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New ways of developing treatment of chronic inflammation
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August 30, 2019
Researchers have found a new way to treat the inflammation involved in chronic diseases such as psoriasis, asthma and HIV. A group of transmitter substances (cytokines) in the immune system, the so-called IL-1 family, has been shown to play an important role in many of these diseases by regulating the body's immune responses.
[In summary, blocking IL-1R3 is a therapy to limit activities from six members of the IL-1 family. With a broad applicability and specific targeting, this offers a feasible treatment option with an extensive therapeutic range.]
Researchers from Aarhus University Hospital and Aarhus University in Denmark in collaboration with researchers from Colorado in the United States have found a new way to treat the inflammation involved in chronic diseases such as psoriasis, asthma and HIV.
A group of transmitter substances (cytokines) in the immune system, the so-called IL-1 family, has been shown to play an important role in many of these diseases by regulating the body's immune responses.
Professor Charles A. Dinarello from University of Colorado Denver is also an honorary doctor at Aarhus University. He is an expert in regulation and transmission of these cytokines. He is primarily known for discovering the important cytokine IL-1(-β), which plays an important role in countless diseases. In collaboration with Charles Dinarello, the Danish researchers have investigated a more efficient way of reducing the effect of the IL-1 family and in this way improve treatment of chronic inflammatory diseases.
Previous research has often focused on blocking a single cytokine or signaling pathway at a time. However, many diseases and sequela are driven by more than one cytokine. This has caused researchers to wonder if it could be possible to block more important signaling pathways of the IL-1 family at the same time, and in this way make it possible to develop better treatments. The researchers try to find a broader anti-inflammatory treatment impacting several important cytokines at the same time, but also trying to avoid that this causes unintended side-effects.
In this study, the researchers have investigated if a receptor (IL-1R3), which is not just involved in the signaling of one but six different inflammatory cytokines in the IL-1 family, could be a possible target in the treatment of chronic inflammatory disease. Using an antibody to block the effect of IL-1R3, it was possible for the researchers to investigate the effects in both studies on cells and mice.
In this way, researchers could study some of the consequences of the blocking of this receptor on the immune system. At the same time, the researchers specifically studied the effect of blocking IL-1R3 in mice with either gout, acute allergic inflammation (asthma) or psoriasis.
"The experiments showed that it was possible to effectively block the receptor and reduce manifestation of diseases, which underlines the potentials in our new approach," says MD and PhD Jesper Falkesgaard Højen.
"Even though new questions arise as a consequences of these results, we have managed to describe a new and effective approach to block IL-1 family driven inflammation, and in this way we have possibly contributed with a new direction to study and treat chronic inflammatory conditions driven by the IL-1 family."
https://www.sciencedaily.com/releases/2019/08/190830112817.htm
our hypothesis was that blocking IL-1R3 could reduce both the specific cytokine of a disease, for example IL-33 in asthma, as well as the associated dysregulated IL-1 component driving basal inflammation, contributing not only to the disease phenotype, but also to the development of comorbidities.
In the present study, we addressed responses specific for IL-1, IL-33 and the IL-36 subfamily, and found that blocking IL-1R3 was highly effective in models of peritonitis, allergic airway inflammation and psoriasis. In each of these models, there was an inflammatory component from either IL-1β or IL-1α. In the case of MSU peritonitis, IL-1β was the primary disease-driving cytokine. In asthma or psoriasis, inflammation from IL-1 worsens the severity of the disease manifestation.
IL-1R3 blockade broadly attenuates the functions of six members of the IL-1 family, revealing their contribution to models of disease
In summary, blocking IL-1R3 is a therapy to limit activities from six members of the IL-1 family. With a broad applicability and specific targeting, this offers a feasible treatment option with an extensive therapeutic range.
Nature Immunology Aug 19 2019
Jesper Falkesgaard Højen 1,2,3, Marie Louise Vindvad Kristensen3, Amy S. McKee3,4,Megan Taylor Wade3, Tania Azam3, Lars P. Lunding5, Dennis M. de Graaf3,6, Benjamin J. Swartzwelter3, Michael Wegmann5, Martin Tolstrup 1,2, Karsten Beckman7, Mayumi Fujita4,8, Stephan Fischer7 and Charles A. Dinarello 3,6*
Abstract
Interleukin (IL)-1R3 is the co-receptor in three signaling pathways that involve six cytokines of the IL-1 family (IL-1α, IL-1β, IL-33, IL-36α, IL-36β and IL-36γ). In many diseases, multiple cytokines contribute to disease pathogenesis. For example, in asthma, both IL-33 and IL-1 are of major importance, as are IL-36 and IL-1 in psoriasis. We developed a blocking monoclonal antibody (mAb) to human IL-1R3 (MAB-hR3) and demonstrate here that this antibody specifically inhibits signaling via IL-1, IL-33 and IL-36 in vitro. Also, in three distinct in vivo models of disease (crystal-induced peritonitis, allergic airway inflammation and psoriasis), we found that targeting IL-1R3 with a single mAb to mouse IL-1R3 (MAB-mR3) significantly attenuated heterogeneous cytokine-driven inflammation and disease severity. We conclude that in diseases driven by multiple cytokines, a single antagonistic agent such as a mAb to IL-1R3 is a therapeutic option with considerable translational benefit.
Inhibition of cytokine function is a cornerstone of many clinical interventions. Although treatment often focuses on blocking either a single ligand or its primary receptor1, targeting a single cytokine can imply that a disease is due to a distinct mediator. However, this is not always the case. The heterogeneous nature of inflammatory diseases may explain less than optimal outcomes or failures in clinical trials when neutralizing only a single cytokine, in particular, when preclinical models reveal synergy of two cytokines. Diseases where more than one IL-1 family member has been attributed a prominent role, such as IL-1β and IL-33 in asthma2,3 and IL-1α and IL-36 in psoriasis4,5, this heterogeneity. Because there is a basal inflammatory component in most diseases, blockade of the specific disease-driving cytokine as well as the inflammatory component would therefore probably improve outcomes.
The IL-1 family consists of 11 members, with a role in innate inflammation and acquired immunity6. In the search for an improved druggable target in the IL-1 family, we assessed possible interventional sites. The receptor family consists of ten members and one binding protein (IL-18BP)7. Of these, IL-1R1 binds IL-1α and IL-1β, recruiting IL-1R3 to form the trimeric signaling complex. IL-1R4 (ST2) binds IL-33 and forms a trimeric complex with IL-1R3, and IL-1R6 binds IL-36α, IL-36β and IL-36γ, similarly recruiting IL-1R3. In each case, IL-1R3 is the co-receptor that allows for the dimerization of the cytoplasmic Toll/IL-1R domains, triggering a unique response8,9. With IL-1R3 being the signaling regulator for six different cytokines, there are IL-1R3-dependent cytokines inducing inflammation, a type 1 helper T cell (TH1) response, a type 2 helper T cell (TH2) response or a combination of inflammation with either TH1 or TH2 responses. Blocking a common co-receptor, rather than individual primary receptors or ligands, may therefore provide a new mode of action for reducing associated diseases.
We describe here a fully humanized blocking mAb targeting human IL-1R3 (MAB-hR3), with an incorporated Fc-LALA (L234A/L235A) substitution to prevent the triggering of FcγRs10,11. We determined direct in vitro inhibition of signaling through IL-1R1, IL-1R4 and IL-1R6 by this mAb and investigated the inflammatory contribution of the IL-1R3 signaling-associated cytokines. Additionally, we conducted proof-of-concept in vivo studies using a mouse IL-1R3 mAb (MAB-mR3) in models of IL-1β-dependent monosodium urate crystal (MSU) peritonitis, IL-33-dependent ovalbumin (OVA) allergic airway inflammation and IL-36-dependent imiquimod (IMQ)-induced psoriasis. In each case, IL-1R3 blockade proved effective in attenuating the disease phenotypes.
Discussion
Dysregulation of the innate immune system takes place in atherosclerosis, autoimmune diseases, Alzheimer's disease and cancer27,28,29,30. For example, a global trial of 10,000 patients at risk for a second heart attack or stroke revealed that specific neutralization of IL-1β reduced both atherosclerosis and heart failure, but also the incidence and survival of cancer31,32. Thus, innate inflammation can be reduced by lowering the level of IL-1β. Accordingly, our hypothesis was that blocking IL-1R3 could reduce both the specific cytokine of a disease, for example IL-33 in asthma, as well as the associated dysregulated IL-1 component driving basal inflammation, contributing not only to the disease phenotype, but also to the development of comorbidities.
In the present study, we addressed responses specific for IL-1, IL-33 and the IL-36 subfamily, and found that blocking IL-1R3 was highly effective in models of peritonitis, allergic airway inflammation and psoriasis. In each of these models, there was an inflammatory component from either IL-1β or IL-1α. In the case of MSU peritonitis, IL-1β was the primary disease-driving cytokine. In asthma or psoriasis, inflammation from IL-1 worsens the severity of the disease manifestation.
The initial in vitro data supported the rationale for examining the broad effects of IL-1R3 blockade in vivo. Since MSU-induced inflammation is primarily driven by IL-1β, IL-1Ra was used as the positive control for efficient IL-1R1 inhibition. Despite using a fourfold higher molar dose of IL-1Ra compared to MAB-mR3, blocking IL-1R3 provided an additional level of protection. We speculate that blockade of the alarmin effects of IL-33 in barrier cells33, such as the peritoneal lining, might be of importance. IL-33 is traditionally known to induce TH2-dominated inflammation. However, in both the peritoneal cavity and in the skin, IL-33 induces a predominant neutrophil milieu as observed here34,35.
Caspase-1 inhibition can similarly be effective in MSU models20. However, extracellular cleavage of the IL-1β precursor by neutrophilic elastase and proteinase 3 can result in generation of active mature IL-1β36,37. Thus blocking IL-1 receptors is probably superior in diseases such as neutrophil-predominant arthritis, where elastase contributes substantially to IL-1β-driven inflammation37. In our MSU model, we observed a significant decrease in both granulocyte influx as well as elastase production when blocking IL-1R3 using MAB-mR3.
We next compared the effects of IL-1R3 blockade with that of specific IL-1R4 or IL-1R6 blockade. Here, we observed that TH1 responses driven by IL-33 or IL-36 cytokines could be reduced by IL-1R3 blockade. Secondly, that blocking IL-1R3 had a broader anti-inflammatory effect compared to isolated IL-33 or IL-36 signaling inhibition, findings that were recapitulated when investigating the differences between IL-1R1 and IL-1R3 blockade using two-way MLRs. For that reason, we found cause to exploit the IL-1R3 blockade in diseases influenced by multiple IL-1 family members. For instance the highly IL-33-dependent OVA-induced allergic asthma model38, as well as in the IL-36-dependent IMQ-induced psoriasis model39.
In the airways, IL-33 promotes a TH2 response, attracting eosinophils and basophils. MAB-mR3 treatment significantly reduced cell influx into the airways, primarily due to a marked decrease in eosinophils that are important in allergen-triggered airway inflammation40. We also observed a decrease in the levels of neutrophils, similar to the decrease observed in the MSU model. It is likely that the decrease in CXCL-1 (equivalent to human IL-8) could account for the lower numbers of neutrophils, as it is consistent with the known IL-8 induction in human airway goblet cells by IL-33 (ref. 41). Thus, decreasing airway inflammation by inhibition of both IL-1- and IL-33-induced IL-8 production, could be more effective than IL-33 blockade alone in allergic asthma, supporting IL-1R3 blockade. Consistent with these observations was a significant improvement of airway resistance to MCh challenge, revealing clear functional consequences of the anti-inflammatory intervention.
The IMQ model is similarly dependent not only on IL-36, but also on IL-1 and IL-8, making this disease similarly attractive for IL-1R3 blockade24,42,43. In our study, MAB-mR3 significantly attenuated visual signs of the disease, that is disease severity. And like the previously observed reduction of neutrophils by MAB-mR3, we also observed significantly lower numbers of circulating neutrophils as well as decreased levels of the neutrophil activation marker, MPO, in the skin. In fact, visual scoring correlated to levels of skin MPO. Remarkably there was a highly significant reduction of both IL-17a, IL-17f and IL-22 expression. These cytokines each possess an important role in the pathogenesis of psoriasis44, particularly for IL-22 where human mast cells produce large amounts of IL-2245. The observation that IL-1R3 blockade can inhibit the transcription of these cytokines supports a role for IL-1R3 targeting in psoriasis.
Although IL-1R3 is the co-receptor for ligand binding receptors of six different cytokines, IL-1R3 is not the only co-receptor shared by multiple cytokines. In fact, both the common γ chain (IL-2Rγ) and glycoprotein 130 (gp130 or IL-6ST (signal transducer)) are also required for the signaling of multiple cytokines. However, mice deficient of IL-2Rγ or gp130 have developmental abnormalities such as leukocyte production (IL-2Rγ) and organ development (gp130), respectively46,47. In contrast, IL-1R3-deficient mice display no signs of anatomic abnormalities and remain fully fertile48. Still, suppressing multiple signaling pathways could reduce the potential to mount an innate immune response, increasing frequencies of infections and impacting the development of helper T cells, such as TH1, TH2 and TH17. However, compared to using monotherapy such as anti-IL-33, using a lower dose of anti-IL-1R3 could still allow for a basic level of signaling through the primary pathways and remain disease suppressive. Considering the synergism between cytokines of the IL-1 family, reducing signaling in this family by IL-1R3 blockade, could more easily revert a vicious cycle, than intervening in multiple unrelated pathways. Thus, future research needs to address these concerns and considerations.
In summary, blocking IL-1R3 is a therapy to limit activities from six members of the IL-1 family. With a broad applicability and specific targeting, this offers a feasible treatment option with an extensive therapeutic range.
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