L. Wang and E.A. Pawlak are equal first authors
Expression and Activity of Collagenases in the Digital Laminae of Horses with Carbohydrate Overload-Induced Acute Laminitis
Article first published online: 25 NOV 2013
Copyright © 2013 by the American College of Veterinary Internal Medicine.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Journal of Veterinary Internal Medicine
Volume 28, Issue 1, pages 215–222, January/February 2014
How to Cite
Wang, L., Pawlak, E.A., Johnson, P.J., Belknap, J.K., Alfandari, D. and Black, S.J. (2014), Expression and Activity of Collagenases in the Digital Laminae of Horses with Carbohydrate Overload-Induced Acute Laminitis. Journal of Veterinary Internal Medicine, 28: 215–222. doi: 10.1111/jvim.12252
- Issue published online: 15 JAN 2014
- Article first published online: 25 NOV 2013
- Manuscript Accepted: 17 OCT 2013
- Manuscript Revised: 31 JUL 2013
- Manuscript Received: 25 APR 2013
- Morris Animal Foundation. Grant Numbers: D08EQ-054, D13EQ-004
- USDA NRI CSREES. Grant Number: 35204-18313
- USDA CSREES to SJB. Grant Number: MAS00907
- Lotta Crabtree Fellowship
- NIH. Grant Number: DE016289
- Matrix metalloproteinases
Matrix metalloproteinases (MMP) are hypothesized to degrade structurally important components of the laminar extracellular matrix (ECM) in horses with laminitis.
To compare levels of expression of stromelysin-1 (MMP-3), collagenases (MMP-1, -13), and membrane type-MMPs (MMP-14, -15, -16), and the distribution of their ECM substrates, in laminae of healthy horses and horses with carbohydrate overload laminitis.
Twenty-five adult horses.
Gene and protein expression were determined in extracts of laminae using real-time quantitative polymerase chain reaction and Western blotting after sodium dodecylsulfate polyacrylamide gel electrophoresis. Distribution of MMP-13 and ECM components was determined using indirect immunofluorescent microscopy of nonfixed frozen sections. ECM morphology was assessed by hematoxylin and eosin staining.
Of the genes studied, only those encoding MMP-1 and -13 were upregulated in CHO-induced laminitis; MMP-1 at Obel grade (OG)1 lameness and MMP-13 at OG3 lameness. Laminar MMP-1 was present as 52 kDa proenzyme only. MMP-13 was present as pro- (61 kDa) and processed (48 kDa) enzyme. MMP-13 localized to the basal epithelium of the secondary epidermal laminae and its increased expression were accompanied by the appearance in secondary dermal laminae (SDL) of multiple foci that were devoid of collagen I, fibronectin, chondroitin and keratan sulfate glycosaminoglycans, and eosin-staining material.
Conclusions and Clinical Relevance
MMP-13 is upregulated in laminae of horses with CHO-induced OG3 lameness and, by degrading components of the ECM, may contribute to the formation of ECM-free lesions (gaps or tears) that appear in the SDL with OG3 lameness.