Notch signaling functions downstream of inflammatory signaling to regulate HSPC emergence. (A) qRT-PCR results from the dissected trunk region showed that expression of Notch target genes hey1, hey2, and her15.1 was decreased in tlr4bb and myd88 morphants and increased in ikbaa morphants at 28 hpf. Each bar represents the mean ± SEM of 3 independent samples. *P < .05, **P < .01. (B) hey2 expression was decreased in myd88^−/− embryos. Black arrowheads mark expression of hey2 in the dorsal aorta at 24 hpf. (C) tp1⁺fli1a⁺ cells in Tg(tp1:DsRed/fli1a:EGFP) transgenic embryos were decreased in tlr4bb or myd88 morphants and increased in ikbaa morphants. Left panels, Confocal images of the tp1⁺fli1a⁺ cells in the AGM region at 36 hpf, which were labeled by the white arrowheads. Right panel, Quantification of the tp1⁺fli1a⁺ cells. Each bar represents the mean ± SEM of 3 independent samples. Each sample was composed of at least 6 embryos. *P < .05, **P < .01. (D) Overexpression of NICD in endothelial cells partially rescued the HSPC defect in tlr4bb or myd88 morphants. Top panel, The NICD-GFP⁺ signals. Bottom panels, The expression of runx1 at 36 hpf in the embryos coinjected with tlr4bb or myd88 MOs and fli1a-ep-NICD-GFP construct. Red arrowheads mark GFP signal in the endothelial cells. Black arrowheads mark the expression of runx1 in the AGM region at 36 hpf.