Biomedical

Creating Induced Pluripotent Stem Cells. Is the problem in the miRNAs?

Induced pluripotent stem cells (IPSCs) are cells that have been transformed from their adult stage, so that they can be used as stem cells. They are made by introducing specific transcription factors into adult cells. They used to be very promising, and they still are, but since their first creation, there have been studies showing that creating IPSCs isn’t that simple and that those cells, while pluripotent, differ from naturally pluripotent stem cells like the ones found in small concentration in cord blood.

In certain applications, IPSCs have trouble integrating with the target tissue and differentiating. They do though help, by improving the extracellular environment with cytokines that reduce inflammation. But even then those cells can form teratomas and cause more harm than good.

Fortunately methods have improved a lot, and in the most recent studies, results seem very promising. A study in particular tried to find out whether miRNAs play a role in those defects with stem cell transplants. miRNAs, are small RNA molecules that affect the genome but do not code for any proteins. It has been shown, that such small pieces of RNA can be used as signals in the cell and they can be expressed under varying stimuli. When one is expressed it usually affects gene expression in a very small, mostly insignificant way. But a combination of those can make a significant difference in gene expression. This can lead to some issues.

Specifically, when pluripotent stem cells from other tissues, or especially induced pluripotent stem cells, are introduced into a new area in an adult body, they tend to overexpress some specific miRNAs and that can result in issues. A recent study showed that this overexpression of miRNAs may be what keeps cells from adequately and properly integrating to tissues after transplantation. The results show that while those miRNAs play no significant role in regulating epithelial-mesenchymal transition related transcription factors, there may be a difference caused by other miRNAs unrelated to epithelial-mesenchymal transition. This epithelial-mesenchymal transition, is a process that describes the movement and transformation of epithelial cells to become mesenchymal stem cells. This is an essential part of a humans early development, and those miRNAs work to keep this transformation going. But when we transplant IPSCs we don’t want them doing that. We want them attaching to the target tissue and differentiating, thus producing new healthy cells to replace old dying adult cells in whatever tissue we target. That’s the goal, to be able to put stem cells in any part of the body and have them integrate into tissues without any complications. Downregulating those miRNAs doesn’t help us reach that goal according to this study.

But, it is possible that other researchers may find that different miRNAs affect IPSCs in a more significant way. Once a combination of miRNAs whose overexpression keeps IPSCs from differentiating properly is found, we can attempt to make optimized IPSCs to treat patients without as many risks and with greater effectiveness. Since sequencing has become so easy, we may see soon, a study with positive results on miRNAs affecting IPSC performance.

Stem cell therapies have a definite place in the future of medicine, and treatments should be coming soon for tons of diseases. Once those get tested and once technologies improve, therapies will get cheaper and more accessible. To do so, we need more data, about every aspect of stem cells. Small RNAs have proven to affect cells a lot in recent studies, and those may be the answer to many stem cell limitations we face today.

If you are interested in stem cells leave a comment to let me know if i should keep you informed with more articles like this one. Also if you have any comments or tips let me know as well. Thank you for being here on Qul Mind and if you enjoy our site, make sure to follow on Facebook and Twitter.

Sources:

Pluripotent Stem Cell-Derived Hematopoietic Progenitors Are Unable to Downregulate Key Epithelial-Mesenchymal Transition-Associated miRNAs

Transplantation of undifferentiated murine embryonic stem cells in the heart: teratoma formation and immune response

iPSC-Derived Retina Transplants Improve Vision in rd1 End-Stage Retinal-Degeneration Mice

Image: http://www.publicdomainfiles.com/show_file.php?id=13984390217353

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