Doxorubicin impairs cardiomyocyte viability by suppressing transcription factor EB expression and disrupting autophagy

2016 ◽  
Vol 473 (21) ◽  
pp. 3769-3789 ◽  
Author(s):  
Jordan J. Bartlett ◽  
Purvi C. Trivedi ◽  
Pollen Yeung ◽  
Petra C. Kienesberger ◽  
Thomas Pulinilkunnil
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Cathepsin B ◽  
Ex Vivo ◽  
Calcium Flux ◽  
Autophagic Flux ◽  
Mitochondrial Energy Metabolism ◽  
Transcription Factor Eb

Doxorubicin (DOX) is an effective anti-cancer agent. However, DOX treatment increases patient susceptibility to dilated cardiomyopathy. DOX predisposes cardiomyocytes to insult by suppressing mitochondrial energy metabolism, altering calcium flux, and disrupting proteolysis and proteostasis. Prior studies have assessed the role of macroautophagy in DOX cardiotoxicity; however, limited studies have examined whether DOX mediates cardiac injury through dysfunctions in inter- and/or intra-lysosomal signaling events. Lysosomal signaling and function is governed by transcription factor EB (TFEB). In the present study, we hypothesized that DOX caused myocyte injury by impairing lysosomal function and signaling through negative regulation of TFEB. Indeed, we found that DOX repressed cellular TFEB expression, which was associated with impaired cathepsin proteolytic activity across in vivo, ex vivo, and in vitro models of DOX cardiotoxicity. Furthermore, we observed that loss of TFEB was associated with reduction in macroautophagy protein expression, inhibition of autophagic flux, impairments in lysosomal cathepsin B activity, and activation of cell death. Restoration and/or activation of TFEB in DOX-treated cardiomyocytes prevented DOX-induced suppression of cathepsin B activity, reduced DOX-mediated reactive oxygen species (ROS) overproduction, attenuated activation of caspase-3, and improved cellular viability. Collectively, loss of TFEB inhibits lysosomal autophagy, rendering cardiomyocytes susceptible to DOX-induced proteotoxicity and injury. Our data reveal a novel mechanism wherein DOX primes cardiomyocytes for cell death by depleting cellular TFEB.

scholarly journals SB365, Pulsatilla Saponin D Induces Caspase-Independent Cell Death and Augments the Anticancer Effect of Temozolomide in Glioblastoma Multiforme Cells

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3230 ◽  
Author(s):  
Jun-Man Hong ◽  
Jin-Hee Kim ◽  
Hyemin Kim ◽  
Wang Jae Lee ◽  
Young-il Hwang
Keyword(s):  
Cell Death ◽  
Glioblastoma Multiforme ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cathepsin B ◽  
Cytotoxic Effect ◽  
Cancer Cell Lines ◽  
Autophagic Flux

SB365, a saponin D extracted from the roots of Pulsatilla koreana, has been reported to show cytotoxicity in several cancer cell lines. We investigated the effects of SB365 on U87-MG and T98G glioblastoma multiforme (GBM) cells, and its efficacy in combination with temozolomide for treating GBM. SB365 exerted a cytotoxic effect on GBM cells not by inducing apoptosis, as in other cancer cell lines, but by triggering caspase-independent cell death. Inhibition of autophagic flux and neutralization of the lysosomal pH occurred rapidly after application of SB365, followed by deterioration of mitochondrial membrane potential. A cathepsin B inhibitor and N-acetyl cysteine, an antioxidant, partially recovered cell death induced by SB365. SB365 in combination with temozolomide exerted an additive cytotoxic effect in vitro and in vivo. In conclusion, SB365 inhibits autophagic flux and induces caspase-independent cell death in GBM cells in a manner involving cathepsin B and mainly reactive oxygen species, and its use in combination with temozolomide shows promise for the treatment of GBM.

scholarly journals The translocator protein (TSPO) is prodromal to mitophagy loss in neurotoxicity

2021 ◽  
Author(s):  
Michele Frison ◽  
Danilo Faccenda ◽  
Rosella Abeti ◽  
Manuel Rigon ◽  
Daniela Strobbe ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Translocator Protein ◽  
Redox Stress ◽  
Cellular Redox ◽  
Extracellular Signal ◽  
Transcription Factor Eb ◽  
Stress Susceptibility

AbstractDysfunctional mitochondria characterise Parkinson’s Disease (PD). Uncovering etiological molecules, which harm the homeostasis of mitochondria in response to pathological cues, is therefore pivotal to inform early diagnosis and therapy in the condition, especially in its idiopathic forms. This study proposes the 18 kDa Translocator Protein (TSPO) to be one of those. Both in vitro and in vivo data show that neurotoxins, which phenotypically mimic PD, increase TSPO to enhance cellular redox-stress, susceptibility to dopamine-induced cell death, and repression of ubiquitin-dependent mitophagy. TSPO amplifies the extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) signalling, forming positive feedback, which represses the transcription factor EB (TFEB) and the controlled production of lysosomes. Finally, genetic variances in the transcriptome confirm that TSPO is required to alter the autophagy–lysosomal pathway during neurotoxicity.

scholarly journals RIP3 impedes transcription factor EB to suppress autophagic degradation in septic acute kidney injury

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Ruizhao Li ◽  
Xingchen Zhao ◽  
Shu Zhang ◽  
Wei Dong ◽  
Li Zhang ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Transcription Factor ◽  
Nuclear Translocation ◽  
Kidney Injury ◽  
Septic Acute Kidney Injury ◽  
Transcription Factor Eb ◽  
Autophagic Degradation ◽  
Lps Treatment

AbstractAutophagy is an important renal-protective mechanism in septic acute kidney injury (AKI). Receptor interacting protein kinase 3 (RIP3) has been implicated in the renal tubular injury and renal dysfunction during septic AKI. Here we investigated the role and mechanism of RIP3 on autophagy in septic AKI. We showed an activation of RIP3, accompanied by an accumulation of the autophagosome marker LC3II and the autophagic substrate p62, in the kidneys of lipopolysaccharide (LPS)-induced septic AKI mice and LPS-treated cultured renal proximal tubular epithelial cells (PTECs). The lysosome inhibitor did not further increase the levels of LCII or p62 in LPS-treated PTECs. Moreover, inhibition of RIP3 attenuated the aberrant accumulation of LC3II and p62 under LPS treatment in vivo and in vitro. By utilizing mCherry-GFP-LC3 autophagy reporter mice in vivo and PTECs overexpression mRFP-GFP-LC3 in vitro, we observed that inhibition of RIP3 restored the formation of autolysosomes and eliminated the accumulated autophagosomes under LPS treatment. These results indicated that RIP3 impaired autophagic degradation, contributing to the accumulation of autophagosomes. Mechanistically, the nuclear translocation of transcription factor EB (TFEB), a master regulator of the lysosome and autophagy pathway, was inhibited in LPS-induced mice and LPS-treated PTECs. Inhibition of RIP3 restored the nuclear translocation of TFEB in vivo and in vitro. Co-immunoprecipitation further showed an interaction of RIP3 and TFEB in LPS-treated PTECs. Also, the expression of LAMP1 and cathepsin B, two potential target genes of TFEB involved in lysosome function, were decreased under LPS treatment in vivo and in vitro, and this decrease was rescued by inhibiting RIP3. Finally, overexpression of TFEB restored the autophagic degradation in LPS-treated PTECs. Together, the present study has identified a pivotal role of RIP3 in suppressing autophagic degradation through impeding the TFEB-lysosome pathway in septic AKI, providing potential therapeutic targets for the prevention and treatment of septic AKI.

scholarly journals Bcl-2 overexpression in type II epithelial cells does not prevent hyperoxia-induced acute lung injury in mice

2010 ◽  
Vol 299 (3) ◽  
pp. L312-L322 ◽  
Author(s):  
Isabelle Métrailler-Ruchonnet ◽  
Alessandra Pagano ◽  
Stéphanie Carnesecchi ◽  
Karim Khatib ◽  
Pedro Herrera ◽  
...  
Keyword(s):  
Cell Death ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Ex Vivo ◽  
Lung Damage ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lung Weight

Bcl-2 is an anti-apoptotic molecule preventing oxidative stress damage and cell death. We have previously shown that Bcl-2 is able to prevent hyperoxia-induced cell death when overexpressed in a murine fibrosarcoma cell line L929. We hypothesized that its specific overexpression in pulmonary epithelial type II cells could prevent hyperoxia-induced lung injury by protecting the epithelial side of the alveolo-capillary barrier. In the present work, we first showed that in vitro Bcl-2 can rescue murine pulmonary epithelial cells (MLE12) from oxygen-induced cell apoptosis, as shown by analysis of LDH release, annexin V/propidium staining, and caspase-3 activity. We then generated transgenic mice overexpressing specifically Bcl-2 in lung epithelial type II cells under surfactant protein C (SP-C) promoter (Tg-Bcl-2) and exposed them to hyperoxia. Bcl-2 did not hinder hyperoxia-induced mitochondria and DNA oxidative damage of type II cell in vivo. Accordingly, lung damage was identical in both Tg-Bcl-2 and littermate mice strains, as measured by lung weight, bronchoalveolar lavage, and protein content. Nevertheless, we observed a significant lower number of TUNEL-positive cells in type II cells isolated from Tg-Bcl-2 mice exposed to hyperoxia compared with cells isolated from littermate mice. In summary, these results show that although Bcl-2 overexpression is able to prevent hyperoxia-induced cell death at single cell level in vitro and ex vivo, it is not sufficient to prevent cell death of parenchymal cells and to protect the lung from acute damage in mice.

scholarly journals A Novel Transcription Factor, ERD15 (Early Responsive to Dehydration 15), Connects Endoplasmic Reticulum Stress with an Osmotic Stress-induced Cell Death Signal

2011 ◽  
Vol 286 (22) ◽  
pp. 20020-20030 ◽  
Author(s):  
Murilo S. Alves ◽  
Pedro A. B. Reis ◽  
Silvana P. Dadalto ◽  
Jerusa A. Q. A. Faria ◽  
Elizabeth P. B. Fontes ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Transcription Factor ◽  
Osmotic Stress ◽  
Er Stress ◽  
Unfolded Protein ◽  
Eukaryotic Organisms ◽  
Protein Response

As in all other eukaryotic organisms, endoplasmic reticulum (ER) stress triggers the evolutionarily conserved unfolded protein response in soybean, but it also communicates with other adaptive signaling responses, such as osmotic stress-induced and ER stress-induced programmed cell death. These two signaling pathways converge at the level of gene transcription to activate an integrated cascade that is mediated by N-rich proteins (NRPs). Here, we describe a novel transcription factor, GmERD15 (Glycine max Early Responsive to Dehydration 15), which is induced by ER stress and osmotic stress to activate the expression of NRP genes. GmERD15 was isolated because of its capacity to stably associate with the NRP-B promoter in yeast. It specifically binds to a 187-bp fragment of the NRP-B promoter in vitro and activates the transcription of a reporter gene in yeast. Furthermore, GmERD15 was found in both the cytoplasm and the nucleus, and a ChIP assay revealed that it binds to the NRP-B promoter in vivo. Expression of GmERD15 in soybean protoplasts activated the NRP-B promoter and induced expression of the NRP-B gene. Collectively, these results support the interpretation that GmERD15 functions as an upstream component of stress-induced NRP-B-mediated signaling to connect stress in the ER to an osmotic stress-induced cell death signal.

mTOR inhibition by metformin impacts monosodium urate crystal–induced inflammation and cell death in gout: a prelude to a new add-on therapy?

2019 ◽  
Vol 78 (5) ◽  
pp. 663-671 ◽  
Author(s):  
Nadia Vazirpanah ◽  
Andrea Ottria ◽  
Maarten van der Linden ◽  
Catharina G K Wichers ◽  
Mark Schuiveling ◽  
...  
Keyword(s):  
Cell Death ◽  
Immune Cells ◽  
Metabolic Diseases ◽  
Ex Vivo ◽  
Mtor Pathway ◽  
Monosodium Urate ◽  
Mtor Inhibition ◽  
Msu Crystals

ObjectiveGout is the most common inflammatory arthritis worldwide, and patients experience a heavy burden of cardiovascular and metabolic diseases. The inflammation is caused by the deposition of monosodium urate (MSU) crystals in tissues, especially in the joints, triggering immune cells to mount an inflammatory reaction. Recently, it was shown that MSU crystals can induce mechanistic target of rapamycin (mTOR) signalling in monocytes encountering these crystals in vitro. The mTOR pathway is strongly implicated in cardiovascular and metabolic disease. We hypothesised that inhibiting this pathway in gout might be a novel avenue of treatment in these patients, targeting both inflammation and comorbidities.Methods We used a translational approach starting from ex vivo to in vitro and back to in vivo.ResultsWe show that ex vivo immune cells from patients with gout exhibit higher expression of the mTOR pathway, which we can mimic in vitro by stimulating healthy immune cells (B lymphocytes, monocytes, T lymphocytes) with MSU crystals. Monocytes are the most prominent mTOR expressers. By using live imaging, we demonstrate that monocytes, on encountering MSU crystals, initiate cell death and release a wide array of proinflammatory cytokines. By inhibiting mTOR signalling with metformin or rapamycin, a reduction of cell death and release of inflammatory mediators was observed. Consistent with this, we show that patients with gout who are treated with the mTOR inhibitor metformin have a lower frequency of gout attacks.ConclusionsWe propose mTOR inhibition as a novel therapeutic target of interest in gout treatment.

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.

Potential TH9402-Based ECP Treatment for cGvHD Patients.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 5119-5119
Author(s):  
Annie Levesque ◽  
Ann-Louise Savard ◽  
Denis-Claude Roy ◽  
Francine Foss ◽  
Christian Scotto
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Chronic Phase ◽  
Dose Effect ◽  
Peripheral Blood Mononuclear ◽  
Hematopoietic Stem

Abstract Although the risk of graft versus host disease (GvHD) can be reduced by improved donor-recipient matching and by the depletion of T cells before transplantation, GvHD still develops in 30–70% of allogeneic hematopoietic stem cell transplantation (HSCT) patients. The chronic phase of the disease (cGvHD), for which the pathogenesis is similar to autoimmune diseases, involves profound immune dysregulation leading to both immunodeficiency and autoimmunity. Standard therapies for cGvHD such as corticosteroids and immunosuppressants are associated with high toxicity and have demonstrated limited efficacy in patients with extensive disease. Extracorporeal photopheresis (ECP) has been shown by others in the clinic as a non-aggressive and beneficial alternative treatment for cGvHD, inducing Th1/Th2 immunomodulation that restores immunological tolerance. Celmed has developed an alternative approach to eliminate immunoreactive T cells using the Theralux™ photodynamic cell therapy (PDT) system based on the use of the rhodamine-123 derivative TH9402 illuminated ex vivo with a visible light source (λ =514nm). It has been suggested that the apoptotic cells, when returned to the patient, may be able to modulate the immune system as seen with other ECP methods. We aimed to evaluate in vivo and in vitro the possibility of also using the Theralux™ system in the ECP setting. A preliminary mouse model suggested that splenic T cells pre-treated with the Theralux™ system were able to induce an improvement of overall survival (p<0.05) in mice with acute GvHD. Additionally, we developed a simplified PDT process and conducted a series of experiments with peripheral blood mononuclear cells (PBMCs) isolated from healthy volunteers. These studies have shown that the intra- and inter-donor variability in TH9402 incorporation are very low (~5% and 10%, respectively). A dose-effect study has shown a relationship of the PDT conditions with the levels of cell death, allowing significant control of the level of apoptosis induced. Phenotypic analyses have shown that this process results in an increase of AnnexinV positive cells as well as a decrease in the absolute number of CD3+ cells, CD19+/CD20+ cells and CD14+ cells and an increase in CD11c+ cells. This would suggest that apoptosis could be induced in both autoreactive T and B cells which could potentially stimulate an immune response against them. Moreover, the increase in CD11c+ cells combined with the decrease in CD14+ cells could reflect the maturation of macrophages into dendritic cells that are very potent antigen presenting cells. The mechanism by which these specific PDT conditions induce cell death is still under investigation but preliminary studies have shown that the cell death in unselected resting PBMCs may be caspase-independent. Finally, the evaluation of the effect of PDT on samples from cGvHD patients also demonstrated the capacity of this treatment strategy to induce apoptosis in these cells. Based on these data, we intend to begin a pilot clinical study evaluating two controlled PDT conditions inducing different levels of apoptosis in order to assess the safety and biological effect of the Theralux™ ECP system to treat patients with cGvHD.

scholarly journals EXTH-62. PRECLINICAL EFFICACY OF THE IMIPRIDONE ONC-206 AGAINST MEDULLOBLASTOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii100-ii101
Author(s):  
Tobey MacDonald ◽  
Anshu Malhotra ◽  
Jingbo Liu ◽  
Hongying Zhang ◽  
Matthew Schneiderjan ◽  
...  
Keyword(s):  
Cell Death ◽  
Malignant Glioma ◽  
Ex Vivo ◽  
Clinical Results ◽  
Normal Brain ◽  
Dependent Manner ◽  
Group 3 ◽  
Dose Dependent

Abstract Treatment for medulloblastoma (MB) is typically ineffective for MYC amplified or metastatic SHH, Group 3 and 4 subgroups. Promising preclinical and clinical results have been obtained for adult and pediatric malignant glioma treated with ONC-201, a selective antagonist of DRD2, a G-protein coupled receptor that regulates prosurvival pathways. Herein, we report the activity of ONC-201 and ONC-206, which has increased non-competitive antagonism of DRD2, against MB. We treated three different MB cell types representative of SHH- and Group 3-like cells, with varied levels of DRD2 expression, and consistently observed increased cell death in a dose-dependent manner at lower doses of ONC-206 compared to ONC-201. We also evaluated ClpP as an additional drug target in MB. ClpP is a mitochondrial protease that has been shown to directly bind and be activated by ONC 201, and is highly expressed at the protein level across pediatric MB, malignant glioma and ATRT, but not normal brain. We observed that similar to ONC-201, ONC-206 treatment of MB cells induces the restoration of mitochondrial membrane potential to the non-proliferative state, degradation of the mitochondrial substrate SDHB, reduction in survivin and elevation in ATF4 (integrated stress response). Importantly, ONC-206 treatment induced significant cell death of patient-derived SHH, WNT, and Group 3 tumors ex vivo and Group 4 cells in vitro, while having no observable toxicity in normal brain. ONC-206 treatment of a transgenic mouse model of Shh MB in vivo significantly reduces tumor growth and doubles survival time in a dose-dependent manner following 2 weeks of therapy. Additional in vivo data will be reported in preparation for a planned Phase I study of ONC-206 in children with malignant brain tumors.

scholarly journals Ginsenoside Compound K Induces Ros-Mediated Apoptosis and Autophagic Inhibition in Human Neuroblastoma Cells In Vitro and In Vivo

2019 ◽  
Vol 20 (17) ◽  
pp. 4279 ◽  
Author(s):  
Jung-Mi Oh ◽  
Eunhee Kim ◽  
Sungkun Chun
Keyword(s):  
Cell Death ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Autophagic Flux ◽  
Ros Scavenging ◽  
Compound K ◽  
Human Neuroblastoma ◽  
Ginsenoside Compound K

Autophagy can result in cellular adaptation, as well as cell survival or cell death. Modulation of autophagy is increasingly regarded as a promising cancer therapeutic approach. Ginsenoside compound K (CK), an active metabolite of ginsenosides isolated from Panax ginseng C.A. Meyer, has been identified to inhibit growth of cancer cell lines. However, the molecular mechanisms of CK effects on autophagy and neuroblastoma cell death have not yet been investigated. In the present study, CK inhibited neuroblastoma cell proliferation in vitro and in vivo. Treatment by CK also induced the accumulation of sub-G1 population, and caspase-dependent apoptosis in neuroblastoma cells. In addition, CK promotes autophagosome accumulation by inducing early-stage autophagy but inhibits autophagic flux by blocking of autophagosome and lysosome fusion, the step of late-stage autophagy. This effect of CK appears to be mediated through the induction of intracellular reactive oxygen species (ROS) and mitochondria membrane potential loss. Moreover, chloroquine, an autophagy flux inhibitor, further promoted CK-induced apoptosis, mitochondrial ROS induction, and mitochondria damage. Interestingly, those promoted phenomena were rescued by co-treatment with a ROS scavenging agent and an autophagy inducer. Taken together, our findings suggest that ginsenoside CK induced ROS-mediated apoptosis and autophagic flux inhibition, and the combination of CK with chloroquine, a pharmacological inhibitor of autophagy, may be a novel therapeutic potential for the treatment of neuroblastoma.

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