Hypoxia enhances ILC3 responses through HIF-1α-dependent mechanism

Area of Science:

• Immunology
• Cell Biology
• Gastroenterology

Background:

• Group 3 innate lymphoid cells (ILC3) are vital for intestinal mucosal homeostasis.
• Hypoxia-inducible factor (HIF) regulates immune cell responses to low oxygen.
• The specific role of HIF in intestinal ILC3 function remains largely unexplored.

Purpose of the Study:

• To investigate the impact of hypoxia on intestinal ILC3.
• To elucidate the involvement of HIF-1 signaling in hypoxia-mediated ILC3 modulation.
• To understand the functional consequences of HIF-1α in ILC3 during homeostasis and infection.

Main Methods:

• Assessment of intestinal ILC3 proliferation and activation under hypoxic conditions.
• Pharmacological manipulation of HIF-1α activity (stabilization and blockade).
• Analysis of gene expression changes and cytokine production (IL-17, IL-22) in ILC3.
• In vivo studies using HIF-1α deficient models and infection models (Clostridioides difficile).

Main Results:

• Hypoxia significantly increased intestinal ILC3 proliferation and activation.
• These effects were mimicked by HIF-1α stabilization and reversed by HIF-1 blockade.
• Increased ILC3 activation was dependent on a HIF-1α transcriptional program, independent of mTOR or glycolysis.
• HIF-1α deficiency in ILC3 impaired IL-17 and IL-22 production, leading to reduced target gene expression in the epithelium and increased susceptibility to C. difficile infection.

Conclusions:

• HIF-1α activation in intestinal ILC3 enhances their function under steady-state conditions.
• HIF-1α signaling in ILC3 is critical for effective host defense against intestinal pathogens.
• Targeting HIF-1α in ILC3 may represent a therapeutic strategy for intestinal inflammatory diseases and infections.