Muc5b and Muc5ac are the major oligomeric mucins in equine airway mucus.
Abstract: Horses frequently suffer from respiratory diseases, which, irrespective of etiology, are often associated with airway mucus accumulation. Studies on human airways have shown that the key structural components of the mucus layer are oligomeric mucins, which can undergo changes of expression and properties in disease. However, there is little information on these gel-forming glycoproteins in horse airways mucus. Therefore, the aims of this study were to isolate equine airways oligomeric mucins, characterize their macromolecular properties, and identify their gene products. To this end, pooled tracheal washes, collected from healthy horses and horses suffering from respiratory diseases, were solubilized with 6 M guanidinium chloride (GdmCl). The oligomeric mucins were purified by density gradient centrifugation followed by size exclusion chromatography. Biochemical and biophysical analyses showed the mucins were stiffened random coils in solution that were polydisperse in size (M(r) = 6-20 MDa, average M(r) = 14 MDa) and comprised of disulfide-linked subunits (average M(r) = 7 MDa). Agarose gel electrophoresis showed that the pooled mucus sample contained at least two populations of oligomeric mucins. Electrospray ionization tandem mass spectrometry of tryptic digests of the unfractionated mucin preparation showed that the oligomeric mucins Muc5b and Muc5ac were present. In summary, we have shown that equine airways mucus is a mixture of Muc5b and Muc5ac mucins that have a similar macromolecular organization to their human counterparts. This study will form the basis for future studies to analyze the contribution of these two mucins to equine airways pathology associated with mucus accumulation.
Publication Date: 2007-02-09 PubMed ID: 17293373DOI: 10.1152/ajplung.00444.2006Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study investigates the main structural components (Muc5b and Muc5ac) of airway mucus in horses, with a focus on how they relate to the occurrence of respiratory diseases.
Introduction to the Study
- The study touched on a well-known issue in equine health where horses frequently suffer from respiratory diseases that often lead to the accumulation of airway mucus. These critical structural components in the mucus layer are oligomeric mucins.
- Prior to this study, there was limited information on these gel-forming glycoproteins (oligomeric mucins) in horse’s respiratory mucus.
- Therefore, the study’s primary intent was to isolate these oligomeric mucins from equine airways, understand their macromolecular properties, and identify their gene products.
Methodology
- The researchers gathered tracheal washes from both healthy horses and horses suffering from respiratory diseases.
- These samples were then treated with 6 M guanidinium chloride (GdmCl) to dissolve and extract the mucins.
- The process of purification involved density gradient centrifugation followed by size exclusion chromatography.
- The subsequent biochemical and physical examinations found that the mucins were stiffened random coils in the solution, varying in size, and composed of disulphide-linked subunits.
Results
- The agarose gel electrophoresis of the pooled mucus samples revealed that it contained at least two populations of oligomeric mucins.
- The study also used electrospray ionization tandem mass spectrometry on the mucins obtained in their initial form. The findings showed the presence of oligomeric mucins Muc5b and Muc5ac.
Conclusion
- The findings of the study reiterated that mucus in equine airways consisted of a mix of Muc5b and Muc5ac mucins. These exhibit a similar macromolecular organization to human mucins.
- This research is expected to form the foundation for future investigations aimed at analyzing the contribution of these two mucins to respiratory complications linked to mucus accumulation in equine airways.
Cite This Article
APA
Rousseau K, Kirkham S, McKane S, Newton R, Clegg P, Thornton DJ.
(2007).
Muc5b and Muc5ac are the major oligomeric mucins in equine airway mucus.
Am J Physiol Lung Cell Mol Physiol, 292(6), L1396-L1404.
https://doi.org/10.1152/ajplung.00444.2006 Publication
Researcher Affiliations
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
MeSH Terms
- Amino Acid Sequence
- Animals
- Horses / genetics
- Horses / metabolism
- Molecular Sequence Data
- Molecular Weight
- Mucin 5AC
- Mucin-2
- Mucin-5B
- Mucins / chemistry
- Mucins / genetics
- Mucins / metabolism
- Mucus / chemistry
- Mucus / metabolism
- Trachea / physiology
Citations
This article has been cited 18 times.- Karagianni AE, Eaton SL, Kurian D, Cillán-Garcia E, Twynam-Perkins J, Raper A, Wishart TM, Pirie RS. Application across species of a one health approach to liquid sample handling for respiratory based -omics analysis. Sci Rep 2021 Jul 12;11(1):14292.
- Atanasova KR, Reznikov LR. Strategies for measuring airway mucus and mucins. Respir Res 2019 Nov 21;20(1):261.
- Shears RK, Bancroft AJ, Hughes GW, Grencis RK, Thornton DJ. Extracellular vesicles induce protective immunity against Trichuris muris. Parasite Immunol 2018 Jul;40(7):e12536.
- Melo-Gonzalez F, Fenton TM, Forss C, Smedley C, Goenka A, MacDonald AS, Thornton DJ, Travis MA. Intestinal mucin activates human dendritic cells and IL-8 production in a glycan-specific manner. J Biol Chem 2018 Jun 1;293(22):8543-8553.
- Shears RK, Bancroft AJ, Sharpe C, Grencis RK, Thornton DJ. Vaccination Against Whipworm: Identification of Potential Immunogenic Proteins in Trichuris muris Excretory/Secretory Material. Sci Rep 2018 Mar 14;8(1):4508.
- Corfield A. Eukaryotic protein glycosylation: a primer for histochemists and cell biologists. Histochem Cell Biol 2017 Feb;147(2):119-147.
- Dickey BF, Fahy JV, Kesimer M, Boucher RC, Evans CM, Thornton D. Measuring Airway Mucin 2 in Patients with Severe Chronic Obstructive Pulmonary Disease with Bacterial Colonization. Ann Am Thorac Soc 2016 Nov;13(11):2103-2104.
- Duncan GA, Jung J, Hanes J, Suk JS. The Mucus Barrier to Inhaled Gene Therapy. Mol Ther 2016 Dec;24(12):2043-2053.
- Li X, Xu L, Li J, Li B, Bai X, Strauss JF 3rd, Zhang Z, Wang H. Otitis media in sperm-associated antigen 6 (Spag6)-deficient mice. PLoS One 2014;9(11):e112879.
- Davies HS, Pudney PD, Georgiades P, Waigh TA, Hodson NW, Ridley CE, Blanch EW, Thornton DJ. Reorganisation of the salivary mucin network by dietary components: insights from green tea polyphenols. PLoS One 2014;9(9):e108372.
- Tian C, Yu H, Yang B, Han F, Zheng Y, Bartels CF, Schelling D, Arnold JE, Scacheri PC, Zheng QY. Otitis media in a new mouse model for CHARGE syndrome with a deletion in the Chd7 gene. PLoS One 2012;7(4):e34944.
- Rousseau K, Cardwell JM, Humphrey E, Newton R, Knight D, Clegg P, Thornton DJ. Muc5b is the major polymeric mucin in mucus from thoroughbred horses with and without airway mucus accumulation. PLoS One 2011;6(5):e19678.
- Preciado D, Goyal S, Rahimi M, Watson AM, Brown KJ, Hathout Y, Rose MC. MUC5B Is the predominant mucin glycoprotein in chronic otitis media fluid. Pediatr Res 2010 Sep;68(3):231-6.
- Schwab UE, Fulcher ML, Randell SH, Flaminio MJ, Russell DG. Equine bronchial epithelial cells differentiate into ciliated and mucus producing cells in vitro. In Vitro Cell Dev Biol Anim 2010 Feb;46(2):102-6.
- Bartenschlager F, Kuropka B, Schmitz P, Dumke F, Landmann K, Gruber AD, Weise C, Schnabel CL, Gehlen H, Mundhenk L. Proteomic profiling of equine airway mucus reveals compositional changes in asthmatic phenotypes. Sci Rep 2026 Feb 10;16(1):5880.
- Kanesalingam T, Weiand E, Cann PM, Masen M, Ewen JP. A Coarse-Grained MARTINI Model for Mucins. J Chem Theory Comput 2026 Jan 13;22(1):723-737.
- Saleem W, Aslam A, Tariq M, Nauwynck H. Intestinal mucus: the unsung hero in the battle against viral gastroenteritis. Gut Pathog 2025 Feb 19;17(1):11.
- Lee DF, Everest DJ, Cooley W, Chambers MA. Investigation of nasal epithelial cells as a surrogate for bronchial epithelial cells in the research of equine asthma. PLoS One 2023;18(11):e0293956.
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