Project description:The tumor microenvironment (TME) contains various immune-suppressive cells such as T helper 1-polarized regulatory T cells (Th1-Tregs). However, little is known about the mechanism behind the abundant presence of Th1-Tregs in TME. In this work, we demonstrate that selective depletion of arginase I (Arg1)-expressing tumor associated macrophages (Arg1+ TAMs) inhibits tumor growth and concurrently reduces the Th1-Treg ratio in TME. Notably, Arg1+ TAMs secrete platelet factor 4 (PF4) that reinforces interferon-γ (IFN-γ)-induced Treg polarization into Th1-Tregs in a manner dependent on CXCR3 and the IFN-γ receptor. Both genetic PF4 inactivation and PF4 neutralization hinder Th1-Treg accumulation in TME, consequently suppressing tumor growth. Collectively, our study highlights the importance of Arg1+ TAM-produced PF4 for high Th1-Treg levels in TME to suppress anti-tumor immunity, and demonstrates PF4 neutralization as a potential cancer immunotherapeutic strategy.
Project description:The tumor microenvironment (TME) contains various immune-suppressive cells such as regulatory T cells (Tregs) and M2-like tumor associated macrophages (TAMs) that express the enzyme arginase I (Arg1). T helper 1-polarized Treg (Th1-Treg) is a Treg subset that markedly accumulate in tumor tissues, suppressing anti-tumor immunity. However, little is known about the mechanism behind the abundant presence of Th1-Tregs in TME. Here we show that Arg1-expressing TAMs (Arg1+ TAMs) play critical roles for the high Th1-Treg ratio in TME. Selective depletion of Arg1+ TAMs using the VeDTR system inhibited tumor growth and concurrently reduced the Th1-Treg ratio in TME. Notably, Arg1+ TAMs secreted platelet factor 4 (PF4) that polarized Tregs to Th1-Tregs in a CXCR3-dependent manner. Both genetic PF4 inactivation and PF4 neutralization hindered Th1-Treg accumulation in TME, consequently suppressing tumor growth. Collectively, our study highlights the importance of M2-like TAM-produced PF4 for high Th1-Treg levels in TME to suppress anti-tumor immunity, and demonstrates PF4 neutralization as a potential cancer immunotherapeutic strategy by intervening the M2-like TAM/Th1-Treg axis.
Project description:This study provides evidence on the molecular mechanisms by which P2RX7 signaling promotes Th1 cell differentiation. P2RX7 induces T-bet expression and aerobic glycolysis in splenic CD4+ T cells that respond to malaria, at a time prior to Th1/Tfh polarization. Cell-intrinsic P2RX7 signaling sustains the glycolytic pathway and causes bioenergetic mitochondrial stress in activated CD4+ T cells. We also show in vitro the phenotypic similarities of Th1-polarized CD4+ T cells that do not express P2RX7 and those in which the glycolytic pathway is pharmacologically inhibited. In addition, ATP synthase blockade in vitro and the consequent inhibition of oxidative phosphorylation, which forces cells to use aerobic glycolysis, is sufficient to promote rapid CD4+ T cell proliferation and polarization to the Th1 profile in the absence of P2RX7. These data demonstrate that P2RX7-mediated metabolic reprograming for aerobic glycolysis is a key event for Th1 cell differentiation and suggest that ATP synthase inhibition is a fundamental mechanism by which P2X7 signaling induces the Th1 response.
Project description:Gastrointestinal nematode (GIN) is a major economic and health concern is sheep farming. Sheep breeds such as Texel are relatively resistant to GIN than the Suffolk. With the objective to understand the underlying genetic mechanism of resistance and susceptibility at the transcriptomic level, two groups of animal from both the breed were artificially (orally) infected with 30,000 L3 larvae of prominent GIN Teladorsagia circumcincta. Subgroups of animals from each breed were slaughtered on day 0, 3, 7, 14 and 21 of post infection (p.i.). Transcriptomic profiling of abomasal lymph node was performed using RNA-seq. The perturbations in gene expression profiles in both the breeds were evident and Texel showed a more tightly regulated immune response than the Suffolk. The number of differentially expressed (DE) genes between the breeds was highest (437) on un-infected control (day 0) and lowest (173) on day 7 p.i.. Pathway analysis of DE genes identified 3 significant pathways, which involved only more highly expressed genes of Suffolk breed on day 0 and only more highly expressed genes of Texel (with one exception) on day 7 p.i.. The Th1, Th2 and Treg response was evident in response to GIN in Texel and was synchronized, while in Suffolk Th1 response was reduced after infection and pronounced Th2 and Treg was not evident. The study suggests maximum level of transcriptional activity in both breeds on day 7 p.i. and there was a shift of transcriptional activity from Suffolk on day 0 to Texel on day 7 p.i.. Suffolk had a reduced Th1 response with less pronounced Th2 and Treg immune response, while Texel had an active and synchronized Th1/Th2/Treg immune response in response to GIN infection. Abomasal lymph node tissue was taken from control (n=10) and experimentally infected (with T. circumcincta) lambs (n=36) from Texel and Suffolk breed on day 0, 3, 7, 14 and 21 post infection.
Project description:CD4+Foxp3+ Treg cells are essential for maintaining self-tolerance and preventing excessive immune responses. In the context of Th1 immune responses, co-expression of the Th1 transcription factor T-bet with Foxp3 is essential for Treg cells to control Th1 responses. T-bet-dependent expression of CXCR3 directs Tregs to the site of inflammation, however, the suppressive mediators enabling effective control of Th1 responses at this site are unknown. In this study, we determined the signature of CXCR3+ Treg cells arising in Th1 settings and defined universal features of Treg cells in this context using multiple Th1-dominated models. Our analysis defined a set of Th1-specific co-inhibitory receptors that are specifically expressed in Treg cells during Th1 immune responses. Among these, we identified the novel co-inhibitory receptor CD85k as a functional mediator of the enhanced suppression of Th1 effector cells by CXCR3+ Treg cells.
Project description:The immune system comprises various cell types including regulatory T (Treg) cells, and their subsets. Since most of inducible depletion of immune cells for the functional analysis rely on a single protein or gene, it is no longer optimal for the analysis of cell subsets defined by multiple genes. Here we create the Cre- and Flp-double recombinase-dependent intersectional genetic VeDTR mouse system that can selectively label and inducibly deplete a subpopulation of Treg cells called T helper 1 (Th1)-Treg cells. Characterization of Th1-Treg cells using the VeDTR mice revealed the high resistance under oxidative stress, which was required for Th1-Treg cells to accumulate in tumor tissues. Moreover, short-term depletion of Th1-Treg cells only led to anti-tumor immunity but not autoimmunity, whereas that of whole Treg cells did both. Collectively, we have established a novel intersectional genetic immune cell depletion system to reveal unique features of Th1-Treg cells in tumor immunity.
Project description:Regulatory T cells (Treg) are conventionally viewed to suppress endogenous and therapy-induced anti-tumor immunity; however, their role in modulating responses to immune checkpoint blockade (ICB) is unclear. In this study, we integrated single-cell RNAseq/TCRseq of >73,000 tumor-infiltrating Treg (TIL-Treg) from anti-PD-1-treated and treatment naive non-small cell lung cancers (NSCLC) with single cell analysis of tumor-associated antigen (TAA)-specific Treg derived from a murine tumor model. We identified 10 subsets of human TIL-Treg, most of which have high concordance with murine TIL-Treg subsets. Notably, only one subset selectively expresses high levels of OX40 and GITR, whose engangement by cognate ligand mediated proliferative programs and NF-kB activation, as well as multiple genes involved in Treg suppression, including LAG3. Functionally, the OX40hiGITRhi subset is the most highly suppressive ex vivo and its higher representation among total TIL-Treg correlated with resistance to PD-1 blockade. Surprisingly, in the murine tumor model, we found that virtually all TIL-Treg expressing T cell receptors that are specific for TAA fully develop a distinct Th1-like signature over a two-week period after entry into the tumor, down-regulating FoxP3 and up-regulating expression of TBX21 (Tbet), IFN and certain pro-inflammatory granzymes. Transfer learning of a gene score from the murine TAA-specific Th1-like Treg subset to the human single-cell dataset revealed a highly analogous subcluster that was enriched in anti-PD-1 responding tumors. These findings demonstrate that TIL-Treg partition into multiple distinct transcriptionally-defined subsets with potentially opposing effects on ICB-induced anti-tumor immunity and suggest that TAA-specific TIL-Treg may positively contribute to anti-tumor responses.
Project description:Regulatory T cells (Treg) are conventionally viewed to suppress endogenous and therapy-induced anti-tumor immunity; however, their role in modulating responses to immune checkpoint blockade (ICB) is unclear. In this study, we integrated single-cell RNAseq/TCRseq of >73,000 tumor-infiltrating Treg (TIL-Treg) from anti-PD-1-treated and treatment naive non-small cell lung cancers (NSCLC) with single cell analysis of tumor-associated antigen (TAA)-specific Treg derived from a murine tumor model. We identified 10 subsets of human TIL-Treg, most of which have high concordance with murine TIL-Treg subsets. Notably, only one subset selectively expresses high levels of OX40 and GITR, whose engangement by cognate ligand mediated proliferative programs and NF-kB activation, as well as multiple genes involved in Treg suppression, including LAG3. Functionally, the OX40hiGITRhi subset is the most highly suppressive ex vivo and its higher representation among total TIL-Treg correlated with resistance to PD-1 blockade. Surprisingly, in the murine tumor model, we found that virtually all TIL-Treg expressing T cell receptors that are specific for TAA fully develop a distinct Th1-like signature over a two-week period after entry into the tumor, down-regulating FoxP3 and up-regulating expression of TBX21 (Tbet), IFN and certain pro-inflammatory granzymes. Transfer learning of a gene score from the murine TAA-specific Th1-like Treg subset to the human single-cell dataset revealed a highly analogous subcluster that was enriched in anti-PD-1 responding tumors. These findings demonstrate that TIL-Treg partition into multiple distinct transcriptionally-defined subsets with potentially opposing effects on ICB-induced anti-tumor immunity and suggest that TAA-specific TIL-Treg may positively contribute to anti-tumor responses.
Project description:Gastrointestinal nematode (GIN) is a major economic and health concern is sheep farming. Sheep breeds such as Texel are relatively resistant to GIN than the Suffolk. With the objective to understand the underlying genetic mechanism of resistance and susceptibility at the transcriptomic level, two groups of animal from both the breed were artificially (orally) infected with 30,000 L3 larvae of prominent GIN Teladorsagia circumcincta. Subgroups of animals from each breed were slaughtered on day 0, 3, 7, 14 and 21 of post infection (p.i.). Transcriptomic profiling of abomasal lymph node was performed using RNA-seq. The perturbations in gene expression profiles in both the breeds were evident and Texel showed a more tightly regulated immune response than the Suffolk. The number of differentially expressed (DE) genes between the breeds was highest (437) on un-infected control (day 0) and lowest (173) on day 7 p.i.. Pathway analysis of DE genes identified 3 significant pathways, which involved only more highly expressed genes of Suffolk breed on day 0 and only more highly expressed genes of Texel (with one exception) on day 7 p.i.. The Th1, Th2 and Treg response was evident in response to GIN in Texel and was synchronized, while in Suffolk Th1 response was reduced after infection and pronounced Th2 and Treg was not evident. The study suggests maximum level of transcriptional activity in both breeds on day 7 p.i. and there was a shift of transcriptional activity from Suffolk on day 0 to Texel on day 7 p.i.. Suffolk had a reduced Th1 response with less pronounced Th2 and Treg immune response, while Texel had an active and synchronized Th1/Th2/Treg immune response in response to GIN infection.