The TGF尾1 pathway is required for NF魏B dependent gene expression in mouse keratinocytes

详细信息    查看全文

• 作者：Kelly A. Hogan ; An ; Ravindran ; Michael A. Podolsky ; Adam B. Glick
• 关键词：EMSA ; electrophoretic mobility shift assay ; TGF尾1 ; transforming growth factor-beta 1 ; TNF伪 ; tumor necrosis factor alpha ; NFkappaB ; nuclear factor kappaB ; IK尾 ; I kappa尾 ; IK尾sr ; I kappa尾 super repressor ; TAK1 ; TGF尾1 activated kinase 1 ; IKK伪 ; I kappa Kinase伪 ; JNK ; cJun N-terminal kinases ; SBE ; Smad binding elements ; ALK5 ; activin receptor-like kinase 5
• 刊名：Cytokine
• 出版年：December, 2013
• 年：2013
• 卷：64
• 期：3
• 页码：652-659
• 全文大小：880 K

文摘

The transforming growth factor-beta 1 (TGF尾1) and NF魏B pathways are important regulators of epidermal homeostasis, inflammatory responses and carcinogenesis. Previous studies have shown extensive crosstalk between these pathways that is cell type and context dependent, but this has not been well-characterized in epidermal keratinocytes. Here we show that in primary mouse keratinocytes, TGF尾1 induces NF魏B-luciferase reporter activity that is dependent on both NF魏B and Smad3. TGF尾1-induced NF魏B-luciferase activity was blocked by the I魏B inhibitor parthenolide, the I魏B super-repressor, a dominant negative TGF尾1-activated kinase 1 (TAK1) and genetic deletion of NF魏B1. Coexpression of NF魏B p50 or p65 subunits enhanced NF魏B-luciferase activity. Similarly, inhibition of the TGF尾1 type I receptor with SB431542 or genetic deletion of Smad3 blocked TGF尾1 induction of NF魏B-luciferase. TGF尾1 rapidly induced IKK phosphorylation but did not cause a detectable decrease in cytoplasmic I魏B levels or nuclear translocation of NF魏B subunits, although EMSA showed rapid NF魏B nuclear binding activity that could be blocked by SB431542 treatment. TNF伪, a well characterized NF魏B target gene was also induced by TGF尾1 and this was blocked in NF魏B+/鈭?and 鈭?鈭?keratinocytes and by the I魏B super-repressor. To test the effects of the TGF尾1 pathway on a biologically relevant activator of NF魏B, we exposed mice and primary keratinocytes in culture to UVB irradiation. In primary keratinocytes UVB caused a detectable increase in levels of Smad2 phosphorylation that was dependent on ALK5, but no significant increase in SBE-dependent gene expression. Inhibition of TGF尾1 signaling in primary keratinocytes with SB431542 or genetic deletion of Tgfb1 or Smad3 suppressed UVB induction of TNF伪 message. Similarly, UVB induction of TNF伪 mRNA was blocked in skin of Tgfb1+/鈭?mice. These studies demonstrate that intact TGF尾1 signaling is required for NF魏B-dependent gene expression in mouse keratinocytes and skin and suggest that a convergence of these pathways in the nucleus rather than the cytoplasm may be critical for regulation of inflammatory pathways in skin by TGF尾1.