Several sensory systems, including vision and olfaction, rely on cilia-mediated sensory transduction. In vertebrates, olfactory sensory neurons located in the nasal cavity detect odors.
Cilia on olfactory sensory neurons are enriched for all necessary components for olfactory signal transduction. In zebrafish, each ciliated olfactory sensory neuron expresses one of over a 100 different olfactory receptors.
Odor response in zebrafish ciliated neurons
In collaboration with researchers at Harvard, Cameron Wyatt and Emre Yaksi studied the effect of cilia protein deficiency on sensory cilia function. The team combined live imaging of neuronal calcium activity with genetic manipulation to record the functional activity of cilia-dependent sensory neurons at single-cell resolution after stimulation with different classes of odorants.
Postdoctoral researcher Cameron Wyatt: "We saw that deficiencies in intra-flagellar transport (Ift) genes essential for ciliogenesis severely affected the cilia length and number in these olfactory neurons. Deficiency of either of the two transport genes we studied significantly reduced responses to bile acids, while the response to amino acids was not significantly changed.”
A role in disease
These insights into cilia biology may have clinical significance as mutations in genes encoding cilia proteins cause a class of complex genetic syndromes called ciliopathies.
Wyat: “These new findings on Ift mutation and knockdown implicate ift172-deficiency as a novel cause of reduced olfaction or hyposmia.”
Ciliopathy patients often present with hyposmia, and the new results support the idea that hyposmia can be used as a diagnostic indicator.
Judith Bergboer, Cameron Wyatt, Christina Austin‑Tse, Emre Yaksi & Iain A. Drummond. Assaying sensory ciliopathies using calcium biosensor expression in zebrafish ciliated olfactory neurons. Cilia 2018 7:2