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Parkinson's disease (PD) is a complex neurological disorder characterized by motor and nonmotor features. Although some drugs have been developed for the therapy of PD in a clinical setting, they only alleviate the clinical symptoms and have yet to show a cure. In this study, by employing the C. elegans model of PD, we found that ferulic acid (FA) significantly inhibited α -synuclein accumulation and improved dyskinesia in NL5901 worms. Meanwhile, FA remarkably decreased the degeneration of dopaminergic (DA) neurons, improved the food-sensing behavior, and reduced the level of reactive oxygen species (ROS) in 6-OHDA-induced BZ555 worms. The mechanistic study discovered that FA could activate autophagy in C. elegans , while the knockdown of 3 key autophagy-related genes significantly revoked the neuroprotective effects of FA in α -synuclein- and 6-OHDA-induced C. elegans models of PD, demonstrating that FA exerts an anti-PD effect via autophagy induction in C. elegans . Furthermore, we found that FA could reduce 6-OHDA- or H 2 O 2 -induced cell death and apoptosis in PC-12 cells. Moreover, FA was able to induce autophagy in stable GFP-RFP-LC3 U87 cells and PC-12 cells, while bafilomycin A1 (Baf, an autophagy inhibitor) partly eliminated the protective effects of FA against 6-OHDA- and H 2 O 2 -induced cell death and ROS production in PC-12 cells, further confirming that FA exerts an anti-PD effect via autophagy induction in vitro. Collectively, our study provides novel insights for FA as a potent autophagy enhancer to effectively prevent neurodegenerative diseases such as PD in the future., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Tao Long et al.)

Blood-brain barrier (BBB) dysfunction has been implicated in Alzheimer's disease (AD) and is closely linked to the release of proinflammatory cytokines in brain capillary endothelial cells. We have previously reported that lychee seed polyphenols (LSP) exerted anti-neuroinflammatory effect. In this study, we aimed to explore the protective effect of LSP on BBB integrity. The monolayer permeability of bEnd.3 cells, and the mRNA level and protein expression of tight junction proteins (TJs), including Claudin 5, Occludin, and ZO-1, were examined. In addition, the inhibition of Aβ(25-35)-induced NLRP3 inflammasome activation, and the autophagy induced by LSP were investigated by detecting the expression of NLRP3, caspase-1, ASC, LC3, AMPK, mTOR, and ULK1. Furthermore, the cognitive function and the expression of TJs, NLRP3, caspase-1, IL-1β, and p62 were determined in APP/PS1 mice. The results showed that LSP significantly decreased the monolayer permeability and inhibited the NLRP3 inflammasome in Aβ(25-35)-induced bEnd3 cells. In addition, LSP induced autophagy via the AMPK/mTOR/ULK1 pathway in bEnd.3 cells, and improved the spatial learning and memory function, increased the TJs expression, and inhibited the expression of NLRP3, caspase-1, IL-1β, and p62 in APP/PS1 mice. Therefore, LSP protects BBB integrity in AD through inhibiting Aβ(25-35)-induced NLRP3 inflammasome activation via the AMPK/mTOR/ULK1-mediated autophagy., (© 2020 John Wiley & Sons Ltd.)

Necroptosis is crucially involved in severe cardiac pathological conditions. However, whether necroptosis contributes to age-related intolerance to ischemia/reperfusion (I/R) injury remains elusive. In addition, metformin as a potential anti-aging related injury drug, how it interacts with myocardial necroptosis is not yet clear. Male C57BL/6 mice at 3-4- (young) and 22-24 months of age (aged) and RIPK3-deficient (Ripk3 -/- ) mice were used to investigate aging-related I/R injury in vivo. Metformin (125 μg/kg, i.p.), necrostatin-1 (3.5 mg/kg), and adenovirus vector encoding p62-shRNAs (Ad-sh-p62) were used to treat aging mice. I/R-induced myocardial necroptosis was exaggerated in aged mice, which correlated with autophagy defects characterized by p62 accumulation in aged hearts or aged human myocardium. Functionally, blocking autophagic flux promoted H/R-evoked cardiomyocyte necroptosis in vitro. We further revealed that p62 forms a complex with RIP1-RIP3 (necrosome) and promotes the binding of RIP1 and RIP3. In mice, necrostatin-1 treatment (a RIP1 inhibitor), RIP3 deficiency, and cardiac p62 knockdown in vivo demonstrated that p62-RIP1-RIP3-dependent myocardial necroptosis contributes to aging-related myocardial vulnerability to I/R injury. Notably, metformin treatment disrupted p62-RIP1-RIP3 complexes and effectively repressed I/R-induced necroptosis in aged hearts, ultimately reducing mortality in this model. These findings highlight previously unknown mechanisms of aging-related myocardial ischemic vulnerability: p62-necrosome-dependent necroptosis. Metformin acts as a cardioprotective agent that inhibits this unfavorable chain mechanism of aging-related I/R susceptibility., (© 2020 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Background: Emerging evidences indicate the important roles of autophagy in anti-oxidative stress, which is closely associated with cancer, aging and neurodegeneration., Objective: In the current study, we aimed to identify autophagy inducers with potent anti-oxidative effect from traditional Chinese medicines (TCMs) in PC-12 cells and C. elegans., Methods: The autophagy inducers were extensively screened in our herbal extracts library by using the stable RFP-GFP-LC3 U87 cells. The components with autophagic induction effect in Trillium tschonoskii Maxim. (TTM) was isolated and identified by using the autophagic activity-guided column chromatography and Pre-HPLC technologies, and MS and NMR spectroscopic analysis, respectively. The anti-oxidative effect of the isolated autophagy inducers was evaluated in H 2 O 2 -induced PC-12 cells and C. elegans models by measuring the viability of PC-12 cells and C. elegans, with quantitation on the ROS level in vitro and in vivo using H 2 DCFDA probe., Results: The total ethanol extract of TTM was found to significantly increase the formation of GFP-LC3 puncta in stable RFP-GFP-LC3 U87 cells. One novel steroidal saponin 1-O-[2,3,4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→2)-4-O-acetyl-α-L-arabinopyranosyl]-21-Deoxytrillenogenin, (Deoxytrillenoside CA, DTCA) and one known steroidal saponin 1-O-[2,3,4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→2)-4-O-acetyl-α-L-arabinopyranosyl]-21-O-acetyl-epitrillenogenin (Epitrillenoside CA, ETCA) were isolated, identified and found to have novel autophagic effect. Both DTCA and ETCA could activate autophagy in PC-12 cells via the AMPK/mTOR/p70S6K signaling pathway in an Atg7-dependent. In addition, DTCA and ETCA could increase the cell viability and decrease the intracellular ROS level in H 2 O 2 -treated PC-12 cells and C. elegans, and the further study demonstrated that the induced autophagy contributes to their anti-oxidative effect., Conclusion: Our current findings not only provide information on the discovery of novel autophagy activators from TTM, but also confirmed the anti-oxidative effect of the components from TTM both in vitro and in vivo., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Aims: In myocardial ischemia-reperfusion (MI/R) injury, impaired autophagy function worsens cardiomyocyte death. AMP-activated protein kinase (AMPK) is a heterotrimeric protein that plays an important role in cardioprotection and myocardial autophagic function. AMPKα1 and α2 are localized primarily in the cytoplasm and nucleus, respectively, in cardiomyocytes, but the isoform-specific autophagy regulation of AMPK during MI/R remains unclear., Materials and Methods: An MI/R model was built, and the protein expression of AMPKα1/α2, p-AMPK, mTOR, p-mTOR, TFEB, p-FoxO3a, SKP2, CARM1, TBP, Atg5, LAMP2, LC3B, and p62 during ischemia and reperfusion was determined by western blotting. Recombinant adeno-associated virus (serotype 9) vectors carrying tandem fluorescent-tagged LC3 or mRFP-GFP-LC3/GFP-LC3 were used to evaluate the autophagy status. AMPKα2 knockout mice were used for in vivo studies., Key Findings: Both cytoplasmic AMPKα1 and nuclear α2 subunit expression decreased during the reperfusion period, which led to AMPKα1-mTOR-TFEB and AMPKα2-Skp2-CARM1-TFEB signaling inhibition, respectively. The decreased TFEB level during reperfusion suppressed autophagy. Metformin could activate both the AMPKα1- and α2- mediated pathways, thus restoring autophagy flux during reperfusion. Nevertheless, in AMPKα2 knockout mice, nuclear α2-regulated Skp2-CARM1-TFEB signaling was inhibited, while α1-related signaling was comparatively unaffected, which partially impaired metformin-enhanced autophagy., Significance: Our study suggests that metformin had the dual effects of promoting both cytoplasmic AMPKα1- and nuclear AMPKα2-related signaling to improve autophagic flux and restore cardiac function during MI/R., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Autophagy is an essential cellular process concern with cellular homeostasis down-regulated by mTOR, whose activity can be modulated by rapamycin, a kind of lipophilic macrolide antibiotic, through forming a complex with immunophilin FKBP12 essential for mTOR regulation to induce autophagy. Therefore, rapamycin is normally used as a neuron protective agent. The immunophilin FKBP12 binding ligand FK506 is well known as an immunosuppressive agent by inhibiting the calcineurin expression. In this study, we synthesized a series of modified compounds based on the FKBP12 binding moiety to as same as the binding structure of rapamycin and FK506 particularly. We removed the other binding regions of the complex that has the property of immunosuppression. We found that a novel small molecule named TH2849 from these derivative compounds has a significant binding connection with mTOR by comparing to calcineurin. The effects of TH2849 on calcineurin/NFAT were not as significant as FK506, and weak effects on IL2/p34 cdc2 /cyclin signaling pathway were also found. Moreover, TH2849 also shows mitochondrial protective effect through stabilizing the mitochondrial structure and transmembrane potential (ΔΨm) and could rescue dopaminergic neurons in MPTP-treated zebrafishes as well as mice models with less immunosuppressive effect. Our present study shows that TH2849 works as a neuroprotective agent possibly by inducing autophagy and low immunosuppressive effect., (© 2018 John Wiley & Sons Ltd.)

Glucose produced from photosynthesis is a key nutrient signal regulating root meristem activity in plants; however, the underlying mechanisms remain poorly understood. Here, we show that, by modulating reactive oxygen species (ROS) levels, the conserved macroautophagy/autophagy degradation pathway contributes to glucose-regulated root meristem maintenance. In Arabidopsis thaliana roots, a short exposure to elevated glucose temporarily suppresses constitutive autophagosome formation. The autophagy-defective autophagy-related gene (atg) mutants have enhanced tolerance to glucose, established downstream of the glucose sensors, and accumulate less glucose-induced ROS in the root tips. Moreover, the enhanced root meristem activities in the atg mutants are associated with improved auxin gradients and auxin responses. By acting with AT4G39850/ABCD1 (ATP-binding cassette D1; Formerly PXA1/peroxisomal ABC transporter 1), autophagy plays an indispensable role in the glucose-promoted degradation of root peroxisomes, and the atg mutant phenotype is partially rescued by the overexpression of ABCD1. Together, our findings suggest that autophagy is an essential mechanism for glucose-mediated maintenance of the root meristem. Abbreviation: ABA: abscisic acid; ABCD1: ATP-binding cassette D1; ABO: ABA overly sensitive; AsA: ascorbic acid; ATG: autophagy related; CFP: cyan fluorescent protein; Co-IP: co-immunoprecipitation; DAB: 3',3'-diaininobenzidine; DCFH-DA: 2',7'-dichlorodihydrofluorescin diacetate; DR5: a synthetic auxin response element consists of tandem direct repeats of 11 bp that included the auxin-responsive TGTCTC element; DZ: differentiation zone; EZ, elongation zone; GFP, green fluorescent protein; GSH, glutathione; GUS: β-glucuronidase; HXK1: hexokinase 1; H 2 O 2 : hydrogen peroxide; IAA: indole-3-acetic acid; IBA: indole-3-butyric acid; KIN10/11: SNF1 kinase homolog 10/11; MDC: monodansylcadaverine; MS: Murashige and Skoog; MZ: meristem zone; NBT: nitroblue tetrazolium; NPA: 1-N-naphtylphthalamic acid; OxIAA: 2-oxindole-3-acetic acid; PIN: PIN-FORMED; PLT: PLETHORA; QC: quiescent center; RGS1: Regulator of G-protein signaling 1; ROS: reactive oxygen species; SCR: SCARECROW; SHR, SHORT-ROOT; SKL: Ser-Lys-Leu; SnRK1: SNF1-related kinase 1; TOR: target of rapamycin; UPB1: UPBEAT1; WOX5: WUSCHEL related homeobox 5; Y2H: yeast two-hybrid; YFP: yellow fluorescent protein.

A novel treatment regimen for bacterial infections is the pharmacological enhancement of the host's immune defenses. We demonstrated that biochanin A (BCA), an isoflavone constituent in some plants, could enhance both intra- and extracellular bactericidal activity of host cells. First, BCA could induce a complete autophagic response in nonphagocytic cells (HeLa) or macrophages (MΦ) via the AMPK/ULK1/mTOR pathway and Beclin-1-dependent manner, and BCA enhanced the killing of invading Salmonella by autophagy through reinforcing ubiquitinated adapter protein (LRSAM1, NDP52 and p62)-mediated recognition of intracellular bacteria and through the formation of autophagolysosomes. Second, we demonstrated that BCA could enhance the release of MΦ extracellular traps (METs) to remove extracellular Salmonella also via the AMPK/ULK1/mTOR pathway, not through reactive oxygen species (ROS) pathway. Furtherly, in a Salmonella -infected mouse model, BCA treatment increased intra- and extracellular bactericidal activity through the strengthening autophagy and MET production, respectively, in peritoneal MΦ, liver and spleen tissue. Additionally, our findings showed that BCA downregulated SPI-1 ( Salmonella pathogenicity island 1) expression during Salmonella infection in vitro and in vivo to reverse the MΦ M2 polarization, which was different from the MΦ M1 phenotype caused by most of bacteria infection. Together, these findings suggest that BCA has an immunomodulatory effect on Salmonella -infected host cells and enhances their bactericidal activity in vitro and in vivo through autophagy, extracellular traps and regulation of MΦ polarization.

Senescence-associated autophagy downregulation leads to cardiomyocyte dysfunction. Coactivator-associated arginine methyltransferase 1 (CARM1) participates in many cellular processes, including autophagy in mammals. However, the effect of CARM1 in aging-related cardiac autophagy decline remains undefined. Moreover, AMP-activated protein kinase (AMPK) is a key regulator in metabolism and autophagy, however, the role of nuclear AMPK in autophagy outcome in aged hearts still unclear. Hers we identify the correlation between nuclear AMPK and CARM1 in aging heart. We found that fasting could promote autophagy in young hearts but not in aged hearts. The CARM1 stabilization is markedly decrease in aged hearts, which impaired nucleus TFEB-CARM1 complex and autophagy flux. Further, S-phase kinase-associated protein 2(SKP2), responsible for CARM1 degradation, was increased in aged hearts. We further validated that AMPK dependent FoxO3 phosphorylation was markedly reduced in nucleus, the decreased nuclear AMPK-FoxO3 activity fails to suppress SKP2-E3 ubiquitin ligase. This loss of repression leads to The CARM1 level and autophagy in aged hearts could be restored through AMPK activation. Taken together, AMPK deficiency results in nuclear CARM1 decrease mediated in part by SKP2, contributing to autophagy dysfunction in aged hearts. Our results identified nuclear AMPK controlled CARM1 stabilization as a new actor that regulates cardiac autophagy., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Aflatoxins are a group of highly toxic mycotoxins with high carcinogenicity that are commonly found in foods. Aflatoxin B1 (AFB1) is the most toxic member of the aflatoxin family. A recent study reported that AFB1 can induce autophagy, but whether AFB1 can induce extracellular traps (ETs) and the relationships among innate immune responses, reactive oxygen species (ROS), and autophagy and the ETs induced by AFB1 remain unknown. Here, we demonstrated that AFB1 induced a complete autophagic process in macrophages (MΦ) (THP-1 cells and RAW264.7 cells). In addition, AFB1 induced the generation of MΦ ETs (METs) in a dose-dependent manner. In particular, the formation of METs significantly reduced the AFB1 content. Further analysis using specific inhibitors showed that the inhibition of either autophagy or ROS prevented MET formation caused by AFB1, indicating that autophagy and ROS were required for AFB1-induced MET formation. The inhibition of ROS prevented autophagy, indicating that ROS generation occurred upstream of AFB1-induced autophagy. Taken together, these data suggest that AFB1 induces ROS-mediated autophagy and ETs formation and an M1 phenotype in MΦ.

Lysosomes, the cell's recycling center, undergo nutrient-sensitive adaptive changes in function and biogenesis, i.e., lysosomal adaptation. We recently discovered that lysosomes also mediate the cell's "survival" response (i.e., autophagy) to oxidative stress through the activation of TFEB (transcription factor EB), a master regulator of lysosome biogenesis and autophagy. MCOLN1/TRPML1, the principal Ca 2+ release channel on the lysosomal membrane, serves as the redox sensor in this process. Increasing reactive oxygen species (ROS) levels, either endogenously by mitochondrial damage or exogenously, directly activates MCOLN1 to induce lysosomal Ca 2+ release, triggering PPP3/calcineurin-dependent TFEB nuclear translocation to enhance autophagy. Hence, ROS may induce autophagy by activating the MCOLN1-lysosome Ca 2+ -TFEB pathway, facilitating the removal of damaged mitochondria and excess ROS. Our findings have revealed a lysosomal signaling mechanism for cells to respond to oxidative bursts and adapt to oxidative stress.

A recent study reported that Acinetobacter baumannii could induce autophagy, but the recognition and clearance mechanism of intracytosolic A. baumannii in the autophagic process and the molecular mechanism of autophagy induced by the pathogen remains unknown. In this study, we first demonstrated that invading A. baumannii induced a complete, ubiquitin-mediated autophagic response that is dependent upon septins SEPT2 and SEPT9 in mammalian cells. We also demonstrated that autophagy induced by A. baumannii was Beclin-1 dependent via the AMPK/ERK/mammalian target of rapamycin pathway. Of interest, we found that the isochorismatase mutant strain had significantly decreased siderophore-mediated ferric iron acquisition ability and had a reduced the ability to induce autophagy. We verified that isochorismatase was required for the recognition of intracytosolic A. baumannii mediated by septin cages, ubiquitinated proteins, and ubiquitin-binding adaptor proteins p62 and NDP52 in autophagic response. We also confirmed that isochorismatase was required for the clearance of invading A. baumannii by autophagy in vitro and in the mouse model of infection. Together, these findings provide insight into the distinctive recognition and clearance of intracytosolic A. baumannii by autophagy in host cells, and that isochorismatase plays a critical role in the A. baumannii-induced autophagic process.-Wang, Y., Zhang, K., Shi, X., Wang, C., Wang, F., Fan, J., Shen, F., Xu, J., Bao, W., Liu, M., Yu, L. Critical role of bacterial isochorismatase in the autophagic process induced by Acinetobacter baumannii in mammalian cells., (© The Author(s).)

Cellular stresses trigger autophagy to remove damaged macromolecules and organelles. Lysosomes 'host' multiple stress-sensing mechanisms that trigger the coordinated biogenesis of autophagosomes and lysosomes. For example, transcription factor (TF)EB, which regulates autophagy and lysosome biogenesis, is activated following the inhibition of mTOR, a lysosome-localized nutrient sensor. Here we show that reactive oxygen species (ROS) activate TFEB via a lysosomal Ca(2+)-dependent mechanism independent of mTOR. Exogenous oxidants or increasing mitochondrial ROS levels directly and specifically activate lysosomal TRPML1 channels, inducing lysosomal Ca(2+) release. This activation triggers calcineurin-dependent TFEB-nuclear translocation, autophagy induction and lysosome biogenesis. When TRPML1 is genetically inactivated or pharmacologically inhibited, clearance of damaged mitochondria and removal of excess ROS are blocked. Furthermore, TRPML1's ROS sensitivity is specifically required for lysosome adaptation to mitochondrial damage. Hence, TRPML1 is a ROS sensor localized on the lysosomal membrane that orchestrates an autophagy-dependent negative-feedback programme to mitigate oxidative stress in the cell.

Cardiac aging is characterized by accumulation of damaged proteins and decline of autophagic efficiency. Here, by forestalling SIRT1 carbonylated inactivation in aged heart, we determined the benefits of activation of aldehyde dehydrogenase 2 (ALDH2) on the autophagy. In this study, the ALDH2 KO mice progressively developed age-related heart dysfunction and showed reduction in the life span, which strongly suggests that ALDH2 ablation leads to cardiac aging. What's more, aged hearts displayed a significant decrease ALDH2 activity, resulting in accumulation of 4-HNE-protein adducts and protein carbonyls, impairment in the autophagy flux, and, consequently, deteriorated cardiac function after starvation. Sustained Alda-1 (selective ALDH2 activator) treatment increased cardiac ALDH2 activity and abrogated these effects. Using SIRT1 deficient heterozygous (Sirt1+/-) mice, we found that SIRT1 was necessary for ALDH2 activation-induced autophagy. We further demonstrated that ALDH2 activation attenuated SIRT1 carbonylation and improved SIRT1 activity, thereby increasing the deacetylation of nuclear LC3 and FoxO1. Sequentially, ALDH2 enhanced SIRT1 regulates LC3-Atg7 interaction and FoxO1 increased Rab7 expression, which were both necessary and sufficient for restoring autophagy flux. These results highlight that both accumulation of proteotoxic carbonyl stress linkage with autophagy decline contribute to heart senescence. ALDH2 activation is adequate to improve the autophagy flux by reducing the carbonyl modification on SIRT1, which in turn plays an important role in maintaining cardiac health during aging.

Autophagy involves massive degradation of intracellular components and functions as a conserved system that helps cells to adapt to adverse conditions. In mammals, hypoxia rapidly stimulates autophagy as a cell survival response. Here, we examine the function of autophagy in the regulation of the plant response to submergence, an abiotic stress that leads to hypoxia and anaerobic respiration in plant cells. In Arabidopsis thaliana, submergence induces the transcription of autophagy-related (ATG) genes and the formation of autophagosomes. Consistent with this, the autophagy-defective (atg) mutants are hypersensitive to submergence stress and treatment with ethanol, the end product of anaerobic respiration. Upon submergence, the atg mutants have increased levels of transcripts of anaerobic respiration genes (alcohol dehydrogenase 1, ADH1 and pyruvate decarboxylase 1, PDC1), but reduced levels of transcripts of other hypoxia- and ethylene-responsive genes. Both submergence and ethanol treatments induce the accumulation of reactive oxygen species (ROS) in the rosettes of atg mutants more than in the wild type. Moreover, the production of ROS by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases is necessary for plant tolerance to submergence and ethanol, submergence-induced expression of ADH1 and PDC1, and activation of autophagy. The submergence- and ethanol-sensitive phenotypes in the atg mutants depend on a complete salicylic acid (SA) signaling pathway. Together, our findings demonstrate that submergence-induced autophagy functions in the hypoxia response in Arabidopsis by modulating SA-mediated cellular homeostasis.

Thiacloprid (THI) is a neonicotinoid insecticide, and its wide‐ranging use has contributed to severe environmental and health problems. Dendrobium officinale polysaccharide (DOP) possesses multiple biological activities such as antioxidant and antiapoptosis effect. Although present research has shown that THI causes kidney injury, the exact molecular mechanism and treatment of THI‐induced kidney injury remain unclear. The study aimed to investigate if DOP could alleviate THI‐induced kidney injury and identify the potential molecular mechanism in quails. In this study, Japanese quails received DOP (200 mg/kg) daily with or without THI (4 mg/kg) exposure for 42 days. Our results showed that DOP improved hematological changes, biochemical indexes, and nephric histopathological changes induced by THI. Meanwhile, THI exposure caused oxidative stress, apoptosis, and autophagy. Furthermore, THI and DOP cotreatment significantly activated the nuclear factor erythroid 2‐related factor 2/heme oxygenase‐1 (Nrf2/HO‐1) pathway, restored antioxidant enzyme activity, and reduced apoptosis and autophagy in quail kidneys. In summary, our study demonstrated that DOP mitigated THI‐mediated kidney injury was associated with oxidative stress, apoptosis, and autophagy via activation of the Nrf2/HO‐1 signaling pathway in quails. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration is a macular disease which incidence increases with age. Currently, it is believed that its pathogenic factors are related to patients' age, heredity, smoking, oxidative stress, immune inflammatory response, RPE cell aging and metabolic abnormalities. Complement system plays an important role in the body's defense against infection, immune regulation and inflammatory response. Immune inflammation caused by abnormal activation of complement system is considered to be an important cause of ARMD in recent years. Autophagy also plays a role in ARMD. Normal autophagy is an important way for cells' self-protection and maintenance of homeostasis. When autophagy is blocked, oxidative stress can be aggravated, which will lead to the development of ARMD. The balance regulation between complement activation and autophagy is an important method to control the development of ARMD.

The global application of engineered nanomaterials and nanoparticles (ENPs) in commercial products, industry, and medical fields has raised some concerns about their safety. These nanoparticles may gain access into rivers and marine environments through industrial or household wastewater discharge and thereby affect the ecosystem. In this study, we investigated the effects of silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) on zebrafish embryos in aquatic environments. We aimed to characterize the AgNP and ZnONP aggregates in natural waters, such as lakes, reservoirs, and rivers, and to determine whether they are toxic to developing zebrafish embryos. Different toxic effects and mechanisms were investigated by measuring the survival rate, hatching rate, body length, reactive oxidative stress (ROS) level, apoptosis, and autophagy. Spiking AgNPs or ZnONPs into natural water samples led to significant acute toxicity to zebrafish embryos, whereas the level of acute toxicity was relatively low when compared to Milli-Q (MQ) water, indicating the interaction and transformation of AgNPs or ZnONPs with complex components in a water environment that led to reduced toxicity. ZnONPs, but not AgNPs, triggered a significant delay of embryo hatching. Zebrafish embryos exposed to filtered natural water spiked with AgNPs or ZnONPs exhibited increased ROS levels, apoptosis, and lysosomal activity, an indicator of autophagy. Since autophagy is considered as an early indicator of ENP interactions with cells and has been recognized as an important mechanism of ENP-induced toxicity, developing a transgenic zebrafish system to detect ENP-induced autophagy may be an ideal strategy for predicting possible ecotoxicity that can be applied in the future for the risk assessment of ENPs.

Alzheimer's disease (AD) presents a significant challenge to global healthcare systems, with current treatments offering only modest relief and often bringing unwanted side effects, necessitating the exploration of more effective and safer drugs. In this study, we employed the Caenorhabditis elegans (C. elegans) model, specifically the AD-like CL4176 strain expressing the human Aβ(1–42) protein, to investigate the potential of Reineckia carnea extract and its fractions. Our results showed that the Reineckia carnea ether fraction (REF) notably diminished the paralysis rates of CL4176 worms. Additionally, REF also attenuated the neurotoxicity effects prompted by Tau proteins in the BR5270 worms. Moreover, REF was observed to counteract the accumulation of Aβ and pTau proteins and their induced oxidative stress in C. elegans AD-like models. Mechanistic studies revealed that REF's benefits were associated with the induction of autophagy in worms; however, these protective effects were nullified when autophagy-related genes were suppressed using RNAi bacteria. Together, these findings highlight Reineckia carnea ether fraction as a promising candidate for AD treatment, warranting further investigation into its autophagy-inducing components and their molecular mechanisms. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) is a prevalent neurodegenerative disorder without an effective cure. Natural products, while showing promise as potential therapeutics for AD, remain underexplored. Aims: This study was conducted with the goal of identifying potential anti‐AD candidates from natural sources using Caenorhabditis elegans (C. elegans) AD‐like models and exploring their mechanisms of action. Materials & Methods: Our laboratory's in‐house herbal extract library was utilized to screen for potential anti‐AD candidates using the C. elegans AD‐like model CL4176. The neuroprotective effects of the candidates were evaluated in multiple C. elegans AD‐like models, specifically targeting Aβ‐ and Tau‐induced pathology. In vitro validation was conducted using PC‐12 cells. To investigate the role of autophagy in mediating the anti‐AD effects of the candidates, RNAi bacteria and autophagy inhibitors were employed. Results: The ethanol extract of air‐dried fruits of Luffa cylindrica (LCE), a medicine‐food homology species, was found to inhibit Aβ‐ and Tau‐induced pathology (paralysis, ROS production, neurotoxicity, and Aβ and pTau deposition) in C. elegans AD‐like models. LCE was non‐toxic and enhanced C. elegans' health. It was shown that LCE activates autophagy and its anti‐AD efficacy is weakened with the RNAi knockdown of autophagy‐related genes. Additionally, LCE induced mTOR‐mediated autophagy, reduced the expression of AD‐associated proteins, and decreased cell death in PC‐12 cells, which was reversed by autophagy inhibitors (bafilomycin A1 and 3‐methyladenine). Discussion: LCE, identified from our natural product library, emerged as a valuable autophagy enhancer that effectively protects against neurodegeneration in multiple AD‐like models. RNAi knockdown of autophagy‐related genes and cotreatment with autophagy inhibitors weakened its anti‐AD efficacy, implying a critical role of autophagy in mediating the neuroprotective effects of LCE. Conclusion: Our findings highlight the potential of LCE as a functional food or drug for targeting AD pathology and promoting human health. [ABSTRACT FROM AUTHOR]

Introduction: Carnosine can suppress secondary complications in diabetes and show robust neuroprotective activity against neurodegenerative diseases. Here, we report that carnosine ameliorates diabetes-associated cognitive decline in vivo through the modulation of autophagy. Methods: A high-fat diet (HFD) and one intraperitoneal injection of 30 mg/kg streptozotocin (STZ) were used to induce type 2 diabetes mellitus in Sprague-Dawley rats. The rats were randomly divided into five groups: control (CON), HFD/STZ, and three intragastric carnosine treatment groups receiving low (100 mg/kg), medium (300 mg/kg), and high (900 mg/kg) doses over 12 weeks. Body weight, blood glucose levels, and cognitive function were continuously monitored. From excised rat hippocampi, we determined superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels; carnosine concentration; protein expressions of Akt, mTOR and the autophagy markers LC3B and P62 and performed histopathological evaluations of the cornu ammonis 1 region. Results: The HFD/STZ group showed increased blood glucose levels and decreased body weight compared to the CON group. However, there were no significant differences in body weight and blood glucose levels between carnosine-treated and -untreated HFD-STZ-induced diabetic rats. Diabetic animals showed obvious learning and memory impairments in the Morris water maze test compared to the CON group. Compared to those in the HFD/STZ group, carnosine increased SOD activity and decreased MDA levels, increased hippocampal carnosine concentration, increased p-Akt and p-mTOR expression, decreased LC3B and P62 expression, alleviated neuronal injuries, and improved cognitive performance in a dose-dependent manner. Conclusion: Independent of any hyperglycemic effect, carnosine may improve mild cognitive impairments by mitigating oxidative stress, activating the Akt/mTOR pathway, and modulating autophagy in the hippocampus of type 2 diabetic rats. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is the second most common neurodegenerative disease. Chlorogenic acid (CGA) is a polyphenolic substance derived from various medicinal plants. Although CGA is reported to have potential anti-PD effect, the beneficial effect and the underlying mechanism remain unclear. In this study, we aimed to further investigate the protective effect and clarify the mechanism of action of CGA in Caenorhabditis elegans (C. elegans) models of PD. Measurements of a-synuclein aggregation, movement disorders, and lipid, ROS and malondialdehyde (MDA) contents were observed in NL5901 nematodes. Determinations of dopamine (DA) neuron degeneration, food perception, and ROS content were performed in 6-OHDA-exposed BZ555 nematodes. The autophagy activation of CGA was monitored using DA2123 and BC12921 nematodes. Meanwhile, RNAi technology was employed to knockdown the autophagy-related genes and investigate whether the anti-PD effect of CGA was associated with autophagy induction in C. elegans. CGA significantly reduced α-synuclein aggregation, improved motor disorders, restored lipid content, and decreased ROS and MDA contents in NL5901 nematodes. Meanwhile, CGA inhibited DA neuron-degeneration and improved food-sensing behavior in 6-OHDA-exposed BZ555 nematodes. In addition, CGA increased the number of GFP::LGG-1 foci in DA2123 nematodes and degraded p62 protein in BC12921 nematodes. Meanwhile, CGA up-regulated the expression of autophagy-related genes in NL5901 nematodes. Moreover, the anti-PD effect of CGA was closely related to autophagy induction via increasing the expression of autophagy-related genes, including unc-51, bec-1, vps-34, and lgg-1. The present study indicates that CGA exerts neuroprotective effect in C. elegans via autophagy induction. [ABSTRACT FROM AUTHOR]

Nutrition intervention has emerged as a potential strategy to delay aging and promote healthy longevity. Citri Reticulatae Semen (CRS) has diverse beneficial effects and has been used for thousands of years to treat pain. However, the health benefits of CRS in prolonging health span and improving aging-related diseases and the exact mechanisms remain poorly characterized. In this study, Caenorhabditis elegans (C. elegans) was used as a model organism to study the antiaging and health span promoting activities of 75% ethanol extract of CRS (CRSE). The results showed that treatment with CRSE at 1 000 μg/mL significantly extended the life span of worms by 18.93% without detriment to health span and fitness, as evidenced by the delayed aging-related phenotypes and increased body length and width, and reproductive output. In addition, CRSE treatment enhanced the ability of resistance to heat, oxidative, and pathogenic bacterial stress. Consistently, heat shock proteins and antioxidant enzyme-related and pathogenesis-related genes were up-regulated by CRSE treatment. Furthermore, CRSE supplementation also improved α-synuclein, 6-OHDA, and polyQ40-induced pathologies in transgenic C. elegans models of Parkinson's disease and Huntington's disease. The mechanistic study demonstrated that CRSE induced autophagy in worms, while the RNAi knockdown of 4 key autophagy-related genes, including lgg-1, bec-1, vps-34, and unc-51, remarkably abrogated the beneficial effects of CRSE on the extending of life span and health span and neuroprotection, demonstrating that CRSE exerts beneficial effects via autophagy induction in worms. Together, our current findings provide new insights into the practical application of CRS for the prevention of aging and aging-related diseases. [ABSTRACT FROM AUTHOR]

Autophagy has been implicated in the regulation of neuroinflammation and neurodegenerative disorders. Licochalcone B (LCB), a chalcone from Glycyrrhiza inflata, has been reported to have anti-cancer, anti-oxidation and anti-β–amyloid fibrillation effects; however, its effect in autophagy remain un-investigated. In the current study, the potential neuro-protective role of LCB in terms of its anti-oxidative, anti-apoptotic, and autophagic properties upon oxidative stress-induced damage in neuronal cells was investigated. With the production of reactive oxygen species (ROS) as a hallmark of neuroinflammation and neurodegeneration, hydrogen peroxide (H2O2) was adopted to stimulate ROS-induced cell apoptosis in PC-12 cells. Our findings revealed that LCB reduced cell cytotoxicity and apoptosis of PC-12 cells upon H2O2-stimulation. Furthermore, LCB increased the level of the apoptosis-associated proteins caspase-3 and cleaved caspase-3 in H2O2-induced cells. LCB effectively attenuated the level of oxidative stress markers such as MDA, SOD, and ROS in H2O2-induced cells. Most importantly, LCB was confirmed to possess its anti-apoptotic effects in H2O2-induced cells through the induction of ATG7-dependent autophagy and the SIRT1/AMPK signaling pathway. As a novel autophagic inducer, LCB increased the level of autophagy-related proteins LC3–II and decreased p62 in both neuronal cells and Caenorhabditis elegans (C. elegans) models. These results suggested that LCB has potential neuroprotective effects on oxidative damage models via multiple protective pharmacological mechanisms. [ABSTRACT FROM AUTHOR]

Background and Purpose: Celastrol exhibits anti-arthritic effects in rheumatoid arthritis (RA), but the role of celastrol-mediated Ca2+ mobilization in treatment of RA remains undefined. Here, we describe a regulatory role for celastrol-induced Ca2+ signalling in synovial fibroblasts of RA patients and adjuvant-induced arthritis (AIA) in rats.Experimental Approach: We used computational docking, Ca2+ dynamics and functional assays to study the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase pump (SERCA). In rheumatoid arthritis synovial fibroblasts (RASFs)/rheumatoid arthritis fibroblast-like synoviocytes (RAFLS), mechanisms of Ca2+ -mediated autophagy were analysed by histological, immunohistochemical and flow cytometric techniques. Anti-arthritic effects of celastrol, autophagy induction, and growth rate of synovial fibroblasts in AIA rats were monitored by microCT and immunofluorescence staining. mRNA from joint tissues of AIA rats was isolated for transcriptional analysis of inflammatory genes, using siRNA methods to study calmodulin, calpains, and calcineurin.Key Results: Celastrol inhibited SERCA to induce autophagy-dependent cytotoxicity in RASFs/RAFLS via Ca2+ /calmodulin-dependent kinase kinase-β-AMP-activated protein kinase-mTOR pathway and repressed arthritis symptoms in AIA rats. BAPTA/AM hampered the in vitro and in vivo effectiveness of celastrol. Inflammatory- and autoimmunity-associated genes down-regulated by celastrol in joint tissues of AIA rat were restored by BAPTA/AM. Knockdown of calmodulin, calpains, and calcineurin in RAFLS confirmed the role of Ca2+ in celastrol-regulated gene expression.Conclusion and Implications: Celastrol triggered Ca2+ signalling to induce autophagic cell death in RASFs/RAFLS and ameliorated arthritis in AIA rats mediated by calcium-dependent/-binding proteins facilitating the exploitation of anti-arthritic drugs based on manipulation of Ca2+ signalling. [ABSTRACT FROM AUTHOR]

With population aging, the incidence of aging-related Alzheimer's disease (AD) is increasing, accompanied by decreased autophagy activity. At present, Caenorhabditis elegans (C. elegans) is widely employed to evaluate autophagy and in research on aging and aging-related diseases in vivo. To discover autophagy activators from natural medicines and investigate their therapeutic potential in antiaging and anti-AD effects, multiple C. elegans models related to autophagy, aging, and AD were used. In this study, we employed the DA2123 and BC12921 strains to discover potential autophagy inducers using a self-established natural medicine library. The antiaging effect was evaluated by determining the lifespan, motor ability, pumping rate, lipofuscin accumulation of worms, and resistance ability of worms under various stresses. In addition, the anti-AD effect was examined by detecting the paralysis rate, food-sensing behavior, and amyloid-β and Tau pathology in C. elegans. Moreover, RNAi technology was used to knock down the genes related to autophagy induction. We discovered that Piper wallichii extract (PE) and the petroleum ether fraction (PPF) activated autophagy in C. elegans , as evidenced by increased GFP-tagged LGG-1 foci and decreased GFP-p62 expression. In addition, PPF extended the lifespan and enhanced the healthspan of worms by increasing body bends and pumping rates, decreasing lipofuscin accumulation, and increasing resistance to oxidative, heat, and pathogenic stress. Moreover, PPF exhibited an anti-AD effect by decreasing the paralysis rate, improving the pumping rate and slowing rate, and alleviating Aβ and Tau pathology in AD worms. However, the feeding of RNAi bacteria targeting unc-51, bec-1, lgg-1 , and vps-34 abolished the antiaging and anti-AD effects of PPF. : Piper wallichii may be a promising drug for antiaging and anti-AD. More future studies are also needed to identify autophagy inducers in Piper wallichii and clarify their molecular mechanisms. [ABSTRACT FROM AUTHOR]

Protein aggregates are considered key pathological features in neurodegenerative diseases (NDs). The induction of autophagy can effectively promote the clearance of ND-related misfolded proteins. In this study, we aimed to screen natural autophagy enhancers from traditional Chinese medicines (TCMs) presenting potent neuroprotective potential in multiple ND models. The autophagy enhancers were broadly screened in our established herbal extract library using the transgenic Caenorhabditis elegans (C. elegans) DA2123 strain. The neuroprotective effects of the identified autophagy enhancers were evaluated in multiple C. elegans ND models by measuring Aβ-, Tau-, α-synuclein-, and polyQ40-induced pathologies. In addition, PC-12 cells and 3 × Tg-AD mice were employed to further validate the neuroprotective ability of the identified autophagy enhancers, both in vitro and in vivo. Furthermore, RNAi bacteria and autophagy inhibitors were used to evaluate whether the observed effects of the identified autophagy enhancers were mediated by the autophagy-activated pathway. The ethanol extract of Folium Hibisci Mutabilis (FHME) was found to significantly increase GFP::LGG-1-positive puncta in the DA2123 worms. FHME treatment markedly inhibited Aβ, α-synuclein, and polyQ40, as well as prolonging the lifespan and improving the behaviors of C. elegans , while siRNA targeting four key autophagy genes partly abrogated the protective roles of FHME in C. elegans. Additionally, FHME decreased the expression of AD-related proteins and restored cell viability in PC-12 cells, which were canceled by cotreatment with 3-methyladenine (3-MA) or bafilomycin A1 (Baf). Moreover, FHME ameliorated AD-like cognitive impairment and pathology, as well as activating autophagy in 3 × Tg-AD mice. FHME was successfully screened from our natural product library as a potent autophagy enhancer that exhibits a neuroprotective effect in multiple ND models across species through the induction of autophagy. These findings offer a new and reliable strategy for screening autophagy inducers, as well as providing evidence that FHME may serve as a possible therapeutic agent for NDs. [Display omitted] [ABSTRACT FROM AUTHOR]

Aims The present study was designed to examine the mechanism involved in mitochondrial aldehyde dehydrogenase (ALDH2)-induced cardioprotection against ischaemia/reperfusion (I/R) injury with a focus on autophagy. Methods Wild-type (WT), ALDH2 overexpression, and knockout (KO) mice (n = 4–6 for each index measured) were subjected to I/R, and myocardial function was assessed using echocardiographic, Langendroff, and edge-detection systems. Western blotting was used to evaluate AMP-dependent protein kinase (AMPK), Akt, autophagy, and the AMPK/Akt upstream signalling LKB1 and PTEN. Results ALDH2 overexpression and KO significantly attenuated and accentuated, respectively, infarct size, factional shortening, and recovery of post-ischaemic left ventricular function following I/R as well as hypoxia/reoxygenation-induced cardiomyocyte contractile dysfunction. Autophagy was induced during ischaemia and remained elevated during reperfusion. ALDH2 significantly promoted autophagy during ischaemia, which was accompanied by AMPK activation and mammalian target of rapamycin (mTOR) inhibition. On the contrary, ALDH2 overtly inhibited autophagy during reperfusion accompanied by the activation of Akt and mTOR. Inhibition and induction of autophagy mitigated ALDH2-induced protection against cell death in hypoxia and reoxygenation, respectively. In addition, levels of the endogenous toxic aldehyde 4-hydroxy-2-nonenal (4-HNE) were elevated by ischaemia and reperfusion, which was abrogated by ALDH2. Furthermore, ALDH2 ablated 4-HNE-induced cardiomyocyte dysfunction and protein damage, whereas 4-HNE directly decreased pan and phosphorylated LKB1 and PTEN expression. Conclusion Our data suggest a myocardial protective effect of ALDH2 against I/R injury possibly through detoxification of toxic aldehyde and a differential regulation of autophagy through AMPK- and Akt-mTOR signalling during ischaemia and reperfusion, respectively. [ABSTRACT FROM PUBLISHER]

ARG2 has been reported to inhibit autophagy in vascular endothelial cells and keratinocytes. However, studies of its mechanism of action, its role in skin fibroblasts, and the possibility of promoting autophagy and inhibiting cellular senescence through ARG2 inhibition are lacking. We induced cellular senescence in dermal fibroblasts by using H2O2. H2O2-induced fibroblast senescence was inhibited upon ARG2 knockdown and promoted upon ARG2 overexpression. The microRNA miR-1299 suppressed ARG2 expression, thereby inhibiting fibroblast senescence, and miR-1299 inhibitors promoted dermal fibroblast senescence by upregulating ARG2. Using yeast two-hybrid assay, we found that ARG2 binds to ARL1. ARL1 knockdown inhibited autophagy and ARL1 overexpression promoted it. Resolvin D1 (RvD1) suppressed ARG2 expression and cellular senescence. These data indicate that ARG2 stimulates dermal fibroblast cell senescence by inhibiting autophagy after interacting with ARL1. In addition, RvD1 appears to promote autophagy and inhibit dermal fibroblast senescence by inhibiting ARG2 expression. Taken together, the miR-1299/ARG2/ARL1 axis emerges as a novel mechanism of the ARG2-induced inhibition of autophagy. Furthermore, these results indicate that miR-1299 and pro-resolving lipids, including RvD1, are likely involved in inhibiting cellular senescence by inducing autophagy. [ABSTRACT FROM AUTHOR]

In response to hypoxia under submergence, plants switch from aerobic respiration to anaerobic fermentation, which leads to the accumulation of the end product, ethanol. We previously reported that Arabidopsis thaliana autophagy-deficient mutants show increased sensitivity to ethanol treatment, indicating that ethanol is likely involved in regulating the autophagy-mediated hypoxia response. Here, using a transcriptomic analysis, we identified 3909 genes in Arabidopsis seedlings that were differentially expressed in response to ethanol treatment, including 2487 upregulated and 1422 downregulated genes. Ethanol treatment significantly upregulated genes involved in autophagy and the detoxification of reactive oxygen species. Using transgenic lines expressing AUTOPHAGY-RELATED PROTEIN 8e fused to green fluorescent protein (GFP-ATG8e), we confirmed that exogenous ethanol treatment promotes autophagosome formation in vivo. Phenotypic analysis showed that deletions in the alcohol dehydrogenase gene in adh1 mutants result in attenuated submergence tolerance, decreased accumulation of ATG proteins, and diminished submergence-induced autophagosome formation. Compared to the submergence-tolerant Arabidopsis accession Columbia (Col-0), the submergence-intolerant accession Landsberg erecta (Ler) displayed hypersensitivity to ethanol treatment; we linked these phenotypes to differences in the functions of ADH1 and the autophagy machinery between these accessions. Thus, ethanol promotes autophagy-mediated submergence tolerance in Arabidopsis. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI)) is a ubiquitous environmental pollutant that can cause reproductive toxicity. However, the exact mechanism of Cr(VI)-induced testis toxicity remains largely elusive. This study aims to explore the possible molecular mechanism of Cr(VI)-provoked testicular toxicity. Male Wistar rats were intraperitoneally injected with 0, 2, 4, or 6 mg/kg body weight/day of potassium dichromate (K 2 Cr 2 O 7), respectively, for 5 weeks. The results revealed that Cr(VI)-treated rat testis presented varying degrees of damage in a dose-dependent manner. Concretely, Cr(VI) administration suppressed Sirtuin 1/Peroxisome proliferator-activated receptor-γ coactivator-1α pathway and led to mitochondrial dynamics disorder, along with the elevation of mitochondrial division and the repression of mitochondrial fusion. Meanwhile, the downstream effector of Sirt1, nuclear factor-erythroid-2-related factor 2 (Nrf2), was downregulated, and correspondingly exacerbated oxidative stress. Mitochondrial dynamics disorder and Nrf2 inhibition collectively contribute to abnormal mitochondrial dynamics in testis, which further promotes apoptosis and autophagy, evidenced by dose-dependently increasing the protein levels and gene expressions of apoptosis-related (including Bcl-2-associated X protein, cytochrome c , and cleaved-caspase 3) and autophagy-related (Beclin-1, ATG4B, and ATG5). Collectively, our results demonstrate that Cr(VI) exposure induced testis apoptosis and autophagy by disrupting the balance of mitochondrial dynamics and the oxidation-reduction process in rats. • K 2 Cr 2 O 7 induces mitochondrial dynamics disorder in rat testis by inhibiting Sirt1/PGC-1α axis. • K 2 Cr 2 O 7 exposure aggravates inhibition of Nrf2 pathway and promotes oxidative stress. • K 2 Cr 2 O 7 exposure promotes apoptosis and autophagy, leading to testicular damage. [ABSTRACT FROM AUTHOR]

Activation of the NLRP3 inflammasome and its mediated neuroinflammation are implicated in neurodegenerative diseases, while mitophagy negatively regulates NLRP3 inflammasome activation. SHP-2, a protein-tyrosine phosphatase, is critical for NLRP3 inflammasome regulation and inflammatory responses. In this study, we investigated whether triterpenoid saponins in Radix Polygalae inhibit the NLRP3 inflammasome via mitophagy induction. First, we isolated the active fraction (polygala saponins (PSS)) and identified 17 saponins by ultra-performance liquid chromatography coupled with diode-array detection and tandem quadrupole time-of-flight mass spectrometry (UHPLC-DAD-Q/TOF-MS). In microglial BV-2 cells, PSS induced mitophagy as evidenced by increased co-localization of LC3 and mitochondria, as well as an increased number of autophagic vacuoles surrounding the mitochondria. Furthermore, the mechanistic study found that PSS activated the AMPK/mTOR and PINK1/parkin signaling pathways via the upregulation of SHP-2. In Aβ(1-42)-, A53T-α-synuclein-, or Q74-induced BV-2 cells, PSS significantly inhibited NLRP3 inflammasome activation, which was attenuated by bafilomycin A1 (an autophagy inhibitor) and SHP099 (an SHP-2 inhibitor). In addition, the co-localization of LC3 and ASC revealed that PSS promoted the autophagic degradation of the NLRP3 inflammasome. Moreover, PSS decreased apoptosis in conditioned medium-induced PC-12 cells. In APP/PS1 mice, PSS improved cognitive function, ameliorated Aβ pathology, and inhibited neuronal death. Collectively, the present study, for the first time, shows that PSS inhibit the NLRP3 inflammasome via SHP-2-mediated mitophagy in vitro and in vivo, which strongly suggests the therapeutic potential of PSS in various neurodegenerative diseases. [Display omitted] • Polygala saponins (PSS) activate mitophagy via SHP-2-mediated AMPK/mTOR and PINK1/Parkin signaling pathways in BV-2 cells. • PSS promote the autophagic degradation of NLRP3 inflammasome in Aβ-, α-synuclein- or mHtt-treated BV-2 cells. • PSS rescue PC-12 cells which were damaged by the over-generated proinflammatory cytokines. • PSS improve cognitive function and ameliorate the pathology in APP/PS mice via activating the SHP-2-mediated mitophagy. [ABSTRACT FROM AUTHOR]

Abstract: Tumor necrosis factor alpha (TNFα) induces necroptosis and autophagy; however, the detailed molecular mechanism is not fully understood. In this study, we found that TNFα administration caused mitochondrial dysfunction and reactive oxygen species (ROS) production, which led to necroptosis and autophagy in murine fibrosarcoma L929 cells. Notably, the RIP1 (serine–threonine kinase receptor-interacting protein 1, a main adaptor protein of necroptosis) specific inhibitor necrostatin-1 (Nec-1) recovered mitochondrial dysfunction and ROS production due to TNFα administration. Moreover, pan-caspase inhibitor z-VAD-fmk (zVAD) increased RIP1 expression and exacerbated TNFα-induced mitochondrial dysfunction and ROS production, indicating that RIP1 led to mitochondrial dysfunction and ROS production. In addition, cytochrome c release from mitochondria was accompanied with TNFα administration, and Nec-1 blocked the release of cytochrome c upon TNFα administration, while zVAD enhanced the release. These further suggested that RIP1 induced mitochondrial dysfunction accompanied with cytochrome c release. Furthermore, autophagy inhibitor 3-methyladenine (3MA) did not affect RIP1 expression as well as mitochondrial dysfunction and ROS production. Together with our previous publication that autophagy was a downstream consequence of necroptosis, we concluded that TNFα induced mitochondrial dysfunction accompanied with ROS production and cytochrome c release via RIP1, leading to necroptosis and resulting autophagic cell death. [Copyright &y& Elsevier]

Enhancing the clearance of proteins associated with Alzheimer's disease (AD) emerges as a promising approach for AD therapeutics. This study explores the potential of Radix Stellariae , a traditional Chinese medicine, in treating AD. Utilizing transgenic C. elegans models of AD, we demonstrated that a 75% ethanol extract of Radix Stellariae (RSE) (at 50 µg/mL) effectively diminishes Aβ and Tau protein expression, and alleviates their induced impairments including paralysis, behavioral dysfunction, neurotoxicity, and ROS accumulation. Additionally, RSE enhances the stress resistance of C. elegans. Further investigations revealed that RSE promotes autophagy, a critical cellular process for protein degradation, in these models. We found that inhibiting autophagy-related genes negated the neuroprotective effects of RSE, suggesting a central role for autophagy in the actions of RSE. In PC-12 cells, we observed that RSE not only inhibited Aβ fibril formation but also promoted the degradation of AD-related proteins and reduced their cytotoxicity. Mechanistically, RSE was found to induce autophagy via modulating PI3K/AKT/mTOR and AMPK/mTOR signaling pathways. Importantly, inhibiting autophagy counteracted the beneficial effects of RSE on the clearance of AD-associated proteins. Moreover, we identified Dichotomine B, a β-carboline alkaloid, as a key active constituent of RSE in mitigating AD pathology in C. elegans at concentrations ranging from 50 to 1000 µM. Collectively, our study presents novel discoveries that RSE alleviates AD pathology and toxicity primarily by inducing autophagy, both in vivo and in vitro. These findings open up new avenues for exploring the therapeutic potential of RSE and its active component, Dichotomine B, in treating neurodegenerative diseases like AD. [Display omitted] • RSE ameliorates AD-related pathology in both C. elegans and cellular models of AD. • RSE induces autophagy via the PI3K/AKT/mTOR and AMPK/mTOR signaling pathways. • RSE protects against AD by activating autophagy pathway in vivo and in vitro. [ABSTRACT FROM AUTHOR]

To validate the mechanism by which miR-21-5p mediates autophagy in drug-resistant cells in hepatocellular carcinoma (HCC), aggravating sorafenib resistance and progression of HCC. HCC cells were treated with sorafenib to establish sorafenib-resistant cells, and nude mice were subcutaneously injected with hepatoma cells to establish animal models. RT–qPCR was used to determine the level of miR-21-5p, and Western blotting was used to determine the level of related proteins. Cell apoptosis, cell migration, the level of LC3 were accessed. Immunohistochemical staining was used for detection of Ki-67 and LC3. A dual-luciferase reporter assay certified that miR-21-5p targets USP42, and a co-immunoprecipitation assay validated the mutual effect between USP24 and SIRT7. miR-21-5p and USP42 were highly expressed in HCC tissue and cells. Inhibition of miR-21-5p or knockdown of USP42 inhibited cell proliferation and cell migration, upregulated the level of E-cadherin, and downregulated the level of vimentin, fibronectin and N-cadherin. Overexpression of miR-21-5p reversed the knockdown of USP42. Inhibition of miR-21-5p downregulated the ubiquitination level of SIRT7, downregulated the levels of LC3II/I ratio and Beclin1, and upregulated the expression of p62. The tumor size in the miR-21-5p inhibitor group was smaller, and Ki-67 and LC3 in tumor tissue were reduced, while the overexpression of USP42 reversed the effect of the miR-21-5p inhibitor. miR-21-5p promotes deterioration and sorafenib resistance in hepatocellular carcinoma by upregulating autophagy levels. Knockdown of miR-21-5p inhibits the development of sorafenib-resistant tumors by USP24-mediated SIRT7 ubiquitination. Schematic model of the mechanism underlying miR-21-5p on sorafenib resistance in HCC. miR-21-5p promotes the deterioration and Sorafenib resistance in hepatocellular carcinoma by upregulating SIRT7-mediating autophagy levels through deubiquitinating enzyme USP24. [Display omitted] [ABSTRACT FROM AUTHOR]

Eukaryotic cells use autophagy to recycle cellular components. During autophagy, autophagosomes deliver cytoplasmic contents to the vacuole or lysosome for breakdown. Mammalian cells regulate the dynamics of autophagy via ubiquitin-mediated proteolysis of autophagy proteins. Here, we show that the Arabidopsis thaliana Tumor necrosis factor Receptor-Associated Factor (TRAF) family proteins TRAF1a and TRAF1b (previously named MUSE14 and MUSE13, respectively) help regulate autophagy via ubiquitination. Upon starvation, cytoplasmic TRAF1a and TRAF1b translocated to autophagosomes. Knockout traf1a/b lines showed reduced tolerance to nutrient deficiency, increased salicylic acid and reactive oxygen species levels, and constitutive cell death in rosettes, resembling the phenotypes of autophagy-defective mutants. Starvation-activated autophagosome accumulation decreased in traf1a/b root cells, indicating that TRAF1a and TRAF1b function redundantly in regulating autophagosome formation. TRAF1a and TRAF1b interacted in planta with ATG6 and the RING finger E3 ligases SINAT1, SINAT2, and SINAT6 (with a truncated RING-finger domain). SINAT1 and SINAT2 require the presence of TRAF1a and TRAF1b to ubiquitinate and destabilize AUTOPHAGY PROTEIN6 (ATG6) in vivo. Conversely, starvation-induced SINAT6 reduced SINAT1- and SINAT2-mediated ubiquitination and degradation of ATG6. Consistently, SINAT1 / SINAT2 and SINAT6 knockout mutants exhibited increased tolerance and sensitivity, respectively, to nutrient starvation. Therefore, TRAF1a and TRAF1b function as molecular adaptors that help regulate autophagy by modulating ATG6 stability in Arabidopsis. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging evidence indicates that the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome is activated, which results in a cytokine storm at the late stage of COVID-19. Autophagy regulation is involved in the infection and replication of SARS-CoV-2 at the early stage and the inhibition of NLRP3 inflammasome-mediated lung inflammation at the late stage of COVID-19. Here, we discuss the autophagy regulation at different stages of COVID-19. Specifically, we highlight the therapeutic potential of autophagy activators in COVID-19 by inhibiting the NLRP3 inflammasome, thereby avoiding the cytokine storm. We hope this review provides enlightenment for the use of autophagy activators targeting the inhibition of the NLRP3 inflammasome, specifically the combinational therapy of autophagy modulators with the inhibitors of the NLRP3 inflammasome, antiviral drugs, or anti-inflammatory drugs in the fight against COVID-19. [Display omitted] • Targeting the NLRP3 inflammasome and its inhibitors for the treatment of COVID-19. • Autophagy regulation and the use of its modulators at different stages of COVID-19 • Targeting the inhibition of NLRP3 inflammasome using autophagy inducers in COVID-19 [ABSTRACT FROM AUTHOR]

• We discussed the key role of microglia and sex differences in NLRP3 inflammasome-mediated neuroinflammation. • We discussed the correlation of the over-activated NLRP3 inflammasome with the pathology of neurodegenerative diseases. • We discussed microglial autophagy and summarized the modulators in NLRP3 inflammasome-mediated neurodegenerative diseases. • The combined use of microglial autophagy inducers with the inhibitors of NLRP3 inflammasome requires further validations. Neuroinflammation is considered as a detrimental factor in neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), etc. Nucleotide-binding oligomerization domain-, leucine-rich repeat- and pyrin domain-containing 3 (NLRP3), the most well-studied inflammasome, is abundantly expressed in microglia and has gained considerable attention. Misfolded proteins are characterized as the common hallmarks of neurodegenerative diseases due to not only their induced neuronal toxicity but also their effects in over-activating microglia and the NLRP3 inflammasome. The activated NLRP3 inflammasome aggravates the pathology and accelerates the progression of neurodegenerative diseases. Emerging evidence indicates that microglial autophagy plays an important role in the maintenance of brain homeostasis and the negative regulation of NLRP3 inflammasome-mediated neuroinflammation. The excessive activation of NLRP3 inflammasome impairs microglial autophagy and further aggravates the pathogenesis of neurodegenerative diseases. In this review article, we summarize and discuss the NLRP3 inflammasome and its specific inhibitors in microglia. The crucial role of microglial autophagy and its inducers in the removal of misfolded proteins, the clearance of damaged mitochondria and reactive oxygen species (ROS), and the degradation of the NLRP3 inflammasome or its components in neurodegenerative diseases are summarized. Understanding the underlying mechanisms behind the sex differences in NLRP3 inflammasome-mediated neurodegenerative diseases will help researchers to develop more targeted therapies and increase our diagnostic and prognostic abilities. In addition, the superiority of the combined use of microglial autophagy inducers with the specific inhibitors of the NLRP3 inflammasome in the inhibition of NLRP3 inflammasome-mediated neuroinflammation requires further preclinical and clinical validations in the future. [ABSTRACT FROM AUTHOR]

• LSP, a bioactive fraction enriching polyphenol from lychee seed, activates autophagy via the LRP1/AMPK-regulated autophagy in BV-2 cells. • LRP1 negatively regulates the NLRP3 inflammasome in Aβ(1-42)-induced BV-2 cells. • LSP inhibits the NLRP3 inflammasome-mediated neuroinflammation in Aβ(1-42)-induced BV-2 cells via the LRP1/AMPK signaling pathway. • LSP improves the cognitive function and inhibits the NLRP3 inflammasome in APP/PS1 mice. Emerging evidence indicates that the enhancement of microglial autophagy inhibits the NLRP3 inflammasome mediated neuroinflammation in Alzheimer's disease (AD). Meanwhile, low density lipoprotein receptor-related protein 1 (LRP1) highly expressed in microglia is able to negatively regulate neuroinflammation and positively regulate autophagy. In addition, we have previously reported that an active lychee seed fraction enriching polyphenol (LSP) exhibits anti-neuroinflammation in Aβ-induced BV-2 cells. However, its molecular mechanism of action is still unclear. In this study, we aim to investigate whether LSP inhibits the NLRP3 inflammasome mediated neuroinflammation and clarify its molecular mechanism in Aβ-induced BV-2 cells and APP/PS1 mice. The results showed that LSP dose- and time-dependently activated autophagy by increasing the expression of Beclin 1 and LC3II in BV-2 cells, which was regulated by the upregulation of LRP1 and its mediated AMPK signaling pathway. In addition, both the Western blotting and fluorescence microscopic results demonstrated that LSP could significantly suppress the activation of NLRP3 inflammasome by inhibiting the expression of NLRP3, ASC, the cleavage of caspase-1, and the release of IL-1β in Aβ(1-42)-induced BV-2 cells. In addition, the siRNA LRP1 successfully abolished the effect of LSP on the activation of AMPK and its mediated autophagy, as well as the inhibition of NLRP3 inflammasome. Furthermore, LSP rescued PC-12 cells which were induced by the conditioned medium from Aβ(1-42)-treated BV-2 cells. Moreover, LSP improved the cognitive function and inhibited the NLRP3 inflammasome in APP/PS1 mice. Taken together, LSP inhibited the NLRP3 inflammasome-mediated neuroinflammation in the in vitro and in vivo models of AD, which was closely associated with the LRP1/AMPK-mediated autophagy. Thus, the findings from this study further provide evidences for LSP serving as a potential drug for the treatment of AD in the future. [ABSTRACT FROM AUTHOR]