Interleukin-20 promotes angiogenesis in a direct and indirect manner

Spatial immunophenotypes predict clinical outcome in intrahepatic cholangiocarcinoma

Background & Aims

Intrahepatic cholangiocarcinoma (iCCA) is a severe malignant tumour that shows only modest responses to immunotherapy. We aimed to identify the spatial immunophenotypes of iCCA and delineate potential immune escape mechanisms.

Method

Multiplex immunohistochemistry (mIHC) was performed to quantitatively evaluate the distribution of 16 immune cell subsets in intratumour, invasive margin and peritumour areas in a cohort of 192 treatment-naïve patients with iCCA. Multiregion unsupervised clustering was used to determine three spatial immunophenotypes, and multiomics analyses were carried out to explore functional differences.Results: iCCA displayed a region-specific distribution of immune cell subsets with abundant CD15⁺ neutrophil infiltration in intratumour areas. Three spatial immunophenotypes encompassing inflamed (35%), excluded (35%) and ignored (30%) phenotypes were identified. The inflamed phenotype showed characteristics of abundant immune cell infiltration in intratumour areas, increased PD-L1 expression and relatively favourable overall survival. The excluded phenotype with a moderate prognosis was characterized by immune cell infiltration restricted to the invasive margin or peritumour areas and upregulation of activated hepatic stellate cells, extracellular matrix and Notch signalling pathways. The ignored phenotype, with scarce immune cell infiltration across all subregions, was associated with MAPK signalling pathway elevation and a poor prognosis. The excluded and ignored phenotypes, constituting non-inflamed phenotypes, shared features of an increased angiogenesis score, TGF-β and Wnt-β catenin pathway upregulation and were enriched for BAP1 mutations and FGFR2 fusions.

Conclusion

We identified three spatial immunophenotypes with different overall prognoses in iCCA. Tailored therapies based on the distinct immune evasion mechanisms of the spatial immunophenotypes are needed.

Impact and implications

The contribution of immune cell infiltration in the invasive margin and peritumour areas has been proved. We explored the multiregional immune contexture of 192 patients to identify three spatial immunophenotypes in intrahepatic cholangiocarcinoma (iCCA). By integrating genomic and transcriptomic data, phenotype-specific biological behaviours and potential immune escape mechanisms were analysed. Our findings provide a rationale to develop personalized therapies for iCCA.

Dual Role of Interleukin-20 in Different Stages of Osteoclast Differentiation and Its Osteoimmune Regulation during Alveolar Bone Remodeling

Osteoimmunology mediators are critical to balance osteoblastogenesis and osteoclastogenesis to maintain bone homeostasis. A lot of the osteoimmunology mediators are regulated by interleukin-20 (IL-20). However, little is known about the role of IL-20 in bone remodeling. Here, we showed that IL-20 expression was correlated with osteoclast (OC) activity in remodeled alveolar bone during orthodontic tooth movement (OTM). Ovariectomize (OVX) in rats promoted OC activity and enhanced IL-20 expression, while blocking OC inhibited IL-20 expression in osteoclasts. In vitro, IL-20 treatment promoted survival, inhibited apoptosis of the preosteoclast at the early stages of osteoclast differentiation, and boosted the formation of osteoclasts and their bone resorption function at the late stages. More importantly, anti-IL-20 antibody treatment blocked IL-20-induced osteoclastogenesis and the subsequent bone resorption function. Mechanistically, we showed that IL-20 synergistically acts with RANKL to activate the NF-κB signaling pathway to promote the expression of c-Fos and NFATc1 to promote osteoclastogenesis. Moreover, we found that local injection of IL-20 or anti-IL-20 antibody enhanced osteoclast activity and accelerated OTM in rats, while blocking IL-20 reversed this phenomenon. This study revealed a previously unknown role of IL-20 in regulating alveolar bone remodeling and implies the application of IL-20 to accelerated OTM.

Overexpression of interleukin-20 correlates with favourable prognosis in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma worldwide, accounting for about 40% of cases. The role of cytokines in the pathogenesis of lymphomas has been rarely addressed, although cytokines have a close immunological relationship with lymphocytes. We observed overexpression of interleukin (IL)-20 in reactive germinal centres (GCs) leading us to hypothesise that IL-20 may play a role in lymphomagenesis. In this study, we surveyed for IL-20 expression in various types of lymphoma and found that IL-20 was expressed most frequently in follicular lymphoma (94%), but also in Burkitt lymphoma (81%), mantle cell lymphoma (57%), nodal marginal zone lymphoma (56%), Hodgkin lymphomas (50%), small lymphocytic lymphoma (50%) and diffuse large B-cell lymphoma (DLBCL, 48%). IL-20 was not expressed in extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), lymphoplasmacytic lymphoma, and plasmacytoma. T-cell lymphomas were largely negative for IL-20 expression, except for anaplastic large cell lymphoma (ALCL, 61%), which frequently expressed IL-20, especially in cutaneous ALCL, and showed an inverse association with ALK expression (p=0.024). We further tested IL-20 expression in another large cohort of DLBCL and found IL-20 expression more frequently in germinal centre B-cell (GCB) than in non-GCB subtype [16/26 (62%) versus 24/64 (38%), p=0.038]. In this cohort, IL-20 was associated with a lower rate of extranodal involvement (p=0.009), bone marrow involvement (p=0.040), and better overall survival (p=0.020). Mechanistically, IL-20 overexpression promoted G1 cell cycle arrest and subsequent apoptosis of DLBCL cells and vice versa in vitro. We conclude that IL-20 may be involved in lymphomagenesis and may be useful as a prognostic marker in patients with DLBCL. In addition, IL-20 plays an inhibitory role in DLBCL growth, probably through cell cycle regulation.

Roles of IL-1 and IL-10 family cytokines in the progression of systemic lupus erythematosus: Friends or foes?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that can affect nearly every organ system in the body. Besides genetic and environmental factors, unbalanced pro-inflammatory and anti-inflammatory cytokines contribute to immune dysregulation, trigger an inflammatory response, and induce tissue and organ damage. Inflammatory responses in SLE can be promoted and/or maintained by the availability of cytokines that are overproduced systemically and/or in local tissues. Several key cytokines have been considered potential targets for the reduction of chronic inflammation in SLE. Recent studies indicated that dysregulated production of several cytokines, including those of the IL-1 family and IL-10 family, orchestrate immune activation and self-tolerance, play critical roles in the pathogenesis of SLE. Among IL-1 family cytokines, IL-1, IL-18, IL-33, IL-36, IL-37, and IL-38 had been the most thoroughly investigated in SLE. Additionally, IL-10 family cytokines, IL-10, IL-20, IL-22, IL-26, IL-28, and IL-29 are dysregulated in SLE. Therefore, a better understanding of the initiation and progression of SLE may provide suitable novel targets for therapeutic intervention. In this review, we discuss the involvement of inflammation in the pathogenesis of SLE, with a focus on IL-1 family and IL-10 family cytokines, and highlight pathophysiological approaches and therapeutic potential for treating SLE.

Expression of IL-20 Receptor Subunit β Is Linked to EAE Neuropathology and CNS Neuroinflammation

Considerable clinical evidence supports that increased blood-brain barrier (BBB) permeability is linked to immune extravasation of CNS parenchyma during neuroinflammation. Although BBB permeability and immune extravasation are known to be provoked by vascular endothelial growth factor-A (i.e., VEGF-A) and C-X-C motif chemokine ligand 12 (CXCL12), respectively, the mechanisms that link both processes are still elusive. The interleukin-20 (i.e., IL-20) cytokine signaling pathway was previously implicated in VEGF-mediated angiogenesis and is known to induce cellular response by way of signaling through IL-20 receptor subunit β (i.e., IL-20RB). Dysregulated IL-20 signaling is implicated in many inflammatory pathologies, but it's contribution to neuroinflammation has yet to be reported. We hypothesize that the IL-20 cytokine, and the IL cytokine subfamily more broadly, play a key role in CNS neuroinflammation by signaling through IL-20RB, induce VEGF activity, and enhance both BBB-permeability and CXCL12-mediated immune extravasation. To address this hypothesis, we actively immunized IL-20RB^-/- mice and wild-type mice to induce experimental autoimmune encephalomyelitis (EAE) and found that IL-20RB^-/- mice showed amelioration of disease progression compared to wild-type mice. Similarly, we passively immunized IL-20RB^-/- mice and wild-type mice with myelin-reactive Th1 cells from either IL-20RB^-/- and wild-type genotype. Host IL-20RB^-/- mice showed lesser disease progression than wild-type mice, regardless of the myelin-reactive Th1 cells genotype. Using multianalyte bead-based immunoassay and ELISA, we found distinctive changes in levels of pro-inflammatory cytokines between IL-20RB^-/- mice and wild-type mice at peak of EAE. We also found detectable levels of all cytokines of the IL-20 subfamily within CNS tissues and specific alteration to IL-20 subfamily cytokines IL-19, IL-20, and IL-24, expression levels. Immunolabeling of CNS region-specific microvessels confirmed IL-20RB protein at the spinal cord microvasculature and upregulation during EAE. Microvessels isolated from macaques CNS tissues also expressed IL-20RB. Moreover, we identified the expression of all IL-20 receptor subunits: IL-22 receptor subunit α-1 (IL-22RA1), IL-20RB, and IL-20 receptor subunit α (IL-20RA) in human CNS microvessels. Notably, human cerebral microvasculature endothelial cells (HCMEC/D3) treated with IL-1β showed augmented expression of the IL-20 receptor. Lastly, IL-20-treated HCMEC/D3 showed alterations on CXCL12 apicobasal polarity consistent with a neuroinflammatory status. This evidence suggests that IL-20 subfamily cytokines may signal at the BBB via IL-20RB, triggering neuroinflammation.

IL-20 is involved in obesity by modulation of adipogenesis and macrophage dysregulation

IL-20 is a proinflammatory cytokine of the IL-10 family and involved in several diseases. However, the regulatory role of IL-20 in obesity is not well understood. We explored the function of IL-20 in the pathogenesis of obesity-induced insulin resistance by ELISA, Western blotting and flow cytometry. The therapeutic potential of IL-20 monoclonal antibody 7E for ameliorating diet-induced obesity was analysed in murine models. Higher serum IL-20 levels were detected in obese patients. It was upregulated in leptin-deficient (ob/ob), leptin-resistant (db/db) and high-fat diet (HFD)-induced murine obesity models. In vitro, IL-20 regulated the adipocyte differentiation and the polarization of bone marrow-derived macrophages into proinflammatory M1 type. It also caused inflammation and macrophage retention in adipose tissues by upregulating TNF-α, monocyte chemotactic protein 1 (MCP-1), netrin 1 and unc5b (netrin receptor) expression in macrophages and netrin 1, leptin and MCP-1 in adipocytes. IL-20 promoted insulin resistance by inhibiting glucose uptake in mature adipocytes through the SOCS-3 pathway. In HFD-induced obesity in mice, 7E treatment reduced body weight and improved glucose tolerance and insulin sensitivity; it also reduced local inflammation and the number of M1-like macrophages in adipose tissues. We have identified a critical role of IL-20 in obesity-induced inflammation and insulin resistance, and we conclude that IL-20 may be a novel target for treating obesity and insulin resistance in patients with metabolic disorders.

Functional characterization of an interleukin 20 like homologue in grass carp Ctenopharyngodon idella

IL-20 is a pleiotropic cytokine that belongs to the IL-10 family and plays an important biological role in tissue homeostasis and regulation of host immune defenses. IL-20 homologues have recently been discovered in fish, but their functions have not been studied. In this study, an IL-20 like (IL-20L) cytokine was cloned in grass carp (Ctenopharyngodon idella) and its bioactivities were investigated. Expression analysis showed that the CiIL-20L gene was constitutively expressed in tissues with the highest expression detected in the head kidney. It was upregulated in the head kidney after infection with Flavobactrium columnare (F. cloumnare) and grass carp reovirus II (GCRV II). The recombinant CiIL-20L produced in E. coli cells was shown to be effective in inducing the expression of Th cytokine genes (IFN-γ, IL-4/13A, IL-4/13B and IL-10), macrophage marker genes (arginase 2, IRF4, KLF4 and SOCS3) and inflammatory genes (IL-1β, IL-6, IL-8 and TNFα) in the head kidney leukocytes when stimulated at 12 h. Long term culture (6 days) of head kidney macrophages in the presence of CiIL-20L leads to high expression of IRF4, TGFβ1 and arginase 2. Our data suggest that IL-20 may play regulatory roles in promoting Th responses, macrophage differentiation and inflammation.

The role of interleukin-10 family members in cardiovascular diseases

Interleukin (IL)-10 cytokine family members, including IL-10, IL-19, IL-20, IL-22, IL-24, IL-26 and the distantly related IL-28A, IL-28B, and IL-29, play critical roles in the regulation of inflammation. The occurrence and progression of cardiovascular diseases closely correlate with the regulation of inflammation, which may provide novel strategies for the treatment of cardiovascular diseases. In recent years, studies have focused on the association between the IL-10 cytokine family and the physiological and pathological progression of cardiovascular diseases. The aim of this review is to summarize relevant studies and clarify whether the IL-10 cytokine family contributes to the regulation of cardiovascular diseases.

IL-20 antagonist suppresses PD-L1 expression and prolongs survival in pancreatic cancer models

Pancreatic ductal adenocarcinoma (PDAC) and cancer-associated cachexia (CAC) are multifactorial and characterized by dysregulated inflammatory networks. Whether the proinflammatory cytokine IL-20 is involved in the complex networks of PDAC and CAC remains unclear. Here, we report that elevated IL-20 levels in tumor tissue correlate with poor overall survival in 72 patients with PDAC. In vivo, we establish a transgenic mouse model (KPC) and an orthotopic PDAC model and examine the therapeutic efficacy of an anti-IL-20 monoclonal antibody (7E). Targeting IL-20 not only prolongs survival and attenuates PD-L1 expression in both murine models but also inhibits tumor growth and mitigates M2-like polarization in the orthotopic PDAC model. Combination treatment with 7E and an anti-PD-1 antibody shows better efficacy in inhibiting tumor growth than either treatment alone in the orthotopic PDAC model. Finally, 7E mitigates cachexic symptoms in CAC models. Together, we conclude IL-20 is a critical mediator in PDAC progression.

The pro-inflammatory cytokine IL-20 promotes tumor growth in several cancer types. Here, the authors show that high levels of IL-20 are associated with poor survival in patients with pancreatic ductal adenocarcinoma (PDAC) and that IL-20 blockade reduces tumor growth and alleviates cachexia symptoms in mouse models of PDAC.

First-trimester trophoblasts obtained by chorionic villus sampling maintain tolerogenic and proteomic features in successful pregnancies despite a history of unexplained recurrent pregnancy loss

PROBLEM

While there are several known causes for recurrent pregnancy loss (RPL), about 50% are unexplained (uRPL), and in these cases, an aberrant immune regulation seems to be involved. Although fetally derived trophoblast cells have a key role in immune regulation, it is difficult to study their immune function during pregnancy, and it is not known whether trophoblast function may be an inherent aberration in uRPL or whether it is associated with the outcome of the current pregnancy.

METHOD OF STUDY

Chorionic villus sampling (CVS) was performed for clinical indications at 12 weeks of gestation. Superfluous materials, divided in small explants, were cultured for 20-24 hours, and supernatants (conditioned medium) were collected from 36 women with singleton normal pregnancies, of whom 9 women had a history of RPL. The secreted immune protein profile was measured by proximity extension assay, and the conditioned medium was further used in functional ex vivo models to assess ability to polarize blood monocytes and CD4⁺ T cells into immune regulatory phenotypes, as detected by flow cytometry.

RESULTS

Conditioned medium from chorionic villi, human fetally derived placental tissue, was able to induce a decidual-type of M2-like macrophages, as well as an expansion of Treg cells ex vivo, both in women with uRPL and in control women. The preserved immunological properties were confirmed by a maintained immune protein profile in RPL compared with controls.

CONCLUSION

Trophoblasts in an ex vivo model maintain tolerogenic and proteomic profile features in successful pregnancies, despite a previous history of RPL.

The expression of interleukin 20 increases in plasma and aortic tissues from patients with acute aortic dissection

OBJECTIVE

Acute aortic dissection (AAD) is the most devasting cardiovascular disease associated with high mortality. The occurrence and progression of AAD can be regulated by inflammatory processes, and further understanding of this inflammatory pathogenesis may improve the treatment of AAD. Interleukin 20 (IL-20), as an inflammatory mediator, has been demonstrated to be associated with several inflammatory diseases. However, the association between IL and 20 and AAD is still unknown.

METHODS

Five aortic dissection tissue samples and five control aortic tissue samples were evaluated in our study. The expression of IL-20 and its receptor subunits (IL-20Rα and IL-20Rβ) was detected by immunofluorescence staining. From January 2018 to March 2018, 70 consecutive AAD patients and 25 non-AAD (NAD) patients were enrolled in this study. Diagnosis was based on computed tomography angiography (CTA) results. Blood samples were obtained from the patients on the first day of hospitalization. Plasma IL-20, TNF-α and IL-6 concentrations were evaluated with enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

The expression levels of IL-20 and its receptor subunits (IL-20Rα and IL-20Rβ) were increased in the sites of arterial wall dissection in the AAD patients. In a separate group, the plasma IL-20, TNF-α and IL-6 concentrations were significantly higher in the AAD patients than in the non-AAD patients. Spearman's correlation analysis showed that plasma IL-20 was positively correlated with plasma TNF-α and IL-6, D-dimer, C-reaction protein (CRP), creatinine, fasting blood glucose, systolic blood pressure (SBP), and diastolic blood pressure (DBP). Multiple linear regression revealed that IL-20, in addition to IL-6, glucose, CRP and D-dimer, was independently associated with the presence of AAD.

CONCLUSION

IL-20 was closely associated with the presence of AAD. IL-20 may contribute to the inflammatory pathogenesis of AAD.

Anti-IL-20 antibody improved motor function and reduced glial scar formation after traumatic spinal cord injury in rats

BACKGROUND

Spinal cord injury (SCI) causes devastating neurological consequences, which can result in partial or total paralysis. Irreversible neurological deficits and glial scar formation are characteristic of SCI. Inflammatory responses are a major component of secondary injury and play a central role in regulating the pathogenesis of SCI. IL-20 is a proinflammatory cytokine involved in renal fibrosis and liver cirrhosis through its role in upregulating TGF-β1 production. However, the role of IL-20 in SCI remains unclear. We hypothesize that IL-20 is upregulated after SCI and is involved in regulating the neuroinflammatory response.

METHODS

The expression of IL-20 and its receptors was examined in SCI rats. The regulatory roles of IL-20 in astrocytes and neuron cells were examined. The therapeutic effects of anti-IL-20 monoclonal antibody (mAb) 7E in SCI rats were evaluated.

RESULTS

Immunofluorescence staining showed that IL-20 and its receptors were expressed in astrocytes, oligodendrocytes, and microglia in the spinal cord after SCI in rats. In vitro, IL-20 enhanced astrocyte reactivation and cell migration in human astrocyte (HA) cells by upregulating glial fibrillary acidic protein (GFAP), TGF-β1, TNF-α, MCP-1, and IL-6 expression. IL-20 inhibited cell proliferation and nerve growth factor (NGF)-derived neurite outgrowth in PC-12 cells through Sema3A/NRP-1 upregulation. In vivo, treating SCI rats with anti-IL-20 mAb 7E remarkably inhibited the inflammatory responses. 7E treatment not only improved motor and sensory functions but also improved spinal cord tissue preservation and reduced glial scar formation in SCI rats.

CONCLUSIONS

IL-20 might regulate astrocyte reactivation and axonal regeneration and result in the secondary injury in SCI. These findings demonstrated that IL-20 may be a promising target for SCI treatment.

IL-20 in Acute Kidney Injury: Role in Pathogenesis and Potential as a Therapeutic Target

Acute kidney injury (AKI) causes over 1 million deaths worldwide every year. AKI is now recognized as a major risk factor in the development and progression of chronic kidney disease (CKD). Diabetes is the main cause of CKD as well. Renal fibrosis and inflammation are hallmarks in kidney diseases. Various cytokines contribute to the progression of renal diseases; thus, many drugs that specifically block cytokine function are designed for disease amelioration. Numerous studies showed IL-20 functions as a pro-inflammatory mediator to regulate cytokine expression in several inflammation-mediated diseases. In this review, we will outline the effects of pro-inflammatory cytokines in the pathogenesis of AKI and CKD. We also discuss the role of IL-20 in kidney diseases and provide a potential therapeutic approach of IL-20 blockade for treating renal diseases.

IL-20 promotes hypoxia/reoxygenation-induced mitochondrial dysfunction and apoptosis in cardiomyocytes by upregulating oxidative stress by activating the PKC/NADPH oxidase pathway

Acute myocardial infarction (AMI) is the maximum critical cardiovascular event and causes high morbidity and mortality worldwide. The ischemia and reperfusion that occur in AMI cause apoptosis and cellular dysfunction in cardiomyocytes. IL-20, an IL-10 family member, is involved in various inflammatory diseases. Therefore, we sought to elucidate the role of IL-20 in the infarcted heart following ischemia/reperfusion (I/R) injury. We found that IL-20 and its receptors, IL-20R1 and IL-20R2, were increased in H2C2 cardiomyoblast cells and ventricular tissues subjected to hypoxia/reoxygenation (H/R) stimulation. The presence of IL-20 further inhibited the cell viability of H9C2 cells and primary cardiomyocytes. Our results suggested that IL-20 elicited an increase in Ca²⁺ and activation of the PKC/NADPH oxidase pathway, leading to the elevation of oxidase stress and downregulation of AKT. Furthermore, we demonstrated that IL-20 was able to mediate H/R-induced apoptosis via PKC/NADPH oxidase/AKT signaling. Our findings implied that IL-20 was responsive to H/R stress in vitro and in rat hearts undergoing I/R injury, and this upregulation of IL-20 may contribute to the apoptosis of cardiomyocytes.

Effects of IL-1β, IL-20, and BMP-2 on Intervertebral Disc Inflammation under Hypoxia

Intervertebral disc (IVD) is an avascular tissue under hypoxic condition after adulthood. Our previous data showed that inflammatory cytokines (interleukin (IL)-1β), IL-20, and bone morphogenetic protein-2 (BMP-2) play important roles in the healing process after disc injury. In the current study, we investigated whether IL-1β, IL-20, or BMP-2 modulate the expression of pro-inflammatory cytokines, chemotaxis factor, and angiogenesis factor on IVD cells under hypoxia. IVD cells were isolated from patients with intervertebral disc herniation (HIVD) at the levels of L4–5 and L5–S1. We found that the expression of IL-1β, IL-20, BMP-2, hypoxia-inducible factor (HIF)-1α, IL-6, IL-8, angiogenetic factor (vascular endothelial growth factor (VEGF)), chemotactic factor (monocyte chemoattractant protein 1 (MCP-1)), and matrix metalloproteinase-3 (MMP-3) was upregulated in IVD cells under hypoxia conditions. In addition, IL-1β upregulated the expression of pro-inflammatory cytokines (IL-6 and IL-8), VEGF, MCP-1, and disc degradation factor (MMP-3) in IVD cells under hypoxia conditions. IL-20 upregulated MCP-1 and VEGF expression. BMP-2 also upregulated the expression of MCP-1, VEGF, and IL-8 in IVD cells under hypoxia conditions. Treatment with antibody against IL-1β decreased VEGF and MMP-3 expression, while treatment with IL-20 or BMP-2 antibodies decreased MCP-1, VEGF, and MMP-3 expression. Moreover, IL-1β modulated both the expression of IL-20 and BMP-2, but IL-20 only modulated BMP-2 either under a hypoxic or normoxic condition. Therefore, we concluded that the inflammation, chemotaxis, matrix degradation, and angiogenesis after disc herniation are influenced by the hypoxic condition and controlled by IL-1β, IL-20, and BMP-2.

Interleukin-10 Family Cytokines Immunobiology and Structure

The Interleukin (IL)-10 cytokine family includes IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26, which are considered as Class 2α-helical cytokines. IL-10 is the most important cytokine in suppressing pro-inflammatory responses in all kinds of autoimmune diseases and limiting excessive immune responses. Due to protein structure homology and shared usage of receptor complexes as well as downstream signaling pathway, other IL-10 family cytokines also show indispensable functions in immune regulation, tissue homeostasis, and host defense. In this review, we focus on immune functions and structures of different cytokines in this family and try to better understand how their molecular mechanisms connect to their biological functions. The molecular details regarding their actions also provide useful information in developing candidate immune therapy reagents for a variety of diseases.

The roles of IL-19 and IL-20 in the inflammation of degenerative lumbar spondylolisthesis

Background

Degenerative lumbar spondylolisthesis (DLS) is a major cause of spinal canal stenosis and is often related to lower back pain. IL-20 is emerging as a potent angiogenic, chemotactic, and proinflammatory cytokine related to several chronic inflammatory bone disorders likes intervertebral disc herniation, rheumatoid arthritis (RA), osteoporosis, and bone fracture. IL-19 also acts as a proinflammatory cytokine in RA. The aim of the present study was to investigate whether IL-19 and IL-20 are involved in DLS and compare three different tissues including disc, facet joint, and ligamentum flavum of patients with DLS to verify which tissue is affected more by inflammation.

Methods

Disc, facet joint and ligamentum flavum from 13 patients with DLS was retrieved, and the expression pattern of IL-19, IL-20, IL-20R1, IL-20R2, TNF-α, IL-1β, and MCP-1 was evaluated using immunohistochemical staining with specific antibodies. The disc cells were isolated and incubated with IL-19 and IL-20 under CoCl₂-mimicked hypoxic conditions to analyze the proinflammatory cytokine expression pattern using real-time quantitative PCR with specific primers.

Results

IL-19 and IL-20 were positively stained and accompanied by abundant expression of TNF-α, IL-1β, and MCP-1 in facet joints of DLS patients. IL-19 and IL-20's receptors (IL-20R1 and IL-20R2) were expressed on chondrocytes and fibrocytes/fibroblasts in facet joint and ligamentum flavum tissues from patients with DLS. There was a significant correlation between the expression of IL-20 and IL-1β in facet joint. In vitro assay, IL-19 and IL-20 upregulated the expression of IL-1β, IL-6, TNF-α, IL-8, VEGF, and MCP-1 in primary cultured DLS disc cells under CoCl₂-mimicked hypoxic conditions.

Conclusions

IL-19, IL-20, and their receptors as well as proinflammatory cytokines (TNF-α, IL-1β, and MCP-1) were expressed more in facet joints than the other tissues in patients with DLS; therefore, the etiology of inflammation might be more facet-centric. IL-19 and IL-20 induced proinflammatory cytokine expression in disc cells and might play a role in the pathogenesis of DLS.

Psammomys obesus: a Natural Diet-Controlled Model for Diabetes and Cardiovascular Diseases

PURPOSE OF REVIEW

This review specifically summarises and reports terrestrial mammals of the gerbil subfamily, known as Israeli sand rats or Psammomys obesus (P. obesus) as a diet-controlled, unique, polygenic rodent model for research in the areas of obesity, type 2 diabetes, and cardiovascular diseases. The animal model closely mimics phenotypic and pathophysiological resemblance with human populations.

RECENT FINDINGS

The physiological status and biochemical composition in P. obesus can be manipulated effectively by controlling its nutritional intake, making it a natural model for cardiovascular and diabetic research. Humans exhibit remarkable disparity in physiology and pathology, which are inter-dependent factors. However, variations in these factors in most animal models currently being used for cardiovascular/diabetes research are insignificant. Consequently, it is a necessity to identify and develop animal models exhibiting physiological variations mimicking human pathological conditions. We have compiled research developments conducted with this rodent model manifesting pathophysiology, closely mimicking that in human beings, thereby enabling better translation of novel therapeutic and diagnostic discoveries.

The role of IL-20 in chronic kidney disease and diabetic nephropathy: Pathogenic and therapeutic implications

Chronic kidney disease and its complications are a major public health problem worldwide. Diabetic nephropathy has become the main contributing cause of terminal renal failure. There are now evidences that different inflammatory molecules, including proinflammatory cytokines, play a critical role in the development of microvascular diabetic complications, including nephropathy. IL-20 is emerging as a potent angiogenic, chemotactic, and proinflammatory cytokine related to several chronic inflammatory disorders likes psoriasis, atherosclerosis, and renal failure. This review discusses the role of IL-20 as a pathogenic factor in renal injury, focusing on chronic kidney disease and diabetic nephropathy, and describes potential treatment strategies based on modulation of IL-20's function.

IL-20 bone diseases involvement and therapeutic target potential

BACKGROUND

Millions of people around the world suffer from bone disorders, likes osteoporosis, rheumatoid arthritis (RA), and cancer-induced osteolysis. In general, the bone remodeling balance is determined by osteoclasts and osteoblasts, respectively responsible for bone resorption and bone formation. Excessive inflammation disturbs the activities of these two kinds of cells, typically resulting in the bone loss.

MAIN BODY

IL-20 is emerging as a potent angiogenic, chemotactic, and proinflammatory cytokine related to several chronic inflammatory disorders likes psoriasis, atherosclerosis, cancer, liver fibrosis, and RA. IL-20 has an important role in the regulation of osteoclastogenesis and osteoblastogenesis and is upregulated in several bone-related diseases. The anti-IL-20 monoclonal antibody treatment has a therapeutic potential in several experimental disease models including ovariectomy-induced osteoporosis, cancer-induced osteolysis, and bone fracture.

CONCLUSION

This review article provides an overview describing the IL-20's biological functions in the common bone disorders and thus providing a novel therapeutic strategy in the future.

IL-19 and Other IL-20 Family Member Cytokines in Vascular Inflammatory Diseases

Cardiovascular disease remains a major medical and socioeconomic burden in developed and developing countries and will increase with an aging and increasingly sedentary society. Many vascular diseases and atherosclerotic vascular disease, in particular, are essentially inflammatory disorders, involving multiple cell types. Communication between these cells is initiated and sustained by a complex network of cytokines and their receptors. The interleukin (IL)-20 family members, IL-19, IL-20, IL-22, and IL-24, initiate, sustain, and drive the progression of vascular disease. They are important in vascular disease as they facilitate a bidirectional cross-talk between resident vascular cells with immune cells. These cytokines are grouped into the same family based on shared common receptor subunits and signaling pathways. This communication is varied and can result in exacerbation, attenuation, and even repair of the vasculature. We will briefly review what is known about IL-20, IL-22, and IL-24 in cardiovascular biology. Because IL-19 is the most studied member of this family in terms of its role in vascular pathophysiological processes, the major emphasis of this review will focus on the expression and atheroprotective roles of IL-19 in vascular inflammatory disease.

Anti-IL-20 monoclonal antibody inhibited tumor growth in hepatocellular carcinoma

Interleukin (IL)-20 is a proinflammatory cytokine involved in rheumatoid arthritis, atherosclerosis, and osteoporosis. However, the role of IL-20 in hepatocellular carcinoma (HCC) is unclear. We explored the function of IL-20 in HCC. Tumor tissue samples were analyzed the expression of IL-20 and cyclin D1 by using immunohistochemistry staining and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. To examine the role of anti-IL-20 monoclonal antibody (7E) in tumor growth, BALB/c mice was injected with ML-1 cells and treated with 7E. HCC tumor tissue expressed higher levels of IL-20 than did non-tumor tissue. High IL-20 expression in HCC was correlated with poor overall survival (relative risk:>3). IL-20 and cyclin D1 expression were also highly correlated in HCC patient specimens and 3 human HCC cell lines. IL-20 also increased cell proliferation and migration, and it regulated matrix metalloproteinase (MMP)-13, tumor necrosis factor (TNF)-α, cyclin D1, and p21^WAF1 expression in ML-1 cells. 7E attenuated tumor growth in mice inoculated with ML-1 cells. The expression of cyclin D1, TNF-α, MMP-9, and vascular endothelial growth factor was significantly inhibited after 7E treatment. The findings of this study suggest that IL-20 plays a role in the tumor progression of HCC.

Interleukin-20 targets podocytes and is upregulated in experimental murine diabetic nephropathy

Interleukin (IL)-20, a proinflammatory cytokine of the IL-10 family, is involved in acute and chronic renal failure. The aim of this study was to elucidate the role of IL-20 during diabetic nephropathy development. We found that IL-20 and its receptor IL-20R1 were upregulated in the kidneys of mice and rats with STZ-induced diabetes. In vitro, IL-20 induced MMP-9, MCP-1, TGF-β1 and VEGF expression in podocytes. IL-20 was upregulated by hydrogen peroxide, high-dose glucose and TGF-β1. In addition, IL-20 induced apoptosis in podocytes by activating caspase-8. In STZ-induced early diabetic nephropathy, IL-20R1-deficient mice had lower blood glucose and serum BUN levels and a smaller glomerular area than did wild-type controls. Anti-IL-20 monoclonal antibody (7E) treatment reduced blood glucose and the glomerular area and improved renal functions in mice in the early stage of STZ-induced diabetic nephropathy. ELISA showed that the serum IL-20 level was higher in patients with diabetes mellitus than in healthy controls. The findings of this study suggest that IL-20 induces cell apoptosis of podocytes and plays a role in the pathogenesis of early diabetic nephropathy.

Ell3 stabilizes p53 following CDDP treatment via its effects on ubiquitin-dependent and -independent proteasomal degradation pathways in breast cancer cells

The tumor suppressor protein p53 is unstable in quiescent cells and undergoes proteosomal degradation. Under conditions of cellular stress, p53 is rapidly stabilized by post-translational modification, thereby escaping degradation and translocating to the nucleus where it activates genes related to cell cycle arrest or apoptosis. Here, we report that the transcription elongation factor Ell3 sensitizes luminal type-cancer cell line, MCF7, which have wild-type p53, to the chemotherapeutic agent cis-diamminedichloroplatinum(II) (CDDP) by stabilizing p53. Overexpression of Ell3 in MCF7 cells suppressed the MDM2-mediated ubiquitin-dependent degradation pathway. In addition, Ell3 promoted binding of p53 to NADH quinone oxidoreductase 1, which is linked to the ubiquitin-independent degradation of p53. We found that Ell3 activates interleukin-20 (IL20) expression, which is linked to the ERK1/2 signaling pathway. Chemical inhibition of ERK1/2 signaling or molecular suppression of IL20 revealed that the ERK1/2 signaling pathway and IL20 are the main causes of p53 stabilization in Ell3-overexpressing MCF7 cells. These findings suggest that the ERK1/2 pathway can be targeted in the rational development of therapies to induce chemosensitization of breast cancer cells.

Interleukin-19 induces angiogenesis in the absence of hypoxia by direct and indirect immune mechanisms

Neovascularization and inflammation are independent biological processes but are linked in response to injury. The role of inflammation-dampening cytokines in the regulation of angiogenesis remains to be clarified. The purpose of this work was to test the hypothesis that IL-19 can induce angiogenesis in the absence of tissue hypoxia and to identify potential mechanisms. Using the aortic ring model of angiogenesis, we found significantly reduced sprouting capacity in aortic rings from IL-19(-/-) compared with wild-type mice. Using an in vivo assay, we found that IL-19(-/-) mice respond to vascular endothelial growth factor (VEGF) significantly less than wild-type mice and demonstrate decreased capillary formation in Matrigel plugs. IL-19 signals through the IL-20 receptor complex, and IL-19 induces IL-20 receptor subunit expression in aortic rings and cultured human vascular smooth muscle cells, but not endothelial cells, in a peroxisome proliferator-activated receptor-γ-dependent mechanism. IL-19 activates STAT3, and IL-19 angiogenic activity in aortic rings is STAT3-dependent. Using a quantitative RT-PCR screening assay, we determined that IL-19 has direct proangiogenic effects on aortic rings by inducing angiogenic gene expression. M2 macrophages participate in angiogenesis, and IL-19 has indirect angiogenic effects, as IL-19-stimulated bone marrow-derived macrophages secrete proangiogenic factors that induce greater sprouting of aortic rings than unstimulated controls. Using a quantitative RT-PCR screen, we determined that IL-19 induces expression of angiogenic cytokines in bone marrow-derived macrophages. Together, these data suggest that IL-19 can promote angiogenesis in the absence of hypoxia by at least two distinct mechanisms: 1) direct effects on vascular cells and 2) indirect effects by stimulation of macrophages.

Macrophages: An Inflammatory Link Between Angiogenesis and Lymphangiogenesis

Angiogenesis and lymphangiogenesis often occur in response to tissue injury or in the presence of pathology (e.g., cancer), and it is these types of environments in which macrophages are activated and increased in number. Moreover, the blood vascular microcirculation and the lymphatic circulation serve as the conduits for entry and exit for monocyte-derived macrophages in nearly every tissue and organ. Macrophages both affect and are affected by the vessels through which they travel. Therefore, it is not surprising that examination of macrophage behaviors in both angiogenesis and lymphangiogenesis has yielded interesting observations that suggest macrophages may be key regulators of these complex growth and remodeling processes. In this review, we will take a closer look at macrophages through the lens of angiogenesis and lymphangiogenesis, examining how their dynamic behaviors may regulate vessel sprouting and function. We present macrophages as a cellular link that spatially and temporally connects angiogenesis with lymphangiogenesis, in both physiological growth and in pathological adaptations, such as tumorigenesis. As such, attempts to therapeutically target macrophages in order to affect these processes may be particularly effective, and studying macrophages in both settings will accelerate the field's understanding of this important cell type in health and disease.

Characterization and Comparative Analysis of the Milk Transcriptome in Two Dairy Sheep Breeds using RNA Sequencing

This study presents a dynamic characterization of the sheep milk transcriptome aiming at achieving a better understanding of the sheep lactating mammary gland. Transcriptome sequencing (RNA-seq) was performed on total RNA extracted from milk somatic cells from ewes on days 10, 50, 120 and 150 after lambing. The experiment was performed in Spanish Churra and Assaf breeds, which differ in their milk production traits. Nearly 67% of the annotated genes in the reference genome (Oar_v3.1) were expressed in ovine milk somatic cells. For the two breeds and across the four lactation stages studied, the most highly expressed genes encoded caseins and whey proteins. We detected 573 differentially expressed genes (DEGs) across lactation points, with the largest differences being found, between day 10 and day 150. Upregulated GO terms at late lactation stages were linked mainly to developmental processes linked to extracellular matrix remodeling. A total of 256 annotated DEGs were detected in the Assaf and Churra comparison. Some genes selectively upregulated in the Churra breed grouped under the endopeptidase and channel activity GO terms. These genes could be related to the higher cheese yield of this breed. Overall, this study provides the first integrated overview on sheep milk gene expression.

Neutralizing Anti-IL20 Antibody Treatment Significantly Modulates Low Grade Inflammation without Affecting HbA1c in Type 2 Diabetic db/db Mice

Low grade inflammation is present in pre-clinical and human type 2 diabetes. In this process, several cytokines like IL-1β and inflammatory cells like macrophages are activated and demonstrated to participate to the disease initiation and progression. IL-20 is a cytokine known to play non-redundant roles in progression of several inflammatory diseases. To address the therapeutic effect of inhibiting the IL-20 pathway in diabetes, diabetic db/db mice were treated with neutralizing anti-IL20 antibodies in vivo and both metabolic and inflammatory parameters were followed. Diabetic islets expressed the IL-20 cytokine and all IL-20 receptor components in elevated levels compared to resting non-diabetic islets. Islets were responsive to ex vivo IL-20 stimulation measured as SOCS induction and KC and IL-6 production. Neutralizing anti-IL20 treatment in vivo had no effect on HbA1c or weight although the slope of blood glucose increase was lowered. In contrast, anti-IL20 treatment significantly reduced the systemic low-grade inflammation and modulated the local pancreatic immunity. Significant reduction of the systemic IL-1β and MCP-1 was demonstrated upon anti-IL20 treatment which was orchestrated with a reduced RANTES, IL-16 and IL-2 but increased TIMP-1, MCP-1 and IL-6 protein expression locally in the pancreas. Interestingly, anti-IL20 treatment induced an expansion of the myeloid suppressor CD11bGr1int macrophage while reducing the number of CD8 T cells. Taken together, anti-IL20 treatment showed moderate effects on metabolic parameters, but significantly altered the low grade local and systemic inflammation. Hence, future combination therapies with anti-IL20 may provide beneficial therapeutic effects in type 2 diabetes through a reduction of inflammation.

Interleukin-19 increases angiogenesis in ischemic hind limbs by direct effects on both endothelial cells and macrophage polarization

Hypoxia in ischemic limbs typically initiates angiogenic and inflammatory factors to promote angiogenesis in attempt to restore perfusion. There is a gap in our knowledge concerning the role of anti-inflammatory interleukins in angiogenesis, macrophage polarization, and endothelial cell activation. Interleukin-19 is a unique anti-inflammatory Th2 cytokine that promotes angiogenic effects in cultured endothelial cells (EC); the purpose of this study was to characterize a role for IL-19 in restoration of blood flow in hind-limb ischemia, and define potential mechanisms. Hind limb ischemia was induced by femoral artery ligation, and perfusion quantitated using Laser Doppler Perfusion Imaging (LDPI). Wild type mice which received i.p. injections of rIL-19 (10ng/g/day) showed significantly increased levels of perfusion compared to PBS controls. LDPI values were significantly decreased in IL-19(-/-) mice when compared to wild type mice. IL-19(-/-) mice injected with rIL-19 had significantly increased LDPI compared with PBS control mice. Significantly increased capillary density was quantitated in rIL-19 treated mice, and significantly less capillary density in IL-19(-/-) mice. Multiple cell types participate in IL-19 induced angiogenesis. IL-19 treatment of human microvascular EC induced expression of angiogenic cytokines. M2 macrophage marker and VEGF-A expression were significantly increased in macrophage and the spleen from rIL-19 injected mice, and M1 marker expression was significantly increased in the spleen from IL-19(-/-) compared with controls. Plasma VEGF-A levels are higher in rIL-19 injected mice. IL-19 decreased the expression of anti-angiogenic IL-12 in the spleen and macrophage. This study is the first to implicate IL-19 as a novel pro-angiogenic interleukin and suggests therapeutic potential for this cytokine.

IL-20 and IL-20R1 antibodies protect against liver fibrosis

Interleukin (IL)-20 is a proinflammatory cytokine of the IL-10 family and involved in rheumatoid arthritis, atherosclerosis, stroke, and osteoporosis. However, the pathophysiological roles of IL-20 in liver injury have not been extensively studied. We explored the involvement of IL-20 in liver injury and the therapeutic potential of IL-20 antagonists for treating liver fibrosis. Compared with normal liver tissue from healthy individuals, the amount of IL-20 was much higher in hepatocytes and hepatic stellate cells in liver biopsies from patients with fibrosis, cirrhosis, and hepatocellular carcinoma. Carbon tetrachloride (CCl4) treatment induced IL-20 that further up-regulated the expression of transforming growth factor (TGF)-β1 and p21(WAF1) and resulted in cell cycle arrest in the Clone-9 rat hepatocyte cell line. IL-20 activated quiescent rat hepatic stellate cells (HSCs) and up-regulated TGF-β1 expression. IL-20 also increased TGF-β1, tumor necrosis factor (TNF)-α, and type I collagen (Col-I) expression, and promoted the proliferation and migration of activated HSCs. Serum IL-20 was significantly elevated in mice with short-term and long-term CCl4 -induced liver injury. In mice with short-term liver injury, anti-IL-20 monoclonal antibody (7E) and anti-IL-20 receptor (IL-20R1) monoclonal antibody (51D) attenuated hepatocyte damage caused by CCl4, TGF-β1, and chemokine production. In mice with long-term liver injury, 7E and 51D inhibited CCl4 -induced cell damage, TGF-β1 production, liver fibrosis, HSC activation, and extracellular matrix accumulation, which was caused by the reduced expression of tissue inhibitors of metalloproteinases as well as increased metalloproteinase expression and Col-I production. IL-20R1-deficient mice were protected from short-term and long-term liver injury.

CONCLUSION

We identified a pivotal role of IL-20 in liver injury and showed that 7E and 51D may be therapeutic for liver fibrosis.

Decreased interleukin-20 expression in scleroderma skin contributes to cutaneous fibrosis

OBJECTIVE

To clarify the role of interleukin-20 (IL-20) in the regulatory mechanism of extracellular matrix expression and to determine the contribution of IL-20 to the phenotype of systemic sclerosis (SSc).

METHODS

Protein and messenger RNA (mRNA) levels of collagen, Fli-1, IL-20, and IL-20 receptor (IL-20R) were analyzed using polymerase chain reaction (PCR) array, immunoblotting, immunohistochemical staining, enzyme-linked immunosorbent assay, and real-time PCR.

RESULTS

PCR array revealed that IL-20 decreased gene expression of α2(I) collagen (0.03-fold), Smad3 (0.02-fold), and endoglin (0.05-fold) in cultured normal dermal fibroblasts. Fli-1 protein expression was induced by IL-20 (~2-fold). The inhibition of collagen by IL-20, the induction of Fli-1 by IL-20, and the reduction of Smad3 and endoglin by IL-20 were also observed in SSc fibroblasts. Serum IL-20 levels were reduced only slightly in SSc patients but were significantly decreased in patients with scleroderma spectrum disorders (the prodromal stage of SSc) compared with those in normal subjects (111.3 pg/ml versus 180.4 pg/ml; P < 0.05). On the other hand, IL-20 mRNA expression in SSc skin was decreased compared with that in normal skin (P < 0.05), which may result in the induction of collagen synthesis in SSc dermal fibroblasts. IL-20R was expressed in normal and SSc fibroblasts. Moreover, IL-20 supplementation by injection into the skin reversed skin fibrosis induced by bleomycin in mice (~0.5-fold).

CONCLUSION

IL-20 reduces basal collagen transcription via Fli-1 induction, while down-regulation of Smad3 and endoglin may cancel the effect of transforming growth factor β in SSc fibroblasts. To confirm the therapeutic value of IL-20 and IL-20R, their function and expression in vivo should be further studied.

The role of the IL-22/IL-22R1 axis in cancer

Interleukin-22 (IL-22) is an IL-10 family cytokine produced by T cells and innate lymphoid cells. The IL-22 signaling pathway orchestrates mucosal immune defense and tissue regeneration through pleiotropic effects including pro-survival signaling, cell migration, dysplasia and angiogenesis. While these functions can prevent initial establishment of tumors, they can also be hijacked by aggressive cancers to enhance tumor growth and metastasis. Thus, the role of the IL-22/IL-22R1 axis in cancer is complex and context-specific. Evidence of IL-22 involvement manifests as dysregulation of IL-22 expression and signaling in patients with many common cancers including those of the gut, skin, lung and liver. Unlike other cancer-associated cytokines, IL-22 has restricted tissue specificity as its unique receptor IL-22R1 is exclusively expressed on epithelial and tissue cells, but not immune cells. This makes it an attractive target for therapy as there is potential achieve anti-tumor immunity with fewer side effects. This review summarizes current findings on functions of IL-22 in association with general mechanisms for tumorigenesis as well as specific contributions to particular cancers, and ponders how best to approach further research in the field.

The Therapeutic Potential of Anti-Interleukin-20 Monoclonal Antibody

Interleukin (IL)-20, a member of the IL-10 family of cytokines, was discovered in 2001. IL-20 acts on multiple cell types by activating on a heterodimer receptor complex of either IL-20R1–IL-20R2 or IL-22R1–IL-20R2. Recent evidence indicates that IL-20's interaction with its receptors might have proinflammatory effects on chronic inflammatory diseases, particularly rheumatoid arthritis (RA), osteoporosis, and breast cancer. Updated information about IL-20, such as its identification, expression, receptors, signaling, and biological activities, is illustrated in this review based on our research and the data available in the literature. IL-20 is a pleiotropic cytokine, which promotes inflammation, angiogenesis, and chemotaxis. IL-20 also regulates osteoclast differentiation by altering the receptor activator of NF-κB (RANK) and RANK ligand (RANKL) axis. Inflammation, angiogenesis, and osteoclastogenesis are critical for the pathogenesis of RA, osteoporosis, and breast cancer-induced osteolysis. Based on the in vitro and in vivo data and clinical samples, we demonstrated that IL-20 plays pivotal roles in these three diseases. In experimental models, anti-IL-20 monoclonal antibody ameliorates arthritis severity, protects against ovariectomized-induced bone loss, and inhibits breast tumor-induced osteolysis. This review presents the clinical implications of IL-20, which will lead to a better understanding of the biological functions of IL-20 in these diseases and provide new therapeutic options in the future.

Cardiac aging is initiated by matrix metalloproteinase-9-mediated endothelial dysfunction

Aging is linked to increased matrix metalloproteinase-9 (MMP-9) expression and extracellular matrix turnover, as well as a decline in function of the left ventricle (LV). Previously, we demonstrated that C57BL/6J wild-type (WT) mice > 18 mo of age show impaired diastolic function, which was attenuated by MMP-9 deletion. To evaluate mechanisms that initiate the development of cardiac dysfunction, we compared the LVs of 6-9- and 15-18-mo-old WT and MMP-9 null (Null) mice. All groups showed similar LV function by echocardiography, indicating that dysfunction had not yet developed in the older group. Myocyte nuclei numbers and cross-sectional areas increased in both WT and Null 15-18-mo mice compared with young controls, indicating myocyte hypertrophy. Myocyte hypertrophy leads to an increased oxygen demand, and both WT and Null 15-18-mo mice showed an increase in angiogenic signaling. Plasma proteomic profiling and LV analysis revealed a threefold increase in von Willebrand factor and fivefold increase in vascular endothelial growth factor in WT 15-18-mo mice, which were further elevated in Null mice. In contrast to the upregulation of angiogenic stimulating factors, actual LV vessel numbers increased only in the 15-18-mo Null LV. The 15-18-mo WT showed amplified expression of inflammatory genes related to angiogenesis, including C-C chemokine receptor (CCR)7, CCR10, interleukin (IL)-1f8, IL-13, and IL-20 (all, P < 0.05), and these increases were blunted by MMP-9 deletion (all, P < 0.05). To measure vascular permeability as an index of endothelial function, we injected mice with FITC-labeled dextran. The 15-18-mo WT LV showed increased vascular permeability compared with young WT controls and 15-18-mo Null mice. Combined, our findings revealed that MMP-9 deletion improves angiogenesis, attenuates inflammation, and prevents vascular leakiness in the setting of cardiac aging.

Decreased interleukin-20 level in patients with systemic sclerosis: are they related with angiogenesis?

In this study, we aimed to evaluate the relation between angiogenesis indicators and T helper 17 cytokine group in patients with systemic sclerosis (SSc) which is a disease characterized by impaired angiogenesis and autoimmune response. In our study, patients with SSc are compared with patients with primary Raynaud's phenomenon (RP) and healthy controls. Forty SSc patients, 18 primary RP cases, and 20 healthy controls were included in our study. The demographic and clinical features of patients with SSc were recorded. The serum levels of vascular endothelial growth factor (VEGF), vascular endothelial (VE)-cadherin, interleukin (IL)-20, IL-22, and IL-23 were assessed. In the SSc group, IL-20 level was significantly lower than in both primary RP group and controls (p values <0.001). VE-cadherin level in SSc was significantly higher than in primary RP (p = 0.016). The IL-22 and IL-23 and VEGF levels of SSc, primary RP, and control groups were similar (p values >0.05). In SSc patients, IL-23 correlated negatively with VEGF (r = -0.36, p = 0.025) and positively with VE-cadherin (r = 0.55, p < 0.001). IL-20 levels in SSc patients correlated with disease duration (r = 0.32, p = 0.044). SSc patients with limited involvement had significantly higher VE-cadherin levels than SSc patients with diffuse involvement (p = 0.044). We observed that IL-20 which is an IL-10 group angiogenesis indicator was observed to be suppressed in SSc, suggesting abnormal angiogenesis.

Interleukin-20 promotes migration of bladder cancer cells through extracellular signal-regulated kinase (ERK)-mediated MMP-9 protein expression leading to nuclear factor (NF-κB) activation by inducing the up-regulation of p21(WAF1) protein expression

The role of inflammatory cytokine interleukin-20 (IL-20) has not yet been studied in cancer biology. Here, we demonstrated up-regulation of both IL-20 and IL-20R1 in muscle-invasive bladder cancer patients. The expressions of IL-20 and IL-20R1 were observed in bladder cancer 5637 and T-24 cells. We found that IL-20 significantly increased the expression of matrix metalloproteinase (MMP)-9 via binding activity of NF-κB and AP-1 in bladder cancer cells and stimulated the activation of ERK1/2, JNK, p38 MAPK, and JAK-STAT signaling. Among the pathways examined, only ERK1/2 inhibitor U0126 significantly inhibited IL-20-induced migration and invasion. Moreover, siRNA knockdown of IL-20R1 suppressed migration, invasion, ERK1/2 activation, and NF-κB-mediated MMP-9 expression induced by IL-20. Unexpectedly, the cell cycle inhibitor p21(WAF1) was induced by IL-20 treatment without altering cell cycle progression. Blockade of p21(WAF1) function by siRNA reversed migration, invasion, activation of ERK signaling, MMP-9 expression, and activation of NF-κB in IL-20-treated cells. In addition, IL-20 induced the activation of IκB kinase, the degradation and phosphorylation of IκBα, and NF-κB p65 nuclear translocation, which was regulated by ERK1/2. IL-20 stimulated the recruitment of p65 to the MMP-9 promoter region. Finally, the IL-20-induced migration and invasion of cells was confirmed by IL-20 gene transfection and by addition of anti-IL-20 antibody. This is the first report that p21(WAF1) is involved in ERK1/2-mediated MMP-9 expression via increased binding activity of NF-κB, which resulted in the induction of migration in IL-20/IL-20R1 dyad-induced bladder cancer cells. These unexpected results might provide a critical new target for the treatment of bladder cancer.

Association of the IL-10 gene family locus on chromosome 1 with juvenile idiopathic arthritis (JIA)

Background

The cytokine IL-10 and its family members have been implicated in autoimmune diseases and we have previously reported that genetic variants in IL-10 were associated with a rare group of diseases called juvenile idiopathic arthritis (JIA). The aim of this study was to fine map genetic variants within the IL-10 cytokine family cluster on chromosome 1 using linkage disequilibrium (LD)-tagging single nucleotide polymorphisms (tSNPs) approach with imputation and conditional analysis to test for disease associations.

Methodology/Principal Findings

Fifty-three tSNPs were tested for association between Caucasian paediatric cohorts [219 systemic JIA (sJIA), 187 persistent oligoarticular JIA (pOJIA), and 139 extended OJIA (eOJIA) patients], and controls (Wellcome Trust control cohort, WTCCC2). Significant association with sJIA was detected at rs1400986 in the promoter of IL-20 (odds ratio 1.53; 95% CI 1.21–1.93; p = 0.0004), but in no other subtypes. Imputation analysis identified additional associated SNPs for pOJIA at IL-20 and IL-24, including a rare, functional, missense variant at IL-24 with a p = 0.0002. Penalised logistic regression analysis with HyperLasso and conditional analysis identified several further associations with JIA subtypes. In particular, haplotype analysis refined the sJIA association, with a joint effect at rs1400986 and rs4129024 in intron 1 of MAPKAPK2 (p = 3.2E−5). For pOJIA, a 3-SNP haplotype including rs1878672 in intron 3 of IL-10 showed evidence for association (p = 0.0018). In eOJIA, rs10863962 (3′UTR of FCAMR) and rs12409577 (intron of IL-19) haplotype showed some evidence of association (p = 0.0003).

Conclusions

This study supports previous association of IL-20 with sJIA. Haplotype analyses provided stronger association signals than single point analyses, while a penalised logistic regression approach also suggested multiple independent association signals. Replication studies are required to confirm or refute these findings. The results indicate that combined effects with unknown/rare variants remain to be characterised in JIA, and represent a possible example of synthetic association in this region.

IL-19 and IL-20 genes polymorphisms and haplotype analysis in a vesicoureteral reflux population

Vesicoureteral reflux (VUR) is a common childhood problem, causing renal wounds and escalating the risk of renal deficiency and hypertension. A vast literature exists suggesting that genetic variations play a significant role in the pathogenesis of VUR. The aim of the present study was to estimate whether genetic polymorphisms of IL-19 (GC rs2243158, AT rs2243158) and IL-20 (AG rs2981573, TG rs2981572) genes are involved in the development of VUR.

MATERIALS AND METHODS

The tetra amplification mutation refractory system-polymerase chain reaction (Tetra-ARMS PCR) was applied for analyzing four polymorphic sites of IL-19 (GC rs2243158, AT rs2243158) and IL-20 (AG rs2981573, TG rs2981572) genes in 110 healthy controls and 124 VUR children.

RESULTS

A significant association was found between the combined genotypes of IL19GC+CC and IL20TG+GG and increased risk of VUR (OR = 1.90, 95% CL, 1.06-3.41; OR=1.87, 95% CL, 1.06-3.29, respectively). The frequency of allele G in both sites of IL-20 (IL20AG rs2981573 and IL20TG, rs2981572) showed a statistically significant difference (p = 0.01) between cases and controls in comparison with the wild type. The combined haplotype analysis of IL-19 and IL-20 polymorphic sites revealed that HT2, HT3 and HT5 haplotypes marginally increased the risk of VUR, but not statistically significantly. Gene-gene interaction data of IL-19 (GC rs2243158, AT rs2243158) and IL-20 (AG rs2981573, TG rs2981572) in various genotype patterns highlighted the fact that most of the genotype combinations increased the risk of disease insignificantly.

CONCLUSION

This is the first evidence regarding IL-19 and IL-20 cytokine genes polymorphism and risk of VUR, suggesting the need for further study with large sample size and in different populations to confirm the presented data.

Expression of IL-20 in synovium and lesional skin of patients with psoriatic arthritis: differential response to alefacept treatment

Introduction

Psoriatic arthritis (PsA) is an inflammatory joint disease associated with psoriasis. Alefacept (a lymphocyte function-associated antigen (LFA)-3 Ig fusion protein that binds to CD2 and functions as an antagonist to T-cell activation) has been shown to result in improvement in psoriasis but has limited effectiveness in PsA. Interleukin-20 (IL-20) is a key proinflammatory cytokine involved in the pathogenesis of psoriasis. The effects of alefacept treatment on IL-20 expression in the synovium of patients with psoriasis and PsA are currently unknown.

Methods

Eleven patients with active PsA and chronic plaque psoriasis were treated with alefacept (7.5 mg per week for 12 weeks) in an open-label study. Skin biopsies were taken before and after 1 and 6 weeks, whereas synovial biopsies were obtained before and 4 and 12 weeks after treatment. Synovial biopsies from patients with rheumatoid arthritis (RA) (n = 10) were used as disease controls. Immunohistochemical analysis was performed to detect IL-20 expression, and stained synovial tissue sections were evaluated with digital image analysis. Double staining was performed with IL-20 and CD68 (macrophages), and conversely with CD55 (fibroblast-like synoviocytes, FLSs) to determine the phenotype of IL-20-positive cells in PsA synovium. IL-20 expression in skin sections (n = 6) was analyzed semiquantitatively.

Results

IL-20 was abundantly expressed in both PsA and RA synovial tissues. In inflamed PsA synovium, CD68⁺ macrophages and CD55⁺ FLSs coexpressed IL-20, and its expression correlated with the numbers of FLSs. IL-20 expression in lesional skin of PsA patients decreased significantly (P = 0.04) 6 weeks after treatment and correlated positively with the Psoriasis Area and Severity Index (PASI). IL-20 expression in PsA synovium was not affected by alefacept.

Conclusions

Conceivably, the relatively limited effectiveness of alefacept in PsA patients (compared with anti-tumor necrosis factor (TNF) therapy) might be explained in part by persistent FLS-derived IL-20 expression.

Anti-IL-20 monoclonal antibody alleviates inflammation in oral cancer and suppresses tumor growth

Interleukin-20 (IL-20) is a proinflammatory cytokine involved in rheumatoid arthritis, atherosclerosis, and osteoporosis. However, little is known about the role of IL-20 in oral cancer. We explored the function of IL-20 in the tumor progression of oral cancer. IL-20 expression levels in tumorous and nontumorous oral tissue specimens from 40 patients with four different stages oral cancer were analyzed with immunohistochemistry (IHC) staining and quantitative real-time PCR (qRT-PCR). Expression of IL-20 and its receptor subunits was higher in clinical oral tumor tissue than in nontumorous oral tissue. The role of IL-20 was examined in two oral cancer cell lines (OC-3 and OEC-M1). In vitro, IL-20 promoted TNF-α, IL-1β, MCP-1, CCR4, and CXCR4 and increased proliferation, migration, reactive oxygen species (ROS) production, and colony formation of oral cancer cells via activated STAT3 and AKT/JNK/ERK signals. To evaluate the therapeutic potential of anti-IL-20 monoclonal antibody 7E for treating oral cancer, an ex vivo tumor growth model was used. In vivo, 7E reduced tumor growth and inflammation in oral cancer cells. In conclusion, IL-20 promoted oral tumor growth, migration, and tumor-associated inflammation. Therefore, IL-20 may be a novel target for treating oral cancer, and anti-IL-20 monoclonal antibody 7E may be a feasible therapeutic.

Identification of pro-inflammatory cytokines associated with muscle invasive bladder cancer; the roles of IL-5, IL-20, and IL-28A

We used gene expression profiling to identify inflammatory cytokines that correlate with bladder cancer development. Gene expression profiles of the tissue samples were investigated using cDNA microarrays that contained 103 non-muscle invasive bladder cancers (NMIBC), 62 muscle invasive bladder cancers (MIBC), 58 samples of histologically normal-looking surrounding tissues, and 10 normal, healthy subjects who served as the control cohort for comparison. We grouped the data-sets according to biological characterizations and focused on immune response genes with at least 2-fold differential expression in MIBC vs. controls. The experimental data-set identified 36 immune-related genes that were significantly altered in MIBC samples. In addition, 10 genes were up-regulated and 26 genes were down-regulated in MIBC samples compared with the normal tissues. Among the 10 up-regulated molecules examined, the capacity for both wound-healing migration and invasion was enhanced in response to IL-5, IL-20, and IL-28A in bladder cancer cell lines (253J and EJ cells), compared with untreated cells. The expression levels of IL-5, IL-20, and IL-28A were increased in patients with MIBC. All 3 cytokines and their receptors were produced in bladder cancer cell lines, as determined by real-time PCR, immunoblot analysis and confocal immunofluorescence. Up-regulation of MMP-2 and MMP-9 was found after IL-5, IL-20, and IL-28A stimulation in both cell types. Moreover, an EMSA assay showed that treatment with IL-5, IL-20, and IL-28A induced activation of the transcription factors NF-κB and AP-1 that regulate the MMP-9 promoter. Finally, activation of MAPK and Jak-Stat signaling was observed after the addition of IL-5, IL-20, and IL-28A to bladder cancer cells. This study suggests the presence of specific inflammatory cytokine (IL-5, IL-20, and IL-28A)-mediated association in bladder cancer development. All 3 cytokines may be important new molecular targets for the modulation of migration and invasion in bladder cancer.

The cutaneous vascular system in chronic skin inflammation

The blood and lymphatic vasculature have an important role in skin homeostasis. Angiogenesis and lymphangiogenesis-the growth of new vessels from existing ones-have received tremendous interest because of their role in promoting cancer spread. However, there is increasing evidence that both vessel types also have a major role in acute and chronic inflammatory disorders. Vessels change their phenotype during inflammation (vascular remodeling). In inflamed skin, vascular remodeling consists of a hyperpermeable, enlarged network of vessels with increased blood flow, and influx of inflammatory cells. During chronic inflammation, the activated endothelium expresses adhesion molecules, cytokines, and other molecules that lead to leukocyte rolling, attachment, and migration into the skin. Recent studies reveal that inhibition of blood vessel activation exerts potent anti-inflammatory properties. Thus, anti-angiogenic drugs might be used to treat inflammatory conditions. In particular, topical application of anti-angiogenic drugs might be ideally suited to circumvent the adverse effects of systemic therapy with angiogenesis inhibitors. Our recent results indicate that stimulation of lymphatic vessel growth and function unexpectedly represents a new approach for treating chronic inflammatory disorders.

Uterine gene expression in the live-bearing lizard, Chalcides ocellatus, reveals convergence of squamate reptile and mammalian pregnancy mechanisms

Although the morphological and physiological changes involved in pregnancy in live-bearing reptiles are well studied, the genetic mechanisms that underlie these changes are not known. We used the viviparous African Ocellated Skink, Chalcides ocellatus, as a model to identify a near complete gene expression profile associated with pregnancy using RNA-Seq analyses of uterine transcriptomes. Pregnancy in C. ocellatus is associated with upregulation of uterine genes involved with metabolism, cell proliferation and death, and cellular transport. Moreover, there are clear parallels between the genetic processes associated with pregnancy in mammals and Chalcides in expression of genes related to tissue remodeling, angiogenesis, immune system regulation, and nutrient provisioning to the embryo. In particular, the pregnant uterine transcriptome is dominated by expression of proteolytic enzymes that we speculate are involved both with remodeling the chorioallantoic placenta and histotrophy in the omphaloplacenta. Elements of the maternal innate immune system are downregulated in the pregnant uterus, indicating a potential mechanism to avoid rejection of the embryo. We found a downregulation of major histocompatability complex loci and estrogen and progesterone receptors in the pregnant uterus. This pattern is similar to mammals but cannot be explained by the mammalian model. The latter finding provides evidence that pregnancy is controlled by different endocrinological mechanisms in mammals and reptiles. Finally, 88% of the identified genes are expressed in both the pregnant and the nonpregnant uterus, and thus, morphological and physiological changes associated with C. ocellatus pregnancy are likely a result of regulation of genes continually expressed in the uterus rather than the initiation of expression of unique genes.

Anti-IL-20 monoclonal antibody suppresses breast cancer progression and bone osteolysis in murine models

IL-20 is a proinflammatory cytokine involved in rheumatoid arthritis, atherosclerosis, and stroke. However, little is known about its role in breast cancer. We explored the function of IL-20 in tumor growth and metastasis, as well as in clinical outcome. Tumor expression of IL-20 was assessed by immunohistochemical staining among 198 patients with invasive ductal carcinoma of the breast, using available clinical and survival data. IL-20 expression was associated with advanced tumor stage, greater tumor metastasis, and worse survival. Reverse transcription quantitative polymerase chain reaction showed that clinical breast tumor tissue expressed higher levels of IL-20 and its receptors than did nontumorous breast tissue. IL-20 was also highly expressed in breast cancer bone-metastasis tissue. In vitro, IL-20 upregulated matrix metalloproteinase-9, matrix metalloproteinase-12, cathepsin K, and cathepsin G, and enhanced proliferation and migration of breast cancer cells, which were inhibited by anti-IL-20 mAb 7E. In vivo, we generated murine models to evaluate the therapeutic potential of 7E, using luminescence intensity, radiological scans, and micro-computed tomography. 7E reduced tumor growth, suppressed bone colonization, diminished tumor-mediated osteolysis, and lessened bone density decrement in mice injected with breast cancer cells. In conclusion, our results suggest that IL-20 plays pivotal roles in the tumor progression of breast cancer. IL-20 expression in breast cancer tissue is associated with a poor clinical outcome. Anti-IL-20 mAb 7E suppressed bone colonization and decreased osteolytic bone lesions. Therefore, IL-20 may be a novel target in treating breast tumor-induced osteolysis.

Purification, crystallization and preliminary X-ray diffraction analysis of the IL-20-IL-20R1-IL-20R2 complex

Interleukin-20 (IL-20) is an IL-10-family cytokine that regulates innate and adaptive immunity in skin and other tissues. In addition to protecting the host from various external pathogens, dysregulated IL-20 signaling has been shown to contribute to the pathogenesis of human psoriasis. IL-20 signals through two cell-surface receptor heterodimers, IL-20R1-IL-20R2 and IL-22R1-IL-20R2. In this report, crystals of the IL-20-IL-20R1-IL-20R2 ternary complex have been grown from polyethylene glycol solutions. The crystals belonged to space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = 111, c = 135 Å, and diffracted X-rays to 3 Å resolution. The crystallographic asymmetric unit contains one IL-20-IL-20R1-IL-20R2 complex, corresponding to a solvent content of approximately 54%.