scholarly journals Electron microscopy characterization of minerals formed in vitro by human bone cells and vascular smooth muscle cells

2019 ◽  
Author(s):  
Elena Tsolaki ◽  
Louis Didierlaurent ◽  
Eike Müller ◽  
Markus Rottmar ◽  
Najma Latif ◽  
...  

AbstractSoft tissue mineralization has been found to be a major component of diseases such as aortic valve stenosis and rheumatic heart disease. Cardiovascular mineralization has been suggested to follow mechanisms similar to those of bone formation with several cell culture models been developed over the years to provide mechanistic insights. These cell models have been characterized by a wide range of biochemical and molecular methods, which identified the presence of osteogenic markers and bone-like cells. However, there is a surprisingly small number of studies where the mineral formed in these cell culture models has been characterized by physico-chemical methods, and even fewer studies have compared this mineral to the one produced by bone cells in cultures. Here we investigated the morphology and composition of the minerals formed in cell cultures of vascular smooth muscle cells and bone cells. Electron microscopy and traditional cell mineralization assays were applied, revealing that vascular cells are indeed able to form calcified nodules of elemental composition similar to bone, however with different morphology. Comparison of morphologies of the two minerals to that found in cardiovascular tissue shows that some of tissue calcification resembles the calcified fibers produced by bone cells in vitro. These results suggest that the characterization of the mineral is of utmost importance and its morphology and chemical properties can contribute an important piece of information in the comprehensive analysis of soft tissue mineralization mechanisms, both in in vitro cell culture as well as in clinical samples.

2008 ◽  
Vol 97 (12) ◽  
pp. 5158-5175 ◽  
Author(s):  
Winfried Neuhaus ◽  
Verena E. Plattner ◽  
Michael Wirth ◽  
Bettina Germann ◽  
Bodo Lachmann ◽  
...  

2006 ◽  
Vol 26 (17) ◽  
pp. 6425-6434 ◽  
Author(s):  
O. Jameel Shah ◽  
Tony Hunter

ABSTRACT The TSC1-TSC2/Rheb/Raptor-mTOR/S6K1 cell growth cassette has recently been shown to regulate cell autonomous insulin and insulin-like growth factor I (IGF-I) sensitivity by transducing a negative feedback signal that targets insulin receptor substrates 1 and 2 (IRS1 and -2). Using two cell culture models of the familial hamartoma syndrome, tuberous sclerosis, we show here that Raptor-mTOR and S6K1 are required for phosphorylation of IRS1 at a subset of serine residues frequently associated with insulin resistance, including S307, S312, S527, S616, and S636 (of human IRS1). Using loss- and gain-of-function S6K1 constructs, we demonstrate a requirement for the catalytic activity of S6K1 in both direct and indirect regulation of IRS1 serine phosphorylation. S6K1 phosphorylates IRS1 in vitro on multiple residues showing strong preference for RXRXXS/T over S/T,P sites. IRS1 is preferentially depleted from the high-speed pellet fraction in TSC1/2-deficient mouse embryo fibroblasts or in HEK293/293T cells overexpressing Rheb. These studies suggest that, through serine phosphorylation, Raptor-mTOR and S6K1 cell autonomously promote the depletion of IRS1 from specific intracellular pools in pathological states of insulin and IGF-I resistance and thus potentially in lesions associated with tuberous sclerosis.


2018 ◽  
Vol 97 (4) ◽  
pp. e632-e640 ◽  
Author(s):  
Miltiadis Fiorentzis ◽  
Periklis Katopodis ◽  
Helen Kalirai ◽  
Berthold Seitz ◽  
Arne Viestenz ◽  
...  

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Pirmin H. Lakner ◽  
Michael G. Monaghan ◽  
Yvonne Möller ◽  
Monilola A. Olayioye ◽  
Katja Schenke-Layland

2016 ◽  
Vol 36 (5) ◽  
pp. 862-890 ◽  
Author(s):  
Hans C Helms ◽  
N Joan Abbott ◽  
Malgorzata Burek ◽  
Romeo Cecchelli ◽  
Pierre-Olivier Couraud ◽  
...  

The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic components of plasma and xenobiotics. This “blood-brain barrier” function is a major hindrance for drug uptake into the brain parenchyma. Cell culture models, based on either primary cells or immortalized brain endothelial cell lines, have been developed, in order to facilitate in vitro studies of drug transport to the brain and studies of endothelial cell biology and pathophysiology. In this review, we aim to give an overview of established in vitro blood–brain barrier models with a focus on their validation regarding a set of well-established blood–brain barrier characteristics. As an ideal cell culture model of the blood–brain barrier is yet to be developed, we also aim to give an overview of the advantages and drawbacks of the different models described.


Nanotoxicity ◽  
2009 ◽  
pp. 379-395 ◽  
Author(s):  
Fabian Blank ◽  
Peter Gehr ◽  
Barbara Rothen-Rutishauser

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