Functional interactions between Mi-2β and AP1 complexes control response and recovery from skin barrier disruption

Area of Science:

• Cell Biology
• Epigenetics
• Dermatology

Background:

• Keratinocytes are crucial for skin integrity, responding to environmental signals via gene induction.
• Epigenetic mechanisms, including chromatin remodeling, play a role in regulating these responses.
• The nucleosome remodeler Mi-2β's function in keratinocyte stress response is not fully understood.

Purpose of the Study:

• To investigate the role of epigenetic changes in keratinocyte transcriptional response to stress.
• To elucidate the specific function of the nucleosome remodeler Mi-2β in skin barrier homeostasis.
• To understand the interplay between Mi-2β and AP1 transcription factors during stress signaling.

Main Methods:

• Comparative analysis of chromatin accessibility and gene expression in mouse and human keratinocytes.
• Assessment of transcriptional and epigenetic changes following barrier disruption.
• Investigation of Mi-2β depletion effects on gene regulation and skin barrier function.
• Chromatin immunoprecipitation to identify protein-DNA interactions.

Main Results:

• Transcriptional responses to barrier disruption and Mi-2β loss show significant overlap.
• Mi-2β represses genes involved in barrier disruption response by restricting AP1-binding sites.
• Mi-2β depletion leads to altered AP1 complex dynamics (JUNB vs. c-JUN) at regulatory sites.
• Loss of Mi-2β does not impede barrier repair but is essential for restoring homeostasis.

Conclusions:

• Short-lived epigenetic modifications support keratinocyte stress response.
• Mi-2β acts as a key repressor of stress-induced genes, facilitating rapid response and resolution.
• A dynamic competition between Mi-2β and AP1 complexes regulates transcriptional plasticity for skin homeostasis.