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Genes & Genomics Jul 2024The apoptosis-resistant pulmonary arterial endothelial cells (PAECs) are known to be major players in the pulmonary remodeling of pulmonary arterial hypertension (PAH)...
STAT3 phosphorylation at Tyr705 affects DRP1 (dynamin-related protein 1) controlled-mitochondrial fission during the development of apoptotic-resistance in pulmonary arterial endothelial cells.
BACKGROUND
The apoptosis-resistant pulmonary arterial endothelial cells (PAECs) are known to be major players in the pulmonary remodeling of pulmonary arterial hypertension (PAH) and exhibit an abnormal metabolic profile with mitochondrial dysfunction. Mitochondrial fission has been shown to regulate the apoptosis of several cell types, but this is largely unexplored in the PAECs.
OBJECTIVE
The roles of mitochondrial fission control by Dynamin related protein-1 (DRP1) in the development of PAECs apoptosis suppression were investigated in present study and the potential mechanisms behind this were furtherly explored.
METHODS
The mitochondrial morphology was investigated in PAECs from PAH rats with the pulmonary plexiform lesions, and the relations of it with DRP1 expression and apoptosis were furtherly identified in apoptosis-resistant PAECs induced by hypoxia. PAECs were isolated from rats with severe PAH and from normal subjects, the apoptotic-resistant PAECs were induced by hypoxia. DRP1 gene knockdown was achieved via DRP1-siRNA, DRP1 and STAT3 phosphorylation were blocked using its inhibitors, respectively. Apoptosis was analyzed by flow cytometry, and mitochondrial morphology was investigated by transmission electron microscope and confocal microscopy.
RESULTS
The PAECs isolated from PAH rats with the pulmonary plexiform-like lesions and displayed lower apoptotic rate with increased DRP1 expression and mitochondrial fragmentation. In addition, similar observations were achieved in apoptosis-resistant PAECs induced by hypoxia. Targeting DRP1 using siRNA and pharmacologic blockade prevented the mitochondrial fission and subsequent apoptotic resistance in PAECs under hypoxia. Mechanistically, STAT3 phosphorylation at Tyr705 was shown to be activated in both PAH and hypoxia-treated PAECs, leading to the regulation of DRP1 expression. Of importance, targeting STAT3Tyr705 phosphorylation prevented DRP1 disruption on apoptosis in PAECs under hypoxia.
CONCLUSIONS
These data indicated that STAT3 phosphorylation at Tyr705 impacted DRP1-controlled mitochondrial fission during the development of apoptosis-resistance in PAECs, suggesting mitochondrial dynamics may represent a therapeutic target for PAH.
Topics: Animals; Dynamins; Mitochondrial Dynamics; Apoptosis; Rats; STAT3 Transcription Factor; Endothelial Cells; Phosphorylation; Pulmonary Artery; Rats, Sprague-Dawley; Male; Mitochondria; Cells, Cultured; Pulmonary Arterial Hypertension; Hypertension, Pulmonary
PubMed: 38733520
DOI: 10.1007/s13258-024-01522-w -
Life Science Alliance Jul 2024Neural stem cells (NSCs) reside in discrete regions of the adult mammalian brain where they can differentiate into neurons, astrocytes, and oligodendrocytes. Several...
Neural stem cells (NSCs) reside in discrete regions of the adult mammalian brain where they can differentiate into neurons, astrocytes, and oligodendrocytes. Several studies suggest that mitochondria have a major role in regulating NSC fate. Here, we evaluated mitochondrial properties throughout NSC differentiation and in lineage-specific cells. For this, we used the neurosphere assay model to isolate, expand, and differentiate mouse subventricular zone postnatal NSCs. We found that the levels of proteins involved in mitochondrial fusion (Mitofusin [Mfn] 1 and Mfn 2) increased, whereas proteins involved in fission (dynamin-related protein 1 [DRP1]) decreased along differentiation. Importantly, changes in mitochondrial dynamics correlated with distinct patterns of mitochondrial morphology in each lineage. Particularly, we found that the number of branched and unbranched mitochondria increased during astroglial and neuronal differentiation, whereas the area occupied by mitochondrial structures significantly reduced with oligodendrocyte maturation. In addition, comparing the three lineages, neurons revealed to be the most energetically flexible, whereas astrocytes presented the highest ATP content. Our work identified putative mitochondrial targets to enhance lineage-directed differentiation of mouse subventricular zone-derived NSCs.
Topics: Animals; Neural Stem Cells; Mitochondria; Mice; Cell Differentiation; Cell Lineage; Astrocytes; Mitochondrial Dynamics; Oligodendroglia; Neurons; Cells, Cultured; Mitochondrial Proteins; GTP Phosphohydrolases; Neurogenesis; Lateral Ventricles; Dynamins
PubMed: 38664022
DOI: 10.26508/lsa.202302473 -
Redox Biology Jul 2024The dynamic regulation of mitochondria through fission and fusion is essential for maintaining cellular homeostasis. In this study, we discovered a role of...
The dynamic regulation of mitochondria through fission and fusion is essential for maintaining cellular homeostasis. In this study, we discovered a role of coactivator-associated arginine methyltransferase 1 (CARM1) in mitochondrial dynamics. CARM1 methylates specific residues (R403 and R634) on dynamin-related protein 1 (DRP1). Methylated DRP1 interacts with mitochondrial fission factor (Mff) and forms self-assembly on the outer mitochondrial membrane, thereby triggering fission, reducing oxygen consumption, and increasing reactive oxygen species (ROS) production. This sets in motion a feedback loop that facilitates the translocation of CARM1 from the nucleus to the cytoplasm, enhancing DRP1 methylation and ROS production through mitochondrial fragmentation. Consequently, ROS reinforces the CARM1-DRP1-ROS axis, resulting in cellular senescence. Depletion of CARM1 or DRP1 impedes cellular senescence by reducing ROS accumulation. The uncovering of the above-described mechanism fills a missing piece in the vicious cycle of ROS-induced senescence and contributes to a better understanding of the aging process.
Topics: Mitochondrial Dynamics; Dynamins; Protein-Arginine N-Methyltransferases; Humans; Reactive Oxygen Species; Methylation; Cytoplasm; Cellular Senescence; Mitochondria; Mitochondrial Proteins; Membrane Proteins
PubMed: 38838552
DOI: 10.1016/j.redox.2024.103212 -
Journal of Cell Science Apr 2024Clathrin-mediated endocytosis (CME) is vital for the regulation of plant growth and development through controlling plasma membrane protein composition and cargo uptake....
Clathrin-mediated endocytosis (CME) is vital for the regulation of plant growth and development through controlling plasma membrane protein composition and cargo uptake. CME relies on the precise recruitment of regulators for vesicle maturation and release. Homologues of components of mammalian vesicle scission are strong candidates to be part of the scission machinery in plants, but the precise roles of these proteins in this process are not fully understood. Here, we characterised the roles of the plant dynamin-related protein 2 (DRP2) family (hereafter DRP2s) and SH3-domain containing protein 2 (SH3P2), the plant homologue to recruiters of dynamins, such as endophilin and amphiphysin, in CME by combining high-resolution imaging of endocytic events in vivo and characterisation of the purified proteins in vitro. Although DRP2s and SH3P2 arrive similarly late during CME and physically interact, genetic analysis of the sh3p123 triple mutant and complementation assays with non-SH3P2-interacting DRP2 variants suggest that SH3P2 does not directly recruit DRP2s to the site of endocytosis. These observations imply that, despite the presence of many well-conserved endocytic components, plants have acquired a distinct mechanism for CME.
Topics: Arabidopsis; Arabidopsis Proteins; Clathrin; Dynamins; Endocytosis; GTP-Binding Proteins; Mutation
PubMed: 38506228
DOI: 10.1242/jcs.261720 -
Journal of Cell Science Apr 2024Mitochondrial fission is a tightly regulated process involving multiple proteins and cell signaling. Despite extensive studies on mitochondrial fission factors, our...
Mitochondrial fission is a tightly regulated process involving multiple proteins and cell signaling. Despite extensive studies on mitochondrial fission factors, our understanding of the regulatory mechanisms remains limited. This study shows the critical role of a mitochondrial GTPase, GTPBP8, in orchestrating mitochondrial fission in mammalian cells. Depletion of GTPBP8 resulted in drastic elongation and interconnectedness of mitochondria. Conversely, overexpression of GTPBP8 shifted mitochondrial morphology from tubular to fragmented. Notably, the induced mitochondrial fragmentation from GTPBP8 overexpression was inhibited in cells either depleted of the mitochondrial fission protein Drp1 (also known as DNM1L) or carrying mutated forms of Drp1. Importantly, downregulation of GTPBP8 caused an increase in oxidative stress, modulating cell signaling involved in the increased phosphorylation of Drp1 at Ser637. This phosphorylation hindered the recruitment of Drp1 to mitochondria, leading to mitochondrial fission defects. By contrast, GTPBP8 overexpression triggered enhanced recruitment and assembly of Drp1 at mitochondria. In summary, our study illuminates the cellular function of GTPBP8 as a pivotal modulator of the mitochondrial division apparatus, inherently reliant on its influence on Drp1.
Topics: Humans; Dynamins; GTP Phosphohydrolases; GTP-Binding Proteins; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Oxidative Stress; Phosphorylation; Monomeric GTP-Binding Proteins
PubMed: 38587461
DOI: 10.1242/jcs.261612 -
Experimental Cell Research Aug 2023Vascular endothelial cells (VECs) injury is the first step in the pathogenesis of atherosclerosis (AS). Mitochondrial dysfunction plays a significant role in VECs...
Vascular endothelial cells (VECs) injury is the first step in the pathogenesis of atherosclerosis (AS). Mitochondrial dysfunction plays a significant role in VECs injury, but the underlying mechanisms are still unclear. Here, the human umbilical vein endothelial cells were exposed to 100 μg/mL oxidized low-density lipoprotein for 24 h to establish AS model in vitro. We reported that mitochondrial dynamics disorder is a prominent feature of VECs in AS models and associated with mitochondrial dysfunction. Moreover, the knockdown of dynamin-related protein 1 (DRP1) in AS model significantly alleviated the mitochondrial dynamics disorder and VECs injury. On the contrary, DRP1 overexpression significantly aggravated this injury. Interestingly, atorvastatin (ATV), a classical anti-atherosclerotic drug, prominently inhibited the expression of DRP1 in AS models and similarly alleviated the mitochondrial dynamics disorder and VECs injury in vitro and in vivo. At the same time, we found that ATV alleviated VECs damage but did not significantly reduce lipid concentration in vivo. Our findings provide a potential therapeutic target of AS and a new mechanism of the anti-atherosclerotic effect of ATV.
Topics: Humans; Atorvastatin; Dynamins; Lipoproteins, LDL; Human Umbilical Vein Endothelial Cells; Atherosclerosis; Apoptosis
PubMed: 37315759
DOI: 10.1016/j.yexcr.2023.113688 -
Journal of Virology Oct 2023Although rhabdovirus (MSRV) causes serious fish epidemics worldwide, the detailed mechanism of MSRV entry into host cells remains unknown. Here, we comprehensively...
Although rhabdovirus (MSRV) causes serious fish epidemics worldwide, the detailed mechanism of MSRV entry into host cells remains unknown. Here, we comprehensively investigated the mechanism of MSRV entry into epithelioma (EPC) cells. This study demonstrated that MSRV enters EPC cells via a low pH, dynamin-dependent, microtubule-dependent, and clathrin-mediated endocytosis. Subsequently, MSRV transports from early endosomes to late endosomes and further into lysosomes in a microtubule-dependent manner. The characterization of MSRV entry will further advance the understanding of rhabdovirus cellular entry pathways and provide novel targets for antiviral drug against MSRV infection.
Topics: Animals; Rhabdoviridae; Bass; rab5 GTP-Binding Proteins; Endocytosis; Dynamins; Microtubules; Clathrin; Hydrogen-Ion Concentration; Virus Internalization
PubMed: 37735152
DOI: 10.1128/jvi.00714-23 -
Journal of Cellular and Molecular... May 2024Non-small-cell lung cancer (NSCLC) is a major cause of worldwide cancer death, posing a challenge for effective treatment. Our previous findings showed that Chinese...
Non-small-cell lung cancer (NSCLC) is a major cause of worldwide cancer death, posing a challenge for effective treatment. Our previous findings showed that Chinese herbal medicine (CHM) QiDongNing (QDN) could upregulate the expression of p53 and trigger cell apoptosis in NSCLC. Here, our objective was to investigate the mechanisms of QDN-induced apoptosis enhancement. We chose A549 and NCI-H460 cells for validation in vitro, and LLC cells were applied to form a subcutaneous transplantation tumour model for validation in more depth. Our findings indicated that QDN inhibited multiple biological behaviours, including cell proliferation, cloning, migration, invasion and induction of apoptosis. We further discovered that QDN increased the pro-apoptotic BAX while inhibiting the anti-apoptotic Bcl2. QDN therapy led to a decline in adenosine triphosphate (ATP) and a rise in reactive oxygen species (ROS). Furthermore, QDN elevated the levels of the tumour suppressor p53 and the mitochondrial division factor DRP1 and FIS1, and decreased the mitochondrial fusion molecules MFN1, MFN2, and OPA1. The results were further verified by rescue experiments, the p53 inhibitor Pifithrin-α and the mitochondrial division inhibitor Mdivi1 partially inhibited QDN-induced apoptosis and mitochondrial dysfunction, whereas overexpression of p53 rather increased the efficacy of the therapy. Additionally, QDN inhibited tumour growth with acceptable safety in vivo. In conclusion, QDN induced apoptosis via triggering p53/DRP1-mediated mitochondrial fission in NSCLC cells.
Topics: Animals; Humans; Mice; A549 Cells; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Movement; Cell Proliferation; Drugs, Chinese Herbal; Dynamins; Lung Neoplasms; Mitochondria; Mitochondrial Dynamics; Reactive Oxygen Species; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays
PubMed: 38682742
DOI: 10.1111/jcmm.18353 -
BioRxiv : the Preprint Server For... Mar 2024Dynamins, or dynamin-related proteins (DRPs), are large mechano-sensitive GTPases mediating membrane dynamics or organellar fission/fusion events. encodes three...
UNLABELLED
Dynamins, or dynamin-related proteins (DRPs), are large mechano-sensitive GTPases mediating membrane dynamics or organellar fission/fusion events. encodes three dynamin-like proteins whose functions are poorly understood. Here, we demonstrate that PfDyn2 mediates both apicoplast and mitochondrial fission. Using super-resolution and ultrastructure expansion microscopy, we show that PfDyn2 is expressed in the schizont stage and localizes to both the apicoplast and mitochondria. Super-resolution long-term live cell microscopy shows that PfDyn2-deficient parasites cannot complete cytokinesis because the apicoplast and mitochondria do not undergo fission. Further, the basal complex or cytokinetic ring in cannot fully contract upon PfDyn2 depletion, a phenotype secondary to physical blockage of undivided organelles in the middle of the ring. Our data suggest that organellar fission defects result in aberrant schizogony, generating unsuccessful merozoites. The unique biology of PfDyn2, mediating both apicoplast and mitochondrial fission, has not been observed in other organisms possessing two endosymbiotic organelles.
HIGHLIGHTS
PfDyn2 is essential for schizont-stage development.PfDyn2 mediates both apicoplast and mitochondrial fission.Deficiency of PfDyn2 leads to organellar fission failures and blockage of basal complex contraction.Addition of apicoplast-derived metabolite IPP does not rescue the growth defects.
PubMed: 38559241
DOI: 10.1101/2024.03.15.585229 -
MBio Nov 2023Mitochondria constitute major sources of HO and other reactive oxygen species in eukaryotic cells. The division of these organelles is crucial for multiple processes in...
Mitochondria constitute major sources of HO and other reactive oxygen species in eukaryotic cells. The division of these organelles is crucial for multiple processes in cell biology and relies on highly regulated mechano-GTPases that are oligomerization dependent and belong to the dynamin-related protein family, like DnmA. Our previous work demonstrated that HO induces mitochondrial constriction, division, and remodeling of the outer membrane. Here, we show that HO also induces a DnmA aggregation consistent with higher-order oligomerization and its recruitment to mitochondria. The study of this response uncovered that HO induces the depolymerization and reorganization of actin as well as the critical role that cysteines 450 and 776 play in DnmA function. Our results provide new insights into the mechanisms of reactive oxygen species cell signaling and how they can regulate the dynamics of the actin cytoskeleton and the division of mitochondria and peroxisomes.
PubMed: 38014993
DOI: 10.1128/mbio.02822-23