From supernatants to cytokines: a personal view on the early history of IL-1, IL-1Ra, TNF and its inhibitor in rheumatology

Monotropein synergizes with methotrexate to attenuate synovial inflammation in adjuvant-induced arthritis mice and fibroblast-like synoviocyte via GSK-3β

BACKGROUND

Methotrexate (MTX) is the preferred drug for the treatment of rheumatoid arthritis (RA), but the toxic effects of long-term use limited its widespread clinical practice. The combination therapy of MTX with natural products is an effective strategy to reduce the toxic effects of MTX and enhance the therapeutic efficacy. Monotropein (MON), an iridoid glycosides, has potential therapeutic effects in inflammatory bone loss and osteoarthritis, and liver injury caused by MTX. However, whether MON can increase the therapeutic effects of MTX on RA and the related mechanism is not clear.

PURPOSE

This study aimed to clarify the MON enhancement on MTX in the treatment of RA, and also explore the target and mechanism of MON in anti-RA.

METHODS

The adjuvant-induced arthritis (AA) mice and RA-fibroblast-like synoviocytes (RA-FLSs) were used to evaluate the alleviating effects of MON, MTX and their combination on RA. The network pharmacology analysis, molecular docking and surface plasmon resonance (SPR) were utilized to predict the potential therapeutic targets and mechanism of MON on RA. The interference RNA was used to knockdown the target gene in TNF-α-stimulated FLSs and AA mice to validate the mechanism of MON on RA.

RESULTS

MON synergizes with MTX to suppress synovial inflammation in AA mice and inhibit TNF-α-induced FLSs proliferation, migration, inflammatory factors production, as well as the activation of NF-κB and JAK2/STAT3 signaling pathways. Network pharmacology predicted GSK-3β as a potential target of MON, and the molecular docking, CETSA, and SPR assays exhibited that MON had a good affinity with GSK-3β. Furthermore, GSK-3β knockdown suppressed TNF-α-induced FLSs proliferation, migration, matrix metalloproteinase 2 (MMP2) and MMP3 expression, and the activation of NF-κB and STAT3 signaling, while MON lost its inhibitory effects in GSK-3β knockdown FLSs. In addition, joint tissue-specific GSK-3β knockdown in AA mice alleviated synovial inflammation, decreased paw swelling and arthritis score, suppressed the phosphorylation of p65 and STAT3 of joint tissue in AA mice, while MON lost efficacy in GSK-3β-knockdown mice.

CONCLUSION

MON synergizes with MTX to inhibit synovial inflammation in AA mice and RA-FLSs inflammation by targeting GSK-3β to suppress NF-κB and STAT3 pathways.

Rheumatoid arthritis: the old issue, the new therapeutic approach

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease of unknown etiology. The most common form of this disease is chronic inflammatory arthritis, which begins with inflammation of the synovial membrane of the affected joints and eventually leads to disability of the affected limb. Despite significant advances in RA pharmaceutical therapies and the availability of a variety of medicines on the market, none of the available medicinal therapies has been able to completely cure the disease. In addition, a significant percentage (30-40%) of patients do not respond appropriately to any of the available medicines. Recently, mesenchymal stromal cells (MSCs) have shown promising results in controlling inflammatory and autoimmune diseases, including RA. Experimental studies and clinical trials have demonstrated the high power of MSCs in modulating the immune system. In this article, we first examine the mechanism of RA disease, the role of cytokines and existing medicinal therapies. We then discuss the immunomodulatory function of MSCs from different perspectives. Our understanding of how MSCs work in suppressing the immune system will lead to better utilization of these cells as a promising tool in the treatment of autoimmune diseases.

Perspective: Daniela Novick, cytokines and their receptors

This Perspective highlights the work of Dr. Daniela Novick in the field of cytokine biology. Using affinity chromatography to characterize cytokine-binding proteins, she identified soluble forms of the receptors as well as binding proteins for several cytokines, including tumor necrosis factor, interleukin (IL) 6, IL-18 and IL-32. Importantly, her work has been key in the development of monoclonal antibodies against interferons and cytokines. This Perspective discusses her contribution to the field and highlights her recent review on this topic.

TNF-α impairs EP4 signaling through the association of TRAF2-GRK2 in primary fibroblast-like synoviocytes

Our previous study showed that chronic treatment with tumor necrosis factor-α (TNF-α) decreased cAMP concentration in fibroblast-like synoviocytes (FLSs) of collagen-induced arthritis (CIA) rats. In this study we investigated how TNF-α impairs cAMP homeostasis, particularly clarifying the potential downstream molecules of TNF-α and prostaglandin receptor 4 (EP4) signaling that would interact with each other. Using a cAMP FRET biosensor PM-ICUE3, we demonstrated that TNF-α (20 ng/mL) blocked ONO-4819-triggered EP4 signaling, but not Butaprost-triggered EP2 signaling in normal rat FLSs. We showed that TNF-α (0.02-20 ng/mL) dose-dependently reduced EP4 membrane distribution in normal rat FLS. TNF-α significantly increased TNF receptor 2 (TNFR2) expression and stimulated proliferation in human FLS (hFLS) via ecruiting TNF receptor-associated factor 2 (TRAF2) to cell membrane. More interestingly, we revealed that TRAF2 interacted with G protein-coupled receptor kinase (GRK2) in the cytoplasm of primary hFLS and helped to bring GRK2 to cell membrane in response of TNF-α stimulation, the complex of TRAF2 and GRK2 then separated on the membrane, and translocated GRK2 induced the desensitization and internalization of EP4, leading to reduced production of intracellular cAMP. Silencing of TRAF2 by siRNA substantially diminished TRAF2-GRK2 interaction, blocked the translocation of GRK2, and resulted in upregulated expression of membrane EP4 and intracellular cAMP. In CIA rats, administration of paroxetine to inhibit GRK2 effectively improved the symptoms and clinic parameters with significantly reduced joint synovium inflammation and bone destruction. These results elucidate a novel form of cross-talk between TNFR (a cytokine receptor) and EP4 (a typical G protein-coupled receptor) signaling pathways. The interaction between TRAF2 and GRK2 may become a potential new drug target for the treatment of inflammatory diseases.

Engineering Strategies for Immunomodulatory Cytokine Therapies - Challenges and Clinical Progress

Cytokines are immunoregulatory proteins involved in many pathological states with promising potential as therapeutic agents. A diverse array of cytokines have been studied in preclinical disease models since the 1950s, some of which became successful biopharmaceutical products with the advancement of recombinant protein technology in the 1980s. However, following these early approvals, clinical translation of these natural immune signaling molecules has been limited due to their pleiotropic action in many cell types, and the fact that they have evolved to act primarily locally in tissues. These characteristics, combined with poor pharmacokinetics, have hindered the delivery of cytokines via systemic administration routes due to dose-limiting toxicities. However, given their clinical potential and recent clinical successes in cancer immunotherapy, cytokines continue to be extensively pursued in preclinical and clinical studies, and a range of molecular and formulation engineering strategies are being applied to reduce treatment toxicity while maintaining or enhancing therapeutic efficacy. This review provides a brief background on the characteristics of cytokines and their history as clinical therapeutics, followed by a deeper discussion on the engineering strategies developed for cytokine therapies with a focus on the translational relevance of these approaches.

IL-15 is a biomarker involved in the development of rapidly progressive interstitial lung disease complicated with polymyositis/dermatomyositis

BACKGROUND

Polymyositis/dermatomyositis (PM/DM) is an autoimmune disease that is sometimes complicated with rapidly progressive interstitial lung disease (RPILD). However, serum and lung biomarkers that can predict RPILD development remain unclear.

OBJECTIVES

To determine potential serum and lung biomarkers that can predict RPILD development in patients with PM/DM-ILD.

METHODS

In total, 49 patients with PM/DM-ILD were enrolled. We measured the serum levels of 41 cytokines/chemokines, ferritin and anti-MDA5 antibody, compared them between the RPILD (n = 23) and non-RPILD (n = 26) groups, and ranked them by their importance through random forest analysis. To distinguish the two groups, we determined biomarker combinations by logistic regression analysis. We also measured the bronchoalveolar lavage fluid (BALF) levels of 41 cytokines/chemokines. Using immunohistochemistry, we examined IL-15 expression in lung tissues. The IL-15 production was also investigated using A549 and BEAS-2B cells.

RESULTS

The RPILD group had significantly higher IL-15, IL-1RA, IL-6, CXCL10, VCAM-1, anti-MDA5 antibody and ferritin serum levels than the non-RPILD group, but it had a significantly low CCL22 level. Meanwhile, anti-MDA5 antibody, IL-15, CXCL8, CCL22, IL-1RA and ferritin were the best combination to distinguish the two groups. IL-15 and CCL22 were also predictive marker for RPILD development in anti-MDA5 antibody-positive patients. Additionally, the RPILD group had significantly high IL-15 levels in BALF. The lung tissues expressed IL-15, which increased after cytokine stimulation in the A549 cells.

CONCLUSION

This study identified a combination of biomarkers predicting PM/DM-RPILD progression, and IL-15 is an important cytokine for predicting RPILD development and reflecting ILD severity.

Macrophage Polarization in Chronic Lymphocytic Leukemia: Nurse-Like Cells Are the Caretakers of Leukemic Cells

Macrophages are terminally differentiated innate immune cells. Through their activation, they can be polarized towards the pro-inflammatory M1 type or the wound healing-associated, anti-inflammatory M2 type macrophages. In the tumor microenvironment (TME), M2 is the dominant phenotype and these cells are referred to as tumor-associated macrophages (TAMs). TAMs secrete cytokines and chemokines, exerting an antiapoptotic, proliferative and pro-metastatic effect on the tumor cells. TAMs can be found in many cancers, including chronic lymphocytic leukemia (CLL), where they are called nurse-like cells (NLCs). Despite the generally indolent behavior of CLL, the proportion of treatment-refractory patients is significant. As with the majority of cancers, despite significant recent progress, CLL pathogenesis is poorly understood. The emerging role of the TME in nurturing the neoplastic process warrants the investigation of macrophages as a significant pathogenetic element of tumors. In this paper, we review the current knowledge on the role of stromal macrophages in CLL.

Alarmins from conjunctival fibroblasts up-regulate matrix metalloproteinases in corneal fibroblasts

AIM

To explore the effects of alarmins produced by necrotic human conjunctival fibroblasts on the release of matrix metalloproteinases (MMPs) by human corneal fibroblasts (HCFs).

METHODS

A necrotic cell supernatant (NHCS) was prepared by subjecting human conjunctival fibroblasts to three cycles of freezing and thawing. The amounts of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in NHCS were determined by enzyme-linked immunosorbent assays. HCFs exposed to NHCS or other agents in culture were assayed for the release of MMPs as well as for intracellular signaling by immunoblot analysis. The abundance of MMP mRNAs in HCFs was examined by reverse transcription and real-time polymerase chain reaction analysis.

RESULTS

NHCS increased the release of MMP-1 and MMP-3 by HCFs as well as the amounts of the corresponding mRNAs in the cells. NHCS also induced activation of mitogen-activated protein kinase (MAPK) signaling pathways mediated by extracellular signal-regulated kinase (ERK), p38, and c-Jun NH₂-terminal kinase (JNK) as well as elicited that of the nuclear factor (NF)-κB signaling pathway by promoting phosphorylation of the endogenous NF-κB inhibitor IκB-α. Inhibitors of MAPK and NF-κB signaling as well as IL-1 and TNF-α receptor antagonists attenuated the NHCS-induced release of MMP-1 and MMP-3 by HCFs. Furthermore, IL-1β and TNF-α were both detected in NHCS, and treatment of HCFs with these cytokines induced the release of MMP-1 and MMP-3 in a concentration-dependent manner.

CONCLUSION

Alarmins, including IL-1β and TNF-α, produced by necrotic human conjunctival fibroblasts triggered MMP release in HCFs through activation of MAPK and NF-κB signaling. IL-1β and TNF-α are therefore potential therapeutic targets for the amelioration of corneal stromal degradation in severe ocular burns.

Interleukin-1 Family Cytokines: Keystones in Liver Inflammatory Diseases

The pyrogenic property being the first activity described, members of the interleukin-1 superfamily (IL-1α, IL-1β, IL-18, and the newest members: IL-33, IL-36, IL-37, and IL-38) are now known to be involved in several inflammatory diseases such as obesity, atherosclerosis, cancer, viral and parasite infections, and auto-inflammatory syndromes as well as liver diseases. Inflammation processes are keystones of chronic liver diseases, of which the etiology may be viral or toxic, as in alcoholic or non-alcoholic liver diseases. Inflammation is also at stake in acute liver failure involving massive necrosis, and in ischemia-reperfusion injury in the setting of liver transplantation. The role of the IL-1 superfamily of cytokines and receptors in liver diseases can be either protective or pro-inflammatory, depending on timing and the environment. Our review provides an overview of current understanding of the IL-1 family members in liver inflammation, highlighting recent key investigations, and therapeutic perspectives. We have tried to apply the concept of trained immunity to liver diseases, based on the role of the members of the IL-1 superfamily, first of all IL-1β but also IL-18 and IL-33, in modulating innate lymphoid immunity carried by natural killer cells, innate lymphoid cells or innate T-αβ lymphocytes.

Co-culture with synovial tissue in patients with rheumatoid arthritis suppress cell proliferation by regulating MAPK pathway in osteoblasts

There is growing evidence that synovial tissue affects osteoblasts although the mechanisms behind the aberrant bone metabolism in rheumatoid arthritis (RA) are unclear. The aim of this study is to preliminarily establish a co-culture system of rheumatoid arthritis-derived synovial tissue (RAS) and osteoblasts in vitro and to investigate the potential mechanism of RAS on osteoblasts. A consistent volume of approximately 85 mm³ of RAS was cultured isolated and co-cultured with Hfob1.19 cells for up to 21 days. Equal volume of normal synovial tissue (NS) was co-cultured as a control group. Cell proliferation, cell cycle and bone markers were valued and the mechanisms underlying MAPK pathway have been fully delineated. Our findings suggested that co-cultures with RAS exhibited decreased proliferation of Hfob1.19 cells. Moreover, gene and protein expressions of GLUT3 in cells were suppressed, and the cell cycle was also down-regulated. The expressions of related proteins of MAPKs (JNK and p38) signaling pathway were found to be inhibited. Rescue experiments demonstrated that co-cultures with RAS could decrease the growth and cell cycle of Hfob1.19 cells, which were reversed by p-JNK and p-p38 over expression. In conclusion, this study suggested that synovial tissue in patients with RA may negatively regulate osteoblasts proliferation by declining MAPK pathway.

Ruthenium pyridyl thiocyanate complex increased the production of pro-inflammatory TNFα and IL1β cytokines by the LPS stimulated mammalian macrophages in vitro

Every cell in our body depends on the electron transport processes in order to generate energy and function properly. Being able to regulate the metabolic activity of a cell would enable us altering its function and eventually lead us to a desired biological outcome at the cellular level and more desirably at a systemic level. Immunomodulatory or immunostimulatory molecules have been focus of the recent studies in order to regulate or boost the activities of the immune system cells and suppress or eliminate the disease conditions such as cancer, autoimmune reactions, inflammatory disorders as well as infections. In our study we used a ruthenium pyridyl thiocyanate complex, K330, to examine its effect on the activity of the innate immune system cells, macrophages in vitro. K330 was our candidate due to its application in the solar cells. Especially, due to its ability to get involved in electron transfer systems we hypothesized that it could change the activity of the immune system cells at cellular level, possibly by interfering the electron transfer reactions of the cells. Our results support our hypothesis since K330 lead to a significant increase in TNFα and IL1β cytokine production levels by LPS stimulated macrophages compared to only LPS treated control groups. Based on our in vitro results, K330 can also be utilized as an adjuvant candidate in vaccinations where the antigen itself is not sufficient to generate a proper immune response.

A fascinating story of the discovery & development of biologicals for use in clinical medicine

A young physician starting a fresh career in medicine in this millennium would hardly stop to think about the genesis of a particular biological drug that he/she will be prescribing for a patient evaluated in the morning outpatient department. For him/her, this is now routine, and the question of 'Who', 'How' and 'When' about these biologicals would be the last thing on their mind. However, for those who came to the medical profession in the 1950s, 1960s and 1970s, these targeted drugs are nothing short of 'miracles'. It would be a fascinating story for the young doctor to learn about the long journey that the dedicated biomedical scientists of yesteryears took to reach the final destination of producing such wonder drugs. The story is much like an interesting novel, full of twists and turns, heart-breaking failures and glorious successes. The biologicals acting as 'targeted therapy' have not only changed the natural history of a large number of incurable/uncontrollable diseases but have also transformed the whole approach towards drug development. From the classical empirical process, there is now a complete shift towards understanding the disease pathobiology focusing on the dysregulated molecule(s), targeting them with greater precision and aiming for better results. Seminal advances in understanding the disease mechanism, development of remarkably effective new technologies, greater knowledge of the human genome and genetic medicine have all made it possible to reach the stage where artificially developed 'targeted' drugs are now therapeutically used in routine clinical medicine.