Bodily Fluids Keep Us Alive, And Calcium Is Key To Their Secretion

Fluid
Many bodily fluids have to be secreted by certain glands to be useful. Pixabay Public Domain

Bodily secretions, though perhaps not the most charming part of biology, are the body’s unsung heroes. Saliva helps us break down and swallow our food, the pancreas creates digestive juices we need to break down nutrients, and various hormones regulate everything from body temperature to hunger. Exactly how these secretions are possible, though, has remained a mystery up until now. A group of researchers from the University Of Rochester Medical Center have identified a specific calcium process as the key to production of bodily secretions.

Researchers have known calcium is at the center of bodily secretions for years. When the mineral floods our cells, they open up channels necessary for the production and secretion of fluids like saliva. These gates won’t open if calcium doesn’t increase, an issue that occurs in patients with Sjögren's syndrome and other secretion-related diseases. Dr. David I. Yule has researched calcium’s role in Sjögren's for 15 years, and in his newest study answers a pressing question that scientists have been unable to answer: What is necessary for a significant calcium channel to open up and begin secretion processes?

Previous research has shown a protein called IP3 receptor must be present for calcium to increase and generate channels in many types of cells. The protein isn’t easy to understand, though: One channel can be created from four identical units on the IP3 receptor, but scientists weren’t sure how many of the units had to be engaged at once for the channel to work.

The team discovered, through advanced gene editing and molecular engineering techniques, that all four parts of the IP3 receptor must be activated for calcium to increase in the cell and begin secretion processes. This was true without exception, and Yule believes the feature ensures the calcium channel opens only under strict conditions, preventing unsavory events that could occur if the channel opened more easily — too much calcium can lead to cell death.

“This elegant study by Drs. Alzayady and Yule uses a very clever approach to definitively answer a long standing question in the calcium signaling and secretion fields,” said Dr. Robert T. Dirksen, chair of the pharmacology and physiology department at the University of Rochester in a statement. “The results have broad implications not only for how calcium is controlled in cells, but also for understanding various human secretory disorders that range from dry mouth to pancreatitis.”

Yule added that the team’s ultimate hope is that better knowledge of how calcium flow is controlled will help advance research on new treatments. Currently, Sjögren's disease has no treatment, and the associated dry mouth can lead to cavities, loss of teeth, and oral infections. Ongoing research at Yule’s lab is investigating how genetic diseases affecting IP3 can result in brain and immune system disorders.

Source: Yule D, Alzayady K, Wang L, Chandrasekhar R, Wagner L. The Science behind bodily secretions. Science Signaling. 2016.

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