A live imaging cell motility screen identifies prostaglandin E2 as a T cell stop signal antagonist

Interaction between microglial cells and CD1C+ B dendritic cells leads to CD8+ T cells depletion during the early stages of renal clear cell carcinoma

Renal clear cell carcinoma (RCC) is a type of malignant tumor, which, in addition to surgical resection, radiotherapy, and chemotherapy, has been widely treated through immunotherapy recently. However, the influence of the tumor microenvironment and the infiltrating immune cells within it on immunotherapy remains unclear. It is imperative to study the interactions between various immune cells of RCC. The scRNA-seq dataset from GEO's database was used to analyze the immune cells present in tumor tissue and peripheral blood samples. Through quality control, clustering, and identification, the types and proportions of infiltrating immune cells were determined. The cellular differences were determined, and gene expression levels of the differentially present cells were investigated. A protein-protein interaction network analysis was performed using string. KEGG and GO analyses were performed to investigate abnormal activities. The microglia marker CD68 and CD1C+ B dendritic cells marker CD11C were detected using multiplex immunofluorescence staining. Many depleted CD8+ T cells (exhausted CD8+ T cells) appeared in tumor tissues as well as microglia. CD1C+ B dendritic cells did not infiltrate tumor tissues. HSPA1A was correlated with DNAJB1 in microglia. Compared with Paracancer tissues, microglia increased while CD1C+ B dendritic cells decreased in pathological stages I and I-II in cancerous tissues. An altered tumor microenvironment caused by increases in microglia in RCC in the early stage resulted in an inability of CD1C+ B dendritic cells to infiltrate, resulting in CD8+ T cells being unable to receive the antigens presented by them, and in turn being depleted in large quantities.

The dual role of Nrf2 in melanoma: a systematic review

Melanoma is the most lethal type of skin cancer that originates from the malignant transformation of melanocytes. Although novel treatments have improved patient survival in melanoma, the overall prognosis remains poor. To improve current therapies and patients outcome, it is necessary to identify the influential elements in the development and progression of melanoma.Due to UV exposure and melanin synthesis, the melanocytic lineage seems to have a higher rate of ROS (reactive oxygen species) formation. Melanoma has been linked to an increased oxidative state, and all facets of melanoma pathophysiology rely on redox biology. Several redox-modulating pathways have arisen to resist oxidative stress. One of which, the Nrf2 (nuclear factor erythroid 2-related factor 2), has been recognized as a master regulator of cellular response to oxidative or electrophilic challenges. The activation of Nrf2 signaling causes a wide range of antioxidant and detoxification enzyme genes to be expressed. As a result, this transcription factor has lately received a lot of interest as a possible cancer treatment target.On the other hand, Nrf2 has been found to have a variety of activities in addition to its antioxidant abilities, constant Nrf2 activation in malignant cells may accelerate metastasis and chemoresistance. Hence, based on the cell type and context, Nrf2 has different roles in either preventing or promoting cancer. In this study, we aimed to systematically review all the studies discussing the function of Nrf2 in melanoma and the factors determining its alteration.

Adenosine A2a Receptor Antagonism Restores Additive Cytotoxicity by Cytotoxic T Cells in Metabolically Perturbed Tumors

Cytotoxic T lymphocytes (CTL) are antigen-specific effector cells with the ability to eradicate cancer cells in a contact-dependent manner. Metabolic perturbation compromises the CTL effector response in tumor subregions, resulting in failed cancer cell elimination despite the infiltration of tumor-specific CTLs. Restoring the functionality of these tumor-infiltrating CTLs is key to improve immunotherapy. Extracellular adenosine is an immunosuppressive metabolite produced within the tumor microenvironment. Here, by applying single-cell reporter strategies in 3D collagen cocultures in vitro and progressing tumors in vivo, we show that adenosine weakens one-to-one pairing of activated effector CTLs with target cells, thereby dampening serial cytotoxic hit delivery and cumulative death induction. Adenosine also severely compromised CTL effector restimulation and expansion. Antagonization of adenosine A2a receptor (ADORA2a) signaling stabilized and prolonged CTL-target cell conjugation and accelerated lethal hit delivery by both individual contacts and CTL swarms. Because adenosine signaling is a near-constitutive confounding parameter in metabolically perturbed tumors, ADORA2a targeting represents an orthogonal adjuvant strategy to enhance immunotherapy efficacy.

Human integrin α10β1-selected mesenchymal stem cells home to cartilage defects in the rabbit knee and assume a chondrocyte-like phenotype

BACKGROUND

Mesenchymal stem cells (MSCs) have shown promising results in stimulating cartilage repair and in the treatment of osteoarthritis (OA). However, the fate of the MSCs after intra-articular injection and their role in cartilage regeneration is not clear. To address these questions, this study investigated (1) homing of labeled human adipose tissue derived integrin α10β1-selected MSCs (integrin α10-MSCs) to a cartilage defect in a rabbit model and (2) the ability of the integrin α10-MSCs to differentiate to chondrocytes and to produce cartilage matrix molecules in vivo.

DESIGN

Integrin α10-MSCs were labeled with superparamagnetic iron oxide nanoparticles (SPIONs) co-conjugated with Rhodamine B to allow visualization by both MRI and fluorescence microscopy. A cartilage defect was created in the articular cartilage of the intertrochlear groove of the femur of rabbits. Seven days post-surgery, labeled integrin α10-MSCs or vehicle were injected into the joint. Migration and distribution of the SPION-labeled integrin α10-MSCs was evaluated by high-field 9.4 T MRI up to 10 days after injection. Tissue sections from the repair tissue in the defects were examined by fluorescence microscopy.

RESULTS

In vitro characterization of the labeled integrin α10-MSCs demonstrated maintained viability, proliferation rate and trilineage differentiation capacity compared to unlabeled MSCs. In vivo MRI analysis detected the labeled integrin α10-MSCs in the cartilage defects at all time points from 12 h after injection until day 10 with a peak concentration between day 1 and 4 after injection. The labeled MSCs were also detected lining the synovial membrane at the early time points. Fluorescence analysis confirmed the presence of the labeled integrin α10-MSCs in all layers of the cartilage repair tissue and showed co-localization between the labeled cells and the specific cartilage molecules aggrecan and collagen type II indicating in vivo differentiation of the MSCs to chondrocyte-like cells. No adverse effects of the α10-MSC treatment were detected during the study period.

CONCLUSION

Our results demonstrated migration and homing of human integrin α10β1-selected MSCs to cartilage defects in the rabbit knee after intra-articular administration as well as chondrogenic differentiation of the MSCs in the regenerated cartilage tissue.

Human Oral Epithelial Cells Suppress T Cell Function via Prostaglandin E2 Secretion

The oral mucosa is constantly exposed to a plethora of stimuli including food antigens, commensal microbiota and pathogens, requiring distinct immune responses. We previously reported that human oral epithelial cells (OECs) suppress immune responses to bacteria, using H413 and TR146 OEC lines and primary OECs in co-culture with dendritic cells (DCs) and T cells (OEC-conditioned cells). OECs reduced DCs expression of CD80/CD86 and IL-12/TNFα release and impaired T cell activation. Here, we further evaluated the immunosuppression by these OECs and investigated the underlying mechanisms. OEC-conditioned DCs did not induce CD4 T cell polarization towards Treg, judging by the absence of FoxP3 expression. OECs also repressed T-bet/IFNγ expression in CD4 and CD8 T cells activated by DCs or anti-CD3/CD28 antibodies. This inhibition depended on OEC:T cell ratio and IFNγ repression occurred at the transcriptional level. Time-lapse experiments showed that OECs inhibited early steps of T cell activation, consistent with OECs inability to suppress T cells stimulated with PMA/ionomycin. Blocking CD40/CD40L, CD58/CD2 and PD-L1/PD-1 interactions with specific antibodies did not disrupt T cell suppression by OECs. However, preventing prostaglandin E2 (PGE2) synthesis or blocking PGE2 binding to the cognate EP2/EP4 receptors, restored IFNγ and TNFα production in OEC-conditioned T cells. Finally, treating OECs with poly(I:C), which simulates viral infections, limited T cell suppression. Overall, these results point to an inherent ability of OECs to suppress immune responses, which can nonetheless be eluded when OECs are under direct assault.

Small molecular drugs reshape tumor microenvironment to synergize with immunotherapy

Recently, immune checkpoint blockade (ICB), especially anti-programmed death 1 (anti-PD-1) and anti-programmed death-ligand 1 (anti-PD-L1) therapy, has become an increasingly appealing therapeutic strategy for cancer patients. However, only a small portion of patients responds to anti-PD treatment. Therefore, treatment strategies are urgently needed to reverse the ICB-resistant tumor microenvironment (TME). It has become clear that the TME has diminished innate sensing that is critical to activate adaptive immunity. In addition, tumor cells upregulate various immunosuppressive factors to diminish the immune response and resist immunotherapy. In this review, we briefly update the current small molecular drugs that could synergize with immunotherapy, especially anti-PD therapy. We will discuss the modes of action by those drugs including inducing innate sensing and limiting immunosuppressive factors in the TME.

Microglia in the Brain Tumor Microenvironment

Microglia are the brain resident phagocytes that act as the primary form of the immune defense in the central nervous system. These cells originate from primitive macrophages that arise from the yolk sac. Advances in imaging and single-cell RNA-seq technologies provided new insights into the complexity of microglia biology.Microglia play an essential role in the brain development and maintenance of brain homeostasis. They are also crucial in injury repair in the central nervous system. The tumor microenvironment is complex and includes neoplastic cells as well as varieties of host and infiltrating immune cells. Microglia are part of the glioma microenvironment and play a critical part in initiating and maintaining tumor growth and spread. Microglia can also act as effector cells in treatments against gliomas. In this chapter, we summarize the current knowledge of how and where microglia are generated. We also discuss their functions during brain development, injury repair, and homeostasis. Moreover, we discuss the role of microglia in the tumor microenvironment of gliomas and highlight their therapeutic implications.

NRF2-dependent stress defense in tumor antioxidant control and immune evasion

The transcription factor NRF2 is known as the master regulator of the oxidative stress response. Tumor entities presenting oncogenic activation of NRF2, such as lung adenocarcinoma, are associated with drug resistance, and accumulating evidence demonstrates its involvement in immune evasion. In other cancer types, the KEAP1/NRF2 pathway is not commonly mutated, but NRF2 is activated by other means such as radiation, oncogenic activity, cytokines, or other pro-oxidant triggers characteristic of the tumor niche. The obvious effect of stress-activated NRF2 is the protection from oxidative or electrophilic damage and the adaptation of the tumor metabolism to changing conditions. However, data from melanoma also reveal a role of NRF2 in modulating differentiation and suppressing anti-tumor immunity. This review summarizes the function of NRF2 in this tumor entity and discusses the implications for current tumor therapies.

The transcription factor NRF2 enhances melanoma malignancy by blocking differentiation and inducing COX2 expression

The transcription factor NRF2 is the major mediator of oxidative stress responses and is closely connected to therapy resistance in tumors harboring activating mutations in the NRF2 pathway. In melanoma, such mutations are rare, and it is unclear to what extent melanomas rely on NRF2. Here we show that NRF2 suppresses the activity of the melanocyte lineage marker MITF in melanoma, thereby reducing the expression of pigmentation markers. Intriguingly, we furthermore identified NRF2 as key regulator of immune-modulating genes, linking oxidative stress with the induction of cyclooxygenase 2 (COX2) in an ATF4-dependent manner. COX2 is critical for the secretion of prostaglandin E2 and was strongly induced by H₂O₂ or TNFα only in presence of NRF2. Induction of MITF and depletion of COX2 and PGE2 were also observed in NRF2-deleted melanoma cells in vivo. Furthermore, genes corresponding to the innate immune response such as RSAD2 and IFIH1 were strongly elevated in absence of NRF2 and coincided with immune evasion parameters in human melanoma datasets. Even in vitro, NRF2 activation or prostaglandin E2 supplementation blunted the induction of the innate immune response in melanoma cells. Transcriptome analyses from lung adenocarcinomas indicate that the observed link between NRF2 and the innate immune response is not restricted to melanoma.

A luciferase lysis assay reveals in vivo malignant cell sensitization by phosphoantigen prodrugs

Human Vγ9Vδ2 T cells respond to small phosphorus-containing compounds, often called phosphoantigens, which are now known to be intracellular ligands of the immune receptor butyrophilin 3A1 (BTN3A1). In order to compare the efficiency of butyrophilin ligands, we developed a luciferase-based lysis assay that measures the direct cytolysis by Vγ9Vδ2 T cells of luciferase-expressing K562 leukemia cells sensitized by phosphoantigen prodrugs. Our results show that the luciferase-based lysis assay allows in vitro and in vivo assessment of phosphoantigen activity in a way that does not require the extensive processing of flow cytometry or ELISA based approaches. In cellular assays, the structure activity relationships of phosphoantigen prodrugs correlate with ELISA-based activation assays, though phosphoantigen induced target cell lysis occurs at lower concentrations relative to T cell interferon γ production measured by ELISA. In mice dosed with phosphoantigens, a racemic aryl phosphonamidate prodrug, methyl 2-[[[(E)-5-hydroxy-4-methyl-pent-3-enyl]-(1-naphthyloxy)phosphoryl]amino]acetate (1-Nap/GlyOMe C-HMBP, 5), sensitized subcutaneous K562 tumors within minutes, and this effect was maintained at least four hours after treatment. In vivo activity of compound 5 was stronger than that of an equivalent dose of zoledronate. This luciferase lysis assay can be used for evaluation of phosphoantigens due to its time efficiency, high sensitivity, and in vivo compatibility and demonstrates rapid in vitro and in vivo sensitization of tumor cells by phosphoantigen prodrugs.

Effect of Bone Morphogenetic Protein 6 on Immunomodulatory Functions of Salivary Gland-Derived Mesenchymal Stem Cells in Sjögren's Syndrome

Sjögren's syndrome (SS) is characterized by autoimmune activation and loss of function in the salivary glands. Recent studies reported that bone morphogenetic protein 6 (BMP6), which is a member of transforming growth factor beta (TGF-β) superfamily, was highly expressed in SS patients. To investigate the role of BMP6 in SS, we treated the salivary gland-derived mesenchymal stem cells (SGMSCs) with BMP6 and found that BMP6 could impair immunomodulatory properties of normal SGMSCs by downregulating the Prostaglandin E2 synthase through DNA-binding protein inhibitor-1. Neutralizing the BMP6 could significantly restore the SGMSC's immunoregulatory function in vitro and delay the SS disease activity in vivo. In conclusion, BMP6 could not only affect the secreting function of epithelial cells in the salivary gland but also influence the immunomodulatory properties of SGMSCs, which may trigger or enhance the autoimmune reflection in SS.

The Role of Tumor Necrosis Factor α in the Biology of Uterine Fibroids and the Related Symptoms

Uterine fibroids (UFs) are the most common benign tumors of the female genital tract. The incidence of UFs has been estimated at 25⁻80% depending on selected population. The pathophysiology of UFs remains poorly understood. The transformation of smooth muscle cells of the uterus into abnormal, immortal cells, capable of clonal division, is the main component of all pathways leading to UF tumor formation and tumor necrosis factor α (TNF-α) is believed to be one of the key factors in this field. TNF-α is a cell signaling protein involved in systemic inflammation and is one of the cytokines responsible for the acute phase reaction. This publication presents current data about the role of tumor necrosis factor α in the biology of UFs and the related symptoms. TNF-α is an extremely important cytokine associated with the biology of UFs, UF-related symptoms and complaints. Its concentration has been proven to be elevated in women with clinically symptomatic UFs. The presented data suggest the presence of an "inflammation-like" state in women with UFs where TNF-α is a potent inflammation inducer. The origin of numerous symptoms reported by women with UFs can be traced back to the TNF-α influence. Nevertheless, our knowledge on this subject remains limited and TNF-α dependent pathways in UF pathophysiology should be investigated further.

The Relationship of COX-2 Gene Polymorphisms and Susceptibility to Kawasaki Disease in Chinese Population

BACKGROUND

Kawasaki disease (KD) is an acute systemic vasculitis that predominantly affects children, and it can result in coronary artery lesions. Cyclooxygenase-2 (COX-2) is involved in the conversion of arachidonic acid to prostaglandin H2, an important precursor of several prostaglandins. The aim of this study was to examine the association between COX-2 gene polymorphisms and susceptibility to KD.

METHODS

A total of 276 subjects (136 KD and 140 controls) were recruited. The analysis of two single nucleotide polymorphisms rs689466 (-1195G/A) and rs20417 (-765G/C) was respectively detected with polymerase chain reaction sequence-based typing methods.

RESULTS

Polymorphisms of rs689466 were significantly different between the normal controls and KD patients (χ² = 6.070 and 5.435, both p < 0.05). The frequencies of AA genotype and A allele of rs689466 in Kawasaki disease group were higher than that of control group (χ² = 4.832, p = 0.028, OR = 1.832, 95%CI = 1.064-3.124; χ² = 5.435, p = 0.028, OR = 1.491, 95%CI = 1.065-2.088).

CONCLUSION

This study provides the first evidence supporting an association between COX-2 gene polymorphisms and susceptibility of KD. The AA genotype and A allele of rs689466 confer predisposing factors to KD.

Immunological Tolerance and Function: Associations Between Intestinal Bacteria, Probiotics, Prebiotics, and Phages

Post-birth there is a bacterial assault on all mucosal surfaces. The intestinal microbiome is an important participant in health and disease. The pattern of composition and concentration of the intestinal microbiome varies greatly. Therefore, achieving immunological tolerance in the first 3-4 years of life is critical for maintaining health throughout a lifetime. Probiotic bacteria are organisms that afford beneficial health effects to the host and in certain instances may protect against the development of disease. The potential benefits of modifying the composition of the intestinal microbial cohort for therapeutic benefit is evident in the use in high risks groups such as premature infants, children receiving antibiotics, rotavirus infections in non-vaccinated children and traveler's diarrhea in adults. Probiotics and prebiotics are postulated to have immunomodulating capabilities by influencing the intestinal microbial cohort and dampening the activity of pathobiont intestinal microbes, such as Klebsiella pneumonia and Clostridia perfringens. Lactobacilli and Bifidobacteria are examples of probiotics found in the large intestine and so far, the benefits afforded to probiotics have varied in efficacy. Most likely the efficacy of probiotic bacteria has a multifactorial dependency, namely on a number of factors that include agents used, the dose, the pattern of dosing, and the characteristics of the host and the underlying luminal microbial environment and the activity of bacteriophages. Bacteriophages, are small viruses that infect and lyse intestinal bacteria. As such it can be posited that these viruses display an effective local protective control mechanism for the intestinal barrier against commensal pathobionts that indirectly may assist the host in controlling bacterial concentrations in the gut. A co-operative activity may be envisaged between the intestinal epithelia, mucosal immunity and the activity of bacteriophages to eliminate pathobiots, highlighting the potential role of bacteriophages in assisting with maintaining intestinal homeostasis. Hence bacteriophage local control of inflammation and immune responses may be an additional immunological defense mechanism that exploits bacteriophage-mucin glycoprotein interactions that controls bacterial diversity and abundance in the mucin layers of the gut. Moreover, and importantly the efficacy of probiotics may be dependent on the symbiotic incorporation of prebiotics, and the abundance and diversity of the intestinal microbiome encountered. The virome may be an important factor that determines the efficacy of some probiotic formulations.

Prostaglandin E2 Stimulates the Expansion of Regulatory Hematopoietic Stem and Progenitor Cells in Type 1 Diabetes

Hematopoietic stem and progenitor cells (HSPCs) are multipotent stem cells that have been harnessed as a curative therapy for patients with hematological malignancies. Notably, the discovery that HSPCs are endowed with immunoregulatory properties suggests that HSPC-based therapeutic approaches may be used to treat autoimmune diseases. Indeed, infusion with HSPCs has shown promising results in the treatment of type 1 diabetes (T1D) and remains the only “experimental therapy” that has achieved a satisfactory rate of remission (nearly 60%) in T1D. Patients with newly diagnosed T1D have been successfully reverted to normoglycemia by administration of autologous HSPCs in association with a non-myeloablative immunosuppressive regimen. However, this approach is hampered by a high incidence of adverse effects linked to immunosuppression. Herein, we report that while the use of autologous HSPCs is capable of improving C-peptide production in patients with T1D, ex vivo modulation of HSPCs with prostaglandins (PGs) increases their immunoregulatory properties by upregulating expression of the immune checkpoint-signaling molecule PD-L1. Surprisingly, CXCR4 was upregulated as well, which could enhance HSPC trafficking toward the inflamed pancreatic zone. When tested in murine and human in vitro autoimmune assays, PG-modulated HSPCs were shown to abrogate the autoreactive T cell response. The use of PG-modulated HSPCs may thus provide an attractive and novel treatment of autoimmune diabetes.

Detrimental Influence of Alveolar Macrophages on Protective Humoral Immunity during Francisella tularensis SchuS4 Pulmonary Infection

Opsonizing antibody is a critical component of the host protective immune response against many respiratory pathogens. However, the role of antibodies in protection against pulmonary infection with highly virulent Francisella tularensis strain SchuS4 is unclear, and the mechanism that allows F. tularensis to evade antibody-mediated bacterial clearance is not fully understood. We have now found that depletion of alveolar macrophages reveals an otherwise cryptic protective effect of opsonizing antibody. While antibody opsonization alone failed to confer any survival benefit against SchuS4 lung infection, significant protection was observed when mice were depleted of alveolar macrophages prior to infection. Blood immune signature analyses and bacterial burden measurements indicated that the treatment regimen blocked establishment of productive, systemic infection. In addition, protection was found to be dependent upon neutrophils. The results show for the first time a protective effect of opsonizing antibodies against highly virulent F. tularensis SchuS4 pulmonary infection through depletion of alveolar macrophages, the primary bacterial reservoir, and prevention of systemic dissemination. These findings have important implications for the potential use of therapeutic antibodies against intracellular pathogens that may escape clearance by residing within mucosal macrophages.

Anti-inflammatory effects of embelin in A549 cells and human asthmatic airway epithelial tissues

OBJECTIVE

Allergic asthma is the most common type in asthma, which is defined as a chronic inflammatory disease of the lung. In this study, we investigated whether embelin (Emb), the major component of Ardisia japonica BL. (AJB), exhibits anti-inflammatory effects on allergic asthma via inhibition of NF-κB activity using A549 cells and asthmatic airway epithelial tissues.

METHODS

Inflammation was induced in A549 cells, a human airway epithelial cell line, by IL-1β (10 ng/ml) treatment for 4 h. The effects of Emb on NF-κB activity and COX-2 protein expression in inflamed airway epithelial cells and human asthmatic airway epithelial tissues were analyzed via western blot. The secretion levels of NF-κB-mediated cytokines/chemokines, including IL-4, 6, 9, 13, TNF-α and eotaxin, were measured by a multiplex assay.

RESULTS

Emb significantly blocked NF-κB activity in IL-1β-treated A549 cells and human asthmatic airway epithelial tissues. COX-2 expression was also reduced in both IL-1β-treated A549 cells and asthmatic tissues Emb application. Emb significantly reduced the secretion of IL-4, IL-6 and eotaxin in human asthmatic airway epithelial tissues by inhibiting activity of NF-κB.

CONCLUSIONS

The results of this study suggest that Emb may be used as an anti-inflammatory agent via inhibition of NF-κB and related cytokines.

Prostaglandin E2 promotes human CD34+ cells homing through EP2 and EP4 in vitro

Recently, certain studies have demonstrated in vitro that prostaglandin E2 (PGE2) promotes human cluster of differentiation (CD)34⁺ cell homing. However, the sub-type receptors activated by PGE2 are unknown, as the PGE2 receptor EP1-4 subtypes (EP1-4) are expressed on the membrane of human CD34⁺ cells. Based on the above, the present study aimed to screen the receptor subtype activity by PGE2 to promote human CD34⁺ cell homing. It was observed that human CD34⁺ cells expressed the four PGE2 sub-receptors, particularly EP2 and 4. PGE2 increased EP2 and 4 mRNA expression significantly, while EP1 and 3 mRNA exhibited no significant alteration. PGE2, EP2 agonist (EP2A), and EP4A upregulated C-X-C chemokine receptor 4 mRNA and protein expression in human CD34⁺ cells, and promoted stromal cell-derived factor 1α (SDF-1α) expression in bone marrow mesenchymal stem cells (BMMSCs). These phenomena were inhibited by the associated receptor antagonists. PGE2, EP2A, and EP4A facilitated human CD34⁺ cell migration towards SDF-1α and BMMSCs. The results of the present study suggested that PGE2 promoted human CD34⁺ cell homing through EP2 and 4 receptors in vitro.

hrHPV E5 oncoprotein: immune evasion and related immunotherapies

The immune response is a key factor in the fight against HPV infection and related cancers, and thus, HPV is able to promote immune evasion through the expression of oncogenes. In particular, the E5 oncogene is responsible for modulation of several immune mechanisms, including antigen presentation and inflammatory pathways. Moreover, E5 was suggested as a promising therapeutic target, since there is still no effective medical therapy for the treatment of HPV-related pre-neoplasia and cancer. Indeed, several studies have shown good prospective for E5 immunotherapy, suggesting that it could be applied for the treatment of pre-cancerous lesions. Thus, insofar as the majority of cervical, oropharyngeal and anal cancers are caused by high-risk HPV (hrHPV), mainly by HPV16, the aim of this review is to discuss the immune pathways interfered by E5 oncoprotein of hrHPV highlighting the various aspects of the potential immunotherapeutic approaches.

Anti-Inflammatory Effects of Ginsenoside Rg3 via NF-κB Pathway in A549 Cells and Human Asthmatic Lung Tissue

Objective. There is limited information of the anti-inflammatory effects of Rg3 on inflamed lung cells and tissues. Therefore, we confirmed the anti-inflammatory mechanism of ginsenoside Rg3 in inflamed human airway epithelial cells (A549) and tissues whether Rg3 regulates nuclear factor kappa B (NF-κB) activity. Methods. To induce the inflammation, IL-1β (10 ng/ml) was treated to A549 cells for 4 h. The effects of Rg3 on NF-κB activity and COX-2 expression were evaluated by western blotting analysis in both IL-1β-induced inflamed A549 cell and human asthmatic airway epithelial tissues. Using multiplex cytokines assay, the secretion levels of NF-κB-mediated cytokines/chemokines were measured. Result. Rg3 showed the significant inhibition of NF-κB activity thereby reduced COX-2 expression was determined in both IL-1β-induced inflamed A549 cell and human asthmatic airway epithelial tissues. In addition, among NF-κB-mediated cytokines, the secretion levels of IL-4, TNF-α, and eotaxin were significantly decreased by Rg3 in asthma tissues. Even though there was no significant difference, IL-6, IL-9, and IL-13 secretion showed a lower tendency compared to saline-treated human asthmatic airway epithelial tissues. Conclusion. The results from this study demonstrate the potential of Rg3 as an anti-inflammatory agent through regulating NF-κB activity and reducing the secretion of NF-κB-mediated cytokines/chemokines.

Plasma Prostaglandin E2 Levels Correlated with the Prevention of Intravenous Immunoglobulin Resistance and Coronary Artery Lesions Formation via CD40L in Kawasaki Disease

BACKGROUND

A form of systemic vasculitis, Kawasaki disease (KD) occurs most frequently in children under the age of five years old. Previous studies have found that Prostaglandin E2 (PGE2) correlates with KD, although the related mechanisms are still unknown. CD40L may also be a marker of vasculitis in KD, so this study focuses on PGE2 and CD40L expression in KD.

MATERIALS AND METHODS

This study consisted of a total of 144 KD patients, whose intravenous immunoglobulin (IVIG)/coronary arterial lesion (CAL) formation resistance was evaluated. PGE2 levels were evaluated in vitro to study the effect of CD40L on CD4+ T lymphocytes.

RESULTS

PGE2 levels significantly increased after IVIG treatment (p<0.05), especially in patients who responded to initial IVIG treatment (p = 0.004) and for patients without CAL formation (p = 0.016). Furthermore, an in vitro study revealed that IVIG acted as a trigger for PGE2 expression in the acute-stage mononuclear cells of KD patients. According to our findings, both IVIG and PGE2 can impede surface CD40L expressions on CD4+ T lymphocytes (p<0.05).

CONCLUSIONS

The results of this study are among the first to find that plasma PGE2 is correlated with the prevention of IVIG resistance and CAL formation through CD40L in KD.

Induction of regulatory T cells: A role for probiotics and prebiotics to suppress autoimmunity

Regulatory T cells (Tregs) are comprised of a heterogeneous population of cells that play a vital role in suppressing inflammation and maintaining immune tolerance. Given the crucial role of Tregs in maintaining immune homeostasis, it is probably not surprising that many microbial species and their metabolites have the potential to induce Tregs. There is now great interest in the therapeutic potential of probiotics and prebiotics based strategies for a range of autoimmune disorders. This review will summarise recent findings concerning the role of probiotics and prebiotics in induction of Tregs to ameliorate the autoimmune conditions. In addition, the article is focused to explain the different mechanisms of Treg induction and function by these probiotics and prebiotics, based on the available studies till date. The article further proposes that induction of Tregs by probiotics and prebiotics could lead to the development of new therapeutic approach towards curbing the autoimmune response and as an alternative to detrimental immunosuppressive drugs.

Polyunsaturated Fatty Acid-derived lipid mediators and T cell function

Fatty acids are involved in T cell biology both as nutrients important for energy production as well as signaling molecules. In particular, polyunsaturated fatty acids are known to exhibit a range of immunomodulatory properties that progress through T cell mediated events, although the molecular mechanisms of these actions have not yet been fully elucidated. Some of these immune activities are linked to polyunsaturated fatty acid-induced alteration of the composition of cellular membranes and the consequent changes in signaling pathways linked to membrane raft-associated proteins. However, significant aspects of the polyunsaturated fatty acid bioactivities are mediated through their transformation to specific lipid mediators, products of cyclooxygenase, lipoxygenase, or cytochrome P450 enzymatic reactions. Resulting bioactive metabolites including prostaglandins, leukotrienes, and endocannabinoids are produced by and/or act upon T leukocytes through cell surface receptors and have been shown to alter T cell activation and differentiation, proliferation, cytokine production, motility, and homing events. Detailed appreciation of the mode of action of these lipids presents opportunities for the design and development of therapeutic strategies aimed at regulating T cell function.

The focal adhesion kinase inhibitor PF-562,271 impairs primary CD4+ T cell activation

The focal adhesion kinase inhibitor, PF-562,271, is currently in clinical development for cancer, however it is not known how PF-562,271 affects T cell function. Here, we demonstrate inhibitory effects of PF-562,271 on the activation of primary human and mouse T cells. PF-562,271 inhibits T cell receptor signaling-induced T cell adhesion to intercellular adhesion molecule-1 and T cell interactions with antigen-presenting cells. An additional focal adhesion kinase inhibitor, PF-573,228, and genetic depletion of focal adhesion kinase also impair T cell conjugation with antigen-presenting cells. PF-562,271 blocks phosphorylation of the signaling molecules zeta chain associate protein of 70 kDa, linker of activated T cells, and extracellular signal-regulated kinase, and impairs T cell proliferation. The effects observed on T cell proliferation cannot solely be attributed to focal adhesion kinase inhibition, as genetic depletion did not alter proliferation. The effect of PF-562,271 on T cell proliferation is not rescued when proximal T cell receptor signaling is bypassed by stimulation with phorbol-12-myristate-13-acetate and ionomycin. Taken together, our findings demonstrate that focal adhesion kinase regulates integrin-mediated T cell adhesion following T cell receptor activation. Moreover, our findings suggest that PF-562,271 may have immunomodulatory effects that could impact its therapeutic applications.

Eicosanoid modulation by the short-chain fatty acid n-butyrate in human monocytes

n-Butyrate deriving from bacterial fermentation in the mammalian intestine is a key determinant in gastrointestinal homeostasis. We examined the effects of this short-chain fatty acid and Toll-like receptor 2 (TLR) and TLR4 engagement on inflammatory/immunity-associated genes, cyclo-oxygenases (COXs), prostaglandins (PGs) and leukotrienes (LTs) in human monocytes. Before RNA isolation, freshly isolated human monocytes were co-incubated for different time-points with 1 mm n-butyrate alone or in combination with bacterial stimuli. Based on a knowledge-driven approach, a signature of 180 immunity/inflammation-associated genes was picked and real-time PCR analysis was performed. Pathway analysis was carried out using a web-based database analysing program. Based on these gene expression studies the findings were evaluated at the protein/mediator level by Western blot analysis, FACS and ELISA. Following co-incubation with n-butyrate and lipopolysaccharide, key enzymes of the eicosanoid pathway, like PTGS2 (COX-2), TXS, ALOX5, LTA4H and LTC4S, were significantly up-regulated compared with stimulation with lipopolysaccharide alone. Furthermore, release of the lipid mediators PGE(2), 15d-PGJ(2), LTB(4) and thromboxane B(2) was increased by n-butyrate. Regarding signalling, n-butyrate had no additional effect on mitogen-activated protein kinase and interfered differently with early and late phases of nuclear factor-κB signalling. Our results suggest that among many other mediators of eicosanoid signalling n-butyrate massively induces PGE(2) production by increasing the expression of PTGS2 (COX-2) in monocytes following TLR4 and TLR2 activation and induces secretion of LTB(4) and thromboxane B(2). This underscores the role of n-butyrate as a crucial mediator of gut-specific immunity.