Figure 3. Deficiency of α₄ integrin promotes beige adipogenesis of white AT in obesity.

a) Energy expenditure (EE, expressed as kcal/h) of obese Cre⁺α₄^f/f (n=4 mice) and Cre⁻α₄^f/f (n=5 mice) mice was assessed by a metabolic cage monitoring system for 3 days (left). Average EE in light and dark period is also displayed (right). b) Gene expression in SAT of obese Cre⁺α₄^f/f or Cre⁻α₄^f/f mice was evaluated by qPCR (n=8 mice for Cre⁺α₄^f/f and 10–11 mice for Cr⁻α₄^f/f). 18S expression was used for normalization of mRNA expression and the respective gene expression of obese Cre⁻α₄^f/f mice was set as 1. c) Representative cropped blot images showing immunoblotting for UCP1 (and actin) in SAT from 2 obese Cre⁺α₄^f/f and 2 Cre⁻α₄^f/f mice. Actin was used as loading control. d–f) Obese Cre⁺ α₄^f/for Cre⁻α₄^f/f mice were challenged with a temperature of 4°C for 12 h. d) Core temperature of obese Cre⁺ α₄^f/f (n=4 mice) or Cre⁻α₄^f/f (n=6 mice) mice during cold exposure. e) Representative cropped blot images showing immunoblotting (left) for UCP1 (and actin) in SAT of 2 obese Cre⁺ α₄^f/fand 2 obese Cre⁻α₄^f/f mice exposed to cold. Densitometric analysis (right) of UCP1 immunobloting from a total of 4 Cre⁺ α₄^f/f mice and 5 Cre⁻α₄^f/f mice is shown. The protein amounts of UCP1 were normalized against actin; the UCP1 amounts (normalized over actin) in SAT from Cre⁻α₄^f/f mice were set as 1. f) UCP1 staining in SAT from Cre+α₄^f/f or Cre⁻α₄^f/f mice exposed to cold. g) Mature white and brown adipocytes were isolated from SAT and BAT of obese mice (n=6 mice) after tissue digestion and Vcam1 mRNA expression was determined. 18S expression was used for normalization and Vcam1 expression of SAT was set as 1. Data are presented as mean ± SEM. Data in (a), (d) and (e) are from one experiment; data in (b) are pooled from 3 experiments; data in (c) and (g) are representative of 2 experiments. In (f) representative images are from analysis performed on 5 ⁻α₄^f/f and 4 Cre⁺α₄^f/f mice. *P < 0.05. ANCOVA in (a) and Mann-Whitney U-test in (b)–(g).

Abbreviations: Ucp1, uncoupling protein 1; Cidea, cell death-inducing DNA fragmentation factor-like effector A; Cox8b, cytochrome c oxidase subunit 8b; Cox7a1, Cytochrome c oxidase subunit 7A1; Acsl1, acyl-CoA synthetase long-chain family member 1