Delivery Of Nucleic Acid Drugs With Cationic Lipid-Assisted Nanoparticles To Interfere Function Of Immune Cells For Immunotherapy

Cancer has become one of the major diseases in the world that threaten human health.There are increasing evidences that malignant tumors have a complex microenvironment consisting of tumor cells and various types of immune cells.Tumor-associated macrophages(TAMs),derived from circulating Ly6Ch' monocytes constitute the most important part of tumor infiltrating immune cells in almost all cancer types and contribute to tumor progression,angiogenesis,metastasis,immunosuppression and therapeutic resistance.Interrupting the key signaling pathway that targets monocyte recruitment to tumor tissue such as CCL2-CCR2,is one of the most promising pathways for tumor microenvironment regulation and cancer therapy.One critical issue in monocyte-based immune function intervention and treatment is how to effectively deliver therapeutic agents to monocytes.Studies have shown that the surface properties of nanocarriers can significantly affect their interaction with immune cells.By regulating the properties of the nanocarriers,the ability to interfere with immune cell function and the therapeutic effect can be improved.In this project,we systematically studied the relationship between the surface potential of nanocarriers and their biodistribution in monocytes in vivo,and screened and identified a delivery system suitable for monocyte targeting.The results show that cationic lipid-assisted nanoparticles have a higher tendency to accumulate in monocytes compared to other neutral nanoparticles.Further,we demonstrated that cationic nanoparticles(CNP/siCCR2)encapsulating siCCR2 small interfering RNA can more effectively alter the immunosuppressive tumor microenvironment and exhibit excellent antitumor effects in an orthotopic mouse breast cancer model.Organ transplantation is the only effective treatment for end-stage organ failure.However,this method has been plagued by rej ection.Immunological rej ection is mainly caused by T cell-mediated responses.Dendritic cells(DCs)are professional antigen-presenting cells and blocking the co-stimulatory signaling molecule CD40 in DCs inhibits T cell activation and induces transplant tolerance.In this project,to reduce graft rejection,we prepared Cas9 mRNA(mCas9)and a guide RNA(gCD40)targeting the costimulatory molecule CD40 and encapsulated in cationic lipid-assisted nanoparticles(CLANs).CLAN can efficiently deliver mCas9/gCD40 to DCs and disrupt the CD40 gene in DCs both in vitro and in vivo.After intravenous injection into an acute mouse skin graft model,CLANmCas9/gCD40-mediated disruption of the CD40 gene significantly inhibited T cell activation,thereby reducing graft damage and prolonging graft survival.This part of the work provides a promising strategy for the delivery of CRISPR/Cas9-based nanoparticles to interfere with DC function for abating transplant rejection.