scholarly journals Intracellular label-free detection of mesenchymal stem cell metabolism within a perivascular niche-on-a-chip

2020 ◽  
Author(s):  
Simone Perottoni ◽  
Nuno G. B. Neto ◽  
Cesare Di Nitto ◽  
Manuela Teresa Raimondi ◽  
Michael G. Monaghan

AbstractThe stem cell niche at the perivascular space in human tissue plays a pivotal role in dictating the overall fate of stem cells within it. Mesenchymal stem cells (MSCs), in particular, experience influential microenvironmental conditions, which induce specific metabolic profiles that affect processes such as cell differentiation and dysregulation of the immunomodulatory funtion. Reports focusing specifically on the metabolic status of MSCs under the effect of pathophysiological stimuli - in terms of flow velocities, shear stresses or oxygen tension – do not model heterogenous gradients, highlighting the need of more advanced models reproducing the metabolic niche. Organ-on-a-chip technology offers the most advanced tools for stem cell niche modelling thus allowing for controlled dynamic culture conditions while profiling tunable oxygen tension gradients. However, current systems for live cell detection of metabolic activity inside microfluidic devices require the integration of microsensors that allow for extracellular measurments only, giving innacurate and indirect information about the metabolic state of cells. Here, we present a metabolic toolbox coupling a miniatuirzed in vitro system for human-MSCs dynamic culture, that mimics microenvironmental conditions of the perivascular niche, with high-resolution imaging of intracellular metabolism. Using Fluorescence Lifetime Imaging Microscopy (FLIM) we monitor the spatial metabolic machinery and correlate it with experimentally validated intracellular oxygen concentration after designing the oxygen tension decay along the fluidic chamber by in silico models prediction. Our platform allows for the subjection of a metabolic profile to MSCs, mimicking the physiological niche in space and time, and its real-time monitoring representing a functional tool for modelling perivascular niches, relevant diseases and metabolic-related uptake of pharmaceuticals.

2020 ◽  
Vol 71 (2) ◽  
pp. 211-213
Author(s):  
K. Sato ◽  
S. Chitose ◽  
K. Sato ◽  
F. Sato ◽  
T. Kurita ◽  
...  

2008 ◽  
Vol 8 ◽  
pp. 1168-1176 ◽  
Author(s):  
Laren Becker ◽  
Qin Huang ◽  
Hiroshi Mashimo

Lgr5 has recently been identified as a murine marker of intestinal stem cells. Its expression has not been well characterized in human gastrointestinal tissues, but has been reported in certain cancers. With the increasing appreciation for the role of cancer stem cells or tumor-initiating cells in certain tumors, we sought to explore the expression of Lgr5 in normal and premalignant human gastrointestinal tissues. Using standard immunostaining, we compared expression of Lgr5 in normal colon and small intestine vs. small intestinal and colonic adenomas and Barrett's esophagus. In the normal tissue, Lgr5 was expressed in the expected stem cell niche, at the base of crypts, as seen in mice. However, in premalignant lesions, Lgr5+cells were not restricted to the crypt base. Additionally, their overall numbers were increased. In colonic adenomas, Lgr5+cells were commonly found clustered at the luminal surface and rarely at the crypt base. Finally, we compared immunostaining of Lgr5 with that of CD133, a previously characterized marker for tumor-initiating cells in colon cancer, and found that they identified distinct subpopulations of cells that were in close proximity, but did not costain. Our findings suggest that (1) Lgr5 is a potential marker of intestinal stem cells in humans and (2) loss of restriction to the stem cell niche is an early event in the premalignant transformation of stem cells and may play a role in carcinogenesis.


2020 ◽  
Author(s):  
Lucía Benítez ◽  
Lucas Barberis ◽  
Luciano Vellón ◽  
Carlos Alberto Condat

Abstract Background: Cancer stem cells are important for the development of many solid tumors. These cells receive promoting and inhibitory signals that depend on the nature of their environment (their niche) and determine cell dynamics. Mechanical stresses are crucial to the initiation and interpretation of these signals. Methods: A two-population mathematical model of tumorsphere growth is used to interpret the results of a series of experiments recently carried out in Tianjin, China, and extract information about the intraspecific and interspecific interactions between cancer stem cell and differentiated cancer cell populations. Results: The model allows us to reconstruct the time evolution of the cancer stem cell fraction, which was not directly measured. We find that, in the presence of stem cell growth factors, the interspecific cooperation between cancer stem cells and differentiated cancer cells induces a positive feedback loop that determines growth, independently of substrate hardness. In a frustrated attempt to reconstitute the stem cell niche, the number of cancer stem cells increases continuously with a reproduction rate that is enhanced by a hard substrate. For growth on soft agar, intraspecific interactions are always inhibitory, but on hard agar the interactions between stem cells are collaborative while those between differentiated cells are strongly inhibitory. Evidence also suggests that a hard substrate brings about a large fraction of asymmetric stem cell divisions. In the absence of stem cell growth factors, the barrier to differentiation is broken and overall growth is faster, even if the stem cell number is conserved. Conclusions: Our interpretation of the experimental results validates the centrality of the concept of stem cell niche when tumor growth is fueled by cancer stem cells. Niche memory is found to be responsible for the characteristic population dynamics observed in tumorspheres. A specific condition for the growth of the cancer stem cell number is also obtained.


2011 ◽  
pp. 35-55 ◽  
Author(s):  
Yoshiko Matsumoto ◽  
Hiroko Iwasaki ◽  
Toshio Suda

Cancer Cell ◽  
2015 ◽  
Vol 28 (6) ◽  
pp. 800-814 ◽  
Author(s):  
Yoku Hayakawa ◽  
Hiroshi Ariyama ◽  
Jitka Stancikova ◽  
Kosuke Sakitani ◽  
Samuel Asfaha ◽  
...  

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