New study reveals bitter taste receptors regulate the upper respiratory defense system

Findings could help uncover novel diagnostic tools and treatments for patients with chronic sinus conditions

2012-10-08

(Press-News.org) PHILADELPHIA – A new study from a team of researchers at the Perelman School of Medicine at the University of Pennsylvania, the Monell Chemical Senses Center, and the Philadelphia VA Medical Center, reveals that a person's ability to taste certain bitter flavors is directly related to their ability to fight off upper respiratory tract infections, specifically chronic sinus infections. The new research is published in the latest edition of the Journal of Clinical Investigation.

Most humans experience five types of tastes: sweet, salty, sour, bitter, and savory. The sense of taste is mediated by taste receptor cells which are bundled in our taste buds. "Sour" and "bitter" taste sensations alert the body to harmful foods that have spoiled or are toxic. But based on genetics, up to 25 percent of the population cannot detect certain bitter flavors (non-tasters), 25 percent can detect exceedingly small quantities (super-tasters), and the rest of us fall somewhere between these two extremes.

So what exactly does drinking a cup of bitter coffee have to do with chronic sinus infections, which account for approximately 18-22 million physician visits in the U.S. each year? Recent investigations have shown that these taste receptors (known as T2Rs) are also found in both upper and lower human respiratory tissue, likely signaling a connection between activation of bitter tastes and the need to launch an immune response in these areas when they are exposed to potentially harmful bacteria and viruses.

"With this information in mind, we wanted to better understand the exact role that bitter taste receptors play in the upper airway, especially between these super and non-tasters," says Noam Cohen, MD, PhD, assistant professor of Otorhinolaryngology: Head and Neck Surgery, staff physician at the Philadelphia VAMC, and senior author of the new study.

Cohen and his colleagues formulated the following hypotheses around the connection: (1) bitter taste receptors are functional in the nose (upper respiratory tract), and each receptor detects a specific type of bacteria; (2) upon activation by a specific bacterial product, the bitter taste receptor initiates a local defensive response to combat the attacking bacteria; and (3) genetic variability of the bitter taste receptors alters the vigorousness of the response, thus leaving certain individuals with very strong defenses and others with weak defenses against a specific bacteria.

To test these hypotheses, the team grew cell cultures from sinus and nasal tissue samples collected during sinus surgical procedures. These cultures develop cilia, produce mucus, and reflect many of the defensive workings found inside the nose and sinuses.

They found that one of the bitter taste receptors that functions in upper airway cells, known as T2R38, acts as a type of "security guard" for the upper airway by detecting molecules that a certain class of bacteria secretes. "These molecules instruct other bacteria to form a biofilm, which helps harbor the bacteria. From previous work, we know that these biofilms spur the immune system to mount an over-exuberant inflammatory response that can lead to sinusitis symptoms. When the T2R38 receptor detects these molecules, it activates local defensive maneuvers to increase mucus clearance and kill the invading bacteria. It's really like modern warfare – intercept the enemies' early communications to thwart their plans and win the battle," Cohen said.

Through the cultures, the research team demonstrated that super-tasters detect very small concentrations of the offending molecules, while non-tasters and the middle-ground individuals require 100 times more of the molecule for detection. The research team also examined the patients that the original sinus tissue samples were collected from. They found that none of the super tasters were infected with the specific type of bacteria that are detected by the T2R38 receptor, known as a gram-negative bacteria.

"Based on these findings, we believe that other bitter taste receptors in the airway perform the same "guard duty" function for early detection of attack by different types of bacteria, and we hope to translate these findings into personalized diagnostics for patients with chronic rhinosinusitis," Cohen says.

The research team is also using the results of the current study to develop a simple "taste-test" protocol to be conducted during clinic visits. "We're optimistic that a test of this nature will help us predict who is at risk to develop biofilms based on their ability to taste various bitter compounds. Additionally, we are looking at therapeutic outcomes, both surgical and medical, based on the taster/non-taster genetic status to determine whether knowing this status will stratify patients to either surgical or medical interventions."

### Other study authors from Penn include Robert J. Lee (first author), Jennifer M. Kofonow, Bei Chen, Laurel Doghramji, Nithin D. Adappa, James N. Palmer, David W. Kennedy, Paschalis-Thomas Doulias, and Harry Ischiropoulos.

Funding for the study came from the Flight Attendants Medical Research Institute 082478 (NAC), and a philanthropic contribution from the RLG Foundation, Inc. (NAC), as well as several grants from the National Institute on Deafness and Other Communication Disorders to the Monell collaborators.

Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4.3 billion enterprise.

The Perelman School of Medicine is currently ranked #2 in U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $479.3 million awarded in the 2011 fiscal year.

The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania -- recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; and Pennsylvania Hospital — the nation's first hospital, founded in 1751. Penn Medicine also includes additional patient care facilities and services throughout the Philadelphia region.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2011, Penn Medicine provided $854 million to benefit our community.

ELSE PRESS RELEASES FROM THIS DATE:

Study finds nearly 50% of retail firewood infested with insects

2012-10-08

A new study published in the Journal of Economic Entomology reports that live insects were found in 47% of firewood bundles purchased from big box stores, gas stations and grocery stores in Colorado, New Mexico, Utah and Wyoming. Untreated firewood can harbor pathogens and destructive insects such as the emerald ash borer, the Asian longhorned beetle, bark beetles and others, and transport them to uninfested areas. Furthermore, the risk of moving insects in untreated firewood is high, the authors found, because insects emerged up to 558 days from the purchase date of ...

Smallest and fastest-known RNA switches provide new drug targets

2012-10-08

ANN ARBOR, Mich.—A University of Michigan biophysical chemist and his colleagues have discovered the smallest and fastest-known molecular switches made of RNA, the chemical cousin of DNA. The researchers say these rare, fleeting structures are prime targets for the development of new antiviral and antibiotic drugs. Once believed to merely store and relay genetic information, RNA is now known to be a cellular Swiss Army knife of sorts, performing a wide variety of tasks and morphing into myriad shapes. Over the past decade, researchers have determined that most of the ...

Breathe in, breathe out: New way of imaging lungs could improve COPD diagnosis and treatment

2012-10-08

ANN ARBOR, Mich. — A new approach to lung scanning could improve the diagnosis and treatment of a lung disease that affects approximately 24 million Americans and is the country's third-highest cause of death. In a new paper published online in Nature Medicine, a team from the University of Michigan Medical School reports on a technique called parametric response mapping, or PRM. They used PRM to analyze computed tomography, or CT, scans of the lungs of patients with chronic obstructive pulmonary disease, known as COPD, who took part in the national COPDGene study funded ...

UCLA researchers discover that the sleeping brain behaves as if it's remembering something

2012-10-08

UCLA researchers have for the first time measured the activity of a brain region known to be involved in learning, memory and Alzheimer's disease during sleep. They discovered that this part of the brain behaves as if it's remembering something, even under anesthesia, a finding that counters conventional theories about memory consolidation during sleep. The research team simultaneously measured the activity of single neurons from multiple parts of the brain involved in memory formation. The technique allowed them to determine which brain region was activating other areas ...

Genome-wide study identifies 8 new susceptibility loci for atopic dermatitis

2012-10-08

Researchers at the RIKEN Center for Genomic Medicine (CGM) and their colleagues have identified 8 new loci associated with susceptibility to atopic dermatitis in the Japanese population. The findings, which appear in the journal Nature Genetics, advance our understanding of the genetic basis of the skin disorder, which affects millions of children and adults around the world. Atopic dermatitis (often called ecszema) is a chronic, relapsing inflammatory skin condition affecting as much as one-fifth of children and 1-3% of adults in industrialized countries. Those with ...

Discovery of gatekeeper nerve cells explains the effect of nicotine on learning and memory

2012-10-08

Swedish researchers at Uppsala University have, together with Brazilian collaborators, discovered a new group of nerve cells that regulate processes of learning and memory. These cells act as gatekeepers and carry a receptor for nicotine, which can explain our ability to remember and sort information. The discovery of the gatekeeper cells, which are part of a memory network together with several other nerve cells in the hippocampus, reveal new fundamental knowledge about learning and memory. The study is published today in Nature Neuroscience. The hippocampus is an ...

Stanford researchers show oil palm plantations are clearing carbon-rich tropical forests in Borneo

2012-10-08

Expanding production of palm oil, a common ingredient in processed foods, soaps and personal care products, is driving rainforest destruction and massive carbon dioxide emissions, according to a new study led by researchers at Stanford and Yale universities. The study, published online Oct. 7 in the journal Nature Climate Change, shows that deforestation for the development of oil palm plantations in Indonesian Borneo is becoming a globally significant source of carbon dioxide emissions. Plantation expansion is projected to contribute more than 558 million metric tons ...

A novel oncogenic network specific to liver cancer initiation

2012-10-08

Researchers headed by Erwin Wagner, the Director of the BBVA Foundation-CNIO Cancer Cell Biology Programme at the Spanish National Cancer Research Centre (CNIO), have deciphered how a stress-inducible gene regulator, AP-1, controls the survival of liver tumor-initiating cells. These results, published in the online edition of Nature Cell Biology, could provide new preventive strategies and identify potentially targetable molecules to prevent liver cancer. Hepatocellular carcinoma (HCC) causes more than 500,000 deaths per year worldwide. While patients with chronic hepatitis ...

Gene variant linked with reduced lung cancer risk

2012-10-08

A variant in a gene involved with inflammation and the immune response is linked with a decreased risk of lung cancer. That is the finding of an analysis published early online in CANCER, a peer-reviewed journal of the American Cancer Society. The results add to the growing body of literature implicating these processes in the development of lung cancer. Meredith Shiels, PhD, MHS and Anil Chaturvedi, PhD, of the National Cancer Institute in Rockville, MD, and their colleagues analyzed 1,429 variants in inflammation- and immunity-related genes from 378 patients with lung ...

Patient navigation leads to faster diagnosis for breast cancer, according to new study

2012-10-08

WASHINGTON, D.C. –Today researchers from The George Washington University published a study showing that breast cancer patients can reduce potentially dangerous delays in the identification of breast cancer with the assistance of patient navigation services. Patient navigation—a service that helps patients overcome barriers to getting health care, including setting up appointments, dealing with health insurance, and helping with fears about cancer—led to a nearly four-fold reduction in the time it took to diagnose a suspicious breast lump, the new study found. "The time ...

LAST 30 PRESS RELEASES:

Insilico Medicine announces developmental candidate benchmarks and timelines for novel therapeutics discovered using generative AI

A wealth of evidence: PIK compiles 85,000 individual studies about climate policy

New fish species with ‘face paint’ named after Studio Ghibli character

Mechanical heart valve replacements have better long-term survival, study finds

Sandra Diaz and Eduardo Brondízio, scholars of human-nature interconnection, win the 2025 Tyler Prize with call for policies, business models and individuals to recognize humanity’s 'entanglement' wit