Fig. 6

L-citrulline promotes CXCL3 expression through H3Cit to exert the radioprotective effect. (A) The Schematic graph of ChIP-Seq and RNA-Seq. (B) The PCA analysis of IEC-6 cells treated with L-citrulline compared with control group. (C) The volcano plot of mRNAs between L-citrulline treated group and control group in IEC-6 cells, fold-change > 1.5, P < 0.05. (D) The heatmap of mRNAs between L-citrulline treated group and control group. (E) KEGG analysis of the differential mRNAs in L-citrulline treated Vs control group. (F) Specific peaks of genomic binding were identified by H3Cit17-ChIP-Seq in IEC-6 cells. (G) Distribution of H3Cit17 ChIP-Seq reads from control (blue) and L-citrulline-treated (pink) IEC-6 cells with ± 10 kb of TSS. (H) Localization of H3Cit17-bound peaks from ChIP-Seq analysis in IEC-6 cells treated with L-citrulline. (I) HOMER de novo motif enrichment analyses of H3Cit17 binding peaks. The top 10 significantly enriched binding motifs and their matched TF family were presented. (J) Combining the data from ChIP-Seq and RNA-Seq, 31 mRNA were differentially expressed with H3Cit17 enrichment. (K) The expression changes of H3Cit17-target genes (Aebp1, Cxcl3, Herc6, Slc16a6) in IEC-6 cells treated with L-citrulline. (L) A diagram indicates the relative positions of transcription factors of Cxcl3 gene, three pair of primers were used. (M) ChIP analysis of transcription factors binding site (primer #2) in Cxcl3 gene. (N) The effects of CXCL3 treatment on cell viability with or without radiation. (O) Western blotting analysis of Cxcl3 in IEC-6 cells. (P) Effect of Cxcl3 on radiation sensitivity as determined by a colony formation assay followed different dose of radiation. (Q) The clonogenic survival curve of IEC-6 cells was measured. The data are shown as the mean ± SEM for three independent experiments. *P < 0.05; **P < 0.01