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Xu K, Zhang L, Wang T, Yu T, Zhao X, Zhang Y. Transcriptomics reveals dynamic changes in the "gene profiles" of rat supraspinatus tendon at three different time points after diabetes induction. BMC Med Genomics 2024; 17:122. [PMID: 38711057 DOI: 10.1186/s12920-024-01899-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/30/2024] [Indexed: 05/08/2024] Open
Abstract
OBJECTIVE There is increasing evidence that type 2 diabetes mellitus (T2DM) is an independent risk factor for the occur of tendinopathy. Therefore, this study is the first to explore the dynamic changes of the "gene profile" of supraspinatus tendon in rats at different time points after T2DM induction through transcriptomics, providing potential molecular markers for exploring the pathogenesis of diabetic tendinopathy. METHODS A total of 40 Sprague-Dawley rats were randomly divided into normal (NG, n = 10) and T2DM groups (T2DM, n = 30) and subdivided into three groups according to the duration of diabetes: T2DM-4w, T2DM-8w, and T2DM-12w groups; the duration was calculated from the time point of T2DM rat model establishment. The three comparison groups were set up in this study, T2DM-4w group vs. NG, T2DM-8w group vs. NG, and T2DM-12w group vs. NG. Differentially expressed genes (DEGs) in 3 comparison groups were screened. The intersection of the three comparison groups' DEGs was defined as key genes that changed consistently in the supraspinatus tendon after diabetes induction. Cluster analysis, gene ontology (GO) functional annotation analysis and Kyoto encyclopedia of genes and genomes (KEGG) functional annotation and enrichment analysis were performed for DEGs. RESULTS T2DM-4w group vs. NG, T2DM-8w group vs. NG, and T2DM-12w group vs. NG detected 519 (251 up-regulated and 268 down-regulated), 459 (342 up-regulated and 117 down-regulated) and 328 (255 up-regulated and 73 down-regulated) DEGs, respectively. 103 key genes of sustained changes in the supraspinatus tendon following induction of diabetes, which are the first identified biomarkers of the supraspinatus tendon as it progresses through the course of diabetes.The GO analysis results showed that the most significant enrichment in biological processes was calcium ion transmembrane import into cytosol (3 DEGs). The most significant enrichment in cellular component was extracellular matrix (9 DEGs). The most significant enrichment in molecular function was glutamate-gated calcium ion channel activity (3 DEGs). The results of KEGG pathway enrichment analysis showed that there were 17 major pathways (p < 0.05) that diabetes affected supratinusculus tendinopathy, including cAMP signaling pathway and Calcium signaling pathway. CONCLUSIONS Transcriptomics reveals dynamic changes in the"gene profiles"of rat supraspinatus tendon at three different time points after diabetes induction. The 103 DEGs identified in this study may provide potential molecular markers for exploring the pathogenesis of diabetic tendinopathy, and the 17 major pathways enriched in KEGG may provide new ideas for exploring the pathogenesis of diabetic tendinopathy.
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Affiliation(s)
- Kuishuai Xu
- Department of Sports Medicine, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China
| | - Liang Zhang
- Department of Abdominal Ultrasound, Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China
| | - Tianrui Wang
- Department of Traumatology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China
| | - Tengbo Yu
- Department of Orthopedic Surgery, Qingdao Municipal Hospital, Qingdao, 266000, Shandong, China
| | - Xia Zhao
- Department of Sports Medicine, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China.
| | - Yingze Zhang
- Department of Sports Medicine, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China.
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2
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Oh M, Batty S, Banerjee N, Kim TH. High extracellular glucose promotes cell motility by modulating cell deformability and contractility via the cAMP-RhoA-ROCK axis in human breast cancer cells. Mol Biol Cell 2023; 34:ar79. [PMID: 37195739 PMCID: PMC10398875 DOI: 10.1091/mbc.e22-12-0560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/18/2023] [Accepted: 05/08/2023] [Indexed: 05/18/2023] Open
Abstract
The mechanical properties, or mechanotypes, of cells are largely determined by their deformability and contractility. The ability of cancer cells to deform and generate contractile force is critical in multiple steps of metastasis. Identifying soluble cues that regulate cancer cell mechanotypes and understanding the underlying molecular mechanisms regulating these cellular mechanotypes could provide novel therapeutic targets to prevent metastasis. Although a strong correlation between high glucose level and cancer metastasis has been demonstrated, the causality has not been elucidated, and the underlying molecular mechanisms remain largely unknown. In this study, using novel high-throughput mechanotyping assays, we show that human breast cancer cells become less deformable and more contractile with increased extracellular glucose levels (>5 mM). These altered cell mechanotypes are due to increased F-actin rearrangement and nonmuscle myosin II (NMII) activity. We identify the cAMP-RhoA-ROCK-NMII axis as playing a major role in regulating cell mechanotypes at high extracellular glucose levels, whereas calcium and myosin light-chain kinase (MLCK) are not required. The altered mechanotypes are also associated with increased cell migration and invasion. Our study identifies key components in breast cancer cells that convert high extracellular glucose levels into changes in cellular mechanotype and behavior relevant in cancer metastasis.
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Affiliation(s)
- Mijung Oh
- Department of Pathology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Skylar Batty
- Undergraduate Pipeline Network Summer Research Program, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | - Nayan Banerjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, West Bengal, India
| | - Tae-Hyung Kim
- Department of Pathology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM 87131
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3
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Utilizing the Off-Target Effects of T1R3 Antagonist Lactisole to Enhance Nitric Oxide Production in Basal Airway Epithelial Cells. Nutrients 2023; 15:nu15030517. [PMID: 36771227 PMCID: PMC9919013 DOI: 10.3390/nu15030517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
Human airway sweet (T1R2 + T1R3), umami (T1R1 + T1R3), and bitter taste receptors (T2Rs) are critical components of the innate immune system, acting as sensors to monitor pathogenic growth. T2Rs detect bacterial products or bitter compounds to drive nitric oxide (NO) production in both healthy and diseased epithelial cell models. The NO enhances ciliary beating and also directly kills pathogens. Both sweet and umami receptors have been characterized to repress bitter taste receptor signaling in healthy and disease models. We hypothesized that the sweet/umami T1R3 antagonist lactisole may be used to alleviate bitter taste receptor repression in airway basal epithelial cells and enhance NO production. Here, we show that lactisole activates cAMP generation, though this occurs through a pathway independent of T1R3. This cAMP most likely signals through EPAC to increase ER Ca2+ efflux. Stimulation with denatonium benzoate, a bitter taste receptor agonist which activates largely nuclear and mitochondrial Ca2+ responses, resulted in a dramatically increased cytosolic Ca2+ response in cells treated with lactisole. This cytosolic Ca2+ signaling activated NO production in the presence of lactisole. Thus, lactisole may be useful coupled with bitter compounds as a therapeutic nasal rinse or spray to enhance beneficial antibacterial NO production in patients suffering from chronic inflammatory diseases such as chronic rhinosinusitis.
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Saito D, Nakagawa Y, Sato T, Fukunaka A, Pereye OB, Maruyama N, Watada H, Fujitani Y. Establishment of an enzyme-linked immunosorbent assay for mouse pancreatic polypeptide clarifies the regulatory mechanism of its secretion from pancreatic γ cells. PLoS One 2022; 17:e0269958. [PMID: 35976945 PMCID: PMC9385059 DOI: 10.1371/journal.pone.0269958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022] Open
Abstract
Pancreatic polypeptide (PP), secreted from γ cells of the islets of Langerhans, is a 36 amino-acid peptide encoded by the Ppy gene. Although previous studies have reported that PP causes a decrease in appetite, the molecular mechanism that regulates PP secretion has not been fully elucidated. Lack of understanding of the regulatory mechanism of PP secretion may be partially owing to the lack of assay systems that can specifically detect PP. We recently developed the mouse monoclonal antibody 23-2D3 that specifically recognizes PP. In the present study, we developed a sandwich enzyme-linked immunosorbent assay for the measurement of mouse PP, and directly monitored intracellular Ca2+ concentrations in Ppy-expressing cells from a newly developed reporter mouse. Using these systems, we identified agonists, such as carbachol and glucose-dependent insulinotropic polypeptide (GIP), which stimulate PP secretion. We further demonstrated that, unlike the case of GIP-induced insulin secretion from β cells, there is a unique mechanism by which PP secretion is triggered by an increase in intracellular Ca2+ concentrations via voltage-dependent calcium channels even in low-glucose conditions.
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Affiliation(s)
- Daisuke Saito
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
- Department of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuko Nakagawa
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Takashi Sato
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Ayako Fukunaka
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Ofejiro Blessing Pereye
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | | | - Hirotaka Watada
- Department of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yoshio Fujitani
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
- * E-mail:
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Wang Y, Liu Q, Kang SG, Huang K, Tong T. Dietary Bioactive Ingredients Modulating the cAMP Signaling in Diabetes Treatment. Nutrients 2021; 13:nu13093038. [PMID: 34578916 PMCID: PMC8467569 DOI: 10.3390/nu13093038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 02/06/2023] Open
Abstract
As the prevalence of diabetes increases progressively, research to develop new therapeutic approaches and the search for more bioactive compounds are attracting more attention. Over the past decades, studies have suggested that cyclic adenosine monophosphate (cAMP), the important intracellular second messenger, is a key regulator of metabolism and glucose homeostasis in diverse physiopathological states in multiple organs including the pancreas, liver, gut, skeletal muscle, adipose tissues, brain, and kidney. The multiple characteristics of dietary compounds and their favorable influence on diabetes pathogenesis, as well as their intersections with the cAMP signaling pathway, indicate that these compounds have a beneficial effect on the regulation of glucose homeostasis. In this review, we outline the current understanding of the diverse functions of cAMP in different organs involved in glucose homeostasis and show that a diversity of bioactive ingredients from foods activate or inhibit cAMP signaling, resulting in the improvement of the diabetic pathophysiological process. It aims to highlight the diabetes-preventative or -therapeutic potential of dietary bioactive ingredients targeting cAMP signaling.
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Affiliation(s)
- Yanan Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
| | - Qing Liu
- Jilin Green Food Engineering Research Institute, Changchun 130022, China;
| | - Seong-Gook Kang
- Department of Food Engineering, Mokpo National University, Muangun 58554, Korea;
| | - Kunlun Huang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
- Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
- Correspondence: (K.H.); (T.T.)
| | - Tao Tong
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
- Correspondence: (K.H.); (T.T.)
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Jia JD, Jiang WG, Luo X, Li RR, Zhao YC, Tian G, Li YN. Vascular endothelial growth factor B inhibits insulin secretion in MIN6 cells and reduces Ca 2+ and cyclic adenosine monophosphate levels through PI3K/AKT pathway. World J Diabetes 2021; 12:480-498. [PMID: 33889292 PMCID: PMC8040075 DOI: 10.4239/wjd.v12.i4.480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/25/2021] [Accepted: 03/08/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Type 2 diabetes (T2D) is characterized by insufficient insulin secretion caused by defective pancreatic β-cell function or insulin resistance, resulting in an increase in blood glucose. However, the mechanism involved in this lack of insulin secretion is unclear. The level of vascular endothelial growth factor B (VEGF-B) is significantly increased in T2D patients. The inactivation of VEGF-B could restore insulin sensitivity in db/db mice by reducing fatty acid accumulation. It is speculated that VEGF-B is related to pancreatic β-cell dysfunction and is an important factor affecting β-cell secretion of insulin. As an in vitro model of normal pancreatic β-cells, the MIN6 cell line can be used to analyze the mechanism of insulin secretion and related biological effects.
AIM To study the role of VEGF-B in the insulin secretion signaling pathway in MIN6 cells and explore the effect of VEGF-B on blood glucose regulation.
METHODS The MIN6 mouse pancreatic islet β-cell line was used as the model system. By administering exogenous VEGF-B protein or knocking down VEGF-B expression in MIN6 cells, we examined the effects of VEGF-B on insulin secretion, Ca2+ and cyclic adenosine monophosphate (cAMP) levels, and the insulin secretion signaling pathway.
RESULTS Exogenous VEGF-B inhibited the secretion of insulin and simultaneously reduced the levels of Ca2+ and cAMP in MIN6 cells. Exogenous VEGF-B also reduced the expression of phospholipase C gamma 1 (PLCγ1), phosphatidylinositol 3-kinase (PI3K), serine/threonine kinase (AKT), and other proteins in the insulin secretion pathway. Upon knockdown of VEGF-B, MIN6 cells exhibited increased insulin secretion and Ca2+ and cAMP levels and upregulated expression of PLCγ1, PI3K, AKT, and other proteins.
CONCLUSION VEGF-B can regulate insulin secretion by modulating the levels of Ca2+ and cAMP. VEGF-B involvement in insulin secretion is related to the expression of PLCγ1, PI3K, AKT, and other signaling proteins. These results provide theoretical support and an experimental basis for the study of VEGF-B in the pathogenesis of T2D.
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Affiliation(s)
- Jing-Dan Jia
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Wen-Guo Jiang
- Department of Pharmacy, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Xu Luo
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Rong-Rong Li
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Yu-Chi Zhao
- Department of Surgery, Yantaishan Hospital, Yantai 264001, Shandong Province, China
| | - Geng Tian
- Department of Pharmacy, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Ya-Na Li
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
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7
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Sweet taste receptors as a tool for an amplifying pathway of glucose-stimulated insulin secretion in pancreatic β cells. Pflugers Arch 2019; 471:655-657. [DOI: 10.1007/s00424-019-02271-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 03/07/2019] [Indexed: 12/25/2022]
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8
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Sanchez-Andres JV, Malaisse WJ, Kojima I. Electrophysiology of the pancreatic islet β-cell sweet taste receptor TIR3. Pflugers Arch 2018; 471:647-654. [PMID: 30552496 DOI: 10.1007/s00424-018-2237-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 12/17/2022]
Abstract
Over recent years, the presence of the sweet taste receptor TIR3 in rodent and human insulin-producing pancreatic islet β-cells was documented. The activation of this receptor by sweet-tasting sucralose mimics several biochemical and functional effects of D-glucose in the β-cells. The present study extends this analogy to the bioelectrical response of β-cells. In this respect, sucralose was inefficient in the absence of D-glucose, but induced on occasion electrical activity in mouse β-cells exposed to low non-stimulatory concentrations of the hexose and potentiated, in a concentration-related manner, the response to stimulatory concentrations of D-glucose. These data indicate that sucralose, acting as an agonist of the TIR3 receptor, exerts an excitatory effect upon pancreatic β-cell bioelectrical activity.
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Affiliation(s)
| | - Willy J Malaisse
- Department of Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Itaru Kojima
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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9
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Kojima I, Medina J, Nakagawa Y. Role of the glucose-sensing receptor in insulin secretion. Diabetes Obes Metab 2017; 19 Suppl 1:54-62. [PMID: 28880472 DOI: 10.1111/dom.13013] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/08/2017] [Accepted: 05/16/2017] [Indexed: 11/27/2022]
Abstract
Glucose is a primary stimulator of insulin secretion. It has been thought that glucose exerts its effect by a mechanism solely dependent on glucose metabolism. We show here that glucose induces rapid Ca2+ and cyclic AMP signals in β-cells. These rapid signals are independent of glucose-metabolism and are reproduced by non-metabolizable glucose analogues. These results led us to postulate that glucose activates a cell-surface receptor, namely the glucose-sensing receptor. Rapid signals induced by glucose are blocked by inhibition of a sweet taste receptor subunit T1R3 and a calcium-sensing receptor subunit CaSR. In accordance with these observations, T1R3 and CaSR form a heterodimer. In addition, a heterodimer of T1R3 and CaSR is activated by glucose. These results suggest that a heterodimer of T1R3 and CaSR is a major component of the glucose-sensing receptor. When the glucose-sensing receptor is blocked, glucose-induced insulin secretion is inhibited. Also, ATP production is significantly attenuated by the inhibition of the receptor. Conversely, stimulation of the glucose-sensing receptor by either artificial sweeteners or non-metabolizable glucose analogue increases ATP. Hence, the glucose-sensing receptor signals promote glucose metabolism. Collectively, glucose activates the cell-surface glucose-sensing receptor and promotes its own metabolism. Glucose then enters the cells and is metabolized through already activated metabolic pathways. The glucose-sensing receptor is a key molecule regulating the action of glucose in β-cells.
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MESH Headings
- Animals
- Calcium Signaling
- Cyclic AMP/metabolism
- Dimerization
- Enzyme Activation
- Gene Expression Regulation
- Glucose/metabolism
- Humans
- Insulin/metabolism
- Insulin Secretion
- Insulin-Secreting Cells/enzymology
- Insulin-Secreting Cells/metabolism
- Models, Biological
- Protein Kinase C/chemistry
- Protein Kinase C/metabolism
- Protein Multimerization
- Receptors, Calcium-Sensing/agonists
- Receptors, Calcium-Sensing/chemistry
- Receptors, Calcium-Sensing/genetics
- Receptors, Calcium-Sensing/metabolism
- Receptors, Cell Surface/agonists
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Second Messenger Systems
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Affiliation(s)
- Itaru Kojima
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Johan Medina
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Yuko Nakagawa
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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10
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Kohno D. Sweet taste receptor in the hypothalamus: a potential new player in glucose sensing in the hypothalamus. J Physiol Sci 2017; 67:459-465. [PMID: 28378265 PMCID: PMC10717116 DOI: 10.1007/s12576-017-0535-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/24/2017] [Indexed: 01/06/2023]
Abstract
The hypothalamic feeding center plays an important role in energy homeostasis. The feeding center senses the systemic energy status by detecting hormone and nutrient levels for homeostatic regulation, resulting in the control of food intake, heat production, and glucose production and uptake. The concentration of glucose is sensed by two types of glucose-sensing neurons in the feeding center: glucose-excited neurons and glucose-inhibited neurons. Previous studies have mainly focused on glucose metabolism as the mechanism underlying glucose sensing. Recent studies have indicated that receptor-mediated pathways also play a role in glucose sensing. This review describes sweet taste receptors in the hypothalamus and explores the role of sweet taste receptors in energy homeostasis.
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Affiliation(s)
- Daisuke Kohno
- Advanced Scientific Research Leaders Development Unit, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan.
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, 371-8512, Japan.
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11
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Kohno D, Koike M, Ninomiya Y, Kojima I, Kitamura T, Yada T. Sweet Taste Receptor Serves to Activate Glucose- and Leptin-Responsive Neurons in the Hypothalamic Arcuate Nucleus and Participates in Glucose Responsiveness. Front Neurosci 2016; 10:502. [PMID: 27877104 PMCID: PMC5099526 DOI: 10.3389/fnins.2016.00502] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/21/2016] [Indexed: 01/04/2023] Open
Abstract
The hypothalamic feeding center plays an important role in energy homeostasis. In the feeding center, whole-body energy signals including hormones and nutrients are sensed, processed, and integrated. As a result, food intake and energy expenditure are regulated. Two types of glucose-sensing neurons exist in the hypothalamic arcuate nucleus (ARC): glucose-excited neurons and glucose-inhibited neurons. While some molecules are known to be related to glucose sensing in the hypothalamus, the mechanisms underlying glucose sensing in the hypothalamus are not fully understood. The sweet taste receptor is a heterodimer of taste type 1 receptor 2 (T1R2) and taste type 1 receptor 3 (T1R3) and senses sweet tastes. T1R2 and T1R3 are distributed in multiple organs including the tongue, pancreas, adipose tissue, and hypothalamus. However, the role of sweet taste receptors in the ARC remains to be clarified. To examine the role of sweet taste receptors in the ARC, cytosolic Ca2+ concentration ([Ca2+]i) in isolated single ARC neurons were measured using Fura-2 fluorescent imaging. An artificial sweetener, sucralose at 10−5–10−2 M dose dependently increased [Ca2+]i in 12–16% of ARC neurons. The sucralose-induced [Ca2+]i increase was suppressed by a sweet taste receptor inhibitor, gurmarin. The sucralose-induced [Ca2+]i increase was inhibited under an extracellular Ca2+-free condition and in the presence of an L-type Ca2+ channel blocker, nitrendipine. Sucralose-responding neurons were activated by high-concentration of glucose. This response to glucose was markedly suppressed by gurmarin. More than half of sucralose-responding neurons were activated by leptin but not ghrelin. Percentages of proopiomelanocortin (POMC) neurons among sucralose-responding neurons and sweet taste receptor expressing neurons were low, suggesting that majority of sucralose-responding neurons are non-POMC neurons. These data suggest that sweet taste receptor-mediated cellular activation mainly occurs on non-POMC leptin-responding neurons and contributes to glucose responding. Endogenous sweet molecules including glucose may regulate energy homeostasis through sweet taste receptors on glucose-and leptin-responsive neurons in the ARC.
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Affiliation(s)
- Daisuke Kohno
- Advanced Scientific Research Leaders Development Unit, Gunma UniversityMaebashi, Japan; Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma UniversityMaebashi, Japan
| | - Miho Koike
- Advanced Scientific Research Leaders Development Unit, Gunma University Maebashi, Japan
| | - Yuzo Ninomiya
- Division of Sensory Physiology, Research and Development Center for Taste and Odor Sensing, Kyushu UniversityFukuoka, Japan; Monell Chemical Senses CenterPhiladelphia, PA, USA
| | - Itaru Kojima
- Department of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University Maebashi, Japan
| | - Tadahiro Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University Maebashi, Japan
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, School of Medicine, Jichi Medical University Shimotsuke, Japan
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12
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Medina J, Nakagawa Y, Nagasawa M, Fernandez A, Sakaguchi K, Kitaguchi T, Kojima I. Positive Allosteric Modulation of the Calcium-sensing Receptor by Physiological Concentrations of Glucose. J Biol Chem 2016; 291:23126-23135. [PMID: 27613866 DOI: 10.1074/jbc.m116.729863] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Indexed: 01/08/2023] Open
Abstract
The calcium-sensing receptor (CaSR) is activated by various cations, cationic compounds, and amino acids. In the present study we investigated the effect of glucose on CaSR in HEK293 cells stably expressing human CaSR (HEK-CaSR cells). When glucose concentration in the buffer was raised from 3 to 25 mm, a rapid elevation of cytoplasmic Ca2+ concentration ([Ca2+]c) was observed. This elevation was immediate and transient and was followed by a sustained decrease in [Ca2+]c The effect of glucose was detected at a concentration of 4 mm and reached its maximum at 5 mm 3-O-Methylglucose, a non-metabolizable analogue of glucose, reproduced the effect of glucose. Sucrose also induced an elevation of [Ca2+]c in HEK-CaSR cells. Similarly, sucralose was nearly as effective as glucose in inducing elevation of [Ca2+]c Glucose was not able to increase [Ca2+]c in the absence of extracellular Ca2+ The effect of glucose on [Ca2+]c was inhibited by NPS-2143, an allosteric inhibitor of CaSR. In addition, NPS-2143 also inhibited the [Ca2+]c responses to sucralose and sucrose. Glucose as well as sucralose decreased cytoplasmic cAMP concentration in HEK-CaSR cells. The reduction of cAMP induced by glucose was blocked by pertussis toxin. Likewise, sucralose reduced [cAMP]c Finally, glucose increased [Ca2+]c in PT-r parathyroid cells and in Madin-Darby canine kidney cells, both of which express endogenous CaSR. These results indicate that glucose acts as a positive allosteric modulator of CaSR.
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Affiliation(s)
- Johan Medina
- From the Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Yuko Nakagawa
- From the Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Masahiro Nagasawa
- From the Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Anny Fernandez
- From the Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Kazushige Sakaguchi
- Institute of Advanced Medicine, Wakayama Medical University, Wakayama 641-8509, Japan
| | - Tetsuya Kitaguchi
- Waseda Bioscience Research Institute in Singapore Singapore 138667, and.,Organization for University Research Initiatives, Waseda University, Tokyo 162-0041, Japan
| | - Itaru Kojima
- From the Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan,
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Li L, Ohtsu Y, Nakagawa Y, Masuda K, Kojima I. Sucralose, an activator of the glucose-sensing receptor, increases ATP by calcium-dependent and -independent mechanisms. Endocr J 2016; 63:715-25. [PMID: 27250218 DOI: 10.1507/endocrj.ej16-0217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Sucralose is an artificial sweetener and activates the glucose-sensing receptor expressed in pancreatic β-cells. Although sucralose does not enter β-cells nor acts as a substrate for glucokinase, it induces a marked elevation of intracellular ATP ([ATP]c). The present study was conducted to identify the signaling pathway responsible for the elevation of [ATP]c induced by sucralose. Previous studies have shown that sucralose elevates cyclic AMP (cAMP), activates phospholipase C (PLC) and stimulates Ca(2+) entry by a Na(+)-dependent mechanism in MIN6 cells. The addition of forskolin induced a marked elevation of cAMP, whereas it did not affect [ATP]c. Carbachol, an activator of PLC, did not increase [ATP]c. In addition, activation of protein kinase C by dioctanoylglycerol did not affect [ATP]c. In contrast, nifedipine, an inhibitor of the voltage-dependent Ca(2+) channel, significantly reduced [ATP]c response to sucralose. Removal of extracellular Na(+) nearly completely blocked sucralose-induced elevation of [ATP]c. Stimulation of Na(+) entry by adding a Na(+) ionophore monensin elevated [ATP]c. The monensin-induced elevation of [ATP]c was only partially inhibited by nifedipine and loading of BAPTA, both of which completely abolished elevation of [Ca(2+)]c. These results suggest that Na(+) entry is critical for the sucralose-induced elevation of [ATP]c. Both calcium-dependent and -independent mechanisms are involved in the action of sucralose.
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Affiliation(s)
- Longfei Li
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
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Hsiao YH, Hsu CH, Chen C. A High-Throughput Automated Microfluidic Platform for Calcium Imaging of Taste Sensing. Molecules 2016; 21:E896. [PMID: 27399663 PMCID: PMC6273845 DOI: 10.3390/molecules21070896] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 12/30/2022] Open
Abstract
The human enteroendocrine L cell line NCI-H716, expressing taste receptors and taste signaling elements, constitutes a unique model for the studies of cellular responses to glucose, appetite regulation, gastrointestinal motility, and insulin secretion. Targeting these gut taste receptors may provide novel treatments for diabetes and obesity. However, NCI-H716 cells are cultured in suspension and tend to form multicellular aggregates, preventing high-throughput calcium imaging due to interferences caused by laborious immobilization and stimulus delivery procedures. Here, we have developed an automated microfluidic platform that is capable of trapping more than 500 single cells into microwells with a loading efficiency of 77% within two minutes, delivering multiple chemical stimuli and performing calcium imaging with enhanced spatial and temporal resolutions when compared to bath perfusion systems. Results revealed the presence of heterogeneity in cellular responses to the type, concentration, and order of applied sweet and bitter stimuli. Sucralose and denatonium benzoate elicited robust increases in the intracellular Ca(2+) concentration. However, glucose evoked a rapid elevation of intracellular Ca(2+) followed by reduced responses to subsequent glucose stimulation. Using Gymnema sylvestre as a blocking agent for the sweet taste receptor confirmed that different taste receptors were utilized for sweet and bitter tastes. This automated microfluidic platform is cost-effective, easy to fabricate and operate, and may be generally applicable for high-throughput and high-content single-cell analysis and drug screening.
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Affiliation(s)
- Yi-Hsing Hsiao
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli 35053, Taiwan.
| | - Chia-Hsien Hsu
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli 35053, Taiwan.
| | - Chihchen Chen
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
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