scholarly journals The Roles of Insulin-Like Growth Factors in Mesenchymal Stem Cell Niche

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Amer Youssef ◽  
Doaa Aboalola ◽  
Victor K. M. Han

Many tissues contain adult mesenchymal stem cells (MSCs), which may be used in tissue regeneration therapies. However, the MSC availability in most tissues is limited which demands expansion in vitro following isolation. Like many developing cells, the state of MSCs is affected by the surrounding microenvironment, and mimicking this natural microenvironment that supports multipotent or differentiated state in vivo is essential to understand for the successful use of MSC in regenerative therapies. Many researchers are, therefore, optimizing cell culture conditions in vitro by altering growth factors, extracellular matrices, chemicals, oxygen tension, and surrounding pH to enhance stem cells self-renewal or differentiation. Insulin-like growth factors (IGFs) system has been demonstrated to play an important role in stem cell biology to either promote proliferation and self-renewal or enhance differentiation onset and outcome, depending on the cell culture conditions. In this review, we will describe the importance of IGFs, IGF-1 and IGF-2, in development and in the MSC niche and how they affect the pluripotency or differentiation towards multiple lineages of the three germ layers.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4046-4046 ◽  
Author(s):  
Michael Cross ◽  
Rudiger Alt ◽  
Lydia Schnapke-Hille ◽  
Thomas Riemer ◽  
Dietger Niederwieser

Abstract The hematopoietic stem cell niche presents a localised environment supporting the balanced maintenance, self-renewal and occasional expansion of the stem cell pool. These options are widely assumed to be regulated exclusively by signalling from specific combinations of stroma-bound or soluble ligands. However, a consideration of the rare conditions under which absolute numbers of stem cells increase in vivo as well as the selective pressures acting on regenerative systems during evolution has led us to propose a metabolic component to the stem cell niche which serves to limit cumulative damage, to avoid the selection of potentially oncogenic mutations and to tie symmetric division to slow proliferation. This would mean that traditional cell culture media based on “systemic” substrates such as glucose and glutamine may actively prevent the symmetric amplification of high quality stem cells, offering a possible explanation for the limited success in this area to date. To investigate this possibility, we have examined the effects of range of carbon and energy sources on the proliferation and maintenance of stem and progenitor cells. Our strategy is to screen a wide variety of culture conditions using murine FDCPmix cells, which are non-tumorigenic but have an innate tendency to amplify symmetrically in the presence of IL-3, and then to test key observations in human UCB CD133+ cells provided with SCF, TPO and FLT-3L. In both cell systems, we do indeed find an unusually low requirement for the systemic substrates glucose and glutamine normally included as major energy and carbon sources in cell culture media. Reducing glucose reduces the yield of committed cells from CD133+ cultures without affecting the accumulation of CD133+CD34+cKit+ progenitors. When provided with alternative substrates more likely to reflect a “niche” type environment, FDCPmix cells can be maintained for long periods in media containing only the trace levels of glucose or glutamine derived from dialysed serum, and show improved self-renewal under these conditions. We have also found that raising osmolarity reduces glucose dependence and simultaneously favours the maintenance both of self-renewing CFU (FDCPmix culture) and of CAFCweek13 (CD133+ culture). In parallel, the use of NMR and mass spectrometry techniques to profile intracellular metabolites in self-renewing and differentiating FDCPmix cells reveals a shift in the metabolite balance indicating reduced glycolysis in the early cells. Taken together, these results suggest that hematopoietic stem cells do indeed have remarkable metabolic characteristics consistent with adaptation to a metabolically limiting niche environment. It may therefore be necessary to identify niche substrates and to combine these with the relevant signalling environment in vitro in order to effectively increase stem cell numbers for research, stem cell transplantation and tissue engineering applications.


Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Johanne D. Cashman ◽  
Connie J. Eaves

Self-renewal is considered to be the essential defining property of a stem cell. Retroviral marking, in vitro amplification, and serial transplantation of human cells that can sustain long-term lymphomyelopoiesis in vivo have provided evidence that human hematopoietic stem cell self-renewal occurs both in vitro and in vivo. To investigate whether this process can be manipulated by cytokines, we administered two different combinations of human growth factors to sublethally irradiated nonobese diabetic/severe combined immunodeficient (SCID) mice transplanted with 107 light-density human cord blood cells and then performed secondary transplants to compare the number of transplantable human lymphomyeloid reconstituting cells present 4 to 6 weeks post-transplant. A 2-week course of Steel factor + interleukin (IL)-3 + granulocyte-macrophage colony-stimulating factor + erythropoietin (3 times per week just before sacrifice) specifically and significantly enhanced the numbers of transplantable human lymphomyeloid stem cells detectable in the primary mice (by a factor of 10). Steel factor + Flt3-ligand + IL-6 (using either the same schedule or administered daily until sacrifice 4 weeks post-transplant) gave a threefold enhancement of this population. These effects were obtained at a time when the regenerating human progenitor populations in such primary mice are known to be maximally cycling even in the absence of growth factor administration suggesting that the underlying mechanism may reflect an ability of these growth factors to alter the probability of differentiation of stem cells stimulated to proliferate in vivo.


Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Johanne D. Cashman ◽  
Connie J. Eaves

Abstract Self-renewal is considered to be the essential defining property of a stem cell. Retroviral marking, in vitro amplification, and serial transplantation of human cells that can sustain long-term lymphomyelopoiesis in vivo have provided evidence that human hematopoietic stem cell self-renewal occurs both in vitro and in vivo. To investigate whether this process can be manipulated by cytokines, we administered two different combinations of human growth factors to sublethally irradiated nonobese diabetic/severe combined immunodeficient (SCID) mice transplanted with 107 light-density human cord blood cells and then performed secondary transplants to compare the number of transplantable human lymphomyeloid reconstituting cells present 4 to 6 weeks post-transplant. A 2-week course of Steel factor + interleukin (IL)-3 + granulocyte-macrophage colony-stimulating factor + erythropoietin (3 times per week just before sacrifice) specifically and significantly enhanced the numbers of transplantable human lymphomyeloid stem cells detectable in the primary mice (by a factor of 10). Steel factor + Flt3-ligand + IL-6 (using either the same schedule or administered daily until sacrifice 4 weeks post-transplant) gave a threefold enhancement of this population. These effects were obtained at a time when the regenerating human progenitor populations in such primary mice are known to be maximally cycling even in the absence of growth factor administration suggesting that the underlying mechanism may reflect an ability of these growth factors to alter the probability of differentiation of stem cells stimulated to proliferate in vivo.


2019 ◽  
Vol 14 (3) ◽  
pp. 243-255 ◽  
Author(s):  
Glyn N Stacey ◽  
Peter W Andrews ◽  
Ivana Barbaric ◽  
Charlotta Boiers ◽  
Amit Chandra ◽  
...  

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