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Aljaibeji H, Heydarpour M, Stanton AM, Williams JS, Pojoga LH, Romero JR, Williams GH. Role of Raptor Gene Variants in Hypertension: Influence on Blood Pressure Independent of Salt Intake in White Population. Hypertension 2024; 81:1167-1177. [PMID: 38497230 PMCID: PMC11023780 DOI: 10.1161/hypertensionaha.123.22273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/29/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND The mTOR (mechanistic target of rapamycin) is an essential regulator of fundamental biological processes. mTOR forms 2 distinct complexes, mTORC1 (mTOR complex 1) when it binds with RAPTOR (Regulatory-associated Protein of mTOR) and mTORC2 (mTOR complex 2) when it associates with RICTOR (Rapamycin-insesitive companion of mTOR). Due to the previous link between the mTOR pathway, aldosterone, and blood pressure (BP), we anticipated that variants in the mTOR complex might be associated with salt-sensitive BP. METHODS BP and other parameters were assessed after a one-week liberal Na+ (200 mmol/d) and a one-week restricted Na+ (10 mmol/d) diet in 608 White subjects from the Hypertensive Pathotype cohort, single-nucleotide variants in MTOR, RPTOR, and RICTOR genes were obtained for candidate genes analyses. RESULTS The analysis revealed a significant association between a single nucleotide variants within the RPTOR gene and BP. Individuals carrying the RPTOR rs9901846 homozygous risk allele (AA) and heterozygous risk allele (GA) exhibited a 5 mm Hg increase in systolic BP on a liberal diet compared with nonrisk allele individuals (GG), but only in women. This single nucleotide variants effect was more pronounced on the restricted diet and present in both sexes, with AA carriers having a 9 mm Hg increase and GA carriers having a 5 mm Hg increase in systolic BP compared with GG. Interestingly, there were no significant associations between MTOR or RICTOR gene variants and BP. CONCLUSIONS The RPTOR gene variation is associated with elevated BP in White participants, regardless of salt intake, specifically in females.
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Affiliation(s)
- Hayat Aljaibeji
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
| | - Mahyar Heydarpour
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
| | - Ana Maria Stanton
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
| | - Jonathan S Williams
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
| | - Luminita H Pojoga
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
| | - Jose R Romero
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
| | - Gordon H Williams
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA (H.A., M.H., A.M.S., J.S.W., L.H.P., J.R.R., G.H.W.)
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Zheng Z, Zhou H, Yang L, Zhang L, Guo M. Selective disruption of mTORC1 and mTORC2 in VTA astrocytes induces depression and anxiety-like behaviors in mice. Behav Brain Res 2024; 463:114888. [PMID: 38307148 DOI: 10.1016/j.bbr.2024.114888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/23/2024] [Accepted: 01/29/2024] [Indexed: 02/04/2024]
Abstract
Dysfunction of the mechanistic target of rapamycin (mTOR) signaling pathway is implicated in neuropsychiatric disorders including depression and anxiety. Most studies have been focusing on neurons, and the function of mTOR signaling pathway in astrocytes is less investigated. mTOR forms two distinct complexes, mTORC1 and mTORC2, with key scaffolding protein Raptor and Rictor, respectively. The ventral tegmental area (VTA), a vital component of the brain reward system, is enrolled in regulating both depression and anxiety. In the present study, we aimed to examine the regulation effect of VTA astrocytic mTOR signaling pathway on depression and anxiety. We specifically deleted Raptor or Rictor in VTA astrocytes in mice and performed a series of behavioral tests for depression and anxiety. Deletion of Raptor and Rictor both decreased the immobility time in the tail suspension test and the latency to eat in the novelty suppressed feeding test, and increased the horizontal activity and the movement time in locomotor activity. Deletion of Rictor decreased the number of total arm entries in the elevated plus-maze test and the vertical activity in locomotor activity. These data suggest that VTA astrocytic mTORC1 plays a role in regulating depression-related behaviors and mTORC2 is involved in both depression and anxiety-related behaviors. Our results indicate that VTA astrocytic mTOR signaling pathway might be new targets for the treatment of psychiatric disorders.
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Affiliation(s)
- Ziteng Zheng
- Department of Psychology, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China; Medical Research Center, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China
| | - Han Zhou
- Department of Psychology, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China; Medical Research Center, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China
| | - Lu Yang
- Department of Psychology, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China; Medical Research Center, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China
| | - Lanlan Zhang
- Department of Psychology, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China
| | - Ming Guo
- Department of Psychology, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China; Medical Research Center, Binzhou Medical University Hospital, the First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong 256603, China.
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Sztankovics D, Moldvai D, Petővári G, Dankó T, Szalai F, Miyaura R, Varga V, Nagy N, Papp G, Pápay J, Krencz I, Sebestyén A. mTOR hyperactivity and RICTOR amplification as targets for personalized treatments in malignancies. Pathol Oncol Res 2024; 30:1611643. [PMID: 38515456 PMCID: PMC10954904 DOI: 10.3389/pore.2024.1611643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/27/2024] [Indexed: 03/23/2024]
Abstract
The increasing knowledge of molecular alterations in malignancies, including mutations and regulatory failures in the mTOR (mechanistic target of rapamycin) signaling pathway, highlights the importance of mTOR hyperactivity as a validated target in common and rare malignancies. This review summarises recent findings on the characterization and prognostic role of mTOR kinase complexes (mTORC1 and mTORC2) activity regarding differences in their function, structure, regulatory mechanisms, and inhibitor sensitivity. We have recently identified new tumor types with RICTOR (rapamycin-insensitive companion of mTOR) amplification and associated mTORC2 hyperactivity as useful potential targets for developing targeted therapies in lung cancer and other newly described malignancies. The activity of mTOR complexes is recommended to be assessed and considered in cancers before mTOR inhibitor therapy, as current first-generation mTOR inhibitors (rapamycin and analogs) can be ineffective in the presence of mTORC2 hyperactivity. We have introduced and proposed a marker panel to determine tissue characteristics of mTOR activity in biopsy specimens, patient materials, and cell lines. Ongoing phase trials of new inhibitors and combination therapies are promising in advanced-stage patients selected by genetic alterations, molecular markers, and/or protein expression changes in the mTOR signaling pathway. Hopefully, the summarized results, our findings, and the suggested characterization of mTOR activity will support therapeutic decisions.
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Ali Y, Gomez-Sanchez CE, Plonczynski M, Naray-Fejes-Toth A, Fejes-Toth G, Gomez-Sanchez EP. mTOR Regulates Mineralocorticoid Receptor Transcriptional Activity by ULK1-Dependent and -Independent Mechanisms. Endocrinology 2024; 165:bqae015. [PMID: 38325289 PMCID: PMC10887451 DOI: 10.1210/endocr/bqae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/31/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
The mineralocorticoid receptor (MR) is a transcription factor for genes mediating diverse, cell-specific functions, including trophic effects as well as promoting fluid/electrolyte homeostasis. It was reported that in intercalated cells, phosphorylation of the MR at serine 843 (S843) by Unc-51-like kinase (ULK1) inhibits MR activation and that phosphorylation of ULK1 by mechanistic target of rapamycin (mTOR) inactivates ULK1, and thereby prevents MR inactivation. We extended these findings with studies in M1 mouse cortical collecting duct cells stably expressing the rat MR and a reporter gene. Pharmacological inhibition of ULK1 dose-dependently increased ligand-induced MR transactivation, while ULK1 activation had no effect. Pharmacological inhibition of mTOR and CRISPR/gRNA gene knockdown of rapamycin-sensitive adapter protein of mTOR (Raptor) or rapamycin-insensitive companion of mTOR (Rictor) decreased phosphorylated ULK1 and ligand-induced activation of the MR reporter gene, as well as transcription of endogenous MR-target genes. As predicted, ULK1 inhibition had no effect on aldosterone-mediated transcription in M1 cells with the mutated MR-S843A (alanine cannot be phosphorylated). In contrast, mTOR inhibition dose-dependently decreased transcription in the MR-S843A cells, though not as completely as in cells with the wild-type MR-S843. mTOR, Raptor, and Rictor coprecipitated with the MR and addition of aldosterone increased their phosphorylated, active state. These results suggest that mTOR significantly regulates MR activity in at least 2 ways: by suppressing MR inactivation by ULK1, and by a yet ill-defined mechanism that involves direct association with MR. They also provide new insights into the diverse functions of ULK1 and mTOR, 2 key enzymes that monitor the cell's energy status.
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Affiliation(s)
- Yusuf Ali
- Research Service, G. V. (Sonny) Montgomery VA Medical Center, Jackson, MS 39216, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Celso E Gomez-Sanchez
- Research Service, G. V. (Sonny) Montgomery VA Medical Center, Jackson, MS 39216, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Maria Plonczynski
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | | | - Geza Fejes-Toth
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03755, USA
| | - Elise P Gomez-Sanchez
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
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Wang C, Kang H, Yi Y, Ding Y, Wang F, Luo J, Ye M, Hong Y, Xia C, Yan J, Liu L, Liu J, Zhong Z, Zhang Z, Zhao Q, Chang Y. Rictor mediates p53 deactivation to facilitate the malignant transformation of hepatocytes and promote hepatocarcinogenesis. J Transl Med 2023; 21:919. [PMID: 38110956 PMCID: PMC10729423 DOI: 10.1186/s12967-023-04799-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023] Open
Abstract
BACKGROUND Mutations in TP53 gene is considered a main driver of hepatocellular carcinoma (HCC). While TP53 mutations are the leading cause of p53 dysfunction, their occurrence rates may drop to approximately 10% in cohorts without hepatitis B virus and aflatoxin exposure. This observation suggests that the deactivation of wild-type p53 (p53wt) may be a critical factor in the majority of HCC cases. However, the mechanism undermining p53wt activity in the liver remains unclear. METHODS Microarray analysis and luciferase assay were utilized to confirm target associations. Gain- and/or loss-of-function methods were employed to assess alterations in signaling pathways. Protein interactions were analyzed by molecular immunological methods and further visualized by confocal microscopy. Bioinformatic analysis was performed to analyze clinical significance. Tumor xenograft nude mice were used to validate the findings in vivo. RESULTS Our study highlights the oncogenic role of Rictor, a key component of the mammalian target of rapamycin complex 2 (mTORC2), in hepatocytes. Rictor exerts its oncogenic function by binding to p53wt and subsequently blocking p53wt activity based on p53 status, requiring the involvement of mTOR. Moreover, we observed a dynamic nucleocytoplasmic distribution pattern of Rictor, characterized by its translocation from the nucleus (in precancerous lesions) to the cytoplasm (in HCCs) during malignant transformation. Notably, Rictor is directly targeted by the liver-enriched microRNA miR-192, and the disruption of the miR-192-Rictor-p53-miR-192 signaling axis was consistently observed in both human and rat HCC models. Clinical analysis associated lower miR-192/higher Rictor with shorter overall survival and more advanced clinical stages (P < 0.05). In mice, xenograft tumors overexpressing miR-192 exhibited lower Rictor expression levels, leading to higher p53 activity, and these tumors displayed slower growth compared to untreated HCC cells. CONCLUSIONS Rictor dynamically shuttles between the nucleus and cytoplasm during HCC development. Its pivotal oncogenic role involves binding and inhibiting p53wt activity within the nucleus in early hepatocarcinogenesis. Targeting Rictor presents a promising strategy for HCC based on p53 status.
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Affiliation(s)
- Chun Wang
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Hui Kang
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Yun Yi
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Yang Ding
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Fan Wang
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Jie Luo
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Mingliang Ye
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Yinghui Hong
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Chao Xia
- Department of Geriatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China
- Institute of Liver Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Junwei Yan
- Institute of Liver Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Gastroenterology, Wuhan Central Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lan Liu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Jing Liu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China
| | - Zibiao Zhong
- Transplant Center of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Zhonglin Zhang
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Qiu Zhao
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China.
| | - Ying Chang
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
- Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Diseases, Wuhan, 430071, China.
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Deng YF, Wu ST, Peng HY, Tian L, Li YN, Yang Y, Meng M, Huang LL, Xiong PW, Li SY, Yang QL, Wang LL, Li XY, Li LP, Lu XL, Li XH, Wei YL, Xiao ZH, Yu JH, Deng YC. mTORC2 acts as a gatekeeper for mTORC1 deficiency-mediated impairments in ILC3 development. Acta Pharmacol Sin 2023; 44:2243-2252. [PMID: 37407703 PMCID: PMC10618277 DOI: 10.1038/s41401-023-01120-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/31/2023] [Indexed: 07/07/2023] Open
Abstract
Group 3 innate lymphoid cells (ILC3s) are mediators of intestinal immunity and barrier function. Recent studies have investigated the role of the mammalian target of rapamycin complex (mTOR) in ILC3s, whereas the mTORC1-related mechanisms and crosstalk between mTORC1 and mTORC2 involved in regulating ILC3 homeostasis remain unknown. In this study, we found that mTORC1 but not mTORC2 was critical in ILC3 development, IL-22 production, and ILC3-mediated intestinal homeostasis. Single-cell RNA sequencing revealed that mTORC1 deficiency led to disruption of ILC3 heterogeneity, showing an increase in differentiation into ILC1-like phenotypes. Mechanistically, mTORC1 deficiency decreased the expression of NFIL3, which is a critical transcription factor responsible for ILC3 development. The activities of both mTORC1 and mTORC2 were increased in wild-type ILC3s after activation by IL-23, whereas inhibition of mTORC1 by Raptor deletion or rapamycin treatment resulted in increased mTORC2 activity. Previous studies have demonstrated that S6K, the main downstream target of mTORC1, can directly phosphorylate Rictor to dampen mTORC2 activity. Our data found that inhibition of mTORC1 activity by rapamycin reduced Rictor phosphorylation in ILC3s. Reversing the increased mTORC2 activity via heterozygous or homozygous knockout of Rictor in Raptor-deleted ILC3s resulted in severe ILC3 loss and complete susceptibility to intestinal infection in mice with mTORC1 deficiency (100% mortality). Thus, mTORC1 acts as a rheostat of ILC3 heterogeneity, and mTORC2 protects ILC3s from severe loss of cells and immune activity against intestinal infection when mTORC1 activity is diminished.
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Affiliation(s)
- Ya-Fei Deng
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
- Department of Clinical Hematology, College of Pharmacy and Laboratory Medicine Science, Army Medical University, Chongqing, 400038, China
| | - Shu-Ting Wu
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Hong-Yan Peng
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Lei Tian
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA, USA
| | - Ya-Na Li
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Yao Yang
- Department of Clinical Hematology, College of Pharmacy and Laboratory Medicine Science, Army Medical University, Chongqing, 400038, China
| | - Meng Meng
- Department of Clinical Hematology, College of Pharmacy and Laboratory Medicine Science, Army Medical University, Chongqing, 400038, China
| | - Lan-Lan Huang
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Pei-Wen Xiong
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Song-Yang Li
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Qing-Lan Yang
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Li-Li Wang
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Xiao-Yao Li
- Department of Clinical Pharmacy, Weifang Traditional Chinese Hospital, Weifang, 261041, China
| | - Li-Ping Li
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Xiu-Lan Lu
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China
| | - Xiao-Hui Li
- Department of Clinical Hematology, College of Pharmacy and Laboratory Medicine Science, Army Medical University, Chongqing, 400038, China
| | - Yan-Ling Wei
- Department of Gastroenterology, Chongqing Key Laboratory of Digestive Malignancies, Daping Hospital, Army Medical University, Chongqing, 400042, China.
| | - Zheng-Hui Xiao
- Pediatrics Research Institute of Hunan Province and Hunan Provincial Key Laboratory of Children's Emergency Medicine, Hunan Children's Hospital, Changsha, 410007, China.
| | - Jian-Hua Yu
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA, USA.
| | - You-Cai Deng
- Department of Clinical Hematology, College of Pharmacy and Laboratory Medicine Science, Army Medical University, Chongqing, 400038, China.
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Shi F, Collins S. Regulation of mTOR Signaling: Emerging Role of Cyclic Nucleotide-Dependent Protein Kinases and Implications for Cardiometabolic Disease. Int J Mol Sci 2023; 24:11497. [PMID: 37511253 PMCID: PMC10380887 DOI: 10.3390/ijms241411497] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) kinase is a central regulator of cell growth and metabolism. It is the catalytic subunit of two distinct large protein complexes, mTOR complex 1 (mTORC1) and mTORC2. mTOR activity is subjected to tight regulation in response to external nutrition and growth factor stimulation. As an important mechanism of signaling transduction, the 'second messenger' cyclic nucleotides including cAMP and cGMP and their associated cyclic nucleotide-dependent kinases, including protein kinase A (PKA) and protein kinase G (PKG), play essential roles in mediating the intracellular action of a variety of hormones and neurotransmitters. They have also emerged as important regulators of mTOR signaling in various physiological and disease conditions. However, the mechanism by which cAMP and cGMP regulate mTOR activity is not completely understood. In this review, we will summarize the earlier work establishing the ability of cAMP to dampen mTORC1 activation in response to insulin and growth factors and then discuss our recent findings demonstrating the regulation of mTOR signaling by the PKA- and PKG-dependent signaling pathways. This signaling framework represents a new non-canonical regulation of mTOR activity that is independent of AKT and could be a novel mechanism underpinning the action of a variety of G protein-coupled receptors that are linked to the mTOR signaling network. We will further review the implications of these signaling events in the context of cardiometabolic disease, such as obesity, non-alcoholic fatty liver disease, and cardiac remodeling. The metabolic and cardiac phenotypes of mouse models with targeted deletion of Raptor and Rictor, the two essential components for mTORC1 and mTORC2, will be summarized and discussed.
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Affiliation(s)
- Fubiao Shi
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sheila Collins
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
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Liu Z, Huang Y, Jin X, Liu L, Gu H. PCB153 suppressed autophagy via PI3K/Akt/mTOR and RICTOR/Akt/mTOR signaling by the upregulation of microRNA-155 in rat primary chondrocytes. Toxicol Appl Pharmacol 2022; 449:116135. [PMID: 35732230 DOI: 10.1016/j.taap.2022.116135] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 06/07/2022] [Accepted: 06/15/2022] [Indexed: 02/04/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a typical type of persistent organic pollutant. PCB exposure is associated to the occurrence and development of osteoarthritis (OA); however, the involved mechanisms have yet to be elucidated. Here, we investigated the pro-osteoarthritic effect of 2, 2', 4, 4', 5, 5'-hexachlorobiphenyl (PCB153), and the involvement of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/ mammalian target of rapamycin (mTOR) and the RICTOR/Akt/mTOR signaling pathways. PCB153 of 20 and 30 μM increased the expression of MMP13 and decreased the expression of type II collagen, in a concentration-dependent manner. PCB153 treatment reduced the expression of Beclin 1 and LC3B, but increased the expression of p62 by upregulating miR-155 levels. PCB153 treatment activated the PI3K/Akt/mTOR signaling pathway by upregulating miR-155 levels. RICTOR was involved in activating the Akt/mTOR signaling pathway, and was also regulated by miR-155. In conclusion, PCB153 could promote the degradation of the extracellular matrix of chondrocytes by upregulating miR-155 via a mechanism related to the activation of the PI3K/Akt/mTOR and RICTOR/Akt/mTOR signaling pathway, which suppressed autophagy and facilitated the development of OA. MiR-155 may represent potential therapeutic targets to alleviate the development of OA.
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Affiliation(s)
- Ziyu Liu
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, 110122, China
| | - Yue Huang
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, 110122, China
| | - Xin Jin
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, 110122, China
| | - Li Liu
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, 110122, China
| | - Hailun Gu
- Department of Orthopedics, Shengjing Hospital, China Medical University, 110004, China.
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Yu Z, Chen J, Takagi E, Wang F, Saha B, Liu X, Joubert LM, Gleason CE, Jin M, Li C, Nowotny C, Agard D, Cheng Y, Pearce D. Interactions between mTORC2 core subunits Rictor and mSin1 dictate selective and context-dependent phosphorylation of substrate kinases SGK1 and Akt. J Biol Chem 2022; 298:102288. [PMID: 35926713 PMCID: PMC9440446 DOI: 10.1016/j.jbc.2022.102288] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 12/02/2022] Open
Abstract
Mechanistic target of rapamycin complex 2 (mTORC2) is a multi-subunit kinase complex, central to multiple essential signaling pathways. Two core subunits, Rictor and mSin1, distinguish it from the related mTORC1 and support context-dependent phosphorylation of its substrates. mTORC2 structures have been determined previously; however, important questions remain, particularly regarding the structural determinants mediating substrate specificity and context-dependent activity. Here, we used cryo-EM to obtain high-resolution structures of the human mTORC2 apo-complex in the presence of substrates Akt and SGK1. Using functional assays, we then tested predictions suggested by substrate-induced structural changes in mTORC2. For the first time, we visualized in the apo-state the side chain interactions between Rictor and mTOR that sterically occlude recruitment of mTORC1 substrates and confer resistance to the mTORC1 inhibitor rapamycin. Also in the apo-state, we observed that mSin1 formed extensive contacts with Rictor via a pair of short α-helices nestled between two Rictor helical repeat clusters, as well as by an extended strand that makes multiple weak contacts with Rictor helical cluster 1. In co-complex structures, we found that SGK1, but not Akt, markedly altered the conformation of the mSin1 N-terminal extended strand, disrupting multiple weak interactions while inducing a large rotation of mSin1 residue Arg-83, which then interacts with a patch of negatively charged residues within Rictor. Finally, we demonstrate mutation of Arg-83 to Ala selectively disrupts mTORC2-dependent phosphorylation of SGK1, but not of Akt, supporting context-dependent substrate selection. These findings provide new structural and functional insights into mTORC2 specificity and context-dependent activity.
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Affiliation(s)
- Zanlin Yu
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Junliang Chen
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Enzo Takagi
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Feng Wang
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Bidisha Saha
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Xi Liu
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Lydia-Marie Joubert
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA
| | - Catherine E Gleason
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Mingliang Jin
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Chengmin Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Carlos Nowotny
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - David Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA; Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA
| | - David Pearce
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA.
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10
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Jangani M, Vuononvirta J, Yamani L, Ward E, Capasso M, Nadkarni S, Balkwill F, Marelli-Berg F. Loss of mTORC2-induced metabolic reprogramming in monocytes uncouples migration and maturation from production of proinflammatory mediators. J Leukoc Biol 2022; 111:967-980. [PMID: 34585416 DOI: 10.1002/jlb.1a0920-588r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Monocyte migration to the sites of inflammation and maturation into macrophages are key steps for their immune effector function. Here, we show that mechanistic target of rapamycin complex 2 (mTORC2)-dependent Akt activation is instrumental for metabolic reprogramming at the early stages of macrophage-mediated immunity. Despite an increased production of proinflammatory mediators, monocytes lacking expression of the mTORC2 component Rictor fail to efficiently migrate to inflammatory sites and fully mature into macrophages, resulting in reduced inflammatory responses in vivo. The mTORC2-dependent phosphorylation of Akt is instrumental for the enhancement of glycolysis and mitochondrial respiration, required to sustain monocyte maturation and motility. These observations are discussed in the context of therapeutic strategies aimed at selective inhibition of mTORC2 activity.
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Affiliation(s)
- Maryam Jangani
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Juho Vuononvirta
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Lamya Yamani
- Barts Cancer Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Eleanor Ward
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Melania Capasso
- Barts Cancer Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
- German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Bonn, Germany
| | - Suchita Nadkarni
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Frances Balkwill
- Barts Cancer Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Federica Marelli-Berg
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
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11
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Mavropalias G, Wu YF, Boppart MD, Blazevich AJ, Nosaka K. Increases in Integrin-ILK-RICTOR-Akt Proteins, Muscle Mass, and Strength after Eccentric Cycling Training. Med Sci Sports Exerc 2022; 54:89-97. [PMID: 34468415 PMCID: PMC8921492 DOI: 10.1249/mss.0000000000002778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE Recently, it has been suggested that a cellular pathway composed of integrin, integrin-linked kinase (ILK), rapamycin-insensitive companion of mTOR (RICTOR), and Akt may facilitate long-term structural and functional adaptations associated with exercise, independent of the mTORC1 pathway. Therefore, we examined changes in integrin-ILK-RICTOR-Akt protein in vastus lateralis (VL) before and after 8 wk of eccentric cycling training (ECC), which was expected to increase muscle function and VL cross-sectional area (CSA). METHODS Eleven men (23 ± 4 yr) completed 24 sessions of ECC with progressive increases in intensity and duration, resulting in a twofold increase in work from the first three (75.4 ± 14.1 kJ) to the last three sessions (150.7 ± 28.4 kJ). Outcome measures included lower limb lean mass, VL CSA, static strength, and peak and average cycling power output. These measures and VL samples were taken before and 4-5 d after the last training session. RESULTS Significant (P < 0.05) increases in integrin-β1 (1.64-fold) and RICTOR (2.99-fold) protein as well as the phosphorylated-to-total ILK ratio (1.70-fold) were found, but integrin-α7 and Akt did not change. Increases in lower limb, thigh, and trunk lean mass (2.8%-5.3%, P < 0.05) and CSA (13.3% ± 9.0%, P < 0.001) were observed. Static strength (18.1% ± 10.8%) and both peak (8.6% ± 10.5%) and average power output (7.4% ± 8.3%) also increased (P < 0.05). However, no significant correlations were found between the magnitude of increases in protein and the magnitude of increases in CSA, static strength, or power output. CONCLUSIONS In addition to increased muscle mass, strength, and power, we demonstrate that ECC increases integrin-β1 and RICTOR total protein and p-ILK/t-ILK, which may play a role in protection against muscle damage as well as anabolic signaling to induce muscle adaptations.
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Affiliation(s)
- Georgios Mavropalias
- Exercise Medicine Research Institute, Edith Cowan University, Australia
- School of Medical and Health Sciences, Edith Cowan University, Australia
| | - Yu-Fu Wu
- Department of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, IL
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL
| | - Marni D. Boppart
- Department of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, IL
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL
| | | | - Kazunori Nosaka
- Exercise Medicine Research Institute, Edith Cowan University, Australia
- School of Medical and Health Sciences, Edith Cowan University, Australia
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12
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Imasawa T, Claverol S, Lacombe D, Amoedo ND, Rossignol R. Proteomic Study of Low-Birth-Weight Nephropathy in Rats. Int J Mol Sci 2021; 22:10294. [PMID: 34638634 PMCID: PMC8508940 DOI: 10.3390/ijms221910294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 02/06/2023] Open
Abstract
The hyperfiltration theory has been used to explain the mechanism of low birth weight (LBW)-related nephropathy. However, the molecular changes in the kidney proteome have not been defined in this disease, and early biomarkers are lacking. We investigated the molecular pathogenesis of LBW rats obtained by intraperitoneal injection of dexamethasone into pregnant animals. Normal-birth-weight (NBW) rats were used as controls. When the rats were four weeks old, the left kidneys were removed and used for comprehensive label-free proteomic studies. Following uninephrectomy, all rats were fed a high-salt diet until 9 weeks of age. Differences in the molecular composition of the kidney cortex were observed at the early step of LBW nephropathy pathogenesis. Untargeted quantitative proteomics showed that proteins involved in energy metabolism, such as oxidative phosphorylation (OXPHOS), the TCA cycle, and glycolysis, were specifically downregulated in the kidneys of LBW rats at four weeks. No pathological changes were detected at this early stage. Pathway analysis identified NEFL2 (NRF2) and RICTOR as potential upstream regulators. The search for biomarkers identified components of the mitochondrial respiratory chain, namely, ubiquinol-cytochrome c reductase complex subunits (UQCR7/11) and ATP5I/L, two components of mitochondrial F1FO-ATP synthase. These findings were further validated by immunohistology. At later stages of the disease process, the right kidneys revealed an increased frequency of focal segmental glomerulosclerosis lesions, interstitial fibrosis and tubular atrophy. Our findings revealed proteome changes in LBW rat kidneys and revealed a strong downregulation of specific mitochondrial respiratory chain proteins, such as UQCR7.
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Affiliation(s)
- Toshiyuki Imasawa
- Kidney Center, National Hospital Organization Chiba-Higashi National Hospital, Chiba 260-8712, Japan
- Rare Diseases, Genetics and Metabolism, University of Bordeaux, INSERM U1211, 33000 Bordeaux, France;
- Department of Biology and Medical Sciences, University of Bordeaux, 33000 Bordeaux, France;
| | - Stéphane Claverol
- Department of Biology and Medical Sciences, University of Bordeaux, 33000 Bordeaux, France;
- Functional Genomics Center, Proteomics Department, University of Bordeaux, 33000 Bordeaux, France
| | - Didier Lacombe
- Rare Diseases, Genetics and Metabolism, University of Bordeaux, INSERM U1211, 33000 Bordeaux, France;
- Department of Biology and Medical Sciences, University of Bordeaux, 33000 Bordeaux, France;
| | | | - Rodrigue Rossignol
- Rare Diseases, Genetics and Metabolism, University of Bordeaux, INSERM U1211, 33000 Bordeaux, France;
- Department of Biology and Medical Sciences, University of Bordeaux, 33000 Bordeaux, France;
- CELLOMET, CHU Pellegrin, 33300 Bordeaux, France;
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13
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Makkos A, Ágg B, Varga ZV, Giricz Z, Gyöngyösi M, Lukovic D, Schulz R, Barteková M, Görbe A, Ferdinandy P. Molecular Network Approach Reveals Rictor as a Central Target of Cardiac ProtectomiRs. Int J Mol Sci 2021; 22:ijms22179539. [PMID: 34502448 PMCID: PMC8430799 DOI: 10.3390/ijms22179539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/23/2021] [Accepted: 08/30/2021] [Indexed: 12/12/2022] Open
Abstract
Cardioprotective medications are still unmet clinical needs. We have previously identified several cardioprotective microRNAs (termed ProtectomiRs), the mRNA targets of which may reveal new drug targets for cardioprotection. Here we aimed to identify key molecular targets of ProtectomiRs and confirm their association with cardioprotection in a translational pig model of acute myocardial infarction (AMI). By using a network theoretical approach, we identified 882 potential target genes of 18 previously identified protectomiRs. The Rictor gene was the most central and it was ranked first in the protectomiR-target mRNA molecular network with the highest node degree of 5. Therefore, Rictor and its targeting microRNAs were further validated in heart samples obtained from a translational pig model of AMI and cardioprotection induced by pre- or postconditioning. Three out of five Rictor-targeting pig homologue of rat ProtectomiRs showed significant upregulation in postconditioned but not in preconditioned pig hearts. Rictor was downregulated at the mRNA and protein level in ischemic postconditioning but not in ischemic preconditioning. This is the first demonstration that Rictor is the central molecular target of ProtectomiRs and that decreased Rictor expression may regulate ischemic postconditioning-, but not preconditioning-induced acute cardioprotection. We conclude that Rictor is a potential novel drug target for acute cardioprotection.
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Affiliation(s)
- András Makkos
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; (A.M.); (B.Á.); (Z.V.V.); (Z.G.); (P.F.)
- MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary
| | - Bence Ágg
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; (A.M.); (B.Á.); (Z.V.V.); (Z.G.); (P.F.)
- MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary
- Pharmahungary Group, 6722 Szeged, Hungary
| | - Zoltán V. Varga
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; (A.M.); (B.Á.); (Z.V.V.); (Z.G.); (P.F.)
- HCEMM-SU Cardiometabolic Immunology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary
| | - Zoltán Giricz
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; (A.M.); (B.Á.); (Z.V.V.); (Z.G.); (P.F.)
| | - Mariann Gyöngyösi
- Division of Cardiology, Medical University of Vienna, 1090 Vienna, Austria; (M.G.); (D.L.)
| | - Dominika Lukovic
- Division of Cardiology, Medical University of Vienna, 1090 Vienna, Austria; (M.G.); (D.L.)
| | - Rainer Schulz
- Institute of Physiology, Justus Liebig University Giessen, 35392 Giessen, Germany;
| | - Monika Barteková
- Institute for Heart Research, Centre of Experimental Medicine, Slovak Academy of Sciences, Dúbravská cesta 9, 84104 Bratislava, Slovakia;
- Institute of Physiology, Comenius University in Bratislava, 81108 Bratislava, Slovakia
| | - Anikó Görbe
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; (A.M.); (B.Á.); (Z.V.V.); (Z.G.); (P.F.)
- MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary
- Pharmahungary Group, 6722 Szeged, Hungary
- Correspondence:
| | - Péter Ferdinandy
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; (A.M.); (B.Á.); (Z.V.V.); (Z.G.); (P.F.)
- MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary
- Pharmahungary Group, 6722 Szeged, Hungary
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14
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Ramaiah MJ, Kumar KR. mTOR-Rictor-EGFR axis in oncogenesis and diagnosis of glioblastoma multiforme. Mol Biol Rep 2021; 48:4813-4835. [PMID: 34132942 DOI: 10.1007/s11033-021-06462-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 06/01/2021] [Indexed: 12/12/2022]
Abstract
Glioblastoma multiforme (GBM) is one of the aggressive brain cancers with patients having less survival period upto 12-15 months. Mammalian target of rapamycin (mTOR) is a serine/threonine kinase, belongs to the phosphatidylinositol 3-kinases (PI3K) pathway and is involved in various cellular processes of cancer cells. Cancer metabolism is regulated by mTOR and its components. mTOR forms two complexes as mTORC1 and mTORC2. Studies have identified the key component of the mTORC2 complex, Rapamycin-insensitive companion of mammalian target of rapamycin (Rictor) plays a prominent role in the regulation of cancer cell proliferation and metabolism. Apart, growth factor receptor signaling such as epidermal growth factor signaling mediated by epidermal growth factor receptor (EGFR) regulates cancer-related processes. In EGFR signaling various other signaling cascades such as phosphatidyl-inositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR pathway) and Ras/Raf/mitogen-activated protein kinase/ERK kinase (MEK)/extracellular-signal-regulated kinase (ERK) -dependent signaling cross-talk each other. From various studies about GBM, it is very well established that Rictor and EGFR mediated signaling pathways majorly playing a pivotal role in chemoresistance and tumor aggressiveness. Recent studies have shown that non-coding RNAs such as microRNAs (miRs) and long non-coding RNAs (lncRNAs) regulate the EGFR and Rictor and sensitize the cells towards chemotherapeutic agents. Thus, understanding of microRNA mediated regulation of EGFR and Rictor will help in cancer prevention and management as well as a future therapy.
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Affiliation(s)
- M Janaki Ramaiah
- Functional Genomics and Disease Biology Laboratory, School of Chemical and Biotechnology (SCBT), SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613401, Tamil Nadu, India.
- School of Chemical and Biotechnology (SCBT), SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613401, Tamil Nadu, India.
| | - K Rohil Kumar
- Functional Genomics and Disease Biology Laboratory, School of Chemical and Biotechnology (SCBT), SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613401, Tamil Nadu, India
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15
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Castro-Martinez F, Candelario-Martinez A, Encarnacion-Garcia MR, Piedra-Quintero Z, Bonilla-Moreno R, Betanzos A, Perez-Orozco R, Hernandez-Cueto MA, Muñoz-Medina JE, Patiño-Lopez G, Schnoor M, Villegas-Sepulveda N, Nava P. Rictor/Mammalian Target of Rapamycin Complex 2 Signaling Protects Colonocytes from Apoptosis and Prevents Epithelial Barrier Breakdown. Am J Pathol 2021; 191:1537-1549. [PMID: 34139193 DOI: 10.1016/j.ajpath.2021.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/18/2021] [Accepted: 06/07/2021] [Indexed: 11/29/2022]
Abstract
Epithelial barrier impairment is a hallmark of several pathologic processes in the gut, including inflammatory bowel diseases. Several intracellular signals prevent apoptosis in intestinal epithelial cells. Herein, we show that in colonocytes, rictor/mammalian target of rapamycin complex 2 (mTORC2) signaling is a prosurvival stimulus. Mechanistically, mTORC2 activates Akt, which, in turn, inhibits apoptosis by phosphorylating B-cell lymphoma 2 (BCL2) associated agonist of cell death (Bad) and preventing caspase-3 activation. Nevertheless, during inflammation, rictor/mTORC2 signaling declines and Akt activity is reduced. Consequently, active caspase-3 increases in surface colonocytes undergoing apoptosis/anoikis and causes epithelial barrier breakdown. Likewise, Rictor ablation in intestinal epithelial cells interrupts mTORC2/Akt signaling and increases apoptosis/anoikis of surface colonocytes without affecting the crypt architecture. The increase in epithelial permeability induced by Rictor ablation produces a mild inflammatory response in the colonic mucosa, but minimally affects the development/establishment of colitis. The data identify a previously unknown mechanism by which rictor/mTORC2 signaling regulates apoptosis/anoikis in intestinal epithelial cells during colitis and clarify its role in the maintenance of the intestinal epithelial barrier.
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Affiliation(s)
- Felipe Castro-Martinez
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Aurora Candelario-Martinez
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Maria R Encarnacion-Garcia
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Zayda Piedra-Quintero
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Raul Bonilla-Moreno
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Abigail Betanzos
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Rocio Perez-Orozco
- Medicine Program for the Teaching and Development of Scientific Research in Iztacala (MEDICI Program), Faculty of Advanced Studies Iztacala, National Autonomous University of Mexico, Mexico-City, Mexico
| | - Maria A Hernandez-Cueto
- Central Laboratory of Epidemiology, Mexican. Institute of Social Security, Mexico-City, Mexico
| | - Jose E Muñoz-Medina
- Central Laboratory of Epidemiology, Mexican. Institute of Social Security, Mexico-City, Mexico
| | - Genaro Patiño-Lopez
- Laboratory of Research in Immunology and Proteomics, Federico Gómez Children's Hospital of Mexico, Mexico-City, Mexico
| | - Michael Schnoor
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Nicolas Villegas-Sepulveda
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico.
| | - Porfirio Nava
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico.
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16
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Liang Z, Zhang Q, Dong X, Zhang Z, Wang H, Zhang J, Zhao Y. mTORC2 negatively controls the maturation process of medullary thymic epithelial cells by inhibiting the LTβR/RANK-NF-κB axis. J Cell Physiol 2021; 236:4725-4737. [PMID: 33269476 DOI: 10.1002/jcp.30192] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/06/2020] [Accepted: 11/20/2020] [Indexed: 01/01/2023]
Abstract
The differentiation of mature medullary thymic epithelial cells (mTECs) is critical for the induction of central immune tolerance. Although the critical effect of mechanistic target of rapamycin complex 1 (mTORC1) in shaping mTEC differentiation has been studied, the regulatory role of mTORC2 in the differentiation and maturation of mTECs is poorly understood. We herein reported that TEC-specific ablation of a rapamycin-insensitive companion of mTOR (RICTOR), a key component of mTORC2, significantly decreased the thymus size and weight, the total cell number of TECs, and the cell number of mTECs with a smaller degree of reduced cortical thymic epithelial cells. Interestingly, RICTOR deficiency significantly accelerated the mTEC maturation process, as indicated by the increased ratios of mature mTECs (MHCIIhi , CD80+ , and Aire+ ) to immature mTECs (MHCIIlo , CD80- , and Aire- ) in Rictor-deficient mice. The RNA-sequencing assays showed that the upregulated nuclear factor-κB (NF-κB) signaling pathway in Rictor-deficient mTECs was one of the obviously altered pathways compared with wild-type mTECs. Our studies further showed that Rictor-deficient mTECs exhibited upregulated expression of receptor activator of NF-κB (RANK) and lymphotoxin β receptor (LTβR), as well as increased activity of canonical and noncanonical NF-κB signaling pathways as determined by ImageStream and Simple Western. Finally, our results showed that inhibition of NF-κB signaling pathways could partially reverse the accelerated maturation of mTECs in Rictor conditional KO mice. Thus, mTORC2 negatively controls the kinetics of the mTEC maturation process by inhibiting the LTβR/RANK-NF-κB signal axis.
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Affiliation(s)
- Zhanfeng Liang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qian Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xue Dong
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhaoqi Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hongxia Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Jiayu Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yong Zhao
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
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17
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Ding Y, Lv C, Zhou Y, Zhang H, Zhao L, Xu Y, Fan X. Vimentin loss promotes cancer proliferation through up-regulating Rictor/AKT/β-catenin signaling pathway. Exp Cell Res 2021; 405:112666. [PMID: 34052237 DOI: 10.1016/j.yexcr.2021.112666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/09/2021] [Accepted: 05/22/2021] [Indexed: 11/18/2022]
Abstract
Vimentin protein is one of the main cytoskeleton and plays an important role in cell motility and metastasis. Nowadays, vimentin is widely studied as an epithelial-mesenchymal transition (EMT) marker of cancer cells while its involvement in cancer proliferation is poorly understood. In this study, we investigated the participation of vimentin in regulating cancer proliferation by silencing VIM gene in four cancer cell lines. Our results demonstrated that vimentin loss significantly induced cancer cell proliferation both in vitro and in vivo, which has not been reported so far. Mechanistically, knockdown of vimentin expression activated AKT phosphorylation and its downstream β-catenin signaling. Nuclear translocation and transcriptional activity of β-catenin was enhanced after silencing vimentin expression. Furthermore, vimentin loss could prevent Rictor from autophagy-dependent degradation via reducing AMPK-mediated autophagy signaling. AICAR, an AMPK activator, down-regulated Rictor and p-AKT levels while vimentin knockdown could rescue the effects. In vivo, it was also found that Ki67 expression and p-AKT/β-catenin signaling pathway were obviously up-regulated in the tumor tissues in which vimentin was silenced compared to control groups. Taken together, these data showed the novel function of vimentin in regulating cancer proliferation via Rictor/AKT/β-catenin signaling pathway, which suggested that it need more careful consideration before inhibiting metastatic cancers through targeting vimentin.
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Affiliation(s)
- Youxiang Ding
- Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Conggai Lv
- The Second Hospital of Shi JiaZhuang, Shi Jiazhuang, 050000, China
| | - You Zhou
- School of Basic Medicine and Clinical Pharmacology, China Pharmaceutical University, Nanjing, 211100, China
| | - Heng Zhang
- School of Basic Medicine and Clinical Pharmacology, China Pharmaceutical University, Nanjing, 211100, China
| | - Li Zhao
- School of Basic Medicine and Clinical Pharmacology, China Pharmaceutical University, Nanjing, 211100, China
| | - Yuting Xu
- School of Basic Medicine and Clinical Pharmacology, China Pharmaceutical University, Nanjing, 211100, China
| | - Xiangshan Fan
- Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, 210008, China.
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18
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Lv Z, Yue Z, Shao Y, Li C, Zhao X, Guo M. mTORC2/Rictor is essential for coelomocyte endocytosis in Apostichopus japonicus. Dev Comp Immunol 2021; 118:104000. [PMID: 33444645 DOI: 10.1016/j.dci.2021.104000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 06/12/2023]
Abstract
Endocytosis plays an important role in the immune defence systems of invertebrates through the interaction between the mechanical target of rapamycin complex 2 (mTORC2) and the AGC kinase family. Rictor is the most important unique subunit protein of mTORC2 and is thought to regulate almost all functions of mTORC2, including endocytosis. In the present study, a novel invertebrate Rictor homologue was identified from Apostichopus japonicus (designated as AjRictor) via the rapid amplification of cDNA ends (RACE). Spatial expression analysis indicated that AjRictor is ubiquitously expressed in all the examined tissues and has the highest transcript level in coelomocytes. Vibrio splendidus challenge in vivo and lipopolysaccharide (LPS) exposure in vitro could remarkably up-regulate the messenger RNA (mRNA) expression of AjRictor compared with the control group. AjRictor knockdown by 0.49- and 0.69-fold resulted in the significant decrease in endocytosis rate by 0.53- (P < 0.01) and 0.59-fold (P < 0.01) in vivo and in vitro compared with the control group, respectively. Similarly, the treatment of coelomocytes with rapamycin for 24 h and the destruction of the assembly of mTORC2 markedly decreased the endocytosis rate of the coelomocytes by 35.92% (P < 0.05). We detected the expression levels of endocytosis-related molecular markers after AjRictor knockdown and rapamycin treatment to further study the molecular mechanism between mTORC2 and endocytosis. Our results showed that AGC kinase family members (PKCα and Pan1) and the phosphorylation level of AktS473 were remarkably decreased after reducing mTORC2 activity; thus, mTORC2/Rictor plays a key role in the immune regulation of endocytosis in coelomocytes. Our current study indicates that mTORC2/Rictor is involved in the coelomocyte endocytosis of sea cucumber and plays an essential regulation role in defending pathogen invasion.
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Affiliation(s)
- Zhimeng Lv
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Zongxu Yue
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Yina Shao
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China.
| | - Chenghua Li
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China.
| | - Xuelin Zhao
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Ming Guo
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
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19
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Zhao Y, Schoeps B, Yao D, Zhang Z, Schuck K, Tissen V, Jäger C, Schlitter AM, van der Kammen R, Ludwig C, D'Haese JG, Raulefs S, Maeritz N, Shen S, Zou X, Krüger A, Kleeff J, Michalski CW, Friess H, Innocenti M, Kong B. mTORC1 and mTORC2 Converge on the Arp2/3 Complex to Promote Kras G12D-Induced Acinar-to-Ductal Metaplasia and Early Pancreatic Carcinogenesis. Gastroenterology 2021; 160:1755-1770.e17. [PMID: 33388318 DOI: 10.1053/j.gastro.2020.12.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 12/04/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Oncogenic KrasG12D induces neoplastic transformation of pancreatic acinar cells through acinar-to-ductal metaplasia (ADM), an actin-based morphogenetic process, and drives pancreatic ductal adenocarcinoma (PDAC). mTOR (mechanistic target of rapamycin kinase) complex 1 (mTORC1) and 2 (mTORC2) contain Rptor and Rictor, respectively, and are activated downstream of KrasG12D, thereby contributing to PDAC. Yet, whether and how mTORC1 and mTORC2 impact on ADM and the identity of the actin nucleator(s) mediating such actin rearrangements remain unknown. METHODS A mouse model of inflammation-accelerated KrasG12D-driven early pancreatic carcinogenesis was used. Rptor, Rictor, and Arpc4 (actin-related protein 2/3 complex subunit 4) were conditionally ablated in acinar cells to deactivate the function of mTORC1, mTORC2 and the actin-related protein (Arp) 2/3 complex, respectively. RESULTS We found that mTORC1 and mTORC2 are markedly activated in human and mouse ADM lesions, and cooperate to promote KrasG12D-driven ADM in mice and in vitro. They use the Arp2/3 complex as a common downstream effector to induce the remodeling the actin cytoskeleton leading to ADM. In particular, mTORC1 regulates the translation of Rac1 (Rac family small GTPase 1) and the Arp2/3-complex subunit Arp3, whereas mTORC2 activates the Arp2/3 complex by promoting Akt/Rac1 signaling. Consistently, genetic ablation of the Arp2/3 complex prevents KrasG12D-driven ADM in vivo. In acinar cells, the Arp2/3 complex and its actin-nucleation activity mediated the formation of a basolateral actin cortex, which is indispensable for ADM and pre-neoplastic transformation. CONCLUSIONS Here, we show that mTORC1 and mTORC2 attain a dual, yet nonredundant regulatory role in ADM and early pancreatic carcinogenesis by promoting Arp2/3 complex function. The role of Arp2/3 complex as a common effector of mTORC1 and mTORC2 fills the gap between oncogenic signals and actin dynamics underlying PDAC initiation.
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MESH Headings
- Acinar Cells/enzymology
- Acinar Cells/pathology
- Actin-Related Protein 2-3 Complex/genetics
- Actin-Related Protein 2-3 Complex/metabolism
- Animals
- Carcinoma, Pancreatic Ductal/enzymology
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/pathology
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Disease Models, Animal
- Gene Expression Regulation, Neoplastic
- Humans
- Mechanistic Target of Rapamycin Complex 1/genetics
- Mechanistic Target of Rapamycin Complex 1/metabolism
- Mechanistic Target of Rapamycin Complex 2/genetics
- Mechanistic Target of Rapamycin Complex 2/metabolism
- Metaplasia
- Mice, Inbred C57BL
- Mice, Knockout
- Mutation
- Pancreatic Ducts/enzymology
- Pancreatic Ducts/pathology
- Pancreatic Neoplasms/enzymology
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/pathology
- Proto-Oncogene Proteins p21(ras)/genetics
- Rapamycin-Insensitive Companion of mTOR Protein/genetics
- Rapamycin-Insensitive Companion of mTOR Protein/metabolism
- Regulatory-Associated Protein of mTOR/genetics
- Regulatory-Associated Protein of mTOR/metabolism
- Signal Transduction
- Mice
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Affiliation(s)
- Yamin Zhao
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Benjamin Schoeps
- Institute of Molecular Immunology and Experimental Oncology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Dianbo Yao
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Zhiheng Zhang
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Kathleen Schuck
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Vivien Tissen
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Carsten Jäger
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | | | - Rob van der Kammen
- Division of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry, Technical University of Munich, Freising, Germany
| | - Jan G D'Haese
- Department of General, Visceral, and Transplantation, Ludwig Maximilians University, Munich, Germany
| | - Susanne Raulefs
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Nadja Maeritz
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Shanshan Shen
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China
| | - Xiaoping Zou
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China
| | - Achim Krüger
- Institute of Molecular Immunology and Experimental Oncology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jörg Kleeff
- Department of Visceral, Vascular and Endocrine Surgery, Martin Luther University Halle-Wittenberg, Germany
| | | | - Helmut Friess
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Metello Innocenti
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - Bo Kong
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China; German Cancer Consortium at the partner site Munich, Munich, Germany.
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20
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Scaiola A, Mangia F, Imseng S, Boehringer D, Berneiser K, Shimobayashi M, Stuttfeld E, Hall MN, Ban N, Maier T. The 3.2-Å resolution structure of human mTORC2. Sci Adv 2020; 6:6/45/eabc1251. [PMID: 33158864 PMCID: PMC7673708 DOI: 10.1126/sciadv.abc1251] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 09/22/2020] [Indexed: 05/22/2023]
Abstract
The protein kinase mammalian target of rapamycin (mTOR) is the central regulator of cell growth. Aberrant mTOR signaling is linked to cancer, diabetes, and neurological disorders. mTOR exerts its functions in two distinct multiprotein complexes, mTORC1 and mTORC2. Here, we report a 3.2-Å resolution cryo-EM reconstruction of mTORC2. It reveals entangled folds of the defining Rictor and the substrate-binding SIN1 subunits, identifies the carboxyl-terminal domain of Rictor as the source of the rapamycin insensitivity of mTORC2, and resolves mechanisms for mTORC2 regulation by complex destabilization. Two previously uncharacterized small-molecule binding sites are visualized, an inositol hexakisphosphate (InsP6) pocket in mTOR and an mTORC2-specific nucleotide binding site in Rictor, which also forms a zinc finger. Structural and biochemical analyses suggest that InsP6 and nucleotide binding do not control mTORC2 activity directly but rather have roles in folding or ternary interactions. These insights provide a firm basis for studying mTORC2 signaling and for developing mTORC2-specific inhibitors.
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Affiliation(s)
- Alain Scaiola
- Institute for Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Francesca Mangia
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Stefan Imseng
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | | | - Karolin Berneiser
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Mitsugu Shimobayashi
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Edward Stuttfeld
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Michael N Hall
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Nenad Ban
- Institute for Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
| | - Timm Maier
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
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21
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Von Walden F, Rea M, Mobley CB, Fondufe-Mittendorf Y, McCarthy JJ, Peterson CA, Murach KA. The myonuclear DNA methylome in response to an acute hypertrophic stimulus. Epigenetics 2020; 15:1151-1162. [PMID: 32281477 PMCID: PMC7595631 DOI: 10.1080/15592294.2020.1755581] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In addition to multi-nucleated muscle fibres, numerous resident and infiltrating mononuclear cells populate the muscle compartment. As most epigenetic assays in skeletal muscle are conducted on whole tissue homogenates, essentially nothing is known about regulatory processes exclusively within muscle fibres in vivo. Utilizing a novel genetically modified mouse model developed by our laboratory, we (1) outline a simple and rapid workflow for isolating pure myonuclei from small tissue samples via fluorescent activated cell sorting and extracting high-quality large-fragment DNA for downstream analyses, and (2) provide information on myonuclear and interstitial cell nuclear CpG DNA methylation via reduced representation bisulphite sequencing (RRBS) using mice that were subjected to an acute mechanical overload of the plantaris muscle. In 3-month-old mice, myonuclei are ~50% of total nuclei in sham and ~30% in 3-d overloaded muscle, the difference being attributable to mononuclear cell infiltration and proliferation with overload. In purified myonuclei, pathway analysis of hypomethylated promoter regions following overload was distinct from interstitial nuclei and revealed marked regulation of factors that converge on the master regulator of muscle growth mTOR, and on autophagy. Specifically, acute hypomethylation of Rheb, Rictor, Hdac1, and Hdac2, in addition to a major driver of ribosome biogenesis Myc, reveals the epigenetic regulation of hypertrophic signalling within muscle fibres that may underpin the long-term growth response to loading. This study provides foundational information on global myonuclear epigenetics in vivo using RRBS, and demonstrates the importance of isolating specific nuclear populations to study the epigenetic regulation of skeletal muscle fibre adaptation.
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Affiliation(s)
- Ferdinand Von Walden
- K6 Department of Women’s and Children’s Health, Karolinska Institute, Stockholm, Sweden
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Matthew Rea
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - C. Brooks Mobley
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | | | - John J. McCarthy
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Charlotte A. Peterson
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Kevin A. Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
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22
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Kim LC, Rhee CH, Chen J. RICTOR Amplification Promotes NSCLC Cell Proliferation through Formation and Activation of mTORC2 at the Expense of mTORC1. Mol Cancer Res 2020; 18:1675-1684. [PMID: 32801163 DOI: 10.1158/1541-7786.mcr-20-0262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/10/2020] [Accepted: 08/07/2020] [Indexed: 11/16/2022]
Abstract
Non-small cell lung cancer (NSCLC) is characterized by genomic alterations, yet a targetable mutation has not been discovered in nearly half of all patients. Recent studies have identified amplification of RICTOR, an mTORC2-specific cofactor, as a novel actionable target in NSCLC. mTORC2 is one of two distinct mTOR complexes to sense environmental cues and regulate a variety of cellular processes, including cell growth, proliferation, and metabolism, all of which promote tumorigenesis when aberrantly regulated. Interestingly, other components of mTORC2 are not coamplified with RICTOR in human lung cancer, raising the question as to whether RICTOR amplification-induced changes are dependent on mTORC2 function. To model RICTOR amplification, we overexpressed Rictor using the Cas9 Synergistic Activation Mediator system. Overexpression of Rictor increased mTORC2 integrity and signaling, but at the expense of mTORC1, suggesting that overexpressed Rictor recruits common components away from mTORC1. Additionally, Rictor overexpression increases the proliferation and growth of NSCLC 3D cultures and tumors in vivo. Conversely, knockout of RICTOR leads to decreased mTORC2 formation and activity, but increased mTORC1 function. Because Rictor has mTOR-dependent and -independent functions, we also knocked out mLST8, a shared mTOR cofactor but is specifically required for mTORC2 function. Inducible loss of mLST8 in RICTOR-amplified NSCLC cells inhibited mTORC2 integrity and signaling, tumor cell proliferation, and tumor growth. Collectively, these data identify a mechanism for Rictor-driven tumor progression and provide further rationale for the development of an mTORC2-specific inhibitor. IMPLICATIONS: RICTOR amplification drives NSCLC proliferation through formation of mTORC2, suggesting mTORC2-specific inhibition could be a beneficial therapeutic option.
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Affiliation(s)
- Laura C Kim
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee
| | | | - Jin Chen
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee.
- Division of Rheumatology and Immunology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
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23
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Watanabe R, Miyata M, Oneyama C. Rictor promotes tumor progression of rapamycin-insensitive triple-negative breast cancer cells. Biochem Biophys Res Commun 2020; 531:636-642. [PMID: 32819718 DOI: 10.1016/j.bbrc.2020.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 08/05/2020] [Indexed: 12/13/2022]
Abstract
Triple-negative breast cancer (TNBC), characterized by decreased expression of hormone receptors and human epidermal growth factor type 2 receptor, has poor prognosis and lacks effective therapeutics. Recently, the mTOR inhibitor rapamycin and its analogs have attracted growing interests and evaluated as therapeutic agents against TNBC, in which the PI3K/AKT/mTOR pathway is often activated. However, some TNBCs are less sensitive to these drugs. In this study, we found that the sensitivity of TNBC cells to rapamycin was highly dependent on the expression level of rapamycin-insensitive companion of mTOR (Rictor), a key component of the mTOR complex 2. Repression of the Rictor expression strongly suppressed the growth of rapamycin-insensitive tumor cells. Furthermore, we showed that the suppression of Rictor expression was also effective in rapamycin-insensitive cells that had acquired resistance to mTOR kinase inhibitors. These findings indicate that Rictor can be a predictive marker for the use of rapamycin analogs in TNBC and highlight the need to develop therapeutics targeting Rictor in the treatment of TNBC.
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Affiliation(s)
- Risayo Watanabe
- Division of Cancer Cell Regulation, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Aichi, Japan
| | - Mamiko Miyata
- Division of Cancer Cell Regulation, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Aichi, Japan
| | - Chitose Oneyama
- Division of Cancer Cell Regulation, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Aichi, Japan; Department of Target and Drug Discovery, Nagoya University, Graduate School of Medicine, Showa-ku, Nagoya, Aichi, Japan; Department of Oncology, Nagoya City University, Graduate School of Pharmaceutical Sciences, Mizuho-ku, Nagoya, Aichi, Japan; JST, PRESTO, Nagoya, Aichi, Japan.
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24
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Sakai H, Murakami C, Usuki T, Lu Q, Matsumoto KI, Urano T, Sakane F. Diacylglycerol kinase η regulates C2C12 myoblast proliferation through the mTOR signaling pathway. Biochimie 2020; 177:13-24. [PMID: 32791090 DOI: 10.1016/j.biochi.2020.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/16/2020] [Accepted: 07/27/2020] [Indexed: 02/08/2023]
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol to produce phosphatidic acid (PA). The η isozyme of DGK is abundantly expressed in C2C12 myoblasts. However, the role of DGKη in skeletal muscle cells remains unknown. In the present study, we showed that DGKη was downregulated at an early stage of myogenic differentiation. The knockdown of DGKη by siRNAs significantly inhibited C2C12 myoblast proliferation but did not inhibit differentiation. Moreover, the suppression of DGKη expression decreased the expression levels of mammalian target of rapamycin (mTOR), which is a key regulator of cell proliferation, and fatty acid synthase (FASN), which catalyzes the de novo synthesis of fatty acids for cell proliferation and is transcriptionally regulated via mTOR signaling. Furthermore, the knockdown of mTOR or raptor, which is a component of mTOR complex 1 (mTORC1), decreased the amount of FASN. These results indicate that DGKη regulates myoblast proliferation through the mTOR (mTORC1)-FASN pathway. Interestingly, the knockdown of mTOR reduced the expression levels of DGKη, implying mutual regulation between DGKη and mTOR. In DGKη-knockdown myoblasts, C30-C36-PA species, mTOR activators, were decreased, suggesting that the modulation of mTOR activity through these PA species also plays an important role in myoblast proliferation.
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Affiliation(s)
- Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan.
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Takako Usuki
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Qiang Lu
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Ken-Ichi Matsumoto
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan
| | - Takeshi Urano
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan; Department of Biochemistry, Shimane University School of Medicine, Izumo, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan.
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25
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Entwisle SW, Martinez Calejman C, Valente AS, Lawrence RT, Hung CM, Guertin DA, Villén J. Proteome and Phosphoproteome Analysis of Brown Adipocytes Reveals That RICTOR Loss Dampens Global Insulin/AKT Signaling. Mol Cell Proteomics 2020; 19:1104-1119. [PMID: 32234964 PMCID: PMC7338085 DOI: 10.1074/mcp.ra120.001946] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/19/2020] [Indexed: 11/06/2022] Open
Abstract
Stimulating brown adipose tissue (BAT) activity represents a promising therapy for overcoming metabolic diseases. mTORC2 is important for regulating BAT metabolism, but its downstream targets have not been fully characterized. In this study, we apply proteomics and phosphoproteomics to investigate the downstream effectors of mTORC2 in brown adipocytes. We compare wild-type controls to isogenic cells with an induced knockout of the mTORC2 subunit RICTOR (Rictor-iKO) by stimulating each with insulin for a 30-min time course. In Rictor-iKO cells, we identify decreases to the abundance of glycolytic and de novo lipogenesis enzymes, and increases to mitochondrial proteins as well as a set of proteins known to increase upon interferon stimulation. We also observe significant differences to basal phosphorylation because of chronic RICTOR loss including decreased phosphorylation of the lipid droplet protein perilipin-1 in Rictor-iKO cells, suggesting that RICTOR could be involved with regulating basal lipolysis or droplet dynamics. Finally, we observe mild dampening of acute insulin signaling response in Rictor-iKO cells, and a subset of AKT substrates exhibiting statistically significant dependence on RICTOR.
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Affiliation(s)
- Samuel W Entwisle
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington; Department of Genome Sciences, University of Washington, Seattle, Washington
| | | | - Anthony S Valente
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Robert T Lawrence
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington; Department of Genome Sciences, University of Washington, Seattle, Washington
| | | | | | - Judit Villén
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington; Department of Genome Sciences, University of Washington, Seattle, Washington.
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Venugopal SV, Caggia S, Gambrell-Sanders D, Khan SA. Differential roles and activation of mammalian target of rapamycin complexes 1 and 2 during cell migration in prostate cancer cells. Prostate 2020; 80:412-423. [PMID: 31995655 PMCID: PMC7232714 DOI: 10.1002/pros.23956] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 01/15/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND Mammalian target of rapamycin (mTOR) is a downstream substrate activated by PI3K/AKT pathway and it is essential for cell migration. It exists as two complexes: mTORC1 and mTORC2. mTORC1 is known to be regulated by active AKT, but the activation of mTORC2 is poorly understood. In this study, we investigated the roles and differential activation of the two mTOR complexes during cell migration in prostate cancer cells. METHODS We used small interfering RNA to silence the expression of Rac1 and the main components of mTOR complexes (regulatory associated protein of mTOR [RAPTOR] and rapamycin-insensitive companion of mTOR [RICTOR]) in LNCaP, DU145, and PC3 prostate cancer cell lines. We performed transwell migration assay to evaluate the migratory capability of the cells, and Western blot analysis to study the activation levels of mTOR complexes. RESULTS Specific knockdown of RAPTOR and RICTOR caused a decrease of cell migration, suggesting their essential role in prostate cancer cell movement. Furthermore, epidermal growth factor (EGF) treatments induced the activation of both the mTOR complexes. Lack of Rac1 activity in prostate cancer cells blocked EGF-induced activation of mTORC2, but had no effect on mTORC1 activation. Furthermore, the overexpression of constitutively active Rac1 resulted in significant increase in cell migration and activation of mTORC2 in PC3 cells, but had no effect on mTORC1 activation. Active Rac1 was localized in the plasma membrane and was found to be in a protein complex, with RICTOR, but not RAPTOR. CONCLUSION We suggest that EGF-induced activation of Rac1 causes the activation of mTORC2 via RICTOR. This mechanism plays a critical role in prostate cancer cell migration.
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Affiliation(s)
- Smrruthi Vaidegi Venugopal
- Department of biological sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia
| | - Silvia Caggia
- Department of biological sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia
| | - DaJhnae Gambrell-Sanders
- Department of biological sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia
| | - Shafiq A Khan
- Department of biological sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia
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McCabe MP, Cullen ER, Barrows CM, Shore AN, Tooke KI, Laprade KA, Stafford JM, Weston MC. Genetic inactivation of mTORC1 or mTORC2 in neurons reveals distinct functions in glutamatergic synaptic transmission. eLife 2020; 9:e51440. [PMID: 32125271 PMCID: PMC7080408 DOI: 10.7554/elife.51440] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 03/02/2020] [Indexed: 12/13/2022] Open
Abstract
Although mTOR signaling is known as a broad regulator of cell growth and proliferation, in neurons it regulates synaptic transmission, which is thought to be a major mechanism through which altered mTOR signaling leads to neurological disease. Although previous studies have delineated postsynaptic roles for mTOR, whether it regulates presynaptic function is largely unknown. Moreover, the mTOR kinase operates in two complexes, mTORC1 and mTORC2, suggesting that mTOR's role in synaptic transmission may be complex-specific. To better understand their roles in synaptic transmission, we genetically inactivated mTORC1 or mTORC2 in cultured mouse glutamatergic hippocampal neurons. Inactivation of either complex reduced neuron growth and evoked EPSCs (eEPSCs), however, the effects of mTORC1 on eEPSCs were postsynaptic and the effects of mTORC2 were presynaptic. Despite postsynaptic inhibition of evoked release, mTORC1 inactivation enhanced spontaneous vesicle fusion and replenishment, suggesting that mTORC1 and mTORC2 differentially modulate postsynaptic responsiveness and presynaptic release to optimize glutamatergic synaptic transmission.
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Affiliation(s)
- Matthew P McCabe
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - Erin R Cullen
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - Caitlynn M Barrows
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - Amy N Shore
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - Katherine I Tooke
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - Kathryn A Laprade
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - James M Stafford
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
| | - Matthew C Weston
- University of Vermont, Department of Neurological SciencesBurlingtonUnited States
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Wang Y, Tang S, Wu Y, Wan X, Zhou M, Li H, Zha X. Upregulation of 6-phosphofructo-2-kinase (PFKFB3) by hyperactivated mammalian target of rapamycin complex 1 is critical for tumor growth in tuberous sclerosis complex. IUBMB Life 2020; 72:965-977. [PMID: 31958214 DOI: 10.1002/iub.2232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 01/06/2020] [Indexed: 12/19/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterized by the benign tumor formation in multiple organs. The main etiology of TSC is the loss-of-function mutation of TSC1 or TSC2 gene, which leads to aberrant activation of mammalian target of rapamycin complex 1 (mTORC1). In this research, we found a significant increase of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) expression in Tsc1-/- and Tsc2-/- mouse embryonic fibroblasts (MEFs) compared with the control cells. Inhibition of mTORC1 led to a dramatic decrease of PFKFB3 expression, indicating PFKFB3 regulation by mTORC1. Moreover, suppression of mTORC1 inhibited the expression of PFKFB3 in rat uterine leiomyoma-derived Tsc2-null ELT3 cells and human tumor cells. Furthermore, we identified hypoxia-inducible factor 1α (HIF-1α) as a mediator transmitting the signal from mTORC1 to PFKFB3. Depletion of PFKFB3 inhibited proliferation and tumorigenicity of Tsc1- or Tsc2-deficient cells. In addition, combination of rapamycin with PFK15, a PFKFB3 inhibitor, exerts a stronger inhibitory effect on cell proliferation of Tsc1- or Tsc2-null MEFs than treatment with single drug. We conclude that loss of TSC1 or TSC2 led to upregulated expression of PFKFB3 through activation of mTORC1/HIF-1α signaling pathway and co-administration of rapamycin and PFK15 may be a promising strategy for the treatment of TSC tumors as well as other hyperactivated mTORC1-related tumors.
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Affiliation(s)
- Yani Wang
- Department of Biochemistry & Molecular Biology, School of Basic Medicine, Anhui Medical University, Hefei, China
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Sisi Tang
- Department of Biochemistry & Molecular Biology, School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Yuncui Wu
- Department of Biochemistry & Molecular Biology, School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Xiaofeng Wan
- Department of Biochemistry & Molecular Biology, School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Meng Zhou
- Department of Biochemistry & Molecular Biology, School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Hongwu Li
- Department of Otorhinolaryngology, Head & Neck Surgery, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xiaojun Zha
- Department of Biochemistry & Molecular Biology, School of Basic Medicine, Anhui Medical University, Hefei, China
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Abstract
Context: Evidence suggests that microRNA (miRNA) regulate gene expression and bone tissue homoeostasis of osteoporosis. MiR-152 has found to be abnormally expressed in osteoporosis, but its role in osteoblast differentiation has not been elucidated. Objective: To understand the potential mechanism of miR-152 in osteoblast differentiation via regulation of RICTOR. Materials and methods: The expression of miR-152 and RICTOR were tested in ovariectomized rat models of osteoporosis. Primary osteoblasts and MC3T -E1 cells were assigned into four groups, namely Control, miR-152 inhibitor, miR-control and miR-152 inhibitor + siRICTOR groups. qRT PCR and Western blot were performed to detect the expressions of miR-152 and RICTOR, respectively. MTT assay was used to evaluate cell viability, and ALP activity determination and mineralization analyses were also conducted. Results: In ovariectomy-induced osteoporotic rats, miR-152 (3.06 ± 0.35) in femoral tissues increased significantly, while RICTOR (0.31 ± 0.04) decreased. Compared with Control group, miR-152 inhibitor group presented appreciable reduction of miR-152 in primary osteoblasts and MC3T3-E1 cells, as well as remarkable increases in RICTOR, p-Akt(s473)/Akt ratio, and osteogenesis-related genes, with enhanced cell viability, ALP activity and mineralization. In comparison with cells in the miR-152 inhibitor group, those in the miR-152 inhibitor + siRICTOR group had no observable difference in miR-152, but were dramatically up-regulated in RICTOR, as well as the corresponding opposite tendencies of other factors. Conclusion: Inhibiting miR-152 promoted osteoblasts differentiation and alleviated osteoporosis by up-regulating RICTOR. Therefore, miR-152 may be an essential mediator of osteoblast differentiation and a new therapeutic strategy for osteoporosis.
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Affiliation(s)
- Li Feng
- Department of Traumatic Orthopedics, Jining No. 1 People’s Hospital, Jining, China
| | - Bo Xia
- Department of Traumatic Orthopedics, Jining No. 1 People’s Hospital, Jining, China
| | - Bao-Fang Tian
- Department of Traumatic Orthopedics, Jining No. 1 People’s Hospital, Jining, China
| | - Gong-Biao Lu
- Department of Spine Surgery, Jining No, 1 People’s Hospital, Jining, China
- CONTACT Gong-Biao Lu Department of Spine Surgery, Jining No. 1 People’s Hospital, No.6, Jiankang Road, Jining, Shandong 272011, China
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Ruicci KM, Plantinga P, Pinto N, Khan MI, Stecho W, Dhaliwal SS, Yoo J, Fung K, MacNeil D, Mymryk JS, Barrett JW, Howlett CJ, Nichols AC. Disruption of the RICTOR/mTORC2 complex enhances the response of head and neck squamous cell carcinoma cells to PI3K inhibition. Mol Oncol 2019; 13:2160-2177. [PMID: 31393061 PMCID: PMC6763779 DOI: 10.1002/1878-0261.12558] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 07/28/2019] [Accepted: 08/07/2019] [Indexed: 12/19/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) is aberrantly activated in head and neck squamous cell carcinomas (HNSCC) and plays a pivotal role in tumorigenesis by driving Akt signaling, leading to cell survival and proliferation. Phosphorylation of Akt Thr308 by PI3K-PDK1 and Akt Ser473 by mammalian target of rapamycin complex 2 (mTORC2) activates Akt. Targeted inhibition of PI3K is a major area of preclinical and clinical investigation as it reduces Akt Thr308 phosphorylation, suppressing downstream mTORC1 activity. However, inhibition of mTORC1 releases feedback inhibition of mTORC2, resulting in a resurgence of Akt activation mediated by mTORC2. While the role of PI3K-activated Akt signaling is well established in HNSCC, the significance of mTORC2-driven Akt signaling has not been thoroughly examined. Here we explore the expression and function of mTORC2 and its obligate subunit RICTOR in HNSCC primary tumors and cell lines. We find RICTOR to be overexpressed in a subset of HNSCC tumors, including those with PIK3CA or EGFR gene amplifications. Whereas overexpression of RICTOR reduced susceptibility of HNSCC tumor cells to PI3K inhibition, genetic ablation of RICTOR using CRISPR/Cas9 sensitized cells to PI3K inhibition, as well as to EGFR inhibition and cisplatin treatment. Further, mTORC2 disruption led to reduced viability and colony forming abilities of HNSCC cells relative to their parental lines and induced loss of both activating Akt phosphorylation modifications (Thr308 and Ser473). Taken together, our findings establish RICTOR/mTORC2 as a critical oncogenic complex in HNSCC and rationalize the development of an mTORC2-specific inhibitor for use in HNSCC, either combined with agents already under investigation, or as an independent therapy.
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Affiliation(s)
- Kara M. Ruicci
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Paul Plantinga
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Nicole Pinto
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Mohammed I. Khan
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - William Stecho
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Sandeep S. Dhaliwal
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Oncology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - John Yoo
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Oncology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Kevin Fung
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Oncology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Danielle MacNeil
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Oncology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Joe S. Mymryk
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Oncology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Microbiology and Immunology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - John W. Barrett
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Christopher J. Howlett
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
| | - Anthony C. Nichols
- Department of Otolaryngology – Head and Neck Surgery, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
- Department of Oncology, Schulich School of Medicine & DentistryWestern UniversityLondonCanada
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SHAO Y, WANG J, ZHU D. [Rictor regulates mitochondrial calcium signaling in mouse embryo stem cell-derived cardiomyocytes]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2019; 48:65-74. [PMID: 31102360 PMCID: PMC8800653 DOI: 10.3785/j.issn.1008-9292.2019.02.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/12/2018] [Indexed: 06/09/2023]
Abstract
OBJECTIVE To explore the expression, localization and regulatory effect on mitochondrial calcium signaling of Rictor in embryonic stem cell-derived cardiomyocytes (ESC-CMs). METHODS Classical embryonic stem cell cardiomyogenesis model was used for differentiation of mouse embryonic stem cells into cardiomyocytes. The location of Rictor in ESC-CMs was investigated by immunofluorescence and Western blot. The expression of Rictor in mouse embryonic stem cells was interfered with lentiviral technology, then the superposition of mitochondria and endoplasmic reticulum (ER) in ESC-CMs was detected with immunofluorescence method; the cellular ultrastructure of ESC-CMs was observed by transmission electron microscope; the mitochondrial calcium transients of ESC-CMs was detected by living cell workstation;immunoprecipitation was used to detect the interaction between 1,5,5-trisphosphate receptor (IP3 receptor, IP3R), glucose-regulated protein 75 (Grp75) and voltage-dependent anion channel 1 (VDAC1) in mitochondrial outer membrane; the expression of mitochondrial fusion protein (mitonusin-2, Mfn2) was detected by Western blot. RESULTS Rictor was mainly localized in the endoplasmic reticulum and mitochondrial-endoplasmic reticulum membrane (MAM) in ESC-CMs. Immunofluorescence results showed that Rictor was highly overlapped with ER and mitochondria in ESC-CMs. After mitochondrial and ER were labeled with Mito-Tracker Red and ER-Tracker Green, it was demonstrated that the mitochondria of the myocardial cells in the Rictor group were scattered, and the superimposition rate of mitochondria and ER was lower than that of the negative control group (P<0.01). The MAM structures were decreased in ESC-CMs after knockdown of Rictor. The results of the living cell workstation showed that the amplitude of mitochondrial calcium transients by ATP stimulation in ESC-CMs was decreased after knockdown of Rictor (P<0.01). The results of co-immunoprecipitation showed that the interaction between IP3R, Grp75 and VDAC1 in the MAM structure of the cardiomyocytes in the Rictor group was significantly attenuated (P<0.01); the results of Western blot showed that the expression of Mfn2 protein was significantly decreased (P<0.01). CONCLUSIONS Using lentiviral technology to interfere Rictor expression in mouse embryonic stem cells, the release of calcium from the endoplasmic reticulum to mitochondria in ESC-CMs decreases, which may be affected by reducing the interaction of IP3R, Grp75, VDAC1 and decreasing the expression of Mfn2, leading to the damage of MAM structure.
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Harwood FC, Klein Geltink RI, O’Hara BP, Cardone M, Janke L, Finkelstein D, Entin I, Paul L, Houghton PJ, Grosveld GC. ETV7 is an essential component of a rapamycin-insensitive mTOR complex in cancer. Sci Adv 2018; 4:eaar3938. [PMID: 30258985 PMCID: PMC6156121 DOI: 10.1126/sciadv.aar3938] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 08/03/2018] [Indexed: 05/14/2023]
Abstract
The mechanistic target of rapamycin (mTOR) serine/threonine kinase, a critical regulator of cell proliferation, is frequently deregulated in human cancer. Although rapamycin inhibits the two canonical mTOR complexes, mTORC1 and mTORC2, it often shows minimal benefit as an anticancer drug. This is caused by rapamycin resistance of many different tumors, and we show that a third mTOR complex, mTORC3, contributes to this resistance. The ETS (E26 transformation-specific) transcription factor ETV7 interacts with mTOR in the cytoplasm and assembles mTORC3, which is independent of ETV7's transcriptional activity. This complex exhibits bimodal mTORC1/2 activity but is devoid of crucial mTORC1/2 components. Many human cancers activate mTORC3 at considerable frequency, and tumor cell lines that lose mTORC3 expression become rapamycin-sensitive. We show mTORC3's tumorigenicity in a rhabdomyosarcoma mouse model in which transgenic ETV7 expression accelerates tumor onset and promotes tumor penetrance. Discovery of mTORC3 represents an mTOR paradigm shift and identifies a novel target for anticancer drug development.
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Affiliation(s)
- Franklin C. Harwood
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | | | - Brendan P. O’Hara
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Monica Cardone
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Laura Janke
- Department of Veterinary Pathology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - David Finkelstein
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Igor Entin
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Leena Paul
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Peter J. Houghton
- Greehey Children’s Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Gerard C. Grosveld
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
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Zhang BF, Hu Y, Liu X, Cheng Z, Lei Y, Liu Y, Zhao X, Mu M, Yu L, Cheng ML. The role of AKT and FOXO3 in preventing ovarian toxicity induced by cyclophosphamide. PLoS One 2018; 13:e0201136. [PMID: 30071053 PMCID: PMC6071999 DOI: 10.1371/journal.pone.0201136] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/08/2018] [Indexed: 12/11/2022] Open
Abstract
Cyclophosphamide (CTX) has immunosuppressive effects and has been wildly used as one anti-cancer drug in clinical. Significant toxicity has been noticed particularly in the reproductive system. CTX promotes the maturation of ovarian follicles, decreases follicular reserve, and ultimately lead to ovarian failure or even premature ovarian failure (POF). The placental extract (HPE) has been shown to have some beneficial impact on reproductive system; however, little is known regarding to the effect of HPE on protecting CTX-induced ovarian injury and the mechanism involved. Whether human placental extracts (HPE) has a protective effect on CTX-induced toxicity on ovarian was studied by using a CTX-induced ovarian injury animal model. The effects of HEP on histopathology, the number of atretic follicles, the weight of the ovary, serum hormone levels, and apoptosis in granulosa cells were studied in mice with CTX or control vehicle. Our results have demonstrated that HPE inhibited p-Rictor, reduced the expression of Bad, Bax and PPAR, and activated Akt and Foxo3a (increased their phosphorylation). Mice treated with HPE showed higher ovarian weight, lower number of atretic follicles, higher serum levels of the hormones E2 and progesterone, and lower apoptosis and serum levels of LH and FSH in granulosa cells, than that in the control animal group. Our data show that ovarian injury can be attenuated by HPE. HPE likely protects follicular granulosa cells from undergoing significant apoptosis and reduce atresia follicle formation, therefore, alleviates CTX-induced ovarian injury.
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Affiliation(s)
- Bao-fang Zhang
- The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, China
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - YaXin Hu
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - Xinyan Liu
- Shandong Institute of Biological Products,Taishan district, Shandong, China
| | - Zhuo Cheng
- Peking University Health Science Center School of Foundational Education, Beijing,China
| | - Yu Lei
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - YongMei Liu
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - Xueke Zhao
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - Mao Mu
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - Lei Yu
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
| | - Ming-liang Cheng
- The Affiliated Hospital, Guizhou Medical University, Guiyang, Guizhou, China
- * E-mail: (LY); (MLC)
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Hamidian A, Vaapil M, von Stedingk K, Fujita T, Persson CU, Eriksson P, Veerla S, De Preter K, Speleman F, Fujii H, Påhlman S, Mohlin S. Promoter-associated proteins of EPAS1 identified by enChIP-MS - A putative role of HDX as a negative regulator. Biochem Biophys Res Commun 2018; 499:291-298. [PMID: 29577908 DOI: 10.1016/j.bbrc.2018.03.150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022]
Abstract
Presence of perivascular neuroblastoma cells with high expression of hypoxia inducible factor (HIF)-2α correlates with distant metastasis and aggressive disease. Regulation of HIFs are traditionally considered to occur post-translationally, but we have recently shown that HIF-2α is unconventionally regulated also at the transcriptional level in neuroblastoma cells. Regulatory factors binding directly to EPAS1 (encoding HIF-2α) to promote transcription are yet to be defined. Here, we employ the novel CRISPR/Cas9-based engineered DNA-binding molecule-mediated chromatin immunoprecipitation (enChIP) - mass spectrometry (MS) methodology to, in an unbiased fashion, identify proteins that associate with the EPAS1 promoter under normoxic and hypoxic conditions. Our enChIP analysis resulted in 27 proteins binding to the EPAS1 promoter in neuroblastoma cells. In agreement with a general hypoxia-driven downregulation of gene transcription, the majority (24 out of 27) of proteins dissociate from the promoter at hypoxia. Among them were several nucleosome-associated proteins suggesting a general opening of chromatin as one explanation to induced EPAS1 transcription at hypoxia. Of particular interest from the list of released factors at hypoxia was the highly divergent homeobox (HDX) transcription factor, that we show inversely correlates with HIF-2α in neuroblastoma cells. We propose a putative model where HDX negatively regulates EPAS1 expression through a release-of-inhibition mechanism.
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Affiliation(s)
- Arash Hamidian
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - Marica Vaapil
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | | | - Toshitsugu Fujita
- Combined Program on Microbiology and Immunology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka 3-1, Suita City, Osaka, 565-0871, Japan; Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, Aomori Prefecture, 036-8562, Japan
| | - Camilla U Persson
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - Pontus Eriksson
- Department of Oncology and Pathology, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Srinivas Veerla
- Department of Oncology and Pathology, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Katleen De Preter
- Center for Medical Genetics, Ghent University, Ghent, B-9000, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University, B-9000, Ghent, Belgium
| | - Frank Speleman
- Center for Medical Genetics, Ghent University, Ghent, B-9000, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University, B-9000, Ghent, Belgium
| | - Hodaka Fujii
- Combined Program on Microbiology and Immunology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka 3-1, Suita City, Osaka, 565-0871, Japan; Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, Aomori Prefecture, 036-8562, Japan
| | - Sven Påhlman
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - Sofie Mohlin
- Department of Pediatrics, Clinical Sciences, Lund University, Lund, Sweden.
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Xu D, Zhu J, Jeong S, Li D, Hua X, Huang L, Zhang J, Luo Y, Xia Q. Rictor Deficiency Aggravates Hepatic Ischemia/Reperfusion Injury in Mice by Suppressing Autophagy and Regulating MAPK Signaling. Cell Physiol Biochem 2018; 45:2199-2212. [PMID: 29550823 DOI: 10.1159/000488165] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 01/16/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The role of Rictor in hepatic ischemia/reperfusion (I/R) injury remains unknown. Here, we comprehensively examined the role of Rictor in hepatic I/R injury. METHODS We studied the expression of Rictor during hepatic I/R injury. The regulatory effects of Rictor on inflammatory responses, cytokine and chemokine release, apoptotic and anti-apoptotic responses, and autophagy induction during hepatic I/R injury were identified via the shRNA-mediated knockdown of Rictor. Subsequently, we collected the liver and blood samples of these mice to evaluate liver injury, mRNA and protein levels. Additionally, the signaling pathways induced by Rictor were investigated. Furthermore, the extent of activation of MAPKs in response to Rictor deficiency was investigated in lipopolysaccharide (LPS)-treated RAW264.7 cells. The mRNA expression levels were analyzed by real-time PCR, and the protein expression levels were analyzed using Western blot, immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA). RESULTS The expression of Rictor was increased during hepatic I/R injury in vivo and hypoxia/reoxygenation (H/R) injury in vitro. Rictor deficiency enhanced the extent of liver injury by increasing macrophage and neutrophil infiltration, promoting cytokine and chemokine release, aggravating hepatocyte apoptosis, suppressing anti-apoptotic responses, and inhibiting autophagy induction during both hepatic I/R and H/R injury. Rictor was associated with the activation of hepatic I/R injury-induced MAPK signaling. In addition, Rictor deficiency affected MAPK activation in LPS-treated RAW264.7 cells. CONCLUSION Rictor can substantially ameliorate I/R-induced liver injury. Therefore, our findings strongly suggest a therapeutic value of the Rictor/mTORC2 axis in hepatic I/R injury.
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董 合, 吴 洪, 傅 友, 戴 萌, 白 晓, 王 红. [Rictor/mTORC2 regulates blood-testis barrier and spermatogenesis in mice]. Nan Fang Yi Ke Da Xue Xue Bao 2017; 37:1322-1329. [PMID: 29070461 PMCID: PMC6743948 DOI: 10.3969/j.issn.1673-4254.2017.10.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To investigate the role of Rictor/mTORC2 in the formation of blood testis barrier (BTB), testicular development, and spermatogenesis. METHODS Amh Cre positive mice homozygous for rictor loxP with Sertoli cell specific deletion of rictor were obtained by cross breeding Amh Cre mice with rictor loxP mice. The histology of the reproductive organs, seminiferous tubules and epididymis of the transgenic mice was observed with HE staining. The cell subgroups of the germ cells in the seminiferous tubule were detected by flow cytometry with propidium iodide labeling. The expression levels of Ki 67 and separase were detected with immunofluorescence assay, and the expression levels of BTB associated proteins were detected with immunofluorescence and Western blotting. RESULTS Compared with the control (Amh Cre-, rictorloxP/loxP or rictorloxP/-) mice, the mice with Sertoli cell specific rictor deletion showed significantly decreased testicular weight and epididymis weight (P<0.05), significantly increased diploid cells (P<0.01), and decreased haploid cells (P<0.01) but comparable tetraploid cells and similar expression levels of Ki 67 and separase. The mice with rictor knockout also showed aberrant localization of BTB associated proteins, which were scattered over the whole seminiferous epithelium, but the expression levels of the protein remained stable. CONCLUSION Rictor in testicular Sertoli cells is essential for maintaining BTB integrity and function and ensuring normal spermatogenesis in mice.
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Affiliation(s)
- 合玲 董
- 暨南大学体育学院, 广东 广州 510632College of Sports Science, Jinan University, Guangzhou 510632, China
| | - 洪渊 吴
- 南方医科大学南方医院健康管理科, 广东 广州 510515Department of Health Management, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 友 傅
- 南方医科大学南方医院健康管理科, 广东 广州 510515Department of Health Management, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 萌 戴
- 南方医科大学南方医院健康管理科, 广东 广州 510515Department of Health Management, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 晓春 白
- 南方医科大学细胞生物学教研室, 广东 广州 510515Southern Medical University, Department of Cell Biology, Southern Medical University, Guangzhou 510515, China
| | - 红 王
- 南方医科大学第三附属医院, 广东省骨科研究院, 广东 广州 510630Academy of Orthopedics of Guangdong Province, Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China
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Thomas KT, Anderson BR, Shah N, Zimmer SE, Hawkins D, Valdez AN, Gu Q, Bassell GJ. Inhibition of the Schizophrenia-Associated MicroRNA miR-137 Disrupts Nrg1α Neurodevelopmental Signal Transduction. Cell Rep 2017; 20:1-12. [PMID: 28683304 PMCID: PMC5745041 DOI: 10.1016/j.celrep.2017.06.038] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 04/28/2017] [Accepted: 06/13/2017] [Indexed: 12/14/2022] Open
Abstract
Genomic studies have repeatedly associated variants in the gene encoding the microRNA miR-137 with increased schizophrenia risk. Bioinformatic predictions suggest that miR-137 regulates schizophrenia-associated signaling pathways critical to neural development, but these predictions remain largely unvalidated. In the present study, we demonstrate that miR-137 regulates neuronal levels of p55γ, PTEN, Akt2, GSK3β, mTOR, and rictor. All are key proteins within the PI3K-Akt-mTOR pathway and act downstream of neuregulin (Nrg)/ErbB and BDNF signaling. Inhibition of miR-137 ablates Nrg1α-induced increases in dendritic protein synthesis, phosphorylated S6, AMPA receptor subunits, and outgrowth. Inhibition of miR-137 also blocks mTORC1-dependent responses to BDNF, including increased mRNA translation and dendritic outgrowth, while leaving mTORC1-independent S6 phosphorylation intact. We conclude that miR-137 regulates neuronal responses to Nrg1α and BDNF through convergent mechanisms, which might contribute to schizophrenia risk by altering neural development.
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Affiliation(s)
- Kristen Therese Thomas
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Bart Russell Anderson
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Niraj Shah
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Stephanie Elaine Zimmer
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Daniel Hawkins
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Arielle Nicole Valdez
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Qiaochu Gu
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Gary Jonathan Bassell
- Department of Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA.
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Liu DM, Zhao L, Liu TT, Jiao PL, Zhao DD, Shih MS, Tao B, Sun LH, Zhao HY, Liu JM. Rictor/mTORC2 loss in osteoblasts impairs bone mass and strength. Bone 2016; 90:50-8. [PMID: 27262777 DOI: 10.1016/j.bone.2016.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 05/25/2016] [Accepted: 05/29/2016] [Indexed: 11/26/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a Ser/Thr kinase conserved through evolution that coordinates extra cellular signals associated with cell growth. Main functions of mTOR present in the form of two complexes, namely mTORC1 and mTORC2, which are distinct in their unique components, raptor and rictor. In the current study, using a Cre/loxp system, we found an anabolic effect of mTORC2 signaling on skeleton. Osteoblast differentiation was reduced, with down-regulation of mTORC2 signaling activity in primary cultures of osteoblasts that did not contain rictor. Mice with a specific deletion of rictor in mature osteoblasts showed a significant reduction in lean mass and bone mineral density by dual energy x-ray absorptiometry analysis. Micro-computed tomography, histomorphometric, and molecular biological analyses revealed a marked impairment of the cortical bone mass and microarchitecture, as well as minor changes in trabecular bone, of the Rictorob(-/-) mice. Cortical bone mass and thickness of the femoral mid-shaft were dramatically reduced, with unusual increases in porosity and marrow area in Rictorob(-/-) mice. Thinner trabeculae were found in the L4 vertebrae with relatively normal structural indices of trabecular numbers and separation. A lower rate of bone turnover was observed, as the consequence of the decreased individual osteoblast activity and bone resorption. Furthermore, these changes were associated with significantly decreased bone biomechanical properties. In conclusion, expression of rictor in osteoblasts is essential for the maintenance of normal bone remodeling and microarchitecture, especially for the maintenance of the cortical bone.
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Affiliation(s)
- Dong-Mei Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Lin Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China; Department of Endocrine and Metabolic Diseases, ZhongShan Hospital, FuDan University, Shanghai, China
| | - Ting-Ting Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Pei-Lin Jiao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Dian-Dian Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Mei-Shu Shih
- PharmaLegacy Laboratories Co., Ltd., Shanghai, China
| | - Bei Tao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Li-Hao Sun
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Hong-Yan Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Jian-Min Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China.
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