Mathematical modeling of white adipocyte exocytosis predicts adiponectin secretion and quantifies the rates of vesicle exo- and endocytosis
Journal article, 2017

Adiponectin is a hormone secreted from white adipocytes and takes part in the regulation of several metabolic processes. Although the pathophysiological importance of adiponectin has been thoroughly investigated, the mechanisms controlling its release are only partly understood. We have recently shown that adiponectin is secreted via regulated exocytosis of adiponectin-containing vesicles, that adiponectin exocytosis is stimulated by cAMP-dependent mechanisms, and that Ca2+ and ATP augment the cAMP-triggered secretion. However, much remains to be discovered regarding the molecular and cellular regulation of adiponectin release. Here, we have used mathematical modeling to extract detailed information contained within our previously obtained high-resolution patch-clamp time-resolved capacitance recordings to produce the first model of adiponectin exocytosis/secretion that combines all mechanistic knowledge deduced from electrophysiological experimental series. This model demonstrates that our previous understanding of the role of intracellular ATP in the control of adiponectin exocytosis needs to be revised to include an additional ATP-dependent step. Validation of the model by introduction of data of secreted adiponectin yielded a very close resemblance between the simulations and experimental results. Moreover, we could show that Ca2+-dependent adiponectin endocytosis contributes to the measured capacitance signal, and we were able to predict the contribution of endocytosis to the measured exocytotic rate under different experimental conditions. In conclusion, using mathematical modeling of published and newly generated data, we have obtained estimates of adiponectin exo- and endocytosis rates, and we have predicted adiponectin secretion. We believe that our model should have multiple applications in the study of metabolic processes and hormonal control thereof.

exocytosis

electrophysiology

mathematical modeling

endocytosis

adiponectin

adipokine

adipocyte

Author

Cecilia Brännmark

Sahlgrenska Academy

William Lövfors

Sahlgrenska Academy

Linköping University

Ali M. Komai

Sahlgrenska Academy

Tom Axelsson

Linköping University

Mickaël F. El Hachmane

Sahlgrenska Academy

Musovic Saliha

Sahlgrenska Academy

Alexandra Paul

Chalmers, Biology and Biological Engineering, Chemical Biology

Elin Nyman

AstraZeneca AB

Charlotta S Olofsson

University of Gothenburg

Sahlgrenska Academy

Journal of Biological Chemistry

0021-9258 (ISSN) 1083-351X (eISSN)

Vol. 292 49 20032-20043

Subject Categories

Cell Biology

Cell and Molecular Biology

Physiology

Information Science

Mathematical Analysis

Areas of Advance

Life Science Engineering (2010-2018)

DOI

10.1074/jbc.M117.801225

More information

Latest update

3/23/2018