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MCPIP1 contributes to the inflammatory response of UVB-treated keratinocytes
Beata Bugara1, Piotr Konieczny1, Agnieszka Wolnicka-Glubisz2
1Department of General Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
Background:
Monocyte chemoattractant protein-1-induced protein-1 (MCPIP1), also known as regnase-1, negatively regulates many cellular processes including the cellular response to inflammatory agents, differentiation, viability, and proliferation. It possesses a PilT N-terminus (PIN) domain that is directly involved in regulating the stability of transcripts and miRNAs by recognizing stem loop structures and degrading them by endonucleolytic cleavage.
Objective:
We investigated the role of MCPIP1 in the response of human primary keratinocytes to UVB stress.
Methods:
Keratinocytes were treated with UVB, siRNA against MCPIP1, pharmacological inhibitors of signaling pathways, or subjected to control treatments. The mRNA and protein levels of MCPIP1 and MCPIP1-dependent changes gene expression were analyzed by quantitative (Q)-RT-PCRs and Western blots. Secretion of TNFα and IL-8 was determined by ELISA.
Results:
UVB treatment of keratinocytes induced upregulation of MCPIP1 at the mRNA level after 4-8h and at the protein level after 8-16h. MCPIP1 abundance depended on NF-κB activity. Using an siRNA strategy, we found that diminished MCPIP1 resulted in an up-regulation of transcripts coding for IL-8, TNFα, COX-2, and BCL-2, as well as an enhanced release of IL-8. Moreover, decreased phosphorylation of NF-κB and p38 signaling pathways were observed in addition to a slight up-regulation of ERK1/2 directly after UVB treatment. Twenty-four hours later, decreased phosphorylation was observed only for NF-κB and p38. Furthermore, in MCPIP1-suppressed cells, the levels of pro-apoptotic Puma, the phosphorylated form of p53 and the abundance of its target p21 as well as the activity of caspase 3 decreased, while the level of cyclin D1 increased.
Conclusion:
MCPIP1 contributes to the UVB response of keratinocytes by altering metabolic and apoptotic processes and the release of inflammatory mediators.
Insights
Monocyte chemoattractant protein-1-induced protein-1 (MCPIP1) regulates cellular responses to UVB stress in human keratinocytes. Suppressing MCPIP1 alters inflammatory mediator release and affects metabolic and apoptotic pathways.
Area of Science:
- Dermatology
- Molecular Biology
- Cell Biology
Background:
- Monocyte chemoattractant protein-1-induced protein-1 (MCPIP1), also known as regnase-1, is a key negative regulator of cellular processes.
- MCPIP1 contains a PIN domain crucial for degrading transcripts and miRNAs by recognizing stem-loop structures.
Purpose of the Study:
- To investigate the role of MCPIP1 in human primary keratinocytes' response to ultraviolet B (UVB) radiation.
- To elucidate the molecular mechanisms underlying MCPIP1's function in UVB-stressed keratinocytes.
Main Methods:
- Human primary keratinocytes were exposed to UVB irradiation and treated with MCPIP1 siRNA or pharmacological inhibitors.
- Quantitative RT-PCR and Western blotting were used to analyze MCPIP1 levels and gene expression.
- ELISA was employed to measure the secretion of inflammatory cytokines like TNFα and IL-8.
Main Results:
- UVB induced MCPIP1 upregulation at both mRNA and protein levels in keratinocytes, dependent on NF-κB activity.
- MCPIP1 suppression led to increased IL-8, TNFα, COX-2, and BCL-2 transcripts and enhanced IL-8 release.
- MCPIP1 depletion affected NF-κB, p38, and ERK1/2 signaling pathways, and modulated apoptosis-related proteins (Puma, p53, p21) and cell cycle regulator cyclin D1.
Conclusions:
- MCPIP1 plays a significant role in the keratinocyte response to UVB stress.
- MCPIP1 influences UVB-induced alterations in metabolic and apoptotic processes and the secretion of inflammatory mediators.