Development of the Olfactory Epithelium and Nasal Glands in TMEM16A-/- and TMEM16A+/+ Mice

Abstract

TMEM16A/ANO1 is a calcium-activated chloride channel expressed in several types of epithelia and involved in various physiological processes, including proliferation and development. During mouse embryonic development, the expression of TMEM16A in the olfactory epithelium is dynamic. TMEM16A is expressed at the apical surface of the entire olfactory epithelium at embryonic day E12.5 while from E16.5 its expression is restricted to a region near the transition zone with the respiratory epithelium. To investigate whether TMEM16A plays a role in the development of the mouse olfactory epithelium, we obtained the first immunohistochemistry study comparing the morphological properties of the olfactory epithelium and nasal glands in TMEM16A-/- and TMEM16A+/+ littermate mice. A comparison between the expression of the olfactory marker protein and adenylyl cyclase III shows that genetic ablation of TMEM16A did not seem to affect the maturation of olfactory sensory neurons and their ciliary layer. As TMEM16A is expressed at the apical part of supporting cells and in their microvilli, we used ezrin and cytokeratin 8 as markers of microvilli and cell body of supporting cells, respectively, and found that morphology and development of supporting cells were similar in TMEM16A-/- and TMEM16A+/+ littermate mice. The average number of supporting cells, olfactory sensory neurons, horizontal and globose basal cells were not significantly different in the two types of mice. Moreover, we also observed that the morphology of Bowman’s glands, nasal septal glands and lateral nasal glands did not change in the absence of TMEM16A. Our results indicate that the development of mouse olfactory epithelium and nasal glands does not seem to be affected by the genetic ablation of TMEM16A.

The long tale of the calcium activated Cl−channels in olfactory transduction

“…60,[79][80][81] Only-TMEM16A and TMEM16F-were further studied by immunofluorescence and only the latter was shown to be expressed in the cilia of the OSNs, 80 while TMEM16A was expressed in some supporting cells of the OE. 82,83 Whether TMEM16F is part of the native channel requires further studies. 80,84 Four different splice variants of TMEM16B are expressed in the OE (Fig.…”

TMEM16A calcium-activated chloride currents in supporting cells of the mouse olfactory epithelium

“…Coronal sections of the olfactory epithelium and immunohistochemistry were obtained as previously described (Maurya and Menini, 2014; Maurya et al, 2015). Briefly, the dissected nose was fixed in 4% paraformaldehyde PBS for 4 h at 4°C.…”

“…Acute coronal slices of the olfactory epithelium of P0–P4 mice were prepared with slight modifications of the methods previously described to obtain slices of the vomeronasal organ (Shimazaki et al, 2006; Dibattista et al, 2008; Pietra et al, 2016; Wong et al, 2018). P0–P4 mice are suitable for this study, because TMEM16A is already expressed in the olfactory epithelium at this age (Maurya and Menini, 2014; Maurya et al, 2015). The nose of a P0–P4 mouse was dissected en bloc and embedded in 3% Type I-A agarose prepared in artificial cerebrospinal fluid (ACSF) once the solution cooled to 38°C.…”

“…We and others have recently shown that a relatively new discovered Ca 2+ -activated Cl − channel, TMEM16A, is expressed in olfactory supporting cells (Dauner et al, 2012; Maurya and Menini, 2014; Maurya et al, 2015). Interestingly, we found that TMEM16A expression is limited to supporting cells from a specific region of the olfactory epithelium (Maurya and Menini, 2014), although others, while confirming TMEM16A expression in the supporting cells, did not mention any zonal expression of the channel (Dauner et al, 2012).…”

Sustentacular Cell Enwrapment of Olfactory Receptor Neuronal Dendrites: An Update

“…Both the actin cytoskeleton and the ERM proteins play important roles not only in various epithelial cells, but also in the Schwann cells and oligodendroglia (in an event of myelination and/or formation of the node of Ranvier [60][61][62][63][64]). The ERMs are also abundantly expressed in the OSCs, especially at the apices and microvilli of OSCs [65].…”