During salamander limb regeneration, nerves provide signals that induce the formation of a mass of proliferative cells called the blastema. To better understand these signals, we developed a blastema-dorsal root ganglia (DRG) co-culture model system to test the hypothesis that nerves differentially express genes in response to cues provided by the blastema. DRG with proximal and distal nerve trunks were isolated from axolotls (Ambystoma mexicanum), cultured for five days, and subjected to microarray analysis. Relative to freshly isolated DRG, 1,541 Affymetrix probe sets were identified as differentially expressed and many of the predicted genes are known to function in injury and neurodevelopmental responses observed for mammalian DRG. We then cultured 5-day DRG explants for an additional five days with or without co-cultured blastema cells. On Day 10, we identified 27 genes whose expression in cultured DRG was significantly affected by the presence or absence of blastema cells. Overall, our study established a DRG-blastema in vitro culture system and identified candidate genes for future investigations of axon regrowth, nerve-blastema signaling, and neural regulation of limb regeneration.
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This researchwas funded by the National Science Foundation through its support of the Ambystoma Genetic Stock Center at the University of Kentucky, Lexington, the National Institutes of Health (RC2-NS069480; R-24OD010435) and the Army Research Office (56157-LS-MUR).
Athippozhy, Antony; Lehrberg, Jeffrey; Monaghan, James R.; Gardiner, David M.; and Voss, S. Randal, "Characterization of in vitro Transcriptional Responses of Dorsal Root Ganglia Cultured in the Presence and Absence of Blastema Cells from Regenerating Salamander Limbs" (2014). Biology Faculty Publications. 93.
Table S1. List of 1541 probe sets that were identified as differentially expressed between dorsal root ganglia sampled on day 0 and day 5. Columns indicate if a gene was significantly upregulated or downregulated for a given statistical contrast. A “1” indicates that the probe set was differentially expressed and the corresponding change was detected, while a “0” indicates there was no significant change.