Fig. 1

NAD⁺ content, NRK1/2 and Slc12a8 expression. A and B Mice received saline, FIP or NMN (500 mg/kg, i.p.). Six hours later, NAD⁺ levels in heart (A) and lung tissues (B) were determined. C Macrophages were treated with NMN (500 µM), LPS (100 ng/mL) or saline. NAD⁺ levels were analyzed. D Endothelial cells were treated with LPS-conditioned medium (LCM), PBS-conditioned medium (PCM) or NMN. Twenty-four hours later, NAD⁺ levels in endothelial cells were measured. E–M Mice were challenged with FIP or saline. Six hours later, heart, lung and liver tissues were collected. The mRNA levels of NRK1/2 and Slc12a8 were quantified by real-time PCR in heart (E–G), lung (H–J) and liver tissues (K–M). (N) Neutrophils were incubated with NMN for 24 h and NAD⁺ were then determined in neutrophils. Data are mean ± SD, n = 3–6 in each group. *P < 0.05 vs saline or vehicle and #P < 0.05 vs saline, feces or LCM (One-way analysis of variance followed by Newman–Keuls test)