151
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Wang Y, Wang W, Li D, Li M, Wang P, Wen J, Liang M, Su B, Yin Y. IGF-1 alleviates NMDA-induced excitotoxicity in cultured hippocampal neurons against autophagy via the NR2B/PI3K-AKT-mTOR pathway. J Cell Physiol 2014; 229:1618-29. [PMID: 24604717 DOI: 10.1002/jcp.24607] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 03/05/2014] [Indexed: 12/30/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) is a brain-specific multifunctional protein involved in neuronal polarity and axonal guidance. Mature IGF-1 triggers three enzymes, mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and phosphoinositide phospholipase C-γ (PLC-γ), which are its predominant downstream regulators. The PI3K-AKT signaling pathway is upstream of the mammalian target of rapamycin (mTOR), which is of great importance in the induction of autophagy. However, whether the neuroprotective effect of IGF-1 against excitotoxicity is mediated by autophagy through the PI3K/AKT/mTOR pathway remains to be elucidated. The induction of autophagy following NMDA treatment was determined by microtubule-associated protein light chain 3 (LC3) conversion and the result of this autophagy was assessed by monitoring the cleavage of caspase 3 in cultured hippocampal neurons. Cell viability was determined using MTT and LDH assay, and PI-staining was used to estimate the fate of autophagy and the protective effect of IGF-1. In addition, IGF-1 was found to decrease autophagy induced by NMDA using transmission electron microscopy and MDC staining. The protective effect of IGF-1 against autophagy was accompanied with up-regulation of phospho-AKT (p-AKT) and phospho-mTOR (p-mTOR), which was blocked by the inhibitor of PI3K. At the same time, the activation of NR2B resulting in the down-regulation of p-AKT and p-mTOR was blocked by IGF-1. Together, these data suggest that NMDA induces the autophagy, followed by apoptosis in cultured hippocampal neurons, and that IGF-1 can block this effect via inhibition of NR2B receptors and activation of the PI3K-AKT-mTOR pathway.
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Affiliation(s)
- Yansong Wang
- Department of Neurobiology and Beijing Institute for Brain Disorders, School of Basic Medical Sciences, Capital Medical University, Beijing, P.R. China; Department of Spine Surgery, Institute of Hard Tissue Development and Regeneration of Harbin Medical University, Second Affiliated Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province, P.R. China
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152
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Corrochano S, Renna M, Osborne G, Carter S, Stewart M, May J, Bates GP, Brown SDM, Rubinsztein DC, Acevedo-Arozena A. Reducing Igf-1r levels leads to paradoxical and sexually dimorphic effects in HD mice. PLoS One 2014; 9:e105595. [PMID: 25140802 PMCID: PMC4139380 DOI: 10.1371/journal.pone.0105595] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 07/26/2014] [Indexed: 01/09/2023] Open
Abstract
Many of the neurodegenerative diseases that afflict people in later life are associated with the formation of protein aggregates. These so-called “proteinopathies” include Alzheimer’s disease (AD) and Huntington’s disease (HD). The insulin/insulin-like growth factor signalling (IIS) pathway has been proposed to modulate such diseases in model organisms, as well as the general ageing process. In this pathway, insulin-like growth factor binds to insulin-like growth factor receptors, such as the insulin-like growth factor 1 receptor (IGF-1R). Heterozygous deletion of Igf-1r has been shown to lead to increased lifespan in mice. Reducing the activity of this pathway had benefits in a HD C. elegans model, and some of these may be attributed to the expected inhibition of mTOR activity resulting in an increase in autophagy, which would enhance mutant huntingtin clearance. Thus, we tested if heterozygous deletion of Igf-1r would lead to benefits in HD related phenotypes in the mouse. Surprisingly, reducing Igf-1r levels led to some beneficial effects in HD females, but also led to some detrimental effects in HD males. Interestingly, Igf-1r deficiency had no discernible effects on downstream mTOR signalling in HD mice. These results do not support a broad beneficial effect of diminishing the IIS pathway in HD pathology in a mammalian system.
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Affiliation(s)
| | - Maurizio Renna
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Wellcome/MRC Building, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Georgina Osborne
- Department of Medical and Molecular Genetics, King's College London, London, United Kingdom
| | - Sarah Carter
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire, United Kingdom
| | - Michelle Stewart
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire, United Kingdom
| | - Joel May
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire, United Kingdom
| | - Gillian P Bates
- Department of Medical and Molecular Genetics, King's College London, London, United Kingdom
| | - Steve D M Brown
- MRC Mammalian Genetics Unit, Harwell, Oxfordshire, United Kingdom
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Wellcome/MRC Building, Addenbrooke's Hospital, Cambridge, United Kingdom
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153
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Fragkouli A, Doxakis E. miR-7 and miR-153 protect neurons against MPP(+)-induced cell death via upregulation of mTOR pathway. Front Cell Neurosci 2014; 8:182. [PMID: 25071443 PMCID: PMC4080263 DOI: 10.3389/fncel.2014.00182] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 06/13/2014] [Indexed: 12/15/2022] Open
Abstract
Differential expression of microRNAs (miRs) in the brain of patients with neurodegenerative diseases suggests that they may have key regulatory roles in the development of these disorders. Two such miRs, miR-7, and miR-153 have recently been shown to target α-synuclein, a protein critically involved in the pathological process of Parkinson's disease. By using a well-established in culture Parkinson's disease model that of neurotoxin 1-Methyl-4-Phenyl-Pyridinium (MPP+), we examined whether miR-7 and miR-153 display neuroprotective properties. Herein, we demonstrate that treatment of cortical neurons with MPP+ induced a dose-dependent cell death with apoptotic characteristics. This was reflected in altered intracellular signaling characterized by increased levels of activated kinases p38MAPK and ERK1/2 and reduced levels of activated AKT, p70S6K, and SAPK/JNK. Overexpression of miR-7 or miR-153 by adenoviral transduction protected cortical neurons from MPP+-induced toxicity, restored neuronal viability and anti-apoptotic BCL-2 protein levels while attenuated activation of caspase-3. Moreover, both miR-7 and miR-153 interfered with MPP+-induced alterations in intracellular signaling pathways in a partially overlapping manner; specifically, they preserved activation of mTOR and SAPK/JNK signaling pathways in the MPP+-treated neurons, while miR-153 also attenuated MPP+-induced activation of p38MAPK. No major effects were observed in the rest of signaling cascades or proteins investigated. Furthermore, the neuroprotective effect of miR-7 and miR-153 was alleviated when MPP+ was co-administered with rapamycin. Taken together, our results suggest that miR-7 and miR-153 protect neurons from cell death by interfering with the MPP+-induced downregulation of mTOR signaling.
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Affiliation(s)
- Apostolia Fragkouli
- Lab of Molecular and Cellular Neuroscience, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens Athens, Greece
| | - Epaminondas Doxakis
- Lab of Molecular and Cellular Neuroscience, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens Athens, Greece
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154
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Higashi Y, Quevedo HC, Tiwari S, Sukhanov S, Shai SY, Anwar A, Delafontaine P. Interaction between insulin-like growth factor-1 and atherosclerosis and vascular aging. FRONTIERS OF HORMONE RESEARCH 2014; 43:107-24. [PMID: 24943302 DOI: 10.1159/000360571] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The process of vascular aging encompasses alterations in the function of endothelial (ECs) and vascular smooth muscle cells (VSMCs) via oxidation, inflammation, cell senescence and epigenetic modifications, increasing the probability of atherosclerosis. Aged vessels exhibit decreased endothelial antithrombogenic properties, increased reactive oxygen species generation, inflammatory signaling and migration of VSMCs to the subintimal space, impaired angiogenesis and increased elastin degradation. The key initiating step in atherogenesis is subendothelial accumulation of apolipoprotein B-containing low-density lipoproteins resulting in activation of ECs and recruitment of monocytes. Activated ECs secrete 'chemokines' that interact with cognate chemokine receptors on monocytes and promote directional migration. Recruitment of immune cells establishes a proinflammatory status, further causing elevated oxidative stress, which in turn triggers a series of events including apoptotic or necrotic death of vascular and nonvascular cells. Increased oxidative stress is also considered to be a key factor in mechanisms of aging-associated changes in tissue integrity and function. Experimental evidence indicates that insulin-like growth factor-1 exerts antioxidant, anti-inflammatory and pro-survival effects on the vasculature, reducing atherosclerotic plaque burden and promoting features of atherosclerotic plaque stability.
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Affiliation(s)
- Yusuke Higashi
- Tulane University School of Medicine, Tulane University Heart and Vascular Institute, New Orleans, La., USA
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155
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Li J, Zhao L, Yang T, Zeng YJ, Yang K. c-Ski inhibits autophagy of vascular smooth muscle cells induced by oxLDL and PDGF. PLoS One 2014; 9:e98902. [PMID: 24887307 PMCID: PMC4041777 DOI: 10.1371/journal.pone.0098902] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/08/2014] [Indexed: 12/27/2022] Open
Abstract
Autophagy is increasingly being recognized as a critical determinant of vascular smooth muscle cell (VSMC) biology. Previously, we have demonstrated that c-Ski inhibits VSMC proliferation stimulated by transforming growth factor β (TGF-β), but it is not clear whether c-Ski has the similar protective role against other vascular injury factors and whether regulation of autophagy is involved in its protective effects on VSMC. Accordingly, in this study, rat aortic A10 VSMCs were treated with 40 µg/ml oxidized low-density lipoprotein (oxLDL) or 20 ng/ml platelet-derived growth factor (PDGF), both of which were autophagy inducers and closely related to the abnormal proliferation of VSMCs. Overexpression of c-Ski in A10 cells significantly suppressed the oxLDL- and PDGF- induced autophagy. This action of c-Ski resulted in inhibiting the cell proliferation, the decrease of contractile phenotype marker α-SMA expression while the increase of synthetic phenotype marker osteopontin expression stimulated by oxLDL or PDGF. Inversely, knockdown of c-Ski by RNAi enhanced the stimulatory effects of oxLDL or PDGF on A10 cell growth and phenotype transition. And further investigation found that inhibition of AKT phosphorylation to downregulate proliferating cell nuclear antigen (PCNA) expression, was involved in the regulation of autophagy and associated functions by c-Ski in the oxLDL- and PDGF-stimulated VSMCs. Collectively, c-Ski may play an important role in inhibiting autophagy to protect VSMCs against some harsh stress including oxLDL and PDGF.
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Affiliation(s)
- Jun Li
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China
- * E-mail:
| | - Li Zhao
- Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing, China
| | - Ting Yang
- Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing, China
| | - Yi-Jun Zeng
- Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing, China
| | - Kang Yang
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China
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156
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Qi GM, Jia LX, Li YL, Li HH, Du J. Adiponectin suppresses angiotensin II-induced inflammation and cardiac fibrosis through activation of macrophage autophagy. Endocrinology 2014; 155:2254-65. [PMID: 24684303 DOI: 10.1210/en.2013-2011] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Previous studies have indicated that adiponectin (APN) protects against cardiac remodeling, but the underlying mechanism remains unclear. The present study aimed to elucidate how APN regulates inflammatory responses and cardiac fibrosis in response to angiotensin II (Ang II). Male APN knockout (APN KO) mice and wild-type (WT) C57BL/6 littermates were sc infused with Ang II at 750 ng/kg per minute. Seven days after Ang II infusion, both APN KO and WT mice developed equally high blood pressure levels. However, APN KO mice developed more severe cardiac fibrosis and inflammation compared with WT mice. This finding was demonstrated by the up-regulation of collagen I, α-smooth muscle actin, IL-1β, and TNF-α and increased macrophage infiltration in APN KO mice. Moreover, there were substantially fewer microtubule-associated protein 1 light chain 3-positive autophagosomes in macrophages in the hearts of Ang II-infused APN KO mice. Additional in vitro studies also revealed that globular APN treatment induced autophagy, inhibited Ang II-induced nuclear factor-κB activity, and enhanced the expression of antiinflammatory cytokines, including IL-10, macrophage galactose N-acetyl-galactosamine specific lectin 2, found in inflammatory zone 1, and type-1 arginase in macrophages. In contrast, APN-induced autophagy and antiinflammatory cytokine expression was diminished in Atg5-knockdown macrophages or by Compound C, an inhibitor of adenosine 5'-monophosphate-activated protein kinase. Our study indicates that APN activates macrophage autophagy through the adenosine 5'-monophosphate-activated protein kinase pathway and suppresses Ang II-induced inflammatory responses, thereby reducing the extent of cardiac fibrosis.
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Affiliation(s)
- Guan-Ming Qi
- Beijing Anzhen Hospital (G.-M.Q., L.-X.J., Y.-L.L., J.D.), The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Capital Medical University, Ministry of Education, Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing 100029, China; and Department of Pathology (H.-H.L.), Capital Medical University, Beijing 100069, China
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157
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Burgos-Portugal JA, Mitchell HM, Castaño-Rodríguez N, Kaakoush NO. The role of autophagy in the intracellular survival of Campylobacter concisus. FEBS Open Bio 2014; 4:301-9. [PMID: 24918042 PMCID: PMC4048850 DOI: 10.1016/j.fob.2014.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/03/2014] [Accepted: 03/13/2014] [Indexed: 12/13/2022] Open
Abstract
Autophagy is involved in host clearance of Campylobacter concisus. C. concisus can be found within Campylobacter-containing vacuoles. Some C. concisus strains may subvert autophagy to survive intracellularly. Proteins specific to invasive C. concisus may be involved in autophagy subversion. Proteins of interest in C. concisus infection: ATG4B, ATG7, ATG9B, CTSD and LAMP1.
Campylobacter concisus is an emerging pathogen that has been associated with gastrointestinal diseases. Given the importance of autophagy for the elimination of intracellular bacteria and the subversion of this process by pathogenic bacteria, we investigated the role of autophagy in C. concisus intracellular survival. Gentamicin protection assays were employed to assess intracellular levels of C. concisus within Caco-2 cells, following autophagy induction and inhibition. To assess the interaction between C. concisus and autophagosomes, confocal microscopy, scanning electron microscopy, and transmission electron microscopy were employed. Expression levels of 84 genes involved in the autophagy process were measured using qPCR. Autophagy inhibition resulted in two- to four-fold increases in intracellular levels of C. concisus within Caco-2 cells, while autophagy induction resulted in a significant reduction in intracellular levels or bacterial clearance. C. concisus strains with low intracellular survival levels showed a dramatic increase in these levels upon autophagy inhibition. Confocal microscopy showed co-localization of the bacterium with autophagosomes, while transmission electron microscopy identified intracellular bacteria persisting within autophagic vesicles. Further, qPCR showed that following infection, 13 genes involved in the autophagy process were significantly regulated, and a further five showed borderline results, with an overall indication towards a dampening effect exerted by the bacterium on this process. Our data collectively indicates that while autophagy is important for the clearance of C. concisus, some strains may manipulate this process to benefit their intracellular survival.
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Affiliation(s)
- Jose A Burgos-Portugal
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Hazel M Mitchell
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Natalia Castaño-Rodríguez
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Nadeem O Kaakoush
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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158
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Selective inhibition of PI3K/Akt/mTOR signaling pathway regulates autophagy of macrophage and vulnerability of atherosclerotic plaque. PLoS One 2014; 9:e90563. [PMID: 24599185 PMCID: PMC3944201 DOI: 10.1371/journal.pone.0090563] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 01/31/2014] [Indexed: 12/21/2022] Open
Abstract
Macrophage infiltration contributes to the instability of atherosclerotic plaques. In the present study, we investigated whether selective inhibition of PI3K/Akt/mTOR signaling pathway can enhance the stability of atherosclerotic plaques by activation of macrophage autophagy. In vitro study, selective inhibitors or siRNA of PI3K/Akt/mTOR pathways were used to treat the rabbit's peritoneal primary macrophage cells. Inflammation related cytokines secreted by macrophages were measured. Ultrastructure changes of macrophages were examined by transmission electron microscope. mRNA or protein expression levels of autophagy related gene Beclin 1, protein 1 light chain 3 II dots (LC3-II) or Atg5-Atg12 conjugation were assayed by quantitative RT-PCR or Western blot. In vivo study, vulnerable plaque models were established in 40 New Zealand White rabbits and then drugs or siRNA were given for 8 weeks to inhibit the PI3K/Akt/mTOR signaling pathway. Intravascular ultrasound (IVUS) was performed to observe the plaque imaging. The ultrastructure of the abdominal aortic atherosclerosis lesions were analyzed with histopathology. RT-PCR or Western blot methods were used to measure the expression levels of corresponding autophagy related molecules. We found that macrophage autophagy was induced in the presence of Akt inhibitor, mTOR inhibitor and mTOR-siRNA in vitro study, while PI3K inhibitor had the opposite role. In vivo study, we found that macrophage autophagy increased significantly and the rabbits had lower plaque rupture incidence, lower plaque burden and decreased vulnerability index in the inhibitors or siRNA treated groups. We made a conclusion that selective inhibition of the Akt/mTOR signal pathway can reduce macrophages and stabilize the vulnerable atherosclerotic plaques by promoting macrophage autophagy.
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159
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Troncoso R, Ibarra C, Vicencio JM, Jaimovich E, Lavandero S. New insights into IGF-1 signaling in the heart. Trends Endocrinol Metab 2014; 25:128-37. [PMID: 24380833 DOI: 10.1016/j.tem.2013.12.002] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/16/2013] [Accepted: 12/02/2013] [Indexed: 01/15/2023]
Abstract
Insulin-like growth factor 1 (IGF-1) signaling regulates contractility, metabolism, hypertrophy, autophagy, senescence, and apoptosis in the heart. IGF-1 deficiency is associated with an increased risk of cardiovascular disease, whereas cardiac activation of IGF-1 receptor (IGF-1R) protects from the detrimental effects of a high-fat diet and myocardial infarction. IGF-1R activates multiple pathways through its intrinsic tyrosine kinase activity and through coupling to heterotrimeric G protein. These pathways involve classic second messengers, phosphorylation cascades, lipid signaling, Ca(2+) transients, and gene expression. In addition, IGF-1R triggers signaling in different subcellular locations including the plasma membrane, perinuclear T tubules, and also in internalized vesicles. In this review, we provide a fresh and updated view of the complex IGF-1 scenario in the heart, including a critical focus on therapeutic strategies.
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Affiliation(s)
- Rodrigo Troncoso
- Facultad de Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago 838049, Chile; Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 838049, Chile
| | - Cristián Ibarra
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | | | - Enrique Jaimovich
- Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 838049, Chile
| | - Sergio Lavandero
- Facultad de Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago 838049, Chile; Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 838049, Chile; Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, Dallas, TX, 75390-8573, USA.
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160
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Russell FD, Hamilton KD. Nutrient deprivation increases vulnerability of endothelial cells to proinflammatory insults. Free Radic Biol Med 2014; 67:408-15. [PMID: 24334251 DOI: 10.1016/j.freeradbiomed.2013.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 12/05/2013] [Accepted: 12/06/2013] [Indexed: 11/21/2022]
Abstract
Nutrient deprivation is a stimulus for oxidative stress and is an established method for induction of cell autophagy and apoptosis. The aims of this study were to identify conditions that evoke superoxide production in cultured human umbilical vein endothelial cells (HUVECs), determine the mechanism of action for this response, and examine whether the stimulus might facilitate the adhesion of human isolated neutrophils to the HUVECs. HUVECs were incubated in M199 medium under conditions of serum starvation (serum-free M199 medium), low serum (medium containing 2% fetal calf serum), and high serum (medium containing 20% fetal calf serum). HUVECs were also incubated under proinflammatory conditions, in medium supplemented with 50ng/ml tumor necrosis factor-α (TNF-α) or neutrophils preactivated with 10nM phorbol 12-myristate 13-acetate (PMA). Superoxide production was increased fourfold in serum-starved HUVECs compared to cells incubated in 20% medium, and this was reduced by inhibitors of the mitochondrial electron transport chain and mitochondrial Ca(2+) uniporter. Superoxide production was 23.6% higher in HUVECs incubated with TNF-α in 2% medium compared to 2% medium alone, but unchanged with TNF-α in 20% medium. PMA-activated neutrophils adhered to morphologically aberrant HUVECs, which were mainly evident under the low-serum condition. The findings show a role of mitochondrial enzymes in superoxide production in response to nutrient deprivation and suggest that proinflammatory responses in HUVECs become manifest when HUVECs are in an already-compromised state.
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Affiliation(s)
- Fraser D Russell
- Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia.
| | - Karina D Hamilton
- Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia
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161
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Autophagy contributes to IL-17-induced plasma cell differentiation in experimental autoimmune myocarditis. Int Immunopharmacol 2014; 18:98-105. [DOI: 10.1016/j.intimp.2013.11.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/07/2013] [Accepted: 11/07/2013] [Indexed: 11/16/2022]
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162
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Choi J, Jo M, Lee E, Choi D. AKT is involved in granulosa cell autophagy regulation via mTOR signaling during rat follicular development and atresia. Reproduction 2014; 147:73-80. [DOI: 10.1530/rep-13-0386] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this study, we examined whether granulosa cell autophagy during follicular development and atresia was regulated by the class I phosphoinositide-3 kinase/protein kinase B (AKT) pathway, which is known to control the activity of mammalian target of rapamycin (mTOR), a major negative regulator of autophagy. Ovaries and granulosa cells were obtained using an established gonadotropin-primed immature rat model that induces follicular development and atresia. Autophagy was evaluated by measuring the expression level of microtubule-associated protein light chain 3-II (LC3-II) using western blots and immunohistochemistry. The activity of AKT and mTOR was also examined by observing the phosphorylation of AKT and ribosomal protein S6 kinase (S6K) respectively. After gonadotropin injection, LC3-II expression was suppressed and phosphorylation of AKT and S6K increased in rat granulosa cells. By contrast, gonadotropin withdrawal by metabolic clearance promoted LC3-II expression and decreased phosphorylation of AKT and S6K. In addition,in-vitroFSH treatment of rat granulosa cells also indicated inhibition of LC3-II expression accompanied by a marked increase in phosphorylation of AKT and S6K. Inhibition of AKT phosphorylation using AKT inhibitor VIII suppressed FSH-mediated phosphorylation of S6K, followed by an increase in LC3-II expression. Furthermore, co-treatment with FSH and AKT inhibitor increased the levels of apoptosis and cell death of granulosa cells compared with the single treatment with FSH. Taken together, our findings indicated that AKT-mediated activation of mTOR suppresses granulosa cell autophagy during follicular development and is involved in the regulation of apoptotic cell death.
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163
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Dong Y, Yin S, Jiang C, Luo X, Guo X, Zhao C, Fan L, Meng Y, Lu J, Song X, Zhang X, Chen N, Hu H. Involvement of autophagy induction in penta-1,2,3,4,6-O-galloyl-β-D-glucose-induced senescence-like growth arrest in human cancer cells. Autophagy 2013; 10:296-310. [PMID: 24389959 DOI: 10.4161/auto.27210] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Growing evidence has demonstrated that autophagy plays important and paradoxical roles in carcinogenesis, while senescence is considered to be a crucial tumor-suppressor mechanism in cancer prevention and treatment. In the present study we demonstrated that both autophagy and senescence were induced in response to penta-1,2,3,4,6-O-galloyl-β-D-glucose (PGG), a chemopreventive polyphonolic compound, in multiple types of cancer cells. Analysis of these 2 events over the experimental time course indicated that autophagy and senescence occurred in parallel early in the process and dissociated later. The long-term culture study suggested that a subpopulation of senescent cells may have the capacity to reenter the cell cycle. Inhibition of autophagy by either a chemical inhibitor or RNA interference led to a significant reduction of PGG-induced senescence, followed by induction of apoptosis. These results suggested that autophagy promoted senescence induction by PGG and that PGG might exert its anticancer activity through autophagy-mediated senescence. For the first time, these findings uncovered the relationships among autophagy, senescence, and apoptosis induced by PGG. In addition, we identified that unfolded protein response signaling played a pivotal role in the autophagy-mediated senescence phenotype. Furthermore, our data showed that activation of MAPK8/9/10 (mitogen-activated protein kinase 8/9/10/c-Jun N-terminal kinases) was an essential upstream signal for PGG-induced autophagy. Finally, the key in vitro results were validated in vivo in a xenograft mouse model of human HepG2 liver cancer. Our findings provided novel insights into understanding the mechanisms and functions of PGG-induced autophagy and senescence in human cancer cells.
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Affiliation(s)
- Yinhui Dong
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China; Department of Biomedical Sciences; Texas Tech University School of Pharmacy; Amarillo, TX USA
| | - Shutao Yin
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
| | - Cheng Jiang
- Department of Biomedical Sciences; Texas Tech University School of Pharmacy; Amarillo, TX USA
| | - Xiaohe Luo
- Department of Hepatobiliary Surgery; The First Affiliated Hospital; Harbin Medical University; Harbin, Heilongjiang China
| | - Xiao Guo
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
| | - Chong Zhao
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
| | - Lihong Fan
- College of Veterinary Medicine; China Agricultural University; Beijing, China
| | - Yubing Meng
- Nanyang Administration of Traditional Chinese Medicine; Nanyang, Henan China
| | - Junxuan Lu
- Department of Biomedical Sciences; Texas Tech University School of Pharmacy; Amarillo, TX USA
| | - Xinhua Song
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
| | - Xudong Zhang
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
| | - Ni Chen
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
| | - Hongbo Hu
- Department of Nutrition and Health; College of Food Science and Nutritional Engineering; Beijing Key Laboratory of Functional Food from Plant Resources; China Agricultural University; Beijing, China
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164
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Füllgrabe J, Klionsky DJ, Joseph B. The return of the nucleus: transcriptional and epigenetic control of autophagy. Nat Rev Mol Cell Biol 2013; 15:65-74. [PMID: 24326622 DOI: 10.1038/nrm3716] [Citation(s) in RCA: 358] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autophagy is a conserved process by which cytoplasmic components are degraded by the lysosome. It is commonly seen as a cytoplasmic event and, until now, nuclear events were not considered of primary importance for this process. However, recent studies have unveiled a transcriptional and epigenetic network that regulates autophagy. The identification of tightly controlled transcription factors (such as TFEB and ZKSCAN3), microRNAs and histone marks (especially acetylated Lys16 of histone 4 (H4K16ac) and dimethylated H3K9 (H3K9me2)) associated with the autophagic process offers an attractive conceptual framework to understand the short-term transcriptional response and potential long-term responses to autophagy.
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Affiliation(s)
- Jens Füllgrabe
- Department of Oncology Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Stockholm 17176, Sweden
| | - Daniel J Klionsky
- Life Sciences Institute and Departments of Molecular, Cellular and Developmental Biology and Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bertrand Joseph
- Department of Oncology Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Stockholm 17176, Sweden
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165
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Salabei JK, Hill BG. Implications of autophagy for vascular smooth muscle cell function and plasticity. Free Radic Biol Med 2013; 65:693-703. [PMID: 23938401 PMCID: PMC3859773 DOI: 10.1016/j.freeradbiomed.2013.08.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/02/2013] [Accepted: 08/04/2013] [Indexed: 12/14/2022]
Abstract
Vascular smooth muscle cells (VSMCs) are fundamental in regulating blood pressure and distributing oxygen and nutrients to peripheral tissues. They also possess remarkable plasticity, with the capacity to switch to synthetic, macrophage-like, or osteochondrogenic phenotypes when cued by external stimuli. In arterial diseases such as atherosclerosis and restenosis, this plasticity seems to be critical and, depending on the disease context, can be deleterious or beneficial. Therefore, understanding the mechanisms regulating VSMC phenotype and survival is essential for developing new therapies for vascular disease as well as understanding how secondary complications due to surgical interventions develop. In this regard, the cellular process of autophagy is increasingly being recognized as a major player in vascular biology and a critical determinant of VSMC phenotype and survival. Although autophagy was identified in lesional VSMCs in the 1960s, our understanding of the implications of autophagy in arterial diseases and the stimuli promoting its activation in VSMCs is only now being elucidated. In this review, we highlight the evidence for autophagy occurring in VSMCs in vivo, elaborate on the stimuli and processes regulating autophagy, and discuss the current understanding of the role of autophagy in vascular disease.
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Affiliation(s)
- Joshua K Salabei
- Diabetes and Obesity Center, Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Bradford G Hill
- Diabetes and Obesity Center, Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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166
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Renna M, Bento CF, Fleming A, Menzies FM, Siddiqi FH, Ravikumar B, Puri C, Garcia-Arencibia M, Sadiq O, Corrochano S, Carter S, Brown SD, Acevedo-Arozena A, Rubinsztein DC. IGF-1 receptor antagonism inhibits autophagy. Hum Mol Genet 2013; 22:4528-44. [PMID: 23804751 PMCID: PMC3889807 DOI: 10.1093/hmg/ddt300] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 06/20/2013] [Indexed: 12/18/2022] Open
Abstract
Inhibition of the insulin/insulin-like growth factor signalling pathway increases lifespan and protects against neurodegeneration in model organisms, and has been considered as a potential therapeutic target. This pathway is upstream of mTORC1, a negative regulator of autophagy. Thus, we expected autophagy to be activated by insulin-like growth factor-1 (IGF-1) inhibition, which could account for many of its beneficial effects. Paradoxically, we found that IGF-1 inhibition attenuates autophagosome formation. The reduced amount of autophagosomes present in IGF-1R depleted cells can be, at least in part, explained by a reduced formation of autophagosomal precursors at the plasma membrane. In particular, IGF-1R depletion inhibits mTORC2, which, in turn, reduces the activity of protein kinase C (PKCα/β). This perturbs the actin cytoskeleton dynamics and decreases the rate of clathrin-dependent endocytosis, which impacts autophagosome precursor formation. Finally, with important implications for human diseases, we demonstrate that pharmacological inhibition of the IGF-1R signalling cascade reduces autophagy also in zebrafish and mice models. The novel link we describe here has important consequences for the interpretation of genetic experiments in mammalian systems and for evaluating the potential of targeting the IGF-1R receptor or modulating its signalling through the downstream pathway for therapeutic purposes under clinically relevant conditions, such as neurodegenerative diseases, where autophagy stimulation is considered beneficial.
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Affiliation(s)
- Maurizio Renna
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Carla F. Bento
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Angeleen Fleming
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
- Department of Physiology, Development and
Neuroscience, University of Cambridge,
Cambridge, UK
| | - Fiona M. Menzies
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Farah H. Siddiqi
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Brinda Ravikumar
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Claudia Puri
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Moises Garcia-Arencibia
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | - Oana Sadiq
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
| | | | - Sarah Carter
- Mammalian Genetics Unit,
Medical Research Council, Harwell,
UK
| | | | | | - David C. Rubinsztein
- Department of Medical Genetics,
Cambridge Institute for Medical Research,
University of Cambridge, Wellcome/MRC Building,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY,
UK
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167
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Wu D, Cederbaum AI. Inhibition of autophagy promotes CYP2E1-dependent toxicity in HepG2 cells via elevated oxidative stress, mitochondria dysfunction and activation of p38 and JNK MAPK. Redox Biol 2013; 1:552-65. [PMID: 24273738 PMCID: PMC3836279 DOI: 10.1016/j.redox.2013.10.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 10/27/2013] [Indexed: 02/07/2023] Open
Abstract
Autophagy has been shown to be protective against drug and alcohol-induced liver injury. CYP2E1 plays a role in the toxicity of ethanol, carcinogens and certain drugs. Inhibition of autophagy increased ethanol-toxicity and accumulation of fat in wild type and CYP2E1 knockin mice but not in CYP2E1 knockout mice as well as in HepG2 cells expressing CYP2E1 (E47 cells) but not HepG2 cells lacking CYP2E1 (C34 cells). The goal of the current study was to evaluate whether modulation of autophagy can affect CYP2E1-dependent cytotoxicity in the E47 cells. The agents used to promote CYP2E1 -dependent toxicity were a polyunsaturated fatty acid, arachidonic acid (AA), buthionine sulfoximine (BSO), which depletes GSH, and CCl4, which is metabolized to the CCl3 radical. These three agents produced a decrease in E47 cell viability which was enhanced upon inhibition of autophagy by 3-methyladenine (3-MA) or Atg 7 siRNA. Toxicity was lowered by rapamycin which increased autophagy and was much lower to the C34 cells which do not express CYP2E1. Toxicity was mainly necrotic and was associated with an increase in reactive oxygen production and oxidative stress; 3-MA increased while rapamycin blunted the oxidative stress. The enhanced toxicity and ROS formation produced when autophagy was inhibited was prevented by the antioxidant N-Acetyl cysteine. AA, BSO and CCl4 produced mitochondrial dysfunction, lowered cellular ATP levels and elevated mitochondrial production of ROS. This mitochondrial dysfunction was enhanced by inhibition of autophagy with 3-MA but decreased when autophagy was increased by rapamycin. The mitogen activated protein kinases p38 MAPK and JNK were activated by AA especially when autophagy was inhibited and chemical inhibitors of p38 MAPK and JNK lowered the elevated toxicity of AA produced by 3-MA. These results show that autophagy was protective against the toxicity produced by several agents known to be activated by CYP2E1. Since CYP2E1 plays an important role in the toxicity of ethanol, drugs and carcinogens and is activated under various pathophysiological conditions such as diabetes, NASH and obesity, attempts to stimulate autophagy may be beneficial in preventing/lowering CYP2E1/ethanol liver injury.
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Key Words
- 3-MA, 3-methyadenine
- AA, arachidonic acid
- Autophagy
- BSO, L-buthionine sulfoximine
- C34 cells, HepG2 cells which do not express CYP2E1
- CCl4, carbon tetrachloride
- CYP2E1
- CYP2E1, cytochrome P4502E1, E47 cells, HepG2 cells which express CYP2E1
- Cox IV, cytochrome oxidase subunit 4
- Cytotoxicity
- DCFDA, 2′-7′-dichlorofluorescin-diacetate
- GSH, reduced glutathione
- JNK
- MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide
- Mitochondria dysfunction
- NAC, N-acetyl-cysteine
- P38 MAPK
- ROS
- ROS, reactive oxygen species
- Rap, rapamycin
- SOD, superoxide dismutase
- TBARs, thiobarbituric acid-reactive substances
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Affiliation(s)
| | - Arthur I. Cederbaum
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, Box 1603, One Gustave L. Levy Place, New York, NY 10029, USA
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168
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Li TY, Lin SY, Lin SC. Mechanism and Physiological Significance of Growth Factor-Related Autophagy. Physiology (Bethesda) 2013; 28:423-31. [DOI: 10.1152/physiol.00023.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Growth factors, typically defined as natural substances capable of stimulating cell growth and differentiation, are vital regulators for the survival of metazoan cells. In this review, we will focus on growth factor signaling pathways that are closely related to autophagy induction and discuss the critical roles of this fascinating cellular process in intracellular energy homeostasis, cell fate determination, and pathophysiological regulation.
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Affiliation(s)
- Terytty Yang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
| | - Shu-Yong Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
| | - Sheng-Cai Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
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169
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Gianchecchi E, Delfino DV, Fierabracci A. Recent insights on the putative role of autophagy in autoimmune diseases. Autoimmun Rev 2013; 13:231-41. [PMID: 24184881 DOI: 10.1016/j.autrev.2013.10.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 10/15/2013] [Indexed: 12/17/2022]
Abstract
The incidence of autoimmune pathologies is increasing worldwide. This has stimulated interest on their etiopathogenesis, caused by a complex interaction of genetic and environmental factors. With the advent of genome-wide linkage, candidate gene and genome wide association studies, risk polymorphisms in autophagy-related genes were discovered in several autoimmune conditions suggesting the possible contribution of autophagy to their etiopathogenesis. Autophagy represents the principal catabolic process mediated by lysosomes used by eukaryotic cells and is strictly regulated by proteins belonging to the Atg family. The function of autophagy has been well characterized in various tissues and systems, but its role in the regulation of innate and adaptive immune systems has been only recently discovered. It plays a fundamental role in the modulation of thymocyte selection and in the generation of T lymphocyte repertoire by participating in the intracellular antigen presentation on MHC class-II molecules by thymic epithelial cells. Furthermore, the generation of mice with knockout for specific autophagy-related genes induced several immunological alterations, including defects in B and T cell compartments and in T cell activation. In this review we report recent evidence on the role of autophagy in autoimmunity and discuss its relevance to the pathogenesis of these diseases. We finally highlight that future research may disclose potential new therapeutic targets for the treatment of this category of disorders by modulating the autophagic pathway.
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Affiliation(s)
- Elena Gianchecchi
- Autoimmunity Laboratory, Immunology Area, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Domenico Vittorio Delfino
- Section of Pharmacology, Toxicology and Chemotherapy, Department of Clinical and Experimental Medicine, Perugia University, Perugia, Italy
| | - Alessandra Fierabracci
- Autoimmunity Laboratory, Immunology Area, Bambino Gesù Children's Hospital IRCCS, Rome, Italy.
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170
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Nakamura T, Otsuka S, Ichii O, Sakata Y, Nagasaki KI, Hashimoto Y, Kon Y. Relationship between numerous mast cells and early follicular development in neonatal MRL/MpJ mouse ovaries. PLoS One 2013; 8:e77246. [PMID: 24124609 PMCID: PMC3790711 DOI: 10.1371/journal.pone.0077246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/09/2013] [Indexed: 11/21/2022] Open
Abstract
In the neonatal mouse ovary, clusters of oocytes called nests break into smaller cysts and subsequently form individual follicles. During this period, we found numerous mast cells in the ovary of MRL/MpJ mice and investigated their appearance and morphology with follicular development. The ovarian mast cells, which were already present at postnatal day 0, tended to localize adjacent to the surface epithelium. Among 11 different mouse strains, MRL/MpJ mice possessed the greatest number of ovarian mast cells. Ovarian mast cells were also found in DBA/1, BALB/c, NZW, and DBA/2 mice but rarely in C57BL/6, NZB, AKR, C3H/He, CBA, and ICR mice. The ovarian mast cells expressed connective tissue mast cell markers, although mast cells around the surface epithelium also expressed a mucosal mast cell marker in MRL/MpJ mice. Some ovarian mast cells migrated into the oocyte nests and directly contacted the compressed and degenerated oocytes. In MRL/MpJ mice, the number of oocytes in the nest was significantly lower than in the other strains, and the number of oocytes showed a positive correlation with the number of ovarian mast cells. The gene expression of a mast cell marker also correlated with the expression of an oocyte nest marker, suggesting a link between the appearance of ovarian ? 4mast cells and early follicular development. Furthermore, the expression of follicle developmental markers was significantly higher in MRL/MpJ mice than in C57BL/6 mice. These results indicate that the appearance of ovarian mast cells is a unique phenotype of neonatal MRL/MpJ mice, and that ovarian mast cells participate in early follicular development, especially nest breakdown.
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Affiliation(s)
- Teppei Nakamura
- Laboratory of Anatomy, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- Section of Biological Safety Research, Chitose Laboratory, Japan Food Research Laboratories, Chitose, Japan
| | - Saori Otsuka
- Laboratory of Anatomy, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Osamu Ichii
- Laboratory of Anatomy, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yuko Sakata
- Section of Biological Safety Research, Chitose Laboratory, Japan Food Research Laboratories, Chitose, Japan
| | - Ken-Ichi Nagasaki
- Section of Biological Safety Research, Chitose Laboratory, Japan Food Research Laboratories, Chitose, Japan
| | - Yoshiharu Hashimoto
- Office for Faculty Development and Teaching Enriched Veterinary Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuhiro Kon
- Laboratory of Anatomy, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- * E-mail:
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171
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Calyxin Y induces hydrogen peroxide-dependent autophagy and apoptosis via JNK activation in human non-small cell lung cancer NCI-H460 cells. Cancer Lett 2013; 340:51-62. [DOI: 10.1016/j.canlet.2013.06.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 06/16/2013] [Accepted: 06/20/2013] [Indexed: 01/21/2023]
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172
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Hernández-Breijo B, Monserrat J, Román ID, González-Rodríguez Á, Fernández-Moreno MD, Lobo MVT, Valverde ÁM, Gisbert JP, Guijarro LG. Azathioprine desensitizes liver cancer cells to insulin-like growth factor 1 and causes apoptosis when it is combined with bafilomycin A1. Toxicol Appl Pharmacol 2013; 272:568-78. [PMID: 23958494 DOI: 10.1016/j.taap.2013.07.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/23/2013] [Accepted: 07/29/2013] [Indexed: 11/18/2022]
Abstract
Hepatoblastoma is a primary liver cancer that affects children, due to the sensitivity of this tumor to insulin-like growth factor 1 (IGF-1). In this paper we show that azathioprine (AZA) is capable of inhibiting IGF1-mediated signaling cascade in HepG2 cells. The efficiency of AZA on inhibition of proliferation differs in the evaluated cell lines as follows: HepG2 (an experimental model of hepatoblastoma)>Hep3B (derived from a hepatocellular carcinoma)>HuH6 (derived from a hepatoblastoma)>>HuH7 (derived from a hepatocellular carcinoma)=Chang Liver cells (a non-malignant cellular model). The effect of AZA in HepG2 cells has been proven to derive from activation of Ras/ERK/TSC2, leading to activation of mTOR/p70S6K in a sustained manner. p70S6K phosphorylates IRS-1 in serine 307 which leads to the uncoupling between IRS-1 and p85 (the regulatory subunit of PI3K) and therefore causing the lack of response of HepG2 to IGF-1. As a consequence, proliferation induced by IGF-1 is inhibited by AZA and autophagy increases leading to senescence of HepG2 cells. Our results suggest that AZA induces the autophagic process in HepG2 activating senescence, and driving to deceleration of cell cycle but not to apoptosis. However, when simultaneous to AZA treatment the autophagy was inhibited by bafilomycin A1 and the degradation of regulatory proteins of cell cycle (e.g. Rb, E2F, and cyclin D1) provoked apoptosis. In conclusion, AZA induces resistance in hepatoblastoma cells to IGF-1, which leads to autophagy activation, and causes apoptosis when it is combined with bafilomycin A1. We are presenting here a novel mechanism of action of azathioprine, which could be useful in treatment of IGF-1 dependent tumors, especially in its combination with other drugs.
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Affiliation(s)
- Borja Hernández-Breijo
- Departamento de Biología de Sistemas, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Universidad de Alcalá, 28871 Alcalá de Henares, Spain
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173
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Nys K, Agostinis P, Vermeire S. Autophagy: a new target or an old strategy for the treatment of Crohn's disease? Nat Rev Gastroenterol Hepatol 2013; 10:395-401. [PMID: 23591407 DOI: 10.1038/nrgastro.2013.66] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the past 5 years much progress has been made in understanding the molecular basis of Crohn's disease, a multifactorial chronic inflammatory disease of the gastrointestinal tract. Data suggest that hampered autophagy--the major lysosomal pathway for recycling of cytoplasmic material--might contribute to an increased susceptibility to Crohn's disease. Consequently, intense investigations have started to evaluate the potential value of autophagy as a therapeutic target and as a highly needed diagnostic tool. Interestingly, as well as the promising introduction of direct autophagic modulators, several drugs already used in the treatment of Crohn's disease might exert at least part of their effect through the regulation of autophagy. However, whether this phenomenon contributes to or rather counteracts their therapeutic use, remains to be determined and might prove to be highly compound-specific. Here we review the complex and emerging role of autophagy modulation in the battle against Crohn's disease. Moreover, we discuss the potential benefits and deleterious effects of autophagic regulation by both new and clinically used drugs.
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Affiliation(s)
- Kris Nys
- Translational Research in Gastrointestinal Disorders, Department of Clinical and Experimental Medicine, Faculty of Medicine, Catholic University of Leuven, Herestraat 49, Box 701, 3000 Leuven, Belgium
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174
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Li PL, Zhang Y, Abais JM, Ritter JK, Zhang F. Cyclic ADP-Ribose and NAADP in Vascular Regulation and Diseases. ACTA ACUST UNITED AC 2013; 2:63-85. [PMID: 24749015 DOI: 10.1166/msr.2013.1022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP), two intracellular Ca2+ mobilizing second messengers, have been recognized as a fundamental signaling mechanism regulating a variety of cell or organ functions in different biological systems. Here we reviewed the literature regarding these ADP-ribosylcyclase products in vascular cells with a major focus on their production, physiological roles, and related underlying mechanisms mediating their actions. In particular, several hot topics in this area of research are comprehensively discussed, which may help understand some of the controversial evidence provided by different studies. For example, some new models are emerging for the agonist receptor coupling of CD38 or ADP-ribosylcyclase and for the formation of an acidic microenvironment to facilitate the production of NAADP in vascular cells. We also summarized the evidence regarding the NAADP-mediated two-phase Ca2+ release with a slow Ca2+-induced Ca2+ release (CICR) and corresponding physiological relevance. The possibility of a permanent structural space between lysosomes and sarcoplasmic reticulum (SR), as well as the critical role of lysosome trafficking in phase 2 Ca2+ release in response to some agonists are also explored. With respect to the molecular targets of NAADP within cells, several possible candidates including SR ryanodine receptors (RyRs), lysosomal transient receptor potential-mucolipin 1 (TRP-ML1) and two pore channels (TPCs) are presented with supporting and opposing evidence. Finally, the possible role of NAADP-mediated regulation of lysosome function in autophagy and atherogenesis is discussed, which may indicate a new direction for further studies on the pathological roles of cADPR and NAADP in the vascular system.
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Affiliation(s)
- Pin-Lan Li
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Yang Zhang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Justine M Abais
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Joseph K Ritter
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Fan Zhang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
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175
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Regulation of autophagy by stress-responsive transcription factors. Semin Cancer Biol 2013; 23:310-22. [PMID: 23726895 DOI: 10.1016/j.semcancer.2013.05.008] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/08/2013] [Accepted: 05/21/2013] [Indexed: 12/28/2022]
Abstract
Autophagy is an evolutionarily conserved process that promotes the lysosomal degradation of intracellular components including organelles and portions of the cytoplasm. Besides operating as a quality control mechanism in steady-state conditions, autophagy is upregulated in response to a variety of homeostatic perturbations. In this setting, autophagy mediates prominent cytoprotective effects as it sustains energetic homeostasis and contributes to the removal of cytotoxic stimuli, thus orchestrating a cell-wide, multipronged adaptive response to stress. In line with the critical role of autophagy in health and disease, defects in the autophagic machinery as well as in autophagy-regulatory signaling pathways have been associated with multiple human pathologies, including neurodegenerative disorders, autoimmune conditions and cancer. Accumulating evidence indicates that the autophagic response to stress may proceed in two phases. Thus, a rapid increase in the autophagic flux, which occurs within minutes or hours of exposure to stressful conditions and is entirely mediated by post-translational protein modifications, is generally followed by a delayed and protracted autophagic response that relies on the activation of specific transcriptional programs. Stress-responsive transcription factors including p53, NF-κB and STAT3 have recently been shown to play a major role in the regulation of both these phases of the autophagic response. Here, we will discuss the molecular mechanisms whereby autophagy is orchestrated by stress-responsive transcription factors.
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176
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Troncoso R, Díaz-Elizondo J, Espinoza SP, Navarro-Marquez MF, Oyarzún AP, Riquelme JA, Garcia-Carvajal I, Díaz-Araya G, García L, Hill JA, Lavandero S. Regulation of cardiac autophagy by insulin-like growth factor 1. IUBMB Life 2013; 65:593-601. [PMID: 23671040 DOI: 10.1002/iub.1172] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 03/22/2013] [Indexed: 12/25/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) signaling is a key pathway in the control of cell growth and survival. Three critical nodes in the IGF-1 signaling pathway have been described in cardiomyocytes: protein kinase Akt/mammalian target of rapamycin (mTOR), Ras/Raf/extracellular signal-regulated kinase (ERK), and phospholipase C (PLC)/inositol 1,4,5-triphosphate (InsP3 )/Ca(2+) . The Akt/mTOR and Ras/Raf/ERK signaling arms govern survival in the settings of cardiac stress and hypertrophic growth. By contrast, PLC/InsP3 /Ca(2+) functions to regulate metabolic adaptability and gene transcription. Autophagy is a catabolic process involved in protein degradation, organelle turnover, and nonselective breakdown of cytoplasmic components during nutrient starvation or stress. In the heart, autophagy is observed in a variety of human pathologies, where it can be either adaptive or maladaptive, depending on the context. We proposed the hypothesis that IGF-1 protects the heart by rescuing the mitochondrial metabolism and the energetics state, reducing cell death and controls the potentially exacerbate autophagic response to nutritional stress. In light of the importance of IGF-1 and autophagy in the heart, we review here IGF-1 signaling and autophagy regulation in the context of cardiomyocyte nutritional stress.
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Affiliation(s)
- Rodrigo Troncoso
- Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
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Bell C, English L, Boulais J, Chemali M, Caron-Lizotte O, Desjardins M, Thibault P. Quantitative proteomics reveals the induction of mitophagy in tumor necrosis factor-α-activated (TNFα) macrophages. Mol Cell Proteomics 2013; 12:2394-407. [PMID: 23674617 DOI: 10.1074/mcp.m112.025775] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Macrophages play an important role in innate and adaptive immunity as professional phagocytes capable of internalizing and degrading pathogens to derive antigens for presentation to T cells. They also produce pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) that mediate local and systemic responses and direct the development of adaptive immunity. The present work describes the use of label-free quantitative proteomics to profile the dynamic changes of proteins from resting and TNF-α-activated mouse macrophages. These analyses revealed that TNF-α activation of macrophages led to the down-regulation of mitochondrial proteins and the differential regulation of several proteins involved in vesicle trafficking and immune response. Importantly, we found that the down-regulation of mitochondria proteins occurred through mitophagy and was specific to TNF-α, as other cytokines such as IL-1β and IFN-γ had no effect on mitochondria degradation. Furthermore, using a novel antigen presentation system, we observed that the induction of mitophagy by TNF-α enabled the processing and presentation of mitochondrial antigens at the cell surface by MHC class I molecules. These findings highlight an unsuspected role of TNF-α in mitophagy and expanded our understanding of the mechanisms responsible for MHC presentation of self-antigens.
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Affiliation(s)
- Christina Bell
- Institute for Research in Immunology and Cancer, Université de Montréal, P.O. Box 6128, Station Centre-ville, Montréal, Québec, Canada H3C 3J7
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178
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Salabei JK, Cummins TD, Singh M, Jones SP, Bhatnagar A, Hill BG. PDGF-mediated autophagy regulates vascular smooth muscle cell phenotype and resistance to oxidative stress. Biochem J 2013; 451:375-88. [PMID: 23421427 PMCID: PMC4040966 DOI: 10.1042/bj20121344] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Vascular injury and chronic arterial diseases result in exposure of VSMCs (vascular smooth muscle cells) to increased concentrations of growth factors. The mechanisms by which growth factors trigger VSMC phenotype transitions remain unclear. Because cellular reprogramming initiated by growth factors requires not only the induction of genes involved in cell proliferation, but also the removal of contractile proteins, we hypothesized that autophagy is an essential modulator of VSMC phenotype. Treatment of VSMCs with PDGF (platelet-derived growth factor)-BB resulted in decreased expression of the contractile phenotype markers calponin and α-smooth muscle actin and up-regulation of the synthetic phenotype markers osteopontin and vimentin. Autophagy, as assessed by LC3 (microtubule-associated protein light chain 3 α; also known as MAP1LC3A)-II abundance, LC3 puncta formation and electron microscopy, was activated by PDGF exposure. Inhibition of autophagy with 3-methyladenine, spautin-1 or bafilomycin stabilized the contractile phenotype. In particular, spautin-1 stabilized α-smooth muscle cell actin and calponin in PDGF-treated cells and prevented actin filament disorganization, diminished production of extracellular matrix, and abrogated VSMC hyperproliferation and migration. Treatment of cells with PDGF prevented protein damage and cell death caused by exposure to the lipid peroxidation product 4-hydroxynonenal. The results of the present study demonstrate a distinct form of autophagy induced by PDGF that is essential for attaining the synthetic phenotype and for survival under the conditions of high oxidative stress found to occur in vascular lesions.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Aldehydes/pharmacology
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Autophagy/drug effects
- Autophagy/genetics
- Biomarkers/metabolism
- Calcium-Binding Proteins/genetics
- Calcium-Binding Proteins/metabolism
- Gene Expression Regulation/drug effects
- Macrolides/pharmacology
- Male
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Osteopontin/genetics
- Osteopontin/metabolism
- Oxidative Stress
- Phenotype
- Platelet-Derived Growth Factor/pharmacology
- Primary Cell Culture
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- Vimentin/genetics
- Vimentin/metabolism
- Calponins
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Affiliation(s)
- Joshua K. Salabei
- Diabetes and Obesity Center and Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202
| | - Timothy D. Cummins
- Diabetes and Obesity Center and Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202
| | - Mahavir Singh
- Diabetes and Obesity Center and Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202
| | - Steven P. Jones
- Diabetes and Obesity Center and Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202
| | - Aruni Bhatnagar
- Diabetes and Obesity Center and Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202
| | - Bradford G. Hill
- Diabetes and Obesity Center and Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202
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179
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Jiang P, Huang Z, Zhao H, Wei T. Hydrogen peroxide impairs autophagic flux in a cell model of nonalcoholic fatty liver disease. Biochem Biophys Res Commun 2013; 433:408-14. [PMID: 23537653 DOI: 10.1016/j.bbrc.2013.02.118] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 02/22/2013] [Indexed: 01/12/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease, but the pathogenesis of NAFLD is not fully clear. The aim of this study was to determine whether autophagy plays a role in the pathogenesis of NAFLD. We found that the levels of autophagy were elevated in hepatoma cells upon exposure to free fatty acids, as confirmed by the increase in the number of autophagosomes. However, exposure of hepatoma cells to H2O2 and TNF-α, two typical "second hit" factors, increased the initiation of autophagy but inhibited the autophagic flux. The inhibition of autophagy sensitized cells to pro-apoptotic stimuli. Taken together, our results suggest that autophagy acts as a protective mechanism in the pathogenesis of NAFLD and that impairment of autophagy might induce more severe lesions of the liver. These findings will be a benefit to the understanding of the pathogenesis of NAFLD and might suggest a strategy for the prevention and cure of NAFLD.
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Affiliation(s)
- Pengtao Jiang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, PR China
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180
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Keller CW, Schmitz M, Münz C, Lünemann JD, Schmidt J. TNF-α upregulates macroautophagic processing of APP/β-amyloid in a human rhabdomyosarcoma cell line. J Neurol Sci 2013; 325:103-7. [DOI: 10.1016/j.jns.2012.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 12/11/2012] [Accepted: 12/11/2012] [Indexed: 01/09/2023]
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181
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Haberzettl P, Hill BG. Oxidized lipids activate autophagy in a JNK-dependent manner by stimulating the endoplasmic reticulum stress response. Redox Biol 2013; 1:56-64. [PMID: 24024137 PMCID: PMC3757667 DOI: 10.1016/j.redox.2012.10.003] [Citation(s) in RCA: 329] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 10/22/2012] [Indexed: 11/30/2022] Open
Abstract
Excessive production of unsaturated aldehydes from oxidized lipoproteins and membrane lipids is a characteristic feature of cardiovascular disease. Our previous studies show that unsaturated lipid peroxidation-derived aldehydes such as 4-hydroxy-trans-2-nonenal (HNE) promote autophagy in rat aortic smooth muscle cells (RASMC). In this study, we examined the mechanism by which HNE induces autophagy. Exposure of RASMC to HNE led to the modification of several proteins, most of which were identified by mass spectrometry and confocal microscopy to be localized to the endoplasmic reticulum (ER). HNE stimulated the phosphorylation of PKR-like ER kinase and eukaryotic initiation factor 2α and increased heme oxygenase-1 (HO-1) abundance. HNE treatment also increased LC3-II formation and the phosphorylation of JNK and p38. Pharmacological inhibition of JNK, but not p38, prevented HNE-induced HO-1 expression and LC3-II formation. Inhibition of JNK increased cell death in HNE-treated cells. Pretreatment with the chemical chaperone phenylbutryic acid prevented LC3-II formation as well as JNK phosphorylation and HO-1 induction. Taken together, these data suggest that autophagic responses triggered by unsaturated aldehydes could be attributed, in part, to ER stress, which stimulates autophagy by a JNK-dependent mechanism and promotes cell survival during oxidative stress.
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Key Words
- 4-hydroxynonenal
- ATF6, activating transcription factor 6
- Autophagy
- DMEM, Delbucco's Eagle Modified Medium
- DMSO, dimethylsulfoxide
- DNPH, 2,4-dinitrophenylhydrazine
- DTT, dithiothreitol
- ECL, enhanced chemiluminescence
- ER, endoplasmic reticulum
- FBS, fetal bovine serum
- Grp, glucose regulated protein
- HEPES, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- HNE, 4-hydroxy-trans-2-nonenal
- HRP, horseradish peroxidase
- IRE, inositol requiring enzyme
- JNK
- JNK, c-jun N-terminal kinase
- LC3, microtubule-associated protein 1 light chain 3
- NP-40, noniodet P40
- Oxidative stress
- PDI, protein disulfide isomerase
- PERK, PKR-like ER kinase
- PVDF, polyvinylidene fluoride
- RASMC, rat aortic smooth muscle cells
- SDS, sodium dodecyl sulfate
- Smooth muscle cells
- UPR, unfolded protein response
- Unfolded protein response
- eIF2α, elongation initiation factor 2 α
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Affiliation(s)
- Petra Haberzettl
- Diabetes and Obesity Center, Institute of Molecular Cardiology, University of Louisville, Louisville, KY, USA
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182
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Macrophage autophagy in atherosclerosis. Mediators Inflamm 2013; 2013:584715. [PMID: 23401644 PMCID: PMC3563164 DOI: 10.1155/2013/584715] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 12/27/2012] [Indexed: 12/14/2022] Open
Abstract
Macrophages play crucial roles in atherosclerotic immune responses. Recent investigation into macrophage autophagy (AP) in atherosclerosis has demonstrated a novel pathway through which these cells contribute to vascular inflammation.
AP is a cellular catabolic process involving the delivery of cytoplasmic contents to the lysosomal machinery for ultimate degradation and recycling. Basal levels of macrophage AP play an essential role in atheroprotection during early atherosclerosis. However, AP becomes dysfunctional in the more advanced stages of the pathology and its deficiency promotes vascular inflammation, oxidative stress, and plaque necrosis. In this paper, we will discuss the role of macrophages and AP in atherosclerosis and the emerging evidence demonstrating the contribution of macrophage AP to vascular pathology. Finally, we will discuss how AP could be targeted for therapeutic utility.
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183
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Upregulation of sestrin 2 expression via JNK pathway activation contributes to autophagy induction in cancer cells. Cell Signal 2013; 25:150-8. [DOI: 10.1016/j.cellsig.2012.09.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 08/02/2012] [Accepted: 09/01/2012] [Indexed: 12/11/2022]
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184
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Rodríguez A, Gómez-Ambrosi J, Catalán V, Rotellar F, Valentí V, Silva C, Mugueta C, Pulido MR, Vázquez R, Salvador J, Malagón MM, Colina I, Frühbeck G. The ghrelin O-acyltransferase-ghrelin system reduces TNF-α-induced apoptosis and autophagy in human visceral adipocytes. Diabetologia 2012; 55:3038-50. [PMID: 22869322 DOI: 10.1007/s00125-012-2671-5] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/25/2012] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Proinflammatory and proapoptotic cytokines such as TNF-α are upregulated in human obesity. We evaluated the association between ghrelin isoforms (acylated and desacyl ghrelin) and TNF-α in obesity and obesity-associated type 2 diabetes, as well as the potential role of ghrelin in the control of apoptosis and autophagy in human adipocytes. METHODS Plasma concentrations of the ghrelin isoforms and TNF-α were measured in 194 participants. Ghrelin and ghrelin O-acyltransferase (GOAT) levels were analysed by western-blot, immunohistochemistry and real-time PCR in 53 biopsies of human omental adipose tissue. We also determined the effect of acylated and desacyl ghrelin (10 to 1,000 pmol/l) on TNF-α-induced apoptosis and autophagy-related molecules in omental adipocytes. RESULTS Circulating concentrations of acylated ghrelin and TNF-α were increased, whereas desacyl ghrelin levels were decreased in obesity-associated type 2 diabetes. Ghrelin and GOAT were produced in omental and subcutaneous adipose tissue. Visceral adipose tissue from obese patients with type 2 diabetes showed higher levels of GOAT, increased adipocyte apoptosis and increased expression of the autophagy-related genes ATG5, BECN1 and ATG7. In differentiating human omental adipocytes, incubation with acylated and desacyl ghrelin reduced TNF-α-induced activation of caspase-8 and caspase-3, and cell death. In addition, acylated ghrelin reduced the basal expression of the autophagy-related genes ATG5 and ATG7, while desacyl ghrelin inhibited the TNF-α-induced increase of ATG5, BECN1 and ATG7 expression. CONCLUSIONS/INTERPRETATION Apoptosis and autophagy are upregulated in human visceral adipose tissue of patients with type 2 diabetes. Acylated and desacyl ghrelin reduce TNF-α-induced apoptosis and autophagy in human visceral adipocytes.
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Affiliation(s)
- A Rodríguez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain
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185
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Tezel G, Yang X, Luo C, Cai J, Powell DW. An astrocyte-specific proteomic approach to inflammatory responses in experimental rat glaucoma. Invest Ophthalmol Vis Sci 2012; 53:4220-33. [PMID: 22570341 DOI: 10.1167/iovs.11-9101] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To delineate astrocyte-mediated inflammatory processes in glaucoma, we analyzed proteomic responses of retinal astrocytes in an experimental rat model using a cell-specific approach. METHODS IOP elevation was induced in rats by hypertonic saline injections into episcleral veins. Enriched samples of astrocytes were isolated through the immunomagnetic cell selection process established originally for retinal ganglion cell (RGC) sampling. Ocular hypertensive and control samples were collected by pooling from rat eyes matched for the cumulative IOP exposure. Protein expression was analyzed complementarily by quantitative two-dimensional capillary liquid chromatography and linear ion trap mass spectrometry (LC-MS/MS) followed by quantitative Western blot analysis and retinal tissue immunolabeling using specific antibodies to selected proteins. RESULTS Following validation of enriched astrocyte samples, LC-MS/MS analysis resulted in the identification of over 2000 proteins with high confidence. Bioinformatic comparison analysis of the high-throughput MS/MS data along with the findings of immunoblotting and immunohistochemistry supported distinct responses of ocular hypertensive astrocytes during the experimental paradigm, which exhibited predominantly cellular activation and immune/inflammatory responses as opposed to activation of cell death signaling in ocular hypertensive RGCs. Inflammatory responses of astrocytes in experimental glaucoma included up-regulation of a number of immune mediators/regulators linked to TNF-α/TNFR signaling, nuclear factor kappa-B (NF-κB) activation, autophagy regulation, and inflammasome assembly. CONCLUSIONS These findings validate an astrocyte-specific approach to quantitatively identify proteomic alterations in experimental glaucoma, and highlight many immune mediators/regulators characteristic of the inflammatory responses of ocular hypertensive astrocytes. By dissecting the complexity of prior data obtained from whole tissue, this pioneering approach should enable astrocyte responses to be defined and new treatments targeting astrocytes to be developed.
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Affiliation(s)
- Gülgün Tezel
- Department of Ophthalmology & Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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186
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Higashi Y, Sukhanov S, Anwar A, Shai SY, Delafontaine P. Aging, atherosclerosis, and IGF-1. J Gerontol A Biol Sci Med Sci 2012; 67:626-39. [PMID: 22491965 PMCID: PMC3348497 DOI: 10.1093/gerona/gls102] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 03/01/2012] [Indexed: 12/18/2022] Open
Abstract
Insulin-like growth factor 1 (IGF-1) is an endocrine and autocrine/paracrine growth factor that circulates at high levels in the plasma and is expressed in most cell types. IGF-1 has major effects on development, cell growth and differentiation, and tissue repair. Recent evidence indicates that IGF-1 reduces atherosclerosis burden and improves features of atherosclerotic plaque stability in animal models. Potential mechanisms for this atheroprotective effect include IGF-1-induced reduction in oxidative stress, cell apoptosis, proinflammatory signaling, and endothelial dysfunction. Aging is associated with increased vascular oxidative stress and vascular disease, suggesting that IGF-1 may exert salutary effects on vascular aging processes. In this review, we will provide a comprehensive update on IGF-1's ability to modulate vascular oxidative stress and to limit atherogenesis and the vascular complications of aging.
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Affiliation(s)
- Yusuke Higashi
- Tulane University Heart & Vascular Institute, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
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187
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Cellular and humoral mechanisms involved in the control of tuberculosis. Clin Dev Immunol 2012; 2012:193923. [PMID: 22666281 PMCID: PMC3362816 DOI: 10.1155/2012/193923] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/06/2012] [Accepted: 03/06/2012] [Indexed: 02/08/2023]
Abstract
Mycobacterium tuberculosis (Mtb) infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs). We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB.
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188
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Rodríguez-Blanco J, Martín V, García-Santos G, Herrera F, Casado-Zapico S, Antolín I, Rodriguez C. Cooperative action of JNK and AKT/mTOR in 1-methyl-4-phenylpyridinium-induced autophagy of neuronal PC12 cells. J Neurosci Res 2012; 90:1850-60. [PMID: 22513717 DOI: 10.1002/jnr.23066] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 02/29/2012] [Accepted: 03/04/2012] [Indexed: 01/01/2023]
Abstract
Parkinson's disease has been widely related to both apoptosis and oxidative stress. Many publications relate the loss of mitochondrial potential to an apoptosis-mediated cell death in different in vivo and in vitro models of this pathology. The present study used the dopaminegic specific neurotoxin 1-methyl-4-phenylpyridinium (MPP(+) ) on neuron-like PC12 cells, which is a well-accepted model of Parkinson's disease. Results showed an early increase in oxidants, which drives the modulation of c-Jun N-terminal kinase (JNK) and AKT/mammalian target of rapamycin (mTOR) pathways, mimicking peroxide treatment. However, the cell death found in neuronal PC12 cells treated with MPP(+) was not a caspase-associated apoptosis. Electron microscopic images illustrated autophagic cell death, which was confirmed by a Beclin-1 and ATG expression increase, accumulation of acidic vesicles, and rescue by an autophagy inhibitor. In conclusion, the boost in oxidants from MPP(+) treatment in neuronal PC12 is modulating both survival (AKT/mTOR) and death (JNK) pathways, which are the perpetrators of an autophagic cell death.
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Affiliation(s)
- Jezabel Rodríguez-Blanco
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
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189
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Schrijvers DM, De Meyer GRY, Martinet W. Autophagy in atherosclerosis: a potential drug target for plaque stabilization. Arterioscler Thromb Vasc Biol 2012; 31:2787-91. [PMID: 22096098 DOI: 10.1161/atvbaha.111.224899] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Evidence is accumulating that autophagy occurs in advanced atherosclerotic plaques. Although there is an almost relentless discovery of molecules that are involved in autophagy, studies of selective autophagy induction or inhibition using knockout mice are just now beginning to reveal its biological significance. Most likely, autophagy safeguards plaque cells against cellular distress, in particular oxidative injury, by degrading the damaged intracellular material. In this way, autophagy is protective and contributes to cellular recovery in an unfavorable environment. Pharmacological approaches have recently been developed to stabilize vulnerable, rupture-prone lesions through induction of autophagy. This approach has proven to be successful in short-term studies. However, how autophagy induction affects processes such as inflammation remains to be elucidated and is currently under investigation. This review highlights the possibilities for exploiting autophagy as a drug target for plaque stabilization.
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Affiliation(s)
- Dorien M Schrijvers
- Division of Pharmacology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.
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190
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Troncoso R, Vicencio JM, Parra V, Nemchenko A, Kawashima Y, Del Campo A, Toro B, Battiprolu PK, Aranguiz P, Chiong M, Yakar S, Gillette TG, Hill JA, Abel ED, Leroith D, Lavandero S. Energy-preserving effects of IGF-1 antagonize starvation-induced cardiac autophagy. Cardiovasc Res 2011; 93:320-9. [PMID: 22135164 DOI: 10.1093/cvr/cvr321] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS Insulin-like growth factor 1 (IGF-1) is known to exert cardioprotective actions. However, it remains unknown if autophagy, a major adaptive response to nutritional stress, contributes to IGF-1-mediated cardioprotection. METHODS AND RESULTS We subjected cultured neonatal rat cardiomyocytes, as well as live mice, to nutritional stress and assessed cell death and autophagic rates. Nutritional stress induced by serum/glucose deprivation strongly induced autophagy and cell death, and both responses were inhibited by IGF-1. The Akt/mammalian target of rapamycin (mTOR) pathway mediated the effects of IGF-1 upon autophagy. Importantly, starvation also decreased intracellular ATP levels and oxygen consumption leading to AMP-activated protein kinase (AMPK) activation; IGF-1 increased mitochondrial Ca(2+) uptake and mitochondrial respiration in nutrient-starved cells. IGF-1 also rescued ATP levels, reduced AMPK phosphorylation and increased p70(S6K) phosphorylation, which indicates that in addition to Akt/mTOR, IGF-1 inhibits autophagy by the AMPK/mTOR axis. In mice harbouring a liver-specific igf1 deletion, which dramatically reduces IGF-1 plasma levels, AMPK activity and autophagy were increased, and significant heart weight loss was observed in comparison with wild-type starved animals, revealing the importance of IGF-1 in maintaining cardiac adaptability to nutritional insults in vivo. CONCLUSION Our data support the cardioprotective actions of IGF-1, which, by rescuing the mitochondrial metabolism and the energetic state of cells, reduces cell death and controls the potentially harmful autophagic response to nutritional challenges. IGF-1, therefore, may prove beneficial to mitigate damage induced by excessive nutrient-related stress, including ischaemic disease in multiple tissues.
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Affiliation(s)
- Rodrigo Troncoso
- Centro de Estudios Moleculares de Célula, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 838-0492, Chile
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191
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Tanaka A, Jin Y, Lee SJ, Zhang M, Kim HP, Stolz DB, Ryter SW, Choi AMK. Hyperoxia-induced LC3B interacts with the Fas apoptotic pathway in epithelial cell death. Am J Respir Cell Mol Biol 2011; 46:507-14. [PMID: 22095627 DOI: 10.1165/rcmb.2009-0415oc] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Epithelial cell death plays a critical role in hyperoxia-induced lung injury. We investigated the involvement of the autophagic marker microtubule-associated protein-1 light chain-3B (LC3B) in epithelial cell apoptosis after hyperoxia. Prolonged hyperoxia (>95% O(2)), which causes characteristic lung injury in mice, activated morphological and biochemical markers of autophagy. Hyperoxia induced the time-dependent expression and conversion of LC3B-I to LC3B-II in mouse lung in vivo and in cultured epithelial cells (Beas-2B, human bronchial epithelial cells) in vitro. Hyperoxia increased autophagosome formation in Beas-2B cells, as evidenced by electron microscopy and increased GFP-LC3 puncta. The augmented LC3B level after hyperoxia was transcriptionally regulated and dependent in part on the c-Jun N-terminal kinase pathway. We hypothesized that LC3B plays a regulatory role in hyperoxia-induced epithelial apoptosis. LC3B siRNA promoted hyperoxia-induced cell death in epithelial cells, whereas overexpression of LC3B conferred cytoprotection after hyperoxia. The autophagic protein LC3B cross-regulated the Fas apoptotic pathway by physically interacting with the components of death-inducing signaling complex. This interaction was mediated by caveolin-1 tyrosine 14, which is a known target of phosphorylation induced by hyperoxia. Taken together, hyperoxia-induced LC3B activation regulates the Fas apoptotic pathway and thus confers cytoprotection in lung epithelial cells. The interaction of LC3B and Fas pathways requires cav-1.
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Affiliation(s)
- Akihiko Tanaka
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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192
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Eid N, Ito Y, Otsuki Y. Enhanced mitophagy in Sertoli cells of ethanol-treated rats: morphological evidence and clinical relevance. J Mol Histol 2011; 43:71-80. [PMID: 22076330 DOI: 10.1007/s10735-011-9372-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 10/27/2011] [Indexed: 12/13/2022]
Abstract
Although chronic ethanol consumption results in Sertoli cell vacuolization and augmented testicular germ cell apoptosis via death receptor and mitochondrial pathways, Sertoli cells are resistant to apoptosis. The aim of this study was to examine whether the activation of autophagy in the Sertoli cells of ethanol-treated rats (ETR) may have a role in their survival. Adult Wistar rats were fed either 5% ethanol in Lieber-DeCarli liquid diet or an isocaloric control diet for 12 weeks. The TUNEL method demonstrated that Sertoli cells were always TUNEL-negative despite the presence of many apoptotic germ cells in ETR, supporting our previous studies. Electron microscopy revealed the presence of large numbers of autophagic vacuoles (AVs) in Sertoli cells of ETR compared to few AVs in control testes. Most of the AVs in Sertoli cells of ETR enveloped and sequestered damaged and abnormally shaped mitochondria, without cytoplasm, indicating mitochondrial autophagy (mitophagy). Immuno-electron microscopy showed the localization of LC3, a specific marker of early AVs (autophagosomes), around AVs sequestering mitochondria in Sertoli cells of ETR. Immunohistochemical staining of LC3 demonstrated a punctate pattern in Sertoli cells of ETR, confirming the formation of autophagosomes, while LC3 puncta were almost absent in control testes. Moreover, increased immunoreactivity of LAMP-2, a lysosomal membrane protein and marker of late AVs (autolysosomes), was mainly observed in Sertoli cells of ETR, with weaker expression in control testes. Via the deletion of pro-apoptotic damaged mitochondria, enhanced Sertoli cell mitophagy in ETR may be an anti-apoptotic mechanism that is essential for spermatogenesis.
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Affiliation(s)
- Nabil Eid
- Department of Anatomy and Cell Biology, Division of Life Sciences, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan
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193
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Zheng YH, Tian C, Meng Y, Qin YW, Du YH, Du J, Li HH. Osteopontin stimulates autophagy via integrin/CD44 and p38 MAPK signaling pathways in vascular smooth muscle cells. J Cell Physiol 2011; 227:127-35. [PMID: 21374592 DOI: 10.1002/jcp.22709] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Osteopontin (OPN) exerts pro-inflammatory effect and is associated with the development of abdominal aortic aneurysm (AAA). However, the molecular mechanism underlying this association remains obscure. In the present study, we compared gene expression profiles of AAA tissues using microarray assay, and found that OPN was the highest expressed gene (>125-fold). Furthermore, the expression of LC3 protein and autophagy-related genes including Atg4b, Beclin1/Atg6, Bnip3, and Vps34 was markedly upregulated in AAA tissues. To investigate the ability of OPN to stimulate autophagy as a potential mechanism involved in the pathogenesis of this disease, we treated vascular smooth muscle cells (SMCs) with OPN, and found that OPN significantly increased the formation of autophagosomes, expression of autophagy-related genes and cell death, whereas blocking the signal by anti-OPN antibody markedly inhibited OPN-induced autophagy and SMC death. Furthermore, inhibition of integrin/CD44 and p38 MAPK signaling pathways markedly abrogated the biological effects of OPN on SMCs. These data for the first time demonstrate that OPN sitmulates autophagy directly through integrin/CD44 and p38 MAPK-mediated pathways in SMCs. Thus, inhibition of OPN-induced autophagy might be a potential therapeutic target in the treatment of AAA disease. J. Cell. Physiol. 227: 127-135, 2012. © 2011 Wiley Periodicals, Inc.
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Heat shock protein 72 enhances autophagy as a protective mechanism in lipopolysaccharide-induced peritonitis in rats. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:2822-34. [PMID: 22001349 DOI: 10.1016/j.ajpath.2011.08.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 08/16/2011] [Accepted: 08/24/2011] [Indexed: 12/13/2022]
Abstract
Peritoneal dialysis-related peritonitis causes the denudation of mesothelial cells and, ultimately, membrane integrity alterations and peritoneal dysfunction. Because heat shock protein 72 (HSP72) confers protection against apoptosis and because autophagy mediates survival in response to cellular stresses, we examined whether autophagy contributes to HSP72-mediated cytoprotection in lipopolysaccharide (LPS)-induced peritonitis. Exposure of cultured peritoneal mesothelial cells to LPS resulted first in autophagy and later, apoptosis. Inhibition of autophagy by 3-methyladenine or Beclin-1 small-interfering RNA sensitized cells to apoptosis and abolished the antiapoptotic effect of HSP72, suggesting that autophagy activation acts as a prosurvival mechanism. Overexpression of HSP72 augmented autophagy through c-Jun N-terminal kinase (JNK) phosphorylation and Beclin-1 up-regulation. Suppression of JNK activity reversed HSP72-mediated Beclin-1 up-regulation and autophagy, indicating that HSP72-mediated autophagy is JNK dependent. In a rat model of LPS-associated peritonitis, autophagy occurred before apoptosis in peritoneum. Up-regulation of HSP72 by geranylgeranylacetone increased autophagy, inhibited apoptosis, and attenuated peritoneal injury, and these effects were blunted by down-regulation of HSP72 with quercetin. Additionally, blocking autophagy by chloroquine promoted apoptosis and aggravated LPS-associated peritoneal dysfunction. Thus, HSP72 protects peritoneum from LPS-induced mesothelial cells injury, at least in part by enhancing JNK activation-dependent autophagy and inhibiting apoptosis. These findings imply that HSP72 induction might be a potential therapy for peritonitis.
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195
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Harris J. Autophagy and cytokines. Cytokine 2011; 56:140-4. [PMID: 21889357 DOI: 10.1016/j.cyto.2011.08.022] [Citation(s) in RCA: 292] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 07/28/2011] [Accepted: 08/07/2011] [Indexed: 12/21/2022]
Abstract
Autophagy is a highly conserved homoeostatic mechanism for the lysosomal degradation of cytosolic constituents, including long-lived macromolecules, organelles and intracellular pathogens. Autophagosomes are formed in response to a number of environmental stimuli, including amino acid deprivation, but also by both host- and pathogen-derived molecules, including toll-like receptor ligands and cytokines. In particular, IFN-γ, TNF-α, IL-1, IL-2, IL-6 and TGF-β have been shown to induce autophagy, while IL-4, IL-10 and IL-13 are inhibitory. Moreover, autophagy can itself regulate the production and secretion of cytokines, including IL-1, IL-18, TNF-α, and Type I IFN. This review discusses the potentially pivotal roles of autophagy in the regulation of inflammation and the coordination of innate and adaptive immune responses.
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Affiliation(s)
- James Harris
- Immunology Research Centre, School of Biochemistry & Immunology, Trinity College Dublin, College Green, Dublin 2, Ireland.
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Shen C, Yan J, Jiang LS, Dai LY. Autophagy in rat annulus fibrosus cells: evidence and possible implications. Arthritis Res Ther 2011; 13:R132. [PMID: 21846367 PMCID: PMC3239374 DOI: 10.1186/ar3443] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/13/2011] [Accepted: 08/16/2011] [Indexed: 01/24/2023] Open
Abstract
INTRODUCTION Programmed cell death of intervertebral disc (IVD) cells plays an important role in IVD degeneration, but the role of autophagy, a closely related cell death event, in IVD cells has not been documented. The current study was designed to investigate the effect of interleukin (IL)-1β on the occurrence of autophagy of rat annulus fibrosus (AF) cells and the interrelationship between autophagy and apoptosis. METHODS Rat AF cells were isolated and exposed, in tissue cultures with or without serum, to IL-1β in different concentrations for 24 hours. Ultrastructural analysis, flow cytometry and lysosomal activity assessment were performed after the in vitro treatment to determine the presence and levels of autophagy. The mRNA expression of autophagy-related proteins (Beclin-1, Bcl-2 and microtubule associated protein 1 light chain 3 (LC3)) were evaluated using real-time PCR. 3-methyladenine (3-MA), a PI3K inhibitor, was used to determine the interaction between autophagy and apoptosis via the suppression of autophagy. RESULTS Autophagy was detected in rat AF cells under serum starvation condition by transmission electron microscopy. PCR and flow cytometry results showed that IL-1β enhanced the autophagy-induction effect of serum deprivation in a dose-dependent manner. However, IL-1β alone failed to induce autophagy in AF cells cultured without serum starvation. When autophagy was suppressed by 3-MA, the apoptosis incidence was increased. Serum supplement also partly reversed the autophagy incidence without affecting the apoptosis incidence in the same cells. CONCLUSIONS IL-1β up-regulates serum deprivation-induced autophagy of AF cells in a dose-dependent manner. Autophagy may represent a protective mechanism against apoptosis in AF cells and IVD degeneration.
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Affiliation(s)
- Chao Shen
- Department of Orthopedic Surgery, Xinhua Hospital, 1665 Kongjiang Road, 200092, Shanghai, China
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Nemchenko A, Chiong M, Turer A, Lavandero S, Hill JA. Autophagy as a therapeutic target in cardiovascular disease. J Mol Cell Cardiol 2011; 51:584-93. [PMID: 21723289 DOI: 10.1016/j.yjmcc.2011.06.010] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/25/2011] [Accepted: 06/15/2011] [Indexed: 12/27/2022]
Abstract
The epidemic of heart failure continues apace, and development of novel therapies with clinical efficacy has lagged. Now, important insights into the molecular circuitry of cardiovascular autophagy have raised the prospect that this cellular pathway of protein quality control may be a target of clinical relevance. Whereas basal levels of autophagy are required for cell survival, excessive levels - or perhaps distinct forms of autophagic flux - contribute to disease pathogenesis. Our challenge will be to distinguish mechanisms that drive adaptive versus maladaptive autophagy and to manipulate those pathways for therapeutic gain. Recent evidence suggests this may be possible. Here, we review the fundamental biology of autophagy and its role in a variety of forms of cardiovascular disease. We discuss ways in which this evolutionarily conserved catabolic mechanism can be manipulated, discuss studies presently underway in heart disease, and provide our perspective on where this exciting field may lead in the future. This article is part of a special issue entitled ''Key Signaling Molecules in Hypertrophy and Heart Failure.''
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Affiliation(s)
- Andriy Nemchenko
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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Chiou WF, Chen CC, Wei BL. 3,4-Di-O-Caffeoylquinic Acid Inhibits Angiotensin-II-Induced Vascular Smooth Muscle Cell Proliferation and Migration by Downregulating the JNK and PI3K/Akt Signaling Pathways. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 2011:634502. [PMID: 19752164 PMCID: PMC3136752 DOI: 10.1093/ecam/nep140] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 08/17/2009] [Indexed: 01/20/2023]
Abstract
We previously reported 3,4-di-O-caffeoylquinic acid (CQC) protected vascular endothelial cells against oxidative stress and restored impaired endothelium-dependent vasodilatation. Here, we further investigated its anti-atherosclerotic effect against angiotensin II (Ang II) evoked proliferation and migration of cultured rat vascular smooth muscle cells (rVSMC). The results showed CQC (1–20 μM) clearly inhibited Ang-II-stimulated BrdU incorporation and cell migration of rVSMC in a concentration-dependent manner but without significant cytotoxicity. Western blot analysis revealed Ang II increased the phosphorylation levels of Akt and mitogen-activated protein kinases (MAPKs;p38, ERK1/2 and JNK) in rVSMC. In the presence of phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin and three individual MAPK inhibitors SB203580, PD98059 and SP600125, both Ang-II-induced cell proliferation and migration were significantly attenuated, although to differing extents, suggesting the PI3K and MAPK signal pathways all participated in regulating rVSMC proliferation and migration. Also, the CQC pretreatment markedly suppressed Ang-II-induced phosphorylation of Akt and JNK rather than ERK1/2, although it failed to affect p38 phosphorylation. In conclusion, our data demonstrate CQC may act by down-regulating Akt, JNK and part of the ERK1/2 pathways to inhibit Ang-II-induced rVSMC proliferation and migration. The anti-atherosclerotic effect of CQC is achieved either by endothelial cells protection or by VSMC proliferation/migration inhibition, suggesting this compound may be useful in preventing vascular diseases.
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Affiliation(s)
- Wen-Fei Chiou
- National Research Institute of Chinese Medicine, Taipei 112, Taiwan
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199
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Sridharan S, Jain K, Basu A. Regulation of autophagy by kinases. Cancers (Basel) 2011; 3:2630-54. [PMID: 24212825 PMCID: PMC3757434 DOI: 10.3390/cancers3022630] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 05/15/2011] [Accepted: 05/27/2011] [Indexed: 12/16/2022] Open
Abstract
Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets.
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Affiliation(s)
- Savitha Sridharan
- Department of Molecular Biology and Immunology, University of North Texas Health Science Center and Institute for Cancer Research, Fort Worth, TX 76107, USA.
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Zhaorigetu S, Yang Z, Toma I, McCaffrey TA, Hu CAA. Apolipoprotein L6, induced in atherosclerotic lesions, promotes apoptosis and blocks Beclin 1-dependent autophagy in atherosclerotic cells. J Biol Chem 2011; 286:27389-98. [PMID: 21646352 DOI: 10.1074/jbc.m110.210245] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inflammatory cytokine-regulated apoptosis and autophagy play pivotal roles in plaque rupture and thrombosis of atherosclerotic lesions. However, the molecular interplay between apoptosis and autophagy in vascular cells has not been investigated. Our prior study showed that human apolipoprotein L6 (ApoL6), a pro-apoptotic BH3-only member of the Bcl-2 family, was one of the downstream targets of interferon-γ (INFγ), which sensitizes atherosclerotic lesion-derived cells (LDCs) to Fas-induced apoptosis. To investigate whether ApoL6 plays a causal role in atherosclerotic apoptosis and autophagy, in this study, we demonstrate that IFNγ treatment itself strongly induces ApoL6, and ApoL6 is highly expressed and partially co-localized with activated caspase 3 in activated smooth muscle cells in atherosclerotic lesions. In addition, overexpression of ApoL6 promotes reactive oxygen species (ROS) generation, caspase activation, and subsequent apoptosis, which can be blocked by pan caspase inhibitor and ROS scavenger. Knockdown of ApoL6 expression by siApoL6 suppresses INFγ- and Fas-mediated apoptosis. Further, ApoL6 binds Bcl-X(L), one of the most abundant anti-death proteins in LDCs. Interestingly, forced ApoL6 expression in LDCs induces degradation of Beclin 1, accumulation of p62, and subsequent attenuation of LC3-II formation and translocation and thus autophagy, whereas siApoL6 treatment reverts the phenotype. Taken together, our results suggest that ApoL6 regulates both apoptosis and autophagy in SMCs. IFNγ-initiated, ApoL6-induced apoptosis in vascular cells may be an important factor causing plaque instability and a potential therapeutic target for treating atherosclerosis and cardiovascular disease.
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Affiliation(s)
- Siqin Zhaorigetu
- Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA
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