Soluble glycoprotein 130 (gp130) attenuates OSM- and LIF-induced cartilage proteoglycan catabolism

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

Nonspecific Inhibition of IL6 Family Cytokine Signalling by Soluble gp130

IL6 is a proinflammatory cytokine that binds to membrane-bound IL6 receptor (IL6R) or soluble IL6R to signal via gp130 in cis or trans, respectively. We tested the hypothesis that sgp130Fc, which is believed to be a selective IL6 trans-signalling inhibitor, is in fact a non-specific inhibitor of gp130 signalling. In human cancer and primary cells, sgp130Fc inhibited IL6, IL11, OSM and CT1 cis-signalling. The IC50 values of sgp130Fc for IL6 and OSM cis-signalling were markedly (20- to 200-fold) lower than the concentrations of sgp130Fc used in mouse studies and clinical trials. sgp130 inhibited IL6 and OSM signalling in the presence of an ADAM10/17 inhibitor and the absence of soluble IL6R or OSMR, with effects that were indistinguishable from those of a gp130 neutralising antibody. These data show that sgp130Fc does not exclusively block IL6 trans-signalling and reveal instead that broad inhibition of gp130 signalling likely underlies its therapeutic effects. This proposes global or modular inhibition of gp130 as a therapeutic approach for treating human disease.

Pleiotropic, Unique and Shared Responses Elicited by IL-6 Family Cytokines in Human Vascular Endothelial Cells

Vascular endothelial cells express glycoprotein 130 (gp130), which is utilized as a signaling receptor by cytokines in the interleukin-6 (IL-6) family. Several IL-6 family cytokines can be found in the circulatory system during physiological or pathological conditions, and may influence endothelial function and response. This study evaluated and compared the cellular and molecular responses induced by IL-6 family cytokines in human endothelial cells. A proteomic analysis showed that IL-6 family cytokines induce the release of a range of proteins from endothelial cells, such as C-C motif chemokine ligand 23, hepatocyte growth factor, and IL-6. Pathway analysis indicated that gp130-signaling in endothelial cells regulates several functions related to angiogenesis and immune cell recruitment. The present investigation also disclosed differences and similarities between different IL-6 family cytokines in their ability to induce protein release and regulate gene expression and intracellular signaling, in regards to which oncostatin M showed the most pronounced effect. Further, this study showed that soluble gp130 preferentially blocks trans-signaling-induced responses, but does not affect responses induced by classic signaling. In conclusion, IL-6 family cytokines induce both specific and overlapping molecular responses in endothelial cells, and regulate genes and proteins involved in angiogenesis and immune cell recruitment.

Exclusive inhibition of IL-6 trans-signaling by soluble gp130FlyRFc

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A variety of sgp130Fc muteins was generated.

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Introduction of a gp130 SNP (R281Q) into sgp130Fc increases IL-6 specificity.

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The sgp130Fc variant sgp130^FlyR exclusively affects IL-6 trans-signaling.

gp130 is the signal-transducing receptor for the Interleukin (IL)-6 type cytokines IL-6 and IL-11. To induce signaling, IL-6 forms a complex with IL-6 receptor (IL-6R) and IL-11 with IL-11 receptor (IL-11R). Membrane-bound IL-6R and IL-11R in complex with gp130 and the cytokine mediate classic-signaling, whereas trans-signaling needs soluble IL-6R and IL-11R variants. Interleukin (IL)-6 trans-signaling is of particular importance because it drives the development of autoimmune diseases, including rheumatoid arthritis and chronic inflammatory bowel diseases, whereas a role for IL-11 trans-signaling remains elusive. Soluble gp130 selectively inhibits trans-signaling of IL-6 whereas both, classic- and trans-signaling are abrogated by IL-6- and IL-6R-antibodies. Recently, we described an optimized sgp130 variant, which carries three amino acid substitutions T102Y/Q113F/N114L (sgp130^FlyFc) resulting in reduced inhibition of IL-11 trans-signaling by increasing the affinity of sgp130 for the site I of IL-6. Moreover, we described that the patient mutation R281Q in gp130 results in reduced IL-11 signaling. Here, we show that the combination of T102Y/Q113F/N114L and R281Q in the new variant sgp130^FlyRFc results in complete preservation of IL-11 mediated trans-signaling, whereas inhibition of IL-6 trans-signaling is maintained. Since sgp130Fc (olamkicept) has successfully completed a phase IIa trial in Crohn’s disease (CD) and ulcerative colitis, sgp130^FlyRFc might serve as second-generation therapeutic to diminish IL-11 trans-signaling cross-reactivity.

Selective inhibition of IL-6 trans-signaling by a miniaturized, optimized chimeric soluble gp130 inhibits TH17 cell expansion

The cytokine interleukin-6 (IL-6) signals through three mechanisms called classic signaling, trans-signaling, and trans-presentation. IL-6 trans-signaling is distinctly mediated through a soluble form of its transmembrane receptor IL-6R (sIL-6R) and the coreceptor gp130 and is implicated in multiple autoimmune diseases. Although a soluble form of gp130 (sgp130) inhibits only IL-6 trans-signaling, it also blocks an analogous trans-signaling mechanism of IL-11 and its soluble receptor sIL-11R. Here, we report miniaturized chimeric soluble gp130 variants that efficiently trap IL-6:sIL-6R but not IL-11:sIL-11R complexes. We designed a novel IL-6 trans-signaling trap by fusing a miniaturized sgp130 variant to an IL-6:sIL-6R complex-binding nanobody and the Fc portion of immunoglobulin G (IgG). This trap, called cs-130Fc, exhibited improved inhibition of as well as increased selectivity for IL-6 trans-signaling compared to the conventional fusion protein sgp130Fc. We introduced affinity-enhancing mutations in cs-130Fc and sgp130Fc that further improved selectivity toward IL-6 trans-signaling. Moreover, cs-130Fc efficiently inhibited the expansion of T helper 17 (TH17) cells in cultures of mouse CD4+ T cells treated with IL-6:sIL-6R. Thus, these variants may provide or lead to the development of more precisely targeted therapeutics for inflammatory disorders associated with IL-6 trans-signaling.

Upregulation of circulating inflammatory biomarkers under the influence of periodontal disease in rheumatoid arthritis patients

OBJECTIVES

Periodontal disease (PD) and rheumatoid arthritis (RA) are chronic immuno-inflammatory conditions with osteolysis being a hallmark feature. The influence of PD on RA's systemic inflammatory status and disease activity remains unclear. The objective of this study was to assess the systemic inflammation and disease activity of RA under the influence of PD.

METHODS

In this case-control study, 38 RA patients (19 with PD and 19 without PD) were compared to 38 non-RA patients and 12 healthy controls. Periodontal parameters (bleeding on probing (BOP), probing pocket depth (PPD), PPD Total, PPD Disease and marginal bone loss (MBL) were determined. Serological analyses included quantification of 92 inflammatory biomarkers using a multiplex proximity extension assay, anti-citrullinated protein antibodies (ACPA), rheumatoid factor (IgM-RF) and erythrocyte sedimentation rate (ESR). RA disease activity was determined using Disease Activity Score for 28 joints (DAS28). All RA patients were on medication.

RESULTS

IgM-RF was higher in RA patients with PD. PD conditions were more severe in the non-RA group. Inflammatory biomarkers (IL-10RB, IL-18, CSF-1, NT-3, TRAIL, PD-L1, LIF-R, SLAMF1, FGF-19, TRANCE, CST5, STAMPB, SIRT2, TWEAK, CX3CL1, CXCL5, MCP-1) were significantly higher in RA patients with PD than RA without PD. DAS28 associated with twice as many inflammatory biomarkers in RA patients with PD whereas IgM-RF and ACPA associated more frequently with biomarkers in the RA without PD group. IgM-RF correlated inversely with BOP.

CONCLUSION

Periodontal disease augments systemic inflammation in RA. A profound influence exists independent of autoimmune status.

Drug-induced modulation of gp130 signalling prevents articular cartilage degeneration and promotes repair

OBJECTIVE

Human adult articular cartilage (AC) has little capacity for repair, and joint surface injuries often result in osteoarthritis (OA), characterised by loss of matrix, hypertrophy and chondrocyte apoptosis. Inflammation mediated by interleukin (IL)-6 family cytokines has been identified as a critical driver of proarthritic changes in mouse and human joints, resulting in a feed-forward process driving expression of matrix degrading enzymes and IL-6 itself. Here we show that signalling through glycoprotein 130 (gp130), the common receptor for IL-6 family cytokines, can have both context-specific and cytokine-specific effects on articular chondrocytes and that a small molecule gp130 modulator can bias signalling towards anti-inflammatory and antidegenerative outputs.

METHODS

High throughput screening of 170 000 compounds identified a small molecule gp130 modulator termed regulator of cartilage growth and differentiation (RCGD 423) that promotes atypical homodimeric signalling in the absence of cytokine ligands, driving transient increases in MYC and pSTAT3 while suppressing oncostatin M- and IL-6-mediated activation of ERK and NF-κB via direct competition for gp130 occupancy.

RESULTS

This small molecule increased proliferation while reducing apoptosis and hypertrophic responses in adult chondrocytes in vitro. In a rat partial meniscectomy model, RCGD 423 greatly reduced chondrocyte hypertrophy, loss and degeneration while increasing chondrocyte proliferation beyond that observed in response to injury. Moreover, RCGD 423 improved cartilage healing in a rat full-thickness osteochondral defect model, increasing proliferation of mesenchymal cells in the defect and also inhibiting breakdown of cartilage matrix in de novo generated cartilage.

CONCLUSION

These results identify a novel strategy for AC remediation via small molecule-mediated modulation of gp130 signalling.

Interleukin-6 Signaling Pathway and Its Role in Kidney Disease: An Update

Interleukin-6 (IL-6) is a pleiotropic cytokine that not only regulates the immune and inflammatory response but also affects hematopoiesis, metabolism, and organ development. IL-6 can simultaneously elicit distinct or even contradictory physiopathological processes, which is likely discriminated by the cascades of signaling pathway, termed classic and trans-signaling. Besides playing several important physiological roles, dysregulated IL-6 has been demonstrated to underlie a number of autoimmune and inflammatory diseases, metabolic abnormalities, and malignancies. This review provides an overview of basic concept of IL-6 signaling pathway as well as the interplay between IL-6 and renal-resident cells, including podocytes, mesangial cells, endothelial cells, and tubular epithelial cells. Additionally, we summarize the roles of IL-6 in several renal diseases, such as IgA nephropathy, lupus nephritis, diabetic nephropathy, acute kidney injury, and chronic kidney disease.

The pro- and anti-inflammatory properties of the cytokine interleukin-6

Interleukin-6 is a cytokine not only involved in inflammation and infection responses but also in the regulation of metabolic, regenerative, and neural processes. In classic signaling, interleukin-6 stimulates target cells via a membrane bound interleukin-6 receptor, which upon ligand binding associates with the signaling receptor protein gp130. Gp130 dimerizes, leading to the activation of Janus kinases and subsequent phosphorylation of tyrosine residues within the cytoplasmic portion of gp130. This leads to the engagement of phosphatase Src homology domains containing tyrosin phosphatase-2 (SHP-2) and activation of the ras/raf/Mitogen-activated protein (MAP) kinase (MAPK) pathway. In addition, signal transducer and activator of transcription factors are recruited, which are phosphorylated, and consequently dimerize whereupon they translocate into the nucleus and activate target genes. Interestingly, only few cells express membrane bound interleukin-6 receptor whereas all cells display gp130 on the cell surface. While cells, which only express gp130, are not responsive to interleukin-6 alone, they can respond to a complex of interleukin-6 bound to a naturally occurring soluble form of the interleukin-6 receptor. Therefore, the generation of soluble form of the interleukin-6 receptor dramatically enlarges the spectrum of interleukin-6 target cells. This process has been named trans-signaling. Here, we review the involvement of both signaling modes in the biology of interleukin-6. It turns out that regenerative or anti-inflammatory activities of interleukin-6 are mediated by classic signaling whereas pro-inflammatory responses of interleukin-6 are rather mediated by trans-signaling. This is important since therapeutic blockade of interleukin-6 by the neutralizing anti-interleukin-6 receptor monoclonal antibody tocilizumab has recently been approved for the treatment of inflammatory diseases. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.

Functional expression of a biologically active fragment of soluble gp130 as an ELP-fusion protein in transgenic plants: purification via inverse transition cycling

In murine models of Crohn's disease, rheumatoid arthritis and colon cancer, IL-6 (interleukin-6) signalling via the sIL-6R (soluble IL-6 receptor; termed IL-6 trans-signalling) has been shown to promote the pathology associated with these conditions. These detrimental activities can, however, be selectively blocked by soluble forms of the gp130 (glycoprotein 130) receptor. Although sgp130 (soluble gp130) therefore represents a viable therapeutic modality for the treatment of these conditions, the mass manufacture of such biologics is often expensive. The advent of molecular farming has, however, provided an extremely cost-effective strategy for the engineering of recombinant proteins. Here, we describe the expression and production of a biologically active sgp130 variant that is expressed in transgenic tobacco plants as an ELP (elastin-like peptide)-fusion protein (mini-gp130-ELP). Mini-gp130-ELP consists of the first three domains of gp130 (Ig-like domain and cytokine binding module) fused to 100 repeats of ELP. Expression of mini-gp130-ELP did not affect the growth rate or morphology of the transgenic plants, and purification was achieved using inverse transition cycling. This approach led to an overall yield of 141 microg of purified protein per g of fresh leaf weight. The purified mini-gp130-ELP specifically inhibited sIL-6R-mediated trans-signalling as measured by binding to the IL-6-sIL-6R complex and through its ability to block sIL-6R-mediated activation of STAT3 (signal transducer and activator of transcription 3) phosphorylation and proliferation in human hepatoma cells and murine pre-B-cells. Consequently, the present study validates the potential application of molecular farming in transgenic tobacco plants as a strategy for the expression and purification of therapeutically advantageous biologics such as sgp130.

Characterization of the leukemia inhibitory factor receptor in the goldfish (Carassius auratus)

The cytokine leukemia inhibitory factor (LIF) and its receptor LIFR have been extensively characterized in mammals. LIF has been shown to mediate the proliferation, differentiation and activation of a number of cell types in various tissues. This paper reports on the identification of a novel LIFR isolated from goldfish (Carassius auratus) macrophages. Goldfish LIFR shares a 26% amino acid sequence identity with mammalian LIFR sequences; however it retains all of the conserved amino acid motifs that identify a functional LIFR such as the cytokine binding domains and the box-1 and box-2 motifs. The goldfish LIFR phylogenetically groups with the other identified LIFRs from human, mouse, rat and chicken, and it appears to be ancestral to the divergence of the oncostatin M receptor (OSMR). The tissue expression of goldfish LIFR is observed in the gill, kidney and brain as well as sorted goldfish macrophages which exhibit higher expression than monocytes and early progenitor cells.