scholarly journals Blockage of Extracellular Signal-Regulated Kinase Exerts an Antitumor Effect via Regulating Energy Metabolism and Enhances the Efficacy of Autophagy Inhibitors by Regulating Transcription Factor EB Nuclear Translocation in Osteosarcoma

2021 ◽  
Vol 9 ◽  
Author(s):  
Man Zhang ◽  
Yang Bai ◽  
Chang Xu ◽  
Yiying Qi ◽  
Jiahong Meng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nuclear Translocation ◽  
Aerobic Glycolysis ◽  
Autophagic Flux ◽  
Antitumor Activities ◽  
Extracellular Signal Regulated Kinase ◽  
Clinical Phase ◽  
Extracellular Signal ◽  
Transcription Factor Eb ◽  
Mitochondria Pathway

Accumulating evidence suggests that extracellular signal-regulated kinase (ERK) is a valuable target molecule for cancer. However, antitumor drugs targeting ERK are still in their clinical phase and no FDA-approved medications exist. In this study, we identified an ERK inhibitor (ERKi; Vx-11e) with potential antitumor activities, which was reflected by the inhibition in the survival and proliferation of Osteosarcoma (OS) cells. Mechanistically, the ERKi regulated autophagic flux by promoting the translocation of transcription factor EB (TFEB) in OS cells, thereby increasing the dependence of OS cells on autophagy and sensitivity to treatment with autophagy inhibitors in OS. Besides, we also found that the ERKi could regulate mitochondrial apoptosis through the ROS/mitochondria pathway and aerobic glycolysis in OS, which also increases the dependence of OS cells on autophagy to clear metabolites to a certain extent. These results may provide a reference for the clinically improved efficacy of ERKis in combination with autophagy inhibitors in the treatment of OS and indicate its potential as a therapeutic agent.

scholarly journals Apolipoprotein M attenuates doxorubicin cardiotoxicity by regulating transcription factor EB

2021 ◽  
Author(s):  
Zhen Guo ◽  
Antonino Picataggi ◽  
Carla Valenzuela Ripoll ◽  
Ezhilarasi Chendamarai ◽  
Amanda Girardi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Plasma Protein ◽  
Nuclear Translocation ◽  
Density Lipoprotein ◽  
Autophagic Flux ◽  
Human Heart Failure ◽  
Apolipoprotein M ◽  
Protein Levels ◽  
Doxorubicin Cardiotoxicity ◽  
Transcription Factor Eb

AbstractApolipoprotein M (ApoM) is an apolipoprotein that binds sphingosine-1-phosphate (S1P) and high-density lipoprotein. ApoM, via S1P signaling, is thought to protect cardiomyocytes from apoptosis, and ApoM plasma protein levels are inversely associated with increased mortality risk in human heart failure. Here, using a doxorubicin cardiotoxicity model, we identify ApoM as a novel regulator of myocardial autophagy. Doxorubicin treatment reduces ApoM plasma protein levels in wild-type mice and humans. Hepatic ApoM transgenic overexpression (ApomTG) protects mice from reductions in cardiac function observed in littermate controls. Though ApoM did not alter markers of DNA damage, apoptosis, Akt signaling, or fibrosis, ApoM prevented doxorubicin-induced reductions in autophagic flux. In the murine myocardium, doxorubicin reduced the nuclear protein content of transcription factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis, in control mice but not ApomTG mice. Furthermore, adeno-associated virus 9 mediated knockdown of TFEB reversed the beneficial effects of ApoM on the myocardium, leading to cardiomyopathy and mortality in ApomTG mice. Our studies provide a mechanistic link between ApoM and the autophagy-lysosome pathway in the murine heart. Our clinical observations that reduced ApoM is associated with mortality may be explained by its role in sustaining autophagy.One sentence summaryApolipoprotein M attenuates doxorubicin cardiotoxicity by preserving nuclear translocation of TFEB and autophagic flux.

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 Glycogen Synthase Kinase 3β and Extracellular Signal-Regulated Kinase Inactivate Heat Shock Transcription Factor 1 by Facilitating the Disappearance of Transcriptionally Active Granules after Heat Shock

1998 ◽  
Vol 18 (11) ◽  
pp. 6624-6633 ◽  
Author(s):  
Bin He ◽  
Yong-Hong Meng ◽  
Nahid F. Mivechi
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Transcriptional Activity ◽  
Glycogen Synthase ◽  
Heat Shock Transcription Factor ◽  
Glycogen Synthase Kinase 3Β ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Gsk 3Β ◽  
Transcription Factor 1

ABSTRACT Heat shock transcription factor 1 (HSF-1) activates the transcription of heat shock genes in eukaryotes. Under normal physiological growth conditions, HSF-1 is a monomer. Its transcriptional activity is repressed by constitutive phosphorylation. Upon activation, HSF-1 forms trimers, acquires DNA binding activity, increases transcriptional activity, and appears as punctate granules in the nucleus. In this study, using bromouridine incorporation and confocal laser microscopy, we demonstrated that newly synthesized pre-mRNAs colocalize to the HSF-1 punctate granules after heat shock, suggesting that these granules are sites of transcription. We further present evidence that glycogen synthase kinase 3β (GSK-3β) and extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) participate in the down regulation of HSF-1 transcriptional activity. Transient increases in the expression of GSK-3β facilitate the disappearance of HSF-1 punctate granules and reduce hsp-70 transcription after heat shock. We have also shown that ERK is the priming kinase for GSK-3β. Taken together, these results indicate that GSK-3β and ERK MAPK facilitate the inactivation of activated HSF-1 after heat shock by dispersing HSF-1 from the sites of transcription.

scholarly journals The role of phagocytosis-dependent activation of TFEB in the clearance of salmonella

2021 ◽  
Author(s):  
Erika Ospina Escobar
Keyword(s):  
Transcription Factor ◽  
Salmonella Typhimurium ◽  
Nuclear Translocation ◽  
Steady Increase ◽  
Phagosome Maturation ◽  
Salmonella Infection ◽  
Complex Interplay ◽  
Transcription Factor Eb ◽  
Insight Into

During phagocytosis, macrophages engulf and sequester pathogens into phagosomes. Phagosomes then fuse with acidic and degradative lysosomes to degrade the internalized pathogen. We previously demonstrated that phagocytosis of IgG-opsonized particles and non-opsonized E.coli causes activation of the Transcription Factor EB (TFEB), which enhances the expression of lysosomal genes, increases the degradative capacity of lysosomes and boosts bactericidal activity. However, pathogens like Salmonella typhimurium have evolved mechanisms to evade and/or alter phagosome maturation to promote their own survival. We investigated: i) whether pathogens like Salmonella can alter TFEB activation and ii) whether phagocytosis-dependent activation of TFEB can counteract the pathogenicity of microorganisms. Here, we show that non-viable (heat-killed) S. typhimurium, pathogenic (EHEC and UPEC) and non-pathogenic E.coli (DH5α) all caused TFEB nuclear translocation in RAW macrophages, while strikingly live S. typhimurium maintained TFEB in the cytosol in the first hours post-infection. By contrast, Salmonella mutants for ΔsifA, ΔsopD2, ΔphoP all triggered TFEB activation in the first hour of infection. However, Salmonella infection eventually triggered a steady increase in nuclear TFEB after 4 h of infection, suggesting a more complex interplay between TFEB and Salmonella infection. We dissected the importance of TFEB activation towards Salmonella survivability by pre-activating TFEB before infection within WT macrophages and macrophages with a CRISPR-based deletion of TFEB. Our work suggests that Salmonella actively interferes with TFEB signaling in order to enhance its own survival. These results could provide insight into using TFEB as a target for the clearance of infections.

scholarly journals The Transcription Factor GATA4 Is Activated by Extracellular Signal-Regulated Kinase 1- and 2-Mediated Phosphorylation of Serine 105 in Cardiomyocytes

2001 ◽  
Vol 21 (21) ◽  
pp. 7460-7469 ◽  
Author(s):  
Qiangrong Liang ◽  
Russell J. Wiese ◽  
Orlando F. Bueno ◽  
Yan-Shan Dai ◽  
Bruce E. Markham ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Phosphorylation Site ◽  
Dominant Negative ◽  
Site Directed Mutagenesis ◽  
Mitogen Activated Protein Kinase ◽  
Cardiomyocyte Hypertrophy ◽  
Hypertrophic Growth ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

ABSTRACT The zinc finger-containing transcription factor GATA4 has been implicated as a critical regulator of multiple cardiac-expressed genes as well as a regulator of inducible gene expression in response to hypertrophic stimulation. Here we demonstrate that GATA4 is itself regulated by the mitogen-activated protein kinase signaling cascade through direct phosphorylation. Site-directed mutagenesis and phospho-specific GATA4 antiserum revealed serine 105 as the primary site involved in agonist-induced phosphorylation of GATA4. Infection of cultured cardiomyocytes with an activated MEK1-expressing adenovirus induced robust phosphorylation of serine 105 in GATA4, while a dominant-negative MEK1-expressing adenovirus blocked agonist-induced phosphorylation of serine 105, implicating extracellular signal-regulated kinase (ERK) as a GATA4 kinase. Indeed, bacterially purified ERK2 protein directly phosphorylated purified GATA4 at serine 105 in vitro. Phosphorylation of serine 105 enhanced the transcriptional potency of GATA4, which was sensitive to U0126 (MEK1 inhibitor) but not SB202190 (p38 inhibitor). Phosphorylation of serine 105 also modestly enhanced the DNA binding activity of bacterially purified GATA4. Finally, induction of cardiomyocyte hypertrophy with an activated MEK1-expressing adenovirus was blocked with a dominant-negative GATA4-engrailed-expressing adenovirus. These results suggest a molecular pathway whereby MEK1-ERK1/2 signaling regulates cardiomyocyte hypertrophic growth through the transcription factor GATA4 by direct phosphorylation of serine 105, which enhances DNA binding and transcriptional activation.

scholarly journals Nerve Growth Factor Activates Extracellular Signal-Regulated Kinase and p38 Mitogen-Activated Protein Kinase Pathways To Stimulate CREB Serine 133 Phosphorylation

1998 ◽  
Vol 18 (4) ◽  
pp. 1946-1955 ◽  
Author(s):  
Jun Xing ◽  
Jon M. Kornhauser ◽  
Zhengui Xia ◽  
Elizabeth A. Thiele ◽  
Michael E. Greenberg
Keyword(s):  
Transcription Factor ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Nerve Growth ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Ribosomal S6 Kinase

ABSTRACT The mechanisms by which growth factor-induced signals are propagated to the nucleus, leading to the activation of the transcription factor CREB, have been characterized. Nerve growth factor (NGF) was found to activate multiple signaling pathways that mediate the phosphorylation of CREB at the critical regulatory site, serine 133 (Ser-133). NGF activates the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases (MAPKs), which in turn activate the pp90 ribosomal S6 kinase (RSK) family of Ser/Thr kinases, all three members of which were found to catalyze CREB Ser-133 phosphorylation in vitro and in vivo. In addition to the ERK/RSK pathway, we found that NGF activated the p38 MAPK and its downstream effector, MAPK-activated protein kinase 2 (MAPKAP kinase 2), resulting in phosphorylation of CREB at Ser-133. Inhibition of either the ERK/RSK or the p38/MAPKAP kinase 2 pathway only partially blocked NGF-induced CREB Ser-133 phosphorylation, suggesting that either pathway alone is sufficient for coupling the NGF signal to CREB activation. However, inhibition of both the ERK/RSK and the p38/MAPKAP kinase 2 pathways completely abolished NGF-induced CREB Ser-133 phosphorylation. These findings indicate that NGF activates two distinct MAPK pathways, both of which contribute to the phosphorylation of the transcription factor CREB and the activation of immediate-early genes.

scholarly journals Intracellular Trafficking and Persistence of Acinetobacter baumannii Requires Transcription Factor EB

mSphere ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Raquel Parra-Millán ◽  
David Guerrero-Gómez ◽  
Rafael Ayerbe-Algaba ◽  
Maria Eugenia Pachón-Ibáñez ◽  
Antonio Miranda-Vizuete ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Acinetobacter Baumannii ◽  
Intracellular Trafficking ◽  
Nuclear Translocation ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Infection Model ◽  
Content Type ◽  
Transcription Factor Eb

ABSTRACT Acinetobacter baumannii is a significant human pathogen associated with hospital-acquired infections. While adhesion, an initial and important step in A. baumannii infection, is well characterized, the intracellular trafficking of this pathogen inside host cells remains poorly studied. Here, we demonstrate that transcription factor EB (TFEB) is activated after A. baumannii infection of human lung epithelial cells (A549). We also show that TFEB is required for the invasion and persistence inside A549 cells. Consequently, lysosomal biogenesis and autophagy activation were observed after TFEB activation which could increase the death of A549 cells. In addition, using the Caenorhabditis elegans infection model by A. baumannii , the TFEB orthologue HLH-30 was required for survival of the nematode to infection, although nuclear translocation of HLH-30 was not required. These results identify TFEB as a conserved key factor in the pathogenesis of A. baumannii . IMPORTANCE Adhesion is an initial and important step in Acinetobacter baumannii infections. However, the mechanism of entrance and persistence inside host cells is unclear and remains to be understood. In this study, we report that, in addition to its known role in host defense against Gram-positive bacterial infection, TFEB also plays an important role in the intracellular trafficking of A. baumannii in host cells. TFEB was activated shortly after A. baumannii infection and is required for its persistence within host cells. Additionally, using the C. elegans infection model by A. baumannii , the TFEB orthologue HLH-30 was required for survival of the nematode to infection, although nuclear translocation of HLH-30 was not required.

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