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Langhans W, Watts AG, Spector AC. The elusive cephalic phase insulin response: triggers, mechanisms, and functions. Physiol Rev 2023; 103:1423-1485. [PMID: 36422994 PMCID: PMC9942918 DOI: 10.1152/physrev.00025.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/04/2022] [Accepted: 11/20/2022] [Indexed: 11/25/2022] Open
Abstract
The cephalic phase insulin response (CPIR) is classically defined as a head receptor-induced early release of insulin during eating that precedes a postabsorptive rise in blood glucose. Here we discuss, first, the various stimuli that elicit the CPIR and the sensory signaling pathways (sensory limb) involved; second, the efferent pathways that control the various endocrine events associated with eating (motor limb); and third, what is known about the central integrative processes linking the sensory and motor limbs. Fourth, in doing so, we identify open questions and problems with respect to the CPIR in general. Specifically, we consider test conditions that allow, or may not allow, the stimulus to reach the potentially relevant taste receptors and to trigger a CPIR. The possible significance of sweetness and palatability as crucial stimulus features and whether conditioning plays a role in the CPIR are also discussed. Moreover, we ponder the utility of the strict classical CPIR definition based on what is known about the effects of vagal motor neuron activation and thereby acetylcholine on the β-cells, together with the difficulties of the accurate assessment of insulin release. Finally, we weigh the evidence of the physiological and clinical relevance of the cephalic contribution to the release of insulin that occurs during and after a meal. These points are critical for the interpretation of the existing data, and they support a sharper focus on the role of head receptors in the overall insulin response to eating rather than relying solely on the classical CPIR definition.
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Affiliation(s)
- Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zürich, Schwerzenbach, Switzerland
| | - Alan G Watts
- Department of Biological Sciences, USC Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Alan C Spector
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida
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2
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Kobayashi K, Han L, Koyama T, Lu SN, Nishimura T. Sweet taste receptor subunit T1R3 regulates casein secretion and phosphorylation of STAT5 in mammary epithelial cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119448. [PMID: 36878266 DOI: 10.1016/j.bbamcr.2023.119448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/25/2023] [Accepted: 02/12/2023] [Indexed: 03/06/2023]
Abstract
During lactation, mammary epithelial cells (MECs) on the apical membrane are in contact with lactose in milk, while MECs on the basolateral membrane are in contact with glucose in blood. Both glucose and lactose are sweeteners that are sensed by a sweet taste receptor. Previously, we have shown that lactose exposure on the basolateral membrane, but not the apical membrane, inhibits casein production and phosphorylation of STAT5 in MECs. However, it remains unclear whether MECs have a sweet taste receptor. In this study, we confirmed that the sweet taste receptor subunit T1R3 existed in both the apical and basolateral membranes of MECs. Subsequently, we investigated the influence of apical and basolateral sucralose as a ligand for the sweet taste receptor using a cell culture model. In this model, upper and lower media were separated by the MEC layer with less-permeable tight junctions. The results showed in the absence of glucose, both apical and basolateral sucralose induced phosphorylation of STAT5, which is a positive transcriptional factor for milk production. In contrast, the T1R3 inhibitor basolateral lactisole reducing phosphorylated STAT5 and secreted caseins in the presence of glucose. Furthermore, exposure of the apical membrane to sucralose in the presence of glucose inhibited the phosphorylation of STAT5. Simultaneously, GLUT1 was partially translocated from the basolateral membrane to the cytoplasm in MECs. These results suggest that T1R3 functions as a sweet receptor and is closely involved in casein production in MECs.
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Affiliation(s)
- Ken Kobayashi
- Laboratory of Cell and Tissue Biology, Research Faculty of Agriculture, Hokkaido University, North 9, West 9, 060-8589 Sapporo, Japan.
| | - Liang Han
- Laboratory of Cell and Tissue Biology, Research Faculty of Agriculture, Hokkaido University, North 9, West 9, 060-8589 Sapporo, Japan
| | - Taku Koyama
- Laboratory of Cell and Tissue Biology, Research Faculty of Agriculture, Hokkaido University, North 9, West 9, 060-8589 Sapporo, Japan
| | - Shan-Ni Lu
- Laboratory of Cell and Tissue Biology, Research Faculty of Agriculture, Hokkaido University, North 9, West 9, 060-8589 Sapporo, Japan
| | - Takanori Nishimura
- Laboratory of Cell and Tissue Biology, Research Faculty of Agriculture, Hokkaido University, North 9, West 9, 060-8589 Sapporo, Japan
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3
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Baines DL, Vasiljevs S, Kalsi KK. Getting sweeter: new evidence for glucose transporters in specific cell types of the airway? Am J Physiol Cell Physiol 2023; 324:C153-C166. [PMID: 36409177 PMCID: PMC9829484 DOI: 10.1152/ajpcell.00140.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
New technologies such as single-cell RNA sequencing (scRNAseq) has enabled identification of the mRNA transcripts expressed by individual cells. This review provides insight from recent scRNAseq studies on the expression of glucose transporters in the epithelial cells of the airway epithelium from trachea to alveolus. The number of studies analyzed was limited, not all reported the full range of glucose transporters and there were differences between cells freshly isolated from the airways and those grown in vitro. Furthermore, glucose transporter mRNA transcripts were expressed at lower levels than other epithelial marker genes. Nevertheless, these studies highlighted that there were differences in cellular expression of glucose transporters. GLUT1 was the most abundant of the broadly expressed transporters that included GLUT8, 10, and 13. GLUT9 transcripts were more common in basal cells and GLUT12 in ionocytes/ciliated cells. In addition to alveolar cells, SGLT1 transcripts were present in secretory cells. GLUT3 mRNA transcripts were expressed in a cell cluster that expressed monocarboxylate (MCT2) transporters. Such distributions likely underlie cell-specific metabolic requirements to support proliferation, ion transport, mucous secretion, environment sensing, and airway glucose homeostasis. These studies have also highlighted the role of glucose transporters in the movement of dehydroascorbic acid/vitamin C/myoinositol/urate, which are factors important to the innate immune properties of the airways. Discrepancies remain between detection of mRNAs, protein, and function of glucose transporters in the lungs. However, collation of the data from further scRNAseq studies may provide a better consensus and understanding, supported by qPCR, immunohistochemistry, and functional experiments.
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Affiliation(s)
- Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, London, United Kingdom
| | - Stanislavs Vasiljevs
- Institute for Infection and Immunity, St George’s, University of London, London, United Kingdom
| | - Kameljit K. Kalsi
- Institute for Infection and Immunity, St George’s, University of London, London, United Kingdom
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4
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Veronese S, Merigo F, Sbarbati A. Did we forget the diffuse chemosensory system when studying COVID-19? Immunol Lett 2021; 231:26-27. [PMID: 33428993 PMCID: PMC7834028 DOI: 10.1016/j.imlet.2021.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 01/05/2021] [Indexed: 12/22/2022]
Affiliation(s)
- Sheila Veronese
- Department of Neuroscience, Biomedicine and Movement, University of Verona, 37134, Verona, Italy.
| | - Flavia Merigo
- Department of Neuroscience, Biomedicine and Movement, University of Verona, 37134, Verona, Italy
| | - Andrea Sbarbati
- Department of Neuroscience, Biomedicine and Movement, University of Verona, 37134, Verona, Italy
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5
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Ookoshi K, Yokoyama T, Saino T, Nakamuta N, Yamamoto Y. Morphological characterization of brush cells in the rat trachea. Tissue Cell 2020; 66:101399. [PMID: 32933721 DOI: 10.1016/j.tice.2020.101399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 10/24/2022]
Abstract
Brush cells have recently been classified as solitary chemosensory cells. However, tracheal brush cells have not been morphologically and immunohistochemically characterized yet. In the present study, the morphological and immunohistochemical characteristics of tracheal brush cells were analyzed using immunohistochemistry and scanning, and transmission electron microscopies. Brush cells in the tracheal epithelium were barrel-like or columnar in shape and were immunoreactive for villin. Scanning and transmission electron microscopies revealed densely arranged thick microvilli on the apical surface of tracheal brush cells and tubular membranous elements and/or vesicular formations in the supranuclear region. A morphometrical analysis of tracheal whole-mount preparations showed that the density of brush cells was greater in the cranial third and the mucosa on the annular ligament. Double immunofluorescence revealed that the morphology of villin-immunoreactive brush cells was distinct from other non-ciliated cells in the tracheal epithelium, i.e., MUC5AC-immunoreactive mucous cells, SNAP25-immunoreactive neuroendocrine cells, and GNAT3-immunoreactive solitary chemosensory cells. On the other hand, tracheal brush cells were immunoreactive for the marker proteins for intestinal brush cells, CK18, DCLK1, and Cox1; however, these antibodies also recognized cells other than brush cells. Furthermore, immunoreactivity for PKD2L1, a cation channel subunit, was detected in brush cells. The present results demonstrated that tracheal brush cells are independent cell types. These brush cells may be activated by acid and the secretion of prostaglandins. In conclusion, the present study revealed that tracheal brush cells are independent cell types based on the morphological and immunohistochemical characteristics.
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Affiliation(s)
- Kai Ookoshi
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Iwate 028-3694, Japan
| | - Tomoyuki Saino
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Iwate 028-3694, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan.
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Zappaterra M, Gioiosa S, Chillemi G, Zambonelli P, Davoli R. Muscle transcriptome analysis identifies genes involved in ciliogenesis and the molecular cascade associated with intramuscular fat content in Large White heavy pigs. PLoS One 2020; 15:e0233372. [PMID: 32428048 PMCID: PMC7237010 DOI: 10.1371/journal.pone.0233372] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023] Open
Abstract
Intramuscular fat content (IMF) is a complex trait influencing the technological and sensorial features of meat products and determining pork quality. Thus, we aimed at analyzing through RNA-sequencing the Semimembranosus muscle transcriptome of Italian Large White pigs to study the gene networks associated with IMF deposition. Two groups of samples were used; each one was composed of six unrelated pigs with extreme and divergent IMF content (0.67 ± 0.09% in low IMF vs. 6.81 ± 1.17% in high IMF groups) that were chosen from 950 purebred individuals. Paired-end RNA sequences were aligned to Sus scrofa genome assembly 11.1 and gene counts were analyzed using WGCNA and DeSeq2 packages in R environment. Interestingly, among the 58 differentially expressed genes (DEGs), several were related to primary cilia organelles (such as Lebercilin 5 gene), in addition to the genes involved in the regulation of cell differentiation, in the control of RNA-processing, and G-protein and ERK signaling pathways. Together with cilia-related genes, we also found in high IMF pigs an over-expression of the Fibroblast Growth Factor 2 (FGF2) gene, which in other animal species was found to be a regulator of ciliogenesis. Four WGCNA gene modules resulted significantly associated with IMF deposition: grey60 (P = 0.003), darkturquoise (P = 0.022), skyblue1 (P = 0.022), and lavenderblush3 (P = 0.030). The genes in the significant modules confirmed the results obtained for the DEGs, and the analysis with “cytoHubba” indicated genes controlling RNA splicing and cell differentiation as hub genes. Among the complex molecular processes affecting muscle fat depots, genes involved in primary cilia may have an important role, and the transcriptional reprogramming observed in high IMF pigs may be related to an FGF-related molecular cascade and to ciliogenesis, which in the literature have been associated with fibro-adipogenic precursor differentiation.
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Affiliation(s)
- Martina Zappaterra
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Science, University of Bologna, Bologna, Italy
| | - Silvia Gioiosa
- Super Computing Applications and Innovation Department (SCAI), CINECA, Rome, Italy
| | - Giovanni Chillemi
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), University of Tuscia, Viterbo, Italy
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), CNR, Bari, Italy
| | - Paolo Zambonelli
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Science, University of Bologna, Bologna, Italy
| | - Roberta Davoli
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Science, University of Bologna, Bologna, Italy
- Interdepartmental Centre of Agri-food Industrial Research (CIRI-AGRO), University of Bologna, Cesena, Italy
- * E-mail:
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7
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Brozzetti L, Sacchetto L, Cecchini MP, Avesani A, Perra D, Bongianni M, Portioli C, Scupoli M, Ghetti B, Monaco S, Buffelli M, Zanusso G. Neurodegeneration-Associated Proteins in Human Olfactory Neurons Collected by Nasal Brushing. Front Neurosci 2020; 14:145. [PMID: 32194369 PMCID: PMC7066258 DOI: 10.3389/fnins.2020.00145] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/05/2020] [Indexed: 12/12/2022] Open
Abstract
The olfactory neuroepithelium is located in the upper vault of the nasal cavity, lying on the olfactory cleft and projecting into the dorsal portion of the superior and middle turbinates beyond the mid-portion of the nasal septum. It is composed of a variety of cell types including olfactory sensory neurons, supporting glial-like cells, microvillar cells, and basal stem cells. The cells of the neuroepithelium are often intermingled with respiratory and metaplastic epithelial cells. Olfactory neurons undergo a constant self-renewal in the timespan of 2–3 months; they are directly exposed to the external environment, and thus they are vulnerable to physical and chemical injuries. The latter might induce metabolic perturbations and ultimately be the cause of cell death. However, the lifespan of olfactory neurons is biologically programmed, and for this reason, these cells have an accelerated metabolic cycle leading to an irreversible apoptosis. These characteristics make these cells suitable for research related to nerve cell degeneration and aging. Recent studies have shown that a non-invasive and painless olfactory brushing procedure allows an efficient sampling from the olfactory neuroepithelium. This approach allows to detect the pathologic prion protein in patients with sporadic Creutzfeldt–Jakob disease, using the real-time quaking-induced conversion assay. Investigating the expression of all the proteins associated to neurodegeneration in the cells of the olfactory mucosa is a novel approach toward understanding the pathogenesis of human neurodegenerative diseases. Our aim was to investigate the expression of α-synuclein, β-amyloid, tau, and TDP-43 in the olfactory neurons of normal subjects. We showed that these proteins that are involved in neurodegenerative diseases are expressed in olfactory neurons. These findings raise the question on whether a relationship exists between the mechanisms of protein aggregation that occur in the olfactory bulb during the early stage of the neurodegenerative process and the protein misfolding occurring in the olfactory neuroepithelium.
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Affiliation(s)
- Lorenzo Brozzetti
- Neuropathology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Luca Sacchetto
- Otolaryngology Section, Department of Surgery, Dentistry, Paediatrics and Gynaecology, University of Verona, Verona, Italy
| | - Maria Paola Cecchini
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Anna Avesani
- Physiology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Daniela Perra
- Neuropathology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Matilde Bongianni
- Neuropathology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Corinne Portioli
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Maria Scupoli
- Biology and Genetics Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Bernardino Ghetti
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Salvatore Monaco
- Neuropathology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Mario Buffelli
- Physiology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Gianluigi Zanusso
- Neuropathology Section, Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
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8
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Lasconi C, Pifferi S, Hernandez-Clavijo A, Merigo F, Cecchini MP, Gonzalez-Velandia KY, Agostinelli E, Sbarbati A, Menini A. Bitter tastants and artificial sweeteners activate a subset of epithelial cells in acute tissue slices of the rat trachea. Sci Rep 2019; 9:8834. [PMID: 31222082 PMCID: PMC6586933 DOI: 10.1038/s41598-019-45456-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 06/07/2019] [Indexed: 02/06/2023] Open
Abstract
Bitter and sweet receptors (T2Rs and T1Rs) are expressed in many extra-oral tissues including upper and lower airways. To investigate if bitter tastants and artificial sweeteners could activate physiological responses in tracheal epithelial cells we performed confocal Ca2+ imaging recordings on acute tracheal slices. We stimulated the cells with denatonium benzoate, a T2R agonist, and with the artificial sweeteners sucralose, saccharin and acesulfame-K. To test cell viability we measured responses to ATP. We found that 39% of the epithelial cells responding to ATP also responded to bitter stimulation with denatonium benzoate. Moreover, artificial sweeteners activated different percentages of the cells, ranging from 5% for sucralose to 26% for saccharin, and 27% for acesulfame-K. By using carbenoxolone, a gap junction blocker, we excluded that responses were mainly mediated by Ca2+ waves through cell-to-cell junctions. Pharmacological experiments showed that both denatonium and artificial sweeteners induced a PLC-mediated release of Ca2+ from internal stores. In addition, bitter tastants and artificial sweeteners activated a partially overlapping subpopulation of tracheal epithelial cells. Our results provide new evidence that a subset of ATP-responsive tracheal epithelial cells from rat are activated by both bitter tastants and artificial sweeteners.
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Affiliation(s)
- Chiara Lasconi
- Department of Neurosciences, Biomedicine and Movement Sciences, Anatomy and Histology Section, University of Verona, School of Medicine, Verona, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, International School for Advanced Studies, Trieste, Italy.
| | | | - Flavia Merigo
- Department of Neurosciences, Biomedicine and Movement Sciences, Anatomy and Histology Section, University of Verona, School of Medicine, Verona, Italy
| | - Maria Paola Cecchini
- Department of Neurosciences, Biomedicine and Movement Sciences, Anatomy and Histology Section, University of Verona, School of Medicine, Verona, Italy.
| | | | - Emilio Agostinelli
- Neurobiology Group, SISSA, International School for Advanced Studies, Trieste, Italy
| | - Andrea Sbarbati
- Department of Neurosciences, Biomedicine and Movement Sciences, Anatomy and Histology Section, University of Verona, School of Medicine, Verona, Italy
| | - Anna Menini
- Neurobiology Group, SISSA, International School for Advanced Studies, Trieste, Italy
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9
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Jiang J, Qi L, Wei Q, Shi F. Effects of daily exposure to saccharin sodium and rebaudioside A on the ovarian cycle and steroidogenesis in rats. Reprod Toxicol 2018; 76:35-45. [DOI: 10.1016/j.reprotox.2017.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/08/2017] [Accepted: 12/14/2017] [Indexed: 10/18/2022]
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10
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Molina SA, Moriarty HK, Infield DT, Imhoff BR, Vance RJ, Kim AH, Hansen JM, Hunt WR, Koval M, McCarty NA. Insulin signaling via the PI3-kinase/Akt pathway regulates airway glucose uptake and barrier function in a CFTR-dependent manner. Am J Physiol Lung Cell Mol Physiol 2017; 312:L688-L702. [PMID: 28213469 PMCID: PMC5451595 DOI: 10.1152/ajplung.00364.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 12/13/2022] Open
Abstract
Cystic fibrosis-related diabetes is the most common comorbidity associated with cystic fibrosis (CF) and correlates with increased rates of lung function decline. Because glucose is a nutrient present in the airways of patients with bacterial airway infections and because insulin controls glucose metabolism, the effect of insulin on CF airway epithelia was investigated to determine the role of insulin receptors and glucose transport in regulating glucose availability in the airway. The response to insulin by human airway epithelial cells was characterized by quantitative PCR, immunoblot, immunofluorescence, and glucose uptake assays. Phosphatidylinositol 3-kinase/protein kinase B (Akt) signaling and cystic fibrosis transmembrane conductance regulator (CFTR) activity were analyzed by pharmacological and immunoblot assays. We found that normal human primary airway epithelial cells expressed glucose transporter 4 and that application of insulin stimulated cytochalasin B-inhibitable glucose uptake, consistent with a requirement for glucose transporter translocation. Application of insulin to normal primary human airway epithelial cells promoted airway barrier function as demonstrated by increased transepithelial electrical resistance and decreased paracellular flux of small molecules. This provides the first demonstration that airway cells express insulin-regulated glucose transporters that act in concert with tight junctions to form an airway glucose barrier. However, insulin failed to increase glucose uptake or decrease paracellular flux of small molecules in human airway epithelia expressing F508del-CFTR. Insulin stimulation of Akt1 and Akt2 signaling in CF airway cells was diminished compared with that observed in airway cells expressing wild-type CFTR. These results indicate that the airway glucose barrier is regulated by insulin and is dysfunctional in CF.
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Affiliation(s)
- Samuel A Molina
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia;
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Hannah K Moriarty
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Daniel T Infield
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonology, Allergy & Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia; and
| | - Barry R Imhoff
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonology, Allergy & Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia; and
| | - Rachel J Vance
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Agnes H Kim
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Jason M Hansen
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
| | - William R Hunt
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Michael Koval
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia
| | - Nael A McCarty
- Emory+Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
- Division of Pulmonology, Allergy & Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia; and
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11
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Merigo F, Boschi F, Lasconi C, Benati D, Sbarbati A. Molecules implicated in glucose homeostasis are differentially expressed in the trachea of lean and obese Zucker rats. Eur J Histochem 2016; 60:2557. [PMID: 26972710 PMCID: PMC4800246 DOI: 10.4081/ejh.2016.2557] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 11/18/2015] [Accepted: 11/30/2015] [Indexed: 01/16/2023] Open
Abstract
Recent studies indicate that the processes mediated by the (T1R2/T1R3) glucose/sugar receptor of gustatory cells in the tongue, and hormones like leptin and ghrelin contribute to the regulation of glucose homeostasis. Altered plasma levels of leptin and ghrelin are associated with obesity both in humans and rodents. In the present study, we evaluated the ultrastructure of the mucosa, and the expression of molecules implicated in the regulation of glucose homeostasis (GLUT2, SGLT1, T1R3, ghrelin and its receptor) in the trachea of an animal model of obesity (Zucker rats). We found that the tracheal epithelium of obese animals was characterized by the presence of poorly differentiated cells. Ciliated and secretory cells were the cell lineages with greatest loss of differentiation. Severe epithelial alterations were associated with marked deposit of extracellular matrix in the lamina propria. The expression pattern of GLUT2 and SGLT1 glucose transporters was similar in the trachea of both the Zucker rat genotypes, whereas that of T1R3 was reduced in ciliated cells of obese rats. A different immunolocalization for ghrelin was also found in the trachea of obese rats. In conclusion, the tracheal morphological alterations in obese animals seem to compromise the expression of molecules involved in the homeostasis of glucose.
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12
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Sclafani A, Koepsell H, Ackroff K. SGLT1 sugar transporter/sensor is required for post-oral glucose appetition. Am J Physiol Regul Integr Comp Physiol 2016; 310:R631-9. [PMID: 26791832 DOI: 10.1152/ajpregu.00432.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 01/14/2016] [Indexed: 01/27/2023]
Abstract
Recent findings suggest that the intestinal sodium-glucose transporter 1 (SGLT1) glucose transporter and sensor mediates, in part, the appetite-stimulation actions of intragastric (IG) glucose and nonmetabolizable α-methyl-d-glucopyranoside (MDG) infusions in mice. Here, we investigated the role of SGLT1 in sugar conditioning using SGLT1 knockout (KO) and C57BL/6J wild-type (WT) mice. An initial experiment revealed that both KO and WT mice maintained on a very low-carbohydrate diet display normal preferences for saccharin, which was used in the flavored conditioned stimulus (CS) solutions. In experiment 2, mice were trained to drink one flavored solution (CS+) paired with an IG MDG infusion and a different flavored solution (CS-) paired with IG water infusion. In contrast to WT mice, KO mice decreased rather than increased the intake of the CS+ during training and failed to prefer the CS+ over the CS- in a choice test. In experiment 3, the KO mice also decreased their intake of a CS+ paired with IG glucose and avoided the CS+ in a choice test, unlike WT mice, which preferred the CS+ to CS-. In experiment 4, KO mice, like WT mice preferred a glucose + saccharin solution to a saccharin solution. These findings support the involvement of SGLT1 in post-oral glucose and MDG conditioning. The results also indicate that sugar malabsorption in KO mice has inhibitory effects on sugar intake but does not block their natural preference for sweet taste.
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Affiliation(s)
- Anthony Sclafani
- Department of Psychology, Brooklyn College, City University of New York, Brooklyn, New York; and Cognition, Brain, and Behavior Doctoral Subprogram, Graduate School, City University of New York, New York, New York; and
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Würzburg, Germany
| | - Karen Ackroff
- Department of Psychology, Brooklyn College, City University of New York, Brooklyn, New York; and Cognition, Brain, and Behavior Doctoral Subprogram, Graduate School, City University of New York, New York, New York; and
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Hao Y, Huang J, Gu Y, Liu C, Li H, Liu J, Ren J, Yang Z, Peng S, Wang W, Li R. Metallothionein deficiency aggravates depleted uranium-induced nephrotoxicity. Toxicol Appl Pharmacol 2015; 287:306-15. [DOI: 10.1016/j.taap.2015.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 04/29/2015] [Accepted: 06/27/2015] [Indexed: 02/07/2023]
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Abstract
The G-protein-coupled receptor molecules and downstream effectors that are used by taste buds to detect sweet, bitter, and savory tastes are also utilized by chemoresponsive cells of the airways to detect irritants. Here, we describe the different cell types in the airways that utilize taste-receptor signaling to trigger protective epithelial and neural responses to potentially dangerous toxins and bacterial infection.
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Affiliation(s)
- Marco Tizzano
- Department of Cell & Developmental Biology, Rocky Mountain Taste & Smell Center, University of Colorado School of Medicine, Aurora, Colorado, USA
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Simon BR, Learman BS, Parlee SD, Scheller EL, Mori H, Cawthorn WP, Ning X, Krishnan V, Ma YL, Tyrberg B, MacDougald OA. Sweet taste receptor deficient mice have decreased adiposity and increased bone mass. PLoS One 2014; 9:e86454. [PMID: 24466105 PMCID: PMC3899259 DOI: 10.1371/journal.pone.0086454] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/10/2013] [Indexed: 12/16/2022] Open
Abstract
Functional expression of sweet taste receptors (T1R2 and T1R3) has been reported in numerous metabolic tissues, including the gut, pancreas, and, more recently, in adipose tissue. It has been suggested that sweet taste receptors in these non-gustatory tissues may play a role in systemic energy balance and metabolism. Smaller adipose depots have been reported in T1R3 knockout mice on a high carbohydrate diet, and sweet taste receptors have been reported to regulate adipogenesis in vitro. To assess the potential contribution of sweet taste receptors to adipose tissue biology, we investigated the adipose tissue phenotypes of T1R2 and T1R3 knockout mice. Here we provide data to demonstrate that when fed an obesogenic diet, both T1R2 and T1R3 knockout mice have reduced adiposity and smaller adipocytes. Although a mild glucose intolerance was observed with T1R3 deficiency, other metabolic variables analyzed were similar between genotypes. In addition, food intake, respiratory quotient, oxygen consumption, and physical activity were unchanged in T1R2 knockout mice. Although T1R2 deficiency did not affect adipocyte number in peripheral adipose depots, the number of bone marrow adipocytes is significantly reduced in these knockout animals. Finally, we present data demonstrating that T1R2 and T1R3 knockout mice have increased cortical bone mass and trabecular remodeling. This report identifies novel functions for sweet taste receptors in the regulation of adipose and bone biology, and suggests that in these contexts, T1R2 and T1R3 are either dependent on each other for activity or have common independent effects in vivo.
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Affiliation(s)
- Becky R. Simon
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Brian S. Learman
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sebastian D. Parlee
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Erica L. Scheller
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Hiroyuki Mori
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - William P. Cawthorn
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Musculoskeletal Research, Lilly Research Laboratories, Indianapolis, Indiana, United States of America
| | - Xiaomin Ning
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Venkatesh Krishnan
- Musculoskeletal Research, Lilly Research Laboratories, Indianapolis, Indiana, United States of America
| | - Yanfei L. Ma
- Musculoskeletal Research, Lilly Research Laboratories, Indianapolis, Indiana, United States of America
| | - Björn Tyrberg
- Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, Maryland, United States of America
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida, United States of America
| | - Ormond A. MacDougald
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Saunders CJ, Reynolds SD, Finger TE. Chemosensory brush cells of the trachea. A stable population in a dynamic epithelium. Am J Respir Cell Mol Biol 2013; 49:190-6. [PMID: 23526223 DOI: 10.1165/rcmb.2012-0485oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Tracheal brush cells (BCs) are specialized epithelial chemosensors that use the canonical taste transduction cascade to detect irritants. To test whether BCs are replaced at the same rate as other cells in the surrounding epithelium of adult mice, we used 5-bromo-2'-deoxyuridine (BrdU) to label dividing cells. Although scattered BrdU-labeled epithelial cells are present 5-20 days after BrdU, no BCs are labeled. These data indicate that BCs comprise a relatively static population. To determine how BCs are generated during development, we injected 5-day-old mice with BrdU and found labeled BCs and non-BC epithelial cells 5 days after BrdU. During the next 60 days, the percentage of labeled BCs increased, whereas the percentage of other labeled cell types decreased. These data suggest that BCs are generated from non-BC progenitor cells during postnatal tracheal growth. To test whether the adult epithelium retains the capacity to generate BCs, tracheal epithelial cells were recovered from adult mice and grown in an air-liquid interface (ALI) culture. After transition to differentiation conditions, BCs are detected, and comprise 1% of the total cell population by Day 14. BrdU added to cultures before the differentiation of BCs was chased into BCs, indicating that the increase in BC density is attributable to the proliferation of a non-BC progenitor. We conclude that: (1) BCs are normally a static population in adult mice; (2) BC progenitors proliferate and differentiate during neonatal development; and (3) BCs can be regenerated from a proliferative population resident in adult epithelium.
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Affiliation(s)
- Cecil J Saunders
- Rocky Mountain Taste and Smell Center, Neuroscience Program, Department of Cellular and Developmental Biology, University of Colorado School of Medicine and Anschutz Medical Center, Aurora, CO 80045, USA.
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