Featured Research

from universities, journals, and other organizations

Research could help people with declining sense of smell

Date:
December 9, 2011
Source:
University of California - Berkeley
Summary:
Cells in the nose – smell sensors, primarily – are constantly replaced as old ones die off. Olfactory stem cells are the source for these new cells, but how do they determine when to form mature cells? Neuroscientists have now found a genetic trigger – a transcription factor – that acts as a brake on differentiation. Removing it makes stem cells change into mature olfactory cells at the expense of self-renewal.

Elongated green cells are sensory neurons – which sense smells and relay that information to the brain – that originated from olfactory stem cells in the nose. Cells labeled in red are immature cells in the process of differentiating into neurons and other mature cell types.
Credit: Photomicrograph by Russell Fletcher, UC Berkeley

University of California, Berkeley, neuroscientists have discovered a genetic trigger that makes the nose renew its smell sensors, providing hope for new therapies for people who have lost their sense of smell due to trauma or old age.

The gene tells olfactory stem cells ‑ the adult tissue stem cells in the nose ‑ to mature into the sensory neurons that detect odors and relay that information to the brain.

"Anosmia ‑ the absence of smell ‑ is a vastly underappreciated public health problem in our aging population. Many people lose the will to eat, which can lead to malnutrition, because the ability to taste depends on our sense of smell, which often declines with age," said lead researcher and campus neuroscientist John Ngai.

"One reason may be that as a person ages, the olfactory stem cells age and are less able to replace mature cells, or maybe they are just depleted," he said. "So, if we had a way to promote active stem cell self-renewal, we might be better able to replace these lost cells and maintain sensory function."

Gary K. Beauchamp, director of the Monell Chemical Senses Center in Philadelphia, who was not a member of the research team, noted that the olfactory system stands out for its ability to regenerate following injury or certain diseases

"This new paper … presents an elegant analysis of some of the underlying genetic mechanisms regulating this regeneration," Beauchamp said. "It also provides important insights that should eventually allow clinicians to enhance regeneration, induce it in cases where, for currently unknown reasons, olfactory loss appears permanent, or even prevent functional loss as a person ages."

The discovery may also help scientists harness olfactory stem cells and stem cells found in other sensory systems more generally, to recover sensory function following injury or degenerative disease, said Ngai, the Coates Family Professor of Neuroscience in UC Berkeley's Department of Molecular and Cell Biology and director of the Helen Wills Neuroscience Institute and the QB3 Functional Genomics Laboratory.

Ngai, post-doctoral fellow Russell B. Fletcher and their UC Berkeley colleagues report their findings in the Dec. 8 issue of the journal Neuron.

Self-renewal or differentiation

In the nose, smell sensory neurons live only about 30 days, then are replaced by new cells. The new cells are generated by adult stem cells in the olfactory epithelium. A key question, Ngai said, is what tells the stem cells to divide into new ones ‑ a process called self-renewal ‑ or to mature, or differentiate, into fully functional sensory nerve cells and other cells critical to maintaining olfactory function.

"These stem cells are capable of reconstituting the entire sensory epithelium of the nose following injury," Ngai said, "so understanding how these stem cells work is important for understanding the regeneration process that goes on in the nose."

Fletcher and Ngai screened nose epithelial cells for regulatory genes and discovered one, called p63, that was a previously known transcription factor that acts by controlling the transcription of other regulatory genes in epithelial stem cells, such as those in the skin, the lining of the airways and the prostate. By knocking out the p63 gene in mice, they showed that nasal olfactory stem cells rapidly differentiated into sensory neurons at the expense of the stem cells themselves.

"This gene produces a molecule that is like a brake on the stem cell," Fletcher said. "When the brake is on, stem cells self-renew. If you remove the brake, the stem cells go into differentiation."

A drug that regulates p63, or modulates one of the genes that p63, in turn, regulates, might be able to boost the number of nasal stem cells as well as the number that mature into smell neurons.

Because p63 is found in many epithelial tissues, Ngai noted, these findings could be applied to other adult tissue stem cells ‑ including stem cells in the skin ‑ and possibly lead to future therapeutic "cell replacement" strategies to take the place of damaged or dead cells not only in the nervous system but in other epihelial tissues in the body.

Coauthors with Ngai and Russell are former graduate student Melanie S. Prasol, graduate student Jose Estrada, staff professionals Ariane Baudhuin and Yoon Gi Choi, and the late Karen Vranizan of UC Berkeley's Functional Genomics Laboratory.

The research is funded by the National Institute on Deafness and Other Communication Disorders of the National Institutes of Health, UC Berkeley's Siebel Stem Cell Institute, the California Institute of Regenerative Medicine and the National Science Foundation.


Story Source:

The above story is based on materials provided by University of California - Berkeley. The original article was written by Robert Sanders. Note: Materials may be edited for content and length.


Journal Reference:

  1. Russell B. Fletcher, Melanie S. Prasol, Jose Estrada, Ariane Baudhuin, Karen Vranizan, Yoon Gi Choi, John Ngai 72(5) pp. 748 - 759. p63 Regulates Olfactory Stem Cell Self-Renewal and Differentiation. Neuron 72(5) pp. 748 - 759, 72(5) pp. 748 - 759; 8 December 2011 DOI: 10.1016/j.neuron.2011.09.009

Cite This Page:

University of California - Berkeley. "Research could help people with declining sense of smell." ScienceDaily. ScienceDaily, 9 December 2011. <www.sciencedaily.com/releases/2011/12/111207132649.htm>.
University of California - Berkeley. (2011, December 9). Research could help people with declining sense of smell. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2011/12/111207132649.htm
University of California - Berkeley. "Research could help people with declining sense of smell." ScienceDaily. www.sciencedaily.com/releases/2011/12/111207132649.htm (accessed August 20, 2014).

Share This




More Health & Medicine News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: World's Oldest Man Lives in Japan

Raw: World's Oldest Man Lives in Japan

AP (Aug. 20, 2014) A 111-year-old Japanese was certified as the world's oldest man by Guinness World Records on Wednesday. Sakari Momoi, a native of Fukushima in northern Japan, was given a certificate at a hospital in Tokyo. (Aug. 20) Video provided by AP
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Freetown a City on Edge

Ebola-Hit Sierra Leone's Freetown a City on Edge

AFP (Aug. 19, 2014) Residents of Sierra Leone's capital voice their fears as the Ebola virus sweeps through west Africa. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
101-Year-Old Working Man Has All The Advice You Need

101-Year-Old Working Man Has All The Advice You Need

Newsy (Aug. 19, 2014) Herman Goldman has worked at the same lighting store for almost 75 years. Find out his secrets to a happy, productive life. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
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