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Nature Reviews. Neuroscience Sep 2022
Topics: Dynamins; Humans
PubMed: 35922543
DOI: 10.1038/s41583-022-00626-0 -
Advanced Science (Weinheim,... Dec 2023Excessive mitochondrial fission following ischemia and hypoxia relies on the formation of contacts between the endoplasmic reticulum and mitochondria (ER-Mito); however,...
Excessive mitochondrial fission following ischemia and hypoxia relies on the formation of contacts between the endoplasmic reticulum and mitochondria (ER-Mito); however, the specific mechanisms behind this process remain unclear. Confocal microscopy and time course recording are used to investigate how ischemia and hypoxia affect the activation of dynamin-related protein 1 (Drp1), a protein central to mitochondrial dynamics, ER-Mito interactions, and the consequences of modifying the expression of Drp1, shroom (Shrm) 4, and inverted formin (INF) 2 on ER-Mito contact establishment. Both Drp1 activation and ER-Mito contact initiation cause excessive mitochondrial fission and dysfunction under ischemic-hypoxic conditions. The activated form of Drp1 aids in ER-Mito contact initiation by recruiting Shrm4 and promoting actin bundling between the ER and mitochondria. This process relies on the structural interplay between INF2 and scattered F-actin on the ER. This study uncovers new roles of cytoplasmic Drp1, providing valuable insights for devising strategies to manage mitochondrial imbalances in the context of ischemic-hypoxic injury.
Topics: Humans; Actins; Dynamins; Mitochondria; Endoplasmic Reticulum; Ischemia; Hypoxia
PubMed: 37909346
DOI: 10.1002/advs.202304885 -
Journal of Translational Medicine Oct 2023Extracellular matrix stiffness is emerging as a crucial mechanical cue that drives the progression of various diseases, such as cancer, fibrosis, and inflammation. The...
BACKGROUND
Extracellular matrix stiffness is emerging as a crucial mechanical cue that drives the progression of various diseases, such as cancer, fibrosis, and inflammation. The matrix stiffness of the nucleus pulposus (NP) tissues increase gradually during intervertebral disc degeneration (IDD), while the mechanism through which NP cells sense and react to matrix stiffness remains unclear. In addition, mitochondrial dynamics play a key role in various cellular functions. An in-depth investigation of the pathogenesis of IDD can provide new insights for the development of effective therapies. In this study, we aim to investigate the effects of matrix stiffness on mitochondrial dynamics in IDD.
METHODS
To build the gradient stiffness model, NP cells were cultured on polystyrene plates with different stiffness. Western blot analysis, and immunofluorescence staining were used to detect the expression of mitochondrial dynamics-related proteins. Flow cytometry was used to detect the mitochondrial membrane potential and intracellular Ca levels. Apoptosis related proteins, ROS level, and TUNEL staining were performed to assess the effect of substrate stiffness on NP cells.
RESULTS
Stiff substrate increased phosphorylation of dynamin-related protein 1 (Drp1) at Ser616 by activating extracellular signal-regulated kinase 1/2 (ERK1/2) pathway, which promoted mitochondrial fission and apoptosis in NP cells. Furthermore, Piezo1 activation was involved in the regulation of the post-translational modifications of Drp1 and mitochondrial fission caused by matrix stiffness. Inhibition of Piezo1 and ERK1/2 can effectively reduce stiffness-induced ROS elevation and apoptosis in NP cells.
CONCLUSIONS
Our results revealed that stiff substrate causes Piezo1 activation and Ca influx, results in ERK1/2 activation and phosphorylation of Drp1 at S616, and finally leads to mitochondrial fission and apoptosis in NP cells. These findings reveal a new mechanism of mechanotransduction in NP cells, providing novel insights into the development of therapies for treating IDD.
Topics: Humans; Intervertebral Disc Degeneration; Mitochondrial Dynamics; Mechanotransduction, Cellular; Reactive Oxygen Species; Apoptosis; Dynamins; Intervertebral Disc
PubMed: 37817199
DOI: 10.1186/s12967-023-04590-w -
Current Opinion in Cell Biology Apr 2023Dynamin, a 100-kDa GTPase, is one of the most-characterized membrane fission machineries catalyzing vesicle release from plasma membrane during endocytosis. The human... (Review)
Review
Dynamin, a 100-kDa GTPase, is one of the most-characterized membrane fission machineries catalyzing vesicle release from plasma membrane during endocytosis. The human genome encodes three dynamins: DNM1, DNM2 and DNM3, with high amino acid similarity but distinct expression patterns. Ever since the discoveries of dynamin mutations associated with human diseases in 2005, dynamin has become a paradigm for studying pathogenic mechanisms of mutant proteins from the aspects of structural biology, cell biology, model organisms as well as therapeutic strategy development. Here, we review the diseases and pathogenic mechanisms caused by mutations of DNM1 and DNM2, focusing on the activity requirement and regulation of dynamins in different tissues.
Topics: Humans; Dynamin II; Dynamins; Mutation; GTP Phosphohydrolases; Endocytosis
PubMed: 37230036
DOI: 10.1016/j.ceb.2023.102174 -
Nature Communications Mar 2022Mitochondrial fission is critically important for controlling mitochondrial morphology, function, quality and transport. Drp1 is the master regulator driving...
Mitochondrial fission is critically important for controlling mitochondrial morphology, function, quality and transport. Drp1 is the master regulator driving mitochondrial fission, but exactly how Drp1 is regulated remains unclear. Here, we identified Drosophila Clueless and its mammalian orthologue CLUH as key regulators of Drp1. As with loss of drp1, depletion of clueless or CLUH results in mitochondrial elongation, while as with drp1 overexpression, clueless or CLUH overexpression leads to mitochondrial fragmentation. Importantly, drp1 overexpression rescues adult lethality, tissue disintegration and mitochondrial defects of clueless null mutants in Drosophila. Mechanistically, Clueless and CLUH promote recruitment of Drp1 to mitochondria from the cytosol. This involves CLUH binding to mRNAs encoding Drp1 receptors MiD49 and Mff, and regulation of their translation. Our findings identify a crucial role of Clueless and CLUH in controlling mitochondrial fission through regulation of Drp1.
Topics: Animals; Cytoskeletal Proteins; Drosophila; Dynamins; GTP-Binding Proteins; Mammals; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Peptide Elongation Factors
PubMed: 35332133
DOI: 10.1038/s41467-022-29071-4 -
The Journal of Biological Chemistry May 2023Autophagy is a key process in eukaryotes to maintain cellular homeostasis by delivering cellular components to lysosomes/vacuoles for degradation and reuse of the...
Autophagy is a key process in eukaryotes to maintain cellular homeostasis by delivering cellular components to lysosomes/vacuoles for degradation and reuse of the resulting metabolites. Membrane rearrangements and trafficking events are mediated by the core machinery of autophagy-related (Atg) proteins, which carry out a variety of functions. How Atg9, a lipid scramblase and the only conserved transmembrane protein within this core Atg machinery, is trafficked during autophagy remained largely unclear. Here, we addressed this question in yeast Saccharomyces cerevisiae and found that retromer complex and dynamin Vps1 mutants alter Atg9 subcellular distribution and severely impair the autophagic flux by affecting two separate autophagy steps. We provide evidence that Vps1 interacts with Atg9 at Atg9 reservoirs. In the absence of Vps1, Atg9 fails to reach the sites of autophagosome formation, and this results in an autophagy defect. The function of Vps1 in autophagy requires its GTPase activity. Moreover, Vps1 point mutants associated with human diseases such as microcytic anemia and Charcot-Marie-Tooth are unable to sustain autophagy and affect Atg9 trafficking. Together, our data provide novel insights on the role of dynamins in Atg9 trafficking and suggest that a defect in this autophagy step could contribute to severe human pathologies.
Topics: Humans; Autophagosomes; Saccharomyces cerevisiae Proteins; Saccharomyces cerevisiae; Dynamins; Vacuoles; Autophagy; Autophagy-Related Proteins; Protein Transport; GTP-Binding Proteins; Vesicular Transport Proteins; Membrane Proteins
PubMed: 37060997
DOI: 10.1016/j.jbc.2023.104712 -
Biomedicine & Pharmacotherapy =... Sep 2023Mitochondrial dysfunction, especially in terms of mitochondrial dynamics, has been reported to be closely associated with neuronal outcomes and neurological impairment... (Review)
Review
Mitochondrial dysfunction, especially in terms of mitochondrial dynamics, has been reported to be closely associated with neuronal outcomes and neurological impairment in cerebral ischemia/hypoxia injury. Dynamin-related protein 1 (Drp1) is a cytoplasmic GTPase that mediates mitochondrial fission and participates in neuronal cell death, calcium signaling, and oxidative stress. The neuroprotective role of Drp1 inhibition has been confirmed in several central nervous system disease models, demonstrating that targeting Drp1 may shed light on novel approaches for the treatment of cerebral ischemia/hypoxia injury. In this review, we aimed to highlight the roles of Drp1 in programmed cell death, oxidative stress, mitophagy, and mitochondrial function to provide a better understanding of mitochondrial disturbances in cerebral ischemia/hypoxia injury, and we also summarize the advances in novel chemical compounds targeting Drp1 to provide new insights into potential therapies for cerebral ischemia/hypoxia injury.
Topics: Humans; Brain Ischemia; Dynamins; Hypoxia; Mitochondria; Neurons; Animals
PubMed: 37516018
DOI: 10.1016/j.biopha.2023.115247 -
EMBO Reports Jun 2023Mycobacterium tuberculosis (Mtb) secretes extracellular vesicles (EVs) containing a variety of proteins, lipoproteins, and lipoglycans. While emerging evidence suggests...
Mycobacterium tuberculosis (Mtb) secretes extracellular vesicles (EVs) containing a variety of proteins, lipoproteins, and lipoglycans. While emerging evidence suggests that EVs contribute to tuberculosis pathogenesis, the factors and molecular mechanisms involved in mycobacterial EV production have not been identified. In this study, we use a genetic approach to identify Mtb proteins that mediate vesicle release in response to iron limitation and antibiotic exposure. We uncover a critical role for the isoniazid-induced, dynamin-like proteins, IniA and IniC, in mycobacterial EV biogenesis. Further characterization of a Mtb iniA mutant shows that the production of EVs enables intracellular Mtb to export bacterial components into the extracellular environment to communicate with host cells and potentially modulate the immune response. The findings advance our understanding of the biogenesis and functions of mycobacterial EVs and provide an avenue for targeting vesicle production in vivo.
Topics: Humans; Mycobacterium tuberculosis; Tuberculosis; Extracellular Vesicles; Isoniazid; Dynamins
PubMed: 37079766
DOI: 10.15252/embr.202255593 -
Biochemical Pharmacology Nov 2023We studied the effect of cotadutide, a dual agonist glucagon-like peptide 1 (GLP1)/Glucagon, on interscapular brown adipose tissue (iBAT) remodeling and thermogenesis of...
We studied the effect of cotadutide, a dual agonist glucagon-like peptide 1 (GLP1)/Glucagon, on interscapular brown adipose tissue (iBAT) remodeling and thermogenesis of obese mice. Twelve-week-old male C57BL/6 mice were fed a control diet (C group, n = 20) or a high-fat diet (HF group, n = 20) for ten weeks. Then, animals were redivided, adding cotadutide treatment: C, CC, HF, and HFC for four additional weeks. The multilocular brown adipocyte structure showed fat conversion (whitening), hypertrophy, and structural disarray in the HF group, which was reverted in cotadutide-treated animals. Cotadutide enhances the body temperature, thermogenesis, and sympathetic innervation (peroxisome proliferator-activated receptor-α, β3 adrenergic receptor, interleukin 6, and uncoupled protein 1), reduces pro-inflammatory markers (disintegrin and metallopeptidase domain, morphogenetic protein 8a, and neuregulin 4), and improves angiogenesis (vascular endothelial growth factor A, and perlecan). In addition, cotadutide enhances lipolysis (perilipin and cell death-inducing DNA fragmentation factor α), mitochondrial biogenesis (nuclear respiratory factor 1, transcription factor A mitochondrial, mitochondrial dynamin-like GTPase, and peroxisome proliferator-activated receptor gamma coactivator 1α), and mitochondrial fusion/fission (dynamin-related protein 1, mitochondrial fission protein 1, and parkin RBR E3 ubiquitin protein ligase). Cotadutide reduces endoplasmic reticulum stress (activating transcription factor 4, C/EBP homologous protein, and growth arrest and DNA-damage inducible), and extracellular matrix markers (lysyl oxidase, collagen type I α1, collagen type VI α3, matrix metallopeptidases 2 and 9, and hyaluronan synthases 1 and 2). In conclusion, the experimental evidence is compelling in demonstrating cotadutide's thermogenic effect on obese mice's iBAT, contributing to unraveling its action mechanisms and the possible translational benefits.
Topics: Mice; Animals; Male; Adipose Tissue, Brown; Mice, Obese; Vascular Endothelial Growth Factor A; Mice, Inbred C57BL; Obesity; Adipocytes, Brown; Diet, High-Fat; Thermogenesis; Dynamins; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
PubMed: 37832793
DOI: 10.1016/j.bcp.2023.115852 -
Cells Jul 2023Mitochondria, which generate ATP through aerobic respiration, also have important noncanonical functions. Mitochondria are dynamic organelles, that engage in fission... (Review)
Review
Mitochondria, which generate ATP through aerobic respiration, also have important noncanonical functions. Mitochondria are dynamic organelles, that engage in fission (division), fusion (joining) and translocation. They also regulate intracellular calcium homeostasis, serve as oxygen-sensors, regulate inflammation, participate in cellular and organellar quality control and regulate the cell cycle. Mitochondrial fission is mediated by the large GTPase, dynamin-related protein 1 (Drp1) which, when activated, translocates to the outer mitochondrial membrane (OMM) where it interacts with binding proteins (Fis1, MFF, MiD49 and MiD51). At a site demarcated by the endoplasmic reticulum, fission proteins create a macromolecular ring that divides the organelle. The functional consequence of fission is contextual. Physiological fission in healthy, nonproliferating cells mediates organellar quality control, eliminating dysfunctional portions of the mitochondria via mitophagy. Pathological fission in somatic cells generates reactive oxygen species and triggers cell death. In dividing cells, Drp1-mediated mitotic fission is critical to cell cycle progression, ensuring that daughter cells receive equitable distribution of mitochondria. Mitochondrial fusion is regulated by the large GTPases mitofusin-1 (Mfn1) and mitofusin-2 (Mfn2), which fuse the OMM, and optic atrophy 1 (OPA-1), which fuses the inner mitochondrial membrane. Mitochondrial fusion mediates complementation, an important mitochondrial quality control mechanism. Fusion also favors oxidative metabolism, intracellular calcium homeostasis and inhibits cell proliferation. Mitochondrial lipids, cardiolipin and phosphatidic acid, also regulate fission and fusion, respectively. Here we review the role of mitochondrial dynamics in health and disease and discuss emerging concepts in the field, such as the role of central versus peripheral fission and the potential role of dynamin 2 (DNM2) as a fission mediator. In hyperproliferative diseases, such as pulmonary arterial hypertension and cancer, Drp1 and its binding partners are upregulated and activated, positing mitochondrial fission as an emerging therapeutic target.
Topics: Humans; Mitochondrial Dynamics; Pulmonary Arterial Hypertension; Calcium; Dynamins; GTP Phosphohydrolases; Cell Cycle; Neoplasms
PubMed: 37508561
DOI: 10.3390/cells12141897