Featured Research

from universities, journals, and other organizations

Lung Airway Cells Activate Vitamin D And Increase Immune Response

Date:
November 5, 2008
Source:
University of Iowa
Summary:
Essential to good health, vitamin D requires activation to function properly in the body. Until recently, this activation was thought to occur primarily in the kidneys. A new study finds it can occur in lung airway cells. The investigation also links the vitamin D produced in the lung airway cells to activation of infection-fighting genes.

Vitamin D is essential to good health but needs to be activated to function properly in the human body. Until recently, this activation was thought to happen primarily in the kidneys, but a new University of Iowa study finds that the activation step can also occur in lung airway cells.

The study also links the vitamin D locally produced in the lung airway cells to activation of two genes that help fight infection. The study results appear in the Nov. 15 issue of the Journal of Immunology, now online.

In addition to contributing to calcium absorption and bone health, vitamin D is increasingly recognized for its beneficial effects on the immune system. Vitamin D deficiency has been recently linked to increased risk of some infections, autoimmune diseases such as multiple sclerosis and type 1 diabetes, and some cancers.

"The more scientists have been studying vitamin D, the more we learn about new roles it plays in the human body," said the study's lead author Sif Hansdottir, M.D., fellow in internal medicine in the University of Iowa Carver College of Medicine. "The active form of vitamin D is known to affect the expression of more than 200 genes, so we were interested both in the possible lung-specific production of active vitamin D and in vitamin D-dependent production of proteins that fight infections."

The first step in vitamin D activation takes place in the liver, where an enzyme called 25-hydroxylase converts vitamin D into a "storage" form. The next step takes place typically in the kidneys, but in recent years, tissue and organs such as skin, intestines, breast and prostate have been found also to express the enzyme that completes vitamin D conversion.

The University of Iowa team, based in the laboratory of Gary Hunninghake, M.D., professor of internal medicine and the study's senior author, used cells from deceased human donors to demonstrate that the presence of the enzyme 1 alpha-hydroxylase in the airway cells helps convert the storage form of vitamin D into its active form.

"When we put the storage form of vitamin D on the lung airway cells, we saw them convert it to the active form," Hansdottir said. "The next step was to investigate whether this active form could affect the expression of genes."

The team then showed that vitamin D activated by airway cells affects two genes involved in immune defense. One gene expresses a protein called cathelicidin that can kill bacteria. The second gene, called CD14, produces a protein that helps cells recognize different kinds of pathogens that could be a threat.

"Vitamin D converted by the kidneys circulates in the bloodstream, but vitamin D converted by other organs appears to stay within those organs and protect them from infection," Hansdottir said. "We were able to see this happen in cells lining the trachea and main bronchi."

The team also found that when lung airway cells are infected by a virus, they express more of the enzyme that activates vitamin D. Hansdottir said the team is very interested in pursuing studies on the role of viral infections in vitamin D production and subsequent effects on lung infections.

"Vitamin D not only increases proteins involved in bacterial killing but also can dampen inflammation," Hansdottir said. "Controlling inflammation through vitamin D is good because too much inflammation can cause problems such as sepsis and seems to contribute to autoimmune disease."

Hansdottir noted that vitamin D insufficiencies and deficiencies (which are more severe) are fairly common, particularly for people living in northern latitudes. While vitamin D can be generated through sun exposure, such exposure is generally not recommended as a remedy because of skin cancer risks. Instead, supplements can be used.

The American Academy of Pediatrics recently recommended that the vitamin D dosage for children be increased to 400 IU (international units) per day. Optimal daily intake for adults is still being studied but may be as high as 800 to 1,000 IU.


Story Source:

The above story is based on materials provided by University of Iowa. Note: Materials may be edited for content and length.


Cite This Page:

University of Iowa. "Lung Airway Cells Activate Vitamin D And Increase Immune Response." ScienceDaily. ScienceDaily, 5 November 2008. <www.sciencedaily.com/releases/2008/11/081104080317.htm>.
University of Iowa. (2008, November 5). Lung Airway Cells Activate Vitamin D And Increase Immune Response. ScienceDaily. Retrieved August 31, 2014 from www.sciencedaily.com/releases/2008/11/081104080317.htm
University of Iowa. "Lung Airway Cells Activate Vitamin D And Increase Immune Response." ScienceDaily. www.sciencedaily.com/releases/2008/11/081104080317.htm (accessed August 31, 2014).

Share This




More Health & Medicine News

Sunday, August 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

Reuters - US Online Video (Aug. 30, 2014) California lawmakers pass a bill requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on campuses. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) Here are three things you need to know about the deadly Ebola outbreak's progression this week. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins