Thrombopoietin receptor agonist eltrombopag alleviates cognitive impairment via NRG1/ErbB4 signaling

Background Patients with minimal hepatic encephalopathy (MHE) show mild cognitive impairments. Thrombopoietin (TPO) has been shown to be neuroprotective. This study aimed to explore the therapeutic effect of Thrombopoietin receptor agonist eltrombopag (ELT) on MHE and the involvement of NRG1 signaling using primary rat neurons and a MHE rat model. Methods We explored the effects of ELT stimulation on NRG1/ErbB4 signaling and synapse formation in the primary rat neurons. Furthermore, we explored the cerebral TPO expression level and the effect of TPO replacement therapy in an MHE rat model. Results The results showed that ELT stimulation activated NRG1/ErbB4 signaling and enhanced synaptic protein expression in the primary rat neurons via sirtuin 1. An anti-NRG1 antibody, ErbB4 inhibitor, or knockdown of NRG1 or ErbB4 could significantly abolish ELT-induced upregulation of synaptic protein expression in the primary rat neurons. MHE rats had significantly decreased cerebral ELT expression compared with normal rats. ELT activated NRG1/ErbB4 signaling in MHE rat brains. Administration or overexpression of ELT or TPO promoted synapse formation and alleviated cognitive impairments in MHE rats. Conclusions These data suggest that ELT promotes synapse formation in vitro and in vivo via activating NRG1/ErbB4 signaling, serving as a promising therapeutic agent for MHE treatment.