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Bresgen N, Kovacs M, Lahnsteiner A, Felder TK, Rinnerthaler M. The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective. Biomolecules 2023; 13:912. [PMID: 37371492 DOI: 10.3390/biom13060912] [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: 03/13/2023] [Revised: 05/22/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.
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Affiliation(s)
- Nikolaus Bresgen
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Melanie Kovacs
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Angelika Lahnsteiner
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Thomas Klaus Felder
- Department of Laboratory Medicine, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Mark Rinnerthaler
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
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Ibrahim WW, Kamel AS, Wahid A, Abdelkader NF. Dapagliflozin as an autophagic enhancer via LKB1/AMPK/SIRT1 pathway in ovariectomized/D-galactose Alzheimer's rat model. Inflammopharmacology 2022; 30:2505-2520. [PMID: 35364737 PMCID: PMC9700568 DOI: 10.1007/s10787-022-00973-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/05/2022] [Indexed: 12/17/2022]
Abstract
Autophagy and mitochondrial deficits are characteristics of early phase of Alzheimer's disease (AD). Sodium-glucose cotransporter-2 inhibitors have been nominated as a promising class against AD hallmarks. However, there are no available data yet to discuss the impact of gliflozins on autophagic pathways in AD. Peripherally, dapagliflozin's (DAPA) effect is mostly owed to autophagic signals. Thus, the goal of this study is to screen the power of DAPA centrally on LKB1/AMPK/SIRT1/mTOR signaling in the ovariectomized/D-galactose (OVX/D-Gal) rat model. Animals were arbitrarily distributed between 5 groups; the first group undergone sham operation, while remaining groups undergone OVX followed by D-Gal (150 mg/kg/day; i.p.) for 70 days. After 6 weeks, the third, fourth, and fifth groups received DAPA (1 mg/kg/day; p.o.); concomitantly with the AMPK inhibitor dorsomorphin (DORSO, 25 µg/rat, i.v.) in the fourth group and the SIRT1 inhibitor EX-527 (10 µg/rat, i.v.) in the fifth group. DAPA mitigated cognitive deficits of OVX/D-Gal rats, as mirrored in neurobehavioral task with hippocampal histopathological examination and immunohistochemical aggregates of p-Tau. The neuroprotective effect of DAPA was manifested by elevation of energy sensors; AMP/ATP ratio and LKB1/AMPK protein expressions along with autophagic markers; SIRT1, Beclin1, and LC3B expressions. Downstream the latter, DAPA boosted mTOR and mitochondrial function; TFAM, in contrary lessened BACE1. Herein, DORSO or EX-527 co-administration prohibited DAPA's actions where DORSO elucidated DAPA's direct effect on LKB1 while EX-527 mirrored its indirect effect on SIRT1. Therefore, DAPA implied its anti-AD effect, at least in part, via boosting hippocampal LKB1/AMPK/SIRT1/mTOR signaling in OVX/D-Gal rat model.
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Affiliation(s)
- Weam W Ibrahim
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo, 11562, Egypt
| | - Ahmed S Kamel
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo, 11562, Egypt
| | - Ahmed Wahid
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Noha F Abdelkader
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo, 11562, Egypt.
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Lee J, Kim HJ. Normal Aging Induces Changes in the Brain and Neurodegeneration Progress: Review of the Structural, Biochemical, Metabolic, Cellular, and Molecular Changes. Front Aging Neurosci 2022; 14:931536. [PMID: 35847660 PMCID: PMC9281621 DOI: 10.3389/fnagi.2022.931536] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/13/2022] [Indexed: 11/30/2022] Open
Abstract
Aging is accompanied by many changes in brain and contributes to progressive cognitive decline. In contrast to pathological changes in brain, normal aging brain changes have relatively mild but important changes in structural, biochemical and molecular level. Representatively, aging associated brain changes include atrophy of tissues, alteration in neurotransmitters and damage accumulation in cellular environment. These effects have causative link with age associated changes which ultimately results in cognitive decline. Although several evidences were found in normal aging changes of brain, it is not clearly integrated. Figuring out aging related changes in brain is important as aging is the process that everyone goes through, and comprehensive understanding may help to progress further studies. This review clarifies normal aging brain changes in an asymptotic and comprehensive manner, from a gross level to a microscopic and molecular level, and discusses potential approaches to seek the changes with cognitive decline.
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Affiliation(s)
- Jiseon Lee
- Department of Neurology, Hanyang University Hospital, Seoul, South Korea
| | - Hee-Jin Kim
- Department of Neurology, Hanyang University Hospital, Seoul, South Korea
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Breedon SA, Gupta A, Storey KB. Regulation of Apoptosis and Autophagy During Anoxia in the Freshwater Crayfish, Faxonius virilis. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:626-639. [PMID: 35567599 DOI: 10.1007/s10126-022-10132-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
The ability of an animal to survive prolonged periods of oxygen deprivation is a critical area of study, both in terms of its importance to better understanding the physiology of these incredible animals and to its potential applicability to medical fields. The freshwater crayfish, Faxonius virilis, is one such animal capable of resisting anoxia, but it remains understudied and much of the metabolic mechanisms underlying this anoxia tolerance remain largely unprofiled. This study examines the activity and regulation of apoptosis and autophagy in F. virilis in response to 20-h anoxia. Apoptosis signaling was assessed through pro- and anti-apoptosis targets, whereas autophagy was assessed via expression response of multiple autophagy proteins. An anoxia-triggered, tissue-specific result arose, potentially based on the importance of individual organ integrity through hypometabolism. Tail muscle, which showed increased expression profiles of all three target groups, contrasted with hepatopancreas, which appeared to not be susceptible to either apoptotic or autophagic signaling during anoxia. This is likely due to the importance of the hepatopancreas, given that apoptosis or autophagy of this organ at any significant level could be fatal to the organism. The data provides a comprehensive overview of the responses and integration of multiple stress-responsive signaling pathways in F. virilis that provide a novel contribution to our understanding of pro-survival mechanisms supporting invertebrate anoxia resistance.
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Affiliation(s)
- Sarah A Breedon
- Institute of Biochemistry and Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Aakriti Gupta
- Institute of Biochemistry and Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University, Ottawa, ON, Canada.
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Zhang W, Yang Y, Xiang Z, Cheng J, Yu Z, Wang W, Hu L, Ma F, Deng Y, Jin Z, Hu X. MRTF-A-mediated protection against amyloid-β-induced neuronal injury correlates with restoring autophagy via miR-1273g-3p/mTOR axis in Alzheimer models. Aging (Albany NY) 2022; 14:4305-4325. [PMID: 35604830 PMCID: PMC9186769 DOI: 10.18632/aging.203883] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 12/07/2021] [Indexed: 11/25/2022]
Abstract
Myocardia-Related Transcription Factors-A (MRTF-A), which is enriched in the hippocampus and cerebral cortex, has been shown to have a protective function against ischemia hypoxia-induced neuronal apoptosis. However, the function of MRTF-A on β-amyloid peptide (Aβ)-induced neurotoxicity and autophagy dysfunction in Alzheimer's disease is still unclear. This study shows that the expression of MRTF-A in the hippocampus of Tg2576 transgenic mice is reduced, and the overexpression of MRTF-A mediated by lentiviral vectors carrying MRTF-A significantly reduces the accumulation of hippocampal β-amyloid peptide and reduces cognition defect. Overexpression of MRTF-A inhibits neuronal apoptosis, increases the protein levels of microtubule-associated protein 1 light chain 3-II (MAP1LC3/LC3-II) and Beclin1, reduces the accumulation of SQSTM1/p62 protein, and promotes autophagosomes-Lysosomal fusion in vivo and in vitro. Microarray analysis and bioinformatics analysis show that MRTF-A reverses Aβ-induced autophagy impairment by up-regulating miR-1273g-3p level leading to negative regulation of the mammalian target of rapamycin (mTOR), which is confirmed in Aβ1-42-treated SH-SY5Y cells. Further, overexpression of MRTF-A reduces Aβ1-42-induced neuronal apoptosis. And the effect was abolished by miR-1273g-3p inhibitor or MHY1485 (mTOR agonist), indicating that the protection of MRTF-A on neuronal damage is through targeting miR-1273g-3p/mTOR axis. Targeting this signaling may be a promising approach to protect against Aβ-induced neuronal injury.
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Affiliation(s)
- Wei Zhang
- Affiliated Wuhan Resources and Wisco General Hospital, University of Science and Technology, Wuhan, Hubei, China
| | - Yuewang Yang
- College of Pharmacy, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Zifei Xiang
- College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Jinping Cheng
- Affiliated Wuhan Resources and Wisco General Hospital, University of Science and Technology, Wuhan, Hubei, China
| | - Zhijun Yu
- College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Wen Wang
- Affiliated Wuhan Resources and Wisco General Hospital, University of Science and Technology, Wuhan, Hubei, China
| | - Ling Hu
- College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Fuyun Ma
- College of Pharmacy, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Youping Deng
- Bioinformatics Core Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
| | - Zhigang Jin
- Affiliated Wuhan Resources and Wisco General Hospital, University of Science and Technology, Wuhan, Hubei, China
| | - Xiamin Hu
- College of Pharmacy, Shanghai University of Medicine and Health Sciences, Shanghai, China
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Li LR, Sethi G, Zhang X, Liu CL, Huang Y, Liu Q, Ren BX, Tang FR. The neuroprotective effects of icariin on ageing, various neurological, neuropsychiatric disorders, and brain injury induced by radiation exposure. Aging (Albany NY) 2022; 14:1562-1588. [PMID: 35165207 PMCID: PMC8876913 DOI: 10.18632/aging.203893] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/08/2022] [Indexed: 11/25/2022]
Abstract
Epimedium brevicornum Maxim, a Traditional Chinese Medicine, has been used for the treatment of impotence, sinew and bone disorders, “painful impediment caused by wind-dampness,” numbness, spasms, hypertension, coronary heart disease, menopausal syndrome, bronchitis, and neurasthenia for many years in China. Recent animal experimental studies indicate that icariin, a major bioactive component of epimedium may effectively treat Alzheimer’s disease, cerebral ischemia, depression, Parkinson’s disease, multiple sclerosis, as well as delay ageing. Our recent study also suggested that epimedium extract could exhibit radio-neuro-protective effects and prevent ionizing radiation-induced impairment of neurogenesis. This paper reviewed the pharmacodynamics of icariin in treating different neurodegenerative and neuropsychiatric diseases, ageing, and radiation-induced brain damage. The relevant molecular mechanisms and its anti-neuroinflammatory, anti-apoptotic, anti-oxidant, as well as pro-neurogenesis roles were also discussed.
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Affiliation(s)
- Ling Rui Li
- The School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou 434023, Hubei, China
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117600, Singapore
| | - Xing Zhang
- The School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou 434023, Hubei, China
| | - Cui Liu Liu
- The School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou 434023, Hubei, China
| | - Yan Huang
- The School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou 434023, Hubei, China
| | - Qun Liu
- The School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou 434023, Hubei, China
| | - Bo Xu Ren
- The School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou 434023, Hubei, China
| | - Feng Ru Tang
- Radiation Physiology Lab, Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore 138602, Singapore
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Zheng J, Hu S, Wang J, Zhang X, Yuan D, Zhang C, Liu C, Wang T, Zhou Z. Icariin improves brain function decline in aging rats by enhancing neuronal autophagy through the AMPK/mTOR/ULK1 pathway. PHARMACEUTICAL BIOLOGY 2021; 59:183-191. [PMID: 33556283 PMCID: PMC8871627 DOI: 10.1080/13880209.2021.1878238] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
CONTEXT Icariin (ICA) is the main active ingredient of Epimedium brevicornu Maxim (Berberidaceae), which is used in the immune, reproductive, neuroendocrine systems, and anti-aging. OBJECTIVE To evaluate the effect of ICA on natural aging rat. MATERIALS AND METHODS 16-month-old Sprague-Dawley (SD) rats were randomly divided into aging, low and high-dose ICA groups (n = 8); 6-month-old rats were taken as the adult control (n = 8). Rats were fed regular feed (aging and adult control) or feed containing ICA (ICA 2 and 6 mg/kg group) for 4 months. HE and Nissl staining were used to assess pathological changes. Western blot was used to test the expression of autophagy (LC3B, p62, Atg5, Beclin1) and p-AMPK, p-mTOR and p-ULK1 (ser 757). Immunofluorescence was used to detect the co-localization of LC3 and neurons. RESULTS ICA improved neuronal degeneration associated with aging and increased the staining of Nissl bodies. Western blot showed that ICA up-regulated autophagy-related proteins LC3B (595%), Beclin1 (73.5%), p-AMPK (464%) protein (p < 0.05 vs. 20 M) in the cortex and hippocampus of aging rats, down-regulated the expression of p62 (56.9%), p-mTOR (53%) and p-ULK1 (ser 757) (65.4%) protein (p < 0.05 vs. 20 M). Immunofluorescence showed that the fluorescence intensity of LC3 decreased in the aging rat brain, but increased and mainly co-localized with neurons after ICA intervention. CONCLUSIONS Further research needs to verify the expression changes of AMPK/mTOR/ULK1 and the improvement effect of ICA in elderly. These results will further accelerate the applications of ICA and the treatment for senescence.
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Affiliation(s)
- Jie Zheng
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Shanshan Hu
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Jinxin Wang
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Xulan Zhang
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Ding Yuan
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Changcheng Zhang
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Chaoqi Liu
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
| | - Ting Wang
- Department of Pharmacy, College of Medicine, New Drug Innovation and Development Institute, Wuhan University of Science and Technology, Wuhan, Hubei Province, China
- Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei Province, China
- CONTACT Ting Wang Department of Pharmacy, College of Medicine, New Drug Innovation and Development Institute, Wuhan University of Science and Technology, Wuhan, Hubei Province, China
| | - Zhiyong Zhou
- Medical College of China Three Gorges University, Yichang, P. R. Chinas
- Zhiyong Zhou Medical College of China, Three Gorges University, 8 University Road, Yichang 443002, Hubei, China
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Nesci S, Trombetti F, Pagliarani A, Ventrella V, Algieri C, Tioli G, Lenaz G. Molecular and Supramolecular Structure of the Mitochondrial Oxidative Phosphorylation System: Implications for Pathology. Life (Basel) 2021; 11:242. [PMID: 33804034 PMCID: PMC7999509 DOI: 10.3390/life11030242] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 02/07/2023] Open
Abstract
Under aerobic conditions, mitochondrial oxidative phosphorylation (OXPHOS) converts the energy released by nutrient oxidation into ATP, the currency of living organisms. The whole biochemical machinery is hosted by the inner mitochondrial membrane (mtIM) where the protonmotive force built by respiratory complexes, dynamically assembled as super-complexes, allows the F1FO-ATP synthase to make ATP from ADP + Pi. Recently mitochondria emerged not only as cell powerhouses, but also as signaling hubs by way of reactive oxygen species (ROS) production. However, when ROS removal systems and/or OXPHOS constituents are defective, the physiological ROS generation can cause ROS imbalance and oxidative stress, which in turn damages cell components. Moreover, the morphology of mitochondria rules cell fate and the formation of the mitochondrial permeability transition pore in the mtIM, which, most likely with the F1FO-ATP synthase contribution, permeabilizes mitochondria and leads to cell death. As the multiple mitochondrial functions are mutually interconnected, changes in protein composition by mutations or in supercomplex assembly and/or in membrane structures often generate a dysfunctional cascade and lead to life-incompatible diseases or severe syndromes. The known structural/functional changes in mitochondrial proteins and structures, which impact mitochondrial bioenergetics because of an impaired or defective energy transduction system, here reviewed, constitute the main biochemical damage in a variety of genetic and age-related diseases.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy; (F.T.); (V.V.); (C.A.)
| | - Fabiana Trombetti
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy; (F.T.); (V.V.); (C.A.)
| | - Alessandra Pagliarani
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy; (F.T.); (V.V.); (C.A.)
| | - Vittoria Ventrella
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy; (F.T.); (V.V.); (C.A.)
| | - Cristina Algieri
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy; (F.T.); (V.V.); (C.A.)
| | - Gaia Tioli
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, 40138 Bologna, Italy;
| | - Giorgio Lenaz
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, 40138 Bologna, Italy;
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Sarmah DT, Bairagi N, Chatterjee S. Tracing the footsteps of autophagy in computational biology. Brief Bioinform 2020; 22:5985288. [PMID: 33201177 PMCID: PMC8293817 DOI: 10.1093/bib/bbaa286] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/11/2022] Open
Abstract
Autophagy plays a crucial role in maintaining cellular homeostasis through the degradation of unwanted materials like damaged mitochondria and misfolded proteins. However, the contribution of autophagy toward a healthy cell environment is not only limited to the cleaning process. It also assists in protein synthesis when the system lacks the amino acids’ inflow from the extracellular environment due to diet consumptions. Reduction in the autophagy process is associated with diseases like cancer, diabetes, non-alcoholic steatohepatitis, etc., while uncontrolled autophagy may facilitate cell death. We need a better understanding of the autophagy processes and their regulatory mechanisms at various levels (molecules, cells, tissues). This demands a thorough understanding of the system with the help of mathematical and computational tools. The present review illuminates how systems biology approaches are being used for the study of the autophagy process. A comprehensive insight is provided on the application of computational methods involving mathematical modeling and network analysis in the autophagy process. Various mathematical models based on the system of differential equations for studying autophagy are covered here. We have also highlighted the significance of network analysis and machine learning in capturing the core regulatory machinery governing the autophagy process. We explored the available autophagic databases and related resources along with their attributes that are useful in investigating autophagy through computational methods. We conclude the article addressing the potential future perspective in this area, which might provide a more in-depth insight into the dynamics of autophagy.
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Affiliation(s)
| | - Nandadulal Bairagi
- Centre for Mathematical Biology and Ecology, Department of Mathematics, Jadavpur University, Kolkata, India
| | - Samrat Chatterjee
- Translational Health Science and Technology Institute, Faridabad, India
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10
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Zeng Z, Liang J, Wu L, Zhang H, Lv J, Chen N. Exercise-Induced Autophagy Suppresses Sarcopenia Through Akt/mTOR and Akt/FoxO3a Signal Pathways and AMPK-Mediated Mitochondrial Quality Control. Front Physiol 2020; 11:583478. [PMID: 33224037 PMCID: PMC7667253 DOI: 10.3389/fphys.2020.583478] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/10/2020] [Indexed: 12/21/2022] Open
Abstract
Exercise training is one of the most effective interventional strategies for sarcopenia in aged people. Nevertheless, the underlying mechanisms are not well recognized. Increasing studies have reported abnormal regulation of autophagy in aged skeletal muscle. Our current study aims to explore the efficiency of exercise interventions, including treadmill exercise, resistance exercise, alternating exercise with treadmill running and resistance exercise, and voluntary wheel running, on 21-month-old rats with sarcopenia and to detect the underlying mechanisms. Results showed the declined mass of gastrocnemius muscle with deficient autophagy and excessive apoptosis as a result of up-regulated Atrogin-1 and MuRF1, declined Beclin1 level and LC3-II/LC3-I ratio, accumulated p62, increased Bax, and reduced Bcl-2 levels, and also exhibited a defective mitochondrial quality control due to declined PGC-1α, Mfn2, Drp1, and PINK1 levels. However, 12-week exercise interventions suppressed the decline in mass loss of skeletal muscle, accompanied by down-regulated Atrogin-1 and MuRF1, increased Beclin1 level, improved LC3-II/LC3-I ratio, declined p62 level, and reduced Bax and increased Bcl-2 level, as well as enhanced mitochondrial function due to the increased PGC-1α, Mfn2, Drp1, and PINK1 levels. Moreover, exercise interventions also down-regulated the phosphorylation of Akt, mTOR, and FoxO3a, and up-regulated phosphorylated AMPK to regulate the functional status of autophagy and mitochondrial quality control. Therefore, exercise-induced autophagy is beneficial for remedying sarcopenia by modulating Akt/mTOR and Akt/FoxO3a signal pathways and AMPK-mediated mitochondrial quality control, and resistance exercise exhibits the best interventional efficiency.
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Affiliation(s)
- Zhengzhong Zeng
- Graduate School, Wuhan Sports University, Wuhan, China.,Sports Institute, Chongqing University of Arts and Sciences, Chongqing, China
| | - Jiling Liang
- Graduate School, Wuhan Sports University, Wuhan, China
| | - Liangwen Wu
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Exercise Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan, China
| | - Hu Zhang
- Graduate School, Wuhan Sports University, Wuhan, China
| | - Jun Lv
- Graduate School, Wuhan Sports University, Wuhan, China
| | - Ning Chen
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Exercise Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan, China
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11
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Yuan H, Jiang C, Zhao J, Zhao Y, Zhang Y, Xu Y, Gao X, Guo L, Liu Y, Liu K, Xu B, Sun G. Euxanthone Attenuates Aβ1–42-Induced Oxidative Stress and Apoptosis by Triggering Autophagy. J Mol Neurosci 2018; 66:512-523. [DOI: 10.1007/s12031-018-1175-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 09/14/2018] [Indexed: 12/26/2022]
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12
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Bi S, Wang H, Kuang W. Stem cell rejuvenation and the role of autophagy in age retardation by caloric restriction: An update. Mech Ageing Dev 2018; 175:46-54. [PMID: 30031008 DOI: 10.1016/j.mad.2018.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 07/17/2018] [Accepted: 07/17/2018] [Indexed: 12/14/2022]
Abstract
Stem cells being pluripotent in nature can differentiate into a wide array of specific cells and asymmetrically divide to produce new ones but may undergo aging by themselves. Aging has both quantitative and qualitative effects on stem cells, and could eventually restrain them from replenishing into progenitor cells. Reactive oxygen species (ROS) accumulated in the aging cells could not only block the cell cycle but also affect autophagy by damaging the mitochondria. Autophagy could eliminate redundant production of ROS in aging stem cells and helps to maintain the proliferation capacity by restraining the expression of p16INK4a. Current studies showed that improving autophagy could restore the regenerative ability of aging stem cells. Therefore, it is important for an organism to maintain the appropriate autophagy. Caloric restriction (CR) was shown to retard the stem cell aging by a certain basic level of autophagy, suggesting that CR was an effective way to extend longevity in mammals. However, little is known about the underlying mechanisms. In this review, we tried to explore the molecular mechanisms on how CR induces appropriate autophagy to restore aging stem cell regenerative ability.
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Affiliation(s)
- Shanrong Bi
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Hanyu Wang
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Weihong Kuang
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China.
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13
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Autophagy induction by hispidulin provides protection against sevoflurane-induced neuronal apoptosis in aged rats. Biomed Pharmacother 2018; 98:460-468. [DOI: 10.1016/j.biopha.2017.12.097] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 12/18/2022] Open
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14
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Ke S, Lai Y, Zhou T, Li L, Wang Y, Ren L, Ye S. Molybdenum Disulfide Nanoparticles Resist Oxidative Stress-Mediated Impairment of Autophagic Flux and Mitigate Endothelial Cell Senescence and Angiogenic Dysfunctions. ACS Biomater Sci Eng 2018; 4:663-674. [PMID: 33418754 DOI: 10.1021/acsbiomaterials.7b00714] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The impairment of autophagy involves oxidative stress-induced cellular senescence, leading to endothelial dysfunctions and the onset of cardiovascular diseases. As molybdenum disulfide nanoparticles (MoS2 NPs), representative transition metal dichacogenide materials, have great potential as a multifunctional therapeutic agent against various disorders, the present study aimed to investigate whether MoS2 NPs prevents hydrogen peroxide (H2O2)-induced endothelial senescence by modulating autophagic process. Our results showed that pretreatment with MoS2 NPs inhibited H2O2-induced endothelial senescence and improved endothelial functions. Exposure of H2O2 increased p62 level and blocked the fusion of autophagosomes with lysosomes, indicating of impaired autophagic flux in senescent endothelial cells. However, MoS2 NPs pretreatment efficiently suppressed cellular senescence through triggering autophagy and resisting impaired autophagic flux. Furthermore, the genetic inhibition of autophagy by siRNA against Beclin 1 or ATG-5 directly abrogated the protective action of MoS2 NPs on endothelial cells against H2O2-induced senescence.Thus, these results suggested that MoS2 NPs rescue endothelial cells from H2O2-induced senescence by improving autophagic flux, and provide valuable information for the rational design of MoS2-based nanomaterials for therapeutic use in senescence-related diseases.
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Affiliation(s)
- Sunkui Ke
- Department of Thoracic Surgery, Zhongshan Hospital of Xiamen University, Xiamen 361004, P. R. China
| | - Youlin Lai
- Department of Obstetrics, Xiamen Maternity and Care Hospital, Xiamen 361000, P. R. China
| | - Tong Zhou
- Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, P. R. China
| | - Lihuang Li
- Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, P. R. China
| | - Yange Wang
- Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, P. R. China
| | - Lei Ren
- Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, P. R. China
| | - Shefang Ye
- Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, P. R. China
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15
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Takahashi K, Nakamura H, Ozawa H, Hashimoto S, Iijima N, Higo S, Watanabe H, Mochizuki Y, Takai S. Effectiveness of Radiofrequency Hyperthermia for Treating Cartilage in Guinea Pigs with Primary Osteoarthritis. Cartilage 2018; 9:71-79. [PMID: 29219022 PMCID: PMC5724668 DOI: 10.1177/1947603516678974] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective Autophagy was reported to be essential for maintaining chondrocyte function, and reduced autophagy leads to osteoarthritis (OA). Previous studies showed involvement of heat shock stress in the control of autophagy in cells. This study sought to investigate the effect of hyperthermia on the expression of autophagy-related proteins in articular cartilage and the progression of naturally occurring OA in Hartley guinea pigs. Design Radiofrequency pulses of 13.56 MHz were applied to the animals' knees for 20 minutes to induce hyperthermia. The knee joints were resected at 8 hours, 24 hours, 72 hours, 7 days, and 6 months after hyperthermia. Serial sections of knees were examined for histopathological changes. The expression levels of Unc-51-like kinase 1 (ULK1) and Beclin1 were analyzed by immunohistochemistry. Results Analysis of the distribution of positive cells showed that, in cases of moderate OA, ULK1 and Beclin1 expression levels were significantly decreased in the superficial zone (SZ) and middle zone (MZ) ( P < 0.01) compared with normal cartilage. Seven days after exposure to radiofrequency waves, expression levels of ULK1 and Beclin1 were augmented in the SZ in animals with mild OA. The severity of cartilage degradation was significantly reduced ( P < 0.01) in the radiofrequency-treated knees versus the untreated knees. Conclusions This study showed that heat stimulation enhanced autophagy in healthy knee chondrocytes and chondrocytes in knees with mild OA. The study also showed that long-term periodic application of hyperthermia suppresses aging-related progression of OA. The activation of autophagy by radiofrequency hyperthermia may be an effective therapeutic approach for osteoarthritis.
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Affiliation(s)
- Kenji Takahashi
- Department of Orthopaedic Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan,Kenji Takahashi, Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.
| | - Hiroshi Nakamura
- Department of Orthopaedic Surgery, International University of Health and Welfare Hospital, Nasu-shiobara, Tochigi, Japan
| | - Hitoshi Ozawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Sanshiro Hashimoto
- Minami-Shinjuku Orthopaedic Rehabilitation Clinic, Shibuya-ku, Tokyo, Japan
| | - Norio Iijima
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Shimpei Higo
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Hiroshi Watanabe
- Department of Orthopaedic Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Yusuke Mochizuki
- Department of Orthopaedic Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Shinro Takai
- Department of Orthopaedic Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
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16
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Feng Z, Hanson RW, Berger NA, Trubitsyn A. Reprogramming of energy metabolism as a driver of aging. Oncotarget 2017; 7:15410-20. [PMID: 26919253 PMCID: PMC4941250 DOI: 10.18632/oncotarget.7645] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 02/11/2016] [Indexed: 12/15/2022] Open
Abstract
Aging is characterized by progressive loss of cellular function and integrity. It has been thought to be driven by stochastic molecular damage. However, genetic and environmental maneuvers enhancing mitochondrial function or inhibiting glycolysis extend lifespan and promote healthy aging in many species. In post-fertile Caenorhabditis elegans, a progressive decline in phosphoenolpyruvate carboxykinase with age, and a reciprocal increase in pyruvate kinase shunt energy metabolism from oxidative metabolism to anaerobic glycolysis. This reduces the efficiency and total of energy generation. As a result, energy-dependent physical activity and other cellular functions decrease due to unmatched energy demand and supply. In return, decrease in physical activity accelerates this metabolic shift, forming a vicious cycle. This metabolic event is a determinant of aging, and is retarded by caloric restriction to counteract aging. In this review, we summarize these and other evidence supporting the idea that metabolic reprogramming is a driver of aging. We also suggest strategies to test this hypothesis
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Affiliation(s)
- Zhaoyang Feng
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Richard W Hanson
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Nathan A Berger
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Alexander Trubitsyn
- Institute of Biology and Soil Sciences of Far Eastern Brach of Russian Academy of Science, Vladivostok, Russia
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17
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Long non-coding RNAs involved in autophagy regulation. Cell Death Dis 2017; 8:e3073. [PMID: 28981093 PMCID: PMC5680586 DOI: 10.1038/cddis.2017.464] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 01/17/2023]
Abstract
Autophagy degrades non-functioning or damaged proteins and organelles to maintain cellular homeostasis in a physiological or pathological context. Autophagy can be protective or detrimental, depending on its activation status and other conditions. Therefore, autophagy has a crucial role in a myriad of pathophysiological processes. From the perspective of autophagy-related (ATG) genes, the molecular dissection of autophagy process and the regulation of its level have been largely unraveled. However, the discovery of long non-coding RNAs (lncRNAs) provides a new paradigm of gene regulation in almost all important biological processes, including autophagy. In this review, we highlight recent advances in autophagy-associated lncRNAs and their specific autophagic targets, as well as their relevance to human diseases such as cancer, cardiovascular disease, diabetes and cerebral ischemic stroke.
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18
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Yin Y, Sun G, Li E, Kiselyov K, Sun D. ER stress and impaired autophagy flux in neuronal degeneration and brain injury. Ageing Res Rev 2017; 34:3-14. [PMID: 27594375 DOI: 10.1016/j.arr.2016.08.008] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/31/2016] [Indexed: 12/12/2022]
Abstract
Autophagy is a highly controlled lysosome-mediated function in eukaryotic cells to eliminate damaged or aged long-lived proteins and organelles. It is required for restoring cellular homeostasis in cell survival under multiple stresses. Autophagy is known to be a double-edged sword because too much activation or inhibition of autophagy can disrupt homeostatic degradation of protein and organelles within the brain and play a role in neuronal cell death. Many factors affect autophagy flux function in the brain, including endoplasmic reticulum (ER) stress, oxidative stress, and aging. Newly emerged research indicates that altered autophagy flux functionality is involved in neurodegeneration of the aged brain, chronic neurological diseases, and after traumatic and ischemic brain injuries. In search to identify neuroprotective agents that may reduce oxidative stress and stimulate autophagy, one particular neuroprotective agent docosahexaenoic acid (DHA) presents unique functions in reducing ER and oxidative stress and modulating autophagy. This review will summarize the recent findings on changes of autophagy in aging, neurodegenerative diseases, and brain injury after trauma or ischemic strokes. Discussion of DHA functions is focused on modulating ER stress and autophagy in regard to its neuroprotection and anti-tumor functions.
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Affiliation(s)
- Yan Yin
- Department of Neurology, The Second Hospital of Dalian Medical University, Dalian 116023, PR China; Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, United States.
| | - George Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Eric Li
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Kirill Kiselyov
- Department of Biological Science, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, United States; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Education and Clinical Center, Pittsburgh, PA 15213, United States.
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19
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Franco R, Martínez-Pinilla E, Navarro G, Zamarbide M. Potential of GPCRs to modulate MAPK and mTOR pathways in Alzheimer's disease. Prog Neurobiol 2017; 149-150:21-38. [PMID: 28189739 DOI: 10.1016/j.pneurobio.2017.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 01/20/2017] [Accepted: 01/22/2017] [Indexed: 02/08/2023]
Abstract
Despite efforts to understand the mechanism of neuronal cell death, finding effective therapies for neurodegenerative diseases is still a challenge. Cognitive deficits are often associated with neurodegenerative diseases. Remarkably, in the absence of consensus biomarkers, diagnosis of diseases such as Alzheimer's still relies on cognitive tests. Unfortunately, all efforts to translate findings in animal models to the patients have been unsuccessful. Alzheimer's disease may be addressed from two different points of view, neuroprotection or cognitive enhancement. Based on recent data, the mammalian target of rapamycin (mTOR) pathway arises as a versatile player whose modulation may impact on mechanisms of both neuroprotection and cognition. Whereas direct targeting of mTOR does not seem to constitute a convenient approach in drug discovery, its indirect modulation by other signaling pathways seems promising. In fact, G-protein-coupled receptors (GPCRs) remain the most common 'druggable' targets and as such pharmacological manipulation of GPCRs with selective ligands may modulate phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), mitogen-activated protein (MAP) kinase and mTOR signaling pathways. Thus, GPCRs become important targets for potential drug treatments in different neurodegenerative disorders including, but not limited to, Alzheimer's disease. GPCR-mediated modulation of mTOR may take advantage of different GPCRs coupled to different G-dependent and G-independent signal transduction routes, of functional selectivity and/or of biased agonism. Signals mediated by GPCRs may act as coincidence detectors to achieve different benefits in different stages of the neurodegenerative disease.
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Affiliation(s)
- Rafael Franco
- Department of Biochemistry and Molecular Biomedicine and IBUB (Institute of Biomedicine of the University of Barcelona), University of Barcelona, Barcelona, Spain; Centro de investigación en Red: Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
| | - Eva Martínez-Pinilla
- Instituto de Neurociencias del Principado de Asturias (INEUROPA), Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias, Spain
| | - Gemma Navarro
- Department of Biochemistry and Molecular Biomedicine and IBUB (Institute of Biomedicine of the University of Barcelona), University of Barcelona, Barcelona, Spain; Centro de investigación en Red: Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
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20
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Abstract
Mitochondria constitute the main energy-producing centers of eukaryotic cells. In addition, they are involved in several crucial cellular processes, such as lipid metabolism, calcium buffering, and apoptosis. As such, their malfunction can be detrimental for proper cellular physiology and homeostasis. Mitophagy is a mechanism that protects and maintains cellular function by sequestering harmful or dysfunctional mitochondria to lysosomes for degradation. In this report, we present experimental procedures for quantitative, in vivo monitoring of mitophagy events in the nematode Caenorhabditis elegans.
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21
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Theoretical principles for biology: Organization. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:24-35. [PMID: 27521451 DOI: 10.1016/j.pbiomolbio.2016.07.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/20/2016] [Accepted: 07/29/2016] [Indexed: 01/21/2023]
Abstract
In the search of a theory of biological organisms, we propose to adopt organization as a theoretical principle. Organization constitutes an overarching hypothesis that frames the intelligibility of biological objects, by characterizing their relevant aspects. After a succinct historical survey on the understanding of organization in the organicist tradition, we offer a specific characterization in terms of closure of constraints. We then discuss some implications of the adoption of organization as a principle and, in particular, we focus on how it fosters an original approach to biological stability, as well as and its interplay with variation.
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22
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Zhou YF, Wang QX, Zhou HY, Chen G. Autophagy activation prevents sevoflurane-induced neurotoxicity in H4 human neuroglioma cells. Acta Pharmacol Sin 2016; 37:580-8. [PMID: 27041458 DOI: 10.1038/aps.2016.6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/19/2016] [Indexed: 12/13/2022] Open
Abstract
AIM The inhaled anesthetic sevoflurane may induce cognitive impairment in both animals and humans. Previous study has shown that sevoflurane triggers ER stress and may lead to apoptosis in rat hippocampal neurons. In this study, we examined whether sevoflurane caused autophagy and its contributions to sevoflurane induced neuronal cell injury. METHODS H4 human neuroglioma cells were exposed to 4.1% sevoflurane for 6 h. Cell viability and apoptosis ratio were assessed using a CCK8 kit and flow cytometry, respectively. Autophagosomes in the cells were detected using GFP-LC3 plasmid transfection or transmission electronic microscopy. The expression of LC3B, p62/SQSTM, C/EBP homologous protein (CHOP) and glucose-related protein 78 (GRP78) was assessed with Western blotting. RESULTS Sevoflurane treatment induced apoptosis and markedly increased the LC3-II level and GFP-LC3 puncta number, decreased p62 expression in H4 cells. Activation of autophagy by rapamycin (1 μmol/L) significantly reduced sevoflurane-induced apoptosis and increased cell viability, whereas inhibition of autophagy with 3-MA (5 mmol/L) caused the opposite effects. Furthermore, sevoflurane treatment markedly increased the expression of CHOP and GRP78, two hallmark proteins of ER stress. Inhibition of ER stress by 4-phenylbutyrate (500 μmol/L) abrogated sevoflurane-induced autophagy and apoptosis, and improved the viability. Moreover, sevoflurane-stimulated expression of CHOP and GRP78 was inhibited by rapamycin, but further enhanced by 3-MA. CONCLUSION Sevoflurane treatment induces ER stress and activates autophagy, which antagonizes sevoflurane-induced apoptosis in H4 human neuroglioma cells. The results suggest that autophagy may be a potential therapeutic target in preventing sevoflurane-induced neurotoxicity.
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23
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Li YS, Zhang FJ, Zeng C, Luo W, Xiao WF, Gao SG, Lei GH. Autophagy in osteoarthritis. Joint Bone Spine 2016; 83:143-8. [DOI: 10.1016/j.jbspin.2015.06.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 06/21/2015] [Indexed: 01/15/2023]
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24
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Lee MJ, Kim EH, Lee SA, Kang YM, Jung CH, Yoon HK, Seol SM, Lee YL, Lee WJ, Park JY. Dehydroepiandrosterone prevents linoleic acid-induced endothelial cell senescence by increasing autophagy. Metabolism 2015; 64:1134-45. [PMID: 26051603 DOI: 10.1016/j.metabol.2015.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 04/28/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Autophagy has emerged as a potentially important factor in the pathogenesis of atherosclerosis. Dehydroepiandrosterone (DHEA) is an adrenal steroid of great recent interest due to its anti-aging and anti-atherogenic effects; however, little is known about its role in autophagy and endothelial senescence. OBJECTIVE The aim of this study was to investigate whether DHEA prevents linoleic acid (LA)-induced endothelial senescence by enhancing autophagy. MATERIALS/METHODS After pre-treatement with or without DHEA prior to LA treatment in human aortic endothelial cells (HAECs), the level of senescence was compared by senescence-associated acidic β-galactosidase (SA-β-Gal) staining and hyperphosphorylated pRB (ppRB) protein level. Autophagy was detected by LC3 conversion and measuring the level of p62/SQSTM1 (sequestosome 1), a protein degraded by autophagy. The fusion of autophagosome and lysosome was confirmed by fluorescence microscopy. RESULTS Pre-treatment with DHEA inhibited LA-induced endothelial senescence. DHEA increased the conversion of LC3-I to LC3-II and decreased the level of p62 in a time- and dose-dependent manner. Although both DHEA and LA treatment increased the conversion of LC3-I to LC3-II, treatment of LA increased p62 and decreased fusion of autophagosome and lysosome, which reflected decreased autophagic flux. However, pre-treatment with DHEA restored autophagic flux inhibited by LA. When we evaluated signaling pathways, we found that JNK activation involved in LC3 conversion induced by DHEA. CONCLUSION DHEA prevents LA-induced endothelial senescence by restoring autophagy and autophagic flux through JNK activation.
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Affiliation(s)
- Min Jung Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Eun Hee Kim
- Department of Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang Ah Lee
- Department of Internal Medicine, Jeju National University Hospital, Jeju National School of Medicine, Jeju, Republic of Korea
| | - Yu Mi Kang
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Chang Hee Jung
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Hae Kyeong Yoon
- Asan Institute of Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - So Mi Seol
- Asan Institute of Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yoo La Lee
- Asan Institute of Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Woo Je Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
| | - Joong-Yeol Park
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
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Abstract
SIGNIFICANCE The molecular mechanism of aging is still vigorously debated, although a general consensus exists that mitochondria are significantly involved in this process. However, the previously postulated role of mitochondrial-derived reactive oxygen species (ROS) as the damaging agents inducing functional loss in aging has fallen out of favor in the recent past. In this review, we critically examine the role of ROS in aging in the light of recent advances on the relationship between mitochondrial structure and function. RECENT ADVANCES The functional mitochondrial respiratory chain is now recognized as a reflection of the dynamic association of respiratory complexes in the form of supercomplexes (SCs). Besides providing kinetic advantage (channeling), SCs control ROS generation by the respiratory chain, thus providing a means to regulate ROS levels in the cell. Depending on their concentration, these ROS are either physiological signals essential for the life of the cell or toxic species that damage cell structure and functions. CRITICAL ISSUES We propose that under physiological conditions the dynamic nature of SCs reversibly controls the generation of ROS as signals involved in mitochondrial-nuclear communication. During aging, there is a progressive loss of control of ROS generation so that their production is irreversibly enhanced, inducing a vicious circle in which signaling is altered and structural damage takes place. FUTURE DIRECTIONS A better understanding on the forces affecting SC association would allow the manipulation of ROS generation, directing these species to their physiological signaling role.
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Affiliation(s)
- Maria Luisa Genova
- Dipartimento di Scienze Biomediche e Neuromotorie, Alma Mater Studiorum-Università di Bologna , Bologna, Italy
| | - Giorgio Lenaz
- Dipartimento di Scienze Biomediche e Neuromotorie, Alma Mater Studiorum-Università di Bologna , Bologna, Italy
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Sestrin2 Protects Dopaminergic Cells against Rotenone Toxicity through AMPK-Dependent Autophagy Activation. Mol Cell Biol 2015; 35:2740-51. [PMID: 26031332 DOI: 10.1128/mcb.00285-15] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 05/22/2015] [Indexed: 12/11/2022] Open
Abstract
Dysfunction of the autophagy-lysosomal pathway (ALP) and the ubiquitin-proteasome system (UPS) was thought to be an important pathogenic mechanism in synuclein pathology and Parkinson's disease (PD). In the present study, we investigated the role of sestrin2 in autophagic degradation of α-synuclein and preservation of cell viability in a rotenone-induced cellular model of PD. We speculated that AMP-activated protein kinase (AMPK) was involved in regulation of autophagy and protection of dopaminergic cells against rotenone toxicity by sestrin2. The results showed that both the mRNA and protein levels of sestrin2 were increased in a TP53-dependent manner in Mes 23.5 cells after treatment with rotenone. Genetic knockdown of sestrin2 compromised the autophagy induction in response to rotenone, while overexpression of sestrin2 increased the basal autophagy activity. Sestrin2 presumably enhanced autophagy in an AMPK-dependent fashion, as sestrin2 overexpression activated AMPK, and genetic knockdown of AMPK abrogated autophagy induction by rotenone. Restoration of AMPK activity by metformin after sestrin2 knockdown recovered the autophagy activity. Sestrin2 overexpression ameliorated α-synuclein accumulation, inhibited caspase 3 activation, and reduced the cytotoxicity of rotenone. These results suggest that sestrin2 upregulation attempts to maintain autophagy activity and suppress rotenone cytotoxicity through activation of AMPK, and that sestrin2 exerts a protective effect on dopaminergic cells.
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27
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Bresgen N, Eckl PM. Oxidative stress and the homeodynamics of iron metabolism. Biomolecules 2015; 5:808-47. [PMID: 25970586 PMCID: PMC4496698 DOI: 10.3390/biom5020808] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/12/2022] Open
Abstract
Iron and oxygen share a delicate partnership since both are indispensable for survival, but if the partnership becomes inadequate, this may rapidly terminate life. Virtually all cell components are directly or indirectly affected by cellular iron metabolism, which represents a complex, redox-based machinery that is controlled by, and essential to, metabolic requirements. Under conditions of increased oxidative stress—i.e., enhanced formation of reactive oxygen species (ROS)—however, this machinery may turn into a potential threat, the continued requirement for iron promoting adverse reactions such as the iron/H2O2-based formation of hydroxyl radicals, which exacerbate the initial pro-oxidant condition. This review will discuss the multifaceted homeodynamics of cellular iron management under normal conditions as well as in the context of oxidative stress.
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Affiliation(s)
- Nikolaus Bresgen
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria.
| | - Peter M Eckl
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria.
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28
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Montévil M, Mossio M. Biological organisation as closure of constraints. J Theor Biol 2015; 372:179-91. [PMID: 25752259 DOI: 10.1016/j.jtbi.2015.02.029] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/23/2015] [Accepted: 02/25/2015] [Indexed: 11/18/2022]
Abstract
We propose a conceptual and formal characterisation of biological organisation as a closure of constraints. We first establish a distinction between two causal regimes at work in biological systems: processes, which refer to the whole set of changes occurring in non-equilibrium open thermodynamic conditions; and constraints, those entities which, while acting upon the processes, exhibit some form of conservation (symmetry) at the relevant time scales. We then argue that, in biological systems, constraints realise closure, i.e. mutual dependence such that they both depend on and contribute to maintaining each other. With this characterisation in hand, we discuss how organisational closure can provide an operational tool for marking the boundaries between interacting biological systems. We conclude by focusing on the original conception of the relationship between stability and variation which emerges from this framework.
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Affiliation(s)
- Maël Montévil
- IHPST - UMR 8590 13, rue du Four 75006 Paris, France.
| | - Matteo Mossio
- IHPST - UMR 8590 13, rue du Four 75006 Paris, France.
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29
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Zhang Z, Cai Z, Li K, Fang Y, An L, Hu Z, Wang S, Hang H. The Effect of Ionizing Radiation on mRNA Levels of the DNA Damage Response Genes Rad9, Rad1 and Hus1 in Various Mouse Tissues. Radiat Res 2015; 183:94-104. [DOI: 10.1667/rr13781.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Zhenya Zhang
- Department of General Surgery, the Fourth Affiliated Hospital of Hebei Medical University, Shijiazhuang, 050011 China
| | - Zeyuan Cai
- Center for Peptide and Protein Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Kaiming Li
- Department of General Surgery, the Fourth Affiliated Hospital of Hebei Medical University, Shijiazhuang, 050011 China
| | - Yu Fang
- Center for Peptide and Protein Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Lili An
- Center for Peptide and Protein Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhishang Hu
- Center for Peptide and Protein Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shihua Wang
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Haiying Hang
- Center for Peptide and Protein Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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Saez I, Vilchez D. Protein clearance mechanisms and their demise in age-related neurodegenerative diseases. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.1.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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31
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Klionsky DJ, Bergamini E. Searching for the fountain of autophagy-dependent youth. Autophagy 2014; 8:1169-74. [DOI: 10.4161/auto.20788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Ureshino RP, Rocha KK, Lopes GS, Bincoletto C, Smaili SS. Calcium signaling alterations, oxidative stress, and autophagy in aging. Antioxid Redox Signal 2014; 21:123-37. [PMID: 24512092 DOI: 10.1089/ars.2013.5777] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
SIGNIFICANCE Aging is a multi-factorial process that may be associated with several functional and structural deficits which can evolve into degenerative diseases. In this review, we present data that may depict an expanded view of molecular aging theories, beginning with the idea that reactive oxygen species (ROS) are the major effectors in this process. In addition, we have correlated the importance of autophagy as a neuroprotective mechanism and discussed a link between age-related molecules, Ca(2+) signaling, and oxidative stress. RECENT ADVANCES There is evidence suggesting that alterations in Ca(2+) homeostasis, including mitochondrial Ca(2+) overload and alterations in electron transport chain (ETC) complexes, which increase cell vulnerability, are linked to oxidative stress in aging. As much as Ca(2+) signaling is altered in aged cells, excess ROS can be produced due to an ineffective coupling of mitochondrial respiration. Damaged mitochondria might not be removed by the macroautophagic system, which is hampered in aging by lipofuscin accumulation, boosting ROS generation, damaging DNA, and, ultimately, leading to apoptosis. CRITICAL ISSUES This process can lead to altered protein expression (such as p53, Sirt1, and IGF-1) and progress to cell death. This cycle can lead to increased cell vulnerability in aging and contribute to an increased susceptibility to degenerative processes. FUTURE DIRECTIONS A better understanding of Ca(2+) signaling and molecular aging alterations is important for preventing apoptosis in age-related diseases. In addition, caloric restriction, resveratrol and autophagy modulation appear to be predominantly cytoprotective, and further studies of this process are promising in age-related disease therapeutics.
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Caldeira C, Oliveira AF, Cunha C, Vaz AR, Falcão AS, Fernandes A, Brites D. Microglia change from a reactive to an age-like phenotype with the time in culture. Front Cell Neurosci 2014; 8:152. [PMID: 24917789 PMCID: PMC4040822 DOI: 10.3389/fncel.2014.00152] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/13/2014] [Indexed: 01/25/2023] Open
Abstract
Age-related neurodegenerative diseases have been associated with chronic neuroinflammation and microglia activation. However, cumulative evidence supports that inflammation only occurs at an early stage once microglia change the endogenous characteristics with aging and switch to irresponsive/senescent and dystrophic phenotypes with disease progression. Thus, it will be important to have the means to assess the role of reactive and aged microglia when studying advanced brain neurodegeneration processes and age-associated related disorders. Yet, most studies are done with microglia from neonates since there are no adequate means to isolate degenerating microglia for experimentation. Indeed, only a few studies report microglia isolation from aged animals, using either short-term cultures or high concentrations of mitogens in the medium, which trigger microglia reactivity. The purpose of this study was to develop an experimental process to naturally age microglia after isolation from neonatal mice and to characterize the cultured cells at 2 days in vitro (DIV), 10 DIV, and 16 DIV. We found that 2 DIV (young) microglia had predominant amoeboid morphology and markers of stressed/reactive phenotype. In contrast, 16 DIV (aged) microglia evidenced ramified morphology and increased matrix metalloproteinase (MMP)-2 activation, as well as reduced MMP-9, glutamate release and nuclear factor kappa-B activation, in parallel with decreased expression of Toll-like receptor (TLR)-2 and TLR-4, capacity to migrate and phagocytose. These findings together with the reduced expression of microRNA (miR)-124, and miR-155, decreased autophagy, enhanced senescence associated beta-galactosidase activity and elevated miR-146a expression, are suggestive that 16 DIV cells mainly correspond to irresponsive/senescent microglia. Data indicate that the model represent an opportunity to understand and control microglial aging, as well as to explore strategies to recover microglia surveillance function.
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Affiliation(s)
- Cláudia Caldeira
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Centro de Investigação Interdisciplinar Egas Moniz, Egas Moniz - Cooperativa de Ensino Superior, CRL, Campus Universitário Monte de Caparica, Portugal
| | - Ana F Oliveira
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Carolina Cunha
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Ana R Vaz
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Ana S Falcão
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Adelaide Fernandes
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Dora Brites
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
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Infante A, Gago A, de Eguino GR, Calvo-Fernández T, Gómez-Vallejo V, Llop J, Schlangen K, Fullaondo A, Aransay AM, Martín A, Rodríguez CI. Prelamin A accumulation and stress conditions induce impaired Oct-1 activity and autophagy in prematurely aged human mesenchymal stem cell. Aging (Albany NY) 2014; 6:264-80. [PMID: 24753226 PMCID: PMC4032794 DOI: 10.18632/aging.100651] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/03/2014] [Indexed: 12/22/2022]
Abstract
Aging, a time-dependent functional decline of biological processes, is the primary risk factor in developing diseases such as cancer, cardiovascular or degenerative diseases. There is a real need to understand the human aging process in order to increase the length of disease-free life, also known as "health span". Accumulation of progerin and prelamin A are the hallmark of a group of premature aging diseases but have also been found during normal cellular aging strongly suggesting similar mechanisms between healthy aging and LMNA-linked progeroid syndromes. How this toxic accumulation contributes to aging (physiological or pathological) remains unclear. Since affected tissues in age-associated disorders and in pathological aging are mainly of mesenchymal origin we propose a model of human aging based on mesenchymal stem cells (hMSCs) which accumulate prelamin A. We demonstrate that prelamin A-accumulating hMSCs have a premature aging phenotype which affects their functional competence in vivo. The combination of prelamin A accumulation and stress conditions enhance the aging phenotype by dysregulating the activity of the octamer binding protein Oct-1This experimental model has been fundamental to identify a new role for Oct-1 in hMSCs aging.
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Affiliation(s)
- Arantza Infante
- Stem Cells and Cell Therapy Laboratory, BioCruces Health Research Institute, Cruces University Hospital, Barakaldo 48903, Spain
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35
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Autophagy Coupling Interplay: Can Improve Cellular Repair and Aging? Mol Neurobiol 2014; 49:1270-81. [DOI: 10.1007/s12035-013-8599-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 11/19/2013] [Indexed: 12/19/2022]
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36
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Chang J, Wang W, Zhang H, Hu Y, Wang M, Yin Z. The dual role of autophagy in chondrocyte responses in the pathogenesis of articular cartilage degeneration in osteoarthritis. Int J Mol Med 2013; 32:1311-8. [PMID: 24126970 DOI: 10.3892/ijmm.2013.1520] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/27/2013] [Indexed: 11/06/2022] Open
Abstract
The present study aimed to analyze the responses to autophagy in osteoarthritis (OA) and aging chondrocytes in order to elucidate the role of autophagy in the pathogenesis of OA. We used multiple assays to confirm that autophagic activity was downregulated in chondrocytes of aged articular cartilage. Surprisingly, we found that the expression of autophagy-related proteins was not decreased in the tissues of patients with OA. We also observed that rapamycin-induced autophagy prevented the accumulation of subdiploid cells in young chondrocytes, while it induced cell death by autophagy in OA chondrocytes. Our results demonstrate that autophagic activity decreases with aging, and may be responsible for the cytoprotective effects in young cartilage. However, we found that autophagic activity in patients with OA was higher than in the aging group, and reported autophagic cell death in OA chondrocytes. These results suggest that autophagy plays both a cytoprotective and death-promoting role in the pathogenesis of OA.
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Affiliation(s)
- Jun Chang
- Department of Orthopaedics, Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, P.R. China
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Abstract
SIGNIFICANCE Lysosomes are acidic organelles containing more than fifty hydrolases that provide for the degradation of intracellular and endocytosed materials by autophagy and heterophagy, respectively. They digest a variety of macromolecules, as well as all organelles, and their integrity is crucial. As a result of the degradation of iron-containing macromolecules (e.g., ferritin and mitochondrial components) or endocytosed erythrocytes (by macrophages), lysosomes can accumulate large amounts of iron. This iron occurs often as Fe(II) due to the acidic and reducing lysosomal environment. Fe(II) is known to catalyze Fenton reactions, yielding extremely reactive hydroxyl radicals that may jeopardize lysosomal membrane integrity during oxidative stress. This results in the release of hydrolases and redox-active iron into the cytosol with ensuing damage or cell death. Lysosomes play key roles not only in apoptosis and necrosis but also in neurodegeneration, aging, and atherosclerosis. RECENT ADVANCES The damaging effect of intralysosomal iron can be hampered by endogenous or exogenous iron chelators that enter the lysosomal compartment by membrane permeation, endocytosis, or autophagy. CRITICAL ISSUES Cellular sensitivity to oxidative stress is enhanced by lysosomal redox-active iron or by lysosomal-targeted copper chelators binding copper (from degradation of copper-containing macromolecules) in redox-active complexes. Probably due to higher copper levels, lysosomes of malignant cells may be specifically sensitized by such chelators. FUTURE DIRECTIONS By increasing lysosomal redox-active iron or exposing cells to lysosomal-targeted copper chelators, it should be possible to enhance the sensitivity of cancer cells to radiation-induced oxidative stress or treatment with cytostatics that induce such stress.
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Affiliation(s)
- Alexei Terman
- Department of Clinical Pathology and Cytology, Karolinska University Hospital in Huddinge, Stockholm, Sweden
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Coto-Montes A, Boga JA, Rosales-Corral S, Fuentes-Broto L, Tan DX, Reiter RJ. Role of melatonin in the regulation of autophagy and mitophagy: a review. Mol Cell Endocrinol 2012; 361:12-23. [PMID: 22575351 DOI: 10.1016/j.mce.2012.04.009] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/15/2012] [Indexed: 01/27/2023]
Abstract
Oxidative stress plays an essential role in triggering many cellular processes including programmed cell death. Proving a relationship between apoptosis and reactive oxygen species has been the goal of numerous studies. Accumulating data point to an essential role for oxidative stress in the activation of autophagy. The term autophagy encompasses several processes including not only survival or death mechanisms, but also pexophagy, mitophagy, ER-phagy or ribophagy, depending of which organelles are targeted for specific autophagic degradation. However, whether the outcome of autophagy is survival or death and whether the initiating conditions are starvation, pathogens or death receptors, reactive oxygen species are invariably involved. The role of antioxidants in the regulation of these processes, however, has been sparingly investigated. Among the known antioxidants, melatonin has high efficacy and, in both experimental and clinical situations, its protective actions against oxidative stress are well documented. Beneficial effects against mitochondrial dysfunction have also been described for melatonin; thus, this indoleamine seems to be linked to mitophagy. The present review focuses on data and the most recent advances related to the role of melatonin in health and disease, on autophagy activation in general, and on mitophagy in particular.
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Affiliation(s)
- Ana Coto-Montes
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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39
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Killian M. Dual role of autophagy in HIV-1 replication and pathogenesis. AIDS Res Ther 2012; 9:16. [PMID: 22606989 PMCID: PMC3514335 DOI: 10.1186/1742-6405-9-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 04/21/2012] [Indexed: 12/19/2022] Open
Abstract
Autophagy, the major mechanism for degrading long-lived intracellular proteins and organelles, is essential for eukaryotic cell homeostasis. Autophagy also defends the cell against invasion by microorganisms and has important roles in innate and adaptive immunity. Increasingly evident is that HIV-1 replication is dependent on select components of autophagy. Fittingly, HIV-1 proteins are able to modulate autophagy to maximize virus production. At the same time, HIV-1 proteins appear to disrupt autophagy in uninfected cells, thereby contributing to CD4+ cell death and HIV-1 pathogenesis. These observations allow for new approaches for the treatment and possibly the prevention of HIV-1 infection. This review focuses on the relationship between autophagy and HIV-1 infection. Discussed is how autophagy plays dual roles in HIV-1 replication and HIV-1 disease progression.
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40
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Palmitate activates autophagy in INS-1E β-cells and in isolated rat and human pancreatic islets. PLoS One 2012; 7:e36188. [PMID: 22563482 PMCID: PMC3341371 DOI: 10.1371/journal.pone.0036188] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/29/2012] [Indexed: 12/16/2022] Open
Abstract
We have investigated the in vitro effects of increased levels of glucose and free fatty acids on autophagy activation in pancreatic beta cells. INS-1E cells and isolated rat and human pancreatic islets were incubated for various times (from 2 to 24 h) at different concentrations of glucose and/or palmitic acid. Then, cell survival was evaluated and autophagy activation was explored by using various biochemical and morphological techniques. In INS-1E cells as well as in rat and human islets, 0.5 and 1.0 mM palmitate markedly increased autophagic vacuole formation, whereas high glucose was ineffective alone and caused little additional change when combined with palmitate. Furthermore, LC3-II immunofluorescence co-localized with that of cathepsin D, a lysosomal marker, showing that the autophagic flux was not hampered in PA-treated cells. These effects were maintained up to 18–24 h incubation and were associated with a significant decline of cell survival correlated with both palmitate concentration and incubation time. Ultrastructural analysis showed that autophagy activation, as evidenced by the occurrence of many autophagic vacuoles in the cytoplasm of beta cells, was associated with a diffuse and remarkable swelling of the endoplasmic reticulum. Our results indicate that among the metabolic alterations typically associated with type 2 diabetes, high free fatty acids levels could play a role in the activation of autophagy in beta cells, through a mechanism that might involve the induction of endoplasmic reticulum stress.
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41
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Role of autophagy in the progression and suppression of leukemias. Crit Rev Oncol Hematol 2012; 81:275-85. [DOI: 10.1016/j.critrevonc.2011.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 03/09/2011] [Accepted: 03/25/2011] [Indexed: 11/21/2022] Open
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Cai Z, Yan LJ, Li K, Quazi SH, Zhao B. Roles of AMP-activated protein kinase in Alzheimer's disease. Neuromolecular Med 2012; 14:1-14. [PMID: 22367557 DOI: 10.1007/s12017-012-8173-2] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 02/04/2012] [Indexed: 12/22/2022]
Abstract
AMP-activated protein kinase (AMPK), a master regulator of cellular energy homeostasis and a central player in glucose and lipid metabolism, is potentially implicated in the pathogenesis of Alzheimer's disease (AD). AMPK activity decreases in AD brain, indicating decreased mitochondrial biogenesis and function. Emerging evidence demonstrates that AMPK activation is a potential target for improving perturbed brain energy metabolism that is involved in the pathogenesis of AD. The roles of AMPK in the pathogenesis of AD include β-amyloid protein (Aβ) generation and tau phosphorylation. In particular, AMPK may regulate Aβ generation through modulating neuronal cholesterol and sphingomyelin levels and through regulating APP distribution in the lipid rafts. AMPK is activated by phosphorylation of Thr-172 by LKB1 complex in response to increase in the AMP/ATP ratio and by calmodulin-dependent protein kinase kinase-beta in response to elevated Ca(2+) levels, which contributes to regulating Aβ generation. AMPK is a physiological tau kinase and can increase the phosphorylation of tau at Ser-262. AMPK can also directly phosphorylate tau at Thr-231 and Ser-396/404. Furthermore, AMPK activation decreases mTOR signaling activity to facilitate autophagy and promotes lysosomal degradation of Aβ. However, AMPK activation has non-neuroprotective property and may lead to detrimental outcomes, including Aβ generation and tau phosphorylation. Therefore, it is still unclear whether AMPK could serve a potential therapeutic target for AD, and hence, further studies will be needed to clarify the role of AMPK in AD.
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Affiliation(s)
- Zhiyou Cai
- Department of Neurology, The Affiliated Hospital of Guangdong Medical College, District of Xiashan, Zhanjiang 524001, Guangdong, People's Republic of China
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43
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Mammalian target of rapamycin: A valid therapeutic target through the autophagy pathway for alzheimer's disease? J Neurosci Res 2012; 90:1105-18. [DOI: 10.1002/jnr.23011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 10/28/2011] [Accepted: 11/18/2011] [Indexed: 12/15/2022]
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44
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Maixner N, Kovsan J, Harman-Boehm I, Blüher M, Bashan N, Rudich A. Autophagy in adipose tissue. Obes Facts 2012; 5:710-21. [PMID: 23108431 DOI: 10.1159/000343983] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 09/05/2012] [Indexed: 01/06/2023] Open
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45
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Lenaz G. Mitochondria and reactive oxygen species. Which role in physiology and pathology? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 942:93-136. [PMID: 22399420 DOI: 10.1007/978-94-007-2869-1_5] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oxidative stress is among the major causes of toxicity due to interaction of Reactive Oxygen Species (ROS) with cellular macromolecules and structures and interference with signal transduction pathways. The mitochondrial respiratory chain, specially from Complexes I and III, is considered the main origin of ROS particularly under conditions of high membrane potential, but several other sources may be important for ROS generation, such as mitochondrial p66(Shc), monoamine oxidase, α-ketoglutarate dehydogenase, besides redox cycling of redox-active molecules. ROS are able to oxidatively modify lipids, proteins, carbohydrates and nucleic acids in mitochondria and to activate/inactivate signalling pathways by oxidative modification of redox-active factors. Cells are endowed with several defence mechanisms including repair or removal of damaged molecules, and antioxidant systems, either enzymatic or non-enzymatic. Oxidative stress is at the basis of ageing and many pathological disorders, such as ischemic diseases, neurodegenerative diseases, diabetes, and cancer, although the underlying mechanisms are not always completely understood.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica, Università di Bologna, Bologna, Italy.
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46
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Budanov AV. Stress-responsive sestrins link p53 with redox regulation and mammalian target of rapamycin signaling. Antioxid Redox Signal 2011; 15:1679-90. [PMID: 20712410 PMCID: PMC3151419 DOI: 10.1089/ars.2010.3530] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The tumor suppressor p53 protects organisms from most types of cancer through multiple mechanisms. The p53 gene encodes a stress-activated transcriptional factor that transcriptionally regulates a large set of genes with versatile functions. These p53-activated genes mitigate consequences of stress regulating cell viability, growth, proliferation, repair, and metabolism. Recently, we described a novel antioxidant function of p53, which is important for its tumor suppressor activity. Among the many antioxidant genes activated by p53, Sestrins (Sesns) are critical for suppression of reactive oxygen species (ROS) and protection from oxidative stress, transformation, and genomic instability. Sestrins can regulate ROS through their direct effect on antioxidant peroxiredoxin proteins and through the AMP-activated protein kinase-target of rapamycin signaling pathway. The AMP-activated protein kinase-target of rapamycin axis is critical for regulation of metabolism and autophagy, two processes associated with ROS production, and deregulation of this pathway increases vulnerability of the organism to stress, aging, and age-related diseases, including cancer. Recently, we have shown that inactivation of Sestrin in fly causes accumulation of age-associated damage. Hence, Sestrins can link p53 with aging and age-related diseases.
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Affiliation(s)
- Andrei V Budanov
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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47
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Kurz T, Eaton JW, Brunk UT. The role of lysosomes in iron metabolism and recycling. Int J Biochem Cell Biol 2011; 43:1686-97. [PMID: 21907822 DOI: 10.1016/j.biocel.2011.08.016] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 08/25/2011] [Accepted: 08/26/2011] [Indexed: 02/07/2023]
Abstract
Iron is the most abundant transition metal in the earth's crust. It cycles easily between ferric (oxidized; Fe(III)) and ferrous (reduced; Fe(II)) and readily forms complexes with oxygen, making this metal a central player in respiration and related redox processes. However, 'loose' iron, not within heme or iron-sulfur cluster proteins, can be destructively redox-active, causing damage to almost all cellular components, killing both cells and organisms. This may explain why iron is so carefully handled by aerobic organisms. Iron uptake from the environment is carefully limited and carried out by specialized iron transport mechanisms. One reason that iron uptake is tightly controlled is that most organisms and cells cannot efficiently excrete excess iron. When even small amounts of intracellular free iron occur, most of it is safely stored in a non-redox-active form in ferritins. Within nucleated cells, iron is constantly being recycled from aged iron-rich organelles such as mitochondria and used for construction of new organelles. Much of this recycling occurs within the lysosome, an acidic digestive organelle. Because of this, most lysosomes contain relatively large amounts of redox-active iron and are therefore unusually susceptible to oxidant-mediated destabilization or rupture. In many cell types, iron transit through the lysosomal compartment can be remarkably brisk. However, conditions adversely affecting lysosomal iron handling (or oxidant stress) can contribute to a variety of acute and chronic diseases. These considerations make normal and abnormal lysosomal handling of iron central to the understanding and, perhaps, therapy of a wide range of diseases.
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Affiliation(s)
- Tino Kurz
- Division of Pharmacology, Faculty of Health Sciences, Linköping University, 581 85 Linköping, Sweden.
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48
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Age-related autophagy alterations in the brain of senescence accelerated mouse prone 8 (SAMP8) mice. Exp Gerontol 2011; 46:533-41. [DOI: 10.1016/j.exger.2011.02.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/09/2011] [Accepted: 02/09/2011] [Indexed: 12/19/2022]
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49
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Kim I, Lemasters JJ. Mitophagy selectively degrades individual damaged mitochondria after photoirradiation. Antioxid Redox Signal 2011; 14:1919-28. [PMID: 21126216 PMCID: PMC3078512 DOI: 10.1089/ars.2010.3768] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 12/02/2010] [Indexed: 11/13/2022]
Abstract
Damaged and dysfunctional mitochondria are proposed to be removed by autophagy. However, selective degradation of damaged mitochondria by autophagy (mitophagy) has yet to be experimentally verified. In this study, we investigated the cellular fate of individual mitochondria damaged by photoirradiation in hepatocytes isolated from transgenic mice expressing green fluorescent protein fused to microtubule-associated protein 1 light chain 3, a marker of forming and newly formed autophagosomes. Photoirradiation with 488-nm light induced mitochondrial depolarization (release of tetramethylrhodamine methylester [TMRM]) in a dose-dependent fashion. At lower doses of light, mitochondria depolarized transiently with re-polarization within 3 min. With greater light, mitochondrial depolarization became irreversible. Irreversible, but not reversible, photodamage induced autophagosome formation after 32±5 min. Photodamage-induced mitophagy was independent of TMRM, as photodamage also induced mitophagy in the absence of TMRM. Photoirradiation with 543-nm light did not induce mitophagy. As revealed by uptake of LysoTracker Red, mitochondria weakly acidified after photodamage before a much stronger acidification after autophagosome formation. Photodamage-induced mitophagy was not blocked by phosphatidylinositol 3-kinase inhibition with 3-methyladenine (10 mM) or wortmannin (100 nM). In conclusion, individual damaged mitochondria become selectively degraded by mitophagy, but photodamage-induced mitophagic sequestration occurs independently of the phosphatidylinositol 3-kinase signaling pathway, the classical upstream signaling pathway of nutrient deprivation-induced autophagy.
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Affiliation(s)
- Insil Kim
- Center for Cell Death, Injury, and Regeneration, Departments of Pharmaceutical and Biomedical Sciences and Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - John J. Lemasters
- Center for Cell Death, Injury, and Regeneration, Departments of Pharmaceutical and Biomedical Sciences and Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina
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Knight WD, Witte MM, Parsons AD, Gierach M, Overton JM. Long-term caloric restriction reduces metabolic rate and heart rate under cool and thermoneutral conditions in FBNF1 rats. Mech Ageing Dev 2011; 132:220-9. [PMID: 21513729 DOI: 10.1016/j.mad.2011.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 02/14/2011] [Accepted: 04/02/2011] [Indexed: 12/21/2022]
Abstract
The long-term metabolic and cardiovascular responses to caloric restriction (CR) are poorly understood. We examined the responses to one year of CR in FBNF1 rats housed in cool (COOL; T(a)=15 °C) or thermoneutral (TMN; T(a)=30 °C) conditions. Rats were acclimated to COOL or TMN for 2 months, instrumented for cardiovascular telemetry and studied in calorimeters. Baseline caloric intake, oxygen consumption (VO(2)), mean arterial blood pressure (MAP), and heart rate (HR) were determined prior to assignment to ad lib (AL) or CR groups (30-40% CR) within each T(a) (n = 8). Groups of rats were studied after 10 weeks CR, one year CR, and after 4 days of re-feeding. Both 10 weeks and one year of CR reduced HR and VO(2) irrespective of T(a). Evaluation of the relationship between metabolic organ mass (liver, heart, brain, and kidney mass) and energy expenditure revealed a clear shift induced by CR to reduce expenditure per unit metabolic mass in both COOL and TMN groups. Re-feeding resulted in prompt elevations of HR and VO(2) to levels observed in control rats. These findings are consistent with the hypothesis that long term CR produces sustained reductions in metabolic rate and heart rate in rats.
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Affiliation(s)
- W David Knight
- Department of Biomedical Sciences and Program in Neuroscience, Florida State University, College of Medicine, Tallahassee, FL 32306-4340, USA
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