Endothelin as a neuroprotective factor in the olfactory epithelium

Area of Science:

• Neuroscience
• Cell Biology
• Olfactory System Research

Background:

• Olfactory sensory neurons (OSNs) are continuously renewed due to constant exposure to harsh environmental factors.
• The endothelin system, including endothelin-1 (ET-1), is present in the olfactory mucosa.
• OSNs primarily express ETB receptors, while ETA receptors are found on non-neuronal cells in the olfactory mucosa.

Purpose of the Study:

• To investigate the neuroprotective potential of the endothelin system on olfactory sensory neurons.
• To determine the specific roles of ETA and ETB receptors in mediating these effects.

Main Methods:

• Primary culture of olfactory sensory neurons on non-neuronal cells.
• Induction of apoptosis via serum deprivation.
• Treatment with endothelin-1 (ET-1).
• Assessment of neuronal survival and apoptosis markers (cleaved caspase-3, nuclear condensation).
• Analysis of olfactory epithelium in ETB-deficient rats.

Main Results:

• Serum deprivation significantly decreased OSN density in primary cultures.
• ET-1 treatment rescued a portion of OSNs, reducing apoptosis via both ETA and ETB receptors.
• ET-1's anti-apoptotic action was confirmed by reduced cleaved caspase-3 and nuclear condensation.
• ETB-deficient rats exhibited increased apoptosis in the olfactory epithelium.

Conclusions:

• Endothelin-1 (ET-1) acts as a direct anti-apoptotic factor for olfactory sensory neurons, primarily through ETB receptors.
• ET-1 indirectly supports OSN survival by limiting non-neuronal cell death via ETA receptors.
• The endothelin system plays a critical role in maintaining the integrity and survival of the olfactory epithelium.