Inhibition of pyruvate oxidation as a versatile stimulator of the hair cycle in models of alopecia.

Hair follicle stem cells (HFSCs) are known to be responsible for the initiation of a new hair cycle, but typically remain quiescent for very long periods. In alopecia, or hair loss disorders, follicles can be refractory to activation for years or even permanently. Alopecia can be triggered by autoimmunity, age, chemotherapeutic treatment, stress, disrupted circadian rhythm or other environmental insults. We previously showed that hair follicle stem cells and the hair cycle can be manipulated by regulation of pyruvate entry into mitochondria for subsequent oxidation to fuel the TCA cycle in normal adult mice with typical hair cycling. Here, we present new data from our efforts to develop murine models of alopecia based on environmental triggers that have been shown to do the same in human skin. We found that inhibition of pyruvate transport into mitochondria can accelerate the hair cycle even during refractory hair cycling due to age, repeated chemotherapeutic treatment and stress. Hair cycle acceleration in these alopecia models led to the formation of histologically normal hair follicles within 30-40 days of treatment without any overt signs of toxicity or deleterious effects. Therefore, we propose inhibition of pyruvate entry into mitochondria as a versatile treatment strategy for alopecia in humans.