Regulatory effect of rapamycin on recruitment and function of myeloid-derived suppressor cells in heart failure

Background: Immune response and inflammation play important roles in the physiological and pathophysiological processes of heart failure (HF). In our previous study, myeloid-derived suppressor cells (MDSCs), a heterogeneous group of immature myeloid cells with anti-inflammatory and immunosuppressive functions, were shown to exert cardioprotective effects in HF. The pharmacological targeting of MDSCs using rapamycin may emerge as a promising strategy for the prevention and treatment of HF. However, the specific mechanisms underlying rapamycin-induced MDSC accumulation remain unclear. Our study aimed to clarify the effects of rapamycin on the recruitment and function of MDSCs in HF, exploring new therapeutic options for the prevention and treatment of HF. Methods: We used transverse aortic constriction surgery and isoproterenol injection to establish HF models. Flow cytometry, reverse transcription polymerase chain reaction, transcriptomics and western blot were used to explore the regulation of rapamycin on recruitment and function of MDSCs in HF. Furthermore, rapamycin and granulocyte-macrophage colony-stimulating factor (GM-CSF) were combined to induce exogenous MDSCs from bone marrow cells. Results: Rapamycin promotes the recruitment of MDSCs by inhibiting their maturation and differentiation via suppression of the Wnt signaling in HF mice and enhanced the immunosuppressive function of MDSCs via the NF kappa B signaling. Furthermore, exogenous MDSCs induced by rapamycin and GM-CSF can significantly alleviate transverse aortic constriction-induced cardiac dysfunction. Conclusions: The pharmacological targeting of MDSCs using rapamycin is a promising strategy for the prevention and treatment of HF.