Interleukin-22 in human inflammatory diseases and viral infections

The role of immune regulatory molecules in multiple sclerosis

Multiple sclerosis (MS) is the most common demyelinating disease which mainly impacts the integrity of central nervous system (CNS). MS etiology is not clearly known but genetic, environmental factors and immune system are the most frequently explored risk factors. Adaptive immune responses have a critical role in MS pathogenesis in which auto-reactive T-cells and autoantibodies are main orchestrators. Immune responses are modulated by inhibitory molecules which regulates adaptive system activation and hemostasis interface. These molecules suppress immune responses through inhibition of cytokine secretion and T cell proliferation and subsequently reducing the inflammation and respective damage. Therefore the critical role of inhibitory molecules in regulating the healthy and safe immune responses make them very attractive target for immunotherapy. In this review paper, the role of inhibitory molecules expressed on the various immune cell types in MS pathogenesis and experimental autoimmune encephalomyelitis (EAE) animal model will be summarized.

CD28 Autonomous Signaling Up-Regulates C-Myc Expression and Promotes Glycolysis Enabling Inflammatory T Cell Responses in Multiple Sclerosis

The immunopathogenesis of multiple sclerosis (MS) depend on the expansion of specific inflammatory T cell subsets, which are key effectors of tissue damage and demyelination. Emerging studies evidence that a reprogramming of T cell metabolism may occur in MS, thus the identification of stimulatory molecules and associated signaling pathways coordinating the metabolic processes that amplify T cell inflammation in MS is pivotal. Here, we characterized the involvement of the cluster of differentiation (CD)28 and associated signaling mediators in the modulation of the metabolic programs regulating pro-inflammatory T cell functions in relapsing-remitting MS (RRMS) patients. We show that CD28 up-regulates glycolysis independent of the T cell receptor (TCR) engagement by promoting the increase of c-myc and the glucose transporter, Glut1, in RRMS CD4⁺ T cells. The increase of glycolysis induced by CD28 was important for the expression of inflammatory cytokines related to T helper (Th)17 cells, as demonstrated by the strong inhibition exerted by impairing the glycolytic pathway. Finally, we identified the class 1A phosphatidylinositol 3-kinase (PI3K) as the critical signaling mediator of CD28 that regulates cell metabolism and amplify specific inflammatory T cell phenotypes in MS.

Serum cytokine measurements and biological therapy of psoriasis - Prospects for personalized treatment?

Psoriasis is an immune-mediated disease where the IL-23/Th17 axis as well as TNF comprise main targets of biological therapy. Immune profiling has so far not been embraced as a clinical tool. We aimed to investigate relationships between individual serum cytokine levels in 40 psoriasis patients before and after receiving biological therapy and Psoriasis Area and Severity Index (PASI) and Dermatological Life Quality Index (DLQI). Serum concentration of 25 cytokines was determined by Luminex technology. Mean PASI and DLQI decreased by 71% and 65%, respectively. Increase of IL-2 positively correlated with improvement of PASI and DLQI. Moreover, increase of IL-5, IL-10, IL-12, IL-22 and GM-CSF correlated with treatment effect. Notably, logistic regression revealed four times higher risk of having severe psoriasis when IL-17A increased by 1 pg/mL (OR: 4.06, P < 0.05). Selected serum cytokines might constitute useful biomarkers for monitoring disease activity and optimizing therapeutic strategies in psoriasis patients.

IL-20 receptor cytokines in autoimmune diseases

IL-19, IL-20, and IL-24 are the members of IL-10 family. They are also known as IL-20 receptor (IL-20R) cytokines as they all signal through the IL-20RA/IL-20RB receptor complex; IL-20 and IL-24 (but not IL-19) also signal through the IL-20RB/IL22RA1 receptor complex. Despite their protein structure homology and shared use of receptor complexes, they display distinct biological functions in immune regulation, tissue homeostasis, host defense, and oncogenesis. IL-20R cytokines can be expressed by both immune cells and epithelial cells, and are important for their interaction. In general, these cytokines are considered to be associated with pathogenesis of chronic inflammation and autoimmune diseases, including psoriasis, rheumatoid arthritis, and inflammatory bowel disease. However, a number of studies also highlighted their suppressive functions in regulating both innate and adaptive T cell responses and other immune cells, suggesting that the role of IL-20R cytokines in autoimmunity may be complex. In this review, we will discuss the immunobiological functions of IL-20R cytokines and how they are involved in regulating autoimmune diseases.

Phase IIa trial in Duchenne muscular dystrophy shows vamorolone is a first-in-class dissociative steroidal anti-inflammatory drug

We report a first-in-patient study of vamorolone, a first-in-class dissociative steroidal anti-inflammatory drug, in Duchenne muscular dystrophy. This 2-week, open-label Phase IIa multiple ascending dose study (0.25, 0.75, 2.0, and 6.0 mg/kg/day) enrolled 48 boys with Duchenne muscular dystrophy (4 to <7 years), with outcomes including clinical safety, pharmacokinetics and pharmacodynamic biomarkers. The study design included pharmacodynamic biomarkers in three contexts of use: 1. Secondary outcomes for pharmacodynamic safety (insulin resistance, adrenal suppression, bone turnover); 2. Exploratory outcomes for drug mechanism of action; 3. Exploratory outcomes for expanded pharmacodynamic safety. Vamorolone was safe and well-tolerated through the highest dose tested (6.0 mg/kg/day) and pharmacokinetics of vamorolone were similar to prednisolone. Using pharmacodynamic biomarkers, the study demonstrated improved safety of vamorolone versus glucocorticoids as shown by reduction of insulin resistance, beneficial changes in bone turnover (loss of increased bone resorption and decreased bone formation only at the highest dose level), and a reduction in adrenal suppression. Exploratory biomarkers of pharmacodynamic efficacy showed an anti-inflammatory mechanism of action and a beneficial effect on plasma membrane stability, as demonstrated by a dose-responsive decrease in serum creatine kinase activity. With an array of pre-selected biomarkers in multiple contexts of use, we demonstrate the development of the first dissociative steroid that preserves anti-inflammatory efficacy and decreases steroid-associated safety concerns. Ongoing extension studies offer the potential to bridge exploratory efficacy biomarkers to clinical outcomes.

Impact of IL-22 and IL-22 receptor alpha 1 polymorphisms on preeclampsia risk in Chinese Han women

Previous studies have indicated that an increased inflammatory response plays an important role in preeclampsia (PE), and rising levels of interleukin (IL)-22 can trigger inflammation and hyperproliferation, leading to increased production of several pro-inflammatory cytokines such as IL-1, IL-6, and IL-8. We aimed to investigate the association between polymorphisms of IL-22 and IL-22 receptor alpha 1 gene (IL-22RA1) and PE in Chinese Han population. Single nucleotide polymorphisms (SNPs) rs2227485 in IL-22 and rs3795299 in IL-22RA were genotyped by Taqman real-time PCR in 1071 PE patients and 1263 control subjects. Differences in genetic distribution were compared between two groups using the chi-square test. Significant differences were observed in genotypic and allelic frequencies of IL-22RA1 rs3795299 between healthy controls and PE patients (P < 0.001 by genotype; P = 0.001, odds ratio = 1.253, 95% confidence interval 1.103-1.424 by allele). There were also significant differences in genotypic and allelic frequencies of rs3795299 between late-onset/mild PE and control groups. In addition, we found obvious statistic difference for the allele of early-onset PE/the genotype of late-onset PE and control subgroups for IL-22 rs2227485. IL-22 rs2227485 and IL-22RA1 rs3795299 may be associated with the development of PE in Chinese Han population. However, further validation is required in other populations, as well as an evaluation of the association of other SNPs in IL-22 and IL-22RA1 with PE.

[Interleukin?22 promotes proliferation of fibroblast?like synoviocytes from patients with rheumatoid arthritis by inducing STAT3 phosphorylation]

OBJECTIVE

To clarify the mechanism by which interleukin?22 (IL?22) promotes the proliferation of fibroblast?like synoviocytes (FLS) from patients with rheumatoid arthritis (RA).

METHODS

FLS were isolated from the synovial tissues of patients with RA and identified by immunohistochemistry for vimentin/CD68. The cells were subcultured and incubated with different concentrations of IL?22 for 24, 48, or 72 h, and their proliferation was examined using MTT assay. After treatment of the cells with IL?22 and AG490, alone or in combination, the expressions of the total and phosphorylated proteins of STAT3, ERK1/2 and P38 were detected with Western blotting.

RESULTS

IL?22 significantly increased the proliferation of FLS in a dose?dependent manner (P<0.05). The total protein of STAT3 in the cells showed no significant changes with extended time of IL?22 treatment (P=0.68), but the expression of phosphorylated STAT3 protein increased significantly (P<0.001). The total and phosphorylated proteins of ERK1/2 and P38 underwent no significant changes after IL?22 treatment (P>0.05). A combined treatment with 50 ng/mL IL?22 and 100 µmol/L AG490 resulted in a significant decrease in the proliferation of FLS as compared with IL?22 treatment alone (P<0.01).

CONCLUSION

IL?22 can dose?dependently promote the proliferation of FLS from patients with RA by inducing phosphorylation of STAT3 protein but not through ERK1/2 or P38 signal pathway.