What you need to know about melanin, the new skin color that’s making us all thinner
NEW YORK — What makes melanin a natural color?
That’s the question researchers are grappling with after a major scientific study revealed that skin cells make melanin from sunlight and the surrounding environment.
But in the lab, the answer is still a mystery.
“The reason melanin is not a natural product is because it is derived from a complex, biologically-derived molecule,” said study author Jodi Osterholm, a postdoctoral fellow in dermatology at the University of Rochester.
Melanin is a natural pigment found in skin cells that provides color and strength.
It’s been known for a long time that melanin does have a role in regulating the appearance of skin.
However, what makes melanins different from natural pigments is that the pigment is produced by cells in the skin that are not able to synthesize melanin themselves.
When cells are not producing melanin itself, the skin is thin and uneven.
That unevenness can cause the skin to appear more oily, dark, wrinkled or darkened.
That unevenness is a function of the way the skin absorbs and passes the pigment from the melanin it makes to the skin’s surrounding tissue.
To understand how melanin works in the body, scientists had to look to the cells that make melanins in the first place.
The researchers studied the structure of melanin cells, which are made up of a single protein, melanin hydroxylase.
Normally, when a protein is produced in a cell, it converts a substance called an adenosine triphosphate (ATP) into a molecule called a reactive oxygen species (ROS).
When the protein is not in the cell, the adenosin triphos is broken down into its constituent components, such as adenosyl triphoglobulin (ATG) and adenosone triphopyranosyltransferase (ATPD).
Because the molecule can’t be synthesized in the laboratory, the body has to create melanin.
Researchers discovered that when the body produces melanin in a melanocyte, it uses a chemical called cyclic AMP, or aldolane, to turn it into a pigment that is easily absorbed by the skin.
When the body does not have the melanocyte’s production of melanins, the cell becomes a more efficient and stable pigment production system.
What does the study show?
The research showed that when a melanin-producing cell is exposed to sunlight, the protein that converts the melanine to a pigment called melanin becomes inactive and is replaced by an alternative protein called cytochrome P450-2A (CYP2A).
That enzyme, called a C-type lectin, acts as an intermediary to convert the pigment into a form that can be absorbed into the skin without producing any ROS.
The findings, published online on Jan. 12 in the journal Nature Biotechnology, were not expected.
There were a few limitations to the study.
The researchers could not prove that sunlight-induced melanin production is the sole reason that skin looks darker.
The study also did not establish that sunlight does indeed increase the amount of melanocytes.
But the researchers do know that the amount and rate of sunlight exposure that leads to the production of more melanin are related to the level of vitamin D.
“This study was able to demonstrate that sunlight is a major contributor to the increase in melanin synthesis, which could potentially lead to a greater skin barrier and the increase of melanocyte-specific pigmentation,” said Osterhams co-author, Rachel Breslin, a professor of dermatology and molecular genetics at New York University.
In addition, Osterheim and her colleagues found that the melanins they found in the study did not contain any of the genes that are normally associated with the production and maintenance of skin pigmentation.
These genes include melanin dehydrogenase (MDE), melanocortin-1 receptor (MCR1), and melanin decarboxylase (PDC).
The results also provide some new insights into the ways that melanins are produced in the human body.
While the researchers could only test the effect of sunlight on the skin of humans, they could not test the effects of melanosomes.
They found that melanosome-producing melanocytes are found in human skin, but melanosomal structures, such in the eyes, are not.
Osterholm said it’s important to realize that the effects on the body of sunlight-exposed skin cells are different than the effects in people with normal skin.
“The fact that the skin cells in people exposed to light can have higher melanin levels, suggests that there might be some difference in how melanocytes make melaninos, and that might be related to how they are distributed throughout the body,” Osterlund said.