Autophagy prevents autophagic cell death in Tetrahymena in response to oxidative stress

Autophagy is a major cellular pathway used to degrade long-lived proteins or organelles that may be damaged due to increased reactive oxygen species（ROS） generated by cellular stress. Autophagy typically enhances cell survival, but it may also act to promote cell death under certain conditions. The mechanism underlying this paradox, however, remains unclear. We showed that Tetrahymena cells exerted increased membranebound vacuoles characteristic of autophagy followed by autophagic cell death（referred to as cell death with autophagy） after exposure to hydrogen peroxide. Inhibition of autophagy by chloroquine or 3-methyladenine significantly augmented autophagic cell death induced by hydrogen peroxide. Blockage of the mitochondrial electron transport chain or starvation triggered activation of autophagy followed by cell death by inducing the production of ROS due to the loss of mitochondrial membrane potential. This indicated a regulatory role of mitochondrial ROS in programming autophagy and autophagic cell death in Tetrahymena. Importantly, suppression of autophagy enhanced autophagic cell death in Tetrahymena in response to elevated ROS production from starvation, and this was reversed by antioxidants. Therefore, our results suggest that autophagy was activated upon oxidative stress to prevent the initiation of autophagic cell death in Tetrahymena until the accumulation of ROS passed the point of no return, leading to delayed cell death in Tetrahymena.

Autophagic cell death induced by reactive oxygen species is involved in hyperthermic sensitization to ionizing radiation in human hepatocellular carcinoma cells

AIM To investigate whether autophagic cell death is involved in hyperthermic sensitization to ionizing radiation in human hepatocellular carcinoma cells, and to explore the underlying mechanism.METHODS Human hepatocellular carcinoma cells were treated with hyperthermia and ionizing radiation. MTT and clonogenic assays were performed to determine cell survival. Cell autophagy was detected using acridine orange staining and flow cytometric analysis, and the expression of autophagy-associated proteins, LC3 and p62, was determined by Western blot analysis. Intracellular reactive oxygen species(ROS) were quantified using the fluorescent probe DCFH-DA.RESULTS Treatment with hyperthermia and ionizing radiation significantly decreased cell viability and surviving fraction as compared with hyperthermia or ionizing radiation alone. Cell autophagy was significantly increased after ionizing radiation combined with hyperthermia treatment, as evidenced by increased formation of acidic vesicular organelles, increased expression of LC3 II and decreased expression of p62. Intracellular ROS were also increased after combined treatment with hyperthermia and ionizing radiation. Pretreatment with N-acetylcysteine, an ROS scavenger, markedly inhibited the cytotoxicity and cell autophagy induced by hyperthermia and ionizing radiation.CONCLUSION Autophagic cell death is involved in hyperthermic sensitization of cancer cells to ionizing radiation, and its induction may be due to the increased intracellular ROS.

Retinoic acid alleviates rotavirus-induced intestinal damage by regulating redox homeostasis and autophagic flux in piglets

Rotaviruses(RV)are a major cause of severe gastroenteritis,particularly in neonatal piglets.Despite the availability of effective vaccines,the development of antiviral therapies for RV remains an ongoing challenge.Retinoic acid(RA),a metabolite of vitamin A,has been shown to have anti-oxidative and antiviral properties.However,the mechanism by which RA exerts its intestinal-protective and antiviral effects on RV infection is not fully understood.The study investigates the effects of RA supplementation in Duroc×Landrace×Yorkshire(DLY)piglets challenged with RV.Thirty-six DLY piglets were assigned into six treatments,including a control group,RA treatment group with two concentration gradients(5and 15 mg/d),RV treatment group,and RV treatment group with the addition of different concentration gradients of RA(5 and 15 mg/d).Our study revealed that RV infection led to extensive intestinal architecture damage,which was mitigated by RA treatment at lower concentrations by increasing the villus height and villus height/crypt depth ratio(P<0.05),enhancing intestinal stem cell signaling and promoting intestinal barrier functions.In addition,15 mg/d RA supplementation significantly increased NRF2 and HO-1 protein expression(P<0.05)and GSH content(P<0.05),indicating that RA supplementation can enhance anti-oxidative signaling and redox homeostasis after RV challenge.Additionally,the research demonstrated that RA exerts a dual impact on the regulation of autophagy,both stimulating the initiation of autophagy and hindering the flow of autophagic flux.Through the modulation of autophagic flux,RA influence the progression of RV infection.These findings provide new insights into the regulation of redox hemostasis and autophagy by RA and its potential therapeutic application in RV infection.

Role of lipids in the control of autophagy and primary cilium signaling in neurons

The brain is,after the adipose tissue,the organ with the greatest amount of lipids and diversity in their composition in the human body.In neurons,lipids are involved in signaling pathways controlling autophagy,a lysosome-dependent catabolic process essential for the maintenance of neuronal homeostasis and the function of the primary cilium,a cellular antenna that acts as a communication hub that transfers extracellular signals into intracellular responses required for neurogenesis and brain development.A crosstalk between primary cilia and autophagy has been established;however,its role in the control of neuronal activity and homeostasis is barely known.In this review,we briefly discuss the current knowledge regarding the role of autophagy and the primary cilium in neurons.Then we review the recent literature about specific lipid subclasses in the regulation of autophagy,in the control of primary cilium structure and its dependent cellular signaling in physiological and pathological conditions,specifically focusing on neurons,an area of research that could have major implications in neurodevelopment,energy homeostasis,and neurodegeneration.

From macroautophagy to mitophagy:Unveiling the hidden role of mitophagy in gastrointestinal disorders

In this editorial,we comment on an article titled“Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases”,which was published in a recent issue of the World Journal of Gastroenterology.We focused on the statement that“autophagy is closely related to the digestion,secretion,and regeneration of gastrointestinal cells”.With advancing research,autophagy,and particularly the pivotal role of the macroautophagy in maintaining cellular equilibrium and stress response in the gastrointestinal system,has garnered extensive study.However,the significance of mitophagy,a unique selective autophagy pathway with ubiquitin-dependent and independent variants,should not be overlooked.In recent decades,mitophagy has been shown to be closely related to the occurrence and development of gastrointestinal diseases,especially inflammatory bowel disease,gastric cancer,and colorectal cancer.The interplay between mitophagy and mitochondrial quality control is crucial for elucidating disease mechanisms,as well as for the development of novel treatment strategies.Exploring the pathogenesis behind gastrointestinal diseases and providing individualized and efficient treatment for patients are subjects we have been exploring.This article reviews the potential mechanism of mitophagy in gastrointestinal diseases with the hope of providing new ideas for diagnosis and treatment.

Autophagic activity in neuronal cell death

As post-mitotic cells with great energy demands, neurons depend upon the homeostatic and waste-recycling functions provided by autophagy. In addition, autophagy also promotes survival during periods of harsh stress and targets aggregate-prone proteins associated with neurodegeneration for degradation. Despite this, autophagy has also been controversially described as a mechanism of programmed cell death. Instances of autophagic cell death are typically associated with elevated numbers of cytoplasmic autophagosomes, which have been assumed to lead to excessive degradation of cellular components. Due to the high activity and reliance on autophagy in neurons, these cells may be particularly susceptible to autophagic death. In this review, we summarize and assess current evidence in support of autophagic cell death in neurons, as well as how the dysregulation of autophagy commonly seen in neurodegeneration can contribute to neuron loss. From here, we discuss potential treatment strategies relevant to such cell-death pathways.

Neuroprotective Autophagic Flux Induced by Hyperbaric Oxygen Preconditioning is Mediated by Cystatin C

We have previously reported that Cystatin C(CysC) is a pivotal mediator in the neuroprotection induced by hyperbaric oxygen(HBO) preconditioning; however,the underlying mechanism and how CysC changes after stroke are not clear. In the present study, we demonstrated that CysC expression was elevated as early as 3 h after reperfusion, and this was further enhanced by HBO preconditioning. Concurrently, LC3-II and Beclin-1, two positive-markers for autophagy induction, exhibited increases similar to CysC, while knockdown of CysC blocked these elevations. As a marker of autophagy inhibition, p62 was downregulated by HBO preconditioning and this was blocked by CysC knockdown. Besides, the beneficial effects of preserving lysosomal membrane integrity and enhancing autolysosome formation induced by HBO preconditioning were abolished in CysC-/-rats.Furthermore, we demonstrated that exogenous CysC reduced the neurological deficits and infarct volume after brain ischemic injury, while 3-methyladenine partially reversed this neuroprotection. In the present study, we showed that CysC is biochemically and morphologically essential for promoting autophagic flux, and highlighted the translational potential of HBO preconditioning and CysC for stroke treatment.

Actively priming autophagic cell death with novel transferrin receptor-targeted nanomedicine for synergistic chemotherapy against breast cancer

Recently, considerable attention in the field of cancer therapy has been focused on the mammalian rapamycin target(m TOR), inhibition of which could result in autophagic cell death(ACD). Though novel combination chemotherapy of autophagy inducers with chemotherapeutic agents is extensively investigated, nanomedicine-based combination therapy for ACD remains in infancy. In attempt to actively trigger ACD for synergistic chemotherapy, here we incorporated autophagy inducer rapamycin(RAP) into 7 pep-modified PEG-DSPE polymer micelles(7 pep-M-RAP) to specifically target and efficiently priming ACD of MCF-7 human breast cancer cells with high expression of transferrin receptor(Tf R). Cytotoxic paclitaxel(PTX)-loaded micelle(7 pep-M-PTX) was regarded as chemotherapeutic drug model. We discovered that with superior intracellular uptake in vitro and more tumor accumulation of micelles in vivo, 7 pep-M-RAP exhibited excellent autophagy induction and synergistic antitumor efficacy with 7 pep-M-PTX. Mechanism study further revealed that 7 pep-M-RAP and 7 pep-MPTX used in combination provided enhanced efficacy through induction of both apoptosis-and mitochondria-associated autophagic cell death. Together, our findings suggested that the targeted excess autophagy may provide a rational strategy to improve therapeutic outcome of breast cancer, and simultaneous induction of ACD and apoptosis may be a promising anticancer modality.

Multi-omics approaches identify SF3B3 and SIRT3 as candidate autophagic regulators and druggable targets in invasive breast carcinoma

Autophagy is a critical cellular homeostatic mechanism,and its dysfunction is linked to invasive breast carcinoma(BRCA).Recently,several omics methods have been applied to explore autophagic regulators in BRCA;however,more reliable and robust approaches for identifying crucial regulators and druggable targets remain to be discovered.Thus,we report here the results of multi-omics approaches to identify potential autophagic regulators in BRCA,including gene expression(EXP),DNA methylation(MET)and copy number alterations(CNAs)from The Cancer Genome Atlas(TCGA).Newly identified candidate genes,such as SF3 B3,TRAPPC10,SIRT3,MTERFD1,and FBXO5,were confirmed to be involved in the positive or negative regulation of autophagy in BRCA.SF3 B3 was identified firstly as a negative autophagic regulator,and siRNA/shRNA-SF3 B3 were shown to induce autophagyassociated cell death in in vitro and in vivo breast cancer models.Moreover,a novel small-molecule activator of SIRT3,1-methylbenzylamino amiodarone,was discovered to induce autophagy in vitro and in vivo.Together,these results provide multi-omics approaches to identify some key candidate autophagic regulators,such as the negative regulator SF3 B3 and positive regulator SIRT3 in BRCA,and highlight SF3 B3 and SIRT3 as new druggable targets that could be used to fill the gap between autophagy and cancer drug development.

Autophagic dysfunction of β cell dysfunction in type 2 diabetes,a double-edged sword

Diabetes is an age-related disease,most of which is type 2 diabetes,and islet β cell dysfunction and insulin resistance are the main mechanisms of type 2 diabetes.Recent studies have revealed that autophagy plays an important role in maintaining the structure and func-tion of islet beta cells and inhibiting insulin resistance and apoptosis induced by oxidative stress.In this review,we discussed the positive and negative effects of autophagy and its dysfunction on type 2 diabetes mellitus,which is the so-called double-edged sword,analysed its possible mechanism,and identifed possible research hot spots.

Curcumin-induced cell death depends on the level of autophagic flux in A172 and U87MG human glioblastoma cells

Glioblastoma is the deadliest neoplasm with the worst 5-year survival rate among all human cancers.Autophagy promotes autophagic cell death or blocks the induction of apoptosis in eukaryotic cells.Here,we investigated whether varying levels of autophagic flux in glioblastoma lead to different efficacies of curcumin treatment using U87 MG and A172 human glioblastoma cells.The number of LC3 puncta,the number of cells with LC3 puncta and the level of LC3 Ⅱ,Atg5 and Atg7 protein were higher in U87 MG cells compared with A172 cells.When the cells were incubated with curcumin for 24 or 48 h,the percentage of cell death was higher in A172 cells compared with U87 MG cells.Although the level of LC3 was lower,that of curcumin-induced LC3 was higher,in A172 cells than in U87 MG cells.The relative increases in cell death and LC3-mediated autophagy were greater under serum starvation in A172 cells compared with U87 MG cells.Curcumin-induced A172 cell death was reduced by serum starvation.When both types of cells were transfected with LC3-GFP,the percentage of cell death was higher in A172 cells than that in U87 MG cells.Taken together,the data demonstrate that curcumin-mediated tumor cell death is regulated by the basal level of autophagic flux in different glioblastoma cells.This suggests that prior to the use of various curcumin therapeutics,the level of basal or induced autophagic flux should be carefully examined in tumor cells for the best efficacy.

Regulation of autophagic flux by CHIP

Autophagy is a major degradation system which processes substrates through the steps of auto- phagosome formation, autophagosome-lysosome fusion, and substrate degradation. Aberrant autophagic flux is present in many pathological conditions including neurodegeneration and tumors. CHIP/STUB1, an E3 ligase, plays an important role in neurodegeneration. In this study, we identified the regulation of autophagic flux by CHIP （carboxy-terminus of HscT0-interacting protein）. Knockdown of CHIP induced autophagosome formation through increasing the PTEN protein level and decreasing the AKT/mTOR activity as well as decreasing phosphorylation of ULK1 on Ser757. However, degradation of the autophagic substrate p62 was disturbed by knockdown of CHIP, suggesting an abnormality of autophagic flux. Furthermore, knockdown of CHIP increased the susceptibility of cells to autophagic cell death induced by bafilomycin AI. Thus, our data suggest that CHIP plays roles in the regulation of autophagic flux.

Modulating autophagic flux via ROS-responsive targeted micelles to restore neuronal proteostasis in Alzheimer’s disease

Compromised autophagy and defective lysosomal clearance significantly contribute to impaired neuronal proteostasis,which represents a hallmark of Alzheimer’s disease(AD)and other age-related neurodegenerative disorders.Growing evidence has implicated that modulating autophagic flux,instead of inducing autophagosome formation alone,would be more reliable to rescue neuronal proteostasis.Concurrently,selectively enhancing drug concentrations in the leision areas,instead of the whole brain,will maximize therapeutic efficacy while reduing non-selective autophagy induction.Herein,we design a ROS-responsive targeted micelle system(TT-NM/Rapa)to enhance the delivery efficiency of rapamycin to neurons in AD lesions guided by the fusion peptide TPL,and facilitate its intracellular release via ROS-mediated disassembly of micelles,thereby maximizing autophagic flux modulating efficacy of rapamycin in neurons.Consequently,it promotes the efficient clearance of intracellular neurotoxic proteins,β-amyloid and hyperphosphorylated tau proteins,and ameliorates memory defects and neuronal damage in 3×Tg-AD transgenic mice.Our studies demonstrate a promising strategy to restore autophagic flux and improve neuronal proteostasis by rationally-engineered nano-systems for delaying the progression of AD.

Nanosize aminated fullerene for autophagic flux activation and G0/G1 phase arrest in cancer cells via post-transcriptional regulation

Functional fullerene derivatives exhibit special inhibitory effects on tumor progress and metastasis via diverse tumor microenvironment regulations,while the elusive molecular mechanisms hinder their clinical transformation.Herein,it is initially revealed that nanosize aminated fullerene(C_(70)-EDA)can activate autophagic flux,induce G0/G1 cell cycle arrest to abrogate cancer cell proliferation,and significantly inhibit tumor growth in vivo.Mechanismly,C_(70)-EDA promotes the expression of cathepsin D involved in autophagic activation via post-transcriptional regulation,attributing to the interaction with a panel of RNA binding proteins.The accumulation of cathepsin D induces the autophagic degradation of cyclin D1,which arouses G0/G1 phase arrest.This work unveils the fantastic anti-tumor activity of aminated fullerene,elucidates the molecular mechanism,and provides a new strategy for the antineoplastic drug development on functional fullerenes.

Pterostilbene attenuates intrauterine growth retardation-induced colon inflamm tion in piglets by modulating endoplasmic reticulum stress and autophagy

Background:Endoplasmic reticulum(ER)stress and autophagy are implicated in the pathophysiology of intestinal inflammation;however,their roles in intrauterine growth retardation(IUGR)-induced colon inflammation are unclear.This study explored the protective effects of natural stilbene pterostilbene on colon inflammation using the IUGR piglets and the tumor necrosis factor alpha(TNF-α)-treated human colonic epithelial cells(Caco-2)by targeting ER stress and autophagy.Results:Both the IUGR colon and the TNF-α-treated Caco-2 cells exhibited inflammatory responses,ER stress,and impaired autophagic flux(P<0.05).The ER stress inducer tunicamycin and the autophagy inhibitor 3-methyladenine further augmented inflammatory responses and apoptosis in the TNF-α-treated Caco-2 cells(P<0.05).Conversely,pterostilbene inhibited ER stress and restored autophagic flux in the IUGR colon and the TNF-α-treated cells(P<0.05).Pterostilbene also prevented the release of inflammatory cytokines and nuclear translocation of nuclear factor kappa B p65,reduced intestinal permeability and cell apoptosis,and facilitated the expression of intestinal tight junction proteins in the IUGR colon and the TNF-α-treated cells(P<0.05).Importantly,treatment with tunicamycin or autophagosome-lysosome binding inhibitor chloroquine blocked the positive effects of pterostilbene on inflammatory response,cell apoptosis,and intestinal barrier function in the TNF-α-exposed Caco-2 cells(P<0.05).Conclusion:Pterostilbene mitigates ER stress and promotes autophagic flux,thereby improving colon inflammation and barrier dysfunction in the IUGR piglets and the TNF-α-treated Caco-2 cells.

Suberoylanilide hydroxamic acid upregulates reticulophagy receptor expression and promotes cell death in hepatocellular carcinoma cells

BACKGROUND Hepatocellular carcinoma(HCC)is a common clinical condition with a poor prognosis and few effective treatment options.Potent anticancer agents for treating HCC must be identified.Epigenetics plays an essential role in HCC tumorigenesis.Suberoylanilide hydroxamic acid(SAHA),the most common histone deacetylase inhibitor agent,triggers many forms of cell death in HCC.However,the underlying mechanism of action remains unclear.Family with sequence similarity 134 member B(FAM134B)-induced reticulophagy,a selective autophagic pathway,participates in the decision of cell fate and exhibits anticancer activity.This study focused on the relationship between FAM134B-induced reticulophagy and SAHA-mediated cell death.AIM To elucidate potential roles and underlying molecular mechanisms of reticulophagy in SAHA-induced HCC cell death.METHODS The viability,apoptosis,cell cycle,migration,and invasion of SAHA-treated Huh7 and MHCC97L cells were measured.Proteins related to the reticulophagy pathway,mitochondria-endoplasmic reticulum(ER)contact sites,intrinsic mitochondrial apoptosis,and histone acetylation were quantified using western blotting.ER and lysosome colocalization,and mitochondrial Ca^(2+)levels were characterized via confocal microscopy.The level of cell death was evaluated through Hoechst 33342 staining and propidium iodide colocalization.Chromatin immunoprecipitation was used to verify histone H4 lysine-16 acetylation in the FAM134B promoter region.RESULTS After SAHA treatment,the proliferation of Huh7 and MHCC97L cells was significantly inhibited,and the migration and invasion abilities were greatly blocked in vitro.This promoted apoptosis and caused G1 phase cells to increase in a concentration-dependent manner.Following treatment with SAHA,ER-phagy was activated,thereby triggering autophagy-mediated cell death of HCC cells in vitro.Western blotting and chromatin immunoprecipitation assays confirmed that SAHA regulated FAM134B expression by enhancing the histone H4 lysine-16 acetylation in the FAM134B promoter region.Further,SAHA disturbed the Ca^(2+)homeostasis and upregulated the level of autocrine motility factor receptor and proteins related to mitochondria-endoplasmic reticulum contact sites in HCC cells.Additionally,SAHA decreased the mitochondrial membrane potential levels,thereby accelerating the activation of the reticulophagy-mediated mitochondrial apoptosis pathway and promoting HCC cell death in vitro.CONCLUSION SAHA stimulates FAM134B-mediated ER-phagy to synergistically enhance the mitochondrial apoptotic pathway,thereby enhancing HCC cell death.

Neuronal autophagy aggravates microglial inflammatory injury by downregulating CX3CL1/fractalkine after ischemic stroke

Ischemic stroke often induces excessive neuronal autophagy, resulting in brain damage; meanwhile, inflammatory responses stimulated by ischemia exacerbate neural injury. However, interactions between neuronal autophagy and microglial inflammation following ischemic stroke are poorly understood. CX3CL1/fractalkine, a membrane-bound chemokine expressed on neurons, can suppress microglial inflammation by binding to its receptor CX3CR1 on microglia. In the present study, to investigate whether autophagy could alter CX3CL1 expression on neurons and consequently change microglial inflammatory activity, middle cerebral artery occlusion(MCAO) was established in Sprague-Dawley rats to model ischemic stroke, and tissues from the ischemic penumbra were obtained to evaluate autophagy level and microglial inflammatory activity. MCAO rats were administered 3-methyladenine(autophagy inhibitor) or Tat-Beclin 1(autophagy inducer). Western blot assays were conducted to quantify expression of Beclin-1, nuclear factor kappa Bp65(NF-κB), light chain 3B(LC3B), and CX3CL1 in ischemic penumbra. Moreover, immunofluorescence staining was performed to quantify numbers of LC3B-, CX3CL1-, and Iba-1-positive cells in ischemic penumbra. In addition, enzyme linked immunosorbent assays were utilized to analyze concentrations of tumor necrosis factor alpha(TNF-α), interleukin 6(IL-6), interleukin 1 beta(IL-1β), and prostaglandin E2(PGE2). A dry/wet weight method was used to detect brain water content, while 2,3,5,-triphenyltetrazolium chloride staining was utilized to measure infarct volume. The results demonstrated that autophagy signaling(Beclin-1 and LC3B expression) in penumbra was prominently activated by MCAO, while CX3CL1 expression on autophagic neurons was significantly reduced and microglial inflammation was markedly activated. However, after inhibition of autophagy signaling with 3-methyladenine, CX3CL1 expression on neurons was obviously increased, whereas Iba-1 and NF-κB expression was downregulated; TNF-α, IL-6, IL-1β, and PGE2 levels were decreased; and cerebral edema was obviously mitigated. In contrast, after treatment with the autophagy inducer Tat-Beclin 1, CX3CL1 expression on neurons was further reduced; Iba-1 and NF-κB expression was increased; TNF-α, IL-6, IL-1β, and PGE2 levels were enhanced; and cerebral edema was aggravated. Our study suggests that ischemia-induced neuronal autophagy facilitates microglial inflammatory injury after ischemic stroke, and the efficacy of this process may be associated with downregulated CX3CL1 expression on autophagic neurons.

Autophagy activation by Jiang Zhi Granule protects against metabolic stress-induced hepatocyte injury

AIM To elucidate the potential role of autophagy and the protective effects of Jiang Zhi Granule(JZG) in metabolic stress-induced hepatocyte injury.METHODS An in vitro and in vivo approach was used in this study. Hep G2 cells were incubated in culture medium containing palmitate(PA; 0, 0.1, 0.2, 0.3, 0.4 or 0.5 mmol/L) and treated with or without JZG(100 μg/m L) for 24 h or 48 h, and the progression of autophagy was visualized by stable fluorescence-expressing cell lines LC3 and p62. Western blot analyses were performed to examine the expression of LC3-Ⅱ/LC3-Ⅰ, p62, m TOR and PI3 K, while mitochondrial integrity and oxidative stress were observed by fluorescence staining of JC-1 and reactive oxygen species. C57 BL/6 mice were divided into three groups: control group(n = 10), high fat(HF) group(n = 13) and JZG group(n = 13); and, histological staining was carried out to detect inflammation and lipid content in the liver.RESULTS The cell trauma induced by PA was aggravated in a dose-and time-dependent manner, and hepatic function was improved by JZG. PA had dual effects on autophagy by activating autophagy induction and blocking autophagic flux. The PI3 K-AKT-m TOR signaling pathway and the fusion of isolated hepatic autophagosomes and lysosomes were critically involved in this process. JZG activated autophagy progression by either induction of autophagosomes or co-localization of autophagosomes and lysosomes as well as degradation of autolysosomes to protect against PA-induced hepatocyte injury, and protected mitochondrial integrity against oxidative stress in PA-induced mitochondrial dysfunction. In addition, JZG ameliorated lipid droplets and inflammation induced by HF diet in vivo, leading to improved metabolic disorder and associated liver injury in a mouse model of non-alcoholic fatty liver disease(NAFLD).CONCLUSION Metabolic stress-induced hepatocyte injury exhibited dual effects on autophagy and JZG activated the entire process, resulting in beneficial effects in NAFLD.

DJ-1 Activation Raf/ERK Pathways Promotes Autophagy Maturation of PC-12 Cells

Park 7 gene encodes a conserved protein called DJ-1 protein, which involves autophagy stress, but the mechanism is unclear. Therefore, it is necessary to explore the mechanism of DJ-1 regulation PC-12 autophagical stress. Using CRISPR/Cas9 technique to construct DJ-1 knockout PC-12 cell lines, we culture wild-type and DJ-1 knockout PC-12 cell lines, establish oxidative stress cell model by MPP+, and divide them into wild-type control group (WT), wild-type intervention group (WT + MPP+), DJ-1 knockout control group (KO) and DJ-1 knockout intervention group (KO + MPP+), and explore the role of DJ-1 in regulating neuronal autophagy stress by cell viability assay, immunofluorescence, confocal, western blotting and electron microscopy. The results show that the growth ability of DJ-1 knockout cells is inferior to that of normal cells, and DJ-1 knockout cells are more sensitive to oxidative stress and more vulnerable to damage than wild-type cells. Exposing to MPP+, DJ-1 proteins undergo oxidative responses at Cys-106 sites, while DJ-1 knockout PC-12 cells do not show similar responses. The wild-type PC-12 cells have the confocal in both anti-oxidant DJ-1 antibody and anti-C-Raf phosphorylation antibody. The activated DJ-1 induces the phosphorylation of C-Raf at Ser338 sites to activate directly C-Raf, and subsequently activates ERK1/2 signaling pathways to antagonize MPP+-induced neurotoxicity. Lack of DJ-1, oxidative stress can not promote C-Raf activation. Although the phosphorylation level of cell ERK is also increased, the increase of intranucleus pERK is not obvious. Wild type and DJ-1 knockout PC-12 cells can produce autophagical stress in the face of oxidative stress, but the proportion of autophagolysosomes produced in wild type PC-12 cells is larger than that in DJ-1 knockout cells. PD98059 can reduce autophagy stress in the state of oxidative stress in wild-type PC-12 cells, and the number of autophagolysosomes is similarly reduced, while sorafenib decreased slightly DJ-1 the autophagical stress, and the proportion of autophagolysosomes decreased more. Therefore, we can infer that activated DJ-1 directly phosphorylates C-Raf at Ser-338 sites, then activating C-Raf, subsequent activation of the MEK/ERK pathway. DJ-1 promotes autophagy maturation through the C-Raf/ERK pathway, thereby improving cell survival.

Hernandezine promotes cancer cell apoptosis and disrupts the lysosomal acidic environment and cathepsin D maturation

Hernandezine(Her),a bisbenzylisoquinoline alkaloid extracted from Thalictrum flavum,is recognized for its range of biological activities inherent to this herbal medicine.Despite its notable properties,the anti-cancer effects of Her have remained largely unexplored.In this study,we elucidated that Her significantly induced cytotoxicity in cancer cells through the activation of apoptosis and necroptosis mechanisms.Furthermore,Her triggered autophagosome formation by activating the AMPK and ATG5 conjugation systems,leading to LC3 lipidation.Our findings revealed that Her caused damage to the mitochondrial membrane,with the damaged mitochondria undergoing mitophagy,as evidenced by the elevated expression of mitophagy markers.Conversely,Her disrupted autophagic flux,demonstrated by the upregulation of p62 and accumulation of autolysosomes,as observed in the RFP-GFP-LC3 reporter assay.Initially,we determined that Her did not prevent the fusion of autophagosomes and lysosomes.However,it inhibited the maturation of cathepsin D and increased lysosomal pH,indicating an impairment of lysosomal function.The use of the early-stage autophagy inhibitor,3-methyladenine(3-MA),did not suppress LC3II,suggesting that Her also induces noncanonical autophagy in autophagosome formation.The application of Bafilomycin A1,an inhibitor of noncanonical autophagy,diminished the recruitment of ATG16L1 and the accumulation of LC3II by Her,thereby augmenting Her-induced cell death.These observations imply that while autophagy initially plays a protective role,the disruption of the autophagic process by Her promotes programmed cell death.This study provides the first evidence of Her’s dual role in inducing apoptosis and necroptosis while also initiating and subsequently impairing autophagy to promote apoptotic cell death.These insights contribute to a deeper understanding of the mechanisms underlying programmed cell death,offering potential avenues for enhancing cancer prevention and therapeutic strategies.