scholarly journals A systems biology analysis of adrenergically stimulated adiponectin exocytosis in white adipocytes

2020 ◽  
Author(s):  
William Lövfors ◽  
Christian Simonsson ◽  
Ali M. Komai ◽  
Elin Nyman ◽  
Charlotta S. Olofsson ◽  
...  
Keyword(s):  
Systems Biology ◽  
Patch Clamp ◽  
Metabolic Diseases ◽  
Single Cells ◽  
Validation Data ◽  
Cl 316,243 ◽  
White Adipocytes ◽  
One Step ◽  
Intracellular Mediators ◽  
External Stimuli

ABSTRACTCirculating levels of the adipocyte hormone adiponectin are typically reduced in obesity and this deficiency has been linked to metabolic diseases. It is thus important to understand the mechanisms controlling adiponectin exocytosis. This understanding is hindered by the high complexity of the data and the underlying signaling network. To handle this complexity, we here analyze the data using systems biology mathematical modelling. Previously, we have developed a mathematical model for how different intracellular concentrations of Ca2+, cAMP and ATP affect adiponectin exocytosis (measured as increase in membrane capacitance). However, recent work has shown that adiponectin exocytosis is physiologically triggered via signaling pathways involving adrenergic β3 receptors (β3ARs). Therefore, we have herein developed a more comprehensive model that also includes adiponectin exocytosis stimulated by extracellularly applied epinephrine or the β3AR agonist CL 316,243. Our model can explain all previous patch-clamp data, as well as new data consisting of a combination of the intracellular mediators and extracellular adrenergic stimuli. Without changing the parameters, the model can accurately predict independent validation data with other combinations of patch-clamp pipette solutions and external stimuli. Finally, we use the model to perform new in silico experiments examining situations where corresponding wet lab experiments are difficult to perform. By this approach, we simulated adiponectin exocytosis in single cells, in response to the reduction of β3ARs that is observed in adipocytes from animals with obesity-induced diabetes. Our work brings us one step closer to understanding the intricate regulation of adiponectin exocytosis.

Systems Biology in Single Cells

2016 ◽  
pp. 31-53
Author(s):  
Macdara Glynn ◽  
Damien King ◽  
Jens Ducrée
Keyword(s):  
Systems Biology ◽  
Single Cells

Patch-Clamp Recording and RT-PCR on Single Cells

2003 ◽  
pp. 193-232 ◽  
Author(s):  
Bertrand Lambolez ◽  
Etienne Audinat ◽  
Pascal Bochet ◽  
Jean Rossier
Keyword(s):  
Patch Clamp ◽  
Single Cells ◽  
Rt Pcr ◽  
Patch Clamp Recording

scholarly journals Scd1 controls de novo beige fat biogenesis through succinate-dependent regulation of mitochondrial complex II

2020 ◽  
Vol 117 (5) ◽  
pp. 2462-2472 ◽  
Author(s):  
Keli Liu ◽  
Liangyu Lin ◽  
Qing Li ◽  
Yueqing Xue ◽  
Fanjun Zheng ◽  
...  
Keyword(s):  
Cell Fate ◽  
Metabolic Diseases ◽  
De Novo ◽  
Great Promise ◽  
Mitochondrial Complex ◽  
Differentiation Potential ◽  
Complex Ii ◽  
White Adipocytes ◽  
Beige Adipocytes ◽  
Adipocyte Progenitors

Preadipocytes can give rise to either white adipocytes or beige adipocytes. Owing to their distinct abilities in nutrient storage and energy expenditure, strategies that specifically promote “beiging” of adipocytes hold great promise for counterbalancing obesity and metabolic diseases. Yet, factors dictating the differentiation fate of adipocyte progenitors remain to be elucidated. We found that stearoyl-coenzyme A desaturase 1 (Scd1)-deficient mice, which resist metabolic stress, possess augmentation in beige adipocytes under basal conditions. Deletion of Scd1 in mature adipocytes expressing Fabp4 or Ucp1 did not affect thermogenesis in mice. Rather, Scd1 deficiency shifted the differentiation fate of preadipocytes from white adipogenesis to beige adipogenesis. Such effects are dependent on succinate accumulation in adipocyte progenitors, which fuels mitochondrial complex II activity. Suppression of mitochondrial complex II by Atpenin A5 or oxaloacetic acid reverted the differentiation potential of Scd1-deficient preadipocytes to white adipocytes. Furthermore, supplementation of succinate was found to increase beige adipocyte differentiation both in vitro and in vivo. Our data reveal an unappreciated role of Scd1 in determining the cell fate of adipocyte progenitors through succinate-dependent regulation of mitochondrial complex II.

Impedance spectra of patch clamp scenarios for single cells immobilized on a lab-on-a-chip

2013 ◽  
Vol 17 (2) ◽  
pp. 263-274 ◽  
Author(s):  
M. Alberti ◽  
D. Snakenborg ◽  
J. M. Lopacinska ◽  
M. Dufva ◽  
J. P. Kutter
Keyword(s):  
Patch Clamp ◽  
Single Cells ◽  
Lab On A Chip ◽  
Impedance Spectra

scholarly journals Symposium on single cell analysis and genomic approaches, Experimental Biology 2017 Chicago, Illinois, April 23, 2017

2017 ◽  
Vol 49 (9) ◽  
pp. 491-495
Author(s):  
Hilary A. Coller
Keyword(s):  
Single Cell ◽  
Single Cell Analysis ◽  
Single Cells ◽  
Experimental Biology ◽  
Intratumor Heterogeneity ◽  
Cell Analysis ◽  
Single Cell Genomics ◽  
Critical Issues ◽  
Cell To Cell Variability ◽  
External Stimuli

Emerging technologies for the analysis of genome-wide information in single cells have the potential to transform many fields of biology, including our understanding of cell states, the response of cells to external stimuli, mosaicism, and intratumor heterogeneity. At Experimental Biology 2017 in Chicago, Physiological Genomics hosted a symposium in which five leaders in the field of single cell genomics presented their recent research. The speakers discussed emerging methodologies in single cell analysis and critical issues for the analysis of single cell data. Also discussed were applications of single cell genomics to understanding the different types of cells within an organism or tissue and the basis for cell-to-cell variability in response to stimuli.

scholarly journals Phospholipase C inhibitor, U73122, releases intracellular Ca2+, potentiates Ins(1,4,5)P3-mediated Ca2+ release and directly activates ion channels in mouse pancreatic acinar cells

1997 ◽  
Vol 324 (2) ◽  
pp. 645-651 ◽  
Author(s):  
Hideo MOGAMI ◽  
LLOYD MILLS Chris ◽  
David V. GALLACHER
Keyword(s):  
Ion Channels ◽  
Patch Clamp ◽  
Phospholipase C ◽  
Single Cells ◽  
Specific Inhibitor ◽  
Acinar Cells ◽  
Cellular Systems ◽  
Pancreatic Acinar Cells ◽  
Intact Cells ◽  
Permeabilized Cells

It is recognized in many cellular systems that the receptor/G-protein activation of phospholipase C and Ins(1,4,5)P3 production is the transduction pathway regulating the release of Ca2+ from internal stores. Ca2+ signals can now be monitored at the level of single cells but the biochemical detection of Ins(1,4,5)P3 cannot match this resolution. It is often difficult or impossible to directly attribute responses evoked in single cells by putative phospholipase C-coupled agonists to changes in Ins(1,4,5)P3 levels. U73122 is an aminosteroid that is reported to act as a specific inhibitor of phospholipase C and it has become an important tool in establishing the link between phospholipase C activation and cellular Ca2+ signalling. In the present study we use both patch-clamp electrophysiology and the imaging of fluorescent Ca2+ indicators to investigate the effect of U73122 in mouse pancreatic acinar cells. The study reveals that U73122 has effects other than the inhibition of phospholipase C. U73122 can directly activate ion channels. It can itself promote the release of Ca2+ from intracellular stores in permeabilized cells and in intact cells it triggers a release of Ca2+ that is initiated specifically at the secretory pole of these morphologically and functionally polarized cells. We also present evidence that U73122 can potentiate the response to Ins(1,4,5)P3; this is seen both in permeabilized cells and in patch-clamp protocols in which cells are internally dialysed with submaximal concentrations of Ins(1,4,5)P3. The effects of U73122 are therefore multiple and not specific for the inhibition of phospholipase C. Importantly, all the effects described influence Ca2+ signalling yet in many experimental protocols some of these effects can go unnoticed and might in error be attributed simply to the inhibition of Ins(1,4,5)P3 production.

scholarly journals Novel insights into adipose tissue heterogeneity

2021 ◽  
Author(s):  
Tongtong Wang ◽  
Anand Kumar Sharma ◽  
Christian Wolfrum
Keyword(s):  
Adipose Tissue ◽  
Metabolic Diseases ◽  
Current Knowledge ◽  
Single Cells ◽  
Stromal Vascular Fraction ◽  
Current Data ◽  
Tissue Cell ◽  
Numerical Representation ◽  
Cell Composition ◽  
Adipose Tissue Cell

AbstractWhen normalized to volume, adipose tissue is comprised mainly of large lipid metabolizing and storing cells called adipocytes. Strikingly, the numerical representation of non-adipocytes, composed of a wide variety of cell types found in the so-called stromal vascular fraction (SVF), outnumber adipocytes by far. Besides its function in energy storage, adipose tissue has emerged as a versatile organ that regulates systemic metabolism and has therefore constituted an attractive target for the treatment of metabolic diseases. Recent high-resolution single cells/nucleus RNA seq data exemplify an intriguingly profound diversity of both adipocytes and SVF cells in all adipose depots, and the current data, while limited, demonstrate the significance of the intra-tissue cell composition in shaping the overall functionality of this tissue. Due to the complexity of adipose tissue, our understanding of the biological relevance of this heterogeneity and plasticity is fractional. Therefore, establishing atlases of adipose tissue cell heterogeneity is the first step towards generating an understanding of these functionalities. In this review, we will describe the current knowledge on adipose tissue cell composition and the heterogeneity of single-cell RNA sequencing, including the technical limitations.

scholarly journals Imaging action potential in single mammalian neurons by tracking the accompanying sub-nanometer mechanical motion

2017 ◽  
Author(s):  
Yunze Yang ◽  
Xian-Wei Liu ◽  
Hui Yu ◽  
Yan Guan ◽  
Shaopeng Wang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Patch Clamp ◽  
Action Potential ◽  
Fluorescence Detection ◽  
Action Potentials ◽  
Single Cells ◽  
Detection Methods ◽  
Imaging Method ◽  
Label Free ◽  
Mechanical Motion

AbstractAction potentials in neurons have been studied traditionally by the patch clamp and more recently by the fluorescence detection methods. Here we describe a label-free optical imaging method that can measure mechanical motion in single cells with sub-nanometer detection limit and sub-millisecond temporal resolution. Using the method, we have observed sub-nanometer mechanical motion accompanying the action potential in single mammalian neurons. The shape and width of the transient displacement are similar to those of the electrically recorded action potential, but the amplitude varies from neuron to neuron, and from one region of a neuron to another, ranging from 0.2 - 0.4 nm. The work indicates that action potentials may be studied non-invasively in single mammalian neurons by label-free imaging of the accompanying subnanometer mechanical motion.

scholarly journals Histone modification dynamics as revealed by a multicolor immunofluorescence-based single-cell analysis

2020 ◽  
Author(s):  
Yoko Hayashi-Takanaka ◽  
Yuto Kina ◽  
Fumiaki Nakamura ◽  
Leontine E. Becking ◽  
Yoichi Nakao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Histone Modifications ◽  
Histone Deacetylases ◽  
Single Cell Analysis ◽  
Marine Organism ◽  
Single Cells ◽  
Cell Types ◽  
Transient Overexpression ◽  
Overexpression System ◽  
External Stimuli

AbstractPost-translational modifications on histones can be stable epigenetic marks and transient signals that can occur in response to internal and external stimuli. Levels of histone modifications fluctuate during the cell cycle and vary among different cell types. Here we describe a simple system to monitor the levels of multiple histone modifications in single cells by multicolor immunofluorescence using directly labeled modification-specific antibodies. We first analyzed histone H3 and H4 modifications during the cell cycle. Levels of active marks, such as acetylation and H3K4 methylation, were increased during the S phase, in association with chromatin duplication. By contrast, levels of some repressive modifications gradually increased during the G2 and the next G1 phases. We applied this method to validate the target modifications of various histone demethylases in cells using a transient overexpression system. We also screened chemical compounds in marine organism extracts that affect histone modifications and identified psammaplin A, which was previously reported to inhibit histone deacetylases. Thus, the method presented here is a powerful and convenient tool for analyzing the changes in histone modifications.

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