, changes metabolism, extracellular matrix composition, and transcription, and induces protective mechanisms via genomic effects. We propose that these mechanisms contribute to effects of E2 on neurogenesis, neural plasticity, and memory functions. Our findings provide further support for the rationale to develop safe estrogen receptor ligands for the maintenance of cognitive performance in postmenopausal women.
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Affiliation(s)
- Miklós Sárvári
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Imre Kalló
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Erik Hrabovszky
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Norbert Solymosi
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Annie Rodolosse
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Csaba Vastagh
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Herbert Auer
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
| | - Zsolt Liposits
- Laboratory of Endocrine Neurobiology (M.S., I.K., E.H., C.V., Z.L.), Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Faculty of Information Technology and Bionics (I.K., Z.L.), Pázmány Péter Catholic University, 1083 Budapest, Hungary; Faculty of Veterinary Science (N.S.), Szent István University, 1078 Budapest, Hungary; Functional Genomics Core (A.R.), Institute for Research in Biomedicine, 08028 Barcelona, Spain; and Functional Genomics Consulting (H.A.), 08780 Palleja, Spain
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16
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The KCNE2 K⁺ channel regulatory subunit: Ubiquitous influence, complex pathobiology. Gene 2015; 569:162-72. [PMID: 26123744 DOI: 10.1016/j.gene.2015.06.061] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/15/2015] [Accepted: 06/23/2015] [Indexed: 02/05/2023]
Abstract
The KCNE single-span transmembrane subunits are encoded by five-member gene families in the human and mouse genomes. Primarily recognized for co-assembling with and functionally regulating the voltage-gated potassium channels, the broad influence of KCNE subunits in mammalian physiology belies their small size. KCNE2 has been widely studied since we first discovered one of its roles in the heart and its association with inherited and acquired human Long QT syndrome. Since then, physiological analyses together with human and mouse genetics studies have uncovered a startling array of functions for KCNE2, in the heart, stomach, thyroid and choroid plexus. The other side of this coin is the variety of interconnected disease manifestations caused by KCNE2 disruption, involving both excitable cells such as cardiomyocytes, and non-excitable, polarized epithelia. Kcne2 deletion in mice has been particularly instrumental in illustrating the potential ramifications within a monogenic arrhythmia syndrome, with removal of one piece revealing the unexpected complexity of the puzzle. Here, we review current knowledge of the function and pathobiology of KCNE2.
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DiFrancesco JC, DiFrancesco D. Dysfunctional HCN ion channels in neurological diseases. Front Cell Neurosci 2015; 6:174. [PMID: 25805968 PMCID: PMC4354400 DOI: 10.3389/fncel.2015.00071] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/18/2015] [Indexed: 11/25/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed as four different isoforms (HCN1-4) in the heart and in the central and peripheral nervous systems. HCN channels are activated by membrane hyperpolarization at voltages close to resting membrane potentials and carry the hyperpolarization-activated current, dubbed If (funny current) in heart and Ih in neurons. HCN channels contribute in several ways to neuronal activity and are responsible for many important cellular functions, including cellular excitability, generation, and modulation of rhythmic activity, dendritic integration, transmission of synaptic potentials, and plasticity phenomena. Because of their role, defective HCN channels are natural candidates in the search for potential causes of neurological disorders in humans. Several data, including growing evidence that some forms of epilepsy are associated with HCN mutations, support the notion of an involvement of dysfunctional HCN channels in different experimental models of the disease. Additionally, some anti-epileptic drugs are known to modify the activity of the Ih current. HCN channels are widely expressed in the peripheral nervous system and recent evidence has highlighted the importance of the HCN2 isoform in the transmission of pain. HCN channels are also present in the midbrain system, where they finely regulate the activity of dopaminergic neurons, and a potential role of these channels in the pathogenesis of Parkinson’s disease has recently emerged. The function of HCN channels is regulated by specific accessory proteins, which control the correct expression and modulation of the neuronal Ih current. Alteration of these proteins can severely interfere with the physiological channel function, potentially predisposing to pathological conditions. In this review we address the present knowledge of the association between HCN dysfunctions and neurological diseases, including clinical, genetic, and physiopathological aspects.
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Affiliation(s)
- Jacopo C DiFrancesco
- Department of Neurophysiology, Foundation Neurological Institute C. Besta Milano, Italy ; Department of Neurology, San Gerardo Hospital and Laboratory of Neurobiology, Milan Center for Neuroscience, University of Milano-Bicocca Monza, Italy
| | - Dario DiFrancesco
- The PaceLab, Department of Biosciences, University of Milano Milano, Italy
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Krenz WDC, Rodgers EW, Baro DJ. Tonic 5nM DA stabilizes neuronal output by enabling bidirectional activity-dependent regulation of the hyperpolarization activated current via PKA and calcineurin. PLoS One 2015; 10:e0117965. [PMID: 25692473 PMCID: PMC4333293 DOI: 10.1371/journal.pone.0117965] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/05/2015] [Indexed: 01/11/2023] Open
Abstract
Volume transmission results in phasic and tonic modulatory signals. The actions of tonic dopamine (DA) at type 1 DA receptors (D1Rs) are largely undefined. Here we show that tonic 5nM DA acts at D1Rs to stabilize neuronal output over minutes by enabling activity-dependent regulation of the hyperpolarization activated current (I h). In the presence but not absence of 5nM DA, I h maximal conductance (G max) was adjusted according to changes in slow wave activity in order to maintain spike timing. Our study on the lateral pyloric neuron (LP), which undergoes rhythmic oscillations in membrane potential with depolarized plateaus, demonstrated that incremental, bi-directional changes in plateau duration produced corresponding alterations in LP I hG max when preparations were superfused with saline containing 5nM DA. However, when preparations were superfused with saline alone there was no linear correlation between LP I hGmax and duty cycle. Thus, tonic nM DA modulated the capacity for activity to modulate LP I h G max; this exemplifies metamodulation (modulation of modulation). Pretreatment with the Ca2+-chelator, BAPTA, or the specific PKA inhibitor, PKI, prevented all changes in LP I h in 5nM DA. Calcineurin inhibitors blocked activity-dependent changes enabled by DA and revealed a PKA-mediated, activity-independent enhancement of LP I hG max. These data suggested that tonic 5nM DA produced two simultaneous, PKA-dependent effects: a direct increase in LP I h G max and a priming event that permitted calcineurin regulation of LP I h. The latter produced graded reductions in LP I hG max with increasing duty cycles. We also demonstrated that this metamodulation preserved the timing of LP’s first spike when network output was perturbed with bath-applied 4AP. In sum, 5nM DA permits slow wave activity to provide feedback that maintains spike timing, suggesting that one function of low-level, tonic modulation is to stabilize specific features of a dynamic output.
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Affiliation(s)
- Wulf-Dieter C. Krenz
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Edmund W. Rodgers
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Deborah J. Baro
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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19
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Pan Y, Laird JG, Yamaguchi DM, Baker SA. A di-arginine ER retention signal regulates trafficking of HCN1 channels from the early secretory pathway to the plasma membrane. Cell Mol Life Sci 2014; 72:833-43. [PMID: 25142030 PMCID: PMC4309907 DOI: 10.1007/s00018-014-1705-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/14/2014] [Accepted: 08/12/2014] [Indexed: 12/25/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels carry Ih, which contributes to neuronal excitability and signal transmission in the nervous system. Controlling the trafficking of HCN1 is an important aspect of its regulation, yet the details of this process are poorly understood. Here, we investigated how the C-terminus of HCN1 regulates trafficking by testing for its ability to redirect the localization of a non-targeted reporter in transgenic Xenopus laevis photoreceptors. We found that HCN1 contains an ER localization signal and through a series of deletion constructs, identified the responsible di-arginine ER retention signal. This signal is located in the intrinsically disordered region of the C-terminus of HCN1. To test the function of the ER retention signal in intact channels, we expressed wild type and mutant HCN1 in HEK293 cells and found this signal negatively regulates surface expression of HCN1. In summary, we report a new mode of regulating HCN1 trafficking: through the use of a di-arginine ER retention signal that monitors processing of the channel in the early secretory pathway.
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Affiliation(s)
- Yuan Pan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, 51 Newton Road, Biochemistry, 4-712 BSB, Iowa City, IA, 52242, USA
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20
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Abbott GW, Tai KK, Neverisky DL, Hansler A, Hu Z, Roepke TK, Lerner DJ, Chen Q, Liu L, Zupan B, Toth M, Haynes R, Huang X, Demirbas D, Buccafusca R, Gross SS, Kanda VA, Berry GT. KCNQ1, KCNE2, and Na+-coupled solute transporters form reciprocally regulating complexes that affect neuronal excitability. Sci Signal 2014; 7:ra22. [PMID: 24595108 DOI: 10.1126/scisignal.2005025] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Na(+)-coupled solute transport is crucial for the uptake of nutrients and metabolic precursors, such as myo-inositol, an important osmolyte and precursor for various cell signaling molecules. We found that various solute transporters and potassium channel subunits formed complexes and reciprocally regulated each other in vitro and in vivo. Global metabolite profiling revealed that mice lacking KCNE2, a K(+) channel β subunit, showed a reduction in myo-inositol concentration in cerebrospinal fluid (CSF) but not in serum. Increased behavioral responsiveness to stress and seizure susceptibility in Kcne2(-/-) mice were alleviated by injections of myo-inositol. Suspecting a defect in myo-inositol transport, we found that KCNE2 and KCNQ1, a voltage-gated potassium channel α subunit, colocalized and coimmunoprecipitated with SMIT1, a Na(+)-coupled myo-inositol transporter, in the choroid plexus epithelium. Heterologous coexpression demonstrated that myo-inositol transport by SMIT1 was augmented by coexpression of KCNQ1 but was inhibited by coexpression of both KCNQ1 and KCNE2, which form a constitutively active, heteromeric K(+) channel. SMIT1 and the related transporter SMIT2 were also inhibited by a constitutively active mutant form of KCNQ1. The activities of KCNQ1 and KCNQ1-KCNE2 were augmented by SMIT1 and the glucose transporter SGLT1 but were suppressed by SMIT2. Channel-transporter signaling complexes may be a widespread mechanism to facilitate solute transport and electrochemical crosstalk.
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Affiliation(s)
- Geoffrey W Abbott
- 1Bioelectricity Laboratory, Department of Pharmacology, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
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21
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Pan Y, Bhattarai S, Modestou M, Drack AV, Chetkovich DM, Baker SA. TRIP8b is required for maximal expression of HCN1 in the mouse retina. PLoS One 2014; 9:e85850. [PMID: 24409334 PMCID: PMC3883711 DOI: 10.1371/journal.pone.0085850] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/31/2013] [Indexed: 01/04/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are cation-selective channels present in retina, brain and heart. The activity of HCN channels contributes to signal integration, cell excitability and pacemaker activity. HCN1 channels expressed in photoreceptors participate in keeping light responses transient and are required for normal mesopic vision. The subcellular localization of HCN1 varies among cell types. In photoreceptors HCN1 is concentrated in the inner segments while in other retinal neurons, HCN1 is evenly distributed though the cell. This is in contrast to hippocampal neurons where HCN1 is concentrated in a subset of dendrites. A key regulator of HCN1 trafficking and activity is tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b). Multiple splice isoforms of TRIP8b are expressed throughout the brain and can differentially regulate the surface expression and activity of HCN1. The purpose of the present study was to determine which isoforms of TRIP8b are expressed in the retina and to test if loss of TRIP8b alters HCN1 expression or trafficking. We found that TRIP8b colocalizes with HCN1 in multiple retina neurons and all major splice isoforms of TRIP8b are expressed in the retina. Photoreceptors express three different isoforms. In TRIP8b knockout mice, the ability of HCN1 to traffic to the surface of retinal neurons is unaffected. However, there is a large decrease in the total amount of HCN1. We conclude that TRIP8b in the retina is needed to achieve maximal expression of HCN1.
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Affiliation(s)
- Yuan Pan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Sajag Bhattarai
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Modestos Modestou
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Dane M. Chetkovich
- The Ken & Ruth Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Sheila A. Baker
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Qiao GF, Qian Z, Sun HL, Xu WX, Yan ZY, Liu Y, Zhou JY, Zhang HC, Wang LJ, Pan XD, Fu Y. Remodeling of hyperpolarization-activated current, Ih, in Ah-type visceral ganglion neurons following ovariectomy in adult rats. PLoS One 2013; 8:e71184. [PMID: 23951107 PMCID: PMC3741359 DOI: 10.1371/journal.pone.0071184] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 06/27/2013] [Indexed: 12/21/2022] Open
Abstract
Hyperpolarization-activated currents (Ih) mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels modulate excitability of myelinated A− and Ah-type visceral ganglion neurons (VGN). Whether alterations in Ih underlie the previously reported reduction of excitability of myelinated Ah-type VGNs following ovariectomy (OVX) has remained unclear. Here we used the intact nodose ganglion preparation in conjunction with electrophysiological approaches to examine the role of Ih remodeling in altering Ah-type neuron excitability following ovariectomy in adult rats. Ah-type neurons were identified based on their afferent conduction velocity. Ah-type neurons in nodose ganglia from non-OVX rats exhibited a voltage ‘sag’ as well as ‘rebound’ action potentials immediately following hyperpolarizing current injections, which both were suppressed by the Ih blocker ZD7288. Repetitive spike activity induced afterhyperpolarizations lasting several hundreds of milliseconds (termed post-excitatory membrane hyperpolarizations, PEMHs), which were significantly reduced by ZD7288, suggesting that they resulted from transient deactivation of Ih during the preceding spike trains. Ovariectomy reduced whole-cell Ih density, caused a hyperpolarizing shift of the voltage-dependence of Ih activation, and slowed Ih activation. OVX-induced Ih remodeling was accompanied by a flattening of the stimulus frequency/response curve and loss of PEMHs. Also, HCN1 mRNA levels were reduced by ∼30% in nodose ganglia from OVX rats compared with their non-OVX counterparts. Acute exposure of nodose ganglia to 17beta-estradiol partly restored Ih density and accelerated Ih activation in Ah-type cells. In conclusion, Ih plays a significant role in modulating the excitability of myelinated Ah-type VGNs in adult female rats.
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Affiliation(s)
- Guo-Fen Qiao
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, Heilongjiang, China
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhao Qian
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Hong-Li Sun
- Department of Pharmacology, Da-Qing Campus of Harbin Medical University, Da-Qing, Heilongjiang, China
| | - Wen-Xiao Xu
- Department of Orthopedics, the First Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhen-Yu Yan
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yang Liu
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Jia-Ying Zhou
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Hao-Cheng Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Li-Juan Wang
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiao-Dong Pan
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yili Fu
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, Heilongjiang, China
- * E-mail:
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Abbott GW. KCNE genetics and pharmacogenomics in cardiac arrhythmias: much ado about nothing? Expert Rev Clin Pharmacol 2013; 6:49-60. [PMID: 23272793 PMCID: PMC4917007 DOI: 10.1586/ecp.12.76] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Voltage-gated ion channels respond to changes in membrane potential with conformational shifts that either facilitate or stem the movement of charged ions across the cell membrane. This controlled movement of ions is particularly important for the action potentials of excitable cells such as cardiac myocytes and therefore essential for timely beating of the heart. Inherited mutations in ion channel genes and in the genes encoding proteins that regulate them can cause lethal cardiac arrhythmias either by direct channel disruption or by altering interactions with therapeutic drugs, the best-understood example of both these scenarios being long QT syndrome (LQTS). Unsurprisingly, mutations in the genes encoding ion channel pore-forming α subunits underlie the large majority (~90%) of identified cases of inherited LQTS. Given that inherited LQTS is comparatively rare in itself (~0.04% of the US population), is pursuing study of the remaining known and unknown LQTS-associated genes subject to the law of diminishing returns? Here, with a particular focus on the KCNE family of single transmembrane domain K(+) channel ancillary subunits, the significance to cardiac pharmacogenetics of ion channel regulatory subunits is discussed.
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Affiliation(s)
- Geoffrey W Abbott
- Department of Pharmacology, Department of Physiology & Biophysics, University of California, Irvine, CA, USA.
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