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Zhang Y, Wen J, Lai R, Zhang J, Li K, Zhang Y, Liu A, Bai X. Rheb1 is required for limb growth through regulating chondrogenesis in growth plate. Cell Tissue Res 2024; 395:261-269. [PMID: 38253890 PMCID: PMC10904423 DOI: 10.1007/s00441-024-03861-2] [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: 11/29/2022] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
Ras homology enriched in the brain (Rheb) is well established as a critical regulator of cell proliferation and differentiation in response to growth factors and nutrients. However, the role of Rheb1 in limb development remains unknown. Here, we found that Rheb1 was dynamically expressed during the proliferation and differentiation of chondrocytes in the growth plate. Given that Prrx1+ limb-bud-like mesenchymal cells are the source of limb chondrocytes and are essential for endochondral ossification, we conditionally deleted Rheb1 using Prrx1-Cre and found a limb dwarfism in Prrx1-Cre; Rheb1fl/fl mice. Normalized to growth plate height, the conditional knockout (cKO) mice exhibited a significant decrease in column count of proliferative zones which was increased in hypertrophic zones resulting in decreased growth plate size, indicating abnormal endochondral ossification. Interestingly, although Rheb1 deletion profoundly inhibited the transcription factor Sox9 in limb cartilage; levels of runx2 and collagen type 2 were both increased. These novel findings highlight the essential role of Rheb1 in limb growth and indicate a complex regulation of Rheb1 in chondrocyte proliferation and differentiation.
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Affiliation(s)
- Yuwei Zhang
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Jiaxin Wen
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Ruijun Lai
- The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Jiahuan Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510000, People's Republic of China
| | - Kai Li
- The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Yue Zhang
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
| | - Anling Liu
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
| | - Xiaochun Bai
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
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2
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Rahman M, Nguyen TM, Lee GJ, Kim B, Park MK, Lee CH. Unraveling the Role of Ras Homolog Enriched in Brain ( Rheb1 and Rheb2): Bridging Neuronal Dynamics and Cancer Pathogenesis through Mechanistic Target of Rapamycin Signaling. Int J Mol Sci 2024; 25:1489. [PMID: 38338768 PMCID: PMC10855792 DOI: 10.3390/ijms25031489] [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: 12/15/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 02/12/2024] Open
Abstract
Ras homolog enriched in brain (Rheb1 and Rheb2), small GTPases, play a crucial role in regulating neuronal activity and have gained attention for their implications in cancer development, particularly in breast cancer. This study delves into the intricate connection between the multifaceted functions of Rheb1 in neurons and cancer, with a specific focus on the mTOR pathway. It aims to elucidate Rheb1's involvement in pivotal cellular processes such as proliferation, apoptosis resistance, migration, invasion, metastasis, and inflammatory responses while acknowledging that Rheb2 has not been extensively studied. Despite the recognized associations, a comprehensive understanding of the intricate interplay between Rheb1 and Rheb2 and their roles in both nerve and cancer remains elusive. This review consolidates current knowledge regarding the impact of Rheb1 on cancer hallmarks and explores the potential of Rheb1 as a therapeutic target in cancer treatment. It emphasizes the necessity for a deeper comprehension of the molecular mechanisms underlying Rheb1-mediated oncogenic processes, underscoring the existing gaps in our understanding. Additionally, the review highlights the exploration of Rheb1 inhibitors as a promising avenue for cancer therapy. By shedding light on the complicated roles between Rheb1/Rheb2 and cancer, this study provides valuable insights to the scientific community. These insights are instrumental in guiding the identification of novel targets and advancing the development of effective therapeutic strategies for treating cancer.
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Affiliation(s)
- Mostafizur Rahman
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Tuan Minh Nguyen
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Gi Jeong Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Boram Kim
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Mi Kyung Park
- Department of BioHealthcare, Hwasung Medi-Science University, Hwaseong-si 18274, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
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Taherian M, Bayati P, Assarehzadegan MA, Soleimani M, Poormoghim H, Mojtabavi N. Insights into Overlappings of Fibrosis and Cancer: Exploring the Tumor-related Cardinal Genes in Idiopathic Pulmonary Fibrosis. Iran J Allergy Asthma Immunol 2023; 22:190-199. [PMID: 37496412 DOI: 10.18502/ijaai.v22i2.12680] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/03/2023] [Indexed: 07/28/2023]
Abstract
The pathogenesis of idiopathic pulmonary fibrosis (IPF) is quite similar to that of cancer pathogenesis, and several pathways appear to be involved in both disorders. The mammalian target of the rapamycin (mTOR) pathway harbors several established oncogenes and tumor suppressors. The same signaling molecules and growth factors, such as vascular endothelial growth factor (VEGF), contributing to cancer development and progression play a part in fibroblast proliferation, myofibroblast differentiation, and the production of extracellular matrix in IPF development as well. The expression of candidate genes acting upstream and downstream of mTORC1, as well as Vegf and low-density lipoprotein receptor related protein 1(Lrp1), was assessed using specific primers and quantitative polymerase chain reaction (qPCR) within the lung tissues of bleomycin (BLM)-induced IPF mouse models. Lung fibrosis was evaluated by histological examinations and hydroxyproline colorimetric assay. BLM-exposed mice developed lung injuries characterized by inflammatory manifestations and fibrotic features, along with higher levels of collagen and hydroxyproline. Gene expression analyses indicated a significant elevation of regulatory associated protein of mTOR (Raptor), Ras homolog enriched in brain (Rheb), S6 kinase 1, and Eukaryotic translation initiation factor 4E-binding protein 1 (4Ebp1), as well as a significant reduction of Vegfa, Tuberous sclerosis complex (Tsc2), and Lrp1; no changes were observed in the Tsc1 mRNA level. Our findings support the elevation of S6K1 and 4EBP1 in response to the TSC/RHEB/mTORC1 axis, which profoundly encourages the development and establishment of IPF and cancer. In addition, this study suggests a possible preventive role for VEGF-A and LRP1 in the development of IPF.
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Affiliation(s)
- Marjan Taherian
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran AND Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
| | - Paria Bayati
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran AND Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
| | - Mohammad-Ali Assarehzadegan
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran AND Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
| | - Mansoureh Soleimani
- The Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Hadi Poormoghim
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran AND Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
| | - Nazanin Mojtabavi
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran AND Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
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4
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Yang J, Zhang W, Lai E, Liu W, Lai P, Zou Z, Wang W, Bai X. Deletion of Rheb1 in Osteocytes Leads to Osteopenia Characterized by Reduced Bone Formation and Enhanced Bone Resorption. DNA Cell Biol 2022; 41:683-690. [PMID: 35687365 DOI: 10.1089/dna.2021.0874] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ras homologue enriched in brain 1 (Rheb1), an upstream activator of the mechanistic target of rapamycin complex 1 (mTORC1), is known to modulate various cellular processes. However, its impact on bone metabolism in vivo remains unknown. The study aimed at understanding the role of Rheb1 on bone homeostasis. We measured the serum parameters and performed histomorphometry, quantitative real-time polymerase chain reaction, and Western blotting, along with the generation of mouse gene knockout (KO) model, and conducted a microcomputed tomography analysis and tartrate-resistant acid phosphatase staining, to delineate the impacts of Rheb1 on bone homeostasis. In the Rheb1 KO mice, the results showed that Rheb1 KO caused significant damage to the bone microarchitecture, indicating that mTORC1 activity was essential for the regulation of bone homeostasis. Specifically, suppressed mineralization activity in primary osteoblasts and a decreased osteoblast number were observed in the Rheb1 KO mice, demonstrating that loss of Rheb1 led to impaired osteoblastic differentiation. Furthermore, the higher apoptotic ratio in Rheb1-null osteocytes could promote Tnfsf11 expression and lead to an increase in osteoclasts, indicating increased bone resorption activity in the KO mice. The findings confirmed that Rheb1 deletion in osteoblasts/osteocytes led to osteopenia due to impaired bone formation and enhanced bone resorption.
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Affiliation(s)
- Jun Yang
- Department of Hepatobiliary and Pancreatic Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde), Foshan, China.,State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Wuju Zhang
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Eryong Lai
- Oncology Department of the Fifth Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Wen Liu
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Pinglin Lai
- Academy of Orthopedics, Guangdong Province, Guangdong Provincial Key Laboratory of Bone and Joint Degeneration Diseases, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Zhipeng Zou
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Weidong Wang
- Department of Hepatobiliary and Pancreatic Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde), Foshan, China
| | - Xiaochun Bai
- Department of Hepatobiliary and Pancreatic Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde), Foshan, China.,State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Academy of Orthopedics, Guangdong Province, Guangdong Provincial Key Laboratory of Bone and Joint Degeneration Diseases, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
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5
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Grad M, Nir A, Levy G, Trangle SS, Shapira G, Shomron N, Assaf Y, Barak B. Altered White Matter and microRNA Expression in a Murine Model Related to Williams Syndrome Suggests That miR-34b/c Affects Brain Development via Ptpru and Dcx Modulation. Cells 2022; 11:cells11010158. [PMID: 35011720 PMCID: PMC8750756 DOI: 10.3390/cells11010158] [Citation(s) in RCA: 6] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/15/2021] [Accepted: 12/28/2021] [Indexed: 11/16/2022] Open
Abstract
Williams syndrome (WS) is a multisystem neurodevelopmental disorder caused by a de novo hemizygous deletion of ~26 genes from chromosome 7q11.23, among them the general transcription factor II-I (GTF2I). By studying a novel murine model for the hypersociability phenotype associated with WS, we previously revealed surprising aberrations in myelination and cell differentiation properties in the cortices of mutant mice compared to controls. These mutant mice had selective deletion of Gtf2i in the excitatory neurons of the forebrain. Here, we applied diffusion magnetic resonance imaging and fiber tracking, which showed a reduction in the number of streamlines in limbic outputs such as the fimbria/fornix fibers and the stria terminalis, as well as the corpus callosum of these mutant mice compared to controls. Furthermore, we utilized next-generation sequencing (NGS) analysis of cortical small RNAs' expression (RNA-Seq) levels to identify altered expression of microRNAs (miRNAs), including two from the miR-34 cluster, known to be involved in prominent processes in the developing nervous system. Luciferase reporter assay confirmed the direct binding of miR-34c-5p to the 3'UTR of PTPRU-a gene involved in neural development that was elevated in the cortices of mutant mice relative to controls. Moreover, we found an age-dependent variation in the expression levels of doublecortin (Dcx)-a verified miR-34 target. Thus, we demonstrate the substantial effect a single gene deletion can exert on miRNA regulation and brain structure, and advance our understanding and, hopefully, treatment of WS.
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Affiliation(s)
- Meitar Grad
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (M.G.); (A.N.); (G.L.); (N.S.); (Y.A.)
| | - Ariel Nir
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (M.G.); (A.N.); (G.L.); (N.S.); (Y.A.)
| | - Gilad Levy
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (M.G.); (A.N.); (G.L.); (N.S.); (Y.A.)
| | - Sari Schokoroy Trangle
- Faculty of Social Sciences, School of Psychological Sciences, Tel Aviv University, Tel Aviv 6997801, Israel;
| | - Guy Shapira
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel;
- Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Noam Shomron
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (M.G.); (A.N.); (G.L.); (N.S.); (Y.A.)
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel;
- Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Yaniv Assaf
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (M.G.); (A.N.); (G.L.); (N.S.); (Y.A.)
- Faculty of Life Sciences, School of Neurobiology, Biochemistry & Biophysics, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Boaz Barak
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (M.G.); (A.N.); (G.L.); (N.S.); (Y.A.)
- Faculty of Social Sciences, School of Psychological Sciences, Tel Aviv University, Tel Aviv 6997801, Israel;
- Correspondence:
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6
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Yang Y, Cai Z, Pan Z, Liu F, Li D, Ji Y, Zhong J, Luo H, Hu S, Song L, Yu S, Li T, Li J, Ma X, Zhang W, Zhou Z, Liu F, Zhang J. Rheb1 promotes glucose-stimulated insulin secretion in human and mouse β-cells by upregulating GLUT expression. Metabolism 2021; 123:154863. [PMID: 34375645 DOI: 10.1016/j.metabol.2021.154863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 06/01/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 12/20/2022]
Abstract
Reduced β-cell mass and impaired β-cell function are primary causes of all types of diabetes. However, the intrinsic molecular mechanism that regulates β-cell growth and function remains elusive. Here, we demonstrate that the small GTPase Rheb1 is a critical regulator of glucose-stimulated insulin secretion (GSIS) in β-cells. Rheb1 was highly expressed in mouse and human islets. In addition, β-cell-specific knockout of Rheb1 reduced the β-cell size and mass by suppressing β-cell proliferation and increasing β-cell apoptosis. However, tamoxifen-induced deletion of Rheb1 in β-cells had no significant effect on β-cell mass and size but significantly impaired GSIS. Rheb1 facilitates GSIS in human or mouse islets by upregulating GLUT1 or GLUT2 expression, respectively, in a mTORC1 signaling pathway-dependent manner. Our findings reveal a critical role of Rheb1 in regulating GSIS in β-cells and identified a new target for the therapeutic treatment of diabetes mellitus.
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Affiliation(s)
- Yan Yang
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Zixin Cai
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Zhenhong Pan
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Fen Liu
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Dandan Li
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Yujiao Ji
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Jiaxin Zhong
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Hairong Luo
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Shanbiao Hu
- Department of Urological Organ Transplantation, the Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China
| | - Lei Song
- Department of Urological Organ Transplantation, the Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China
| | - Shaojie Yu
- Department of Urological Organ Transplantation, the Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China
| | - Ting Li
- Department of Liver Organ Transplantation, the Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China
| | - Jiequn Li
- Department of Liver Organ Transplantation, the Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China
| | - Xianhua Ma
- Department of Pathophysiology, Naval Medical University, Shanghai 200433, China
| | - Weiping Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai 200433, China
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Feng Liu
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Jingjing Zhang
- National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China.
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7
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Tian Q, Gromov P, Clement JH, Wang Y, Riemann M, Weih F, Sun XX, Dai MS, Fedorov LM. RHEB1 insufficiency in aged male mice is associated with stress-induced seizures. GeroScience 2017; 39:557-70. [PMID: 28891034 DOI: 10.1007/s11357-017-9997-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 08/24/2017] [Indexed: 02/06/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR), a protein kinase, is a central regulator of mammalian metabolism and physiology. Protein mTOR complex 1 (mTORC1) functions as a major sensor for the nutrient, energy, and redox state of a cell and is activated by ras homolog enriched in brain (RHEB1), a GTP-binding protein. Increased activation of mTORC1 pathway has been associated with developmental abnormalities, certain form of epilepsy (tuberous sclerosis), and cancer. Clinically, those mTOR-related disorders are treated with the mTOR inhibitor rapamycin and its rapalogs. Because the effects of chronic interference with mTOR signaling in the aged brain are yet unknown, we used a genetic strategy to interfere with mTORC1 signaling selectively by introducing mutations of Rheb1 into the mouse. We created conventional knockout (Rheb1 +/- ) and gene trap (Rheb1 Δ/+ ) mutant mouse lines. Rheb1-insufficient mice with different combinations of mutant alleles were monitored over a time span of 2 years. The mice did not show any behavioral/neurological changes during the first 18 months of age. However, after aging (> 18 months of age), both the Rheb1 +/- and Rheb1 Δ /- hybrid males developed rare stress-induced seizures, whereas Rheb1 +/- and Rheb1 Δ /- females and Rheb1 Δ/+ and Rheb1 Δ/Δ mice of both genders did not show any abnormality. Our findings suggest that chronic intervention with mTORC1 signaling in the aged brain might be associated with major adverse events.
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Jiang NW, Wang DJ, Xie YJ, Zhou L, Su LD, Li H, Wang QW, Shen Y. Downregulation of Glutamate Transporter EAAT4 by Conditional Knockout of Rheb1 in Cerebellar Purkinje Cells. Cerebellum 2017; 15:314-21. [PMID: 26194056 DOI: 10.1007/s12311-015-0701-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Excitatory amino acid transporter 4 (EAAT4) is believed to be critical to the synaptic activity of cerebellar Purkinje cells by limiting extracellular glutamate concentrations and facilitating the induction of long-term depression. However, the modulation of EAAT4 expression has not been elucidated. It has been shown that Ras homolog enriched in brain (Rheb)/mammalian target of rapamycin (mTOR) signaling plays essential roles in the regulation of protein translation, cell size, and cell growth. In addition, we previously found that a cascade including mTOR suppression and Akt activation induces increased expression of EAAT2 in astrocytes. In the present work, we explored whether Rheb/mTOR signaling is involved in the regulation of EAAT4 expression using conditional Rheb1 knockout mice. Our results demonstrated that Rheb1 deficiency resulted in the downregulation of EAAT4 expression, as well as decreased activity of mTOR and increased activity of Akt. The downregulation of EAAT4 was also confirmed by reduced EAAT4 currents and slowed kinetics of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor-mediated currents. On the other hand, conditional knockout of Rheb1 did not alter the morphology of Purkinje cell layer and the number of Purkinje cells. Overall, our findings suggest that small GTPase Rheb1 is a modulator in the expression of EAAT4 in Purkinje cells.
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Affiliation(s)
- Nan-Wei Jiang
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, Department of Physiology and Pharmacology, Ningbo University School of Medicine, Ningbo, 315211, China
| | - De-Juan Wang
- Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China
| | - Ya-Jun Xie
- Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China
| | - Liang Zhou
- Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China
| | - Li-Da Su
- Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China.,Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Huashun Li
- Shenzhen Key laboratory for Molecular Biology of Neural Development, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Qin-Wen Wang
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, Department of Physiology and Pharmacology, Ningbo University School of Medicine, Ningbo, 315211, China.
| | - Ying Shen
- Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China.
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9
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Gao Y, Gao J, Li M, Zheng Y, Wang Y, Zhang H, Wang W, Chu Y, Wang X, Xu M, Cheng T, Ju Z, Yuan W. Rheb1 promotes tumor progression through mTORC1 in MLL-AF9-initiated murine acute myeloid leukemia. J Hematol Oncol 2016; 9:36. [PMID: 27071307 PMCID: PMC4830070 DOI: 10.1186/s13045-016-0264-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 04/03/2016] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The constitutive hyper-activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathways has frequently been associated with acute myeloid leukemia (AML). While many inhibitors targeting these pathways have been developed, the anti-leukemic effect was not as robust as expected. As part of the molecular link between PI3K/Akt and mTOR kinase, the role of Rheb1 in AML remains unexplored. Our study aims to explore the role of Rheb1 in AML and estimate whether Rheb1 could be a potential target of AML treatment. METHODS The expressions of Rheb1 and other indicated genes were analyzed using real-time PCR. AML mouse model was established by retrovirus transduction. Leukemia cell properties and related signaling pathways were dissected by in vitro and in vivo studies. The transcriptional changes were analyzed via gene chip analysis. Molecular reagents including mTOR inhibitor and mTOR activator were used to evaluate the function of related signaling pathway in the mouse model. RESULTS We observed that Rheb1 is overexpressed in AML patients and the change of Rheb1 level in AML patients is associated with their median survival. Using a Rheb1-deficient MLL-AF9 murine AML model, we revealed that Rheb1 deletion prolonged the survival of AML mice by weakening LSC function. In addition, Rheb1 deletion arrested cell cycle progression and enhanced apoptosis of AML cells. Furthermore, while Rheb1 deletion reduced mTORC1 activity in AML cells, additional rapamycin treatment further decreased mTORC1 activity and increased the apoptosis of Rheb1 (Δ/Δ) AML cells. The mTOR activator 3BDO partially rescued mTORC1 signaling and inhibited apoptosis in Rheb1 (Δ/Δ) AML cells. CONCLUSIONS Our data suggest that Rheb1 promotes AML progression through mTORC1 signaling pathway and combinational drug treatments targeting Rheb1 and mTOR might have a better therapeutic effect on leukemia.
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Affiliation(s)
- Yanan Gao
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Juan Gao
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Minghao Li
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Yawei Zheng
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Yajie Wang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Hongyan Zhang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Weili Wang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Yajing Chu
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Xiaomin Wang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China.
| | - Mingjiang Xu
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, USA
| | - Tao Cheng
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China
| | - Zhenyu Ju
- Institute of Aging, Hangzhou Normal University, Hangzhou, 310036, China
| | - Weiping Yuan
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Center for Stem Cell Medicine, CAMS & PUMC, Beijing, China.
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Kang E, Kim JY, Liu CY, Xiao B, Chen PY, Christian KM, Worley PF, Song H, Ming GL. Rheb1 mediates DISC1-dependent regulation of new neuron development in the adult hippocampus. Neurogenesis (Austin) 2015; 2:e1081715. [PMID: 27606328 PMCID: PMC4973590 DOI: 10.1080/23262133.2015.1081715] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/01/2015] [Accepted: 08/04/2015] [Indexed: 02/05/2023]
Abstract
A large number of susceptibility genes have been implicated in psychiatric disorders with a developmental origin, yet their biological roles and signaling mechanisms in neurodevelopment are largely unknown. Disrupted-In-Schizophrenia 1 (DISC1), a susceptibility gene for several major psychiatric disorders, regulates the development of newborn neurons in the adult hippocampus. Systemic pharmacological inhibition of mTOR signaling with rapamycin has been shown to rescue DISC1 deficiency-induced neurodevelopmental defects, as well as cognitive and affective deficits. Whether mTOR signaling plays a cell-autonomous and/or non-cell-autonomous role in DISC1-dependent regulation of neuronal development is not clear. Here we provide genetic evidence that hyper-activation of mTOR activator Rheb1 (Ras homolog enriched in brain 1) in newborn neurons recapitulates DISC1 deficiency-induced neurodevelopmental defects, including neuronal morphogenesis and migration. We further show that genetic deletion of Rheb1 rescues those defects in a cell-autonomous fashion in developing newborn neurons in the adult hippocampus. Our genetic and functional studies demonstrate that Rheb1 acts as a key mediator of DISC1-dependent regulation of mTOR signaling and neuronal development during adult hippocampal neurogenesis.
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Affiliation(s)
- Eunchai Kang
- Institute for Cell Engineering; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; These authors contributed equally to this work
| | - Ju Young Kim
- Institute for Cell Engineering; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; These authors contributed equally to this work
| | - Cindy Y Liu
- Institute for Cell Engineering; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Bo Xiao
- The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; The State Key Laboratory of Biotherapy; West China Hospital; Sichuan University; Chengdu P.R. China
| | - Po Yu Chen
- Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine ; Baltimore, MD USA
| | - Kimberly M Christian
- Institute for Cell Engineering; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Paul F Worley
- Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Hongjun Song
- Institute for Cell Engineering; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Guo-Li Ming
- Institute for Cell Engineering; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Neurology; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; The Solomon H. Snyder Department of Neuroscience; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA; Graduate Program in Cellular and Molecular Medicine; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine; Baltimore, MD USA; Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA
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Zou Y, Jiang W, Wang J, Li Z, Zhang J, Bu J, Zou J, Zhou L, Yu S, Cui Y, Yang W, Luo L, Lu QR, Liu Y, Chen M, Worley PF, Xiao B. Oligodendrocyte precursor cell-intrinsic effect of Rheb1 controls differentiation and mediates mTORC1-dependent myelination in brain. J Neurosci 2014; 34:15764-78. [PMID: 25411504 DOI: 10.1523/JNEUROSCI.2267-14.2014] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Rheb1 is an immediate early gene that functions to activate mammalian target of rapamycin (mTor) selectively in complex 1 (mTORC1). We have demonstrated previously that Rheb1 is essential for myelination in the CNS using a Nestin-Cre driver line that deletes Rheb1 in all neural cell lineages, and recent studies using oligodendrocyte-specific CNP-Cre have suggested a preferential role for mTORC1 is myelination in the spinal cord. Here, we examine the role of Rheb1/mTORC1 in mouse oligodendrocyte lineage using separate Cre drivers for oligodendrocyte progenitor cells (OPCs) including Olig1-Cre and Olig2-Cre as well as differentiated and mature oligodendrocytes including CNP-Cre and Tmem10-Cre. Deletion of Rheb1 in OPCs impairs their differentiation to mature oligodendrocytes. This is accompanied by reduced OPC cell-cycle exit suggesting a requirement for Rheb1 in OPC differentiation. The effect of Rheb1 on OPC differentiation is mediated by mTor since Olig1-Cre deletion of mTor phenocopies Olig1-Cre Rheb1 deletion. Deletion of Rheb1 in mature oligodendrocytes, in contrast, does not disrupt developmental myelination or myelin maintenance. Loss of Rheb1 in OPCs or neural progenitors does not affect astrocyte formation in gray and white matter, as indicated by the pan-astrocyte marker Aldh1L1. We conclude that OPC-intrinsic mTORC1 activity mediated by Rheb1 is critical for differentiation of OPCs to mature oligodendrocytes, but that mature oligodendrocytes do not require Rheb1 to make myelin or maintain it in the adult brain. These studies reveal mechanisms that may be relevant for both developmental myelination and impaired remyelination in myelin disease.
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Wu H, Han ZL, Cao YS, Lin S, Li X. Cardiac ablation of Rheb1 reduces sodium currents in infant mice. Int J Clin Exp Med 2014; 7:947-954. [PMID: 24955166 PMCID: PMC4057845] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 03/12/2014] [Indexed: 06/03/2023]
Abstract
OBJECTIVE The Ras homolog enriched in brain gene (Rheb) is a center player within the insulin/Rheb/Mammalian Target of Rapamycin (mTOR) pathway, and plays a critical role in regulating cellular growth. Rheb-/- embryos have been reported to die around midgestation, due to the defects of the development of the cardiovascular system. Recent studies from ours and another group consistently showed that Rheb1 was indispensable for the cardiac hypertrophic growth after early postnatal period. Besides that, we also found that Rheb1 a-MHC-Cre (cKO) mice exhibited ventricular tachycardia. However, the precise mechanism by which Rheb1 knockout causes ventricular arrhythmia in these mice is still unclear. METHODS Mouse cardiomyocytes were isolated using 10 days suckling Rheb1 cKO and wide type mice using Collagenase Type II. Sodium currents and L-type calcium currents were recorded using the whole-cell patch clamping technique. RESULTS The sodium current density of ventricular cardiomyocytes from Rheb1 cKO mice was decreased by about 60%. Significant left shift but no slope altered was observed in activation curve with V1/2 values of -35.35 ± 1.12 mV for Rheb1 cKO group and -40.72 ± 1.18 mV for the controls. In addition, the area of window current, which refers the overlap of normalized activation and inactivation, was larger in Rheb1 cKO mice. Moreover, the sodium current, in general, was recovered much slower in Rheb1 cKO mice than that of the controls. However, L-type calcium currents were preserved in Rheb1 cKO mice. CONCLUSION Sodium currents are decreased in Rheb1 cKO mice, which might be responsible for the phenotype of arrhythima in Rheb1 cKO mice. Understanding the molecular composition of sodium ion channel complexes in the heart of these Rheb1 cKO mice will be critical to develop innovative and effective therapies for the treatment of cardiac arrhythmia.
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Affiliation(s)
- Hang Wu
- Department of Cardiology, First Affiliated Hospital of Nanjing Medical University Nanjing 210029, China ; Linhu Ward, Maanshan Municipal People's Hospital Maanshan 243021, China
| | - Zhong-Lin Han
- Department of Cardiology, First Affiliated Hospital of Nanjing Medical University Nanjing 210029, China
| | - Yun-Shan Cao
- Department of Cardiology, First Affiliated Hospital of Nanjing Medical University Nanjing 210029, China ; MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University Nanjing 210061, China
| | - Shenghui Lin
- Department of Cardiology, First Affiliated Hospital of Nanjing Medical University Nanjing 210029, China
| | - Xinli Li
- Department of Cardiology, First Affiliated Hospital of Nanjing Medical University Nanjing 210029, China
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