1
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Rafiei N, Moghadam MG, Au A, Regeenes R, Chidambaram S, Liang T, Wang Y, Yip CM, Gaisano H, Rocheleau JV. Design of a versatile microfluidic device for imaging precision-cut-tissue slices. Biofabrication 2022; 14. [PMID: 35793653 DOI: 10.1088/1758-5090/ac7eea] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 07/06/2022] [Indexed: 11/12/2022]
Abstract
Precision-cut-tissues (PCTs), which preserve many aspects of a tissue's microenvironment, are typically imaged using conventional sample dishes and chambers. These can require large amounts of reagent and, when used for flow-through experiments, the shear forces applied on the tissues are often ill-defined. Their physical design also makes it difficult to image large volumes and repetitively image smaller regions of interest in the living slice. We report here on the design of a versatile microfluidic device capable of holding mouse or human pancreas PCTs for 3D fluorescence imaging using confocal and selective plane illumination microscopy (SPIM). Our design positions PCTs within a 5 × 5 mm × 140µm deep chamber fitted with 150µm tall channels to facilitate media exchange. Shear stress in the device is localized to small regions on the surface of the tissue and can be easily controlled. This design allows for media exchange at flowrates ∼10-fold lower than those required for conventional chambers. Finally, this design allows for imaging the same immunofluorescently labeled PCT with high resolution on a confocal and with large field of view on a SPIM, without adversely affecting image quality.
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Affiliation(s)
- Nafiseh Rafiei
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada
| | - Mohammadamir G Moghadam
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada.,Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Aaron Au
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Romario Regeenes
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada.,Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | | | - Tao Liang
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Yufeng Wang
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada.,Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Christopher M Yip
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Herbert Gaisano
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada.,Department of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Jonathan V Rocheleau
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada.,Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Department of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
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2
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Fei K, Zhang J, Yuan J, Xiao P. Present Application and Perspectives of Organoid Imaging Technology. Bioengineering (Basel) 2022; 9:bioengineering9030121. [PMID: 35324810 PMCID: PMC8945799 DOI: 10.3390/bioengineering9030121] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/23/2022] [Accepted: 03/13/2022] [Indexed: 11/18/2022] Open
Abstract
An organoid is a miniaturized and simplified in vitro model with a similar structure and function to a real organ. In recent years, the use of organoids has increased explosively in the field of growth and development, disease simulation, drug screening, cell therapy, etc. In order to obtain necessary information, such as morphological structure, cell function and dynamic signals, it is necessary and important to directly monitor the culture process of organoids. Among different detection technologies, imaging technology is a simple and convenient choice and can realize direct observation and quantitative research. In this review, the principle, advantages and disadvantages of imaging technologies that have been applied in organoids research are introduced. We also offer an overview of prospective technologies for organoid imaging. This review aims to help biologists find appropriate imaging techniques for different areas of organoid research, and also contribute to the development of organoid imaging systems.
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3
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Lu Y, Zhang Q, Wang X, Zhou X, Zhu J. Effect of pH on volatile fatty acid production from anaerobic digestion of potato peel waste. BIORESOURCE TECHNOLOGY 2020; 316:123851. [PMID: 32738559 DOI: 10.1016/j.biortech.2020.123851] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 06/11/2023]
Abstract
In this study, potato peel waste was used as feedstock to produce volatile fatty acids (VFAs) by anaerobic digestion. The effects of different pH levels (pH 5.0, pH 7.0, pH 11.0, and uncontrolled pH) on VFA concentration and composition, intermediate products, and metabolic state were evaluated. The results showed that the highest total VFA production was achieved with pH 7.0 (41.9 g COD/L and 632.2 mg COD/g VSfed), followed by that with uncontrolled pH. Butyric acid was the dominant product under acidic pH, whereas acetic acid dominated under alkaline pH. The type of acidogenic fermentation at pH 7.0 was the mixed-acid type. The change in NADH level in the mixed-acid type of fermentation consisted of small fluctuations, enhancing the stability and efficiency of fermentation. The enzymatic activities of acetate kinase and butyrate kinase were slightly inhibited at pH 5.0 and 11.0, resulting in relatively low VFAs production.
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Affiliation(s)
- Yu Lu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, Shandong 255049, China
| | - Qi Zhang
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, Shandong 255049, China
| | - Xiangyou Wang
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, Shandong 255049, China
| | - Xiaonan Zhou
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, Shandong 255049, China
| | - Jiying Zhu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, Shandong 255049, China.
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4
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Neumann EK, Migas LG, Allen JL, Caprioli RM, Van de Plas R, Spraggins JM. Spatial Metabolomics of the Human Kidney using MALDI Trapped Ion Mobility Imaging Mass Spectrometry. Anal Chem 2020; 92:13084-13091. [PMID: 32668145 DOI: 10.1021/acs.analchem.0c02051] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Low molecular weight metabolites are essential for defining the molecular phenotypes of cells. However, spatial metabolomics tools often lack the sensitivity, specify, and spatial resolution to provide comprehensive descriptions of these species in tissue. MALDI imaging mass spectrometry (IMS) of low molecular weight ions is particularly challenging as MALDI matrix clusters are often nominally isobaric with multiple metabolite ions, requiring high resolving power instrumentation or derivatization to circumvent this issue. An alternative to this is to perform ion mobility separation before ion detection, enabling the visualization of metabolites without the interference of matrix ions. Additional difficulties surrounding low weight metabolite visualization include high resolution imaging, while maintaining sufficient ion numbers for broad and representative analysis of the tissue chemical complement. Here, we use MALDI timsTOF IMS to image low molecular weight metabolites at higher spatial resolution than most metabolite MALDI IMS experiments (20 μm) while maintaining broad coverage within the human kidney. We demonstrate that trapped ion mobility spectrometry (TIMS) can resolve matrix peaks from metabolite signal and separate both isobaric and isomeric metabolites with different distributions within the kidney. The added ion mobility data dimension dramatically increased the peak capacity for spatial metabolomics experiments. Through this improved sensitivity, we have found >40 low molecular weight metabolites in human kidney tissue, such as argininic acid, acetylcarnitine, and choline that localize to the cortex, medulla, and renal pelvis, respectively. Future work will involve further exploring metabolomic profiles of human kidneys as a function of age, sex, and race.
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Affiliation(s)
- Elizabeth K Neumann
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States.,Mass Spectrometry Research Center, Vanderbilt University, 465 21st Avenue S #9160, Nashville, Tennessee 37235, United States
| | - Lukasz G Migas
- Delft Center for Systems and Control, Delft University of Technology, Mekelweg 2, Building 34, 2628 CD Delft, The Netherlands
| | - Jamie L Allen
- Mass Spectrometry Research Center, Vanderbilt University, 465 21st Avenue S #9160, Nashville, Tennessee 37235, United States
| | - Richard M Caprioli
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States.,Mass Spectrometry Research Center, Vanderbilt University, 465 21st Avenue S #9160, Nashville, Tennessee 37235, United States.,Department of Pharmacology, Vanderbilt University, 2220 Pierce Avenue, Nashville, Tennessee 37232, United States.,Department of Medicine, Vanderbilt University, 465 21st Avenue S #9160, Nashville, Tennessee 37235, United States.,Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Station B 351822, Nashville, Tennessee 37235, United States
| | - Raf Van de Plas
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States.,Mass Spectrometry Research Center, Vanderbilt University, 465 21st Avenue S #9160, Nashville, Tennessee 37235, United States.,Delft Center for Systems and Control, Delft University of Technology, Mekelweg 2, Building 34, 2628 CD Delft, The Netherlands
| | - Jeffrey M Spraggins
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States.,Mass Spectrometry Research Center, Vanderbilt University, 465 21st Avenue S #9160, Nashville, Tennessee 37235, United States.,Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Station B 351822, Nashville, Tennessee 37235, United States
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5
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Bugarski M, Martins JR, Haenni D, Hall AM. Multiphoton imaging reveals axial differences in metabolic autofluorescence signals along the kidney proximal tubule. Am J Physiol Renal Physiol 2018; 315:F1613-F1625. [PMID: 30132348 DOI: 10.1152/ajprenal.00165.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Kidney proximal tubules (PTs) are densely packed with mitochondria, and defects in mitochondrial function are implicated in many kidney diseases. However, little is known about intrinsic mitochondrial function within PT cells. Here, using intravital multiphoton microscopy and live slices of mouse kidney cortex, we show that autofluorescence signals provide important functional readouts of redox state and substrate metabolism and that there are striking axial differences in signals along the PT. Mitochondrial NAD(P)H intensity was similar in both PT segment (S)1 and S2 and was sensitive to changes in respiratory chain (RC) redox state, whereas cytosolic NAD(P)H intensity was significantly higher in S2. Mitochondrial NAD(P)H increased in response to lactate and butyrate but decreased in response to glutamine and glutamate. Cytosolic NAD(P)H was sensitive to lactate and pyruvate and decreased dramatically in S2 in response to inhibition of glucose metabolism. Mitochondrial flavoprotein (FP) intensity was markedly higher in S2 than in S1 but was insensitive to changes in RC redox state. Mitochondrial FP signal increased in response to palmitate but decreased in response to glutamine and glutamate. Fluorescence lifetime decays were similar in both S1 and S2, suggesting that intensity differences are explained by differences in abundance of the same molecular species. Expression levels of known fluorescent mitochondrial FPs were higher in S2 than S1. In summary, substantial metabolic information can be obtained in kidney tissue using a label-free live imaging approach, and our findings suggest that metabolism is tailored to the specialized functions of S1 and S2 PT segments.
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Affiliation(s)
- Milica Bugarski
- Institute of Anatomy, University of Zurich , Zurich , Switzerland
| | | | - Dominik Haenni
- Institute of Anatomy, University of Zurich , Zurich , Switzerland.,Center for Microscopy and Image Analysis, University of Zurich , Zurich , Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich , Zurich , Switzerland.,Department of Nephrology, University Hospital Zurich , Zurich , Switzerland
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6
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Li G, Wu B, Ward MG, Chong ACN, Mukherjee S, Chen S, Hao M. Multifunctional in vivo imaging of pancreatic islets during diabetes development. J Cell Sci 2016; 129:2865-75. [PMID: 27270669 DOI: 10.1242/jcs.190843] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/27/2016] [Indexed: 01/13/2023] Open
Abstract
Pancreatic islet dysfunction leading to insufficient glucose-stimulated insulin secretion triggers the clinical onset of diabetes. How islet dysfunction develops is not well understood at the cellular level, partly owing to the lack of approaches to study single islets longitudinally in vivo Here, we present a noninvasive, high-resolution system to quantitatively image real-time glucose metabolism from single islets in vivo, currently not available with any other method. In addition, this multifunctional system simultaneously reports islet function, proliferation, vasculature and macrophage infiltration in vivo from the same set of images. Applying our method to a longitudinal high-fat diet study revealed changes in islet function as well as alternations in islet microenvironment. More importantly, this label-free system enabled us to image real-time glucose metabolism directly from single human islets in vivo for the first time, opening the door to noninvasive longitudinal in vivo studies of healthy and diabetic human islets.
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Affiliation(s)
- Ge Li
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Binlin Wu
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Meliza G Ward
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Angie C N Chong
- Department of Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Sushmita Mukherjee
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Shuibing Chen
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA Department of Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Mingming Hao
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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7
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Croce AC, Bottiroli G. Autofluorescence spectroscopy and imaging: a tool for biomedical research and diagnosis. Eur J Histochem 2014; 58:2461. [PMID: 25578980 PMCID: PMC4289852 DOI: 10.4081/ejh.2014.2461] [Citation(s) in RCA: 303] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/04/2014] [Indexed: 12/18/2022] Open
Abstract
Native fluorescence, or autofluorescence (AF), consists in the emission of light in the UV-visible, near-IR spectral range when biological substrates are excited with light at suitable wavelength. This is a well-known phenomenon, and the strict relationship of many endogenous fluorophores with morphofunctional properties of the living systems, influencing their AF emission features, offers an extremely powerful resource for directly monitoring the biological substrate condition. Starting from the last century, the technological progresses in microscopy and spectrofluorometry were convoying attention of the scientific community to this phenomenon. In the future, the interest in the autofluorescence will certainly continue. Current instrumentation and analytical procedures will likely be overcome by the unceasing progress in new devices for AF detection and data interpretation, while a progress is expected in the search and characterization of endogenous fluorophores and their roles as intrinsic biomarkers.
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Affiliation(s)
- A C Croce
- Institute of Molecular Genetics of the National Research Council, University of Pavia.
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8
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Differential stimulation of insulin secretion by GLP-1 and Kisspeptin-10. PLoS One 2014; 9:e113020. [PMID: 25401335 PMCID: PMC4234631 DOI: 10.1371/journal.pone.0113020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/20/2014] [Indexed: 12/19/2022] Open
Abstract
β-cells in the pancreatic islet respond to elevated plasma glucose by secreting insulin to maintain glucose homeostasis. In addition to glucose stimulation, insulin secretion is modulated by numerous G-protein coupled receptors (GPCRs). The GPCR ligands Kisspeptin-10 (KP) and glucagon-like peptide-1 (GLP-1) potentiate insulin secretion through Gq and Gs-coupled receptors, respectively. Despite many studies, the signaling mechanisms by which KP and GLP-1 potentiate insulin release are not thoroughly understood. We investigated the downstream signaling pathways of these ligands and their affects on cellular redox potential, intracellular calcium activity ([Ca2+]i), and insulin secretion from β-cells within intact murine islets. In contrast to previous studies performed on single β-cells, neither KP nor GLP-1 affect [Ca2+]i upon stimulation with glucose. KP significantly increases the cellular redox potential, while no effect is observed with GLP-1, suggesting that KP and GLP-1 potentiate insulin secretion through different mechanisms. Co-treatment with KP and the Gβγ-subunit inhibitor gallein inhibits insulin secretion similar to that observed with gallein alone, while co-treatment with gallein and GLP-1 does not differ from GLP-1 alone. In contrast, co-treatment with the Gβγ activator mSIRK and either KP or GLP-1 stimulates insulin release similar to mSIRK alone. Neither gallein nor mSIRK alter [Ca2+]i activity in the presence of KP or GLP-1. These data suggest that KP likely alters insulin secretion through a Gβγ-dependent process that stimulates glucose metabolism without altering Ca2+ activity, while GLP-1 does so, at least partly, through a Gα-dependent pathway that is independent of both metabolism and Ca2+.
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9
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Schwetz TA, Ustione A, Piston DW. Neuropeptide Y and somatostatin inhibit insulin secretion through different mechanisms. Am J Physiol Endocrinol Metab 2013; 304:E211-21. [PMID: 23211512 PMCID: PMC3543566 DOI: 10.1152/ajpendo.00374.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pancreatic β-cells regulate glucose homeostasis by secreting insulin in response to glucose elevation and G protein-coupled receptor (GPCR) activation. Neuropeptide Y (NPY) and somatostatin (SST) attenuate insulin secretion through G(i) activation of Y(1) and SSTR(1&5) receptors, respectively. The downstream pathways altered by NPY and SST are poorly understood. Thus, we investigated these underlying mechanisms. NPY and SST increase cellular redox potential, suggesting that their inhibitory effect may not be mediated through metabolic inhibition. NPY does not affect intracellular calcium ([Ca(2+)](i)) activity upon glucose stimulation, whereas SST alters this response. G(βγ)-subunit inhibition by gallein attenuates insulin secretion but does not alter metabolism or [Ca(2+)](i). mSIRK-induced G(βγ) activation does not modulate glucose metabolism but increases [Ca(2+)](i) activity and potentiates insulin release. Cotreatment with gallein and NPY or SST reduces insulin secretion to levels similar to that of gallein alone. mSIRK and NPY cotreatment potentiates insulin secretion similarly to mSIRK alone, whereas mSIRK and SST treatment decreases insulin release. The data support a model where SST attenuates secretion through G(βγ) inhibition of Ca(2+) activity, while NPY activates a Ca(2+)-independent pathway mediated by G(α). GPCR ligands signal through multiple pathways to inhibit insulin secretion, and determining these mechanisms could lead to novel diabetic therapies.
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Affiliation(s)
- Tara A Schwetz
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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10
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Hall AM, Rhodes GJ, Sandoval RM, Corridon PR, Molitoris BA. In vivo multiphoton imaging of mitochondrial structure and function during acute kidney injury. Kidney Int 2013; 83:72-83. [PMID: 22992467 PMCID: PMC4136483 DOI: 10.1038/ki.2012.328] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mitochondrial dysfunction has been implicated in the pathogenesis of acute kidney injury due to ischemia and toxic drugs. Methods for imaging mitochondrial function in cells using confocal microscopy are well established; more recently, it was shown that these techniques can be utilized in ex vivo kidney tissue using multiphoton microscopy. We extended this approach in vivo and found that kidney mitochondrial structure and function can be imaged in anesthetized rodents using multiphoton excitation of endogenous and exogenous fluorophores. Mitochondrial nicotinamide adenine dinucleotide increased markedly in rat kidneys in response to ischemia. Following intravenous injection, the mitochondrial membrane potential-dependent dye TMRM was taken up by proximal tubules; in response to ischemia, the membrane potential dissipated rapidly and mitochondria became shortened and fragmented in proximal tubules. In contrast, the mitochondrial membrane potential and structure were better maintained in distal tubules. Changes in mitochondrial structure, nicotinamide adenine dinucleotide, and membrane potential were found in the proximal, but not distal, tubules after gentamicin exposure. These changes were sporadic, highly variable among animals, and were preceded by changes in non-mitochondrial structures. Thus, real-time changes in mitochondrial structure and function can be imaged in rodent kidneys in vivo using multiphoton excitation of endogenous and exogenous fluorophores in response to ischemia-reperfusion injury or drug toxicity.
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MESH Headings
- Acute Kidney Injury/etiology
- Acute Kidney Injury/pathology
- Acute Kidney Injury/physiopathology
- Animals
- Gentamicins/adverse effects
- Glutathione/metabolism
- Ischemia/complications
- Kidney/blood supply
- Kidney Tubules, Distal/metabolism
- Kidney Tubules, Distal/pathology
- Kidney Tubules, Distal/physiopathology
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Kidney Tubules, Proximal/physiopathology
- Male
- Membrane Potential, Mitochondrial/physiology
- Mice
- Mice, Inbred C57BL
- Microscopy, Fluorescence, Multiphoton/methods
- Mitochondria/pathology
- Mitochondria/physiology
- NAD/metabolism
- Rats
- Rats, Sprague-Dawley
- Rats, Wistar
- Reactive Oxygen Species/metabolism
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Affiliation(s)
- Andrew M Hall
- University College London Centre for Nephrology, Royal Free Hospital, London, UK.
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11
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Lam AK, Silva PN, Altamentova SM, Rocheleau JV. Quantitative imaging of electron transfer flavoprotein autofluorescence reveals the dynamics of lipid partitioning in living pancreatic islets. Integr Biol (Camb) 2012; 4:838-46. [PMID: 22733276 DOI: 10.1039/c2ib20075a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Pancreatic islet β-cells metabolically sense nutrients to maintain blood glucose homeostasis through the regulated secretion of insulin. Long-term exposure to a mixed supply of excess glucose and fatty acids induces β-cell dysfunction and type II diabetes in a process termed glucolipotoxicity. Despite a number of documented mechanisms for glucolipotoxicity, the interplay between glucose and fatty acid oxidation in islets remains debated. Here, we develop confocal imaging of electron transfer flavoprotein (ETF) autofluorescence to reveal the dynamics of fatty acid oxidation in living pancreatic islets. This method further integrates microfluidic devices to hold the islets stationary in flow, and thus achieve ETF imaging in the β-cells with high spatial and temporal resolution. Our data first confirm that ETF autofluorescence reflects electron transport chain (ETC) activity downstream of Complex I, consistent with a response directly related to fatty acid metabolism. Together with two-photon imaging of NAD(P)H and confocal imaging of lipoamide dehydrogenase (LipDH) autofluorescence, we show that the ETC predominantly draws electrons from LipDH/NADH-dependent Complex I rather than from ETF/FADH(2)-dependent ETF:CoQ oxidoreductase (ETF-QO). Islets stimulated with palmitate also show increased ETF redox state that is dose-dependently diminished by glucose (>10 mM). Furthermore, stimulation with a glucose bolus causes a two-tier drop in the ETF redox state at ∼5 and ∼20 min, suggesting glucose metabolism immediately increases ETC activity and later decreases fatty acid oxidation. Our results demonstrate the utility of ETF imaging in characterizing fatty acid-induced redox responses with high subcellular and temporal resolution. Our results further demonstrate a dominant role of glucose metabolism over fatty acid oxidation in β-cells even when presented with a mixed nutrient condition associated with glucolipotoxicity.
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Affiliation(s)
- Alan K Lam
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON Canada
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12
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Hall AM, Crawford C, Unwin RJ, Duchen MR, Peppiatt-Wildman CM. Multiphoton imaging of the functioning kidney. J Am Soc Nephrol 2011; 22:1297-304. [PMID: 21719788 DOI: 10.1681/asn.2010101054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Translating discoveries made in isolated renal cells and tubules to the in vivo situation requires the assessment of cellular function in intact live organs. Multiphoton imaging is a form of fluorescence microscopy that is ideally suited to working with whole tissues and organs, but adequately loading cells with fluorescence dyes in vivo remains a challenge. We found that recirculation of fluorescence dyes in the rat isolated perfused kidney (IPK) resulted in levels of intracellular loading that would be difficult to achieve in vivo. This technique allowed the imaging of tubular cell structure and function with multiphoton microscopy in an intact, functioning organ. We used this approach to follow processes in real time, including (1) relative rates of reactive oxygen species (ROS) production in different tubule types, (2) filtration and tubular uptake of low-molecular-weight dextrans and proteins, and (3) the effects of ischemia-reperfusion injury on mitochondrial function and cell structure. This study demonstrates that multiphoton microscopy of the isolated perfused kidney is a powerful technique for detailed imaging of cell structure and function in an intact organ.
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Affiliation(s)
- Andrew M Hall
- University College London Centre for Nephrology, Royal Free Hospital, Rowland Hill Street, London NW3 2PF, United Kingdom.
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13
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Monitoring of Cellular Dynamics with Electrochemical Detection Techniques. MODERN ASPECTS OF ELECTROCHEMISTRY 2011. [DOI: 10.1007/978-1-4614-0347-0_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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14
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Sanchez WY, Prow TW, Sanchez WH, Grice JE, Roberts MS. Analysis of the metabolic deterioration of ex vivo skin from ischemic necrosis through the imaging of intracellular NAD(P)H by multiphoton tomography and fluorescence lifetime imaging microscopy. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:046008. [PMID: 20799810 DOI: 10.1117/1.3466580] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ex vivo human skin has been used extensively for cosmeceutical and drug delivery studies, transplantable skin allografts, or skin flaps. However, it has a half-life of a few days due to ischemic necrosis. Traditional methods of assessing viability can be time-consuming and provide limited metabolic information. Using multiphoton tomography and fluorescence lifetime imaging (MPT-FLIM) we assess ischemic necrosis of ex vivo skin by NAD(P)H autofluorescence intensity and fluorescence lifetime. Ex vivo skin is stored in the presence and absence of nutrient media (Dulbecco Modified Eagle Medium) at -20, 4, and 37 degrees C and room temperature over a 7-day time course to establish different rates of metabolic deterioration. At higher temperatures we observe a decrease in NAD(P)H autofluorescence, higher image noise, and a significant increase in the average fluorescence lifetime (tau(m)) from approximately 1000 to 2000 ps. Additionally, significant distortions in NAD(P)H fluorescence lifetime histograms correspond to the reduction in autofluorescence. Skin kept at 4 degrees C, with or without media, showed the least change. Our findings suggest that MPT-FLIM enables useful noninvasive optical biopsies to monitor the metabolic state and deterioration of human skin for research and clinical purposes.
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Affiliation(s)
- Washington Y Sanchez
- University of Queensland, Princess Alexandra Hospital, Therapeutics Research Centre, Brisbane, Queensland, Australia
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15
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Lack of glucose recycling between endoplasmic reticulum and cytoplasm underlies cellular dysfunction in glucose-6-phosphatase-beta-deficient neutrophils in a congenital neutropenia syndrome. Blood 2010; 116:2783-92. [PMID: 20498302 DOI: 10.1182/blood-2009-12-258491] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
G6PC3 deficiency, characterized by neutropenia and neutrophil dysfunction, is caused by deficiencies in the endoplasmic reticulum (ER) enzyme glucose-6-phosphatase-β (G6Pase-β or G6PC3) that converts glucose-6-phosphate (G6P) into glucose, the primary energy source of neutrophils. Enhanced neutrophil ER stress and apoptosis underlie neutropenia in G6PC3 deficiency, but the exact functional role of G6Pase-β in neutrophils remains unknown. We hypothesized that the ER recycles G6Pase-β-generated glucose to the cytoplasm, thus regulating the amount of available cytoplasmic glucose/G6P in neutrophils. Accordingly, a G6Pase-β deficiency would impair glycolysis and hexose monophosphate shunt activities leading to reductions in lactate production, adenosine-5'-triphosphate (ATP) production, and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. Using annexin V-depleted neutrophils, we show that glucose transporter-1 translocation is impaired in neutrophils from G6pc3(-/-) mice and G6PC3-deficient patients along with impaired glucose uptake in G6pc3(-/-) neutrophils. Moreover, levels of G6P, lactate, and ATP are markedly lower in murine and human G6PC3-deficient neutrophils, compared with their respective controls. In parallel, the expression of NADPH oxidase subunits and membrane translocation of p47(phox) are down-regulated in murine and human G6PC3-deficient neutrophils. The results establish that in nonapoptotic neutrophils, G6Pase-β is essential for normal energy homeostasis. A G6Pase-β deficiency prevents recycling of ER glucose to the cytoplasm, leading to neutrophil dysfunction.
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Pan L, Zhang X, Song K, Tang B, Cai W, Wu X, Rupp RA, Xu J. Real-time imaging of autofluorescence NAD(P)H in single human neutrophils. APPLIED OPTICS 2009; 48:1042-1046. [PMID: 23567562 DOI: 10.1364/ao.48.001042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Real-time detection of NAD(P)H is particularly important for understanding physiological activities of neutrophils. We scrutinize the performance of weak light detection systems with electron multiplying CCDs (EMCCDs) with regard to the feasibility of valid investigations by autofluorescence NAD(P)H in single human neutrophils. The low-noise amplification facility of EMCCDs is indeed just adequate to permit detection at an irradiation level where neither quenching nor phototoxic effects occur. For demonstration, a neutrophil respiratory burst was triggered and observed in real time. Our low-intensity detection system fulfills all requirements for real-time investigations at high spatiotemporal resolution in the field of neutrophil physiology and pathology.
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Affiliation(s)
- Leiting Pan
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, Institute of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China
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Rocheleau JV, Piston DW. Chapter 4 Combining Microfluidics and Quantitative Fluorescence Microscopy to Examine Pancreatic Islet Molecular Physiology. Methods Cell Biol 2008; 89:71-92. [DOI: 10.1016/s0091-679x(08)00604-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Corriden R, Insel PA, Junger WG. A novel method using fluorescence microscopy for real-time assessment of ATP release from individual cells. Am J Physiol Cell Physiol 2007; 293:C1420-5. [PMID: 17699635 DOI: 10.1152/ajpcell.00271.2007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many cell types release ATP in response to mechanical or biochemical stimulation. The mechanisms responsible for this release, however, are not well understood and may differ among different cell types. In addition, there are numerous difficulties associated with studying the dynamics of ATP release immediately outside the cell membrane. Here, we report a new method that allows the visualization and quantification of ATP release by fluorescence microscopy. Our method utilizes a two-enzyme system that generates NADPH when ATP is present. NADPH is a fluorescent molecule that can be visualized by fluorescence microscopy using an excitation wavelength of 340 nm and an emission wavelength of 450 nm. The method is capable of detecting ATP concentrations <1 microM and has a dynamic range of up to 100 microM. Using this method, we visualized and quantified ATP release from human polymorphonuclear leukocytes and Jurkat T cells. We show that upon cell stimulation, the concentrations of ATP can reach levels of up to 80 microM immediately outside of the cell membrane. This new method should prove useful for the study of the mechanisms of release and functional role of ATP in various cell systems, including individual cells.
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Affiliation(s)
- Ross Corriden
- Department of Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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Kable EPW, Kiemer AK. Non-invasive live-cell measurement of changes in macrophage NAD(P)H by two-photon microscopy. Immunol Lett 2005; 96:33-8. [PMID: 15585305 DOI: 10.1016/j.imlet.2003.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 12/19/2003] [Accepted: 12/22/2003] [Indexed: 11/19/2022]
Abstract
Two-photon microscopy allows determination of UV-excitable fluorophores using long-wavelength light. We aimed to determine NAD(P)H autofluorescence as a measure for macrophage NADPH-oxidase activation. RAW264.7 macrophages were grown on glass coverslips and kept in HBSS for microscopic investigation. Cells were excited with 710 nm light and NAD(P)H autofluorescence was detected. Glucose as well as NaCN evoked an increase of NAD(P)H autofluorescence. Activators of NADPH oxidase lead to significantly decreased NAD(P)H autofluorescence. Therefore, this work shows the suitability of two-photon microscopy as a non-invasive method determining changes in phagocyte NAD(P)H upon activation.
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Affiliation(s)
- Eleanor P W Kable
- Electron Microscope Unit, Australian Key Centre for Microscopy & Microanalysis, Madsen Building FO9, University of Sydney, NSW 2006, Sydney, Australia
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Abstract
Since the earliest examination of cellular structures, biologists have been fascinated by observing cells using light microscopy. The advent of fluorescent labeling technologies plus the plethora of sophisticated light microscope techniques now available make studying dynamic processes in living cells almost commonplace. For anyone new to this area, however, it can be daunting to decide which techniques or equipment to try. Here, we aim to give a brief overview of the main approaches to live cell imaging, with some mention of their pros and cons.
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Affiliation(s)
- David J Stephens
- Department of Biochemistry, University of Bristol, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
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Evans ND, Gnudi L, Rolinski OJ, Birch DJS, Pickup JC. Non-invasive glucose monitoring by NAD(P)H autofluorescence spectroscopy in fibroblasts and adipocytes: a model for skin glucose sensing. Diabetes Technol Ther 2003; 5:807-16. [PMID: 14633346 DOI: 10.1089/152091503322527012] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aim of this study was to develop an in vitro cell-culture model of skin-component cells to test the hypothesis that glucose can be monitored non-invasively by measuring NAD(P)H-related fluorescence changes in tissues. 3T3-L1 fibroblasts and adipocytes were grown in culture, and the response to added glucose was assessed by changes in steady-state autofluorescence at 400-500 nm [excitation at 340 nm, an index of NAD(P)H]. We also studied glucose-related fluorescence changes in cells stained with the mitochondrial marker, rhodamine-123. Fibroblasts and adipocytes showed glucose-dependent increases in autofluorescence with both short- and long-term exposure. Spectral properties indicated that the fluorescence was due to NAD(P)H production. With 5-h exposure to glucose, the maximal response was at 10-15 mmol/L glucose. Cells stained with the fluorescent mitochondrial marker, rhodamine-123, showed an immediate and marked decrease in fluorescence when exposed to glucose. We conclude that glucose can be sensed non-invasively by cellular fluorescence changes in fibroblasts and adipocytes. This is a model for the further exploration of fluorescence-based non-invasive metabolic monitoring in human diabetes.
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Affiliation(s)
- Nicholas D Evans
- Metabolic Unit, Guy's, King's and St Thomas's School of Medicine, Guy's Hospital, London, United Kingdom
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Rocheleau JV, Head WS, Nicholson WE, Powers AC, Piston DW. Pancreatic islet beta-cells transiently metabolize pyruvate. J Biol Chem 2002; 277:30914-20. [PMID: 12070148 DOI: 10.1074/jbc.m202314200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pancreatic beta-cell metabolism was followed during glucose and pyruvate stimulation of pancreatic islets using quantitative two-photon NAD(P)H imaging. The observed redox changes, spatially separated between the cytoplasm and mitochondria, were compared with whole islet insulin secretion. As expected, both NAD(P)H and insulin secretion showed sustained increases in response to glucose stimulation. In contrast, pyruvate caused a much lower NAD(P)H response and did not generate insulin secretion. Low pyruvate concentrations decreased cytoplasmic NAD(P)H without affecting mitochondrial NAD(P)H, whereas higher concentrations increased cytoplasmic and mitochondrial levels. However, the pyruvate-stimulated mitochondrial increase was transient and equilibrated to near-base-line levels. Inhibitors of the mitochondrial pyruvate-transporter and malate-aspartate shuttle were utilized to resolve the glucose- and pyruvate-stimulated NAD(P)H response mechanisms. These data showed that glucose-stimulated mitochondrial NAD(P)H and insulin secretion are independent of pyruvate transport but dependent on NAD(P)H shuttling. In contrast, the pyruvate-stimulated cytoplasmic NAD(P)H response was enhanced by both inhibitors. Surprisingly the malate-aspartate shuttle inhibitor enabled pyruvate-stimulated insulin secretion. These data support a model in which glycolysis plays a dominant role in glucose-stimulated insulin secretion. Based on these data, we propose a mechanism for glucose-stimulated insulin secretion that includes allosteric inhibition of tricarboxylic acid cycle enzymes and pH dependence of mitochondrial pyruvate transport.
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Affiliation(s)
- Jonathan V Rocheleau
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232-0615, USA
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Birch DJ. Multiphoton excited fluorescence spectroscopy of biomolecular systems. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2001; 57:2313-2336. [PMID: 11603846 DOI: 10.1016/s1386-1425(01)00487-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recent work on the emerging application of multiphoton excitation to fluorescence studies of biomolecular dynamics and structure is reviewed. The fundamental principles and experimental techniques of multiphoton excitation are outlined, fluorescence lifetimes, anisotropy and spectra in membranes, proteins, hydrocarbons, skin, tissue and metabolites are featured, and future opportunities are highlighted.
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Affiliation(s)
- D J Birch
- Department of Physics and Applied Physics, Strathclyde University, Glasgow, Scotland, UK.
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Zhang C, Li Y, Ma H, Li S, Xue S, Chen D. Simultaneous multi-parameter observation of Harringtonine-treating HL-60 cells with both two-photon and confocal laser scanning microscopy. ACTA ACUST UNITED AC 2001; 44:383-91. [DOI: 10.1007/bf02879605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2000] [Indexed: 11/30/2022]
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Perriott LM, Kono T, Whitesell RR, Knobel SM, Piston DW, Granner DK, Powers AC, May JM. Glucose uptake and metabolism by cultured human skeletal muscle cells: rate-limiting steps. Am J Physiol Endocrinol Metab 2001; 281:E72-80. [PMID: 11404224 DOI: 10.1152/ajpendo.2001.281.1.e72] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To use primary cultures of human skeletal muscle cells to establish defects in glucose metabolism that underlie clinical insulin resistance, it is necessary to define the rate-determining steps in glucose metabolism and to improve the insulin response attained in previous studies. We modified experimental conditions to achieve an insulin effect on 3-O-methylglucose transport that was more than twofold over basal. Glucose phosphorylation by hexokinase limits glucose metabolism in these cells, because the apparent Michaelis-Menten constant of coupled glucose transport and phosphorylation is intermediate between that of transport and that of the hexokinase and because rates of 2-deoxyglucose uptake and phosphorylation are less than those of glucose. The latter reflects a preference of hexokinase for glucose over 2-deoxyglucose. Cellular NAD(P)H autofluorescence, measured using two-photon excitation microscopy, is both sensitive to insulin and indicative of additional distal control steps in glucose metabolism. Whereas the predominant effect of insulin in human skeletal muscle cells is to enhance glucose transport, phosphorylation, and steps beyond, it also determines the overall rate of glucose metabolism.
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Affiliation(s)
- L M Perriott
- Department of Veterans Affairs Medical Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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