Upregulation Of Autophagy Research Articles

Zinc reduces hepatic lipid deposition and activates lipophagy via Zn2+/MTF-1/PPARα and Ca2+/CaMKKβ/AMPK pathways.

Zinc (Zn) deficiency is the most consistently discovered nutritional manifestations of fatty liver disease. Although Zn is known to stimulate hepatic lipid oxidation, little is known about its underlying mechanism of action in lipolysis. Given the potential role of lipophagy in lipid metabolism, the purpose of this study was to test the hypothesis that Zn attenuates hepatic lipid accumulation by modulating lipophagy. The present study indicated that Zn is a potent promoter of lipophagy. Zn administration significantly alleviated hepatocellular lipid accumulation and increased the release of free fatty acids in association with enhanced fatty acid oxidation and inhibited lipogenesis, which was accompanied by activation of autophagy. Moreover, Zn reduced lipid accumulation and stimulated lipolysis by autophagy-mediated lipophagy. Zn-induced up-regulation of autophagy and lipid depletion is free Zn2+-dependent in the cytosols. Zn-induced autophagy and lipid turnover involved up-regulation of the calcium/calmodulin-dependent protein kinase kinase-β (Ca2+/CaMKKβ)/AMPK pathway. Meanwhile, Zn2+-activated autophagy and lipid depletion were via enhancing metal response element-binding transcription factor (MTF)-1 DNA binding at PPARα promoter region, which in turn induced transcriptional activation of the key genes related to autophagy and lipolysis. Zn activated the pathways of Zn2+/MTF-1/ Peroxisome proliferator-activated receptor (PPAR)α and Ca2+/CaMKKβ/AMPK, resulting in the up-regulation of lipophagy and accordingly reduced hepatic lipid accumulation. Our study, for the first time, provided innovative evidence of the direct relationship between metal elements (Zn) and lipid metabolism. The present study also indicated the novel mechanism for Zn-induced lipolysis by the activation of Zn2+/MTF-1/PPARα and Ca2+/CaMKKβ/AMPK pathways, which induced the occurrence of lipophagy. These results provide new insight into Zn nutrition and its potential beneficial effects on the prevention of fatty liver disease in vertebrates.-Wei, C.-C., Luo, Z., Hogstrand, C., Xu, Y.-H., Wu, L.-X., Chen, G.-H., Pan, Y.-X., Song, Y.-F. Zinc reduces hepatic lipid deposition and activates lipophagy via Zn2+/MTF-1/PPARα and Ca2+/CaMKKβ/AMPK pathways.

Exhaustion of mitochondrial and autophagic reserve may contribute to the development of LRRK2G2019S-Parkinson\u2019s disease

BackgroundMutations in leucine rich repeat kinase 2 (LRRK2) are the most common cause of familial Parkinson’s disease (PD). Mitochondrial and autophagic dysfunction has been described as etiologic factors in different experimental models of PD. We aimed to study the role of mitochondria and autophagy in LRRK2G2019S-mutation, and its relationship with the presence of PD-symptoms.MethodsFibroblasts from six non-manifesting LRRK2G2019S-carriers (NM-LRRK2G2019S) and seven patients with LRRK2G2019S-associated PD (PD-LRRK2G2019S) were compared to eight healthy controls (C). An exhaustive assessment of mitochondrial performance and autophagy was performed after 24-h exposure to standard (glucose) or mitochondrial-challenging environment (galactose), where mitochondrial and autophagy impairment may be heightened.ResultsA similar mitochondrial phenotype of NM-LRRK2G2019S and controls, except for an early mitochondrial depolarization (54.14% increased, p = 0.04), was shown in glucose. In response to galactose, mitochondrial dynamics of NM-LRRK2G2019S improved (− 17.54% circularity, p = 0.002 and + 42.53% form factor, p = 0.051), probably to maintain ATP levels over controls. A compromised bioenergetic function was suggested in PD-LRRK2G2019S when compared to controls in glucose media. An inefficient response to galactose and worsened mitochondrial dynamics (− 37.7% mitochondrial elongation, p = 0.053) was shown, leading to increased oxidative stress. Autophagy initiation (SQTSM/P62) was upregulated in NM-LRRK2G2019S when compared to controls (glucose + 118.4%, p = 0.014; galactose + 114.44%, p = 0.009,) and autophagosome formation increased in glucose media. Despite of elevated SQSTM1/P62 levels of PD-NMG2019S when compared to controls (glucose + 226.14%, p = 0.04; galactose + 78.5%, p = 0.02), autophagosome formation was deficient in PD-LRRK2G2019S when compared to NM-LRRK2G2019S (− 71.26%, p = 0.022).ConclusionsEnhanced mitochondrial performance of NM-LRRK2G2019S in mitochondrial-challenging conditions and upregulation of autophagy suggests that an exhaustion of mitochondrial bioenergetic and autophagic reserve, may contribute to the development of PD in LRRK2G2019S mutation carriers.

Nicotinate-Curcumin Stimulates Reverse Cholesterol Transport by Upregulation of Autophagy and LDL Receptor

Nicotinate-Curcumin Stimulates Reverse Cholesterol Transport by Upregulation of Autophagy and LDL Receptor

Meclofenamic Acid Reduces Reactive Oxygen Species Accumulation and Apoptosis, Inhibits Excessive Autophagy, and Protects Hair Cell-Like HEI-OC1 Cells From Cisplatin-Induced Damage.

Hearing loss is the most common sensory disorder in humans, and a significant number of cases is due to the ototoxicity of drugs such as cisplatin that cause hair cell (HC) damage. Thus, there is great interest in finding agents and mechanisms that protect HCs from ototoxic drug damage. It has been proposed that epigenetic modifications are related to inner ear development and play a significant role in HC protection and HC regeneration; however, whether the m6A modification and the ethyl ester form of meclofenamic acid (MA2), which is a highly selective inhibitor of FTO (fatmass and obesity-associated enzyme, one of the primary human demethylases), can affect the process of HC apoptosis induced by ototoxic drugs remains largely unexplored. In this study, we took advantage of the HEI-OC1 cell line, which is a cochlear HC-like cell line, to investigate the role of epigenetic modifications in cisplatin-induced cell death. We found that cisplatin injury caused reactive oxygen species accumulation and increased apoptosis in HEI-OC1 cells, and the cisplatin injury was reduced by co-treatment with MA2 compared to the cisplatin-only group. Further investigation showed that MA2 attenuated cisplatin-induced oxidative stress and apoptosis in HEI-OC1 cells. We next found that the cisplatin-induced upregulation of autophagy was significantly inhibited after MA2 treatment, indicating that MA2 inhibited the cisplatin-induced excessive autophagy. Our findings show that MA2 has a protective effect and improves the viability of HEI-OC1 cells after cisplatin treatment, and they provide new insights into potential therapeutic targets for the amelioration of cisplatin-induced ototoxicity.

Genipin alleviates vascular hyperpermeability following hemorrhagic shock by up-regulation of SIRT3/autophagy

Genipin (GP) is commonly used to treat cardiovascular diseases; however, the protective action of GP against vascular hyperpermeability (VH) has not been reported. We previously reported that intrinsic apoptotic signaling (IAS) is involved in VH following hemorrhagic shock (HS). GP inhibits apoptosis, but the specific mechanism remains unclear. In the present study, we observed that GP protects against HS-induced VH in vitro and in vivo. We report that this protective effect is related to the inhibition of IAS by up-regulation of autophagy via sirtuin 3 (SIRT3). The endothelial cell hyperpermeability induced by HS was enhanced by GP; this was attenuated by 3-methyladenine (3MA), a specific inhibitor of autophagy, indicating the involvement of autophagy. Consistent with these results, we found that 3MA reversed the effects of GP on up-regulation of autophagy, and also diminished the protective effect of GP against IAS activation following HS. Furthermore, knockout of SIRT3 inhibited GP-induced autophagy, indicating the requirement of SIRT3 in the regulation of autophagy by GP. In rats, GP improved HS-induced VH, which was repressed by 3MA and 3-(1H-1,2,3-triazol-4-yl)pyridine (3-TYP), a SIRT3 inhibitor. In conclusion, these findings suggest that autophagy plays a protective effect in VH following HS; the protective effect of autophagy is reinforced by GP, which protects against IAS and VH by up-regulating SIRT3.

Interpenetrating polymer network scaffold of sodium hyaluronate and sodium alginate combined with berberine for osteochondral defect regeneration

Degradation of the articular cartilage and structural remodeling of the subchondral bone are regarded as the two major pathological characteristics of osteoarthritis. This study aimed to investigate the effect of an interpenetrating polymer network (IPN) of a sodium hyaluronate and sodium alginate (HA/SA) scaffold combined with berberine (BER) on osteochondral repair. We first developed an IPN scaffold of HA/SA and evaluated its characteristics. Then, we analyzed the effect of the HA/SA scaffold combined with BER on the healing of osteochondral defects in vivo. Finally, we explored the mechanism of this system in osteochondral repair. The results showed that the system could simultaneously regenerate not only the cartilage but also the subchondral bone. Our results also revealed that the subchondral bone was partially repaired by activating the Wnt signaling pathway and the cartilage was protected from degeneration by the upregulation of autophagy. This study demonstrated that the combination of the IPN scaffold of HA/SA and BER is a promising strategy for the osteochondral defect regeneration.

Autophagy in Age-Associated Neurodegeneration.

The elimination of abnormal and dysfunctional cellular constituents is an essential prerequisite for nerve cells to maintain their homeostasis and proper function. This is mainly achieved through autophagy, a process that eliminates abnormal and dysfunctional cellular components, including misfolded proteins and damaged organelles. Several studies suggest that age-related decline of autophagy impedes neuronal homeostasis and, subsequently, leads to the progression of neurodegenerative disorders due to the accumulation of toxic protein aggregates in neurons. Here, we discuss the involvement of autophagy perturbation in neurodegeneration and present evidence indicating that upregulation of autophagy holds potential for the development of therapeutic interventions towards confronting neurodegenerative diseases in humans.

IL-33/ST2L Signaling Provides Neuroprotection Through Inhibiting Autophagy, Endoplasmic Reticulum Stress, and Apoptosis in a Mouse Model of Traumatic Brain Injury.

Interleukin-33 (IL-33) is a member of the interleukin-1 (IL-1) cytokine family and an extracellular ligand for the orphan IL-1 receptor ST2. Accumulated evidence shows that the IL-33/ST2 axis plays a crucial role in the pathogenesis of central nervous system (CNS) diseases and injury, including traumatic brain injury (TBI). However, the roles and molecular mechanisms of the IL-33/ST2 axis after TBI remain poorly understood. In this study, we investigated the role of IL-33/ST2 signaling in mouse TBI-induced brain edema and neurobehavioral deficits, and further exploited underlying mechanisms, using salubrinal (SAL), the endoplasmic reticulum (ER) stress inhibitor and anti-ST2L. The increase in IL-33 level and the decrease in ST2L level at injured cortex were first observed at 24 h post-TBI. By immunofluorescent double-labeled staining, IL-33 co-localized in GFAP-positive astrocytes, and Olig-2-positive oligodendrocytes, and predominantly presented in their nucleus. Additionally, TBI-induced brain water content, motor function outcome, and spatial learning and memory deficits were alleviated by IL-33 treatment. Moreover, IL-33 and SAL alone, or their combination prevented TBI-induced the increase of IL-1β and TNF-α levels, suppressed the up-regulation of ER stress, apoptosis and autophagy after TBI. However, anti-ST2L treatment could significantly invert the above effects of IL-33. Together, these data demonstrate that IL-33/ST2 signaling mitigates TBI-induced brain edema, motor function outcome, spatial learning and memory deficits, at least in part, by a mechanism involving suppressing autophagy, ER stress, apoptosis and neuroinflammation.

The NLRP3-Caspase 1 Inflammasome Negatively Regulates Autophagy via TLR4-TRIF in Prion Peptide-Infected Microglia.

Prion diseases are neurodegenerative disorders characterized by the accumulation of misfolded prion protein, spongiform changes in the brain, and brain inflammation as a result of the wide-spread activation of microglia. Autophagy is a highly conserved catabolic process for the clearance of cytoplasmic components, including protein aggregates and damaged organelles; this process also eliminates pathological PrPSc as it accumulates during prion infection. The NALP3 inflammasome is a multiprotein complex that is a component of the innate immune system and is responsible for the release of pro-inflammatory cytokines. Our previous study showed that the neurotoxic prion peptide PrP106-126 induces NALP3 inflammasome activation and subsequent IL-1β release in microglia. Autophagy is involved in the regulation of the immune responses and inflammation in many diseases including neurodegenerative diseases. However, the relationship between autophagy and NALP3 inflammasome in prion diseases has not been investigated. In this study, we demonstrated that the processing and release of mature IL-1β is significantly enhanced by the inhibition of autophagy. Conversely, gene-silencing of the NALP3 inflammasome promotes autophagy. Suppression of TRIF or TLR4 by siRNA attenuated PrP106-126-induced autophagy, which is indicating that the TLR4-TRIF signaling pathway is involved in PrP106-26-induced autophagy. Caspase 1 directly cleaved TRIF to diminish TLR-4-TRIF mediated autophagy. Our findings suggest that the inhibition of autophagy by NALP3 inflammasome is probably mediated by activated Caspase-1-induced TRIF cleavage. This is the first study reporting that the NALP3 inflammasome complex negatively regulates autophagy in response to PrP106-126 stimulation in microglia, and partly explains the mechanism of autophagy inhibition by Caspase-1 in PrP106-126-induced BV2 cell activation. Our findings suggest that autophagy up-regulation and inhibition of Caspase-1 may protect against prion-induced neuroinflammation and accelerate misfolded protein degradation and are potential therapeutic approaches for prion diseases.

Valproic Acid Attenuates Traumatic Brain Injury-Induced Inflammation in Vivo: Involvement of Autophagy and the Nrf2/ARE Signaling Pathway.

Microglial activation and the inflammatory response in the central nervous system (CNS) play important roles in secondary damage after traumatic brain injury (TBI). Transcriptional activation of genes that limit secondary damage to the CNS are mediated by a cis-acting element called the antioxidant responsive element (ARE). ARE is known to associate with the transcription factor NF-E2-related factor 2 (Nrf2), a transcription factor that is associated with histone deacetylases (HDACs). This pathway, known as the Nrf2/ARE pathway, is a critical antioxidative factor pathway that regulates the balance of oxygen free radicals and the inflammatory response, and is also related to autophagic activities. Although valproic acid (VPA) is known to inhibit HDACs, it is unclear whether VPA plays a role in the microglia-mediated neuroinflammatory response after TBI via regulating oxidative stress and autophagy induced by the Nrf2/ARE signaling pathway. In this study, we demonstrate that microglial activation, oxidative stress, autophagy, and the Nrf2/ARE signaling pathway play essential roles in secondary injury following TBI. Treatment with VPA alleviated TBI-induced secondary brain injury, including neurological deficits, cerebral edema, and neuronal apoptosis. Moreover, VPA treatment upregulated the occurrence of autophagy and Nrf2/ARE pathway activity after TBI, and there was an increase in H3, H4 histone acetylation levels, accompanied by decreased transcriptional activity of the HDAC3 promoter in cortical lesions. These results suggest that VPA-mediated up-regulation of autophagy and antioxidative responses are likely due to increased activation of Nrf2/ARE pathway, through direct inhibition of HDAC3. This inhibition further reduces TBI-induced microglial activation and the subsequent inflammatory response, ultimately leading to neuroprotection.

Hydrogen Sulfide Regulating Myocardial Structure and Function by Targeting Cardiomyocyte Autophagy.

Objective:Hydrogen sulfide (H2S), a gaseous signal molecule, plays a crucial role in many pathophysiologic processes in the cardiovascular system. Autophagy has been shown to participate in the occurrence of many cardiac diseases. Increasing evidences indicated that H2S regulates myocardial structure and function in association with the altered autophagy and plays a “switcher” role in the autophagy of myocardial diseases. The aim of this review was to summarize these insights and provide the experimental evidence that H2S targets cardiomyocyte autophagy to regulate cardiovascular function.Data Sources:This review was based on data in articles published in the PubMed databases up to October 30, 2017, with the following keywords: “hydrogen sulfide,” “autophagy,” and “cardiovascular diseases.”Study Selection:Original articles and critical reviews on H2S and autophagy were selected for this review.Results:When autophagy plays an adaptive role in the pathogenesis of diseases, H2S restores autophagy; otherwise, when autophagy plays a detrimental role, H2S downregulates autophagy to exert a cardioprotective function. For example, H2S has beneficial effects by regulating autophagy in myocardial ischemia/reperfusion and plays a protective role by inhibiting autophagy during the operation of cardioplegia and cardiopulmonary bypass. H2S postpones cardiac aging associated with the upregulation of autophagy but improves the left ventricular function of smoking rats by lowering autophagy.Conclusions:H2S exerts cardiovascular protection by regulating autophagy. Cardiovascular autophagy would likely become a potential target of H2S therapy for cardiovascular diseases.

Reconstitution of Autophagy Improves Vascular Reactivity in Spontaneously Hypertensive Rats

The accumulation of misfolded‐aggregated proteins is linked to an increasing number of degenerative diseases, including hypertension. Although protein damage and misfolding are an inevitable consequence of normal cellular function, multiple proteostasis mechanisms are devoted to the repair or clearance of damaged proteins in order to prevent proteotoxicity. Autophagy is the constitutive and basally active recycling mechanism responsible for protein quality control. Previously, our data has suggested decreased autophagy in conduit and resistance arteries from spontaneously hypertensive rats (SHR); however, direct measurement of autophagic activity, as well as the proteotoxic consequences of undegraded, misfolded protein has not been performed. Furthermore, the effects of reconstituting autophagic activity on vascular reactivity are currently unknown. We hypothesized that mesenteric resistance arteries (MRA) from adult (14 weeks old) SHR would have decreased autophagic activity in lysosomes extracted from arteries and this would be associated with increased misfolded protein oligomers. Therefore, we further hypothesized that upregulation of autophagy via mammalian target of rapamycin (mTOR) inhibition would decrease contraction and improve relaxation in isolated MRA from SHR mounted on wire myographs. We observed that the activity of acid phosphatase, the major acid hydrolase in lysosomes, from arterial lysosomes (pooled mesenteric arteries and aorta) was decreased in SHR (μmol/min, Wistar: 0.51±0.06 vs. SHR: 0.24±0.02, p<0.05). This diminished arterial autophagic activity was observed in conjunction with the increased presence of insoluble protein deposition. Specifically, SHR MRA contained increased fibrillar amyloid oligomers, especially along the endothelium monolayer, as indicated by Congo red staining (Figure 1). When autophagy was reconstituted in isolated MRA via mTOR inhibition with Everolimus (EV; first generation mTOR inhibitor) for 1 hr, we observed that the maximum contraction to phenylephrine was reduced [Emax (mN), Vehicle: 19.8±0.5 vs. EV (0.1 nM): 10.7±0.5 vs. EV (0.1 μM): 8.5±1.0, p<0.05] and the contraction to high concentrations acetylcholine was prevented [LogEC50, Vehicle: −6.9±0.1 vs. EV (0.1 nM): −9.2±0.4 vs. EV (0.1 μM): −8.2±0.1, p<0.05]. Overall, these data reveal that SHR have impaired arterial lysosomal activity and this is associated with the accumulation of misfolded proteins. As a result, reconstituting arterial autophagic activity improved vascular function and could be a novel therapeutic treatment for proteotoxicity in hypertension.Support or Funding InformationNIH (K99GM118885 and P01HL134604).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

MP64-13 COMBINED N-TERMINAL ANDROGEN RECEPTOR AND AUTOPHAGY INHIBITION INCREASES THE ANTI-TUMOR EFFECT IN ENZALUTAMIDE-SENSITIVE AND ENZALUTAMIDE-RESISTANT LNCAP CELLS

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology II1 Apr 2018MP64-13 COMBINED N-TERMINAL ANDROGEN RECEPTOR AND AUTOPHAGY INHIBITION INCREASES THE ANTI-TUMOR EFFECT IN ENZALUTAMIDE-SENSITIVE AND ENZALUTAMIDE-RESISTANT LNCAP CELLS Benedikt Kranzbühler, Souzan Salemi, Tullio Sulser, and Daniel Eberli Benedikt KranzbühlerBenedikt Kranzbühler More articles by this author , Souzan SalemiSouzan Salemi More articles by this author , Tullio SulserTullio Sulser More articles by this author , and Daniel EberliDaniel Eberli More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2058AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Multiple androgen receptor (AR) dependent and independent resistance mechanisms limit the efficacy of current castration resistant prostate cancer (CRPC) treatment. Novel N-terminal domain (NTD) binding AR targeting components including EPI-001 have the promising ability to block constitutively active splice variants; a major resistance mechanism in CRPC. Autophagy is a conserved lysosomal degradation pathway and acts as survival mechanism in cells exposed to anti-cancer treatment. We hypothesized that also a promising NTD-AR treatment may lead to up-regulation of autophagy and can be targeted by a combination treatment with autophagy inhibitors. METHODS Prostate cancer cell lines LNCaP and LNCaP-EnzR were cultured in steroid-free medium and treated with different concentrations of EPI-001 (EPI: 10, 25, 50uM) and in combination with autophagy inhibitors chloroquine (CHQ, 20uM) or 3-methyladenine (3MA, 5mM). Cell growth was assessed by WST-1-assays after 1 and 7 days. Etidium bromide and AnnexinV were used to measure viability and apoptosis on day 7 after treatment. Autophagosome increase was detected by Autodot staining. In addition, autophagic activity was monitored by western blot (WB) and immunocytochemistry for the expression of LC3-I/II, Atg5 and Beclin1. RESULTS Treatment with EPI resulted in a dose dependent reduction of cell growth and increase of apoptosis on day 7 in both cell lines. Combination of 25uM EPI with autophagy inhibitors led to a further reduction of cell viability up to 17% for CHQ, 15% for 3MA in LNCaP and up to 24% for CHQ, 36% for 3MA in LNCaP-EnzR. Assessment of autophagy levels in EPI treated cells by WB showed an increase of LC3-II and no change in Beclin1 expression in both cell lines. Immunocytochemistry detected a significant increase of Atg5 and pronounced LC3-II punctuation in EPI-001 treated LNCaP and LNCaP-EnzR. This was supported by an increase in autophagosome punctuation observed by Autodot staining. CONCLUSIONS Our data demonstrate that N-terminal androgen receptor inhibition with EPI-001 leads to increased autophagic activity in LNCaP and LNCaP-EnzR prostate cancer cells. Combination of N-terminal androgen receptor blockage with simultaneous autophagy inhibition increases the antitumor effect of EPI even in enzalutamide-resistant cells. Double treatment may offer a promising strategy to overcome resistance mechanisms in advanced prostate cancer. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e855 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Benedikt Kranzbühler More articles by this author Souzan Salemi More articles by this author Tullio Sulser More articles by this author Daniel Eberli More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Invariant BECN1 C‐x‐x‐C Motifs Are Essential For Starvation‐Induced Autophagy

Autophagy is an essential catabolic cellular homeostasis process conserved in all eukaryotes. BECN1, a protein essential for autophagosome nucleation, contains two invariant C‐x‐x‐C motifs (18CxxC21 and 137CxxC140 in human BECN1) that bookend a large BECN1 intrinsically disordered region (IDR). We use circular dichroism spectroscopy to elucidate differences in secondary structural content of the wild‐type and CysTetrad mutant BECN1 IDR. Additionally, we are using small angle X‐ray scattering analyses to further understand the impact of the CysTetrad mutation on the structure of the BECN1 IDR. We also show that helicity of the BECN1 IDR increases upon addition of 2,2,2‐trifluoroethanol (TFE), suggesting that it may undergo binding‐associated helical transitions. Further, we use ICP‐MS to demonstrate that BECN1 binds Zn2+ in a 1:1 molar ratio under both, reducing and non‐reducing environments. Lastly, we show that both C‐x‐x‐C motifs are required, while the IDR is also important, for starvation‐triggered up‐regulation of autophagy.Support or Funding InformationNIH grants RO3 NS090939 and R15 GM122035 (S.C.S.)National Science Foundation grant MCB‐1413525 (S.C.S.)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Association of exercise-induced autophagy upregulation and apoptosis suppression with neuroprotection against pharmacologically induced Parkinson's disease.

[Purpose]We investigated whether treadmill exercise (TE)-induced neuroprotection was associated with enhanced autophagy and reduced apoptosis in a mouse model of pharmacologically induced Parkinson's disease (PD).[Methods]PD was induced via the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). C57BL/6 male mice were randomly assigned to the following three groups: control (C57BL, n=10), MPTP with probenecid (MPTP/C, n=10), and MPTP/ C plus exercise (MPTP-TE, n=10). The MPTP-TE mice performed TE training (10 m/min, 60 min/day, 5 days/week) for 8 weeks. The rotarod test was used to assess motor function.[Results]TE restored MPTP/P-induced motor dysfunctionand increased tyrosine hydroxylase levels. Furthermore, TE diminished the levels of α-synuclein (α-syn), a neurotoxin; modulated the levels of autophagy-associated proteins, including microtubule-associated protein 1 light chain 3-II, p62, BECLIN1, BNIP3, and lysosomal-associated membrane protein-2, which enhanced autophagy; inhibited the activation of proapoptotic proteins (caspase-3 and BAX);and upregulated BCL-2, an antiapoptosis protein.[Conclusion]Taken together, these results suggested that the TE-induced neuroprotection against MPTP-induced cell death was associated with enhanced autophagy and neuronal regeneration based on the findings of inhibited proapoptotic events in the brains of the TE-trained animals.

RET-mediated autophagy suppression as targetable co-dependence in acute myeloid leukemia.

Many cases of AML are associated with mutational activation of receptor tyrosine kinases (RTKs) such as FLT3. However, RTK inhibitors have limited clinical efficacy as single agents, indicating that AML is driven by concomitant activation of different signaling molecules. We used a functional genomic approach to identify RET, encoding an RTK, as an essential gene in multiple subtypes of AML, and observed that AML cells show activation of RET signaling via ARTN/GFRA3 and NRTN/GFRA2 ligand/co-receptor complexes. Interrogation of downstream pathways identified mTORC1-mediated suppression of autophagy and subsequent stabilization of leukemogenic drivers such as mutant FLT3 as important RET effectors. Accordingly, genetic or pharmacologic RET inhibition impaired the growth of FLT3-dependent AML cell lines and was accompanied by upregulation of autophagy and FLT3 depletion. RET dependence was also evident in mouse models of AML and primary AML patient samples, and transcriptome and immunohistochemistry analyses identified elevated RET mRNA levels and co-expression of RET and FLT3 proteins in a substantial proportion of AML patients. Our results indicate that RET-mTORC1 signaling promotes AML through autophagy suppression, suggesting that targeting RET or, more broadly, depletion of leukemogenic drivers via autophagy induction provides a therapeutic opportunity in a relevant subset of AML patients.

Hypoxia-inducible factor-1α-dependent autophagy plays a role in glycolysis switch in mouse granulosa cells.

Autophagy is an essential cellular mechanism that degrades cytoplasmic proteins and organelles to recycle their components. Here we showed that autophagy was essential for the glycolysis switch and energy homeostasis in mouse granulosa cells under hypoxic condition. Our data indicated that hypoxia inducible factor-1α (HIF-1α) could be largely increased in developing follicles and this remarkable upregulation of HIF-1α triggered cell autophagy and glucose uptake. We found that blocking autophagy by Atg7 knockdown and 3-methyladenine (3-MA) treatment affected the glucose metabolism, with increased glycolytic enzyme activity and decreased ATP production. We also found enhanced lactate level, which was harmful to granulosa cells and could induce cell apoptosis. Thus, our findings highlight a protective role of HIF-1α-dependent autophagy for the granulosa cell glycolysis switch in both energy supply and cell survival.

Cyclosporin A induces autophagy in cardiac fibroblasts through the NRP-2/WDFY-1 axis

Cyclosporin A (CsA) is an effective immunosuppressive agent, but its myocardial toxicity limits its widespread and long-term clinical application. In this study, CsA treatment led to damages in myocardial fiber structure, an increase in myocardial fibrosis, and changes in heart size and shape; moreover, the degree of damage was exacerbated with prolonged drug application and increases in dose. However, the mechanism is not clear; therefore, the purpose of this study was to reveal the mechanism of CsA-induced myocardial fibrosis and identify a new target for the prevention and treatment of CsA-induced myocardial injury. Cardiac fibroblasts were treated with CsA (5, 10, or 20 μg/mL) for 24 h. Autophagy was observed by electron microscopy and immunofluorescence. The expression of NRP-2/WDFY-1, autophagy-related proteins (Beclin1 and LC3B), fibrosis-related proteins (MMP2/9), and fibroblast phenotype conversion factor (α-SMA) was evaluated by Western blot. The expression of collagen I was determined by ELISA. Then, we used the gene interference technique to alter WDFY-1 expression with or without CsA or 3-MA treatment for 24 h, and the effects on autophagy and the expression of autophagy-related proteins, fibrosis-associated proteins, IFN-α, TNF-α, and IL-6 were determined. The results showed the following: (1) CsA induced fibrosis-related protein (MMP2/9), fibroblast phenotype conversion factor (α-SMA), and collagen I up-regulation in a dose-dependent manner. (2) CsA induced the formation of autophagosomes and up-regulated the expression of Beclin1, LC3B, and the ERK/MAPK pathway in cardiac fibroblasts. (3) CsA induced NRP-2 down-regulation and WDFY-1 up-regulation. (4) Depletion of WDFY-1 inhibited CsA-induced autophagy, TNF-α and IFN-α up-regulation, and fibrosis. (5) The autophagy inhibitor 3-MA inhibited CsA-induced TNF-α and IFN-α up-regulation and fibrosis. Overall, cyclosporin A induces autophagy in cardiac fibroblasts through the NRP-2/WDFY-1 axis, which promotes the progression of myocardial fibrosis.

Autophagy is essential for the maintenance of amino acids and ATP levels during acute amino acid starvation in MDAMB231 cells.

The results obtained in this study helps to expand our current knowledge on how cells respond to environmental changes; the biochemical and metabolic consequences and the physiological processes activated in response. The environmental stress applied in this study is relevant to tumour physiology, and results can be translated to cancer therapeutic and clinical research areas, ultimately assisting in the specific targeting of cancer cells while avoiding harm to normal cells.

Arresting frailty and sarcopenia in cirrhosis: Future prospects.

Arresting frailty and sarcopenia in cirrhosis: Future prospects.