Aging of white adipose tissue (WAT) is associated with reduced insulin sensitivity, which contributes to whole-body glucose intolerance. WAT aging in mice impairs cold-induced beige adipocyte recruitment (beiging), which has been attributed to the senescence of adipose progenitor cells. Tumor suppressor p53 has also been implicated in WAT aging. However, whether p53-related cellular aging in mature white adipocytes is causative of age-impaired WAT beiging remains unknown. It is also unclear whether transient p53 inhibition can rescue WAT beiging. Herein, we report that p53 increased in adipose tissues of 28-wk-old (aged) mice with impaired beiging capability. Cold exposure decreased p53 in beiging WAT of young mice but not in aged mice. In aged mice, inducible p53 ablation in differentiated adipocytes restored cold-induced WAT beiging and augmented whole-body energy expenditure and insulin sensitivity. Transient pharmacological inhibition of p53 led to the same beneficial effects. Mechanistically, cold exposure repressed autophagy in beiging WAT of young mice yet increased autophagy in aged WAT. p53-ablation reduced microtubule-associated protein light chain 3-mediated mitochondria clearance (mitophagy) and hence facilitated the increase of mitochondria during beiging. These findings suggest that p53-induced mitophagy in aged white adipocytes impedes WAT beiging and may be therapeutically targeted to improve insulin sensitivity in aged WAT.-Fu, W., Liu, Y., Sun, C., Yin, H. Transient p53 inhibition sensitizes aged white adipose tissue for beige adipocyte recruitment by blocking mitophagy.
Keywords: aging; autophagy; diabetes; insulin sensitivity; mitochondria.