DDB1 prepares brown adipocytes for cold-induced thermogenesis

Area of Science:

• Metabolism and Endocrinology
• Molecular Biology
• Adipose Tissue Biology

Background:

• Brown adipose tissue (BAT) is vital for thermogenesis, particularly during cold stress.
• The precise mechanisms preparing BAT for rapid thermogenic gene activation remain incompletely understood.

Purpose of the Study:

• To elucidate the role of damage-specific DNA binding protein 1 (DDB1) in the rapid transcriptional response of BAT to acute cold exposure.
• To investigate the molecular mechanisms by which DDB1 regulates thermogenic gene expression.

Main Methods:

• Generation and analysis of adipose- or BAT-specific DDB1 knockout mice.
• Assessment of BAT morphology, gene expression (including Ucp1 and Ppargc1a), and response to cold exposure (4 °C).
• Investigation of DDB1's interaction with gene promoters and transcriptional machinery (P-TEFb, Pol II).

Main Results:

• BAT-specific DDB1 deficiency led to whitened BAT, reduced thermogenic gene expression, and hypothermia in cold conditions.
• DDB1 knockout mice exhibited partial lipodystrophy and impaired fatty acid oxidation on a high-fat diet.
• DDB1 was found to bind Ucp1 and Ppargc1a promoters, recruiting P-TEFb to facilitate RNA polymerase II release and gene transcription.

Conclusions:

• DDB1 is a key mediator of rapid thermogenic gene transcription in BAT upon cold challenge.
• DDB1 plays a critical role in preparing BAT for acute cold exposure by regulating key thermogenic genes.
• These findings reveal a novel regulatory mechanism essential for BAT's adaptive response to cold.