Fig. 4.

NAMPT expression pattern, production and secretion by leucocyte subpopulations. a The expression of NAMPT mRNA was significantly higher in PBL than in all other tissues, including adipose tissue and liver (p _Anova < 0.0001). Significance was calculated by one-way ANOVA with Dunnett’s post test (compared with PBL). b The mRNA expression of NAMPT was more than fivefold higher in granulocytes and monocytes compared with lymphocytes. c Higher amounts of NAMPT protein were detected in cell lysates of granulocytes and monocytes compared with lymphocytes. d Granulocytes secreted more than 22-fold higher amounts of NAMPT protein into cell culture supernatant fractions (n = 12) when normalised to total protein. Serum concentrations of NAMPT were highly correlated to leucocyte count in particular to neutrophil granulocyte (e) (r = 0.92, p = 0.009) and monocyte (f) (r = 0.94, p = 0.005) count but not to lymphocyte count (g) (n = 6, p = 0.41). h NAMPT enzymatic activity was present in cell lysates and supernatant fractions of all leucocyte subpopulations (n = 5). i SIRT1 mRNA expression was significantly higher in granulocytes compared with lymphocytes and monocytes (n = 12). j The release of NAMPT was significantly increased from monocytes and granulocytes after stimulation with 1 μg/ml LPS for 24 h in n = 3 independent experiments. Data are mean ± SEM. Statistical significance was assessed by Student’s t test and Pearson correlation analysis: *p < 0.05, **p < 0.01, ***p < 0.0001. G, granulocytes; L, lymphocytes; M, monocytes; PBL, peripheral blood leucocytes