Inhibition Of mTOR Signaling Pathway Research Articles

D-Glucosamine induces circadian phase delay by promoting BMAL1 degradation through AMPK/mTOR pathway

Circadian rhythms are closely linked to the metabolic network through circadian feedback regulation. The hexosamine biosynthetic pathway (HBP) is a branch of glucose metabolism that affects circadian rhythms through the O-linked N-acetylglucosamine modification (O-GlcNAcylation) of clock proteins. Here, we found out that, among the downstream metabolites regulated by d-glucosamine (GlcN) in HBP salvage pathway, only GlcN is able to induce circadian phase delay both in vitro and in vivo. Mechanistic studies indicated that the phase-shift induced by GlcN is independent of O-GlcNAcylation. Instead, GlcN selectively up-regulates p-AMPK activity, leading to the inhibition of mTOR signaling pathway, and thus down-regulation of p-BMAL1 both in human cell line and mouse tissues. Moreover, GlcN promoted BMAL1 degradation via proteasome pathway. These findings reveal a novel molecular mechanism of GlcN in regulating clock phase and suggest the therapeutic potential of GlcN as new use for an old drug in the future treatment of shift work and circadian misalignment.

Targeting lncRNA DDIT4-AS1 Sensitizes Triple Negative Breast Cancer to Chemotherapy via Suppressing of Autophagy.

In this study, it is found that the lncRNA, DNA damage inducible transcript 4 antisense RNA1 (DDIT4-AS1), is highly expressed in triple-negative breast cancer (TNBC) cell lines and tissues due to H3K27 acetylation in the promoter region, and promotes the proliferation, migration, and invasion of TNBC cells via activating autophagy. Mechanistically, it is shown that DDIT4-AS1 induces autophagy by stabilizing DDIT4 mRNA via recruiting the RNA binding protein AUF1 and promoting the interaction between DDIT4 mRNA and AUF1, thereby inhibiting mTOR signaling pathway. Furthermore, silencing of DDIT4-AS1 enhances the sensitivity of TNBC cells to chemotherapeutic agents such as paclitaxel both in vitro and in vivo. Using a self-activatable siRNA/drug core-shell nanoparticle system, which effectively deliver both DDIT4-AS1 siRNA and paclitaxel to the tumor-bearing mice, a significantly enhanced antitumor activity is achieved. Importantly, the codelivery nanoparticles exert a stronger antitumor effect on breast cancer patient-derived organoids. These findings indicate that lncRNA DDIT4-AS1-mediated activation of autophagy promotes progression and chemoresistance of TNBC, and targeting of DDIT4-AS1 may be exploited as a new therapeutic approach to enhancing the efficacy of chemotherapy against TNBC.

The therapeutic prospect of zinc oxide nanoparticles in experimentally induced diabetic nephropathy

ABSTRACT Diabetic nephropathy (DN) is the most frequent cause of end-stage renal failure. Zinc oxide nanoparticles (ZnO-NPs) are promising antidiabetic agents. Our aim was to evaluate the prospective efficacy of ZnO-NPs in treating DN in streptozotocin-induced diabetic rats. Rats were randomly dispersed into three sets: control group, DN group and DN + ZnO-NPs group. ZnO-NPs were given at a dose of 10 mg/kg/day by oral gavage for 4 weeks. Urine and blood samples were processed for biochemical analyses. Kidney samples were managed for light and electron microscopy studies. Immune histochemical staining of P53, aquaporin11 (AQP11) and mechanistic target of rapamycin (mTOR) were performed. Gene analyses of nephrin, podocin, beclin-1, LC3 and p62 were done. Administration of ZnO-NPs ameliorated the functional and histopathological alterations of the kidney in a rat model of diabetic nephropathy. ZnO-NPs retained the constancy of the glomerular filtration barrier and restored almost normal renal structure. This was confirmed by upregulation of mRNA expression of podocyte markers (nephrin and podocin) and AQP11 immune histochemical expression in the renal tubules. The beneficial outcomes of ZnO-NPs might be attributed to activation of autophagy through inhibiting mTOR signaling pathway. ZnO-NPs enhanced beclin-1 and LC3 mRNA expressions and reduced p62 mRNA expression. ZnO-NPs also exerted anti-apoptotic potential (evidenced by the decrease in p53 immune expression), anti-inflammatory and anti-oxidant effect [endorsed by suppression of serum cyclooxygenase-2 (COX-2) enzyme activity, tissue nuclear factor kappa beta (NF-κB) level and blood hypoxia-inducible factors (HIF-1α) level]. These results may point the way to an effective therapy of DN. Abbreviations: AQP11 Aquaporin11; BUN: Blood urea nitrogen; COX-2: Cyclooxygenase-2; DAB: 3, 3’-diaminobenzidine; DM: Diabetes mellitus; DN: Diabetic nephropathy; ELISA: Enzyme-linked immunosorbent assay; H&E: Hematoxylin & eosin; HIF-1α: Hypoxia-inducible factors; iNOS: inducible nitric oxide synthase; LC3: Microtubule-associated protein 1 light chain 3; mTOR: Mechanistic target of rapamycin; NF-κB: Nuclear factor kappa beta; NPs: Nanoparticles; PAS: Periodic acid Schiff; PCR: Polymerase chain reaction; PGE2: Prostaglandin E2; ROS: Reactive oxygen species; STZ: Streptozotocin; X ± SEM: Mean ± standard error of means; Zn: Zinc; ZnO-NPs: Zinc oxide nanoparticles.

Enhanced Activation of mTOR Signaling Pathway Was Found in the Hypertrophic and Nodular Lesions of Port Wine Stains.

BackgroundPort wine stain (PWS) is a congenital skin lesion involving capillary malformations. Most PWS lesions will gradually become hypertrophic and appear nodular in contour. Current research shows that rapamycin, an mTOR inhibitor, is probably a promising adjunctive therapy for PWS, which suggests that the mTOR signaling pathway may play an important role in its pathological process.MethodsFrom January 2013 to January 2019, 13 samples were obtained during the surgical excision. Each sample was divided into 3 parts according to the type of lesion, namely, the flat, hypertrophic and nodular lesions. Pathologic structures of each type were observed under the microscope after HE staining. The expression of mTORC1, p70S6, p-p70S6, eIF4EBP1 and p-eIF4EBP1 was examined by immunohistochemical staining and western blotting. The location of the expression of mTORC1, p-p70S6 and p-elF4EBP1 was further detected by immunofluorescence staining.ResultsLarge amounts of dilated and malformed vessels were observed in all types of PWS lesions. Abundant hyperplastic hair follicles/glands were shown in the hypertrophic or nodular lesions. Phosphorylation level of p70S6 and elF4EBP1 in PWS was significantly higher than those in normal skin and increased accordingly in the progression of PWS. Activated molecules in mTOR signaling pathway were mostly located in the endothelium of malformed vessels. They were also located in the hyperplastic hair follicles/glands of hypertrophic and nodular lesions.ConclusionThe mTOR signaling pathway was increasingly activated during the progression of PWS. Enhanced activation of mTOR signaling pathway may contribute to the hypertrophy and nodularity of PWS. The results provide preliminary evidence for treating PWS and related syndromes by inhibiting mTOR signaling pathway.

Isorhamnetin alleviates lipopolysaccharide-induced acute lung injury by inhibiting mTOR signaling pathway

Aim: Acute Lung Injury (ALI) is an acute hypoxic respiratory insufficiency caused by various traumatic factors, manifested as progressive hypoxemia and respiratory distress, and lung imaging shows a heterogeneous osmotic outbreak. Isorhamnetin (ISO) is a flavonoid compound isolated and purified from medicinal plants, such as Hippophae rhamnoides L. and Ginkgo, and has multiple pharmacological functions, such as anti-tumor, anti-myocardial hypoxia, and cardiovascular protection. Our previous study has shown that ISO could attenuate lipopolysaccharide (LPS)-induced acute lung injury in mice, but its mechanism is not clear. Methods: In this study, we used LPS-induced mouse and cell models to research the mechanism of ISO alleviating acute lung injury. Results: The results showed that ISO could attenuate the injury of type II alveolar epithelial cells by inhibiting the TLR4/NF-κB pathway. Further studies showed that ISO could inhibit the activation of mTOR signal in vivo and in vitro and promote autophagy in alveolar epithelial cells to reduce lung injury caused by LPS. In addition, ISO could inhibit LPS-induced epithelial cell apoptosis. Conclusion: Overall, ISO could suppress injury and apoptosis of epithelial cells and activate autophagy to protect epithelial cells via inhibiting mTOR signal and attenuating LPS-induced acute lung injury in mice.

Mammalian Target of Rapamycin Inhibitor Rapamycin Alleviates 7-Ketocholesterol Induced Inflammatory Responses and Vascular Endothelial Growth Factor Elevation by Regulating MAPK Pathway in Human Retinal Pigment Epithelium Cells.

Purpose: To validate the protective effect of a mammalian target of rapamycin (mTOR) inhibitor on human retinal pigment epithelium (RPE) cells challenged with 7-ketocholesterol (7-KC) and explored the underlying mechanisms. Methods: Human primary RPE (hRPE) cells and ARPE-19 cells were cultured with or without 10 nM of rapamycin for 6 h before being exposed to 10 μM of 7-KC for 24 h. The transcriptome of 7-KC challenged ARPE-19 cells was investigated by RNA sequencing (RNA-seq). The effects of 7-KC and rapamycin on the viability of ARPE-19 cells were measured with CCK-8. Gene expression was verified by real-time PCR, and protein levels were determined by ELISA or Western blotting. Results: The expression of IL-6, IL-8, and vascular endothelial growth factor (VEGF) in RPE cells was markedly increased after stimulation with 7-KC for 12/24 h compared with the controls. RNA-seq showed that a total of 10,243 genes were differentially expressed, with 5,518 genes upregulated and 4,725 genes downregulated between the 7-KC treated and the control group. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that 7-KC stimulation activated mTOR signaling and other pathways, including adherent junction, MAPK, and Wnt signalings. mTOR inhibitor rapamycin significantly suppressed the elevation of IL-6, IL-8, and VEGF stimulated by 7-KC. Rapamycin not only decreased the level of phosphorylated mTOR, P70S6K, 4EBP1 but also inhibited the activation of MAPK pathway. Conclusions: Inhibition of mTOR signaling pathway suppressed the elevation of inflammatory cytokines IL-6, IL-8, and the angiogenic agent VEGF induced by 7-KC. The protective effect of rapamycin was associated with its downregulation on MAPK pathway.

Theobromine ameliorates nonalcoholic fatty liver disease by regulating hepatic lipid metabolism via mTOR signaling pathway in vivo and in vitro.

Theobromine, a methylxanthine present in cocoa, has been shown to possess many beneficial pharmacological properties such as anti-oxidative stress, anti-inflammatory property, and anti-microbial activity. In this study, we investigated the effects of theobromine on nonalcoholic fatty liver disease (NAFLD) and the possible underlying mechanisms in vivo and in vitro. The results showed that theobromine reduced body weight and fat mass and improved dyslipidemia. Theobromine mitigated liver injury and significantly reduced hepatic triglyceride level in mice with obesity. Histological examinations also showed hepatic steatosis was alleviated after theobromine treatment. Furthermore, theobromine reversed the elevated mRNA and protein expression of SREBP-1c, FASN, CD36, FABP4, and the suppressed expression of PPARα and CPT1a in the liver of mice with obesity, which were responsible for lipogenesis, fatty acid uptake, and fatty acid oxidation respectively. In vitro, theobromine also downregulated SREBP-1c, FASN, CD36, FABP4 and upregulated PPARα and CPT1a mRNA and protein levels in hepatocytes in a dose-dependent manner, while these changes were reversed by L-leucine, a mammalian target of rapamycin (mTOR) agonist. The present study demonstrated that theobromine improved NAFLD by inhibiting lipogenesis and fatty acid uptake and promoting fatty acid oxidation in the liver and hepatocytes, which might be associated with its suppression of mTOR signaling pathway. Novelty: Theobromine protects against high-fat diet - induced NAFLD. Theobromine inhibits lipogenesis and fatty acid uptake and promotes fatty acid oxidation in the liver and hepatocytes via inhibiting mTOR signaling pathway.

Wnt-3a improves functional recovery through autophagy activation via inhibiting the mTOR signaling pathway after spinal cord injury

Little is known about the effect of wnt-3a on motor nerve function and its specific molecular mechanisms after spinal cord injury (SCI). This study demonstrates that the downregulated expression levels of caspases-3, caspases-9 and chondroitin sulfate proteoglycan (CSPG) proteins and number of proportion of transferase UTP nick end labeling (TUNEL)-positive neurons by wnt-3a treatment. Then, Nissl and hematoxylin-eosin (HE) staining showed that wnt-3a significantly reduced the loss of spinal anterior horn motor neurons and promoted repair of injured spinal cord tissues after SCI. The above factors constructed a favorable microenvironment for the recovery of motor nerve function after SCI. To elucidate the molecular mechanism of neuroprotection of wnt-3a on SCI, the study showed that the expression levels of Beclin-1 and light chain (LC)3-II/I in spinal cord neurons were significantly improved by wnt-3a after SCI in vitro and vivo experiments, while the effect of wnt-3a was inhibited after mechanistic target of rapamycin (mTOR) signaling pathway being activated by MHY-1485. Besides, the level of p70S6K phosphorylation was inhibited by wnt-3a treatment, on the contrary, the level of p70S6K protein was elevated by wnt-3a, indicating that wnt-3a significantly activated neuronal autophagy by inhibiting mTOR signaling pathway after SCI. To further verify the correlation between neuroprotection of wnt-3a and autophagy, we found that after the rats and spinal cord neurons were combined treatment with wnt-3a and MHY-1485, the neuroprotection of wnt-3a on SCI was significantly inhibited. This study is the first to report that wnt-3a improves functional recovery through autophagy activation via inhibiting the mTOR signaling pathway after SCI.

Altered expression of activator proteins that control follicle reserve after ovarian tissue cryopreservation/transplantation and primordial follicle loss prevention by rapamycin.

We investigated whether expression of activator proteins that control follicle reserve and growth change after ovarian tissue vitrification and re-transplantation. Moreover, we assessed whether inhibition of mTOR signaling pathway by rapamycin would protect primordial follicle reserve after ovarian tissue freezing/thawing and re-transplantation. Fresh control, frozen/thawed, fresh-transplanted, frozen/thawed and transplanted, rapamycin/control, rapamycin fresh-transplanted, and rapamycin frozen-thawed and transplanted groups were established in rats. After freezing and thawing process, two ovaries were transplanted into the back muscle of the same rat. After 2weeks, grafts were harvested, fixed, and embedded into paraffin block. Normal and atretic primordial/growing follicle count was performed in all groups. Ovarian tissues were evaluated for the dynamic expressions of Gdf-9, Bmp-15, KitL, Lif, Fgf-2, and p-s6K using immunohistochemistry, and H-score analyses were done. Primordial follicle reserve reduced almost 50% after ovarian tissue re-transplantation. Expression of Gdf-9 and Lif increased significantly in primordial and growing follicles in frozen-thawed, fresh-transplanted, and frozen/thawed and transplanted groups, whereas expression of Bmp-15, KitL, and Fgf-2 decreased in primordial follicles. Freezing and thawing of ovarian tissue solely significantly increased p-s6K expression in primordial follicles, and on the other hand, suppression of mTORC1 pathway using rapamycin preserved the primordial follicle pool. Altered expressions of activator proteins that regulate primordial follicle reserve and growth may lead to primordial follicle loss and rapamycin treatment can protect ovarian reserve after ovarian tissue cryopreservation/transplantation.

MiR-101-3p sensitizes non-small cell lung cancer cells to irradiation

Recent studies have revealed that microRNAs regulate radiosensitivity of non-small cell lung cancer (NSCLC). The aim of this study was to investigate whether miR-101-3p is correlated with radiosensitivity of NSCLC. According to our results, miR-101-3p was downregulated in NSCLC tissues and cell lines. Moreover, miR-101-3p was decreased in A549 cells’ response to irradiation in a dose-dependent manner. Upregulation of miR-101-3p decreased survival fraction and colony formation rate and increased irradiation-induced apoptosis in irradiation-resistant cells, while miR-101-3p depletion had the opposite effects in irradiation-sensitive cells. Furthermore, mechanistic target of rapamycin (mTOR) is a target gene of miR-101-3p. The expressions of mTOR, p-mTOR, and p-S6 were curbed by overexpression of miR-101-3p in A549R cells, which was enhanced by repression of miR-101-3p in A549 cells. Intriguingly, elevation in mTOR abated miR-101-3p upregulation-induced increase in irradiation sensitivity in irradiation-resistant cell line. In contrast, rapamycin undermined miR-101-3p inhibitor-mediated reduction of irradiation sensitivity in irradiation-sensitive cell line. Besides, miR-101-3p overexpression enhanced the efficacy of radiation in an NSCLC xenograft mouse model. In conclusion, miR-101-3p sensitized A549 cells to irradiation via inhibition of mTOR-signaling pathway.

Anti-epileptic effect of 16-O-acetyldigitoxigenin via suppressing mTOR signaling pathway

Epilepsy is a common chronic disease of the central nervous system that can last for years or even decades, causing serious adverse effects on the body, mind, and psychology of patients. Traditional antiepileptic drugs can effectively control seizures, but because of large individual differences, serious adverse reactions, narrow therapeutic window and other shortcomings, more effective, new treatment drugs are looked for. Streptocaulon griffithii is a plant of Asclepiadaceae. 16-O-acetyldigitoxigenin (ACE) is a strong cardiac glycoside isolated from methanol extract of Streptocaulon griffithii. The aim of this study was to investigate the antiepileptic effect of ACE on Pilocarpine (Pilo) induced epilepsy in mice, and to explore the effect of mTOR signaling pathway on its antiepileptic effect. The results showed that ACE had antiepileptic and neuroprotective effects on Pilo induced epilepsy mice. ACE attenuates Pilo induced seizures by inhibiting the activation of p-mTOR/p-70S6K pathway, and inhibits Pilocarpine induced brain damage by inhibiting mTOR signaling pathway. These results suggest that ACE has a promising future in the treatment of epilepsy and other nervous system diseases.

Triptonide acts as a novel antiprostate cancer agent mainly through inhibition of mTOR signaling pathway.

The increasing incidence of prostate cancer (PCa) indicates an urgent need for the development of new effective drugs in PCa therapy. Triptonide has been reported to have a strong inhibition activity in cancers through screening of Chinese herbal medicine. This study aims to investigate the effects of triptonide on anti-PCa activity and its mechanisms. Three human advanced PCa cell lines PC3, DU145, and LNCap, and a human normal prostate epithelial cell line RWPE were treated with a range (0, 1.25, 2.5, 5, 10, 20, 40, 80, 160, and 320 nM) of triptonide concentrations for 72 hours respectively. Then, cell viability was assessed by cell counting kit-8. PCa cells were treated with different doses (0-20 nM) of triptonide for 72 hours. Cell cycle and apoptosis were assessed by flow cytometry assays. Nude mice bearing human PCa xenografts were intraperitoneally injected daily with either triptonide (10 mg/kg/d) or phosphate-buffered saline as a control for 35 days. RNA-sequencing (RNA-seq) was performed by an Illumina Hiseq Sequencing platform and confirmed by a real-time polymerase chain reaction. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and ingenuity pathway analysis were used to analyze RNA-seq results. Triptonide effectively inhibits the proliferation of human PCa cells PC3, DU145, and LNCap in vitro with their IC50 values as 11.961, 10.259, and 12.012 nM, respectively. Triptonide (10 mg/kg) potently inhibits the growth of PCa cell xenografts in vivo at an inhibition rate of over 97.95%. Treatment with triptonide (5 nM) significantly promotes cell apoptosis and retaining cell-cycle arrest in the G2/M phase. RNA-seq data revealed that total of 936 genes were upregulated or downregulated in triptonide treated. Moreover, the phosphorylation of mechanistic target of rapamycin (mTOR) and the downstream protein p70S6K were both inhibited, most obviously in PCa cells. Our findings suggest that triptonide can efficaciously suppress PCa growth in vitro and in vivo via inhibiting the phosphorylation of mTOR and the activities of related downstream signaling pathways.

Role of mammalian target of rapamycin signaling pathway in regulation of fatty acid oxidation in a preeclampsia-like mouse model treated with pravastatin.

Background:Fatty acid oxidation (FAO) disorder is involved in the pathogenesis of some cases of preeclampsia (PE). Several studies show that mammalian target of rapamycin (mTOR) signaling pathway is related to FAO. Pravastatin (Pra) can promote FAO in Nω-nitro-L-arginine methyl ester (L-NAME) PE-like mouse model in our previous study. This study aimed to investigate the effect of mTOR signaling pathway in PE-like model treated with Pra.Methods:Pregnant mice were randomly injected with L-NAME as PE-like model group or saline as control group respectively, from gestational 7th to 18th day. Giving Pra (L-NAME + Pra, Control + Pra, n = 8) or normal saline (NS; L-NAME + NS, Control + NS, n = 8) from gestational 8th to 18th day, the mice were sacrificed on day 18 and their liver and placental tissues were collected. Then the activation of mTOR and its substrates in the liver and placenta were detected. And the association between mTOR activation and serum free fatty acid (FFA) levels and the expression of long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) were evaluated using Pearson correlation test. Differences between groups were analyzed using independent t-test or one-way analysis of variance (ANOVA).Results:Both in the maternal liver and placenta, the activation of mTOR protein and its effect on substrates increased significantly in the L-NAME + NS group and decreased significantly in the L-NAME + Pra group. The p-mTOR/mTOR protein ratio decreased in the L-NAME + Pra group significantly than that in the L-NAME + NS group both in liver and placenta (liver: 0.74 ± 0.08 vs. 0.85 ± 0.06, t = 2.95, P < 0.05; placenta: 0.63 ± 0.06 vs. 0.77 ± 0.06, t = 4.64, P < 0.05). The activation of mTOR protein in the liver and placenta negatively correlated with the expression of LCHAD in the L-NAME + NS group (liver: r = −0.745, P < 0.05; placenta: r = −0.833, P < 0.05) and that in the maternal liver negatively correlated with the expression of LCHAD (r = −0.733, P < 0.05) and positively with the serum FFA levels (r = 0.841, P < 0.05) in the L-NAME + Pra group.Conclusion:The inhibition of mTOR signaling pathway might be involved in the regulation of FAO in mouse model treated with Pra.

Modern approaches to conservative therapy of polycystic kidney disease

Polycystic kidney disease (PKD) is a genetically determined pathological process associated with the formation and growth of cysts originating from the epithelial cells of the tubules and/or collecting tubes. PBP is represented by two main types - autosomal dominant (ADPKD) and autosomal recessive PKD (ARPKD), which are different diseases. The main causes of ADPKD are mutations of the PKD1 and PKD2 genes, which encode the formation of polycystin-1 and polycystin-2 proteins. ARPKD-linked mutation in the gene PKHD1, leads to total absence or defective synthesis of receptor protein primary cilia - fibrocystin. There are relationships between the structural and functional defects in the primary cilia and PBP. Mechanisms of cysts formation and growth include a) mutations of polycystines genes located on the cilia; b) increased activity of renal intracellular cAMP; c) vasopressin V2 receptors activation; d) violation of the tubular epithelium polarity (translocation of Na,K-ATPasa from basolateral to apical membrane); e) increased mTOR activity in epithelial cells lining renal cyst. The most promising directions of ADPKD therapy are blockade of vasopressin V2 receptors activation, inhibition of mTOR signaling pathways and reduction of intracellular cAMP level. The review presents clinical studies that assessed the effectiveness of named drugs in ADPKD.

Effect of cuecumin on mammalian target of rapamyein signaling pathway during ischemia-reperfusion injury in isolated rat lungs

Objective To evaluate the effect of curcumin on the mammalian target of rapamyein(mTOR)signaling pathway during ischemia-reperfusion(I/R)injury in isolated rat lungs. Methods Sixty-four clean-grade healthy male Sprague-Dawley rats, aged 3-4 months, weighing 250-320 g, were divided into 4 groups(n=16 each)using a random number table method: sham operation group(S group), I/R group, low-dose curcumin group(LC group)and high-dose curcumin group(HC group). The rats only received in vitro perfusion without ischemia in S group.Isolated rat lungs were subjected to 60 min of ischemia followed by 75-min reperfusion to establish the lung I/R injury model in I/R group.Curcumin 5 and 10 μmol/L were added to perfusion fluid from the beginning of reperfusion in LC and HC groups, respectively.Airway resistance(Res), lung compliance, perfusion flow(Flow)and pulmonary venous partial pressure of oxygen(PaO2)were recorded at 10 min of first perfusion(T0)and 15, 45 and 75 min of reperfusion(T1-3). Wet/dry lung weight ratio(W/D ratio)was measured at the end of reperfusion.The morphological structure and ultrastructure of lung tissues were observed by using a light microscope and a transmission electron microscope, respectively.The expression of mTOR, Tau protein, nuclear factor kappa B(NF-κB)and tumor necrosis factor-alpha(TNF-α)mRNA in lung tissues was detected by real-time polymerase chain reaction.The expression of mTOR, phosphorylated Tau protein(pS396 Tau protein), NF-κB and TNF-α protein in lung tissues was determined by Western blot. Results Compared with S group, Res at T1-3 and W/D ratio at T3 were significantly increased, lung compliance, Flow and PaO2 were decreased at T1-3, and the expression of mTOR, NF-κB and TNF-α protein and mRNA, Tau protein mRNA and pS396 Tau protein was up-regulated at T3 in I/R, LC and HC groups(P<0.05). Compared with I/R group, Res at T1-3 and W/D ratio at T3 were significantly decreased, lung compliance, Flow and PaO2 were increased at T1-3, and the expression of mTOR, NF-κB and TNF-α protein and mRNA, Tau protein mRNA and pS396 Tau protein was down-regulated at T3 in LC and HC groups(P<0.05). Compared with LC group, Res at T1-3 and W/D ratio at T3 were significantly decreased, lung compliance, Flow and PaO2 were increased at T1-3, and the expression of mTOR, NF-κB and TNF-α protein and mRNA, Tau protein mRNA and pS396 Tau protein was down-regulated at T3 in HC group(P<0.05). The microscopic examination showed that the injury to lung tissues was significantly attenuated in LC and HC groups as compared with I/R group. Conclusion The mechanism by which curcumin reduces I/R injury in isolated rat lungs is related to inhibiting mTOR signaling pathway. Key words: Curcumin; Lung; Reperfusion injury; Protein kinase C

Montelukast enhances cytocidal effects of carfilzomib in multiple myeloma by inhibiting mTOR pathway

ABSTRACT Montelukast is an anti-asthmatic medication, and has recently showed its inhibitory effects on the proliferation of cancers. The purpose of this study was to identify the cytotoxic effects of montelukast on multiple myeloma (MM) cells and the combination effects of montelukast and carfilzomib in the treatment of MM. Results revealed that montelukast induced a dose- and time-dependent cytotoxicity in MM cells lines and significantly suppressed the colony formation of myeloma cells. Furthermore, montelukast enhanced the cytotoxicity of carfilzomib in MM cell lines. This anti-tumor effect was associated with decreased c-Myc via the inhibition of mTOR signaling pathway. Moreover, the combination of montelukast and carfilzomib induced apoptosis of myeloma cells effectively, even in the presence of bone marrow stromal cells (BMSCs). It is more important to note that the co-treatment exhibited similar cytocidal effects in carfilzomib-resistant cell lines (U266R and 8226R). In addition, the combined effects were noted in two MM xenograft mice models and 7 cases of human CD138+ myeloma cells (4 newly diagnosed cases and 3 relapsed cases) with no cytotoxicity on peripheral blood mononuclear cells (PBMCs) from 5 healthy donors. Our data suggested that montelukast enhanced the cytotoxicity of carfilzomib in both carfilzomib-sensitive and carfilzomib-resistant MM cell lines. These findings may facilitate the development of therapeutic strategies and provide a promising therapeutic combination regimen for the treatment of refractory myeloma.

GLP-1 Improves Adipocyte Insulin Sensitivity Following Induction of Endoplasmic Reticulum Stress.

Glucagon-like peptide 1 (GLP-1) improves insulin resistance of adipose tissue in obese humans. However, the mechanism of this effect is unclear. Perturbation of endoplasmic reticulum (ER) homeostasis impairs insulin signaling. We hypothesized that GLP-1 could directly improve insulin signaling in ER-stressed adipocytes. Here, we examined the effects of GLP-1 on ER stress response in fat cells in an obese and insulin-resistant murine model. We found that GLP-1 analog liraglutide reduced ER stress related gene expression in visceral fat cells accompanied by improved systemic insulin tolerance. Consistently, GLP-1 decreased CHOP expression and increased insulin stimulated AKT phosphorylation (p-AKT) in thapsigargin, a ER stress inducer, treated white fat cells differentiated from visceral stromal vascular fraction. We further found blocking CHOP expression increased insulin stimulated p-AKT in ER-stressed fat cells. Of note, we found mTOR signaling pathway contributed to the expression of ATF4 and subsequently the CHOP expression in ER stress response, while GLP-1 inhibited mTOR activity as exemplified by elevated autophagosome formation and increased LC3II/LC3I ratio. These findings suggest that GLP-1 directly modulates the ER stress response partially via inhibiting mTOR signaling pathway, leading to increased insulin sensitivity in adipocytes.

MicroRNA-7450 regulates non-thermal plasma-induced chicken Sertoli cell apoptosis via adenosine monophosphate-activated protein kinase activation

Non-thermal plasma treatment is an emerging innovative technique with a wide range of biological applications. This study was conducted to investigate the effect of a non-thermal dielectric barrier discharge plasma technique on immature chicken Sertoli cell (SC) viability and the regulatory role of microRNA (miR)-7450. Results showed that plasma treatment increased SC apoptosis in a time- and dose-dependent manner. Plasma-induced SC apoptosis possibly resulted from the excess production of reactive oxygen species via the suppression of antioxidant defense systems and decreased cellular energy metabolism through the inhibition of adenosine triphosphate (ATP) release and respiratory enzyme activity in the mitochondria. In addition, plasma treatment downregulated miR-7450 expression and activated adenosine monophosphate-activated protein kinase α (AMPKα), which further inhibited mammalian target of rapamycin (mTOR) phosphorylation in SCs. A single-stranded synthetic miR-7450 antagomir disrupted mitochondrial membrane potential and decreased ATP level and mTOR phosphorylation by targeting the activation of AMPKα, which resulted in significant increases in SC lethality. A double-stranded synthetic miR-7450 agomir produced opposite effects on these parameters and ameliorated plasma-mediated apoptotic effects on SCs. Our findings suggest that miR-7450 is involved in the regulation of plasma-induced SC apoptosis through the activation of AMPKα and the further inhibition of mTOR signaling pathway.

Risk of hematological and gastrointestinal toxicities in patients with advanced neuroendocrine tumors treated with everolimus: A meta-analysis of phase 3 randomized controlled trials.

e16184Background: Neuroendocrine tumors (NET) are uncommon and can develop from multiple primary sites. Inhibition of mTOR signaling pathway has shown antiproliferative effects on NET and hence, ev...

Promising horizon to alleviate Alzeheimer’s disease pathological hallmarks via inhibiting mTOR signaling pathway: A new application for a commonplace analgesic

Alzheimer’s disease (AD) is a very prevalent and burdensome disease of elderlies but albeit extensive studies, mechanisms underlying its pathology and consequently its definite treatment is ambiguous. Intra and extra-cellular aggregation of abnormal proteins and impaired autophagy machinery, two closely related events taking place in AD brains proposed to be directly controlled by mTOR signaling pathway.On the other hand, tramadol that is a very well tolerated opioid analgesic has been revealed to inhibit mTOR upstream controllers through interaction with specific types of muscarinic, serotonergic, nicotinic and NMDA receptors, although it seems to induce the opposite effect via µ-opioid receptor.Putting all the pieces of experimental evidence together, we hypothesize that tramadol might alleviate AD pathological hallmarks at least in cellular level through decreasing activity of PI3K-AKT and ERK and also mTOR signaling pathways respectively and results in autophagy activation as well as tau-dephosphorylation.