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Arponen M, Jalava N, Widjaja N, Ivaska KK. Glucose transporters GLUT1, GLUT3, and GLUT4 have different effects on osteoblast proliferation and metabolism. Front Physiol 2022; 13:1035516. [PMID: 36523556 PMCID: PMC9744933 DOI: 10.3389/fphys.2022.1035516] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/15/2022] [Indexed: 03/05/2024] Open
Abstract
Bone is an active tissue that undergoes constant remodeling. Bone formation requires energy and one of the energy sources of bone-forming osteoblasts is glucose, which is transported inside the cells via glucose transporters. However, the role of class I glucose transporters in the differentiation and metabolism of osteoblasts and their precursors, bone marrow mesenchymal stromal cells (BMSCs) remains inconclusive. Our aim was to characterize the expression and contribution of main class I glucose transporters, GLUT1, GLUT3, and GLUT4, during osteoblast proliferation and differentiation. To investigate the role of each GLUT, we downregulated GLUTs with siRNA technology in primary rat BMSCs. Live-cell imaging and RNA-seq analysis was used to evaluate downstream pathways in silenced osteoblasts. Glucose transporters GLUT1, GLUT3, and GLUT4 had distinct expression patterns in osteoblasts. GLUT1 was abundant in BMSCs, but rapidly and significantly downregulated during osteoblast differentiation by up to 80% (p < 0.001). Similar downregulation was observed for GLUT4 (p < 0.001). In contrast, expression levels of GLUT3 remained stable during differentiation. Osteoblasts lacked GLUT2. Silencing of GLUT4 resulted in a significant decrease in proliferation and differentiation of preosteoblasts (p < 0.001) and several pathways related to carbohydrate metabolism and cell signaling were suppressed. However, silencing of GLUT3 resulted in increased proliferation (p < 0.001), despite suppression of several pathways involved in cellular metabolism, biosynthesis and actin organization. Silencing of GLUT1 had no effect on proliferation and less changes in the transcriptome. RNA-seq dataset further revealed that osteoblasts express also class II and III glucose transporters, except for GLUT7. In conclusion, GLUT1, -3 and -4 may all contribute to glucose uptake in differentiating osteoblasts. GLUT4 expression was clearly required for osteoblast proliferation and differentiation. GLUT1 appears to be abundant in early precursors, but stable expression of GLUT3 suggest also a role for GLUT3 in osteoblasts. Presence of other GLUT members may further contribute to fine-tuning of glucose uptake. Together, glucose uptake in osteoblast lineage appears to rely on several glucose transporters to ensure sufficient energy for new bone formation.
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Affiliation(s)
| | | | | | - Kaisa K. Ivaska
- Institute of Biomedicine, University of Turku, Turku, Finland
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Exploring the Physiological Role of Transthyretin in Glucose Metabolism in the Liver. Int J Mol Sci 2021; 22:ijms22116073. [PMID: 34199897 PMCID: PMC8200108 DOI: 10.3390/ijms22116073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/26/2021] [Accepted: 06/01/2021] [Indexed: 12/22/2022] Open
Abstract
Transthyretin (TTR), a 55 kDa evolutionarily conserved protein, presents altered levels in several conditions, including malnutrition, inflammation, diabetes, and Alzheimer’s Disease. It has been shown that TTR is involved in several functions, such as insulin release from pancreatic β-cells, recovery of blood glucose and glucagon levels of the islets of Langerhans, food intake, and body weight. Here, the role of TTR in hepatic glucose metabolism was explored by studying the levels of glucose in mice with different TTR genetic backgrounds, namely with two copies of the TTR gene, TTR+/+; with only one copy, TTR+/−; and without TTR, TTR−/−. Results showed that TTR haploinsufficiency (TTR+/−) leads to higher glucose in both plasma and in primary hepatocyte culture media and lower expression of the influx glucose transporters, GLUT1, GLUT3, and GLUT4. Further, we showed that TTR haploinsufficiency decreases pyruvate kinase M type (PKM) levels in mice livers, by qRT-PCR, but it does not affect the hepatic production of the studied metabolites, as determined by 1H NMR. Finally, we demonstrated that TTR increases mitochondrial density in HepG2 cells and that TTR insufficiency triggers a higher degree of oxidative phosphorylation in the liver. Altogether, these results indicate that TTR contributes to the homeostasis of glucose by regulating the levels of glucose transporters and PKM enzyme and by protecting against mitochondrial oxidative stress.
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Marshall J, Zhou XZ, Chen G, Yang SQ, Li Y, Wang Y, Zhang ZQ, Jiang Q, Birnbaumer L, Cao C. Antidepression action of BDNF requires and is mimicked by Gαi1/3 expression in the hippocampus. Proc Natl Acad Sci U S A 2018; 115:E3549-E3558. [PMID: 29507199 PMCID: PMC5899481 DOI: 10.1073/pnas.1722493115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Stress-related alterations in brain-derived neurotrophic factor (BDNF) expression, a neurotrophin that plays a key role in synaptic plasticity, are believed to contribute to the pathophysiology of depression. Here, we show that in a chronic mild stress (CMS) model of depression the Gαi1 and Gαi3 subunits of heterotrimeric G proteins are down-regulated in the hippocampus, a key limbic structure associated with major depressive disorder. We provide evidence that Gαi1 and Gαi3 (Gαi1/3) are required for the activation of TrkB downstream signaling pathways. In mouse embryonic fibroblasts (MEFs) and CNS neurons, Gαi1/3 knockdown inhibited BDNF-induced tropomyosin-related kinase B (TrkB) endocytosis, adaptor protein activation, and Akt-mTORC1 and Erk-MAPK signaling. Functional studies show that Gαi1 and Gαi3 knockdown decreases the number of dendrites and dendritic spines in hippocampal neurons. In vivo, hippocampal Gαi1/3 knockdown after bilateral microinjection of lentiviral constructs containing Gαi1 and Gαi3 shRNA elicited depressive behaviors. Critically, exogenous expression of Gαi3 in the hippocampus reversed depressive behaviors in CMS mice. Similar results were observed in Gαi1/Gαi3 double-knockout mice, which exhibited severe depressive behaviors. These results demonstrate that heterotrimeric Gαi1 and Gαi3 proteins are essential for TrkB signaling and that disruption of Gαi1 or Gαi3 function could contribute to depressive behaviors.
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MESH Headings
- Animals
- Brain-Derived Neurotrophic Factor/metabolism
- Dendrites/metabolism
- Dendrites/pathology
- Dendritic Spines/metabolism
- Dendritic Spines/pathology
- Depression/metabolism
- Depression/pathology
- Depressive Disorder, Major/metabolism
- Depressive Disorder, Major/pathology
- Down-Regulation
- Female
- GTP-Binding Protein alpha Subunit, Gi2/biosynthesis
- GTP-Binding Protein alpha Subunit, Gi2/genetics
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/biosynthesis
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Hippocampus/metabolism
- Mice
- Mice, Knockout
- Neurons/metabolism
- Neurons/pathology
- Signal Transduction/drug effects
- Stress, Physiological/physiology
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Affiliation(s)
- John Marshall
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912;
| | - Xiao-Zhong Zhou
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 Jiangsu, China
| | - Gang Chen
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, 215006 Jiangsu, China
| | - Su-Qing Yang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Ya Li
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Yin Wang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Zhi-Qing Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Qin Jiang
- The Fourth School of Clinical Medicine, The Affiliated Eye Hospital, Nanjing Medical University, 210029 Nanjing, China
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709;
- School of Medical Sciences, Institute of Biomedical Research, Catholic University of Argentina, C1107AAZ Buenos Aires, Argentina
| | - Cong Cao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China;
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
- The Fourth School of Clinical Medicine, The Affiliated Eye Hospital, Nanjing Medical University, 210029 Nanjing, China
- North District, The Municipal Hospital of Suzhou, Suzhou 215001, China
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Chen MB, Liu YY, Xing ZY, Zhang ZQ, Jiang Q, Lu PH, Cao C. Itraconazole-Induced Inhibition on Human Esophageal Cancer Cell Growth Requires AMPK Activation. Mol Cancer Ther 2018; 17:1229-1239. [PMID: 29592879 DOI: 10.1158/1535-7163.mct-17-1094] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/11/2018] [Accepted: 03/22/2018] [Indexed: 11/16/2022]
Abstract
We here evaluated the antiesophageal cancer cell activity by the antifungal drug itraconazole. Our results show that μg/mL concentrations of itraconazole potently inhibited survival and proliferation of established (TE-1 and Eca-109) and primary human esophageal cancer cells. Itraconazole activated AMPK signaling, which was required for subsequent esophageal cancer cell death. Pharmacologic AMPK inhibition, AMPKα1 shRNA, or dominant negative mutation (T172A) almost completely abolished itraconazole-induced cytotoxicity against esophageal cancer cells. Significantly, itraconazole induced AMPK-dependent autophagic cell death (but not apoptosis) in esophageal cancer cells. Furthermore, AMPK activation by itraconazole induced multiple receptor tyrosine kinases (RTKs: EGFR, PDGFRα, and PDGFRβ), lysosomal translocation, and degradation to inhibit downstream Akt activation. In vivo, itraconazole oral gavage potently inhibited Eca-109 tumor growth in SCID mice. It was yet ineffective against AMPKα1 shRNA-expressing Eca-109 tumors. The in vivo growth of the primary human esophageal cancer cells was also significantly inhibited by itraconazole administration. AMPK activation, RTK degradation, and Akt inhibition were observed in itraconazole-treated tumors. Together, itraconazole inhibits esophageal cancer cell growth via activating AMPK signaling. Mol Cancer Ther; 17(6); 1229-39. ©2018 AACR.
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Affiliation(s)
- Min-Bin Chen
- Department of Radiotherapy & Oncology, Kunshan First People's Hospital Affiliated to Jiangsu University, Kunshan, China
| | - Yuan-Yuan Liu
- Clinical Research and Lab Center, Kunshan First People's Hospital Affiliated to Jiangsu University, Kunshan, China
| | - Zhao-Yu Xing
- The Department of Urology, the Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Zhi-Qing Zhang
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Qin Jiang
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing, China.
| | - Pei-Hua Lu
- Department of Medical Oncology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, China.
| | - Cong Cao
- Institute of Neuroscience, Soochow University, Suzhou, China. .,The Affiliated Eye Hospital of Nanjing Medical University, Nanjing, China.,The Municipal Hospital of Suzhou, North District, Suzhou, China
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