G-CSF modulates LPS-induced apoptosis and IL-8 in human microvascular endothelial cells: involvement of calcium signaling

Area of Science:

• Endothelial Cell Biology
• Immunology
• Hematology

Background:

• Microvascular endothelial cells (mECs) are found in increased numbers in severe sepsis and hemophagocytic syndromes.
• These circulating mECs are viable and can be used to establish cell lines.
• Antigenic profiling of these mECs shows expression of CD36, factor VIIIa, CD95-ligand, CD44, and CD146.

Purpose of the Study:

• To investigate the antioxidative and protective effects of the hematopoietic growth factor G-CSF on microvascular endothelial cells (mECs).
• To determine the impact of G-CSF on lipopolysaccharide (LPS)-induced inflammatory responses and apoptosis in mECs.

Main Methods:

• Microvascular endothelial cells (mECs) were stimulated with LPS (Escherichia coli 0111:B4) for 24 and 48 hours, with and without preincubation with G-CSF.
• Interleukin-8 (IL-8) secretion was measured by ELISA.
• Hemoxygenase-1 (HO-1) expression and caspase 3 activation were assessed by immunohistochemistry and flow cytometry.

Main Results:

• LPS stimulation upregulated IL-8 secretion in mECs by 2-10 fold.
• G-CSF preincubation significantly downregulated LPS-induced IL-8 secretion (20-50%) but did not affect IL-6 production.
• LPS stimulation led to apoptosis and caspase 3 activation in mECs after 48 hours, which was markedly reduced by G-CSF preincubation.

Conclusions:

• G-CSF exhibits a protective effect against LPS-induced inflammatory responses and apoptosis in microvascular endothelial cells.
• G-CSF downregulates IL-8 secretion and caspase 3 activation in mECs stimulated with LPS.
• These findings suggest a potential therapeutic role for G-CSF in conditions involving endothelial cell damage and inflammation, such as SIRS.