Arsenic trioxide induces macrophage autophagy and atheroprotection by regulating ROS-dependent TFEB nuclear translocation and AKT/mTOR pathway

AbstractInducing autophagy and inhibiting apoptosis may provide a therapeutic treatment for atherosclerosis (AS). For the treatment of progressive AS, arsenic trioxide (ATO) has been used to coat vascular stents. However, the effect of ATO on autophagy of macrophages is still unknown. Therefore, the aims of this study were to characterize the effects and the mechanism of actions of ATO on autophagy in macrophages. Our results showed that ATO-induced activation of autophagy was an earlier event than ATO-induced inhibition of the expression of apoptosis markers in macrophages and foam cells. Nuclear transcription factor EB (TFEB) prevents atherosclerosis by activating macrophage autophagy and promoting lysosomal biogenesis. Here, we report that ATO triggered the nuclear translocation of TFEB, which in turn promoted autophagy and autophagosome-lysosome fusion. Both the latter events were prevented by TFEB knockdown. Moreover, ATO decreased the p-AKT and p-mTOR in the PI3K/AKT/mTOR signaling pathway, thus inducing autophagy. Correspondingly, treatment with the autophagy inhibitor 3-methyladenine (3-MA) abolished the autophagy-inducing effects of ATO. Meanwhile, PI3K inhibitor (LY294002) and mTOR inhibitor (rapamycin) cooperated with ATO to induce autophagy. Furthermore, reactive oxygen species (ROS) were generated in macrophages after treatment with ATO. The ROS scavenger N-acetyl-1-cysteine (NAC) abolished ATO-induced nuclear translocation of TFEB, as well as changes in key molecules of the AKT/mTOR signaling pathway and downstream autophagy. More importantly, ATO promoted autophagy in the aorta of ApoE−/− mice and reduced atherosclerotic lesions in early AS, which were reversed by 3-MA treatment. In summary, our data indicated that ATO promoted ROS induction, which resulted in nuclear translocation of TFEB and inhibition of the PI3K/AKT/mTOR pathway. These actions ultimately promoted macrophage autophagy and reduced atherosclerotic lesions at early stages. These findings may provide a new perspective for the clinical treatment of early-stage atherosclerosis and should be further studied.

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Targeting mammalian target of rapamycin: prospects for the treatment of inflammatory bowel diseases

Current Medicinal Chemistry ◽

10.2174/0929867327666200504081503 ◽

2020 ◽

Vol 27 ◽

Author(s):

Naser-Aldin Lashgari ◽

Nazanin Momeni Roudsari ◽

Saeideh Momtaz ◽

Negar Ghanaatian ◽

Parichehr Kohansal ◽

...

Keyword(s):

Signaling Pathway ◽

Mammalian Target Of Rapamycin ◽

Mtor Pathway ◽

Mtor Signaling ◽

Target Of Rapamycin ◽

In Vivo Studies ◽

Cochrane Library ◽

Mtor Signaling Pathway ◽

Inflammatory Bowel

: Inflammatory bowel disease (IBD) is a general term for a group of chronic and progressive disorders. Several cellular and biomolecular pathways are implicated in the pathogenesis of IBD, yet the etiology is unclear. Activation of the mammalian target of rapamycin (mTOR) pathway in the intestinal epithelial cells was also shown to induce inflammation. This review focuses on the inhibition of the mTOR signaling pathway and its potential application in treating IBD. We also provide an overview on plant-derived compounds that are beneficial for the IBD management through modulation of the mTOR pathway. Data were extracted from clinical, in vitro and in vivo studies published in English between 1995 and May 2019, which were collected from PubMed, Google Scholar, Scopus and Cochrane library databases. Results of various studies implied that inhibition of the mTOR signaling pathway downregulates the inflammatory processes and cytokines involved in IBD. In this context, a number of natural products might reverse the pathological features of the disease. Furthermore, mTOR provides a novel drug target for IBD. Comprehensive clinical studies are required to confirm the efficacy of mTOR inhibitors in treating IBD.

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The polyphenol/saponin-rich Rhus tripartita extract has an apoptotic effect on THP-1 cells through the PI3K/AKT/mTOR signaling pathway

BMC Complementary Medicine and Therapies ◽

10.1186/s12906-021-03328-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Hajer Tlili ◽

Anca Macovei ◽

Daniela Buonocore ◽

Manuela Lanzafame ◽

Hanen Najjaa ◽

...

Keyword(s):

Signaling Pathway ◽

Plant Extract ◽

Therapeutic Potential ◽

Mtor Pathway ◽

Mtor Signaling ◽

Cellular Growth ◽

Cancer Drug ◽

Mtor Signaling Pathway ◽

Epicatechin Gallate ◽

Saponin Content

Abstract Background Hyperactivation of mechanistic target of rapamycin (mTOR) signaling pathway is involved in the regulation of cellular growth, proliferation, and more in general, is a common phenomenon in most types of cancers. Thus, natural substances targeting this pathway can be of great therapeutic potential in supporting the treatment of tumor patients. Rhus tripartita (Ucria) Grande is a plant growing in desertic areas which is traditionally used for the treatment of several diseases in Tunisia. In the present work, the biochemical profile of the main compounds present in the plant leaf extract was determined and the anti-leukemic potential of the plant extracts against acute monocytic leukaemia (AML) THP-1 cells was investigated. Methods After HPLC identification of some phenolic compounds present in the plant extract and the quantification of saponin content, the cytotoxic effect of Rhus tripartita extracts on THP-1 cell culture was evaluated using the colorimetric MTT assay for cell viability. THP-1 cells were incubated with medium containing the relative IC50 concentrations of total plant extract, saponin extract and some standard compounds (rutin (R); kaempferol (K); mixture of catechin, epicatechin, and epicatechin-gallate (CEEG); ellagic acid (EA). Finally, qRT-PCR and western blotting analysis were used to evaluate the effect of some flavonoids present in a crude extract of polyphenols and the total extract of saponins on cell survival and apoptosis. Results Analysis of expression level of some gene (PIK3CA, PTEN, AKT1, mTOR, EIF4E, RPS6KB1, and TSC1) involved in the mTOR pathway and the phosphorylation of S6 and AKT proteins allowed to observe that a total Rhus tripartita extract and some of the compounds found in the extract controls THP-1 cell proliferation and apoptosis via regulation of the PI3K-Akt-mTOR signaling pathway. Conclusion Rhus tripartita-induced inhibition of cell cycle and induction of apoptosis may involve the mTOR pathway. Therefore, Rhus tripartita extract may be a useful candidate as a natural anti-cancer drug to support the treatment of AML.

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Zisheng Shenqi Decoction Ameliorates Monosodium Urate-Mediated Gouty Arthritis in Rats via Promotion of Autophagy through the AMPK/mTOR Signaling Pathway

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2021/6918026 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Jieru Han ◽

Guangyu Shi ◽

Wenhao Li ◽

Shuhui Wang ◽

Jixiang Bai ◽

...

Keyword(s):

Signaling Pathway ◽

Nuclear Translocation ◽

Gouty Arthritis ◽

Nitrogen Monoxide ◽

Joint Space ◽

Mtor Signaling ◽

Receptor Protein ◽

Related Factor ◽

Monosodium Urate ◽

Mtor Signaling Pathway

Gouty arthritis (GA) is an inflammatory disease owing to the accumulation of monosodium urate (MSU) in joints, leading to redness and burning pain. In this study, the effect of Zisheng Shenqi Decoction (ZSD) on a rat model of MSU-induced GA was investigated. ZSD obviously diminished the right paw thickness, the degree of the swelling of the paw, and the infiltration of the inflammatory cell, as well as cartilage erosion, and widened the joint space in MSU-treated rats. Besides, MSU remarkably elevated the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-18; however, ZSD treatment dose dependently lowered these levels and resulted in a significant decrease in articular elastase activity. Also, ZSD administration increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) but declined malondialdehyde (MDA) and nitrogen monoxide (NO) contents. Importantly, western blotting analysis revealed that NOD-like receptor protein 3 (NLRP3), cleaved caspase-1, IL-1β, nuclear factor-E2-related factor 2 (Nrf2) in the cytoplasm, phosphorylated mammalian target of rapamyclin (p-mTOR), and p62 expressions were downregulated, whereas the levels of nuclear Nrf2, phosphorylated AMP-activated protein kinase (p-AMPK), Beclin-1, and LC3II/I were upregulated by ZSD. Immunofluorescence assay indicated that ZSD evidently promoted nuclear translocation of LC3. Taken together, ZSD inhibited inflammation and oxidative stress and facilitated autophagy through the activation of the AMPK pathway and suppression of the mTOR signaling pathway, demonstrating its potential for preventing and curing GA.

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The Combination Treatment of Curcumin and Probucol Protects Chondrocytes from TNF-α Induced Inflammation by Enhancing Autophagy and Reducing Apoptosis via the PI3K-Akt-mTOR Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/5558066 ◽

2021 ◽

Vol 2021 ◽

pp. 1-20

Author(s):

Guangtao Han ◽

Yubiao Zhang ◽

Haohuan Li

Keyword(s):

Signaling Pathway ◽

Combination Treatment ◽

Inflammatory Cytokine ◽

Combined Treatment ◽

Mtor Pathway ◽

Mtor Signaling ◽

Mtor Signaling Pathway ◽

Tnf Α

Osteoarthritis (OA) is a chronic joint disease characterized by cholesterol accumulation in chondrocytes, cartilage degeneration, as well as extracellular matrix (ECM) destruction, and joint dysfunction. Curcumin, a chemical that can reduce cholesterol levels in OA patients, also can inhibit the progression of OA. However, a high concentration of curcumin may also trigger apoptosis in normal chondrocytes. Besides curcumin, probucol that is found can also effectively decrease the cholesterol level in OA patients. Considering that high cholesterol is a risk factor of OA, it is speculated that the combination treatment of curcumin and probucol may be effective in the prevention of OA. To investigate the possible effects of such two chemicals on OA pathophysiology, chondrocyte apoptosis and autophagy behavior under inflammatory cytokine stress were studied, and specifically, the PI3K-Akt-mTOR signaling pathway was studied. Methods. Cell proliferation, colony formation, and EdU assay were performed to identify the cytotoxicity of curcumin and probucol on chondrocytes. Transwell assay was conducted to evaluate chondrocyte migration under TNF-α inflammation stress. Immunofluorescence, JC-1, flow cytometry, RT-PCR, and western blot were used to investigate the signal variations related to autophagy and apoptosis in chondrocytes and cartilage. A histological study was carried out on OA cartilage. Glycosaminoglycan (GAG) release was determined to evaluate the ECM degradation under stress. Results. Compared with a single intervention with curcumin or probucol, a combined treatment of these two chemicals is more effective in terms of protecting chondrocytes from stress injury induced by inflammatory cytokines. The promoted protection may be attributed to the inhibition of apoptosis and the blockage of the autophagy-related PI3K/Akt/mTOR pathway. Such results were also verified in vitro by immunofluorescence staining of OA chondrocytes and in vivo by immunohistochemistry staining of cartilage. Besides, in vivo studies also showed that when applied in combination, curcumin and probucol could block the PI3K-AKT-mTOR signaling pathway; promote COL-II expression; suppress P62, MMP-3, and MMP-13 expression; and inhibit TNF-α-stimulated cartilage degradation. Moreover, the combined medication could help reduce the release of ECM GAGs in OA cartilage and alleviate the severity of OA. Conclusion. A combined treatment of curcumin and probucol could be used to protect chondrocytes from inflammatory cytokine stress via inhibition of the autophagy-related PI3K/Akt/mTOR pathway both in vitro and in vivo, which might be of potential pharmaceutical value for OA prevention and therapy.

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Beneficial Effects of Resveratrol-Mediated Inhibition of the mTOR Pathway in Spinal Cord Injury

Neural Plasticity ◽

10.1155/2018/7513748 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 5

Author(s):

Jingying Zhou ◽

Xue Huo ◽

Benson O. A. Botchway ◽

Luyao Xu ◽

Xiaofang Meng ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Signaling Pathway ◽

Mammalian Target Of Rapamycin ◽

Mtor Pathway ◽

Mtor Signaling ◽

High Rate ◽

Mtor Signaling Pathway ◽

Beneficial Effects ◽

Cord Injury

Spinal cord injury (SCI) causes a high rate of morbidity and disability. The clinical features of SCI are divided into acute, subacute, and chronic phases according to its pathophysiological events. The mammalian target of rapamycin (mTOR) signaling pathway plays an important role in cell death and inflammation in the acute phase and neuroregeneration in the subacute/chronic phases at different times. Resveratrol has the potential of regulating cell growth, proliferation, metabolism, and angiogenesis through the mTOR signaling pathway. Herein, we explicate the role of resveratrol in the repair of SCI through the inhibition of the mTOR signaling pathway. The inhibition of the mTOR pathway by resveratrol has the potential of serving as a neuronal restorative mechanism following SCI.

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The polyphenol/saponin-rich Rhus tripartita extract has an apoptotic effect on THP-1 cells through the PI3K/AKT/mTOR signaling pathway

10.21203/rs.3.rs-138978/v1 ◽

2021 ◽

Author(s):

Hajer Tlili ◽

Anca Macovei ◽

Daniela Buonocore ◽

Manuela Lanzafame ◽

Hanen Najjaa ◽

...

Keyword(s):

Signaling Pathway ◽

Plant Extract ◽

Therapeutic Potential ◽

Mtor Pathway ◽

Mtor Signaling ◽

Cellular Growth ◽

Cancer Drug ◽

Mtor Signaling Pathway ◽

Epicatechin Gallate ◽

Saponin Content

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Glucose-induced lipid deposition in goose primary hepatocytes is dependent on the PI3K-Akt-mTOR signaling pathway

Archives of Biological Sciences ◽

10.2298/abs151210075h ◽

2016 ◽

Vol 68 (4) ◽

pp. 853-861

Author(s):

Chunchun Han ◽

Shouhai We ◽

Fang He ◽

Song Qi ◽

Xiangping Xiong ◽

...

Keyword(s):

Fatty Acid ◽

Lipid Metabolism ◽

Signaling Pathway ◽

Fatty Acid Oxidation ◽

Mtor Pathway ◽

Mtor Signaling ◽

Acid Oxidation ◽

Lipid Deposition ◽

Mtor Signaling Pathway ◽

Primary Hepatocytes

Previously we showed that fatty liver formation in overfed geese was accompanied by PI3K-Akt-mTOR pathway activation and changes in plasma glucose concentrations. Here, we show that glucose acts in goose hepatocellular lipid metabolism through the PI3K-Akt-mTOR signaling pathway. We observed that glucose increased lipogenesis, decreased fatty acid oxidation and increased very low density lipoprotein triglyceride (VLDL-TG) assembly and secretion. Co-treatment with glucose and inhibitors of the PI3K-Akt-mTOR pathway (LY294002, rapamycin, NVP-BEZ235) decreased the levels of factors involved in lipogenesis and increased the levels of factors involved in fatty acid oxidation and VLDL-TG assembly and secretion. These findings show that inhibition of the PI3K-Akt-mTOR pathway decreased glucose-induced lipogenesis, inhibited the downregulation of fatty acid oxidation by glucose and increased the upregulation of VLDL-TG assembly and secretion by glucose. The results presented herein provide further support for the role of the PI3K-Akt-mTOR pathway in lipid metabolism as we showed that in goose primary hepatocytes, glucose acts through the PI3K-Akt-mTOR-dependent pathway to stimulate lipid deposition by increasing lipogenesis and decreasing fatty acid oxidation and VLDL-TG assembly and secretion.

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Mammalian Target of Rapamycin Is Activated in Association with Myometrial Proliferation during Pregnancy

Endocrinology ◽

10.1210/en.2009-0419 ◽

2009 ◽

Vol 150 (10) ◽

pp. 4672-4680 ◽

Cited By ~ 41

Author(s):

Shabana Jaffer ◽

Oksana Shynlova ◽

Stephen Lye

Keyword(s):

Insulin Receptor ◽

Signaling Pathway ◽

Mammalian Target Of Rapamycin ◽

Mtor Pathway ◽

Mtor Signaling ◽

Target Of Rapamycin ◽

Insulin Receptor Substrate ◽

Mtor Signaling Pathway ◽

Insulin Receptor Substrate 1 ◽

Ovx Rats

Abstract The adaptive growth of the uterus during gestation involves gradual changes in cellular phenotypes from the early proliferative to the intermediate synthetic phase of cellular hypertrophy, ending in the final contractile/labour phenotype. The mammalian target of rapamycin (mTOR) signaling pathway regulates cell growth and proliferation in many tissues. We hypothesized that mTOR was a mediator of hormone-initiated myometrial hyperplasia during gestation. The protein expression and phosphorylation levels of mTOR, its upstream regulators [insulin receptor substrate-1, phosphoinositide-3-kinase (PI3K), Akt], and downstream effectors [S6-kinase-1 (S6K1) and eI4FE-binding protein 1 (4EBP1)] were analyzed throughout normal pregnancy in rats. In addition, we used an ovariectomized (OVX) rat model to analyze the modulation of the mTOR pathway and proliferative activity of the uterine myocytes by estradiol alone and in combination with the mTOR-specific inhibitor rapamycin. Our results demonstrate that insulin receptor substrate-1 protein levels and the phosphorylated (activated) forms of PI3K, mTOR, and S6K1 were significantly up-regulated in the rat myometrium during the proliferative phase of pregnancy. Treatment of the OVX rats with estradiol caused a transient increase in IGF-I followed by an up-regulation of the PI3K/mTOR pathway, which became apparent by a cascade of phosphorylation reactions (P-P85, P-Akt, P-mTOR, P-S6K1, and P-4EBP1). Rapamycin blocked activation of P-mTOR, P-S6K1, and P-4EBP1 proteins and significantly reduced the number of proliferating cells in the myometrium of OVX rats. Our in vivo data demonstrate that estradiol was able to activate the PI3K/mTOR signaling pathway in uterine myocytes and suggest that this activation is responsible for the induction of myometrial hyperplasia during early gestation.

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MLN4924, An Investigational NAE Inhibitor, Suppresses AKT and mTOR Signaling Pathway Through up Regulating REDD1 in Human Myeloma Cells

Blood ◽

10.1182/blood.v118.21.1870.1870 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1870-1870

Author(s):

Yanyan Gu ◽

Jonathan L. Kaufman ◽

Lawrence H. Boise ◽

Sagar Lonial

Keyword(s):

Multiple Myeloma ◽

Western Blot ◽

Signaling Pathway ◽

Cell Lines ◽

Research Funding ◽

Myeloma Cell ◽

Mtor Pathway ◽

Mtor Signaling ◽

Mtor Signaling Pathway ◽

Myeloma Cells

Abstract Abstract 1870 Introduction: The development and survival of normal plasma cells as well as multiple myeloma cells depend on an elaborately regulated ubiquitin proteasome system (UPS). Proteasome inhibitors such as bortezomib have proved to be highly active in the treatment of multiple myeloma. MLN4924, a newly developed investigational NEDD8 activating enzyme (NAE) inhibitor, exhibits promising anti-tumor effect through both clinical and laboratory observation. We sought to evaluate the individual signaling effects of MLN4924 in multiple myeloma, with the intent of further understanding the mechanism of action and identifying potential combinations. Methods: Human myeloma cell lines (MM.1S, MM.1R and U266) were treated with increasing concentrations of MLN4924 for 24, 48 and 72 hrs respectively or concurrently with bortezomib. Cell viability (MTT), apoptosis, western blot, RT-qPCR and siRNA assays were used to identify the cellular and molecular sequelae of MLN4924 treatment. Results: Single agent studies demonstrate that MLN4924 induces cytotoxicity in all three MM cell lines. Cytotoxicity is associated with increased apoptosis and suppression of AKT and mTOR signaling pathway, as detected by FACS and western blot. MLN4924 suppresses protein turnover of Cullin-ring ligases substrates leading to stabilization of specific proteins, such as p27, CDT1, NRF2. We find that REDD1, a substrate of CUL4 A–DDB 1–ROC1–β-TRCP ubiquitin ligase and negative regulator of mTOR pathway, increases in as early as 2 hours when treated with MLN4924. Knock-down of REDD1 using siRNA alleviates MLN4924 induced AKT, mTOR signaling suppression as well as the growth inhibition, which suggests that MLN4924 inhibits AKT, mTOR signaling through upregulating REDD1 protein leading to cytotoxicity. Combining MLN4924 with bortezomib synergistically enhances the antitumor effect of MLN4924. Western blot confirms the development of significantly increased procaspase and PARP cleavage, as well as substantial down regulation of AKT and mTOR signaling. Neither IL-6 nor IGF-1 is able to abrogate these combination effects. When we silence REDD1 in the combination assay in MM.1R, we find less cell apoptosis and suppression of AKT, mTOR pathway, which further support that REDD1 is an important regulator for MLN4924 induced cytotoxicity in MMs. Conclusion: MLN4924 is a potent investigational antitumor compound suppressing mTOR signaling pathways in myeloma cell lines. Down-regulation of the mTOR signaling pathway is associated with increased expression of REDD1. Combination of MLN4924 with the proteasome inhibitor bortezomib induces synergistic apoptosis in MMs cell lines which can overcome the prosurvival effects of growth factor (IL-6 and IGF-1). These findings could positively impact clinical combination strategies. Disclosures: Kaufman: Millenium: Consultancy; Onyx Pharmaceuticals: Consultancy; Novartis: Consultancy; Keryx: Consultancy; Merck: Research Funding; Celgene: Research Funding. Lonial:Millennium Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; Onyx: Consultancy; Merck: Consultancy.

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Hypoxia-Induced Glioma-Derived Exosomal miRNA-199a-3p Promotes Ischemic Injury of Peritumoral Neurons by Inhibiting the mTOR Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/5609637 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Jian-Lan Zhao ◽

Bo Tan ◽

Gong Chen ◽

Xiao-Ming Che ◽

Zhuo-Ying Du ◽

...

Keyword(s):

Signaling Pathway ◽

Molecular Mechanisms ◽

Glioma Cells ◽

Ischemic Injury ◽

Neuronal Injury ◽

Mtor Pathway ◽

Mtor Signaling ◽

C6 Glioma Cells ◽

Mtor Signaling Pathway ◽

Exosomal Mirna

The underlying molecular mechanisms that the hypoxic microenvironment could aggravate neuronal injury are still not clear. In this study, we hypothesized that the exosomes, exosomal miRNAs, and the mTOR signaling pathway might be involved in hypoxic peritumoral neuronal injury in glioma. Multimodal radiological images, HE, and HIF-1α staining of high-grade glioma (HGG) samples revealed that the peritumoral hypoxic area overlapped with the cytotoxic edema region and directly contacted with normal neurons. In either direct or indirect coculture system, hypoxia could promote normal mouse hippocampal neuronal cell (HT22) injury, and the growth of HT22 cells was suppressed by C6 glioma cells under hypoxic condition. For administrating hypoxia-induced glioma-derived exosomes (HIGDE) that could aggravate oxygen-glucose deprivation (OGD)/reperfusion neuronal injury, we identified that exosomes may be the communication medium between glioma cells and peritumoral neurons, and we furtherly found that exosomal miR-199a-3p mediated the OGD/reperfusion neuronal injury process by suppressing the mTOR signaling pathway. Moreover, the upregulation of miRNA-199a-3p in exosomes from glioma cells was induced by hypoxia-related HIF-1α activation. To sum up, hypoxia-induced glioma-derived exosomal miRNA-199a-3p can be upregulated by the activation of HIF-1α and is able to increase the ischemic injury of peritumoral neurons by inhibiting the mTOR pathway.

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