Functional Optic Tract Rewiring via Subtype- and Target-specific Axonal Regeneration and Presynaptic Activity Enhancement (scRNA-Seq)

Mechanisms underlying functional axonal rewiring after adult mammalian central nervous system (CNS) injuries remain unclear partially due to limited models. Using a mouse intracranial pre–olivary pretectal nucleus (OPN) optic tract injury model, we demonstrate that Pten/Socs3 knockout and CNTF expression in retinal ganglion cells (RGCs) promotes optic tract regeneration and reinnervation into OPN. Revealed by transmission electron microscopy, trans-synaptic labeling and electrophysiology, functional synapses are formed in OPN mainly by intrinsically photosensitive RGCs, thereby partially restoring the pupillary light reflex (PLR). Furthermore, combining with Lipin-1 knockdown accelerates the recovery and achieves functional reconnection in the chronic injury paradigm. PLR can be further boosted by increasing either RGC photosensitivity with melanopsin or optic tract presynaptic release with a voltage-gated calcium channel modulator, the latter of which also improves corticospinal-tract-sprouting-induced functional recovery after stroke. These findings highlight the importance of neuronal types and presynaptic activity for functional reconnection after CNS injuries.