Priming of neutrophils and differentiated PLB-985 cells by pathophysiological concentrations of TNF-α is partially...

Area of Science:

• Immunology
• Cell Biology

Background:

• Polymorphonuclear leukocytes (PMN) can enter a 'primed' state, exhibiting heightened responsiveness.
• Tumor necrosis factor-alpha (TNF-α) is a key inflammatory cytokine.
• Understanding PMN priming mechanisms is crucial for inflammatory disease research.

Purpose of the Study:

• To investigate the priming effects of TNF-α on human PMN and a differentiated myeloid cell line (PLB-D).
• To elucidate the role of reactive oxygen species (ROS) and specific signaling pathways in TNF-α-induced PMN priming.
• To evaluate the functional consequences of TNF-α priming on cell behavior, including chemotaxis.

Main Methods:

• Human PMN and differentiated PLB-985 cells (PLB-D) were treated with TNF-α.
• Reactive oxygen species (ROS) generation and NADPH oxidase activity were measured.
• Cell surface protein expression (CD11b, gp91(phox)) and MAPK pathway activation (p38, ERK1/2) were assessed.
• Chemotaxis assays were performed to evaluate cell migration.

Main Results:

• TNF-α induced ROS production and primed NADPH oxidase activity in both PMN and PLB-D cells.
• Priming was oxygen-dependent, with reduced ROS generation under anaerobic conditions.
• TNF-α increased cell surface expression of CD11b and gp91(phox) and activated MAPK pathways in PMN.
• Primed PMN and PLB-D cells exhibited enhanced chemotaxis.

Conclusions:

• Pathophysiological concentrations of TNF-α induce PMN priming, characterized by ROS generation, enhanced surface protein expression, MAPK activation, and increased chemotaxis.
• The PLB-D cell line serves as a valuable, genetically modifiable model for studying TNF-α priming mechanisms.
• These findings contribute to understanding inflammatory responses and potential therapeutic targets.