Scientists Replicated Bacterial Homing Instinct in Stem Cells
We are not unknown with the fact that stem cells have huge applications, especially in the field of medical science. One such important application is curing heart disease by regenerating the damaged heart tissues using stem cells. Scientists at the University of Bristol (U.K) have taken this further by developing a new approach of homing stem cells to target site i.e. heart tissues by mimicking bacterial homing instinct.
Why this study is important?
Cardiac disease is one of the major causes of death among men and women across the globe. Severe condition like heart stroke and blockage causes damage to the heart tissues. With minimal regenerative property, heart muscles are unable to regain their existing strength and get replaced by scar tissues, this drastically impacts cardiac functioning. In order to overcome it, many trials have been carried out where stem cells from patient or donor were taken and introduced near heart tissues. This gave promising results where the damaged tissues regenerated into new.
But what was the challenge?
Though the results of stem cells based regenerative cell therapy were promising, there were significant challenges in targeting stem cells to heart tissues. It was observed that the high blood flow and tissue sinks within the circulatory system, causes most of the stem cells to land up into lungs and spleen.
Recently, for the first time in world scientists have discovered a new approach of homing stem cells to target heart tissue by using a protein.
What is the new approach?
In the present new approach, the scientists tried to modify the membrane of the stem cells by infusing or say painting it with a protein named adhesin.
There exist many bacteria which show the homing property, wherein they locate themselves to the diseased tissue. The most common example is oral bacteria causing strep throat found in our mouth. It is noted that if this bacteria gets into the bloodstream, it homes itself to the weak and damaged heart tissue leading to infectious endocarditis. Scientists at the University of Bristol studied the homing property of bacteria and replicated it into stem cells, targeting heart tissues.
Re-engineering cell membrane for homing
Cell membrane re-engineering is evolving as a massive new approach to introduce a molecule of interest into the plasma membrane. This improves the homing property of cells by driving them to the target site effectively.
In order to colonize, bacteria readily adhere to the surface of the host using adhesins protein. Adhesin is a special protein which recognizes and binds to specific domains and motifs present on the host surface. One such important domain with which adhesin interacts is fibronectin. It is a multidomain glycoprotein which has been found to be a major target of bacterial adhesins.
Scientists infused the fibronectin-binding domain of bacterial adhesin protein specific to the cardiac region on the plasma membrane of stem cells. Thus, giving the cells homing property observed in the bacteria. With this new approach, now therapeutic cells locate themselves more effectively near heart tissues rather than getting distributed to other organs like lungs and spleen.
The most novel part of the study is, for the first time scientists have used the homing property of infectious bacteria into mammalian cells.
Benefits of new homing mammalian stem cells
There are many reasons which make the new homing approach highly beneficial. Firstly, the insertion of adhesin on the surface of therapeutic cells causes no loss of the biological function of the protein. Secondly, the study showed that there were no cytotoxic effects. Third, there was absence of any hematologic response as well as a negligible increase of cell number in lungs and other organs.
The Homing approach paves the way for scientists to further investigate the process and extend its application to other diseases. The way homing instinct is applied to stem cells for the cardiac region, it can also be extended to other parts of the body like lungs, brain, kidney, liver and more.