Figure 6.

Spermidine downregulates phosphorylation of STAT1 and STAT3 more efficiently in IFN-γ treated THP-1 cells and IBD-patient derived PBMC carrying the PTPN2 C-variant. THP-1 cells were stably transfected with lentiviral constructs containing the T (“WT”) or the C (“variant”) allele in PTPN2 SNP rs1893217. After selection of clones with stable expression of the lentiviral DNA, the cells were treated for 30 minutes with 100 ng/mL IFN-γ and/or 10 µM spermidine. (A) Representative Western blots show the protein levels of PTPN2, (B) PTPN2 enzymatic activity and representative Western blot pictures from immunoprecipitations used for the activity assay, (C) representative Western blots and densitometry of STAT1 and STAT3 phosphorylation levels after 30 minutes. Data represent means (n = 3) and standard deviation. PBMC from healthy controls (HC, black bars, homozygous for the T allele, n = 5), or IBD patients homozygous for the T allele (TT, blue bars, n = 6) or heterozygous (CT, red bars, n = 5) for the PTPN2 SNP rs1893217 were treated for 30 minutes with 100 ng/mL IFN-γ and/or 10 µM spermidine. Representative Western blots and densitometry analysis show phosphorylation level of (D) STAT1 and (E) STAT3. Data represent means and standard deviations. Analysis of variance ANOVA followed by post hoc Tuckey; asterisks indicate significant differences (*P < 0.05, ***P < 0.001)