Imaging of the ex vivo transglutaminase activity in liver macrophages of sepsis mice.

Imaging of the ex vivo transglutaminase activity in liver macrophages of sepsis mice. Anal Biochem. 2020 Mar 03;:113654 Authors: Su T, Qin XY, Furutani Y, Yu W, Kojima S Abstract Sepsis is the leading cause of death in hospitalized patients and is characterized by a dysregulated inflammatory response to infection and multiple organ failure, including the liver. Transglutaminase 2 (TG2) is--> a multifunctional enzyme that exhibits transamidase, GTPase, and integrin-binding activities and has opposing roles in the regulation of cell growth, differentiation, and apoptosis. TG2 plays both pathogenic and protective roles in liver diseases, revealing the need to examine the ex vivo activities of TG2. Here, we introduce an imaging approach to examine the ex vivo transamidase activity of TG2 based on the combination of intraperitoneal injection of 5-biotinamidopentylamine (5BAPA), a biotinylated substrate for TG2, and fluorescent streptavidin staining in frozen liver sections. Increased 5BAPA signals were observed in the livers of lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-induced sepsis mice. Pharmacological inhibition of TG2 activity ameliorated LPS-induced liver injury. 5BAPA signals were observed in TG2-expressing and F4/80-positive midzonal macrophages, providing direct evidence that activated macrophages are the major cellular source of active TG2 in the livers of sepsis mice. Further studies focusing on the acti...
Source: Analytical Biochemistry - Category: Biochemistry Authors: Tags: Anal Biochem Source Type: research