Model illustration of enhanced mitochondrial transport critical for mature neurons to regain axonal regenerative capacity. (A) Although mitochondrial transport in WT axons progressively declines with maturation, axonal injury depolarizes local mitochondria, thus leading to energy deficits. Energy deficits may reflect the intrinsic restriction of mature axons to regenerate after injury. (B) Enhanced local ATP supply via healthy mitochondrial flux into injured axons is critical to meet metabolic requirements for axonal regeneration. Enhancing mitochondrial transport in snph KO axons not only helps remove those dysfunctional mitochondria, but also replenishes healthy ones to the injured axons, thus recovering mitochondrial integrity and rescuing energy deficits.