HILPS, a long noncoding RNA essential for global oxygen sensing in humans.

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Cellular adaptation to low oxygen (hypoxia) is crucial for metazoan survival.
• Mechanisms of oxygen sensing vary across species and remain incompletely understood.
• Hypoxia-inducible factor 1α (HIF1α) is a key regulator of the cellular response to hypoxia.

Purpose of the Study:

• To functionally characterize a novel long noncoding RNA (lncRNA) involved in hypoxia adaptation.
• To elucidate the role of this lncRNA in the HIF1α regulatory pathway.
• To identify new components of the oxygen-sensing machinery.

Main Methods:

• Identification and naming of a novel lncRNA, HILPS (hypoxia-induced lncRNA for PLK1 stabilization).
• Analysis of HILPS expression in normal and cancer cells under normoxia and hypoxia.
• Investigation of the interaction between HILPS, polo-like kinase 1 (PLK1), and HIF1α.
• Assessment of cellular adaptation defects upon HILPS depletion during hypoxia.

Main Results:

• HILPS is robustly induced by HIF1α and binds to PLK1, preventing its proteasomal degradation.
• Stabilized PLK1 phosphorylates HIF1α, enhancing its stability and creating a positive feed-forward loop.
• Depletion of HILPS leads to catastrophic defects in hypoxia adaptation in both normal and cancer cells.
• The HILPS-PLK1-HIF1α pathway forms a critical oxygen-sensing axis.

Conclusions:

• A novel regulatory pathway involving HILPS, PLK1, and HIF1α is identified as a key mechanism for oxygen sensing.
• This pathway is essential for cellular adaptation to hypoxia in human cells, including cancer cells.
• The HILPS-PLK1-HIF1α axis represents a significant discovery in understanding human physiological and pathogenic responses to oxygen deprivation.