FGF8 signaling is chemotactic for cardiac neural crest cells

Abstract

SUMMARY Cardiac neural crest cells migrate into the pharyngeal arches where they support development of the pharyngeal arch arteries. The pharyngeal endoderm and ectoderm both express high levels of FGF8. We hypothesized that FGF8 is chemotactic for cardiac crest cells. To begin testing this hypothesis, cardiac crest was explanted for migration assays under various conditions. Cardiac neural crest cells migrated more in response to FGF8. Single cell tracing indicated that this was not due to proliferation and subsequent transwell assays showed that the cells migrate toward an FGF8 source. The migratory response was mediated by FGF receptors (FGFR) 1 and 3 and MAPK/ERK intracellular signaling. To test whether FGF8 is chemokinetic and/or chemotactic in vivo, dominant negative FGFR1 was electroporated into the premigratory cardiac neural crest. Cells expressing the dominant negative receptor migrated slower than normal cardiac neural crest cells and were prone to remain in the vicinity of the neural tube and die. Treating with the FGFR1 inhibitor, SU5402 or an FGFR3 function-blocking antibody also slowed neural crest migration. FGF8 over-signaling enhanced neural crest migration. Neural crest cells migrated to an FGF8-sosked bead placed dorsal to the pharynx. Finally, an FGF8 producing plasmid was electroporated into an ectopic site in the ventral pharyngeal endoderm. The FGF8 producing cells attracted a thick layer of mesenchymal cells. DiI labeling of the neural crest as well as quail-to-chick neural crest chimeras showed that neural crest cells migrated to and around the ectopic site of FGF8 expression. These results showing that FGF8 is chemotactic and chemokinetic for cardiac neural crest adds another dimension to understanding the relationship of FGF8 and cardiac neural crest in cardiovascular defects.

Fibulin-1 Binds to Fibroblast Growth Factor 8 with High Affinity

“…In this report, we have investigated whether FBLN1, a known extracellular glycoprotein (7) as well as an intracellular integrin ␤1-binding protein (22), and FGF8, a known effector of NCC migration (21), associate with each other biochemically and have synergistic effects on embryonic development or survival. Herein, we show for the first time that FBLN1 binds with high affinity to FGF8 and protects it from enzymatic degradation by ADAM17.…”

“…Studies show that inhibition of FGF8 signaling in the absence of NCC ablation causes under-proliferation of secondary heart field cells, resulting in a shortened outflow tract (18). Additionally, it has been shown that FGF8 acts as a chemotactic and chemokinetic signal for cardiac neural crest cells both in vitro and in vivo (21). Thus, precise levels of FGF8 signaling seem critical for normal outflow tract development and morphogenesis.…”

The neural crest

“…In the mouse, FGF2 and FGF8 have been found to control NC migration towards the branchial arches (Kubota and Ito, 2000;Trokovic et al, 2005), while in chick an equivalent role has been described for VEGFA . Also in chick, cardiac NC cells seem to rely on FGF8 and semaphorin 3C (here acting as a positive cue) to reach the heart (Lepore et al, 2006;Sato et al, 2011). Finally, data from chick and mouse have demonstrated that GDNF controls enteric NC rostrocaudal progression along the gut to form the enteric nervous system (Sasselli et al, 2012;Young et al, 2001).…”

Chemokine and Fgf signalling act as opposing guidance cues in formation of the lateral line primordium

“…Because in other tissues Fgfs act as chemoattractive signals (Sutherland et al, 1996;Sato et al, 2011;Kadam et al, 2012), we considered the possibility that Fgfs also have a more direct role in lateral line cell migration. We analysed the expression of Fgf signalling components and found that after the fusion between the SPCs and primordium, fgf3 and fgf10 are expressed in the leading zone, and fgfr1 in the trailing zone, as previously reported ( , 2008).…”