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Updated: Mar 20, 2026
Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage
Published on: February 15, 2020
Effect of UVC radiation on mouse fibroblasts deficient for FAS-associated protein with death domain
Lidija Begović1, Maja Antunovic2, Igor Matic2
1a Department of Biology , University of J. J. Strossmayer in Osijek , Osijek , Croatia ;
Purpose:
Ultraviolet (UV) radiation-induced apoptosis enabled us to study the mechanism of DNA damage and to investigate how cells avoid consequences of damaged DNA. Cells with extensive DNA damage activate extrinsic and intrinsic pathways of apoptosis. The extrinsic pathway is coupled to a FAS-associated protein with death domain (FADD), an adaptor protein molecule necessary for mediating apoptotic signals through the cell.
Materials And Methods:
Viability and apoptosis of wild-type and FADD-deficient mouse embryonic fibroblasts were investigated 1, 3, 24 and 48 h after exposure to three doses (50, 75 and 300 J/m(2)) of UVC radiation. Morphological changes were observed using DNA binding dyes (Hoechst and propidium iodide) while biochemical changes were monitored using immunodetection of the poly (ADP-ribose) polymerase (PARP) protein cleavage and caspase-3 activity assay.
Results:
Results showed that the difference in cell death response between wild-type and FADD-deficient cells depended on dose and incubation time after exposure to UVC radiation. FADD-deficient cells are more sensitive to UVC radiation. Even though FADD-deficient cells lack an adapter protein of apoptotic extrinsic pathway, higher doses of UVC triggered their apoptotic response, while wild-type cells die mainly due to necrosis. A different pattern of caspase 3 activity and PARP cleavage was observed 24 h after radiation between two cell lines confirming higher apoptotic response in FADD-deficient cells.
Conclusions:
Wild-type cells can execute apoptosis via both, the mitochondrial and the receptor-mediated pathway whereas FADD-deficient cells can only activate the intrinsic pathway. There is a difference in UVC radiation response between two cell lines indicating the role of FADD in the selection of cell death modality.
Insights
Ultraviolet (UV) radiation triggers apoptosis, a programmed cell death. FAS-associated protein with death domain (FADD) influences cell death pathways, with FADD-deficient cells showing increased sensitivity to UVC radiation.
Area of Science:
- Cellular Biology
- Molecular Biology
- Radiation Biology
Background:
- Ultraviolet (UV) radiation induces DNA damage, activating cellular apoptosis pathways.
- Apoptosis, or programmed cell death, can be initiated through extrinsic and intrinsic pathways.
- The extrinsic pathway involves the FAS-associated protein with death domain (FADD), crucial for transmitting apoptotic signals.
Purpose of the Study:
- To investigate the role of FADD in cellular response to UVC radiation-induced DNA damage.
- To compare apoptosis and cell viability between wild-type and FADD-deficient cells post-UVC exposure.
- To elucidate how FADD influences the choice between different cell death modalities.
Main Methods:
- Exposure of wild-type and FADD-deficient mouse embryonic fibroblasts to varying doses of UVC radiation.
- Assessment of cell viability and apoptosis at different time points (1, 3, 24, 48 hours).
- Morphological analysis using DNA binding dyes and biochemical assays including PARP cleavage and caspase-3 activity.
Main Results:
- FADD-deficient cells exhibited higher sensitivity to UVC radiation compared to wild-type cells.
- UVC radiation triggered apoptosis in FADD-deficient cells, while wild-type cells predominantly underwent necrosis at higher doses.
- Distinct patterns of caspase-3 activity and PARP cleavage were observed, confirming a greater apoptotic response in FADD-deficient cells.
Conclusions:
- FADD plays a significant role in determining the cell death pathway activated by UVC radiation.
- FADD-deficient cells, lacking the extrinsic pathway, rely solely on the intrinsic pathway for apoptosis.
- The study highlights FADD's importance in regulating the cellular response to DNA damage and selecting cell death mechanisms.
