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Jiang J, Zhang L, Zou J, Liu J, Yang J, Jiang Q, Duan P, Jiang B. Phosphorylated S6K1 and 4E-BP1 play different roles in constitutively active Rheb-mediated retinal ganglion cell survival and axon regeneration after optic nerve injury. Neural Regen Res 2023; 18:2526-2534. [PMID: 37282486 PMCID: PMC10360084 DOI: 10.4103/1673-5374.371372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Ras homolog enriched in brain (Rheb) is a small GTPase that activates mammalian target of rapamycin complex 1 (mTORC1). Previous studies have shown that constitutively active Rheb can enhance the regeneration of sensory axons after spinal cord injury by activating downstream effectors of mTOR. S6K1 and 4E-BP1 are important downstream effectors of mTORC1. In this study, we investigated the role of Rheb/mTOR and its downstream effectors S6K1 and 4E-BP1 in the protection of retinal ganglion cells. We transfected an optic nerve crush mouse model with adeno-associated viral 2-mediated constitutively active Rheb and observed the effects on retinal ganglion cell survival and axon regeneration. We found that overexpression of constitutively active Rheb promoted survival of retinal ganglion cells in the acute (14 days) and chronic (21 and 42 days) stages of injury. We also found that either co-expression of the dominant-negative S6K1 mutant or the constitutively active 4E-BP1 mutant together with constitutively active Rheb markedly inhibited axon regeneration of retinal ganglion cells. This suggests that mTORC1-mediated S6K1 activation and 4E-BP1 inhibition were necessary components for constitutively active Rheb-induced axon regeneration. However, only S6K1 activation, but not 4E-BP1 knockdown, induced axon regeneration when applied alone. Furthermore, S6K1 activation promoted the survival of retinal ganglion cells at 14 days post-injury, whereas 4E-BP1 knockdown unexpectedly slightly decreased the survival of retinal ganglion cells at 14 days post-injury. Overexpression of constitutively active 4E-BP1 increased the survival of retinal ganglion cells at 14 days post-injury. Likewise, co-expressing constitutively active Rheb and constitutively active 4E-BP1 markedly increased the survival of retinal ganglion cells compared with overexpression of constitutively active Rheb alone at 14 days post-injury. These findings indicate that functional 4E-BP1 and S6K1 are neuroprotective and that 4E-BP1 may exert protective effects through a pathway at least partially independent of Rheb/mTOR. Together, our results show that constitutively active Rheb promotes the survival of retinal ganglion cells and axon regeneration through modulating S6K1 and 4E-BP1 activity. Phosphorylated S6K1 and 4E-BP1 promote axon regeneration but play an antagonistic role in the survival of retinal ganglion cells.
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Affiliation(s)
- Jikuan Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Lusi Zhang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jingling Zou
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jingyuan Liu
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jia Yang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Qian Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Peiyun Duan
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Bing Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
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Kubat Oktem E, Aydin B, Yazar M, Arga KY. Integrative Analysis of Motor Neuron and Microglial Transcriptomes from SOD1 G93A Mice Models Uncover Potential Drug Treatments for ALS. J Mol Neurosci 2022; 72:2360-2376. [PMID: 36178612 DOI: 10.1007/s12031-022-02071-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 09/19/2022] [Indexed: 02/07/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease of motor neurons that mainly affects the motor cortex, brainstem, and spinal cord. Under disease conditions, microglia could possess two distinct profiles, M1 (toxic) and M2 (protective), with the M2 profile observed at disease onset. SOD1 (superoxide dismutase 1) gene mutations account for up to 20% of familial ALS cases. Comparative gene expression differences in M2-protective (early) stage SOD1G93A microglia and age-matched SOD1G93A motor neurons are poorly understood. We evaluated the differential gene expression profiles in SOD1G93A microglia and SOD1G93A motor neurons utilizing publicly available transcriptomics data and bioinformatics analyses, constructed biomolecular networks around them, and identified gene clusters as potential drug targets. Following a drug repositioning strategy, 5 small compounds (belinostat, auranofin, BRD-K78930611, AZD-8055, and COT-10b) were repositioned as potential ALS therapeutic candidates that mimic the protective state of microglia and reverse the toxic state of motor neurons. We anticipate that this study will provide new insights into the ALS pathophysiology linking the M2 state of microglia and drug repositioning.
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Affiliation(s)
- Elif Kubat Oktem
- Department of Molecular Biology and Genetics, Faculty of Engineering and Natural Sciences, Istanbul Medeniyet University, Kuzey Yerleşkesi H Blok, Ünalan Sk. D100 Karayolu Yanyol 34700, Istanbul, Turkey.
| | - Busra Aydin
- Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, Konya, Turkey
| | - Metin Yazar
- Department of Genetics and Bioengineering, Faculty of Engineering and Natural Sciences, Istanbul Okan University, Istanbul, Turkey.,Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
| | - Kazim Yalcin Arga
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey.,Genetic and Metabolic Diseases Research and Investigation Center, Marmara University, Istanbul, Turkey
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Chaudhary S, Dhiman A, Dilawari R, Chaubey GK, Talukdar S, Modanwal R, Patidar A, Malhotra H, Raje CI, Raje M. Glyceraldehyde-3-Phosphate Dehydrogenase Facilitates Macroautophagic Degradation of Mutant Huntingtin Protein Aggregates. Mol Neurobiol 2021; 58:5790-5798. [PMID: 34406601 DOI: 10.1007/s12035-021-02532-5] [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: 04/01/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022]
Abstract
Protein aggregate accumulation is a pathological hallmark of several neurodegenerative disorders. Autophagy is critical for clearance of aggregate-prone proteins. In this study, we identify a novel role of the multifunctional glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in clearance of intracellular protein aggregates. Previously, it has been reported that though clearance of wild-type huntingtin protein is mediated by chaperone-mediated autophagy (CMA), however, degradation of mutant huntingtin (mHtt with numerous poly Q repeats) remains impaired by this route as mutant Htt binds with high affinity to Hsc70 and LAMP-2A. This delays delivery of misfolded protein to lysosomes and results in accumulation of intracellular aggregates which are degraded only by macroautophagy. Earlier investigations also suggest that mHtt causes inactivation of mTOR signaling, causing upregulation of autophagy. GAPDH had earlier been reported to interact with mHtt resulting in cellular toxicity. Utilizing a cell culture model of mHtt aggregates coupled with modulation of GAPDH expression, we analyzed the formation of intracellular aggregates and correlated this with autophagy induction. We observed that GAPDH knockdown cells transfected with N-terminal mutant huntingtin (103 poly Q residues) aggregate-prone protein exhibit diminished autophagy. GAPDH was found to regulate autophagy via the mTOR pathway. Significantly more and larger-sized huntingtin protein aggregates were observed in GAPDH knockdown cells compared to empty vector-transfected control cells. This correlated with the observed decrease in autophagy. Overexpression of GAPDH had a protective effect on cells resulting in a decreased load of aggregates. Our results demonstrate that GAPDH assists in the clearance of protein aggregates by autophagy induction. These findings provide a new insight in understanding the mechanism of mutant huntingtin aggregate clearance. By studying the molecular mechanism of protein aggregate clearance via GAPDH, we hope to provide a new approach in targeting and understanding several neurodegenerative disorders.
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Affiliation(s)
- Surbhi Chaudhary
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | - Asmita Dhiman
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | - Rahul Dilawari
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | | | - Sharmila Talukdar
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | - Radheshyam Modanwal
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | - Anil Patidar
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | - Himanshu Malhotra
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036
| | - Chaaya Iyengar Raje
- National Institute of Pharmaceutical Education & Research, Phase X, Sector 67, SAS Nagar, Punjab, India, 160062
| | - Manoj Raje
- Institute of Microbial Technology, CSIR, Sector 39A, Chandigarh, India, 160036.
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Nam Y, Moon GJ, Kim SR. Therapeutic Potential of AAV1-Rheb(S16H) Transduction against Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22063064. [PMID: 33802760 PMCID: PMC8002454 DOI: 10.3390/ijms22063064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/08/2021] [Accepted: 03/16/2021] [Indexed: 01/19/2023] Open
Abstract
Neurotrophic factors (NTFs) are essential for cell growth, survival, synaptic plasticity, and maintenance of specific neuronal population in the central nervous system. Multiple studies have demonstrated that alterations in the levels and activities of NTFs are related to the pathology and symptoms of neurodegenerative disorders, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), and Huntington’s disease. Hence, the key molecule that can regulate the expression of NTFs is an important target for gene therapy coupling adeno-associated virus vector (AAV) gene. We have previously reported that the Ras homolog protein enriched in brain (Rheb)–mammalian target of rapamycin complex 1 (mTORC1) axis plays a vital role in preventing neuronal death in the brain of AD and PD patients. AAV transduction using a constitutively active form of Rheb exerts a neuroprotective effect through the upregulation of NTFs, thereby promoting the neurotrophic interaction between astrocytes and neurons in AD conditions. These findings suggest the role of Rheb as an important regulator of the regulatory system of NTFs to treat neurodegenerative diseases. In this review, we present an overview of the role of Rheb in neurodegenerative diseases and summarize the therapeutic potential of AAV serotype 1 (AAV1)-Rheb(S16H) transduction in the treatment of neurodegenerative disorders, focusing on diseases, such as AD and PD.
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Affiliation(s)
- Youngpyo Nam
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41944, Korea;
| | - Gyeong Joon Moon
- Center for Cell Therapy, Asan Institute for Life Science, Asan Medical Center, Seoul 05505, Korea;
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Sang Ryong Kim
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41944, Korea;
- School of Life Sciences, Kyungpook National University, Daegu 41566, Korea
- BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
- Correspondence: ; Tel.: +82-53-950-7362; Fax: +82-53-943-2762
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Small GTPases of the Ras and Rho Families Switch on/off Signaling Pathways in Neurodegenerative Diseases. Int J Mol Sci 2020. [DOI: 10.3390/ijms21176312
expr 858053618 + 832508766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Small guanosine triphosphatases (GTPases) of the Ras superfamily are key regulators of many key cellular events such as proliferation, differentiation, cell cycle regulation, migration, or apoptosis. To control these biological responses, GTPases activity is regulated by guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs), and in some small GTPases also guanine nucleotide dissociation inhibitors (GDIs). Moreover, small GTPases transduce signals by their downstream effector molecules. Many studies demonstrate that small GTPases of the Ras family are involved in neurodegeneration processes. Here, in this review, we focus on the signaling pathways controlled by these small protein superfamilies that culminate in neurodegenerative pathologies, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Specifically, we concentrate on the two most studied families of the Ras superfamily: the Ras and Rho families. We summarize the latest findings of small GTPases of the Ras and Rho families in neurodegeneration in order to highlight these small proteins as potential therapeutic targets capable of slowing down different neurodegenerative diseases.
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Arrazola Sastre A, Luque Montoro M, Gálvez-Martín P, Lacerda HM, Lucia A, Llavero F, Zugaza JL. Small GTPases of the Ras and Rho Families Switch on/off Signaling Pathways in Neurodegenerative Diseases. Int J Mol Sci 2020; 21:E6312. [PMID: 32878220 PMCID: PMC7504559 DOI: 10.3390/ijms21176312] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 12/16/2022] Open
Abstract
Small guanosine triphosphatases (GTPases) of the Ras superfamily are key regulators of many key cellular events such as proliferation, differentiation, cell cycle regulation, migration, or apoptosis. To control these biological responses, GTPases activity is regulated by guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs), and in some small GTPases also guanine nucleotide dissociation inhibitors (GDIs). Moreover, small GTPases transduce signals by their downstream effector molecules. Many studies demonstrate that small GTPases of the Ras family are involved in neurodegeneration processes. Here, in this review, we focus on the signaling pathways controlled by these small protein superfamilies that culminate in neurodegenerative pathologies, such as Alzheimer's disease (AD) and Parkinson's disease (PD). Specifically, we concentrate on the two most studied families of the Ras superfamily: the Ras and Rho families. We summarize the latest findings of small GTPases of the Ras and Rho families in neurodegeneration in order to highlight these small proteins as potential therapeutic targets capable of slowing down different neurodegenerative diseases.
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Affiliation(s)
- Alazne Arrazola Sastre
- Achucarro Basque Center for Neuroscience, Science Park of the Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940 Leioa, Spain; (A.A.S.); (M.L.M.)
- Department of Genetics, Physical Anthropology, and Animal Physiology, Faculty of Science and Technology, UPV/EHU, 48940 Leioa, Spain
| | - Miriam Luque Montoro
- Achucarro Basque Center for Neuroscience, Science Park of the Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940 Leioa, Spain; (A.A.S.); (M.L.M.)
| | - Patricia Gálvez-Martín
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, 180041 Granada, Spain;
- R&D Human Health, Bioibérica S.A.U., 08950 Barcelona, Spain
| | | | - Alejandro Lucia
- Faculty of Sport Science, European University of Madrid, 28670 Madrid, Spain;
- Research Institute of the Hospital 12 de Octubre (i+12), 28041 Madrid, Spain
| | - Francisco Llavero
- Achucarro Basque Center for Neuroscience, Science Park of the Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940 Leioa, Spain; (A.A.S.); (M.L.M.)
- Faculty of Sport Science, European University of Madrid, 28670 Madrid, Spain;
| | - José Luis Zugaza
- Achucarro Basque Center for Neuroscience, Science Park of the Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940 Leioa, Spain; (A.A.S.); (M.L.M.)
- Department of Genetics, Physical Anthropology, and Animal Physiology, Faculty of Science and Technology, UPV/EHU, 48940 Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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