Induced interleukin-19 contributes to cell-mediated immunosuppression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass

T cells and their products in diabetic kidney disease

Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease and has gradually become a public health problem worldwide. DKD is increasingly recognized as a comprehensive inflammatory disease that is largely regulated by T cells. Given the pivotal role of T cells and T cells-producing cytokines in DKD, we summarized recent advances concerning T cells in the progression of type 2 diabetic nephropathy and provided a novel perspective of immune-related factors in diabetes. Specific emphasis is placed on the classification of T cells, process of T cell recruitment, function of T cells in the development of diabetic kidney damage, and potential treatments and therapeutic strategies involving T cells.

The role and transformative potential of IL-19 in atherosclerosis

Atherosclerotic cardiovascular disease is the leading cause of death worldwide. Traditionally, IL-19 was thought to be expressed in only immune cells, but studies revealed that IL-19 is also expressed in multiple atherosclerotic plaque cell types, but not normal arteries, in humans and mice. IL-19 reduces the development of atherosclerosis via multiple mechanisms, including balancing cholesterol metabolism; enhancing Th2 immune cell polarization; reducing the inflammatory response; and reducing the proliferation, migration and chemotaxis of vascular smooth muscle cells (VSMCs). Clinical and/or animal studies have primarily aimed to achieve regression and/or stabilization of atherosclerotic plaques, with regression in particular indicating a very good drug response. Most antiatherosclerotic drugs in current clinical use, including atorvastatin and alirocumab, target hyperlipidemia. Several other drugs have also been investigated in clinical trials as anti-inflammatory agents; the development of some of these agents has been terminated (canakinumab, darapladib, varespladib, losmapimod, atreleuton, setileuton, PF-04191834, veliflapon, and methotrexate), but others remain in development (ziltivekimab, tocilizumab, Somalix, IFM-2427, anakinra, mesenchymal stem cells (MSCs), colchicine, everolimus, allopurinol, and montelukast). Most of the tested drugs have shown a limited ability to reverse atherosclerosis in animal studies. Interestingly, recombinant IL-19 (rIL-19) was shown to reduce atherosclerosis development in a time- and dose-dependent manner. A low dose of rIL-19 (1 ng/g/day) reduced aortic arch and root plaque areas by 70.1% and 32.1%, respectively, in LDLR^-/- mice. At 10 ng/g/day, rIL-19 completely eliminated atherosclerotic plaques. There were no sex differences in the effects of rIL-19 on atherosclerotic mice. Thus, low-dose rIL-19 is an effective antiatherosclerotic agent, in addition to its efficacy in intimal hyperplasia, spinal cord injury, stroke, and multiple sclerosis. We propose that IL-19 is a promising biomarker and target for the diagnosis and treatment of atherosclerosis. This review considers the role and mechanism of action of IL-19 in atherosclerosis and discusses whether IL-19 is a potential therapeutic target for this condition.

Recombinant Interleukin-19 Suppresses the Formation and Progression of Experimental Abdominal Aortic Aneurysms

Background Interleukin-19 is an immunosuppressive cytokine produced by immune and nonimmune cells, but its role in abdominal aortic aneurysm (AAA) pathogenesis is not known. This study aimed to investigate interleukin-19 expression in, and influences on, the formation and progression of experimental AAAs. Methods and Results Human specimens were obtained at aneurysm repair surgery or from transplant donors. Experimental AAAs were created in 10- to 12-week-old male mice via intra-aortic elastase infusion. Influence and potential mechanisms of interleukin-19 treatment on AAAs were assessed via ultrasonography, histopathology, flow cytometry, and gene expression profiling. Immunohistochemistry revealed augmented interleukin-19 expression in both human and experimental AAAs. In mice, interleukin-19 treatment before AAA initiation via elastase infusion suppressed aneurysm formation and progression, with attenuation of medial elastin degradation, smooth-muscle depletion, leukocyte infiltration, neoangiogenesis, and matrix metalloproteinase 2 and 9 expression. Initiation of interleukin-19 treatment after AAA creation limited further aneurysmal degeneration. In additional experiments, interleukin-19 treatment inhibited murine macrophage recruitment following intraperitoneal thioglycolate injection. In classically or alternatively activated macrophages in vitro, interleukin-19 downregulated mRNA expression of inducible nitric oxide synthase, chemokine C-C motif ligand 2, and metalloproteinases 2 and 9 without apparent effect on cytokine-expressing helper or cytotoxic T-cell differentiation, nor regulatory T cellularity, in the aneurysmal aorta or spleen of interleukin-19-treated mice. Interleukin-19 also suppressed AAAs created via angiotensin II infusion in hyperlipidemic mice. Conclusions Based on human evidence and experimental modeling observations, interleukin-19 may influence the development and progression of AAAs.

IL-10 and Its Related Superfamily Members IL-19 and IL-24 Provide Parallel/Redundant Immune-Modulation in Loa loa Infection

BACKGROUND

Interleukin-10 (IL-10) has been implicated as the major cytokine responsible for the modulation of parasite-specific responses in filarial infections; however, the role of other IL-10 superfamily members in filarial infection is less well studied.

METHODS

Peripheral blood mononuclear cells from loiasis patients were stimulated with or without filarial antigen. Cytokine production was quantified using a Luminex platform and T-cell expression patterns were assessed by flow cytometry.

RESULTS

All patients produced significant levels of IL-10, IL-13, IL-5, IL-4, and IL-9 in response to filarial antigen, indicating a common infection-driven response. When comparing microfilaria (mf)-positive and mf-negative patients, there were no significant differences in spontaneous cytokine nor in parasite-driven IL-10, IL-22, or IL-28a production. In marked contrast, mf-positive individuals had significantly increased filarial antigen-driven IL-24 and IL-19 compared to mf-negative subjects. mf-positive patients also demonstrated significantly higher frequencies of T cells producing IL-19 in comparison to mf-negative patients. T-cell expression of IL-19 and IL-24 was positively regulated by IL-10 and IL-1β. IL-24 production was also regulated by IL-37.

CONCLUSION

These data provide an important link between IL-10 and its related family members IL-19 and IL-24 in the modulation of the immune response in human filarial infections.

CLINICAL TRIALS REGISTRATION

NCT00001230.

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.

The Relationship Between Serum Concentration of Interleukin-35 and FoxP3 Polymorphism in Patients Undergoing Coronary Artery Bypass Graft Surgery

Objective

To investigate the association between interleukin-35 (IL-35) levels and single nucleotide polymorphisms (rs3761548, rs3761547) of the FoxP3 gene in coronary artery bypass grafting (CABG) patients.

Methods

We conducted a prospective study including 140 patients, who were scheduled for elective isolated on-pump CABG with cardiopulmonary bypass (CPB) from January 2017 to September 2018 in the Jorjani heart center. Blood samples were collected before and 12 hours after the operation. Serum levels of IL-35 were measured by enzyme-linked immunosorbent assay and the pattern of genetic variations was assessed using single specific primer-polymerase chain reaction.

Results

The serum concentrations of IL-35 after surgery were significantly higher than pre-surgery levels (18.4±8.3 vs. 9.89±3.2, respectively, P=0.002). There was no significant association between genotype frequencies of rs3761548 and rs3761547 and elevated IL-35 levels (P>0.05). There were significant associations between IL-35 levels and preoperative variables, including age (r=-0.34, P=0.047) and body mass index (r=-0.41, P=0.045), and intraoperative variables, including CPB time (r=0.4, P=0.02) and mean arterial pressure (r=-0.38, P=0.046), in carriers of the rs3761548 AA genotype.

Conclusion

Serum IL-35 concentrations were significantly increased in CPB patients, which may contribute to the post-CPB compensatory anti-inflammatory response syndrome. IL-35 increased levels were not influenced by FoxP3 promoter polymorphisms (rs3761548, rs3761547).

IL-19 as a Biomarker for the Severity of Acute Myocardial Infarction

BACKGROUND

Interleukin-19 (IL-19) has been shown to be involved in coronary artery diseases and atherosclerosis, while its expression in myocardial infarction is poorly understood. In this study, the dynamic increase in circulating IL-19 in acute ST-segment elevation myocardial infarction (STEMI) patients was detected.

METHOD

Both plasma IL-19 levels and IL-19 mRNA expression in peripheral blood mononuclear cells (PBMCs) from STEMI patients and chest pain syndrome (CPS) patients were detected at different time points, including 1 d, 3 d, 7 d and 14 d after treatment and on admission.

RESULTS

Compared with the CPS patients, IL-19 levels and IL-19 gene expression were significantly increased in STEMI patients and peaked at 1 d. From 1-14 d, refocusing treatment, including emergency percutaneous coronary intervention (PCI) and thrombolysis, markedly reduced IL-19 expression and promoted its recovery; of the treatments, the effect of emergency PCI was most significant. In addition, similar trends were also observed with cTnI, NT-proBNP and C-reactive protein (CRP) levels. Furthermore, correlation analysis showed that IL-19 levels were positively correlated with cTnI, NT-proBNP, CRP levels and left ventricular ejection fraction (LVEF) in STEMI patients.

CONCLUSIONS

IL-19 is correlated with the severity of acute myocardial infarction, which may be a new idea for the clinical treatment of myocardial infarction.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Reporter Cell Assessment of TLR4-Induced NF-κB Responses to Cell-Free Hemoglobin and the Influence of Biliverdin

Hemoglobin (Hb) released during red blood cell lysis can initiate TLR4-dependent signaling and trigger NF-κB activation in surrounding cells. Observations of chronic bleeding in various cancers leads us to hypothesize that Hb and Hb degradation products released from lysed RBC near cancer nests might modulate local TLR4-positive cells. We addressed the hypothesis in vitro by measuring Hb- and biliverdin (Bv)-induced NF-κB signaling in an engineered human TLR4 reporter cell model (HEK-Blue^TM hTLR4). Therein, TLR4 stimulation was assessed by measuring NF-κB-dependent secreted alkaline phosphatase (SEAP). hTLR4 reporter cells incubated with 8 ηM lipopolysaccharide (LPS) or 20-40 μM fungal mannoprotein (FM) produced significant amounts of SEAP. hTLR4 reporter cells also produced SEAP in response to human, but not porcine or bovine, Hb. HEK-Blue Null2^TM reporter cells lacking TLR4 did not respond to LPS, FM, or Hb. Bv was non-stimulatory in reporter cells. When Bv was added to Hb-stimulated reporter cells, SEAP production was reduced by 95%, but when Bv was applied during LPS and FM stimulation, SEAP production was reduced by 33% and 27%, respectively. In conclusion, Hb initiated NF-κB signaling that was dependent upon TLR4 expression and that Bv can act as a TLR4 antagonist. Moreover, this study suggests that hemorrhage and extravascular hemolysis could provide competitive Hb and Bv signaling to nearby cells expressing TLR4, and that this process could modulate NF-κB signaling in TLR4-positive cancer cells and cancer-infiltrating leukocytes.

Genetic Deletion of IL-19 (Interleukin-19) Exacerbates Atherogenesis in Il19-/-×Ldlr-/- Double Knockout Mice by Dysregulation of mRNA Stability Protein HuR (Human Antigen R)

OBJECTIVE

To test the hypothesis that loss of IL-19 (interleukin-19) exacerbates atherosclerosis. APPROACH AND RESULTS: Il19^-/- mice were crossed into Ldlr^-/- (low-density lipoprotein receptor knock out) mice. Double knockout (dKO) mice had increased plaque burden in aortic arch and root compared with Ldlr^-/- controls after 14 weeks of high-fat diet (HFD). dKO mice injected with 10 ng/g per day rmIL-19 had significantly less plaque compared with controls. qRT-PCR and Western blot analysis revealed dKO mice had increased systemic and intraplaque polarization of T cells and macrophages to proinflammatory T_h1 and M1 phenotypes, and also significantly increased TNF (tumor necrosis factor)-α expression in spleen and aortic arch compared with Ldlr^-/- controls. Bone marrow transplantation suggests that immune cells participate in IL-19 protection. Bone marrow-derived macrophages and vascular smooth muscle cells isolated from dKO mice had a significantly greater expression of inflammatory cytokine mRNA and protein compared with controls. Spleen and aortic arch from dKO mice had significantly increased expression of the mRNA stability protein HuR (human antigen R). Bone marrow-derived macrophage and vascular smooth muscle cell isolated from dKO mice also had greater HuR abundance. HuR stabilizes proinflammatory transcripts by binding AU-rich elements in the 3' untranslated region. Cytokine and HuR mRNA stability were increased in dKO bone marrow-derived macrophage and vascular smooth muscle cell, which was rescued by addition of IL-19 to these cells. IL-19-induced expression of miR133a, which targets and reduced HuR abundance; miR133a levels were lower in dKO mice compared with controls.

CONCLUSIONS

These data indicate that IL-19 is an atheroprotective cytokine which decreases the abundance of HuR, leading to reduced inflammatory mRNA stability.

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.

Interleukin 19 reduces inflammation in chemically induced experimental colitis

Inflammatory bowel disease results from chronic dysregulation of the mucosal immune system and aberrant activation of both the innate and adaptive immune responses. Interleukin (IL)-19, a member of the IL-10 family, functions as an anti-inflammatory cytokine. Here, we investigated the contribution of IL-19 to intestinal inflammation in a model of T cell-mediated colitis in mice. Inflammatory responses in IL-19-deficient mice were assessed using the 2,4,6-trinitrobenzene sulfonic acid (TNBS) model of acute colitis. IL-19 deficiency aggravated TNBS-induced colitis and compromised intestinal recovery in mice. Additionally, the exacerbation of TNBS-induced colonic inflammation following genetic ablation of IL-19 was accompanied by increased production of interferon-gamma, IL-12 (p40), IL-17, IL-22, and IL-33, and decreased production of IL-4. Moreover, the exacerbation of colitis following IL-19 knockout was also accompanied by increased production of CXCL1, G-CSF and CCL5. Using this model of induced colitis, our results revealed the immunopathological relevance of IL-19 as an anti-inflammatory cytokine in intestinal inflammation in mice.

Toll-like receptor 2 and 4 induced interleukin-19 dampens immune reactions and associates inversely with spondyloarthritis disease activity

Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases affecting joints, gut, skin and entheses. The inflammatory process involves activation of Toll-like receptor (TLR)-2 and TLR-4 and production of cytokines and chemokines such as monocyte chemoattractant protein 1 (CCL2/MCP-1). This proinflammatory chemokine recruits monocytes to sites of inflammation and is central in the development of several immune-mediated inflammatory diseases. Interleukin (IL)-19 is a member of the IL-10 family of cytokines. IL-19-deficient mice are more susceptible to innate-mediated colitis and develop more severe inflammation in response to injury. In this work, we studied inducers of IL-19 production and effect of IL-19 on the production of CCL2/MCP-1 and proinflammatory cytokines in peripheral blood mononuclear cells (PBMCs) from healthy controls (HCs) and in PBMCs and synovial fluid mononuclear cells (SFMCs) from SpA patients. Further, we measured IL-19 in plasma from HCs and in plasma and synovial fluid from SpA patients. Constitutive IL-19 expression was present in both PBMCs and SFMCs and the secretion of IL-19 was increased by TLR-2 and TLR-4 ligands. Neutralizing IL-19 in HC PBMCs and SpA SFMCs resulted in increased production of CCL-2/MCP-1. IL-19 concentrations were decreased in synovial fluid compared with plasma and associated inversely with disease activity in SpA. SpA SFMCs produced less IL-19 in response to LPS compared with HC PBMCs. These findings indicate that IL-19 production is diminished in SpA. Taken together, impaired IL-19 control of the innate immune system might be involved in the pathogenesis of SpA.

Astrocytes produce IL-19 in response to bacterial challenge and are sensitive to the immunosuppressive effects of this IL-10 family member

There is growing appreciation that resident glial cells can initiate and/or regulate inflammation following trauma or infection in the central nervous system (CNS). We have previously demonstrated the ability of microglia and astrocytes to respond to bacterial pathogens or their products by rapid production of inflammatory mediators, followed by the production of the immunosuppressive cytokine interleukin (IL)−10. IL-19, another member of the IL-10 family of cytokines, has been studied in the context of a number of inflammatory conditions in the periphery and is known to modulate immune cell activity. In the present study, we demonstrate the constitutive and/or inducible expression of IL-19 and its cognate receptor subunits, IL-19Rα and IL-19Rβ (also known as IL-20R1 and IL-20R2, and IL-20RA and IL-20RB), in mouse brain tissue, and by primary murine and human astrocytes. We also provide evidence for the presence of a novel truncated IL-19Rα transcript variant in mouse brain tissue, but not glial cells, that shows reduced expression following bacterial infection. Importantly, IL-19R functionality in glia is indicated by the ability of IL-19 to regulate signaling component expression in these cells. Furthermore, while IL-19 itself had no effect on glial cytokine production, IL-19 treatment of bacterially infected or Toll-like receptor ligand stimulated astrocytes significantly attenuated pro-inflammatory cytokine production. The bacterially induced production of IL-19 by these resident CNS cells, the constitutive expression of its cognate receptor subunits, and the immunomodulatory effects of this cytokine, suggest a novel mechanism by which astrocytes can regulate CNS inflammation.

Flow cytometric evaluation of T cell activation markers after cardiopulmonary bypass

Background. Cardiopulmonary bypass surgery (CPBS) is associated with an increased risk for infections or with subsequent organ dysfunction. As T cell activation is a central mechanism during inflammatory processes, we developed an assay to evaluate T cell activation pathways in patients undergoing CPBS. Methods. Blood was obtained from eleven patients undergoing CPBS preoperatively, on postoperative day (POD)-3, and on POD-7 and was stimulated with different concentrations of Concanavalin A (ConA). Cyclosporine and sirolimus, inhibiting different pathways of the T cell cycle, were added to blood ex vivo. Expression of T cell activation markers CD25 and CD95 was analyzed by flow cytometry. Results. In untreated blood, expression of CD25 and CD95 significantly increased with higher ConA concentrations (P < 0.05) and decreased for all ConA concentrations for both antigens over the study time (P < 0.05). Independently from the ConA concentration, inhibition of CD25 and CD95 expression was highest preoperatively for sirolimus and on POD-3 for cyclosporine. At all time points, inhibition of CD25 and CD95 expression was significantly higher after cyclosporine compared to sirolimus treatment (P < 0.001). Conclusion. Our results showed that different pathways of T cell activation are impaired after CPBS. Such knowledge may offer the opportunity to identify patients at risk for postoperative complications.

Interleukin-19 impairment in active Crohn's disease patients

The exact function of interleukin-19 (IL-19) on immune response is poorly understood. In mice, IL-19 up-regulates TNFα and IL-6 expression and its deficiency increases susceptibility to DSS-induced colitis. In humans, IL-19 favors a Th2 response and is elevated in several diseases. We here investigate the expression and effects of IL-19 on cells from active Crohn’s disease (CD) patient. Twenty-three active CD patients and 20 healthy controls (HC) were included. mRNA and protein IL-19 levels were analyzed in monocytes. IL-19 effects were determined in vitro on the T cell phenotype and in the production of cytokines by immune cells. We observed that unstimulated and TLR-activated monocytes expressed significantly lower IL-19 mRNA in active CD patients than in HC (logFC = −1.97 unstimulated; −1.88 with Pam3CSK4; and −1.91 with FSL-1; p<0.001). These results were confirmed at protein level. Exogenous IL-19 had an anti-inflammatory effect on HC but not on CD patients. IL-19 decreased TNFα production in PBMC (850.7±75.29 pg/ml vs 2626.0±350 pg/ml; p<0.01) and increased CTLA4 expression (22.04±1.55% vs 13.98±2.05%; p<0.05) and IL-4 production (32.5±8.9 pg/ml vs 13.5±2.9 pg/ml; p<0.05) in T cells from HC. IL-10 regulated IL-19 production in both active CD patients and HC. We observed that three of the miRNAs that can modulate IL-19 mRNA expression, were up-regulated in monocytes from active CD patients. These results suggested that IL-19 had an anti-inflammatory role in this study. Defects in IL-19 expression and the lack of response to this cytokine could contribute to inflammatory mechanisms in active CD patients.

Attenuation of experimental atherosclerosis by interleukin-19

OBJECTIVE

Interleukin-19 (IL-19) is a putative Th2, anti-inflammatory interleukin. Its expression and potential role in atherogenesis are unknown. IL-19 is not detected in normal artery and is expressed to a greater degree in plaque from symptomatic versus asymptomatic patients, suggesting a compensatory counter-regulatory function. We tested whether IL-19 could reduce atherosclerosis in susceptible mice and identified plausible mechanisms.

APPROACH AND RESULTS

LDLR(-/-) mice fed an atherogenic diet and injected with either 1.0 or 10.0 ng/g per day recombinant mouse IL-19 had significantly less plaque area in the aortic arch compared with controls (P<0.0001). Weight gain, cholesterol, and triglyceride levels were not significantly different. Gene expression in splenocytes from IL-19-treated mice demonstrated immune cell Th2 polarization, with decreased expression of T-bet, interferon-γ, interleukin-1β, and interleukin-12β and increased expression of GATA3 and FoxP3 mRNA. A greater percentage of lymphocytes were Th2 polarized in IL-19-treated mice. Cellular characterization of plaque by immunohistochemistry demonstrated that IL-19-treated mice have significantly less macrophage infiltrate compared with controls (P<0.001). Intravital microscopy revealed significantly less leukocyte adhesion in wild-type mice injected with IL-19 and fed an atherogenic diet compared with controls. Treatment of cultured endothelial cells, vascular smooth muscle cells, and bone marrow-derived macrophages with IL-19 resulted in a significant decrease in chemokine mRNA and mRNA stability protein human antigen R.

CONCLUSIONS

These data suggest that IL-19 is a potent inhibitor of experimental atherosclerosis, with diverse mechanisms including immune cell polarization, decrease in macrophage adhesion, and decrease in gene expression. This may identify IL-19 as a novel therapeutic to limit vascular inflammation.

Interleukin-19 in breast cancer

Inflammatory cytokines within the tumor microenvironment are linked to progression in breast cancer. Interleukin- (IL-) 19, part of the IL-10 family, contributes to a range of diseases and disorders, such as asthma, endotoxic shock, uremia, psoriasis, and rheumatoid arthritis. IL-19 is expressed in several types of tumor cells, especially in squamous cell carcinoma of the skin, tongue, esophagus, and lung and invasive duct carcinoma of the breast. In breast cancer, IL-19 expression is correlated with increased mitotic figures, advanced tumor stage, higher metastasis, and poor survival. The mechanisms of IL-19 in breast cancer have recently been explored both in vitro and in vivo. IL-19 has an autocrine effect in breast cancer cells. It directly promotes proliferation and migration and indirectly provides a microenvironment for tumor progression, which suggests that IL-19 is a prognostic marker in breast cancer and that antagonizing IL-19 may have therapeutic potential.

Interleukin (IL)-19 promoted skin wound healing by increasing fibroblast keratinocyte growth factor expression

BACKGROUND

Interleukin (IL)-19, a member of the IL-10 cytokine family, is involved in keratinocyte proliferation in psoriasis.

OBJECTIVES

We investigated the role of IL-19 in the wound-healing process in vivo and in vitro.

METHODS

Two full-thickness circular wounds (4mm in diameter) were punched into the skin of BALB/C mice. IL-19 and keratinocyte growth factor (KGF) mRNA in wounded skin were determined using real-time PCR. The wounds were treated with PBS, vehicle, IL-19 (400ng/mL), or IL-20 (400ng/mL) (n=6 in each group) twice daily and the percentage of wound healing was measured daily for 7days. In vitro, human skin fibroblast CCD966-SK cells and keratinocyte HaCaT cells were treated with IL-19 or KGF. Cell proliferation and migration were determined using bromodeoxyuridine (BrdU) and transwell assays, respectively. The expression of IL-19 and KGF mRNA was also analyzed.

RESULTS

In wounded mouse skin, IL-19 mRNA was upregulated at 12h, and KGF at 24h after the injury. Both increases in gene expression declined 72h after the skin had been wounded. The percentage of wound healing in IL-19-treated mice was higher than in control mice. In vitro, IL-19 upregulated KGF expression in the CCD966-SK cells; IL-19 was upregulated in KGF-treated HaCaT cells. KGF but not IL-19 promoted HaCaT cell proliferation. However, IL-19 significantly increased the migration of HaCaT cells. HaCaT cells treated with the cultured supernatants of IL-19-stimulated CCD966-SK cells showed significantly more proliferation than in controls.

CONCLUSIONS

IL-19 is important for cutaneous wound healing because it upregulates KGF expression.

Pro- and Anti-Inflammatory Cytokine Networks in Atherosclerosis

Despite advances in prevention and treatment, atherosclerotic vascular disease continues to account for significant morbidity, mortality, and economic burden in the western world. Our current understanding of this disease presents atherosclerosis as a chronic inflammatory process involving multiple cell types in various stages of activation, apoptosis, and necrosis. These cells include monocyte/macrophage, dendritic cells, lymphocytes, endothelial cells, and vascular smooth muscle cells. Activation of these cells and their processes is initiated and sustained by a complex network of soluble factors termed cytokines. Cytokines are produced and recognized by both inflammatory and resident vascular cells, allowing crosstalk between these two systems. Cytokines also regulate the phenotype of many of these cell types. Recognizing functions of these cytokines and their effects on cells which populate atherosclerotic plaque is key to uncovering targets of therapeutic intervention. This paper will present recent studies which describe the cellular protagonists of atherosclerosis and the role they play in formation of atherosclerotic plaque. It will also describe the cytokines which have been identified as produced by and directly affecting dysfunction of these cells. Because atherosclerosis is considered an inflammatory condition, emphasis will be placed on inflammatory cytokines and their effects on atherogenesis. We will conclude with new directions in therapeutic strategies and points of emphasis for future research.

Anti-inflammatory effects of interleukin-19 in vascular disease

Despite aggressive dietary modification, lipid-lowering medications, and other interventional medical therapy, vascular disease continues to be a leading cause of mortality in the western world. It is a significant medical and socioeconomic problem contributing to mortality of multiple diseases including myocardial infarction, stroke, renal failure, and peripheral vascular disease. Morbidity and mortality of vascular disease are expected to worsen with the increasing number of patients with comorbid conditions such as obesity, metabolic syndrome, and diabetes mellitus type 2. Vascular diseases such as atherosclerosis, restenosis, and allograft vasculopathy are recognized to be driven by inflammation, and as such, cytokines which mediate inflammation not only represent important targets of rational therapy, but also can be considered as possible therapeutic modalities themselves. In this paper, we will examine the role of inflammatory cytokines and lymphocyte T(h)1/T(h)2 polarity in vascular inflammation, with a focus on atherosclerotic vascular disease. We will then introduce a recently described T(h)2 interleukin, interleukin-19 (IL-19), as a previously unrecognized mediator of vascular inflammatory disorders. We will review our current understanding of this interleukin in health and disease and present the possibility that IL-19 could represent a potential therapeutic to combat vascular inflammatory disease.