[HTML][HTML] Hypoxia-independent angiogenesis in adipose tissues during cold acclimation

Y Xue, N Petrovic, R Cao, O Larsson, S Lim, S Chen… - Cell metabolism, 2009 - cell.com
Y Xue, N Petrovic, R Cao, O Larsson, S Lim, S Chen, HM Feldmann, Z Liang, Z Zhu…
Cell metabolism, 2009cell.com
The molecular mechanisms of angiogenesis in relation to adipose tissue metabolism remain
poorly understood. Here, we show that exposure of mice to cold led to activation of
angiogenesis in both white and brown adipose tissues. In the inguinal depot, cold exposure
resulted in elevated expression levels of brown-fat-associated proteins, including
uncoupling protein-1 (UCP1) and PGC-1α. Proangiogenic factors such as VEGF were
upregulated, and endogenous angiogenesis inhibitors, including thrombospondin, were …
Summary
The molecular mechanisms of angiogenesis in relation to adipose tissue metabolism remain poorly understood. Here, we show that exposure of mice to cold led to activation of angiogenesis in both white and brown adipose tissues. In the inguinal depot, cold exposure resulted in elevated expression levels of brown-fat-associated proteins, including uncoupling protein-1 (UCP1) and PGC-1α. Proangiogenic factors such as VEGF were upregulated, and endogenous angiogenesis inhibitors, including thrombospondin, were downregulated. In wild-type mice, the adipose tissues became hypoxic during cold exposure; in UCP1−/− mice, hypoxia did not occur, but, remarkably, the augmented angiogenesis was unaltered and was thus hypoxia independent. Intriguingly, VEGFR2 blockage abolished the cold-induced angiogenesis and significantly impaired nonshivering thermogenesis capacity. Unexpectedly, VEGFR1 blockage resulted in the opposite effects: increased adipose vascularity and nonshivering thermogenesis capacity. Our findings have conceptual implications concerning application of angiogenesis modulators for treatment of obesity and metabolic disorders.
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