CX3CR1-CD8+ T cells are critical in antitumor efficacy but functionally suppressed in the tumor microenvironment.

Although blockade of the programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) immune checkpoint has revolutionized cancer treatment, how it works on tumor-infiltrating CD8+ T cells recognizing the same antigen at various differentiation stages remains elusive. Here, we found that the chemokine receptor CX3CR1 identified 3 distinct differentiation states of intratumor CD8+ T cell subsets. Adoptively transferred antigen-specific CX3CR1-CD8+ T cells generated phenotypically and functionally distinct CX3CR1int and CX3CR1hi subsets in the periphery. Notably, expression of coinhibitory receptors and T cell factor 1 (Tcf1) inversely correlated with the degree of T cell differentiation defined by CX3CR1. Despite lower expression of coinhibitory receptors and potent cytolytic activity, in vivo depletion of the CX3CR1hi subset did not alter the antitumor efficacy of adoptively transferred CD8+ T cells. Furthermore, differentiated CX3CR1int and CX3CR1hi subsets were impaired in their ability to undergo proliferation upon restimulation and had no impact on established tumors upon second adoptive transfer compared with the CX3CR1- subset that remained effective. Accordingly, anti-PD-L1 therapy preferentially rescued proliferation and cytokine production of the CX3CR1- subset and enhanced antitumor efficacy of adoptively transferred CD8+ T cells. These findings provide a better understanding of the phenotypic and functional heterogeneity of tumor-infiltrating CD8+ T cells and can be exploited to develop more effective immunotherapy.

JunB regulates angiogenesis and neurovascular parallel alignment in mouse embryonic skin.

Blood vessels and nerve fibers are often closely arranged in parallel throughout the body. Therefore, neurovascular interactions have been suggested to be important for the development of vascular networks. However, the molecular mechanisms and genes regulating this process remain unclear. In the present study, we investigated the genes that are activated in endothelial cells (ECs) following interactions with neurons during vascular development. Microarray analyses of human primary microvascular ECs co-cultured with mouse primary dorsal root ganglion cells showed that JunB is strongly upregulated in ECs by neurovascular interactions. Furthermore, the forced expression of JunB in ECs stimulated a tip-like cell formation and angiogenesis in vitro and induced vascular endothelial growth factor A (VEGFA) and the pro-angiogenic integrin subunit ITGB3 expression. Moreover, in vivo knockdown of JunB in ECs from developing mouse limb skin considerably decreased the parallel alignments of blood vessels and nerve fibers. Taken together, the present data demonstrates for the first time that JunB plays an important role in the formation of embryonic vascular networks. These results contribute to the molecular understanding of neurovascular interactions during embryonic vascular development.

Generation of Induced Pluripotent Stem Cells from Human Melanoma Tumor-infiltrating Lymphocytes.

Adoptive transfer of ex vivo expanded autologous tumor-infiltrating lymphocytes (TILs) can mediate durable and complete responses in significant subsets of patients with metastatic melanoma. Major obstacles of this approach are the reduced viability of transferred T cells, caused by telomere shortening, and the limited number of TILs obtained from patients. Less-differentiated T cells with long telomeres would be an ideal T cell subset for adoptive T cell therapy;however, generating large numbers of these less-differentiated T cells is problematic. This limitation of adoptive T cell therapy can be theoretically overcome by using induced pluripotent stem cells (iPSCs) that self-renew, maintain pluripotency, have elongated telomeres, and provide an unlimited source of autologous T cells for immunotherapy. Here, we present a protocol to generate iPSCs using Sendai virus vectors for the transduction of reprogramming factors into TILs. This protocol generates fully reprogrammed, vector-free clones. These TIL-derived iPSCs might be able to generate less-differentiated patient- and tumor-specific T cells for adoptive T cell therapy.

Adoptive Transfer of CD8+ T Cells Generated from Induced Pluripotent Stem Cells Triggers Regressions of Large Tumors Along with Immunological Memory.

Current approaches to adoptive T-cell therapy are limited by the difficulty of obtaining sufficient numbers of T cells against targeted antigens with useful in vivo characteristics. Theoretically, this limitation could be overcome by using induced pluripotent stem cells (iPSC) that could provide an unlimited source of autologous T cells. However, the therapeutic efficacy of iPSC-derived regenerated T cells remains to be demonstrated. Here, we report the first successful reprogramming of T-cell receptor (TCR) transgenic CD8(+) T cells into pluripotency. As part of the work, we established a syngeneic mouse model for evaluating in vitro and in vivo antitumor reactivity of regenerated T cells from iPSCs bearing a rearranged TCR of known antigen specificity. Stably TCR retained T-cell-derived iPSCs differentiated into CD4(+)CD8(+) T cells that expressed CD3 and the desired TCR in vitro Stimulation of iPSC-derived CD4(+)CD8(+) T cells with the cognate antigen in the presence of IL7 and IL15 followed by expansion with IL2, IL7, and IL15 generated large numbers of less-differentiated CD8(+) T cells with antigen-specific potent cytokine production and cytolytic capacity. Furthermore, adoptively transferred iPSC-derived CD8(+) T cells escaped immune rejection, mediated effective regression of large tumors, improved survival, and established antigen-specific immunological memory. Our findings illustrate the translational potential of iPSCs to provide an unlimited number of phenotypically defined, functional, and expandable autologous antigen-specific T cells with the characteristics needed to enable in vivo effectiveness. Cancer Res; 76(12); 3473-83. ©2016 AACR.

Reprogramming of Melanoma Tumor-Infiltrating Lymphocytes to Induced Pluripotent Stem Cells.

Induced pluripotent stem cells (iPSCs) derived from somatic cells of patients hold great promise for autologous cell therapies. One of the possible applications of iPSCs is to use them as a cell source for producing autologous lymphocytes for cell-based therapy against cancer. Tumor-infiltrating lymphocytes (TILs) that express programmed cell death protein-1 (PD-1) are tumor-reactive T cells, and adoptive cell therapy with autologous TILs has been found to achieve durable complete response in selected patients with metastatic melanoma. Here, we describe the derivation of human iPSCs from melanoma TILs expressing high level of PD-1 by Sendai virus-mediated transduction of the four transcription factors, OCT3/4, SOX2, KLF4, and c-MYC. TIL-derived iPSCs display embryonic stem cell-like morphology, have normal karyotype, express stem cell-specific surface antigens and pluripotency-associated transcription factors, and have the capacity to differentiate in vitro and in vivo. A wide variety of T cell receptor gene rearrangement patterns in TIL-derived iPSCs confirmed the heterogeneity of T cells infiltrating melanomas. The ability to reprogram TILs containing patient-specific tumor-reactive repertoire might allow the generation of patient- and tumor-specific polyclonal T cells for cancer immunotherapy.

Regulation of soluble Flt-1 (VEGFR-1) production by hnRNP D and protein arginine methylation.

Soluble fms-like tyrosine kinase-1 (sFlt-1) functions as a potent inhibitor of angiogenesis by trapping vascular endothelial growth factor (VEGF). However, the precise regulatory mechanism of sFlt-1 production is unknown. Here, we report that vascular sFlt-1 production is regulated by heterogeneous nuclear ribonucleoprotein D (hnRNP D) and arginine methylation. We showed that hnRNP D bound to Flt-1 pre-mRNA and that hnRNP D overexpression decreased sFlt-1 mRNA in human microvascular endothelial cells (HMVECs). In contrast, the reduction of hnRNP D levels induced an increase in sFlt-1 production. Overexpression of an hnRNP D mutant in which the arginine residue of the known arginine methylation motif (arginine-glycine-glycine; RGG) was replaced with alanine did not reduce the level of soluble-form RNA produced from the Flt-1 minigene. Moreover, we demonstrated that overexpression of arginine methyltransferase decreased the soluble-form RNA level, whereas overexpression of arginine demethylase and addition of methyltransferase inhibitors increased sFlt-1 mRNA levels. These findings indicate that hnRNP D and arginine methylation play important roles in the regulation of Flt-1 mRNA alternative polyadenylation.

cAMP ameliorates inflammation by modulation of macrophage receptor for advanced glycation end-products.

Clarification of the roles of PAMPs (pathogen-associated molecular patterns) and DAMPs (damage-associated molecular patterns) is indispensable for therapeutic strategies against various inflammatory diseases. RAGE (receptor for advanced glycation end-products) is one of the PRRs (pattern recognition receptors) and has been implicated in autoimmune and inflammatory diseases. Effective remedies targeting RAGE are required for the diseases. In the present study, we show that cAMP-induced modulation of the RAGE isoform in macrophages can control the inflammatory state in both in vitro and in vivo experimental conditions. The RAGE ligand S100B stimulated MCP-1 (monocyte chemoattractant protein-1) secretion from peritoneal macrophages, but cAMP elevation suppressed it by converting the RAGE isoform from a membrane-bound into a soluble form. This shedding is the result of ectodomain cleavage of mRAGE (membrane-bound RAGE) by MMP9 (matrix metalloproteinase 9). Furthermore, forskolin significantly inhibited peritoneal macrophage accumulation in a mouse S100B-induced peritonitis model. These results suggest that cAMP serves as a negative regulator of ligand-RAGE signalling and macrophage recruitment by mRAGE down-regulation and formation of decoys as soluble receptors. The present study should deepen our understanding of the pathogenesis of RAGE-mediated tissue derangement and provide new clues for overcoming RAGE-related inflammatory diseases.

Sivelestat sodium hydrate inhibits neutrophil migration to the vessel wall and suppresses hepatic ischemia-reperfusion injury.

BACKGROUND: Sivelestat sodium hydrate (sivelestat) is a specific neutrophil elastase inhibitor that is effective in treating acute lung injury associated with systemic inflammatory response syndrome. As such, it may be useful in treating hepatic ischemia-reperfusion injury (IRI), a condition in which neutrophils transmigrate into the interstitium, leading to release of neutrophil elastase from neutrophils and consequent damage to the affected tissue, particularly in cases of hepatic failure after liver transplantation or massive liver resection. AIMS: The purpose of this study was to examine whether treatment with sivelestat inhibits neutrophil adhesion and migration to the vessel wall and suppresses hepatic IRI. METHODS: Whether and, if so, the extent to which sivelestat suppresses the adhesion and migration of neutrophils and reduces liver damage in hepatic IRI was examined in a human umbilical vein endothelial cell (HUVEC) model and a rat hepatic IRI model. RESULTS: In the HUVEC model, the extent of the adhesion and migration of neutrophils stimulated by platelet-activating factor were found to be dose-dependently inhibited by sivelestat treatment (p < 0.05). In the rat model, serum liver enzyme levels were significantly lower at 12 h after reperfusion, and the number of neutrophils that had migrated to extravascular sites was significantly less in the treatment group compared to the control group (p < 0.05). CONCLUSION: Sivelestat inhibits the adhesion and migration of neutrophils to vascular endothelium in hepatic IRI, thereby suppressing liver injury.

Low-molecular weight fractions of Japanese soy sauce act as a RAGE antagonist via inhibition of RAGE trafficking to lipid rafts.

Advanced glycation end-products (AGE) have been implicated in aging and the pathogenesis of diabetic complications, inflammation, Alzheimer's disease, and cancer. AGE engage the cell surface receptor for AGE (RAGE), which in turn elicits intracellular signaling, leading to activation of NF-κB to cause deterioration of tissue homeostasis. AGE are not only formed within our bodies but are also derived from foods, endowing them with flavor. In the present study, we assessed the agonistic/antagonistic effects of food-derived AGE on RAGE signaling in a reporter assay system and found that low-molecular weight AGE can antagonize the action of AGE-BSA. Foods tested were Japanese soy sauce, coffee, cola, and red wine, all of which showed fluorescence characteristics of AGE. Soy sauce and coffee contained N(ε)-carboxymethyl-lysine (CML). Soy sauce, coffee, and red wine inhibited the RAGE ligand-induced activation of NF-κB, whereas cola had no effect on the ligand induction of NF-κB. The liquids were then fractionated into high-molecular weight (HMW) fractions and low-molecular weight (LMW) fractions. Soy sauce-, coffee-, and red wine-derived LMW fractions consistently inhibited the RAGE ligand induction of NF-κB, whereas the HMW fractions of these foods activated RAGE signaling. Using the LMW fraction of soy sauce as a model food-derived RAGE antagonist, we performed a plate-binding assay and found that the soy sauce LMW fractions competitively inhibited AGE-RAGE association. Further, this fraction significantly reduced AGE-dependent monocyte chemoattractant protein-1 (MCP-1) secretion from murine peritoneal macrophages. The LMF from soy sauce suppressed the AGE-induced RAGE trafficking to lipid rafts. These results indicate that small components in some, if not all, foods antagonize RAGE signaling and could exhibit beneficial effects on RAGE-related diseases.

Induction of receptor for advanced glycation end products by insufficient leptin action triggers pancreatic ß-cell failure in type 2 diabetes.

Glucolipotoxicity, which is exerted by free fatty acids (FFA) and prolonged hyperglycemia, is implicated in pancreatic ß-cell failure in diabetes. Pattern recognition receptors such as receptor for advanced glycation end products (RAGE) and toll-like receptors 2 and 4 could mediate danger signals in ß-cells. We examined whether RAGE contributes to ß-cell failure in a type 2 diabetes mouse model. Pancreatic islets were isolated from ob/ob, db/db, diet-induced obesity (DIO), RAGE-null (RAGE(-/-) ), and RAGE(+/+) wild-type (WT) control mice and dispersed into single cells for flow cytometry. RAGE expression was detected in insulin-positive ß-cells of ob/ob and db/db mice, but not of WT, DIO, or RAGE(-/-) mice: thus, inadequate leptin receptor signaling and RAGE expression may be linked. Compared with RAGE(+/+) db/db mice, RAGE(-/-) db/db mice showed higher ß-cell number and mass with less apoptosis as well as glucose tolerance with higher insulin secretion without any differences in serum levels of FFA and adiponectin. Palmitate or oleate pretreatment combined with a leptin antagonist induced RAGE expression, AGE-elicited apoptosis, and impaired glucose-stimulated insulin secretion by advanced glycation end products (AGE) in MIN6 cells. FFA elevation with concomitant AGE formation during prolonged hyperglycemia could cause ß-cell damage through insufficient leptin action and subsequent RAGE induction in type 2 diabetes.

Regulation of RAGE for attenuating progression of diabetic vascular complications.

Diabetic angiopathy including micro- and macroangiopathy is concerned with high rate of morbidity and mortality in patients with long-standing diabetes. Receptor for advanced glycation end products (RAGE) and its ligands have been considered as important pathogenic triggers for the progression of the vascular injuries in diabetes. The deleterious link between RAGE and diabetic angiopathy has been demonstrated in animal studies. Preventive and therapeutic strategies focusing on RAGE and its ligand axis may be of great importance in relieving diabetic vascular complications and reducing the burden of disease.

Diabetes alters subsets of endothelial progenitor cells that reside in blood, bone marrow, and spleen.

Circulating endothelial progenitor cells (EPCs) derived from the bone marrow (BM) participate in maintaining endothelial integrity and vascular homeostasis. Reduced EPC number and function result in vascular complications in diabetes. EPCs are a population of cells existing in various differentiation stages, and their cell surface marker profiles change during the process of mobilization and maturation. Hence, a generally accepted marker combination and a standardized protocol for the quantification of EPCs remain to be established. To determine the EPC subsets that are affected by diabetes, we comprehensively analyzed 32 surface marker combinations of mouse peripheral blood (PB), BM, and spleen cells by multicolor flow cytometry. Ten subsets equivalent to previously reported mouse EPCs significantly declined in number in the PB of streptozotocin-induced diabetic mice, and this reduction was reversed by insulin treatment. The PI(-)Lin(-)c-Kit(-)Sca-1(+)Flk-1(-)CD34(-)CD31(+) EPC cluster, which can differentiate into mature endothelial cells in vitro, was the highest population in the PB, BM, and spleen and occurred 61 times more in the spleen than in the PB. The cell number significantly decreased in the BM as well as in the PB but paradoxically increased in the spleen under diabetic conditions. Insulin treatment reversed the decrease of EPC subsets in the BM and PB and reversed their increase in spleen. A similar tendency was observed in some of the major cell populations in db/db mice. To the best of our knowledge, we are the first to report spatial population changes in mouse EPCs by diabetes in the blood and in the BM across the spleen. Diminished circulating EPC supply by diabetes may be ascribed to impaired EPC production in the BM and to decreased EPC mobilization from the spleen, which may contribute to vascular dysfunction in diabetic conditions.

Septic shock is associated with receptor for advanced glycation end products ligation of LPS.

Septic shock is a severe systemic response to bacterial infection. Receptor for advanced glycation end products (RAGE) plays a role in immune reactions to recognize specific molecular patterns as pathogen recognition receptors. However, the interaction between LPS, the bioactive component of bacterial cell walls, and RAGE is unclear. In this study, we found direct LPS binding to RAGE by a surface plasmon resonance assay, a plate competition assay, and flow cytometry. LPS increased TNF-α secretion from peritoneal macrophages and an NF-κB promoter-driven luciferase activity through RAGE. Blood neutrophils and monocytes expressed RAGE, and TLR2 was counterregulated in RAGE(-/-) mice. After LPS injection, RAGE(+/+) mice showed a higher mortality, higher serum levels of IL-6, TNF-α, high mobility group box 1, and endothelin-1, and severe lung and liver pathologies compared with RAGE(-/-) mice without significant differences in plasma LPS level. Administration of soluble RAGE significantly reduced the LPS-induced cytokine release and tissue damage and improved the LPS-induced lethality even in RAGE(-/-) as well as RAGE(+/+) mice. The results thus suggest that RAGE can associate with LPS and that RAGE system can regulate inflammatory responses. Soluble RAGE would be a therapeutic tool for LPS-induced septic shock.

RAGE in diabetic nephropathy.

As is diabetes itself, diabetic angiopathy is a multi-factorial disease. Advanced glycation endproducts (AGE) cause vascular cell derangement characteristic of diabetes, and this is mainly mediated by their interaction with receptor for AGE (RAGE). When made diabetic, RAGE-overexpressing transgenic mice exhibited exacerbation of the indices of nephropathy, and this was prevented by the inhibition of AGE formation. On the other hand, RAGE-deficient animals showed amelioration of diabetic nephropathy. Accordingly, AGE and RAGE should be regarded as environmental and cellular accounts and as a potential therapeutic target for diabetic nephropathy. In effect, substances that inhibit the formation of AGE, break preformed AGE, change metabolic flows away from glycation, antagonize RAGE, and capture RAGE ligands have been proven as effective remedies against this life-threatening disease.