HSG cells, a model in the submandibular clock.

Area of Science:

• Chronobiology
• Molecular Biology
• Cell Biology

Background:

• Circadian rhythms are vital for health, with peripheral tissues displaying unique temporal patterns.
• Human submandibular gland (HSG) cells are established models for studying steroid and growth factor effects.
• Understanding peripheral clocks is crucial for comprehending tissue-specific biological timing.

Purpose of the Study:

• To investigate the transcriptional regulation of the BMAL1 gene in HSG cells.
• To assess the suitability of HSG cells as a model for the submandibular gland clock.
• To explore the role of core clock components in HSG cell circadian rhythmicity.

Main Methods:

• Analysis of BMAL1 gene expression and circadian oscillation in HSG cells following dexamethasone stimulation.
• Identification of ROR and RORE motifs within the BMAL1 regulatory region.
• Assessment of REV-ERBα expression and its involvement in BMAL1 transcription via knockdown experiments.

Main Results:

• BMAL1 gene expression exhibited circadian oscillation in HSG cells upon dexamethasone stimulation.
• The BMAL1 regulatory region contains ROR and RORE motifs within hypomethylated CpG islands and open chromatin.
• REV-ERBα expression also showed circadian oscillation, and its knockdown affected BMAL1 circadian transcription, similar to NIH 3T3 cells.

Conclusions:

• HSG cells demonstrate circadian rhythms in core clock components BMAL1 and REV-ERBα.
• These findings indicate that HSG cells can serve as a valuable model for studying circadian transcriptional regulation in peripheral tissues.
• The study highlights the potential of HSG cells for dissecting the molecular mechanisms of the submandibular gland clock.