Human immune cells made using pluripotent stem cells in world first

Dr. Andrew Elfanty (left) and Dr. Ed Stanley (right), Murdoch Children’s Research Institute in Melbourne, Australia

Our immune system is the first line of defense our bodies use to fight off infections and disease. One crucial component of this defense mechanism are lymphocytes, which are specialized cells that give rise to various kinds of immune cells, such as a T cell, designed to attack and destroy harmful foreign bodies. Problems in how certain immune cells are formed can lead to diseases such as leukemia and other immune system related disorders.

But how exactly do immune cells form early on in the body?

Dr. Andrew Elfanty and Dr. Ed Stanley at Murdoch Children’s Research Institute in Australia have reproduced and visualized a method in the laboratory used to create human immune cells from pluripotent stem cells, a kind of stem cell that can make virtually any kind of cell in the body. Not only can this unlock a better understanding of leukemia and other immune related diseases, it could potentially lead to a patient’s own skin cells being used to produce new cells for cancer immunotherapy or to test autoimmune disease therapies.

Dr. Elefanty and Dr. Stanley used genetic engineering and a unique way of growing stem cells to make this discovery.

As observed in this video, the team was able to engineer pluripotent stem cells to glow green when they expressed a specific protein found in early immune cells. These cells can be seen migrating along blood vessels outlined in red. These cells go on to populate the thymus, which as we discussed in an earlier blog, is an organ that is crucial in developing functional T cells.

In a press release from Murdoch Children’s Research Institute, Dr. Stanley talks about the important role these early immune cells might play.

“We think these early cells might be important for the correct maturation of the thymus, the organ that acts as a nursery for T-cells”

In addition to this, the team also isolated the green, glowing pluripotent stem cells and showed that they could be used for multiple immune cell types, including those necessary for shaping the development of the immune system as a whole.

In the same press release, Dr. Elefanty discusses the future direction that their research could lead to.

“Although a clinical application is likely still years away, we can use this new knowledge to test ideas about how diseases like childhood leukemia and type 1 diabetes develop. Understanding more about the steps these cells go through, and how we can more efficiently nudge them down a desired pathway, is going to be crucial to that process.”

The full results to this study were published in Nature Cell Biology.

How a see-through fish could one day lead to substitutes for bone marrow transplants

Human blood stem cells

For years researchers have struggled to create human blood stem cells in the lab. They have done it several times with animal models, but the human kind? Well, that’s proved a bit trickier. Now a CIRM-funded team at UC San Diego (UCSD) think they have cracked the code. And that would be great news for anyone who may ever need a bone marrow transplant.

Why are blood stem cells important? Well, they help create our red and white blood cells and platelets, critical elements in carrying oxygen to all our organs and fighting infections. They have also become one of the most important weapons we have to combat deadly diseases like leukemia and lymphoma. Unfortunately, today we depend on finding a perfect or near-perfect match to make bone marrow transplants as safe and effective as possible and without a perfect match many patients miss out. That’s why this news is so exciting.

Researchers at UCSD found that the process of creating new blood stem cells depends on the action of three molecules, not two as was previously thought.

Zebrafish

Here’s where it gets a bit complicated but stick with me. The team worked with zebrafish, which use the same method to create blood stem cells as people do but also have the advantage of being translucent, so you can watch what’s going on inside them as it happens.  They noticed that a molecule called Wnt9a touches down on a receptor called Fzd9b and brings along with it something called the epidermal growth factor receptor (EGFR). It’s the interaction of these three together that turns a stem cell into a blood cell.

In a news release, Stephanie Grainger, the first author of the study published in Nature Cell Biology, said this discovery could help lead to new ways to grow the cells in the lab.

“Previous attempts to develop blood stem cells in a laboratory dish have failed, and that may be in part because they didn’t take the interaction between EGFR and Wnt into account.”

If this new approach helps the team generate blood stem cells in the lab these could be used to create off-the-shelf blood stem cells, instead of bone marrow transplants, to treat people battling leukemia and/or lymphoma.

CIRM is also funding a number of other projects, several in clinical trials, that involve the use of blood stem cells. Those include treatments for: Beta Thalassemia; blood cancer; HIV/AIDS; and Severe Combined Immunodeficiency among others.

Meet the proteins that tell stem cells where to move and how

 

Protein word art

Word cloud art work which shows all the proteins identified by the researchers

The environment you grow up in can have a huge influence on how you turn out. That applies to people, and to stem cells too. Now a new study has identified 60 proteins that can have a big impact on how cells react to the world around them, and how they communicate with each other.

Just as it is easier for us to move across firm ground than it is to slosh our way through a soggy, muddy field, it’s easier for stem cells to move smoothly and quickly over a solid surface than over a soft, giving surface. This is particularly true for tumor cells, which move much faster on a hard surface than any other kind.

It’s not just speed that is affected by the kind of surface you place stem cells on. For example certain stem cells placed on a hard surface will specialize and turn into bone, whereas if you place those same cells on a very soft surface they will turn into nerve cells.

The problem is we didn’t know much about why that was the case, we didn’t understand the mechanism at play that caused those cells to behave that way.

Now we do.

A team at the University of Manchester in England tackled this problem by researching integrins; these are receptors that are responsible for cell-to-cell communication, cell growth and function. Integrins are typically found at the surfaces and edges of cells and provide proteins with a convenient place to hang out when they interact with the world around them.

The researchers looked at 2400 examples of these integrin-protein clusters and, using mass spectrometry, narrowed their search down to 60 proteins that they identified as being essential in linking information from the integrins to the rest of the cellular world.

The work was published in Nature Cell Biology. In an accompanying news release Dr. Jon Humphries, one of the lead researchers, talked about the significance of the work:

“Understanding how cells sense their environment is an important step in understanding how, for example, cancer cells move or how stem cells take on different jobs.”

His colleague, Professor Martin Humphries, says understanding how cells sense where they are and how to behave gives us new insights into how we can use that knowledge to better control their movement:

“Our findings on how cells sense their environment have unlocked an important key to understanding how we can persuade cells to form different tissues and how we might stop cell movement in diseases such as cancer.”