Hyperthermia induces reductive stress in murine macrophages

Area of Science:

• Cellular Biology
• Molecular Mechanisms
• Stress Response

Background:

• Hyperthermia-induced heat stress (HS) causes organ injury and mortality.
• The precise molecular mechanisms of HS-induced cell death remain unclear.
• Existing research often focuses on oxidative stress, overlooking other contributing factors.

Purpose of the Study:

• To elucidate the mechanisms of HS-induced cell death in macrophages.
• To investigate the role of oxidative vs. reductive stress in HS-induced PANoptosis.
• To identify potential therapeutic targets for HS-associated diseases.

Main Methods:

• Macrophage cell culture subjected to heat stress.
• Assessment of cell death pathways (pyroptosis, apoptosis, necroptosis) and PANoptosome formation.
• Measurement of reactive oxygen species (ROS) and reductive stress markers (NADPH, thioredoxin system).
• Pharmacological inhibition of caspases and RIPK3.
• In vivo validation in a mouse model of HS-induced intestinal injury.

Main Results:

• HS induced PANoptosis independently of ROS, indicating oxidative stress is not the primary driver.
• HS led to reductive stress, characterized by NADPH accumulation and thioredoxin (Trx) system dysfunction.
• Trx1 aggregation impaired redox regulation, causing mitochondrial damage and DNA damage.
• Dual inhibition of caspases (IDN-6556) and RIPK3 (GSK'872) fully blocked HS-induced PANoptosis.
• The combined inhibition protected against HS-induced intestinal injury in vivo.

Conclusions:

• Reductive stress, mediated by thioredoxin system dysfunction, is the key driver of HS-induced PANoptosis, not oxidative stress.
• Targeting both caspases and RIPK3 offers a novel therapeutic strategy against heat shock-related pathologies.
• Understanding reductive stress mechanisms opens new avenues for treating hyperthermia-induced organ damage.