Figure 1

Characterization of the Neu2 KO mouse model. (A) Confirmation of Neu2 gene KO in vivo by T7E1 digestion assay. PCR amplicons of the WT Neu2 sequence were added to discriminate the homozygous Neu2 KO from WT. Digested bands are marked by red arrowheads. (B) Validation of homozygous Neu2 gene KO by Sanger sequencing. Deleted bases in the KO mouse are marked by a red block with dashes. (C) Histological localization of Neu2 and sialylated glycoproteins by Neu2 immunostaining and SNL staining on paraffin-embedded slides of liver and muscle from adult male mice. Scale bar: 100 μm. (D) Biochemical analysis of triglyceride content in serum samples from littermates in the young and adult mice. Young (9–10 w); WT: n = 6; Neu2 KO: n = 7, adult (23–25 w) ; WT: n = 6; Neu2 KO: n = 5. (E,F) Biochemical quantification of the free fatty acid (FFA) content in adult (23–25 w) serum and elderly (41–55 w) liver samples from littermates. (E) Serum FFA content from adult mice; WT: n = 5; Neu2 KO: n = 5, (F) FFA content from liver tissues of the elderly (41–55 w) mice. WT (n = 7); Neu2 KO (n = 5). (G) Representative lipid droplet marker OXPAT immunostaining and quantification in the liver from elderly (41–55 w) male mice. WT (n = 4); Neu2 KO (n = 4). Scale bar: 100 μm. (H) Representative H&E images and quantification of steatosis in the liver from elderly (41–55 w) male mice. WT (n = 4); Neu2 KO (n = 4). Scale bar: 100 μm. (I) Representative images and quantification of liver fibrosis from elderly (41–55 w) male mice. WT(n = 4); Neu2 KO (n = 4). Scale bar: 100 μm. All studies were conducted in control and Neu2 KO mice among young (9–10 w), adult (23–25 w), and elderly (41–55 w) male littermates, unless otherwise indicated. Data are expressed as the mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.0001 by Student’s t-test.