MKs express and synthesize FXIII-A. (A) RT-PCR analysis of different TGs by human MKs. The amplification products were resolved on agarose gel and visualized by ethidium bromide staining. Actin amplification was used as a control. (B) Western blot analysis of FXIII-A in human MKs. FXIII from human plasma was used as a positive control. (C) Analysis of intracellular TG activity of FXIII in human MKs. MK lysates were incubated with biotinylated cadaverine in the absence or presence of EDTA or Ca2+, resolved by SDS-PAGE, and blotted with peroxidase-conjugated avidin. TG activity was completely reverted upon calcium sequestering with EDTA. (D) Extracellular TG activity was demonstrated by ELISA assay of cadaverine incorporation into pFN upon adhesion of MKs for 16 hours and DOC treatment. TG activity was significantly reduced by incubation with TG inhibitors such as IAA or CYS (10μM each). *P < .05.
