1
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Bhat MA, Grampp T, Benke D. ERK1/2-Dependent Phosphorylation of GABA B1(S867/T872), Controlled by CaMKIIβ, Is Required for GABA B Receptor Degradation under Physiological and Pathological Conditions. Int J Mol Sci 2023; 24:13436. [PMID: 37686242 PMCID: PMC10488028 DOI: 10.3390/ijms241713436] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
GABAB receptor-mediated inhibition is indispensable for maintaining a healthy neuronal excitation/inhibition balance. Many neurological diseases are associated with a disturbed excitation/inhibition balance and downregulation of GABAB receptors due to enhanced sorting of the receptors to lysosomal degradation. A key event triggering the downregulation of the receptors is the phosphorylation of S867 in the GABAB1 subunit mediated by CaMKIIβ. Interestingly, close to S867 in GABAB1 exists another phosphorylation site, T872. Therefore, the question arose as to whether phosphorylation of T872 is involved in downregulating the receptors and whether phosphorylation of this site is also mediated by CaMKIIβ or by another protein kinase. Here, we show that mutational inactivation of T872 in GABAB1 prevented the degradation of the receptors in cultured neurons. We found that, in addition to CaMKIIβ, also ERK1/2 is involved in the degradation pathway of GABAB receptors under physiological and ischemic conditions. In contrast to our previous view, CaMKIIβ does not appear to directly phosphorylate S867. Instead, the data support a mechanism in which CaMKIIβ activates ERK1/2, which then phosphorylates S867 and T872 in GABAB1. Blocking ERK activity after subjecting neurons to ischemic stress completely restored downregulated GABAB receptor expression to normal levels. Thus, preventing ERK1/2-mediated phosphorylation of S867/T872 in GABAB1 is an opportunity to inhibit the pathological downregulation of the receptors after ischemic stress and is expected to restore a healthy neuronal excitation/inhibition balance.
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Affiliation(s)
- Musadiq A. Bhat
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; (M.A.B.); (T.G.)
| | - Thomas Grampp
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; (M.A.B.); (T.G.)
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; (M.A.B.); (T.G.)
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland
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2
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Dergunova LV, Filippenkov IB, Limborska SA, Myasoedov NF. Neuroprotective Peptides and New Strategies for Ischemic Stroke Drug Discoveries. Genes (Basel) 2023; 14:genes14050953. [PMID: 37239313 DOI: 10.3390/genes14050953] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/15/2023] [Accepted: 04/20/2023] [Indexed: 05/28/2023] Open
Abstract
Ischemic stroke continues to be one of the leading causes of death and disability in the adult population worldwide. The currently used pharmacological methods for the treatment of ischemic stroke are not effective enough and require the search for new tools and approaches to identify therapeutic targets and potential neuroprotectors. Today, in the development of neuroprotective drugs for the treatment of stroke, special attention is paid to peptides. Namely, peptide action is aimed at blocking the cascade of pathological processes caused by a decrease in blood flow to the brain tissues. Different groups of peptides have therapeutic potential in ischemia. Among them are small interfering peptides that block protein-protein interactions, cationic arginine-rich peptides with a combination of various neuroprotective properties, shuttle peptides that ensure the permeability of neuroprotectors through the blood-brain barrier, and synthetic peptides that mimic natural regulatory peptides and hormones. In this review, we consider the latest achievements and trends in the development of new biologically active peptides, as well as the role of transcriptomic analysis in identifying the molecular mechanisms of action of potential drugs aimed at the treatment of ischemic stroke.
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Affiliation(s)
- Lyudmila V Dergunova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
| | - Ivan B Filippenkov
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
| | - Svetlana A Limborska
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
| | - Nikolay F Myasoedov
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
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3
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Lu MF, Fu Q, Qiu TY, Yang JH, Peng QH, Hu ZZ. The CaMKII-dependent phosphorylation of GABA B receptors in the nucleus accumbens was involved in cocaine-induced behavioral sensitization in rats. CNS Neurosci Ther 2023; 29:1345-1356. [PMID: 36756679 PMCID: PMC10068462 DOI: 10.1111/cns.14107] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Previous studies have established that the regulation of prolonged, distal neuronal inhibition by the GABAB heteroreceptor (GABAB R) is determined by its stability, and hence residence time, on the plasma membrane. AIMS Here, we show that GABAB R in the nucleus accumbens (NAc) of rats affects the development of cocaine-induced behavioral sensitization by mediating its perinucleus internalization and membrane expression. MATERIALS & METHODS By immunofluorescent labeling, flow cytometry analysis, Co-immunoprecipitation and open field test, we measured the role of Ca2+ /calmodulin-dependent protein kinase II (CaMKII) to the control of GABAB R membrane anchoring and cocaine induced-behavioral sensitization. RESULTS Repeated cocaine treatment in rats (15 mg/kg) significantly decreases membrane levels of GABAB1 R and GABAB2 R in the NAc after day 3, 5 and 7. The membrane fluorescence and protein levels of GABAB R was also decreased in NAc GAD67 + neurons post cocaine (1 μM) treatment after 5 min. Moreover, the majority of internalized GABAB1 Rs exhibited perinuclear localization, a decrease in GABAB1 R-pHluroin signals was observed in cocaine-treated NAc neurons. By contrast, membrane expression of phosphorylated CaMKII (pCaMKII) post cocaine treatment was significantly increased after day 1, 3, 5 and 7. Baclofen blocked the cocaine induced behavioral sensitization via inhibition of cocaine enhanced-pCaMKII-GABAB1 R interaction. CONCLUSION These findings reveal a new mechanism by which pCaMKII-GABAB R signaling can promote psychostimulant-induced behavioral sensitization.
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Affiliation(s)
- Ming F Lu
- Department of Pathophysiology, College of Basic Medicine, Nanchang University, Nanchang, Jiangxi, China.,Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology, Department of Pathology, Schools of Basic Medical Sciences and Pharmaceutical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Qiang Fu
- Department of Respiration, Department Two, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, China
| | - Tian Y Qiu
- Department of Pathophysiology, College of Basic Medicine, Nanchang University, Nanchang, Jiangxi, China.,Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology, Department of Pathology, Schools of Basic Medical Sciences and Pharmaceutical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Jian H Yang
- Department of Physiology, College of Basic Medicine, Nanchang University, Nanchang, Jiangxi, China
| | - Qing H Peng
- Department of Anesthesiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
| | - Zhen Z Hu
- Department of Pathophysiology, College of Basic Medicine, Nanchang University, Nanchang, Jiangxi, China.,Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology, Department of Pathology, Schools of Basic Medical Sciences and Pharmaceutical Sciences, Nanchang University, Nanchang, Jiangxi, China
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4
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Hleihil M, Balakrishnan K, Benke D. Protein phosphatase 2A regulation of GABAB receptors normalizes ischemia-induced aberrant receptor trafficking and provides neuroprotection. Front Mol Neurosci 2022; 15:1015906. [PMID: 36311027 PMCID: PMC9607930 DOI: 10.3389/fnmol.2022.1015906] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
One major factor regulating the strength of GABAB receptor signaling and thereby neuronal excitability is the dynamic control of their cell surface expression. GABAB receptors are constitutively internalized and recycled back to the plasma membrane to maintain a stable number of receptors at cell surface for appropriate signaling. Protein phosphatase 2A (PP2A) dependent dephosphorylation of serine 783 (S783) in the GABAB2 subunit is a key event for downregulating GABAB receptor cell surface expression particularly under conditions associated with excitotoxicity. Here, we investigated the role of PP2A in regulating GABAB receptor cell surface expression under physiological and excitotoxic conditions. For this purpose, we developed an interfering peptide (PP2A-Pep) that inhibits the interaction of GABAB receptors with PP2A. Using cultured cortical neurons, we found that PP2A downregulates GABAB receptor cell surface expression by inhibiting recycling of the receptors and thereby promoting degradation of the receptors. Inhibition of the GABAB receptor/PP2A interaction by PP2A-Pep in cultured cortical neurons restored GABAB receptor cell surface expression after excitotoxic stress and inhibited progressing neuronal death even when added 48 h after the insult. To explore the therapeutic potential of PP2A-Pep, we further analyzed effect of PP2A-Pep in the middle cerebral artery occlusion (MCAO) mouse model of cerebral ischemia. Incubation of brain slices prepared from MCAO-treated mice with PP2A-Pep restored normal GABAB receptor expression and GABAB receptor-mediated inhibition, reduced ischemic-induced overexcitability of neurons, and prevented neuronal death in the ischemic penumbra. This data illustrates the crucial role of regulating GABAB receptor phosphorylation by PP2A for controlling neuronal inhibition and excitability. The results further suggest that interfering with the GABAB receptor/PP2A interaction is a promising strategy for the development of specific therapeutic interventions to treat neurological diseases associated with a disturbed excitation/inhibition balance and downregulation of GABAB receptors.
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Affiliation(s)
- Mohammad Hleihil
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zürich, Zurich, Switzerland
| | - Karthik Balakrishnan
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zürich, Zurich, Switzerland
- Drug Discovery Network Zurich, Zurich, Switzerland
- *Correspondence: Dietmar Benke,
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5
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Unravelling biological roles and mechanisms of GABA BR on addiction and depression through mood and memory disorders. Biomed Pharmacother 2022; 155:113700. [PMID: 36152411 DOI: 10.1016/j.biopha.2022.113700] [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: 08/12/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/23/2022] Open
Abstract
The metabotropic γ-aminobutyric acid type B receptor (GABABR) remains a hotspot in the recent research area. Being an idiosyncratic G-protein coupled receptor family member, the GABABR manifests adaptively tailored functionality under multifarious modulations by a constellation of agents, pointing to cross-talk between receptors and effectors that converge on the domains of mood and memory. This review systematically summarizes the latest achievements in signal transduction mechanisms of the GABABR-effector-regulator complex and probes how the up-and down-regulation of membrane-delimited GABABRs are associated with manifold intrinsic and extrinsic agents in synaptic strength and plasticity. Neuropsychiatric conditions depression and addiction share the similar pathophysiology of synapse inadaptability underlying negative mood-related processes, memory formations, and impairments. In the attempt to emphasize all convergent discoveries, we hope the insights gained on the GABABR system mechanisms of action are conducive to designing more therapeutic candidates so as to refine the prognosis rate of diseases and minimize side effects.
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6
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Bice AR, Xiao Q, Kong J, Yan P, Rosenthal ZP, Kraft AW, Smith KP, Wieloch T, Lee JM, Culver JP, Bauer AQ. Homotopic contralesional excitation suppresses spontaneous circuit repair and global network reconnections following ischemic stroke. eLife 2022; 11:e68852. [PMID: 35723585 PMCID: PMC9333991 DOI: 10.7554/elife.68852] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/14/2022] [Indexed: 11/16/2022] Open
Abstract
Understanding circuit-level manipulations that affect the brain's capacity for plasticity will inform the design of targeted interventions that enhance recovery after stroke. Following stroke, increased contralesional activity (e.g. use of the unaffected limb) can negatively influence recovery, but it is unknown which specific neural connections exert this influence, and to what extent increased contralesional activity affects systems- and molecular-level biomarkers of recovery. Here, we combine optogenetic photostimulation with optical intrinsic signal imaging to examine how contralesional excitatory activity affects cortical remodeling after stroke in mice. Following photothrombosis of left primary somatosensory forepaw (S1FP) cortex, mice either recovered spontaneously or received chronic optogenetic excitation of right S1FP over the course of 4 weeks. Contralesional excitation suppressed perilesional S1FP remapping and was associated with abnormal patterns of stimulus-evoked activity in the unaffected limb. This maneuver also prevented the restoration of resting-state functional connectivity (RSFC) within the S1FP network, RSFC in several networks functionally distinct from somatomotor regions, and resulted in persistent limb-use asymmetry. In stimulated mice, perilesional tissue exhibited transcriptional changes in several genes relevant for recovery. Our results suggest that contralesional excitation impedes local and global circuit reconnection through suppression of cortical activity and several neuroplasticity-related genes after stroke, and highlight the importance of site selection for targeted therapeutic interventions after focal ischemia.
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Affiliation(s)
- Annie R Bice
- Department of Radiology, Washington University in St. LouisSaint LouisUnited States
| | - Qingli Xiao
- Department of Neurology, Washington University in St. LouisSaint LouisUnited States
| | - Justin Kong
- Department of Biology, Washington University in St. LouisSaint LouisUnited States
| | - Ping Yan
- Department of Neurology, Washington University in St. LouisSaint LouisUnited States
| | | | - Andrew W Kraft
- Department of Neurology, Washington University in St. LouisSaint LouisUnited States
| | - Karen P Smith
- Department of Neurology, Washington University in St. LouisSaint LouisUnited States
| | | | - Jin-Moo Lee
- Department of Neurology, Washington University in St. LouisSaint LouisUnited States
| | - Joseph P Culver
- Department of Radiology, Washington University in St. LouisSt. LouisUnited States
| | - Adam Q Bauer
- Department of Radiology, Washington University in St. LouisSaint LouisUnited States
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7
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Balakrishnan K, Hleihil M, Bhat MA, Ganley RP, Vaas M, Klohs J, Zeilhofer HU, Benke D. Targeting the interaction of GABA B receptors with CaMKII with an interfering peptide restores receptor expression after cerebral ischemia and inhibits progressive neuronal death in mouse brain cells and slices. Brain Pathol 2022; 33:e13099. [PMID: 35698024 PMCID: PMC9836377 DOI: 10.1111/bpa.13099] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/29/2022] [Indexed: 01/21/2023] Open
Abstract
Cerebral ischemia is the leading cause for long-term disability and mortality in adults due to massive neuronal death. Currently, there is no pharmacological treatment available to limit progressive neuronal death after stroke. A major mechanism causing ischemia-induced neuronal death is the excessive release of glutamate and the associated overexcitation of neurons (excitotoxicity). Normally, GABAB receptors control neuronal excitability in the brain via prolonged inhibition. However, excitotoxic conditions rapidly downregulate GABAB receptors via a CaMKII-mediated mechanism and thereby diminish adequate inhibition that could counteract neuronal overexcitation and neuronal death. To prevent the deleterious downregulation of GABAB receptors, we developed a cell-penetrating synthetic peptide (R1-Pep) that inhibits the interaction of GABAB receptors with CaMKII. Administration of this peptide to cultured cortical neurons exposed to excitotoxic conditions restored cell surface expression and function of GABAB receptors. R1-Pep did not affect CaMKII expression or activity but prevented its T286 autophosphorylation that renders it autonomously and persistently active. Moreover, R1-Pep counteracted the aberrant downregulation of G protein-coupled inwardly rectifying K+ channels and the upregulation of N-type voltage-gated Ca2+ channels, the main effectors of GABAB receptors. The restoration of GABAB receptors activated the Akt survival pathway and inhibited excitotoxic neuronal death with a wide time window in cultured neurons. Restoration of GABAB receptors and neuroprotective activity of R1-Pep was verified by using brain slices prepared from mice after middle cerebral artery occlusion (MCAO). Treatment with R1-Pep restored normal GABAB receptor expression and GABA receptor-mediated K+ channel currents. This reduced MCAO-induced neuronal excitability and inhibited neuronal death. These results support the hypothesis that restoration of GABAB receptor expression under excitatory conditions provides neuroprotection and might be the basis for the development of a selective intervention to inhibit progressive neuronal death after ischemic stroke.
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Affiliation(s)
- Karthik Balakrishnan
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Present address:
Dewpoint Therapeutics GMBHDresdenGermany
| | - Mohammad Hleihil
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland
| | - Musadiq A. Bhat
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland
| | - Robert P. Ganley
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland
| | - Markus Vaas
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Present address:
Clinical Trial Center ZurichUniversity Hospital of ZurichZurichSwitzerland
| | - Jan Klohs
- Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Institute for Biomedical Engineering, University of Zurich and ETH ZurichZurichSwitzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Drug Discovery Network ZurichZurichSwitzerland,Institute of Pharmaceutical Sciences, ETH ZurichZurichSwitzerland
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Drug Discovery Network ZurichZurichSwitzerland
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8
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Mechanisms and Regulation of Neuronal GABA B Receptor-Dependent Signaling. Curr Top Behav Neurosci 2020; 52:39-79. [PMID: 32808092 DOI: 10.1007/7854_2020_129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
γ-Aminobutyric acid B receptors (GABABRs) are broadly expressed throughout the central nervous system where they play an important role in regulating neuronal excitability and synaptic transmission. GABABRs are G protein-coupled receptors that mediate slow and sustained inhibitory actions via modulation of several downstream effector enzymes and ion channels. GABABRs are obligate heterodimers that associate with diverse arrays of proteins to form modular complexes that carry out distinct physiological functions. GABABR-dependent signaling is fine-tuned and regulated through a multitude of mechanisms that are relevant to physiological and pathophysiological states. This review summarizes the current knowledge on GABABR signal transduction and discusses key factors that influence the strength and sensitivity of GABABR-dependent signaling in neurons.
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9
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Li X, Liao Y, Dong Y, Li S, Wang F, Wu R, Yuan Z, Cheng J. Mib2 Deficiency Inhibits Microglial Activation and Alleviates Ischemia-Induced Brain Injury. Aging Dis 2020; 11:523-535. [PMID: 32489699 PMCID: PMC7220279 DOI: 10.14336/ad.2019.0807] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/07/2019] [Indexed: 12/20/2022] Open
Abstract
Neuroinflammation plays a critical role in ischemia-induced brain injury. Mib2, an E3 ubiquitin ligase, has been reported to regulate Notch signaling and participate in the peripheral immune system. However, the roles of Mib2 in the nervous system are not well characterized. In this study, we show that Mib2 is involved in lipopolysaccharide (LPS)- and oxygen-glucose deprivation (OGD)-induced microglial activation. Mechanistically, Mib2 interacts with the IKK complex and regulates the activation of NF-κB signaling, thus modulating Notch1 transcription in the microglia. Furthermore, we generated a microglia-specific Mib2 knockout mice and found that microglia-specific deletion of Mib2 significantly alleviates ischemia-induced neuroinflammation and brain injury. Taken together, our results reveal a critical role of Mib2 in microglial activation and ischemia-induced brain injury, thus providing a potential target for the treatment of stroke.
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Affiliation(s)
- Xiaoheng Li
- 1Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yajin Liao
- 2The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China.,3Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
| | - Yuan Dong
- 4Department of Biochemistry, Medical College, Qingdao University, Qingdao, Shandong, China
| | - Shuoshuo Li
- 5The State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Fengchao Wang
- 6National Institute of Biological Sciences, Beijing, China
| | - Rong Wu
- 2The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Zengqiang Yuan
- 1Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,2The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Jinbo Cheng
- 2The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China.,3Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
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10
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McKenna MC, Schuck PF, Ferreira GC. Fundamentals of CNS energy metabolism and alterations in lysosomal storage diseases. J Neurochem 2018; 148:590-599. [PMID: 30144055 DOI: 10.1111/jnc.14577] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/05/2018] [Accepted: 08/22/2018] [Indexed: 01/03/2023]
Abstract
The brain has a very high requirement for energy. Adult brain relies on glucose as an energy substrate, whereas developing brain can utilize alternative substrates as well as glucose for energy and for the biosynthesis of lipids and proteins required for brain development. Metabolism provides the energy required to support all cellular functions and brain development and building blocks for macromolecules. Lysosomes are organelles involved in breakdown of biological compounds including proteins and complex lipids in the body and brain. Recent studies suggest that lysosomal dysfunction can damage neurons and/or alter neurotransmitter homeostasis. Several studies also implicate mitochondrial dysfunction in the pathophysiology of brain damage in lysosomal storage diseases. This manuscript provides a brief review of energy metabolism and the key pathways involved in metabolism in brain. Roles of lysosomes related to metabolism and neurotransmission are discussed, and evidence for mitochondrial dysfunction in several lysosomal storage diseases is presented. This article is part of the Special Issue "Lysosomal Storage Disorders".
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Affiliation(s)
- Mary C McKenna
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Patricia F Schuck
- School of Sciences, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Gustavo C Ferreira
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Rio Grande do Sul, Brazil
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11
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Ca 2+/Calmodulin-Dependent Protein Kinase II (CaMKII) β-Dependent Phosphorylation of GABA B1 Triggers Lysosomal Degradation of GABA B Receptors via Mind Bomb-2 (MIB2)-Mediated Lys-63-Linked Ubiquitination. Mol Neurobiol 2018; 56:1293-1309. [PMID: 29881949 PMCID: PMC6401210 DOI: 10.1007/s12035-018-1142-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/22/2018] [Indexed: 12/12/2022]
Abstract
The G protein-coupled GABAB receptors, constituted from GABAB1 and GABAB2 subunits, are important regulators of neuronal excitability by mediating long-lasting inhibition. One factor that determines receptor availability and thereby the strength of inhibition is regulated protein degradation. GABAB receptors are constitutively internalized from the plasma membrane and are either recycled to the cell surface or degraded in lysosomes. Lys-63-linked ubiquitination mediated by the E3 ligase Mind bomb-2 (MIB2) is the signal that sorts GABAB receptors to lysosomes. However, it is unknown how Lys-63-linked ubiquitination and thereby lysosomal degradation of the receptors is regulated. Here, we show that Ca2+/calmodulin-dependent protein kinase II (CaMKII) promotes MIB2-mediated Lys-63-linked ubiquitination of GABAB receptors. We found that inhibition of CaMKII in cultured rat cortical neurons increased cell surface GABAB receptors, whereas overexpression of CaMKIIβ, but not CaMKIIα, decreased receptor levels. This effect was conveyed by Lys-63-linked ubiquitination of GABAB1 at multiple sites mediated by the E3 ligase MIB2. Inactivation of the CaMKII phosphorylation site on GABAB1(Ser-867) strongly reduced Lys-63-linked ubiquitination of GABAB receptors and increased their cell surface expression, whereas the phosphomimetic mutant GABAB1(S867D) exhibited strongly increased Lys-63-linked ubiquitination and reduced cell surface expression. Finally, triggering lysosomal degradation of GABAB receptors by sustained activation of glutamate receptors, a condition occurring in brain ischemia, was accompanied with a massive increase of GABAB1(Ser-867) phosphorylation-dependent Lys-63-linked ubiquitination of GABAB receptors. These findings indicate that CaMKIIβ-dependent Lys-63-linked ubiquitination of GABAB1 at multiple sites controls sorting of GABAB receptors to lysosomes for degradation under physiological and pathological condition.
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12
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Yu J, Qin B, Moyer AM, Nowsheen S, Liu T, Qin S, Zhuang Y, Liu D, Lu SW, Kalari KR, Visscher DW, Copland JA, McLaughlin SA, Moreno-Aspitia A, Northfelt DW, Gray RJ, Lou Z, Suman VJ, Weinshilboum R, Boughey JC, Goetz MP, Wang L. DNA methyltransferase expression in triple-negative breast cancer predicts sensitivity to decitabine. J Clin Invest 2018; 128:2376-2388. [PMID: 29708513 DOI: 10.1172/jci97924] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/13/2018] [Indexed: 01/22/2023] Open
Abstract
Triple-negative breast cancer (TNBC) is a heterogeneous disease with poor prognosis that lacks targeted therapies, especially in patients with chemotherapy-resistant disease. Since DNA methylation-induced silencing of tumor suppressors is common in cancer, reversal of promoter DNA hypermethylation by 5-aza-2'-deoxycytidine (decitabine), an FDA-approved DNA methyltransferase (DNMT) inhibitor, has proven effective in treating hematological neoplasms. However, its antitumor effect varies in solid tumors, stressing the importance of identifying biomarkers predictive of therapeutic response. Here, we focused on the identification of biomarkers to select decitabine-sensitive TNBC through increasing our understanding of the mechanism of decitabine action. We showed that protein levels of DNMTs correlated with response to decitabine in patient-derived xenograft (PDX) organoids originating from chemotherapy-sensitive and -resistant TNBCs, suggesting DNMT levels as potential biomarkers of response. Furthermore, all 3 methytransferases, DNMT1, DNMT3A, and DNMT3B, were degraded following low-concentration, long-term decitabine treatment both in vitro and in vivo. The DNMT proteins could be ubiquitinated by the E3 ligase, TNF receptor-associated factor 6 (TRAF6), leading to lysosome-dependent protein degradation. Depletion of TRAF6 blocked decitabine-induced DNMT degradation, conferring resistance to decitabine. Our study suggests a potential mechanism of regulating DNMT protein degradation and DNMT levels as response biomarkers for DNMT inhibitors in TNBCs.
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Affiliation(s)
- Jia Yu
- Department of Molecular Pharmacology and Experimental Therapeutics
| | - Bo Qin
- Department of Molecular Pharmacology and Experimental Therapeutics.,Department of Oncology, and
| | - Ann M Moyer
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Somaira Nowsheen
- Department of Oncology, and.,Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Medicine and the Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota, USA
| | - Tongzheng Liu
- Department of Oncology, and.,Jinan University Institute of Tumor Pharmacology, Guangzhou, China
| | - Sisi Qin
- Department of Molecular Pharmacology and Experimental Therapeutics
| | - Yongxian Zhuang
- Department of Molecular Pharmacology and Experimental Therapeutics
| | - Duan Liu
- Department of Molecular Pharmacology and Experimental Therapeutics
| | - Shijia W Lu
- Department of Molecular Pharmacology and Experimental Therapeutics.,Sydney Medical School, University of Sydney, New South Wales, Australia
| | - Krishna R Kalari
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA
| | - Daniel W Visscher
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | | | | | - Richard J Gray
- Department of Surgery, Mayo Clinic, Scottsdale, Arizona, USA
| | | | - Vera J Suman
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Judy C Boughey
- Department of Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Matthew P Goetz
- Department of Molecular Pharmacology and Experimental Therapeutics.,Department of Oncology, and
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics
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TERUNUMA M. Diversity of structure and function of GABA B receptors: a complexity of GABA B-mediated signaling. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:390-411. [PMID: 30541966 PMCID: PMC6374141 DOI: 10.2183/pjab.94.026] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 10/09/2018] [Indexed: 05/24/2023]
Abstract
γ-aminobutyric acid type B (GABAB) receptors are broadly expressed in the nervous system and play an important role in neuronal excitability. GABAB receptors are G protein-coupled receptors that mediate slow and prolonged inhibitory action, via activation of Gαi/o-type proteins. GABAB receptors mediate their inhibitory action through activating inwardly rectifying K+ channels, inactivating voltage-gated Ca2+ channels, and inhibiting adenylate cyclase. Functional GABAB receptors are obligate heterodimers formed by the co-assembly of R1 and R2 subunits. It is well established that GABAB receptors interact not only with G proteins and effectors but also with various proteins. This review summarizes the structure, subunit isoforms, and function of GABAB receptors, and discusses the complexity of GABAB receptors, including how receptors are localized in specific subcellular compartments, the mechanism regulating cell surface expression and mobility of the receptors, and the diversity of receptor signaling through receptor crosstalk and interacting proteins.
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Affiliation(s)
- Miho TERUNUMA
- Division of Oral Biochemistry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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14
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Saha SS, Caviness G, Yi G, Raymond EL, Mbow ML, Kao CC. E3 Ubiquitin Ligase RNF125 Activates Interleukin-36 Receptor Signaling and Contributes to Its Turnover. J Innate Immun 2017; 10:56-69. [PMID: 29176319 DOI: 10.1159/000481210] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 09/04/2017] [Indexed: 12/14/2022] Open
Abstract
Signaling by the interleukin-36 receptor (IL-36R) is linked to inflammatory diseases such as psoriasis. However, the regulation of IL-36R signaling is poorly understood. Activation of IL-36R signaling in cultured cells results in an increased polyubiquitination of the receptor subunit, IL-1Rrp2. Treatment with deubiquitinases shows that the receptor subunit of IL-36R, IL-1Rrp2, is primarily polyubiquitinated at the K63 position, which is associated with endocytic trafficking and signal transduction. A minor amount of ubiquitination is at the K48 position that is associated with protein degradation. A focused siRNA screen identified RNF125, an E3 ubiquitin ligase, to ubiquitinate IL-1Rrp2 upon activation of IL-36R signaling while not affecting the activated IL-1 receptor. Knockdown of RNF125 decreases signal transduction by the IL-36R. Overexpression of RNF125 in HEK293T cells activates IL-36R signaling and increases the ubiquitination of IL-1Rrp2 and its subsequent turnover. RNF125 can coimmunoprecipitate with the IL-36R, and it traffics with IL-1Rrp2 from the cell surface to lysosomes. Mutations of Lys568 and Lys569 in the C-terminal tail of IL-1Rrp2 decrease ubiquitination by RNF125 and increase the steady-state levels of IL-1Rrp2. These results demonstrate that RNF125 has multiple regulatory roles in the signaling, trafficking, and turnover of the IL-36R.
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Affiliation(s)
- Siddhartha S Saha
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
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15
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Hochrainer K. Protein Modifications with Ubiquitin as Response to Cerebral Ischemia-Reperfusion Injury. Transl Stroke Res 2017; 9:157-173. [DOI: 10.1007/s12975-017-0567-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/11/2017] [Accepted: 08/17/2017] [Indexed: 12/12/2022]
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