Biology subjects

Simonetta, F.

Publications and source records attributed to Simonetta, F..

4 recordsLinked to original sources

bioRxiv2022

Single-cell Transcriptomics Reveal Different Maturation Stages and Sublineages Commitment of Human Thymic Invariant Natural Killer T cells

Invariant natural killer T (iNKT) cells are a subset of heterogenous T-cells with potent cytotoxic and immunomodulatory properties. During thymic development, murine iNKT cells go through different maturation stages and differentiate into distinct sublineages, namely iNKT1, iNKT2, and iNKT17 cells. To define maturation stages and to assess sublineage commitment of human iNKT cells during thymic development, we performed single-cell RNA sequencing analysis on human thymic iNKT cells. We show that these iNKT cells displayed heterogeneity and unsupervised analysis identified two clusters: one with an immature profile with high expression of genes that are important for iNKT cell development and enriched in cells expressing an iNKT2 signature, whereas a second cluster displayed a mature, terminally differentiated profile resembling murine iNKT1 cells. Trajectory analysis suggested an ontological relationship between the two clusters. Our work provides the first single cell transcriptomic analysis of thymic human iNKT cells offering new insights into their developmental process in humans.

cell biology↗

bioRxiv2022

Integrated Analysis of T cell Repertoire and Transcriptome Identifies Mechanisms of Regulatory T cell (Treg) Suppression of Acute Graft-versus-Host-Disease

CD4+FOXP3+ regulatory T cells have demonstrated efficacy in graft-versus-host disease (GvHD) prevention and treatment. Preclinical and clinical studies indicate that Treg are able to protect from GvHD without interfering with the graft-versus-tumor (GvT) effect of hematopoietic cell transplantation (HCT), although the underlying molecular mechanisms are largely unknown. To elucidate Treg suppressive function during in vivo suppression of acute GvHD, we performed paired T cell receptor (TCR, TCR{beta} genes) repertoire sequencing and RNA sequencing analysis on conventional T cells (Tcon) and Treg before and after transplantation in an MHC major-mismatch mouse model of HCT. We show that both Treg and Tcon underwent clonal restriction and that Treg did not interfere with the activation of alloreactive Tcon clones and the breadth of their TCR repertoire, however, markedly suppressed their expansion. Transcriptomic analysis revealed that Treg predominantly affected the transcriptome of CD4 Tcon and to a lesser extent of CD8 Tcon, modulating the transcription of genes encoding pro- and anti-inflammatory molecules as well as enzymes involved in metabolic processes, inducing a switch from glycolysis to oxidative phosphorylation. Finally, Treg did not interfere with the induction of gene sets involved in the GvT effect. Our results shed light into the mechanisms of acute GvHD suppression by Treg and will support the clinical translation of this immunoregulatory approach. Key Points- Regulatory T cells modulate conventional T cells transcriptome during GvHD suppression by affecting several, non-redundant pathways. - Regulatory T cells undergo activation and clonal expansion during GvHD suppression.

immunology↗

bioRxiv2021

Multi-parameter optical imaging of immune cell activity in chimeric antigen receptor T-cell and checkpoint blockade therapies

Longitudinal multimodal imaging presents unique opportunities for noninvasive surveillance and prediction of treatment response to cancer immunotherapy. In this work we first designed a novel granzyme B activated self-assembly small molecule, G-SNAT, for quantitative assessment of cytotoxic T lymphocyte mediated cancer cell killing in vivo. In lymphoma tumor bearing mice, the retention of cyanine 5 labeled G-SNAT-Cy5 was shown to be highly correlated to CAR T-cell mediated granzyme B release and tumor eradication. In colorectal tumor-bearing transgenic mice, expressing firefly luciferase in hematopoietic cells, and which received combination treatment of anti-PD-1 and anti-CTLA-4, longitudinal bioluminescence and fluorescence imaging revealed the dynamics of immune cell expansion, trafficking, tumor infiltration, and cytotoxic activity which predicted therapeutic outcome before tumor shrinkage was evident. These results support further development of G-SNAT for imaging early immune response to checkpoint blockade and CAR T-cell therapy in patients and highlight the utility of multimodality imaging for improved mechanistic insights into cancer immunotherapy.

immunology↗

bioRxiv2021

Allogeneic CAR-invariant Natural Killer T Cells Exert Potent Antitumor Effects Through Host CD8 T cell Cross-Priming

The development of allogeneic chimeric antigen receptor (CAR) T cell therapies for off-the-shelf use is a major goal yet faces two main immunological challenges, namely the risk of graft-versus-host-disease (GvHD) induction by the transferred cells and the rejection by the host immune system limiting their persistence. We demonstrate that allogeneic CAR-engineered invariant natural killer T (iNKT) cells, a cell population without GvHD-induction potential that displays immunomodulatory properties, exerted potent direct and indirect antitumor activity in murine models of B-cell lymphoma when administered across major MHC-barriers. In addition to their known direct cytotoxic effect, allogeneic CAR iNKT cells induced tumor-specific antitumor immunity through host CD8 T cell cross-priming, resulting in a potent antitumor effect lasting longer than the physical persistence of the allogeneic cells. The utilization of off-the-shelf allogeneic CAR iNKT cells could meet significant unmet needs in the clinic.

immunology↗