GDNPs reprogram macrophages to regulate arginase-1 release for ameliorating T cell exhaustion in tumor microenvironment

Lines of evidence indicate that, immune checkpoints (ICs) inhibitors enhance T cell immune response to exert anti-tumor effects. However, T cell exhaustion is still a major obstacle to antitumor immunotherapy in colorectal cancer patients. Our previous studies showed that ginseng-derived nanoparticles (GDNPs) inhibited the growth of various tumors by reprograming tumor-associated macrophages (TAMs) and downregulated the ICs expression on T cells in tumor microenvironment (TME), but the underlying effector mechanisms remained unclear. In this study, we demonstrated that GDNPs reprogramed TAMs via reducing arginase-1 (ARG1) production. Moreover, normalized arginine metabolism ameliorate T cell exhaustion through mTOR-T-bet axis, resulting in reduced ICs expression and enhanced CD8+ T cells expansion. Together, these results provide new insights in understanding the mechanisms involved in reversing T cell exhaustion, which may facilitate the development of new therapeutic strategy for cancer treatment. Single cell RNA seqencing data of six samples from six colon cancer bearing C57 mice treated with ginseng-derived nanoparticles. Each samples contain one sample from solid tumor of each tumor bearing mouse. Mouse tumor tissues were scissored into 5 mm pieces and incubation with 100 μg/mL Liberase and 0.2 mg/mL DNase Ⅰ in PBS for 45 min at 37°C. After digestion, 70 μm nylon net was centrifuged at 300 g for 5 min. Subsequently, the supernatants were discarded, and the cell pellets were suspended in 1 mL PBS. To remove red blood cells, 2 mL of GEXSCOPETM red blood cell lysis buffer (Singleron) was added, and cells were incubated at 25 °C for 10 min. The solution was then centrifuged at 500 × g for 5 min and resuspended in PBS.Single-cell suspensions (1×105 cells/mL) with PBS were loaded into microfluidic devices using the Singleron Matrix®Single Cell Processing System (Singleron). Subsequently, the scRNA-seq libraries were constructed according to the protocol of the GEXSCOPE® Single Cell RNA Library Kits (Singleron). Individual libraries were diluted to 4 nM and pooled for sequencing. At last, pools were sequenced on Illumina HiSeq X with 150 bp paired end reads.