Combining an alarmin HMGN1 peptide with PD-L1 blockade facilitates stem-like CD8⁺ T cell expansion and results in robust antitumor effects

Abstract

BackgroundThe expansion of intratumoral stem-like CD8+ T (Tstem) cells provides a potential approach to improving the therapeutic efficacy of immune checkpoint blockade (ICB). Thus, here we demonstrate a strategy to facilitate Tstem cell expansion by combining an alarmin high-mobility group nucleosome binding domain 1 (HMGN1) peptide with programmed death-ligand 1 (PD-L1) blockade.MethodsThe antitumor effects of HMGN1, anti-PD-L1 antibody, and their combined treatment were monitored in the B16F10, LLC, Colon26, or the EO771 tumor-bearing mice. The comprehensive immunologic analyses, such as high-dimensional flow cytometry, transcriptome analysis, and single-cell RNA sequencing, were used to investigate the cellular and molecular mechanisms of antitumor immune responses after treatments.ResultsThe HMGN1 peptide synergizes with PD-L1 blockade in augmenting the number of mature DCs enriched in immunoregulatory molecules (mregDCs) in tumors, and enhancing their MHC class I antigen-presenting program, which is correlated with the expansion of intratumoral Tstem cells, specifically promoting the Tstem cells but restricting terminally exhausted CD8+ T (Tex) cells, owing to the regulatory molecules expressed on mregDCs.ConclusionOur results indicate that HMGN1 peptide serves as an immunoadjuvant to promote effective anti-PD-L1 immunotherapy and implicate that mregDCs play a role beyond facilitating Tstem cell expansion.

AMPK activation reverts mouse epiblast stem cells to naive state

“…TAS-Seq was then performed. Sequencing was entrusted to ImmunoGeneTeqs ( Chen et al., 2020 ). Adapter trimming of the sequencing data was performed using cutadapt 2.10.…”

Phagocytosing differentiated cell-fragments is a novel mechanism for controlling somatic stem cell differentiation within a short time frame

“…To verify the lineage-specific differentiation induced by phagocytosing DDCs, naïve h-Muse cells (Naïve-Muse cells) as well as h-Muse cells incubated with m-cardiomyocyte DDCs (Phago-cardio-Muse), r-neural cell DDCs (Phago-neuro-Muse), or r-hepatic cell DDCs (Phago-hepa-Muse) were subjected to scRNA-seq at 1 week. Single cells from each sample were processed for scRNA-seq using the TAS-seq protocol [15]. Overall, 1752 cells passed quality control with a mean of 5939 genes/cell and 87,322 reads/cell.…”

TAS-Seq: a robust and sensitive amplification method for bead-based scRNA-seq

“…Resultant cells were resuspended with 500 μL of preparation medium. Tumor cells of the subcutaneous model of lewis lung carcinoma were collected as described previously 13 . Spleen cells were collected from the subcutaneous model of lewis lung carcinoma as described previously 13 with some modifications.…”

“…Tumor cells of the subcutaneous model of lewis lung carcinoma were collected as described previously 13 . Spleen cells were collected from the subcutaneous model of lewis lung carcinoma as described previously 13 with some modifications. Anti-CD4 antibodies (clone GK1.5, BioLegend, 200 μg/head) were intraperitoneally injected at days 5 and 9 post tumor inoculation, and the spleen was harvested at day 12 post tumor inoculation.…”

“…cDNA synthesis and Exonuclease I treatment by BD Rhapsody system. For cell hashing, CD45 + tumor-infiltrating leukocytes were stained with 2.5 μg/ml of Totalseq anti-mouse Hashtag-A antibodies (A0301-A0314, BioLegend, San Diego, CA, USA) at 4ºC for 25 minutes and washed thrice with Cell Staining Buffer (BioLegend) and pooled equally as described previously 13 . Obtained single-cell suspensions were subjected to a BD Rhapsody system with BD Rhapsody Targeted & Abseq Reagent kit (BD Biosciences) following the manufacture's instructions.…”