Signaling Molecule Important for the Skin’s Immune Cells

Signaling Molecule Important for the Skin’s Immune Cells

The skin harbors a complex and distinctive system that protects against varied pathologies, like infection and cancer. Although several of the mechanisms of immune activation within the skin have been investigated, it is likewise vital to uncover the immune-regulatory parts that limit effective immunity or prevent autoimmunity.

A signaling molecule known as Axl has been discovered in immune cells of the epidermis. This recently revealed findings provide new access into the evolution of necessary skin immune cells called Langerhans cells.

Langerhans cells, found within the epidermis, are a crucial part of the immune system. They are exist in all layers of the stratum, but are most prominently in the stratum spinosum. They can be found in other tissues also.

Langerhans cells work by ingesting antigens that get into the skin and present them to immune system cells that fight them off. In skin infections, the local Langerhans cells take up and process microbial antigens to become totally useful antigen-presenting cells.

As the scientific research, funded by the Austrian Science Fund FWF, also found, the natural production of the signaling molecule Axl is very dependent on the messenger substance TGF-beta1. Together, these findings offer a stronger understanding of how immune cells develop and provide new approaches for the treatment of autoimmune diseases.

Some infections can really “get underneath your skin”. Luckily, this is not always the case, because the skin has protection ability against infections – with the help of skin cells, called the Langerhans cells. These immune cells are found within the outer layer of the skin, the epidermis and supply a primary line of defence against invading viruses, bacteria and fungi. Researchers at the Medical University of Vienna is examining how immune cells develop from haemopoietic or blood-forming stem cells, and recently created some important findings in the process.

Cell signaling

[frame src=”” width=”250″ height=”200″ alt=”Stem Cells” align=”right”]Cell signaling is an element of a sophisticated system of communication that governs basic cellular activities and coordinates cell actions. The power of cells to understand and properly answer to their icroenvironment is the ground for development, tissue repair, and immunity. Mistakes in cellular signaling are responsible for diseases like cancer. By understanding cell signaling, diseases may be treated properly and artificial tissues may be created.

A team from the Institute of Immunology has not only demonstrated that a messenger molecule called Axl occurs on the surface of LCs, but also how this method is controlled by the signaling substance or cytokine transforming growth factor beta 1.

Commenting on the importance of this data, researchers explain that there are: “A large amount of benign microbes are found on the skin, that are vital for human health. The power to differentiate “good” from “bad” is thus of crucial importance for the LCs – and Axl molecules play an important role during this process.”

Axl belongs to the TAM receptor tyrosine kinase, whose members perform as inhibitors of innate inflammatory responses in nerve fiber cells and are crucial to the prevention of lupus-like autoimmunity. Finding proof for when and how Axl is made is very important for understanding the development of LCs from stem cells.

The researchers found that Axl is only produced in cells that go on to differentiate into LCs – and not in precursors that develop into other cell types. They also succeeded in determining that Axl is the only receptor of the TAM family synthesized under these conditions.

The significance of the findings of this Austrian Science Fund FWF project extends far beyond the elemental insights they supply into the development of skin immune cells. Axl´s ability to recognize the contrast between “good” and “bad” allows it to prevent autoimmune diseases. As a result, these findings could contribute to the treatment of those diseases in the future.

Reference: The Journal of Experimental Medicine Published October 15, 2012 // JEM vol. 209 no. 11 2033-2047 – Identification of Axl as a downstream effector of TGF-β1 during Langerhans cell differentiation and epidermal homeostasis