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Pethe A, Joshi S, Ali Dar T, Poddar NK. Revisiting the role of phospholipases in alzheimer's: crosstalk with processed food. Crit Rev Food Sci Nutr 2024:1-19. [PMID: 39002140 DOI: 10.1080/10408398.2024.2377290] [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: 07/15/2024]
Abstract
Phospholipases such as phospholipase-A, phospholipase-B, phospholipase-C and phospholipase-D are important functional enzymes of the cell membrane responsible for a variety of functions such as signal transduction, production of lipid mediators, metabolite digestion and playing a pathological role in central nervous system diseases. Phospholipases have shown an association with Alzheimer's disease and these enzymes have found a correlation with several metabolic pathways that can lead to the activation of inflammatory signals via astrocytes and microglial cells. We also highlighted unhealthy practices like smoking and consuming processed foods, rich in nitroso compounds and phosphatidic acid, which contribute to neuronal damage in AD through phospholipases. A few therapeutic approaches such as the use of inhibitors of phospholipase-D,phospholipase A2 as well as autophagy-mediated inhibition have been discussed to control the onset of AD. This paper serves as a crosstalk between phospholipases and their role in neurodegenerative pathways as well as their influence on other biomolecules of lipid membranes, which are acquired through unhealthy diets and possible methods to treat these anomalies occurring due to their metabolic disorder involving phospholipases acting as major signaling molecules.
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Affiliation(s)
- Atharv Pethe
- Department of Biosciences, Manipal University Jaipur, Jaipur, Rajasthan, India
| | - Siddhi Joshi
- Department of Biosciences, Manipal University Jaipur, Jaipur, Rajasthan, India
| | - Tanveer Ali Dar
- Department of Clinical Biochemistry, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Nitesh Kumar Poddar
- Department of Biosciences, Manipal University Jaipur, Jaipur, Rajasthan, India
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2
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Ravizza T, Scheper M, Di Sapia R, Gorter J, Aronica E, Vezzani A. mTOR and neuroinflammation in epilepsy: implications for disease progression and treatment. Nat Rev Neurosci 2024; 25:334-350. [PMID: 38531962 DOI: 10.1038/s41583-024-00805-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2024] [Indexed: 03/28/2024]
Abstract
Epilepsy remains a major health concern as anti-seizure medications frequently fail, and there is currently no treatment to stop or prevent epileptogenesis, the process underlying the onset and progression of epilepsy. The identification of the pathological processes underlying epileptogenesis is instrumental to the development of drugs that may prevent the generation of seizures or control pharmaco-resistant seizures, which affect about 30% of patients. mTOR signalling and neuroinflammation have been recognized as critical pathways that are activated in brain cells in epilepsy. They represent a potential node of biological convergence in structural epilepsies with either a genetic or an acquired aetiology. Interventional studies in animal models and clinical studies give strong support to the involvement of each pathway in epilepsy. In this Review, we focus on available knowledge about the pathophysiological features of mTOR signalling and the neuroinflammatory brain response, and their interactions, in epilepsy. We discuss mitigation strategies for each pathway that display therapeutic effects in experimental and clinical epilepsy. A deeper understanding of these interconnected molecular cascades could enhance our strategies for managing epilepsy. This could pave the way for new treatments to fill the gaps in the development of preventative or disease-modifying drugs, thus overcoming the limitations of current symptomatic medications.
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Affiliation(s)
- Teresa Ravizza
- Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research IRCCS, Milano, Italy
| | - Mirte Scheper
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Rossella Di Sapia
- Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research IRCCS, Milano, Italy
| | - Jan Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands.
| | - Annamaria Vezzani
- Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research IRCCS, Milano, Italy.
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3
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Nam KH, Ordureau A. How does the neuronal proteostasis network react to cellular cues? Biochem Soc Trans 2024; 52:581-592. [PMID: 38488108 DOI: 10.1042/bst20230316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 04/25/2024]
Abstract
Even though neurons are post-mitotic cells, they still engage in protein synthesis to uphold their cellular content balance, including for organelles, such as the endoplasmic reticulum or mitochondria. Additionally, they expend significant energy on tasks like neurotransmitter production and maintaining redox homeostasis. This cellular homeostasis is upheld through a delicate interplay between mRNA transcription-translation and protein degradative pathways, such as autophagy and proteasome degradation. When faced with cues such as nutrient stress, neurons must adapt by altering their proteome to survive. However, in many neurodegenerative disorders, such as Parkinson's disease, the pathway and processes for coping with cellular stress are impaired. This review explores neuronal proteome adaptation in response to cellular stress, such as nutrient stress, with a focus on proteins associated with autophagy, stress response pathways, and neurotransmitters.
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Affiliation(s)
- Ki Hong Nam
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, U.S.A
| | - Alban Ordureau
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, U.S.A
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Yue AC, Zhou XD, Song HP, Liu XH, Bi MJ, Han W, Li Q. Effect and molecular mechanism of Sulforaphane alleviates brain damage caused by acute carbon monoxide poisoning:Network pharmacology analysis, molecular docking, and experimental evidence. ENVIRONMENTAL TOXICOLOGY 2024; 39:1140-1162. [PMID: 37860845 DOI: 10.1002/tox.24000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 09/24/2023] [Accepted: 10/07/2023] [Indexed: 10/21/2023]
Abstract
Sulforaphane (SFN) has attracted much attention due to its ability on antioxidant, anti-inflammatory, and anti-apoptotic properties, while its functional targets and underlying mechanism of action on brain injury caused by acute carbon monoxide poisoning (ACOP) have not been fully elucidated. Herein, we used a systematic network pharmacology approach to explore the mechanism of SFN in the treatment of brain damage after ACOP. In this study, the results of network pharmacology demonstrated that there were a total of 81 effective target genes of SFN and 36 drug-disease targets, which were strongly in connection with autophagy-animal signaling pathway, drug metabolism, and transcription disorders in cancer. Upon the further biological function and KEGG signaling pathway enrichment analysis, a large number of them were involved in neuronal death, reactive oxygen metabolic processes and immune functions. Moreover, based on the results of bioinformatics prediction associated with multiple potential targets and pathways, the AMP-activated protein kinase (AMPK) signaling pathway was selected to elucidate the molecular mechanism of SFN in the treatment of brain injury caused by ACOP. The following molecular docking analysis also confirmed that SFN can bind to AMPKα well through chemical bonds. In addition, an animal model of ACOP was established by exposure to carbon monoxide in a hyperbaric oxygen chamber to verify the predicted results of network pharmacology. We found that the mitochondrial ultrastructure of neurons in rats with ACOP was seriously damaged, and apoptotic cells increased significantly. The histopathological changes were obviously alleviated, apoptosis of cortical neurons was inhibited, and the number of Nissl bodies was increased in the SFN group as compared with the ACOP group (p < .05). Besides, the administration of SFN could increase the expressions of phosphorylated P-AMPK and MFN2 proteins and decrease the levels of DRP1, Caspase3, and Casapase9 proteins in the brain tissue of ACOP rats. These findings suggest that network pharmacology is a useful tool for traditional Chinese medicine (TCM) research, SFN can effectively inhibit apoptosis, protect cortical neurons from the toxicity of carbon monoxide through activating the AMPK pathway and may become a potential therapeutic strategy for brain injury after ACOP.
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Affiliation(s)
- Ao-Chun Yue
- Emergency Department, Shenzhen University General Hospital, Shenzhen, People's Republic of China
- Centre of Integrated Chinese and Western Medicine, School of Clinical Medicine, Qingdao University, Qingdao, People's Republic of China
| | - Xu-Dong Zhou
- First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, People's Republic of China
| | - Hui-Ping Song
- First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, People's Republic of China
| | - Xu-Han Liu
- Emergency Department, Shenzhen University General Hospital, Shenzhen, People's Republic of China
| | - Ming-Jun Bi
- Physical Examination Centre, Yuhuangding Hospital Affiliated to Qingdao University, Yantai, People's Republic of China
| | - Wei Han
- Emergency Department, Shenzhen University General Hospital, Shenzhen, People's Republic of China
| | - Qin Li
- Emergency Department, Shenzhen University General Hospital, Shenzhen, People's Republic of China
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García-Juan M, Ordóñez-Gutiérrez L, Wandosell F. Clearance of β-amyloid mediated by autophagy is enhanced by MTORC1 inhibition but not AMPK activation in APP/PSEN1 astrocytes. Glia 2024; 72:588-606. [PMID: 38009275 DOI: 10.1002/glia.24492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/28/2023]
Abstract
Proteostasis mechanisms mediated by macroautophagy/autophagy are altered in neurodegenerative diseases such as Alzheimer disease (AD) and their recovery/enhancement has been proposed as a therapeutic approach. From the two central nodes in the anabolism-catabolism balance, it is generally accepted that mechanistic target of rapamycin kinase complex 1 (MTORC1)_ activation leads to the inhibition of autophagy, whereas adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) has the opposite role. In AD, amyloid beta (Aβ) production disturbs the optimal neuronal/glial proteostasis. As astrocytes are essential for brain homeostasis, the purpose of this work was to analyze if the upregulation of autophagy in this cell type, either by MTORC1 inhibition or AMPK activation, could modulate the generation/degradation of β-amyloid. By using primary astrocytes from amyloid beta precursor protein (APP)/Presenilin 1 (PSEN1) mouse model of AD, we confirmed that MTORC1 inhibition reduced Aβ secretion through moderate autophagy induction. Surprisingly, pharmacologically increased activity of AMPK did not enhance autophagy but had different effects on Aβ secretion. Conversely, AMPK inhibition did not affect autophagy but reduced Aβ secretion. These puzzling data were confirmed through the overexpression of different mutant AMPK isoforms: while only the constitutively active AMPK increased autophagy, all versions augmented Aβ secretion. We conclude that AMPK has a significantly different role in primary astrocytes than in other reported cells, similar to our previous findings in neurons. Our data support that perhaps only a basal AMPK activity is needed to maintain autophagy whereas the increased activity, either physiologically or pharmacologically, has no direct effect on autophagy-dependent amyloidosis. These results shed light on the controversy about the therapeutic effect of AMPK activation on autophagy induction.
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Affiliation(s)
- Marta García-Juan
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Nicolas Cabrera 1, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lara Ordóñez-Gutiérrez
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Nicolas Cabrera 1, Universidad Autónoma de Madrid, Madrid, Spain
- Departamento de Bioquímica ry Biología Molecular, Universidad Complutense de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Francisco Wandosell
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Nicolas Cabrera 1, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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Afiat BC, Zhao D, Wong VHY, Perera ND, Turner BJ, Nguyen CTO, Bui BV. Age-related deficits in retinal autophagy following intraocular pressure elevation in autophagy reporter mouse model. Neurobiol Aging 2023; 131:74-87. [PMID: 37586253 DOI: 10.1016/j.neurobiolaging.2023.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
This study quantified age-related changes to retinal autophagy using the CAG-RFP-EGFP-LC3 autophagy reporter mice and considered how aging impacts autophagic responses to acute intraocular pressure (IOP) stress. IOP was elevated to 50 mm Hg for 30 minutes in 3-month-old and 12-month-old CAG-RFP-EGFP-LC3 (n = 7 per age group) and Thy1-YFPh transgenic mice (n = 3 per age group). Compared with younger eyes, older eyes showed diminished basal autophagy in the outer retina, while the inner retina was unaffected. Autophagic flux (red:yellow puncta ratio) was elevated in the inner plexiform layer. Three days following IOP elevation, older eyes showed poorer functional recovery, most notably in ganglion cell responses compared to younger eyes (12 months old: -33.4 ± 5.3% vs. 3 months mice: -13.4 ± 4.5%). This paralleled a reduced capacity to upregulate autophagic puncta volume in the inner retina in older eyes, a response that was seen in younger eyes. Age-related decline in basal and stress-induced autophagy in the retina is associated with greater retinal ganglion cells' susceptibility to IOP elevation.
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Affiliation(s)
- Brianna C Afiat
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Nirma D Perera
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
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Li LF, Gao Y, Xu Y, Su DJ, Yang Q, Liu A, Wang SY, Tang XL, Zhao J, Luo L, Yan T, Wu YM, Liu SB, Zhao MG, Yang L. Praeruptorin C alleviates cognitive impairment in type 2 diabetic mice through restoring PI3K/AKT/GSK3β pathway. Phytother Res 2023; 37:4838-4850. [PMID: 37458182 DOI: 10.1002/ptr.7949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 10/18/2023]
Abstract
Diabetic encephalopathy is a common consequence of diabetes mellitus that causes cognitive dysfunction and neuropsychiatric disorders. Praeruptorin C (Pra-C) from the traditional Chinese medicinal herb Peucedanum praeruptorum Dunn. is a potential antioxidant and neuroprotective agent. This study was conducted to investigate the molecular mechanisms underlying the effect of Pra-C on diabetic cognitive impairment. A novel object recognition test and the Morris water maze test were performed to assess the behavioral performance of mice. Electrophysiological recordings were made to monitor synaptic plasticity in the hippocampus. A protein-protein interaction network of putative Pra-C targets was constructed, and molecular docking simulations were performed to predict the potential mechanisms of the action of Pra-C. Protein expression levels were detected by western blotting. Pra-C administration significantly lowered body weight and fasting blood glucose levels and alleviated learning and memory deficits in type 2 diabetic mice. Network pharmacology and molecular docking results suggested that Pra-C affects the PI3K/AKT/GSK3β signaling pathway. Western blot analysis confirmed significant increases in phosphorylated PI3K, AKT, and GSK3β levels in vivo and in vitro upon Pra-C administration. Pra-C alleviated cognitive impairment in type 2 diabetic mice by activating PI3K/AKT/GSK3β pathway.
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Affiliation(s)
- Long-Fei Li
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Ying Gao
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Yuan Xu
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Dan-Jie Su
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Qi Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - An Liu
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Sai-Ying Wang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Xiu-Ling Tang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Jun Zhao
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Li Luo
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Tao Yan
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Yu-Mei Wu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi'an, China
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi'an, China
| | - Ming-Gao Zhao
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
| | - Le Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, China
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Dharshika C, Gonzales J, Chow A, Morales-Soto W, Gulbransen BD. Stimulator of interferon genes (STING) expression in the enteric nervous system and contributions of glial STING in disease. Neurogastroenterol Motil 2023; 35:e14553. [PMID: 37309618 PMCID: PMC10266835 DOI: 10.1111/nmo.14553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/26/2023] [Accepted: 02/07/2023] [Indexed: 06/14/2023]
Abstract
BACKGROUND Appropriate host-microbe interactions are essential for enteric glial development and subsequent gastrointestinal function, but the potential mechanisms of microbe-glial communication are unclear. Here, we tested the hypothesis that enteric glia express the pattern recognition receptor stimulator of interferon genes (STING) and communicate with the microbiome through this pathway to modulate gastrointestinal inflammation. METHODS In situ transcriptional labeling and immunohistochemistry were used to examine STING and IFNβ expression in enteric neurons and glia. Glial-STING KO mice (Sox10CreERT2+/- ;STINGfl/fl ) and IFNβ ELISA were used to characterize the role of enteric glia in canonical STING activation. The role of glial STING in gastrointestinal inflammation was assessed in the 3% DSS colitis model. RESULTS Enteric glia and neurons express STING, but only enteric neurons express IFNβ. While both the myenteric and submucosal plexuses produce IFNβ with STING activation, enteric glial STING plays a minor role in its production and seems more involved in autophagy processes. Furthermore, deleting enteric glial STING does not affect weight loss, colitis severity, or neuronal cell proportions in the DSS colitis model. CONCLUSION Taken together, our data support canonical roles for STING and IFNβ signaling in the enteric nervous system through enteric neurons but that enteric glia do not use these same mechanisms. We propose that enteric glial STING may utilize alternative signaling mechanisms and/or is only active in particular disease conditions. Regardless, this study provides the first glimpse of STING signaling in the enteric nervous system and highlights a potential avenue of neuroglial-microbial communication.
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Affiliation(s)
- Christine Dharshika
- Department of Physiology, Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
- College of Human Medicine, Michigan State University, 804 Service Road, East Lansing, MI, 48824 USA
| | - Jacques Gonzales
- Department of Physiology, Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Aaron Chow
- Department of Physiology, Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Wilmarie Morales-Soto
- Department of Physiology, Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Brian D. Gulbransen
- Department of Physiology, Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
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Shan XQ, Luo YY, Chang J, Song JJ, Hao N, Zhao L. Immunomodulation: The next target of mesenchymal stem cell-derived exosomes in the context of ischemic stroke. World J Stem Cells 2023; 15:52-70. [PMID: 37007453 PMCID: PMC10052343 DOI: 10.4252/wjsc.v15.i3.52] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/19/2023] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
Ischemic stroke (IS) is the most prevalent form of brain disease, characterized by high morbidity, disability, and mortality. However, there is still a lack of ideal prevention and treatment measures in clinical practice. Notably, the transplantation therapy of mesenchymal stem cells (MSCs) has been a hot research topic in stroke. Nevertheless, there are risks associated with this cell therapy, including tumor formation, coagulation dysfunction, and vascular occlusion. Also, a growing number of studies suggest that the therapeutic effect after transplantation of MSCs is mainly attributed to MSC-derived exosomes (MSC-Exos). And this cell-free mediated therapy appears to circumvent many risks and difficulties when compared to cell therapy, and it may be the most promising new strategy for treating stroke as stem cell replacement therapy. Studies suggest that suppressing inflammation via modulation of the immune response is an additional treatment option for IS. Intriguingly, MSC-Exos mediates the inflammatory immune response following IS by modulating the central nervous system, the peripheral immune system, and immunomodulatory molecules, thereby promoting neurofunctional recovery after stroke. Thus, this paper reviews the role, potential mechanisms, and therapeutic potential of MSC-Exos in post-IS inflammation in order to identify new research targets.
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Affiliation(s)
- Xiao-Qian Shan
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300381, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300381, China
| | - Yong-Yin Luo
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300381, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300381, China
| | - Jun Chang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300381, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300381, China
| | - Jing-Jing Song
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300381, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300381, China
| | - Nan Hao
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300381, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300381, China
| | - Lan Zhao
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300381, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300381, China
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10
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Mendoza-Viveros L, Marmolejo-Gutierrez C, Cid-Castro C, Escalante-Covarrubias Q, Montellier E, Carreño-Vázquez E, Noriega LG, Velázquez-Villegas LA, Tovar AR, Sassone-Corsi P, Aguilar-Arnal L, Orozco-Solis R. Astrocytic circadian clock control of energy expenditure by transcriptional stress responses in the ventromedial hypothalamus. Glia 2023; 71:1626-1647. [PMID: 36919670 DOI: 10.1002/glia.24360] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/16/2023]
Abstract
Hypothalamic circuits compute systemic information to control metabolism. Astrocytes residing within the hypothalamus directly sense nutrients and hormones, integrating metabolic information, and modulating neuronal responses. Nevertheless, the role of the astrocytic circadian clock on the control of energy balance remains unclear. We used mice with a targeted ablation of the core-clock gene Bmal1 within Gfap-expressing astrocytes to gain insight on the role played by this transcription factor in astrocytes. While this mutation does not substantially affect the phenotype in mice fed normo-caloric diet, under high-fat diet we unmasked a thermogenic phenotype consisting of increased energy expenditure, and catabolism in brown adipose and overall metabolic improvement consisting of better glycemia control, and body composition. Transcriptomic analysis in the ventromedial hypothalamus revealed an enhanced response to moderate cellular stress, including ER-stress response, unfolded protein response and autophagy. We identified Xbp1 and Atf1 as two key transcription factors enhancing cellular stress responses. Therefore, we unveiled a previously unknown role of the astrocytic circadian clock modulating energy balance through the regulation of cellular stress responses within the VMH.
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Affiliation(s)
- Lucia Mendoza-Viveros
- Instituto Nacional de Medicina Genómica (INMEGEN), México City, Mexico
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México UNAM, México City, Mexico
- Centro de Investigación sobre el Envejecimiento, Centro de Investigación y de Estudios Avanzados (CIE-CINVESTAV), México City, México
| | | | - Carolina Cid-Castro
- Instituto Nacional de Medicina Genómica (INMEGEN), México City, Mexico
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México UNAM, México City, Mexico
- Centro de Investigación sobre el Envejecimiento, Centro de Investigación y de Estudios Avanzados (CIE-CINVESTAV), México City, México
| | | | | | | | - Lilia G Noriega
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | | | - Armando R Tovar
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | | | - Lorena Aguilar-Arnal
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México UNAM, México City, Mexico
| | - Ricardo Orozco-Solis
- Instituto Nacional de Medicina Genómica (INMEGEN), México City, Mexico
- Centro de Investigación sobre el Envejecimiento, Centro de Investigación y de Estudios Avanzados (CIE-CINVESTAV), México City, México
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11
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van Echten-Deckert G. The role of sphingosine 1-phosphate metabolism in brain health and disease. Pharmacol Ther 2023; 244:108381. [PMID: 36907249 DOI: 10.1016/j.pharmthera.2023.108381] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 03/13/2023]
Abstract
Lipids are essential structural and functional components of the central nervous system (CNS). Sphingolipids are ubiquitous membrane components which were discovered in the brain in the late 19th century. In mammals, the brain contains the highest concentration of sphingolipids in the body. Sphingosine 1-phosphate (S1P) derived from membrane sphingolipids evokes multiple cellular responses which, depending on its concentration and localization, make S1P a double-edged sword in the brain. In the present review we highlight the role of S1P in brain development and focus on the often contrasting findings regarding its contributions to the initiation, progression and potential recovery of different brain pathologies, including neurodegeneration, multiple sclerosis (MS), brain cancers, and psychiatric illnesses. A detailed understanding of the critical implications of S1P in brain health and disease may open the door for new therapeutic options. Thus, targeting S1P-metabolizing enzymes and/or signaling pathways might help overcome, or at least ameliorate, several brain illnesses.
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Coughlan ML, Maday S. Beyond housekeeping: autophagy regulates PKA signaling at synapses. Trends Neurosci 2023; 46:167-169. [PMID: 36717297 PMCID: PMC9990591 DOI: 10.1016/j.tins.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 01/11/2023] [Indexed: 01/30/2023]
Abstract
Autophagy modulates synaptic function and plasticity, but the molecular basis for this process is largely unknown. A recent tour de force study by Overhoff and colleagues identifies a novel role for autophagy in regulating PKA signaling at synapses to modulate the organization of the postsynaptic proteome and neuronal excitability.
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Affiliation(s)
- Maeve Louise Coughlan
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA.
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13
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Alam S, Afsar SY, Van Echten-Deckert G. S1P Released by SGPL1-Deficient Astrocytes Enhances Astrocytic ATP Production via S1PR 2,4, Thus Keeping Autophagy in Check: Potential Consequences for Brain Health. Int J Mol Sci 2023; 24:ijms24054581. [PMID: 36902011 PMCID: PMC10003137 DOI: 10.3390/ijms24054581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/02/2023] Open
Abstract
Astrocytes are critical players in brain health and disease. Sphingosine-1-phosphate (S1P), a bioactive signaling lipid, is involved in several vital processes, including cellular proliferation, survival, and migration. It was shown to be crucial for brain development. Its absence is embryonically lethal, affecting, inter alia, the anterior neural tube closure. However, an excess of S1P due to mutations in S1P-lyase (SGPL1), the enzyme responsible for its constitutive removal, is also harmful. Of note, the gene SGPL1 maps to a region prone to mutations in several human cancers and also in S1P-lyase insufficiency syndrome (SPLIS) characterized by several symptoms, including peripheral and central neurological defects. Here, we investigated the impact of S1P on astrocytes in a mouse model with the neural-targeted ablation of SGPL1. We found that SGPL1 deficiency, and hence the accumulation of its substrate, S1P, causes the elevated expression of glycolytic enzymes and preferentially directs pyruvate into the tricarboxylic acid (TCA) cycle through its receptors (S1PR2,4). In addition, the activity of TCA regulatory enzymes was increased, and consequently, so was the cellular ATP content. The high energy load activates the mammalian target of rapamycin (mTOR), thus keeping astrocytic autophagy in check. Possible consequences for the viability of neurons are discussed.
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14
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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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15
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Huang KC, Gomes C, Shiga Y, Belforte N, VanderWall KB, Lavekar SS, Fligor CM, Harkin J, Di Polo A, Meyer JS. Autophagy disruption reduces mTORC1 activation leading to retinal ganglion cell neurodegeneration associated with glaucoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.04.522687. [PMID: 36711831 PMCID: PMC9881969 DOI: 10.1101/2023.01.04.522687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Autophagy dysfunction has been associated with several neurodegenerative diseases including glaucoma, characterized by the degeneration of retinal ganglion cells (RGCs). However, the mechanisms by which autophagy dysfunction promotes RGC damage remain unclear. Here, we hypothesized that perturbation of the autophagy pathway results in increased autophagic demand, thereby downregulating signaling through mammalian target of rapamycin complex 1 (mTORC1), a negative regulator of autophagy, contributing to the degeneration of RGCs. We identified an impairment of autophagic-lysosomal degradation and decreased mTORC1 signaling via activation of the stress sensor adenosine monophosphate-activated protein kinase (AMPK), along with subsequent neurodegeneration in RGCs differentiated from human pluripotent stem cells (hPSCs) with a glaucoma-associated variant of Optineurin (OPTN-E50K). Similarly, the microbead occlusion model of glaucoma resulting in ocular hypertension also exhibited autophagy disruption and mTORC1 downregulation. Pharmacological inhibition of mTORC1 in hPSC-derived RGCs recapitulated disease-related neurodegenerative phenotypes in otherwise healthy RGCs, while the mTOR-independent induction of autophagy reduced protein accumulation and restored neurite outgrowth in diseased OPTN-E50K RGCs. Taken together, these results highlight an important balance between autophagy and mTORC1 signaling essential for RGC homeostasis, while disruption to these pathways contributes to neurodegenerative features in glaucoma, providing a potential therapeutic target to prevent neurodegeneration.
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Affiliation(s)
- Kang-Chieh Huang
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Cátia Gomes
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis IN USA
| | - Yukihiro Shiga
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
- University of Montreal Hospital Research Centre, Montreal, Quebec, Canada
| | - Nicolas Belforte
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
- University of Montreal Hospital Research Centre, Montreal, Quebec, Canada
| | - Kirstin B. VanderWall
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Sailee S. Lavekar
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Clarisse M. Fligor
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Jade Harkin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
- University of Montreal Hospital Research Centre, Montreal, Quebec, Canada
| | - Jason S. Meyer
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis IN USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN USA
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis IN USA
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16
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Dong AQ, Yang YP, Jiang SM, Yao XY, Qi D, Mao CJ, Cheng XY, Wang F, Hu LF, Liu CF. Pramipexole inhibits astrocytic NLRP3 inflammasome activation via Drd3-dependent autophagy in a mouse model of Parkinson's disease. Acta Pharmacol Sin 2023; 44:32-43. [PMID: 35896696 PMCID: PMC9813225 DOI: 10.1038/s41401-022-00951-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 06/28/2022] [Indexed: 01/18/2023] Open
Abstract
Inflammation is one of the pathogenic processes in Parkinson's disease (PD). Dopamine receptor agonist pramipexole (PPX) is extensively used for PD treatment in clinics. A number of studies show that PPX exerts neuroprotection on dopaminergic (DA) neurons, but the molecular mechanisms underlying the protective effects of PPX on DA neurons are not fully elucidated. In the present study, we investigated whether PPX modulated PD-related neuroinflammation and underlying mechanisms. PD model was established in mice by bilateral striatum injection of lipopolyssaccharide (LPS). The mice were administered PPX (0.5 mg·kg-1·d-1, i.p.) 3 days before LPS injection, and for 3 or 21 days after surgery, respectively, for biochemical and histological analyses. We showed that PPX administration significantly alleviated the loss of DA neurons, and suppressed the astrocyte activation and levels of proinflammatory cytokine IL-1β in the substantia nigra of LPS-injected mice. Furthermore, PPX administration significantly decreased the expression of NLRP3 inflammasome-associated proteins, i.e., cleaved forms of caspase-1, IL-1β, and apoptosis-associated speck-like protein containing a caspase recruit domain (ASC) in the striatum. These results were validated in LPS+ATP-stimulated primary mouse astrocytes in vitro. Remarkably, we showed that PPX (100-400 μM) dose-dependently enhanced the autophagy activity in the astrocytes evidenced by the elevations in LC3-II and BECN1 protein expression, as well as the increase of GFP-LC3 puncta formation. The opposite effects of PPX on astrocytic NLRP3 inflammasome and autophagy were eliminated by Drd3 depletion. Moreover, we demonstrated that both pretreatment of astrocytes with autophagy inhibitor chloroquine (40 μM) in vitro and astrocyte-specific Atg5 knockdown in vivo blocked PPX-caused inhibition on NLRP3 inflammasome and protection against DA neuron damage. Altogether, this study demonstrates an anti-neuroinflammatory activity of PPX via a Drd3-dependent enhancement of autophagy activity in astrocytes, and reveals a new mechanism for the beneficial effect of PPX in PD therapy.
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Affiliation(s)
- An-qi Dong
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China ,grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Ya-ping Yang
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China
| | - Shu-min Jiang
- grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Xiao-yu Yao
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China ,grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Di Qi
- grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Cheng-jie Mao
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China
| | - Xiao-yu Cheng
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China
| | - Fen Wang
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China ,grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Li-fang Hu
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China ,grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Chun-feng Liu
- grid.452666.50000 0004 1762 8363Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 China ,grid.263761.70000 0001 0198 0694Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123 China ,grid.512482.8Department of Neurology, The Second Affiliated Hospital of Xinjiang Medical University, Urumqi, 830000 China
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17
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Insulin and IGF-1 elicit robust transcriptional regulation to modulate autophagy in astrocytes. Mol Metab 2022; 66:101647. [PMID: 36503893 PMCID: PMC9731889 DOI: 10.1016/j.molmet.2022.101647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/08/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Insulin is a principal metabolic hormone. It regulates a plethora of metabolic pathways in peripheral tissues. The highly homologous insulin-like growth factor 1 (IGF-1), on the other hand, is important for development and growth. Recent studies have shown that insulin and IGF-1 signaling plays fundamental roles in the brain. Loss of insulin or IGF-1 receptors in astrocytes leads to altered glucose handling, mitochondrial metabolism, neurovascular coupling, and behavioral abnormalities in mice. Here, we aim to investigate molecular mechanisms by which insulin and IGF-1 signaling regulates astrocyte functions. METHODS IR-flox and IRKO primary astrocytes were treated with 100 nM insulin or IGF-1 for 6 h, and their transcriptomes were analyzed. Astrocytes with either IR deletion, IGF1R deletion or both were used to examine receptor-dependent transcriptional regulations using qPCR. Additional immunoblotting and confocal imaging studies were performed to functionally validate pathways involved in protein homeostasis. RESULTS Using next-generation RNA sequencing, we show that insulin significantly regulates the expression of over 1,200 genes involved in multiple functional processes in primary astrocytes. Insulin-like growth factor 1 (IGF-1) triggers a similar robust transcriptional regulation in astrocytes. Thus, over 50% of the differentially expressed genes are regulated by both ligands. As expected, these commonly regulated genes are highly enriched in pathways involved in lipid and cholesterol biosynthesis. Additionally, insulin and IGF-1 induce the expression of genes involved in ribosomal biogenesis, while suppressing the expression of genes involved in autophagy, indicating a common role of insulin and IGF-1 on protein homeostasis in astrocytes. Insulin-dependent suppression of autophagy genes, including p62, Ulk1/2, and several Atg genes, is blunted only when both IR and IGF1R are deleted. CONCLUSIONS In summary, insulin and IGF-1 potently suppress autophagy in astrocytes through transcriptional regulation. Both IR and IGF1R can elicit ligand-dependent transcriptional suppression of autophagy. These results demonstrate an important role of astrocytic insulin/IGF-1 signaling on proteostasis. Impairment of this regulation in insulin resistance and diabetes may contribute to neurological complications related to diabetes.
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18
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Kulkarni VV, Stempel MH, Anand A, Sidibe DK, Maday S. Retrograde Axonal Autophagy and Endocytic Pathways Are Parallel and Separate in Neurons. J Neurosci 2022; 42:8524-8541. [PMID: 36167783 PMCID: PMC9665928 DOI: 10.1523/jneurosci.1292-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/15/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022] Open
Abstract
Autophagy and endocytic trafficking are two key pathways that regulate the composition and integrity of the neuronal proteome. Alterations in these pathways are sufficient to cause neurodevelopmental and neurodegenerative disorders. Thus, defining how autophagy and endocytic pathways are organized in neurons remains a key area of investigation. These pathways share many features and converge on lysosomes for cargo degradation, but what remains unclear is the degree to which the identity of each pathway is preserved in each compartment of the neuron. Here, we elucidate the degree of intersection between autophagic and endocytic pathways in axons of primary mouse cortical neurons of both sexes. Using microfluidic chambers, we labeled newly-generated bulk endosomes and signaling endosomes in the distal axon, and systematically tracked their trajectories, molecular composition, and functional characteristics relative to autophagosomes. We find that newly-formed endosomes and autophagosomes both undergo retrograde transport in the axon, but as distinct organelle populations. Moreover, these pathways differ in their degree of acidification and association with molecular determinants of organelle maturation. These results suggest that the identity of autophagic and newly endocytosed organelles is preserved for the length of the axon. Lastly, we find that expression of a pathogenic form of α-synuclein, a protein enriched in presynaptic terminals, increases merging between autophagic and endocytic pathways. Thus, aberrant merging of these pathways may represent a mechanism contributing to neuronal dysfunction in Parkinson's disease (PD) and related α-synucleinopathies.SIGNIFICANCE STATEMENT Autophagy and endocytic trafficking are retrograde pathways in neuronal axons that fulfill critical degradative and signaling functions. These pathways share many features and converge on lysosomes for cargo degradation, but the extent to which the identity of each pathway is preserved in axons is unclear. We find that autophagosomes and endosomes formed in the distal axon undergo retrograde transport to the soma in parallel and separate pathways. These pathways also have distinct maturation profiles along the mid-axon, further highlighting differences in the potential fate of transported cargo. Strikingly, expression of a pathogenic variant of α-synuclein increases merging between autophagic and endocytic pathways, suggesting that mis-sorting of axonal cargo may contribute to neuronal dysfunction in Parkinson's disease (PD) and related α-synucleinopathies.
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Affiliation(s)
- Vineet Vinay Kulkarni
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Max Henry Stempel
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Anip Anand
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - David Kader Sidibe
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
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19
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IK Ca channels control breast cancer metabolism including AMPK-driven autophagy. Cell Death Dis 2022; 13:902. [PMID: 36302750 PMCID: PMC9613901 DOI: 10.1038/s41419-022-05329-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/28/2022] [Accepted: 10/07/2022] [Indexed: 11/30/2022]
Abstract
Ca2+-activated K+ channels of intermediate conductance (IK) are frequently overexpressed in breast cancer (BC) cells, while IK channel depletion reduces BC cell proliferation and tumorigenesis. This raises the question, of whether and mechanistically how IK activity interferes with the metabolic activity and energy consumption rates, which are fundamental for rapidly growing cells. Using BC cells obtained from MMTV-PyMT tumor-bearing mice, we show that both, glycolysis and mitochondrial ATP-production are reduced in cells derived from IK-deficient breast tumors. Loss of IK altered the sub-/cellular K+- and Ca2+- homeostasis and mitochondrial membrane potential, ultimately resulting in reduced ATP-production and metabolic activity. Consequently, we find that BC cells lacking IK upregulate AMP-activated protein kinase activity to induce autophagy compensating the glycolytic and mitochondrial energy shortage. Our results emphasize that IK by modulating cellular Ca2+- and K+-dynamics contributes to the remodeling of metabolic pathways in cancer. Thus, targeting IK channel might disturb the metabolic activity of BC cells and reduce malignancy.
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20
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Lan T, Xu Y, Li S, Li N, Zhang S, Zhu H. Cornin protects against cerebral ischemia/reperfusion injury by preventing autophagy via the PI3K/Akt/mTOR pathway. BMC Pharmacol Toxicol 2022; 23:82. [PMID: 36280856 PMCID: PMC9594897 DOI: 10.1186/s40360-022-00620-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 10/10/2022] [Indexed: 11/30/2022] Open
Abstract
Background Ischemia stroke is the leading cause of disability, which is a consequence of vascular occlusion. The purpose of this study is to investigate the effect of cornin which is isolated from the fruit of Verbena officinalis L, against astrocytes autophagy induced by cerebral ischemia/reperfusion (CI/R) injury in vitro and in vivo and its potential mechanism. Methods Cornin at dose of 2.5, 5 and 10 mg/kg were intravenously injected to MCAO rats at 15 min after reperfusion. The infarction volume, blood–brain barrier (BBB), neurological severity score (mNSS), and autophagy related protein were used to evaluated the protective effects and potential mechanism of cornin in autophagy with or without phosphoinositide-3 kinase (PI3K)inhibitor LY294002 and mammalian target of rapamycin (mTOR) small interfering RNA (siRNA) at 24 h after CI/R injury. The potential protective effects and mechanism of cornin at concention of 10 ~ 1000 nM were also evaluated in oxygen glucose deprivation/reperfusion (OGD/R) in U87 cells. Results The results suggest that cornin at dose of 5 or 10 mg/kg significantly reduce the cerebral infarction volume and blood–brain barrier (BBB) leakage, and improve neurological recovery in MCAO rats. Cleaved caspase-3 and Bax levels were significantly decreased, while B-cell lymphoma-2 (Bcl-2) and the apoptosis regulator ratio (Bcl-2/Bax) were markedly increased when treated with 2.5–10 mg/kg cornin. The obvious decreased expressions of glial fibrillary acidic protein (GFAP), myosin-like BCL2 interacting protein (Beclin-1) and microtubule-associated protein light chain 3 II (LC3-II) and increased of neuronal nuclei (NeuN), sequestosome-1 (p62), phosphorylated mTOR (p-mTOR), and phosphorylated Akt (p-Akt) were observed in MCAO rats treated with 10 mg/kg cornin, which was counteracted by LY294002. The expression of autophagy-related proteins with or without LY294002 and mTOR siRNA presented the similar results as in vitro in OGD/R in U87 cells. Conclusions These results indicate that cornin improved neurological recovery after cerebral ischemia injury by preventing astrocytes autophagy induced by CI/R via the PI3K/Akt/mTOR signaling pathway. Supplementary Information The online version contains supplementary material available at 10.1186/s40360-022-00620-3.
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Affiliation(s)
- Tianchi Lan
- grid.440653.00000 0000 9588 091XDepartment of Pharmacology, Binzhou Medical University, Yantai, Shandong 264003 People’s Republic of China
| | - Yangyang Xu
- grid.452240.50000 0004 8342 6962Department of Pharmacy, Binzhou Medical University Hospital, Binzhou, Shandong 256603 People’s Republic of China
| | - Shucui Li
- grid.440653.00000 0000 9588 091XDepartment of Pharmacology, Binzhou Medical University, Yantai, Shandong 264003 People’s Republic of China
| | - Ning Li
- grid.440653.00000 0000 9588 091XSchool of Public Health and Management, Binzhou Medical University, Yantai, Shandong 264003 People’s Republic of China
| | - Shuping Zhang
- grid.440653.00000 0000 9588 091XDepartment of Pharmacology, Binzhou Medical University, Yantai, Shandong 264003 People’s Republic of China
| | - Haibo Zhu
- grid.440653.00000 0000 9588 091XSchool of Public Health and Management, Binzhou Medical University, Yantai, Shandong 264003 People’s Republic of China
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21
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Su PW, Zhai Z, Wang T, Zhang YN, Wang Y, Ma K, Han BB, Wu ZC, Yu HY, Zhao HJ, Wang SJ. Research progress on astrocyte autophagy in ischemic stroke. Front Neurol 2022; 13:951536. [PMID: 36110390 PMCID: PMC9468275 DOI: 10.3389/fneur.2022.951536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
Ischemic stroke is a highly disabling and potentially fatal disease. After ischemic stroke, autophagy plays a key regulatory role as an intracellular catabolic pathway for misfolded proteins and damaged organelles. Mounting evidence indicates that astrocytes are strongly linked to the occurrence and development of cerebral ischemia. In recent years, great progress has been made in the investigation of astrocyte autophagy during ischemic stroke. This article summarizes the roles and potential mechanisms of astrocyte autophagy in ischemic stroke, briefly expounds on the crosstalk of astrocyte autophagy with pathological mechanisms and its potential protective effect on neurons, and reviews astrocytic autophagy-targeted therapeutic methods for cerebral ischemia. The broader aim of the report is to provide new perspectives and strategies for the treatment of cerebral ischemia and a reference for future research on cerebral ischemia.
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Affiliation(s)
- Pei-Wei Su
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Zhe Zhai
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Tong Wang
- School of Nursing, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Ya-Nan Zhang
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yuan Wang
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Ke Ma
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Bing-Bing Han
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Zhi-Chun Wu
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hua-Yun Yu
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hai-Jun Zhao
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
- *Correspondence: Hai-Jun Zhao
| | - Shi-Jun Wang
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula, Shandong University of Traditional Chinese Medicine, Jinan, China
- Shi-Jun Wang
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Therapeutic functions of astrocytes to treat α-synuclein pathology in Parkinson’s disease. Proc Natl Acad Sci U S A 2022; 119:e2110746119. [PMID: 35858361 PMCID: PMC9304026 DOI: 10.1073/pnas.2110746119] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Intraneuronal inclusions of misfolded α-synuclein (α-syn) and prion-like spread of the pathologic α-syn contribute to progressive neuronal death in Parkinson’s disease (PD). Despite the pathologic significance, no efficient therapeutic intervention targeting α-synucleinopathy has been developed. In this study, we provide evidence that astrocytes, especially those cultured from the ventral midbrain (VM), show therapeutic potential to alleviate α-syn pathology in multiple in vitro and in vivo α-synucleinopathic models. Regulation of neuronal α-syn proteostasis underlies the therapeutic function of astrocytes. Specifically, VM-derived astrocytes inhibited neuronal α-syn aggregation and transmission in a paracrine manner by correcting not only intraneuronal oxidative and mitochondrial stresses but also extracellular inflammatory environments, in which α-syn proteins are prone to pathologic misfolding. The astrocyte-derived paracrine factors also promoted disassembly of extracellular α-syn aggregates. In addition to the aggregated form of α-syn, VM astrocytes reduced total α-syn protein loads both by actively scavenging extracellular α-syn fibrils and by a paracrine stimulation of neuronal autophagic clearance of α-syn. Transplantation of VM astrocytes into the midbrain of PD model mice alleviated α-syn pathology and protected the midbrain dopamine neurons from neurodegeneration. We further showed that cografting of VM astrocytes could be exploited in stem cell–based therapy for PD, in which host-to-graft transmission of α-syn pathology remains a critical concern for long-term cell therapeutic effects.
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23
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Autophagy: Identification of MTMR5 as a neuron-enriched suppressor. Curr Biol 2022; 32:R574-R577. [PMID: 35728530 PMCID: PMC9994184 DOI: 10.1016/j.cub.2022.04.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A puzzle of autophagy in neurons is that, unlike in other cells, it is not robustly induced by inhibition of mammalian target of rapamycin (mTOR). A new study now solves this conundrum and establishes that myotubularin-related phosphatase 5 limits the induction of neuronal autophagy by mTOR inhibitors.
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24
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Yap CC, Winckler B. Spatial regulation of endosomes in growing dendrites. Dev Biol 2022; 486:5-14. [PMID: 35306006 PMCID: PMC10646839 DOI: 10.1016/j.ydbio.2022.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/21/2022] [Accepted: 03/13/2022] [Indexed: 01/19/2023]
Abstract
Many membrane proteins are highly enriched in either dendrites or axons. This non-uniform distribution is a critical feature of neuronal polarity and underlies neuronal function. The molecular mechanisms responsible for polarized distribution of membrane proteins has been studied for some time and many answers have emerged. A less well studied feature of neurons is that organelles are also frequently non-uniformly distributed. For instance, EEA1-positive early endosomes are somatodendritic whereas synaptic vesicles are axonal. In addition, some organelles are present in both axons and dendrites, but not distributed uniformly along the processes. One well known example are lysosomes which are abundant in the soma and proximal dendrite, but sparse in the distal dendrite and the distal axon. The mechanisms that determine the spatial distribution of organelles along dendrites are only starting to be studied. In this review, we will discuss the cell biological mechanisms of how the distribution of diverse sets of endosomes along the proximal-distal axis of dendrites might be regulated. In particular, we will focus on the regulation of bulk homeostatic mechanisms as opposed to local regulation. We posit that immature dendrites regulate organelle motility differently from mature dendrites in order to spatially organize dendrite growth, branching and sculpting.
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25
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Gundelfinger ED, Karpova A, Pielot R, Garner CC, Kreutz MR. Organization of Presynaptic Autophagy-Related Processes. Front Synaptic Neurosci 2022; 14:829354. [PMID: 35368245 PMCID: PMC8968026 DOI: 10.3389/fnsyn.2022.829354] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Brain synapses pose special challenges on the quality control of their protein machineries as they are far away from the neuronal soma, display a high potential for plastic adaptation and have a high energy demand to fulfill their physiological tasks. This applies in particular to the presynaptic part where neurotransmitter is released from synaptic vesicles, which in turn have to be recycled and refilled in a complex membrane trafficking cycle. Pathways to remove outdated and damaged proteins include the ubiquitin-proteasome system acting in the cytoplasm as well as membrane-associated endolysosomal and the autophagy systems. Here we focus on the latter systems and review what is known about the spatial organization of autophagy and endolysomal processes within the presynapse. We provide an inventory of which components of these degradative systems were found to be present in presynaptic boutons and where they might be anchored to the presynaptic apparatus. We identify three presynaptic structures reported to interact with known constituents of membrane-based protein-degradation pathways and therefore may serve as docking stations. These are (i) scaffolding proteins of the cytomatrix at the active zone, such as Bassoon or Clarinet, (ii) the endocytic machinery localized mainly at the peri-active zone, and (iii) synaptic vesicles. Finally, we sketch scenarios, how presynaptic autophagic cargos are tagged and recruited and which cellular mechanisms may govern membrane-associated protein turnover in the presynapse.
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Affiliation(s)
- Eckart D. Gundelfinger
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Institute of Pharmacology and Toxicology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- *Correspondence: Eckart D. Gundelfinger,
| | - Anna Karpova
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Rainer Pielot
- Institute of Pharmacology and Toxicology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Craig C. Garner
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Michael R. Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Center for Molecular Neurobiology (ZMNH), University Hospital Hamburg-Eppendorf, Hamburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
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26
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Gómez O, Perini-Villanueva G, Yuste A, Rodríguez-Navarro JA, Poch E, Bejarano E. Autophagy and Glycative Stress: A Bittersweet Relationship in Neurodegeneration. Front Cell Dev Biol 2022; 9:790479. [PMID: 35004686 PMCID: PMC8733682 DOI: 10.3389/fcell.2021.790479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/06/2021] [Indexed: 12/27/2022] Open
Abstract
Autophagy is a fine-tuned proteolytic pathway that moves dysfunctional/aged cellular components into the lysosomal compartment for degradation. Over the last 3 decades, global research has provided evidence for the protective role of autophagy in different brain cell components. Autophagic capacities decline with age, which contributes to the accumulation of obsolete/damaged organelles and proteins and, ultimately, leads to cellular aging in brain tissues. It is thus well-accepted that autophagy plays an essential role in brain homeostasis, and malfunction of this catabolic system is associated with major neurodegenerative disorders. Autophagy function can be modulated by different types of stress, including glycative stress. Glycative stress is defined as a cellular status with abnormal and accelerated accumulation of advanced glycation end products (AGEs). It occurs in hyperglycemic states, both through the consumption of high-sugar diets or under metabolic conditions such as diabetes. In recent years, glycative stress has gained attention for its adverse impact on brain pathology. This is because glycative stress stimulates insoluble, proteinaceous aggregation that is linked to the malfunction of different neuropathological proteins. Despite the emergence of new literature suggesting that autophagy plays a major role in fighting glycation-derived damage by removing cytosolic AGEs, excessive glycative stress might also negatively impact autophagic function. In this mini-review, we provide insight on the status of present knowledge regarding the role of autophagy in brain physiology and pathophysiology, with an emphasis on the cytoprotective role of autophagic function to ameliorate the adverse effects of glycation-derived damage in neurons, glia, and neuron-glia interactions.
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Affiliation(s)
- Olga Gómez
- School of Health Sciences and Veterinary School, Universidad CEU Cardenal Herrera, CEU Universities, Valencia, Spain
| | - Giuliana Perini-Villanueva
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, United States
| | - Andrea Yuste
- School of Health Sciences and Veterinary School, Universidad CEU Cardenal Herrera, CEU Universities, Valencia, Spain
| | | | - Enric Poch
- School of Health Sciences and Veterinary School, Universidad CEU Cardenal Herrera, CEU Universities, Valencia, Spain
| | - Eloy Bejarano
- School of Health Sciences and Veterinary School, Universidad CEU Cardenal Herrera, CEU Universities, Valencia, Spain
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27
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Tavčar Verdev P, Potokar M, Korva M, Resman Rus K, Kolenc M, Avšič Županc T, Zorec R, Jorgačevski J. In human astrocytes neurotropic flaviviruses increase autophagy, yet their replication is autophagy-independent. Cell Mol Life Sci 2022; 79:566. [PMID: 36283999 PMCID: PMC9596533 DOI: 10.1007/s00018-022-04578-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 01/18/2023]
Abstract
Astrocytes, an abundant type of glial cells, are the key cells providing homeostasis in the central nervous system. Due to their susceptibility to infection, combined with high resilience to virus-induced cell death, astrocytes are now considered one of the principal types of cells, responsible for virus retention and dissemination within the brain. Autophagy plays an important role in elimination of intracellular components and in maintaining cellular homeostasis and is also intertwined with the life cycle of viruses. The physiological significance of autophagy in astrocytes, in connection with the life cycle and transmission of viruses, remains poorly investigated. In the present study, we investigated flavivirus-induced modulation of autophagy in human astrocytes by monitoring a tandem fluorescent-tagged LC3 probe (mRFP-EGFP-LC3) with confocal and super-resolution fluorescence microscopy. Astrocytes were infected with tick-borne encephalitis virus (TBEV) or West Nile virus (WNV), both pathogenic flaviviruses, and with mosquito-only flavivirus (MOF), which is considered non-pathogenic. The results revealed that human astrocytes are susceptible to infection with TBEV, WNV and to a much lower extent also to MOF. Infection and replication rates of TBEV and WNV are paralleled by increased rate of autophagy, whereas autophagosome maturation and the size of autophagic compartments are not affected. Modulation of autophagy by rapamycin and wortmannin does not influence TBEV and WNV replication rate, whereas bafilomycin A1 attenuates their replication and infectivity. In human astrocytes infected with MOF, the low infectivity and the lack of efficient replication of this flavivirus are mirrored by the absence of an autophagic response.
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Affiliation(s)
- Petra Tavčar Verdev
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Maja Potokar
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ,grid.433223.7Celica Biomedical, Ljubljana, Slovenia
| | - Miša Korva
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katarina Resman Rus
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Kolenc
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tatjana Avšič Županc
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ,grid.433223.7Celica Biomedical, Ljubljana, Slovenia
| | - Jernej Jorgačevski
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ,grid.433223.7Celica Biomedical, Ljubljana, Slovenia
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28
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Gao X, Yu M, Sun W, Han Y, Yang J, Lu X, Jin C, Wu S, Cai Y. Lanthanum chloride induces autophagy in primary cultured rat cortical neurons through Akt/mTOR and AMPK/mTOR signaling pathways. Food Chem Toxicol 2021; 158:112632. [PMID: 34688703 DOI: 10.1016/j.fct.2021.112632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 09/30/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022]
Abstract
Autophagy is a lysosome dependent degradation pathway occurring in eukaryotic cells. Autophagy ensures balance and survival mechanism of cells during harmful stress. Excessive or weak autophagy leads to abnormal function and death in some cases. Lanthanum (La), a rare earth element (REE), damages the central nervous system (CNS) and promotes learning and memory dysfunction. However, underlying mechanism has not been fully elucidated. La induces oxidative stress, inhibits Nrf2/ARE and Akt/mTOR signaling pathways, and activates JNK/c-Jun and JNK/Foxo signaling pathways, resulting in abnormal induction of autophagy in rat hippocampus. In addition, La activates PINK1- Parkin signaling pathway and induces mitochondrial autophagy. However, the relationship between La and autophagy in rat neurons at the cellular level has not been explored previously. The aim of this study was to explore adverse effects of La. Primary culture of rat neurons were exposed to 0 mmol/L, 0.025 mmol/L, 0.05 mmol/L and 0.1 mmol/L lanthanum chloride (LaCl3). The results showed that La upregulates p-AMPK, inhibits levels of p-Akt and p-mTOR, increases levels of autophagy related proteins (Beclin1 and LC3B-II), and downregulates expression of p-Bcl-2 and p62. Upstream and downstream intervention agents of autophagy were used to detect autophagy flux to verify accuracy of our results. Electron microscopy results showed significant increase in the number of autophagosomes in LaCl3 exposed groups. These findings imply that LaCl3 inhibits Akt/mTOR signaling pathway and activates AMPK/mTOR signaling pathway, resulting in abnormal autophagy in primary cultured rat cortical neurons. In addition, LaCl3 induces neuronal damage through excessive autophagy.
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Affiliation(s)
- Xiang Gao
- Key Lab of Environment and Health, School of Public Health, Xuzhou Medical University, No.209 Tongshan Road, Xuzhou, 221000, Jiangsu Province, People's Republic of China; Department of Biostatistics, School of Public Health, Xuzhou Medical University, No.209 Tongshan Road, Xuzhou, 221000, Jiangsu Province, People's Republic of China.
| | - Miao Yu
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Wenchang Sun
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Yarao Han
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Jinghua Yang
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Xiaobo Lu
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Cuihong Jin
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Shengwen Wu
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
| | - Yuan Cai
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
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29
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Dang R, Yang M, Cui C, Wang C, Zhang W, Geng C, Han W, Jiang P. Activation of angiotensin-converting enzyme 2/angiotensin (1-7)/mas receptor axis triggers autophagy and suppresses microglia proinflammatory polarization via forkhead box class O1 signaling. Aging Cell 2021; 20:e13480. [PMID: 34529881 PMCID: PMC8520723 DOI: 10.1111/acel.13480] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 07/03/2021] [Accepted: 08/05/2021] [Indexed: 12/14/2022] Open
Abstract
Brain renin‐angiotensin (Ang) system (RAS) is implicated in neuroinflammation, a major characteristic of aging process. Angiotensin (Ang) II, produced by angiotensin‐converting enzyme (ACE), activates immune system via angiotensin type 1 receptor (AT1), whereas Ang(1–7), generated by ACE2, binds with Mas receptor (MasR) to restrain excessive inflammatory response. Therefore, the present study aims to explore the relationship between RAS and neuroinflammation. We found that repeated lipopolysaccharide (LPS) treatment shifted the balance between ACE/Ang II/AT1 and ACE2/Ang(1–7)/MasR axis to the deleterious side and treatment with either MasR agonist, AVE0991 (AVE) or ACE2 activator, diminazene aceturate, exhibited strong neuroprotective actions. Mechanically, activation of ACE2/Ang(1–7)/MasR axis triggered the Forkhead box class O1 (FOXO1)‐autophagy pathway and induced superoxide dismutase (SOD) and catalase (CAT), the FOXO1‐targeted antioxidant enzymes. Meanwhile, knockdown of MasR or FOXO1 in BV2 cells, or using the selective FOXO1 inhibitor, AS1842856, in animals, suppressed FOXO1 translocation and compromised the autophagic process induced by MasR activation. We further used chloroquine (CQ) to block autophagy and showed that suppressing either FOXO1 or autophagy abrogated the anti‐inflammatory action of AVE. Likewise, Ang(1–7) also induced FOXO1 signaling and autophagic flux following LPS treatment in BV2 cells. Cotreatment with AS1842856 or CQ all led to autophagic inhibition and thereby abolished Ang(1–7)‐induced remission on NLRP3 inflammasome activation caused by LPS exposure, shifting the microglial polarization from M1 to M2 phenotype. Collectively, these results firstly illustrated the mechanism of ACE2/Ang(1–7)/MasR axis in neuroinflammation, strongly indicating the involvement of FOXO1‐mediated autophagy in the neuroimmune‐modulating effects triggered by MasR activation.
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Affiliation(s)
- Ruili Dang
- Institute of Clinical Pharmacy and Pharmacology Jining First People’s HospitalJining Medical University Jining China
| | - Mengqi Yang
- Institute of Clinical Pharmacy and Pharmacology Jining First People’s HospitalJining Medical University Jining China
| | - Changmeng Cui
- Department of Neurosurgery Affiliated Hospital of Jining Medical University Jining China
| | - Changshui Wang
- Department of Neurosurgery Affiliated Hospital of Jining Medical University Jining China
| | - Wenyuan Zhang
- Department of Pharmacy Zhongshan Affiliated Hospital of Zhongshan University Zhongshan China
| | - Chunmei Geng
- Institute of Clinical Pharmacy and Pharmacology Jining First People’s HospitalJining Medical University Jining China
| | - Wenxiu Han
- Institute of Clinical Pharmacy and Pharmacology Jining First People’s HospitalJining Medical University Jining China
| | - Pei Jiang
- Institute of Clinical Pharmacy and Pharmacology Jining First People’s HospitalJining Medical University Jining China
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30
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Sukhorukov V, Voronkov D, Baranich T, Mudzhiri N, Magnaeva A, Illarioshkin S. Impaired Mitophagy in Neurons and Glial Cells during Aging and Age-Related Disorders. Int J Mol Sci 2021; 22:10251. [PMID: 34638589 PMCID: PMC8508639 DOI: 10.3390/ijms221910251] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/18/2021] [Accepted: 09/22/2021] [Indexed: 12/17/2022] Open
Abstract
Aging is associated with a decline in cognitive function, which can partly be explained by the accumulation of damage to the brain cells over time. Neurons and glia undergo morphological and ultrastructure changes during aging. Over the past several years, it has become evident that at the cellular level, various hallmarks of an aging brain are closely related to mitophagy. The importance of mitochondria quality and quantity control through mitophagy is highlighted by the contribution that defects in mitochondria-autophagy crosstalk make to aging and age-related diseases. In this review, we analyze some of the more recent findings regarding the study of brain aging and neurodegeneration in the context of mitophagy. We discuss the data on the dynamics of selective autophagy in neurons and glial cells during aging and in the course of neurodegeneration, focusing on three mechanisms of mitophagy: non-receptor-mediated mitophagy, receptor-mediated mitophagy, and transcellular mitophagy. We review the role of mitophagy in neuronal/glial homeostasis and in the molecular pathogenesis of neurodegenerative disorders, such as Parkinson's disease, Alzheimer's disease, and other disorders. Common mechanisms of aging and neurodegeneration that are related to different mitophagy pathways provide a number of promising targets for potential therapeutic agents.
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Affiliation(s)
- Vladimir Sukhorukov
- Research Center of Neurology, Department for Brain Research, 125367 Moscow, Russia; (D.V.); (T.B.); (N.M.); (A.M.); (S.I.)
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31
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Patrizz AN, Moruno-Manchon JF, O’Keefe LM, Doran SJ, Patel AR, Venna VR, Tsvetkov AS, Li J, McCullough LD. Sex-Specific Differences in Autophagic Responses to Experimental Ischemic Stroke. Cells 2021; 10:cells10071825. [PMID: 34359998 PMCID: PMC8304137 DOI: 10.3390/cells10071825] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/25/2022] Open
Abstract
Ischemic stroke triggers a series of complex pathophysiological processes including autophagy. Differential activation of autophagy occurs in neurons derived from males versus females after stressors such as nutrient deprivation. Whether autophagy displays sexual dimorphism after ischemic stroke is unknown. We used a cerebral ischemia mouse model (middle cerebral artery occlusion, MCAO) to evaluate the effects of inhibiting autophagy in ischemic brain pathology. We observed that inhibiting autophagy reduced infarct volume in males and ovariectomized females. However, autophagy inhibition enhanced infarct size in females and in ovariectomized females supplemented with estrogen compared to control mice. We also observed that males had increased levels of Beclin1 and LC3 and decreased levels of pULK1 and p62 at 24 h, while females had decreased levels of Beclin1 and increased levels of ATG7. Furthermore, the levels of autophagy markers were increased under basal conditions and after oxygen and glucose deprivation in male neurons compared with female neurons in vitro. E2 supplementation significantly inhibited autophagy only in male neurons, and was beneficial for cell survival only in female neurons. This study shows that autophagy in the ischemic brain differs between the sexes, and that autophagy regulators have different effects in a sex-dependent manner in neurons.
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Affiliation(s)
- Anthony N. Patrizz
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA; (A.N.P.); (J.F.M.-M.); (V.R.V.); (A.S.T.); (J.L.)
| | - Jose F. Moruno-Manchon
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA; (A.N.P.); (J.F.M.-M.); (V.R.V.); (A.S.T.); (J.L.)
| | - Lena M. O’Keefe
- Department of Neurology, Beth Israel Deaconess Hospital, 330 Brookline Avenue, Boston, MA 02215, USA;
| | - Sarah J. Doran
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA; (S.J.D.); (A.R.P.)
| | - Anita R. Patel
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA; (S.J.D.); (A.R.P.)
| | - Venugopal R. Venna
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA; (A.N.P.); (J.F.M.-M.); (V.R.V.); (A.S.T.); (J.L.)
| | - Andrey S. Tsvetkov
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA; (A.N.P.); (J.F.M.-M.); (V.R.V.); (A.S.T.); (J.L.)
| | - Jun Li
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA; (A.N.P.); (J.F.M.-M.); (V.R.V.); (A.S.T.); (J.L.)
| | - Louise D. McCullough
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA; (A.N.P.); (J.F.M.-M.); (V.R.V.); (A.S.T.); (J.L.)
- Correspondence:
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32
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Zapata-Muñoz J, Villarejo-Zori B, Largo-Barrientos P, Boya P. Towards a better understanding of the neuro-developmental role of autophagy in sickness and in health. Cell Stress 2021; 5:99-118. [PMID: 34308255 PMCID: PMC8283300 DOI: 10.15698/cst2021.07.253] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 01/18/2023] Open
Abstract
Autophagy is a critical cellular process by which biomolecules and cellular organelles are degraded in an orderly manner inside lysosomes. This process is particularly important in neurons: these post-mitotic cells cannot divide or be easily replaced and are therefore especially sensitive to the accumulation of toxic proteins and damaged organelles. Dysregulation of neuronal autophagy is well documented in a range of neurodegenerative diseases. However, growing evidence indicates that autophagy also critically contributes to neurodevelopmental cellular processes, including neurogenesis, maintenance of neural stem cell homeostasis, differentiation, metabolic reprogramming, and synaptic remodelling. These findings implicate autophagy in neurodevelopmental disorders. In this review we discuss the current understanding of the role of autophagy in neurodevelopment and neurodevelopmental disorders, as well as currently available tools and techniques that can be used to further investigate this association.
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Affiliation(s)
- Juan Zapata-Muñoz
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | | | | | - Patricia Boya
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
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33
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Orhon I, Rocchi C, Villarejo-Zori B, Serrano Martinez P, Baanstra M, Brouwer U, Boya P, Coppes R, Reggiori F. Autophagy induction during stem cell activation plays a key role in salivary gland self-renewal. Autophagy 2021; 18:293-308. [PMID: 34009100 PMCID: PMC8942426 DOI: 10.1080/15548627.2021.1924036] [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] [Indexed: 12/22/2022] Open
Abstract
Relatively quiescent tissues like salivary glands (SGs) respond to stimuli such as injury to expand, replace and regenerate. Resident stem/progenitor cells are key in this process because, upon activation, they possess the ability to self-renew. Macroautophagy/autophagy contributes to and regulates differentiation in adult tissues, but an important question is whether this pathway promotes stem cell self-renewal in tissues. We took advantage of a 3D organoid system that allows assessing the self-renewal of mouse SGs stem cells (SGSCs). We found that autophagy in dormant SGSCs has slower flux than self-renewing SGSCs. Importantly, autophagy enhancement upon SGSCs activation is a self-renewal feature in 3D organoid cultures and SGs regenerating in vivo. Accordingly, autophagy ablation in SGSCs inhibits self-renewal whereas pharmacological stimulation promotes self-renewal of mouse and human SGSCs. Thus, autophagy is a key pathway for self-renewal activation in low proliferative adult tissues, and its pharmacological manipulation has the potential to promote tissue regeneration.
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Affiliation(s)
- Idil Orhon
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Cecilia Rocchi
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Beatriz Villarejo-Zori
- Department of Cellular and Molecular Biology, Centro De Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Paola Serrano Martinez
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Mirjam Baanstra
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Uilke Brouwer
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Patricia Boya
- Department of Cellular and Molecular Biology, Centro De Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Rob Coppes
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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34
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Abstract
Background The brain was once thought of as an insulin-insensitive organ. We now know that the insulin receptor is present throughout the brain and serves important functions in whole-body metabolism and brain function. Brain insulin signaling is involved not only in brain homeostatic processes but also neuropathological processes such as cognitive decline and Alzheimer's disease. Scope of review In this review, we provide an overview of insulin signaling within the brain and the metabolic impact of brain insulin resistance and discuss Alzheimer's disease, one of the neurologic diseases most closely associated with brain insulin resistance. Major conclusions While brain insulin signaling plays only a small role in central nervous system glucose regulation, it has a significant impact on the brain's metabolic health. Normal insulin signaling is important for mitochondrial functioning and normal food intake. Brain insulin resistance contributes to obesity and may also play an important role in neurodegeneration. Insulin is an important regulator of brain metabolism. Brain insulin signaling helps regulate whole body metabolism. Brain insulin signaling may play an important role in the pathogenesis of Alzheimer's disease.
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35
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Kulkarni VV, Anand A, Herr JB, Miranda C, Vogel MC, Maday S. Synaptic activity controls autophagic vacuole motility and function in dendrites. J Cell Biol 2021; 220:211926. [PMID: 33783472 PMCID: PMC8020715 DOI: 10.1083/jcb.202002084] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 01/06/2021] [Accepted: 03/04/2021] [Indexed: 02/07/2023] Open
Abstract
Macroautophagy (hereafter “autophagy”) is a lysosomal degradation pathway that is important for learning and memory, suggesting critical roles for autophagy at the neuronal synapse. Little is known, however, about the molecular details of how autophagy is regulated with synaptic activity. Here, we used live-cell confocal microscopy to define the autophagy pathway in primary hippocampal neurons under various paradigms of synaptic activity. We found that synaptic activity regulates the motility of autophagic vacuoles (AVs) in dendrites. Stimulation of synaptic activity dampens AV motility, whereas silencing synaptic activity induces AV motility. Activity-dependent effects on dendritic AV motility are local and reversible. Importantly, these effects are compartment specific, occurring in dendrites and not in axons. Most strikingly, synaptic activity increases the presence of degradative autolysosomes in dendrites and not in axons. On the basis of our findings, we propose a model whereby synaptic activity locally controls AV dynamics and function within dendrites that may regulate the synaptic proteome.
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Affiliation(s)
- Vineet Vinay Kulkarni
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Anip Anand
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Jessica Brandt Herr
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Christina Miranda
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Maria Chalokh Vogel
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
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36
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Bensalem J, Fourrier C, Hein LK, Hassiotis S, Proud CG, Sargeant TJ. Inhibiting mTOR activity using AZD2014 increases autophagy in the mouse cerebral cortex. Neuropharmacology 2021; 190:108541. [PMID: 33794244 DOI: 10.1016/j.neuropharm.2021.108541] [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: 10/04/2020] [Revised: 03/16/2021] [Accepted: 03/24/2021] [Indexed: 01/18/2023]
Abstract
Autophagy is a catabolic process that collects and degrades damaged or unwanted cellular materials such as protein aggregates. Defective brain autophagy has been linked to diseases such as Alzheimer's disease. Autophagy is regulated by the protein kinase mTOR (mechanistic target of rapamycin). Although already demonstrated in vitro, it remains contentious whether inhibiting mTOR can enhance autophagy in the brain. To address this, mice were intraperitoneally injected with the mTOR inhibitor AZD2014 for seven days. mTOR complex 1 (mTORC1) activity was decreased in liver and brain. Autophagic activity was increased by AZD2014 in both organs, as measured by immunoblotting for LC3 (microtubule-associated proteins-1A/1B light chain 3B) and measurement of autophagic flux in the cerebral cortex of transgenic mice expressing the EGFP-mRFP-LC3B transgene. mTOR activity was shown to correlate with changes in LC3. Thus, we show it is possible to promote autophagy in the brain using AZD2014, which will be valuable in tackling conditions associated with defective autophagy, especially neurodegeneration.
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Affiliation(s)
- Julien Bensalem
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Célia Fourrier
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Leanne K Hein
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Sofia Hassiotis
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Christopher G Proud
- Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Timothy J Sargeant
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia.
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37
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Lalo U, Pankratov Y. Astrocytes as Perspective Targets of Exercise- and Caloric Restriction-Mimetics. Neurochem Res 2021; 46:2746-2759. [PMID: 33677759 PMCID: PMC8437875 DOI: 10.1007/s11064-021-03277-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/20/2022]
Abstract
Enhanced mental and physical activity can have positive effects on the function of aging brain, both in the experimental animals and human patients, although cellular mechanisms underlying these effects are currently unclear. There is a growing evidence that pre-clinical stage of many neurodegenerative diseases involves changes in interactions between astrocytes and neurons. Conversely, astrocytes are strategically positioned to mediate the positive influence of physical activity and diet on neuronal function. Thus, development of therapeutic agents which could improve the astroglia-neuron communications in ageing brain is of crucial importance. Recent advances in studies of cellular mechanisms of brain longevity suggest that astrocyte-neuron communications have a vital role in the beneficial effects of caloric restriction, physical exercise and their pharmacological mimetics on synaptic homeostasis and cognitive function. In particular, our recent data indicate that noradrenaline uptake inhibitor atomoxetine can enhance astrocytic Ca2+-signaling and astroglia-driven modulation of synaptic plasticity. Similar effects were exhibited by caloric restriction-mimetics metformin and resveratrol. The emerged data also suggest that astrocytes could be involved in the modulatory action of caloric restriction and its mimetics on neuronal autophagy. Still, the efficiency of astrocyte-targeting compounds in preventing age-related cognitive decline is yet to be fully explored, in particular in the animal models of neurodegenerative diseases and autophagy impairment.
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Affiliation(s)
- Ulyana Lalo
- School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russia.,School of Life Sciences, University of Warwick, Coventry, UK
| | - Yuriy Pankratov
- School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russia. .,School of Life Sciences, University of Warwick, Coventry, UK.
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38
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Lejault P, Moruno-Manchon JF, Vemu SM, Honarpisheh P, Zhu L, Kim N, Urayama A, Monchaud D, McCullough LD, Tsvetkov AS. Regulation of autophagy by DNA G-quadruplexes. Autophagy 2020; 16:2252-2259. [PMID: 32420812 DOI: 10.1080/15548627.2020.1769991] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Guanine-rich DNA strands can form secondary structures known as G-quadruplexes (G4-DNA or G4s). G4-DNA is important for the regulation of replication and transcription. We recently showed that the expression of Atg7, a gene that is critical for macroautophagy/autophagy, is controlled by G4-DNA in neurons. We demonstrated that the transcription factor SUB1/PC4 and the G4-DNA-specific antibody HF2 bind to a putative G4-DNA motif located in the Atg7 gene. Stabilizing G4-DNA with the G4-ligand pyridostatin (PDS) downregulates Atg7 expression in neurons. Here, we further investigated how G4-DNA in the Atg7 gene is stabilized by PDS. We show that PDS can form 1:1 and 2:1 complexes with the Atg7's G4. We also demonstrate that PDS downregulates the ATG7 protein and the expression of Atg7 in astrocytes as well as in neurons. Together with our previous findings, these data establish a novel G4-DNA-associated mechanism of autophagy regulation at a transcriptional level in neurons and astrocytes.
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Affiliation(s)
- Pauline Lejault
- UBFC Dijon, Institut De Chimie Moléculaire (ICMUB) , Dijon, France
| | - Jose F Moruno-Manchon
- Department of Neurology, The University of Texas McGovern Medical School at Houston , Houston, TX, USA
| | - Sree M Vemu
- Summer Research Program, the University of Texas Medical School at Houston , TX, USA
| | - Pedram Honarpisheh
- Department of Neurology, The University of Texas McGovern Medical School at Houston , Houston, TX, USA.,The University of Texas Graduate School of Biomedical Sciences , Houston, TX, USA
| | - Liang Zhu
- Biostatistics and Epidemiology Research Design Core Center for Clinical and Translational Sciences, The University of Texas McGovern Medical School at Houston , Houston, TX, USA.,Department of Internal Medicine, The University of Texas McGovern Medical School at Houston , Houston, TX, USA
| | - Nayun Kim
- The University of Texas Graduate School of Biomedical Sciences , Houston, TX, USA.,Department of Microbiology and Molecular Genetics, The University of Texas McGovern Medical School at Houston , TX
| | - Akihiko Urayama
- Department of Neurology, The University of Texas McGovern Medical School at Houston , Houston, TX, USA.,The University of Texas Graduate School of Biomedical Sciences , Houston, TX, USA
| | - David Monchaud
- UBFC Dijon, Institut De Chimie Moléculaire (ICMUB) , Dijon, France
| | - Louise D McCullough
- Department of Neurology, The University of Texas McGovern Medical School at Houston , Houston, TX, USA.,The University of Texas Graduate School of Biomedical Sciences , Houston, TX, USA
| | - Andrey S Tsvetkov
- Department of Neurology, The University of Texas McGovern Medical School at Houston , Houston, TX, USA.,The University of Texas Graduate School of Biomedical Sciences , Houston, TX, USA.,UTHealth Consortium on Aging, The University of Texas McGovern Medical School , Houston, TX, USA
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39
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Ortiz-Rodriguez A, Arevalo MA. The Contribution of Astrocyte Autophagy to Systemic Metabolism. Int J Mol Sci 2020; 21:E2479. [PMID: 32260050 PMCID: PMC7177973 DOI: 10.3390/ijms21072479] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/20/2020] [Accepted: 04/02/2020] [Indexed: 12/15/2022] Open
Abstract
Autophagy is an essential mechanism to maintain cellular homeostasis. Besides its role in controlling the quality of cytoplasmic components, it participates in nutrient obtaining and lipid mobilization under stressful conditions. Furthermore, autophagy is involved in the regulation of systemic metabolism as its blockade in hypothalamic neurons can affect the central regulation of metabolism and impact body energy balance. Moreover, hypothalamic autophagy can be altered during obesity, one of the main alterations of metabolism nowadays. In this review, we focus on the role of astrocytes, essential cells for brain homeostasis, which represent key metabolic regulators. Astrocytes can sense metabolic signals in the hypothalamus and modulate systemic functions as glucose homeostasis and feeding response. Moreover, the response of astrocytes to obesity has been widely studied. Astrocytes are important mediators of brain inflammation and can be affected by increased levels of saturated fatty acids associated with obesity. Although autophagy plays important roles for astrocyte homeostasis and functioning, the contribution of astrocyte autophagy to systemic metabolism has not been analyzed yet. Furthermore, how obesity can impact astrocyte autophagy is poorly understood. More studies are needed in order to understand the contribution of astrocyte autophagy to metabolism.
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Affiliation(s)
- Ana Ortiz-Rodriguez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain;
| | - Maria-Angeles Arevalo
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain;
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
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40
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Uzor NE, McCullough LD, Tsvetkov AS. Peroxisomal Dysfunction in Neurological Diseases and Brain Aging. Front Cell Neurosci 2020; 14:44. [PMID: 32210766 PMCID: PMC7075811 DOI: 10.3389/fncel.2020.00044] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/18/2020] [Indexed: 12/17/2022] Open
Abstract
Peroxisomes exist in most cells, where they participate in lipid metabolism, as well as scavenging the reactive oxygen species (ROS) that are produced as by-products of their metabolic functions. In certain tissues such as the liver and kidneys, peroxisomes have more specific roles, such as bile acid synthesis in the liver and steroidogenesis in the adrenal glands. In the brain, peroxisomes are critically involved in creating and maintaining the lipid content of cell membranes and the myelin sheath, highlighting their importance in the central nervous system (CNS). This review summarizes the peroxisomal lifecycle, then examines the literature that establishes a link between peroxisomal dysfunction, cellular aging, and age-related disorders that affect the CNS. This review also discusses the gap of knowledge in research on peroxisomes in the CNS.
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Affiliation(s)
- Ndidi-Ese Uzor
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, TX, United States
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Louise D. McCullough
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, United States
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX, United States
- UTHealth Consortium on Aging, University of Texas McGovern Medical School, Houston, TX, United States
| | - Andrey S. Tsvetkov
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, TX, United States
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, United States
- UTHealth Consortium on Aging, University of Texas McGovern Medical School, Houston, TX, United States
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