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Abstract
Non-alcoholic fatty liver disease (NAFLD) is a growing cause of chronic liver disease worldwide. It is characterised by steatosis, liver inflammation, hepatocellular injury and progressive fibrosis. Several preclinical models (dietary and genetic animal models) of NAFLD have deepened our understanding of its aetiology and pathophysiology. Despite the progress made, there are currently no effective treatments for NAFLD. In this review, we will provide an update on the known molecular pathways involved in the pathophysiology of NAFLD and on ongoing studies of new therapeutic targets.
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Key Words
- ACC, acetyl-CoA carboxylase
- ASK1, apoptosis signal-regulating kinase 1
- CAP, controlled attenuation parameter
- ChREBP
- ChREBP, carbohydrate responsive element–binding protein
- FAS, fatty acid synthase
- FFA, free fatty acid
- FGF21, fibroblast growth factor-21
- FXR
- FXR, farnesoid X receptor
- GGT, gamma glutamyltransferase
- HCC, hepatocellular carcinoma
- HFD, high-fat diet
- HSC, hepatic stellate cells
- HSL, hormone-sensitive lipase
- HVPG, hepatic venous pressure gradient
- IL-, interleukin-
- JNK, c-Jun N-terminal kinase
- LXR
- LXR, liver X receptor
- MCD, methionine- and choline-deficient
- MUFA, monounsaturated fatty acids
- NAFLD
- NAFLD, non-alcoholic fatty liver disease
- NASH
- NASH, non-alcoholic steatohepatitis
- NEFA
- NEFA, non-esterified fatty acid
- PPARα
- PPARα, peroxisome proliferator-activated receptor-α
- PUFAs, polyunsaturated fatty acids
- PY, persons/years
- Phf2, histone demethylase plant homeodomain finger 2
- RCT, randomised controlled trial
- SCD1, stearoyl-CoA desaturase-1
- SFA, saturated fatty acid
- SREBP-1c
- SREBP-1c, sterol regulatory element–binding protein-1c
- TCA, tricarboxylic acid
- TLR4, Toll-like receptor 4
- TNF-α, tumour necrosis factor-α
- VLDL, very low-density lipoprotein
- animal models
- glucotoxicity
- lipotoxicity
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Affiliation(s)
- Lucia Parlati
- Université de Paris, Institut Cochin, CNRS, INSERM, F- 75014 Paris, France.,Hôpital Cochin, 24, rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Marion Régnier
- UCLouvain, Université catholique de Louvain, Walloon Excellence in Life Sciences and BIOtechnology, Louvain Drug Research Institute, Metabolism and Nutrition Research Group, Brussels, Belgium
| | - Hervé Guillou
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse 31027, France
| | - Catherine Postic
- Université de Paris, Institut Cochin, CNRS, INSERM, F- 75014 Paris, France
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Abstract
Mitochondria are functionally versatile organelles. In addition to their conventional role of meeting the cell's energy requirements, mitochondria also actively regulate innate immune responses against infectious and sterile insults. Components of mitochondria, when released or exposed in response to dysfunction or damage, can be directly recognized by receptors of the innate immune system and trigger an immune response. In addition, despite initiation that may be independent from mitochondria, numerous innate immune responses are still subject to mitochondrial regulation as discrete steps of their signaling cascades occur on mitochondria or require mitochondrial components. Finally, mitochondrial metabolites and the metabolic state of the mitochondria within an innate immune cell modulate the precise immune response and shape the direction and character of that cell's response to stimuli. Together, these pathways result in a nuanced and very specific regulation of innate immune responses by mitochondria.
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Key Words
- ASC, Apoptosis Associated Speck like protein containing CARD
- ASK1, apoptosis signal-regulating kinase 1
- ATP, adenosine tri-phosphate
- CAPS, cryopyrin associated periodic syndromes
- CARD, caspase activation and recruitment domain
- CL, cardiolipin
- CLR, C-type lectin receptor
- CREB, cAMP response element binding protein
- Cgas, cyclic GMP-AMP synthase
- DAMP, damage associated molecular pattern
- ESCIT, evolutionarily conserved signaling intermediate in the toll pathway
- ETC, electron transport chain
- FPR, formyl peptide receptor
- HIF, hypoxia-inducible factor
- HMGB1, high mobility group box protein 1
- IFN, interferon
- IL, interleukin
- IRF, interferon regulatory factor
- JNK, cJUN NH2-terminal kinase
- LPS, lipopolysaccharide
- LRR, leucine rich repeat
- MAPK, mitogen-activated protein kinase
- MARCH5, membrane-associated ring finger (C3HC4) 5
- MAVS, mitochondrial antiviral signaling
- MAVS, mitochondrial antiviral signaling protein
- MFN1/2, mitofusin
- MOMP, mitochondrial outer membrane permeabilization
- MPT, mitochondrial permeability transition
- MyD88, myeloid differentiation primary response 88
- NADH, nicotinamide adenine dinucleotide
- NBD, nucleotide binding domain
- NFκB, Nuclear factor κ B
- NLR, NOD like receptor
- NOD, nucleotide-binding oligomerization domain
- NRF2, nuclear factor erythroid 2-related factor 2
- PAMP, pathogen associated molecular pattern
- PPAR, peroxisome proliferator-accelerated receptor
- PRRs, pathogen recognition receptors
- RIG-I, retinoic acid inducible gene I
- RLR, retinoic acid inducible gene like receptor
- ROS, reactive oxygen species
- STING, stimulator of interferon gene
- TAK1, transforming growth factor-β-activated kinase 1
- TANK, TRAF family member-associated NFκB activator
- TBK1, TANK Binding Kinase 1
- TCA, Tri-carboxylic acid
- TFAM, mitochondrial transcription factor A
- TLR, Toll Like Receptor
- TRAF6, tumor necrosis factor receptor-associated factor 6
- TRIF, TIR-domain-containing adapter-inducing interferon β
- TUFM, Tu translation elongation factor.
- fMet, N-formylated methionine
- mROS, mitochondrial ROS
- mtDNA, mitochondrial DNA
- n-fp, n-formyl peptides
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3
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Abstract
Mitochondria are functionally versatile organelles. In addition to their conventional role of meeting the cell's energy requirements, mitochondria also actively regulate innate immune responses against infectious and sterile insults. Components of mitochondria, when released or exposed in response to dysfunction or damage, can be directly recognized by receptors of the innate immune system and trigger an immune response. In addition, despite initiation that may be independent from mitochondria, numerous innate immune responses are still subject to mitochondrial regulation as discrete steps of their signaling cascades occur on mitochondria or require mitochondrial components. Finally, mitochondrial metabolites and the metabolic state of the mitochondria within an innate immune cell modulate the precise immune response and shape the direction and character of that cell's response to stimuli. Together, these pathways result in a nuanced and very specific regulation of innate immune responses by mitochondria.
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Key Words
- ASC, Apoptosis Associated Speck like protein containing CARD
- ASK1, apoptosis signal-regulating kinase 1
- ATP, adenosine tri-phosphate
- CAPS, cryopyrin associated periodic syndromes
- CARD, caspase activation and recruitment domain
- CL, cardiolipin
- CLR, C-type lectin receptor
- CREB, cAMP response element binding protein
- Cgas, cyclic GMP-AMP synthase
- DAMP, damage associated molecular pattern
- ESCIT, evolutionarily conserved signaling intermediate in the toll pathway
- ETC, electron transport chain
- FPR, formyl peptide receptor
- HIF, hypoxia-inducible factor
- HMGB1, high mobility group box protein 1
- IFN, interferon
- IL, interleukin
- IRF, interferon regulatory factor
- JNK, cJUN NH2-terminal kinase
- LPS, lipopolysaccharide
- LRR, leucine rich repeat
- MAPK, mitogen-activated protein kinase
- MARCH5, membrane-associated ring finger (C3HC4) 5
- MAVS, mitochondrial antiviral signaling
- MAVS, mitochondrial antiviral signaling protein
- MFN1/2, mitofusin
- MOMP, mitochondrial outer membrane permeabilization
- MPT, mitochondrial permeability transition
- MyD88, myeloid differentiation primary response 88
- NADH, nicotinamide adenine dinucleotide
- NBD, nucleotide binding domain
- NFκB, Nuclear factor κ B
- NLR, NOD like receptor
- NOD, nucleotide-binding oligomerization domain
- NRF2, nuclear factor erythroid 2-related factor 2
- PAMP, pathogen associated molecular pattern
- PPAR, peroxisome proliferator-accelerated receptor
- PRRs, pathogen recognition receptors
- RIG-I, retinoic acid inducible gene I
- RLR, retinoic acid inducible gene like receptor
- ROS, reactive oxygen species
- STING, stimulator of interferon gene
- TAK1, transforming growth factor-β-activated kinase 1
- TANK, TRAF family member-associated NFκB activator
- TBK1, TANK Binding Kinase 1
- TCA, Tri-carboxylic acid
- TFAM, mitochondrial transcription factor A
- TLR, Toll Like Receptor
- TRAF6, tumor necrosis factor receptor-associated factor 6
- TRIF, TIR-domain-containing adapter-inducing interferon β
- TUFM, Tu translation elongation factor.
- fMet, N-formylated methionine
- mROS, mitochondrial ROS
- mtDNA, mitochondrial DNA
- n-fp, n-formyl peptides
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Affiliation(s)
- Balaji Banoth
- Women's Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Suzanne L Cassel
- Women's Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
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Abstract
The development and progression of melanoma have been attributed to independent or combined genetic and epigenetic events. There has been remarkable progress in understanding melanoma pathogenesis in terms of genetic alterations. However, recent studies have revealed a complex involvement of epigenetic mechanisms in the regulation of gene expression, including methylation, chromatin modification and remodeling, and the diverse activities of non-coding RNAs. The roles of gene methylation and miRNAs have been relatively well studied in melanoma, but other studies have shown that changes in chromatin status and in the differential expression of long non-coding RNAs can lead to altered regulation of key genes. Taken together, they affect the functioning of signaling pathways that influence each other, intersect, and form networks in which local perturbations disturb the activity of the whole system. Here, we focus on how epigenetic events intertwine with these pathways and contribute to the molecular pathogenesis of melanoma.
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Key Words
- 5hmC, 5-hydroxymethylcytosine
- 5mC, 5-methylcytosine
- ACE, angiotensin converting enzyme
- ANCR, anti-differentiation non-coding RNA
- ANRIL, antisense noncoding RNA in INK4 locus
- ASK1, apoptosis signal-regulating kinase 1
- ATRA, all-trans retinoic acid
- BANCR, BRAF-activated non-coding RNA
- BCL-2, B-cell lymphoma 2
- BRAF, B-Raf proto-oncogene, serine/threonine kinase
- BRG1, ATP-dependent helicase SMARCA4
- CAF-1, chromatin assembly factor-1
- CBX7, chromobox homolog 7
- CCND1, cyclin D1
- CD28, cluster of differentiation 28
- CDK, cyclin-dependent kinase
- CDKN2A/B, cyclin-dependent kinase inhibitor 2A/B
- CHD8, chromodomain-helicase DNA-binding protein 8
- CREB, cAMP response element-binding protein
- CUDR, cancer upregulated drug resistant
- Cdc6, cell division cycle 6
- DNA methylation/demethylation
- DNMT, DNA methyltransferase
- EMT, epithelial-mesenchymal transition
- ERK, extracellular signal-regulated kinase
- EZH2, enhancer of zeste homolog 2
- GPCRs, G-protein coupled receptors
- GSK3a, glycogen synthase kinase 3 α
- GWAS, genome-wide association study
- HDAC, histone deacetylase
- HOTAIR, HOX antisense intergenic RNA
- IAP, inhibitor of apoptosis
- IDH2, isocitrate dehydrogenase
- IFN, interferon, interleukin 23
- JNK, Jun N-terminal kinase
- Jak/STAT, Janus kinase/signal transducer and activator of transcription
- MAFG, v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog G
- MALAT1, metastasis-associated lung adenocarcinoma transcript 1
- MAPK, mitogen-activated protein kinase
- MC1R, melanocortin-1 receptor
- MGMT, O6-methylguanine-DNA methyltransferase
- MIF, macrophage migration inhibitory factor
- MITF, microphthalmia-associated transcription factor
- MRE, miRNA recognition element
- MeCP2, methyl CpG binding protein 2
- NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells
- NOD, nucleotide-binding and oligomerization domain
- PBX, pre-B-cell leukemia homeobox
- PEDF, pigment epithelium derived factor
- PI3K, phosphatidylinositol-4, 5-bisphosphate 3-kinase
- PIB5PA, phosphatidylinositol-4, 5-biphosphate 5-phosphatase A
- PKA, protein kinase A
- PRC, polycomb repressor complex
- PSF, PTB associated splicing factor
- PTB, polypyrimidine tract-binding
- PTEN, phosphatase and tensin homolog
- RARB, retinoic acid receptor-β2
- RASSF1A, Ras association domain family 1A
- SETDB1, SET Domain, bifurcated 1
- SPRY4, Sprouty 4
- STAU1, Staufen1
- SWI/SNF, SWItch/Sucrose Non-Fermentable
- TCR, T-cell receptor
- TET, ten eleven translocase
- TGF β, transforming growth factor β
- TINCR, tissue differentiation-inducing non-protein coding RNA
- TOR, target of rapamycin
- TP53, tumor protein 53
- TRAF6, TNF receptor-associated factor 6
- UCA1, urothelial carcinoma-associated 1
- ceRNA, competitive endogenous RNAs
- chromatin modification
- chromatin remodeling
- epigenetics
- gene regulation
- lncRNA, long ncRNA
- melanoma
- miRNA, micro RNA
- ncRNA, non-coding RNA
- ncRNAs
- p14ARF, p14 alternative reading frame
- p16INK4a, p16 inhibitor of CDK4
- pRB, retinoblastoma protein
- snoRNA, small nucleolar RNA
- α-MSHm, α-melanocyte stimulating hormone
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Affiliation(s)
- Debina Sarkar
- a Auckland Cancer Society Research Center ; University of Auckland ; Auckland , New Zealand
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Seong HA, Manoharan R, Ha H. A crucial role for the phosphorylation of STRAP at Ser(188) by MPK38 in STRAP-dependent cell death through ASK1, TGF-β, p53, and PI3K/PDK1 signaling pathways. Cell Cycle 2015; 13:3357-74. [PMID: 25485581 DOI: 10.4161/15384101.2014.952165] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Serine-threonine kinase receptor-associated protein (STRAP) is a TGF-β receptor-interacting protein that participates in the regulation of cell proliferation and cell death in response to various stresses. Here, we demonstrate that STRAP phosphorylation plays an important role in determining the pro- or anti-apoptotic function of STRAP. Murine protein serine/threonine kinase 38 (MPK38) phosphorylates STRAP at Ser(188) via direct interaction. Complex formation between STRAP and MPK38 is mediated by Cys(152) and Cys(270) of STRAP and Cys(339) and Cys(377) of MPK38, suggesting the redox dependency of this interaction. MPK38-mediated STRAP Ser(188) phosphorylation contributes to the pro-apoptotic function of STRAP by modulating key steps in STRAP-dependent ASK1, TGF-β, p53, and PI3K/PDK1 signaling pathways. Moreover, knockdown of endogenous MPK38 using an inducible MPK38 shRNA system and in vivo activation of MPK38 by treatment of HEK293 and STRAP-null MEF cells with 1-chloro-2,4-dinitrobenzene (DNCB), a specific inhibitor of Trx reductase, provide evidence that STRAP Ser(188) phosphorylation plays a key role in STRAP-dependent cell death. Adenoviral delivery of MPK38 in mice also demonstrates that STRAP Ser(188) phosphorylation in the liver is tightly associated with cell death and proliferation through ASK1, TGF-β, p53, and PI3K/PDK1 pathways, resulting in apoptotic cell death.
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Affiliation(s)
- Hyun-A Seong
- a Department of Biochemistry; School of Life Sciences ; Chungbuk National University ; Cheongju , Republic of Korea
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Lopert P, Patel M. Brain mitochondria from DJ-1 knockout mice show increased respiration-dependent hydrogen peroxide consumption. Redox Biol 2014; 2:667-72. [PMID: 24936441 DOI: 10.1016/j.redox.2014.04.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 04/18/2014] [Accepted: 04/22/2014] [Indexed: 11/20/2022] Open
Abstract
Mutations in the DJ-1 gene have been shown to cause a rare autosomal-recessive genetic form of Parkinson's disease (PD). The function of DJ-1 and its role in PD development has been linked to multiple pathways, however its exact role in the development of PD has remained elusive. It is thought that DJ-1 may play a role in regulating reactive oxygen species (ROS) formation and overall oxidative stress in cells through directly scavenging ROS itself, or through the regulation of ROS scavenging systems such as glutathione (GSH) or thioredoxin (Trx) or ROS producing complexes such as complex I of the electron transport chain. Previous work in this laboratory has demonstrated that isolated brain mitochondria consume H2O2 predominantly by the Trx/Thioredoxin Reductase (TrxR)/Peroxiredoxin (Prx) system in a respiration dependent manner (Drechsel et al., Journal of Biological Chemistry, 2010). Therefore we wanted to determine if mitochondrial H2O2 consumption was altered in brains from DJ-1 deficient mice (DJ-1(-/-)). Surprisingly, DJ-1(-/-) mice showed an increase in mitochondrial respiration-dependent H2O2 consumption compared to controls. To determine the basis of the increased H2O2 consumption in DJ1(-/-) mice, the activities of Trx, Thioredoxin Reductase (TrxR), GSH, glutathione disulfide (GSSG) and glutathione reductase (GR) were measured. Compared to control mice, brains from DJ-1(-/-) mice showed an increase in (1) mitochondrial Trx activity, (2) GSH and GSSG levels and (3) mitochondrial glutaredoxin (GRX) activity. Brains from DJ-1(-/-) mice showed a decrease in mitochondrial GR activity compared to controls. The increase in the enzymatic activities of mitochondrial Trx and total GSH levels may account for the increased H2O2 consumption observed in the brain mitochondria in DJ-1(-/-) mice perhaps as an adaptive response to chronic DJ-1 deficiency.
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Key Words
- 4-HNE, 4-hydroxyl-2-nonenal
- 6OHDA, 6-hydroxydopamine
- ASK1, apoptosis signal-regulating kinase 1
- BSA, Bovin Serum Albumin
- Cox IV, complex IV
- DA, dopaminergic
- DJ-1
- DJ1-/-, DJ-1 knockout
- GR, glutathione reductase
- GRX, glutaredoxin
- GSH, reduced glutathione
- GSSG, oxidized glutathione
- Gpx, glutathione peroxidase
- H2O2, hydrogen peroxide
- HEDS, 2-hydroxyethyl disulfide
- MEF, mouse embryonic fibroblasts
- MPTP, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- Mitochondria
- Nrf2, nuclear factor erythroid 2-related factor
- Oxidative stress
- PD, Parkinson’s disease
- PQ, paraquat
- Parkinson’s disease
- Prx, peroxiredoxin
- ROS, reactive oxygen species
- SNpc, substantia nigra pars compacta
- TH, tyrosine hydroxylase
- Thioredoxin
- Thioredoxin reductase
- Trx, thioredoxin
- Trx1, cytosolic trx
- Trx2, mitochondrial trx
- TrxR, thioredoxin reductase
- TrxR1, cytosolic TrxR
- TrxR2, mitochondrial Trx
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