RIPK1 regulates cell function and death mediated by UVB radiation and TNF-α

Area of Science:

• Cell Biology
• Molecular Biology
• Dermatology

Background:

• The RIPK1 protein is crucial in inflammatory responses, oxidative stress, and cell death pathways.
• Epidermal cells form the skin's protective barrier, susceptible to radiation-induced damage.
• RIPK1 acts upstream of the NF-κB pathway, influencing inflammation and cell death.

Purpose of the Study:

• To investigate the role of RIPK1 in HaCaT epidermal cells.
• To analyze the effects of RIPK1 gene knockout on cell function and death.
• To examine RIPK1's regulation of UVB or TNF-α-induced cellular responses.

Main Methods:

• Utilized CRISPR/Cas9 gene editing to create a stable RIPK1 knockout HaCaT cell line (HaCaT^RIP1KO).
• Compared HaCaT^RIP1KO with wild-type (HaCaT^WT) cells under resting conditions and after exposure to UVB or TNF-α.
• Assessed cell morphology, proliferation, cell cycle, apoptosis, and inflammatory factor expression (IL-1α).

Main Results:

• RIPK1 knockout did not alter resting cell morphology but slowed proliferation and arrested the cell cycle at G2M phase.
• HaCaT^RIP1KO cells exhibited increased sensitivity to TNF-α-induced cell death and apoptosis, potentially via NF-κB pathway inhibition.
• UVB exposure caused more significant growth inhibition and IL-1α upregulation in HaCaT^RIP1KO cells, involving P38 MAPK and NF-κB pathways.

Conclusions:

• RIPK1 plays a significant role in regulating pro-survival signals within epidermal cells.
• RIPK1 knockout sensitizes HaCaT cells to death and inflammatory stimuli, highlighting its protective function.
• The study elucidates RIPK1's involvement in epidermal cell responses to stress and damage.