Notch1 deficiency results in decreased inflammation during wound healing and regulates vascular endothelial growth factor receptor-1 and inflammatory cytokine expression in macrophages.
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.
Outtz
Hasina Hamilton
HH
Department of Pathology, Columbia University Medical Center, New York, NY 10032, USA.
Wu
June K
JK
Wang
Xing
X
Kitajewski
Jan
J
D000818:Animals; D002469:Cell Separation; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D005434:Flow Cytometry; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000276:immunology*; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D018919:Neovascularization, Physiologic; D051881:Receptor, Notch1 / Q000172:deficiency / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis / Q000276:immunology*; D014945:Wound Healing / Q000276:immunology*
D016207:Cytokines; C497762:Notch1 protein, mouse; D051881:Receptor, Notch1; D040281:Vascular Endothelial Growth Factor Receptor-1