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Arthritis Research & Therapy Jul 2023Gouty arthritis is the most frequently diagnosed inflammatory arthritis worldwide. Dynamin-related protein 1 (Drp1), a regulator of mitochondrial fission, contributes to...
BACKGROUND
Gouty arthritis is the most frequently diagnosed inflammatory arthritis worldwide. Dynamin-related protein 1 (Drp1), a regulator of mitochondrial fission, contributes to various inflammatory disorders via activating NLRP3 inflammasome. However, the biological role of Drp1 in gouty arthritis remains undefined.
METHODS
A mouse model of monosodium urate (MSU)-induced gouty arthritis and MSU-stimulated macrophages were established as in vivo and in vitro models, respectively. Histological changes were assessed by H&E and IHC analysis. RT-qPCR and western blot were used to detect the expression of Drp1 and the key molecules in joint tissues and macrophages. Cytokine secretion was measured by ELISA assay, and antioxidant enzymes activities and LDH release were monitored using commercial kits. Mitochondrial structure and functions were assessed by transmission electron microscopy (TEM) and MitoSOX staining. Co-IP and GST pull-down assay were used to detect the direct interaction between USP16 and Drp1, as well as the ubiquitination of Drp1.
RESULTS
Drp1 was elevated in MSU-induced gouty arthritis model, and it induced gouty arthritis via NF-κB pathway and NLRP3 inflammasome activation. In addition, Drp1 activated NF-κB/NLRP3 signaling via modulating mitochondrial fission. Mechanistically, USP16 mediated deubiquitination and stabilization of Drp1 through its direct interaction with Drp1. Functional studies further showed that USP16 was highly expressed in MSU-stimulated macrophages and induced gouty arthritis via Drp1-dependent NLRP3 inflammasome activation.
CONCLUSION
Deubiquitinase USP16 induced gouty arthritis via Drp1-dependent mitochondrial fission and NF-κB/NLRP3 signaling.
Topics: Animals; Mice; Arthritis, Gouty; NF-kappa B; Inflammasomes; Mitochondrial Dynamics; NLR Family, Pyrin Domain-Containing 3 Protein; Dynamins; Deubiquitinating Enzymes
PubMed: 37488647
DOI: 10.1186/s13075-023-03095-7 -
The Journal of Cell Biology Dec 2023Live super-resolution microscopy has allowed for new insights into recently identified mitochondria-lysosome contact sites, which mediate crosstalk between mitochondria...
Live super-resolution microscopy has allowed for new insights into recently identified mitochondria-lysosome contact sites, which mediate crosstalk between mitochondria and lysosomes, including co-regulation of Rab7 GTP hydrolysis and Drp1 GTP hydrolysis. Here, we highlight recent findings and future perspectives on this dynamic pathway and its roles in health and disease.
Topics: Guanosine Triphosphate; Lysosomes; Microscopy; Mitochondria; Mitochondrial Membranes; rab7 GTP-Binding Proteins; Dynamins
PubMed: 37917024
DOI: 10.1083/jcb.202305032 -
International Journal of Molecular... Nov 2022Mitochondria have many forms and can change their shape through fusion and fission of the outer and inner membranes, called "mitochondrial dynamics". Mitochondrial outer... (Review)
Review
Mitochondria have many forms and can change their shape through fusion and fission of the outer and inner membranes, called "mitochondrial dynamics". Mitochondrial outer membrane proteins, such as mitochondrial fission protein 1 (FIS1), mitochondrial fission factor (MFF), mitochondrial 98 dynamics proteins of 49 kDa (MiD49), and mitochondrial dynamics proteins of 51 kDa (MiD51), can aggregate at the outer mitochondrial membrane and thus attract Dynamin-related protein 1 (DRP1) from the cytoplasm to the outer mitochondrial membrane, where DRP1 can perform a scissor-like function to cut a complete mitochondrion into two separate mitochondria. Other organelles can promote mitochondrial fission alongside mitochondria. FIS1 plays an important role in mitochondrial-lysosomal contacts, differentiating itself from other mitochondrial-fission-associated proteins. The contact between the two can also induce asymmetric mitochondrial fission. The kidney is a mitochondria-rich organ, requiring large amounts of mitochondria to produce energy for blood circulation and waste elimination. Pathological increases in mitochondrial fission can lead to kidney damage that can be ameliorated by suppressing their excessive fission. This article reviews the current knowledge on the key role of mitochondrial-fission-associated proteins in the pathogenesis of kidney injury and the role of their various post-translational modifications in activation or degradation of fission-associated proteins and targeted drug therapy.
Topics: Humans; Mitochondrial Dynamics; Mitochondrial Proteins; Peptide Elongation Factors; Dynamins; Lysosomes; Kidney Diseases
PubMed: 36499050
DOI: 10.3390/ijms232314725 -
PloS One 2021Current chemotherapy for treatment of pediatric acute leukemia, although generally successful, is still a matter of concern due to treatment resistance, relapses and...
Current chemotherapy for treatment of pediatric acute leukemia, although generally successful, is still a matter of concern due to treatment resistance, relapses and life-long side effects for a subset of patients. Inhibition of dynamin, a GTPase involved in clathrin-mediated endocytosis and regulation of the cell cycle, has been proposed as a potential anti-cancer regimen, but the effects of dynamin inhibition on leukemia cells has not been extensively addressed. Here we adopted single cell and whole-population analysis by flow cytometry and live imaging, to assess the effect of dynamin inhibition (Dynasore, Dyngo-4a, MitMAB) on pediatric acute leukemia cell lines (CCRF-CEM and THP-1), human bone marrow biopsies from patients diagnosed with acute lymphoblastic leukemia (ALL), as well as in a model of lymphoma (EL4)-induced tumor growth in mice. All inhibitors suppressed proliferation and induced pronounced caspase-dependent apoptotic cell death in CCRF-CEM and THP-1 cell lines. However, the inhibitors showed no effect on bone marrow biopsies, and did not prevent EL4-induced tumor formation in mice. We conclude that dynamin inhibition affects highly proliferating human leukemia cells. These findings form a basis for evaluation of the potential, and constraints, of employing dynamin inhibition in treatment strategies against leukemia and other malignancies.
Topics: Animals; Apoptosis; Bone Marrow Cells; Caspases; Cell Cycle; Cell Death; Cell Line, Tumor; Child; Dynamins; Endocytosis; Flow Cytometry; Heterografts; Humans; Mice; Pediatrics; Precursor Cell Lymphoblastic Leukemia-Lymphoma
PubMed: 34492077
DOI: 10.1371/journal.pone.0256708 -
CNS Neuroscience & Therapeutics Nov 2023Emerging evidence suggests that mitochondrial dysfunction plays a crucial role in the pathogenesis of postoperative delayed neurocognitive recovery (dNCR). Mitochondria...
INTRODUCTION
Emerging evidence suggests that mitochondrial dysfunction plays a crucial role in the pathogenesis of postoperative delayed neurocognitive recovery (dNCR). Mitochondria exist in a dynamic equilibrium that involves fission and fusion to regulate morphology and maintains normal cell function via the removal of damaged mitochondria through mitophagy. Nonetheless, the relationship between mitochondrial morphology and mitophagy, and how they influence mitochondrial function in the development of postoperative dNCR, remains poorly understood. Here, we observed morphological alterations of mitochondria and mitophagy activity in hippocampal neurons and assessed the involvement of their interaction in dNCR following general anesthesia and surgical stress in aged rats.
METHODS
Firstly, we evaluated the spatial learning and memory ability of the aged rats after anesthesia/surgery. Hippocampal mitochondrial function and mitochondrial morphology were detected. Afterwards, mitochondrial fission was inhibited by Mdivi-1 and siDrp1 in vivo and in vitro separately. We then detected mitophagy and mitochondrial function. Finally, we used rapamycin to activate mitophagy and observed mitochondrial morphology and mitochondrial function.
RESULTS
Surgery impaired hippocampal-dependent spatial learning and memory ability and caused mitochondrial dysfunction. It also increased mitochondrial fission and inhibited mitophagy in hippocampal neurons. Mdivi-1 improved mitophagy and learning and memory ability of aged rats by inhibiting mitochondrial fission. Knocking down Drp1 by siDrp1 also improved mitophagy and mitochondrial function. Meanwhile, rapamycin inhibited excessive mitochondrial fission and improved mitochondrial function.
CONCLUSION
Surgery simultaneously increases mitochondrial fission and inhibits mitophagy activity. Mechanistically, mitochondrial fission/fusion and mitophagy activity interact reciprocally with each other and are both involved in postoperative dNCR. These mitochondrial events after surgical stress may provide novel targets and modalities for therapeutic intervention in postoperative dNCR.
Topics: Rats; Animals; Mitophagy; Dynamins; Mitochondrial Dynamics; Sirolimus
PubMed: 37208948
DOI: 10.1111/cns.14261 -
Cell Reports Apr 2021During mitochondrial fission, key molecular and cellular factors assemble on the outer mitochondrial membrane, where they coordinate to generate constriction....
During mitochondrial fission, key molecular and cellular factors assemble on the outer mitochondrial membrane, where they coordinate to generate constriction. Constriction sites can eventually divide or reverse upon disassembly of the machinery. However, a role for membrane tension in mitochondrial fission, although speculated, has remained undefined. We capture the dynamics of constricting mitochondria in mammalian cells using live-cell structured illumination microscopy (SIM). By analyzing the diameters of tubules that emerge from mitochondria and implementing a fluorescence lifetime-based mitochondrial membrane tension sensor, we discover that mitochondria are indeed under tension. Under perturbations that reduce mitochondrial tension, constrictions initiate at the same rate, but are less likely to divide. We propose a model based on our estimates of mitochondrial membrane tension and bending energy in living cells which accounts for the observed probability distribution for mitochondrial constrictions to divide.
Topics: Animals; Biomechanical Phenomena; COS Cells; Chlorocebus aethiops; Cytoskeleton; Dynamins; Electron Transport Complex IV; Gene Expression; Genes, Reporter; Green Fluorescent Proteins; Humans; Luminescent Proteins; Mitochondria; Mitochondrial Dynamics; Mitochondrial Membranes; Surface Tension; Transfection; Transgenes; Red Fluorescent Protein
PubMed: 33852852
DOI: 10.1016/j.celrep.2021.108947 -
Nature Communications Jun 2022Membrane budding entails forces to transform flat membrane into vesicles essential for cell survival. Accumulated studies have identified coat-proteins (e.g., clathrin)...
Membrane budding entails forces to transform flat membrane into vesicles essential for cell survival. Accumulated studies have identified coat-proteins (e.g., clathrin) as potential budding factors. However, forces mediating many non-coated membrane buddings remain unclear. By visualizing proteins in mediating endocytic budding in live neuroendocrine cells, performing in vitro protein reconstitution and physical modeling, we discovered how non-coated-membrane budding is mediated: actin filaments and dynamin generate a pulling force transforming flat membrane into Λ-shape; subsequently, dynamin helices surround and constrict Λ-profile's base, transforming Λ- to Ω-profile, and then constrict Ω-profile's pore, converting Ω-profiles to vesicles. These mechanisms control budding speed, vesicle size and number, generating diverse endocytic modes differing in these parameters. Their impact is widespread beyond secretory cells, as the unexpectedly powerful functions of dynamin and actin, previously thought to mediate fission and overcome tension, respectively, may contribute to many dynamin/actin-dependent non-coated-membrane buddings, coated-membrane buddings, and other membrane remodeling processes.
Topics: Actins; Cell Membrane; Clathrin; Coated Pits, Cell-Membrane; Dynamins; Endocytosis
PubMed: 35760780
DOI: 10.1038/s41467-022-31286-4 -
Medical Science Monitor : International... Jun 2020BACKGROUND The classical dynamin family consists of dynamin 1, 2, and 3, which have different expression levels in different tissues to regulate cell membrane fission...
BACKGROUND The classical dynamin family consists of dynamin 1, 2, and 3, which have different expression levels in different tissues to regulate cell membrane fission and endocytosis. Recent studies have reported increased expression of dynamins in human cancer, but their expression in hepatocellular carcinoma (HCC) remains to be determined. This study aimed to investigate the expression of dynamin 1, 2, and 3 in tissue sections of human HCC using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. MATERIAL AND METHODS The expression of dynamin 1, 2, and 3 were investigated in 192 cases of HCC and 14 paired samples of HCC and adjacent normal liver tissue by qRT-PCR and immunohistochemistry. The clinical significance of dynamin 1, 2, and 3 were determined by correlating their expression levels with patient clinicopathological factors and survival rates. Independent prognostic factors were determined using the Cox regression hazard model. RESULTS In tissue samples from 192 patients with HCC, the expression of dynamin 1, 2, and 3 were upregulated in 41.15%, 29.69%, and 8.33% of cases, respectively. Dynamin 1 had a significantly increased mRNA expression level in HCC compared with adjacent normal liver tissues and was significantly correlated with alpha fetoprotein (AFP) levels, T stage, and TNM stage. Only dynamin 1 expression was correlated with the reduced overall survival (OS), and was identified as an independent prognostic biomarker of human HCC. CONCLUSIONS Upregulation of dynamin 1 at the protein and mRNA level was an independent prognostic biomarker of reduced OS in patients with HCC.
Topics: Adult; Carcinoma, Hepatocellular; Cell Line, Tumor; Dynamins; Female; Gene Expression; Humans; Immunohistochemistry; Kaplan-Meier Estimate; Liver Neoplasms; Male; Middle Aged; Neoplasm Staging; Prognosis; Proportional Hazards Models; Transcriptome; alpha-Fetoproteins
PubMed: 32573516
DOI: 10.12659/MSM.923359 -
Journal of Cell Science Feb 2023Mitochondria and peroxisomes are dynamic signaling organelles that constantly undergo fission, driven by the large GTPase dynamin-related protein 1 (DRP1; encoded by...
Mitochondria and peroxisomes are dynamic signaling organelles that constantly undergo fission, driven by the large GTPase dynamin-related protein 1 (DRP1; encoded by DNM1L). Patients with de novo heterozygous missense mutations in DNM1L present with encephalopathy due to defective mitochondrial and peroxisomal fission (EMPF1) - a devastating neurodevelopmental disease with no effective treatment. To interrogate the mechanisms by which DRP1 mutations cause cellular dysfunction, we used human-derived fibroblasts from patients who present with EMPF1. In addition to elongated mitochondrial morphology and lack of fission, patient cells display lower coupling efficiency, increased proton leak and upregulation of glycolysis. Mitochondrial hyperfusion also results in aberrant cristae structure and hyperpolarized mitochondrial membrane potential. Peroxisomes show a severely elongated morphology in patient cells, which is associated with reduced respiration when cells are reliant on fatty acid oxidation. Metabolomic analyses revealed impaired methionine cycle and synthesis of pyrimidine nucleotides. Our study provides insight into the role of mitochondrial dynamics in cristae maintenance and the metabolic capacity of the cell, as well as the disease mechanism underlying EMPF1.
Topics: Humans; Membrane Potential, Mitochondrial; Dynamins; Brain Diseases; GTP Phosphohydrolases; Mutation; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins
PubMed: 36763487
DOI: 10.1242/jcs.260370 -
Journal of Nanobiotechnology May 2024Cartilaginous endplate (CEP) degeneration, which is an important contributor to intervertebral disc degeneration (IVDD), is characterized by chondrocyte death....
BACKGROUND
Cartilaginous endplate (CEP) degeneration, which is an important contributor to intervertebral disc degeneration (IVDD), is characterized by chondrocyte death. Accumulating evidence has revealed that dynamin-related protein 1 (Drp1)-mediated mitochondrial fission and dysfunction lead to apoptosis during CEP degeneration and IVDD. Exosomes are promising agents for the treatment of many diseases, including osteoporosis, osteosarcoma, osteoarthritis and IVDD. Despite their major success in drug delivery, the full potential of exosomes remains untapped.
MATERIALS AND METHODS
In vitro and in vivo models of CEP degeneration were established by using lipopolysaccharide (LPS). We designed genetically engineered exosomes (CAP-Nrf2-Exos) expressing chondrocyte-affinity peptide (CAP) on the surface and carrying the antioxidant transcription factor nuclear factor E2-related factor 2 (Nrf2). The affinity between CAP-Nrf2-Exos and CEP was evaluated by in vitro internalization assays and in vivo imaging assays. qRT‒PCR, Western blotting and immunofluorescence assays were performed to examine the expression level of Nrf2 and the subcellular localization of Nrf2 and Drp1. Mitochondrial function was measured by the JC-1 probe and MitoSOX Red. Mitochondrial morphology was visualized by MitoTracker staining and transmission electron microscopy (TEM). After subendplate injection of the engineered exosomes, the degree of CEP degeneration and IVDD was validated radiologically and histologically.
RESULTS
We found that the cargo delivery efficiency of exosomes after cargo packaging was increased by surface modification. CAP-Nrf2-Exos facilitated chondrocyte-targeted delivery of Nrf2 and activated the endogenous antioxidant defence system in CEP cells. The engineered exosomes inhibited Drp1 S616 phosphorylation and mitochondrial translocation, thereby preventing mitochondrial fragmentation and dysfunction. LPS-induced CEP cell apoptosis was alleviated by CAP-Nrf2-Exo treatment. In a rat model of CEP degeneration, the engineered exosomes successfully attenuated CEP degeneration and IVDD and exhibited better repair capacity than natural exosomes.
CONCLUSION
Collectively, our findings showed that exosome-mediated chondrocyte-targeted delivery of Nrf2 was an effective strategy for treating CEP degeneration.
Topics: Animals; Male; Rats; Apoptosis; Cartilage; Chondrocytes; Drug Delivery Systems; Dynamins; Exosomes; Intervertebral Disc Degeneration; Mitochondria; Mitochondrial Dynamics; NF-E2-Related Factor 2; Rats, Sprague-Dawley
PubMed: 38790015
DOI: 10.1186/s12951-024-02517-1