HIF-2α is essential for carotid body development and function.

Area of Science:

• Physiology
• Cellular Biology
• Molecular Biology

Background:

• Mammalian adaptation to oxygen flux involves cellular and physiological mechanisms, including the sympathetic nervous system and carotid body (CB).
• Hypoxia Inducible Factors (HIFs) orchestrate transcriptional responses to hypoxia, interacting synergistically with other adaptive mechanisms.

Purpose of the Study:

• To investigate the developmental requirement and function of HIF-2α in the carotid body.
• To elucidate the role of HIF-2α in glomus cell survival and the subsequent physiological consequences of its absence.

Main Methods:

• Utilized a mouse model to study the developmental necessity of HIF-2α in carotid body glomus cells.
• Assessed ventilatory responses, arterial pressure regulation, exercise performance, and glucose homeostasis in the absence of HIF-2α.
• Examined the correlation between glomus cell expansion and mTORC1 activation, and the effect of rapamycin treatment.

Main Results:

• Demonstrated an absolute developmental requirement for HIF-2α for the growth and survival of oxygen-sensitive carotid body glomus cells.
• Mice lacking HIF-2α in CB glomus cells exhibited impaired ventilatory responses to hypoxia.
• Observed significant effects on arterial pressure regulation, exercise performance, and glucose homeostasis due to the loss of CB function.
• Found that glomus cell expansion is correlated with mTORC1 activation and can be inhibited by rapamycin.

Conclusions:

• HIF-2α plays a critical and indispensable role in the development, growth, and function of the carotid body.
• The carotid body, regulated by HIF-2α, is crucial for mediating physiological adaptations to hypoxia.
• Targeting HIF-2α or related pathways like mTORC1 may offer therapeutic avenues for conditions related to hypoxia response.