title: Distinct presence of the tight junction protein claudin-3 in olfactory bulb and fila olfactoria of the mouse.
abstract: The tight junction protein claudin-3 is overexpressed in diverse epithelial tumours and is associated with increased survival, progression and motility of tumour cells. Claudin-3 expression profiles are being increasingly used for diagnostic and prognostic tumour classification. Claudin-3 has been identified as a receptor for Clostridium perfringens enterotoxin, which is under consideration for selective lysis of claudin-3-expressing tumours, particularly brain metastases, and other translational medicine uses. However, the localization of claudin-3 in the brain has not been completely elucidated. While claudin-3 in brain tissue adjacent to claudin-3-expressing metastases had been excluded and low or undetectable levels proposed in the CNS, under physiological conditions, in adult human, rat and mouse brains, claudin-3 was exclusively found in choroid plexus epithelium where it is considered an integral component of the blood-cerebrospinal-fluid barrier. We report here the pronounced presence of claudin-3 not only in the nasal region (as described for rat), but also in the mouse olfactory bulb and nerve using immunohistochemistry and Western blot. Claudin-3 was present in the fila olfactoria from the epithelium to the olfactory nerve and in the main and accessory olfactory bulb. We propose that the abundant presence of claudin-3 in the olfactory system, particularly in nerve fibres and the olfactory bulb cone, which we present here, may play a role at the interface of the central and peripheral nervous system, both as barrier and for axonal growth and communication. Thus, claudin-3 should be considered and further explored with regards to treatment approaches addressing the olfactory bulb and nasal region.
authors.affiliation: Department of Biomedicine, University of Basel, Basel, Switzerland. elisabeth.eppler@unibas.ch.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Eppler
authors.affiliation: Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Müller-Gerbl
authors.affiliation: Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: I Piotr
authors.initials: IP
authors.lastname: Maly
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000378:metabolism; D062445:Claudin-1 / Q000378:metabolism; D062446:Claudin-2 / Q000378:metabolism; D062465:Claudin-3 / Q000378:metabolism*; D062506:Claudin-4 / Q000378:metabolism; D062507:Claudin-5 / Q000378:metabolism; D004768:Enterotoxins / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D009297:Nasal Mucosa / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D009830:Olfactory Bulb / Q000378:metabolism*; D009832:Olfactory Nerve / Q000378:metabolism; D012903:Smell; D019108:Tight Junctions / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D062445:Claudin-1; D062446:Claudin-2; D062465:Claudin-3; D062506:Claudin-4; D062507:Claudin-5; D004768:Enterotoxins; C035598:enterotoxin, Clostridium