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Shen NX, Qu XC, Yu J, Fan CX, Min FL, Li LY, Zhang MR, Li BM, Wang J, He N, Liao WP, Shi YW, Li WB. NUS1 Variants Cause Lennox-Gastaut Syndrome Related to Unfolded Protein Reaction Activation. Mol Neurobiol 2024:10.1007/s12035-024-04123-6. [PMID: 38520610 DOI: 10.1007/s12035-024-04123-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/12/2024] [Indexed: 03/25/2024]
Abstract
NUS1 encodes the Nogo-B receptor, a critical regulator for unfolded protein reaction (UPR) signaling. Although several loss-of-function variants of NUS1 have been identified in patients with developmental and epileptic encephalopathy (DEE), the role of the NUS1 variant in Lennox-Gastaut syndrome (LGS), a severe child-onset DEE, remains unknown. In this study, we identified two de novo variants of NUS1, a missense variant (c.868 C > T/p.R290C) and a splice site variant (c.792-2 A > G), in two unrelated LGS patients using trio-based whole-exome sequencing performed in a cohort of 165 LGS patients. Both variants were absent in the gnomAD population and showed a significantly higher observed number of variants than expected genome-wide. The R290C variant was predicted to damage NUS1 and decrease its protein stability. The c.792-2 A > G variant caused premature termination of the protein. Knockdown of NUS1 activated the UPR pathway, resulting in apoptosis of HEK293T cells. Supplementing cells with expression of wild-type NUS1, but not the mutant (R290C), rescued UPR activation and apoptosis in NUS1 knockdown cells. Compared to wild-type Drosophila, seizure-like behaviors and excitability in projection neurons were significantly increased in Tango14 (homolog of human NUS1) knockdown and Tango14R290C/+ knock-in Drosophila. Additionally, abnormal development and a small body size were observed in both mutants. Activated UPR signaling was also detected in both mutants. Thus, NUS1 is a causative gene for LGS with dominant inheritance. The pathogenicity of these variants is related to the UPR signaling activation, which may be a common pathogenic mechanism of DEE.
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Affiliation(s)
- Nan-Xiang Shen
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Xiao-Chong Qu
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Jing Yu
- Neurology Department, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumchi, China
| | - Cui-Xia Fan
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Fu-Li Min
- Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Ling-Ying Li
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Ming-Rui Zhang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Bing-Mei Li
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Jie Wang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Na He
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Wei-Ping Liao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Yi-Wu Shi
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China.
| | - Wen-Bin Li
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China.
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Martin SP, Leeman-Markowski BA. Proposed mechanisms of tau: relationships to traumatic brain injury, Alzheimer's disease, and epilepsy. Front Neurol 2024; 14:1287545. [PMID: 38249745 PMCID: PMC10797726 DOI: 10.3389/fneur.2023.1287545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/30/2023] [Indexed: 01/23/2024] Open
Abstract
Traumatic brain injury (TBI), Alzheimer's disease (AD), and epilepsy share proposed mechanisms of injury, including neuronal excitotoxicity, cascade signaling, and activation of protein biomarkers such as tau. Although tau is typically present intracellularly, in tauopathies, phosphorylated (p-) and hyper-phosphorylated (hp-) tau are released extracellularly, the latter leading to decreased neuronal stability and neurofibrillary tangles (NFTs). Tau cleavage at particular sites increases susceptibility to hyper-phosphorylation, NFT formation, and eventual cell death. The relationship between tau and inflammation, however, is unknown. In this review, we present evidence for an imbalanced endoplasmic reticulum (ER) stress response and inflammatory signaling pathways resulting in atypical p-tau, hp-tau and NFT formation. Further, we propose tau as a biomarker for neuronal injury severity in TBI, AD, and epilepsy. We present a hypothesis of tau phosphorylation as an initial acute neuroprotective response to seizures/TBI. However, if the underlying seizure pathology or TBI recurrence is not effectively treated, and the pathway becomes chronically activated, we propose a "tipping point" hypothesis that identifies a transition of tau phosphorylation from neuroprotective to injurious. We outline the role of amyloid beta (Aβ) as a "last ditch effort" to revert the cell to programmed death signaling, that, when fails, transitions the mechanism from injurious to neurodegenerative. Lastly, we discuss targets along these pathways for therapeutic intervention in AD, TBI, and epilepsy.
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Affiliation(s)
- Samantha P. Martin
- Comprehensive Epilepsy Center, New York University Langone Health, New York, NY, United States
- Department of Neurology, New York University Langone Health, New York, NY, United States
- New York University Grossman School of Medicine, New York, NY, United States
- VA New York Harbor Healthcare System, New York, NY, United States
| | - Beth A. Leeman-Markowski
- Comprehensive Epilepsy Center, New York University Langone Health, New York, NY, United States
- Department of Neurology, New York University Langone Health, New York, NY, United States
- VA New York Harbor Healthcare System, New York, NY, United States
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Madhamanchi K, Madhamanchi P, Jayalakshmi S, Panigrahi M, Patil A, Phanithi PB. Dopamine and Glutamate Crosstalk Worsen the Seizure Outcome in TLE-HS Patients. Mol Neurobiol 2023; 60:4952-4965. [PMID: 37209264 DOI: 10.1007/s12035-023-03361-4] [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: 10/18/2022] [Accepted: 04/19/2023] [Indexed: 05/22/2023]
Abstract
Temporal lobe epilepsy (TLE), accompanied by hippocampal sclerosis (HS), is the most common form of drug-resistant epilepsy (DRE). Nearly 20% of the patients showed seizure recurrence even after surgery, and the reasons are yet to be understood. Dysregulation of neurotransmitters is evident during seizures, which can induce excitotoxicity. The present study focused on understanding the molecular changes associated with Dopamine (DA) and glutamate signaling and their possible impact on the persistence of excitotoxicity and seizure recurrence in patients with drug-resistant TLE-HS who underwent surgery. According to the International League against Epilepsy (ILAE) suggested classification for seizure outcomes, the patients (n = 26) were classified as class 1 (no seizures) and class 2 (persistent seizures) using the latest post-surgery follow-up data to understand the prevalent molecular changes in seizure-free and seizure-recurrence patient groups. Our study uses thioflavin T assay, western blot analysis, immunofluorescence assays, and fluorescence resonance energy transfer (FRET) assays. We have observed a substantial increase in the DA and glutamate receptors that promote excitotoxicity. Patients who had seizure recurrence showed a significant increase in (pNR2B, p < 0.009; and pGluR1, p < 0.01), protein phosphatase1γ (PP1γ; p < 0.009), protein kinase A (PKAc; p < 0.001) and dopamine-cAMP regulated phospho protein32 (pDARPP32T34; p < 0.009) which are critical for long-term potentiation (LTP), excitotoxicity compared to seizure-free patients and controls. A significant increase in D1R downstream kinases like PKA (p < 0.001), pCAMKII (p < 0.009), and Fyn (p < 0.001) was observed in patient samples compared to controls. Anti-epileptic DA receptor D2R was found to be decreased in ILAE class 2 (p < 0.02) compared to class 1. Since upregulation of DA and glutamate signaling supports LTP and excitotoxicity, we believe it could impact seizure recurrence. Further studies about the impact of DA and glutamate signaling on the distribution of PP1γ at postsynaptic density and synaptic strength could help us understand the seizure microenvironment in patients. Dopamine, Glutamate signal crosstalk. Diagram representing the PP1γ regulation by NMDAR negative feedback inhibition signaling (green circle-left) and D1R signal (red circle-middle) domination over PP1γ though increased PKA, pDARPP32T34, and supports pGluR1, pNR2B in seizure recurrent patients. D1R-D2R hetero dimer activation (red circle-right) increases cellular Ca2+ and pCAMKIIα activation. All these events lead to calcium overload in HS patients and excitotoxicity, particularly in patients experiencing recurrent seizures.
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Affiliation(s)
- Kishore Madhamanchi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, 500046, India
| | - Pradeep Madhamanchi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, 500046, India
- Govt. Degree College for Men's, Srikakulam District, Andhra Pradesh, 532001, India
| | - Sita Jayalakshmi
- Department of Neurology, Krishna Institute of Medical Sciences (KIMS), Secunderabad, Telangana, India
| | - Manas Panigrahi
- Department of Neurology, Krishna Institute of Medical Sciences (KIMS), Secunderabad, Telangana, India
| | - Anuja Patil
- Department of Neurology, Krishna Institute of Medical Sciences (KIMS), Secunderabad, Telangana, India
| | - Prakash Babu Phanithi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, 500046, India.
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Murray GC, Bubier JA, Zinder OJ, Harris B, Clark J, Christopher MC, Hanley C, Tjong H, Li M, Ngan CY, Reinholdt L, Burgess RW, Tadenev ALD. An allelic series of spontaneous Rorb mutant mice exhibit a gait phenotype, changes in retina morphology and behavior, and gene expression signatures associated with the unfolded protein response. G3 (BETHESDA, MD.) 2023; 13:jkad131. [PMID: 37300435 PMCID: PMC10411600 DOI: 10.1093/g3journal/jkad131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
The Retinoid-related orphan receptor beta (RORβ) gene encodes a developmental transcription factor and has 2 predominant isoforms created through alternative first exon usage; one specific to the retina and another present more broadly in the central nervous system, particularly regions involved in sensory processing. RORβ belongs to the nuclear receptor family and plays important roles in cell fate specification in the retina and cortical layer formation. In mice, loss of RORβ causes disorganized retina layers, postnatal degeneration, and production of immature cone photoreceptors. Hyperflexion or "high-stepping" of rear limbs caused by reduced presynaptic inhibition by Rorb-expressing inhibitory interneurons of the spinal cord is evident in RORβ-deficient mice. RORβ variants in patients are associated with susceptibility to various neurodevelopmental conditions, primarily generalized epilepsies, but including intellectual disability, bipolar, and autism spectrum disorders. The mechanisms by which RORβ variants confer susceptibility to these neurodevelopmental disorders are unknown but may involve aberrant neural circuit formation and hyperexcitability during development. Here we report an allelic series in 5 strains of spontaneous Rorb mutant mice with a high-stepping gait phenotype. We show retinal abnormalities in a subset of these mutants and demonstrate significant differences in various behavioral phenotypes related to cognition. Gene expression analyses in all 5 mutants reveal a shared over-representation of the unfolded protein response and pathways related to endoplasmic reticulum stress, suggesting a possible mechanism of susceptibility relevant to patients.
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Affiliation(s)
- George C Murray
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | | | | | - James Clark
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | | | | | - Harianto Tjong
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Meihong Li
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Chew Yee Ngan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | | | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
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5
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Chen W, Zhang J, Zhang Y, Zhang J, Li W, Sha L, Xia Y, Chen L. Pharmacological modulation of autophagy for epilepsy therapy: opportunities and obstacles. Drug Discov Today 2023; 28:103600. [PMID: 37119963 DOI: 10.1016/j.drudis.2023.103600] [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: 12/30/2022] [Revised: 04/04/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023]
Abstract
Epilepsy (EP) is a long-term neurological disorder characterized by neuroinflammatory responses, neuronal apoptosis, imbalance between excitatory and inhibitory neurotransmitters, and oxidative stress in the brain. Autophagy is a process of cellular self-regulation to maintain normal physiological functions. Emerging evidence suggests that dysfunctional autophagy pathways in neurons are a potential mechanism underlying EP pathogenesis. In this review, we discuss current evidence and molecular mechanisms of autophagy dysregulation in EP and the probable function of autophagy in epileptogenesis. Moreover, we review the autophagy modulators reported for the treatment of EP models, and discuss the obstacles to, and opportunities for, the potential therapeutic applications of novel autophagy modulators as EP therapies. Teaser: Defective autophagy affects the onset and progression of epilepsy, and many anti-epileptic drugs have autophagy-modulating effects.
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Affiliation(s)
- Wenqing Chen
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jifa Zhang
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Yiwen Zhang
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jiaxian Zhang
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Wanling Li
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Leihao Sha
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Yilin Xia
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Lei Chen
- Department of Neurology, Joint Research Institution of Altitude Health and State Key Laboratory of Biotherapy and Cancer Center and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
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6
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Wang Z, Li Q, Kolls BJ, Mace B, Yu S, Li X, Liu W, Chaparro E, Shen Y, Dang L, Del Águila Á, Bernstock JD, Johnson KR, Yao J, Wetsel WC, Moore SD, Turner DA, Yang W. Sustained overexpression of spliced X-box-binding protein-1 in neurons leads to spontaneous seizures and sudden death in mice. Commun Biol 2023; 6:252. [PMID: 36894627 PMCID: PMC9998612 DOI: 10.1038/s42003-023-04594-8] [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: 06/25/2022] [Accepted: 02/14/2023] [Indexed: 03/11/2023] Open
Abstract
The underlying etiologies of seizures are highly heterogeneous and remain incompletely understood. While studying the unfolded protein response (UPR) pathways in the brain, we unexpectedly discovered that transgenic mice (XBP1s-TG) expressing spliced X-box-binding protein-1 (Xbp1s), a key effector of UPR signaling, in forebrain excitatory neurons, rapidly develop neurologic deficits, most notably recurrent spontaneous seizures. This seizure phenotype begins around 8 days after Xbp1s transgene expression is induced in XBP1s-TG mice, and by approximately 14 days post induction, the seizures evolve into status epilepticus with nearly continuous seizure activity followed by sudden death. Animal death is likely due to severe seizures because the anticonvulsant valproic acid could significantly prolong the lives of XBP1s-TG mice. Mechanistically, our gene profiling analysis indicates that compared to control mice, XBP1s-TG mice exhibit 591 differentially regulated genes (mostly upregulated) in the brain, including several GABAA receptor genes that are notably downregulated. Finally, whole-cell patch clamp analysis reveals a significant reduction in both spontaneous and tonic GABAergic inhibitory responses in Xbp1s-expressing neurons. Taken together, our findings unravel a link between XBP1s signaling and seizure occurrence.
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Affiliation(s)
- Zhuoran Wang
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Qiang Li
- Department of Neurology, Duke University Medical Center, Durham, NC, USA
| | - Brad J Kolls
- Department of Neurology, Duke University Medical Center, Durham, NC, USA
| | - Brian Mace
- Department of Neurology, Duke University Medical Center, Durham, NC, USA
| | - Shu Yu
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Xuan Li
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Wei Liu
- Department of Bioengineering, Duke University, Durham, NC, USA
| | - Eduardo Chaparro
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, USA
| | - Yuntian Shen
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Lihong Dang
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Ángela Del Águila
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Joshua D Bernstock
- National Institute of Neurological Disorders and Stroke, NINDS/NIH, Bethesda, MD, USA
| | - Kory R Johnson
- National Institute of Neurological Disorders and Stroke, NINDS/NIH, Bethesda, MD, USA
| | - Junjie Yao
- Department of Bioengineering, Duke University, Durham, NC, USA
| | - William C Wetsel
- Department of Neurology, Duke University Medical Center, Durham, NC, USA
- Departments of Neurobiology and Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Scott D Moore
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Dennis A Turner
- Departments of Neurosurgery, Neurobiology and Biomedical Engineering, Duke University Medical Center, Durham, NC, USA
| | - Wei Yang
- Multidisciplinary Brain Protection Program, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.
- Department of Neurology, Duke University Medical Center, Durham, NC, USA.
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