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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.

The role of immune mediators, including proinflammatory cytokines in chemotherapy-induced peripheral neuropathy (CIPN), remains unclear. Here, we studied the contribution of interleukin-20 (IL-20) to the development of paclitaxel-induced peripheral neuropathy. Increased serum levels of IL-20 in cancer patients with chemotherapy were accompanied by increased CIPN risk. In mouse models, proinflammatory IL-20 levels in serum and dorsal root ganglia fluctuated with paclitaxel treatment. Blocking IL-20 with the neutralizing antibody or genetic deletion of its receptors prevented CIPN, alleviated peripheral nerve damage, and dampened inflammatory responses, including macrophage infiltration and cytokine release. Mechanistically, paclitaxel upregulated IL-20 through dysregulated Ca homeostasis, which augmented chemotherapy-induced neurotoxicity. Importantly, IL-20 suppression did not alter paclitaxel efficacy on cancer treatment both in vitro and in vivo. Together, targeting IL-20 ameliorates paclitaxel-induced peripheral neuropathy by suppressing neuroinflammation and restoring Ca homeostasis. Therefore, the anti-IL-20 monoclonal antibody is a promising therapeutic for the prevention and treatment of paclitaxel-induced neuropathy.

Background Dry eye disease (DED) is a common disease in ophthalmology, affecting millions of people worldwide. Recent studies have shown that inflammation is the core mechanism of DED. IL-20 is a proinflammatory cytokine involved in various inflammatory diseases. Therefore, we aimed to explore the role of this cytokine in the pathogenesis of DED and evaluate the therapeutic potential of the anti-IL-20 monoclonal antibody (mAb) 7E for DED treatment. Methods Clinical tear samples from patients with DED and non-DED controls were collected and their IL-20 protein levels were determined. We established three DED animal models to explore the role of IL-20 and the efficacy of IL-20 antibody in DED. Benzalkonium chloride (BAC)-induced over-evaporative DED, extra-orbital lacrimal gland excision (LGE)-induced aqueous tear-deficient DED, and desiccating stress (DS)-induced combined over-evaporative and aqueous tear-deficient DED animal models were established to investigate the role of IL-20. The anti-IL-20 antibody 7E was established to neutralize IL-20 activity. The effects of IL-20 or 7E on human corneal epithelial cells and macrophages under hyperosmotic stress were analyzed. 7E was topically applied to eyes to evaluate the therapeutic effects in the DED animal models. Results IL-20 was significantly upregulated in the tears of patients with DED and in the tears and corneas of DED animal models. Under hyperosmotic stress, IL-20 expression was induced via NFAT5 activation in corneal epithelial cells. 7E suppressed hyperosmotic stress-induced activation of macrophages. IL-20 induced cell death in corneal epithelial cells and 7E protected cells from hyperosmotic stress-induced cell death. Blocking IL-20 signaling with 7E protected mice from BAC-induced, LGE-induced, and DS-induced DED by reducing DED symptoms and inhibiting inflammatory responses, macrophage infiltration, apoptosis, and Th17 populations in the conjunctiva and draining lymph nodes. Conclusions Our results demonstrated the functions of IL-20 in DED and presented a potential therapeutic option for this condition. Graphical Abstract

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.

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 analyzed 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.

In this study, we establish a population-based human induced pluripotent stem cell (hiPSC) drug screening platform for toxicity assessment. After recruiting 1,000 healthy donors and screening for high-frequency human leukocyte antigen (HLA) haplotypes, we identify 13 HLA-homozygous "super donors" to represent the population. These "super donors" are also expected to represent at least 477,611,135 of the global population. By differentiating these representative hiPSCs into cardiomyocytes and neurons we show their utility in a high-throughput toxicity screen. To validate hit compounds, we demonstrate dose-dependent toxicity of the hit compounds and assess functional modulation. We also show reproducible in vivo drug toxicity results using mouse models with select hit compounds. This study shows the feasibility of using a population-based hiPSC drug screening platform to assess cytotoxicity, which can be used as an innovative tool to study inter-population differences in drug toxicity and adverse drug reactions in drug discovery applications.

Background Interleukin-24 (IL-24) binds to two kinds of receptor complexes, namely IL-20R1/IL-20R2 and IL-20R2/IL-22R1, which are also bound by IL-20. IL-20 plays a detrimental role in liver fibrosis. Due to the sharing of receptor complexes, we aimed to determine whether IL-24 also participates in liver fibrosis. Methods Clinical biopsy specimens from various stages of liver fibrosis were used to analyze IL-24 expression. IL-24 protein was administered to mice with thioacetamide (TAA)-induced liver injury. The direct effects of IL-24 on mouse primary hepatocytes or hepatic stellate cells (HSCs) were analyzed. Wild-type, IL-20R1-, and IL20R2-deficient mice were used to establish a model of acute TAA-induced liver injury. Findings Among patients with more severe liver fibrosis, there was a reduced IL-24/IL-20 ratio. Administration of IL-24 protein protected mice from TAA-induced liver injury and reduction of liver inflammation by antioxidant effects. IL-24 protected hepatocytes from TAA-induced apoptosis and prevented liver fibrosis through the inhibition of the HSCs activation. The protective role of IL-24 acted on liver cells were mainly IL-20R1-independent. IL-20R2-deficient mice exhibited more severe liver injury upon TAA treatment, thus confirming the protective role of IL-24. Interpretation IL-24 plays a key protective role in the progression of liver injury and has therapeutic potential for treating liver injuries. Funding This work was supported by the Ministry of Science and Technology of Taiwan (MOST 106–2320-B-006–024) and Taiwan Liver Disease Prevention & Treatment Research Foundation.

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.

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 p21WAF1 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.

In this paper, we report our study on using a piezoelectric membrane to measure the contraction profile of Human iPSC cardiomyocytes. To guide HiPSC cardiomyocytes aligned concentrically with respect to the circular-shape piezoelectric membrane, 20 μm polydimethylsiloxane micro-grooves with 20 μm separation are molded on top of the piezoelectric membrane to form multiple concentric rings. Gelatin or fibronectin is coated on the microgrooves for promoting cell adhesions. Using this method, repeated contractions can be measured by using the circular piezoelectric membrane, and the contraction profile can be monitored. To study the performance of the piezoelectric membrane, different dosage of commercial drugs are used, including Isoproterenol and Metoprolol. Experimental results demonstrated that the piezoelectric membrane can measure the contraction profile of cardiomyocytes. Cellular responses to different drugs and dosage can be monitored electrically.

In this paper, we report on using mass transport to control nutrition supply of colorectal cancer cells for developing a microtumor in a confined microchamber. To mimic the spatial heterogeneity of a tumor, two microfluidic configurations based on resistive circuits are designed. One has a convection-dominated microchamber to simulate the tumor region proximal to leaky blood vessels. The other has a diffusion-dominated microchamber to mimic the tumor core that lacks blood vessels and nutrient supply. Thus, the time for nutrition to fill the microchamber can vary from tens of minutes to several hours. Results show that cells cultured under a diffusive supply of nutrition have a high glycolytic rate and a nearly constant oxygen consumption rate. In contrast, cells cultured under convective supply of nutrition have a gradual increase of oxygen consumption rate with a low glycolytic rate. This suggests that cancer cells have distinct reactions under different mass transport and nutrition supply. Using these two microfluidic platforms to create different rate of nutrition supply, it is found that a continuous microtumor that almost fills the mm-size microchamber can be developed under a low-nutrient supply environment, but not for the convective condition. It also is demonstrated that microchannels can simulate the delivery of anti-cancer drugs to the microtumor under controlled mass-transport. This method provides a means to develop a larger scale microtumor in a lab-on-a-Chip system for post development and stimulations, and microchannels can be applied to control the physical and chemical environment for anti-cancer drug screening.

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.

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 is a crucial mediator for regulating tubular cell apoptosis, promoting renal fibrosis, and enhancing podocyte dysfunction.

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive destruction of articular cartilage. Interleukin (IL)-20 is a proinflammatory cytokine involved in the pathogenesis of rheumatoid arthritis. We investigated the role of IL-20 in OA and evaluated whether anti-IL-20 antibody (7E) treatment attenuates disease severity in murine models of surgery-induced OA. Immunohistochemical staining was used to detect IL-20 and its receptors expression in synovial tissue and cartilage from OA patients, and in OA synovial fibroblasts (OASFs) and chondrocytes (OACCs) from rodents with surgery-induced OA. RTQ-PCR and western blotting were used to determine IL-20-regulated OA-associated gene expression in OASFs and OACCs. OA rats and OA mice were treated with 7E. Arthritis severity was determined based on the degree of cartilage damage and the arthritis severity score. We found that IL-20 and its receptors were expressed in OASFs and OACCs. IL-20 induced TNF-α, IL-1β, MMP-1, and MMP-13 expression by activating ERK-1/2 and JNK signals in OASFs. IL-20 not only upregulated MCP-1, IL-6, MMP-1, and MMP-13 expression, but also downregulated aggrecan, type 2 collagen, TGF-β, and BMP-2 expression in OACCs. Arthritis severity was significantly lower in 7E-treated OA rats, and 7E- or MSC-treated OA mice. Therefore, we concluded that IL-20 was involved in the progression and development of OA through inducing proinflammatory cytokines and OA-associated gene expression in OASFs and OACCs. 7E reduced the severity of arthritis in murine models of surgery-induced OA. Our findings provide evidence that IL-20 is a novel target and that 7E is a potential therapeutic agent for OA.

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. Mol Cancer Res; 10(11); 1430–9. ©2012 AACR.

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.

IL-20 promotes osteoclast differentiation by inducing RANK and RANKL expression in osteoclast precursors and osteoblasts, respectively., IL-20 is a proinflammatory cytokine of the IL-10 family that is involved in psoriasis, rheumatoid arthritis, atherosclerosis, and stroke. However, little is known about the role of IL-20 in bone destruction. We explored the function of IL-20 in osteoclastogenesis and the therapeutic potential of anti–IL-20 monoclonal antibody 7E for treating osteoporosis. Higher serum IL-20 levels were detected in patients with osteopenia and osteoporosis and in ovariectomized (OVX) mice. IL-20 mediates osteoclastogenesis by up-regulating the receptor activator of NF-κB (RANK) expression in osteoclast precursor cells and RANK ligand (RANKL) in osteoblasts. 7E treatment completely inhibited osteoclast differentiation induced by macrophage colony-stimulating factor (M-CSF) and RANKL in vitro and protected mice from OVX-induced bone loss in vivo. Furthermore, IL-20R1–deficient mice had significantly higher bone mineral density (BMD) than did wild-type controls. IL-20R1 deficiency also abolished IL-20–induced osteoclastogenesis and increased BMD in OVX mice. We have identified a pivotal role of IL-20 in osteoclast differentiation, and we conclude that anti–IL-20 monoclonal antibody is a potential therapeutic for protecting against osteoporotic bone loss.

The influence of interleukin (IL)-19, a recently discovered cytokine in the IL-10 family, on tissue is still unclear. Our aim was to determine the distribution of IL-19 expression and to delineate the cell types that express IL-19 in healthy and neoplastic tissue, because this information will significantly facilitate the exploration of its pathophysiological functions. We used tissue microarray technology and an immunohistochemical survey with an anti-IL-19 monoclonal antibody to examine the expression of IL-19 in 28 healthy and 15 neoplastic tissues. IL-19 protein was positively stained in 15 healthy tissue types and three major cell types: epithelial cells, endothelial cells, and macrophages. We also found that several types of tumor cells were positively stained for IL-19, especially in squamous cell carcinoma (SCC) of the skin, tongue, esophagus, and lung. SCC of the oral cavity expressed IL-19 mRNA and its receptors. In two cell lines derived from SCC of oral cavity tumor tissue, IL-19 specifically activated an intracellular signal and induced proliferation of the cells, which indicated that IL-19 may act in an autocrine manner in SCC tumors. This study provides important references for further investigation of the biological functions and clinical implications of IL-19 in humans.

Interleukin (IL)-10 is an anti-inflammatory factor that suppresses renal fibrosis and improves renal function in CKD rats. IL-20 belongs to the IL-10 family; therefore, we sought to determine whether IL-20 is involved in CKD. CKD patients at stage five expressed significantly higher IL-20 in serum than controls. Immunohistochemical staining demonstrated that more IL-20 protein was expressed in the kidney tubular-epithelial cells, mesangial cells, and immune cells of CKD rats with a 5/6 nephrectomy. The lung, liver, and heart tissue of CKD rats also overexpressed IL-20. Thus, we treated two tubular epithelial cells, TKPTS and M-1 cells, with IL-20 to study its effects on CKD. IL-20 treatment induced apoptosis in these cells via caspase-3 activation. Incubating IL-20 with rat interstitial fibroblasts, NRK-49F cells, upregulated TGF-beta1 production, one key inducer for renal fibrogenesis. Therefore, IL-20 injured renal epithelial cells and induced fibroblasts to produce TGF-beta1 that hastened the progression of CKD.

Acute renal failure is an abrupt decrease in renal function. Interleukin (IL)-10 inhibits ischemic and cisplatin-induced acute renal failure. We aimed to determine whether IL-20 affects renal tubular epithelial cells and is associated with acute renal failure. We analyzed the expression of IL-20 and its receptor (R) in the kidneys of rats with HgCl(2)-induced acute renal failure. Reverse transcription-PCR showed upregulated IL-20, and its receptors and immunohistochemical staining showed strongly expressed IL-20 protein in proximal tubular epithelial cells. We analyzed human proximal tubular epithelial (HK-2) cells, which expressed both IL-20 and its receptors. IL-20 specifically induced mitochondria-dependent apoptosis by activating caspase 9 in HK-2 cells. IL-20 also activated c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2, the downstream signals implicated in the apoptosis of HK-2 cells. Furthermore, IL-20 upregulated the transcripts of transforming growth factor (TGF)-beta1, a critical mediator of renal injury. In hypoxic HK-2 cells, IL-20 and IL-22R1 transcripts increased, and IL-20 upregulated IL-1 beta transcripts. In vivo study further demonstrated that anti-IL-20 antibody reduced the expression of TGF-beta1 and IL-1 beta and the number of damaged tubular cells in the kidneys of rats with acute renal failure. We concluded that IL-20 may be involved in the injury of renal epithelial cells in acute renal failure.

Rheumatoid arthritis, a systemic autoimmune disease, causes chronic joint inflammation and bone destruction. Interleukin (IL)-20's association with this disease, and its expression and regulation has been extensively studied since 2006. Anti-IL-20 antibody has paved the way to clinical trials aimed at blocking the pathogenic actions of IL-20 in rheumatoid arthritis. This review focuses on current knowledge of IL-20's involvement in the pathogenesis of rheumatoid arthritis.

Interleukin (IL)-19 belongs to the IL-10 family which includes IL-19, IL-20, IL-22, AK155, and MDA-7. IL-10 is a potent immunomodulatory cytokine with implications for pathogenesis in various autoimmune diseases. Polymorphism of the IL-10 promoter region correlates with disease outcome. To understand the gene regulation of IL-19, we analyzed the IL-19 promoter region. A regulatory region (PE), 148 bp upstream of exon 1 of IL-19 and linked to a luciferase reporter gene, supported luciferase activity 13 times greater than that supported by a negative promoterless control. An electrophoretic mobility shift assay (EMSA) showed specific binding sites for the transcription factors of the oligonucleotides PE1 (−148 to −98) derived from PE. We identified the sequence TGTGGT (−142 to −138) on PE1 as the binding site for the transcription factor AML1, and crucial for the promoter activity of IL-19 because substituting 1 bp in the PE region (−139G → T) abolished IL-19 promoter activity.

IL-20 belongs to the IL-10 family and plays a role in skin inflammation and the development of hematopoietic cells. Little is known about its other biological functions and clinical implications, however. Updated information about IL-20, such as its identification, expression, receptors, signaling, biological activities, and potential clinical implications, is illustrated in this review based on our research and on data available in the literature. Our studies of IL-20 show that it is a pleiotropic cytokine with potent inflammatory, angiogenic, and chemoattractive characteristics. Inflammation and angiogenesis are essential for the pathogenesis of rheumatoid arthritis and atherosclerosis. Based on in vitro data and clinical samples, we demonstrated that IL-20 is involved in the diseases of rheumatoid arthritis and atherosclerosis. In addition, we found in our studies that IL-20 signaled through different molecules in several cells. The present review presents the clinical implications of IL-20 in rheumatoid arthritis and atherosclerosis. It may provide new therapeutic options in the future.

Interleukin (IL)-20 is a proinflammatory cytokine in the IL–10 family. IL–20 is associated with tumor promotion in the pathogenesis of oral, bladder, and breast cancer. However, little is known about the role of IL–20 in prostate cancer. We hypothesize that IL–20 promotes the growth of prostate cancer cells. Immunohistochemical staining showed that IL–20 and its receptors were expressed in human PC–3 and LNCaP prostate cancer cell lines and in prostate tumor tissue from 40 patients. In vitro, IL–20 upregulated N-cadherin, STAT3, vimentin, fibronectin, RANKL, cathepsin G, and cathepsin K, and increased the migration and colony formation of prostate cancer cells via activated p38, ERK1/2, AKT, and NF-κB signals in PC–3 cells. We investigated the effects of anti-IL–20 monoclonal antibody 7E on prostate tumor growth in vivo using SCID mouse subcutaneous and intratibial xenograft tumor models. In vivo, 7E reduced tumor growth, suppressed tumor-mediated osteolysis, and protected bone mineral density after intratibial injection of prostate cancer cells. We conclude that IL–20 is involved in the cell migration, colony formation, and tumor-induced osteolysis of prostate cancer. Therefore, IL–20 might be a novel target for treating prostate cancer.

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. Serious kidney damage often found in type 1 and type 2 diabetes has been linked to the natural signaling molecule interleukin-20 (IL-20). Ming-Shi Chang and colleagues at the National Cheng Kung University in Taiwan found increased levels of both IL-20 and its receptor molecule in mice and rats with chemically induced diabetes. They also found that IL-20 induced changes in gene activity, leading to cell death in cultured specialized kidney cells known as podocytes. Patients with diabetes were also shown to have increased IL-20 levels. Treating diabetic mice with an antibody that bound to and interfered with the activity of IL-20 improved kidney function and reduced biochemical indicators of diabetes. Understanding the mechanism of IL-20 involvement in this common complication of diabetes could help devise treatments to prevent or limit the damage.

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.

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

Replicating in vitro the complex in vivo tissue microenvironment has the potential to transform our approach to medicine and also our understanding of biology. In order to accurately model the 3D arrangement and interaction of cells and extracellular matrix, new microphysiological systems must include a vascular supply. The vasculature not only provides the necessary convective transport of oxygen, nutrients, and waste in 3D culture, but also couples and integrates the responses of organ systems. Here we combine tissue engineering and microfluidic technology to create an in vitro 3D metabolically active stroma (∼1 mm(3)) that, for the first time, contains a perfused, living, dynamic, interconnected human capillary network. The range of flow rate (μm/s) and shear rate (s(-1)) within the network was 0-4000 and 0-1000, respectively, and thus included the normal physiological range. Infusion of FITC dextran demonstrated microvessels (15-50 μm) to be largely impermeable to 70 kDa. Our high-throughput biology-directed platform has the potential to impact a broad range of fields that intersect with the microcirculation, including tumor metastasis, drug discovery, vascular disease, and environmental chemical toxicity.

Inflammation and renal tubular injury are major features of acute kidney injury (AKI). Many cytokines and chemokines are released from injured tubular cells and acts as proinflammatory mediators. However, the role of IL-19 in the pathogenesis of AKI is not defined yet. In bilateral renal ischemia/reperfusion injury (IRI)-induced and HgCl2-induced AKI animal models, real-time quantitative (RTQ)-PCR showed that the kidneys, livers, and lungs of AKI mice expressed significantly higher IL-19 and its receptors than did sham control mice. Immunohistochemical staining showed that IL-19 and its receptors were strongly stained in the kidney, liver, and lung tissue of AKI mice. In vitro, IL-19 upregulated MCP-1, TGF-β1, and IL-19, and induced mitochondria-dependent apoptosis in murine renal tubular epithelial M-1 cells. IL-19 upregulated TNF-α and IL-10 in cultured HepG2 cells, and it increased IL-1β and TNF-α expression in cultured A549 cells. In vivo, after renal IRI or a nephrotoxic dose of HgCl2 treatment, IL-20R1-deficient mice (the deficiency blocks IL-19 signaling) showed lower levels of blood urea nitrogen (BUN) in serum and less tubular damage than did wild-type mice. Therefore, we conclude that IL-19 mediates kidney, liver, and lung tissue damage in murine AKI and that blocking IL-19 signaling may provide a potent therapeutic strategy for treating AKI.

We report the first demonstration of a microfluidic platform that captures the full physiological range of mass transport in 3-D tissue culture. The basis of our method used long microfluidic channels connected to both sides of a central microtissue chamber at different downstream positions to control the mass transport distribution within the chamber. Precise control of the Peclet number (Pe), defined as the ratio of convective to diffusive transport, over nearly five orders of magnitude (0.0056 to 160) was achieved. The platform was used to systematically investigate the role of physiological mass transport on vasculogenesis. We demonstrate, for the first time, that vasculogenesis can be independently stimulated by interstitial flow (Pe > 10) or hypoxic conditions (Pe < 0.1), and not by the intermediate state (normal living tissue). This simple platform can be applied to physiological and biological studies of 3D living tissue followed by pathological disease studies, such as cancer research and drug screening.

Purpose: Interleukin (IL)-19 was expressed in invasive ductal carcinoma (IDC) of the breast tissue but not in healthy breast tissue. We explored the effects of IL-19 on the pathogenesis of breast cancer and its clinical outcome. Experimental Design: Tumor expression of IL-19 was assessed by immunohistochemistry and/or real-time quantitative PCR between two groups of patients with breast IDC (n = 60 and 143, respectively) with available clinical and survival data. We examined the effects of IL-19 on cytokine and chemokine production as well as proliferation and migration in breast cancer cells. Mice were injected with IL-19–overexpressing or vector control 67NR cells and the tumor growth and lung metastatic micronodules were measured. Results: Of the IDC specimens, high IL-19 expression was associated with advanced tumor stage, high tumor metastasis, and worse survival. In vitro, IL-19 induced transcripts of IL-1β, IL-6, TGF-β, matrix metalloproteinase (MMP)2, MMP9, and CXCR4 in 4T1 breast cancer cells; induced fibronectin expression and assembly; and promoted cancer cell proliferation and migration, which were inhibited by anti-IL-19 monoclonal antibody (mAb). Endogenous fibronectin expression and cancer cell migration were lower in IL-19 knockdown 4T1 cells. In 4T1 cells, hypoxia induced IL-19 and CXCR4 expression, which was inhibited by anti-IL-19 mAb. IL-19 overexpression in noninvasive 67NR cancer cells increased cell proliferation and migration. In vivo, mice injected with IL-19–overexpressing 67NR cell clones showed larger tumors and more metastatic micronodules in the lung. Conclusions: High IL-19 expression in breast cancer tissue is associated with a poor clinical outcome. IL-19 is pivotal in the pathogenesis of breast cancer. Clin Cancer Res; 18(3); 713–25. ©2011 AACR.

Ground glass hepatocytes (GGH) in chronic hepatitis B virus (HBV) infection harbor HBV pre-S deletion mutants in endoplasmic reticulum (ER) and exhibit complex biologic features such as ER stress, DNA damage, and growth advantage. The presence of pre-S mutants in serum has been shown to predict the development of hepatocellular carcinoma (HCC) in HBV carriers. GGHs hence represent a potentially preneoplastic lesion. Whether a specific growth factor is overexpressed and activated in GGHs remains to be clarified. In this study, growth factor(s) up-regulated by pre-S mutants was identified using a growth factor array in HuH-7 cells. Immunohistochemistry, reverse-transcriptase polymerase chain reaction, and Western blot analysis were performed to study the participation of these genes and their signal pathways in HuH-7 cells and liver tissues. We demonstrate that vascular endothelial growth factor-A (VEGF-A) was up-regulated by pre-S mutants in HuH-7 cells and further confirmed in GGHs by immunostaining. The VEGF-A up-regulation by pre-S mutants could be suppressed by vomitoxin, an ER stress inhibitor. Furthermore, pre-S mutants-expressed HuH-7 cells exhibited activation of Akt/mTOR (mammalian target of rapamycin) signaling and increased growth advantage, which could be inhibited by VEGF-A neutralization. Consistent with this notion, enhanced expression of VEGF-A and activation of Akt/mTOR signaling, comparable to the levels of paired HCC tissues, were also detected in HBV-related nontumorous livers. Conclusion: The enhanced expression of VEGF-A in GGHs provides potential mechanism to explain the progression from preneoplastic GGHs to HCC in chronic HBV infection. (HEPATOLOGY 2009;49:1962–1971.)