Mouse dendritic cells in the steady state: Hypoxia, autophagy, and stem cell factor

Area of Science:

• Immunology
• Cell Biology
• Physiology

Background:

• Dendritic cells (DCs) are crucial innate immune cells bridging innate and adaptive immunity.
• Tissue microenvironments, including oxygen tension, influence DC heterogeneity and function.
• The impact of tissue hypoxia on DC physiology remains poorly understood.

Purpose of the Study:

• To investigate the hypoxic state of dendritic cells (DCs) in the mouse bone marrow (BM) and spleen.
• To explore the role of stem cell factor (SCF) in modulating DC hypoxia and related pathways.
• To understand the interplay between hypoxia, SCF, and autophagy in DC homeostasis.

Main Methods:

• Flow cytometry using hypoxia markers like HIF-1α and pimonidazole (PIM) to assess DC hypoxia in vivo.
• Analysis of DC subsets, specifically c-kit+ and c-kit- DCs, for differential hypoxic phenotypes.
• Gene expression microarrays and gene set enrichment analysis of SCF-stimulated DCs under hypoxic conditions.

Main Results:

• Mouse DCs in the spleen and BM demonstrate a hypoxic phenotype.
• c-kit+ DCs exhibit a more pronounced hypoxic phenotype compared to c-kit- DCs.
• SCF signaling in hypoxic DCs inhibits autophagy-related gene sets, impacting cellular pathways.

Conclusions:

• Hypoxic response and autophagy are integral to DC homeostasis under steady-state conditions.
• SCF plays a significant role in modulating DC hypoxia and autophagy.
• These findings provide insights into the regulation of DC function by microenvironmental factors like oxygen tension.