1
|
Dai T, Gong J, Liu S. Prediction of molecular mechanism of processed ginseng in the treatment of heart failure based on network pharmacology and molecular docking technology. Medicine (Baltimore) 2023; 102:e36576. [PMID: 38065884 PMCID: PMC10713105 DOI: 10.1097/md.0000000000036576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Heart failure (HF) is the most common cardiovascular disease in clinics. Processed Panax ginseng C.A. Mey. Products have significant therapeutic effects on HF. Therefore, it is of great significance to explore the mechanism of action of Processed Panax ginseng C.A. Mey. Products in the treatment of HF. METHODS The saponin-like constituents of 3 different ginseng preparations were characterized by UPLC/QE-MS and the identified saponin constituents were subjected to network pharmacological analysis. Protein-protein interaction analyses of the targets of different ginseng preparations for the treatment of heart failure (HF) were performed using the STRING database, Gene Ontology enrichment analyses and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using the DAVID database, and the results of the network pharmacological analyses were validated using the Autodock software. Finally, the relative quantitative content of 5 major ginsenosides in 3 processed ginseng products was evaluated. RESULTS A total of 40 saponin compounds were identified based on mass spectrometry data. Network pharmacology and molecular docking analyses were used to predict the major targets of these sapions compounds and the key pathways mediating their anti-HF effects. After conducting a thorough screening, the study identified 5 primary ingredients of ginseng products ginsenoside Rh4, ginsenoside Rk3, ginsenoside Rk1, ginsenoside Rg5, and ginsenoside CK that can potentially target 22 essential proteins: EGFR, AKT1, ERBB2, STAT3, TNF, ESR1, MTOR, HRAS, MMP9, and PIK3CA, etc. Additionally, the Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that ginseng products can be beneficial in treating HF by interacting with pathways such as the PI3K-Akt signaling pathway, the TNF signaling pathway, the mTOR signaling pathway, and others. CONCLUSION The present study revealed that the treatment of HF with different processed ginseng products may be related to the regulation of the PI3K-Akt signaling pathway, TNF signaling pathway, apoptosis pathway, mTOR signaling pathway, etc, and that the key active ingredients may be concentrated in black ginseng, which provides a theoretical basis and direction for the further study of the mechanism of action of ginseng. This provides a theoretical basis and research direction for further in-depth study of its mechanism of action.
Collapse
Affiliation(s)
- Tingting Dai
- School of Pharmaceutical Sciences, Changchun University of Chinese Medicine, Changchun, China
| | - Jiyu Gong
- School of Pharmaceutical Sciences, Changchun University of Chinese Medicine, Changchun, China
| | - Shuying Liu
- Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun, China
| |
Collapse
|
2
|
Takenaka Y, Inoue I, Nakano T, Ikeda M, Kakinuma Y. Prolonged disturbance of proteostasis induces cellular senescence via temporal mitochondrial dysfunction and subsequent mitochondrial accumulation in human fibroblasts. FEBS J 2021; 289:1650-1667. [PMID: 34689411 DOI: 10.1111/febs.16249] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/15/2021] [Accepted: 10/22/2021] [Indexed: 01/18/2023]
Abstract
Proteolytic activity declines with age, resulting in the accumulation of aggregated proteins in aged organisms. To investigate how disturbance in proteostasis causes cellular senescence, we developed a stress-induced premature senescence (SIPS) model, in which normal human fibroblast MRC-5 cells were treated with the proteasome inhibitor MG132 or the vacuolar-type ATPase inhibitor bafilomycin A1 (BAFA1) for 5 days. Time-course studies revealed a significant increase in intracellular reactive oxygen species (ROS) and mitochondrial superoxide during and after drug treatment. Mitochondrial membrane potential initially decreased, suggesting temporal mitochondrial dysfunction during drug treatment, but was restored along with mitochondrial accumulation after drug treatment. AMP-activated protein kinase alpha was notably activated during treatment; thereafter, intracellular ATP levels significantly increased. SIPS induction by MG132 or BAFA1 was partially attenuated by co-treatment with vitamin E or rapamycin, in which the levels of ROS, mitochondrial accumulation, and protein aggregates were suppressed, implying the critical involvement of oxidative stress and mitochondrial function in SIPS progression. Rapamycin co-treatment also augmented the expression of HSP70 and activation of AKT, which could recover proteostasis and promote cell survival, respectively. Our study proposes a possible pathway from the disturbed proteostasis to cellular senescence via excess ROS production as well as functional and quantitative changes in mitochondria.
Collapse
Affiliation(s)
- Yasuhiro Takenaka
- Department of Physiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.,Department of Diabetes and Endocrinology, Saitama Medical University, Japan
| | - Ikuo Inoue
- Department of Diabetes and Endocrinology, Saitama Medical University, Japan
| | - Takanari Nakano
- Department of Biochemistry, Saitama Medical University, Japan
| | - Masaaki Ikeda
- Department of Physiology, Saitama Medical University, Japan
| | - Yoshihiko Kakinuma
- Department of Physiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
3
|
Novel Therapeutic Targets for the Treatment of Right Ventricular Remodeling: Insights from the Pulmonary Artery Banding Model. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18168297. [PMID: 34444046 PMCID: PMC8391744 DOI: 10.3390/ijerph18168297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 12/15/2022]
Abstract
Right ventricular (RV) function is the main determinant of the outcome of patients with pulmonary hypertension (PH). RV dysfunction develops gradually and worsens progressively over the course of PH, resulting in RV failure and premature death. Currently, approved therapies for the treatment of left ventricular failure are not established for the RV. Furthermore, the direct effects of specific vasoactive drugs for treatment of pulmonary arterial hypertension (PAH, Group 1 of PH) on RV are not fully investigated. Pulmonary artery banding (PAB) allows to study the pathogenesis of RV failure solely, thereby testing potential therapies independently of pulmonary vascular changes. This review aims to discuss recent studies of the mechanisms of RV remodeling and RV-directed therapies based on the PAB model.
Collapse
|
4
|
McNair BD, Schlatter JA, Cook RF, Yusifova M, Bruns DR. Inhibition of mTOR by rapamycin does not improve hypoxic pulmonary hypertension-induced right heart failure in old mice. Exp Gerontol 2021; 151:111395. [PMID: 33971279 DOI: 10.1016/j.exger.2021.111395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 02/07/2023]
Abstract
Inhibition of the mammalian target of rapamycin (mTOR) by rapamycin attenuates heart failure (HF) and age-associated changes in left ventricular (LV) function. Rapamycin has also been suggested as a therapy for pulmonary hypertension (PH) and concomitant right heart failure (PH-RHF) based on reports of elevated mTOR signaling in young models with PH. However, rapamycin has yet to be tested in the setting of aging, PH, and right heart disease despite the fact that RV function predicts survival in both age-related HF as well as several pulmonary disease states including PH. Thus we tested the hypothesis that rapamycin treatment would attenuate hypoxic PH-RHF in old mice using a mouse model of hypobaric hypoxia (HH)-induced PH and right ventricular (RV) remodeling. Exposure to HH resulted in significant loss of body weight which was exacerbated by rapamycin. HH elevated lung and RV weight, RV wall thickness as well as RV systolic dysfunction as evidenced by RV stroke volume and cardiac output. While rapamycin rescued pulmonary artery acceleration time in males, it generally did not improve other indexes cardiopulmonary remodeling or function. As expected, HH induced expression of hypoxia-regulated genes in the RV and the lungs; however, this transcriptional activation was attenuated by rapamycin, representing a potential mechanism by which rapamycin is detrimental in the aged RV in the setting of chronic hypoxia. Together, we demonstrate that rapamycin is not a viable therapeutic in hypoxic PH in old mice, likely due to exacerbated loss of body weight in this setting. We suggest that future efforts should take into consideration the differences between the RV and LV and the interaction between mTOR and hypoxia in the setting of age-related disease.
Collapse
Affiliation(s)
- Benjamin D McNair
- Division of Kinesiology & Health, University of Wyoming, Laramie, WY, United States of America
| | - Jacob A Schlatter
- Division of Kinesiology & Health, University of Wyoming, Laramie, WY, United States of America
| | - Ross F Cook
- Division of Kinesiology & Health, University of Wyoming, Laramie, WY, United States of America
| | - Musharraf Yusifova
- Division of Kinesiology & Health, University of Wyoming, Laramie, WY, United States of America
| | - Danielle R Bruns
- Division of Kinesiology & Health, University of Wyoming, Laramie, WY, United States of America.
| |
Collapse
|
5
|
Wu J, Zhong W, Zhang H, Yin Y. Mammalian Target of Rapamycin Signaling Enhances Ovalbumin-Induced Neutrophilic Airway Inflammation by Promoting Th17 Cell Polarization in Murine Noneosinophilic Asthma Model. PEDIATRIC ALLERGY IMMUNOLOGY AND PULMONOLOGY 2020; 33:25-32. [PMID: 33406024 DOI: 10.1089/ped.2019.1088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Background: T helper 17 (Th17) is regarded as key immune cell in the pathogenesis of noneosinophilic asthma (NEA) due to the recruitment of neutrophils into the airways. The mammalian target of rapamycin (mTOR) is an important signaling molecule that plays a critical role in immune regulation. This study focused on mTOR signaling pathway in the regulation of Th17-mediated neutrophilic airway inflammation. Methods: Ovalbumin (OVA) T cell receptor transgenic DO11.10 mice (DO11.10 mice) were used to establish NEA model, and few mice received specific mTORC1 inhibitor rapamycin (RAPA) before intranasal administration of OVA. The severity of airway inflammation was determined by differential cell counts in bronchoalveolar lavage (BAL) fluids and histopathologic lung analysis. The levels of various cytokines in BAL fluids and lung tissues were measured. To determine the role of mTORC1 signaling in Th17 differentiation, naive T cells from wild-type (WT) and TSC1 knockout (KO) mice were cultured in Th17 skewing condition with or without RAPA in vitro and the production of IL-17A was compared. Results: Treatment with RAPA markedly attenuated OVA-induced neutrophilic airway inflammation in DO11.10 mice. Also the production of IL-17A was inhibited without affecting the production of interferon-γ (IFN-γ) and IL-4 in lungs. Furthermore, RAPA suppressed differentiation of Th17 cells in vitro, whereas enhanced activity of mTORC1 promoted Th17 cell differentiation and increased the expression of Th17-related transcription factors RORγt and RORα. Conclusion: These results suggested that mTOR promoted Th17 cell polarization and enhanced OVA-induced neutrophilic airway inflammation in experimental NEA.
Collapse
Affiliation(s)
- Jinhong Wu
- Department of Pulmonary, Shanghai Children's Medical Center Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenwei Zhong
- Department of Pulmonary, Shanghai Children's Medical Center Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hao Zhang
- Department of Pulmonary, Shanghai Children's Medical Center Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yong Yin
- Department of Pulmonary, Shanghai Children's Medical Center Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| |
Collapse
|
6
|
Weiss A, Boehm M, Egemnazarov B, Grimminger F, Savai Pullamsetti S, Kwapiszewska G, Schermuly RT. Kinases as potential targets for treatment of pulmonary hypertension and right ventricular dysfunction. Br J Pharmacol 2020; 178:31-53. [PMID: 31709514 DOI: 10.1111/bph.14919] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/07/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022] Open
Abstract
Pulmonary hypertension (PH) is a progressive pulmonary vasculopathy that causes chronic right ventricular pressure overload and often leads to right ventricular failure. Various kinase inhibitors have been studied in the setting of PH and either improved or worsened the disease, highlighting the importance of understanding the specific role of the respective kinases in a spatiotemporal cellular context. In this review, we will summarize the knowledge on the role of kinases in PH and focus on druggable targets for which certain criteria are met: (a) deregulation of the kinase in PH; (b) small-molecule inhibitors are available (e.g. from the oncology field); (c) preclinical studies have shown their efficacy in PH models; and (d) when available, therapeutic exploitation in human PH has been initiated. Along this line, clinical considerations such as personalized medicine approaches to predict therapy response and adverse side events such as cardiotoxicity together with their clinical management are discussed. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.
Collapse
Affiliation(s)
- Astrid Weiss
- Department of Internal Medicine, Justus-Liebig University Giessen, Giessen, Germany.,German Center for Lung Research (DZL), Giessen, Germany
| | - Mario Boehm
- Department of Internal Medicine, Justus-Liebig University Giessen, Giessen, Germany.,German Center for Lung Research (DZL), Giessen, Germany
| | | | - Friedrich Grimminger
- Department of Internal Medicine, Justus-Liebig University Giessen, Giessen, Germany.,German Center for Lung Research (DZL), Giessen, Germany
| | | | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria.,Otto Loewi Center, Physiology, Medical University of Graz, Graz, Austria
| | - Ralph T Schermuly
- Department of Internal Medicine, Justus-Liebig University Giessen, Giessen, Germany
| |
Collapse
|
7
|
Gao G, Chen W, Yan M, Liu J, Luo H, Wang C, Yang P. Rapamycin regulates the balance between cardiomyocyte apoptosis and autophagy in chronic heart failure by inhibiting mTOR signaling. Int J Mol Med 2019; 45:195-209. [PMID: 31746373 PMCID: PMC6889932 DOI: 10.3892/ijmm.2019.4407] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/17/2019] [Indexed: 12/18/2022] Open
Abstract
The progressive loss of cardiomyocytes caused by cell death leads to cardiac dysfunction and heart failure (HF). Rapamycin has been shown to be cardioprotective in pressure-overloaded and ischemic heart diseases by regulating the mechanistic target of rapamycin (mTOR) signaling network. However, the impact of rapamycin on cardiomyocyte death in chronic HF remains undetermined. Therefore, in the current study we addressed this issue using a rat myocardial infarction (MI)-induced chronic HF model induced by ligating the coronary artery. Following surgery, rats were randomly divided into six groups, including the sham-, vehicle- and rapamycin-operated groups, at 8 or 12 weeks post-MI. A period of 4 weeks after MI induction, the rats were treated with rapamycin (1.4 mg-kg-day) or vehicle for 4 weeks. Cardiac function was determined using echocardiography, the rats were subsequently euthanized and myocardial tissues were harvested for histological and biochemical analyses. In the cell culture experiments with H9c2 rat cardiomyocytes, apoptosis was induced using angiotensin II (100 nM; 24 h). Cardiomyocyte apoptosis and autophagy were assessed via measuring apoptosis- and autophagy-associated proteins. The activities of mTOR complex 1 (mTORC1) and mTORC2 were evaluated using the phosphorylation states of ribosomal S6 protein and Akt, respectively. The activity of the endoplasmic reticulum (ER) stress pathway was determined using the levels of GRP78, caspase-12, phospho-JNK and DDIT3. Echocardiographic and histological measurements indicated that rapamycin treatment improved cardiac function and inhibited cardiac remodeling at 8 weeks post-MI. Additionally, rapamycin prevented cardiomyocyte apoptosis and promoted autophagy at 8 weeks post-MI. Rapamycin treatment for 4 weeks inhibited the mTOR and ER stress pathways. Furthermore, rapamycin prevented angiotensin II-induced H9c2 cell apoptosis and promoted autophagy by inhibiting the mTORC1 and ER stress pathways. These results demonstrated that rapamycin reduced cardiomyocyte apoptosis and promoted cardiomyocyte autophagy, by regulating the crosstalk between the mTOR and ER stress pathways in chronic HF.
Collapse
Affiliation(s)
- Guangyuan Gao
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Weiwei Chen
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Mengjie Yan
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Jinsha Liu
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Huiling Luo
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Chang Wang
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Ping Yang
- Department of Cardiology, China‑Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| |
Collapse
|
8
|
Xu X, Kobayashi S, Timm D, Huang Y, Zhao F, Shou W, Liang Q. Enhanced mTOR complex 1 signaling attenuates diabetic cardiac injury in OVE26 mice. FASEB J 2019; 33:12800-12811. [PMID: 31469601 DOI: 10.1096/fj.201901206r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The protein kinase mechanistic target of rapamycin (mTOR) performs diverse cellular functions through 2 distinct multiprotein complexes, mTOR complex (mTORC)1 and 2. Numerous studies using rapamycin, an mTORC1 inhibitor, have implicated a role for mTORC1 in several types of heart disease. People with diabetes are more susceptible to heart failure. mTORC1 activity is increased in the diabetic heart, but its functional significance remains controversial. To investigate the role of mTORC1 in the diabetic heart, we crossed OVE26 type 1 diabetic mice with transgenic mice expressing a constitutively active mTOR (mTORca) or kinase-dead mTOR (mTORkd) in the heart. The expression of mTORca or mTORkd affected only mTORC1 but not mTORC2 activities, with corresponding changes in the activities of autophagy, a cellular degradation pathway negatively regulated by mTORC1. Diabetic cardiac damage in OVE26 mice was dramatically reduced by mTORca but exacerbated by mTORkd expression as assessed by changes in cardiac function, oxidative stress, and myocyte apoptosis. These findings demonstrated that the enhanced mTORC1 signaling in the OVE26 diabetic heart was an adaptive response that limited cardiac dysfunction, suggesting that manipulations that enhance mTORC1 activity may reduce diabetic cardiac injury, in sharp contrast to the results previously obtained with rapamycin.-Xu, X., Kobayashi, S., Timm, D., Huang, Y., Zhao, F., Shou, W., Liang, Q. Enhanced mTOR complex 1 signaling attenuates diabetic cardiac injury in OVE26 mice.
Collapse
Affiliation(s)
- Xianmin Xu
- Sanford Research, Sioux Falls, South Dakota, USA
| | - Satoru Kobayashi
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Derek Timm
- Sanford Research, Sioux Falls, South Dakota, USA
| | - Yuan Huang
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Fengyi Zhao
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Weinian Shou
- Department of Pediatrics, Riley Heart Center, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Qiangrong Liang
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| |
Collapse
|
9
|
Wang N, Wang M. Dexmedetomidine suppresses sevoflurane anesthesia-induced neuroinflammation through activation of the PI3K/Akt/mTOR pathway. BMC Anesthesiol 2019; 19:134. [PMID: 31351473 PMCID: PMC6661092 DOI: 10.1186/s12871-019-0808-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 07/18/2019] [Indexed: 11/17/2022] Open
Abstract
Background Sevoflurane, an inhalational general anesthetic, has become one of the most widely used inhalational anesthetics in surgery. However, previous studies have found that sevoflurane anesthesia can trigger an inflammatory response, resulting in secondary damage. Dexmedetomidine (DEX), a highly-selective α adrenergic receptor agonist, is widely used as an anesthetic adjuvant in the clinic. In this study we investigated whether DEX was able to suppress sevoflurane-induced neuroinflammation. Methods The aim was to determine the mechanism of action of the suppressive effect of DEX using a rat model. Rats were randomly divided into a control group (n = 10), low-dose sevoflurane group (L-Sev; n = 10), high-dose sevoflurane group (H-Sev; n = 10), vehicle group (n = 10), DEX group (n = 10) and DEX + LY294002 (a specific inhibitor of PI3K) group (n = 10). The rats in vehicle, DEX and DEX + LY294002 groups were in the presence of high-dose sevoflurane exposure. Western blotting was used to measure the expression of proinflammatory cytokines (IL-6, IL-8, TNF-α) and the activity level of the phosphatidylinositol 3-hydroxy kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway. Results We found that sevoflurane anesthesia induced an increase in the levels of pro-inflammatory cytokines, while decreasing activation of the PI3K/Akt/mTOR pathway in both the cortex and hippocampus of rats. Treatment with DEX reduced pro-inflammatory cytokine levels and prevented inactivation of the PI3K/Akt/mTOR pathway. Moreover, LY294002, an inhibitor of the PI3K/Akt/mTOR pathway, reduced the anti-inflammatory activity of DEX. Conclusions These data suggest that the PI3K/Akt/mTOR pathway contributes to sevoflurane-induced neuroinflammation and that activation of PI3K/Akt/mTOR signaling by DEX could help reduce the neuroinflammatory effects of sevoflurane.
Collapse
Affiliation(s)
- Nan Wang
- Department of Anesthesiology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Dalian Medical University Clinical Oncology College, Shenyang, 110042, Liaoning, China
| | - Mingyu Wang
- Department of Anesthesiology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Dalian Medical University Clinical Oncology College, Shenyang, 110042, Liaoning, China.
| |
Collapse
|
10
|
Roberti SL, Higa R, White V, Powell TL, Jansson T, Jawerbaum A. Critical role of mTOR, PPARγ and PPARδ signaling in regulating early pregnancy decidual function, embryo viability and feto-placental growth. Mol Hum Reprod 2019. [PMID: 29538677 DOI: 10.1093/molehr/gay013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
STUDY QUESTION What are the consequences of inhibiting mTOR, the mechanistic target of rapamycin (mTOR), and the peroxisome proliferator activated receptor gamma (PPARγ) and PPARδ pathways in the early post-implantation period on decidual function, embryo viability and feto-placental growth in the rat? SUMMARY ANSWER mTOR inhibition from Days 7 to 9 of pregnancy in rats caused decidual PPARγ and PPARδ upregulation on Day 9 of pregnancy and resulted in embryo resorption by Day 14 of pregnancy. PPARγ and PPARδ inhibition differentially affected decidual mTOR signaling and levels of target proteins relevant to lipid histotrophic nutrition and led to reduced feto-placental weights on Day 14 of pregnancy. WHAT IS KNOWN ALREADY Although mTOR, PPARγ and PPARδ are nutrient sensors important during implantation, the role of these signaling pathways in decidual function and how they interact in the early post-implantation period are unknown. Perilipin 2 (PLIN2) and fatty acid binding protein 4 (FABP4), two adipogenic proteins involved in lipid histotrophic nutrition, are targets of mTOR and PPAR signaling pathways in a variety of tissues. STUDY DESIGN, SIZE, DURATION Rapamycin (mTOR inhibitor, 0.75 mg/kg, sc), T0070907 (PPARγ inhibitor, 0.001 mg/kg, sc), GSK0660 (PPARδ inhibitor, 0.1 mg/kg, sc) or vehicle was injected daily to pregnant rats from Days 7 to 9 of pregnancy and the studies were performed on Day 9 of pregnancy (n = 7 per group) or Day 14 of pregnancy (n = 7 per group). PARTICIPANTS/MATERIALS, SETTING, METHODS On Day 9 of pregnancy, rat decidua were collected and prepared for western blot and immunohistochemical studies. On Day 14 of pregnancy, the resorption rate, number of viable fetuses, crown-rump length and placental and decidual weights were determined. MAIN RESULTS AND THE ROLE OF CHANCE Inhibition of mTOR in the early post-implantation period led to a reduction in FABP4 protein levels, an increase in PLIN2 levels and an upregulation of PPARγ and PPARδ in 9-day-pregnant rat decidua. Most embryos were viable on Day 9 of pregnancy but had resorbed by Day 14 of pregnancy. This denotes a key function of mTOR in the post-implantation period and suggests that activation of PPAR signaling was insufficient to compensate for impaired nutritional/survival signaling induced by mTOR inhibition. Inhibition of PPARγ signaling resulted in decreased decidual PLIN2 and FABP4 protein expression as well as in inhibition of decidual mTOR signaling in Day 9 of pregnancy. This treatment also reduced feto-placental growth on Day 14 of pregnancy, revealing the relevance of PPARγ signaling in sustaining post-implantation growth. Moreover, following inhibition of PPARδ, PLIN2 levels were decreased and mTOR complex 1 and 2 signaling was altered in decidua on Day 9 of pregnancy. On Day 14 of pregnancy, PPARδ inhibition caused reduced feto-placental weight, increased decidual weight and increased resorption rate, suggesting a key role of PPARδ in sustaining post-implantation development. LARGE SCALE DATA Not applicable. LIMITATIONS, REASONS FOR CAUTION This is an in vivo animal study and the relevance of the results for humans remains to be established. WIDER IMPLICATIONS OF THE FINDINGS The early post-implantation period is a critical window of development and changes in the intrauterine environment may cause embryo resorption and lead to placental and fetal growth restriction. mTOR, PPARγ and PPARδ signaling are decidual nutrient sensors with extensive cross-talk that regulates adipogenic proteins involved in histotrophic nutrition and important for embryo viability and early placental and fetal development and growth. STUDY FUNDING/COMPETING INTEREST(S) Funding was provided by the Agencia Nacional de Promoción Científica y Tecnológica de Argentina (PICT 2014-411 and PICT 2015-0130), and by the International Cooperation (Grants CONICET-NIH-2014 and CONICET-NIH-2017) to A.J. and T.J. The authors have no conflicts of interest.
Collapse
Affiliation(s)
- Sabrina L Roberti
- Universidad de Buenos Aires, Facultad de Medicina, Paraguay 2155, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Laboratory of Reproduction and Metabolism, CEFYBO, 1121 CABA, Buenos Aires, Argentina
| | - Romina Higa
- Universidad de Buenos Aires, Facultad de Medicina, Paraguay 2155, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Laboratory of Reproduction and Metabolism, CEFYBO, 1121 CABA, Buenos Aires, Argentina
| | - Verónica White
- Universidad de Buenos Aires, Facultad de Medicina, Paraguay 2155, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Laboratory of Reproduction and Metabolism, CEFYBO, 1121 CABA, Buenos Aires, Argentina
| | - Theresa L Powell
- Section of Neonatology, Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA.,Division of Reproductive Sciences, Department of OB/GYN, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Thomas Jansson
- Division of Reproductive Sciences, Department of OB/GYN, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Alicia Jawerbaum
- Universidad de Buenos Aires, Facultad de Medicina, Paraguay 2155, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Laboratory of Reproduction and Metabolism, CEFYBO, 1121 CABA, Buenos Aires, Argentina
| |
Collapse
|
11
|
Fu X, Sun X, Zhang L, Jin Y, Chai R, Yang L, Zhang A, Liu X, Bai X, Li J, Wang H, Gao J. Tuberous sclerosis complex-mediated mTORC1 overactivation promotes age-related hearing loss. J Clin Invest 2018; 128:4938-4955. [PMID: 30247156 DOI: 10.1172/jci98058] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 08/08/2018] [Indexed: 12/29/2022] Open
Abstract
The underlying molecular mechanisms of age-related hearing loss (ARHL) in humans and many strains of mice have not been fully characterized. This common age-related disorder is assumed to be closely associated with oxidative stress. Here, we demonstrate that mTORC1 signaling is highly and specifically activated in the cochlear neurosensory epithelium (NSE) in aging mice, and rapamycin injection prevents ARHL. To further examine the specific role of mTORC1 signaling in ARHL, we generated murine models with NSE-specific deletions of Raptor or Tsc1, regulators of mTORC1 signaling. Raptor-cKO mice developed hearing loss considerably more slowly than WT littermates. Conversely, Tsc1 loss led to the early-onset death of cochlear hair cells and consequently accelerated hearing loss. Tsc1-cKO cochleae showed features of oxidative stress and impaired antioxidant defenses. Treatment with rapamycin and the antioxidant N-acetylcysteine rescued Tsc1-cKO hair cells from injury in vivo. In addition, we identified the peroxisome as the initial signaling organelle involved in the regulation of mTORC1 signaling in cochlear hair cells. In summary, our findings identify overactive mTORC1 signaling as one of the critical causes of ARHL and suggest that reduction of mTORC1 activity in cochlear hair cells may be a potential strategy to prevent ARHL.
Collapse
Affiliation(s)
- Xiaolong Fu
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Xiaoyang Sun
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Linqing Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Yecheng Jin
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Renjie Chai
- Key Laboratory for Development Genes and Human Disease, Southeast University, Nanjing, China
| | - Lili Yang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Aizhen Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China.,Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Xiangguo Liu
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Xiaochun Bai
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jianfeng Li
- Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Jiangang Gao
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| |
Collapse
|
12
|
Xiao YF, Zeng ZX, Guan XH, Wang LF, Wang CJ, Shi H, Shou W, Deng KY, Xin HB. FKBP12.6 protects heart from AngII-induced hypertrophy through inhibiting Ca 2+ /calmodulin-mediated signalling pathways in vivo and in vitro. J Cell Mol Med 2018; 22:3638-3651. [PMID: 29682889 PMCID: PMC6010737 DOI: 10.1111/jcmm.13645] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/08/2018] [Indexed: 12/12/2022] Open
Abstract
We previously observed that disruption of FK506‐binding protein 12.6 (FKBP12.6) gene resulted in cardiac hypertrophy in male mice. Studies showed that overexpression of FKBP12.6 attenuated thoracic aortic constriction (TAC)‐induced cardiac hypertrophy in mice, whereas the adenovirus‐mediated overexpression of FKBP12.6 induced hypertrophy and apoptosis in cultured neonatal cardiomyocytes, indicating that the role of FKBP12.6 in cardiac hypertrophy is still controversial. In this study, we aimed to investigate the roles and mechanisms of FKBP12.6 in angiotensin II (AngII)‐induced cardiac hypertrophy using various transgenic mouse models in vivo and in vitro. FKBP12.6 knockout (FKBP12.6−/−) mice and cardiac‐specific FKBP12.6 overexpressing (FKBP12.6 TG) mice were infused with AngII (1500 ng/kg/min) for 14 days subcutaneously by implantation of an osmotic mini‐pump. The results showed that FKBP12.6 deficiency aggravated AngII‐induced cardiac hypertrophy, while cardiac‐specific overexpression of FKBP12.6 prevented hearts from the hypertrophic response to AngII stimulation in mice. Consistent with the results in vivo, overexpression of FKBP12.6 in H9c2 cells significantly repressed the AngII‐induced cardiomyocyte hypertrophy, seen as reductions in the cell sizes and the expressions of hypertrophic genes. Furthermore, we demonstrated that the protection of FKBP12.6 on AngII‐induced cardiac hypertrophy was involved in reducing the concentration of intracellular Ca2+ ([Ca2+]i), in which the protein significantly inhibited the key Ca2+/calmodulin‐dependent signalling pathways such as calcineurin/cardiac form of nuclear factor of activated T cells 4 (NFATc4), calmodulin kinaseII (CaMKII)/MEF‐2, AKT/Glycogen synthase kinase 3β (GSK3β)/NFATc4 and AKT/mTOR signalling pathways. Our study demonstrated that FKBP12.6 protects heart from AngII‐induced cardiac hypertrophy through inhibiting Ca2+/calmodulin‐mediated signalling pathways.
Collapse
Affiliation(s)
- Yun-Fei Xiao
- Institute of Translational Medicine, Nanchang University, Nanchang, China.,School of Life Science, Nanchang University, Nanchang, China
| | - Zhi-Xiong Zeng
- Institute of Translational Medicine, Nanchang University, Nanchang, China.,School of Life Science, Nanchang University, Nanchang, China
| | - Xiao-Hui Guan
- Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Ling-Fang Wang
- Institute of Translational Medicine, Nanchang University, Nanchang, China.,School of Life Science, Nanchang University, Nanchang, China
| | - Chan-Juan Wang
- Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Huidong Shi
- Georgia Cancer Center, Augusta University, Augusta, GA, USA
| | - Weinian Shou
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ke-Yu Deng
- Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Hong-Bo Xin
- Institute of Translational Medicine, Nanchang University, Nanchang, China.,School of Life Science, Nanchang University, Nanchang, China
| |
Collapse
|
13
|
Zhou L, Miao K, Yin B, Li H, Fan J, Zhu Y, Ba H, Zhang Z, Chen F, Wang J, Zhao C, Li Z, Wang DW. Cardioprotective Role of Myeloid-Derived Suppressor Cells in Heart Failure. Circulation 2018; 138:181-197. [PMID: 29437117 DOI: 10.1161/circulationaha.117.030811] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/16/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells that expand in cancer, inflammation, and infection and negatively regulate inflammation and the immune response. Heart failure (HF) is a complex clinical syndrome wherein inflammation induction and incomplete resolution can potentially contribute to HF development and progression. However, the role of MDSCs in HF remains unclear. METHODS The percentage of MDSCs in patients with HF and in mice with pressure overload-induced HF using isoproterenol infusion or transverse aortic constriction (TAC) was detected by flow cytometry. The effects of MDSCs on isoproterenol- or TAC-induced HF were observed on depleting MDSCs with 5-fluorouracil (50 mg/kg) or gemcitabine (120 mg/kg), transferring purified MDSCs, or enhancing endogenous MDSCs with rapamycin (2 mg·kg-1·d-1). Hypertrophic markers and inflammatory factors were detected by ELISA, real-time polymerase chain reaction, or Western blot. Cardiac functions were determined by echocardiography and hemodynamic analysis. RESULTS The percentage of human leukocyte antigen-D-related (HLA-DR)-CD33+CD11b+ MDSCs in the blood of patients with HF was significantly increased and positively correlated with disease severity and increased plasma levels of cytokines, including interleukin-6, interleukin-10, and transforming growth factor-β. Furthermore, MDSCs derived from patients with HF inhibited T-cell proliferation and interferon-γ secretion. Similar results were observed in TAC- and isoproterenol-induced HF in mice. Pharmaceutical depletion of MDSCs significantly exacerbated isoproterenol- and TAC-induced pathological cardiac remodeling and inflammation, whereas adoptive transfer of MDSCs prominently rescued isoproterenol- and TAC-induced HF. Consistently, administration of rapamycin significantly increased endogenous MDSCs by suppressing their differentiation and improved isoproterenol- and TAC-induced HF, but MDSC depletion mostly blocked beneficial rapamycin-mediated effects. Mechanistically, MDSC-secreted molecules suppressed isoproterenol-induced hypertrophy and proinflammatory gene expression in cardiomyocytes in a coculture system. Neutralization of interleukin-10 blunted both monocytic MDSC- and granulocytic MDSC-mediated anti-inflammatory and antihypertrophic effects, but treatment with a nitric oxide inhibitor only partially blocked the antihypertrophic effect of monocytic MDSCs. CONCLUSIONS Our findings revealed a cardioprotective role of MDSCs in HF by their antihypertrophic effects on cardiomyocytes and anti-inflammatory effects through interleukin-10 and nitric oxide. Pharmacological targeting of MDSCs by rapamycin constitutes a promising therapeutic strategy for HF.
Collapse
Affiliation(s)
- Ling Zhou
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.)
| | - Kun Miao
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.)
| | - Bingjiao Yin
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.).,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huaping Li
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.)
| | - Jiahui Fan
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.)
| | - Yazhen Zhu
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.).,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongping Ba
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.).,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zunyue Zhang
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.).,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Chen
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.).,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Wang
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.).,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunxia Zhao
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.)
| | - Zhuoya Li
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.) .,Department of Immunology, School of Basic Medicine (B.Y., Y.Z., H.B., Z.Z., F.C., J.W., and Z.L.), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Tongji Hospital (L.Z., K.M., H.L., J.F., C.Z., D.W.W.)
| |
Collapse
|
14
|
Giguère V. Canonical signaling and nuclear activity of mTOR-a teamwork effort to regulate metabolism and cell growth. FEBS J 2018; 285:1572-1588. [PMID: 29337437 DOI: 10.1111/febs.14384] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/21/2017] [Accepted: 01/10/2018] [Indexed: 01/07/2023]
Abstract
Mechanistic (or mammalian) target of rapamycin (mTOR) is a kinase that regulates almost all functions related to cell growth and metabolism in response to extra- and intracellular stimuli, such as availability of nutrients, the presence of growth factors, or the energy status of the cell. As part of two distinct protein complexes, mTORC1 and mTORC2, the kinase has been shown to influence cell growth and proliferation by controlling ribosome biogenesis, mRNA translation, carbohydrate and lipid metabolism, protein degradation, autophagy as well as microtubule and actin dynamics. In addition to these well-characterized functions, mTOR can also influence gene transcription. While most studies focused on investigating how canonical mTOR signaling regulates the activity of transcription factors outside the nucleus, recent findings point to a more direct role for mTOR as a transcription factor operating on chromatin in the nucleus. In particular, recent genome-wide identification of mTOR targets on chromatin reveals that its activities in the nucleus and cytoplasm are functionally and biologically linked, thus uncovering a novel paradigm in mTOR function.
Collapse
Affiliation(s)
- Vincent Giguère
- Departments of Biochemistry, Medicine and Oncology, Faculty of Medicine, Goodman Cancer Research Centre, McGill University, Montréal, Canada
| |
Collapse
|
15
|
Suhara T, Baba Y, Shimada BK, Higa JK, Matsui T. The mTOR Signaling Pathway in Myocardial Dysfunction in Type 2 Diabetes Mellitus. Curr Diab Rep 2017; 17:38. [PMID: 28434143 PMCID: PMC8219468 DOI: 10.1007/s11892-017-0865-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW T2DM (type 2 diabetes mellitus) is a risk factor for heart failure. The mTOR (mechanistic target of rapamycin) is a key mediator of the insulin signaling pathway. We will discuss the role of mTOR in myocardial dysfunction in T2DM. RECENT FINDINGS In T2DM, chronically activated mTOR induces multiple pathological events, including a negative feedback loop that suppresses IRS (insulin receptor substrate)-1. While short-term treatment with rapamycin, an mTOR inhibitor, is a promising strategy for cardiac diseases such as acute myocardial infarction and cardiac hypertrophy in T2DM, there are many concerns about chronic usage of rapamycin. Two mTOR complexes, mTORC1 and mTORC2, affect many molecules and processes via distinct signaling pathways that regulate cardiomyocyte function and survival. Understanding mechanisms underlying mTOR-mediated pathophysiological features in the heart is essential for developing effective therapies for cardiac diseases in the context of T2DM.
Collapse
Affiliation(s)
- Tomohiro Suhara
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
- Department of Anesthesiology, Keio University School of Medicine, Tokyo, Japan
| | - Yuichi Baba
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
- Department of Cardiology and Geriatrics, Kochi Medical School, Kochi University, Kochi, Japan
| | - Briana K Shimada
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
| | - Jason K Higa
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
| | - Takashi Matsui
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA.
| |
Collapse
|
16
|
de Melo BL, Vieira SS, Antônio EL, Dos Santos LFN, Portes LA, Feliciano RS, de Oliveira HA, Silva JA, de Carvalho PDTC, Tucci PJF, Serra AJ. Exercise Training Attenuates Right Ventricular Remodeling in Rats with Pulmonary Arterial Stenosis. Front Physiol 2016; 7:541. [PMID: 27994552 PMCID: PMC5136544 DOI: 10.3389/fphys.2016.00541] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/27/2016] [Indexed: 12/04/2022] Open
Abstract
Introduction: Pulmonary arterial stenosis (PAS) is a congenital defect that causes outflow tract obstruction of the right ventricle (RV). Currently, negative issues are reported in the PAS management: not all patients may be eligible to surgeries; there is often the need for another surgery during passage to adulthood; patients with mild stenosis may have later cardiac adverse repercussions. Thus, the search for approaches to counteract the long-term PAS effects showed to be a current target. At the study herein, we evaluated the cardioprotective role of exercise training in rats submitted to PAS for 9 weeks. Methods and Results: Exercise resulted in improved physical fitness and systolic RV function. Exercise also blunted concentric cavity changes, diastolic dysfunction, and fibrosis induced by PAS. Exercise additional benefits were also reported in a pro-survival signal, in which there were increased Akt1 activity and normalized myocardial apoptosis. These findings were accompanied by microRNA-1 downregulation and microRNA-21 upregulation. Moreover, exercise was associated with a higher myocardial abundance of the sarcomeric protein α-MHC and proteins that modulate calcium handling—ryanodine receptor and Serca 2, supporting the potential role of exercise in improving myocardial performance. Conclusion: Our results represent the first demonstration that exercise can attenuate the RV remodeling in an experimental PAS. The cardioprotective effects were associated with positive modulation of RV function, survival signaling pathway, apoptosis, and proteins involved in the regulation of myocardial contractility.
Collapse
Affiliation(s)
- Brunno Lemes de Melo
- Cardiac Physiology Laboratory, Federal University of São Paulo São Paulo, Brazil
| | - Stella S Vieira
- Cardiac Physiology Laboratory, Federal University of São Paulo São Paulo, Brazil
| | - Ednei L Antônio
- Cardiac Physiology Laboratory, Federal University of São Paulo São Paulo, Brazil
| | - Luís F N Dos Santos
- Cardiac Physiology Laboratory, Federal University of São Paulo São Paulo, Brazil
| | - Leslie A Portes
- Cardiac Physiology Laboratory, Federal University of São Paulo São Paulo, Brazil
| | | | | | - José A Silva
- Biophotonic Laboratory, Nove de Julho University São Paulo, Brazil
| | | | - Paulo J F Tucci
- Cardiac Physiology Laboratory, Federal University of São Paulo São Paulo, Brazil
| | - Andrey J Serra
- Cardiac Physiology Laboratory, Federal University of São PauloSão Paulo, Brazil; Biophotonic Laboratory, Nove de Julho UniversitySão Paulo, Brazil
| |
Collapse
|
17
|
Deng XS, Meng X, Song R, Fullerton D, Jaggers J. Rapamycin Decreases the Osteogenic Response in Aortic Valve Interstitial Cells Through the Stat3 Pathway. Ann Thorac Surg 2016; 102:1229-38. [PMID: 27209607 DOI: 10.1016/j.athoracsur.2016.03.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 11/10/2015] [Accepted: 03/14/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Calcific aortic valve disease (CAVD) is an age-related and slowly progressive valvular disorder. We have previously found that the increased inflammatory and osteogenic responses to Toll-like receptor 4 (TLR4) stimulation is correlated with lower signal transducer and activator of transcription 3 (Stat3) activity in aortic valve interstitial cells (AVICs). Rapamycin, a drug used clinically, induces feedback activation of Akt. Akt in turn may upregulate Stat3. Therefore we hypothesized that rapamycin will decrease TLR4-induced osteogenic response in human AVICs through modulation of Stat3 activity. METHODS AVICs were isolated from normal valves taken from the explanted hearts of patients undergoing transplantation. Cells were treated with TLR4 ligand lipopolysaccharide (LPS) or rapamycin, or both. The osteogenic markers runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), and bone morphogenetic protein 2 (BMP-2), as well as activation of Stat3 and its associated signaling molecules, were analyzed. RESULTS LPS induces the expression of RUNX2, ALP, and BMP-2. Rapamycin decreased both the baseline and LPS-induced expression of RUNX2, ALP, and BMP-2. Rapamycin also decreased calcium deposit formation. Rapamycin activated both Stat3 and Akt in AVICs. Suppression of Akt resulted in abolishment of Stat3 activation. Inhibition of Stat3 enhanced expression of RUNX2, ALP, and BMP-2 at baseline and in response to LPS. CONCLUSIONS Rapamycin inhibits TLR4-induced osteogenic responses in AVICs by activation of Stat3 through Akt. Rapamycin may alleviate inflammation-induced initiation and progression of CAVD.
Collapse
Affiliation(s)
- Xin-Sheng Deng
- Department of Cardiothoracic Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Xianzhong Meng
- Department of Cardiothoracic Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Rui Song
- Department of Cardiothoracic Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - David Fullerton
- Department of Cardiothoracic Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - James Jaggers
- Department of Cardiothoracic Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
| |
Collapse
|
18
|
Yan S, Che Y, Jiang X. Proteasome inhibition attenuates rasfonin-induced autophagy concurring with the upregulation of caspase-dependent apoptosis. Mycology 2016; 7:29-35. [PMID: 30123613 PMCID: PMC6059125 DOI: 10.1080/21501203.2016.1147091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/23/2016] [Indexed: 02/06/2023] Open
Abstract
Two major protein quality control mechanisms exist in eukaryotic cells, the ubiquitin-proteasome system (UPS) and the autophagy–lysosome system. Generally, the inhibition of UPS is believed to enhance autophagic pathway; nevertheless, the crosstalk between these two degradation systems may be much more complicated. Rasfonin, a 2-pyrone derivative of fungal secondary metabolites, is demonstrated to have the antitumor effect and can function as an autophagy inducer. Here, we reported that rasfonin activated multiple cell death pathways, including caspase-dependent apoptosis. Using electroscopy and microscopy, we observed rasfonin increased the formation of autophagosome. In immunoblotting assay, rasfonin enhanced autophagic flux concomitant with the upregulation of ubiquitination. MG132, an inhibitor of proteasome, attenuated rasfonin-dependent autophagy, whereas its presentation stimulated rasfonin-induced cleavage of poly (ADP-ribose) polymerase, a marker of caspase-dependent apoptosis. Together, we demonstrated that rasfonin induced the activation of both UPS and autophagic pathway, and the inhibition of UPS attenuated rasfonin-induced autophagy and enhanced the cytotoxicity of rasonin by upregulation of caspase-dependent apoptosis.
Collapse
Affiliation(s)
- Siyuan Yan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing100101, China.,University of Chinese Academy of Sciences, Beijing100039, China
| | - Yongsheng Che
- State Key Laboratory of Toxicology & Medical Countermeasures, Beijing Institute of Pharmacology & Toxicology, AMMS, Beijing100850, China
| | - Xuejun Jiang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing100101, China
| |
Collapse
|
19
|
Sundararaj K, Pleasant DL, Moschella PC, Panneerselvam K, Balasubramanian S, Kuppuswamy D. mTOR Complexes Repress Hypertrophic Agonist-Stimulated Expression of Connective Tissue Growth Factor in Adult Cardiac Muscle Cells. J Cardiovasc Pharmacol 2016; 67:110-20. [PMID: 26371948 PMCID: PMC7334753 DOI: 10.1097/fjc.0000000000000322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Connective tissue growth factor (CTGF) is a fibrogenic cytokine that promotes fibrosis in various organs. In the heart, both cardiomyocytes (CM) and cardiac fibroblasts have been reported as a source of CTGF expression, aiding cardiac fibrosis. Although the mammalian target of rapamycin (mTOR) forms 2 distinct complexes, mTORC1 and mTORC2, and plays a central role in integrating biochemical signals for protein synthesis and cellular homeostasis, we explored its role in CTGF expression in adult feline CM. CM were stimulated with 10 μM phenylephrine (PE), 200 nM angiotensin (Ang), or 100 nM insulin for 24 hours. PE and Ang, but not insulin, caused an increase in CTGF mRNA expression with the highest expression observed with PE. Inhibition of mTOR with torin1 but not rapamycin significantly enhanced PE-stimulated CTGF expression. Furthermore, silencing of raptor and rictor using shRNA adenoviral vectors to suppress mTORC1 and mTORC2, respectively, or blocking phosphatidylinositol 3-kinase (PI3K) signaling with LY294002 (LY) or Akt signaling by dominant-negative Akt expression caused a substantial increase in PE-stimulated CTGF expression as measured by both mRNA and secreted protein levels. However, studies with dominant-negative delta isoform of protein kinase C demonstrate that delta isoform of protein kinase C is required for both agonist-induced CTGF expression and mTORC2/Akt-mediated CTGF suppression. Finally, PE-stimulated CTGF expression was accompanied with a corresponding increase in Smad3 phosphorylation and pretreatment of cells with SIS3, a Smad3 specific inhibitor, partially blocked the PE-stimulated CTGF expression. Therefore, a PI3K/mTOR/Akt axis plays a suppressive role on agonist-stimulated CTGF expression where the loss of this mechanism could be a contributing factor for the onset of cardiac fibrosis in the hypertrophying myocardium.
Collapse
Affiliation(s)
- Kamala Sundararaj
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Dorea L. Pleasant
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Phillip C. Moschella
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Kavin Panneerselvam
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Sundaravadivel Balasubramanian
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Dhandapani Kuppuswamy
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
- Corresponding author at: Gazes Cardiac Research Institute, Medical University of South Carolina, 114 Doughty Street, Charleston, South Carolina 29425-2221 Telephone: 843-876 5067; Fax: 843-876 5068;
| |
Collapse
|
20
|
Xu L, Brink M. mTOR, cardiomyocytes and inflammation in cardiac hypertrophy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1894-903. [PMID: 26775585 DOI: 10.1016/j.bbamcr.2016.01.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/30/2015] [Accepted: 01/07/2016] [Indexed: 02/07/2023]
Abstract
Mammalian target of rapamycin (mTOR) is an evolutionary conserved kinase that senses the nutrient and energy status of cells, the availability of growth factors, stress stimuli and other cellular and environmental cues. It responds by regulating a range of cellular processes related to metabolism and growth in accordance with the available resources and intracellular needs. mTOR has distinct functions depending on its assembly in the structurally distinct multiprotein complexes mTORC1 or mTORC2. Active mTORC1 enhances processes including glycolysis, protein, lipid and nucleotide biosynthesis, and it inhibits autophagy. Reported functions for mTORC2 after growth factor stimulation are very diverse, are tissue and cell-type specific, and include insulin-stimulated glucose transport and enhanced glycogen synthesis. In accordance with its cellular functions, mTOR has been demonstrated to regulate cardiac growth in response to pressure overload and is also known to regulate cells of the immune system. The present manuscript presents recently obtained insights into mechanisms whereby mTOR may change anabolic, catabolic and stress response pathways in cardiomocytes and discusses how mTOR may affect inflammatory cells in the heart during hemodynamic stress. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
Collapse
Affiliation(s)
- Lifen Xu
- Department of Biomedicine, University of Basel and University Hospital Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland
| | - Marijke Brink
- Department of Biomedicine, University of Basel and University Hospital Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland.
| |
Collapse
|
21
|
Zhang HM, Fu J, Hamilton R, Diaz V, Zhang Y. The mammalian target of rapamycin modulates the immunoproteasome system in the heart. J Mol Cell Cardiol 2015; 86:158-67. [PMID: 26239133 DOI: 10.1016/j.yjmcc.2015.07.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 07/11/2015] [Accepted: 07/28/2015] [Indexed: 12/16/2022]
Abstract
The mammalian target of rapamycin (mTOR) plays an important role in cardiac development and function. Inhibition of mTOR by rapamycin has been shown to attenuate pathological cardiac hypertrophy and improve the function of aging heart, accompanied by an inhibition of the cardiac proteasome activity. The current study aimed to determine the potential mechanism(s) by which mTOR inhibition modulates cardiac proteasome. Inhibition of mTOR by rapamycin was found to reduce primarily the immunoproteasome in both H9c2 cells in vitro and mouse heart in vivo, without significant effect on the constitutive proteasome and protein ubiquitination. Concurrent with the reduction of the immunoproteasome, rapamycin reduced two important inflammatory response pathways, the NF-κB and Stat3 signaling. In addition, rapamycin attenuated the induction of the immunoproteasome in H9c2 cells by inflammatory cytokines, including INFγ and TNFα, by suppressing NF-κB signaling. These data indicate that rapamycin indirectly modulated immunoproteasome through the suppression of inflammatory response pathways. Lastly, the role of the immunoproteasome during the development of cardiac hypertrophy was investigated. Administration of a specific inhibitor of the immunoproteasome ONX 0914 attenuated isoproterenol-induced cardiac hypertrophy, suggesting that the immunoproteasome may be involved in the development of cardiac hypertrophy and therefore could be a therapeutic target. In conclusion, rapamycin inhibits the immunoproteasome through its effect on the inflammatory signaling pathways and the immunoproteasome could be a potential therapeutic target for pathological cardiac hypertrophy.
Collapse
Affiliation(s)
- Hong-Mei Zhang
- Department of Clinical Oncology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
| | - Jianliang Fu
- Department of Neurology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Ryan Hamilton
- Barshop Institute, The University of Texas Health Science Center at San Antonio, TX 78249, United States
| | - Vivian Diaz
- Barshop Institute, The University of Texas Health Science Center at San Antonio, TX 78249, United States
| | - Yiqiang Zhang
- Barshop Institute, The University of Texas Health Science Center at San Antonio, TX 78249, United States; Department of Physiology, The University of Texas Health Science Center at San Antonio, TX 78249, United States
| |
Collapse
|
22
|
Yuan H, Wang X, Hill K, Chen J, Lemasters J, Yang SM, Sha SH. Autophagy attenuates noise-induced hearing loss by reducing oxidative stress. Antioxid Redox Signal 2015; 22:1308-24. [PMID: 25694169 PMCID: PMC4410759 DOI: 10.1089/ars.2014.6004] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AIMS Reactive oxygen species play a dual role in mediating both cell stress and defense pathways. Here, we used pharmacological manipulations and siRNA silencing to investigate the relationship between autophagy and oxidative stress under conditions of noise-induced temporary, permanent, and severe permanent auditory threshold shifts (temporary threshold shift [TTS], permanent threshold shift [PTS], and severe PTS [sPTS], respectively) in adult CBA/J mice. RESULTS Levels of oxidative stress markers (4-hydroxynonenal [4-HNE] and 3-nitrotyrosine [3-NT]) increased in outer hair cells (OHCs) in a noise-dose-dependent manner, whereas levels of the autophagy marker microtubule-associated protein light chain 3 B (LC3B) were sharply elevated after TTS but rose only slightly in response to PTS and were unaltered by sPTS noise. Furthermore, green fluorescent protein (GFP) intensity increased in GFP-LC3 mice after TTS-noise exposure. Treatment with rapamycin, an autophagy activator, significantly increased LC3B expression, while diminishing 4-HNE and 3-NT levels, reducing noise-induced hair cell loss, and, subsequently, noise-induced hearing loss (NIHL). In contrast, treatment with either the autophagy inhibitor 3-methyladenine (3MA) or LC3B siRNA reduced LC3B expression, increased 3-NT and 4-HNE levels, and exacerbated TTS to PTS. INNOVATION This study demonstrates a relationship between oxidative stress and autophagy in OHCs and reveals that autophagy is an intrinsic cellular process that protects against NIHL by attenuating oxidative stress. CONCLUSIONS The results suggest that the lower levels of oxidative stress incurred by TTS-noise exposure induce autophagy, which promotes OHC survival. However, excessive oxidative stress under sPTS-noise conditions overwhelms the beneficial potential of autophagy in OHCs and leads to OHC death and NIHL.
Collapse
Affiliation(s)
- Hu Yuan
- 1 Department of Pathology and Laboratory Medicine, Medical University of South Carolina , Charleston, South Carolina
| | | | | | | | | | | | | |
Collapse
|
23
|
Lopez RJ, Mosca B, Treves S, Maj M, Bergamelli L, Calderon JC, Bentzinger CF, Romanino K, Hall MN, Rüegg MA, Delbono O, Caputo C, Zorzato F. Raptor ablation in skeletal muscle decreases Cav1.1 expression and affects the function of the excitation-contraction coupling supramolecular complex. Biochem J 2015; 466:123-35. [PMID: 25431931 PMCID: PMC4843809 DOI: 10.1042/bj20140935] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The protein mammalian target of rapamycin (mTOR) is a serine/threonine kinase regulating a number of biochemical pathways controlling cell growth. mTOR exists in two complexes termed mTORC1 and mTORC2. Regulatory associated protein of mTOR (raptor) is associated with mTORC1 and is essential for its function. Ablation of raptor in skeletal muscle results in several phenotypic changes including decreased life expectancy, increased glycogen deposits and alterations of the twitch kinetics of slow fibres. In the present paper, we show that in muscle-specific raptor knockout (RamKO), the bulk of glycogen phosphorylase (GP) is mainly associated in its cAMP-non-stimulated form with sarcoplasmic reticulum (SR) membranes. In addition, 3[H]-ryanodine and 3[H]-PN200-110 equilibrium binding show a ryanodine to dihydropyridine receptors (DHPRs) ratio of 0.79 and 1.35 for wild-type (WT) and raptor KO skeletal muscle membranes respectively. Peak amplitude and time to peak of the global calcium transients evoked by supramaximal field stimulation were not different between WT and raptor KO. However, the increase in the voltage sensor-uncoupled RyRs leads to an increase of both frequency and mass of elementary calcium release events (ECRE) induced by hyper-osmotic shock in flexor digitorum brevis (FDB) fibres from raptor KO. The present study shows that the protein composition and function of the molecular machinery involved in skeletal muscle excitation-contraction (E-C) coupling is affected by mTORC1 signalling.
Collapse
Affiliation(s)
- Rubén J. Lopez
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Barbara Mosca
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Susan Treves
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Marcin Maj
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Leda Bergamelli
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Juan C. Calderon
- Laboratorio de Fisiología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020A Caracas, Venezuela
| | | | - Klaas Romanino
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | | | | | - Osvaldo Delbono
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, U.S.A
| | - Carlo Caputo
- Laboratorio de Fisiología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020A Caracas, Venezuela
| | - Francesco Zorzato
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| |
Collapse
|
24
|
Abstract
The protein kinase mammalian or mechanistic target of rapamycin (mTOR) is an atypical serine/threonine kinase that exerts its main cellular functions by interacting with specific adaptor proteins to form 2 different multiprotein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). mTORC1 regulates protein synthesis, cell growth and proliferation, autophagy, cell metabolism, and stress responses, whereas mTORC2 seems to regulate cell survival and polarity. The mTOR pathway plays a key regulatory function in cardiovascular physiology and pathology. However, the majority of information available about mTOR function in the cardiovascular system is related to the role of mTORC1 in the unstressed and stressed heart. mTORC1 is required for embryonic cardiovascular development and for postnatal maintenance of cardiac structure and function. In addition, mTORC1 is necessary for cardiac adaptation to pressure overload and development of compensatory hypertrophy. However, partial and selective pharmacological and genetic inhibition of mTORC1 was shown to extend life span in mammals, reduce pathological hypertrophy and heart failure caused by increased load or genetic cardiomyopathies, reduce myocardial damage after acute and chronic myocardial infarction, and reduce cardiac derangements caused by metabolic disorders. The optimal therapeutic strategy to target mTORC1 and increase cardioprotection is under intense investigation. This article reviews the information available regarding the effects exerted by mTOR signaling in cardiovascular physiology and pathological states.
Collapse
Affiliation(s)
- Sebastiano Sciarretta
- From the Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ (S.S., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S., M.V.); and Division of Cardiology, Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, University Sapienza, Rome, Italy (M.V.)
| | | | | |
Collapse
|
25
|
Bishu K, Ogut O, Kushwaha S, Mohammed SF, Ohtani T, Xu X, Brozovich FV, Redfield MM. Anti-remodeling effects of rapamycin in experimental heart failure: dose response and interaction with angiotensin receptor blockade. PLoS One 2013; 8:e81325. [PMID: 24312548 PMCID: PMC3849273 DOI: 10.1371/journal.pone.0081325] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/11/2013] [Indexed: 01/11/2023] Open
Abstract
While neurohumoral antagonists improve outcomes in heart failure (HF), cardiac remodeling and dysfunction progress and outcomes remain poor. Therapies superior or additive to standard HF therapy are needed. Pharmacologic mTOR inhibition by rapamycin attenuated adverse cardiac remodeling and dysfunction in experimental heart failure (HF). However, these studies used rapamycin doses that produced blood drug levels targeted for primary immunosuppression in human transplantation and therefore the immunosuppressive effects may limit clinical translation. Further, the relative or incremental effect of rapamycin combined with standard HF therapies targeting upstream regulators of cardiac remodeling (neurohumoral antagonists) has not been defined. Our objectives were to determine if anti-remodeling effects of rapamycin were preserved at lower doses and whether rapamycin effects were similar or additive to a standard HF therapy (angiotensin receptor blocker (losartan)). Experimental murine HF was produced by transverse aortic constriction (TAC). At three weeks post-TAC, male mice with established HF were treated with placebo, rapamycin at a dose producing immunosuppressive drug levels (target dose), low dose (50% target dose) rapamycin, losartan or rapamycin + losartan for six weeks. Cardiac structure and function (echocardiography, catheterization, pathology, hypertrophic and fibrotic gene expression profiles) were assessed. Downstream mTOR signaling pathways regulating protein synthesis (S6K1 and S6) and autophagy (LC3B-II) were characterized. TAC-HF mice displayed eccentric hypertrophy, systolic dysfunction and pulmonary congestion. These perturbations were attenuated to a similar degree by oral rapamycin doses achieving target (13.3±2.1 ng/dL) or low (6.7±2.5 ng/dL) blood levels. Rapamycin treatment decreased mTOR mediated regulators of protein synthesis and increased mTOR mediated regulators of autophagy. Losartan monotherapy did not attenuate remodeling, whereas Losartan added to rapamycin provided no incremental benefit over rapamycin alone. These data lend support to investigation of low dose rapamycin as a novel therapy in human HF.
Collapse
Affiliation(s)
- Kalkidan Bishu
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Ozgur Ogut
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sudhir Kushwaha
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Selma F. Mohammed
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Tomohito Ohtani
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Xiaolei Xu
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Frank V. Brozovich
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Margaret M. Redfield
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| |
Collapse
|
26
|
Völkers M, Konstandin MH, Doroudgar S, Toko H, Quijada P, Din S, Joyo A, Ornelas L, Samse K, Thuerauf DJ, Gude N, Glembotski CC, Sussman MA. Mechanistic target of rapamycin complex 2 protects the heart from ischemic damage. Circulation 2013; 128:2132-44. [PMID: 24008870 DOI: 10.1161/circulationaha.113.003638] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND The mechanistic target of rapamycin (mTOR) comprises 2 structurally distinct multiprotein complexes, mTOR complexes 1 and 2 (mTORC1 and mTORC2). Deregulation of mTOR signaling occurs during and contributes to the severity of myocardial damage from ischemic heart disease. However, the relative roles of mTORC1 versus mTORC2 in the pathogenesis of ischemic damage are unknown. METHODS AND RESULTS Combined pharmacological and molecular approaches were used to alter the balance of mTORC1 and mTORC2 signaling in cultured cardiac myocytes and in mouse hearts subjected to conditions that mimic ischemic heart disease. The importance of mTOR signaling in cardiac protection was demonstrated by pharmacological inhibition of both mTORC1 and mTORC2 with Torin1, which led to increased cardiomyocyte apoptosis and tissue damage after myocardial infarction. Predominant mTORC1 signaling mediated by suppression of mTORC2 with Rictor similarly increased cardiomyocyte apoptosis and tissue damage after myocardial infarction. In comparison, preferentially shifting toward mTORC2 signaling by inhibition of mTORC1 with PRAS40 led to decreased cardiomyocyte apoptosis and tissue damage after myocardial infarction. CONCLUSIONS These results suggest that selectively increasing mTORC2 while concurrently inhibiting mTORC1 signaling is a novel therapeutic approach for the treatment of ischemic heart disease.
Collapse
Affiliation(s)
- Mirko Völkers
- From SDSU Heart Institute, Department of Biology, San Diego State University, San Diego, CA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Moschella PC, McKillop J, Pleasant DL, Harston RK, Balasubramanian S, Kuppuswamy D. mTOR complex 2 mediates Akt phosphorylation that requires PKCε in adult cardiac muscle cells. Cell Signal 2013; 25:1904-12. [PMID: 23673367 PMCID: PMC3704180 DOI: 10.1016/j.cellsig.2013.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 05/06/2013] [Indexed: 01/28/2023]
Abstract
Our earlier work showed that mammalian target of rapamycin (mTOR) is essential to the development of various hypertrophic responses, including cardiomyocyte survival. mTOR forms two independent complexes, mTORC1 and mTORC2, by associating with common and distinct cellular proteins. Both complexes are sensitive to a pharmacological inhibitor, torin1, although only mTORC1 is inhibited by rapamycin. Since mTORC2 is known to mediate the activation of a prosurvival kinase, Akt, we analyzed whether mTORC2 directly mediates Akt activation or whether it requires the participation of another prosurvival kinase, PKCε (epsilon isoform of protein kinase-C). Our studies reveal that treatment of adult feline cardiomyocytes in vitro with insulin results in Akt phosphorylation at S473 for its activation which could be augmented with rapamycin but blocked by torin1. Silencing the expression of Rictor (rapamycin-insensitive companion of mTOR), an mTORC2 component, with a sh-RNA in cardiomyocytes lowers both insulin-stimulated Akt and PKCε phosphorylation. Furthermore, phosphorylation of PKCε and Akt at the critical S729 and S473 sites respectively was blocked by torin1 or Rictor knockdown but not by rapamycin, indicating that the phosphorylation at these specific sites occurs downstream of mTORC2. Additionally, expression of DN-PKCε significantly lowered the insulin-stimulated Akt S473 phosphorylation, indicating an upstream role for PKCε in the Akt activation. Biochemical analyses also revealed that PKCε was part of Rictor but not Raptor (a binding partner and component of mTORC1). Together, these studies demonstrate that mTORC2 mediates prosurvival signaling in adult cardiomyocytes where PKCε functions downstream of mTORC2 leading to Akt activation.
Collapse
Affiliation(s)
- Phillip C. Moschella
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - John McKillop
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Dorea L. Pleasant
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Rebecca K. Harston
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Sundaravadivel Balasubramanian
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| | - Dhandapani Kuppuswamy
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, SC 29425-2221
| |
Collapse
|
28
|
Chaveroux C, Eichner LJ, Dufour CR, Shatnawi A, Khoutorsky A, Bourque G, Sonenberg N, Giguère V. Molecular and genetic crosstalks between mTOR and ERRα are key determinants of rapamycin-induced nonalcoholic fatty liver. Cell Metab 2013; 17:586-98. [PMID: 23562079 DOI: 10.1016/j.cmet.2013.03.003] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/16/2012] [Accepted: 03/06/2013] [Indexed: 10/27/2022]
Abstract
mTOR and ERRα are key regulators of common metabolic processes, including lipid homeostasis. However, it is currently unknown whether these factors cooperate in the control of metabolism. ChIP-sequencing analyses of mouse liver reveal that mTOR occupies regulatory regions of genes on a genome-wide scale including enrichment at genes shared with ERRα that are involved in the TCA cycle and lipid biosynthesis. Genetic ablation of ERRα and rapamycin treatment, alone or in combination, alter the expression of these genes and induce the accumulation of TCA metabolites. As a consequence, both genetic and pharmacological inhibition of ERRα activity exacerbates hepatic hyperlipidemia observed in rapamycin-treated mice. We further show that mTOR regulates ERRα activity through ubiquitin-mediated degradation via transcriptional control of the ubiquitin-proteasome pathway. Our work expands the role of mTOR action in metabolism and highlights the existence of a potent mTOR/ERRα regulatory axis with significant clinical impact.
Collapse
Affiliation(s)
- Cédric Chaveroux
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Montréal, QC H3A 1A3, Canada
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Gürgen D, Kusch A, Klewitz R, Hoff U, Catar R, Hegner B, Kintscher U, Luft FC, Dragun D. Sex-specific mTOR signaling determines sexual dimorphism in myocardial adaptation in normotensive DOCA-salt model. Hypertension 2013; 61:730-6. [PMID: 23339165 DOI: 10.1161/hypertensionaha.111.00276] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The deoxycorticosterone acetate (DOCA)-salt mouse model exhibits adverse cardiac remodeling in male mice and cardiac protection in female mice, even when blood pressure is normalized. We hypothesized that intact mammalian target of rapamycin (mTOR) signaling is necessary for cardiac protection in females. We first tested sex differences and intracellular signaling after mTOR targeting with rapamycin in wild-type mice. Radio-telemetric blood pressure was maintained at normal for 6 weeks. Rapamycin significantly reduced left ventricular hypertrophy, preserved ejection fraction, inhibited fibrosis, and maintained capillary structure in male mice. Decreased mTORC1 and increased mTORC2 activity were detected in rapamycin-treated male mice compared with vehicle controls. In contrast, female mice developed dilative left ventricular hypertrophy, cardiac fibrosis, and capillary loss similar to DOCA-salt females lacking the estrogen receptor β (ERβ(-/-)) that we described earlier. Because rapamycin downregulated ERβ in female mice, we next studied ERβ(-/-) normotensive DOCA-salt females. Vehicle-treated wild-type females maintained their high constitutive mTORC1 and mTORC2 in response to DOCA-salt. In contrast to males, both mTORCs were decreased by rapamycin, in particular mTORC2 by 60%. ERβ(-/-) DOCA-salt females showed similar mTORC1 and mTORC2 response patterns. We suggest that ERβ-dependent regulation involves sex-specific use of mTOR signaling branches. Maintenance of both mTORC1 and mTORC2 signaling seems to be essential for adaptive cardiac remodeling in females and supports a rationale for sex-specific therapeutic strategies in left ventricular hypertrophy.
Collapse
Affiliation(s)
- Dennis Gürgen
- Department of Nephrology and Intensive Care Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Edelstein J, Rockwell P. Okadaic acid induces Akt hyperphosphorylation and an oxidative stress-mediated cell death in serum starved SK-N-SH human neuroblastoma cells that are augmented by rapamycin. Neurosci Lett 2012; 531:74-9. [PMID: 23127854 DOI: 10.1016/j.neulet.2012.10.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 08/06/2012] [Accepted: 10/22/2012] [Indexed: 02/05/2023]
Abstract
Using a neuronal model of serum starved SK-N-SH neuroblastoma cells, we showed previously that the phosphorylation of Akt and the mTOR substrates S6K and S6 through the vascular endothelial growth factor receptor VEGFR2 was enhanced by treatments with the phosphatase PP2A inhibitor okadaic acid (OA). These findings suggested that PP2A inhibition uncouples the regulation of Akt signaling by mTOR and affects cell survival. We therefore examined the effects of mTOR inhibition on Akt phosphorylation at sites threonine 308 (T308) and serine 473 (S473) and survival in OA treated cells. OA induced a loss in cell viability, the accumulation of hyperactivated Akt as monomeric and ubiquitinated forms and an increase in the total levels of ubiquitinated proteins. These events were exacerbated by treatments with an allosteric (rapamycin) but not an active-site inhibitor (PP242) of mTOR. Notably, rapamycin augmented the OA-induced hyperphosphorylation of Akt by suppressing a negative feedback loop of Akt activation through VEGFR2 and its downstream target phosphatidylinositol 3-kinase (PI3K). Treatments with the antioxidant N-acetlycysteine but not the pan caspase inhibitor Z-VAD-FMK promoted survival. Unlike reports that rapamycin promotes survival through increased Akt activation, these findings show that rapamycin-induced hyperphosphorylation of Akt fails to rescue our neuronal model from an oxidative stress-induced and caspase-independent cell death mediated by PP2A inhibition. Moreover, the exacerbation of OA-induced events by rapamycin suggests that mTOR and PP2A work in concert to regulate cell survival, activated Akt and the levels of ubiquitinated proteins.
Collapse
Affiliation(s)
- Jacob Edelstein
- Department of Biological Sciences, Hunter College of The City University of New York, 695 Park Avenue, New York, NY 10065, USA
| | | |
Collapse
|
31
|
Aoyagi T, Kusakari Y, Xiao CY, Inouye BT, Takahashi M, Scherrer-Crosbie M, Rosenzweig A, Hara K, Matsui T. Cardiac mTOR protects the heart against ischemia-reperfusion injury. Am J Physiol Heart Circ Physiol 2012; 303:H75-85. [PMID: 22561297 DOI: 10.1152/ajpheart.00241.2012] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cardiac mammalian target of rapamycin (mTOR) is necessary and sufficient to prevent cardiac dysfunction in pathological hypertrophy. However, the role of cardiac mTOR in heart failure after ischemic injury remains undefined. To address this question, we used transgenic (Tg) mice with cardiac-specific overexpression of mTOR (mTOR-Tg mice) to study ischemia-reperfusion (I/R) injury in two animal models: 1) in vivo I/R injury with transient coronary artery ligation and 2) ex vivo I/R injury in Langendorff-perfused hearts with transient global ischemia. At 28 days after I/R, mortality was lower in mTOR-Tg mice than littermate control mice [wild-type (WT) mice]. Echocardiography and MRI demonstrated that global cardiac function in mTOR-Tg mice was preserved, whereas WT mice exhibited significant cardiac dysfunction. Masson's trichrome staining showed that 28 days after I/R, the area of interstitial fibrosis was smaller in mTOR-Tg mice compared with WT mice, suggesting that adverse left ventricular remodeling is inhibited in mTOR-Tg mice. In the ex vivo I/R model, mTOR-Tg hearts demonstrated improved functional recovery compared with WT hearts. Perfusion with Evans blue after ex vivo I/R yielded less staining in mTOR-Tg hearts than WT hearts, indicating that mTOR overexpression inhibited necrosis during I/R injury. Expression of proinflammatory cytokines, including IL-6 and TNF-α, in mTOR-Tg hearts was lower than in WT hearts. Consistent with this, IL-6 in the effluent post-I/R injury was lower in mTOR-Tg hearts than in WT hearts. These findings suggest that cardiac mTOR overexpression in the heart is sufficient to provide substantial cardioprotection against I/R injury and suppress the inflammatory response.
Collapse
Affiliation(s)
- Toshinori Aoyagi
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, 96813, USA
| | | | | | | | | | | | | | | | | |
Collapse
|