Stimulatory and inhibitory effects of interleukin (IL)-4 and IL-13 on the production of cytokines by human peripheral blood mononuclear cells: priming for IL-12 and tumor necrosis factor alpha production

Establishment of a Human Immunocompetent 3D Tissue Model to Enable the Long-Term Examination of Biofilm-Tissue Interactions

Different studies suggest an impact of biofilms on carcinogenic lesion formation in varying human tissues. However, the mechanisms of cancer formation are difficult to examine in vivo as well as in vitro. Cell culture approaches, in most cases, are unable to keep a bacterial steady state without any overgrowth. In our approach, we aimed to develop an immunocompetent 3D tissue model which can mitigate bacterial outgrowth. We established a three-dimensional (3D) co-culture of human primary fibroblasts with pre-differentiated THP-1-derived macrophages on an SIS-muc scaffold which was derived by decellularisation of a porcine intestine. After establishment, we exposed the tissue models to define the biofilms of the Pseudomonas spec. and Staphylococcus spec. cultivated on implant mesh material. After 3 days of incubation, the cell culture medium in models with M0 and M2 pre-differentiated macrophages presented a noticeable turbidity, while models with M1 macrophages presented no noticeable bacterial growth. These results were validated by optical density measurements and a streak test. Immunohistology and immunofluorescent staining of the tissue presented a positive impact of the M1 macrophages on the structural integrity of the tissue model. Furthermore, multiplex ELISA highlighted the increased release of inflammatory cytokines for all the three model types, suggesting the immunocompetence of the developed model. Overall, in this proof-of-principle study, we were able to mitigate bacterial overgrowth and prepared a first step for the development of more complex 3D tissue models to understand the impact of biofilms on carcinogenic lesion formation.

Resolving sepsis-induced immunoparalysis via trained immunity by targeting interleukin-4 to myeloid cells

Immunoparalysis is a compensatory and persistent anti-inflammatory response to trauma, sepsis or another serious insult, which increases the risk of opportunistic infections, morbidity and mortality. Here, we show that in cultured primary human monocytes, interleukin-4 (IL4) inhibits acute inflammation, while simultaneously inducing a long-lasting innate immune memory named trained immunity. To take advantage of this paradoxical IL4 feature in vivo, we developed a fusion protein of apolipoprotein A1 (apoA1) and IL4, which integrates into a lipid nanoparticle. In mice and non-human primates, an intravenously injected apoA1-IL4-embedding nanoparticle targets myeloid-cell-rich haematopoietic organs, in particular, the spleen and bone marrow. We subsequently demonstrate that IL4 nanotherapy resolved immunoparalysis in mice with lipopolysaccharide-induced hyperinflammation, as well as in ex vivo human sepsis models and in experimental endotoxemia. Our findings support the translational development of nanoparticle formulations of apoA1-IL4 for the treatment of patients with sepsis at risk of immunoparalysis-induced complications.

Different sensitivity to diet-induced hyperinsulinemia and hyperglycemia between mice with global or bone marrow-specific apoE receptor-2 deficiency

This study explored the role of apoE receptor-2 (apoER2), a unique member of the LDL receptor family proteins with a restricted tissue expression profile, in modulating diet-induced obesity and diabetes. Unlike wild-type mice and humans in which chronic feeding of a high-fat Western-type diet leads to obesity and the prediabetic state of hyperinsulinemia before hyperglycemia onset, the Lrp8-/- mice with global apoER2 deficiency displayed lower body weight and adiposity, slower development of hyperinsulinemia, but the accelerated onset of hyperglycemia. Despite their lower adiposity, adipose tissues in Western diet-fed Lrp8-/- mice were more inflamed compared with wild-type mice. Additional experiments revealed that the hyperglycemia observed in Western diet-fed Lrp8-/- mice was due to impaired glucose-induced insulin secretion, ultimately leading to hyperglycemia, adipocyte dysfunction, and inflammation upon chronic feeding of the Western diet. Interestingly, bone marrow-specific apoER2-deficient mice were not defective in insulin secretion, exhibiting increased adiposity and hyperinsulinemia compared with wild-type mice. Analysis of bone marrow-derived macrophages revealed that apoER2 deficiency impeded inflammation resolution with lower secretion of IFN-β and IL-10 in response to LPS stimulation of IL-4 primed cells. The apoER2-deficient macrophages also showed an increased level of disabled-2 (Dab2) as well as increased cell surface TLR4, suggesting that apoER2 participates in Dab2 regulation of TLR4 signaling. Taken together, these results showed that apoER2 deficiency in macrophages sustains diet-induced tissue inflammation and accelerates obesity and diabetes onset while apoER2 deficiency in other cell types contributes to hyperglycemia and inflammation via defective insulin secretion.

Effect of IL4 and IL10 on a human in vitro type 1 diabetes model

We defined the effect of the anti-inflammatory cytokines IL4 and IL10 on an in vitro model of human T1D. After preincubation with IL4 or IL10, human islet microtissues were co-cultured with PBMC and proinflammatory cytokines for a few hours or for multiple days to assess acute and chronic effects. This resulted in an immune attack with infiltration of T cells into the islet, a loss of beta cell endocrine function, and an upregulation of HLA-I on the beta cells. HLA-I upregulation was associated with infiltration of T cells and both HLA-I expression and infiltration were associated with impaired insulin secretion. Preincubation with IL4 or IL10 did not preserve beta cell function but decreased infiltration of T cells. Our data support the hypothesis that a loss of beta cell endocrine function mediates an increase in beta cell specific antigen presentation. IL4 and IL10 failed to preserve beta cell endocrine function.

Biomaterial-Based Therapeutic Approaches to Osteoarthritis and Cartilage Repair Through Macrophage Polarization

There is an ever-increasing clinical and socioeconomic burden associated with cartilage lesions & osteoarthritis (OA). Its progression, chondrocyte death & hypertrophy are all facilitated by inflamed synovium & joint environment. Due to their capacity to switch between pro- & anti-inflammatory phenotypes, macrophages are increasingly being recognized as a key player in the healing process, which has been largely overlooked in the past. A biomaterial's inertness has traditionally been a goal while developing them in order to reduce the likelihood of adverse reactions from the host organism. A better knowledge of how macrophages respond to implanted materials has made it feasible to determine the biomaterial architectural parameters that control the host response & aid in effective tissue integration. Thus, this review summarizes novel therapeutic techniques for avoiding OA or increasing cartilage repair & regeneration that might be developed using new technologies tuning macrophages into desirable functional phenotypes.

Interleukin-33 and thymic stromal lymphopoietin are primary cytokines involved in the Th1/Th2 inflammatory response in chronic secretory otitis media

Background:

T-helper (Th)1/Th2 inflammatory responses are responsible for secretory otitis media (SOM) development. However, the mechanisms underlying these immune responses remain unknown. This study aims to identify the primary cytokines that play essential roles in chronic SOM.

Methods:

Two groups were established for the present study: chronic SOM group ( n = 21) and control group ( n = 10). The middle ear effusion and serum samples of the expression cytokines (interleukin IL-2, IL-4, IL-5, IL-13, IL-17, IL-25, IL-33, interferon [IFN]-γ, thymic stromal lymphopoietin [TSLP], immunoglobulin IgE, and pepsins) were analyzed by enzyme-linked immunosorbent assay.

Results:

The levels of IL-4, IL-5, IL-13, IL-17, IL-25, IFN-γ, TLSP, pepsins, IL-2, and IL-33 (all, p < 0.001) were higher in middle ear effusion, when compared to those in serum, in chronic SOM group (non-paired sample). However, there was no significant difference in serum expression for those cytokines compared chronic SOM group and control group. The paired sample expression for IL-33 and TLSP (both, p = 0.046) were higher compared the effusion and serum in chronic SOM group.

Conclusions:

IL-33 produces inflammatory cytokines, such as IL-1b, IL-6, TNF-α, IL-10, IL-4, and TGF-β, which through nucleus into cytoplasm causing inflammatory responses. The present study revealed that IL-33 also produce IL-17, IL-4, IL-5, and IL-13 inflammatory factors, triggering an inflammatory response. Study reported that the combined stimulation of TSLP and IL-33 elicits an approximately 10-fold increase in cytokine production, when compared to the stimulation of IL-33 alone. This suggests that IL-33 and TLSP may be the primary cytokines involved in Th1/Th2 inflammatory responses in chronic SOM.

Th2 IL-4/IL-13 dual blockade with Dupilumab is linked to some Emergent Th17 type Diseases including seronegative arthritis, enthesitis/enthesopathy, but not humoral autoimmune diseases

Dupilumab, an IL-4/IL-13 receptor blocker, has been linked to emergent seronegative inflammatory arthritis and psoriasis that form part of the spondyloarthropathy (SpA) spectrum. We systematically investigated patterns of immune disorders including predominantly Th17- (SpA pattern), Th2-mediated disorders and humoral autoimmune pattern diseases, using VigiBase, the World Health Organization's (WHO) global pharmacovigilance of adverse drug reactions (ADRs). Several bioinformatics databases and repositories were mined to couple Dupilumab-related immune-pharmacovigilance with molecular cascades relevant to reported findings. 37,848 Dupilumab ADR cases were reported, with skin, eye, musculoskeletal systems most affected. Seronegative arthritis (OR 9.61) psoriasis (OR 1.48), enthesitis/enthesopathy (OR 12.65), and iridocyclitis (OR 3.77) were highly associated. However, Ankylosing Spondylitis and IBD were not conclusively associated. Overall, classic polygenic humorally-mediated autoimmune diseases such as RA and SLE were not associated with Dupilumab use. Pathway analysis identified several biological pathways potentially involved in Dupilumab-associated ADRs, including the fibroblast growth factor receptor (FGFR; in particular, FGFR2) pathway. miRNAs analysis revealed the potential involvement of hsa-miR-21-5p and hsa-miR-335-5p. In conclusion, IL-4/IL-13 blockers are not unexpectedly protective against humoral autoimmune diseases but dynamically skew immune responses towards some IL-23/IL-17 cytokine pathway-related diseases. A robust signal potentially towards degenerative related pathology in the eye and vasculature due to loss of IL-4/IL-13 tissue reparative homeostatic mechanisms emerged.

CD40-CD154: A perspective from type 2 immunity

The interaction between CD40 and CD154 (CD40 ligand) is central in immunology, participating in CD4⁺ T cell priming by dendritic cells (DC), CD4⁺ T cell help to B cells and classical macrophage activation by CD4⁺ T cells. However, its role in the Th2 side of immunology including helminth infection remains incompletely understood. Contrary to viral and bacterial stimuli, helminth products usually do not cause CD40 up-regulation in DC, and exogenous CD40 ligation drives Th2-biased systems towards Th1. On the other hand, CD40 and CD154 are necessary for induction of most Th2 responses. We attempt to reconcile these observations, mainly by proposing that (i) CD40 up-regulation in DC in Th2 systems is mostly induced by alarmins, (ii) the Th2 to Th1 shift induced by exogenous CD40 ligation is related to the capacity of such ligation to enhance IL-12 production by myeloid cells, and (iii) signals elicited by endogenous CD154 available in Th2 contexts and by exogenous CD40 ligation are probably different. We stress that CD40-CD154 is important beyond cognate cellular interactions. In such a context, we argue that the proliferation response of B-cells to IL-4 plus CD154 reflects a Th2-specific mechanism for polyclonal B-cell amplification and IgE production at infection sites. Finally, we argue that CD154 is a general immune activation signal across immune polarization including Th2, and propose that competition for CD154 at tissue sites may provide negative feedback on response induction at each site.

Myeloid Cell-Specific IL-4 Receptor Knockout Partially Protects from Adipose Tissue Inflammation

IL-4 receptor signaling is supposed to play a major role in anti-inflammatory polarization and proliferation of adipose tissue macrophages. In this study, we examined the metabolic and inflammatory phenotype of C57BL/6J mice (IIl4ra) with LysM-dependent knockout (IIl4ra ^Δmyel) of the IL-4 receptor α-chain (IL-4Rα), the mandatory signaling component of IL-4 and IL-13, on chow and high-fat diet. Lean IIl4ra ^Δmyel mice showed decreased insulin sensitivity, no divergent adipose tissue macrophage polarization, but an increased percentage of CD8⁺ T cells in visceral adipose tissue. After 20 wk of a high-fat diet, IIl4ra ^Δmyel mice exhibited higher glucose tolerance, no changes in the lymphocyte compartment and fewer M1 macrophages in visceral adipose tissue. In vivo adipose tissue macrophage proliferation measured by BrdU incorporation was unaffected by Il4ra knockout. Interestingly, we show that IL-4Rα signaling directly augmented Itgax (Cd11c) gene expression in bone marrow-derived macrophages and increased the amount of CD11c⁺ macrophages in adipose tissue explants. Myeloid cell-specific knockout of Il4ra deteriorated insulin sensitivity in lean mice but improved parameters of glucose homeostasis and partially protected from adipose tissue inflammation in obese mice. Hence, IL-4Rα signaling probably plays a minor role in maintaining the macrophage M2 population and proliferation rates in vivo. Moreover, our data indicate that IL-4 signaling plays a proinflammatory role in adipose tissue inflammation by directly upregulating CD11c on adipose tissue macrophages.

Mast cell-derived IL-13 downregulates IL-12 production by skin dendritic cells to inhibit the TH1 cell response to cutaneous antigen exposure

BACKGROUND

Atopic dermatitis (AD) is characterized by a skin barrier defect aggravated by mechanical injury inflicted by scratching, a T_H2 cell-dominated immune response, and susceptibility to viral skin infections that are normally restrained by a T_H1 cell response. The signals leading to a T_H2 cell-dominated immune response in AD are not completely understood.

OBJECTIVE

Our aim was to determine the role of IL-13 in initiation of the T_H cell response to cutaneously encountered antigens.

METHODS

Wild-type, Il13^-/-, Il1rl1^-/-, and Il4ra^-/- mice, as well as mice with selective deficiency of IL-13 in mast cells (MCs) were studied; in addition, dendritic cells (DCs) purified from the draining lymph nodes of tape-stripped and ovalbumin (OVA)-sensitized skin were examined for their ability to polarize naive OVA-TCR transgenic CD4⁺ T cells. Cytokine expression was examined by reverse-transcriptase quantitative PCR, intracellular flow cytometry, and ELISA. Contact hypersensitivity to dinitrofluorobenzene was examined.

RESULTS

Tape stripping caused IL-33-driven upregulation of Il13 expression by skin MCs. MC-derived IL-13 acted on DCs from draining lymph nodes of OVA-sensitized skin to selectively suppress their ability to polarize naive OVA-TCR transgenic CD4⁺ T cells into IFN-γ-secreting cells. MC-derived IL-13 inhibited the T_H1 cell response in contact hypersensitivity to dinitrofluorobenzene. IL-13 suppressed IL-12 production by mouse skin-derived DCs in vitro and in vivo. Scratching upregulated IL13 expression in human skin, and IL-13 suppressed the capacity of LPS-stimulated human skin DCs to express IL-12 and promote IFN-γ secretion by CD4⁺ T cells.

CONCLUSION

Release of IL-13 by cutaneous MCs in response to mechanical skin injury inhibits the T_H1 cell response to cutaneous antigen exposure in AD.

Over-expression of miR-223 induces M2 macrophage through glycolysis alteration and attenuates LPS-induced sepsis mouse model, the cell-based therapy in sepsis

The attenuation of hyper-inflammation in sepsis with the administration of anti-inflammatory macrophages is an interesting adjuvant therapy for sepsis. Because the induction of anti-inflammatory macrophages by microRNA (miR), a regulator of mRNA, has been mentioned, the exploration on miR-induced anti-inflammatory macrophages was performed. The over-expression of miR-223 and miR-146a in RAW264.7 induced M2 macrophage-polarization (anti-inflammatory macrophages) as evaluated by the enhanced expression of Arginase-1 and Fizz. However, miR-223 over-expressed cells demonstrated the more potent anti-inflammatory property against LPS stimulation as lesser iNOS expression, lower supernatant IL-6 and higher supernatant IL-10 compared with miR-146a over-expressed cells. Interestingly, LPS stimulation in miR-223 over-expressed cells, compared with LPS-stimulated control cells, demonstrated lower activity of glycolysis pathway and higher mitochondrial respiration, as evaluated by the extracellular flux analysis, and also down-regulated HIF-1α, an important enzyme of glycolysis pathway. In addition, the administration of miR-223 over-expressed macrophages with IL-4 pre-conditioning, but not IL-4 stimulated control cells, attenuated sepsis severity in LPS injected mice as evaluated by serum creatinine, liver enzymes, lung histology and serum cytokines. In conclusion, miR-223 interfered with the glycolysis pathway through the down-regulation of HIF-1α, resulting in the anti-inflammatory status. The over-expression of miR-223 in macrophages prevented the conversion into M1 macrophage polarization after LPS stimulation. The administration of miR-223 over-expressed macrophages, with IL-4 preconditioning, attenuated sepsis severity in LPS model. Hence, a proof of concept in the induction of anti-inflammatory macrophages through the cell-energy interference for sepsis treatment was proposed as a basis of cell-based therapy in sepsis.

Anti-inflammatory effects of interleukin-4 on intervertebral disc cells

BACKGROUND CONTEXT

Inflammation has been associated with a number of pathological conditions including intervertebral disc (IVD) degeneration, increased risks of low back pain and other spinal diseases. Downregulating disc inflammation may be a strategy to reduce degeneration and more importantly back pain. Interleukin (IL)-4 was first discovered as a T-cell secreted factor that enhanced the proliferation of anti-IgM stimulated B cells and is now known as a cytokine that can stimulate cell proliferation and differentiation, tissue regeneration and neurological functions. IL-4 has been shown to be effective in inhibiting inflammatory pathways in chondrocytes. Immunohistochemical studies have shown that disc tissues are immunopositive for IL-4 receptor α (IL-4Rα) and IL-4. Yet, the roles of IL-4 and IL-4R in disc biology remain unknown.

PURPOSE

The purpose of this study is to understand the roles of IL-4 and IL-4Rα in IVDs and to determine if IL-4 can function to inhibit inflammation in IVD cells.

STUDY DESIGN/SETTING

In vitro experiment.

METHODS

Deidentified patient IVD tissues were collected after surgery under the Orthopedic Information, Tissue and Implant Repository (ORA L00011021). IVD cells were isolated and cultured in monolayer. IL-4R protein expression was analyzed using immunocytochemistry. To test if the IL-4R was responsive to its ligand, signal transducer and activator of transcription 6 (STAT6) phosphorylation was analyzed on cell lysates of IVD cells treated with recombinant human IL-4 for 30 minutes using enzyme linked immunosorbent assay kit. Gene expression analysis of IL-4 up- and downregulated genes were analyzed using real-time RT-PCR. Anti-inflammatory effects of IL-4 were determined by cotreating disc cells with lipopolysaccharide (LPS) and IL-4 and measuring gene expression and protein release of inflammatory markers, IL-6 and IL-8. The significance of differences among means of data on gene expression and protein analyses were analyzed by one-way analysis of variance or student t test. Differences were considered significant when the p value was below 0.05.

RESULTS

Immunocytochemistry staining for IL-4Rα in primary IVD cells (n=8) showed the majority of immunopositive staining was intracellular. After IVD cells (n=3-7) were treated with different concentrations of recombinant human IL-4 (0.1-100 ng/mL) for 30 minutes, phospho-STAT6 levels significantly increased by two- to four-fold at all concentrations tested compared with untreated cells. Gene expression of IL-4Rα and IL-6 increased significantly in cells undergoing IL-4 treatment for 24 hours compared with control treated IVD cells (n=5-10). LPS stimulated inflammatory gene expression of interferon (IFN)β, IL-12, IL-6, and IL-8 were downregulated significantly in the presence of IL-4 (n=7). Lastly, protein release of IL-6 and IL-8 were reduced significantly in cells treated with IL-4 and LPS compared with those treated with LPS alone (n=7).

CONCLUSIONS

This study was the first to explore the function of IL-4 and IL-4R in IVD cells. Immunocytochemistry studies confirmed that the majority of cells isolated from patient IVDs expressed IL-4Rα at the protein level. Also, IVD cells can respond to IL-4 by up-regulating IL-4Rα and IL-6 genes and inhibiting inflammatory genes and proteins induced by LPS. Further studies to test the anti-inflammatory effects of IL-4 in the IVD would be needed in animal models.

CLINICAL RELEVANCE

Biological therapies which include intradiscal delivery of cells, anti-inflammatories or growth factors are being investigated to treat disc degeneration and back pain in animal models and in the clinic. Based on our findings that IL-4 has anti-inflammatory effects on IVD cells, the results of this study suggest including recombinant IL-4 delivery into the intervertebral disc may be a beneficial therapeutic strategy to treat patients with back pain by reducing disc inflammation.

Functions and regulation of T cell-derived interleukin-10

Interleukin (IL)-10 is an essential anti-inflammatory cytokine and functions as a negative regulator of immune responses to microbial antigens. IL-10 is particularly important in maintaining the intestinal microbe-immune homeostasis. Loss of IL-10 promotes the development of inflammatory bowel disease (IBD) as a consequence of an excessive immune response to the gut microbiota. IL-10 also functions more generally to prevent excessive inflammation during the course of infection. Although IL-10 can be produced by virtually all cells of the innate and adaptive immune system, T cells constitute a non-redundant source for IL-10 in many cases. The various roles of T cell-derived IL-10 will be discussed in this review. Given that IL-10 is at the center of maintaining the delicate balance between effective immunity and tissue protection, it is not surprising that IL-10 expression is highly dynamic and tightly regulated. We summarize the environmental signals and molecular pathways that regulate IL-10 expression. While numerous studies have provided us with a deep understanding of IL-10 biology, the majority of findings have been made in murine models, prompting us to highlight gaps in our knowledge about T cell-derived IL-10 in the human system.

Maternal, placental and cord blood cytokines and the risk of adverse birth outcomes among pregnant women infected with Schistosoma japonicum in the Philippines

BACKGROUND

The objectives of this study were to 1) evaluate the influence of treatment with praziquantel on the inflammatory milieu in maternal, placental, and cord blood, 2) assess the extent to which proinflammatory signatures in placental and cord blood impacts birth outcomes, and 3) evaluate the impact of other helminths on the inflammatory micro environment.

METHODS/FINDINGS

This was a secondary analysis of samples from 369 mother-infant pairs participating in a randomized controlled trial of praziquantel given at 12-16 weeks' gestation. We performed regression analysis to address our study objectives. In maternal peripheral blood, the concentrations of CXCL8, and TNF receptor I and II decreased from 12 to 32 weeks' gestation, while IL-13 increased. Praziquantel treatment did not significantly alter the trajectory of the concentration of any of the cytokines examined. Hookworm infection was associated with elevated placental IL-1, CXCL8 and IFN-γ. The risk of small-for-gestational age increased with elevated IL-6, IL-10, and CXCL8 in cord blood. The risk of prematurity was increased when cord blood sTNFRI and placental IL-5 were elevated.

CONCLUSIONS

Our study suggests that fetal cytokines, which may be related to infectious disease exposures, contribute to poor intrauterine growth. Additionally, hookworm infection influences cytokine concentrations at the maternal-fetal interface.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE

ClinicalTrials.gov (NCT00486863).

Current Advances in Immunomodulatory Biomaterials for Bone Regeneration

Biomaterials with suitable surface modification strategies are contributing significantly to the rapid development of the field of bone tissue engineering. Despite these encouraging results, utilization of biomaterials is poorly translated to human clinical trials potentially due to lack of knowledge about the interaction between biomaterials and the body defense mechanism, the "immune system". The highly complex immune system involves the coordinated action of many immune cells that can produce various inflammatory and anti-inflammatory cytokines. Besides, bone fracture healing initiates with acute inflammation and may later transform to a regenerative or degenerative phase mainly due to the cross-talk between immune cells and other cells in the bone regeneration process. Among various immune cells, macrophages possess a significant role in the immune defense, where their polarization state plays a key role in the wound healing process. Growing evidence shows that the macrophage polarization state is highly sensitive to the biomaterial's physiochemical properties, and advances in biomaterial research now allow well controlled surface properties. This review provides an overview of biomaterial-mediated modulation of the immune response for regulating key bone regeneration events, such as osteogenesis, osteoclastogenesis, and inflammation, and it discusses how these strategies can be utilized for future bone tissue engineering applications.

Cutting Edge: Quantitative Determination of CD40L Threshold for IL-12 and IL-23 Production from Dendritic Cells

Early secretion of IL-12 by mouse dendritic cells (DCs) instructs T cells to make IFN-γ. However, only activated, but not naive T cells are able to license DCs for IL-12 production. We hypothesized that it might be due to different levels of CD40L expression on the surface of these cells, as CD40 signals are required for IL-12 production. Using quantitative cell-free systems incorporating CD40L in lipid bilayers combined with total internal reflection fluorescence microscopy and flow cytometry, we show that as low as ∼200 CD40L molecules/μm2 in combination with IL-4 is sufficient to induce IL-12 production by DCs. Remarkably, CD40L alone is adequate to induce IL-23 secretion by DCs. Thus, although activated T cells have somewhat higher levels of CD40L, it is the combination of CD40L and the cytokines they secrete that licenses DCs and influences the effector class of the immune response.

Differential S1P Receptor Profiles on M1- and M2-Polarized Macrophages Affect Macrophage Cytokine Production and Migration

Introduction. Macrophages are key players in complex biological processes. In response to environmental signals, macrophages undergo polarization towards a proinflammatory (M1) or anti-inflammatory (M2) phenotype. Sphingosine 1-phosphate (S1P) is a bioactive lysophospholipid that acts via 5 G-protein coupled receptors (S1P_1–5) in order to influence a broad spectrum of biological processes. This study assesses S1P receptor expression on macrophages before and after M1 and M2 polarization and performs a comparative analysis of S1P signalling in the two activational states of macrophages. Methods. Bone marrow derived macrophages (BMDM) from C57 BL/6 mice were cultured under either M1- or M2-polarizing conditions. S1P-receptor expression was determined by quantitative RT-PCR. Influence of S1P on macrophage activation, migration, phagocytosis, and cytokine secretion was assessed in vitro. Results. All 5 S1P receptor subclasses were expressed in macrophages. Culture under both M1- and M2-polarizing conditions led to significant downregulation of S1P₁. In contrast, M1-polarized macrophages significantly downregulated S1P₄. The expression of the remaining three S1P receptors did not change. S1P increased expression of iNOS under M2-polarizing conditions. Furthermore, S1P induced chemotaxis in M1 macrophages and changed cytokine production in M2 macrophages. Phagocytosis was not affected by S1P-signalling. Discussion. The expression of different specific S1P receptor profiles may provide a possibility to selectively influence M1- or M2-polarized macrophages.

Impact of interleukin 13 (IL13) genetic polymorphism Arg130Gln on total serum immunoglobulin (IgE) levels and interferon (IFN)-γ gene expression

This cross-sectional study was designed to investigate the extent of genetic susceptibility by targeting variants in interleukin (IL)-4/IL-13 signalling pathways leading to atopic disease in early childhood. We evaluated involvement of five single nucleotide polymorphisms IL4 C-590T, IL13 C-1055T, IL13 Arg130Gln, IL4RA Ile50Val and IL4RA Gln576Arg, in the control of serum total and antigen-specific immunoglobulin (Ig)E levels. Furthermore, we analysed their association with changes in gene expression of five cytokines having key roles in inflammatory and anti-inflammatory immune response [IL-4, IL-13, interferon (IFN)-γ, IL-8 and IL-10]. Total and antigen-specific IgE levels in serum and gene expression of selected cytokines in peripheral blood were measured in 386 children aged 1-8 years. TaqMan allelic discrimination, amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and restriction fragment length polymorphisms (RFLP) methods validated by sequencing were used for genotyping. All genotypes for children with total and antigen-specific IgE levels in the normal range were in Hardy-Weinberg equilibrium. Gene expression analyses were carried out using TaqMan gene expression assays. We found elevated total IgE levels in carriers of IL13 Arg130Gln variant allele [odds ratio (OR) = 1·84; 95% confidence interval (CI) = 1·16-2·93]. This effect was more apparent for boys (OR = 2·31; 95% CI = 1·25-4·28). However, no significant association was observed for the other four variants examined. We found up-regulation of IFN-γ in children with elevated serum total IgE levels carrying the Arg130 allele (P = 0·005). No differences were found for IL4, IL8 or IL10, while IL13 gene expression was under the detection limit. IL13 Arg130Gln genotypes can play a role in genetic susceptibility to allergy via regulation of serum total IgE levels and affecting IFN-γ gene expression.

Interferon-γ counteracts reduced endotoxin responsiveness of whole blood following trauma and cardiopulmonary bypass

Accidental as well as surgical trauma has been reported to cause reduced endotoxin responsiveness of blood in terms of cytokine production. In this study, the effect of interferon-γ (IFN-γ) on tumour necrosis factor-α (TNF-α)-producing capacity of whole blood after severe trauma and cardiac surgery was investigated. Blood samples of severely injured patients were collected at the first day after trauma and of cardiac surgery patients before, 4 h and 2 days after cardiopulmonary bypass (CPB). The blood samples were incubated with INF-γ (0—100 U/ml) for 20 h and subsequently lipopolysaccharide (LPS)-induced TNF-α production was determined. Compared to healthy donors, LPS-induced TNF-α production was significantly reduced in blood cultures of trauma patients on day 1 after trauma and 4 h after CPB. Pre-incubation with IFN-γ in vitro increased endotoxin-induced TNF-α production in volunteers' and all patients' blood specimens in a dose-dependent manner. IFN-γ prompted an elevation of cytokine synthesis in CPB patients' blood which equalled that of volunteers, whereas it caused a lower rise in TNF-α production in blood of multiply injured patients, reaching levels of untreated donors only after incubation with 100 U/ml IFN-γ. These experiments show that hyporesponsiveness of whole blood induced by trauma or cardiac surgery with CPB is not irreversible, but can be counteracted by the immunostimulant IFN-γ. IFN-γ, therefore, could be applied clinically in trauma patients or after cardiac surgery to prevent or to resolve infection complications.

Protective inflammatory response against visceral leishmaniasis with potato tuber extract: A new approach of successful therapy

The increasing number of drug resistance issue of Leishmania donovani strain to common drugs compels to develop new therapeutics against leishmaniasis with minimal toxicity. In this regard, bioactive phytocomponents may lead to the discovery of new medicines with appropriate efficiency. The important roles of Leishmania proteases in the virulence of Leishmania parasite make them very hopeful targets for the improvement of current remedial of leishmaniasis. As part of a hunt for new drugs, we have evaluated in vivo anti-leishmanial activity of serine protease inhibitor rich fraction (PTEx), isolated by sodium bisulfite extraction from potato tuber. The amastigote load of 25mg/kg body weight/day treated BALB/c mice showed 86.9% decrease in liver and 88.7% in case of spleen. This anti-leishmanial effect was also supported by PTEx induced immunomodulatory activity like acute formation of ROS and prolonged NO generation. The Th1/Th2 cytokine balance in splenocytes of PTEx treated animals was estimated and evaluated by ELISA assay as well as by mRNA expression using RT-PCR. Furthermore, significant survival rate (80%) was observed in PTEx treated hamsters. Thus, from the present observations we could accentuate the potential of PTEx to be employed as a new therapeutics from natural source against L. donovani. This might also provide a novel perception of natural serine protease inhibitor from potato tuber as an alternate approach for the treatment of visceral leishmaniasis.

Ingested (oral) anti-IL-12/23 inhibits EAE

BACKGROUND

Blocking the activity of IL-12/23 can inhibit autoimmune diseases such as psoriasis.

OBJECTIVE

We examined whether an antibody against IL-12/23, ustekinumab (UTZ) (Stelera®), used clinically in psoriasis would have similar anti-inflammatory effects in EAE after oral administration.

DESIGN/METHODS

B6 mice were immunized with MOG peptide 35-55 and gavaged with isotype IgG control or UTZ during ongoing disease. Splenocytes, CD4(+) T cells or macrophages/monocyte lineage cells (CD11b(+)) from control fed or UTZ fed mice were adoptively transferred into active MOG peptide 35-55 immunized recipient mice during ongoing disease. Actively fed and recipient mice were examined for disease inhibition, inflammation, and cytokine responses.

RESULTS

Ingested (oral) UTZ inhibited ongoing disease and decreased inflammation. Adoptively transferred cells from UTZ fed donors protected against actively induced disease and decreased inflammation. Oral UTZ decreased pro-inflammatory cytokines Th1-like cytokines IL-2, IL-12, IFN-γ, IL-17 (Teff) and TNF-α in UTZ fed mice and increased counter-regulatory cytokines IL-4, IL-10 and IL-13 in recipients of donor cells from UTZ fed mice.

CONCLUSIONS

Ingested (orally administered) UTZ can inhibit disease, CNS inflammation, decrease pro-inflammatory Th1-like and Th17 cytokines and increase Th2-like anti-inflammatory cytokines.

TGF-β1, but not bone morphogenetic proteins, activates Smad1/5 pathway in primary human macrophages and induces expression of proatherogenic genes

Macrophages are responsible for the control of inflammation and healing, and their malfunction results in cardiometabolic disorders. TGF-β is a pleiotropic growth factor with dual (protective and detrimental) roles in atherogenesis. We have previously shown that in human macrophages, TGF-β1 activates Smad2/3 signaling and induces a complex gene expression program. However, activated genes were not limited to known Smad2/3-dependent ones, which prompted us to study TGF-β1-induced signaling in macrophages in detail. Analysis of Id3 regulatory sequences revealed a novel enhancer, located between +4517 and 4662 bp, but the luciferase reporter assay demonstrated that this enhancer is not Smad2/3 dependent. Because Id3 expression is regulated by Smad1/5 in endothelial cells, we analyzed activation of Smad1/5 in macrophages. We demonstrate here for the first time, to our knowledge, that TGF-β1, but not BMPs, activates Smad1/5 in macrophages. We show that an ALK5/ALK1 heterodimer is responsible for the induction of Smad1/5 signaling by TGF-β1 in mature human macrophages. Activation of Smad1/5 by TGF-β1 induces not only Id3, but also HAMP and PLAUR, which contribute to atherosclerotic plaque vulnerability. We suggest that the balance between Smad1/5- and Smad2/3-dependent signaling defines the outcome of the effect of TGF-β on atherosclerosis where Smad1/5 is responsible for proatherogenic effects, whereas Smad2/3 regulate atheroprotective effects of TGF-β.

Interleukin-1 and interferon-γ orchestrate β-glucan-activated human dendritic cell programming via IκB-ζ modulation

Recognition of microbial components via innate receptors including the C-type lectin receptor Dectin-1, together with the inflammatory environment, programs dendritic cells (DCs) to orchestrate the magnitude and type of adaptive immune responses. The exposure to β-glucan, a known Dectin-1 agonist and component of fungi, yeasts, and certain immune support supplements, activates DCs to induce T helper (Th)17 cells that are essential against fungal pathogens and extracellular bacteria but may trigger inflammatory pathology or autoimmune diseases. However, the exact mechanisms of DC programming by β-glucan have not yet been fully elucidated. Using a gene expression/perturbation approach, we demonstrate that in human DCs β-glucan transcriptionally activates via an interleukin (IL)-1- and inflammasome-mediated positive feedback late-induced genes that bridge innate and adaptive immunity. We report that in addition to its known ability to directly prime T cells toward the Th17 lineage, IL-1 by promoting the transcriptional cofactor inhibitor of κB-ζ (IκB-ζ) also programs β-glucan-exposed DCs to express cell adhesion and migration mediators, antimicrobial molecules, and Th17-polarizing factors. Interferon (IFN)-γ interferes with the IL-1/IκB-ζ axis in β-glucan-activated DCs and promotes T cell-mediated immune responses with increased release of IFN-γ and IL-22, and diminished production of IL-17. Thus, our results identify IL-1 and IFN-γ as regulators of DC programming by β-glucan. These molecular networks provide new insights into the regulation of the Th17 response as well as new targets for the modulation of immune responses to β-glucan-containing microorganisms.

Macrophage IL-10 blocks CD8+ T cell-dependent responses to chemotherapy by suppressing IL-12 expression in intratumoral dendritic cells

Blockade of colony-stimulating factor-1 (CSF-1) limits macrophage infiltration and improves response of mammary carcinomas to chemotherapy. Herein we identify interleukin (IL)-10 expression by macrophages as the critical mediator of this phenotype. Infiltrating macrophages were the primary source of IL-10 within tumors, and therapeutic blockade of IL-10 receptor (IL-10R) was equivalent to CSF-1 neutralization in enhancing primary tumor response to paclitaxel and carboplatin. Improved response to chemotherapy was CD8(+) T cell-dependent, but IL-10 did not directly suppress CD8(+) T cells or alter macrophage polarization. Instead, IL-10R blockade increased intratumoral dendritic cell expression of IL-12, which was necessary for improved outcomes. In human breast cancer, expression of IL12A and cytotoxic effector molecules were predictive of pathological complete response rates to paclitaxel.

Ingested (oral) tocilizumab inhibits EAE

BACKGROUND

Blocking the activity of IL-6 can inhibit autoimmune diseases such as rheumatoid arthritis and Crohn's disease.

OBJECTIVE

We examined whether an antibody against IL-6, tocilizumab (TCZ) (Actemra®), used clinically in rheumatoid arthritis (RA) would have similar anti-inflammatory effects in EAE after oral administration.

DESIGN/METHOD

B6 mice were immunized with MOG peptide 35-55 and gavaged with control saline or TCZ during ongoing disease. Splenocytes, CD4(+) T cells or macrophages/monocyte lineage cells (CD11b(+)) from control fed or TCZ fed mice were adoptively transferred into active MOG peptide 35-55 immunized recipient mice during ongoing disease. Actively fed and recipient mice were examined for disease inhibition, inflammation, and cytokine responses.

RESULTS

Ingested (oral) TCZ inhibited ongoing disease and decreased inflammation. Adoptively transferred cells from TCZ fed donors protected against actively induced disease and decreased inflammation. There was a decrease in IL-6 in actively treated spleen, decrease in TNF-α, Th1-like cytokine IL-12 and increase in Th2-like cytokine IL-10 in active fed and adoptively treated recipients.

CONCLUSIONS

Ingested (orally administered) TCZ can inhibit disease, CNS inflammation, decrease pro-inflammatory Th1-like cytokines and increase Th2-like anti-inflammatory cytokines.

IL-4 receptor-alpha-dependent control of Cryptococcus neoformans in the early phase of pulmonary infection

Cryptococcus neoformans is an opportunistic fungal pathogen that causes lung inflammation and meningoencephalitis in immunocompromised people. Previously we showed that mice succumb to intranasal infection by induction of pulmonary interleukin (IL)-4Rα-dependent type 2 immune responses, whereas IL-12-dependent type 1 responses confer resistance. In the experiments presented here, IL-4Rα⁻/⁻ mice unexpectedly show decreased fungal control early upon infection with C. neoformans, whereas wild-type mice are able to control fungal growth accompanied by enhanced macrophage and dendritic cell recruitment to the site of infection. Lower pulmonary recruitment of macrophages and dendritic cells in IL-4Rα⁻/⁻ mice is associated with reduced pulmonary expression of CCL2 and CCL20 chemokines. Moreover, IFN-γ and nitric oxide production are diminished in IL-4Rα⁻/⁻ mice compared to wild-type mice. To directly study the potential mechanism(s) responsible for reduced production of IFN-γ, conventional dendritic cells were stimulated with C. neoformans in the presence of IL-4 which results in increased IL-12 production and reduced IL-10 production. Together, a beneficial role of early IL-4Rα signaling is demonstrated in pulmonary cryptococcosis, which contrasts with the well-known IL-4Rα-mediated detrimental effects in the late phase.

IL-4 contributes to failure, and colludes with IL-10 to exacerbate Leishmania donovani infection following administration of a subcutaneous leishmanial antigen vaccine

Background

Visceral leishmaniasis caused by the protozoan parasite Leishmania donovani complex is a potentially fatal disease if left untreated. Few treatment options exist and are toxic, costly and ineffective against resistant strains. Thus a safe and efficacious vaccine to combat this disease is needed. Previously, we reported that intraperitoneal administration of leishmanial antigens (LAg) entrapped in liposomes conferred protection to BALB/c mice against L. donovani challenge infection. However, this vaccine failed to protect mice when administered subcutaneously. We therefore evaluated whether formulation of LAg in combination with two commonly used human-compatible adjuvants, alum and saponin, could improve the protective efficacy of subcutaneously administered LAg, to a level comparable to that of the intraperitoneal liposomal vaccination.

Results

Vaccine formulations of LAg with alum or saponin failed to reduce parasite burden in the liver, and alum + LAg immunized mice also failed to reduce parasite burden in the spleen. Interestingly, saponin + LAg vaccination actually resulted in an increased L. donovani parasitic load in the spleen following L. donovani challenge, suggesting this regimen exacerbates the infection. In contrast, mice immunized intraperitoneally with Lip + LAg demonstrated significant protection in both liver and spleen, as expected. Mechanistically, we found that failure of alum + LAg to protect mice was associated with elevated levels of IL-4, whereas both IL-4 and IL-10 levels were increased in saponin + LAg immunized mice. This outcome served to exacerbate L. donovani infection in the saponin + LAg group, despite a concurrent increase in proinflammatory IFN-γ production. On the contrary, protection against L. donovani challenge in Lip + LAg immunized mice was associated with elevated levels of IFN-γ in conjunction with low levels of IL-4 and IL-10 production.

Conclusions

These findings indicate that elevated levels of IL-4 may contribute to LAg vaccine failure, whereas combined elevation of IL-4 together with IL-10 exacerbated the disease as observed in saponin + LAg immunized mice. In contrast, a robust IFN-γ response, in the absence of IL-4 and IL-10 production, was associated with protective immunity following administration of the Lip + LAg vaccine. Together these findings suggest that optimization of antigen/adjuvant formulations to minimize IL-4 and IL-10 induction may be helpful in the development of high efficacy vaccines targeting Leishmania.

The cytolethal distending toxin of Aggregatibacter actinomycetemcomitans inhibits macrophage phagocytosis and subverts cytokine production

Aggregatibacter actinomycetemcomitans is an important periodontal pathogen that can participate in periodontitis and other non-oral infections. The cytolethal distending toxin (Cdt) is among the virulence factors produced by this bacterium. The Cdt is also secreted by several mucosa-associated Gram-negative pathogens and may play a role in perpetuating the infection by modulating the immune response. Although the toxin targets a wide range of eukaryotic cell types little is known about its activity on macrophages which play a key part in alerting the rest of the immune system to the presence of pathogens and their virulence factors. In view of this, we tested the hypothesis that the A. actinomycetemcomitans Cdt (AaCdt) disrupts macrophage function by inhibiting phagocytic activity as well as affecting the production of cytokines. Murine macrophages were co-cultured with either wild-type A. actinomycetemcomitans or a Cdt(-) mutant. Viable counts and qPCR showed that phagocytosis of the wild-type strain was significantly reduced relative to that of the Cdt(-) mutant. Addition of recombinant Aa(r)Cdt to co-cultures along with the Cdt(-) mutant diminished the phagocytic activity similar to that observed with the wild type strain. High concentrations of Aa(r)Cdt resulted in decreased phagocytosis of fluorescent bioparticles. Nitric oxide production was modulated by the presence of Cdt and the levels of IL-1β, IL-12 and IL-10 were increased. Production of TNF-α did not differ in the co-culture assays but was increased by the presence of Aa(r)Cdt. These data suggest that the Cdt may modulate macrophage function in A. actinomycetemcomitans infected sites by impairing phagocytosis and modifying the pro-inflammatory/anti-inflammatory cytokine balance.

Induction of protection against leishmaniasis in susceptible BALB/c mice using simple DOTAP cationic nanoliposomes containing soluble Leishmania antigen (SLA)

A suitable adjuvant and delivery system are needed to develop an effective vaccine against leishmaniasis. To induce a Th1 type of response and protection in BALB/c mice against Leishmania major infection, 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) nanoliposomes bearing an intrinsic adjuvanticity, were used as an antigen delivery system and immunoadjuvant for soluble Leishmania antigens (SLA). DOTAP liposomes containing different concentrations of SLA were prepared by using lipid film method followed by sonication. The prepared vesicles showed a diameter of about 100nm, a positive zeta potential and approximately 70% encapsulation efficiency of SLA. BALB/c mice were immunized subcutaneously (SC), three times in a 3-week interval with different concentrations of liposomal SLA (12.5, 25, and 50μg of SLA/50μl/mice), free SLA and as well as free liposome. The group of mice received 50μg of SLA in DOTAP-nanoliposomes showed a significantly (p<0.001) smaller footpad swelling and the lowest spleen and footpad parasite burden after the challenge. This group also showed the highest IFN-γ production compared to the other groups, lower IL-4 level and higher IgG2a antibody titer. Taken together, the results indicated that simple DOTAP nanoliposome containing 1μg/μl SLA are appropriate delivery systems to induce a Th1 type of immune response and protection against L. major infection in BALB/c mice.

Deletion of IL-4 receptor alpha on dendritic cells renders BALB/c mice hypersusceptible to Leishmania major infection

In BALB/c mice, susceptibility to infection with the intracellular parasite Leishmania major is driven largely by the development of T helper 2 (Th2) responses and the production of interleukin (IL)-4 and IL-13, which share a common receptor subunit, the IL-4 receptor alpha chain (IL-4Rα). While IL-4 is the main inducer of Th2 responses, paradoxically, it has been shown that exogenously administered IL-4 can promote dendritic cell (DC) IL-12 production and enhance Th1 development if given early during infection. To further investigate the relevance of biological quantities of IL-4 acting on DCs during in vivo infection, DC specific IL-4Rα deficient (CD11c(cre)IL-4Rα(-/lox)) BALB/c mice were generated by gene targeting and site-specific recombination using the cre/loxP system under control of the cd11c locus. DNA, protein, and functional characterization showed abrogated IL-4Rα expression on dendritic cells and alveolar macrophages in CD11c(cre)IL-4Rα(-/lox) mice. Following infection with L. major, CD11c(cre)IL-4Rα(-/lox) mice became hypersusceptible to disease, presenting earlier and increased footpad swelling, necrosis and parasite burdens, upregulated Th2 cytokine responses and increased type 2 antibody production as well as impaired classical activation of macrophages. Hypersusceptibility in CD11c(cre)IL-4Rα(-/lox) mice was accompanied by a striking increase in parasite burdens in peripheral organs such as the spleen, liver, and even the brain. DCs showed increased parasite loads in CD11c(cre)IL-4Rα(-/lox) mice and reduced iNOS production. IL-4Rα-deficient DCs produced reduced IL-12 but increased IL-10 due to impaired DC instruction, with increased mRNA expression of IL-23p19 and activin A, cytokines previously implicated in promoting Th2 responses. Together, these data demonstrate that abrogation of IL-4Rα signaling on DCs is severely detrimental to the host, leading to rapid disease progression, and increased survival of parasites in infected DCs due to reduced killing effector functions.

Characterization of polarized THP-1 macrophages and polarizing ability of LPS and food compounds

Little is known about the polarizing potential of currently used human macrophage cell lines, while a better understanding phenomena can support the prediction of effects in vivo based on in vitro analysis. To test the polarization capability of PMA differentiated-THP-1 macrophages (M0), cells were stimulated with 20 ng ml(-1) IFNγ + 1 μg ml(-1) LPS and 20 ng ml(-1) IL-4, which are known to influence macrophage polarization in vivo and ex vivo into the M1 and M2 state, respectively. Apart from several well-known M1 and M2 markers, also new possible markers for M1 and M2 polarization were analysed in this study. The expression of M1 marker genes was up-regulated in IFNγ + LPS stimulated-M0 THP-1 macrophages. The IL-4 stimulated-M0 THP-1 macrophages expressed M2 cell membrane receptor genes. However, M2 chemokine and their receptor genes were only slightly up-regulated which might be due to the complexity of the secondary cell-cell interaction of the chemokine system. Lipopolysaccharides from E. coli (LPS) and food compounds [lentinan, vitamin D3 (vD3) and the combination of lentinan + vitamin D3 (Len + vD3)] were investigated for their polarizing ability on M0 THP-1 macrophages towards either the M1 or M2 state. LPS (700 ng ml(-1)) was able to skew M0 THP-1 macrophages towards the M1 direction since all analysed M1 marker genes were strongly expressed. Lentinan, vD3 and Len + vD3 did not induce expression of either M1 or M2 markers, indicating no polarizing ability of these compounds. Based on the expression of M1 and M2 marker genes we concluded that THP-1 macrophages could be successfully polarized into either the M1 or M2 state. Therefore, they can be used as a new macrophage polarizing model to estimate the polarizing/switching ability of test food compounds.

Interleukin (IL)-31 activates signal transducer and activator of transcription (STAT)-1, STAT-5 and extracellular signal-regulated kinase 1/2 and down-regulates IL-12p40 production in activated human macrophages

BACKGROUND

Interleukin-31 is a cytokine expressed by activated T cells. A major function of IL-31 in atopic dermatitis (AD) is the induction of pruritus in the skin. We recently showed that IL-31 induces pro-inflammatory cytokines following staphylococcal exotoxins' stimulation in human macrophages. However, signalling pathways of IL-31 in activated human macrophages still remain unclear. The aim of the study was to investigate the signalling pathways of IL-31 receptor as well as functional effects of IL-31 in activated macrophages.

METHODS

Human macrophages were prestimulated with staphylococcal exotoxins (SEB, α-toxin) to up-regulate the IL-31 receptor with and without IL-31. Phospho-signal transducer and activator of transcription (pSTAT) 1/3/5, phospho-extracellular signal-regulated kinase (ERK 1/2), β-actin as well as p21/WAF/Cip1 levels were determined by means of Western blot analysis. Interleukin-12p40, IL-12p70 and IL-23 secretions were assessed by using an enzyme-linked immunosorbent assay.

RESULTS

Interleukin-31 strongly activated STAT-1 and 5 but not STAT-3 in human macrophages after up-regulation of IL-31 receptor with staphylococcal exotoxins. p21/WAF/Cip1 expression was induced by IL-31 in activated human macrophages. Furthermore, IL-31 down-regulated. IL-12p40 secretion via ERK 1/2 phosphorylation in human macrophages following up-regulation of IL-31 receptor with staphylococcal exotoxins.

CONCLUSIONS

The T helper (Th) 2 cytokine IL-31 induces pro-inflammatory effects in activated human macrophages via STAT-1 and 5 phosphorylation. Interleukin-31-induced ERK 1/2 activation contributes to the underlying mechanism of Th1 cytokine IL-12 suppression in macrophages. This mechanism may be relevant in Th2 inflammatory responses and may help to develop therapeutic strategies in IL-31-associated diseases such as AD.

Induction of IL-4Rα-dependent microRNAs identifies PI3K/Akt signaling as essential for IL-4-driven murine macrophage proliferation in vivo

Macrophage (MΦ) activation must be tightly controlled to preclude overzealous responses that cause self-damage. MicroRNAs promote classical MΦ activation by blocking antiinflammatory signals and transcription factors but also can prevent excessive TLR signaling. In contrast, the microRNA profile associated with alternatively activated MΦ and their role in regulating wound healing or antihelminthic responses has not been described. By using an in vivo model of alternative activation in which adult Brugia malayi nematodes are implanted surgically in the peritoneal cavity of mice, we identified differential expression of miR-125b-5p, miR-146a-5p, miR-199b-5p, and miR-378-3p in helminth-induced MΦ. In vitro experiments demonstrated that miR-378-3p was specifically induced by IL-4 and revealed the IL-4-receptor/PI3K/Akt-signaling pathway as a target. Chemical inhibition of this pathway showed that intact Akt signaling is an important enhancement factor for alternative activation in vitro and in vivo and is essential for IL-4-driven MΦ proliferation in vivo. Thus, identification of miR-378-3p as an IL-4Rα-induced microRNA led to the discovery that Akt regulates the newly discovered mechanism of IL-4-driven macrophage proliferation. Together, the data suggest that negative regulation of Akt signaling via microRNAs might play a central role in limiting MΦ expansion and alternative activation during type 2 inflammatory settings.

Dendritic cell-mediated vaccination relies on interleukin-4 receptor signaling to avoid tissue damage after Leishmania major infection of BALB/c mice

Prevention of tissue damages at the site of Leishmania major inoculation can be achieved if the BALB/c mice are systemically given L. major antigen (LmAg)-loaded bone marrow-derived dendritic cells (DC) that had been exposed to CpG-containing oligodeoxynucleotides (CpG ODN). As previous studies allowed establishing that interleukin-4 (IL-4) is involved in the redirection of the immune response towards a type 1 profile, we were interested in further exploring the role of IL-4. Thus, wild-type (wt) BALB/c mice or DC-specific IL-4 receptor alpha (IL-4Rα)-deficient (CD11c^creIL-4Rα^−/lox) BALB/c mice were given either wt or IL-4Rα-deficient LmAg-loaded bone marrow-derived DC exposed or not to CpG ODN prior to inoculation of 2×10⁵ stationary-phase L. major promastigotes into the BALB/c footpad. The results provide evidence that IL4/IL-4Rα-mediated signaling in the vaccinating DC is required to prevent tissue damage at the site of L. major inoculation, as properly conditioned wt DC but not IL-4Rα-deficient DC were able to confer resistance. Furthermore, uncontrolled L. major population size expansion was observed in the footpad and the footpad draining lymph nodes of CD11c^creIL-4Rα^−/lox mice immunized with CpG ODN-exposed LmAg-loaded IL-4Rα-deficient DC, indicating the influence of IL-4Rα-mediated signaling in host DC to control parasite replication. In addition, no footpad damage occurred in BALB/c mice that were systemically immunized with LmAg-loaded wt DC doubly exposed to CpG ODN and recombinant IL-4. We discuss these findings and suggest that the IL4/IL4Rα signaling pathway could be a key pathway to trigger when designing vaccines aimed to prevent damaging processes in tissues hosting intracellular microorganisms.

Cutaneous leishmaniasis is endemic in tropical and subtropical regions of the world. Effective vaccination strategies are urgently needed because of the emergence of drug-resistant parasites and severe side effects of chemotherapy. We previously established a DC-based vaccination strategy to induce complete and long-lasting immunity to experimental leishmaniasis using Leishmania major antigen-loaded and CpG oligodeoxynucleotide-activated DC as a vaccine carrier. In the present study we investigated the role of IL-4Rα-mediated instruction of the vaccinating DC and the host DC during induction of protection against leishmaniasis. The results demonstrate that IL-4Rα signaling in DC used as vaccine carrier plays an important role in induction of protective immunity against L. major infection, as only mice vaccinated with IL-4 responder DC are able to trigger effective Th1-mediated immunity. The immunity is hallmarked by high levels of L. major-induced bioactive IL-12 production in the lymph nodes of vaccinated mice. Together, these findings suggest that IL-4 is a strong adjuvant to induce Th1-biased immunity against leishmaniasis and possibly other infections with intracellular pathogens, indicating that IL-4 needs to be considered in the development of efficient cell-mediated vaccination strategies.

Effect of macrophage classical (M1) activation on implant-adherent macrophage interactions with Staphylococcus epidermidis: A murine in vitro model system

A model in vitro system was developed for eliciting classical (M1) activation of surface-adherent murine macrophages, which was then used to study the interaction of the M1 macrophages with Staphylococcus epidermidis. Glass substrata were first covalently grafted with a mixture of methoxy- and biotin-terminated silanated polyethylene glycol. Interferon (IFN)-γ and/or lipopolysaccharide (LPS), ligands known to induce the highly microbicidal M1 activation state in macrophages, were biotinylated and immobilized by way of a streptavidin intermediate to the biotin-PEG base substratum. Assessment of mouse bone marrow-derived macrophage (BMDM) interleukin (IL)-12(p40) and nitric oxide response to the fabricated surfaces confirmed that the model system achieved activation of adherent macrophage: IFN-γ-presenting surfaces primed cells for M1 activation, LPS-presenting surfaces elicited innate activation, and surface presenting a combination of IFN-γ and LPS induced M1 activation. The phagocytic and microbicidal capacity of activated, surface-adherent BMDM was evaluated using S. epidermidis, a bacterial species prevalent in implant-associated infections. Results indicate that M1 activation of implant-adherent macrophages trends towards diminishing their phagocytic capacity, but enhances their microbicidal capacity for S. epidermidis.

SPLUNC1 deficiency enhances airway eosinophilic inflammation in mice

Short palate, lung and nasal epithelium clone 1 (SPLUNC1) is enriched in normal airway lining fluid, but is significantly reduced in airway epithelium exposed to a Th2 cytokine milieu. The role of SPLUNC1 in modulating airway allergic inflammation (e.g., eosinophils) remains unknown. We used SPLUNC1 knockout (KO) and littermate wild-type (C57BL/6 background) mice and recombinant SPLUNC1 protein to determine the impact of SPLUNC1 on airway allergic/eosinophilic inflammation, and to investigate the underlying mechanisms. An acute ovalbumin (OVA) sensitization and challenge protocol was used to induce murine airway allergic inflammation (e.g., eosinophils, eotaxin-2, and Th2 cytokines). Our results showed that SPLUNC1 in the bronchoalveolar lavage fluid of OVA-challenged wild-type mice was significantly reduced (P < 0.05), which was negatively correlated with levels of lung eosinophilic inflammation. Moreover, SPLUNC1 KO mice demonstrated significantly higher numbers of eosinophils in the lung after OVA challenges than did wild-type mice. Alveolar macrophages isolated from OVA-challenged SPLUNC1 KO versus wild-type mice had higher concentrations of baseline eotaxin-2 that was amplified by LPS (a known risk factor for exacerbating asthma). Human recombinant SPLUNC1 protein was applied to alveolar macrophages to study the regulation of eotaxin-2 in the context of Th2 cytokine and LPS stimulation. Recombinant SPLUNC1 protein attenuated LPS-induced eotaxin-2 production in Th2 cytokine-pretreated murine macrophages. These findings demonstrate that SPLUNC1 inhibits airway eosinophilic inflammation in allergic mice, in part by reducing eotaxin-2 production in alveolar macrophages.

Liposomal SLA co-incorporated with PO CpG ODNs or PS CpG ODNs induce the same protection against the murine model of leishmaniasis

First generation Leishmania vaccines consisting of whole killed parasites with or without adjuvants have reached phase 3 trial and failed to show enough efficacy mainly due to the lack of an appropriate adjuvant. In this study, the nuclease-resistant phosphorothioate CpG oligodeoxynucleotides (PS CpG) or nuclease-sensitive phosphodiester CpG ODNs (PO CpG) were used as adjuvants to enhance immunogenicity and rate of protection against leishmaniasis. Due to the susceptibility of PO CpG to nuclease degradation, an efficient liposomal delivery system was developed to protect them from degradation. 1, 2-dioleoyl-3-trimethylammonium-propane (DOTAP) as a cationic lipid was used because of its unique adjuvanticity and electrostatic interaction with negatively charged CpG ODNs. To evaluate the role of liposomal formulation in protection rate and enhanced immune response, BALB/c mice were immunized subcutaneously with liposomal soluble Leishmania antigens (SLA) co-incorporated with PO CpG (Lip-SLA-PO CpG), Lip-SLA-PS CpG, SLA+PO CpG, SLA+PS CpG, SLA or buffer. As criteria for protection, footpad swelling at the site of challenge, parasite loads, the levels of IFN-γ and IL-4, and the IgG subtypes were evaluated. The groups of mice receiving Lip-SLA-PO CpG or Lip-SLA-PS CpG showed a high protection rate compared with the control groups. In addition, there was no significant difference in immune response generation between mice immunized with PS CpG and the group receiving PO CpG when incorporated into the liposomes. The results suggested that liposomal form of PO CpG might be used instead of PS CpG in future vaccine formulations as an efficient adjuvant.

Macrophage polarization in health and disease

Macrophages are terminally differentiated cells of the mononuclear phagocyte system that also encompasses dendritic cells, circulating blood monocytes, and committed myeloid progenitor cells in the bone marrow. Both macrophages and their monocytic precursors can change their functional state in response to microenvironmental cues exhibiting a marked heterogeneity. However, there are still uncertainties regarding distinct expression patterns of surface markers that clearly define macrophage subsets, particularly in the case of human macrophages. In addition to their tissue distribution, macrophages can be functionally polarized into M1 (proinflammatory) and M2 (alternatively activated) as well as regulatory cells in response to both exogenous infections and solid tumors as well as by systems biology approaches.

MicroRNA regulation of STAT4 protein expression: rapid and sensitive modulation of IL-12 signaling in human natural killer cells

IL-12 exerts several regulatory effects on natural killer (NK) cells by activating IL-12 signaling. IL-12 signaling is tightly auto-regulated to control its onset and termination, with prolonged IL-12 treatment resulting in IL-12 hyporesponsiveness. However, the mechanisms underlying IL-12 auto-regulation are still unclear. In this study we report that prolonged IL-12 treatment significantly up-regulates microRNAs (miRNAs), including miR-132, -212, and -200a in primary human NK cells. This up-regulation correlates temporally with gradually decreasing STAT4 levels and decreasing IFN-γ expression, after an initial increase within the first 16 hours of IL-12 treatment. The IL-12 hyporesponsiveness is dependent on IL-12 concentration, and associated up-regulation of miR-132, -212, and -200a. Furthermore, IL-12-hyporesponsive cells regain responsiveness of IFN-γ production 24 hours after IL-12 removal, which correlates with decreases in miR-132, -212, and -200a levels. Overexpression of miR-132, -212, and -200a by transfection into NK cells mimics IL-12 priming, inducing IL-12 hyporesponsiveness, whereas transfection of miR-132, -212, and -200a inhibitors largely abolishes IL-12 induction of IL-12 hyporesponsiveness. These data suggest that miR-132, -212, and -200a up-regulation during prolonged IL-12 treatment, negatively regulates the IL-12 signaling pathway by reducing STAT4 expression in primary human NK cells.

Lower levels of interleukin-12 precede the development of tuberculosis among HIV-infected women

Tuberculosis (TB) is the worldwide leading cause of death among HIV-infected individuals, accounting for more than half of AIDS-related deaths. A high risk of tuberculosis (TB) has been shown in early stages of the HIV disease, even in the presence of normal CD4(+) cell counts. Moreover, the factors that determine protective immunity vs. susceptibility to Mycobacterium tuberculosis cannot be fully explained by simple changes in IFNγ levels or a shift from Th1 to Th2 cytokines. This work investigated the relationship between cytokine expression profiles in peripheral blood mononuclear cells (PBMC) and susceptibility to M. tuberculosis in 10 HIV+ women who went onto develop TB. RNA transcripts for IL-4, IL-4δ2, IL-10, IL-12(p35), IL-13, IL-17A, IFNγ and TNFα were measured by real-time quantitative PCR in unstimulated or TB peptide antigen-stimulated PBMCs from 10 HIV+ women with positive tuberculin skin tests (TST) and compared with HIV-seropositive and seronegative women without previous TB and negative TST. Stimulated PBMC cultures showed significantly lower expression of IL-12p35 (p=0.004) and IL-10 (p=0.026) in the HIV+TB+ group 6-12months before onset of TB compared to HIV+TB- women. Unstimulated PBMC from HIV+TB+ women also had lower expression of Th2 cytokines [IL-4 (p=0.056) and IL-13 (p=0.050)] compared to HIV+TB- women. These results suggest that lower IL-12 production by PBMC in response to TB antigens and lower levels of both Th1 and Th2 cytokines by PBMC correlate with future development of TB in HIV-infected women and may be responsible for their increased susceptibility.

Modulatory role of calreticulin as chaperokine for dendritic cell-based immunotherapy

Heat shock proteins (HSPs) play a regulatory role for maturation of antigen-presenting cells (APCs) such as dendritic cells (DCs) and macrophages. Whereas HSP70 has been shown to enhance the maturation of human DCs via a nuclear factor kappa-B (NF-κB)-dependent pathway, the regulatory role of calreticulin (CRT), which is a HSP with similar functions to HSP70, is not well studied. To investigate the role of CRT as adjuvant in cell activation and co-stimulatory responses we determined the effects of CRT on human APC maturation in comparison to that of HSP70. To facilitate eukaryotic endotoxin-free CRT protein expression, three different methods were compared. We demonstrate that CRT induces the maturation of human DCs and increases the production of proinflammatory cytokines via the NF-κB pathway. CRT-mediated maturation was qualitatively similar to that induced by HSP70. Interestingly, priming of monocytes with HSPs showed an even more prominent effect on maturation than exposure of immature DCs to these compounds. A higher expression of CD86, CD83 and CCR7 on mature DCs were found in response to CRT. Our data provide novel insights into the role of extracellular HSPs as chaperokines in the processes of APC generation and may thus be useful to improve adoptive immunotherapy.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

Streptococcus cristatus attenuates Fusobacterium nucleatum-induced cytokine expression by influencing pathways converging on nuclear factor-κB

We previously reported that Streptococcus cristatus, an oral commensal, was able to downregulate the interleukin-8 (IL-8) response to Fusobacterium nucleatum, a putative oral pathogen in oral epithelial cells. The aim of this study was to extend the understanding of how S. cristatus regulates cytokine expression in oral epithelial cells on a broad basis, and investigate whether the modulation of a Toll-like receptor (TLR) pathway was involved in this process. KB and TERT-2 cells were co-cultured with F. nucleatum and S. cristatus, either alone or in combination. Total RNA was extracted and pathway-specific focused microarrays were used to profile the transcriptional responses of various cytokine genes and those related to TLR-mediated signal transduction. Reverse transcription-polymerase chain reactions (RT-PCR) and protein assays were performed to confirm the microarray results for selected genes. We found that exposure to either S. cristatus or F. nucleatum alone led to distinct changes in cytokine expression patterns. Fusobacterium nucleatum induced a greater number of gene expression changes than S. cristatus (15% vs. 4%, respectively). The presence of S. cristatus with F. nucleatum attenuated the expression of a number of inflammatory cytokines, and upregulated several anti-inflammatory mediators. The RT-PCR confirmed the messenger RNA attenuation of IL-1α, tumor necrosis factor-α and IL-6 by S. cristatus. Profiling of TLR-signaling-related genes revealed that S. cristatus most significantly impacted the downstream pathways, especially nuclear factor-κB, rather than altering TLRs and their adaptors and interacting proteins. Our data suggest that S. cristatus may attenuate the epithelial proinflammatory cytokine response to F. nucleatum by influencing pathways converging on nuclear factor-κB.