Endothelial cells express the interleukin-1 receptor type I

Area of Science:

• Immunology
• Cell Biology
• Vascular Biology

Background:

• Interleukin-1 (IL-1) significantly impacts vascular cell functions.
• Two main IL-1 receptors exist: IL-1RI (80 Kd) and IL-1RII (68 Kd), found on distinct cell types.
• The presence and role of IL-1 receptors on vascular cells remained largely uncharacterized.

Purpose of the Study:

• To investigate the presence and functionality of Interleukin-1 receptors on vascular endothelial cells.
• To determine the specific type and molecular weight of the IL-1 receptor expressed by endothelial cells.
• To assess the functional response of endothelial cells to IL-1 stimulation.

Main Methods:

• Utilized polyoma-transformed mouse endothelial cell (EC) lines (sEnd.1 and tEnd.1).
• Performed radioiodinated IL-1 alpha binding assays and autoradiography for binding analysis.
• Conducted cross-linking studies and analyzed mRNA expression to identify the IL-1 receptor type.
• Measured IL-6 mRNA expression and bioactivity production in response to IL-1.

Main Results:

• Endothelial cells (sEnd.1 and tEnd.1) exhibited specific and saturable binding sites for IL-1.
• Cross-linking studies and mRNA analysis confirmed the expression of the 80 Kd IL-1 receptor type I (IL-1RI) on EC.
• IL-1 stimulation led to increased IL-6 mRNA expression and bioactivity in EC.
• Human EC and vascular smooth muscle cells also demonstrated mRNA expression for IL-1RI.

Conclusions:

• Vascular endothelial cells express functional Interleukin-1 receptor type I (IL-1RI).
• The IL-1RI on endothelial cells mediates cellular responses, including IL-6 production.
• These findings extend to human endothelial and vascular smooth muscle cells, highlighting the role of IL-1 signaling in the vasculature.