IL-6/IL-12 Cytokine Receptor Shuffling of Extra- and Intracellular Domains Reveals Canonical STAT Activation via Synthetic IL-35 and IL-39 Signaling

Abnormalities of IL-12 Family Cytokine Pathways in Autosomal Dominant Polycystic Kidney Disease Progression

Background and Objectives: Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most frequent genetic renal disease with a complex physiopathology. More and more studies sustain that inflammation plays a crucial role in ADPKD pathogenesis and progression. We evaluated IL-12 involvement in ADPKD pathophysiology by assessing the serum levels of its monomers and heterodimers. Materials and Methods: A prospective case-control study was developed and included 66 ADPKD subjects and a control group of 40 healthy subjects. The diagnosis of ADPKD was based on familial history clinical and imagistic exams. The study included subjects with eGFR > 60 mL/min/1.73 mp, with no history of hematuria or other renal disorders, with stable blood pressure in the last 6 months. We tested serum levels of monomers IL-12 p40 and IL-12 p35 and heterodimers IL-12 p70, IL-23, IL 35, assessed by ELISA method. Results: IL-12 family programming was abnormal in ADPKD patients. IL-12p70, IL-12p40, and IL-23 secretion increased, while IL-12p35 and IL-35 secretion decreased compared to control. IL-12p70, IL-12p40, and IL-23 had a progressive increase correlated with immune response amplification, a decrease of eGFR, an increase in TKV, and in albuminuria. On the other hand, IL-35 and IL-12p35 were correlated negatively with CRP and albuminuria and positively with eGFR in advanced ADPKD. Conclusions: The present study investigated IL-12 cytokine family members' involvement in ADPKD pathogenesis, enriching our understanding of inflammation in the most common renal genetic disorder.

Exploring the landscape of synthetic IL-6-type cytokines

Interleukin-6 (IL-6)-type cytokines not only have key immunomodulatory functions that affect the pathogenesis of diseases such as autoimmune diseases, chronic inflammatory conditions, and cancer, but also fulfill important homeostatic tasks. Even though the pro-inflammatory arm has hindered the development of therapeutics based on natural-like IL-6-type cytokines to date, current synthetic trends might pave the way to overcome these limitations and eventually lead to immune-inert designer cytokines to aid type 2 diabetes and brain injuries. Those synthetic biology approaches include mutations, fusion proteins, and inter-cytokine swapping, and resulted in IL-6-type cytokines with altered receptor affinities, extended target cell profiles, and targeting of non-natural cytokine receptor complexes. Here, we survey synthetic cytokine developments within the IL-6-type cytokine family and discuss potential clinical applications.

Enhancing CAR T-cell Therapy Using Fab-Based Constitutively Heterodimeric Cytokine Receptors

Adoptive T-cell therapy aims to achieve lasting tumor clearance, requiring enhanced engraftment and survival of the immune cells. Cytokines are paramount modulators of T-cell survival and proliferation. Cytokine receptors signal via ligand-induced dimerization, and this principle has been hijacked utilizing nonnative dimerization domains. A major limitation of current technologies resides in the absence of a module that recapitulates the natural cytokine receptor heterodimeric pairing. To circumvent this, we created a new engineered cytokine receptor able to constitutively recreate receptor-heterodimer utilizing the heterodimerization domain derived from the IgG1 antibody (dFab_CCR). We found that the signal delivered by the dFab_CCR-IL2 proficiently mimicked the cytokine receptor heterodimerization, with transcriptomic signatures like those obtained by activation of the native IL2 receptor. Moreover, we found that this dimerization structure was agnostic, efficiently activating signaling through four cytokine receptor families. Using a combination of in vivo and in vitro screening approaches, we characterized a library of 18 dFab_CCRs coexpressed with a clinically relevant solid tumor-specific GD2-specific chimeric antigen receptor (CAR). Based on this characterization, we suggest that the coexpression of either the common β-chain GMCSF or the IL18 dFab_CCRs is optimal to improve CAR T-cell expansion, engraftment, and efficacy. Our results demonstrate how Fab dimerization is efficient and versatile in recapitulating a cytokine receptor heterodimerization signal. This module could be applied for the enhancement of adoptive T-cell therapies, as well as therapies based on other immune cell types. Furthermore, these results provide a choice of cytokine signal to incorporate with adoptive T-cell therapies.

The IL-12 family cytokines in fish: Molecular structure, expression profile and function

Interleukin (IL)-12 family cytokines including IL-12, IL-23, IL-27, IL-35 and IL-39 are heterodimeric cytokines composed of two subunits, an α-chain (entitled p35, p19 and p28) and a β-chain (namely p40 and Epstein-Barr virus-induced gene 3, EBI3). Unlike in mammals, specific whole genome duplication events in fish may generate more paralogues of these subunits as the components of IL-12 family cytokines. Although all subunit genes of IL-12 family have been isolated and identified in various fish species, some important issues on fish IL-12 family are needed to be addressed compared to the extensive study in mammals: Whether the expansion of these subunit genes results in the generation of multiple isoforms of the family cytokines; Whether the related receptor genes have similar complex repertoire corresponding to their ligands; How about the expression kinetics of these subunit paralogues particularly under the circumstance of pathogen infection and immune stimulation; How about the functional properties of IL-12 family in fish. In the past ten years, these concerns have received increasing attentions to establish the biological significance of this family cytokines in fish immunity. In this review, we summarized the current understanding of IL-12 family with a special focus on the molecular structures, inducible expression profiles and functions of IL-12 family members in fish.

INTERLEUKIN-35 DOWNREGULATES THE IMMUNE RESPONSE OF EFFECTOR CD4 + T CELLS VIA RESTRICTING HIGH MOBILITY GROUP BOX-1 PROTEIN-DEPENDENT AUTOPHAGY IN SEPSIS

ABSTRACT

Background: Immunosuppression is critically involved in the development of sepsis and is closely associated with poor outcomes. The novel role of the anti-inflammatory cytokine IL-35 in sepsis was examined. Methods: Sepsis was induced by in C57BL/6 mice cecal ligation and puncture (CLP). The impacts of IL-35 on effector CD4 + T cells were investigated by examining cell proliferation and the Th1/Th2 ratio in the presence of recombinant IL-35 (rIL-35) or anti-IL-35 (EBI3). The regulatory effect of IL-35 on autophagy was evaluated by measuring autophagy markers and autophagic flux in CLP mice in vivo and in activated effector CD4 + T cells in vitro . Results: IL-35 levels were significantly increased in the serum and spleens of septic mice. rIL-35 administration after CLP further decreased proliferation and the Th1/Th2 ratio in effector CD4 + T cells and significantly shortened the survival time. Sepsis-induced autophagy activation was protective in effector CD4 + T cells and was blocked by rIL-35. The inhibitory effect of IL-35 on autophagy was observed in activated effector CD4 + T cells in vitro , and this effect was mediated by restricting high mobility group box-1 protein (HMGB1) translocation. Conclusion: IL-35 is an immunosuppressive cytokine that impairs CD4 + T-cell proliferation and differentiation in sepsis, and the effect might be mediated by reducing HMGB1-dependent autophagy.

The roles and clinical applications of interleukins in endometrial carcinoma

As a common malignant tumor of the female reproductive system, endometrial carcinoma (EC) seriously endangers women's health with an increasing incidence. The oncogenesis and progression of cancer are closely linked with immune microenvironment, of which interleukins are the important components. In order to illustrate the roles and clinical applications of interleukins in EC, literature of interleukins and EC were reviewed. Based on the present studies, interleukins play crucial roles in the oncogenesis and development of EC via regulating the proliferation, migration, invasion, angiogenesis, apoptosis, pyroptosis and autophagy of EC as well as the immune function against EC. And some of the interleukins seems to have prospective clinical applications in EC, such as evaluating the risk of tumorigenesis, discriminating the malignancy from benign disorders or normal condition, indicating cancer aggressiveness, predicting the prognosis of patients and serving as the novel therapy. However, there is still a long way to go before the clinical applications of interleukins in EC come into reality. Nevertheless, it is certain that the exploration of interleukins will definitely be of great benefit to the screening, diagnosis and treatment of EC in the future.

STING-induced regulatory B cells compromise NK function in cancer immunity

An immunosuppressive tumour microenvironment is a major obstacle in the control of pancreatic and other solid cancers1-3. Agonists of the stimulator of interferon genes (STING) protein trigger inflammatory innate immune responses to potentially overcome tumour immunosuppression4. Although these agonists hold promise as potential cancer therapies5, tumour resistance to STING monotherapy has emerged in clinical trials and the mechanism(s) is unclear5-7. Here we show that the administration of five distinct STING agonists, including cGAMP, results in an expansion of human and mouse interleukin (IL)-35+ regulatory B cells in pancreatic cancer. Mechanistically, cGAMP drives expression of IL-35 by B cells in an IRF3-dependent but type I interferon-independent manner. In several preclinical cancer models, the loss of STING signalling in B cells increases tumour control. Furthermore, anti-IL-35 blockade or genetic ablation of IL-35 in B cells also reduces tumour growth. Unexpectedly, the STING-IL-35 axis in B cells reduces proliferation of natural killer (NK) cells and attenuates the NK-driven anti-tumour response. These findings reveal an intrinsic barrier to systemic STING agonist monotherapy and provide a combinatorial strategy to overcome immunosuppression in tumours.

Biogenesis and engineering of interleukin 12 family cytokines

Interleukin 12 (IL-12) family cytokines are secreted proteins that regulate immune responses. Each family member is a heterodimer and nature uses shared building blocks to assemble the functionally distinct IL-12 cytokines. In recent years we have gained insights into the molecular principles and cellular regulation of IL-12 family biogenesis. For each of the family members, generally one subunit depends on its partner to acquire its native structure and be secreted from immune cells. If unpaired, molecular chaperones retain these subunits in cells. This allows cells to regulate and control secretion of the highly potent IL-12 family cytokines. Molecular insights gained into IL-12 family biogenesis, structure, and function now allow us to engineer IL-12 family cytokines to develop novel immunotherapeutic approaches.

The diagnostic value of cytokines for the discrimination of vertebral osteomyelitis and degenerative diseases of the spine

Vertebral osteomyelitis (VO) is a primary infection of the endplates of the vertebral bodies with secondary infection of the adjacent intervertebral discs. Diagnosis is often delayed due to unspecific symptoms and a lack of specific infection markers. In this prospective study, we determined the suitability of 27 cytokines for the discrimination of VO and degenerative diseases of the spine and compared its diagnostic potential in relation to the C-reactive protein (CRP), which is widely used as a non-specific inflammation marker in clinical diagnostics. The patients included in this study underwent surgical stabilization of the lumbar and/or thoracic spine with removal of 1 or more affected intervertebral discs, as therapy for VO (n = 16) or for erosive osteochondrosis (EO, control group, n = 20). We evaluated the cytokine and CRP concentrations before (pre-OP = -20-0d where 0 means the day of surgery) and after surgery (post-OP) on days 3-5, 6-11, 40-56, and 63-142. Compared to the control patients pre-OP, a significantly higher elevation of the 4 cytokines IL-6, IL-8, IL-12 (p70), and VEGF as well as CRP were found in the VO patients, showing an area under the curve > 0.80 pre-OP. No significant differences were observed between VO patients with high and low virulent bacteria with respect to all 5 elevated biomarkers. This is the first prospective study in which a broad spectrum of 27 cytokines was analysed via multiplex assay using sera from patients with and without VO. Our results show that, in addition to CRP, 4 different cytokines were significantly altered in VO but not control patients. The results implicate that these candidate cytokines may be used in a multiplex assay for discrimination between VO and degenerative diseases of the spine.

Interleukin-35 inhibits lipopolysaccharide-induced endothelial cell activation by downregulating inflammation and apoptosis

Inflammation is an essential factor contributing to sepsis-induced endothelial cell (EC) activation. Interleukin-35 (IL-35) is an anti-inflammatory/immunosuppressive cytokine that exerts protective effects on many inflammatory diseases. In this study, we investigated the effects of IL-35 on lipopolysaccharide (LPS)-induced EC activation and the potential underlying mechanism. Human umbilical vein endothelial cells (HUVECs) were incubated with LPS (1 μg/ml) for 24 h and then cocultured with different concentrations (0, 1, 10, or 100 ng/ml) of recombinant human IL-35 (rhIL-35) for 12 h. Flow cytometry analysis revealed that IL-35 inhibited LPS-induced HUVEC apoptosis in a dose-dependent manner. RT-qPCR and Western blot analyses showed significantly higher mRNA and protein levels of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and the inflammatory factors IL-6 and IL-8 in the LPS group than in the control group. These changes were alleviated by IL-35 treatment, suggesting that IL-35 protects ECs by downregulating inflammation. Furthermore, IL-35 induced signal transducer and activator of transcription 1 (STAT1) and STAT4 activation and promoted their interaction. Blocking STAT1 or STAT4 expression by fludarabine (STAT1 inhibitor) treatment or siRNA-STAT4-interfering fragment transfection inhibited the protective effect of IL-35 on ECs. Moreover, we observed a similar protective effect of IL-35 treatment on ECs in a mouse sepsis model induced by intraperitoneal LPS injection. This study indicated that IL-35 exerts anti-inflammatory and antiapoptotic effects on LPS-induced EC activation by activating the STAT1 and STAT4 signaling pathways.

A Chaperone-Like Role for EBI3 in Collaboration With Calnexin Under Inflammatory Conditions

The interleukin-6 (IL-6)/IL-12 family of cytokines plays critical roles in the induction and regulation of innate and adaptive immune responses. Among the various cytokines, only this family has the unique characteristic of being composed of two distinct subunits, α- and β-subunits, which form a heterodimer with subunits that occur in other cytokines as well. Recently, we found a novel intracellular role for one of the α-subunits, Epstein-Barr virus-induced gene 3 (EBI3), in promoting the proper folding of target proteins and augmenting its expression at the protein level by binding to its target protein and a well-characterized lectin chaperone, calnexin, presumably through enhancing chaperone activity. Because calnexin is ubiquitously and constitutively expressed but EBI3 expression is inducible, these results could open an avenue to establish a new paradigm in which EBI3 plays an important role in further increasing the expression of target molecules at the protein level in collaboration with calnexin under inflammatory conditions. This theory well accounts for the heterodimer formation of EBI3 with p28, and probably with p35 and p19 to produce IL-27, IL-35, and IL-39, respectively. In line with this concept, another β-subunit, p40, plays a critical role in the assembly-induced proper folding of p35 and p19 to produce IL-12 and IL-23, respectively. Thus, chaperone-like activities in proper folding and maturation, which allow the secretion of biologically active heterodimeric cytokines, have recently been highlighted. This review summarizes the current understanding of chaperone-like activities of EBI3 to form heterodimers and other associations together with their possible biological implications.

CD25+ B cells produced IL-35 and alleviated local inflammation during experimental periodontitis

BACKGROUND AND OBJECTIVE

Host immunity is crucial during periodontal inflammations. B cells are considered to have a function of immunoregulation, and TLRs are considered to be crucial in this process. The present study illustrates the potential roles and rules of CD25+ B cells during periodontitis, especially its effect on regulating host IL-35 level and Th1, Th17, and Treg differentiation.

MATERIAL AND METHODS

The proportion of local and systemic CD25+ B cell subpopulations from periodontitis models were identified by flow cytometry. To illustrate further mechanism, B cells were cultured with a different type of TLR activators. Expression of IL-10, IL-35, and TGF-β was detected by ELISA and real-time PCR. We also set adoptive transfer models by using CD25+ B cells. Alveolar bone erosion, proportion of Th1, Th17, and Tregs, and levels of IFN-γ, TNF-α, IL-1β, and IL-17 were identified.

RESULT

Periodontitis induces more CD25+ B cell subpopulations and promotes their IL-10, IL-35, and TGF-βproduction. TLR activators enhanced Breg proliferation and function. LPS+CpG obviously induced more CD25+ B cell differentiation and production of IL-10, IL-35, and TGF-β. Adoptive transfer of CD25+ B cells reduces alveolar bone destruction and local Tregs, proportion, especially the local level of IFN-γ and IL-17. In addition, adoptive transfer of CD25+ B cells remedies the pathological change in the proportion of IL-1β and Th1/Th17 in local lesions. We did not find any significant difference in peripheral blood, regardless of group and detected items.

CONCLUSION

Results of the present study clarify that CD25+ B cells enlarged and produced more IL-10, IL-35 and TGF-β during periodontitis, activation of TLR4 and TLR9 played crucial roles in this process. Also, CD25+ B cells alleviated periodontal inflammation and alveolar bone resorption. Our findings further expanded the potential of B cells during periodontitis.

Pro- and anti-apoptotic fate decisions induced by di- and trimeric synthetic cytokine receptors

Synthetic strategies to activate cytokine receptors so far only address standard dimeric cytokine receptor assemblies. The 19 ligands of the tumor necrosis factor superfamily (TNFSF), however, form noncovalent trimers and receptor trimerization is considered to be essential for receptor activation. Synthetic TNFR1, TNFR2, and Fas/CD95 receptors were activated by synthetic trimeric ligands which induced NF-κB signaling or Caspase-induced apoptosis. Albeit dimeric receptor activation did not induce synthetic TNFR1 and TNFR2 signaling, dimeric FasL induced extenuated apoptosis. Simultaneous integration of dimeric Interleukin (IL-)6 receptor gp130 and trimeric Fas as synthetic cytokine receptors in one cell enabled binary cell fate decisions, gp130-mediated proliferation or Fas-mediated apoptosis. In summary, our modular fully synthetic cytokine signaling system allows precisely orchestrated cellular responses to selectively induce pro- and anti-apoptotic signaling via canonical dimeric receptors of the IL-6 family and non-canonical trimeric receptor complexes of the TNF superfamily.

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SyCyRs induce TNFR1 or TNFR2 mediated NF-κB activation as trimers or oligomers.

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Fas-SyCyR induces Caspase-induced apoptosis as trimer and as dimer.

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Synthetic loss of function Fas-SyCyR fails to induce Caspase mediated apoptosis.

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gp130-and Fas-SyCyR in one cell enable proliferation via gp130 or apoptosis via Fas.

The immunological impact of adenovirus early genes on vaccine-induced responses in mice and nonhuman primates

Adenovirus (Ad) is being explored for use in the prevention and treatment of a variety of infectious diseases and cancers. Ad with a deletion in early region 3 (ΔE3) provokes a stronger immune response than Ad with deletions in early regions 1 and E3 (ΔE1/ΔE3). The ΔE1/ΔE3 Ads are more popular because they can carry a larger transgene and because of the deleted E1 (E1A and E1B), are perceived safer for clinical use. Ad with a deletion in E1B55K (ΔE1B55K) has been in phase III clinical trials for use in cancer therapy in the US and has been approved for use in head and neck tumor therapy in China, demonstrating that Ad containing E1A are safe for clinical use. We have shown previously that ΔE1B55K Ad, even while promoting lower levels of an inserted transgene, promoted similar levels of transgene-specific immune responses as a ΔE3 Ad. Products of the Ad early region 4 (E4) limit the ability of cells to mount an innate immune response. Using this knowledge, we deleted the Ad E4 open reading frames 1-4 (E4orf1-4) from the ΔE1B55K Ad. Here, we show that innate cytokine network genes are elevated in the ΔE4 Ad-infected cells beyond that of ΔE3 Ad-infected cells. Further, in immunized mice the IgG2a subclass was favored as was the IgG1 subclass in immunized nonhuman primates. Thus, Ad E4 impacts immune responses in cells, in immunized mice, and immunized nonhuman primates. These Ad may offer advantages that are beneficial for clinical use.Importance: Adenovirus (Ad) is being explored for use in the prevention and treatment of a variety of infectious diseases and cancers. Here we provide evidence in cells, mice, and nonhuman primates supporting the notion that Ad early gene-products limit specific immune responses. Ad constructed with deletions in early genes and expressing HIV envelope protein was shown to induce greater HIV-specific cellular immune responses and higher titer antibodies compared to the parental Ad with the early genes. In addition to eliciting enhanced immunity, the deleted Ad possesses more space for insertion of additional or larger transgenes needed for targeting other infectious agents or cancers.

Interleukin-39 exacerbates concanavalin A-induced liver injury

BACKGROUND

Interleukin (IL)-39 is a novel member of IL-12 family and has been reported to play a pro-inflammatory role in lupus-like mice, but its function in concanavalin A (ConA)-induced liver injury is currently unclear.

MATERIALS AND METHODS

In this study, we investigated the effects of IL-39 expression in a mouse model of ConA induced-hepatitis. We first showed that delivery of plasmid DNA encoding mouse IL-39 using the hydrodynamic tail vein injection method increased IL-39 mRNA and protein levels in the liver. We then administrated mice with IL-39 plasmid before ConA injection and measured serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, inflammatory infiltration, and hepatocyte necrosis in the liver. Additionally, we further explored the potential mechanism of IL-39 in ConA-induced liver injury by measuring several inflammatory mediators.

RESULTS

We found that ectopic IL-39 expression promoted the ConA-induced increase in serum ALT and AST levels, inflammatory infiltration, and hepatocyte necrosis in the liver. We also observed that IL-39 plasmid administration significantly increased serum and liver interferon-γ, tumor necrosis factor-α, and IL-17A levels, but did not affect serum and liver IL-10 levels in ConA-induced hepatitis.

CONCLUSION

Our results suggest that IL-39 can exacerbate ConA-induced hepatitis and may be a therapeutic target in inflammatory liver disease.

IL-12 Family Cytokines in Cancer and Immunotherapy

The IL-12 family cytokines are a group of unique heterodimeric cytokines that include IL-12, IL-23, IL-27, IL-35 and, most recently, IL-39. Recent studies have solidified the importance of IL-12 cytokines in shaping innate and adaptive immune responses in cancer and identified multipronged roles for distinct IL-12 family members, ranging from effector to regulatory immune functions. These cytokines could serve as promising candidates for the development of immunomodulatory therapeutic approaches. Overall, IL-12 can be considered an effector cytokine and has been found to engage anti-tumor immunity by activating the effector Th1 response, which is required for the activation of cytotoxic T and NK cells and tumor clearance. IL-23 and IL-27 play dual roles in tumor immunity, as they can both activate effector immune responses and promote tumor growth by favoring immune suppression. IL-35 is a potent regulatory cytokine and plays a largely pro-tumorigenic role by inhibiting effector T cells. In this review, we summarize the recent findings on IL-12 family cytokines in the control of tumor growth with an emphasis primarily on immune regulation. We underscore the clinical implications for the use of these cytokines either in the setting of monotherapy or in combination with other conventional therapies for the more effective treatment of malignancies.

Lack of evidence for expression and function of IL-39 in human immune cells

Members of the IL-6/IL-12 cytokine family are critical regulators of innate and adaptive immunity and have emerged as key players controlling inflammatory and autoimmune disorders. This cytokine family comprises of IL-12, IL-23, IL-27, and IL-35, each consisting of distinct α- and β-cytokine subunits that form heterodimers. A new member of this family, IL-39, was identified in the murine species and was shown to consist of the IL-23p19 and Epstein-Barr Virus-induced 3 (EBI3) subunits. Subsequently, it was shown that IL-39 was implicated in the immunopathogenesis of murine experimental lupus erythematosus. The existence of IL-39 in the human system has yet to be confirmed. Based on the clinical success of IL-23p19 neutralizing approaches in moderate-to-severe psoriasis, anti-IL-23p19 antibodies in the clinic may not only neutralize IL-23, but additionally IL-39, implying that IL-39 might also contribute to the pathogenesis of psoriasis. It is therefore pivotal to demonstrate IL-39 expression and to characterize its function in the human system. In this study, we provided evidence for the existence of secreted heterodimeric p19 and EBI3 complexes in supernatants originating from p19 and EBI3 transfected HEK293FT cells. We attempted to detect IL-39 expression from stimulated human primary B cells, human keratinocytes and in vitro polarized human macrophages. Whereas, the expression of p19 and EBI3 mRNA was elevated, we failed to detect p19 and EBI3 heterodimers. Functional assays were conducted with conditioned media containing human IL-39 or with a human recombinant IL-39 Fc protein. Immune cells targeted by IL-39 in mouse, such as neutrophils and PBMCs, did not respond to human IL-39 stimulation and IL-39 failed to activate STAT3 in a reporter cell line. These results suggest that, while the secretion of p19/EBI3 complexes can be forced in human cells, it is secreted below the lower quantity of detection or it has no functional role.

[The expression and significance of interleukin-35 receptor in oral lichen planus]

OBJECTIVE

To investigate the expression of glycoprotein 130 (gp130) and interleukin 12 receptor β2 (IL-12Rβ2) in two subunits of interleukin-35 receptor (IL-35R), singal transducer and activator of transcription (STAT) 1 and STAT4 in oral lichen planus (OLP) tissues, and to explore the role and significance of IL-35R in the formation and development of OLP lesions.

METHODS

Totally 41 samples of OLP tissues (OLP group) and 15 samples of normal oral mucosa (control group) were collected. The expression levels of gp130, IL-12Rβ2, STAT1, STAT4 mRNA in the tissues were detected by real-time fluorescent quantitative polymerase chain reaction and the distribution and expression of protein gp130 and IL-12Rβ2 were detected by immunohistochemistry. The potential relationship between gp130 and IL-12Rβ2 and clinical features of OLP was analyzed.

RESULTS

1) The expression levels of gp130, IL-12Rβ2, STAT1 and STAT4 mRNA in the OLP group were significantly higher than those in the control group (P<0.05). 2) The positive expression rates of gp130 and IL-12Rβ2 protein in the OLP group were higher than those in the control group (P<0.05). The expression of gp130 and IL-12Rβ2 proteins in OLP tissues were positively correlated (r=0.984, P<0.001). 3) The expression rates of gp130 and IL-12Rβ2 protein in erosive OLP tissues were significantly higher than those in non-erosive ones (P<0.05).

CONCLUSIONS

The expression of IL-35R and STAT is up-regulated in OLP tissues, and the expression of IL-35R is related to the clinical classification of OLP, suggesting that IL-35R might play an important role in the formation and development of damage OLP lesions.

IL-12 and IL-23-Close Relatives with Structural Homologies but Distinct Immunological Functions

Cytokines of the IL-12 family show structural similarities but have distinct functions in the immune system. Prominent members of this cytokine family are the pro-inflammatory cytokines IL-12 and IL-23. These two cytokines share cytokine subunits and receptor chains but have different functions in autoimmune diseases, cancer and infections. Accordingly, structural knowledge about receptor complex formation is essential for the development of new therapeutic strategies preventing and/or inhibiting cytokine:receptor interaction. In addition, intracellular signaling cascades can be targeted to inhibit cytokine-mediated effects. Single nucleotide polymorphisms can lead to alteration in the amino acid sequence and thereby influencing protein functions or protein–protein interactions. To understand the biology of IL-12 and IL-23 and to establish efficient targeting strategies structural knowledge about cytokines and respective receptors is crucial. A highly efficient therapy might be a combination of different drugs targeting extracellular cytokine:receptor assembly and intracellular signaling pathways.

Synthetic interleukin 22 (IL-22) signaling reveals biological activity of homodimeric IL-10 receptor 2 and functional cross-talk with the IL-6 receptor gp130

Cytokine signaling is transmitted by cell-surface receptors that function as biological switches controlling mainly immune-related processes. Recently, we have designed synthetic cytokine receptors (SyCyRs) consisting of GFP and mCherry nanobodies fused to transmembrane and intracellular domains of cytokine receptors that phenocopy cytokine signaling induced by nonphysiological homo- and heterodimeric GFP-mCherry ligands. Interleukin 22 (IL-22) signals via both IL-22 receptor α1 (IL-22Rα1) and the common IL-10R2, belongs to the IL-10 cytokine family, and is critically involved in tissue regeneration. Here, IL-22 SyCyRs phenocopied native IL-22 signal transduction, indicated by induction of cytokine-dependent cellular proliferation, signal transduction, and transcriptome analysis. Whereas homodimeric IL-22Rα1 SyCyRs failed to activate signaling, homodimerization of the second IL-22 signaling chain, SyCyR(IL-10R2), which previously was considered not to induce signal transduction, led to induction of signal transduction. Interestingly, the SyCyR(IL-10R2) and SyCyR(IL-22Rα1) constructs could form functional heterodimeric receptor signaling complexes with the synthetic IL-6 receptor chain SyCyR(gp130). In summary, we have demonstrated that IL-22 signaling can be phenocopied by synthetic cytokine receptors, identified a functional IL-10R2 homodimeric receptor complex, and uncovered broad receptor cross-talk of IL-22Rα1 and IL-20R2 with gp130.

Interleukin 39: a new member of interleukin 12 family

Interleukin (IL)-12 family member is a heterodimer glycoprotein, composed of two covalently linked subunits, α and β chains. The α subunit consists of IL-23p19, IL-27p28, and IL-12p35, and the β subunit includes IL-12p40 and Epstein-Barr virus-induced gene (Ebi3). IL-39 is a new heterodimeric IL-12 family member composed of IL-23p19 and Ebi3 subunits. IL-39 is secreted by lipopolysaccharide-stimulated B cells. Other immune cells, such as dendritic cells and macrophages, express IL-39 mRNA. In lupus-like mice, GL7⁺B cells and CD138⁺plasma cells are highly activated and widely expressed, promoting high expression of IL-39. IL-39 mediates inflammatory responses through binding to a heterodimer of IL-23R/gp130 receptor and activation of signal transducer and activator of transcription (STAT)1/STAT3 signal molecules. The serum levels of IL-39 were significantly increased in patients with acute coronary syndrome compared with patients with normal coronary arteries. This review discusses the biological characteristics, receptor, and signal pathway as well as biological activity of IL-39 and its potential role in inflammation and other diseases.

Multimerization strategies for efficient production and purification of highly active synthetic cytokine receptor ligands

Cytokine signaling is transmitted by cell surface receptors which act as natural biological switches to control cellular functions such as immune reactions. Recently, we have designed synthetic cytokine receptors (SyCyRs) consisting of green fluorescent protein (GFP)- and mCherry-nanobodies fused to the transmembrane and intracellular domains of cytokine receptors. Following stimulation with homo- and heterodimeric GFP-mCherry fusion proteins, the resulting receptors phenocopied signaling induced by physiologically occurring cytokines. GFP and mCherry fusion proteins were produced in E. coli or CHO-K1 cells, but the overall yield and stability was low. Therefore, we applied two alternative multimerization strategies and achieved immunoglobulin Fc-mediated dimeric and coiled-coil GCN4pII-mediated trimeric assemblies. GFP- and/or mCherry-Fc homodimers activated synthetic gp130 cytokine receptors, which naturally respond to Interleukin 6 family cytokines. Activation of these synthetic gp130 receptors resulted in STAT3 and ERK phosphorylation and subsequent proliferation of Ba/F3-gp130 cells. Half-maximal effective concentrations (EC50) of 8.1 ng/ml and 0.64 ng/ml were determined for dimeric GFP-Fc and mCherry-Fc, respectively. This is well within the expected EC50 range of the native cytokines. Moreover, we generated tetrameric and hexameric GFP-mCherry-Fc fusion proteins, which were also biologically active. This highlighted the importance of close juxtaposition of two cytokine receptors for efficient receptor activation. Finally, we used a trimeric GCN4pII motif to generate homo-trimeric GFP and mCherry complexes. These synthetic cytokines showed improved EC50 values (GFP3: 0.58 ng/ml; mCherrry3: 0.37 ng/ml), over dimeric Fc fused variants. In conclusion, we successfully generated highly effective and stable multimeric synthetic cytokine receptor ligands for activation of synthetic cytokine receptors.

Interleukin 30 to Interleukin 40

Cytokines are important molecules that regulate the ontogeny and function of the immune system. They are small secreted proteins usually produced upon activation of cells of the immune system, including lymphocytes and myeloid cells. Many cytokines have been described, and several have been recognized as pivotal players in immune responses and in human disease. In fact, several anticytokine antibodies have proven effective therapeutics, especially in various autoimmune diseases. In the last 15 years, new cytokines have been described, and many remain poorly understood. Among the most recent cytokines discovered are interleukins-30 (IL-30) to IL-40. Several of these are members of other cytokine superfamilies, including several IL-1 superfamily members (IL-33, IL-36, IL-37, and IL-38) as well as several new members of the IL-12 family (IL-30, IL-35, and IL-39). The rest (IL-31, IL-32, IL-34, and IL-40) are encoded by genes that do not belong to any cytokine superfamily. Our aim of this review was to present a concise version of the information available on these novel cytokines to facilitate their understanding by members of the immunological community.

Immunoregulatory Functions of the IL-12 Family of Cytokines in Antiviral Systems

Members of the interleukin 12 (IL-12) family have been known to be inflammatory factors since their discovery. The IL-12 family consists of IL-12, IL-23, IL-27, IL-35, and a new member, IL-39, which has recently been identified and has not yet been studied extensively. Current literature has described the mechanisms of immunity of these cytokines and potential uses for therapy and medical cures. IL-12 was found first and is effective in combatting a wide range of naturally occurring viral infections through the upregulation of various cytokines to clear the infected cells. IL-23 has an essential function in immune networks, can induce IL-17 production, and can antagonize inhibition from IL-12 in the presence of T helper (Th) 17 cells, resulting in type II IFN (IFN-γ) regulation. IL-27 has a competitive relationship to IL-35 because they both include the same subunit, the Epstein–Barr virus-induced gene3 (EBi3). This review provides a simple introduction to the IL-12 family and focuses on their functions relevant to their actions to counteract viral infections.

Naturally occurring and synthetic constitutive-active cytokine receptors in disease and therapy

Cytokines control immune related events and are critically involved in a plethora of patho-physiological processes including autoimmunity and cancer development. Mutations which cause ligand-independent, constitutive activation of cytokine receptors are quite frequently found in diseases. Many constitutive-active cytokine receptor variants have been directly connected to disease development and mechanistically analyzed. Nature's solutions to generate constitutive cytokine receptors has been recently adopted by synthetic cytokine receptor biology, with the goal to optimize immune therapeutics. Here, CAR T cell immmunotherapy represents the first example to combine synthetic biology with genetic engineering during therapy. Hence, constitutive-active cytokine receptors are therapeutic targets, but also emerging tools to improve or modulate immunotherapeutic strategies. This review gives a comprehensive insight into the field of naturally occurring and synthetic constitutive-active cytokine receptors.

Interleukin-35 in immune-related diseases: protection or destruction

Interleukin-35 (IL-35) is a recently identified heterodimeric cytokine in the IL-12 family. It consists of an IL-12 subunit α chain (P35) and IL-27 subunit Epstein-Barr virus-induced gene 3 (EBI3) β chain. Unlike the other IL-12 family members, it signals through four unconventional receptors: IL-12Rβ2-IL-27Rα, IL-12Rβ2-IL-12Rβ2, IL-12Rβ2-GP130, and GP130-GP130. Interleukin-35 signaling is mainly carried out through the signal transducer and activator of transcription family of proteins. It is secreted not only by regulatory T (Treg) cells, but also by CD8+ Treg cells, activated dendritic cells and regulatory B cells. It exhibits immunosuppressive functions distinct from those of other members of the IL-12 family; these are mediated primarily by the inhibition of T helper type 17 cell differentiation and promotion of Treg cell proliferation. Interleukin-35 plays a critical role in several immune-associated diseases, such as autoimmune diseases and viral and bacterial infections, as well as in tumors. In this review, we summarize the structure and function of IL-35, describe its role in immune-related disorders, and discuss the mechanisms by which it regulates the development and progression of diseases, including inflammatory bowel disease, collagen-induced arthritis, allergic airway disease, hepatitis, and tumors. The recent research on IL-35, combined with improved techniques of studying receptors and signal transduction pathways, allows for consideration of IL-35 as a novel immunotherapy target.

The IL-23p19/EBI3 heterodimeric cytokine termed IL-39 remains a theoretical cytokine in man

Objective

The heterodimeric IL-12 family member cytokines including, IL-12, IL-23, IL-27, and IL-35 and have multiple roles in regulating innate and adaptive immunity with crucial functions in inflammatory disorders such as psoriasis. Chain pairing promiscuity is a feature of the IL-12 family. Recently, based on murine data, a new family member, IL-39, was proposed, consisting of IL23p19 (shared with IL-23) and EBI3 (shared with IL-27 and IL-35). IL-39 has subsequently been implicated in experimental murine lupus. Given the success of IL-23p19 therapeutic targeting in diseases including psoriasis, it is of great interest to confirm the presence of IL-39 in man. Human IL-39 is yet to be either detected or expressed, which has halted research in this area.

Methods

Using a disulphide-linked human chimera protein composing of IL-23p19 and EBI3 human chains, we stimulated human leukocytes, and analysed cytokine secretion and STAT3 phosphorylation.

Results and Conclusion

We report that this cytokine shows no activity in human cells. IL-39 chimera protein failed to induce either IL-6, IL-8, TNF, or IL-17A from leukocytes or STAT3 phosphorylation and thus, remains a ‘theoretical cytokine' in humans.

Emerging technologies in protein interface engineering for biomedical applications

Protein interactions communicate critical information from the environment into cells to orchestrate functional responses relevant to health and disease. Whereas the natural repertoire of protein interfaces is finite, biomolecular engineering tools provide access to an unlimited scope of potential interactions that can be custom-designed for affinity, specificity, mechanism, or other properties of interest. This review highlights recent developments in protein interface engineering that offer insight into human physiology to inform the design of new pharmaceuticals, with a particular focus on immunotherapeutics. We cover three innovative and translationally promising approaches: (1) reprogramming receptor oligomerization to manipulate signaling pathways; (2) computational protein interface design strategies; and (3) engineering bioorthogonal protein interaction networks.