Diffuse large B-cell lymphoma-derived exosomes push macrophage polarization toward M2 phenotype via GP130/STAT3 signaling pathway.

Growing evidence shows that cancer progression links with both heterogeneity of the tumor microenvironment and dysregulated activity of immune cells. Cancer-secreted exosomes are being recognized as indispensable mediators of the exchange cargo between cancer and immune cells. The M2-phenotype tumor-associated macrophages have the function of promoting tumor progression and drug resistance. Diffuse large B-cell lymphoma(DLBCL) is a highly heterogeneous and very common malignant non-Hodgkin's lymphoma. Here, we demonstrate that different subtype DLBCL cell-derived exosomes are internalized by macrophages, which can affect macrophages polarization. The mechanism of DLBCL-derived exosomes on macrophage polarization remains unclear currently. This study showed that DLBCL-secreted exosomes could induce the transformation of macrophages to a protumor M2-like phenotype, and block the drug-induced apoptosis of DLBCL cells in an indirect co-culture system. Different DLBCL-derived exosomes could change the phenotype of macrophages through the STAT3 signaling, which upregulated the expression of oncogenic genes and classical markers of M2-like phenotype macrophages, such as IL-10, CD206, and CD163. The addition of DLBCL-derived exosomes resulted in the activation of the STAT3 signaling pathway of M0/M2 macrophages in an indirect co-culture system. GP130 was highly enriched in DLBCL-derived exosomes, which triggered the activation of STAT3 of macrophages and subsequently induced the downstream targets such as BCL2, SURVIVIN, and BAX. The parallel changes of STAT3 and GP130 in macrophages confirmed that GP130 of DLBCL-derived exosomes promoted macrophage polarization by activating STAT3 signaling. Furthermore, all of these effects could be reversed by the GP130 inhibitor SC144. The data indicated that DLBCL-derived exosomes could trigger macrophages polarization into a pro-survival M2-like phenotype, which was at least partially through the GP130/STAT3 signaling pathway. Collectively, this study showed that DLBCL-derived exosomes could promote macrophages transformation to protumor M2-like phenotype in the tumor microenvironment.

Characterization of mandarin fish (Siniperca chuatsi) IL-6 and IL-6 signal transducer and the association between their SNPs and resistance to ISKNV disease.

In fish, interleukin-6 (IL-6) is a very important immune-regulatory cytokine that plays a polyfunctional role in inflammation, metabolism, regeneration, and neural processes. IL-6 signal transducer (IL-6ST) is a specific receptor for IL-6 and expressed mainly in immune cells and hepatocytes. In this study, the complete cDNA and genomic DNA sequences of mandarin fish (Siniperca chuatsi) IL-6 and IL-6ST genes were identified and analyzed. Quantitative real-time PCR showed that IL-6 and IL-6ST were chiefly expressed in the immune organs. After challenge with infectious spleen and kidney necrosis virus (ISKNV), the expression levels of IL-6 were significantly up-regulated after 6 h and 24 h in the head kidney and spleen, respectively (p < 0.01), the peak value for both reached at 72 h, IL-6ST increased significantly after 120 h with a peak at 168 h in the head kidney (p < 0.01) and improved markedly at 168 h in the spleen (p < 0.01). Besides, IL-6 and IL-6ST have been identified 3 and 8 single nucleotide polymorphisms (SNPs), respectively. Statistical analysis showed that one SNP locus (1625C/T) in the coding region of IL-6 was significantly related to the resistance of mandarin fish against ISKNV. The 1625C→T locus in the coding region of IL-6 is a synonymous mutation; compared with the susceptible group, the frequency of allele T in the disease resistance group was significantly higher, which may be due to the rare codon produced by the mutation affecting translation. The involvement of IL-6 and IL-6ST in response to ISKNV infection in mandarin fish clearly indicate that the role of SNP markers in IL-6 was associated with the ISKNV resistance, which was demonstrated for the first time in our results. Thus, the current study may provide fundamental information for further breeding of mandarin fish with resistance to ISKNV infection.

Functional and structural analysis of cytokine-selective IL6ST defects that cause recessive hyper-IgE syndrome.

BACKGROUND: Biallelic variants in IL6ST, encoding GP130, cause a recessive form of hyper-IgE syndrome (HIES) characterized by high IgE level, eosinophilia, defective acute phase response, susceptibility to bacterial infections, and skeletal abnormalities due to cytokine-selective loss of function in GP130, with defective IL-6 and IL-11 and variable oncostatin M (OSM) and IL-27 levels but sparing leukemia inhibitory factor (LIF) signaling. OBJECTIVE: Our aim was to understand the functional and structural impact of recessive HIES-associated IL6ST variants. METHODS: We investigated a patient with HIES by using exome, genome, and RNA sequencing. Functional assays assessed IL-6, IL-11, IL-27, OSM, LIF, CT-1, CLC, and CNTF signaling. Molecular dynamics simulations and structural modeling of GP130 cytokine receptor complexes were performed. RESULTS: We identified a patient with compound heterozygous novel missense variants in IL6ST (p.Ala517Pro and the exon-skipping null variant p.Gly484_Pro518delinsArg). The p.Ala517Pro variant resulted in a more profound IL-6- and IL-11-dominated signaling defect than did the previously identified recessive HIES IL6ST variants p.Asn404Tyr and p.Pro498Leu. Molecular dynamics simulations suggested that the p.Ala517Pro and p.Asn404Tyr variants result in increased flexibility of the extracellular membrane-proximal domains of GP130. We propose a structural model that explains the cytokine selectivity of pathogenic IL6ST variants that result in recessive HIES. The variants destabilized the conformation of the hexameric cytokine receptor complexes, whereas the trimeric LIF-GP130-LIFR complex remained stable through an additional membrane-proximal interaction. Deletion of this membrane-proximal interaction site in GP130 consequently caused additional defective LIF signaling and Stüve-Wiedemann syndrome. CONCLUSION: Our data provide a structural basis to understand clinical phenotypes in patients with IL6ST variants.

IL-6 is not Absolutely Essential for the Development of a TH17 Immune Response after an Aerosol Infection with Mycobacterium Tuberculosis H37rv.

Anti-inflammatory treatment of chronic inflammatory diseases often increases susceptibility to infectious diseases such as tuberculosis (TB). Since numerous chronic inflammatory and autoimmune diseases are mediated by interleukin (IL)-6-induced T helper (TH) 17 cells, a TH17-directed anti-inflammatory therapy may be preferable to an IL-12-dependent TH1 inhibition in order to avoid reactivation of latent infections. To assess, however, the risk of inhibition of IL-6-dependent TH17-mediated inflammation, we examined the TH17 immune response and the course of experimental TB in IL-6- and T-cell-specific gp130-deficient mice. Our study revealed that the absence of IL-6 or gp130 on T cells has only a minor effect on the development of antigen-specific TH1 and TH17 cells. Importantly, these gene-deficient mice were as capable as wild type mice to control mycobacterial infection. Together, in contrast to its key function for TH17 development in other inflammatory diseases, IL-6 plays an inferior role for the generation of TH17 immune responses during experimental TB.

Toll-Like Receptor 3 Deficiency Leads to Altered Immune Responses to Chlamydia trachomatis Infection in Human Oviduct Epithelial Cells.

Reproductive tract pathology caused by Chlamydia trachomatis infection is an important global cause of human infertility. To better understand the mechanisms associated with Chlamydia-induced genital tract pathogenesis in humans, we used CRISPR genome editing to disrupt Toll-like receptor 3 (TLR3) function in the human oviduct epithelial (hOE) cell line OE-E6/E7 in order to investigate the possible role(s) of TLR3 signaling in the immune response to Chlamydia Disruption of TLR3 function in these cells significantly diminished the Chlamydia-induced synthesis of several inflammation biomarkers, including interferon beta (IFN-ß), interleukin-6 (IL-6), interleukin-6 receptor alpha (IL-6Rα), soluble interleukin-6 receptor beta (sIL-6Rß, or gp130), IL-8, IL-20, IL-26, IL-34, soluble tumor necrosis factor receptor 1 (sTNF-R1), tumor necrosis factor ligand superfamily member 13B (TNFSF13B), matrix metalloproteinase 1 (MMP-1), MMP-2, and MMP-3. In contrast, the Chlamydia-induced synthesis of CCL5, IL-29 (IFN-λ1), and IL-28A (IFN-λ2) was significantly increased in TLR3-deficient hOE cells compared to their wild-type counterparts. Our results indicate a role for TLR3 signaling in limiting the genital tract fibrosis, scarring, and chronic inflammation often associated with human chlamydial disease. Interestingly, we saw that Chlamydia infection induced the production of biomarkers associated with persistence, tumor metastasis, and autoimmunity, such as soluble CD163 (sCD163), chitinase-3-like protein 1, osteopontin, and pentraxin-3, in hOE cells; however, their expression levels were significantly dysregulated in TLR3-deficient hOE cells. Finally, we demonstrate using hOE cells that TLR3 deficiency resulted in an increased amount of chlamydial lipopolysaccharide (LPS) within Chlamydia inclusions, which is suggestive that TLR3 deficiency leads to enhanced chlamydial replication and possibly increased genital tract pathogenesis during human infection.

Signaling Through gp130 Compromises Suppressive Function in Human FOXP3+ Regulatory T Cells.

The CD4+FOXP3+ regulatory T cell (Treg) subset is an indispensable mediator of immune tolerance. While high and stable expression of the transcription factor FOXP3 is considered a hallmark feature of Treg cells, our previous studies have demonstrated that the human FOXP3+ subset is functionally heterogeneous, whereby a sizeable proportion of FOXP3+ cells in healthy individuals have a diminished capacity to suppress the proliferation and cytokine production of responder cells. Notably, these non-suppressive cells are indistinguishable from suppressive Treg cells using conventional markers of human Treg. Here we investigate potential factors that underlie loss of suppressive function in human Treg cells. We show that high expression of the IL-6 family cytokine receptor subunit gp130 identifies Treg cells with reduced suppressive capacity ex vivo and in primary FOXP3+ clones. We further show that two gp130-signaling cytokines, IL-6 and IL-27, impair the suppressive capacity of human Treg cells. Finally, we show that gp130 signaling reduces the expression of the transcription factor Helios, whose expression is essential for stable Treg function. These results highlight the role of gp130 in regulating human Treg function, and suggest that modulation of gp130 signaling may serve as a potential avenue for the therapeutic manipulation of human Treg function.

The interleukin-6 regulates the function of monocytes/macrophages (MO/MФ) via the interleukin-6 receptor ß in ayu (Plecoglossus altivelis).

Interleukin-6 (IL-6) is one of the most pleiotropic cytokines because of its wide range of effects on cells of the immune and non-immune systems in the body. However, the role of IL-6 in fish monocytes/macrophages (MO/MФ) is poorly understood. In this study, we cloned the cDNA sequence of the IL-6 gene from ayu (Plecoglossus altivelis) and demonstrated using a tissue distribution assay that ayu interleukin-6 (PaIL-6) mRNA is expressed in all tested tissues. Changes in expression were observed in immune tissues as well as in MO/MФ after a Vibrio anguillarum infection; subsequently, PaIL-6 was expressed and purified to prepare anti-PaIL-6 antibodies. Recombinant PaIL-6 protein (rPaIL-6) treatment enhanced pro-inflammatory cytokine expression. Ayu interleukin-6 receptor ß (PaIL-6Rß) knockdown resulted in decreased pro-inflammatory cytokine expression in MO/MФ treated with rPaIL-6, whereas no significant changes were observed after ayu interleukin-6 receptor α (PaIL-6Rα) knockdown in MO/MФ. PaIL-6 and PaIL-6Rß knockdown in MO/MФ inhibited the phosphorylation of signal transducer and activator of transcription 1. Moreover, PaIL-6Rß knockdown inhibited the phagocytic and bactericidal ability of ayu MO/MФ treated with rPaIL-6. These data indicate that PaIL-6 may be able to regulate the function of ayu MO/MФ.

Interleukin-6 (IL-6) mediates protection against glucose toxicity in human Müller cells via activation of VEGF-A signaling.

Interleukin-6 (IL-6) has become a target of interest for drug development aiming to treat diabetic retinopathy. Since IL-6 signaling can promote beneficial as well as detrimental effects via two different signaling pathways, the objective of the present study was to investigate the effects of classical IL-6 and IL-6 trans-signaling on human Müller cells (HMC), which are important for the development of diabetic retinopathy. HMCs were cultured in normal (5 mmol/L) and high (25 mmol/L) glucose plus or minus IL-6 or IL-6/sIL-6R. IL-6 receptor expression using immunohistochemistry and flow cytometry and cytokine release using magnetic bead assays were determined. HMCs express the membrane bound form of the IL-6 receptor (mIL-6R), gp130, and can release the soluble forms sIL-6R and sgp130 demonstrating that HMCs are capable of responding to classical IL-6 and IL-6 trans-signaling. IL-6 protected HMCs from glucose toxicity via VEGF-A signaling. IL-6/sIL-6R caused only modest protection, which was not mediated by VEGF-A. Our data show for the first time that classical IL-6 signaling exerts its beneficial effects through VEGF-A action contrary to IL-6 trans-signaling, which was VEGF-A independent. These results have clinical implications for drug development targeting IL-6 since strict anti-IL-6 therapies might further decrease neuroretinal functions in the diabetic retina.

Activating mutations of the gp130/JAK/STAT pathway in human diseases.

Cytokines of the interleukin-6 (IL-6) family are involved in numerous physiological and pathophysiological processes. Dysregulated and increased activities of its members can be found in practically all human inflammatory diseases including cancer. All cytokines activate several intracellular signaling cascades, including the Jak/STAT, MAPK, PI3K, and Src/YAP signaling pathways. Additionally, several mutations in proteins involved in these signaling cascades have been identified in human patients, which render these proteins constitutively active and result in a hyperactivation of the signaling pathway. Interestingly, some of these mutations are associated with or even causative for distinct human diseases, making them interesting targets for therapy. This chapter describes the basic biology of the gp130/Jak/STAT pathway, summarizes what is known about the molecular mechanisms of the activating mutations, and gives an outlook how this knowledge can be exploited for targeted therapy in human diseases.

Targeting Interleukin-6 Signaling in Clinic.

Interleukin-6 (IL-6) is a pleiotropic cytokine with roles in immunity, tissue regeneration, and metabolism. Rapid production of IL-6 contributes to host defense during infection and tissue injury, but excessive synthesis of IL-6 and dysregulation of IL-6 receptor signaling is involved in disease pathology. Therapeutic agents targeting the IL-6 axis are effective in rheumatoid arthritis, and applications are being extended to other settings of acute and chronic inflammation. Recent studies reveal that selective blockade of different modes of IL-6 receptor signaling has different outcomes on disease pathology, suggesting novel strategies for therapeutic intervention. However, some inflammatory diseases do not seem to respond to IL-6 blockade. Here, we review the current state of IL-6-targeting approaches in the clinic and discuss how to apply the growing understanding of the immunobiology of IL-6 to clinical decisions.

Breast Cancer-Derived Exosomes Alter Macrophage Polarization via gp130/STAT3 Signaling.

Tumor-derived exosomes are being recognized as essential mediators of intercellular communication between cancer and immune cells. It is well established that bone marrow-derived macrophages (BMDMs) take up tumor-derived exosomes. However, the functional impact of these exosomes on macrophage phenotypes is controversial and not well studied. Here, we show that breast cancer-derived exosomes alter the phenotype of macrophages through the interleukin-6 (IL-6) receptor beta (glycoprotein 130, gp130)-STAT3 signaling pathway. Addition of breast cancer-derived exosomes to macrophages results in the activation of the IL-6 response pathway, including phosphorylation of the key downstream transcription factor STAT3. Exosomal gp130, which is highly enriched in cancer exosomes, triggers the secretion of IL-6 from BMDMs. Moreover, the exposure of BMDMs to cancer-derived exosomes triggers changes from a conventional toward a polarized phenotype often observed in tumor-associated macrophages. All of these effects can be inhibited through the addition of a gp130 inhibitor to cancer-derived exosomes or by blocking BMDMs exosome uptake. Collectively, this work demonstrates that breast cancer-derived exosomes are capable of inducing IL-6 secretion and a pro-survival phenotype in macrophages, partially via gp130/STAT3 signaling.

TRAF2 and TRAF5 associated with the signal transducing receptor gp130 limit IL-6-driven transphosphorylation of JAK1 through the inhibition of proximal JAK-JAK interaction.

Tumor necrosis factor receptor-associated factor 2 (TRAF2) and TRAF5 constitutively bind to glycoprotein 130 kDa (gp130) and inhibit IL-6-driven activation of signal transducer and activator of transcription 3 (STAT3) in CD4+ T cells, which limits the differentiation of pro-inflammatory IL-17-producing helper T cells that require IL-6-receptor (IL-6R) signals for their development. However, it is not known how the interaction between TRAF and gp130 negatively regulates STAT3 activity in the IL-6R complex. We hypothesized that TRAF proteins associated with gp130 might limit the activation of Janus kinase that is needed for the activation of STAT3. To test this, we transfected HEK293T cells to express gp130 and TRAF2 or TRAF5 together with two chimeric JAK1 proteins combined with either the N-terminal or the C-terminal protein fragment of firefly luciferase. Using this luciferase fragment complementation system, we found that the recovery of luciferase enzyme activity was coincident with proximal JAK1-JAK1 interaction and phosphorylation of JAK1 in the IL-6R complex and that the expression of TRAF protein significantly inhibited the recovery of luciferase activity. The binding of TRAF to gp130 via the C-terminal TRAF domain was essential for the inhibition. In accordance with this, upon stimulation of endogenous gp130 with a complex of IL-6 and IL-6R, Traf5-/- CD4+ T cells displayed significantly higher amounts of phosphorylated JAK1 than did their wild-type counterparts. Therefore, our results demonstrate that gp130-associated TRAF2 and TRAF5 inhibit the interaction between two JAK proteins in the IL-6R complex that is essential for initiating the JAK-STAT signaling pathway.

Interleukin-6 and insulin-like growth factor-1 synergistically promote the progression of NSCLC.

The signaling pathways of interleukin-6 (IL-6) and insulin-like growth factor 1 (IGF-1) play an important role in the progression of lung cancer, and this study aimed to explore whether they can synergistically promote the progression of non-small cell lung cancer (NSCLC). We found that IL-6, glycoprotein 130 (GP130), IGF-1 and IGF-1R were highly expressed in NSCLC (p = .000), and there was the correlation between GP130, IGF-1, and IGF-1R (p < .01). The overall survival of patients with the co-expression of GP130 and IGF-1R was significantly shorter (p = .0360). Co-stimulation of IL-6 and IGF-1 resulted in significantly enhanced in cell proliferation, (p < .05), invasion (p < .05), cycle (p < .05), apoptosis (p < .05), and the expression of signal molecules (GP130, IGF-1R, p-AKT, and p-ERK1/2) (all p < .05) in NSCLC cells. This experiment revealed that IL-6 and IGF-1 can synergistically promote the progression of NSCLC. The high expression of GP130 and IGF-1R is an independent risk factor for poor prognosis patients, and it is helpful to find a more accurate target for targeted therapy in NSCLC.

Multiple sclerosis treatment effects on plasma cytokine receptor levels.

Genetic variants within some cytokine receptor genes have been associated with MS susceptibility, including IL7RA and IL2RA. As these genes are expressed by cells targeted by immune-modulatory drugs, we explored the potential role of their gene products as biomarkers in monitoring MS treatment. We assessed the impact of natalizumab followed by fingolimod on the intra-individual changes of plasma protein levels of sIL-7Rα, sIL-2Rα and also sIL-6R and sgp130 in MS patients. During natalizumab treatment we observed a decline in sgp130 and sIL-7Rα levels, while subsequent fingolimod treatment lead to increased sgp130 and sIL-7Rα and decreased sIL-2Rα levels. In addition, during fingolimod treatment sIL-7Rα levels were increasing significantly more in patients homozygous for the MS risk genotype of rs6897932. We also observed an effect of the MS associated rs71624119 on sgp130 levels. These results may elucidate the pharmacodynamics of treatments and help identify biomarkers for MS outcomes.

Downregulation of genes related to immune and inflammatory response in IVF implantation failure cases under controlled ovarian stimulation.

PROBLEM: Implantation failure (IF) even after the good-quality embryo transfer (ET) is main obstacle in in vitro fertilization (IVF). We aim to study the genomics of endometrial receptivity in IF patients under controlled ovarian stimulation (COS) during which ET is generally practised in IVF. METHOD OF STUDY: Endometrial gene expression profiling in IF patients (n=10) and oocyte donors (n=8) were compared during window of implantation under COS by microarray. Enrichment analysis of microarray data was performed to determine dysregulated pathways. Microarray results were validated by real-time PCR. Localization of genes related to immune response (progestagen-associated endometrial protein (PAEP), leukaemia inhibitory factor (LIF), interleukin-6 signal transducer (IL6ST) was detected by immunohistochemistry. RESULTS: The gene ontology, pathway analysis and enrichment mapping revealed significant downregulation in activation and regulation of immune and inflammation response in IF patients under COS. The lower expression of PAEP, LIF and IL6ST in cases compared to controls by real time and immunohistochemistry suggests the functional importance of these genes. CONCLUSION: Importance of immune and inflammatory response in endometrial receptivity adds on to the current knowledge of gene expression profile in IF under COS. The panel of genes involved in these pathways would be useful in determining further line of treatment for IF during IVF.

Interleukin-11-driven gastric tumourigenesis is independent of trans-signalling.

Deregulated gp130-dependent STAT3 signalling by the pleiotropic cytokine interleukin (IL)-11 has been implicated in the pathogenesis of gastric cancer (GC), the third most common cancer worldwide. While the IL-11-gp130-STAT3 signalling axis has traditionally been thought to exclusively use the membrane-bound IL-11 receptor (mIL-11R), recent evidence suggests that mIL-11R can be proteolytically cleaved to generate a soluble form (sIL-11R) which can elicit trans-signalling. Since the role of IL-11 trans-signalling in disease pathogenesis is unknown, here we have employed the IL-11-driven gp130F/F spontaneous model of GC to determine whether IL-11 trans-signalling promotes gastric tumourigenesis. sIL-11R protein was detectable in gastric tissue from GC patients, and sIL-11R levels were elevated in tumours of gp130F/F mice compared to matched non-tumours. Among candidate proteases associated with the generation of sIL-11R, ADAM10 and the related metalloprotease ADAM17 were significantly upregulated in tumours of both gp130F/F mice and GC patients compared to matched non-tumour tissues. The genetic blockade of IL-11 trans-signalling in gp130F/F mice upon the transgenic over-expression of the trans-signalling antagonist, sgp130Fc, failed to suppress gastric inflammation and associated tumour growth, and also had no effect on reducing hyper-activated STAT3 levels. Furthermore, a non-essential role for ADAM17 in IL-11-driven gastric tumourigenesis was supported by the observation that the tumour burden was unaffected in gp130F/F:Adam17ex/ex mice in which ADAM17 expression levels have been substantially reduced. Collectively, these findings suggest that classic signalling rather than trans-signalling is the mode by which IL-11 promotes gastric tumourigenesis.

Crosstalk between different family members: IL27 recapitulates IFNγ responses in HCC cells, but is inhibited by IL6-type cytokines.

Interleukin-27 (IL27) is a type-I-cytokine of the IL6/IL12 family predominantly secreted by activated macrophages and dendritic cells. In the liver, IL27 expression was observed to be upregulated in patients with hepatitis B, and sera of hepatocellular carcinoma (HCC) patients contain significantly elevated levels of IL27 compared to healthy controls or patients with hepatitis and/or liver cirrhosis. In this study, we show that IL27 induces STAT1 and STAT3 phosphorylation in 5 HCC lines and 3 different types of non-transformed liver cells. We were especially interested in the relevance of the IL27-induced STAT3 activation in liver cells. Thus, we compared the IL27 responses with those induced by IFNγ (STAT1-dominated response) or IL6-type cytokines (IL6, hyper-IL6 (hy-IL6) or OSM) (STAT3-dominated response) by microarray analysis and find that in HCC cells, IL27 induces an IFNγ-like, STAT1-dependent transcriptional response, but we do not find an effective STAT3-dependent response. Validation experiments corroborate the finding from the microarray evaluation. Interestingly, the availability of STAT1 seems critical in the shaping of the IL27 response, as the siRNA knock-down of STAT1 revealed the ability of IL27 to induce the acute-phase protein γ-fibrinogen, a typical IL6 family characteristic. Moreover, we describe a crosstalk between the signaling of IL6-type cytokines and IL27: responses to the gp130-engaging cytokine IL27 (but not those to IFNs) can be inhibited by IL6-type cytokine pre-stimulation, likely by a SOCS3-mediated mechanism. Thus, IL27 recapitulates IFNγ responses in liver cells, but differs from IFNγ by its sensitivity to SOCS3 inhibition.

Colorectal cancer cell-derived interleukin-6 enhances the phagocytic capacity and migration of THP-1 cells.

Macrophages perform a versatile range of functions in response to environmental stimuli. In the present study, we evaluated whether interleukin-6 (IL-6), a cytokine released from colorectal cancer (CRC) cells and associated with CRC pathogenesis and metastasis, modulates the phagocytic capacity and migratory ability of macrophages, using a monocyte-macrophage THP-1 cell model and human peripheral monocytes. We found that CRC cells enhanced the phagocytic capacity and migration of THP-1 cells and human peripheral monocytes. CRC cell culture supernatants and recombinant IL-6 neutralized with anti-IL-6 and anti-gp130 antibodies considerably decreased IL-6-mediated phagocytosis by and migration of THP-1 cells and human peripheral monocytes, via the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Our data suggest that CRC cells secreting IL-6 via STAT3 phosphorylation can enhance the phagocytic capacity and migration of macrophages in the tumor microenvironment.

RBM3 regulates temperature sensitive miR-142-5p and miR-143 (thermomiRs), which target immune genes and control fever.

Fever is commonly used to diagnose disease and is consistently associated with increased mortality in critically ill patients. However, the molecular controls of elevated body temperature are poorly understood. We discovered that the expression of RNA-binding motif protein 3 (RBM3), known to respond to cold stress and to modulate microRNA (miRNA) expression, was reduced in 30 patients with fever, and in THP-1-derived macrophages maintained at a fever-like temperature (40 °C). Notably, RBM3 expression is reduced during fever whether or not infection is demonstrable. Reduced RBM3 expression resulted in increased expression of RBM3-targeted temperature-sensitive miRNAs, we termed thermomiRs. ThermomiRs such as miR-142-5p and miR-143 in turn target endogenous pyrogens including IL-6, IL6ST, TLR2, PGE2 and TNF to complete a negative feedback mechanism, which may be crucial to prevent pathological hyperthermia. Using normal PBMCs that were exogenously exposed to fever-like temperature (40 °C), we further demonstrate the trend by which decreased levels of RBM3 were associated with increased levels of miR-142-5p and miR-143 and vice versa over a 24 h time course. Collectively, our results indicate the existence of a negative feedback loop that regulates fever via reduced RBM3 levels and increased expression of miR-142-5p and miR-143.

EBI3 Downregulation Contributes to Type I Collagen Overexpression in Scleroderma Skin.

IL-12 family cytokines are implicated in the pathogenesis of various autoimmune diseases, but their role in the regulation of extracellular matrix expression and its contribution to the phenotype of systemic sclerosis (SSc) remain to be elucidated. Among the IL-12 family members, IL-35 decreases type I collagen expression in cultured dermal fibroblasts. IL-35 consists of p35 and EBI3 subunits, and EBI3 alone could downregulate the protein and mRNA expression of type I or type III collagen in the presence or absence of TGF-ß costimulation. We found that collagen mRNA stability was reduced by EBI3 via the induction of miR-4500. The IL-35 levels in the sera or on the surface of T cells were not altered in SSc patients, while EBI3 expression was decreased in the keratinocytes of the epidermis and regulatory T cells of the dermis in SSc skin compared with normal skin, which may induce collagen synthesis in SSc dermal fibroblasts. We also found that gp130, the EBI3 receptor, was expressed in both normal and SSc fibroblasts. Moreover, we revealed that EBI3 supplementation by injection into the skin improves mice skin fibrosis. Decreased EBI3 in SSc skin may contribute to an increase in collagen accumulation and skin fibrosis. Clarifying the mechanism regulating the extracellular matrix expression by EBI3 in SSc skin may lead to better understanding of this disease and new therapeutic strategies using ointment or microinjection of the subunit.