scholarly journals Oxidative Stress Induces Neuronal Apoptosis Through Suppressing Transcription Factor EB Phosphorylation at Ser467

2018 ◽  
Vol 46 (4) ◽  
pp. 1536-1554 ◽  
Author(s):  
Qian Su ◽  
Bin Zheng ◽  
Chen-yao Wang ◽  
Yun-zhi Yang ◽  
Wen-wen Luo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Cell Apoptosis ◽  
Neuronal Apoptosis ◽  
Nuclear Translocation ◽  
Flow Cytometric Analysis ◽  
Parp Cleavage ◽  
High Concentration ◽  
Akt Inhibitor ◽  
Transcription Factor Eb

Background/Aims: This study determined the role and mechanism of action of transcription factor EB (TFEB) in H2O2-induced neuronal apoptosis. Methods: SH-SY5Y cells were treated with Akt inhibitor/activator and different concentrations of H2O2. Cell apoptosis was detected by flow cytometric analysis. Akt and TFEB phosphorylation and PARP cleavage were determined by Western blotting. HEK293T cells were transfected with different truncated TFEB mutants and HA-Akt-WT; SH-SY5Y cells were transfected with Flag-vector, Flag-TFEB, Flag-TFEB-S467A or Flag-TFEB-S467D; and TFEB interaction with Akt was determined by co-immunoprecipitation and GST pull-down assays. Results: A low concentration of H2O2 induces TFEB phosphorylation at Ser467 and nuclear translocation, facilitating neuronal survival, whereas a high concentration of H2O2 promotes SH-SY5Y cell apoptosis via suppressing TFEB Ser467 phosphorylation and nuclear translocation. The TFEB-S467D mutant is more easily translocated into the nucleus than the non-phosphorylated TFEB-S467A mutant. Further, Akt physically binds to TFEB via its C-terminal tail interaction with the HLH domain of TFEB and phosphorylates TFEB at Ser467. Mutation of TFEB-Ser467 can prevent the phosphorylation of TFEB by Akt, preventing inhibition of oxidative stress-induced apoptosis. Conclusions: Oxidative stress induces neuronal apoptosis through suppressing TFEB phosphorylation at Ser467 by Akt, providing a novel therapeutic strategy for neurodegenerative diseases.

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 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 Down Regulation of SIRT2 Reduced ASS Induced NSCLC Apoptosis Through the Release of Autophagy Components via Exosomes

2020 ◽  
Vol 8 ◽  
Author(s):  
Lei Wang ◽  
Pei Xu ◽  
Xiao Xie ◽  
Fengqing Hu ◽  
Lianyong Jiang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Apoptosis ◽  
Critical Role ◽  
Nsclc Cell ◽  
Dependent Manner ◽  
Cell Metastasis ◽  
Rna Immunoprecipitation ◽  
Transcription Factor Eb

Metastasis of cancer is the main cause of death in many types of cancer. Acute shear stress (ASS) is an important part of tumor micro-environment, it plays a crucial role in tumor invasion and spread. However, less is known about the role of ASS in tumorigenesis and metastasis of NSCLC. In this study, NSCLC cells were exposed to ASS (10 dyn/cm2) to explore the effect of ASS in regulation of autophagy and exosome mediated cell survival. Finally, the influence of SIRT2 on NSCLC cell metastasis was verified in vivo. Our data demonstrates that ASS promotes exosome and autophagy components releasing in a time dependent manner, inhibition of exosome release exacerbates ASS induced NSCLC cell apoptosis. Furthermore, we identified that this function was regulated by sirtuin 2 (SIRT2). And, RNA immunoprecipitation (RIP) assay suggested SIRT2 directly bound to the 3′UTR of transcription factor EB (TFEB) and facilitated its mRNA stability. TFEB is a key transcription factor involved in the regulation of many lysosome related genes and plays a critical role in the fusion of autophagosome and lysosome. Altogether, this data revealed that SIRT2 is a mechanical sensitive protein, and it regulates ASS induced cell apoptosis by modulating the release of exosomes and autophagy components, which provides a promising strategy for the treatment of NSCLCs.

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.

scholarly journals Protein disulfide isomerase inhibition impairs Keap1/Nrf2 signaling and mitochondrial function and induces apoptosis in renal proximal tubular cells

2020 ◽  
Vol 319 (4) ◽  
pp. F686-F696
Author(s):  
Indira D. Pokkunuri ◽  
Mustafa F. Lokhandwala ◽  
Anees Ahmad Banday
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Function ◽  
Cell Apoptosis ◽  
Protein Disulfide Isomerase ◽  
Caspase 3 ◽  
Nuclear Translocation ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Protein Disulfide ◽  
Hk2 Cells

Renal proximal tubular apoptosis plays a critical role in kidney health and disease. However, cellular molecules that trigger renal apoptosis remain elusive. Here, we evaluated the effect of inhibiting protein disulfide isomerase (PDI), a critical thioredoxin chaperone protein, on apoptosis as well as the underlying mechanisms in human renal proximal tubular (HK2) cells. HK2 cells were transfected with PDI-specific siRNA in the absence and presence of an antioxidant, tempol. PDI siRNA transfection resulted in a decrease of ~70% in PDI protein expression and enzyme activity. PDI inhibition increased caspase-3 activity and induced profound cell apoptosis. Mitochondrial function, as assessed by mitochondrial cytochrome c levels, mitochondrial membrane potential, oxygen consumption, and ATP levels, was significantly reduced in PDI-inhibited cells. Also, PDI inhibition caused nuclear factor erythroid 2-related factor 2 (Nrf2; a redox-sensitive transcription factor) cytoplasmic sequestration, decreased superoxide dismutase and glutathione- S-transferase activities, and increased oxidative stress. In PDI-inhibited cells, tempol reduced apoptosis, caspase-3 activity, and oxidative stress and also restored Nrf2 nuclear translocation and mitochondrial function. Silencing Nrf2 in the cells abrogated the beneficial effect of tempol, whereas Kelch-like ECH-associated protein 1 (an Nrf2 regulatory protein) silencing protected cells from PDI inhibitory effects. Collectively, our data indicate that PDI inhibition diminishes Nrf2 nuclear translocation, causing oxidative stress that further triggers mitochondrial dysfunction and renal cell apoptosis. This study suggests an important role for PDI in renal cell apoptosis involving Nrf2 and mitochondrial dysfunction.

scholarly journals FA-97, a New Synthetic Caffeic Acid Phenethyl Ester Derivative, Protects against Oxidative Stress-Mediated Neuronal Cell Apoptosis and Scopolamine-Induced Cognitive Impairment by Activating Nrf2/HO-1 Signaling

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Ting Wan ◽  
Zihao Wang ◽  
Yi Luo ◽  
Yifan Zhang ◽  
Wei He ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cognitive Impairment ◽  
Caffeic Acid ◽  
Cell Apoptosis ◽  
Nuclear Translocation ◽  
Neurodegenerative Disorder ◽  
Neuronal Cell ◽  
Caffeic Acid Phenethyl Ester ◽  
Therapeutic Drug ◽  
Age Related

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder with cognitive deficits, which is becoming markedly more common in the world. Currently, the exact cause of AD is still unclear, and no curative therapy is available for preventing or mitigating the disease progression. Caffeic acid phenethyl ester (CAPE), a natural phenolic compound derived from honeybee hive propolis, has been reported as a potential therapeutic agent against AD, while its application is limited due to the low water solubility and poor bioavailability. Here, caffeic acid phenethyl ester 4-O-glucoside (FA-97) is synthesized. We validate that FA-97 attenuates H2O2-induced apoptosis in SH-SY5Y and PC12 cells and suppresses H2O2-induced oxidative stress by inhibiting the ROS level, malondialdehyde (MDA) level, and protein carbonylation level, as well as induces cellular glutathione (GSH) and superoxide dismutase (SOD). Mechanistically, FA-97 promotes the nuclear translocation and transcriptional activity of Nrf2 associated with the upregulated expression of HO-1 and NQO-1. The prime importance of Nrf2 activation in the neuroprotective and antioxidant effects of FA-97 is verified by Nrf2 siRNA transfection. In addition, FA-97 prevents scopolamine- (SCOP-) induced learning and memory impairments in vivo via reducing neuronal apoptosis and protecting against cholinergic system dysfunction in the hippocampus and cortex. Moreover, the increased MDA level and low total antioxidant capacity in SCOP-treated mouse brains are reversed by FA-97, with the increased expression of HO-1, NQO-1, and nuclear Nrf2. In conclusion, FA-97 protects against oxidative stress-mediated neuronal cell apoptosis and SCOP-induced cognitive impairment by activating Nrf2/HO-1 signaling, which might be developed as a therapeutic drug for AD.

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