scholarly journals Hypericin-mediated sonodynamic therapy induces autophagy and decreases lipids in THP-1 macrophage by promoting ROS-dependent nuclear translocation of TFEB

2016 ◽  
Vol 7 (12) ◽  
pp. e2527-e2527 ◽  
Author(s):  
Xuesong Li ◽  
Xin Zhang ◽  
Longbin Zheng ◽  
Jiayuan Kou ◽  
Zhaoyu Zhong ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Lipid Uptake ◽  
Sonodynamic Therapy ◽  
Lipid Degradation ◽  
Lipid Catabolism ◽  
Lipid Efflux ◽  
Abca1 Expression ◽  
Transcription Factor Eb ◽  
Ros Scavenger ◽  
Cholesterol Transporters

Abstract Lipid catabolism disorder is the primary cause of atherosclerosis. Transcription factor EB (TFEB) prevents atherosclerosis by activating macrophage autophagy to promote lipid degradation. Hypericin-mediated sonodynamic therapy (HY-SDT) has been proved non-invasively inducing THP-1-derived macrophage apoptosis; however, it is unknown whether macrophage autophagy could be triggered by HY-SDT to influence cellular lipid catabolism via regulating TFEB. Here, we report that HY-SDT resulted in the time-dependent THP-1-derived macrophage autophagy activation through AMPK/AKT/mTOR pathway. Besides, TFEB nuclear translocation in macrophage was triggered by HY-SDT to promote autophagy activation and lysosome regeneration which enhanced lipid degradation in response to atherogenic lipid stressors. Moreover, following HY-SDT, the ABCA1 expression level was increased to promote lipid efflux in macrophage, and the expression levels of CD36 and SR-A were decreased to inhibit lipid uptake, both of which were prevented by TFEB knockdown. These results indicated that TFEB nuclear translocation activated by HY-SDT was not only the key regulator of autophagy activation and lysosome regeneration in macrophage to promote lipolysis, but also had a crucial role in reverse cholesterol transporters to decrease lipid uptake and increase lipid efflux. Reactive oxygen species (ROS) were adequately generated in macrophage by HY-SDT. Further, ROS scavenger N-acetyl-l-cysteine abolished HY-SDT-induced TFEB nuclear translocation and autophagy activation, implying that ROS were the primary upstream factors responsible for these effects during HY-SDT. In summary, our data indicate that HY-SDT decreases lipid content in macrophage by promoting ROS-dependent nuclear translocation of TFEB to influence consequent autophagy activation and cholesterol transporters. Thus, HY-SDT may be beneficial for atherosclerosis via TFEB regulation to ameliorate lipid overload in atherosclerotic plaques.

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.

Cetrimonium bromide promotes lipid clearance via TFEB-mediated autophagy-lysosome activation in hepatic cells

2021 ◽  
Author(s):  
Zhenxing Liu ◽  
Xu Wang ◽  
Zhichen Shi ◽  
Junting Xu ◽  
Jieru Lin ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Metabolic Disorders ◽  
Nuclear Translocation ◽  
Quaternary Ammonium Compound ◽  
Ammonium Compound ◽  
Hepatic Cells ◽  
Mtorc1 Signaling ◽  
Transcription Factor Eb ◽  
Potential Strategy ◽  
Cetrimonium Bromide

Autophagy plays a key role in the metabolism of macromolecules by the lysosomal degradative machinery. The transcription factor EB (TFEB) regulates autophagosome biogenesis and lysosome function, and promoting TFEB activity has emerged as a potential strategy for the treatment of metabolic disorders. Here, we describe that cetrimonium bromide (CTAB), a quaternary ammonium compound, promotes autophagy and lysosomal biogenesis by inducing the nuclear translocation of TFEB in hepatic cells. shRNA-mediated TFEB knockdown inhibits CTAB-induced autophagy and lysosomal biogenesis. Mechanistically, CTAB treatment inhibits the Akt-mTORC1 signaling pathway. Moreover, CTAB treatment markedly promotes lipid metabolism in both palmitate and oleate-treated HepG2 cells, and this promotion was attenuated by the depletion of TFEB. Altogether, our results indicate that CTAB activates the autophagy-lysosome pathway by inducing the nuclear translocation of TFEB via the inhibition of mTORC1 signaling. These results deepen our understanding of TFEB function and provide new insights into CTAB-mediated lipid metabolism.

scholarly journals Curcumin Analogue C1 Promotes Hex and Gal Recruitment to the Plasma Membrane via mTORC1-Independent TFEB Activation

2019 ◽  
Vol 20 (6) ◽  
pp. 1363 ◽  
Author(s):  
Alessandro Magini ◽  
Alice Polchi ◽  
Danila Di Meo ◽  
Sandra Buratta ◽  
Elisabetta Chiaradia ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Nuclear Translocation ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cell Line ◽  
Jurkat Cells ◽  
Lipid Microdomains ◽  
Curcumin Analogue ◽  
Transcription Factor Eb ◽  
Increased Activity

The monocarbonyl analogue of curcumin (1E,4E)-1,5-Bis(2-methoxyphenyl)penta-1,4-dien-3-one (C1) has been used as a specific activator of the master gene transcription factor EB (TFEB) to correlate the activation of this nuclear factor with the increased activity of lysosomal glycohydrolases and their recruitment to the cell surface. The presence of active lysosomal glycohydrolases associated with the lipid microdomains has been extensively demonstrated, and their role in glycosphingolipid (GSL) remodeling in both physiological and pathological conditions, such as neurodegenerative disorders, has been suggested. Here, we demonstrate that Jurkat cell stimulation elicits TFEB nuclear translocation and an increase of both the expression of hexosaminidase subunit beta (HEXB), hexosaminidase subunit alpha (HEXA), and galactosidase beta 1 (GLB1) genes, and the recruitment of β-hexosaminidase (Hex, EC 3.2.1.52) and β-galactosidase (Gal, EC 3.2.1.23) on lipid microdomains. Treatment of Jurkat cells with the curcumin analogue C1 also resulted in an increase of both lysosomal glycohydrolase activity and their targeting to the cell surface. Similar effects of C1 on lysosomal glycohydrolase expression and their recruitment to lipid microdomains was observed by treating the SH-SY5Y neuroblastoma cell line; the effects of C1 treatment were abolished by TFEB silencing. Together, these results clearly demonstrate the existence of a direct link between TFEB nuclear translocation and the transport of Hex and Gal from lysosomes to the plasma membrane.

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 Assessment on the oil accumulation by knockdown of triacylglycerol lipase in the oleaginous diatom Fistulifera solaris

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshiaki Maeda ◽  
Kahori Watanabe ◽  
Marshila Kaha ◽  
Yusuke Yabu ◽  
Tomoko Yoshino ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Positive Impact ◽  
Lipid Production ◽  
Single Type ◽  
Oil Accumulation ◽  
Triacylglycerol Lipase ◽  
Lipid Degradation ◽  
Lipid Catabolism ◽  
Conventional Culture ◽  
Growth System

AbstractMicroalgae are promising producers of biofuel due to higher accumulation of triacylglycerol (TAG). However, further improvement of the lipid metabolism is critical for feasible application of microalgae in industrial production of biofuel. Suppression of lipid degradation pathways is a promising way to remarkably increase the lipid production in model diatoms. In this study, we established an antisense-based knockdown (KD) technique in the marine oleaginous diatom, Fistulifera solaris. This species has a capability to accumulate high content of lipids. Tgl1 KD showed positive impact on cell growth and lipid accumulation in conventional culture in f/2 medium, resulting in higher oil contents compared to wild type strain. However, these impacts of Tgl1 KD were slight when the cells were subjected to the two-stage growth system. The Tgl1 KD resulted in slight change of fatty acid composition; increasing in C14:0, C16:0 and C16:1, and decreasing in C20:5. This study indicates that, although Tgl1 played a certain role in lipid degradation in F. solaris, suppression of only a single type of TAG lipase was not significantly effective to improve the lipid production. Comprehensive understanding of the lipid catabolism in this microalga is essential to further improve the lipid production.

scholarly journals Aggregatibacter actinomycetemcomitans Induces Autophagy in Human Junctional Epithelium Keratinocytes

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1221
Author(s):  
Emiliano Vicencio ◽  
Esteban M. Cordero ◽  
Bastián I. Cortés ◽  
Sebastián Palominos ◽  
Pedro Parra ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Close Association ◽  
Three Dimensional ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Host Cells ◽  
Junctional Epithelium ◽  
Main Site ◽  
Homeostatic Process ◽  
Transcription Factor Eb ◽  
Adverse Environmental Conditions

The adverse environmental conditions found in the periodontium during periodontitis pathogenesis stimulate local autophagy responses, mainly due to a continuous inflammatory response against the dysbiotic subgingival microbiome. The junctional epithelium represents the main site of the initial interaction between the host and the dysbiotic biofilm. Here, we investigated the role of autophagy in junctional epithelium keratinocytes (JEKs) in response to Aggregatibacter actinomycetemcomitans or its purified lipopolysaccharides (LPS). Immunofluorescence confocal analysis revealed an extensive nuclear translocation of transcription factor EB (TFEB) and consequently, an increase in autophagy markers and LC3-turnover assessed by immunoblotting and qRT-PCR. Correspondingly, challenged JEKs showed a punctuate cytosolic profile of LC3 protein contrasting with the diffuse distribution observed in untreated controls. Three-dimensional reconstructions of confocal images displayed a close association between intracellular bacteria and LC3-positive vesicles. Similarly, a close association between autophagic vesicles and the protein p62 was observed in challenged JEKs, indicating that p62 is the main adapter protein recruited during A. actinomycetemcomitans infection. Finally, the pharmacological inhibition of autophagy significantly increased the number of bacteria-infected cells as well as their death, similar to treatment with LPS. Our results indicate that A. actinomycetemcomitans infection induces autophagy in JEKs, and this homeostatic process has a cytoprotective effect on the host cells during the early stages of infection.

scholarly journals The Glucosylceramide Synthase Inhibitor PDMP Causes Lysosomal Lipid Accumulation and mTOR Inactivation

2021 ◽  
Vol 22 (13) ◽  
pp. 7065
Author(s):  
Pia Hartwig ◽  
Doris Höglinger
Keyword(s):  
Lipid Accumulation ◽  
Nuclear Translocation ◽  
Dependent Manner ◽  
Acute Effects ◽  
Glucosylceramide Synthase ◽  
Anti Cancer ◽  
Transcription Factor Eb ◽  
Lysobisphosphatidic Acid ◽  
Synthase Inhibitor ◽  
Target Transcription Factor

For many years, the biology of glycosphingolipids was elucidated with the help of glucosylceramide synthase (GCS) inhibitors such as 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP). Additionally, PDMP gained interest because of its chemosensitizing effects. Several studies have successfully combined PDMP and anti-cancer drugs in the context of cancer therapy. However, the mechanism of action of PDMP is not fully understood and seems to go beyond glycolipid inhibition. Here, we used a functionalized sphingosine analogue (pacSph) to investigate the acute effects of PDMP on cellular sphingolipid distribution and found that PDMP, but not other GCS inhibitors, such as ND-DNJ (also called Miglustat), induced sphingolipid accumulation in lysosomes. This effect could be connected to defective export from lysosome, as monitored by the prolonged lysosomal staining of sphingolipids as well as by a delay in the metabolic conversion of the pacSph precursor. Additionally, other lipids such as lysobisphosphatidic acid (LBPA) and cholesterol were enriched in lysosomes upon PDMP treatment in a time-dependent manner. We could further correlate early LBPA enrichment with dissociation of the mechanistic target of rapamycin (mTOR) from lysosomes followed by nuclear translocation of its downtream target, transcription factor EB (TFEB). Altogether, we report here a timeline of lysosomal lipid accumulation events and mTOR inactivation arising from PDMP treatment.

scholarly journals Bisphenol a Induces Autophagy Defects and AIF-Dependent Apoptosis via HO-1 and AMPK to Degenerate N2a Neurons

2021 ◽  
Vol 22 (20) ◽  
pp. 10948
Author(s):  
Ching-Tien Lee ◽  
Cheng-Fang Hsieh ◽  
Jiz-Yuh Wang
Keyword(s):  
Bisphenol A ◽  
Nuclear Translocation ◽  
Neuronal Degeneration ◽  
Epidemiological Studies ◽  
Oxygen Free Radical ◽  
Neuronal Viability ◽  
Brain Degeneration ◽  
Ros Scavenger ◽  
Apoptosis Inducing Factor ◽  
Amp Activated Protein Kinase

Bisphenol A (BPA) is an environmental contaminant widely suspected to be a neurological toxicant. Epidemiological studies have demonstrated close links between BPA exposure, pathogenetic brain degeneration, and altered neurobehaviors, considering BPA a risk factor for cognitive dysfunction. However, the mechanisms of BPA resulting in neurodegeneration remain unclear. Herein, cultured N2a neurons were subjected to BPA treatment, and neurotoxicity was assessed using neuronal viability and differentiation assays. Signaling cascades related to cellular self-degradation were also evaluated. BPA decreased cell viability and axon outgrowth (e.g., by down-regulating MAP2 and GAP43), thus confirming its role as a neurotoxicant. BPA induced neurotoxicity by down-regulating Bcl-2 and initiating apoptosis and autophagy flux inhibition (featured by nuclear translocation of apoptosis-inducing factor (AIF), light chain 3B (LC3B) aggregation, and p62 accumulation). Both heme oxygenase (HO)-1 and AMP-activated protein kinase (AMPK) up-regulated/activated by BPA mediated the molecular signalings involved in apoptosis and autophagy. HO-1 inhibition or AIF silencing effectively reduced BPA-induced neuronal death. Although BPA elicited intracellular oxygen free radical production, ROS scavenger NAC exerted no effect against BPA insults. These results suggest that BPA induces N2a neurotoxicity characterized by AIF-dependent apoptosis and p62-related autophagy defects via HO-1 up-regulation and AMPK activation, thereby resulting in neuronal degeneration.

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