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Choi EJ, Oh HT, Lee SH, Zhang CS, Li M, Kim SY, Park S, Chang TS, Lee BH, Lin SC, Jeon SM. Metabolic stress induces a double-positive feedback loop between AMPK and SQSTM1/p62 conferring dual activation of AMPK and NFE2L2/NRF2 to synergize antioxidant defense. Autophagy 2024. [PMID: 38953310 DOI: 10.1080/15548627.2024.2374692] [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: 12/07/2023] [Accepted: 05/22/2024] [Indexed: 07/04/2024] Open
Abstract
Co-occurring mutations in KEAP1 in STK11/LKB1-mutant NSCLC activate NFE2L2/NRF2 to compensate for the loss of STK11-AMPK activity during metabolic adaptation. Characterizing the regulatory crosstalk between the STK11-AMPK and KEAP1-NFE2L2 pathways during metabolic stress is crucial for understanding the implications of co-occurring mutations. Here, we found that metabolic stress increased the expression and phosphorylation of SQSTM1/p62, which is essential for the activation of NFE2L2 and AMPK, synergizing antioxidant defense and tumor growth. The SQSTM1-driven dual activation of NFE2L2 and AMPK was achieved by inducing macroautophagic/autophagic degradation of KEAP1 and facilitating the AXIN-STK11-AMPK complex formation on the lysosomal membrane, respectively. In contrast, the STK11-AMPK activity was also required for metabolic stress-induced expression and phosphorylation of SQSTM1, suggesting a double-positive feedback loop between AMPK and SQSTM1. Mechanistically, SQSTM1 expression was increased by the PPP2/PP2A-dependent dephosphorylation of TFEB and TFE3, which was induced by the lysosomal deacidification caused by low glucose metabolism and AMPK-dependent proton reduction. Furthermore, SQSTM1 phosphorylation was increased by MAP3K7/TAK1, which was activated by ROS and pH-dependent secretion of lysosomal Ca2+. Importantly, phosphorylation of SQSTM1 at S24 and S226 was critical for the activation of AMPK and NFE2L2. Notably, the effects caused by metabolic stress were abrogated by the protons provided by lactic acid. Collectively, our data reveal a novel double-positive feedback loop between AMPK and SQSTM1 leading to the dual activation of AMPK and NFE2L2, potentially explaining why co-occurring mutations in STK11 and KEAP1 happen and providing promising therapeutic strategies for lung cancer.
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Affiliation(s)
- Eun-Ji Choi
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul, Korea
- College of Pharmacy, Ajou University, Suwon, Gyeonggi-do, Korea
| | - Hyun-Taek Oh
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul, Korea
- Department of BioHealth Regulatory Science, Graduate School of Ajou University, Suwon, Gyeonggi-do, Korea
| | - Seon-Hyeong Lee
- Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, Gyeonggi-do, Korea
| | - Chen-Song Zhang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Fujian, China
| | - Mengqi Li
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Fujian, China
| | - Soo-Youl Kim
- Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, Gyeonggi-do, Korea
| | - Sunghyouk Park
- Natural Products Research Institute and College of Pharmacy, Seoul National University, Seoul, Korea
| | - Tong-Shin Chang
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul, Korea
| | - Byung-Hoon Lee
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul, Korea
| | - Sheng-Cai Lin
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Fujian, China
| | - Sang-Min Jeon
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul, Korea
- College of Pharmacy, Ajou University, Suwon, Gyeonggi-do, Korea
- Department of BioHealth Regulatory Science, Graduate School of Ajou University, Suwon, Gyeonggi-do, Korea
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Yuan R, Hahn Y, Stempel MH, Sidibe DK, Laxton O, Chen J, Kulkarni A, Maday S. Proteasomal inhibition preferentially stimulates lysosome activity relative to autophagic flux in primary astrocytes. Autophagy 2023; 19:570-596. [PMID: 35722992 PMCID: PMC9851260 DOI: 10.1080/15548627.2022.2084884] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 01/22/2023] Open
Abstract
Neurons and astrocytes face unique demands on their proteome to enable proper function and survival of the nervous system. Consequently, both cell types are critically dependent on robust quality control pathways such as macroautophagy (hereafter referred to as autophagy) and the ubiquitin-proteasome system (UPS). We previously reported that autophagy is differentially regulated in astrocytes and neurons in the context of metabolic stress, but less is understood in the context of proteotoxic stress induced by inhibition of the UPS. Dysfunction of the proteasome or autophagy has been linked to the progression of various neurodegenerative diseases. Therefore, in this study, we explored the connection between autophagy and the proteasome in primary astrocytes and neurons. Prior studies largely in non-neural models report a compensatory relationship whereby inhibition of the UPS stimulates autophagy. To our surprise, inhibition of the proteasome did not robustly upregulate autophagy in astrocytes or neurons. In fact, the effects on autophagy are modest particularly in comparison to paradigms of metabolic stress. Rather, we find that UPS inhibition in astrocytes induces formation of Ub-positive aggregates that harbor the selective autophagy receptor, SQSTM1/p62, but these structures were not productive substrates for autophagy. By contrast, we observed a significant increase in lysosomal degradation in astrocytes in response to UPS inhibition, but this stimulation was not sufficient to reduce total SQSTM1 levels. Last, UPS inhibition was more toxic in neurons compared to astrocytes, suggesting a cell type-specific vulnerability to proteotoxic stress.Abbreviations: Baf A1: bafilomycin A1; CQ: chloroquine; Epox: epoxomicin; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; p-ULK1: phospho-ULK1; SQSTM1/p62: sequestosome 1; Ub: ubiquitin; ULK1: unc-51 like kinase 1; UPS: ubiquitin-proteasome system.
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Affiliation(s)
- Ruiyi Yuan
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Younghee Hahn
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Max H. Stempel
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - David K. Sidibe
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Olivia Laxton
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Jessica Chen
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Aditi Kulkarni
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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3
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Xu H, Bensalel J, Raju S, Capobianco E, Lu ML, Wei J. Characterization of huntingtin interactomes and their dynamic responses in living cells by proximity proteomics. J Neurochem 2023; 164:512-528. [PMID: 36437609 DOI: 10.1111/jnc.15726] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 10/28/2022] [Accepted: 11/10/2022] [Indexed: 11/29/2022]
Abstract
Huntingtin (Htt) is a large protein without clearly defined molecular functions. Mutation in this protein causes Huntington's disease (HD), a fatal inherited neurodegenerative disorder. Identification of Htt-interacting proteins by the traditional approaches including yeast two-hybrid systems and affinity purifications has greatly facilitated the understanding of Htt function. However, these methods eliminated the intracellular spatial information of the Htt interactome during sample preparations. Moreover, the temporal changes of the Htt interactome in response to acute cellular stresses cannot be easily resolved with these approaches. Ascorbate peroxidase (APEX2)-based proximity labeling has been used to spatiotemporally investigate protein-protein interactions in living cells. In this study, we generated stable human SH-SY5Y cell lines expressing full-length Htt23Q and Htt145Q with N-terminus tagged Flag-APEX2 to quantitatively map the spatiotemporal changes of Htt interactome to a mild acute proteotoxic stress. Our data revealed that normal and mutant Htt (muHtt) are associated with distinct intracellular microenvironments. Specifically, mutant Htt is preferentially associated with intermediate filaments and myosin complexes. Furthermore, the dynamic changes of Htt interactomes in response to stress are different between normal and mutant Htt. Vimentin is identified as one of the most significant proteins that preferentially interacts with muHtt in situ. Further functional studies demonstrated that mutant Htt affects the vimentin's function of regulating proteostasis in healthy and HD human neural stem cells. Taken together, our data offer important insights into the molecular functions of normal and mutant Htt by providing a list of Htt-interacting proteins in their natural cellular context for further studies in different HD models.
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Affiliation(s)
- Hongyuan Xu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | - Johanna Bensalel
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | - Sunil Raju
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | | | - Michael L Lu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | - Jianning Wei
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
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Zhang J, Lin X, Chen Y, Li T, Lee AC, Chow EY, Cho WC, Chan T. LAFITE Reveals the Complexity of Transcript Isoforms in Subcellular Fractions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2203480. [PMID: 36461702 PMCID: PMC9875686 DOI: 10.1002/advs.202203480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Characterization of the subcellular distribution of RNA is essential for understanding the molecular basis of biological processes. Here, the subcellular nanopore direct RNA-sequencing (DRS) of four lung cancer cell lines (A549, H1975, H358, and HCC4006) is performed, coupled with a computational pipeline, Low-abundance Aware Full-length Isoform clusTEr (LAFITE), to comprehensively analyze the full-length cytoplasmic and nuclear transcriptome. Using additional DRS and orthogonal data sets, it is shown that LAFITE outperforms current methods for detecting full-length transcripts, particularly for low-abundance isoforms that are usually overlooked due to poor read coverage. Experimental validation of six novel isoforms exclusively identified by LAFITE further confirms the reliability of this pipeline. By applying LAFITE to subcellular DRS data, the complexity of the nuclear transcriptome is revealed in terms of isoform diversity, 3'-UTR usage, m6A modification patterns, and intron retention. Overall, LAFITE provides enhanced full-length isoform identification and enables a high-resolution view of the RNA landscape at the isoform level.
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Affiliation(s)
- Jizhou Zhang
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Xiao Lin
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Yuelong Chen
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Tsz‐Ho Li
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Alan Chun‐Kit Lee
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
| | | | | | - Ting‐Fung Chan
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
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Kumar AV, Mills J, Lapierre LR. Selective Autophagy Receptor p62/SQSTM1, a Pivotal Player in Stress and Aging. Front Cell Dev Biol 2022; 10:793328. [PMID: 35237597 PMCID: PMC8883344 DOI: 10.3389/fcell.2022.793328] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/19/2022] [Indexed: 12/29/2022] Open
Abstract
Efficient proteostasis is crucial for somatic maintenance, and its decline during aging leads to cellular dysfunction and disease. Selective autophagy is a form of autophagy mediated by receptors that target specific cargoes for degradation and is an essential process to maintain proteostasis. The protein Sequestosome 1 (p62/SQSTM1) is a classical selective autophagy receptor, but it also has roles in the ubiquitin-proteasome system, cellular metabolism, signaling, and apoptosis. p62 is best known for its role in clearing protein aggregates via aggrephagy, but it has recently emerged as a receptor for other forms of selective autophagy such as mitophagy and lipophagy. Notably, p62 has context-dependent impacts on organismal aging and turnover of p62 usually reflects active proteostasis. In this review, we highlight recent advances in understanding the role of p62 in coordinating the ubiquitin-proteasome system and autophagy. We also discuss positive and negative effects of p62 on proteostatic status and their implications on aging and neurodegeneration. Finally, we relate the link between defective p62 and diseases of aging and examine the utility of targeting this multifaceted protein to achieve proteostatic benefits.
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Affiliation(s)
| | | | - Louis R. Lapierre
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, United States
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Elzek MAW, Christopher JA, Breckels LM, Lilley KS. Localization of Organelle Proteins by Isotope Tagging: Current status and potential applications in drug discovery research. DRUG DISCOVERY TODAY. TECHNOLOGIES 2021; 39:57-67. [PMID: 34906326 DOI: 10.1016/j.ddtec.2021.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/26/2021] [Accepted: 06/11/2021] [Indexed: 12/18/2022]
Abstract
Spatial proteomics has provided important insights into the relationship between protein function and subcellular location. Localization of Organelle Proteins by Isotope Tagging (LOPIT) and its variants are proteome-wide techniques, not matched in scale by microscopy-based or proximity tagging-based techniques, allowing holistic mapping of protein subcellular location and re-localization events downstream of cellular perturbations. LOPIT can be a powerful and versatile tool in drug discovery for unlocking important information on disease pathophysiology, drug mechanism of action, and off-target toxicity screenings. Here, we discuss technical concepts of LOPIT with its potential applications in drug discovery and development research.
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Affiliation(s)
- Mohamed A W Elzek
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge, CB2 0AW, United Kingdom
| | - Josie A Christopher
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge, CB2 0AW, United Kingdom
| | - Lisa M Breckels
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge, CB2 0AW, United Kingdom
| | - Kathryn S Lilley
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge, CB2 0AW, United Kingdom.
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7
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Macroautophagy and Mitophagy in Neurodegenerative Disorders: Focus on Therapeutic Interventions. Biomedicines 2021; 9:biomedicines9111625. [PMID: 34829854 PMCID: PMC8615936 DOI: 10.3390/biomedicines9111625] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 02/06/2023] Open
Abstract
Macroautophagy, a quality control mechanism, is an evolutionarily conserved pathway of lysosomal degradation of protein aggregates, pathogens, and damaged organelles. As part of its vital homeostatic role, macroautophagy deregulation is associated with various human disorders, including neurodegenerative diseases. There are several lines of evidence that associate protein misfolding and mitochondrial dysfunction in the etiology of Alzheimer’s, Parkinson’s, and Huntington’s diseases. Macroautophagy has been implicated in the degradation of different protein aggregates such as Aβ, tau, alpha-synuclein (α-syn), and mutant huntingtin (mHtt) and in the clearance of dysfunctional mitochondria. Taking these into consideration, targeting autophagy might represent an effective therapeutic strategy to eliminate protein aggregates and to improve mitochondrial function in these disorders. The present review describes our current understanding on the role of macroautophagy in neurodegenerative disorders and focuses on possible strategies for its therapeutic modulation.
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8
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The Role of Autophagy in Anti-Cancer and Health Promoting Effects of Cordycepin. Molecules 2021; 26:molecules26164954. [PMID: 34443541 PMCID: PMC8400201 DOI: 10.3390/molecules26164954] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 12/18/2022] Open
Abstract
Cordycepin is an adenosine derivative isolated from Cordyceps sinensis, which has been used as an herbal complementary and alternative medicine with various biological activities. The general anti-cancer mechanisms of cordycepin are regulated by the adenosine A3 receptor, epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (MAPKs), and glycogen synthase kinase (GSK)-3β, leading to cell cycle arrest or apoptosis. Notably, cordycepin also induces autophagy to trigger cell death, inhibits tumor metastasis, and modulates the immune system. Since the dysregulation of autophagy is associated with cancers and neuron, immune, and kidney diseases, cordycepin is considered an alternative treatment because of the involvement of cordycepin in autophagic signaling. However, the profound mechanism of autophagy induction by cordycepin has never been reviewed in detail. Therefore, in this article, we reviewed the anti-cancer and health-promoting effects of cordycepin in the neurons, kidneys, and the immune system through diverse mechanisms, including autophagy induction. We also suggest that formulation changes for cordycepin could enhance its bioactivity and bioavailability and lower its toxicity for future applications. A comprehensive understanding of the autophagy mechanism would provide novel mechanistic insight into the anti-cancer and health-promoting effects of cordycepin.
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Xu H, Bensalel J, Capobianco E, Lu ML, Wei J. Impaired Restoration of Global Protein Synthesis Contributes to Increased Vulnerability to Acute ER Stress Recovery in Huntington's Disease. Cell Mol Neurobiol 2021; 42:2757-2771. [PMID: 34347195 DOI: 10.1007/s10571-021-01137-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/28/2021] [Indexed: 12/21/2022]
Abstract
Neurons are susceptible to different cellular stresses and this vulnerability has been implicated in the pathogenesis of Huntington's disease (HD). Accumulating evidence suggest that acute or chronic stress, depending on its duration and severity, can cause irreversible cellular damages to HD neurons, which contributes to neurodegeneration. In contrast, how normal and HD neurons respond during the resolution of a cellular stress remain less explored. In this study, we challenged normal and HD cells with a low-level acute ER stress and examined the molecular and cellular responses after stress removal. Using both striatal cell lines and primary neurons, we first showed the temporal activation of p-eIF2α-ATF4-GADD34 pathway in response to the acute ER stress and during recovery between normal and HD cells. HD cells were more vulnerable to cell death during stress recovery and were associated with increased number of apoptotic/necrotic cells and decreased cell proliferation. This is also supported by the Gene Ontology analysis from the RNA-seq data which indicated that "apoptosis-related Biological Processes" were more enriched in HD cells during stress recovery. We further showed that HD cells were defective in restoring global protein synthesis during stress recovery and promoting protein synthesis by an integrated stress response inhibitor, ISRIB, could attenuate cell death in HD cells. Together, these data suggest that normal and HD cells undergo distinct mechanisms of transcriptional reprogramming, leading to different cell fate decisions during the stress recovery.
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Affiliation(s)
- Hongyuan Xu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Johanna Bensalel
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Enrico Capobianco
- Institute of Data Science and Computing, University of Miami, Miami, FL, 33146, USA
| | - Michael L Lu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Jianning Wei
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA.
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10
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Bensalel J, Xu H, Lu ML, Capobianco E, Wei J. RNA-seq analysis reveals significant transcriptome changes in huntingtin-null human neuroblastoma cells. BMC Med Genomics 2021; 14:176. [PMID: 34215255 PMCID: PMC8252266 DOI: 10.1186/s12920-021-01022-w] [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: 05/22/2020] [Accepted: 06/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Huntingtin (Htt) protein is the product of the gene mutated in Huntington's disease (HD), a fatal, autosomal dominant, neurodegenerative disorder. Normal Htt is essential for early embryogenesis and the development of the central nervous system. However, the role of Htt in adult tissues is less defined. Following the recent promising clinical trial in which both normal and mutant Htt mRNA were knocked down in HD patients, there is an urgent need to fully understand the molecular consequences of knocking out/down Htt in adult tissues. Htt has been identified as an important transcriptional regulator. Unbiased investigations of transcriptome changes with RNA-sequencing (RNA-Seq) have been done in multiple cell types in HD, further confirming that transcriptional dysregulation is a central pathogenic mechanism in HD. However, there is lack of direct understanding of the transcriptional regulation by normal Htt. METHODS To investigate the transcriptional role of normal Htt, we first knocked out Htt in the human neuroblastoma SH-SY5Y cell line using the CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 (CRISPR-associated protein 9) gene editing approach. We then performed RNA-seq analysis on Htt-null and wild type SH-SY5Y cells to probe the global transcriptome changes induced by Htt deletion. RESULTS In general, Htt has a widespread effect on gene transcription. Functional analysis of the differentially expressed genes (DEGs) using various bioinformatic tools revealed irregularities in pathways related to cell communication and signaling, and more specifically those related to neuron development, neurotransmission and synaptic signaling. We further examined the transcription factors that may regulate these DEGs. Consistent with the disrupted pathways associated with cellular development, we showed that Htt-null cells exhibited slower cell proliferation than wild type cells. We finally validated some of the top DEGS with quantitative RT-PCR. CONCLUSIONS The widespread transcriptome changes in Htt-null cells could be directly caused by the loss of Htt-mediated transcriptional regulation or due to the secondary consequences of disruption in the gene regulatory network. Our study therefore provides valuable information about key genes associated with Htt-mediated transcription and improves our understanding of the molecular mechanisms underlying the cellular functions of normal and mutant Htt.
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Affiliation(s)
- Johanna Bensalel
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Hongyuan Xu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Michael L Lu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Enrico Capobianco
- Institute of Data Science and Computing, University of Miami, Miami, FL, 33146, USA
| | - Jianning Wei
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA.
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11
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Galpayage Dona KNU, Du E, Wei J. An impedimetric assay for the identification of abnormal mitochondrial dynamics in living cells. Electrophoresis 2020; 42:163-170. [PMID: 33169407 DOI: 10.1002/elps.202000125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 01/16/2023]
Abstract
Mitochondrial dynamics (fission and fusion) plays an important role in cell functions. Disruption in mitochondrial dynamics has been associated with diseases such as neurobiological disorders and cardiovascular diseases. Analysis of mitochondrial fission/fusion has been mostly achieved through direct visualization of the fission/fusion events in live-cell imaging of fluorescently labeled mitochondria. In this study, we demonstrated a label-free, non-invasive Electrical Impedance Spectroscopy (EIS) approach to analyze mitochondrial dynamics in a genetically modified human neuroblastoma SH-SY5Y cell line with no huntingtin protein expression. Huntingtin protein has been shown to regulate mitochondria dynamics. We performed EIS studies on normal SH-SY5Y cells and two independent clones of huntingtin-null cells. The impedance data was used to determine the suspension conductivity and further cytoplasmic conductivity and relate to the abnormal mitochondrial dynamics. For instance, the cytoplasm conductivity value was increased by 11% from huntingtin-null cells to normal cells. Results of this study demonstrated that EIS is sensitive to characterize the abnormal mitochondrial dynamics that can be difficult to quantify by the conventional microscopic method.
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Affiliation(s)
| | - E Du
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida, USA
| | - Jianning Wei
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
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12
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Hu S, Chen L, Al Mamun A, Ni L, Gao W, Lin Y, Jin H, Zhang X, Wang X. The therapeutic effect of TBK1 in intervertebral disc degeneration via coordinating selective autophagy and autophagic functions. J Adv Res 2020; 30:1-13. [PMID: 34026282 PMCID: PMC8132185 DOI: 10.1016/j.jare.2020.08.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/17/2022] Open
Abstract
Introduction While its innate immune function has been known, recent works of literature have focused on the role of Tank binding kinase 1 (TBK1) in regulating autophagy and it is unknown whether TBK1 protects against intervertebral disc degeneration (IVDD) through affecting autophagy. Objectives Here, we aim to explore whether TBK1 is implicated in the pathogenesis of IVDD, and investigated the potential mechanism. Methods Western blotting and immunohistochemistry were used to detect the TBK1 expression in human and rat NP tissue. After TBK1 overexpression in NP cells with lentivirus transfection, autophagic flux, apoptosis and senescence percentage were assessed. Si-RNA , a utophagy inhibitors and protein phosphatase inhibitors were applied to study the mechanism of autophagy regulation. In vivo study, we further evaluated the therapeutic action of lentivirus-TBK1(Lv-TBK1)injection in a rodent IVDD model. Results The TBK1 level was reduced in rat and human NP tissue. TBK1 overexpression protected against apoptosis and premature senescence. These functions of TBK1 were abolished by chloroquine-medicated autophagy inhibition.P-TBK1, an activation form of TBK, is involved in selective autophagy through directly phosphorylating P62 at Ser 403, and the activation of TBK1 is also dependent on Parkin manner. TBK1 also activated NPCs autophagy to relieve puncture injury in vivo. Conclusion We demonstrated that TBK1 overexpression attenuated senescence and apoptosis and promoted NPCs survival via upregulating autophagy. TBK1 represents a promising avenue for IVDD treatment.
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Affiliation(s)
- Sunli Hu
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China.,Key Laboratory of Orthopaedics of Zhejiang Province, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University , Wenzhou, Zhejiang Province, China
| | - Liang Chen
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China.,Key Laboratory of Orthopaedics of Zhejiang Province, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University , Wenzhou, Zhejiang Province, China
| | - Abdullah Al Mamun
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang Province, China
| | - Libin Ni
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China.,Key Laboratory of Orthopaedics of Zhejiang Province, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University , Wenzhou, Zhejiang Province, China
| | - Weiyang Gao
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China
| | - Yan Lin
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China
| | - Haiming Jin
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China
| | - Xiaolei Zhang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China.,Key Laboratory of Orthopaedics of Zhejiang Province, Wenzhou, Zhejiang Province, China
| | - Xiangyang Wang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou 325027, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University , Wenzhou, Zhejiang Province, China
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13
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Lontay B, Kiss A, Virág L, Tar K. How Do Post-Translational Modifications Influence the Pathomechanistic Landscape of Huntington's Disease? A Comprehensive Review. Int J Mol Sci 2020; 21:ijms21124282. [PMID: 32560122 PMCID: PMC7349273 DOI: 10.3390/ijms21124282] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 12/15/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant inherited neurodegenerative disorder characterized by the loss of motor control and cognitive ability, which eventually leads to death. The mutant huntingtin protein (HTT) exhibits an expansion of a polyglutamine repeat. The mechanism of pathogenesis is still not fully characterized; however, evidence suggests that post-translational modifications (PTMs) of HTT and upstream and downstream proteins of neuronal signaling pathways are involved. The determination and characterization of PTMs are essential to understand the mechanisms at work in HD, to define possible therapeutic targets better, and to challenge the scientific community to develop new approaches and methods. The discovery and characterization of a panoply of PTMs in HTT aggregation and cellular events in HD will bring us closer to understanding how the expression of mutant polyglutamine-containing HTT affects cellular homeostasis that leads to the perturbation of cell functions, neurotoxicity, and finally, cell death. Hence, here we review the current knowledge on recently identified PTMs of HD-related proteins and their pathophysiological relevance in the formation of abnormal protein aggregates, proteolytic dysfunction, and alterations of mitochondrial and metabolic pathways, neuroinflammatory regulation, excitotoxicity, and abnormal regulation of gene expression.
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Affiliation(s)
- Beata Lontay
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
| | - Andrea Kiss
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
| | - László Virág
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Krisztina Tar
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
- Correspondence: ; Tel.: +36-52-412345
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14
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Kacher R, Lamazière A, Heck N, Kappes V, Mounier C, Despres G, Dembitskaya Y, Perrin E, Christaller W, Sasidharan Nair S, Messent V, Cartier N, Vanhoutte P, Venance L, Saudou F, Néri C, Caboche J, Betuing S. CYP46A1 gene therapy deciphers the role of brain cholesterol metabolism in Huntington's disease. Brain 2020; 142:2432-2450. [PMID: 31286142 DOI: 10.1093/brain/awz174] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 04/08/2019] [Accepted: 04/23/2019] [Indexed: 11/14/2022] Open
Abstract
Dysfunctions in brain cholesterol homeostasis have been extensively related to brain disorders. The main pathway for brain cholesterol elimination is its hydroxylation into 24S-hydroxycholesterol by the cholesterol 24-hydrolase, CYP46A1. Increasing evidence suggests that CYP46A1 has a role in the pathogenesis and progression of neurodegenerative disorders, and that increasing its levels in the brain is neuroprotective. However, the mechanisms underlying this neuroprotection remain to be fully understood. Huntington's disease is a fatal autosomal dominant neurodegenerative disease caused by an abnormal CAG expansion in huntingtin's gene. Among the multiple cellular and molecular dysfunctions caused by this mutation, altered brain cholesterol homeostasis has been described in patients and animal models as a critical event in Huntington's disease. Here, we demonstrate that a gene therapy approach based on the delivery of CYP46A1, the rate-limiting enzyme for cholesterol degradation in the brain, has a long-lasting neuroprotective effect in Huntington's disease and counteracts multiple detrimental effects of the mutated huntingtin. In zQ175 Huntington's disease knock-in mice, CYP46A1 prevented neuronal dysfunctions and restored cholesterol homeostasis. These events were associated to a specific striatal transcriptomic signature that compensates for multiple mHTT-induced dysfunctions. We thus explored the mechanisms for these compensations and showed an improvement of synaptic activity and connectivity along with the stimulation of the proteasome and autophagy machineries, which participate to the clearance of mutant huntingtin (mHTT) aggregates. Furthermore, BDNF vesicle axonal transport and TrkB endosome trafficking were restored in a cellular model of Huntington's disease. These results highlight the large-scale beneficial effect of restoring cholesterol homeostasis in neurodegenerative diseases and give new opportunities for developing innovative disease-modifying strategies in Huntington's disease.
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Affiliation(s)
- Radhia Kacher
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
| | - Antonin Lamazière
- LBM, CNRS UMR7203/INSERM U1157, Sorbonne Université, Faculté de Médecine, AP-HP, Hôpital Saint Antoine, Département PM2, Paris, France
| | - Nicolas Heck
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
| | - Vincent Kappes
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
| | - Coline Mounier
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
| | - Gaëtan Despres
- LBM, CNRS UMR7203/INSERM U1157, Sorbonne Université, Faculté de Médecine, AP-HP, Hôpital Saint Antoine, Département PM2, Paris, France
| | - Yulia Dembitskaya
- Center for Interdisciplinary Research in Biology, College de France, CNRS UMR7241/INSERM U1050, MemoLife Labex Paris, France
| | - Elodie Perrin
- Center for Interdisciplinary Research in Biology, College de France, CNRS UMR7241/INSERM U1050, MemoLife Labex Paris, France
| | - Wilhelm Christaller
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, INSERM U1216, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Satish Sasidharan Nair
- Sorbonne Université, Centre National de la Recherche Scientifique, Research Unit Biology of Adaptation and Aging (B2A), Team Compensation in Neurodegenerative and Aging (Brain-C), F-75252, Paris, France
| | - Valérie Messent
- Neuroplasticity of Reproductive Behaviors, Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine, Institut de Biologie Paris Seine, Faculté des Sciences et Ingénierie, INSERM/UMR-S 1130, CNRS/UMR 8246, 75005 Paris, France
| | - Nathalie Cartier
- Biotherapies for neurodegenerative diseases, Institut du Cerveau et de la Moelle (ICM) INSERM Sorbonne Université, Paris, France
| | - Peter Vanhoutte
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
| | - Laurent Venance
- Center for Interdisciplinary Research in Biology, College de France, CNRS UMR7241/INSERM U1050, MemoLife Labex Paris, France
| | - Frédéric Saudou
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, INSERM U1216, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Christian Néri
- Sorbonne Université, Centre National de la Recherche Scientifique, Research Unit Biology of Adaptation and Aging (B2A), Team Compensation in Neurodegenerative and Aging (Brain-C), F-75252, Paris, France
| | - Jocelyne Caboche
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
| | - Sandrine Betuing
- Neuroscience Paris Seine, Institut de Biologie Paris-Seine, CNRS UMR 8246/INSERM U1130., Sorbonne Université, Paris, France
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15
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Jevtic SD, Provias JP. Case report and literature review of Huntington disease with intermediate CAG expansion. BMJ Neurol Open 2020; 2:e000027. [PMID: 33681777 PMCID: PMC7871728 DOI: 10.1136/bmjno-2019-000027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2020] [Indexed: 01/08/2023] Open
Abstract
Background Huntington disease (HD) is a genetically inherited neurodegenerative disorder that classically involves a trinucleotide CAG repeat expansion on chromosome 4, with 36 repeats or greater being disease identifying. It generally presents between the age of 30 and 40 years old and is characterised by severe caudate/striatum degeneration with huntingtin protein aggregation. We present here the case of a patient in her early 80s who presented with 5-year history of worsening chorea and family history of HD but an intermediate length CAG expansion. Methods Genetic testing of CAG repeats on chromosome 4. Postmortem brain tissue was obtained and stained using immunohistochemistry for amyloid-beta, tau and glial fibrillary acidic protein (GFAP). Sections from the caudate/putamen were also analysed by p62 immunofluorescence. All sections were reviewed by trained neuropathologists. Results On genetic testing the patient was found to have a 28 CAG repeat on the longest expansion. Microscopic analysis revealed significant neuronal atrophy in the caudate and putamen with gliosis. Immunofluorescent staining demonstrated minimal intranuclear p62 inclusions suggesting little huntingtin aggregation present. Furthermore, there was significant amyloid-beta pathology (Thal-IV stage) and tau involvement in the medial temporal lobe (Braak stage II). Conclusion This case provides clinical and pathological evidence to support an emerging clinical entity involving HD presentation in late age with an intermediate CAG repeat.
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Affiliation(s)
- Stefan D Jevtic
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - John P Provias
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada.,Laboratory Medicine and Pathology - Neuropathology, Hamilton Health Sciences, Hamilton, Ontario, Canada
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16
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Valionyte E, Yang Y, Roberts SL, Kelly J, Lu B, Luo S. Lowering Mutant Huntingtin Levels and Toxicity: Autophagy-Endolysosome Pathways in Huntington's Disease. J Mol Biol 2019; 432:2673-2691. [PMID: 31786267 DOI: 10.1016/j.jmb.2019.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/04/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023]
Abstract
Huntington's disease (HD) is a monogenetic neurodegenerative disease, which serves as a model of neurodegeneration with protein aggregation. Autophagy has been suggested to possess a great value to tackle protein aggregation toxicity and neurodegenerative diseases. Current studies suggest that autophagy-endolysosomal pathways are critical for HD pathology. Here we review recent advancement in the studies of autophagy and selective autophagy relating HD. Restoration of autophagy flux and enhancement of selective removal of mutant huntingtin/disease-causing protein would be effective approaches towards tackling HD as well as other similar neurodegenerative disorders.
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Affiliation(s)
- Evelina Valionyte
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Yi Yang
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Sheridan L Roberts
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Jack Kelly
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Boxun Lu
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Shouqing Luo
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK.
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17
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Ma S, Attarwala IY, Xie XQ. SQSTM1/p62: A Potential Target for Neurodegenerative Disease. ACS Chem Neurosci 2019; 10:2094-2114. [PMID: 30657305 DOI: 10.1021/acschemneuro.8b00516] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases, characterized by a progressive loss of brain function, affect the lives of millions of individuals worldwide. The complexity of the brain poses a challenge for scientists trying to map the biochemical and physiological pathways to identify areas of pathological errors. Brain samples of patients with neurodegenerative diseases have been shown to contain large amounts of misfolded and abnormally aggregated proteins, resulting in dysfunction in certain brain centers. Removal of these abnormal molecules is essential in maintaining protein homeostasis and overall neuronal health. Macroautophagy is a major route by which cells achieve this. Administration of certain autophagy-enhancing compounds has been shown to provide therapeutic effects for individuals with neurodegenerative conditions. SQSTM1/p62 is a scaffold protein closely involved in the macroautophagy process. p62 functions to anchor the ubiquitinated proteins to the autophagosome membrane, promoting degradation of unwanted molecules. Modulators targeting p62 to induce autophagy and promote its protective pathways for aggregate protein clearance have high potential in the treatment of these conditions. Additionally, causal relationships have been found between errors in regulation of SQSTM1/p62 and the development of a variety of neurodegenerative disorders, including Alzheimer's, Parkinson's, Huntington's, amyotrophic lateral sclerosis, and frontotemporal lobar degeneration. Furthermore, SQSTM1/p62 also serves as a signaling hub for multiple pathways associated with neurodegeneration, providing a potential therapeutic target in the treatment of neurodegenerative diseases. However, rational design of a p62-oriented autophagy modulator that can balance the negative and positive functions of multiple domains in p62 requires further efforts in the exploration of the protein structure and pathological basis.
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Affiliation(s)
| | | | - Xiang-Qun Xie
- ID4Pharma LLC, Bridgeville, Pennsylvania 15017, United States
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18
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Dysregulation of bcl-2 enhanced rotenone-induced α-synuclein aggregation associated with autophagic pathways. Neuroreport 2019; 29:1201-1208. [PMID: 30059366 DOI: 10.1097/wnr.0000000000001097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
α-Synuclein (α-syn) aggregation has far-reaching implications in the pathogenesis of Parkinson's disease, and the levels of α-syn protein determine its neurotoxic potential. However, the intrinsic pathway of α-syn accumulation and the mode of α-syn degradation remain contentious. Following a stereotactic infusion of rotenone into the substantia nigra and the ventral tegmental area, the chronic rat model of Parkinson's disease was established successfully. In response to the rotenone, increased intracellular α-syn levels and autophagic flux monitored by LC3 II turnover were induced in dopaminergic neurons (TH-positive) of rat substantia nigra and ventral tegmental area. In the cytoplasm, increased immune response of LC3 colocalized with α-syn on the basis of rotenone-mediated neurotoxicity. The immunoreactivity for p62, an adaptor of the autophagy, was upregulated in the cytoplasm and nucleus. The enhancement of autophagy by valproate acid decreased rotenone-induced α-syn aggregation, whereas the inhibition of autophagy by 3-methyladenine increased α-syn aggregation. In addition, the expression of bcl-2 was reduced in rotenone-induced neurotoxicity, accompanied by the enhancement of autophagy. Small interfering RNA-mediated knockdown of bcl-2 expression facilitated the expression of p62 protein and autophagy. Moreover, the inhibition of bcl-2 increased rotenone-based α-syn aggregation. In short, in rotenone-based models, dowregulation of bcl-2 negatively controlled rotenone-induced autophagy and α-syn aggregation.
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19
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Sánchez-Martín P, Komatsu M. p62/SQSTM1 - steering the cell through health and disease. J Cell Sci 2018; 131:131/21/jcs222836. [PMID: 30397181 DOI: 10.1242/jcs.222836] [Citation(s) in RCA: 187] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SQSTM1 (also known as p62) is a multifunctional stress-inducible scaffold protein involved in diverse cellular processes. Its functions are tightly regulated through an extensive pattern of post-translational modifications, and include the isolation of cargos degraded by autophagy, induction of the antioxidant response by the Keap1-Nrf2 system, as well as the regulation of endosomal trafficking, apoptosis and inflammation. Accordingly, malfunction of SQSTM1 is associated with a wide range of diseases, including bone and muscle disorders, neurodegenerative and metabolic diseases, and multiple forms of cancer. In this Review, we summarize current knowledge regarding regulation, post-translational modifications and functions of SQSTM1, as well as how they are dysregulated in various pathogenic contexts.
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Affiliation(s)
- Pablo Sánchez-Martín
- Department of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata 951-8510, Japan
| | - Masaaki Komatsu
- Department of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata 951-8510, Japan .,Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
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