Upregulation Of CD36 Research Articles

Combined Epigenetic and Immunotherapy For Newly Diagnosed Mantle Cell Lymphoma: Correlative Studies Suggest The Importance Of Enhanced ADCC, Mechanisms of Resistance and Cyclin D1 Nuclear Localization Genotype

Previously, we reported that epigenetic therapy with cladribine, SAHA, and rituximab (SCR) for newly diagnosed mantle cell lymphoma was remarkably effective, with 100% overall response rate, 85-90% CR rate, and durable responses( Hasanali, AACR,2013 LBA140). Over 40 patients now have been enrolled with all patients completing therapy. Final response and CR rates will be reported at the meeting. This abstract will focus on the correlative studies performed as part of this trial.Cladribine, a purine analog with reported epigenetic activity was shown here by HELP assays to inhibit DNA methylation in vivo in 6 patients with leukemic MCL. Similar activity was also observed in two MCL and two CLL patients treated with cladribine without vorinostat off trial, suggesting cladribine is a DNA hypomethylating agent. Due to cladribine's ability to inhibit the enzyme SAH hydrolase and thus inhibit the donation of methyl groups by S-adenosyl methionine (SAM), we assayed the ability of cladibine to inhibit histone methylation in vitro by Western blot analysis and in vitro assays of histone methyltransferase (HMT) activity on H3lys9 and H3lys27. Both assays demonstrated inhibition of methylated histones (Western) and HMT activity using MCL cell cells and nuclear extract at concentrations of cladribine in the 10-20 um range, higher than the in vivo concentration of 10-20 nm. These observations could be due to the lack of sensitivity of these assays, and more sensitive assays are in development.Studies to help elucidate the mechanism of action of synergy of epigenetic drugs with the monoclonal antibody rituximab were performed. Using cells from patients with leukemic MCL treated with SCR, we assayed for characteristic changes of apoptosis using Western blotting and TUNEL assays. None were detected. We were unable to observe complement mediated cytoxicity in vitro using human serum and rituximab with added cladribine or vorinostat. With ADCC being the primary mechanism of presumed combined epigenetic and rituximab synergy, we investigated ADCC further. CD137 transcriptional upregulation was seen in several but not all treated patients, and some patients showed up regulation of perforin and granzyme mRNA by QRTPCR. An NK cell line, NKL, showed transcriptional upregulation of CD137 after treatment with cladribine and vorinostat.A polymorphism at an intron-exon junction effects the nuclear localization of cyclin D1 by removing a nuclear export signal. Although there is published evidence supporting the role of nuclear cyclin D1 in increased oncogenesis, the role of this polymorphism in MCL remains controversial. Samples from peripheral blood of patients on trial were genotyped at the cyclin D1 locus as AA, AG, or GG, with the A allele being the loss of function allele. The presence of the A allele strongly correlated with the blastic phenotype and the lack of complete remission after SCR therapy, with both being statistically significant (table 1). Immunofluorescent studies with cyclin D1 antibodies showed nuclear and cytoplasmic localization as predicted in patients with the AA and GG genotypes (Fig 1). The heterozygotes are under investigation and will be reported. [Display omitted] [Display omitted] The mechanism of resistance to SCR was studied in a patient with blastic, leukemic MCL. A 63 male achieved complete remission after two cycles of SCR. Subsequently, he developed neurologic symptoms and was found to have CNS disease. At autopsy, CD20+ disease was found in his CNS and CD20- disease was found systemically. A cell line was established from his peripheral blood that showed significantly reduced levels of CD20 mRNA. Treatment of these cells with a variety of epigenetic drugs was unable to upregulate CD20 mRNA. These cells have been in continuous culture for over 1 year and continue to show diminished levels of CD20 mRNA and protein. Epigenetic changes at the promoter are being studied by chromatin immunoprecipation (ChiP) assays. Disclosures:No relevant conflicts of interest to declare.

Transdifferentiation Of Primary Human Philadelphia Chromosome-Positive B Cell Acute Lymphoblastic Leukemia Cells Into Non-Leukemic Macrophages

Abstract Background Despite the addition of tyrosine kinase inhibitors to treatment regimens for Philadelphia chromosome-positive (Ph+) precursor B cell acute lymphoblastic leukemia (B-ALL), the prognosis for adults with this disease remains poor, highlighting the need for better treatments. Ph+ B-ALL is characterized by frequent deletions in transcription factors required for normal B cell development. While these mutations are not obviously “druggable” by conventional means, these findings indicate that B cell maturation arrest is crucial to disease pathogenesis. This suggests that strategies to induce differentiation of B-ALL blasts might provide a novel avenue for therapy, but, to date, no such therapies have been developed. Previous studies have demonstrated that normal B cell progenitors retain the potential to transdifferentiate into cells of the myeloid lineage, and we hypothesized that B-ALL cells might possess this latent myeloid potential as well. Methods and Results To investigate the transdifferentiation potential of B-ALL cells, we FACS-purified B-ALL blasts from 12 patients with Ph+ disease and exposed them to myeloid differentiation-promoting cytokines in vitro for 12 days. In 6 of 12 cases, culturing leukemic blasts under these conditions led to their transdifferentiation into cells that morphologically resembled normal human macrophages. These cells expressed typical monocyte/macrophage markers including CD14, CD11b, and CD11c and downregulated the B cell marker CD19. In addition, the transdifferentiated cells were able to perform phagocytosis and generate an oxidative burst, functions that are typical of macrophages. Using gene expression profiling and gene set enrichment analysis (GSEA), we found that the transdifferentiated B-ALL blasts possess a gene expression profile that most closely resembles macrophage/monocyte gene expression signatures. Furthermore, using fluorescence in situ hybridization for BCR-ABL and immunoglobulin heavy chain clonality assays, we demonstrated that these macrophages were clonally related to the B-ALL blasts initially isolated from the patients. The CCAAT/enhancer-binding protein alpha (CEBPα) has been shown to induce transdifferentiation of normal precursor B cells to the macrophage linage, and we sought to determine whether this effect would be seen in primary B-ALL blasts as well. Similar to the effect seen using myeloid cytokines, we found that ectopic expression of CEBPα in B-ALL blasts led to upregulation of CD14 and downregulation of CD19 in these primary human B-ALL cells. To determine if transdifferentiation impairs leukemogenicity, we transplanted macrophages derived from primary B-ALL samples into immunodeficient NOD/SCID/IL2R-gamma null (NSG) mice. The transdifferentiated cells failed to engraft whereas primary Ph+ B-ALL blasts showed robust engraftment, demonstrating a detrimental effect of myeloid transdifferentiation on leukemogenicity. B-ALL blasts that remained CD19hi/CD14lo after culture were still capable of engrafting NSG mice and causing disease, indicating that ex vivo culturing alone did not eliminate leukemogenicity. Conclusions Here, we demonstrate that primary Ph+ B-ALL blasts can transdifferentiate to the myeloid lineage by either exposure to myeloid differentiation-promoting cytokines or ectopic expression of CEBPα. The resulting cells resemble normal human macrophages in morphology, immunophenotype, gene expression, and function. Most importantly, we show that transdifferentiated B-ALL blasts failed to engraft immunocompromised mice and cause leukemia. Our findings suggest that the induction of transdifferentiation represents a novel therapeutic strategy for the treatment of Ph+ B-ALL. Disclosures: No relevant conflicts of interest to declare.

Human casein alpha s1 (CSN1S1) skews in vitro differentiation of monocytes towards macrophages

BackgroundThe milk-derived protein human Casein alpha s1 (CSN1S1) has recently been detected in blood cells and was shown to possess proinflammatory properties. In the present study, we investigated the effect of CSN1S1 on the differentiation of monocytes.MethodsPrimary human monocytes were stimulated with recombinant CSN1S1 and compared to cells stimulated with GM-CSF/IL-4 or M-CSF/IFNγ. Morphological changes were assessed by microscopy and quantification of surface markers of differentiation by FACS analysis. Phagocytic activity of CSN1S1 stimulated cells was measured by quantification of zymosan labeled particle uptake. The role of mitogen activated protein kinases for CSN1S1-induced differentiation of monocytes and proinflammatory cytokine expression was assessed by supplementation of specific inhibitors.ResultsCSN1S1 at a concentration of 10 μg/ml resulted in morphological changes (irregular shape, pseudopodia) and aggregation of cells, comparable to changes observed in M-CSF/IFNγ differentiated macrophages. Surface marker expression was altered after 24 h with an upregulation of CD14 (mean 2.5 fold) and CD64 (1.9 fold) in CSN1S1 stimulated cells. CSN1S1 treated cells showed a characteristic surface marker pattern for macrophages after 120 h of incubation (CD14high, CD64high, CD83low, CD1alow) comparable to changes observed in M-CSF/IFNγ treated monocytes. Furthermore, phagocytic activity was increased 1.4 and 1.9 fold following stimulation with 10 μg/ml CSN1S1 after 24 and 48 h, respectively. Early GM-CSF, but not GM-CSF/IL-4 induced differentiation of monocytes towards dendritic cells (DC) was inhibited by addition of CSN1S1. Finally, CSN1S1 induced upregulation of CD14 was impeded by inhibition of ERK1/2, while inhibition of the mitogen activated protein kinases JNK and p38 did not influence cellular differentiation. However, JNK and p38 inhibitors impeded CSN1S1 induced secretion of the proinflammatory cytokines IL-1b or IL-6.ConclusionsCSN1S1 skews in vitro differentiation of monocytes towards a macrophage-like phenotype. Data is accumulating that functions of CSN1S1 are beyond nutritional properties and include immunomodulatory effects.

Reg3β Deficiency Impairs Pancreatic Tumor Growth by Skewing Macrophage Polarization

The lectin Reg3β provides crucial protection to various tissues against inflammation, a potential risk factor for pancreatic ductal adenocarcinoma. Reg3β is also overexpressed in serum and pancreatic juice from patients with this cancer, but its function in this context remains to be elucidated. In this study, we investigated the role of Reg3β in tumor development in an orthotopic mouse model of pancreatic cancer. Reg3β deletion in mice drastically impaired pancreatic tumor growth, correlating with decreased angiogenesis and increased apoptosis of tumor cells. Moreover, Reg3β deficiency resulted in an alteration of the tumoral immune microenvironment, reflected by a decrease in the M2/M1 ratio of tumor-associated macrophages and an upregulation of CD3(+) cell infiltration. Addition of Reg3β to prestimulated RAW 264.7 or primary macrophages enhanced M2 polarization through the activation of STAT3 signaling pathway. Conditioned media from Reg3β-M2-polarized primary macrophages inhibited apoptosis and prolonged the viability of Panc02 tumor cells. Our studies reveal a novel role for Reg3β as a tumor promoter in pancreatic adenocarcinoma through the regulation of tumor stroma. Thus, inhibition of this protein may be a useful strategy in treatment of pancreatic cancer.

Phenotype and Function of T Cells Infiltrating Visceral Metastases from Gastrointestinal Cancers and Melanoma: Implications for Adoptive Cell Transfer Therapy

Adoptive cell transfer of tumor-infiltrating lymphocytes (TILs) can mediate cancer regression in patients with metastatic melanoma, but whether this approach can be applied to common epithelial malignancies remains unclear. In this study, we compared the phenotype and function of TILs derived from liver and lung metastases from patients with gastrointestinal (GI) cancers (n = 14) or melanoma (n = 42). Fewer CD3(+) T cells were found to infiltrate GI compared with melanoma metastases, but the proportions of CD8(+) cells, T cell differentiation stage, and expression of costimulatory molecules were similar for both tumor types. Clinical-scale expansion up to ~50 × 10(9) T cells on average was obtained for all patients with GI cancer and melanoma. From GI tumors, however, TIL outgrowth in high-dose IL-2 yielded 22 ± 1.4% CD3(+)CD8(+) cells compared with 63 ± 2.4% from melanoma (p < 0.001). IFN-γ ELISA demonstrated MHC class I-mediated reactivity of TIL against autologous tumor in 5 of 7 GI cancer patients tested (9% of 188 distinct TIL cultures) and in 9 of 10 melanoma patients (43% of 246 distinct TIL cultures). In these assays, MHC class I-mediated up-regulation of CD137 (4-1BB) expression on CD8(+) cells suggested that 0-3% of TILs expanded from GI cancer metastases were tumor-reactive. This study implies that the main challenge to the development of TIL adoptive cell transfer for metastatic GI cancers may not be the in vitro expansion of bulk TILs, but the ability to select and enrich for tumor-reactive T cells.

GW24-e0756 Nicotine exacerbates atherosclerosis by upregulation and activation of CD36 in macrophage

ObjectivesCD36, a class B scavenger receptor expressed on macrophages mediates uptake of oxLDL and contributes to foam cell formation, a hallmark of early atherosclerosis. Tobacco smoking is a major risk...

Porphyromonas gingivalis lipopolysaccharide increases lipid accumulation by affecting CD36 and ATP-binding cassette transporter A1 in macrophages

Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS) promotes macrophage-derived foam cell formation, however, the mechanisms are not well established. In macrophages, lipid uptake is mediated by scavenger receptors including SR-A and CD36, while the cholesterol efflux is mediated by ATP-binding cassette transporter G1 (ABCG1), ABCA1 and SR-BI. We further investigated the mechanisms underlying the dysregulation by P. gingivalis LPS of these regulators resulting in the promotion of lipid accumulation in THP-1-derived macrophages. Our results showed that P. gingivalis LPS exacerbated lipid accumulation in oxidized low-density lipoprotein (oxLDL)-treated macrophages. However, cholesterol efflux was inhibited by P. gingivalis LPS in THP-1-derived macrophages. In oxLDL-untreated macrophages, P. gingivalis LPS treatment caused an increase in CD36 mRNA and protein levels, and a decrease in ABCA1 mRNA and protein levels, while having no effect on SR-A, SR-BI or ABCG1 expression. Upregulation of CD36 by P. gingivalis LPS resulted from activation of c-Jun/AP-1, and this was confirmed by the inhibition of increased CD36 expression after AP-1 inhibition using SP600125. However, the decreased protein stability of ABCA1 by P. gingivalis LPS was a result of increased calpain activity. Moreover, small hairpin RNA (shRNA) targeting heme oxygenase-1 (HO-1) augmented the P. gingivalis LPS-induced atherogenic effects on the expression of c-Jun/AP-1, CD36, ABCA1 and calpain activity. Accordingly, P. gingivalis LPS-regulated promotion of lipid accumulation in foam cells was also exacerbated by HO-1 shRNA. These results indicate that P. gingivalis LPS confers a exacerbation effect on the formation of foam cells by a novel HO-1-dependent mediation of cholesterol efflux and lipid accumulation in macrophages.

Tumor-Specific T Cells in Human Merkel Cell Carcinomas: A Possible Role for Tregs and T-Cell Exhaustion in Reducing T-Cell Responses

Merkel cell carcinomas (MCC) are rare but highly malignant skin cancers associated with a novel polyomavirus. MCC tumors were infiltrated by T cells, including effector, central memory and regulatory T cells. Infiltrating T cells showed markedly reduced activation as evidenced by reduced expression of CD69 and CD25. Treatment of MCC tumors in vitro with IL-2 and IL-15 led to T cell activation, proliferation, enhanced cytokine production and loss of viable tumor cells from cultures. Expanded tumor-infiltrating lymphocytes showed TCR repertoire skewing and upregulation of CD137. MCC tumors implanted into immunodeficient mice failed to grow unless human T cells in the tumor grafts were depleted with denileukin diftitox, suggesting tumor-specific T cells capable of controlling tumor growth were present in MCC. Both CD4+ and CD8+ FOXP3+ regulatory T cells were frequent in MCC. 50% of non-activated T cells in MCC expressed PD-1, a marker of T-cell exhaustion, and PD-L1 and PD-L2 were expressed by a subset of tumor dendritic cells and macrophages. In summary, we observed tumor-specific T cells with suppressed activity in MCC tumors. Agents that stimulate T cell activity, block Treg function or inhibit PD-1 signaling may be effective in the treatment of this highly malignant skin cancer.

Up-regulation of alternate co-stimulatory molecules on proinflammatory CD28null T cells in bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is associated with lack of immunosuppression of T cell proinflammatory cytokines and increased T cell granzyme B. Repeated antigen-driven proliferation down-regulates T cell CD28. We hypothesized that down-regulation of CD28 and up-regulation of alternate co-stimulatory molecules (CD134, CD137, CD152 and CD154) on T cells may be associated with BOS. Co-stimulatory molecules, granzyme B, perforin and intracellular cytokines were measured by flow cytometry on T cells from stable lung transplant patients (n = 38), patients with BOS (n = 20) and healthy controls (n = 10). There was a significant increase in the percentage of CD4/28(null) and CD8/28(null) T cells producing granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α in BOS compared with stable patients. Down-regulation of CD28 was associated with steroid resistance and up-regulation of CD134, CD137, CD152 and CD154 on CD4(+) T cells and CD137 and CD152 on CD8(+) T cells. There was a significant correlation between increased CD28(null) /CD137 T cells producing IFN-γ, TNF-α with BOS grade (r = 0·861, P < 0·001 for CD28(null) /CD137 IFN-γ/CD8) and time post-transplant (r = 0·698, P < 0·001 for CD28(null) /CD137 IFN-γ/CD8). BOS is associated with down-regulation of CD28 and up-regulation of alternate co-stimulatory molecules on steroid-resistant peripheral blood proinflammatory CD4(+) and CD8(+) T cells. Therapeutic targeting of alternate co-stimulatory molecules on peripheral blood CD28(null) T cells and monitoring response using these assays may help in the management of patients with BOS.

A phase Ib, open-label, multicenter study of urelumab (BMS-663513) in combination with rituximab in subjects with relapsed/refractory B-cell malignancies.

TPS3108 Background: CD137 (4-1BB) is a costimulatory molecule that belongs to the TNF superfamily. It is upregulated on activated lymphocytes, NK cells and dendritic cells and plays an important role in the potentiation of antigen-specific immune responses as well as in antibody-dependent cell-mediated cytotoxicity (ADCC). Urelumab is an agonistic antibody targeting the CD137 receptor. Preclinical evidence has shown that there is modulation of CD137 expression on NK cells after exposure to rituximab. Anti-CD137 agonist monoclonal antibody has been shown to have single-agent anti-lymphoma activity and to potentiate the anti-lymphoma activity of rituximab through enhancing ADCC. We hypothesized that upregulation of CD137 on NK cells by rituximab followed by urelumab could afford a mechanism-based approach to achieve enhanced biologic and/or clinical activity compared to either single agent alone. Here we describe a phase Ib study to investigate the clinical and biologic effects of combined treatment with urelumab and rituximab in patients with relapsed/refractory B-cell malignancies. Methods: This phase I study (n=100) will include dose escalation (Part 1) using a 3+3+3 design and cohort expansion (Part 2). In Part 1, successive cohorts of patients with relapsed/refractory B-NHL will be treated as follows: Cohort 1 (0.1 mg/kg q3weeks) and Cohort 2 (0.3 mg/kg q3weeks) with both cohorts in combination with rituximab 375 mg/m2 given weekly for the first 4 weeks of each 12 week cycle. In Part 2, cohorts of CLL (n=30), follicular lymphoma (FL) (n=30), and diffuse large B-cell lymphoma (DLBCL) (n=20) will be treated at the dose level found to be safe for the urelumab/rituximab combination. The primary objective of the study is to evaluate the safety and define a safe and effective dose of the urelumab/rituximab combination. Secondary objectives include assessment of the antitumor activity, pharmacokinetics, and immunogenicity. Exploratory objectives include investigation of the immunoregulatory activity of this combination in peripheral blood and paired tumor biopsy specimens and the association of these effects with clinical response/toxicity. Clinical trial information: NCT01775631.

Immunomodulatory effects of a dipeptidyl peptidase inhibitor, ARI-4175, and NK cell activation in a colon cancer model.

3058 Background: A possible mechanism of the antitumor effect of therapeutic antibodies is antibody-dependent cellular cytotoxicity (ADCC). We reported that an inhibitor of dipeptidyl peptidase (DPP)4-like serine proteases, Ari-4175, significantly slowed the growth of KRAS-mutated HCT-116 xenografts in nude mice, either as a single agent or with cetuximab (Ctx). Ari-4175 is not cytotoxic in vitro, and since it was able to overcome the resistance to Ctx due to the KRAS mutation in the HCT-116 line, we hypothesized that the antitumor activity involves the activation of NK cells and enhancement of ADCC. Methods: Ari-4175 was administered orally to nude mice at 200 µg q.d. x5 days/week. Peripheral blood or spleens were assayed for immune parameters, ex vivo, at various time points. Expression of surface markers on myeloid and NK cells were monitored by flow. Natural cytotoxicity and ADCC were assayed using HCT116 cells and Ctx using a flow based assay. Cytokines were measured using Luminex assays. Results: Ari-4175 induced upregulation of CD69 on NK cells on day 2, followed by upregulation of CD16 on day 7. Coordinate with these changes in peripheral blood, splenocytes from treated mice exhibited significantly increased in vitro cytotoxicity toward the HCT116 cells. Increased serum levels of inflammatory cytokines, including IL-1b, IL-6, MCP-1, GCSF, and IL-2 were seen. A significant expansion of a distinct CD45+CD14+Gr-1+MHC-II-CDllb+CD11cvariable myeloid cell population in both peripheral blood and spleens of mice was also seen after one week of treatment. Conclusions: Ari-4175 showed dramatic anti-tumor effect in KRAS-mutant CRC xengrafts when given alone or in combination with Ctx. In vitro data suggest that the therapeutic effect of 4175 might partially be due to the augmentation of ADCC through elevated expression of CD16 on NK cells. In addition, Ari-4175 appears, in vivo, to expand a unique myeloid cell population, which may be responsible for an inflammatory cytokine response and subsequent activation of NK cells. Our study provides a mechanistic rationale for testing Ari-4175 in a clinical trial and possible biomarker endpoints for evaluation in peripheral blood samples.

Abstract 363: Proatherogenic and Proinflammatory Effects of Angiotensin II are Mediated by Activation of HIF-CD36 Pathway in Macrophages

Recent studies have demonstrated that the renin angiotensin system (RAS) has profound effects on atherosclerosis, but the mechanisms underlying remain unclear. Macrophages play a central role in atherogenesis through scavenger receptor-mediated lipid accumulation, production of inflammatory cytokines and transformation of macrophages into foam cells. Macrophages express all components of RAS. Here we investigated the effects of Ang II on macrophage activation and foam cell formation, and underlying the mechanisms involved. In human THP1 macrophages, Ang II (100 nM) in time-dependent manner increased the mRNA expression of proinflammatory cytokines MCP1, TNFa, IL1b, IL6, CXCL9 and PAI1, Ang II also upregulated mRNA expression of CD36, TLR4 and hypoxia induced factor (HIF)1a. Knockdown of HIF1a by SiRNA prevented Ang II upregulation of CD36 and TLR4 expression, and significantly reduced the Ang II-induced proinflammatory cytokine expression. Next, we investigated the effects of Ang II on oxLDL uptake and foam cell formation, Ang II increased oxLDL uptake, which was prevented by either siRNA HIF1a or siRNA CD36. The incubation with oxLDL (50 ug/ml) for 72 hours result in lipid deposition in macrophage or foam cell formation, preincubation with Ang II further increased oxLDL-induced lipid deposition and foam cell formation, which was also prevented by either siRNA HIF1a or siRNA CD36. Infusion of Ang II into Apo E-/- mice significantly increased systolic blood pressure, the peripheral blood CD11b+/LyC6Hi inflammatory monocyte population and mRNA expression of IL1b and TNF1a in the peritoneal macrophages, Ang II also significantly increased atherosclerotic lesion formation. Hydrolazine normalized SBP but did not significantly reduce CD11b+/LyC6hi inflammatory monocyte population and atherosclerotic lesion formation in the apo E-/- mice treated with Ang II. The present study demonstrates, for the first time, that Ang II activates HIFa-CD36 pathway in human macrophage, which potentiate atherogenic lipid-induced macrophage activation and foam cell formation. Our novel findings may elucidate new mechanisms by which Ang II promotes atherogenesis through mediating macrophage activation and lipid metabolism.

Antibacterial Capacity of Differentiated Murine Embryonic Stem Cells During Defined In Vitro Inflammatory Conditions

Embryonic stem (ES) cells are a powerful model for the development of cells responsible for the cellular immune response. Therefore, we analyzed the defense and phagocytic capacity of embryoid bodies (EBs) derived from ES cells using in the vitro inflammatory conditions caused by Escherichia coli. Further, we used this phagocytic activity to purify activated immune cells. Our data show that spontaneously differentiated 18-day-old EBs of the cell line CGR8 contained immune cells, which were positive for CD45, CD68, CD11b, F4/80, and CD19. Exposure of these EBs to E. coli with defined infection doses of bacterial colony-forming units (CFUs) led to a significant time-dependent reduction of CFUs, indicating the immune responses exerted by EBs. This was paralleled by an upregulation of inflammatory cytokines, that is, IL-1β and TNF-α. Western blot analysis of infected EBs indicated an upregulation of CD14 and cytochrome b-245 heavy chain (NOX2). Silencing of NOX2 significantly reduced the antibacterial capacity of EBs, which was partially explained by reduction of F4/80-positive cells. To identify, isolate, and further cultivate phagocytic active cells from differentiated EBs, a cocultivation assay of differentiated ES cells with green fluorescent protein (GFP)-labeled E. coli was established. Colocalization of GFP-labeled E. coli with cells positive for CD45, CD68, and F4/80 revealed time-dependent phagocytotic uptake, which was underlined by colocalization with the LysoTracker-Red(®) dye as well as preincubation with cytochalasin D. In conclusion, a primitive immune response with efficient phagocytosis was responsible for the antibacterial capacity of differentiated EBs.

Compare the effect of eicosapentaenoic acid and oxidized low-density lipoprotein on the expression of CD36 and peroxisome proliferator-activated receptor gamma.

There is evidence that CD36 promotes foam cell formation through internalizing oxidized LDL (ox-LDL) into macrophages; therefore, it plays a key role in pathogenesis of atherosclerosis. In addition, CD36 expression seems to be mediated by nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ). The aim of the present study was to evaluate and compare the effect of PPAR-γ ligands, eicosapentaenoic acid (EPA) as an anti-atherogenic factor and ox-LDL as an atherogenic factor on CD36 expression. Mechanism of PPAR- γ action and its ligands in CD36 expression were also investigated. Raw 264.7 macrophage cell line was treated with ox-LDL (100 and 150 μg protein/LDL) and EPA (100 and 200 μM) for 24 and 48 hours in absence or presence of PPAR-γ inhibitor, T0070907. Quantitative real-time PCR and Western-blotting were used for analysis of gene and protein expression, respectively. Raw 264.7 exposures to ox-LDL and EPA resulted in increased expression of CD36 mRNA and protein; however, mRNA and PPAR-γ protein were not up-regulated significantly. Pre-incubation of cells with T0070907 led to decreased expression of CD36 when treated with ox-LDL and EPA. It was confirmed that both EPA and ox-LDL increased CD36 expression but not PPAR-γ, and also co-treatment with PPAR-γ inhibitor decreased CD36 expression. We concluded that up-regulation of CD36 depends on PPAR-γ activation and is not related to increased expression of PPAR-γ. Induction of CD36 by EPA showed that CD36 suppression is not the means by which ω-3 fatty acids (EPA) provide protection against formation of atherosclerotic plaque.

Visfatin induces cholesterol accumulation in macrophages through up-regulation of scavenger receptor-A and CD36

As a new potential inflammatory mediator, visfatin plays an important role in inflammation and atherosclerosis. The formation of macrophage-derived foam cells occurs at the early stage of atherosclerosis and underlies the visible fatty streak. Recent studies have indicated that visfatin may be associated with the development of foam cells, but its exact effect and molecular mechanism remain unknown. This study aims to study the effect of visfatin on foamy cell formation and its underlying molecular mechanism. Visfatin levels were determined in apolipoprotein E (ApoE) knockout (KO) mice on a western diet for 16 weeks. Effects of visfatin in cholesterol accumulation were studied both in vivo and in vitro. The levels of scavenger receptors located in macrophage surface were measured in RAW264.7 cells after treatment with visfatin. Visfatin levels were much higher in ApoE KO mice than that in the control mice. Meanwhile, oxidized low-density lipoprotein induces both visfatin release from RAW264.7 cells and its cellular levels within 24 h. Visfatin promotes lipid accumulation mainly through excessive cholesterol uptake not only in RAW264.7 cells but also in peritoneal macrophages isolated from ApoE KO mice. Furthermore, visfatin induces the activation of scavenger receptors (SR)-A and cluster of differentiation (CD)36, but not that of SR-BI, ATP-binding cassette transporter (ABC)A1, or ABCG1 in RAW264.7 cells. Both transcriptional and posttranscriptional regulation may work in concert to mediate the expression of SR-A and CD36 in visfatin-treated cells. Visfatin induces cholesterol accumulation in macrophages and accelerates the process of atherosclerosis mainly through modulating the expression of SR-A and CD36.

TRIF Is Required for TLR4 Mediated Adjuvant Effects on T Cell Clonal Expansion

Toll like receptor 4 (TLR4) is an important pattern recognition receptor with the ability to drive potent innate immune responses and also to modulate adaptive immune responses needed for long term protection. Activation of TLR4 by its ligands is mediated by engagement of the adapter proteins MyD88 (myeloid differentiation factor 88) and TRIF (Toll-interleukin 1 receptor domain-containing adapter inducing interferon-beta). Previously, we showed that TRIF, but not MyD88, plays an important role in allowing TLR4 agonists to adjuvant early T cell responses. In this study, we investigated the T cell priming events that are regulated specifically by the TRIF signaling branch of TLR4. We found that TRIF deficiency prevented the TLR4 agonist lipid A from enhancing T cell proliferation and survival in an adoptive transfer model of T cell priming. TRIF deficient DC showed defective maturation as evidenced by their failure to upregulate co-stimulatory molecules in response to lipid A stimulation. Importantly, TRIF alone caused CD86 and CD40 upregulation on splenic DC, but both TRIF and MyD88 were required for CD80 upregulation. The impairment of T cell adjuvant effects and defective DC maturation in TRIF lps/lps mice after TLR4 stimulation was mainly due to loss of type I IFN production, indicating that type I interferons are central to TLR4's adjuvant effects. These results are useful for the continued development of TLR4 based vaccine adjuvants that avoid inflammatory risks while retaining beneficial immune response.

CD14 overexpression upregulates TNF-α-mediated inflammatory responses and suppresses the malignancy of gastric carcinoma cells

CD14 mediates the inflammatory response via recognition of lipopolysaccharide, which has been implicated in Helicobacter pylori (H. pylori) infections. Increasing evidence has suggested that CD14 status significantly influences the clinical outcome of H. pylori infection, which can result in gastric carcinoma. However, there is little evidence regarding the cellular impact and associated molecular basis of CD14 on gastric carcinoma cells. To address this question, we generated a CD14-overexpressing SGC-7901 gastric carcinoma cell line and analyzed the impact of CD14 expression. Our results revealed that cells overexpressing CD14 exhibited antitumor potential, including significantly decreased clonogenic ability, proliferation, metastatic invasion, as well as enhanced apoptosis, suggesting a tumor-suppressive role of CD14 in the cells. Intriguingly, we further discovered that CD14 overexpression activated NF-κB via upregulating its expression and simultaneously stimulating DNA binding activity. Upregulated NF-κB transcriptionally elevated a series of pro-inflammatory cytokines, including TNF-α, IL-1β, IL-6, and IL-12. Together, the current study utilized a CD14-overexpressing gastric cell model to determine the impacts of CD14 upregulation on cell viability, apoptosis, and migration and NF-κB-mediated inflammation.

Decoupling activation and exhaustion of B cells in spontaneous controllers of HIV infection

To define the impact of chronic viremia and associated immune activation on B-cell exhaustion in HIV infection. Progressive HIV infection is marked by B-cell anergy and exhaustion coupled with dramatic hypergammaglobulinemia. Although both upregulation of CD95 and loss of CD21 have been used as markers of infection-associated B-cell dysfunction, little is known regarding the specific profiles of dysfunctional B cells and whether persistent viral replication and its associated immune activation play a central role in driving B-cell dysfunction. Multiparameter flow cytometry was used to define the profile of dysfunctional B cells. The changes in the expression of CD21 and CD95 were tracked on B-cell subpopulations in patients with differential control of viral replication. : Although the emergence of exhausted, CD21 tissue-like memory B cells followed similar patterns in both progressors and controllers, the frequency of CD21 activated memory B cells was lower in spontaneous controllers. Our results suggest that the loss of CD21 and the upregulation of CD95 occur as separate events during the development of B-cell dysfunction. The loss of CD21 is a marker of B-cell exhaustion induced in the absence of appreciable viral replication, whereas the upregulation of CD95 is tightly linked to persistent viral replication and its associated immune activation. Thus, these dysfunctional profiles potentially represent two functionally distinct states within the B-cell compartment.

CD14 upregulation as a distinct feature of non-alcoholic fatty liver disease after pancreatoduodenectomy

To investigate the pathogenesis of non-alcoholic fatty liver disease (NAFLD) after pancreatoduodenectomy (PD). A cohort of 82 patients who underwent PD at Okayama University Hospital between 2003 and 2009 was enrolled and the clinicopathological features were compared between patients with and without NAFLD after PD. Computed tomography (CT) images were evaluated every 6 mo after PD for follow-up. Hepatic steatosis was diagnosed on CT when hepatic attenuation values were 40 Hounsfield units. Liver biopsy was performed for 4 of 30 patients with NAFLD after PD who consented to undergo biopsies. To compare NAFLD after PD with NAFLD associated with metabolic syndrome, liver samples were obtained from 10 patients with NAFLD associated with metabolic syndrome [fatty liver, n = 5; non-alcoholic steatohepatitis (NASH), n = 5] by percutaneous ultrasonography-guided liver biopsy. Double-fluorescence immunohistochemistry was applied to examine CD14 expression as a marker of lipopolysaccharide (LPS)-sensitized macrophage cells (Kupffer cells) in liver biopsy specimens. The incidence of postoperative NAFLD was 36.6% (30/82). Univariate analysis identified cancer of the pancreatic head, sex, diameter of the main pancreatic duct, and dissection of the nerve plexus as factors associated with the development of NAFLD after PD. Those patients who developed NAFLD after PD demonstrated significantly decreased levels of serum albumin, total protein, cholesterol and triglycerides compared to patients without NAFLD after PD, but no glucose intolerance or insulin resistance. Liver biopsy was performed in four patients with NAFLD after PD. All four patients showed moderate-to-severe steatosis and NASH was diagnosed in two. Numbers of cells positive for CD68 (a marker of Kupffer cells) and CD14 (a marker of LPS-sensitized Kupffer cells) were counted in all biopsy specimens. The number of CD68+ cells in specimens of NAFLD after PD was significantly increased from that in specimens of NAFLD associated with metabolic syndrome specimens, which indicated the presence of significantly more Kupffer cells in NAFLD after PD than in NAFLD associated with metabolic syndrome. Similarly, more CD14+ cells, namely, LPS-sensitized Kupffer cells, were observed in NAFLD after PD than in NAFLD associated with metabolic syndrome. Regarding NASH, more CD68+ cells and CD14+ cells were observed in NASH after PD specimens than in NASH associated with metabolic syndrome. This showed that more Kupffer cells and more LPS-sensitized Kupffer cells were present in NASH after PD than in NASH associated with metabolic syndrome. These observations suggest that after PD, Kupffer cells and LPS-sensitized Kupffer cells were significantly upregulated, not only in NASH, but also in simple fatty liver. NAFLD after PD is characterized by both malnutrition and the up-regulation of CD14 on Kupffer cells. Gut-derived endotoxin appears central to the development of NAFLD after PD.

A Plant Triterpenoid Avicin D Stimulates Adipocytic Differentiation of Bone Marrow Stromal Cells and Promotes Their Pro-Survival Effects On Acute Monoblastic Leukemia Cells

Abstract 4315A natural triterpene Avicin D induces apoptosis in various tumor cells and regulates cellular metabolism via Glucocorticoid receptor (GR) signalling, known to be involved in adipocyte differentiation (Tang, Annu Rev Biochem. 2012;81:715). Since adipocytes represent an essential component of the aging bone marrow (BM) microenvironment (Tabe, Blood 2004;103:1815), and promote monocytic differentiation and survival of monoblastic leukemia cells (Tabe, ASH, 2011), we examined the potential of Avicin D to modulate BM adipocytes and its effects on the survival of the leukemic cells.In mature adipocytes derived from BM mesenchymal stem cells (MSCs), Avicin D (1ƒE′M, 48 hrs) significantly increased the number of lipid vesicles without apoptosis induction or significant cell cycle arrest. This was associated with upregulation of adipose-specific genes, PPARG and fatty acid binding protein 4 (FABP4), and inflammation-related haptoglobin (HP) gene (p<0.005, Figure 1). Avicin D further enhanced leptin release from adipocytes and inflammatory cytokines production, IL-6 and IL-8, from both MSCs and adipocytes (Figure 2). Of note, Avicin D increased pro-survival Bcl-2 mRNA expression in adipocytes (fold increase compared to MSCs: MSCs+Avicin D 1.0±0, adipocytes 1.8±0.1, adipocytes+Avicin D 4.4±0.6, p=0.02).We next investigated the effects of MSCs and adipocytes pre-treated with 1mM Avicn D for 24 hours on co-cultured monoblastic leukemia cell line U937. Avicin D (1ƒE′M) moderately (26±5 %) inhibited cell proliferation of U937 cells cultured alone as detected by MTT assay. Serum-starvation induced cell death in U937 cells was inhibited by MCS or adipocyte co-culture, and further blocked by Avicin D-pretreated adipocytes, which was accompanied with cell cycle arrest (sub-G1 fraction; control U937 36.1±7.1%, co-culture with MSC 17.9±4.1%, MSC+Avicin D 20.9±3.9%, adipocyte 16.9±2.9, adipocyte+Avicin D 11.5±0.8%, p=0.03, G0/G1 phase; control 39.1±5.9%, with MSC 44.3±1.0%, MSC+Avicin D 40.3±1.3%, adipocyte 40.6±1.3, adipocyte+Avicin D 50.4±2.3%, p=0.03). Co-culture of U937 cells with Avicin D-pretreated adipocytes induced upregulation of PPARG and CD36, markers of monocytes/macrophages maturation in U937 cells (fold increase compared to control U937: PPARG: co-culture with adipocytes 2.1±0.4, adipocytes+Avicin D 13.8±6.2; CD36: adipocytes 2.2±0.4, adipocytes+Avicin D 4.7±2.9). Co-culture with Avicin D-pretreated adipocytes also caused 3.1 ±0.4 fold increase of BCL2 mRNA in U937 cells compared to the one of co-cultured with control adipocytes (p=0.02). The purity of U937 cells separated from adipocytes was confirmed by lack of CD90 mRNA expression by PCR. Utilization of the proteomic technology of isobaric tags for relative and absolute quantitation (iTRAQ) with two-dimensional-liquid chromatography-tandem mass spectrometry allowed the identification of 1,634 proteins. We found changes in 14 proteins in U937 cells co-cultured with Avicin D-pretreated adipocytes compared to untreated adipocytes. Among 13 down-regulated proteins, three are involved in pyruvate metabolism (Glyoxalase I; p=0.01, Lactate dehydrogenase B; p=0.02, Pyruvate kinase; p=0.03), and four proteins participate in cell cycle progression (DNA replication licensing factor MCM4, MCM5; p=0.02, p=0.03, DNA-dependent protein kinase; p=0.02, Interleukin enhancer-binding factor 3; p=0.005). Voltage-dependent anion-selective channel protein 2, which is involved in the mitochondrial apoptotic pathway via regulation of Bcl-2, and an enzymatic antioxidant Superoxide dismutase were up-regulated (p=0.04, p=0.03). These data indicate that U937 cells co-cultured with Avicin D pretreated adipocytes were induced to undergo cell cycle arrest, escape apoptosis with down-regulation of glucose metabolism.Altogether, these results suggest that Avicin D induces adipocytic differentiation of BM-derived stromal cells, promotes production of leptin and inflammatory cytokines, which in turn supports survival of monocytic leukemia cells. These findings suggest a contributory role of the aging “pro-inflammatory” bone marrow microenvironment in the reduced efficacy of cytotoxic chemotherapy which is prevalent in elderly AML patients. [Display omitted] Disclosures:No relevant conflicts of interest to declare.