Shape and Volume of Living Aldosterone-Sensitive Cells Imaged with the Atomic Force Microscope

Schneider, Stefan W.; Matzke, R.; Radmacher, Manfred; Oberleithner, Hans

doi:10.1385/1-59259-647-9:255

Cited by 22 publications

(36 citation statements)

References 36 publications

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“…Strain is the ratio of the change in length to initial length. Typical parameters for unfixed cells are in the range of 1 to 10 kPa and up to 100 kPa for fixed ones (for example, [65,128,138]). As a comparison, the Young's modulus for rubber is about 2 MPa and for glass about 1 GPa [138].…”

Section: Force Mappingmentioning

confidence: 99%

“…The contact point is usually hard to determine in soft samples, as the force plot becomes shallower with decreasing Young's moduli [44,122,138]. Furthermore, common AFM tips have a conical or pyramidal geometry.…”

Section: Force Mappingmentioning

confidence: 99%

“…The contact area increases accordingly with the indentation depth. These problems have been solved by the application of theoretical models, which meet the practical requirements of AFM force mapping [33,122,138,149]. In short, Hertz [63] found in 1882 an analytical solution that describes the elastic deformation of two spheres touching under load.…”

Section: Force Mappingmentioning

confidence: 99%

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Probing cellular microenvironments and tissue remodeling by atomic force microscopy

Ludwig

Kirmse

Poole

et al. 2007

Pflugers Arch - Eur J Physiol

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The function of cells is strongly determined by the properties of their extracellular microenvironment. Biophysical parameters like environmental stiffness and fiber orientation in the surrounding matrix are important determinants of cell adhesion and migration. Processes like tissue maintenance, wound repair, cancer cell invasion, and morphogenesis depend critically on the ability of cells to actively sense and remodel their surroundings. Pericellular proteolytic activity and adaptation of migration tactics to the environment are strategies to achieve this aim. Little is known about the distinct regulatory mechanisms that are involved in these processes. The system's critical biophysical and biochemical determinants are well accessible by atomic force microscopy (AFM), a unique tool for functional, nanoscale probing and morphometric, highresolution imaging of processes in live cells. This review highlights common principles of tissue remodeling and focuses on application examples of different AFM techniques, for example elasticity mapping, the combination of AFM and fluorescence microscopy, the morphometric imaging of proteolytic activity, and force spectroscopy applications of single molecules or individual cells. To achieve a more complete understanding of the processes underlying the interaction of cells with their environments, the combination of AFM force spectroscopy experiments will be essential.

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Section: Force Mappingmentioning

confidence: 99%

Section: Force Mappingmentioning

confidence: 99%

Section: Force Mappingmentioning

confidence: 99%

See 1 more Smart Citation

Probing cellular microenvironments and tissue remodeling by atomic force microscopy

Ludwig

Kirmse

Poole

et al. 2007

Pflugers Arch - Eur J Physiol

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“…14 AFM was performed in fluid using a Nanoscope III Multimode-AFM (Digital Instruments, Santa Barbara, Calif) with a J-type scanner (maximal scan area:100ϫ100 m). V-shape oxide-sharpened cantilevers with spring constants of 0.06 N/m (Digital Instruments) were used for scanning in fluid.…”

Section: Afm Cell Volume Measurementsmentioning

confidence: 99%

Human Endothelium: Target for Aldosterone

et al. 2004

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Abstract-Aldosterone has long been known to control water and electrolyte balance by acting on mineralocorticoid receptors in kidney. However, recent studies demonstrated the presence of these receptors in nonclassical locations, including the cardiovascular system. We tested the hypothesis whether endothelial cells respond to aldosterone with changes in cell volume, a measure for ion-mediated water movement across the cell membrane. By means of atomic force microscopy in fluid, we measured volume of adherent human umbilical venous endothelial cells exposed for 72 hours to 10 nmol/L aldosterone. Over this period of time, cells swell by Ϸ18%. Aldosterone-induced swelling is prevented by 100 nmol/L of the mineralocorticoid receptor antagonist spironolactone, added to the primary endothelial cell culture. Aldosterone-treated cells dramatically shrink when 1 mol/L of the diuretic amiloride is applied. Cells deprived of aldosterone do not respond to amiloride. Our conclusions are: (1) aldosterone leads to sustained cell swelling inhibited by administration of spironolactone or the sodium channel blocker amiloride; (2) cells respond to amiloride after aldosterone exposure; (3) renal diuretics act on endothelial cells; and (4) Key Words: endothelium Ⅲ mineralocorticoids T he kidney is known to be the major target for aldosterone, a mineralocorticoid hormone synthesized in the adrenal cortex that acts on electrolyte transport in the distal nephron. 1 However, there is strong evidence that this hormone is also synthesized in heart 2 and blood vessels. 3 At these locations, it is regulated by similar mechanisms comparable to the renin-angiotensin aldosterone system. 4,5 Because of the fact that aldosterone acts on cardiomyocytes, cardiac fibroblasts, and endothelial cells, this hormone plays a major role in the development of heart failure, myocardial fibrosis, and endothelial dysfunction. 6 Moreover, there is much interest in the possibility of the use of aldosterone receptor blockade in patients to diminish pathological effects that can be produced by this hormone. 7 A study applying atomic force microscopy (AFM) on living aortic endothelial cells showed transient cell swelling that occurred over minutes and that was prevented by a high dose of amiloride known to inhibit plasma membrane Na ϩ /H ϩ exchange. 8 Although the underlying mechanism and its physiological relevance were still unclear, attention was placed on data suggesting that endothelial cells not only synthesize aldosterone 3 but also express mineralocorticoid receptors 9 and the epithelial sodium channel. 10 In a recent article, we applied cariporide, a specific Na ϩ /H ϩ exchange inhibitor, to human umbilical venous endothelial cells (HUVECs). 11 To our surprise, we found that the specific Na ϩ /H ϩ exchange inhibitor did not prevent aldosterone-induced cell swelling, whereas, in contrast, a low dose of amiloride known to block plasma membrane sodium channels was most effective. Taken together, these observations indicated that aldosterone triggers the "c...

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“…Importantly, detailed topographical surface scans are obtained, allowing the quantification of the roughness of any rippled surface. Moreover, AFM is an excellent tool to quantify the volume of cells adherent to a nondeformable surface under in vivo conditions and independent of the morphology of the cells [50]. Many AFM studies were performed on endothelial cells fixed with glutaraldehyde, as image quality generally is higher with fixed cells [18,17].…”

Section: Aldosteronementioning

confidence: 99%

How steroid hormones act on the endothelium—insights by atomic force microscopy

Hillebrand

Hausberg

Lang

et al. 2008

Pflugers Arch - Eur J Physiol

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Vascular actions of steroid hormones have gained increasing importance. Indeed, some steroid hormones favorably influence vascular structure and function, whereas others are detrimental. This review will focus on the endothelial effects of steroid hormones. In the first part, we summarize data from in vivo studies elucidating the regulation of endothelial function by steroid hormones. Accumulating data argue for an improvement of endothelium-derived relaxation and impaired vascular contraction by estradiol, whereas testosterone, progesterone, and aldosterone have contrary effects. In the second part, we present data from novel atomic force microscopy studies performed in living endothelial cells under the influence of steroid hormones. These studies provide insight into structural and functional alterations of endothelial cells characterized by changes in volume, apical surface, and stiffness. We summarize the available evidence that changes in shape of endothelial cells translate into changes of endothelial cell stiffness. Under the influence of estradiol, endothelial cells become spherical with consecutive improvement of elasticity, whereas aldosterone flattens endothelial cell-shape leading to increased stiffness. Both, endothelial cell shape and stiffness are major determinants of endothelial nitric oxide production. These studies emphasize the great potential of atomic force microscopy to investigate the function of living endothelial cells.Keywords Aldosterone . Glucocorticoids . Sex hormones . Atomic force microscopy . Endothelium . Imaging . Nitric oxideResearch over the last two decades has been clearly demonstrating that the vascular endothelium is a target for steroid hormones, e.g., sex hormones, glucocorticoids, and mineralocorticoids [25,35]. Indeed, specific receptors for these steroid hormones have been identified in endothelial cells. Numerous clinical studies demonstrate that the various steroid hormones affect vascular function in different ways. Sex hormonesVascular endothelial cells and vascular smooth muscle cells express receptors for estradiol, progesterone, and testosterone [54,55,66]. The sex hormones bind to specific cytosolic receptors. The resulting complexes are transported into the nucleus and initiate gene transcription (so-called genomic effects). Moreover, sex hormones cause a number of rapid non-genomic effects on vascular endothelial and smooth muscle cells.Several studies report gender differences in vascular function. Vascular contraction was found to be greater in male and ovarectomized female rats than in castrated male and female rats, suggesting an effect of testosterone in favor of vascular contraction and an effect of estradiol in favor of preventing vascular contraction [24]. Specifically, estradiol has been shown to cause endothelium-mediated vasorelaxation, whereas testosterone and progesterone interfere with estradiol-mediated endothelium-dependent vasodilation [25].There is a body of evidence suggesting that sex hormones interfere with the synthesis and b...

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Shape and Volume of Living Aldosterone-Sensitive Cells Imaged with the Atomic Force Microscope

Cited by 22 publications

References 36 publications

Probing cellular microenvironments and tissue remodeling by atomic force microscopy

Probing cellular microenvironments and tissue remodeling by atomic force microscopy

Human Endothelium: Target for Aldosterone

How steroid hormones act on the endothelium—insights by atomic force microscopy

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