1
|
Yang Y, Zheng C, Chen B, Hernandez NC, Faust PL, Cai Z, Louis ED, Matuskey D. Decreased Synaptic Vesicle Glycoprotein 2A Binding in the Human Postmortem Essential Tremor Cerebellum: Evidence of Reduction in Synaptic Density. CEREBELLUM (LONDON, ENGLAND) 2024; 23:1053-1060. [PMID: 37783917 DOI: 10.1007/s12311-023-01611-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/27/2023] [Indexed: 10/04/2023]
Abstract
OBJECTIVE Despite being one of the most prevalent neurological diseases, the pathophysiology of essential tremor (ET) is not fully understood. Neuropathological studies have identified numerous degenerative changes in the cerebellum of ET patients, however. These data align with considerable clinical and neurophysiological data linking ET to the cerebellum. While neuroimaging studies have variably shown mild atrophy in the cerebellum, marked atrophy is not a clear feature of the cerebellum in ET and a search for a more suitable neuroimaging signature of neurodegeneration is in order. Postmortem studies in ET have examined different neuropathological alterations in the cerebellum, but as of yet have not focused on measures of generalized synaptic markers. This pilot study focuses on synaptic vesicle glycoprotein 2A (SV2A), a protein expressed in practically all synapses in the brain, as a measure of synaptic density in postmortem ET cases. METHODS The current study utilized autoradiography with the SV2A radioligand [18F]SDM-16 to assess synaptic density in the cerebellar cortex and dentate nucleus in three ET cases and three age-matched controls. RESULTS Using [18F]SDM-16, SV2A was 53% and 46% lower in the cerebellar cortex and dentate nucleus, respectively, in ET cases compared to age-matched controls. CONCLUSION In this pilot study, using in vitro SV2A autoradiography, we have observed significantly lower synaptic density in the cerebellar cortex and dentate nucleus of ET cases. Future research could expand on our sample size and focus on in vivo imaging in ET to explore whether SV2A imaging could serve as a much-needed disease biomarker.
Collapse
Affiliation(s)
- Yanghong Yang
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Chao Zheng
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Baosheng Chen
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Nora C Hernandez
- Department of Neurology, University of Texas Southwestern School of Medicine, Dallas, TX, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons and the New York Presbyterian Hospital, New York, NY, USA
| | - Zhengxin Cai
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern School of Medicine, Dallas, TX, USA
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.
| |
Collapse
|
2
|
Martuscello RT, Sivaprakasam K, Hartstone W, Kuo SH, Konopka G, Louis ED, Faust PL. Gene Expression Analysis of Laser-Captured Purkinje Cells in the Essential Tremor Cerebellum. CEREBELLUM (LONDON, ENGLAND) 2023; 22:1166-1181. [PMID: 36242761 PMCID: PMC10359949 DOI: 10.1007/s12311-022-01483-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/28/2022] [Indexed: 12/13/2022]
Abstract
Essential tremor (ET) is a common, progressive neurological disease characterized by an 8-12-Hz kinetic tremor. Despite its high prevalence, the patho-mechanisms of tremor in ET are not fully known. Through comprehensive studies in postmortem brains, we identified major morphological changes in the ET cerebellum that reflect cellular damage in Purkinje cells (PCs), suggesting that PC damage is central to ET pathogenesis. We previously performed a transcriptome analysis in ET cerebellar cortex, identifying candidate genes and several dysregulated pathways. To directly target PCs, we purified RNA from PCs isolated by laser capture microdissection and performed the first ever PC-specific RNA-sequencing analysis in ET versus controls. Frozen postmortem cerebellar cortex from 24 ETs and 16 controls underwent laser capture microdissection, obtaining ≥2000 PCs per sample. RNA transcriptome was analyzed via differential gene expression, principal component analysis (PCA), and gene set enrichment analyses (GSEA). We identified 36 differentially expressed genes, encompassing multiple cellular processes. Some ET (13/24) had greater dysregulation of these genes and segregated from most controls and remaining ETs in PCA. Characterization of genes/pathways enriched in this PCA and GSEA identified multiple pathway dysregulations in ET, including RNA processing/splicing, synapse organization/ion transport, and oxidative stress/inflammation. Furthermore, a different set of pathways characterized marked heterogeneity among ET patients. Our data indicate a range of possible mechanisms for the pathogenesis of ET. Significant heterogeneity among ET combined with dysregulation of multiple cellular processes supports the notion that ET is a family of disorders rather than one disease entity.
Collapse
Affiliation(s)
- Regina T Martuscello
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, 10032, USA
| | - Karthigayini Sivaprakasam
- Peter O'Donnell Jr. Brain Institute, Department of Neuroscience, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA
| | - Whitney Hartstone
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, 10032, USA
| | - Sheng-Han Kuo
- Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University, 650 W 168th Street, BB302, New York, NY, USA
| | - Genevieve Konopka
- Peter O'Donnell Jr. Brain Institute, Department of Neuroscience, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Suite NL9.114, Dallas, TX, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, 10032, USA.
| |
Collapse
|
3
|
Yang Y, Zheng C, Chen B, Hernandez NC, Faust PL, Cai Z, Louis ED, Matuskey D. Decreased Synaptic Vesicle Glycoprotein 2A Binding in the Human Postmortem Essential Tremor Cerebellum: Evidence of Reduction in Synaptic Density. RESEARCH SQUARE 2023:rs.3.rs-2838184. [PMID: 37205584 PMCID: PMC10187382 DOI: 10.21203/rs.3.rs-2838184/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Objective Despite being one of the most prevalent neurological diseases, the pathophysiology of essential tremor (ET) is not fully understood. Neuropathological studies have identified numerous degenerative changes in the cerebellum of ET patients, however. These data align with considerable clinical and neurophysiological data linking ET to the cerebellum. While neuroimaging studies have variably shown mild atrophy in the cerebellum, marked atrophy is not a clear feature of the cerebellum in ET and that a search for a more suitable neuroimaging signature of neurodegeneration is in order. Postmortem studies in ET have examined different neuropathological alterations in the cerebellum, but as of yet have not focused on measures of generalized synaptic markers. This pilot study focuses on synaptic vesicle glycoprotein 2A (SV2A), a protein expressed in practically all synapses in the brain, as a measure of synaptic density in postmortem ET cases. Methods The current study utilized autoradiography with the SV2A radioligand [ 18 F]SDM-16 to assess synaptic density in the cerebellar cortex and dentate nucleus in three ET cases and three age-matched controls. Results Using [ 18 F]SDM-16, SV2A was 53% and 46% lower in the cerebellar cortex and dentate nucleus, respectively, in ET cases compared to age-matched controls. Conclusion For the first time, using in vitro SV2A autoradiography, we have observed significantly lower synaptic density in the cerebellar cortex and dentate nucleus of ET cases. Future research could focus on in vivo imaging in ET to explore whether SV2A imaging could serve as a much-needed disease biomarker.
Collapse
Affiliation(s)
| | | | | | | | - Phyllis L Faust
- Columbia University Vagelos College of Physicians and Surgeons and the New York Presbyterian Hospital
| | | | - Elan D Louis
- University of Texas Southwestern School of Medicine
| | | |
Collapse
|
4
|
Hu YY, Yang G, Liang XS, Ding XS, Xu DE, Li Z, Ma QH, Chen R, Sun YY. Transcranial low-intensity ultrasound stimulation for treating central nervous system disorders: A promising therapeutic application. Front Neurol 2023; 14:1117188. [PMID: 36970512 PMCID: PMC10030814 DOI: 10.3389/fneur.2023.1117188] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 02/10/2023] [Indexed: 03/29/2023] Open
Abstract
Transcranial ultrasound stimulation is a neurostimulation technique that has gradually attracted the attention of researchers, especially as a potential therapy for neurological disorders, because of its high spatial resolution, its good penetration depth, and its non-invasiveness. Ultrasound can be categorized as high-intensity and low-intensity based on the intensity of its acoustic wave. High-intensity ultrasound can be used for thermal ablation by taking advantage of its high-energy characteristics. Low-intensity ultrasound, which produces low energy, can be used as a means to regulate the nervous system. The present review describes the current status of research on low-intensity transcranial ultrasound stimulation (LITUS) in the treatment of neurological disorders, such as epilepsy, essential tremor, depression, Parkinson's disease (PD), and Alzheimer's disease (AD). This review summarizes preclinical and clinical studies using LITUS to treat the aforementioned neurological disorders and discusses their underlying mechanisms.
Collapse
Affiliation(s)
- Yun-Yun Hu
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Gang Yang
- Lab Center, Medical College of Soochow University, Suzhou, China
| | - Xue-Song Liang
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
- Second Clinical College, Dalian Medical University, Dalian, Liaoning, China
| | - Xuan-Si Ding
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - De-En Xu
- Wuxi No. 2 People's Hospital, Wuxi, Jiangsu, China
| | - Zhe Li
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Sleep Medicine Center, Suzhou Guangji Hospital, The Affiliated Guangji Hospital of Soochow University, Suzhou, China
| | - Quan-Hong Ma
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
- Quan-Hong Ma
| | - Rui Chen
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- *Correspondence: Rui Chen
| | - Yan-Yun Sun
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
- Yan-Yun Sun
| |
Collapse
|
5
|
Wagle Shukla A. Reduction of neuronal hyperexcitability with modulation of T-type calcium channel or SK channel in essential tremor. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:335-355. [PMID: 35750369 DOI: 10.1016/bs.irn.2022.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Essential tremor is one of the most prevalent movement disorders. Propranolol and primidone are the first-line pharmacological therapies. They provide symptomatic control in less than 50% of patients. Topiramate, alprazolam, clonazepam, gabapentin, and botulinum toxin injections are the next line of treatments. These medications lead to modest improvements and are therefore commonly used as add-on agents. Surgical therapies, including deep brain stimulation (DBS) surgery and focused ultrasound beam targeted to the thalamus, are considered for treating tremor refractory to medications and lead to greater than 75% improvements in tremor symptoms. However, DBS is a costly and an invasive procedure; some patients report tolerance to benefits. Focused ultrasound therapy leading to brain lesions is associated with a possibility for permanent clinical deficits. Therefore, research efforts to develop the next generation of oral medications with greater benefits and lesser adverse effects are warranted. There is considerable evidence that the increased functions of calcium channels (P/Q-type and T-type channels) and reduced functions of calcium-activated potassium channels (SK channels) located in the neuronal membranes lead to tremor oscillations. Consequently, many new pharmacological studies have targeted these channels to leverage better clinical outcomes. The current review will discuss the pathophysiology, the specific importance of these channels, and the early clinical experience of using compounds targeting these channels to treat essential tremor.
Collapse
Affiliation(s)
- Aparna Wagle Shukla
- Department of Neurology, Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.
| |
Collapse
|
6
|
Bellows S, Jimenez-Shahed J. Is essential tremor a disorder of GABA dysfunction? No. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:285-310. [PMID: 35750366 DOI: 10.1016/bs.irn.2022.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Although essential tremor is common, its underlying pathophysiology remains uncertain, and several hypotheses seek to explain the tremor mechanism. The GABA hypothesis states that disinhibition of deep cerebellar neurons due to reduced GABAergic input from Purkinje cells results in increased pacemaker activity, leading to rhythmic output to the thalamo-cortical circuit and resulting in tremor. However, some neuroimaging, spectroscopy, and pathology studies have not shown a clear or consistent GABA deficiency in essential tremor, and animal models have indicated that large reductions of Purkinje cell inhibition may improve tremor. Instead, tremor is increasingly attributable to dysfunction in oscillating networks, where altered (but not necessarily reduced) inhibitory signaling can result in tremor. Hypersynchrony of Purkinje cell activity may account for excessive oscillatory cerebellar output, with potential contributions along multiple sites of the olivocerebellar loop. Although older animal tremor models, such as harmaline tremor, have explored contributions from the inferior olivary body, increasing evidence has pointed to the role of aberrant climbing fiber synaptic organization in oscillatory cerebellar activity and tremor generation. New animal models such as hotfoot17j mice, which exhibit abnormal climbing fiber organization due to mutations in Grid2, have recapitulated many features of ET. Similar abnormal climbing fiber architecture and excessive cerebellar oscillations as measured by EEG have been found in humans with essential tremor. Further understanding of hypersynchrony and excessive oscillatory activity in ET phenotypes may lead to more targeted and effective treatment options.
Collapse
|
7
|
Louis ED, Faust PL. Essential Tremor Within the Broader Context of Other Forms of Cerebellar Degeneration. THE CEREBELLUM 2021; 19:879-896. [PMID: 32666285 DOI: 10.1007/s12311-020-01160-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Essential tremor (ET) has recently been reconceptualized by many as a degenerative disease of the cerebellum. Until now, though, there has been no attempt to frame it within the context of these diseases. Here, we compare the clinical and postmortem features of ET with other cerebellar degenerations, thereby placing it within the broader context of these diseases. Action tremor is the hallmark feature of ET. Although often underreported in the spinocerebellar ataxias (SCAs), action tremors occur, and it is noteworthy that in SCA12 and 15, they are highly prevalent, often severe, and can be the earliest disease manifestation, resulting in an initial diagnosis of ET in many cases. Intention tremor, sometimes referred to as "cerebellar tremor," is a common feature of ET and many SCAs. Other features of cerebellar dysfunction, gait ataxia and eye motion abnormalities, are seen to a mild degree in ET and more markedly in SCAs. Several SCAs (e.g., SCA5, 6, 14, and 15), like ET, follow a milder and more protracted disease course. In ET, numerous postmortem changes have been localized to the cerebellum and are largely confined to the cerebellar cortex, preserving the cerebellar nuclei. Purkinje cell loss is modest. Similarly, in SCA3, 12, and 15, Purkinje cell loss is limited, and in SCA12 and 15, there is preservation of cerebellar nuclei and relative sparing of other central nervous system regions. Both clinically and pathologically, there are numerous similarities and intersection points between ET and other disorders of cerebellar degeneration.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology and Therapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| |
Collapse
|
8
|
Kakei S, Manto M, Tanaka H, Mitoma H. Pathophysiology of Cerebellar Tremor: The Forward Model-Related Tremor and the Inferior Olive Oscillation-Related Tremor. Front Neurol 2021; 12:694653. [PMID: 34262527 PMCID: PMC8273235 DOI: 10.3389/fneur.2021.694653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/18/2021] [Indexed: 01/14/2023] Open
Abstract
Lesions in the Guillain-Mollaret (G-M) triangle frequently cause various types of tremors or tremor-like movements. Nevertheless, we know relatively little about their generation mechanisms. The deep cerebellar nuclei (DCN), which is a primary node of the triangle, has two main output paths: the primary excitatory path to the thalamus, the red nucleus (RN), and other brain stem nuclei, and the secondary inhibitory path to the inferior olive (IO). The inhibitory path contributes to the dentato-olivo-cerebellar loop (the short loop), while the excitatory path contributes to the cerebrocerebellar loop (the long loop). We propose a novel hypothesis: each loop contributes to physiologically distinct type of tremors or tremor-like movements. One type of irregular tremor-like movement is caused by a lesion in the cerebrocerebellar loop, which includes the primary path. A lesion in this loop affects the cerebellar forward model and deteriorates its accuracy of prediction and compensation of the feedback delay, resulting in irregular instability of voluntary motor control, i.e., cerebellar ataxia (CA). Therefore, this type of tremor, such as kinetic tremor, is usually associated with other symptoms of CA such as dysmetria. We call this type of tremor forward model-related tremor. The second type of regular tremor appears to be correlated with synchronized oscillation of IO neurons due, at least in animal models, to reduced degrees of freedom in IO activities. The regular burst activity of IO neurons is precisely transmitted along the cerebellocerebral path to the motor cortex before inducing rhythmical reciprocal activities of agonists and antagonists, i.e., tremor. We call this type of tremor IO-oscillation-related tremor. Although this type of regular tremor does not necessarily accompany ataxia, the aberrant IO activities (i.e., aberrant CS activities) may induce secondary maladaptation of cerebellar forward models through aberrant patterns of long-term depression (LTD) and/or long-term potentiation (LTP) of the cerebellar circuitry. Although our hypothesis does not cover all tremors or tremor-like movement disorders, our approach integrates the latest theories of cerebellar physiology and provides explanations how various lesions in or around the G-M triangle results in tremors or tremor-like movements. We propose that tremor results from errors in predictions carried out by the cerebellar circuitry.
Collapse
Affiliation(s)
- Shinji Kakei
- Department of Anatomy and Physiology, Jissen Women's University, Tokyo, Japan
| | - Mario Manto
- Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, Charleroi, Belgium
- Service des Neurosciences, University of Mons, Mons, Belgium
| | - Hirokazu Tanaka
- Faculty of Information Technology, Tokyo City University, Tokyo, Japan
| | - Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo, Japan
| |
Collapse
|
9
|
Akman Ö, Utkan T, Arıcıoğlu F, Güllü K, Ateş N, Karson A. Agmatine has beneficial effect on harmaline-induced essential tremor in rat. Neurosci Lett 2021; 753:135881. [PMID: 33838255 DOI: 10.1016/j.neulet.2021.135881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/28/2021] [Accepted: 04/01/2021] [Indexed: 10/21/2022]
Abstract
Essential tremor (ET) is one of the most prevalent movement disorders and the most common cause of abnormal tremors. However, it cannot be treated efficiently with the currently available pharmacotherapy options. The pathophysiology of harmaline-induced tremor, most commonly used model of ET, involves various neurotransmitter systems including glutamate as well as ion channels. Agmatine, an endogenous neuromodulator, interacts with various glutamate receptor subtypes and ion channels, which have been associated with its' beneficial effects on several neurological disorders. The current study aims to assess the effect of agmatine on the harmaline model of ET. Two separate groups of male rats were injected either with saline or agmatine (40 mg/kg) 30 min prior to single intraperitoneal injection of harmaline (20 mg/kg). The percent duration, intensity and frequency of tremor and locomotor activity were evaluated by a custom-built tremor and locomotion analysis system. Pretreatment with agmatine reduced the percent tremor duration and intensity of tremor induced by harmaline, without affecting the tremor frequency. However, it did not affect the decreased spontaneous locomotor activity due to harmaline. This pattern of ameliorating effects of agmatine on harmaline-induced tremor provide the first evidence for being considered as a treatment option for ET.
Collapse
Affiliation(s)
- Özlem Akman
- Department of Physiology, Faculty of Medicine, Demiroglu Bilim University, Istanbul, Turkey.
| | - Tijen Utkan
- Kocaeli University, Faculty of Medicine, Department of Pharmacology, Kocaeli, Turkey.
| | - Feyza Arıcıoğlu
- Marmara University, Faculty of Pharmacy, Department of Pharmacology and Psychopharmacology Research Unit, Istanbul, Turkey.
| | - Kemal Güllü
- Department of Electrical and Electronics Engineering, İzmir Bakircay University, İzmir, Turkey.
| | - Nurbay Ateş
- Kocaeli University, Faculty of Medicine, Department of Physiology, Kocaeli, Turkey.
| | - Ayşe Karson
- Kocaeli University, Faculty of Medicine, Department of Physiology, Kocaeli, Turkey.
| |
Collapse
|
10
|
Objective detection of microtremors in netrin-G2 knockout mice. J Neurosci Methods 2021; 351:109074. [PMID: 33450333 DOI: 10.1016/j.jneumeth.2021.109074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND Essential tremor is the most prevalent movement disorder and is thought to be caused by abnormalities in the cerebellar system; however, its underlying neural mechanism is poorly understood. In this study, we found that mice lacking netrin-G2, a cell adhesion molecule which is expressed in neural circuits related to the cerebellar system, exhibited a microtremor resembling an essential tremor. However, it was difficult to quantify microtremors in netrin-G2 KO mice. NEW METHOD We developed a new tremor detector which can quantify the intensity and frequency of a tremor. RESULTS Using this system, we were able to characterize both the microtremors in netrin-G2 KO mice and low-dose harmaline-induced tremors which, to date, had been difficult to detect. Alcohol and anti-tremor drugs, which are effective in decreasing the symptoms of essential tremor in patients, were examined in netrin-G2 KO mice. We found that some drugs lowered the tremor frequency, but had little effect on tremor intensity. Forced swim as a stress stimulus in netrin-G2 KO mice dramatically enhanced tremor symptoms. COMPARISON WITH EXISTING METHODS The detection performance even for tremors induced by low-dose harmaline was similar to that in previous studies or more sensitive than the others. CONCLUSIONS Microtremors in netrin-G2 KO mice are reliably and quantitatively detected by our new tremor detection system. We found different effects of medicines and factors between human essential tremors and microtremors in netrin-G2 KO mice, suggesting that the causations, mechanisms, and symptoms of tremors vary and are heterogeneous, and the objective analyses are required.
Collapse
|
11
|
Handforth A, Lang EJ. Increased Purkinje Cell Complex Spike and Deep Cerebellar Nucleus Synchrony as a Potential Basis for Syndromic Essential Tremor. A Review and Synthesis of the Literature. THE CEREBELLUM 2020; 20:266-281. [PMID: 33048308 DOI: 10.1007/s12311-020-01197-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 12/19/2022]
Abstract
We review advances in understanding Purkinje cell (PC) complex spike (CS) physiology that suggest increased CS synchrony underlies syndromic essential tremor (ET). We searched PubMed for papers describing factors that affect CS synchrony or cerebellar circuits potentially related to tremor. Inferior olivary (IO) neurons are electrically coupled, with the degree of coupling controlled by excitatory and GABAergic inputs. Clusters of coupled IO neurons synchronize CSs within parasagittal bands via climbing fibers (Cfs). When motor cortex is stimulated in rats at varying frequencies, whisker movement occurs at ~10 Hz, correlated with synchronous CSs, indicating that the IO/CS oscillatory rhythm gates movement frequency. Intra-IO injection of the GABAA receptor antagonist picrotoxin increases CS synchrony, increases whisker movement amplitude, and induces tremor. Harmaline and 5-HT2a receptor activation also increase IO coupling and CS synchrony and induce tremor. The hotfoot17 mouse displays features found in ET brains, including cerebellar GluRδ2 deficiency and abnormal PC Cf innervation, with IO- and PC-dependent cerebellar oscillations and tremor likely due to enhanced CS synchrony. Heightened coupling within the IO oscillator leads, through its dynamic control of CS synchrony, to increased movement amplitude and, when sufficiently intense, action tremor. Increased CS synchrony secondary to aberrant Cf innervation of multiple PCs likely also underlies hotfoot17 tremor. Deep cerebellar nucleus (DCN) hypersynchrony may occur secondary to increased CS synchrony but might also occur from PC axonal terminal sprouting during partial PC loss. Through these combined mechanisms, increased CS/DCN synchrony may plausibly underlie syndromic ET.
Collapse
Affiliation(s)
- Adrian Handforth
- Neurology Service, Veterans Affairs Greater Los Angeles Healthcare System, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA.
| | - Eric J Lang
- Department of Neuroscience and Physiology, New York University, School of Medicine, New York, NY, USA
| |
Collapse
|
12
|
Nietz A, Krook-Magnuson C, Gutierrez H, Klein J, Sauve C, Hoff I, Christenson Wick Z, Krook-Magnuson E. Selective loss of the GABA Aα1 subunit from Purkinje cells is sufficient to induce a tremor phenotype. J Neurophysiol 2020; 124:1183-1197. [PMID: 32902350 DOI: 10.1152/jn.00100.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Previously, an essential tremor-like phenotype has been noted in animals with a global knockout of the GABAAα1 subunit. Given the hypothesized role of the cerebellum in tremor, including essential tremor, we used transgenic mice to selectively knock out the GABAAα1 subunit from cerebellar Purkinje cells. We examined the resulting phenotype regarding impacts on inhibitory postsynaptic currents, survival rates, gross motor abilities, and expression of tremor. Purkinje cell specific knockout of the GABAAα1 subunit abolished all GABAA-mediated inhibition in Purkinje cells, while leaving GABAA-mediated inhibition to cerebellar molecular layer interneurons intact. Selective loss of GABAAα1 from Purkinje cells did not produce deficits on the accelerating rotarod, nor did it result in decreased survival rates. However, a tremor phenotype was apparent, regardless of sex or background strain. This tremor mimicked the tremor seen in animals with a global knockout of the GABAAα1 subunit, and, like essential tremor in patients, was responsive to ethanol. These findings indicate that reduced inhibition to Purkinje cells is sufficient to induce a tremor phenotype, highlighting the importance of the cerebellum, inhibition, and Purkinje cells in tremor.NEW & NOTEWORTHY Animals with a global knockout of the GABAAα1 subunit show a tremor phenotype reminiscent of essential tremor. Here we show that selective knockout of GABAAα1 from Purkinje cells is sufficient to produce a tremor phenotype, although this tremor is less severe than seen in animals with a global knockout. These findings illustrate that the cerebellum can play a key role in the genesis of the observed tremor phenotype.
Collapse
Affiliation(s)
- Angela Nietz
- University of Minnesota, Department of Neuroscience, Minneapolis, Minnesota
| | | | - Haruna Gutierrez
- University of Minnesota, Department of Neuroscience, Minneapolis, Minnesota
| | - Julia Klein
- University of Minnesota, Department of Neuroscience, Minneapolis, Minnesota
| | - Clarke Sauve
- University of Minnesota, Department of Neuroscience, Minneapolis, Minnesota
| | - Isaac Hoff
- University of Minnesota, Department of Neuroscience, Minneapolis, Minnesota
| | | | | |
Collapse
|
13
|
Louis ED, Faust PL. Essential tremor: the most common form of cerebellar degeneration? CEREBELLUM & ATAXIAS 2020; 7:12. [PMID: 32922824 PMCID: PMC7427947 DOI: 10.1186/s40673-020-00121-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/03/2020] [Indexed: 02/07/2023]
Abstract
Background The degenerative cerebellar ataxias comprise a large and heterogeneous group of neurological diseases whose hallmark clinical feature is ataxia, and which are accompanied, to variable degrees, by other features that are attributable to cerebellar dysfunction. Essential tremor (ET) is an exceptionally common neurological disease whose primary motor feature is action tremor, although patients often manifest intention tremor, mild gait ataxia and several other features of cerebellar dysfunction. Main Body In this paper, we review the abundant evidence derived from clinical, neuroimaging and postmortem studies, linking ET to cerebellar dysfunction. Furthermore, we review the combination of clinical, natural history and postmortem features suggesting that ET is neurodegenerative. We then compare the prevalence of ET (400 – 900 cases per 100,000) to that of the other cerebellar degenerations (ranging from <0.5 – 9 cases per 100,000, and in composite likely to be on the order of 20 cases per 100,000) and conclude that ET is 20 to 45 times more prevalent than all other forms of cerebellar degeneration combined. Conclusion Given the data we present, it is logical to conclude that ET is, by far, the most common form of cerebellar degeneration.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology and Therapeutics, University of Texas Southwestern, Dallas, TX USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY USA
| |
Collapse
|
14
|
Sengul Y, Bal N, Louis ED. Evidence of central involvement in essential tremor: a detailed study of auditory pathway physiology. J Neural Transm (Vienna) 2020; 127:1153-1159. [PMID: 32507996 DOI: 10.1007/s00702-020-02215-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 05/28/2020] [Indexed: 10/24/2022]
Abstract
Essential tremor (ET) is a common tremor disorder that is likely neurodegenerative. The pathophysiology of ET involves the cerebellum and its connections in the brainstem and thalamus. Hearing dysfunction has been shown to be a non-motor finding in ET patients. A limited number of studies have suggested that cochlear pathology is the cause, but studies have not evaluated the integrity of the primary auditory pathway in ET. The main aim of this study is to investigate the integrity of the auditory pathway via auditory brainstem response (ABR) and auditory middle latency response (AMLR), thereby allowing us to evaluate the auditory pathway from the 8th cranial nerve to the cerebral cortex. Sixteen ET patients and sixteen age- and gender-matched controls (64 ears) were evaluated. In the ABR study, we detected prolongation of wave V peak latencies (ms) in ET (p = 0.02). In the AMLR study, P0 (p = 0.03), Pa (p = 0.008), Na (p = 0.03), and Nb (p = 0.01) waves differed between the two groups. Eleven ET patients and four control subjects had abnormal electrophysiological findings (ABR or AMLR or both) (68.8% vs. 25%, p = 0.01). Tremor duration was greater in ET patients with abnormal electrophysiological findings (p = 0.01). Finally, we observed prolongation of latencies after the ABR III wave, indicating that abnormalities exist within the superior olivary complex. For the first time, our research provides evidence that ET-related pathology is present at the subcortical and cortical levels of the auditory pathway.
Collapse
Affiliation(s)
- Yildizhan Sengul
- Department of Neurology, Faculty of Medicine, Bezmialem Foundation University, Fatih, Istanbul, Turkey. .,Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.
| | - Nilufer Bal
- Department of Audiology, Faculty of Medical Sciences, Bezmialem Foundation University, Fatih, Istanbul, Turkey
| | - Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
| |
Collapse
|
15
|
Brown AM, White JJ, van der Heijden ME, Zhou J, Lin T, Sillitoe RV. Purkinje cell misfiring generates high-amplitude action tremors that are corrected by cerebellar deep brain stimulation. eLife 2020; 9:e51928. [PMID: 32180549 PMCID: PMC7077982 DOI: 10.7554/elife.51928] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
Tremor is currently ranked as the most common movement disorder. The brain regions and neural signals that initiate the debilitating shakiness of different body parts remain unclear. Here, we found that genetically silencing cerebellar Purkinje cell output blocked tremor in mice that were given the tremorgenic drug harmaline. We show in awake behaving mice that the onset of tremor is coincident with rhythmic Purkinje cell firing, which alters the activity of their target cerebellar nuclei cells. We mimic the tremorgenic action of the drug with optogenetics and present evidence that highly patterned Purkinje cell activity drives a powerful tremor in otherwise normal mice. Modulating the altered activity with deep brain stimulation directed to the Purkinje cell output in the cerebellar nuclei reduced tremor in freely moving mice. Together, the data implicate Purkinje cell connectivity as a neural substrate for tremor and a gateway for signals that mediate the disease.
Collapse
Affiliation(s)
- Amanda M Brown
- Department of Pathology and Immunology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute of Texas Children's HospitalHoustonUnited States
| | - Joshua J White
- Department of Pathology and Immunology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute of Texas Children's HospitalHoustonUnited States
| | - Meike E van der Heijden
- Department of Pathology and Immunology, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute of Texas Children's HospitalHoustonUnited States
| | - Joy Zhou
- Department of Pathology and Immunology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute of Texas Children's HospitalHoustonUnited States
| | - Tao Lin
- Department of Pathology and Immunology, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute of Texas Children's HospitalHoustonUnited States
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute of Texas Children's HospitalHoustonUnited States
- Development, Disease Models & Therapeutics Graduate Program, Baylor College of MedicineHoustonUnited States
| |
Collapse
|
16
|
Samuelsson JG, Sundaram P, Khan S, Sereno MI, Hämäläinen MS. Detectability of cerebellar activity with magnetoencephalography and electroencephalography. Hum Brain Mapp 2020; 41:2357-2372. [PMID: 32115870 PMCID: PMC7244390 DOI: 10.1002/hbm.24951] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/15/2019] [Accepted: 02/01/2020] [Indexed: 12/31/2022] Open
Abstract
Electrophysiological signals from the cerebellum have traditionally been viewed as inaccessible to magnetoencephalography (MEG) and electroencephalography (EEG). Here, we challenge this position by investigating the ability of MEG and EEG to detect cerebellar activity using a model that employs a high‐resolution tessellation of the cerebellar cortex. The tessellation was constructed from repetitive high‐field (9.4T) structural magnetic resonance imaging (MRI) of an ex vivo human cerebellum. A boundary‐element forward model was then used to simulate the M/EEG signals resulting from neural activity in the cerebellar cortex. Despite significant signal cancelation due to the highly convoluted cerebellar cortex, we found that the cerebellar signal was on average only 30–60% weaker than the cortical signal. We also made detailed M/EEG sensitivity maps and found that MEG and EEG have highly complementary sensitivity distributions over the cerebellar cortex. Based on previous fMRI studies combined with our M/EEG sensitivity maps, we discuss experimental paradigms that are likely to offer high M/EEG sensitivity to cerebellar activity. Taken together, these results show that cerebellar activity should be clearly detectable by current M/EEG systems with an appropriate experimental setup.
Collapse
Affiliation(s)
- John G Samuelsson
- Harvard-MIT Division of Health Sciences and Technology (HST), Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Padmavathi Sundaram
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Sheraz Khan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Martin I Sereno
- Department of Psychology and Neuroimaging Center, San Diego State University, San Diego, California, USA.,Experimental Psychology, University College London, London, UK
| | - Matti S Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
17
|
Essential tremor pathology: neurodegeneration and reorganization of neuronal connections. Nat Rev Neurol 2020; 16:69-83. [PMID: 31959938 DOI: 10.1038/s41582-019-0302-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2019] [Indexed: 01/26/2023]
Abstract
Essential tremor (ET) is the most common tremor disorder globally and is characterized by kinetic tremor of the upper limbs, although other clinical features can also occur. Postmortem studies are a particularly important avenue for advancing our understanding of the pathogenesis of ET; however, until recently, the number of such studies has been limited. Several recent postmortem studies have made important contributions to our understanding of the pathological changes that take place in ET. These studies identified abnormalities in the cerebellum, which primarily affected Purkinje cells (PCs), basket cells and climbing fibres, in individuals with ET. We suggest that some of these pathological changes (for example, focal PC axonal swellings, swellings in and regression of the PC dendritic arbor and PC death) are likely to be primary and degenerative. By contrast, other changes, such as an increase in PC recurrent axonal collateral formation and hypertrophy of GABAergic basket cell axonal processes, could be compensatory responses to restore cerebellar GABAergic tone and cerebellar cortical inhibitory efficacy. Such compensatory responses are likely to be insufficient, enabling the disease to progress. Here, we review the results of recent postmortem studies of ET and attempt to place these findings into an anatomical-physiological disease model.
Collapse
|
18
|
Kuo SH, Louis ED, Faust PL, Handforth A, Chang SY, Avlar B, Lang EJ, Pan MK, Miterko LN, Brown AM, Sillitoe RV, Anderson CJ, Pulst SM, Gallagher MJ, Lyman KA, Chetkovich DM, Clark LN, Tio M, Tan EK, Elble RJ. Current Opinions and Consensus for Studying Tremor in Animal Models. CEREBELLUM (LONDON, ENGLAND) 2019; 18:1036-1063. [PMID: 31124049 PMCID: PMC6872927 DOI: 10.1007/s12311-019-01037-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tremor is the most common movement disorder; however, we are just beginning to understand the brain circuitry that generates tremor. Various neuroimaging, neuropathological, and physiological studies in human tremor disorders have been performed to further our knowledge of tremor. But, the causal relationship between these observations and tremor is usually difficult to establish and detailed mechanisms are not sufficiently studied. To overcome these obstacles, animal models can provide an important means to look into human tremor disorders. In this manuscript, we will discuss the use of different species of animals (mice, rats, fruit flies, pigs, and monkeys) to model human tremor disorders. Several ways to manipulate the brain circuitry and physiology in these animal models (pharmacology, genetics, and lesioning) will also be discussed. Finally, we will discuss how these animal models can help us to gain knowledge of the pathophysiology of human tremor disorders, which could serve as a platform towards developing novel therapies for tremor.
Collapse
Affiliation(s)
- Sheng-Han Kuo
- Department of Neurology, Columbia University, 650 West 168th Street, Room 305, New York, NY, 10032, USA.
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, 800 Howard Avenue, Ste Lower Level, New Haven, CT, 06519, USA.
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA.
- Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Adrian Handforth
- Neurology Service, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Su-Youne Chang
- Department of Neurologic Surgery and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Billur Avlar
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Eric J Lang
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Ming-Kai Pan
- Department of Medical Research and Neurology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Lauren N Miterko
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA
| | - Amanda M Brown
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Collin J Anderson
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | | | - Kyle A Lyman
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Lorraine N Clark
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Murni Tio
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL, USA
| |
Collapse
|
19
|
Martuscello RT, Kerridge CA, Chatterjee D, Hartstone WG, Kuo SH, Sims PA, Louis ED, Faust PL. Gene expression analysis of the cerebellar cortex in essential tremor. Neurosci Lett 2019; 721:134540. [PMID: 31707044 DOI: 10.1016/j.neulet.2019.134540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/28/2019] [Accepted: 10/08/2019] [Indexed: 02/06/2023]
Abstract
Essential tremor (ET) is one of the most common neurological diseases, with a central feature of an 8-12 Hz kinetic tremor. While previous postmortem studies have identified a cluster of morphological changes in the ET cerebellum centered in/around the Purkinje cell (PC) population, including a loss of PCs in some studies, the underlying molecular mechanisms for these changes are not clear. As genomic studies of ET patients have yet to identify major genetic contributors and animal models that fully recapitulate the human disease do not yet exist, the study of human tissue is currently the most applicable method to gain a mechanistic insight into ET disease pathogenesis. To begin exploration of an underlying molecular source of ET disease pathogenesis, we have performed the first transcriptomic analysis by direct sequencing of RNA from frozen cerebellar cortex tissue in 33 ET patients compared to 21 normal controls. Principal component analysis showed a heterogenous distribution of the expression data in ET patients that only partially overlapped with control patients. Differential expression analysis identified 231 differentially expressed gene transcripts ('top gene hits'), a subset of which has defined expression profiles in the cerebellum across neuronal and glial cell types but a largely unknown relationship to cerebellar function and/or ET pathogenesis. Gene set enrichment analysis (GSEA) identified dysregulated pathways of interest and stratified dysregulation among ET cases. By GSEA and mining curated databases, we compiled major categories of dysregulated processes and clustered string networks of known interacting proteins. Here we demonstrate that these 'top gene hits' contribute to regulation of four main biological processes, which are 1) axon guidance, 2) microtubule motor activity, 3) endoplasmic reticulum (ER) to Golgi transport and 4) calcium signaling/synaptic transmission. The results of our transcriptomic analysis suggest there is a range of different processes involved among ET cases, and draws attention to a particular set of genes and regulatory pathways that provide an initial platform to further explore the underlying biology of ET.
Collapse
Affiliation(s)
- Regina T Martuscello
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, USA; College of Physicians and Surgeons, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, New York, NY, USA.
| | - Chloë A Kerridge
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, USA; College of Physicians and Surgeons, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, New York, NY, USA.
| | - Debotri Chatterjee
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, USA; College of Physicians and Surgeons, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, New York, NY, USA.
| | - Whitney G Hartstone
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, USA; College of Physicians and Surgeons, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, New York, NY, USA.
| | - Sheng-Han Kuo
- College of Physicians and Surgeons, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, New York, NY, USA; Department of Neurology, College of Physicians and Surgeons, Columbia University, 630 W 168th Street, BB302, New York, NY, USA.
| | - Peter A Sims
- Department of Neurology, College of Physicians and Surgeons, Columbia University, 630 W 168th Street, BB302, New York, NY, USA; Department of Systems Biology, Columbia University Medical Center, 3960 Broadway, RM208, New York, NY, USA; Sulzberger Columbia Genome Center, Columbia University Medical Center, 1150 St. Nicholas Ave., New York, NY, USA; Department of Biochemistry & Molecular Biophysics, Columbia University Medical Center, 701 W 168th Street, New York, NY, USA.
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, 15 York Street, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, 15 York Street, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, 15 York Street, New Haven, CT, USA.
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, P&S 15-405, New York, NY, USA; College of Physicians and Surgeons, Columbia University Medical Center and the New York Presbyterian Hospital, 630 W 168th Street, New York, NY, USA.
| |
Collapse
|
20
|
Abstract
Click here to listen to the Podcast Essential tremor is the most common form of tremor in humans. Given neurologists' high exposure to this condition, and its seemingly straightforward phenotype, it might seem easy to diagnose. However, 30%-50 % of patients labelled as having 'essential tremor' have other diagnoses, mostly Parkinson's disease and dystonia. The tremor of essential tremor is neither non-descript nor featureless but is multifaceted and highly patterned. This review focuses on its clinical features, beginning with a discussion of tremors and then briefly discussing its additional motor features, and presents several aids to help distinguish essential tremor from Parkinson's disease and dystonia. Careful attention to certain clinical nuances will aid the diagnosis and care of patients with essential tremor.
Collapse
Affiliation(s)
- Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA .,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
| |
Collapse
|
21
|
Sharabi S, Daniels D, Last D, Guez D, Zivli Z, Castel D, Levy Y, Volovick A, Grinfeld J, Rachmilevich I, Amar T, Mardor Y, Harnof S. Non-thermal focused ultrasound induced reversible reduction of essential tremor in a rat model. Brain Stimul 2019; 12:1-8. [DOI: 10.1016/j.brs.2018.08.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 08/12/2018] [Accepted: 08/22/2018] [Indexed: 12/18/2022] Open
|
22
|
Pan MK, Ni CL, Wu YC, Li YS, Kuo SH. Animal Models of Tremor: Relevance to Human Tremor Disorders. Tremor Other Hyperkinet Mov (N Y) 2018; 8:587. [PMID: 30402338 PMCID: PMC6214818 DOI: 10.7916/d89s37mv] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/10/2018] [Indexed: 12/17/2022] Open
Abstract
Background Tremor is the most common movement disorder; however, the pathophysiology of tremor remains elusive. While several neuropathological alterations in tremor disorders have been observed in post-mortem studies of human brains, a full understanding of the relationship between brain circuitry alterations and tremor requires testing in animal models. Additionally, tremor animal models are critical for our understanding of tremor pathophysiology, and/or to serve as a platform for therapy development. Methods A PubMed search was conducted in May 2018 to identify published papers for review. Results The methodology used in most studies on animal models of tremor lacks standardized measurement of tremor frequency and amplitude; instead, these studies are based on the visual inspection of phenotypes, which may fail to delineate tremor from other movement disorders such as ataxia. Of the animal models with extensive tremor characterization, harmaline-induced rodent tremor models provide an important framework showing that rhythmic and synchronous neuronal activities within the olivocerebellar circuit can drive action tremor. In addition, dopamine-depleted monkey and mouse models may develop rest tremor, highlighting the role of dopamine in rest tremor generation. Finally, other animal models of tremor have involvement of the cerebellar circuitry, leading to altered Purkinje cell physiology. Discussion Both the cerebellum and the basal ganglia are likely to play a role in tremor generation. While the cerebellar circuitry can generate rhythmic movements, the nigrostriatal system is likely to modulate the tremor circuit. Tremor disorders are heterogeneous in nature. Therefore, each animal model may represent a subset of tremor disorders, which collectively can advance our understanding of tremor.
Collapse
Affiliation(s)
- Ming-Kai Pan
- Department of Medical Research, National Taiwan University, Taipei, TW
| | - Chun-Lun Ni
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Yeuh-Chi Wu
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Yong-Shi Li
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| |
Collapse
|
23
|
Kunisawa N, Shimizu S, Kato M, Iha HA, Iwai C, Hashimura M, Ogawa M, Kawaji S, Kawakita K, Abe K, Ohno Y. Pharmacological characterization of nicotine-induced tremor: Responses to anti-tremor and anti-epileptic agents. J Pharmacol Sci 2018; 137:162-169. [PMID: 29945769 DOI: 10.1016/j.jphs.2018.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/18/2018] [Accepted: 05/23/2018] [Indexed: 12/19/2022] Open
Abstract
We previously showed that nicotine evoked kinetic tremor by activating the inferior olive, which is implicated in the pathogenesis of essential tremor, via α7 nicotinic acetylcholine receptors. Here, we evaluated the effects of various anti-tremor and anti-epileptic agents on nicotine-induced tremor in mice to clarify the pharmacological characteristics of nicotine tremor. Drugs effective for essential tremor, propranolol, diazepam and phenobarbital, all significantly inhibited kinetic tremor induced by an intraperitoneal (i.p.) injection of nicotine (1 mg/kg). In contrast, none of the medications for Parkinson's disease, l-DOPA, bromocriptine or trihexyphenidyl, affected the nicotine tremor. Among the anti-epileptic agents examined, valproate, carbamazepine and ethosuximide, significantly inhibited nicotine-induced tremor. In addition, a selective T-type Ca2+ channel blocker, TTA-A2, also suppressed the nicotine tremor. However, neither gabapentin, topiramate, zonisamide nor levetiracetam significantly affected nicotine-induced tremor. The present results show that nicotine-induced tremor resembles essential tremor not only on the neural basis, but also in terms of the pharmacological responses to anti-tremor agents, implying that nicotine-induced tremor can serve as a model for essential tremor. In addition, it is suggested that anti-epileptic agents, which have stimulant actions on the GABAergic system or blocking actions on voltage-gated Na+ channels and T-type Ca2+ channels, can alleviate essential tremor.
Collapse
Affiliation(s)
- Naofumi Kunisawa
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Saki Shimizu
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Masaki Kato
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Higor A Iha
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Chihiro Iwai
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Mai Hashimura
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Mizuki Ogawa
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Shohei Kawaji
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Kazuma Kawakita
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Keisuke Abe
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
| |
Collapse
|
24
|
Abstract
Tremor is clinically defined as a rhythmic, oscillating movement of parts of the body, which functionally leads to impairment of the coordination and execution of targeted movements. It can be a symptom of a primary disease, such as resting tremor in Parkinson's disease or occur as an independent disease, such as essential or orthostatic tremor. For the development of tremor, cerebral components as well as mechanisms at the spinal and muscular level play an important role. This review presents the results of new imaging and electrophysiological studies that have led to important advances in our understanding of the pathophysiology of tremor. We discuss pathophysiological models for the development of resting tremor in Parkinson's disease, essential and orthostatic tremor. We describe recent developments starting from the classical generator model, with an onset of pathological oscillations in distinct cerebral regions, to a network perspective in which tremor arises and spreads through existing anatomical or newly emerged pathological brain networks. In particular translational approaches are presented and discussed. These could serve in the future as a basis for the development of new therapeutic strategies.
Collapse
Affiliation(s)
- M Muthuraman
- Sektion für Bewegungsstörungen und Neurostimulation, Biomedizinische Statistik und multimodale Signalverarbeitung, Klinik und Poliklinik für Neurologie, Johannes Gutenberg-Universität Mainz, Langenbeckstr. 1, 55131, Mainz, Deutschland
| | - A Schnitzler
- Klinik für Neurologie, Universitätsklinik Düsseldorf, Heinrich-Heine-Universität, Düsseldorf, Deutschland
| | - S Groppa
- Sektion für Bewegungsstörungen und Neurostimulation, Biomedizinische Statistik und multimodale Signalverarbeitung, Klinik und Poliklinik für Neurologie, Johannes Gutenberg-Universität Mainz, Langenbeckstr. 1, 55131, Mainz, Deutschland.
| |
Collapse
|
25
|
Schaefer SM, Vives Rodriguez A, Louis ED. Brain circuits and neurochemical systems in essential tremor: insights into current and future pharmacotherapeutic approaches. Expert Rev Neurother 2017; 18:101-110. [PMID: 29206482 DOI: 10.1080/14737175.2018.1413353] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION There are few medications that are available for the treatment of essential tremor (ET) and they are only moderately effective. Areas covered: Data were obtained from a PubMed search. Original articles, review articles, and clinical guidelines were included. Two disease models for ET have been proposed: 1) the olivary model, which attributes ET to a pathological pacemaker in the inferior olivary nucleus, and 2) the cerebellar degeneration model, which postulates that ET originates in the cerebellum and could be related to deficient or abnormal Purkinje cell (PC) output. Underlying biochemical dysfunction in T-type calcium channels (T-tCaC) may loosely be linked to the first model and deficiency/abnormality in γ-aminobutyric acid (GABA) neurotransmission, to the second. Expert commentary: Human data points robustly to the role of GABA in ET. Numerous medications that target the GABA system have been tried, with variable success. Given the many different types of GABA-ergic neurons, and the multitude of GABAA receptor subtypes, a given medication could have competing/cancelling effects. It would seem that influencing GABA receptors broadly is not as effective as targeting certain GABAA receptor subtypes. Future research should seek to identify molecular candidates that have a more targeted effect within the GABA system.
Collapse
Affiliation(s)
- Sara M Schaefer
- a Department of Neurology , Yale School of Medicine, Yale University , New Haven , CT , USA
| | - Ana Vives Rodriguez
- a Department of Neurology , Yale School of Medicine, Yale University , New Haven , CT , USA
| | - Elan D Louis
- a Department of Neurology , Yale School of Medicine, Yale University , New Haven , CT , USA.,b Department of Chronic Disease Epidemiology , Yale School of Public Health, Yale University , New Haven , CT , USA.,c Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine , Yale University , New Haven , CT , USA
| |
Collapse
|
26
|
Vernon GM, Leiningen C, Thomas CA, Dunlop SR. Essential tremor & Parkinson disease: Recognizing the differences. Nurse Pract 2017; 42:35-40. [PMID: 28926496 DOI: 10.1097/01.npr.0000524667.01599.d0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Tremor is a common movement disorder in adults and older adults. There are many different types of tremor and many conditions that present with tremor as a symptom. This article discusses the causes of tremor, and through the use of a case study, helps NPs understand the assessment of tremor and differentiate two common neurologic disorders that can present with tremor: essential tremor and Parkinson disease.
Collapse
Affiliation(s)
- Gwyn M Vernon
- Gwyn M. Vernon is an NP at the University of Pennsylvania, Parkinson's Disease and Movement Disorders Center, Philadelphia, Pa., and national director of the Edmond J. Safra Visiting Nurse Faculty Program at the Parkinson's Foundation, Miami, Fla. Cathi A. Thomas is the program director of the Boston University Parkinson's Disease and Movement Disorders Center and assistant clinical professor in neurology at Boston University, Boston, Mass. Cheryl A. Leiningen is an assistant professor at the Monmouth University Marjorie K. Unterberg School of Nursing and Health Studies, West Long Branch, N.J. Susan R. Dunlop is the former associate director of the Johns Hopkins Parkinson's Disease and Movement Disorder Center, Baltimore, Md
| | | | | | | |
Collapse
|
27
|
Tremor dominant Kyoto (Trdk) rats carry a missense mutation in the gene encoding the SK2 subunit of small-conductance Ca 2+-activated K + channel. Brain Res 2017; 1676:38-45. [PMID: 28917524 DOI: 10.1016/j.brainres.2017.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 11/22/2022]
Abstract
Tremor dominant Kyoto (Trdk) is an autosomal dominant mutation that appeared in F344/NSlc rats mutagenized with N-ethyl-N-nitrosourea (ENU). In this study, we characterized and genetically analyzed F344-Trdk/+ heterozygous rats. The rats exhibited a tremor that was especially evident around weaning but persisted throughout life. The tremors of F344-Trdk/+ rats were attenuated by drugs effective against essential tremor (ET) but not drugs used to treat Parkinson's disease-related tremor, indicating that the pharmacological phenotype of F344-Trdk/+ rats was similar to human ET. Using positional candidate approach, we identified the Trdk mutation as a missense substitution (c. 866T>A, p. I289N) in Kcnn2, which encodes the SK2 subunit of the small-conductance Ca2+-activated K+ channel. In vitro electrophysiological studies revealed that the I289N mutation diminished SK2 channel activity. These findings demonstrate that F344-Trdk/+ rats represent a novel model of ET, and strongly suggest that Kcnn2 is the causative gene for the tremor phenotype in F344-Trdk/+ rats.
Collapse
|
28
|
Abdulrahman AA, Faisal K, Meshref AAA, Arshaduddin M. Low-dose acute vanillin is beneficial against harmaline-induced tremors in rats. Neurol Res 2017; 39:264-270. [DOI: 10.1080/01616412.2016.1275456] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
| | - Kunnathodi Faisal
- Scientific Research Center, Medical Services Department, Riyadh, Saudi Arabia
| | - Ali Al Amri Meshref
- Department of Pharmacy and Pharmaceutical Sciences, Medical Services Department, Riyadh, Saudi Arabia
| | | |
Collapse
|