Tissue-specific endothelial cell heterogeneity contributes to unequal inflammatory responses

Area of Science:

• Immunology
• Vascular Biology
• Transplantation Science

Background:

• Endothelial cells (EC) are crucial for maintaining vascular homeostasis and regulating inflammation.
• In organ transplantation, EC serve as direct targets of the alloimmune response.
• Variations in EC characteristics across different organs may contribute to organ-specific differences in transplant rejection risk.

Purpose of the Study:

• To investigate the heterogeneity of vascular endothelial inflammatory responses across different organ beds.
• To determine if tissue-specific EC differences contribute to varying alloimmune risks in organ transplantation.

Main Methods:

• Analysis of gene expression in human cardiac allograft biopsies.
• In vitro characterization of inducible inflammatory phenotypes in EC from heart, lung, kidney, and liver.
• Assessment of adhesion molecule expression, chemokine profiles, and immune cell recruitment.
• Validation using public datasets of organ-specific endothelial transcriptomes.

Main Results:

• Endothelial inflammatory response genes were upregulated in rejecting cardiac allografts.
• Cardiac EC demonstrated higher upregulation of VCAM-1 and greater leukocyte adhesion compared to hepatic EC after stimulation.
• Distinct chemokine profiles were observed in EC from different organs.
• Differential baseline expression of immune-regulating genes was confirmed across organ-specific EC transcriptomes.

Conclusions:

• Heterogeneity in endothelial cell inflammatory responses exists across different organs.
• Differential baseline expression of immune-regulating genes in EC may underlie organ-specific variations in vascular inflammatory responses and transplant outcomes.