Mitochondria regulate neutrophil activation by generating ATP for autocrine purinergic signaling

Area of Science:

• Immunology
• Cell Biology
• Mitochondrial Biology

Background:

• Polymorphonuclear neutrophils (PMNs) are critical immune cells.
• ATP release and purinergic signaling via P2Y2 receptors are vital for PMN activation.
• The source of ATP initiating PMN activation was previously unclear.

Purpose of the Study:

• To identify the source of ATP that initiates PMN activation.
• To elucidate the role of mitochondria in early PMN responses.
• To understand the signaling pathways involved in PMN activation.

Main Methods:

• Stimulation of formyl peptide receptors on PMNs.
• Measurement of mitochondrial membrane potential (Δψm).
• Assessment of ATP release and Ca(2+) signaling.
• Inhibition of mitochondrial ATP production.

Main Results:

• Mitochondria provide the ATP that initiates PMN activation.
• Formyl peptide receptor stimulation increases Δψm and triggers rapid mitochondrial ATP release.
• This ATP burst fuels initial purinergic signaling, amplifying Ca(2+) signals and mitochondrial ATP production.
• PMNs subsequently switch to glycolytic ATP production for sustained responses.

Conclusions:

• Mitochondria play a pivotal role in initiating PMN activation through ATP release.
• A two-phase ATP production system (mitochondrial then glycolytic) sustains PMN functions.
• Understanding this mechanism offers insights into immune cell activation and potential therapeutic targets.