Equine laminitis: membrane type matrix metalloproteinase-1 (MMP-14) is involved in acute phase onset.
BACKGROUND
Enzymatic separation at the hoof lamellar dermal-epidermal interface may play a role in the development of laminitis and characterising and locating matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of MMPs or TIMPs) in lamellar tissues may further understanding of pathogenesis.


OBJECTIVE
To clone and sequence the cDNA encoding lamellar MMP-14 and TIMP-2, and quantify their transcription in normal and laminitic tissue; and to develop antibody to locate MMP-14 in lamellar tissues.


METHODS
Tissue samples were obtained from an oligofructose induced model of laminitis. Total RNA was isolated, amplified by RT-PCR, cloned into a vector and sequenced. Real-time PCR was used to quantify MMP-14 and TIMP-2 expression. Rabbit anti-equine MMP-14 antibody was developed to analyse MMP-14 proteins from hoof tissues.


RESULTS
Immunohistochemistry detected MMP-14 in the cytoplasm of normal lamellar basal and parabasal cells in close proximity to the lamellar basement membrane. In laminitis affected tissue MMP-14 immunostaining was depleted in lamellar basal cells. Quantitative real-time PCR showed MMP-14 and TIMP-2 expression significantly (P<0.05) elevated and lowered respectively in laminitis affected tissues.


CONCLUSIONS
MMP-14, located in the cytoplasm of normal lamellar basal cells, disappears during laminitis development. The pathology of laminitis is associated with increased and lowered transcription of MMP-14 and TIMP-2, respectively.


CONCLUSIONS
Enzymes have a role in laminitis pathology and inhibition of their activity may prevent laminitis.
Kyaw-Tanner
M T
MT
Australian Equine Laminitis Research Unit, School of Veterinary Science, Faculty of Natural Resources Agriculture and Veterinary Science, The University of Queensland, Brisbane, Queensland 4072, Australia.
Wattle
O
O
van Eps
A W
AW
Pollitt
C C
CC
D000210:Acute-Phase Reaction / Q000201:enzymology / Q000473:pathology / Q000662:veterinary; D000818:Animals; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005534:Foot Diseases / Q000201:enzymology / Q000473:pathology / Q000662:veterinary*; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006724:Hoof and Claw / Q000201:enzymology / Q000473:pathology; D006734:Horse Diseases / Q000201:enzymology* / Q000473:pathology; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D007249:Inflammation / Q000201:enzymology / Q000473:pathology / Q000662:veterinary*; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D018076:DNA, Complementary; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D020781:Matrix Metalloproteinase 1; D053511:Matrix Metalloproteinase 14