Human endothelial cell cultures: phenotypic modulation by leukocyte interleukins

Area of Science:

• Cell Biology
• Immunology
• Vascular Biology

Background:

• Endothelial cells form the inner lining of blood vessels.
• Activated mononuclear leukocytes release soluble factors that can influence other cell types.
• The morphology of endothelial cells is crucial for vascular function and integrity.

Purpose of the Study:

• To investigate the effects of soluble factors from activated mononuclear leukocytes on endothelial cell morphology.
• To identify specific cytokines responsible for inducing shape changes in endothelial cells.
• To explore the cytoskeletal rearrangements associated with these morphological alterations.

Main Methods:

• Culturing human umbilical vein endothelial cells.
• Exposure of endothelial cells to culture media conditioned by lectin-activated mononuclear leukocytes.
• Treatment with purified interleukins (Interleukin 1, Interleukin 2) and gamma-interferon.
• Microscopic observation of cell morphology and cytoskeletal organization (actin, intermediate filaments, microtubules).
• Assessment of reversibility and specificity of the observed effects.

Main Results:

• Activated mononuclear leukocyte supernatants induced significant elongation and dendritic morphology in endothelial cells.
• These shape changes were specific to endothelial cells and reversible.
• Cytoskeletal reorganization included parallel actin arrays and penetration of filaments into cytoplasmic processes.
• Interleukin 1 combined with gamma-interferon mimicked the effects of the leukocyte supernatants.
• Interleukin 2 and gamma-interferon alone had minimal effects.

Conclusions:

• Soluble factors from activated mononuclear leukocytes, particularly Interleukin 1 and gamma-interferon, profoundly alter endothelial cell shape.
• These cytokines induce significant cytoskeletal remodeling in endothelial cells.
• The observed endothelial cell changes may be relevant to the angiogenic activity of mononuclear cell products.