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Mucin genes in horse airways: MUC5AC, but not MUC2, may play a role in recurrent airway obstruction
Author(s) -
GERBER V.,
ROBINSON N. E.,
VENTA P. J.,
RAWSON J.,
JEFCOAT A. M.,
HOTCHKISS J. A.
Publication year - 2003
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/042516403776148291
Subject(s) - mucin , horse , mucin 2 , mucus , stomach , airway , biology , pathology , gene expression , respiratory tract , parenchyma , muc1 , gene , respiratory system , medicine , anatomy , genetics , biochemistry , paleontology , ecology , surgery
Summary Reasons for performing study : Increased mucin gene expression may be an important cause of mucus accumulation observed in recurrent airway obstruction (RAO)‐affected horses. To date, however, no mucin gene sequences are available for the horse. Objectives : To identify equine homologues of gel‐forming mucins and investigate their expression at different airway generations of healthy and RAO‐affected horses. Methods : Two equine homologues were identified by cloning and sequencing fragments of equine (eq)MUC5AC and eqMUC2. Results : Semiquantitative RT‐PCR on RNA from airways (generations 1, 5, 10, 15; small airways and parenchyma), stomach (glandular), and colon revealed that eqMUC5AC is expressed in equine stomach and in all of the airway samples. In contrast, eqMUC2 steady‐state mRNA levels were detected in colon and very faintly in stomach, but not in airway tissue. EqMUC5AC expression was also compared to that of ZO‐1, a tight junction protein, and eqMUC5AC/ZO‐1 ratios were higher in RAO‐affected compared to control horses at all airway generations. Conclusions : That eqMUC5AC is expressed in horse airways, but any expression of MUC2 is undetectable and unlikely to be of physiological consequence. Potential relevance : EqMUC5AC up‐regulation may be a primary mechanism responsible for mucus hypersecretion and accumulation in RAO.