Thrombomodulin is synthesized by human mesangial cells

Area of Science:

• Nephrology
• Vascular Biology
• Cell Biology

Background:

• Thrombomodulin (TM) is an endothelial receptor crucial for anticoagulant activity and vascular antithrombogenicity.
• TM presence in the human renal glomerulus was previously attributed solely to endothelial cells.
• The role of TM in mesangial cells (MC) within the glomerulus remained largely unexplored.

Purpose of the Study:

• To investigate the expression and synthesis of thrombomodulin (TM) in human mesangial cells (MC).
• To determine if MC contribute to TM levels within the renal glomerulus.
• To explore the implications of TM synthesis by MC in renal hemostasis and glomerulopathies.

Main Methods:

• Immunocytochemical analysis of TM expression in freshly prepared human glomeruli and cultured MC.
• Quantification of total TM antigen and surface TM activity in MC.
• In situ hybridization to detect TM mRNA transcripts in MC, indicating synthesis.

Main Results:

• Both fresh and cultured human MC demonstrated strong reactivity for TM.
• Quantifiable levels of TM antigen and active TM were detected on and within MC.
• Evidence of TM synthesis by MC, both in vivo and in vitro, was confirmed through transcript detection.

Conclusions:

• Human mesangial cells synthesize functional thrombomodulin (TM).
• The presence and synthesis of TM by both endothelial and mesangial cells underscore its significance in maintaining renal hemostatic balance.
• These findings may help reconcile conflicting reports on TM expression in glomerulopathies and suggest new research directions.