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Biochimica Et Biophysica Acta.... Jan 2017Sphingolipids are bioactive lipids found in cell membranes that exert a critical role in signal transduction. In recent years, it has become apparent that sphingolipids... (Review)
Review
Sphingolipids are bioactive lipids found in cell membranes that exert a critical role in signal transduction. In recent years, it has become apparent that sphingolipids participate in growth, senescence, differentiation and apoptosis. The anabolism and catabolism of sphingolipids occur in discrete subcellular locations and consist of a strictly regulated and interconnected network, with ceramide as the central hub. Altered sphingolipid metabolism is linked to several human diseases. Hence, an advanced knowledge of how and where sphingolipids are metabolized is of paramount importance in order to understand the role of sphingolipids in cellular functions. In this review, we provide an overview of sphingolipid metabolism. We focus on the distinct pathways of ceramide synthesis, highlighting the mitochondrial ceramide generation, transport of ceramide to mitochondria and its role in the regulation of mitochondrial-mediated apoptosis, mitophagy and implications to disease. We will discuss unanswered questions and exciting future directions. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
Topics: Animals; Apoptosis; Cell Membrane; Ceramides; Humans; Mitochondria; Mitophagy; Signal Transduction; Sphingolipids
PubMed: 27697478
DOI: 10.1016/j.bbalip.2016.09.019 -
Autophagy Jun 2024Mitophagy involves the selective elimination of defective mitochondria during chemotherapeutic stress to maintain mitochondrial homeostasis and sustain cancer growth....
Mitophagy involves the selective elimination of defective mitochondria during chemotherapeutic stress to maintain mitochondrial homeostasis and sustain cancer growth. Here, we showed that CLU (clusterin) is localized to mitochondria to induce mitophagy controlling mitochondrial damage in oral cancer cells. Moreover, overexpression and knockdown of CLU establish its mitophagy-specific role, where CLU acts as an adaptor protein that coordinately interacts with BAX and LC3 recruiting autophagic machinery around damaged mitochondria in response to cisplatin treatment. Interestingly, CLU triggers class III phosphatidylinositol 3-kinase (PtdIns3K) activity around damaged mitochondria, and inhibition of mitophagic flux causes the accumulation of excessive mitophagosomes resulting in reactive oxygen species (ROS)-dependent apoptosis during cisplatin treatment in oral cancer cells. In parallel, we determined that PPARGC1A/PGC1α (PPARG coactivator 1 alpha) activates mitochondrial biogenesis during CLU-induced mitophagy to maintain the mitochondrial pool. Intriguingly, PPARGC1A inhibition through small interfering RNA (si) and pharmacological inhibitor (SR-18292) treatment counteracts CLU-dependent cytoprotection leading to mitophagy-associated cell death. Furthermore, co-treatment of SR-18292 with cisplatin synergistically suppresses tumor growth in oral cancer xenograft models. In conclusion, CLU and PPARGC1A are essential for sustained cancer cell growth by activating mitophagy and mitochondrial biogenesis, respectively, and their inhibition could provide better therapeutic benefits against oral cancer.
Topics: Humans; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Clusterin; Mitophagy; Mitochondria; Mouth Neoplasms; Animals; Cell Survival; Cell Line, Tumor; Cisplatin; Organelle Biogenesis; Mice; Apoptosis; Mice, Nude; Reactive Oxygen Species; Autophagy
PubMed: 38447939
DOI: 10.1080/15548627.2024.2309904 -
Neurochemistry International Oct 2017Mitochondrial dysfunction contributes to normal aging and a wide spectrum of age-related diseases, including neurodegenerative disorders such as Parkinson's disease and... (Review)
Review
Mitochondrial dysfunction contributes to normal aging and a wide spectrum of age-related diseases, including neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. It is important to maintain a healthy mitochondrial population which is tightly regulated by proteolysis and mitophagy. Mitophagy is a specialized form of autophagy that regulates the turnover of damaged and dysfunctional mitochondria, organelles that function in producing energy for the cell in the form of ATP and regulating energy homeostasis. Mechanistic studies on mitophagy across species highlight a sophisticated and integrated cellular network that regulates the degradation of mitochondria. Strategies directed at maintaining a healthy mitophagy level in aged individuals might have beneficial effects. In this review, we provide an updated mechanistic overview of mitophagy pathways and discuss the role of reduced mitophagy in neurodegeneration. We also highlight potential translational applications of mitophagy-inducing compounds, such as NAD precursors and urolithins.
Topics: Aging; Animals; Autophagy; Humans; Mitochondria; Mitophagy; Neurodegenerative Diseases
PubMed: 28235551
DOI: 10.1016/j.neuint.2017.02.007 -
Cells Feb 2022Mitophagy, which is able to selectively clear excess or damaged mitochondria, plays a vital role in the quality control of mitochondria and the maintenance of normal... (Review)
Review
Mitophagy, which is able to selectively clear excess or damaged mitochondria, plays a vital role in the quality control of mitochondria and the maintenance of normal mitochondrial functions in eukaryotic cells. Mitophagy is involved in many physiological and pathological processes, including apoptosis, innate immunity, inflammation, cell differentiation, signal transduction, and metabolism. Viral infections cause physical dysfunction and thus pose a significant threat to public health. An accumulating body of evidence reveals that some viruses hijack mitophagy to enable immune escape and self-replication. In this review, we systematically summarize the pathway of mitophagy initiation and discuss the functions and mechanisms of mitophagy in infection with classical swine fever virus and other specific viruses, with the aim of providing a theoretical basis for the prevention and control of related diseases.
Topics: Animals; Apoptosis; Immunity, Innate; Mitochondria; Mitophagy; Swine; Virus Diseases
PubMed: 35203359
DOI: 10.3390/cells11040711 -
Endokrynologia Polska 2023Mitophagy is a specific type of autophagy and a selective form of autophagy on a larger scale. It selectively eliminates damaged, misfolded, and surplus mitochondria,... (Review)
Review
Mitophagy is a specific type of autophagy and a selective form of autophagy on a larger scale. It selectively eliminates damaged, misfolded, and surplus mitochondria, particularly those that are cytotoxic, by using autophagic lysosomes. This process is crucial for maintaining a balance of both the quality and quantity of mitochondria, which is necessary for normal cell function and tissue development. However, in certain abnormal situations, such as nutritional deficiencies and hypoxia, the function of mitophagy becomes impaired. This leads to a failure to clear damaged mitochondria in a timely manner, resulting in the production of a large number of reactive oxygen species. These reactive oxygen species further contribute to an inflammatory response and the release of factors that induce apoptosis. Moreover, abnormal mitophagy can also cause mitochondrial dysfunction, disrupt metabolic reprogramming during stress responses, alter cell fate decisions and differentiation, and consequently impact the development and progression of diseases, including cancer. Therefore, mitophagy plays a crucial role in controlling the quality of cancer cells, making it imperative to study its function and impact. Numerous proteins and molecules are involved in the regulation of mitophagy, with Parkin and PTEN-induced kinase 1 (PINK1) serving as key mediators, and the hypoxia-related proteins hypoxia-inducible factor la (HIF1a) and FUN14 domain-containing 1 (FUNDC1) also playing a role. Additionally, proteins such as chromatin licensing and DNA replication factor 1 (CDT-1), insulin-like growth factor 1 (IGF-1), caveolin 1 (Cav-1), and others contribute to the regulation of mitophagy in various ways. This article aims to explore the dual role of mitophagy in tumourigenesis by examining the factors and proteins associated with mitophagy and their regulatory effects. The objective of this review is to provide a new theoretical foundation and direction for cancer treatment.
Topics: Humans; Autophagy; Hypoxia; Mitophagy; Neoplasms; Reactive Oxygen Species
PubMed: 37902014
DOI: 10.5603/ep.95652 -
Identification of mitophagy-related biomarkers and immune infiltration in major depressive disorder.BMC Genomics Apr 2023Major depressive disorder (MDD) is a life-threatening and debilitating mental health condition. Mitophagy, a form of selective autophagy that eliminates dysfunctional...
BACKGROUND
Major depressive disorder (MDD) is a life-threatening and debilitating mental health condition. Mitophagy, a form of selective autophagy that eliminates dysfunctional mitochondria, is associated with depression. However, studies on the relationship between mitophagy-related genes (MRGs) and MDD are scarce. This study aimed to identify potential mitophagy-related biomarkers for MDD and characterize the underlying molecular mechanisms.
METHODS
The gene expression profiles of 144 MDD samples and 72 normal controls were retrieved from the Gene Expression Omnibus database, and the MRGs were extracted from the GeneCards database. Consensus clustering was used to determine MDD clusters. Immune cell infiltration was evaluated using CIBERSORT. Functional enrichment analyses were performed to determine the biological significance of mitophagy-related differentially expressed genes (MR-DEGs). Weighted gene co-expression network analysis, along with a network of protein-protein interactions (PPI), was used to identify key modules and hub genes. Based on the least absolute shrinkage and selection operator analysis and univariate Cox regression analysis, a diagnostic model was constructed and evaluated using receiver operating characteristic curves and validated with training data and external validation data. We reclassified MDD into two molecular subtypes according to biomarkers and evaluated their expression levels.
RESULTS
In total, 315 MDD-related MR-DEGs were identified. Functional enrichment analyses revealed that MR-DEGs were mainly enriched in mitophagy-related biological processes and multiple neurodegenerative disease pathways. Two distinct clusters with diverse immune infiltration characteristics were identified in the 144 MDD samples. MATR3, ACTL6A, FUS, BIRC2, and RIPK1 have been identified as potential biomarkers of MDD. All biomarkers showed varying degrees of correlation with immune cells. In addition, two molecular subtypes with distinct mitophagy gene signatures were identified.
CONCLUSIONS
We identified a novel five-MRG gene signature that has excellent diagnostic performance and identified an association between MRGs and the immune microenvironment in MDD.
Topics: Humans; Depressive Disorder, Major; Mitophagy; Neurodegenerative Diseases; Biomarkers; Cluster Analysis; Actins; Chromosomal Proteins, Non-Histone; DNA-Binding Proteins; RNA-Binding Proteins; Nuclear Matrix-Associated Proteins
PubMed: 37098514
DOI: 10.1186/s12864-023-09304-6 -
Autophagy Apr 2024Intervertebral disc degeneration (IDD) is the most critical pathological factor in the development of low back pain. The maintenance of nucleus pulposus (NP) cell and...
Intervertebral disc degeneration (IDD) is the most critical pathological factor in the development of low back pain. The maintenance of nucleus pulposus (NP) cell and intervertebral disc integrity benefits largely from well-controlled mitochondrial quality, surveilled by mitochondrial dynamics (fission and fusion) and mitophagy, but the outcome is cellular context-dependent that remain to be clarified. Our studies revealed that the loss of NLRX1 is correlated with NP cell senescence and IDD progression, which involve disordered mitochondrial quality. Further using animal and in vitro tissue and cell models, we demonstrated that NLRX1 could facilitate mitochondrial quality by coupling mitochondrial dynamic factors (p-DNM1L, L-OPA1:S-OPA1, OMA1) and mitophagy activity. Conversely, mitochondrial collapse occurred in NLRX1-defective NP cells and switched on the compensatory PINK1-PRKN pathway that led to excessive mitophagy and aggressive NP cell senescence. Mechanistically, NLRX1 was originally shown to interact with zinc transporter SLC39A7 and modulate mitochondrial Zn trafficking via the formation of an NLRX1-SLC39A7 complex on the mitochondrial membrane of NP cells, subsequently orchestrating mitochondrial dynamics and mitophagy. The restoration of NLRX1 function by gene overexpression or pharmacological agonist (NX-13) treatment showed great potential for regulating mitochondrial fission with synchronous fusion and mitophagy, thus sustaining mitochondrial homeostasis, ameliorating NP cell senescence and rejuvenating intervertebral discs. Collectively, our findings highlight a working model whereby the NLRX1-SLC39A7 complex coupled mitochondrial dynamics and mitophagy activity to surveil and target damaged mitochondria for degradation, which determines the beneficial function of the mitochondrial surveillance system and ultimately rejuvenates intervertebral discs. 3-MA: 3-methyladenine; Baf-A: bafilomycin A; CDKN1A/p21: cyclin dependent kinase inhibitor 1A; CDKN2A/p16: cyclin dependent kinase inhibitor 2A; DNM1L/DRP1: dynamin 1 like; EdU: 5-Ethynyl-2'-deoxyuridine; HE: hematoxylin-eosin; IDD: intervertebral disc degeneration; IL1B/IL-1β: interleukin 1 beta; IL6: interleukin 6; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MKI67/Ki67: marker of proliferation Ki-67; LBP: low back pain; MMP: mitochondrial membrane potential; MFN1: mitofusin 1; MFN2: mitofusin 2; MFF: mitochondrial fission factor; NP: nucleus pulposus; NLRX1: NLR family member X1; OMA1: OMA1 zinc metallopeptidase; OPA1: OPA1 mitochondrial dynamin like GTPase; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxidative species; SASP: senescence-associated secretory phenotype; SA-GLB1/β-gal: senescence-associated galactosidase beta 1; SO: safranin o; TBHP: tert-butyl hydroperoxide; TP53/p53: tumor protein p53; SLC39A7/ZIP7: solute carrier family 39 member 7; TOMM20: translocase of outer mitochondrial membrane 20; TIMM23: translocase of inner mitochondrial membrane 23.
Topics: Mitophagy; Mitochondrial Dynamics; Mitochondria; Animals; Zinc; Intervertebral Disc Degeneration; Mitochondrial Proteins; Cellular Senescence; Nucleus Pulposus; Humans; Intervertebral Disc; Cation Transport Proteins; Mice; Protein Kinases
PubMed: 37876250
DOI: 10.1080/15548627.2023.2274205 -
Mitochondrion Mar 2020Autophagy is a ubiquitous homeostatic mechanism for the degradation or turnover of cellular components. Degradation of mitochondria via autophagy (mitophagy) is involved... (Review)
Review
Autophagy is a ubiquitous homeostatic mechanism for the degradation or turnover of cellular components. Degradation of mitochondria via autophagy (mitophagy) is involved in a number of physiological processes including cellular homeostasis, differentiation and aging. Upon stress or injury, mitophagy prevents the accumulation of damaged mitochondria and the increased steady state levels of reactive oxygen species leading to oxidative stress and cell death. A number of human diseases, particularly neurodegenerative disorders, have been linked to the dysregulation of mitophagy. In this mini-review, we aimed to review the molecular mechanisms involved in the regulation of mitophagy and their relationship with redox signaling and oxidative stress.
Topics: Aging; Humans; Mitochondria; Mitochondrial Diseases; Mitochondrial Dynamics; Mitophagy; Neurodegenerative Diseases; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species
PubMed: 31972372
DOI: 10.1016/j.mito.2020.01.002 -
Journal of Neuroinflammation Nov 2020Intermittent hypoxia (IH) caused by obstructive sleep apnea (OSA) leads to neuroinflammation. Pinocembrin has been shown to have neuroprotective effects, while the...
BACKGROUND
Intermittent hypoxia (IH) caused by obstructive sleep apnea (OSA) leads to neuroinflammation. Pinocembrin has been shown to have neuroprotective effects, while the therapeutic functions under IH condition are still unknown.
METHODS
An OSA model was established by CIH exposure inside custom-made chambers. C57BL/6 mice were intraperitoneally injected with pinocembrin (40 mg/kg, i.p.) or vehicle (PBS containing 5% povidone; i.p.), and the changes of behavior on mice were detected by the Morris water maze test. Immunohistochemical staining, western blotting, immunofluorescence assays, and immunoprecipitation were used to investigate the association between NLRP3 inflammasome and BNIP3-dependent mitophagy. The mitochondrial morphology and mitophagosomes were detected under a transmission electron microscope. The detrimental effects of IH were tested by annexin V-FITC/PI staining, Mito SOX Red staining, and JC-1 mitochondrial membrane potential assay.
RESULTS
In this study, our observations in vivo indicated that the administration of pinocembrin can restore spatial learning and memory ability and reduce neuronal apoptosis and hippocampal inflammation. Pinocembrin treatment significantly inhibited the formation of NLRP3 inflammasome and infiltration of microglia and enhanced BNIP3-mediated mitophagy in the hippocampus of IH mice. Additionally, our in vitro results show that pinocembrin protects microglial cells against IH-induced cytotoxicity by activating BNIP3-dependent mitophagy through the JNK-ERK signaling pathway.
CONCLUSIONS
In summary, our findings demonstrated that pinocembrin can act as a potential therapeutic strategy for IH-induced neuroinflammation.
Topics: Animals; Flavanones; Hypoxia; Inflammation; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mitochondria; Mitochondrial Proteins; Mitophagy; Sleep Apnea Syndromes
PubMed: 33176803
DOI: 10.1186/s12974-020-02014-w -
Brain : a Journal of Neurology Dec 2022This scientific commentary refers to ‘Regulation of mitophagy by the NSL complex underlies genetic risk for Parkinson's disease at 16q11.2 and MAPT H1 loci’ by...
This scientific commentary refers to ‘Regulation of mitophagy by the NSL complex underlies genetic risk for Parkinson's disease at 16q11.2 and MAPT H1 loci’ by Soutar . (https://doi.org/10.1093/brain/awac325); and ‘DJ-1 is an essential downstream mediator in PINK1/parkin-dependent mitophagy’ by Imberechts (https://doi.org/10.1093/brain/awac313).
Topics: Humans; Mitophagy; Parkinson Disease; Ubiquitin-Protein Ligases; Protein Kinases
PubMed: 36319596
DOI: 10.1093/brain/awac405