Expression Of Lymphocyte Function-associated Antigen-1 Research Articles

LFA-1 regulated by IL-2/STAT5 pathway boosts antitumor function of intratumoral CD8+ T cells for improving anti-PD-1 antibody therapy

ABSTRACT Anti-PD-1 antibody therapy has achieved success in tumor treatment; however, the duration of its clinical benefits are typically short. The functional state of intratumoral CD8+ T cells substantially affects the efficacy of anti-PD-1 antibody therapy. Understanding how intratumoral CD8+ T cells change will contribute to the improvement in anti-PD-1 antibody therapy. In this study, we found that tumor growth was not arrested after the late administration of anti-PD-1 antibody and that the antitumor function of CD8+ T cells decreased with tumor progression. The results of the RNA sequencing of CD8+ T cells infiltrating the tumor site on days 7 and 14 showed that the cell adhesion molecule Lymphocyte Function-associated Antigen-1 (LFA-1) participates in regulating the antitumor function of CD8+ T cells and that decreased LFA-1 expression in intratumoral CD8+ T cells is associated with tumor progression. By analyzing the Gene Expression Omnibus (GEO) database and our results, we found that the antitumor function of intratumoral CD8+ T cells with high LFA-1 expression was stronger. The formation of immune synapses is impaired in Itgal-si CD8+ T cells, resulting in decreased anti-tumor function. LFA-1 expression in intratumoral CD8+ T cells is regulated by the IL-2/STAT5 pathway. The combination of IL-2 and anti-PD-1 antibody effectively enhanced LFA-1 expression and the antitumor function of intratumoral CD8+ T cells. The adoptive transfer of OT-1 T cells overexpressing LFA-1, STAT5A, or STAT5B resulted in higher antitumor function, deferred tumor growth, and prolonged survival. These findings indicate that LFA-1-mediated immune synapse acts as a regulator of the antitumor function of intratumoral CD8+ T cells, which can be applied to improve anti-PD-1 antibody therapy.

CCL5 promotes LFA-1 expression in Th17 cells and induces LCK and ZAP70 activation in a mouse model of Parkinson's disease.

Parkinson's disease (PD), which is associated to autoimmune disorders, is characterized by the pathological deposition of alpha-synuclein (α-Syn) and loss of dopaminergic (DA) neurons. Th17 cells are thought to be responsible for the direct loss of DA neurons. C-C chemokine ligand 5 (CCL5) specifically induces Th17 cell infiltration into the SN. However, the specific effect of CCL5 on Th17 cells in PD and the relationship between CCL5 and lymphocyte function-associated antigen-1 (LFA-1) expression in Th17 cells are unknown. We evaluated the effects of CCL5 on LFA-1 expression in Th17 cells in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and examined Th17 cell differentiation upon CCL5 stimulation in vitro. Furthermore, we assessed the effects of CCL5 on tyrosine kinase zeta-chain-associated protein kinase 70 (ZAP70) and lymphocyte-specific protein tyrosine kinase (LCK) activity in CCL5-stimulated Th17 cells in vivo and in vitro. CCL5 increased the proportion of peripheral Th17 cells in MPTP-treated mice, LFA-1 expression on Th17 cells, and Th17 cell levels in the SN of MPTP-treated mice. CCL5 promoted Th17 cell differentiation and LFA-1 expression in naive T cells in vitro. Moreover, CCL5 increased Th17 cell differentiation and LFA-1 expression by stimulating LCK and ZAP70 activation in naive CD4+ T cells. Inhibiting LCK and ZAP70 activation reduced the proportion of peripheral Th17 cells and LFA-1 surface expression in MPTP-treated mice, and Th17 cell levels in the SN also significantly decreased. CCL5, which increased Th17 cell differentiation and LFA-1 protein expression by activating LCK and ZAP70, could increase the Th17 cell number in the SN, induce DA neuron death and aggravate PD.

LFA-1 knockout inhibited the tumor growth and is correlated with treg cells

Cancer immunotherapy has been proven to be clinically effective in multiple types of cancers. Lymphocyte function-associated antigen 1 (LFA-1), a member of the integrin family of adhesion molecules, is expressed mainly on αβ T cells. LFA-1 is associated with tumor immune responses, but its exact mechanism remains unknown. Here, two kinds of mice tumor model of LFA-1 knockout (LFA-1−/−) mice bearing subcutaneous tumor and ApcMin/+;LFA-1−/− mice were used to confirm that LFA-1 knockout resulted in inhibition of tumor growth. Furthermore, it also demonstrated that the numbers of regulatory T cells (Treg cells) in the spleen, blood, mesenteric lymph nodes were decreased in LFA-1−/− mice, and the numbers of Treg cells in mesenteric lymph nodes were also decreased in ApcMin/+;LFA-1−/− mice compared with ApcMin/+ mice. LFA-1 inhibitor (BIRT377) was administered to subcutaneous tumor-bearing LFA-1+/+ mice, and the results showed that the tumor growth was inhibited and the number of Treg cells was reduced. The analysis of TIMER tumor database indicated that LFA-1 expression is positively associated with Treg cells and TNM stage. Conclusively, this suggests that LFA-1 knockout would inhibit tumor growth and is correlated with Treg cells. LFA-1 may be one potential target for cancer immunotherapy.62QPUkCarP1aXjSsQjtmWhVideo

Understanding the Role of LFA-1 in Leukocyte Adhesion Deficiency Type I (LAD I): Moving towards Inflammation?

LFA-1 (Lymphocyte function-associated antigen-1) is a heterodimeric integrin (CD11a/CD18) present on the surface of all leukocytes; it is essential for leukocyte recruitment to the site of tissue inflammation, but also for other immunological processes such as T cell activation and formation of the immunological synapse. Absent or dysfunctional expression of LFA-1, caused by mutations in the ITGB2 (integrin subunit beta 2) gene, results in a rare immunodeficiency syndrome known as Leukocyte adhesion deficiency type I (LAD I). Patients suffering from severe LAD I present with recurrent infections of the skin and mucosa, as well as inflammatory symptoms complicating the clinical course of the disease before and after allogeneic hematopoietic stem cell transplantation (alloHSCT); alloHSCT is currently the only established curative treatment option. With this review, we aim to provide an overview of the intrinsic role of inflammation in LAD I.

Abstract 2842: 6-gingerol attenuates metastasis in aged mice model of colorectal cancer through modulation of epithelial-mesenchymal transition mediators genes and e-cadherin upregulation

Abstract Colorectal cancer (CRC) is the third most common cancer in America, and the third cause of cancer related death. Metastasis is the major cause of death in patient with CRC. Many CRC are likely to spread from primary site to the other parts of the body before and after detection of malignant tumor. 6-gingerol, the bioactive component of fresh ginger have been reported to have myriad of biological activities including anti-inflammatory and antioxidant properties. We have previously reported the anti-CRC effect of 6-gingerol. However there is dearth of information on the anti-metastatic effect 6-gingerol in CRC. Thus, the effect of 6-gingerol on epithelial-mesenchymal transition mediators' genes and E-Cadherin repression in aged mice model of CRC was assessed in this study. Following institutional ethical approval. Aged male BALB/c mice (10 months) were divided into four groups of 10 mice each. Mice were fed with AIN-93 diet and allowed access to water ad libitum. Group 1 mice serve as control, group 2 mice received 6-gingerol 10mg/kg/day by oral gavage for 10 weeks. Group 3 mice received a single dose of azoxymethane (AOM) 10mg/kg (iP) and on the seventh day they received three cycles of dextran sulfate sodium (DSS) 2% (W/V) in drinking water ( each cycle is define as one week of DSS followed by two weeks of plain drinking water) Group 4 mice received 6-gingerol 10mg/kg/day by oral gavage in combination with single dose of azoxymethane 10mg/kg (iP) and on the seventh day they received three cycles of dextran sulfate sodium salt 2% (W/V) in drinking water. Mice were humanely sacrificed under anesthesia and colon tissues were processed for RT-PCR and multiplex immunohistochemistry analysis. Mice that received both 6-gingerol and AOM and DSS showed a significant decreased expression of Lymphocyte function-associated antigen-1, N-cadherin, SNAIL 1, ZEB 1, AP4 and HMGA1 with concomitant Upregulation miR-34, miR-15a, miR-218 and miR-302 expression as compared with the AOM and DSS only group. The result obtained from this study showed 6-gingerol inhibited metastasis through modulation of epithelial-mesenchymal transition mediators' genes and E-Cadherin upregulation, and as such 6-gingerol could be a promising anti-metastatic agent in CRC treatment. Citation Format: Babajide Oluwaseun Ajayi, Ayomiposi Adenigba, Anuoluwapo Adeshina. 6-gingerol attenuates metastasis in aged mice model of colorectal cancer through modulation of epithelial-mesenchymal transition mediators genes and e-cadherin upregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2842.

Identification of neutrophil \u03b22-integrin LFA-1 as a potential mechanistic biomarker in ANCA-associated vasculitis via microarray and validation analyses

BackgroundLeukocyte activation by anti-neutrophil cytoplasmic antibody (ANCA) and the subsequent leukocyte–endothelium interaction play a key role in the development of endothelial damage in ANCA-associated vasculitis (AAV). In contrast to that of leukocyte activation, the exact role of the leukocyte–endothelium interaction via integrin remains unclear. Here, we performed microarray and validation analyses to explore association between the expression levels of lymphocyte function-associated antigen-1 (LFA-1) and the clinical characteristics of patients with AAV.MethodsWe performed gene set enrichment analysis (GSEA) to identify the functional gene sets differentially expressed between patients with AAV and other types of vasculitis and the healthy controls (HCs). Flow cytometry was performed to validate the GSEA results. Treatment-naïve patients were monitored until 24 weeks of treatment. To examine the role of LFA-1 in the neutrophil–endothelium interaction, we performed a leukocyte adhesion and transmigration assay using peripheral blood and human umbilical vein endothelial cells (HUVECs).ResultsGSEA revealed that the molecular pathways involving integrin-related genes were significantly upregulated in patients with AAV compared to that in patients with other types of vasculitis and the HCs. Flow cytometry revealed that the percentage of neutrophils expressing LFA-1 was significantly higher in patients with AAV than in those with large-vessel vasculitis or polyarteritis nodosa and the HCs. LFA-1 levels in the neutrophils were higher in patients with MPO-ANCA-positive expression than in those with a positive PR3-ANCA expression and correlated with the peripheral eosinophil count, serum rheumatoid factor titre, serum C-reactive protein levels, and the vasculitis activity score of systemic and chest components. After 24 weeks of treatment, including prednisolone, cyclophosphamide, rituximab, azathioprine, methotrexate, and/or tacrolimus, neutrophil LFA-1 expression remained high in the non-responder patients, but decreased in the responder patients. The in vitro assay showed that leukocyte migration toward HUVECs was dependent on the interaction between LFA-1 and intercellular adhesion molecule-1 (ICAM1); the migration of leukocytes was inhibited by blocking the adhesion of LFA-1 to ICAM1.ConclusionsThe expression of LFA-1 in neutrophils is increased in patients with AAV. Neutrophil LFA-1 levels correlate with the clinical features of AAV. Inhibiting the adhesion of LFA-1 and ICAM1 impedes the neutrophil–endothelium interaction and may have a therapeutic role in AAV.

Hyperglycemia Decreases Epithelial Cell Proliferation and Attenuates Neutrophil Activity by Reducing ICAM-1 and LFA-1 Expression Levels.

Delayed repair is a serious public health concern for diabetic populations. Intercellular adhesion molecule 1 (ICAM-1) and Lymphocyte function-associated antigen 1 (LFA-1) play important roles in orchestrating the repair process. However, little is known about their effects on endothelial cell (EC) proliferation and neutrophil activity in subjects with hyperglycemia (HG). We cultured ECs and performed a scratch-closure assay to determine the relationship between ICAM-1 and EC proliferation. Specific internally labeled bacteria were used to clarify the effects of ICAM-1 and LFA-1 on neutrophil phagocytosis. Transwell assay and fluorescence-activated cell sorting analysis evaluated the roles of ICAM-1 and LFA-1 in neutrophil recruitment. ICAM-1+/+ and ICAM-1–/– mice were used to confirm the findings in vivo. The results demonstrated that HG decreased the expression of ICAM-1, which lead to the low proliferation of ECs. HG also attenuated neutrophil recruitment and phagocytosis by reducing the expression of ICAM-1 and LFA-1, which were strongly associated with the delayed repair.

Effects of physiochemical characteristic of nano-sized TiO2 on the adhesion of monocytes to endothelial cells

Nano-sized titanium dioxide (TiO2) particles are produced on a large scale and are widely used. However, the effects of exposure to nano-sized TiO2 particles on the cardiovascular system remain elusive. The present study investigated how the crystal structure and surface characteristics of nano-sized TiO2 particles affect the adhesion of monocytes to endothelial cells, which is an essential process in atherosclerogenesis. Human umbilical vein endothelial cells (HUVECs) and human monocytic leukemia cells (THP-1) were exposed to anatase (NM102), rutile hydrophobic (NM103), and rutile hydrophilic (NM104) TiO2 nanoparticles. Incubation of HUVECs with NM102, NM103, or NM104 at 100 μg/ml significantly reduced cell viability, and cell viability was also significantly reduced after exposure to 75 μg/ml of the anatase particles (NM102). Brief exposure to NM102 and NM103 increased the level of intercellular adhesion molecule-1 (ICAM-1) in HUVECs. Exposure to NM102 also upregulated the expression of lymphocyte function-associated antigen-1 (LFA-1) in THP-1 cells, resulting in enhanced adhesion of these cells to HUVECs. The amount of titanium uptake of NM102 in cells was higher than that of NM103 or NM104, as evidenced by inductively coupled plasma optical emission spectroscopy (ICP-OES). To examine the effects of long-term exposure to nano-sized TiO2 on the process of atherosclerosis, apolipoprotein E deficient (ApoE−/−) mice were exposed to TiO2 NPs (NM102, NM103, or NM104 at 10 or 40 μg/mouse) by pharyngeal aspiration once every other week for 10 weeks. As the results, NM102 (40 μg/mouse) increased plaque formation in the aorta, and this increase correlated with a significant upregulation of ICAM-1 and F4/80 expression in the aorta. Anatase, but not rutile, TiO2 nanoparticles promoted the adhesion of monocytes to endothelial cells, and enhanced atherosclerogenesis in a susceptible animal model.

Regulation of LOX-1 on adhesion molecules and neutrophil infiltration in mouse Aspergillus fumigatus keratitis.

To determine whether lectin-like ox-LDL receptor (LOX-1) regulates adhesion molecules expression and neutrophil infiltration in Aspergillus fumigatus (A. fumigatus) keratitis of C57BL/6 mice. C57BL/6 mice were pretreated with a neutralizing antibody to LOX-1 (5 µg/5 µL) or control nonspecific IgG (5 µg/5 µL), LOX-1 inhibitor Poly-I (2 µg/5 µL) or PBS by subconjunctival injection. Fungal keratitis (FK) mouse models of C57BL/6 mice were established by scraping corneal central epithelium, smearing A. fumigatus on the corneal surface and covering the eye with contact lenses. The corneal response to infection was assessed via clinical score. The mRNA levels of the adhesion molecules intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), P-selectin and E-selectin were tested in control and infected corneas by reverse transcription-polymerase chain reaction (RT-PCR). The protein levels of ICAM-1 were evaluated by immunofluorescence (IF) and Western blot. Neutrophils were extracted from the abdominal cavity of C57BL/6 mice followed by pretreatment using antibody to LOX-1 (10 µg/mL) or control nonspecific IgG (10 µg/mL), the Poly-I (4 µg/mL) or PBS. The cells were then stimulated with A. fumigatus and tested mRNA and protein levels of lymphocyte function-associated antigen-1 (LFA-1) using RT-PCR and Western blot. IF and myeloperoxidase (MPO) assays were used to assess neutrophil infiltration in mice corneas. Pretreatment of LOX-1 antibody or the Poly-I reduced the degree of inflammation of cornea and decreased the clinical FK score compared with pretreatment of IgG or PBS (both P<0.01). And these pretreatment also displayed an obvious decline in the mRNA levels of ICAM-1, VCAM-1, P-selectin, E-selectin and LFA-1 expression compared with control groups (all P<0.01). Furthermore, pretreated with LOX-1 antibody or Poly-I, the protein levels of ICAM-1 and LFA-1 also decreased compared with control groups (all P<0.05). Neutrophil infiltration in the cornea was significantly reduced after pretreatment of LOX-1 antibody or Poly-I compared with control groups by IF and MPO assays (both P<0.01). Inhibition of LOX-1 can decrease the expression of adhesion molecules and reduce neutrophil infiltration in A. fumigatus infected corneas of C57BL/6 mice.

Dysregulation of endothelial cell specific molecule-1 expression during urosepsis-induced acute lung injury in rabbits

Objective To explore the expression of endothelial cell specific molecule-1 (ESM-1) and inflammatory factors during urosepsis-induced acute lung injury (ALI) in rabbits, and the potential mechanism. Methods Urosepsis-induced ALI models in rabbits were assigned into three groups: control group, sham group and urosepsis group (0, 6, 12 and 36 h according to time points pre-scheduled). The rabbit urosepsis model was established by artificial high pressure in the infected pelvis. Lung histomorphological changes were observed by light microscope. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, ESM-1, lymphocyte function associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) in serum were analyzed by enzyme linked immunosorbent assay (ELISA). The expression of ESM-1, LFA-1 and ICAM-1 in serum was detected by ABC immunohistochemistry, and further the ESM-1/LFA-1 rate in lung tissue was calculated. Results As compared with the control group and sham group, urosepsis group had serious lung injury. The levels of serum TNF-α, IL-1β and IL-6 were elevated significantly in urosepsis group. After 6, 12, 24 and 36 h, the levels of TNF-α were (63.65±3.07), (128.17±4.26), (99.24±7.97), (49.36±6.09) ng/L; the levels of IL-1β were (232.77±21.54), (481.21±20.84), (220.23±22.21), (105.25±23.46) ng/L; the levels of IL-6 were (72.62±4.42), (122.51±6.77), (82.22±4.23), (60.05±2.82) ng/L. The expression levels in the urosepsis group were significantly higher than those in the control group and the sham group at each time point (After 36 h, TNF-α: F=96.932, P=0.000; IL-1β: F=9.001, P=0.007; IL-6: F=5.293, P=0.030). The expression of serum LFA-1 and ICAM-1 was increased over time in urosepsis group. After 6, 12, 24 and 36 h, the levels of LFA-1 were (12.50±5.71), (23.16±6.84), (45.04±7.65), (61.38±9.87) ng/L; the levels of ICAM-1 were (780.67±66.89), (1 034.16±72.33), (1 420.10±87.25), (1 834.23±88.46) ng/L, which were significantly different from those in the control group and the sham group (After 36 h, LFA-1: F=85.612, P=0.000; ICAM-1: F=456.901, P=0.000). Meantime, the levels of ESM-1 expression and ESM-1/LFA-1 rate in the lung tissue during urosepsis increased in the early stage of urosepsis but declined over time. The levels of LFA-1 were: 0.139±0.017, 0.274±0.024, 0.120±0.035, 0.089±0.031; the ESM-1/LFA-1 rate was: 1.188±0.019, 1.473±0.015, 0.529±0.020, 0.263±0.017, which were significantly different from those in the control group and the sham group (After 36 h, ESM-1: F=13.190, P=0.002; ESM-1/LFA-1: F=891.411, P=0.000). Conclusion The expression changes of ESM-1 may suggest the development process during urosepsis-induced ALI. The present study may offer beneficial reference for treating ALI, and decreasing multiple organs failure in earlier phase clinically. Key words: Endothelial cell specific molecule-1; Lymphocyte function associated antigen-1/Intercellular adllesion molecule-1; Urosepsis; Acute lung injury

Luteolin suppresses inflammation through inhibiting cAMP-phosphodiesterases activity and expression of adhesion molecules in microvascular endothelial cells.

Luteolin, an anti-inflammatory ingredient found in the Chinese herb Folium perillae, can inhibit not only the cyclic adenosine monophosphate (cAMP)-phosphodiesterases (PDEs) activity of neutrophils, but also the expression of lymphocyte function-associated antigen-1 in neutrophils, both of which result in a decrease in the adhesion between neutrophils and microvascular endothelial cells. However, the effect of luteolin on the cAMP-PDEs activity and expression of adhesion molecules in endothelial cells are not clear. In the present study, primary rat pulmonary microvascular endothelial cells and a lipopolysaccharide-induced rat acute pneumonia model were used to explore the role of luteolin on cAMP-PDEs activity, expression of adhesion molecules, and leukocyte infiltration. We demonstrate that rat pulmonary microvascular endothelial cells expressed high levels of cAMP-PDEs, specifically PDE4, and further luteolin exhibited dose-dependent inhibition on the activity of cAMP-PDEs or PDE4 in endothelial cells. Luteolin also had a significant inhibitory effect on the expression of vascular cell adhesion molecule (VCAM)-1, but not intracellular cell adhesion molecule (ICAM)-1 in microvascular endothelial cells. Further, we show that luteolin decreased the levels of soluble ICAM-1 (sICAM-1), but not soluble E-selectin in the serum of rats subjected to acute pneumonia. We also show that luteolin treatment decreased the wet/dry weight ratio of lung tissue and reduced the total number of serum leukocytes in a dose-dependent manner in a rat acute pneumonia model. In conclusion, these results demonstrate that luteolin suppresses inflammation, at least in part, through inhibiting both cAMP-PDEs or PDE4 activity and the expression of VCAM-1 (in vitro) and sICAM-1 (in vivo) in endothelial cells.

Luteolin Partially Inhibits LFA-1 Expression in Neutrophils Through the ERK Pathway.

Luteolin inhibits the adhesion of neutrophils to microvascular endothelial cells and plays an important anti-inflammatory role, owing to its mechanism of suppressing the expression of lymphocyte function-associated antigen-1 (LFA-1) in the neutrophils. Our study deals with the different signaling pathways participating in LFA-1 expression in neutrophils along with the regulation of luteolin in order to elucidate new anti-inflammatory targets of luteolin, thus providing a basis for clinical applications. In our study, neutrophils were separated using density gradient centrifugation and the cAMP levels were determined using ELISA. Additionally, phosphorylation levels of p38 mitogen-activated protein kinase (MAPK), extracellular regulated protein kinase (ERK), phosphatidylinositol-3-kinase (PI3K), and Janus kinase (JAK) were also detected by Western blotting. LFA-1 expression was estimated using flow cytometry. The results showed that inhibiting agents used against p38 MAPK, ERK, PI3K, and JAK could significantly inhibit LFA-1 expression on neutrophils (p< 0.05, p< 0.01). Luteolin also induced a noteworthy elevation of cAMP in neutrophil supernatants (p< 0.01). It could also significantly inhibit ERK phosphorylation (p< 0.05, p< 0.01), and had no obvious effect on p38 MAPK phosphorylation in neutrophils (p> 0.05). However, phosphorylation of PI3K and JAK was not detected in neutrophils. To conclude, the p38 MAPK, ERK, PI3K, and JAK pathways are involved in the regulation of LFA-1 expression in neutrophils, and luteolin partially inhibits LFA-1 expression by increasing cAMP levels and suppressing ERK phosphorylation.

IL-10 inducible CD8+ regulatory T-cells are enriched in patients with multiple myeloma and impact the generation of antigen-specific T-cells.

Tumor-mediated immunosuppression via regulatory T-cells is a key player among the various immune-escape mechanisms in multiple myeloma. We analyzed the generation, distribution, function and immunophenotype of CD8+CD28- regulatory T-cells in patients with multiple myeloma. Functionality of CD8+CD28- T-cells was assessed by immunological assays using ex vivo generated antigen-specific T-cells from patients with plasma cell dyscrasias and healthy donors. Detailed analysis of distribution, immunophenotype and cytotoxic potential of CD8+CD28- T-cells was performed by flow cytometry and ELISA. We found that the amount of CD8+CD28- T-cells was directly correlated with the suppression of antigen-specific T-cell responses in patients with plasma cell dyscrasia. Analyzing the CD8+CD28- T-cells in detail, increased numbers of these cells were observed in the bone marrow (i.e., tumor microenvironment) of patients with plasma cell dyscrasia. Furthermore, we identified the expression of lymphocyte function-associated antigen 1 (LFA-1) as a marker of immunosuppression and defined the CD8+CD28-CD57+LFA-1high population as the relevant immunosuppressive compartment. These regulatory T-cells act as immunosuppressors via soluble factors and incubation with IL-10 augmented their immunosuppressive capacity. The immunosuppressive regulatory network of IL-10 and the CD8+CD28-CD57+LFA-1high regulatory T-cells show unique characteristics and contribute to the tumor immune escape mechanism in patients with multiple myeloma.

Abstract 4618: TGF-B upregulates GSK3B and mediates NK dysfunction in cancer

Abstract Transforming growth factor-B (TGF-B) is an important regulator of tumorigenesis. Initially, it was discovered to have anti-cancer activities by promoting apoptosis and preventing hyperproliferation of cells. However, abundant presence of TGF-B in the tumor microenvironment is known to hinder cancer eradication by suppressing anti-tumor activities of immune cells. The molecular switches that regulate the role of TGF-B are not fully understood. One main target of TGF-B-mediated immune cell dysfunction are natural killer (NK) cells. NK cells are innate immune cells that lyse virally-infected and cancer cells. Recently, we have discovered that glycogen synthase kinase 3-beta (GSK3B) upregulation in NK cells leads to NK dysfunction. Another study has indicated that GSK3 phosphorylates SMAD3 to inhibit TGF-B-mediated growth dysfunction in AML12 cells. In addition, GSK3B inhibition has been linked to increased sensitivity of cancer cells to NK killing but the role of GSK3B in NK function is understudied. This study examines how the role that GSK3B has on TGF-B-mediated NK cell dysfunction. Methods: NK cells were isolated from the peripheral blood of healthy donors and expanded in vitro for 14 days. NK cells were either treated with or without 5ng/mL TGF-B for 72 hours, and GSK3B expression, and the expression of NK activating receptors was measured via flow cytometry. In addition, GSK3B expression is abrogated using a siRNA in NK cells. The NK cells were treated with or without TGF-B, and NK cell cytotoxicity is measured with a fluorometric cytotoxicity assay. Results: TGF-B pretreatment of NK cells led to 2-fold GSK3B expression in NK cells. TGF-B pretreatment led to decreased expression of NK activating receptors NKp46 and NKG2D. Also, TGF-B led to decreased expression of lymphocyte function-associated antigen-1 (LFA-1), an adhesion molecule necessary for NK cells to adhere to target cells prior to lysis of the target cells. TGF-B pretreatment of NK cells led to 33.3% reduced killing of both leukemic and solid tumor targets. Pharmacologic and genetic abrogation of GSK3 minimized TGF-B-mediated NK dysfunction as measured by calcein-AM based cytotoxicity assays. Importantly, inhibiting GSK3B activity with TGF-B treatment rescued NK cell cytotoxic function. Discussion: Our data suggests that TGF-B leads to upregulated GSK3B expression, and downregulation of NK activating receptors. In addition, TGF-B reduced NK killing of cancer cells. We believe that TGF-B-mediated NK dysfunction is facilitated by GSK3B upregulation. Further studies are underway to determine how TGF-B affects the expression of other NK receptors, and to elucidate the mechanism by which TGF-B directs GSK3B upregulation. Citation Format: Evelyn Ojo, Folashade Otegbeye, Stephen Moreton, David Wald. TGF-B upregulates GSK3B and mediates NK dysfunction in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4618. doi:10.1158/1538-7445.AM2017-4618

Luteolin prevents fMLP-induced neutrophils adhesion via suppression of LFA-1 and phosphodiesterase 4 activity

Luteolin is an active ingredient found early from Folium perillae and Flos lonicerae, and has a specific inhibition on phosphodiesterase 4 (PDE4) activity in vitro. Researches show luteolin has pharmacological effects of anti-inflammation, anti-anaphylaxis, antitumor, antioxidant, protection of nervous system and so on, and has mainly been used for the treatment of respiratory inflammatory diseases, cancer and cardiovascular disease in clinic. PDE4, specific to hydrolyze cyclic AMP (cAMP), is considered to be a new anti-inflammatory target due to the decisive role on cAMP signal in inflammatory cells such as neutrophils. In order to explore the anti-inflammatory mechanism, we further studied the effects of luteolin on the activity and expression of PDE4, the expression of lymphocyte function-associated antigen-1 (LFA-1) and macrophage-1 (MAC-1) in neutrophils, and the adhesion of neutrophils and endothelial cells. The results showed that luteolin had a dose-dependent inhibition on both bare PDE4 activity and PDE4 in cultured neutrophils, and had an obviously promotive effect on gene expressions of PDE4A, 4B and 4D in later period. Luteolin had a significant inhibitory effect on neutrophils adhesion and LFA-1 expression in early stage, and had no obvious effect on MAC-1 expression. Therefore, luteolin can inhibit LFA-1 expression of neutrophils, then inhibit the adhesion of neutrophils and endothelial cells, and the mechanism is at least related with the inhibition of PDE4 activity.

Expression and targeting of lymphocyte function-associated antigen 1 (LFA-1) on white blood cells for treatment of allergic asthma.

Allergic asthma is a chronic respiratory disease that results from an exaggerated inflammatory response in the airways. Environment stimuli, such as pollen and HDM, cause activation and migration of inflammatory WBCs into the respiratory tract, where they cause lung damage. Migration of these WBCs is dependent on the active configuration of the β2 integrin LFA-1. The experimental therapeutic agent LtxA specifically targets active LFA-1 and causes cell death. We investigated the association between LFA-1 and allergic asthma and hypothesized that targeting LFA-1 with LtxA could be an attractive strategy for treatment of the condition. We examined LFA-1 (CD11a) levels on PBMCs from patients with allergic asthma compared with healthy controls. Patients exhibited a significantly higher percentage of PBMCs expressing LFA-1 than healthy controls. Furthermore, the level of LFA-1 expression on patient PBMCs was greater than on healthy PBMCs. We identified a unique cellular population in patients that consisted of CD4(-) CD11a(hi) cells. We also evaluated LtxA in a HDM extract-induced mouse model for allergic asthma. LtxA caused resolution of disease in mice, as demonstrated by a decrease in BALF WBCs, a reduction in pulmonary inflammation and tissue remodeling, and a decrease in proinflammatory cytokines IL-4, IL-5, IL-9, IL-17F, and IL-23α in lung tissue. LFA-1 may serve as an important marker in allergic asthma, and the elimination of activated WBCs by use of LtxA could be a viable therapeutic strategy for treating patients with this condition.

Extract fromAcanthopanax senticosusprevents LPS-induced monocytic cell adhesion via suppression of LFA-1 and Mac-1

A crude extract from Acanthopanax senticosus (AS) has drawn increased attention because of its potentially beneficial activities, including anti-fatigue, anti-stress, anti-gastric-ulcer, and immunoenhancing effects. We previously reported that AS crude extract exerts anti-inflammatory activity through blockade of monocytic adhesion to endothelial cells. However, the underlying mechanisms remained unknown, and so this study was designed to investigate the pathways involved. It was confirmed that AS extract inhibited lipopolysaccharide (LPS)-induced adhesion of monocytes to endothelial cells, and we found that whole extract was superior to eleutheroside E, a principal functional component of AS. A series of PCR experiments revealed that AS extract inhibited LPS-induced expression of genes encoding lymphocyte function-associated antigen-1 (LFA-1) and macrophage-1 antigen (Mac-1) in THP-1 cells. Consistently, protein levels and cell surface expression of LFA-1 and Mac-1 were noticeably reduced upon treatment with AS extract. This inhibitory effect was mediated by the suppression of LPS-induced degradation of IκB-α, a known inhibitor of nuclear factor-κB (NF-κB). In conclusion, AS extract exerts anti-inflammatory activity via the suppression of LFA-1 and Mac-1, lending itself as a potential therapeutic galenical for the prevention and treatment of various inflammatory diseases.

Leishmania donovani: Influence of anti-leishmanial therapy on expression of lymphocyte function-associated antigen-3 and its relevance to pathogenisis in visceral leishmaniasis

Lymphocyte function associated antigen 3 (LFA-3) is known as adhesion molecule with its role in T-cell activation signaling as well as in Foxp3 expression. Its influences on IL-10 production is also available, whose role in pathogenesis is well documented. However, this molecule is not yet directly addressed for its association with visceral leishmaniasis (VL). We investigated the relationship between Leishmania donovani infection and expression of LFA-3 in VL patients in their pre and post treatment stage through this case control study. Present study reports L. donovani mediated expression of LFA-3 on CD14+ monocytes in human VL. Active cases of VL was observed with 2.91-fold increased mean florescence intensity (MFI) of LFA-3 expression on CD14+ cells compared to healthy control (p=0.0001). This increased MFI of untreated VL cases was reduced 1.92-fold in successfully treated cases (p=0.0001). This observation was also accorded by mRNA expression for LFA-3 in monocytes of corresponding samples. The expression of LFA-3 was also observed influenced by L. donovani load in splenic aspirates, as it was 1.71-fold elevated in patients with Ld grade ⩾3+ compared to patients with ⩽2+ Ld grade (p=0.0121). To evaluate the possibility that L. donovani utilize LFA-3 mediated evasion pathway in human visceral leishmaniasis; in vitro experiments were performed for measurement of pathogenic cytokine IL-10 and Foxp3 mRNA expression. The IL-10 production and Foxp3 expression in peripheral blood mononuclear cells from VL subjects were observed regulated significantly (p=0.0131 and 0.0436 when compared with untreated samples) in presence of an antagonist to LFA-3. This study recommends further investigations to strengthen the pathogenic and prognostic significance of LFA-3 in visceral leishmaniasis.

Increase ICAM-1 and LFA-1 expression by cerebrospinal fluid of subarachnoid hemorrhage patients: Involvement of TNF-α

Subarachnoid hemorrhage (SAH) is a frequent occurrence in cerebrovascular accidents, and inflammation occurs in the subarachnoid space after SAH. Arachnoid cells have the capability to present antigens and active T-lymphocytes after stimulation by cerebrospinal fluid (CSF). However, the effect of CSF on T-lymphocytes and arachnoid cell adhesion was not clearly understood. In this study, we used ELISA to detected tumor necrosis factor-α (TNF-α) content in CSF of SAH patients. CSF or recombinant TNF-α were applied on arachnoid cells and T-lymphoctes, and RT-PCR and western blotting were performed to determine the expression of intercellular adhesion molecule-1 (ICAM-1) in arachnoid cells and Lymphocyte Function-Associated Antigen-1 (LFA-1) in T-lymphocytes, respectively. Meanwhile, the Matrix Metal Proteinase-9 (MMP-9) expression in these cells was also determined. We found that the content of TNF-α in the CSF was significantly increased in the CSF of SAH patients (from 22±8pg/mL of healthy people to 436–450pg/mL of SAH patients). Treatement with CSF could increase the expression of ICAM-1in arachnoid cells and that of LFA-1 in T-lymphocytes, mainly through the increased levels of TNF-α. We also found that the co-culture of arachnoid cells and T-lymphocytes increased the expression of MMP-9 in both cells through the interaction of ICAM-1 of and LFA-1. All of these results suggested that arachnoid cells are involved in the T-lymphocytes invasion in the subarachnoid space after SAH.

Suppression of LFA-1 Expression by Spermine Is Associated with Enhanced Methylation of ITGAL, the LFA-1 Promoter Area

Spermine and spermidine, natural polyamines, suppress lymphocyte function-associated antigen 1 (LFA-1) expression and its associated cellular functions through mechanisms that remain unknown. Inhibition of ornithine decarboxylase, which is required for polyamine synthesis, in Jurkat cells by 3 mM D,L-alpha-difluoromethylornithine hydrochloride (DFMO) significantly decreased spermine and spermidine concentrations and was associated with decreased DNA methyltransferase (Dnmt) activity, enhanced demethylation of the LFA-1 gene (ITGAL) promoter area, and increased CD11a expression. Supplementation with extracellular spermine (500 µM) of cells pretreated with DFMO significantly increased polyamine concentrations, increased Dnmt activity, enhanced methylation of the ITGAL promoter, and decreased CD11a expression. It has been shown that changes in intracellular polyamine concentrations affect activities of -adenosyl-L-methionine-decaroboxylase, and, as a result, affect concentrations of the methyl group donor, S-adenosylmethionine (SAM), and of the competitive Dnmt inhibitor, decarboxylated SAM. Additional treatments designed to increase the amount of SAM and decrease the amount of decarboxylated SAM–such as treatment with methylglyoxal bis-guanylhydrazone (an inhibitor of S-adenosyl-L-methionine-decaroboxylase) and SAM supplementation–successfully decreased CD11a expression. Western blot analyses revealed that neither DFMO nor spermine supplementation affected the amount of active Ras-proximate-1, a member of the Ras superfamily of small GTPases and a key protein for regulation of CD11a expression. The results of this study suggest that polyamine-induced suppression of LFA-1 expression occurs via enhanced methylation of ITGAL.