Figure 2. Hepatocyte-specific overexpression of Nampt promotes liver regeneration.

Mice carrying a Cre-inducible allele of Nampt in addition to Alb-Cre (denoted as N^Albcre) and littermate controls (N) were subjected to 2/3 partial hepatectomy and analyzed 48 hours later.

(A) Nampt overexpression is driven by the CAGGS promoter, separated from the NAMPT transgene by a STOP cassette flanked with loxP sites. Under the influence of Cre recombinase, the STOP cassette is removed, resulting in overexpression of Nampt. The construct was inserted at the ColA1 locus. Left: Nampt protein and mRNA expression in liver. Right: Immunofluorescence showing overexpression of Nampt in peri-portal and peri-central venous areas of N^Albcre mice. Inset shows an enlarged view of N^Albcre.

(B) Left: Photographs of regenerating livers. Right: Proliferating hepatocytes identified by EdU detected by immunofluorescence (green) and counterstained with DAPI (blue) with quantification of EdU positive hepatocytes (n=4–5/group). Inset shows an enlarged view of N^Albcre.

(C) Left: Liver to body weight ratios. Right: Fasting blood glucose.

(D) Liver NAD content before and after PHx.

(E) Mitotic index as determined by counting mitotic figures in hepatocytes under high power in H&E stained sections.

(F) Left: Representative liver sections stained with H&E. Right: Hepatic lipid content as determined by Oil Red O and triglyceride assay.

Error bars represent S.E.M. *, p < 0.05; **, p < 0.01; ***, p < 0.001.