A tickle in the nose can help trigger a sneeze, expelling irritants and disease-causing pathogens. But the cellular pathways that control the sneeze reflex go far beyond the sinuses and have been poorly understood. Now, a team of researchers has identified, in mice, specific cells and proteins that control the sneeze reflex.
"Better understanding what causes us to sneeze -- specifically how neurons behave in response to allergens and viruses -- may point to treatments capable of slowing the spread of infectious respiratory diseases via sneezes," said the study's senior investigator.
The findings are published in the journal Cell.
"We study the neural mechanism behind sneezing because so many people, including members of my own family, sneeze because of problems such as seasonal allergies and viral infections," said the author. "Our goal is to understand how neurons behave in response to allergies and viral infections, including how they contribute to itchy eyes, sneezing and other symptoms. Our recent studies have uncovered links between nerve cells and other systems that could help in the development of treatments for sneezing and for fighting infectious respiratory diseases."
Sneezing is the most forceful and common way to spread infectious droplets from respiratory infections. Scientists first identified a sneeze-evoking region in the central nervous system more than 20 years ago, but little has been understood regarding how the sneeze reflex works at the cellular and molecular level.
In the new study, the team established a mouse model in an attempt to identify which nerve cells send signals that make mice sneeze. The researchers exposed the mice to aerosolized droplets containing either histamine or capsaicin, a pungent compound made from chili peppers. Both elicited sneezes from the mice, as they do in people.
By examining nerve cells that already were known to react to capsaicin, the team was able to identify a class of small neurons linked to sneezing that was caused by that substance. The researchers then looked for molecules -- called neuropeptides -- that could transmit sneeze signals to those nerve cells, and found that a molecule called neuromedin B (NMB) was required for sneezing.
Conversely, when they eliminated the NMD-sensitive neurons in the part of the nervous system that evoked sneezes in the mice, they blocked the sneeze reflex. Those neurons all make a protein called the neuromedin B receptor. In mice without that receptor, sneezing again was greatly reduced.
"Interestingly, none of these sneeze-evoking neurons were housed in any of the known regions of the brainstem linked to breathing and respiration," the senior author said. "Although we found that sneeze-evoking cells are in a different region of the brain than the region that controls breathing, we also found that the cells in those two regions were directly connected via their axons, the wiring of nerve cells."
The researchers also found they could stimulate the sneeze reflex by exposing part of the mouse brain to the NMB peptide. Further, the animals began to sneeze even though they had not been exposed to any capsaicin, histamine or other allergens.
Because many viruses and other pathogens -- including the majority of human rhinoviruses and coronaviruses such as Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2, the coronavirus that causes COVID-19 -- are spread in part by aerosolized droplets, the authorsaid it may be possible to limit the spread of those pathogens by targeting NMB or its receptor to limit sneezing in those known to be infected.
"A sneeze can create 20,000 virus-containing droplets that can stay in the air for up to 10 minutes," the author explained. "By contrast, a cough produces closer to 3,000 droplets, or about the same number produced by talking for a few minutes. To prevent future viral outbreaks and help treat pathological sneezing caused by allergens, it will be important to understand the pathways that cause sneezing in order to block them. By identifying neurons that mediate the sneeze reflex, as well as neuropeptides that activate these neurons, we have discovered targets that could lead to treatments for pathological sneezing or strategies for limiting the spread of infections."
https://medicine.wustl.edu/news/what-happens-when-we-sneeze/
https://www.cell.com/cell/fulltext/S0092-8674(21)00634-6
A neuropeptide that trigger sneezing identified!
- 892 views
- Added
Edited
Latest News
Protein that helps COVID-19…
By newseditor
Posted 26 Jul
Spinal Muscular Atrophy (SM…
By newseditor
Posted 26 Jul
Link between bowel movement…
By newseditor
Posted 26 Jul
Inhibition of IL-11 signall…
By newseditor
Posted 25 Jul
Brain changes linked to obe…
By newseditor
Posted 25 Jul
Other Top Stories
'Natural killer' cells could halt Parkinson's progression
Read more
How inflammation triggers fatal cycle in Alzheimer's disease
Read more
A protein controls inflammation through non-enzymatic activities
Read more
Sex-specific traits of the immune system explain men's susceptibili…
Read more
Too much salt weakens the immune system and may increase infections
Read more
Protocols
A systems biology approach…
By newseditor
Posted 24 Jul
quantms: a cloud-based pipe…
By newseditor
Posted 22 Jul
Emerging tools and best pra…
By newseditor
Posted 19 Jul
Directly selecting cell-typ…
By newseditor
Posted 17 Jul
PUFFFIN: an ultra-bright, c…
By newseditor
Posted 16 Jul
Publications
Hepatocyte-intrinsic SMN de…
By newseditor
Posted 26 Jul
Aberrant bowel movement fre…
By newseditor
Posted 26 Jul
A pseudoautosomal glycosyla…
By newseditor
Posted 26 Jul
Microglia protect against a…
By newseditor
Posted 26 Jul
Rigor and reproducibility i…
By newseditor
Posted 26 Jul
Presentations
Myelin plasticity in the ve…
By newseditor
Posted 10 Jun
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar