Notch1 deficiency results in decreased inflammation during wound healing and regulates vascular endothelial growth factor receptor-1 and inflammatory cytokine expression in macrophages.

Abstract

We investigated whether Notch signaling plays a role in regulating macrophage responses to inflammation. In a wound healing assay, macrophage recruitment was decreased in Notch1(+/-) mice, and the wounds were characterized by decreased TNF-α expression. As wound healing progressed, Notch1(+/-) wounds had increased vascularization and collagen deposition compared with wild-type wounds. In mice with myeloid-specific Notch1 deletion, wounds had decreased macrophage recruitment as well as decreased TNF-α expression, indicating the specific role of Notch1 in the inflammatory response in these cells. In vitro, we found that vascular endothelial growth factor receptor-1 (VEGFR-1) was upregulated in macrophages in response to LPS/IFN-γ and that this upregulation depended on Notch signaling. Furthermore, macrophages from Notch1(+/-) mice had decreased expression of VEGFR-1 compared with macrophages from wild-type mice, whereas VEGFR-1 expression in Notch4(-/-) macrophages was normal. Inhibition of Notch signaling decreased induction of the inflammatory cytokines IL-6, IL-12, CXCL10, MCP-1, monokine induced by IFN-γ, and TNF-α in macrophages in response to LPS/IFN-γ. Additionally, macrophages from Notch1(+/-) mice demonstrated decreased induction of IL-6, IL-12, and TNF-α in response to stimulation compared with wild-type mice. Thus, both pharmacological inhibition of Notch and genetic analysis demonstrate that Notch1 regulates VEGFR-1 and cytokine expression in macrophages. We have also established that Notch1 is important for the inflammatory response during wound healing in mice.

• Authors: Hasina Hamilton Outtz, June K Wu, Xing Wang, Jan Kitajewski
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 185 Issue 7 Pg. 4363-73 (Oct 01 2010) ISSN: 1550-6606 [Electronic] United States
• PMID: 20739676 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Cytokines
• Notch1 protein, mouse
• Receptor, Notch1
• Vascular Endothelial Growth Factor Receptor-1

Topics

• Animals
• Cell Separation
• Chemotaxis, Leukocyte (immunology)
• Cytokines (biosynthesis, immunology)
• Flow Cytometry
• Gene Expression
• Gene Expression Regulation (immunology)
• Immunohistochemistry
• Inflammation (immunology, metabolism)
• Macrophages (immunology, metabolism)
• Mice
• Mice, Mutant Strains
• Neovascularization, Physiologic
• Receptor, Notch1 (deficiency, immunology)
• Reverse Transcriptase Polymerase Chain Reaction
• Signal Transduction (immunology)
• Vascular Endothelial Growth Factor Receptor-1 (biosynthesis, immunology)
• Wound Healing (immunology)