Characterization of Tissue Transglutaminase as a Potential Biomarker for Tissue Response toward Biomaterials

Abstract

Tissue transglutaminase (TGase 2) is proposed to be important for biomaterial–tissue interactions due to its presence and versatile functions in the extracellular environment. TGase 2 catalyzes the cross-linking of proteins through its Ca2+-dependent acyltransferase activity. Moreover, it enhances the interactions between fibronectin and integrins, which in turn mediates the adhesion, migration, and motility of the cells. TGase 2 is also a key player in the pathogenesis of fibrosis. In this study, we investigated whether TGase 2 is present at the biomaterial–tissue interface and might serve as an informative biomarker for the visualization of tissue response toward gelatin-based biomaterials. Two differently cross-linked hydrogels were used, which were obtained by the reaction of gelatin with lysine diisocyanate ethyl ester. The overall expression of TGase 2 by endothelial cells, macrophages, and granulocytes was partly influenced by contact to the hydrogels or their degradation products, although no clear correlation was evidenced. In contrast, the secretion of TGase 2 differed remarkably between the different cells, indicating that it might be involved in the cellular reaction toward gelatin-based hydrogels. The hydrogels were implanted subcutaneously in immunocompetent, hairless SKH1-Elite mice. Ex vivo immunohistochemical analysis of tissue sections over 112 days revealed enhanced expression of TGase 2 around the hydrogels, in particular at days 14 and 21 post-implantation. The incorporation of fluorescently labeled cadaverine derivatives for the detection of active TGase 2 was in accordance with the results of the expression analysis. The presence of an irreversible inhibitor of TGase 2 led to attenuated incorporation of the cadaverines, which verified the catalytic action of TGase 2. Our in vitro and ex vivo results verified TGase 2 as a potential biomarker for tissue response toward gelatin-based hydrogels. In vivo, no TGase 2 activity was detectable, which is mainly attributed to the unfavorable physicochemical properties of the cadaverine probe used.

Microbial transglutaminase nanoflowers as an alternative nanomedicine for breast cancer theranostics

“…44,[92][93][94][95] The cellular physiology gets perturbed if the dysregulation of the functionality of transglutaminase occurs. 43,[95][96][97] With the versatility of MTGase facilitating the nanoowers formation by acting as molecular glue, it was demonstrated that they have anticancer properties. The unique rational drug design based on an incentive immobilized enzyme approach led to the uniform shape of petals in these nanoowers, which had the capacity to act as an anti-cancerous drug.…”

Implant Fibrosis and the Underappreciated Role of Myofibroblasts in the Foreign Body Reaction

“…Stress fiber-mediated contraction confers to myofibroblasts the ability to repair tissues by organizing collagen ECM into mechanically resistant scar tissue. It is the excessive production, contraction, and crosslinking of collagen by transglutaminases [ 170 , 171 , 172 ], lysyl hydroxylases [ 173 ], lysyl oxidases [ 174 ], and lysyl oxidase-like enzymes [ 175 ] that result in fibrosis [ 176 , 177 , 178 , 179 ]. In vitro, all fibroblastic cells form stress fibers with stiff plastic or glass culture surfaces in the presence of serum and should thus be considered functional myofibroblasts [ 180 ].…”

The Role of Transglutaminase 2 in the Radioresistance of Melanoma Cells

“…At the same time when cellular material was collected as described for the proliferation assessment, cell culture supernatants were sampled for Western blot analysis. Cell lysates and cell-free supernatants were obtained as described previously [44]. Protein concentrations of cell lysates were determined in order to separate equal protein amounts by SDS-PAGE and immobilize to PVDF membranes by electroblotting as described elsewhere [45].…”