Sepsis Patients Display a Reduced Capacity to Activate Nuclear Factor-κB in Multiple Cell Types

Area of Science:

• Immunology
• Cellular Biology
• Critical Care Medicine

Background:

• Sepsis is a life-threatening condition characterized by organ dysfunction.
• A key feature of sepsis is immunosuppression, leading to impaired leukocyte function.
• The precise cellular signaling mechanisms driving sepsis-induced immunosuppression remain incompletely understood.

Purpose of the Study:

• To investigate cell-specific signaling events responsible for the immunosuppressed phenotype observed in sepsis.
• To identify defects in key signaling pathways within immune cells of sepsis patients.

Main Methods:

• Ex vivo study involving 19 sepsis patients and 19 healthy controls.
• Analysis of phosphorylation states of p38 mitogen-activated protein kinase and nuclear factor kappa-light-chain-enhancer of activated B cells in stimulated CD4 T cells, CD8 T cells, B cells, monocytes, and neutrophils.
• Measurement of messenger RNA expression levels of key signaling molecules and regulators in neutrophils and peripheral blood mononuclear cells.

Main Results:

• Monocytes from sepsis patients showed reduced nuclear factor kappa-light-chain-enhancer of activated B cells phosphorylation upon stimulation.
• Phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells was also diminished in stimulated B cells, CD4 T cells, and CD8 T cells from sepsis patients.
• Differential expression of messenger RNA for nuclear factor kappa-light-chain-enhancer of activated B cells, A20, p38 mitogen-activated protein kinase, and mitogen-activated protein kinase phosphatase-1 was observed in sepsis patients.

Conclusions:

• Sepsis-induced immunosuppression is associated with a defect in the capacity to phosphorylate nuclear factor kappa-light-chain-enhancer of activated B cells.
• This signaling defect occurs in both lymphoid cells and monocytes.
• Understanding these cell-specific signaling alterations is crucial for addressing sepsis-related immune dysfunction.