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Cell Death & Disease Jan 2020Excessive mitochondrial fission acts as a pro-proliferative marker in some cancers and organ fibrosis; its potential role in renal fibroblast activation and fibrogenesis...
Excessive mitochondrial fission acts as a pro-proliferative marker in some cancers and organ fibrosis; its potential role in renal fibroblast activation and fibrogenesis has never been investigated. Here, we showed more pronounced fragmented mitochondria in fibrotic than in non-fibrotic renal fibroblast in humans and mice. In a mouse model of obstructive nephropathy, phosphorylation of Drp1 at serine 616 (p-Drp1S616) and acetylation of H3K27(H3K27ac) was increased in fibrotic kidneys; pharmacological inhibition of mitochondrial fission by mdivi-1 substantially reduced H3K27ac levels, fibroblasts accumulation, and interstitial fibrosis. Moreover, mdivi-1 treatment was able to attenuate the established renal fibrosis. In cultured renal interstitial fibroblasts, targeting Drp1 using pharmacological inhibitor or siRNA suppressed TGF-β1-elicited cell activation and proliferation, as evidenced by inhibiting expression of α-smooth muscle actin (α-SMA) and collagen I, as well as by reducing DNA synthesis. In contrast, Drp1 deletion enhanced cell apoptosis, along with decreased mitochondrial fragmentation, mtROS elevation, and glycolytic shift upon TGF-β1 stimulation. In Drp1 deletion fibroblasts, re-expression of wild-type Drp1 rather than Drp1S616A mutant restores the reduction of TGF-β-induced-Drp1 phosphorylation, H3K27ac, and cell activation. Moreover, TGF-β1 treatment increased the enrichment of H3K27ac at the promoters of α-SMA and PCNA, which was reversed in Drp1-knockdown fibroblasts co-transfected with empty vector or Drp1S616A, but not wild-type Drp1. Collectively, our results imply that inhibiting p-Drp1S616-mediated mitochondrial fission attenuates fibroblast activation and proliferation in renal fibrosis through epigenetic regulation of fibrosis-related genes transcription and may serve as a therapeutic target for retarding progression of chronic kidney disease.
Topics: Animals; Apoptosis; Cell Proliferation; Dynamins; Fibroblasts; Fibrosis; Gene Knockdown Techniques; Histones; Humans; Kidney; Lysine; Male; Mice, Inbred C57BL; Mitochondria; Mitochondrial Dynamics; Phosphorylation; Phosphoserine; Proliferating Cell Nuclear Antigen; Promoter Regions, Genetic; Protein Binding; Rats; Reactive Oxygen Species; Transforming Growth Factor beta1
PubMed: 31949126
DOI: 10.1038/s41419-019-2218-5 -
The EMBO Journal Jun 2021Mitochondrial homeostasis is essential for providing cellular energy, particularly in resource-demanding neurons, defects in which cause neurodegeneration, but the...
Mitochondrial homeostasis is essential for providing cellular energy, particularly in resource-demanding neurons, defects in which cause neurodegeneration, but the function of interferons (IFNs) in regulating neuronal mitochondrial homeostasis is unknown. We found that neuronal IFN-β is indispensable for mitochondrial homeostasis and metabolism, sustaining ATP levels and preventing excessive ROS by controlling mitochondrial fission. IFN-β induces events that are required for mitochondrial fission, phosphorylating STAT5 and upregulating PGAM5, which phosphorylates serine 622 of Drp1. IFN-β signaling then recruits Drp1 to mitochondria, oligomerizes it, and engages INF2 to stabilize mitochondria-endoplasmic reticulum (ER) platforms. This process tethers damaged mitochondria to the ER to separate them via fission. Lack of neuronal IFN-β in the Ifnb model of Parkinson disease (PD) disrupts STAT5-PGAM5-Drp1 signaling, impairing fission and causing large multibranched, damaged mitochondria with insufficient ATP production and excessive oxidative stress to accumulate. In other PD models, IFN-β rescues dopaminergic neuronal cell death and pathology, associated with preserved mitochondrial homeostasis. Thus, IFN-β activates mitochondrial fission in neurons through the pSTAT5/PGAM5/ Drp1 pathway to stabilize mitochondria/ER platforms, constituting an essential neuroprotective mechanism.
Topics: Animals; Cell Line; Cell Line, Tumor; Dynamins; Formins; Interferon-beta; Mice; Mitochondria; Mitochondrial Dynamics; Neurons; Parkinson Disease; Phosphoprotein Phosphatases; STAT5 Transcription Factor
PubMed: 33913175
DOI: 10.15252/embj.2020106868 -
Osteoarthritis and Cartilage Feb 2022To determine the Dynamin-related protein 1 (DRP1) regulation of mitochondrial fission in chondrocytes under pathological conditions, an area which is underexplored in...
OBJECTIVE
To determine the Dynamin-related protein 1 (DRP1) regulation of mitochondrial fission in chondrocytes under pathological conditions, an area which is underexplored in osteoarthritis pathogenesis.
DESIGN
DRP1 protein expression was determined by immunohistochemistry (IHC) or immunofluorescence (IF) staining of cartilage sections. IL-1β-induced DRP1 mRNA expression in chondrocytes was quantified by qPCR and protein expression by immunoblotting. Mitochondrial fragmentation in chondrocytes was visualized by MitoTracker staining or IF staining of mitochondrial marker proteins or by transient expression of mitoDsRed. Mitochondrial reactive oxygen species (ROS) levels were determined by MitoSOX staining. Apoptosis was determined by lactate dehydrogenase (LDH) release assay, Caspase 3/7 activity assay, propidium iodide (PI), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and IF staining of cleaved caspase 3. Cytochrome c release was determined by confocal microscopy. Surgical destabilization of the medial meniscus (DMM) was used to induce osteoarthritis (OA) in mice.
RESULTS
Expression of DRP1 and mitochondrial damage was high in human OA cartilage and in the joints of mice subjected to DMM surgery which also showed increased chondrocytes apoptosis. IL-1β-induced mitochondrial network fragmentation and chondrocyte apoptosis via modulation of DRP1 expression and activity and induce apoptosis via Bax-mediated release of Cytochrome c. Pharmacological inhibition of DRP1 activity by Mdivi-1 blocked IL-1β-induced mitochondrial damage and apoptosis in chondrocytes. Additionally, IL-1β-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) is crucial for DRP1 activation and induction of mitochondrial network fragmentation in chondrocytes as these were blocked by inhibiting ERK1/2 activation.
CONCLUSIONS
These findings demonstrate that ERK1/2 is a critical player in DRP1-mediated induction of mitochondrial fission and apoptosis in IL-1β-stimulated chondrocytes.
Topics: Aged; Animals; Apoptosis; Chondrocytes; Dynamins; Female; Humans; MAP Kinase Signaling System; Male; Mice; Middle Aged; Mitochondrial Dynamics
PubMed: 34767958
DOI: 10.1016/j.joca.2021.11.003 -
Journal of Translational Medicine Jun 2023Inflammation and immune dysfunction with classically activated macrophages(M1) infiltration are important mechanisms in the progression of atherosclerosis (AS)....
BACKGROUND
Inflammation and immune dysfunction with classically activated macrophages(M1) infiltration are important mechanisms in the progression of atherosclerosis (AS). Dynamin-related protein 1 (DRP1)-dependent mitochondrial fission is a novel target for alleviating inflammatory diseases. This study aimed to investigate the effects of DRP1 inhibitor Mdivi-1 on AS.
METHODS
ApoE mice were fed with a high-fat diet supplemented with or without Mdivi-1. RAW264.7 cells were stimulated by ox-LDL, pretreated with or without MCC950, Mito-TEMPO, or Mdivi-1. The burden of plaques and foam cell formation were determined using ORO staining. The blood lipid profles and inflammatory cytokines in serum were detected by commercial kits and ELISA, respectively. The mRNA expression of macrophage polarization markers, activation of NLRP3 and the phosphorylation state of DRP1 were detected. Mitochondrial reactive oxygen species (mito-ROS), mitochondrial staining, ATP level and mitochondrial membrane potential were detected by mito-SOX, MitoTracker, ATP determination kit and JC-1 staining, respectively.
RESULTS
In vivo, Mdivi-1 reduced the plaque areas, M1 polarization, NLRP3 activation and DRP1 phosphorylation at Ser616. In vitro, oxidized low-density lipoprotein (ox-LDL) triggered M1 polarization, NLRP3 activation and abnormal accumulation of mito-ROS. MCC950 and Mito-TEMPO suppressed M1 polarization mediated foam cell formation. Mito-TEMPO significantly inhibited NLRP3 activation. In addition, Mdivi-1 reduced foam cells by inhibiting M1 polarization. The possible mechanisms responsible for the anti-atherosclerotic effects of Mdivi-1 on reducing M1 polarization were associated with suppressing mito-ROS/NLRP3 pathway by inhibiting DRP1 mediated mitochondrial fission. In vitro, similar results were observed by DRP1 knockdown.
CONCLUSION
Inhibition of DRP1-dependent mitochondrial fission by Mdivi-1 alleviated atherogenesis via suppressing mito-ROS/NLRP3-mediated M1 polarization, indicating DRP1-dependent mitochondrial fission as a potential therapeutic target for AS.
Topics: Animals; Mice; Mitochondrial Dynamics; NLR Family, Pyrin Domain-Containing 3 Protein; Reactive Oxygen Species; Atherosclerosis; Dynamins; Furans; Indenes; Adenosine Triphosphate
PubMed: 37386574
DOI: 10.1186/s12967-023-04270-9 -
Nature Neuroscience Oct 2019In neurodegenerative diseases, debris of dead neurons are thought to trigger glia-mediated neuroinflammation, thus increasing neuronal death. Here we show that the...
In neurodegenerative diseases, debris of dead neurons are thought to trigger glia-mediated neuroinflammation, thus increasing neuronal death. Here we show that the expression of neurotoxic proteins associated with these diseases in microglia alone is sufficient to directly trigger death of naive neurons and to propagate neuronal death through activation of naive astrocytes to the A1 state. Injury propagation is mediated, in great part, by the release of fragmented and dysfunctional microglial mitochondria into the neuronal milieu. The amount of damaged mitochondria released from microglia relative to functional mitochondria and the consequent neuronal injury are determined by Fis1-mediated mitochondrial fragmentation within the glial cells. The propagation of the inflammatory response and neuronal cell death by extracellular dysfunctional mitochondria suggests a potential new intervention for neurodegeneration-one that inhibits mitochondrial fragmentation in microglia, thus inhibiting the release of dysfunctional mitochondria into the extracellular milieu of the brain, without affecting the release of healthy neuroprotective mitochondria.
Topics: Animals; Astrocytes; Cell Death; Dynamins; Extracellular Space; Humans; Inflammation; Mice; Mice, Inbred C57BL; Microglia; Mitochondria; Mitochondrial Proteins; Nerve Degeneration; Neurons; Rats; Rats, Sprague-Dawley
PubMed: 31551592
DOI: 10.1038/s41593-019-0486-0 -
Autophagy Dec 2019Mitochondrial dynamics is highly implicated in a plethora of cellular processes including apoptosis and mitophagy. However, little is known about the scope and precise...
Mitochondrial dynamics is highly implicated in a plethora of cellular processes including apoptosis and mitophagy. However, little is known about the scope and precise functions of mitochondrial dynamics proteins for mitochondrial quality control and cellular homeostasis. Whether mitochondrial dynamics proteins serve in cellular processes reliant on mitochondrial fission-fusion is still not fully explored. MIEF1/MiD51 (mitochondrial elongation factor 1) is known to promote mitochondrial fission via the recruitment of GTPase protein DNM1L/DRP1 (dynamin 1 like), but the fundamental understandings of MIEF1 for mitochondrial-dependent cellular processes are largely elusive. Here, we report novel roles of MIEF1 in responding to apoptotic stimuli and mitochondrial damage. Given our result that staurosporine (STS) treatment induced the degradation of MIEF1 via the ubiquitin-proteasome system (UPS), we are motivated to explore the role of MIEF1 in apoptosis. MIEF1 loss triggered the imbalance of BCL2 family members on the mitochondria, consequently initiating the translocation of BAX onto the mitochondria, catalyzing the decrease of mitochondrial membrane potential and promoting the release of DIABLO/SMAC (diablo IAP-binding mitochondrial protein) and CYCS (cytochrome c, somatic). We further demonstrate that MIEF1 deficiency impaired mitochondrial respiration and induced mitochondrial oxidative stress, sensitizing cells to PINK1-PRKN-mediated mitophagy. The recruitment of PRKN to depolarized mitochondria modulated the UPS-dependent degradation of MFN2 (mitofusin 2) and FIS1 (fission, mitochondrial 1) specifically, to further promote mitophagy. Our findings uncover a bridging role of MIEF1 integrating cell death and mitophagy, unlikely dependent on mitochondrial dynamics, implying new insights to mechanisms determining cellular fate.: ActD: actinomycin D; BAX: BCL2 associated X, apoptosis regulator; BAK1: BCL2 antagonist/killer 1; BCL2L1: BCL2 like 1; BMH: 1,6-bismaleimidohexane; CCCP: carbonyl cyanide 3-chlorophenylhydrazone; CHX: cycloheximide; CQ: chloroquine; CYCS: cytochrome c, somatic; DIABLO: diablo IAP-binding mitochondrial protein; DKO: double knockout; DNM1L/DRP1: dynamin 1 like; FIS1: fission, mitochondrial 1; GFP: green fluorescent protein; IP: immunoprecipitation; MFN1: mitofusin 1; MFN2: mitofusin 2; MG132: carbobenzoxy-Leu-Leu-leucinal; MIEF1/MiD51: mitochondrial elongation factor 1; MIEF2/MiD49: mitochondrial elongation factor 2; MOMP: mitochondrial outer membrane permeabilization; MTR: MitoTracker Red; OA: oligomycin plus antimycin A; OCR: oxygen consumption rate; OMM: outer mitochondrial membrane; PARP: poly(ADP-ribose) polymerase; PI: propidium iodide; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; SD: standard deviation; STS: staurosporine; TNF: tumor necrosis factor; UPS: ubiquitin-proteasome system; VDAC1: voltage dependent anion channel 1.
Topics: Apoptosis; Apoptosis Regulatory Proteins; Dynamins; GTP Phosphohydrolases; HEK293 Cells; HeLa Cells; Humans; Membrane Potential, Mitochondrial; Membrane Proteins; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Mitophagy; Peptide Elongation Factors; Proteasome Endopeptidase Complex; Protein Kinases; Reactive Oxygen Species; Receptors, Cytoplasmic and Nuclear; Staurosporine; Ubiquitin-Protein Ligases; Ubiquitination; bcl-2-Associated X Protein; bcl-X Protein
PubMed: 30894073
DOI: 10.1080/15548627.2019.1596494 -
British Journal of Pharmacology Dec 2019Accumulating evidence indicates that mitochondrial dynamics play an important role in the progressive deterioration of dopaminergic neurons. Andrographolide has been...
BACKGROUND AND PURPOSE
Accumulating evidence indicates that mitochondrial dynamics play an important role in the progressive deterioration of dopaminergic neurons. Andrographolide has been found to exert neuroprotective effects in several models of neurological diseases. However, the mechanism of how andrographolide protects neurons in Parkinson's disease (PD) remains not fully understood.
EXPERIMENTAL APPROACH
Behavioural experiments were performed to examine the effect of andrographolide in 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-PD mice. Mitochondrial mass and morphology were visualized using transmission electron microscopy (TEM). SH-SY5Y cells and primary mouse neurons were exposed to rotenone to mimic PD in vitro. Western blotting, co-immunoprecipitation and immunofluorescence were performed. The target protein of andrographolide was identified by biotin-andrographolide pulldown assay as well as drug affinity responsive target stability (DARTS), cellular thermal shift (CETSA), and surface plasmon resonance (SPR) assays.
KEY RESULTS
Andrographolide administration improved behavioural deficits and attenuated loss of dopaminergic neurons in MPTP-exposed mice and reduced cell death induced by rotenone in vitro. An increased mitochondrial mass, and decreased surface area were found in the striatum from MPTP-PD mice, as well as in rotenone-treated primary neurons and SH-SY5Y cells, while andrographolide treatment preserved mitochondrial mass and morphology. Dynamin-related protein 1 (DRP1) was identified as a target protein of andrographolide. Andrographolide bound to DRP1 and inhibited its GTPase activity, thereby preventing excessive mitochondria fission and neuronal damage in PD.
CONCLUSIONS AND IMPLICATIONS
Our findings suggest that andrographolide may protect neurons against rotenone- or MPTP-induced damage in vitro and in vivo through inhibiting mitochondrial fission.
Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Cell Line, Tumor; Cell Survival; Diterpenes; Dynamins; Humans; Mice; Mice, Inbred C57BL; Mitochondria; Mitochondrial Dynamics; Neuroprotective Agents; Parkinson Disease; Surface Plasmon Resonance
PubMed: 31389613
DOI: 10.1111/bph.14823 -
Atherosclerosis Apr 2022Vascular calcification (VC) is an intricate active process, significantly controlled by vascular smooth muscle cells (VSMCs). Mitochondrial dysfunction plays a pivotal...
Irisin alleviates vascular calcification by inhibiting VSMC osteoblastic transformation and mitochondria dysfunction via AMPK/Drp1 signaling pathway in chronic kidney disease.
BACKGROUND AND AIMS
Vascular calcification (VC) is an intricate active process, significantly controlled by vascular smooth muscle cells (VSMCs). Mitochondrial dysfunction plays a pivotal role in VC and VSMCs osteoblastic transformation. We previously reported that decreased levels of Irisin were independently associated with VC in hemodialysis patients. The present study aimed to investigate the role of Irisin in VC, especially in VSMCs osteoblastic transformation and mitochondrial function.
METHODS
In vitro, VSMCs calcification was induced by β-glycerophosphate, while in vivo VC was triggered by adenine and high phosphorus diet. Alizarin red, Von Kossa staining, and calcium and Alp activity were performed to test VC. Western blot and immunohistochemical staining were employed to analyze the expression of proteins associated with VSMCs osteoblastic transformation and AMPK signaling. Mitochondrial membrane potential (MMP) and structures were observed by immunofluorescence staining.
RESULTS
Irisin alleviated VSMCs calcification induced by β-glycerophosphate. Mechanistically, Irisin activated AMPK and downregulated the expression of Drp1, further alleviating mitochondria fission and VSMCs osteoblastic transformation. In vivo, Irisin decreased serum creatinine, urea and phosphorous levels in chronic kidney disease (CKD) mice. Importantly, Irisin treatment postponed CKD-associated VC with the upregulation of α-Sma and p-AMPK expression, and the downregulation of Runx2 and Drp1 expression.
CONCLUSIONS
Our results firstly reveal that Irisin inhibits CKD-associated VC. Irisin suppresses VSMCs osteoblastic transformation and mitochondria dysfunction via AMPK/Drp1 signaling.
Topics: AMP-Activated Protein Kinases; Animals; Cells, Cultured; Dynamins; Fibronectins; Humans; Mice; Mitochondria; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Renal Insufficiency, Chronic; Signal Transduction; Vascular Calcification
PubMed: 35255258
DOI: 10.1016/j.atherosclerosis.2022.02.007 -
Cell Death and Differentiation Oct 2022Cancer cells are known for their ability to adapt variable metabolic programs depending on the availability of specific nutrients. Our previous studies have shown that...
Cancer cells are known for their ability to adapt variable metabolic programs depending on the availability of specific nutrients. Our previous studies have shown that uptake of fatty acids alters cellular metabolic pathways in colon cancer cells to favor fatty acid oxidation. Here, we show that fatty acids activate Drp1 to promote metabolic plasticity in cancer cells. Uptake of fatty acids (FAs) induces mitochondrial fragmentation by promoting ERK-dependent phosphorylation of Drp1 at the S616 site. This increased phosphorylation of Drp1 enhances its dimerization and interaction with Mitochondrial Fission Factor (MFF) at the mitochondria. Consequently, knockdown of Drp1 or MFF attenuates fatty acid-induced mitochondrial fission. In addition, uptake of fatty acids triggers mitophagy via a Drp1- and p62-dependent mechanism to protect mitochondrial integrity. Moreover, results from metabolic profiling analysis reveal that silencing Drp1 disrupts cellular metabolism and blocks fatty acid-induced metabolic reprograming by inhibiting fatty acid utilization. Functionally, knockdown of Drp1 decreases Wnt/β-catenin signaling by preventing fatty acid oxidation-dependent acetylation of β-catenin. As a result, Drp1 depletion inhibits the formation of tumor organoids in vitro and xenograft tumor growth in vivo. Taken together, our study identifies Drp1 as a key mediator that connects mitochondrial dynamics with fatty acid metabolism and cancer cell signaling.
Topics: Colonic Neoplasms; Dynamins; Fatty Acids; Humans; Mitochondrial Dynamics; Mitochondrial Proteins; Phosphorylation; Wnt Signaling Pathway; beta Catenin
PubMed: 35332310
DOI: 10.1038/s41418-022-00974-5 -
Journal of Biochemistry Mar 2020The mitochondrion is an essential organelle for a wide range of cellular processes, including energy production, metabolism, signal transduction and cell death. To... (Review)
Review
The mitochondrion is an essential organelle for a wide range of cellular processes, including energy production, metabolism, signal transduction and cell death. To execute these functions, mitochondria regulate their size, number, morphology and distribution in cells via mitochondrial division and fusion. In addition, mitochondrial division and fusion control the autophagic degradation of dysfunctional mitochondria to maintain a healthy population. Defects in these dynamic membrane processes are linked to many human diseases that include metabolic syndrome, myopathy and neurodegenerative disorders. In the last several years, our fundamental understanding of mitochondrial fusion, division and degradation has been significantly advanced by high resolution structural analyses, protein-lipid biochemistry, super resolution microscopy and in vivo analyses using animal models. Here, we summarize and discuss this exciting recent progress in the mechanism and function of mitochondrial division and fusion.
Topics: Actins; Animals; Dynamins; Endoplasmic Reticulum; GTP Phosphohydrolases; Humans; Lipid Metabolism; Mitochondria; Mitochondrial Dynamics; Mitophagy
PubMed: 31800050
DOI: 10.1093/jb/mvz106