Vena cava and aortic smooth muscle cells express transglutaminases 1 and 4 in addition to transglutaminase 2.
Transglutaminase (TG) function facilitates several vascular processes and diseases. Although many of these TG-dependent vascular processes have been ascribed to the function of TG2, TG2 knockout mice have a mild vascular phenotype. We hypothesized that TGs besides TG2 exist and function in the vasculature. Biotin-pentylamide incorporation, a measure of general TG activity, was similar in wild-type and TG2 knockout mouse aortae, and the general TG inhibitor cystamine reduced biotin-pentylamine incorporation to a greater extent than the TG2-specific inhibitor Z-DON, indicating the presence of other functional TGs. Additionally, 5-hydroxytryptamine-induced aortic contraction, a TG-activity-dependent process, was decreased to a greater extent by general TG inhibitors vs. Z-DON (maximum contraction: cystamine = abolished, monodansylcadaverine = 28.6 ± 14.9%, and Z-DON = 60.2 ± 15.2% vehicle), providing evidence for the importance of TG2-independent activity in the vasculature. TG1, TG2, TG4, and Factor XIII (FXIII) mRNA in rat aortae and vena cavae was detected by RT-PCR. Western analysis detected TG1 and TG4, but not FXIII, in rat aortae and vena cavae and in TG2 knockout and wild-type mouse aortae. Immunostaining confirmed the presence of TG1, TG2, and TG4 in rat aortae and vena cavae, notably in smooth muscle cells; FXIII was absent. K5 and T26, FITC-labeled peptide substrates specific for active TG1 and TG2, respectively, were incorporated into rat aortae and vena cavae and wild-type, but not TG2 knockout, mouse aortae. These studies demonstrate that TG2-independent TG activity exists in the vasculature and that TG1 and TG4 are expressed in vascular tissues.
Department of Pharmacology and Toxicology, Michigan State University, East Lansing, 48824, USA. john2949@msu.edu
Kyle B
KB
Johnson
Humphrey
H
Petersen-Jones
Janice M
JM
Thompson
Kiyotaka
K
Hitomi
Miho
M
Itoh
Erik N T P
EN
Bakker
Gail V W
GV
Johnson
Gozde
G
Colak
Stephanie W
SW
Watts
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000201:enzymology*; D015153:Blotting, Western; D002103:Cadaverine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors; D003432:Cross-Linking Reagents; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005176:Factor XIII / Q000096:biosynthesis; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D032389:Myocytes, Smooth Muscle / Q000201:enzymology*; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D011503:Transglutaminases / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D014683:Vena Cava, Superior / Q000166:cytology / Q000201:enzymology
D003432:Cross-Linking Reagents; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; C000717609:Tgm2 protein, rat; D005176:Factor XIII; C418702:transglutaminase 4; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; C105804:transglutaminase 1; D019204:GTP-Binding Proteins; D016650:Fluorescein-5-isothiocyanate; C008542:monodansylcadaverine; D002103:Cadaverine