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

Although Wnt signaling is critical for blood-brain barrier function, neuronal survival and adult neurogenesis, Wnt proteins are poorly suited as therapeutics for stroke given production and pharmacokinetic challenges. Here, we show that R-spondins (RSPOs), a family of easily produced secreted proteins that robustly augment Wnt signaling, were widely expressed in adult mouse brain and upregulated upon ischemia and reperfusion injury. Neutralizing endogenous RSPOs with their membrane receptor LGR5 and ZNRF3/RNF43 soluble ectodomains 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 canonical Wnt/-catenin signaling in the endothelia, neuronal cells and neural stem/progenitor cells, all of which contributed synergistically to reduce cerebral ischemia/reperfusion injury. Thus, we identified a previously unknown neuroprotective mechanism and the therapeutic potential of recombinant RSPOs in ischemic stroke. Examination of gene regulation by Wnt3a plus Rspondin 1 in rat primary neuron under oxygen glucose deprivation (OGD)