Authors: Takeshi Matsunobu, Kimihiro Okubo, Minoru Gotoh, Ruby Pawankar, Joaquim Mullol.
It is known that pre-proendothelin (pre-proET) is a precursor of ET, and that first it is locally broken down to bigET-1 and further becomes ET-1 by means of endothelin converting enzyme. Investigations of pre-proET in epithelial cells were conducted for the purpose of studying its production, existence, and role in epithelial cells. Pre-proET mRNA was expressed in the nasal mucosal epithelial cells of all normal subjects, chronic sinusitis subjects, and allergic rhinitis subjects. Expression was observed in cultured nasal mucosal epithelial cells also. In combination with previous reports, it is suggested that material is produced in the pre-proET state in the nasal mucosa epithelial cells, that this becomes ET locally, and that it is being released within the cultured supernatant or within the nasal discharge. Furthermore, pre-proET mRNA expression was enhanced in the nasal mucosa epithelial layers as a result of antigen induction reactions as a result of house dust perennial nasal allergies. The degree of this enhancement correlated to the degree of antigen induction reaction. It was thought that pre-proET increased in response to antigen exposure in allergic nasal mucosa, and that it was modifying the allergic reaction. Investigation of the mechanism of pre-proET expression enhancement is needed in the future.
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