scholarly journals SENP3 Promotes an Mff-Primed Bcl-xL-Drp1 Interaction Involved in Cell Death Following Ischemia

2021 ◽  
Vol 9 ◽  
Author(s):  
Chun Guo ◽  
Keri L. Hildick ◽  
Juwei Jiang ◽  
Alice Zhao ◽  
Wenbin Guo ◽  
...  
Keyword(s):  
Cell Death ◽  
Mitochondrial Fission ◽  
Glucose Deprivation ◽  
Mitochondrial Outer Membrane ◽  
Sumo Protease ◽  
Survival Pathways ◽  
Sumo Target ◽  
In Cells

Dysregulation of the mitochondrial fission machinery has been linked to cell death following ischemia. Fission is largely dependent on recruitment of Dynamin-related protein 1 (Drp1) to the receptor Mitochondrial fission factor (Mff) located on the mitochondrial outer membrane (MOM). Drp1 is a target for SUMOylation and its deSUMOylation, mediated by the SUMO protease SENP3, enhances the Drp1-Mff interaction to promote cell death in an oxygen/glucose deprivation (OGD) model of ischemia. Another interacting partner for Drp1 is the Bcl-2 family member Bcl-xL, an important protein in cell death and survival pathways. Here we demonstrate that preventing Drp1 SUMOylation by mutating its SUMO target lysines enhances the Drp1-Bcl-xL interaction in vivo and in vitro. Moreover, SENP3-mediated deSUMOylation of Drp1 promotes the Drp1-Bcl-xL interaction. Our data suggest that Mff primes Drp1 binding to Bcl-xL at the mitochondria and that Mff and Bcl-xL can interact directly, independent of Drp1, through their transmembrane domains. Importantly, SENP3 loss in cells subjected to OGD correlates with reduced Drp1-Bcl-xL interaction, whilst recovery of SENP3 levels in cells subjected to reoxygenation following OGD correlates with increased Drp1-Bcl-xL interaction. Expressing a Bcl-xL mutant with defective Drp1 binding reduces OGD plus reoxygenation-evoked cell death. Taken together, our results indicate that SENP3-mediated deSUMOlyation promotes an Mff-primed Drp1-Bcl-xL interaction that contributes to cell death following ischemia.

scholarly journals miR-182-5p and miR-378a-3p regulate ferroptosis in I/R-induced renal injury

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Chenguang Ding ◽  
Xiaoming Ding ◽  
Jin Zheng ◽  
Bo Wang ◽  
Yang Li ◽  
...  
Keyword(s):  
Cell Death ◽  
Renal Injury ◽  
Molecular Mechanisms ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Luciferase Reporter ◽  
Renal Tubular Cell ◽  
In Cells

Abstract Renal tubular cell death is the key factor of the pathogenesis of ischemia/reperfusion (I/R) kidney injury. Ferroptosis is a type of regulated cell death (RCD) found in various diseases. However, the underlying molecular mechanisms related to ferroptosis in renal I/R injury remain unclear. In the present study, we investigated the regulatory role of microRNAs on ferroptosis in I/R-induced renal injury. We established the I/R-induced renal injury model in rats, and H/R induced HK-2 cells injury in vitro. CCK-8 was used to measure cell viability. Fe2+ and ROS levels were assayed to evaluate the activation of ferroptosis. We performed RNA sequencing to profile the miRNAs expression in H/R-induced injury and ferroptosis. Western blot analysis was used to detect the protein expression. qRT-PCR was used to detect the mRNA and miRNA levels in cells and tissues. We further used luciferase reporter assay to verify the direct targeting effect of miRNA. We found that ischemia/reperfusion-induced ferroptosis in rat’s kidney. We identified that miR-182-5p and miR-378a-3p were upregulated in the ferroptosis and H/R-induced injury, and correlates reversely with glutathione peroxidases 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression in renal I/R injury tissues, respectively. In vitro studies showed that miR-182-5p and miR-378a-3p induced ferroptosis in cells. We further found that miR-182-5p and miR-378a-3p regulated the expression of GPX4 and SLC7A11 negatively by directly binding to the 3′UTR of GPX4 and SLC7A11 mRNA. In vivo study showed that silencing miR-182-5p and miR-378a-3p alleviated the I/R-induced renal injury in rats. In conclusion, we demonstrated that I/R induced upregulation of miR-182-5p and miR-378a-3p, leading to activation of ferroptosis in renal injury through downregulation of GPX4 and SLC7A11.

scholarly journals Repeated hypoglycemia blunts the responsiveness of glucose-inhibited GHRH neurons by remodeling neural inputs and disrupting mitochondrial structure and function

2019 ◽  
Author(s):  
M Bayne ◽  
A Alvarsson ◽  
K Devarakonda ◽  
R Li ◽  
M Jimenez-Gonzalez ◽  
...  
Keyword(s):  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Glucose Deprivation ◽  
Glucose Sensing ◽  
Diabetic Patients ◽  
Hypoglycemia Unawareness ◽  
Atp Production ◽  
Low Glucose

AbstractHypoglycemia is a frequent complication of diabetes, limiting therapy and increasing morbidity and mortality. With recurrent hypoglycemia, the counter-regulatory response (CRR) to decreased blood glucose is blunted, resulting in hypoglycemia unawareness. The mechanisms leading to these blunted effects remain incompletely understood. Here, we identify, with in situ hybridization, immunohistochemistry and the tissue clearing capability of iDisco, that GHRH neurons represent a unique population of arcuate nucleus neurons activated by glucose deprivation in vivo. Repeated glucose deprivation reduces GHRH neuron activation and remodels excitatory and inhibitory inputs to GHRH neurons. We show low glucose sensing is coupled to GHRH neuron depolarization, decreased ATP production and mitochondrial fusion. Repeated hypoglycemia attenuates these responses during low glucose. By maintaining mitochondrial length with the small molecule, mdivi-1, we preserved hypoglycemia sensitivity in vitro and in vivo. Our findings present possible mechanisms for the blunting of the CRR, broaden significantly our understanding of the structure of GHRH neurons and for the fist time, propose that mitochondrial dynamics play an important role in hypoglycemia unawareness. We conclude that interventions targeting mitochondrial fission in GHRH neurons may offer a new pathway to prevent hypoglycemia unawareness in diabetic patients.

Abstract TP270: Adipose Derived Mesenchymal Stem Cells Reduce Autophagic Flux After Ischemic Stroke in Mice via Extracellular Vesicle Transfer of MiR-25-3p

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Yaoyun Kuang ◽  
Xuan Zheng ◽  
Lin Zhang ◽  
Irina Graf ◽  
Mathias Bähr ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Mesenchymal Stem Cells ◽  
Glucose Deprivation ◽  
Neurological Recovery ◽  
Signaling Cascades ◽  
Autophagic Flux ◽  
Primary Neurons

Transplantation of mesenchymal stem cells (MSCs) yields neuroprotection and enhanced neurological recovery in pre-clinical stroke models, which is mediated by the secretion of extracellular vesicles (EVs). The latter are a heterogenous group of vesicles containing microvesicles, exosomes, and apoptotic bodies. The neuroprotective cargo of EVs, however, has not yet been identified. To investigate such a cargo and its underlying mechanism, we designed a series of in vitro and in vivo experiments. Primary neurons were exposed to oxygen-glucose-deprivation (OGD) and co-cultured with either adipose-derived MSCs (ADMSCs) or treated with ADMSC-secreted EVs. As expected, both ADMSCs and ADMSC-secreted EVs significantly reduced neuronal death after 12 h of OGD and 24 h of reoxygenation, showing no difference between the two treatment groups. Screening for various signaling cascades being involved in the interaction between ADMSCs and neurons revealed a decreased autophagic flux as well as a declined p53-Bnip3 activity. However, these signaling cascades were significantly blocked when ADMSCs were pretreated with the inhibitor of exosomal secretion GW4869. In light of miR-25-3p being the most highly expressed miRNA in ADMSC-EVs interacting with the p53 pathway, further in vitro work focused on this pathway. Treatment with a miR-25-3p oligonucleotide mimic reduced cell death, whereas the anti-oligonucleotide increased autophagic flux and cell death by modulating p53-Bnip3 signaling in primary neurons exposed to OGD. Likewise, native ADMSC-EVs but not EVs obtained from ADMSCs pretreated with the anti-miR-25-3p oligonucleotide (ADMSC-EVs anti-miR-25-3p ) confirmed the aforementioned in vitro observations in C57BL6 mice exposed to cerebral ischemia. Infarct size was reduced and neurological recovery was increased in mice treated with native ADMSC-EVs when compared to ADMSC-EVs anti-miR-25-3p . As such, ADMSCs induce neuroprotection - at least in part - by improved autophagic flux through secreted EVs containing miR-25-3p. Hence, our work for the first time uncovers a key factor in naturally secreted ADMSC-EVs for the regulation of autophagy and induction of neuroprotection in a pre-clinical stroke model.

scholarly journals Regorafenib Alteration of the BCL-xL/MCL-1 Ratio Provides a Therapeutic Opportunity for BH3-Mimetics in Hepatocellular Carcinoma Models

Cancers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 332 ◽  
Author(s):  
Blanca Cucarull ◽  
Anna Tutusaus ◽  
Miguel Subías ◽  
Milica Stefanovic ◽  
Tania Hernáez-Alsina ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Death ◽  
Hepatoma Cell ◽  
Mitochondrial Outer Membrane ◽  
Cytochrome C Release ◽  
Multikinase Inhibitor ◽  
Bh3 Mimetics ◽  
Mitochondrial Outer Membrane Permeabilization

Background: The multikinase inhibitor regorafenib, approved as second-line treatment for hepatocellular carcinoma (HCC) after sorafenib failure, may induce mitochondrial damage. BH3-mimetics, inhibitors of specific BCL-2 proteins, are valuable drugs in cancer therapy to amplify mitochondrial-dependent cell death. Methods: In in vitro and in vivo HCC models, we tested regorafenib’s effect on the BCL-2 network and the efficacy of BH3-mimetics on HCC treatment. Results: In hepatoma cell lines and Hep3B liver spheroids, regorafenib cytotoxicity was potentiated by BCL-xL siRNA transfection or pharmacological inhibition (A-1331852), while BCL-2 antagonism had no effect. Mitochondrial outer membrane permeabilization, cytochrome c release, and caspase-3 activation mediated A-1331852/regorafenib-induced cell death. In a patient-derived xenograft (PDX) HCC model, BCL-xL inhibition stimulated regorafenib activity, drastically decreasing tumor growth. Moreover, regorafenib-resistant HepG2 cells displayed increased BCL-xL and reduced MCL-1 expression, while A-1331852 reinstated regorafenib efficacy in vitro and in a xenograft mouse model. Interestingly, BCL-xL levels, associated with poor prognosis in liver and colorectal cancer, and the BCL-xL/MCL-1 ratio were detected as being increased in HCC patients. Conclusion: Regorafenib primes tumor cells to BH3-mimetic-induced cell death, allowing BCL-xL inhibition with A-1331852 or other strategies based on BCL-xL degradation to enhance regorafenib efficacy, offering a novel approach for HCC treatment, particularly for tumors with an elevated BCL-xL/MCL-1 ratio.

scholarly journals Inhibition of SUMO-independent PML oligomerization by the human cytomegalovirus IE1 protein

2006 ◽  
Vol 87 (8) ◽  
pp. 2181-2190 ◽  
Author(s):  
Heejung Kang ◽  
Eui Tae Kim ◽  
Hye-Ra Lee ◽  
Jung-Jin Park ◽  
Yoon Young Go ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Insect Cells ◽  
Inhibitory Effect ◽  
Sumo Protease ◽  
Sumo Proteases ◽  
Specific Protease ◽  
Infected Cells ◽  
In Cells

In human cytomegalovirus-infected cells, the immediate-early IE1 protein disrupts the subnuclear structures known as the PML oncogenic domains or PODs, via the induction of PML desumoylation. This activity correlates with the functions of IE1 in transcriptional regulation and in the stimulation of lytic infection. Here, the effects of IE1 in induction of desumoylation of PML were characterized. IE1 did not interfere with the formation of sumoylated forms of PML in vitro. In in vitro assays using the sumoylated proteins, a SUMO-specific protease SENP1 desumoylated both PML and IE1. However, the IE1 proteins generated from bacteria or insect cells were unable to desumoylate PML in the same conditions. Although both IE1 and SUMO proteases such as SENP1, Axam and SuPr-1 efficiently desumoylated PML in co-transfection assays, they exerted different effects on the localization of PML. In cells transfected with either SENP1 or SuPr-1, the number of PML foci was reduced significantly and these remnant PML foci were devoid of SUMO-1 signals. However, in cells co-transfected with both SUMO proteases and IE1, these SUMO-independent PML foci were also completely disrupted. Furthermore, IE1, but not SENP1, was shown to disrupt the PML foci generated via transfection of a sumoylation-deficient mutant of PML. These data suggest that IE1 exhibits neither an inhibitory effect on sumoylation of PML nor intrinsic SUMO protease activity against PML in vitro. The finding that IE1 is capable of disrupting SUMO-independent PML aggregates suggests that inhibition of PML oligomerization by IE1 may play an important role in inducing PML desumoylation in vivo.

scholarly journals Curcumin a Multifaceted Compound with Hormetic Behaviour that Mediates an Intricate Crosstalk between Mitochondrial Biogenesis, Mitophagy, Mitophagic Death and Apoptosis

2017 ◽  
Author(s):  
Nathan Earl Rainey ◽  
Aoula Moustapha ◽  
Raphaelle Parker ◽  
Patrice Xavier Petit
Keyword(s):  
Cell Death ◽  
Mitochondrial Biogenesis ◽  
Calcium Release ◽  
Mitochondrial Outer Membrane ◽  
Protective Mechanism ◽  
High Dose ◽  
M Cell ◽  
Mitochondrial Outer Membrane Permeabilization

Curcumin, found in the rhizome of turmeric, has extensive therapeutic promises via its antioxidant, anti-inflammatory, and antiproliferative properties. Preclinical in vitro and in vivo data have shown curcumin to be an effective treatment for multiple cancers. These effects are drived by curcumin's ability to induce G2/M cell cycle arrest, induction of autophagy, activation of apoptotic pathways, disruption of molecular signaling, inhibition of invasion and metastasis, and by increasing the efficacy of existing chemotherapeutics. Here we focused on the hormetic behaviour of curcumin. Frequently, low doses of toxins and other stressors not only are harmless but also activate an adaptive stress whereas high dose activates acute responses like autophagy and cell death. This phenomenon is referred to as hormesis. Many molecules that cause cell death elicite an initial autophagic step that is a cytoprotective mechanism relying on elimination of dysfunctional structures intracellular, notably by mitophagy. This phenomenon is considered as a primarily protective mechanism against stressors. At higher doses, cells undergo mitochondrial outer membrane permeabilization due to calcium release from the endoplasmic reticulum and die. Herein, we address the complex crosstalk between the induced mitochondrial biogenesis, mitochondrial destabilization accompanied by mitophagy and cell death that can also be at play.

scholarly journals BDNF-Overexpressing Engineered Mesenchymal Stem Cells Enhances Their Therapeutic Efficacy against Severe Neonatal Hypoxic Ischemic Brain Injury

2021 ◽  
Vol 22 (21) ◽  
pp. 11395
Author(s):  
So Yoon Ahn ◽  
Dong Kyung Sung ◽  
Yun Sil Chang ◽  
Se In Sung ◽  
Young Eun Kim ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Mesenchymal Stem Cells ◽  
Brain Injury ◽  
Therapeutic Efficacy ◽  
Inflammatory Responses ◽  
Apoptotic Cell ◽  
Glucose Deprivation

We investigated whether irradiated brain-derived neurotropic factor (BDNF)-overexpressing engineered human mesenchymal stem cells (BDNF-eMSCs) improve paracrine efficiency and, thus, the beneficial potency of naïve MSCs against severe hypoxic ischemic (HI) brain injury in newborn rats. Irradiated BDNF-eMSCs hyper-secreted BDNF > 10 fold and were >5 fold more effective than naïve MSCs in attenuating the oxygen-glucose deprivation-induced increase in cytotoxicity, oxidative stress, and cell death in vitro. Only the irradiated BDNF-eMSCs, but not naïve MSCs, showed significant attenuating effects on severe neonatal HI-induced short-term brain injury scores, long-term progress of brain infarct, increased apoptotic cell death, astrogliosis and inflammatory responses, and impaired negative geotaxis and rotarod tests in vivo. Our data, showing better paracrine potency and the resultant better therapeutic efficacy of the irradiated BDNF-eMSCs, compared to naïve MSCs, suggest that MSCs transfected with the BDNF gene might represent a better, new therapeutic strategy against severe neonatal HI brain injury.

scholarly journals Adipose-Derived Mesenchymal Stem Cells-Derived Exosomes Carry MicroRNA-671 to Alleviate Myocardial Infarction Through Inactivating the TGFBR2/Smad2 Axis

Inflammation ◽  
2021 ◽  
Author(s):  
Xue Wang ◽  
Yuhai Zhu ◽  
Chengcheng Wu ◽  
Wennan Liu ◽  
Yujie He ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Glucose Deprivation ◽  
Bioinformatic Analysis ◽  
In Cells

Abstract Mesenchymal stem cells (MSCs) and their derived extracellular vesicles have been reported as promising tools for the management of heart disease. The aim of this study was to explore the function of adipose-derived MSCs (adMSCs)-derived exosomes (Exo) in the progression of myocardial infarction (MI) and the molecules involved. Mouse cardiomyocytes were treated with oxygen-glucose deprivation (OGD) to mimic an MI condition in vitro. The adMSCs-derived Exo were identified and administrated into the OGD-treated cardiomyocytes, and then the viability and apoptosis of cells, and the secretion of fibrosis- and inflammation-related cytokines in cells were determined. Differentially expressed microRNAs (miRNAs) in cells after Exo treatment were screened using a microarray analysis. The downstream molecules regulated by miR-671 were explored through bioinformatic analysis. Involvements of miR-671 and transforming growth factor beta receptor 2 (TGFBR2) in the exosome-mediated events were confirmed by rescue experiments. A murine model with MI was induced and treated with Exo for functional experiments in vivo. Compared to phosphate-buffered saline treatment, the Exo treatment significantly enhanced viability while reduced apoptosis of cardiomyocytes, and in reduced myocardial fibrosis and inflammation both in vitro and in vivo. miR-671 was significantly upregulated in cells after Exo treatment. Downregulation of miR-671 blocked the protective functions of Exo. miR-671 targeted TGFBR2 and suppressed phosphorylation of Smad2. Artificial downregulation of TGFBR2 enhanced viability of the OGD-treated cardiomyocytes. This study suggested that adMSC-derived exosomal miR-671 directly targets TGFBR2 and reduces Smad2 phosphorylation to alleviate MI-like symptoms both in vivo and in vitro.

scholarly journals FLIPL Protects Neurons against In Vivo Ischemia and In Vitro Glucose Deprivation-Induced Cell Death

2007 ◽  
Vol 27 (25) ◽  
pp. 6633-6646 ◽  
Author(s):  
E. Taoufik ◽  
S. Valable ◽  
G. J. Muller ◽  
M. L. Roberts ◽  
D. Divoux ◽  
...  
Keyword(s):  
Cell Death ◽  
Glucose Deprivation

scholarly journals Mff is an essential factor for mitochondrial recruitment of Drp1 during mitochondrial fission in mammalian cells

2010 ◽  
Vol 191 (6) ◽  
pp. 1141-1158 ◽  
Author(s):  
Hidenori Otera ◽  
Chunxin Wang ◽  
Megan M. Cleland ◽  
Kiyoko Setoguchi ◽  
Sadaki Yokota ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Mitochondrial Fission ◽  
Conditional Knockout ◽  
Mitochondrial Outer Membrane ◽  
Essential Factor ◽  
Colon Carcinoma Cells ◽  
Target Membrane ◽  
Guanosine Triphosphatase

The cytoplasmic dynamin-related guanosine triphosphatase Drp1 is recruited to mitochondria and mediates mitochondrial fission. Although the mitochondrial outer membrane (MOM) protein Fis1 is thought to be a Drp1 receptor, this has not been confirmed. To analyze the mechanism of Drp1 recruitment, we manipulated the expression of mitochondrial fission and fusion proteins and demonstrated that (a) mitochondrial fission factor (Mff) knockdown released the Drp1 foci from the MOM accompanied by network extension, whereas Mff overexpression stimulated mitochondrial recruitment of Drp1 accompanied by mitochondrial fission; (b) Mff-dependent mitochondrial fission proceeded independent of Fis1; (c) a Mff mutant with the plasma membrane–targeted CAAX motif directed Drp1 to the target membrane; (d) Mff and Drp1 physically interacted in vitro and in vivo; (e) exogenous stimuli–induced mitochondrial fission and apoptosis were compromised by knockdown of Drp1 and Mff but not Fis1; and (f) conditional knockout of Fis1 in colon carcinoma cells revealed that it is dispensable for mitochondrial fission. Thus, Mff functions as an essential factor in mitochondrial recruitment of Drp1.

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