Discrete odors can selectively promote the neurogenesis of responsive olfactory sensory neuron subtypes

Core Concepts

Exposure to specific odors can selectively accelerate the birthrates of olfactory sensory neuron subtypes that are responsive to those odors.

Abstract

The content explores the relationship between olfactory stimulation and the neurogenesis of specific olfactory sensory neuron (OSN) subtypes in mammals. Key highlights:

Olfactory neurogenesis was previously thought to be a stochastic process, with newborn OSNs randomly expressing one of hundreds of possible odorant receptor (OR) genes. However, recent findings suggest that the birthrates of a subset of OSN subtypes are selectively reduced by olfactory deprivation.

The authors hypothesized that the neurogenic stimuli are specific odorants that selectively activate the same OSN subtypes whose birthrates are accelerated.

Using scRNA-seq and histological analyses, they found that exposure to male odors or the musk-like odorant muscone can selectively increase the quantities of newborn OSNs of subtypes responsive to these stimuli.

The stimulation-dependent changes in newborn OSN quantities were observed immediately after neurogenesis, suggesting they are mediated by altered birthrates rather than selective survival or OR switching.

The capacity for odor-induced increases in newborn OSN quantities of musk-responsive subtypes persisted into adulthood.

These findings indicate that olfactory neurogenesis serves an adaptive function, enabling the selective "amplification" of OSN subtypes in response to specific odor experiences.

Stats

Olfr235 OSNs exhibited a 2.3-fold greater representation on the open side compared to the closed side of the olfactory epithelium in UNO-treated male mice.
Olfr1440 OSNs exhibited a 1.8-fold greater representation on the open side compared to the closed side of the olfactory epithelium in UNO-treated male mice.
Olfr1431 OSNs exhibited a 2.5-fold greater representation on the open side compared to the closed side of the olfactory epithelium in UNO-treated male mice.
Exposure to 0.1% muscone increased the quantities of newborn Olfr235 OSNs by 3.1-fold in non-occluded female mice compared to unexposed females.
Exposure to 0.1% muscone increased the quantities of newborn Olfr1440 OSNs by 2.3-fold and newborn Olfr1431 OSNs by 1.6-fold in non-occluded female mice compared to unexposed females.

Quotes

"Exposure to male odors or the musk-like odorant muscone can selectively increase the quantities of newborn OSNs of subtypes responsive to these stimuli."
"The capacity for odor-induced increases in newborn OSN quantities of musk-responsive subtypes persisted into adulthood."
"These findings indicate that olfactory neurogenesis serves an adaptive function, enabling the selective "amplification" of OSN subtypes in response to specific odor experiences."

Key Insights Distilled From

In mice, discrete odors can selectively promote the neurogenesis of sensory neuron subtypes that they stimulate

by Hossain,K., ... at www.biorxiv.org 02-12-2024

https://www.biorxiv.org/content/10.1101/2024.02.10.579748v1

Deeper Inquiries

How might the selective amplification of specific OSN subtypes in response to odor exposure contribute to olfactory perception and behavior?

The selective amplification of specific olfactory sensory neuron (OSN) subtypes in response to odor exposure can have significant implications for olfactory perception and behavior. By increasing the representation of OSNs that are responsive to particular odorants, the olfactory system can become more sensitive and selective in detecting and discriminating between different smells. This heightened sensitivity can enhance the ability to detect specific odors in the environment, which is crucial for various behaviors such as finding food, avoiding predators, and social interactions. Additionally, the amplification of certain OSN subtypes can lead to a more refined and nuanced perception of complex odor mixtures, allowing for better odor recognition and interpretation. Overall, the selective amplification of specific OSN subtypes in response to odor exposure plays a vital role in shaping olfactory perception and guiding olfactory-driven behaviors.

What are the potential mechanisms by which chronic exposure to high concentrations of certain odorants could reduce the quantities of newborn OSNs of the responsive subtypes?

Chronic exposure to high concentrations of certain odorants can lead to a reduction in the quantities of newborn olfactory sensory neurons (OSNs) of the responsive subtypes through various mechanisms. One potential mechanism is through the induction of cellular stress and damage in the olfactory epithelium, which can impair the proliferation and differentiation of neural precursor cells, ultimately leading to a decrease in the production of new OSNs. High concentrations of odorants may also trigger apoptotic pathways in developing OSNs, causing cell death and reducing the overall numbers of newborn neurons. Additionally, prolonged exposure to strong odors can desensitize olfactory receptors, leading to a downregulation of receptor expression and a decrease in the responsiveness of OSNs to the specific odorants. This desensitization can result in a feedback loop where reduced activation of OSNs leads to further decreases in neurogenesis. Overall, chronic exposure to high concentrations of certain odorants can disrupt the normal process of neurogenesis in the olfactory system, leading to a reduction in the quantities of newborn OSNs of the responsive subtypes.

What other types of sensory stimuli, beyond olfaction, might selectively promote the neurogenesis of specific neuron subtypes in other sensory systems?

Beyond olfaction, various types of sensory stimuli can selectively promote the neurogenesis of specific neuron subtypes in other sensory systems. In the visual system, exposure to specific patterns of light or visual stimuli can enhance the generation of photoreceptor cells or specific types of retinal neurons. Auditory stimuli, such as specific frequencies or patterns of sound, can promote the neurogenesis of auditory sensory neurons in the cochlea or auditory cortex. In the somatosensory system, tactile stimuli or mechanical forces applied to the skin or other sensory organs can stimulate the generation of specific types of sensory neurons. Additionally, in the gustatory system, exposure to different tastes or chemicals can influence the neurogenesis of taste receptor cells in the taste buds. Overall, various sensory stimuli can play a role in selectively promoting the neurogenesis of specific neuron subtypes in different sensory systems, contributing to the development and function of these systems.