Skin Releases Enzymes That Ignore Bacteria to Prevent Constant Inflammation

The skin protects the body from external dangers, such as bacteria and viruses. Despite being only a few millimeters thick, it is still the heaviest and largest organ that makes up one-seventh of the entire body weight.

The skin could weigh up to 7.5 and 22 pounds (3.5 and 10 kilograms) and has a surface area of 1.5 to 2 square meters. That means that skin is extremely important for the body and metabolism.

So, how is the skin being protected from environmental factors that may cause skin inflammation?

Enzymes Ignore Bacteria To Prevent Constant Skin Inflammation

The study, "Cutaneous innate immune tolerance is mediated by epigenetic control of MAP2K3 by HDAC8/9" published in Science Immunology, showed how the body regulates and prevents constant skin inflammation. It identified two enzymes responsible for protecting the skin and the body from potential microbial intruders.

Researchers from the UC San Diego School of Medicine identified histone deacetylases (HDACs) enzymes that inhibit the inflammatory response of the skin. Similarly, researchers from the Mount Sinai Hospital have identified HDAC3 as an essential enzyme for proper skin development and barrier formation, Science Daily reported.

Scientists noted that these enzymes act on the chromosome of specific skin cells that provide immune tolerance by the skin. "Without these enzymes telling our cells to ignore certain bacteria, we'd have a constant rash on our skin," said Professor Richard Gallo, MD, Ph.D., according to UC San Diego's news release.

Researchers said that the epigenetic control of gene expression explains the mechanism for how the environment can interact and alter cell function. Within the cells are proteins called toll-like receptors (TLR) that trigger an inflammatory response to threats.

However, scientists identified HDAC8 and HDAC9 enzymes to counter TLR as these two enzymes inhibit the inflammatory response. Researchers said that skin inflammatory response could be controlled by targeting these enzymes since this epigenetic change is reversible, unlike the DNA.

New Way of Skin Immune Regulation

According to Devicourse, the researchers first studied mouse models in which they identified HDAC8 and HDAC9 had been genetically knocked out.

The skin of the mice had lost its ability to tolerate microbial and viral exposures that resulted in a heightened immune reaction. They reproduced their results with human cells to find how it can be translated to human skin. They found that in human skin it means having to suffer from constant skin inflammation.

But Dr. Gallo believes that their study could help change how doctors treat certain types of skin inflammation or other skin problems. He noted that their work gives a completely new way to think about skin immune regulation.

"Through alterations in HDAC activity, we've provided a possible way to explore and quiet down unnecessary inflammation by working with skin cells themselves. In the future, drugs designed to turn these enzymes on or off could help treat skin disease as an alternative to antibiotics," he said in the university's news release.