Therapeutic use of R-spondins to augment the cerebrovascular and neuronal Wnt signaling and improve stroke outcome in mice [scRNA-Seq]

Wnt signaling is critical for blood-brain barrier function, neuronal survival and adult neurogenesis, yet Wnt proteins are poorly suited as therapeutics for stroke due to production and pharmacokinetic challenges. Here, we show that R-spondins (RSPOs), a family of easily produced and secreted proteins capable of robustly augmenting Wnt signaling, are widely expressed in adult mouse brain and upregulated upon ischemia and reperfusion injury. Neutralizing endogenous RSPOs with the soluble ectodomains of their membrane receptors LGR5, ZNRF3 and RNF43 increased cerebral infarction in a murine stroke model. Conversely, systemic administration of RSPOs substantially reduced cerebral infarction and improved neurological outcomes. The neuroprotective effects of RSPOs were dependent on LGR4/ZNRF3-mediated augmentation of canonical Wnt/?-catenin signaling in endothelial and neuronal cells, which in turn promoted blood-brain barrier integrity, neuronal PDGF-CC expression and survival. Further, RSPOs promotes the proliferation and expansion of neural stem/progenitor cells and post-stroke neurogenesis. Thus, we identify a previously unknown neuroprotective and pro-neurogenic mechanism and describe the therapeutic potential of recombinant RSPOs in ischemic stroke. Overall design: Examination of gene regulation by Wnt3a plus Rspondin 1 in Neural stem cells.