Context‐Dependent Roles of ANGPTL2 ‐Mediated Inflammaging in Tissue Homeostasis, Pathological Tissue Remodeling, and Longevity

FIGURE 1. ANGPTL2 deficiency shortens lifespan in a mouse model of high‐fat diet‐induced premature aging. WT and Angptl2 −/− mice were fed an HFD, starting at 6 weeks of age. (a) Kaplan–Meier survival curves of ND‐fed male WT (n = 56) and ND‐fed male Angptl2 −/− (n = 116) mice. ns, not significant (p > 0.05), log‐rank test. (b) Kaplan–Meier survival curves of ND‐fed female WT (n = 59) and ND‐fed female Angptl2 −/− (n = 74) mice. ns, not significant (p > 0.05), log‐rank test. (c) Kaplan–Meier survival curves of HFD‐fed male WT (n = 58) and HFD‐fed male Angptl2 −/− (n = 46) mice. ****p < 0.0001, log‐rank test. (d) Kaplan–Meier survival curves of HFD‐fed female WT (n = 66) and HFD‐fed female Angptl2 −/− (n = 46) mice. ns, not significant (p > 0.05), log‐rank test. (e, f) Comparison of body weights over time in the indicated groups (ND: Up to 120 weeks; HFD: Up to 90 weeks). Data are means ± SE; n = 56, ND‐fed male WT; n = 113, ND‐fed male Angptl2 −/−; n = 68, HFD‐fed male WT; n = 42, HFD‐fed male Angptl2 −/−; n = 59, ND‐fed female WT; n = 74, ND‐fed female Angptl2 −/−; n = 66, HFD‐fed female WT; n = 45, HFD‐fed female Angptl2 −/− mice. ****p < 0.0001; ***p < 0.001; **p < 0.01; *p < 0.05,…

FIGURE 2. ANGPTL2 deficiency attenuates high‐fat diet‐induced systemic inflammation. (a) Schematic illustrating experimental design of the HFD‐induced premature aging model. (b) Comparison of body weights over time of HFD‐fed WT (n = 14) and HFD‐fed Angptl2 −/− (n = 7) mice. Data are means ± SD. **p < 0.01, two‐way ANOVA test. (c) qRT‐PCR analysis of transcripts of indicated genes in colon, eWAT, heart, liver, kidney, and lung tissues from HFD‐fed WT (n = 22) and HFD‐fed Angptl2 −/− (n = 15) mice at 30 weeks of age. WT levels were set to 1. Data are means ± SD. ns, not significant (p > 0.05); ****p < 0.0001; ***p < 0.001; **p < 0.01; *p < 0.05, unpaired t‐test, following outlier removal.

FIGURE 3. ANGPTL2 supports intestinal regeneration under metabolic stress. WT and Angptl2 −/− mice were fed an HFD as seen in Figure 2a, starting at 6 weeks of age. (a, b) Representative images of colons (a) and colon length (b) from ND‐ or HFD‐fed WT and Angptl2 −/− mice at 30 weeks of age. Scale bar, 1 cm. Data are means ± SD: n = 5, ND‐fed WT group; n = 5, ND‐fed Angptl2 −/− group; n = 27, HFD‐fed WT group; n = 23, HFD‐fed Angptl2 −/− group. ns, not significant (p > 0.05); ****p < 0.0001; **p < 0.01, one‐way ANOVA test followed by Tukey's multiple comparison test. (c) Representative images of H&E‐stained colon tissue from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 50 μm. (d) The number of crypts as quantified using H&E‐stained sections shown in (c). Each data point represents the average number of crypts in a single field of view. Multiple areas in section per mouse were quantified. Data are means ± SD. *p < 0.05, unpaired t‐test. (e–g) qRT‐PCR analysis of transcripts of indicated genes in colon tissues from HFD‐fed WT (n = 22) and HFD‐fed Angptl2 −/− (n = 15) mice at 30 weeks of age. WT levels were set to 1. Data are means ± SD. ns, not significant (p >…

FIGURE 4. ANGPTL2 promotes pathological tissue remodeling in adipose tissue and heart. WT and Angptl2 −/− mice were fed an HFD as seen in Figure 2a, starting at 6 weeks of age. (a, b) Representative images of H&E‐stained eWAT (a) and adipocyte area (b) from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 250 μm. Data are means ± SD: n = 22, HFD‐fed WT group; n = 15, HFD‐fed Angptl2 −/− group. ***p < 0.001, unpaired t‐test. (c, d) qRT‐PCR analysis of transcripts of indicated genes in eWAT from HFD‐fed WT (n = 22) and HFD‐fed Angptl2 −/− (n = 15) mice at 30 weeks of age. WT levels were set to 1. Data are means ± SD. ns, not significant (p > 0.05); *p < 0.05, unpaired t‐test. (e) Representative images of H&E‐stained heart tissues from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 1 mm. (f, g) Representative images of WGA‐stained heart tissues (f) and cardiomyocyte size (g) from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 50 μm. Data are means ± SD: n = 22, HFD‐fed WT group; n = 15, HFD‐fed Angptl2 −/− group. ****p < 0.0001, unpaired t‐test. (h–j) qRT‐PCR analysis of transcripts of indicated genes in heart tissues from…

FIGURE 5. Organ‐specific roles of ANGPTL2 in regulating tissue fibrosis. WT and Angptl2 −/− mice were fed an HFD as seen in Figure 2a, starting at 6 weeks of age. (a) Representative images of H&E‐stained liver tissue from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 500 μm. (b, c) Representative images of Masson's trichrome‐stained liver tissues (b) and fibrotic areas (c) from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 500 μm. Data are means ± SD: n = 22, HFD‐fed WT group; n = 15, HFD‐fed Angptl2 −/− group. **p < 0.01, unpaired t‐test. (d, e) qRT‐PCR analysis of transcripts of indicated genes in liver tissues from HFD‐fed WT (n = 22) and HFD‐fed Angptl2 −/− (n = 15) mice at 30 weeks of age. WT levels were set to 1. Data are means ± SD. ns, not significant (p > 0.05); ***p < 0.001; *p < 0.05, unpaired t‐test, following outlier removal. (f) qRT‐PCR analysis of Lcn2 transcripts in kidney tissues from HFD‐fed WT (n = 22) and HFD‐fed Angptl2 −/− (n = 15) mice at 30 weeks of age. WT levels were set to 1. Data are means ± SD. ***p < 0.001; *p < 0.05, unpaired t‐test. (g, h) Representative images of Masson's trichrome‐stained kidney tissues (g)…

FIGURE 6. ANGPTL2 promotes lymphocyte aggregation in the lung. WT and Angptl2 −/− mice were fed an HFD as seen in Figure 2a, starting at 6 weeks of age. (a) Representative images of H&E‐stained lung tissue from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 500 μm. Arrowheads indicate a BALT. (b) Proportion of lung tissues having BALT shown in (a). n = 22, HFD‐fed WT group; n = 15, HFD‐fed Angptl2 −/− group. *p < 0.05, Fisher's exact test. (c, d) Representative images of Masson's trichrome‐stained lung tissues (c) and fibrotic areas (d) from HFD‐fed WT and HFD‐fed Angptl2 −/− mice at 30 weeks of age. Scale bar, 500 μm. Data are means ± SD: n = 22, HFD‐fed WT group; n = 15, HFD‐fed Angptl2 −/− group. **p < 0.01, unpaired t‐test. (e, f) qRT‐PCR analysis of transcripts of indicated genes in lung tissues from HFD‐fed WT (n = 22) and HFD‐fed Angptl2 −/− (n = 15) mice at 30 weeks of age. WT levels were set to 1. Data are means ± SD. ns, not significant (p > 0.05); ***p < 0.001; *p < 0.05, unpaired t‐test, following outlier removal.

FIGURE 7. Schematic summary of organ‐specific effects of ANGPTL2 deficiency in high‐fat diet‐fed mice. The impact of ANGPTL2 deficiency on various organs including the colon, adipose tissue, heart, liver, kidney, and lung. The overall functional role of ANGPTL2 in each organ is classified as beneficial, detrimental, or controversial.