TPC1 deficiency or blockade augments systemic anaphylaxis and mast cell activity

Area of Science:

• Immunology
• Cell Biology
• Pharmacology

Background:

• Mast cells and basophils drive allergic reactions and anaphylaxis.
• Their activation involves regulated release of inflammatory mediators dependent on calcium (Ca²⁺) signals.
• Two-pore channel (TPC) proteins mediate Ca²⁺ release from intracellular compartments.

Purpose of the Study:

• To investigate the role of TPC1 in regulating calcium homeostasis and exocytosis in mast cells.
• To understand TPC1's mechanism in mast cell degranulation and allergic responses.

Main Methods:

• In vivo studies using TPC1-deficient mice.
• Ex vivo analysis of mast cell degranulation and histamine release.
• Pharmacological inhibition of TPC1.

Main Results:

• TPC1 deficiency in mice resulted in enhanced passive systemic anaphylaxis and hypothermia.
• Ex vivo, TPC1 inhibition augmented mast cell histamine release and degranulation.
• TPC1 appears essential for endolysosomal Ca²⁺ uptake and endoplasmic reticulum Ca²⁺ store filling.

Conclusions:

• TPC1 plays a critical role in regulating mast cell exocytosis and calcium homeostasis.
• Pharmacological targeting of TPC1 offers a potential therapeutic strategy for mast cell-related diseases like allergic hypersensitivity.