ω-6 Polyunsaturated fatty acids (linoleic acid) activate both autophagy and antioxidation in a synergistic feedback loop via TOR-dependent and TOR-independent signaling pathways

Abstract ω-6 Polyunsaturated fatty acids (PUFAs) are essential fatty acids that participate in macroautophagy (hereafter referred to as autophagy) and the Kelch ECH-associating protein 1 (Keap1)—nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant system in organisms. However, the molecular mechanisms by which ω-6 PUFAs (linoleic acid) regulate autophagy and Keap1–Nrf2 antioxidant system are not completely understood. Therefore, the purposes of this study were to explore the molecular mechanisms by which ω-6 PUFAs (linoleic acid) regulate autophagy and antioxidant system and to investigate the potential relationship between autophagy and antioxidant system through transcriptomic analysis, quantitative real-time polymerase chain reaction (RT-qPCR), western blot analysis, coimmunoprecipitation (Co-IP) and electrophoretic mobility shift assays (EMSAs) in vivo and in vitro. The results of the present study indicated that ω-6 PUFAs in diets induced autophagy but decrease antioxidant ability in vivo. However, the results also provided evidence, for the first time, that ω-6 PUFAs (linoleic acid) induced autophagy and increased antioxidant ability through the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway and the AMPK-target of rapamycin (TOR) signaling pathway in hepatocytes in vitro. Interestingly, the findings revealed a ω-6 PUFA-induced synergistic feedback loop between autophagy and antioxidant system, which are connected with each other through the P62 and Keap1 complex. These results suggested that ω-6 PUFAs (linoleic acid) could be useful for activating a synergistic feedback loop between autophagy and antioxidant system and could greatly aid in the prevention and treatment of multiple pathologies.

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The effect of a diet supplemented with the n-6 polyunsaturated fatty acid linoleic acid on prostaglandin production in early- and late-pregnant ewes

Journal of Endocrinology ◽

10.1677/joe.1.05910 ◽

2005 ◽

Vol 184 (1) ◽

pp. 165-178 ◽

Cited By ~ 16

Author(s):

Z Cheng ◽

M Elmes ◽

S E Kirkup ◽

E C Chin ◽

D R E Abayasekara ◽

...

Keyword(s):

Fatty Acids ◽

Linoleic Acid ◽

Polyunsaturated Fatty Acids ◽

Calcium Ionophore ◽

Late Gestation ◽

Major Constituent ◽

Protein Levels ◽

Pg Release

Polyunsaturated fatty acids derived from the diet are incorporated into cell membranes where they act as precursors for prostaglandin (PG) synthesis. Linoleic acid (LA; 18:2 n-6) is a major constituent of plant oils and its consumption in Westernized populations is increasing. This study investigated the influence of LA on PG production by the uterus and placenta. Pregnant ewes were fed a control or an LA-enriched diet. Oxytocin (OT) was injected on day 45 (early) or day 133 (late) of gestation to measure the release of 13,14-dihydro-15-keto PGF2α (PGFM). Ewes were killed on day 46 or day 138 for collection of uterine intercaruncular endometrium and fetal allantochorion. Basal and stimulated PG release from explant cultures was assessed before and after in vitro treatment with OT, lipopolysaccharide (LPS), dexamethasone (DEX) or calcium ionophore (CaI). Expression of cyclooxygenase (COX)-1 and COX-2 was determined by Western blot in endometrium of late-gestation ewes. Circulating PGFM levels in vivo did not differ according to diet but there were highly significant differences in the release of PGs in vitro. Basal production of PGF2αand PGE2 by the endometrium and of PGE2 by the allantochorion were all higher in tissues from LA-supplemented ewes. Endometrial tissues produced more PG following OT and CaI treatment, whereas DEX inhibited production of both PGs at both stages of gestation. In allantochorion collected at day 46 LPS did not significantly alter PGE2 release and DEX increased output, whereas at day 138 LPS was stimulatory but DEX was inhibitory. These data show that a high-LA diet can significantly increase the ability of both endometrium and placental tissues to produce PGs in vitro. This effect of diet may only become apparent after a sustained period of PG release, so was not seen following the brief pulse caused by OT treatment in vivo. As COX protein levels were unaltered, the main influence was likely to be via conversion of LA to arachidonic acid, providing an increased supply of precursor. These results support previous studies which suggest that alterations in dietary polyunsaturated fatty acids may influence the time of labour.

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DEPTOR Deficiency-Mediated mTORc1 Hyperactivation in Vascular Endothelial Cells Promotes Angiogenesis

Cellular Physiology and Biochemistry ◽

10.1159/000488619 ◽

2018 ◽

Vol 46 (2) ◽

pp. 520-531 ◽

Cited By ~ 7

Author(s):

Yan Ding ◽

Lanlan Shan ◽

Wenqing Nai ◽

Xiaojun Lin ◽

Ling Zhou ◽

...

Keyword(s):

Endothelial Cells ◽

Signaling Pathway ◽

Molecular Mechanisms ◽

Gene Knockout ◽

Umbilical Vein ◽

Vascular Endothelial Cell ◽

Tube Formation ◽

Vascular Endothelial

Background/Aims: The mechanistic target of rapamycin (mTOR) signaling pathway is essential for angiogenesis and embryonic development. DEP domain-containing mTOR-interacting protein (DEPTOR) is an mTOR binding protein that functions to inhibit the mTOR pathway In vitro experiments suggest that DEPTOR is crucial for vascular endothelial cell (EC) activation and angiogenic responses. However, knowledge of the effects of DEPTOR on angiogenesis in vivo is limited. This study aimed to determine the role of DEPTOR in tissue angiogenesis and to elucidate the molecular mechanisms. Methods: Cre/loxP conditional gene knockout strategy was used to delete the Deptor gene in mouse vascular ECs. The expression or distribution of cluster of differentiation 31 (CD31), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1 alpha (HIF-1α) were detected by immunohistochemical staining or western blot. Tube formation assay was used to measure angiogenesis in vitro. Results: Deptor knockdown led to increased expression of CD31, VEGF and HIF-1α in heart, liver, kidney and aorta. After treatment with rapamycin, their expression was significantly down regulated. In vitro, human umbilical vein endothelial cells (HUVECs) were transfected with DEPTOR-specific small interfering RNA (siRNA), which resulted in a significant increase in endothelial tube formation and migration rates. In contrast, DEPTOR overexpression markedly reduced the expression of CD31, VEGF and HIF-1α. Conclusions: Our findings demonstrated that deletion of the Deptor gene in vascular ECs resulted in upregulated expression of CD31 and HIF-1α, and further stimulated the expression of VEGF which promoted angiogenesis, indicating that disruption of normal angiogenic pathways may occur through hyperactivation of the mTORC1/HIF-1α/VEGF signaling pathway.

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EBV encoded miRNA BART8-3p promotes radioresistance in nasopharyngeal carcinoma by regulating ATM/ATR signaling pathway

Bioscience Reports ◽

10.1042/bsr20190415 ◽

2019 ◽

Vol 39 (9) ◽

Cited By ~ 6

Author(s):

Xiaohan Zhou ◽

Jialing Zheng ◽

Ying Tang ◽

Yanling lin ◽

Lingzhi Wang ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Signaling Pathway ◽

Ataxia Telangiectasia ◽

Molecular Mechanisms ◽

Radiation Treatment ◽

Ataxia Telangiectasia Mutated ◽

Barr Virus ◽

Radiotherapy Resistance

Abstract Resistance to radiotherapy is one of the main causes of treatment failure in patients with nasopharyngeal carcinoma (NPC). Epstein-Barr virus (EBV) infection is an important factor in the pathogenesis of NPC, and EBV-encoded microRNAs (miRNAs) promote NPC progression. However, the role of EBV-encoded miRNAs in the radiosensitivity of NPC remains unclear. Here, we investigated the effects of EBV-miR-BART8-3p on radiotherapy resistance in NPC cells in vitro and in vivo, and explored the underlying molecular mechanisms. Inhibitors of ataxia telangiectasia mutated (ATM)/ataxia telangiectasia mutated and Rad3-related (ATR) (KU60019 and AZD6738, respectively) were used to examine radiotherapy resistance. We proved that EBV-miR-BART8-3p promoted NPC cell proliferation in response to irradiation in vitro and associated with the induction of cell cycle arrest at the G2/M phase, which was a positive factor for the DNA repair after radiation treatment. Besides, EBV-miR-BART8-3p could increase the size of xenograft tumors significantly in nude mice. Treatment with KU60019 or AZD6738 increased the radiosensitivity of NPC by suppressing the expression of p-ATM and p-ATR. The present results indicate that EBV-miR-BART8-3p promotes radioresistance in NPC by modulating the activity of ATM/ATR signaling pathway.

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In vitro and in vivo inhibition of renin by fatty acids.

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1978.234.6.e593 ◽

1978 ◽

Vol 234 (6) ◽

pp. E593 ◽

Cited By ~ 1

Author(s):

T A Kotchen ◽

W J Welch ◽

R T Talwalkar

Keyword(s):

Blood Pressure ◽

Fatty Acids ◽

Linoleic Acid ◽

Angiotensin Ii ◽

Neutral Lipids ◽

Pressor Response ◽

Arterial Blood ◽

Arachidonic Acids

Circulating neutral lipids inhibit the in vitro renin reaction. To identify the inhibitor(s), free fatty acids were added to human renin and homologous substrate. Capric, lauric, palmitoleic, linoleic, and arachidonic acids each inhibited the rate of angiotensin I production in vitro (P less than 0.01). Inhibition by polysaturated fatty acids (linoleic and arachidonic) was less (P less than 0.01) after catalytic hydrogenation of the double bonds. To evaluate an in vivo effect of renin inhibition intra-arterial blood pressure responses to infusions of renin and angiotensin II (5.0 microgram) were measured in anephric rats (n = 6) before and after infusion of linoleic acid (10 mg iv). Mean increase of blood pressure to angiotensin II before (75 mmHg +/- 9) and after (90 +/- 12) linoleic acid did not differ (P greater than 0.05). However, the pressor response to renin after linoleic acid (18 +/- 3) was less (P less than 0.00)) than that before (102 +/- 13). In summary, several fatty acids inhibit the in vitro renin reaction, and in part inhibition is dependent on unsaturation. Linoleic acid also inhibits the in vivo pressor response to renin. These results suggest that fatty acids may modify the measurement of plasma renin activity and may also affect angiotensin production in vivo.

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n-3 polyunsaturated fatty acids abrogate mTORC1/2 signaling and inhibit adrenocortical carcinoma growth in vitro and in vivo

Oncology Reports ◽

10.3892/or.2016.4720 ◽

2016 ◽

Vol 35 (6) ◽

pp. 3514-3522 ◽

Cited By ~ 6

Author(s):

JUN LIU ◽

MEINIAN XU ◽

YONGBIN ZHAO ◽

CHUNPING AO ◽

YUKUN WU ◽

...

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Adrenocortical Carcinoma

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Role of Omega-3 Polyunsaturated Fatty Acids in the Production of Prostaglandin E2and Nitric Oxide during Experimental Murine Paracoccidioidomycosis

BioMed Research International ◽

10.1155/2013/947687 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

S. C. Sargi ◽

M. M. O. Dalalio ◽

A. G. Moraes ◽

J. E. L. Visentainer ◽

D. R. Morais ◽

...

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Peritoneal Macrophages ◽

Omega 3 Fatty Acids ◽

Omega 3 ◽

Potential Health ◽

Macrophage Activity ◽

Experimental Paracoccidioidomycosis

There has recently been increased interest in the potential health effects of omega-3 polyunsaturated fatty acids on the immune system. Paracoccidioidomycosis is the most important endemic mycosis in Latin America. Macrophages have a fundamental role and act as first line of organism defense. The purpose of this study was to analyze the effect of n-3 fatty acids on the production of PGE2and NO by mice infected with Pb18 and fed a diet enriched with LNA for 8 weeks. To study the effect of omega-3 fatty acids on macrophage activity during experimental paracoccidioidomycosis, mice were infected with Pb18 and fed a diet supplemented with LNA. PGE2in the serum of animals was analyzed and NO in the supernatants of macrophages cultured and challengedin vitrowith Pb18 was measured. Omega-3 fatty acids seemed to decrease the production of PGE2in vivoin the infected group fed an LNA-supplemented diet during the 4th and 8th weeks of the experiment. At the same time, we observed an increase in synthesis of NO by peritoneal macrophages in this group. Omega-3 fatty acids thus appear to have an immunomodulatory effect in paracoccidioidomycosis.

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Cyclin D3-CDK6 Complex Facilitates Tumorigenesis by Regulating the C-Myc/miR-15a/16 Axis in a Feedback Loop in Gastric Cancer

10.21203/rs.3.rs-125333/v1 ◽

2020 ◽

Author(s):

Yeting Hong ◽

Wei He ◽

Jianbin Zhang ◽

Lu Shen ◽

Chong Yu ◽

...

Keyword(s):

Gastric Cancer ◽

Cell Cycle ◽

Cell Proliferation ◽

Feedback Loop ◽

Cell Cycle Progression ◽

Molecular Mechanisms ◽

Cyclin D3 ◽

Luciferase Reporter

Abstract Background: Cyclin D3-CDK6 complex is a component of the core cell cycle machinery that regulates cell proliferation. By using Human Protein Atlas database, a higher expression level of this complex was found in gastric cancer. However, the function of this complex in gastric cancer remain poorly understood. This study aims to determine the expression pattern of this complex in gastric cancer and to investigate its biological role during tumorigenesis.Methods: To demonstrate that Cyclin D3-CDK6 regulate the c-Myc/miR-15a/16 axis in a feedback loop in gastric cancer, a series of methods were conducted both in vitro and in vivo experiments, including qRT-PCR, western blot analysis, EdU assay, ﬂow cytometry, luciferase reporter assay and immunohistochemical staining. SPSS and Graphpad prism software were used for data analysis.Results: In this study, we found that Cyclin D3 and CDK6 were significantly upregulated in gastric cancer and correlated with poorer overall survival. Further study proved that this complex significantly promoted cell proliferation and cell cycle progression in vitro and accelerated xenografted tumor growth in vivo. Furthermore, we explored the molecular mechanisms through which the complex mediated Rb phosphorylation and then promoted c-Myc expression in vitro, we also found c-Myc could suppress miR-15a/16 expression in gastric cancer cell. Finally, we found that miR-15a/16 can simultaneously regulate Cyclin D3 and CDK6 expression as direct target genes.Conclusions: Our findings uncover the Cyclin D3-CDK6/c-Myc/miR-15a/16 feedback loop axis as a pivotal role in the regulation of gastric cancer tumorigenesis, and this regulating axis may provide a potential therapeutic target for gastric cancer treatment.

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Supplemental N-3 Polyunsaturated Fatty Acids Limit A1-Specific Astrocyte Polarization via Attenuating Mitochondrial Dysfunction in Ischemic Stroke in Mice

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/5524705 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Jun Cao ◽

Lijun Dong ◽

Jialiang Luo ◽

Fanning Zeng ◽

Zexuan Hong ◽

...

Keyword(s):

Fatty Acids ◽

Ischemic Stroke ◽

Polyunsaturated Fatty Acids ◽

Mitochondrial Dysfunction ◽

Artery Occlusion ◽

Mice Model ◽

Neuron Death ◽

The Impact

Ischemic stroke is one of the leading causes of death and disability for adults, which lacks effective treatments. Dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs) exerts beneficial effects on ischemic stroke by attenuating neuron death and inflammation induced by microglial activation. However, the impact and mechanism of n-3 PUFAs on astrocyte function during stroke have not yet been well investigated. Our current study found that dietary n-3 PUFAs decreased the infarction volume and improved the neurofunction in the mice model of transient middle cerebral artery occlusion (tMCAO). Notably, n-3 PUFAs reduced the stroke-induced A1 astrocyte polarization both in vivo and in vitro. We have demonstrated that exogenous n-3 PUFAs attenuated mitochondrial oxidative stress and increased the mitophagy of astrocytes in the condition of hypoxia. Furthermore, we provided evidence that treatment with the mitochondrial-derived antioxidant, mito-TEMPO, abrogated the n-3 PUFA-mediated regulation of A1 astrocyte polarization upon hypoxia treatment. Together, this study highlighted that n-3 PUFAs prevent mitochondrial dysfunction, thereby limiting A1-specific astrocyte polarization and subsequently improving the neurological outcomes of mice with ischemic stroke.

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LINC00467 Promotes Tumor Progression via Regulation of the NF-kb Signal Axis in Bladder Cancer

Frontiers in Oncology ◽

10.3389/fonc.2021.652206 ◽

2021 ◽

Vol 11 ◽

Author(s):

Jiawei Xiao ◽

Lian Gong ◽

Mengqing Xiao ◽

Dong He ◽

Liang Xiang ◽

...

Keyword(s):

Bladder Cancer ◽

Signaling Pathway ◽

Molecular Mechanisms ◽

Animal Experiments ◽

Bioinformatic Analysis ◽

New Strategy ◽

Patient Prognosis

PurposeLong non-coding RNAs (lncRNAs) play an important role in the occurrence and development of bladder cancer, but the underlying molecular mechanisms remain largely unknown. In this study, we found that LINC00467 was significantly highly expressed in bladder cancer through bioinformatic analysis. The present study aimed to explore the role of LINC00467 in bladder cancer and its possible underlying molecular mechanisms.MethodsThe expression of LINC00467 was obtained from GEO (GSE31189), the TCGA database, and qRT-PCR. The role of LINC00467 in bladder cancer was assessed both in vitro and in vivo. RIP, RNA pulldown, and CO-IP were used to demonstrate the potential mechanism by which LINC00467 regulates the progression of bladder cancer.ResultsThrough the analysis of GEO (GSE133624) and the TCGA database, it was found that LINC00467 was highly expressed in bladder cancer tissues and that the expression of LINC00467 was significantly negatively correlated with patient prognosis. Cell and animal experiments suggest that LINC00467 promotes the proliferation and invasion of bladder cancer cells. On the one hand, LINC00467 can directly bind to NF-kb-p65 mRNA to stabilize its expression. On the other hand, LINC00467 can directly bind to NF-kb-p65 to promote its translocation into the nucleus to activate the NF-κB signaling pathway, which promotes the progression of bladder cancer.ConclusionsLINC00467 is highly expressed in bladder cancer and can promote the progression of bladder cancer by regulating the NF-κB signaling pathway. Therefore, targeting LINC00467 is very likely to provide a new strategy for the treatment of bladder cancer and for improving patient prognosis.

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