-
Autophagy Dec 2021Parkinson disease (PD)-affected brains show consistent endoplasmic reticulum (ER) stress and mitophagic dysfunctions. The mechanisms underlying these perturbations and...
Transcription- and phosphorylation-dependent control of a functional interplay between XBP1s and PINK1 governs mitophagy and potentially impacts Parkinson disease pathophysiology.
Parkinson disease (PD)-affected brains show consistent endoplasmic reticulum (ER) stress and mitophagic dysfunctions. The mechanisms underlying these perturbations and how they are directly linked remain a matter of questions. XBP1 is a transcription factor activated upon ER stress after unconventional splicing by the nuclease ERN1/IREα thereby yielding XBP1s, whereas PINK1 is a kinase considered as the sensor of mitochondrial physiology and a master gatekeeper of mitophagy process. We showed that XBP1s transactivates in human cells, primary cultured neurons and mice brain, and triggered a pro-mitophagic phenotype that was fully dependent of endogenous PINK1. We also unraveled a PINK1-dependent phosphorylation of XBP1s that conditioned its nuclear localization and thereby, governed its transcriptional activity. PINK1-induced XBP1s phosphorylation occurred at residues reminiscent of, and correlated to, those phosphorylated in of sporadic PD-affected brains. Overall, our study delineated a functional loop between XBP1s and PINK1 governing mitophagy that was disrupted in PD condition. 6OHDA: 6-hydroxydopamine; baf: bafilomycin A; BECN1: beclin 1; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CASP3: caspase 3; CCCP: carbonyl cyanide chlorophenylhydrazone; COX8A: cytochrome c oxidase subunit 8A; DDIT3/CHOP: DNA damage inducible transcript 3; EGFP: enhanced green fluorescent protein; ER: endoplasmic reticulum; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; FACS: fluorescence-activated cell sorting; HSPD1/HSP60: heat shock protein family D (Hsp60) member 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MFN2: mitofusin 2; OPTN: optineurin; PD: Parkinson disease; PINK1: PTEN-induced kinase 1; PCR: polymerase chain reaction:; PRKN: parkin RBR E3 ubiquitin protein ligase; XBP1s [p-S61A]: XBP1s phosphorylated at serine 61; XBP1s [p-T48A]: XBP1s phosphorylated at threonine 48; shRNA: short hairpin RNA, SQSTM1/p62: sequestosome 1; TIMM23: translocase of inner mitochondrial membrane 23; TM: tunicamycin; TMRM: tetramethyl rhodamine methylester; TOMM20: translocase of outer mitochondrial membrane 20; Toy: toyocamycin; TP: thapsigargin; UB: ubiquitin; UB (S65): ubiquitin phosphorylated at serine 65; UPR: unfolded protein response, XBP1: X-box binding protein 1; XBP1s: spliced X-box binding protein 1.
Topics: Animals; Autophagy; Endoribonucleases; Mice; Mitophagy; Parkinson Disease; Phosphorylation; Protein Kinases; Protein Serine-Threonine Kinases; X-Box Binding Protein 1
PubMed: 34030589
DOI: 10.1080/15548627.2021.1917129 -
American Journal of Physiology. Renal... Jul 2023Autophagy is a ubiquitous intracellular cytoprotective quality control program that maintains cellular homeostasis by recycling superfluous cytoplasmic components (lipid... (Review)
Review
Autophagy is a ubiquitous intracellular cytoprotective quality control program that maintains cellular homeostasis by recycling superfluous cytoplasmic components (lipid droplets, protein, or glycogen aggregates) and invading pathogens. Mitophagy is a selective form of autophagy that by recycling damaged mitochondrial material, which can extracellularly act as damage-associated molecular patterns, prevents their release. Autophagy and mitophagy are indispensable for the maintenance of kidney homeostasis and exert crucial functions during both physiological and disease conditions. Impaired autophagy and mitophagy can negatively impact the pathophysiological state and promote its progression. Autophagy helps in maintaining structural integrity of the kidney. Mitophagy-mediated mitochondrial quality control is explicitly critical for regulating cellular homeostasis in the kidney. Both autophagy and mitophagy attenuate inflammatory responses in the kidney. An accumulating body of evidence highlights that persistent kidney injury-induced oxidative stress can contribute to dysregulated autophagic and mitophagic responses and cell death. Autophagy and mitophagy also communicate with programmed cell death pathways (apoptosis and necroptosis) and play important roles in cell survival by preventing nutrient deprivation and regulating oxidative stress. Autophagy and mitophagy are activated in the kidney after acute injury. However, their aberrant hyperactivation can be deleterious and cause tissue damage. The findings on the functions of autophagy and mitophagy in various models of chronic kidney disease are heterogeneous and cell type- and context-specific dependent. In this review, we discuss the roles of autophagy and mitophagy in the kidney in regulating inflammatory responses and during various pathological manifestations.
Topics: Humans; Mitophagy; Autophagy; Nephritis; Kidney; Inflammation
PubMed: 37167272
DOI: 10.1152/ajprenal.00012.2023 -
Autophagy May 2021Although macroautophagy/autophagy deficiency causes degenerative diseases, the deletion of essential autophagy genes in adipocytes paradoxically reduces body weight....
Although macroautophagy/autophagy deficiency causes degenerative diseases, the deletion of essential autophagy genes in adipocytes paradoxically reduces body weight. Brown adipose tissue (BAT) plays an important role in body weight regulation and metabolic control. However, the key cellular mechanisms that maintain BAT function remain poorly understood. in this study, we showed that global or brown adipocyte-specific deletion of , a Parkinson disease-related gene involved in selective mitochondrial autophagy (mitophagy), induced BAT dysfunction, and obesity-prone type in mice. Defective mitochondrial function is among the upstream signals that activate the NLRP3 inflammasome. NLRP3 was induced in brown adipocyte precursors (BAPs) from knockout (KO) mice. Unexpectedly, NLRP3 induction did not induce canonical inflammasome activity. Instead, NLRP3 induction led to the differentiation of KO BAPs into white-like adipocytes by increasing the expression of white adipocyte-specific genes and repressing the expression of brown adipocyte-specific genes. deletion in knockout mice reversed BAT dysfunction. Conversely, adipose tissue-specific KO mice showed significantly lower expression of in their BAT. Overall, our data suggest that the role of mitophagy is different from general autophagy in regulating adipose tissue and whole-body energy metabolism. Our results uncovered a new mitochondria-NLRP3 pathway that induces BAT dysfunction. The ability of the knockouts to rescue BAT dysfunction suggests the transcriptional function of NLRP3 as an unexpected, but a quite specific therapeutic target for obesity-related metabolic diseases. ACTB: actin, beta; BAPs: brown adipocyte precursors; BAT: brown adipose tissue; BMDMs: bone marrow-derived macrophages; CASP1: caspase 1; CEBPA: CCAAT/enhancer binding protein (C/EBP), alpha; ChIP: chromatin immunoprecipitation; EE: energy expenditure; HFD: high-fat diet; IL1B: interleukin 1 beta; ITT: insulin tolerance test; KO: knockout; LPS: lipopolysaccharide; NLRP3: NLR family, pyrin domain containing 3; PINK1: PTEN induced putative kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RD: regular diet; ROS: reactive oxygen species; RT: room temperature; UCP1: uncoupling protein 1 (mitochondrial, proton carrier); WT: wild-type.
Topics: Adipocytes; Adipose Tissue, Brown; Animals; Autophagy; Energy Metabolism; Inflammasomes; Mice, Knockout; Mitochondria; Mitophagy; NLR Family, Pyrin Domain-Containing 3 Protein; Reactive Oxygen Species; Mice
PubMed: 32400277
DOI: 10.1080/15548627.2020.1753002 -
IUBMB Life Apr 2022The clearance of damaged or unwanted mitochondria by autophagy (also known as mitophagy) is a mitochondrial quality control mechanism postulated to play an essential... (Review)
Review
The clearance of damaged or unwanted mitochondria by autophagy (also known as mitophagy) is a mitochondrial quality control mechanism postulated to play an essential role in cellular homeostasis, metabolism, and development and confers protection against a wide range of diseases. Proper removal of damaged or unwanted mitochondria is essential for organismal health. Defects in mitophagy are associated with Parkinson's, Alzheimer's disease, cancer, and other degenerative disorders. Mitochondria regulate organismal fitness and longevity via multiple pathways, including cellular senescence, stem cell function, inflammation, mitochondrial unfolded protein response (mtUPR), and bioenergetics. Thus, mitophagy is postulated to be pivotal for maintaining organismal healthspan and lifespan and the protection against aged-related degeneration. In this review, we will summarize recent understanding of the mechanism of mitophagy and aspects of mitochondrial functions. We will focus on mitochondria-related cellular processes that are linked to aging and examine current genetic evidence that supports the hypothesis that mitophagy is a pro-longevity mechanism.
Topics: Autophagy; Longevity; Mitochondria; Mitophagy
PubMed: 34889504
DOI: 10.1002/iub.2585 -
Cells Nov 2023Autophagy is an essential lysosome-mediated degradation pathway that maintains cellular homeostasis and viability in response to various intra- and extracellular... (Review)
Review
Autophagy is an essential lysosome-mediated degradation pathway that maintains cellular homeostasis and viability in response to various intra- and extracellular stresses. Mitophagy is a type of autophagy that is involved in the intricate removal of dysfunctional mitochondria during conditions of metabolic stress. In this review, we describe the multifaceted roles of autophagy and mitophagy in normal physiology and the field of cancer biology. Autophagy and mitophagy exhibit dual context-dependent roles in cancer development, acting as tumor suppressors and promoters. We also discuss the important role of autophagy and mitophagy within the cancer microenvironment and how autophagy and mitophagy influence tumor host-cell interactions to overcome metabolic deficiencies and sustain the activity of cancer-associated fibroblasts (CAFs) in a stromal environment. Finally, we explore the dynamic interplay between autophagy and the immune response in tumors, indicating their potential as immunomodulatory targets in cancer therapy. As the field of autophagy and mitophagy continues to evolve, this comprehensive review provides insights into their important roles in cancer and cancer microenvironment.
Topics: Humans; Mitophagy; Autophagy; Neoplasms; Biology; Tumor Microenvironment
PubMed: 38067169
DOI: 10.3390/cells12232742 -
Autophagy Dec 2021CREG1 (cellular repressor of E1A-stimulated genes 1) is involved in tissue homeostasis and influences macroautophagy/autophagy to protect cardiovascular function....
CREG1 (cellular repressor of E1A-stimulated genes 1) is involved in tissue homeostasis and influences macroautophagy/autophagy to protect cardiovascular function. However, the physiological and pathological role of CREG1 in the skeletal muscle is not clear. Here, we established a skeletal muscle-specific knockout mouse model () by crossing the -floxed mice () with a transgenic line expressing recombinase under the muscle-specific (creatine kinase, muscle) promoter. In mice, the exercise time to exhaustion and running distance were significantly reduced compared to mice at the age of 9 months. In addition, the administration of recombinant (re)CREG1 protein improved the motor function of 9-month-old mice. Moreover, electron microscopy images of 9-month-old mice showed that the mitochondrial quality and quantity were abnormal and associated with increased levels of PINK1 (PTEN induced putative kinase 1) and PRKN/PARKIN (parkin RBR E3 ubiquitin protein ligase) but reduced levels of the mitochondrial proteins PTGS2/COX2, COX4I1/COX4, and TOMM20. These results suggested that CREG1 deficiency accelerated the induction of mitophagy in the skeletal muscle. Mechanistically, gain-and loss-of-function mutations of altered mitochondrial morphology and function, impairing mitophagy in C2C12 cells. Furthermore, HSPD1/HSP60 (heat shock protein 1) (401-573 aa) interacted with CREG1 (130-220 aa) to antagonize the degradation of CREG1 and was involved in the regulation of mitophagy. This was the first time to demonstrate that CREG1 localized to the mitochondria and played an important role in mitophagy modulation that determined skeletal muscle wasting during the growth process or disease conditions.: CCCP: carbonyl cyanide m-chlorophenylhydrazone; CKM: creatine kinase, muscle; COX4I1/COX4: cytochrome c oxidase subunit 4I1; CREG1: cellular repressor of E1A-stimulated genes 1; DMEM: dulbecco's modified eagle medium; DNM1L/DRP1: dynamin 1-like; FCCP: carbonyl cyanide p-trifluoro-methoxy phenyl-hydrazone; HSPD1/HSP60: heat shock protein 1 (chaperonin); IP: immunoprecipitation; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MFF: mitochondrial fission factor; MFN2: mitofusin 2; MYH1/MHC-I: myosin, heavy polypeptide 1, skeletal muscle, adult; OCR: oxygen consumption rate; OPA1: OPA1, mitochondrial dynamin like GTPase; PINK1: PTEN induced putative kinase 1; PPARGC1A/PGC-1α: peroxisome proliferative activated receptor, gamma, coactivator 1 alpha; PRKN/PARKIN: parkin RBR E3 ubiquitin protein ligase; PTGS2/COX2: prostaglandin-endoperoxide synthase 2; RFP: red fluorescent protein; RT-qPCR: real-time quantitative PCR; SQSTM1/p62: sequestosome 1; TFAM: transcription factor A, mitochondrial; TOMM20: translocase of outer mitochondrial membrane 20; VDAC: voltage-dependent anion channel.
Topics: Animals; Autophagy; Mice; Mitochondria; Mitochondrial Membranes; Mitophagy; Muscle, Skeletal
PubMed: 33726618
DOI: 10.1080/15548627.2021.1904488 -
High-protein diets increase cardiovascular risk by activating macrophage mTOR to suppress mitophagy.Nature Metabolism Jan 2020High protein diets are commonly utilized for weight loss, yet have been reported to raise cardiovascular risk. The mechanisms underlying this risk are unknown. Here, we...
High protein diets are commonly utilized for weight loss, yet have been reported to raise cardiovascular risk. The mechanisms underlying this risk are unknown. Here, we show that dietary protein drives atherosclerosis and lesion complexity. Protein ingestion acutely elevates amino acid levels in blood and atherosclerotic plaques, stimulating macrophage mTOR signaling. This is causal in plaque progression as the effects of dietary protein are abrogated in macrophage-specific Raptor-null mice. Mechanistically, we find amino acids exacerbate macrophage apoptosis induced by atherogenic lipids, a process that involves mTORC1-dependent inhibition of mitophagy, accumulation of dysfunctional mitochondria, and mitochondrial apoptosis. Using macrophage-specific mTORC1- and autophagy-deficient mice we confirm this amino acid-mTORC1-autophagy signaling axis in vivo. Our data provide the first insights into the deleterious impact of excessive protein ingestion on macrophages and atherosclerotic progression. Incorporation of these concepts in clinical studies will be important to define the vascular effects of protein-based weight loss regimens.
Topics: Animals; Cardiovascular Diseases; Diet, High-Protein; Heart Disease Risk Factors; Macrophage Activation; Macrophages; Mice; Mitophagy; Plaque, Atherosclerotic; TOR Serine-Threonine Kinases
PubMed: 32128508
DOI: 10.1038/s42255-019-0162-4 -
International Journal of Biological... 2022Triple-negative breast cancer (TNBC) is a massive threat to women's health due to its high morbidity, malignancy, and the refractory, effective therapeutic option of...
Triple-negative breast cancer (TNBC) is a massive threat to women's health due to its high morbidity, malignancy, and the refractory, effective therapeutic option of TNBC is still deficient. The mitochondrial protein showed therapeutic potential on breast cancer, whereas the mechanism and downstream pathway of mitochondrial uncoupling protein 1 (UCP1) was not fully elucidated. We found that UCP1 was negatively regulated to the process of TNBC. Overexpressing UCP1 could inhibit the proliferation and metastasis of TNBC, meanwhile inducing the mitochondrial swelling and activation of mitophagy . Mitophagy activation was then assessed to elucidate whether it was downstream of UCP1 in TNBC metastasis. GSDME is the core of pyroptosis. We found that GSDME was activated in the TNBC cells when UCP1 levels were high. It regulates TNBC cell proliferation potential instead of the apoptosis process and . Our results suggested that UCP1 could inhibit the process of TNBC by activating mitophagy and pyroptosis. Impaired activation of mitophagy weakens the regulation effect of UCP1 on metastasis of TNBC, similar to the impairment of GSDME activation on the proliferation regulation of UCP1 on TNBC. UCP1 might be a novel therapeutic target of TNBC.
Topics: Cell Line, Tumor; Cell Proliferation; Female; Humans; Mitochondrial Proteins; Mitophagy; Pyroptosis; Triple Negative Breast Neoplasms; Uncoupling Protein 1
PubMed: 35541900
DOI: 10.7150/ijbs.68438 -
Nature Communications Oct 2021Liquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins....
Liquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins. However, how phase separation participates in autophagy of dysfunctional mitochondria (mitophagy) remains obscure. We previously discovered that nuclear receptor Nur77 (also called TR3, NGFI-B, or NR4A1) translocates from the nucleus to mitochondria to mediate celastrol-induced mitophagy through interaction with p62/SQSTM1. Here, we show that the ubiquitinated mitochondrial Nur77 forms membraneless condensates capable of sequestrating damaged mitochondria by interacting with the UBA domain of p62/SQSTM1. However, tethering clustered mitochondria to the autophagy machinery requires an additional interaction mediated by the N-terminal intrinsically disordered region (IDR) of Nur77 and the N-terminal PB1 domain of p62/SQSTM1, which confers Nur77-p62/SQSTM1 condensates with the magnitude and liquidity. Our results demonstrate how composite multivalent interaction between Nur77 and p62/SQSTM1 coordinates to sequester damaged mitochondria and to connect targeted cargo mitochondria for autophagy, providing mechanistic insight into mitophagy.
Topics: Animals; Electron Transport Complex IV; Female; Gene Expression Regulation; Genes, Reporter; Green Fluorescent Proteins; HeLa Cells; Humans; Luminescent Proteins; Mice; Mice, Inbred C57BL; Mitochondria; Mitophagy; Nuclear Receptor Subfamily 4, Group A, Member 1; Pentacyclic Triterpenes; Protein Binding; Protein Transport; Recombinant Fusion Proteins; Rheology; Sequestosome-1 Protein; Tumor Necrosis Factor-alpha; Red Fluorescent Protein
PubMed: 34645818
DOI: 10.1038/s41467-021-26295-8 -
Journal of Clinical Hypertension... May 2023Metabolic syndrome (MS), a chronic and non-communicable pathological condition, is characterized by a constellation of clinical manifestations including insulin... (Review)
Review
Metabolic syndrome (MS), a chronic and non-communicable pathological condition, is characterized by a constellation of clinical manifestations including insulin resistance, abdominal adiposity, elevated blood pressure, and perturbations in lipid metabolism. The prevalence of MS has increased dramatically in both developed and developing countries and has now become a truly global problem. Excessive energy intake and concomitant obesity are the main drivers of this syndrome. Mitophagy, in which cells degrade damaged mitochondria through a selective form of autophagy, assumes a crucial position in the regulation of mitochondrial integrity and maintenance. Abnormal mitochondrial quality could result in a spectrum of pathological conditions related to metabolic dysfunction, including metabolic syndrome, cardiovascular ailments, and neoplasms. Recently, there has been a proliferation of research pertaining to the process of mitophagy in the context of MS, and there are various regulatory pathways in MS, including pathways like the ubiquitin-dependent mechanism and receptor-mediated mechanisms, among others. Furthermore, studies have uncovered that the process of mitophagy serves a defensive function in the advancement of Metabolic Syndrome, and inhibition of mitophagy exacerbates the advancement of MS. As a result, the regulation of mitophagy holds great promise as a therapeutic approach in the management of Metabolic Syndrome. In this comprehensive analysis, the authors present a synthesis of the diverse regulatory pathways involved in mitophagy in the context of Metabolic Syndrome, as well as its modes of action in metabolic disorders implicated in the development of MS, Including obesity, insulin resistance (IR), and type 2 diabetes mellitus (T2DM), offering novel avenues for the prophylaxis and therapeutic management of MS.
Topics: Humans; Mitophagy; Metabolic Syndrome; Insulin Resistance; Diabetes Mellitus, Type 2; Hypertension; Obesity
PubMed: 37039609
DOI: 10.1111/jch.14650