S100A2 Is a Prognostic Biomarker Involved in Immune Infiltration and Predict Immunotherapy Response in Pancreatic Cancer.

Pancreatic cancer (PC) is a highly fatal and aggressive disease with its incidence and mortality quite discouraging. It is of great significance to construct an effective prognostic signature of PC and find the novel biomarker for the optimization of the clinical decision-making. Due to the crucial role of immunity in tumor development, a prognostic model based on nine immune-related genes was constructed, which was proved to be effective in The Cancer Genome Atlas (TCGA) training set, TCGA testing set, TCGA entire set, GSE78229 set, and GSE62452 set. Furthermore, S100A2 (S100 Calcium Binding Protein A2) was identified as the gene occupying the most paramount position in risk model. Gene set enrichment analysis (GSEA), ESTIMATE and CIBERSORT algorithm revealed that S100A2 was closely associated with the immune status in PC microenvironment, mainly related to lower proportion of CD8+T cells and activated NK cells and higher proportion of M0 macrophages. Meanwhile, patients with high S100A2 expression might get more benefit from immunotherapy according to immunophenoscore algorithm. Afterwards, our independent cohort was also used to demonstrate S100A2 was an unfavorable marker of PC, as well as its remarkably positive correlation with the expression of PD-L1. In conclusion, our results demonstrate S100A2 might be responsible for the preservation of immune-suppressive status in PC microenvironment, which was identified with significant potentiality in predicting prognosis and immunotherapy response in PC patients.

Biology, role and therapeutic potential of circulating histones in acute inflammatory disorders.

Histones are positively charged nuclear proteins that facilitate packaging of DNA into nucleosomes common to all eukaryotic cells. Upon cell injury or cell signalling processes, histones are released passively through cell necrosis or actively from immune cells as part of extracellular traps. Extracellular histones function as microbicidal proteins and are pro-thrombotic, limiting spread of infection or isolating areas of injury to allow for immune cell infiltration, clearance of infection and initiation of tissue regeneration and repair. Histone toxicity, however, is not specific to microbes and contributes to tissue and end-organ injury, which in cases of systemic inflammation may lead to organ failure and death. This review details the processes of histones release in acute inflammation, the mechanisms of histone-related tissue toxicity and current and future strategies for therapy targeting histones in acute inflammatory diseases.

Relation between serum levels of chemotaxis-related factors and the presence of coronary artery calcification as expression of subclinical atherosclerosis.

BACKGROUND: Atherosclerotic plaque formation is characterized by recruitment of monocytes/macrophages, which contributes to its calcification by releasing pro-osteogenic cytokines. Chemotaxis-related proteins, including netrin-1, gremlin-1 and macrophage inflammatory protein-1ß (MIP-1ß), regulate immune cell migration. However, their relation with the presence of subclinical atherosclerosis, assessed by measures of coronary artery calcifications (CAC) in patients without known coronary artery disease (CAD), remains unclear. AIMS: To examine whether these chemoattractant-related proteins are associated with the presence of CAC in patients without known CAD. METHODS: A retrospective case-control observational study was conducted in 120 outpatients without CAD, undergoing a CAC evaluation by computed tomography with the Agatston Calcium score, categorized as CAC- (none) and CAC+ (≥1). Serum biomarkers were quantified by ELISA. RESULTS: Lpa, dyslipidaemia and smoking were significantly higher (p=0.006, p≤0.0001 and p=0.001, respectively) in CAC+ patients. Serum netrin-1 levels were lower in CAC+ than in CAC- patients (196.8±127.8pg/ml versus 748.3±103.2pg/ml, p≤0.0001), and a similar pattern was found for gremlin-1 (1.14±0.39ng/ml versus 4.33±1.20ng/ml, p≤0.0001). However, TNFα and MIP-1ß were strongly upregulated in CAC+ patients (447.56±74pg/ml versus 1104±144pg/ml and 402.00±94pg/ml versus 905.0±101.6pg/ml, respectively, p≤0.001). Multivariate analyses revealed that low netrin-1 and gremlin-1 levels and high TNFα and MIP-1ß amounts were associated with CAC presence, after adjustment for clinical and biochemical variables. CONCLUSIONS: We found a netrin-1 and gremlin-1 deficiency and a TNFα and MIP-1ß overproduction in CAC+ patients' serum. These proteins may be used to identify individuals with subclinical atherosclerosis. Further research is warranted in a larger cohort of patients to establish these chemotactic-related proteins as biomarkers that improve CAD risk stratification.

Citrus flavanones prevent systemic inflammation and ameliorate oxidative stress in C57BL/6J mice fed high-fat diet.

The flavanones hesperidin, eriocitrin and eriodictyol were investigated for their prevention of the oxidative stress and systemic inflammation caused by high-fat diet in C57BL/6J mice. The mice received a standard diet (9.5% kcal from fat), high-fat diet (45% kcal from fat) or high-fat diet supplemented with hesperidin, eriocitrin or eriodictyol for a period of four weeks. Hesperidin, eriocitrin and eriodictyol increased the serum total antioxidant capacity, and restrained the elevation of interleukin-6 (IL-6), macrophage chemoattractant protein-1 (MCP-1), and C-reactive protein (hs-CRP). In addition, the liver TBARS levels and spleen mass (g per kg body weight) were lower for the flavanone-treated mice than in the unsupplemented mice. Eriocitrin and eriodictyol reduced TBARS levels in the blood serum, and hesperidin and eriodictyol also reduced fat accumulation and liver damage. The results showed that hesperidin, eriocitrin and eriodictyol had protective effects against inflammation and oxidative stress caused by high-fat diet in mice, and may therefore prevent metabolic alterations associated with the development of cardiovascular diseases in other animals.

Influence and analysis of low-dosage steroid therapy in severe aristolochic acid nephropathy patients.

AIM: To investigate the effect of low-dosage steroid therapy in patients with severe aristolochic acid nephropathy (AAN). METHODS: Forty-three chronic AAN patients in the Peking Union Medical College Hospital and the First Affiliated Hospital of Xinxiang Medical College were included in this study from November 1998 to October 2013. According to the treatment method, the patients were divided into a steroid group (SG, n = 25) and a control group (CG, n = 18). The serum biochemical indicators at the basement in the two groups exhibited no obvious statistical differences. In comparison with the baseline data, the levels of serum creatinine at 3, 6, 9, and 12 months were analyzed. The blood pressure, haemoglobin, serum biochemical indicators, and the side-effects of steroid application were also observed. Urinary macrophage chemoattractant protein-1 (MCP-1) and transforming growth factor-1 (TGF-1) amounts were measured as well. RESULTS: (i) The serum creatinine content in the CG group was significantly higher than the baseline level during the follow-up(6, 9, and 12 months later), whereas in the SG group it decreased during the 3-6 month period and remained stable within 1 year. (ii) The biochemical indicators, blood pressure, and haemoglobin persisted stable. (iii) The side-effects of low-dosage steroid therapy were not severe and were tolerated by the AAN patients. (4) Urinary MCP-1 and TGF-1 concentrations were positively correlated with serum creatinine and decreased in the SG group. CONCLUSION: Low-dosage steroid therapy reversed or delayed the renal failure progression in severe chronic AAN patients, which may be associated with the suppression of MCP-1 and TGF-ß1 activities.

Diagnostic significance of S100A2 and S100A6 levels in sera of patients with non-small cell lung cancer.

Biochemical markers play a significant role in the diagnosis of lung cancer. Recent studies have demonstrated a link involving S100 Calcium Binding Proteins (S100A2, S100A6) and non-small cell lung cancer (NSCLC), but the expediency of their serum levels in NSCLC has not been established. In this study, we evaluate the potential of serum S100A2 and S100A6 levels as diagnostic markers for NSCLC. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the levels of S100A2 and S100A6 in 141 NSCLC patients and 150 healthy subjects. Serum levels of the two proteins in patients with NSCLC were higher compared to healthy controls (P = 0.0002 for S100A2 and P < 0.0001 for S100A6). Moreover, the levels of S100A2 and S100A6 were higher in the sera of stage I/II NSCLC patients compared to healthy controls with P = 0.01 and <0.0001, respectively. Receiver operating characteristic (ROC) analysis showed that S100A2 could distinguish NSCLC patients from healthy controls (AUC = 0.646), and S100A6 could also identify NSCLC (AUC = 0.668). Meanwhile, these two proteins showed notable capabilities for distinguishing stage I/II NSCLC from healthy controls (AUC = 0.708 for S100A2 and AUC = 0.702 for S100A6). Our results indicate that serum levels of S100A2 and S100A6 are significantly elevated in early stage NSCLC and may have the potential for NSCLC biomarker. Further studies with large sample population would help validate our findings.

A randomized controlled trial on the effects of goal-directed therapy on the inflammatory response open abdominal aortic aneurysm repair.

INTRODUCTION: Goal-directed therapy (GDT) has been shown in numerous studies to decrease perioperative morbidity and mortality. The mechanism of benefit of GDT, however, has not been clearly elucidated. Targeted resuscitation of the vascular endothelium with GDT might alter the postoperative inflammatory response and be responsible for the decreased complications with this therapy. METHODS: This trial was registered at ClinicalTrials.gov as NCT01681251. Forty patients undergoing elective open repair of their abdominal aortic aneurysm, 18 years of age and older, were randomized to an interventional arm with GDT targeting stroke volume variation with an arterial pulse contour cardiac output monitor, or control, where fluid therapy was administered at the discretion of the attending anesthesiologist. We measured levels of several inflammatory cytokines (C-reactive protein, Pentraxin 3, suppressor of tumorgenicity--2, interleukin-1 receptor antagonist, and tumor necrosis factor receptor-III) preoperatively and at several postoperative time points to determine if there was a difference in inflammatory response. We also assessed each group for a composite of postoperative complications. RESULTS: Twenty patients were randomized to GDT and twenty were randomized to control. Length of stay was not different between groups. Intervention patients received less crystalloid and more colloid. At the end of the study, intervention patients had a higher cardiac index (3.4 ± 0.5 vs. 2.5 ± 0.7 l/minute per m(2), p < 0.01) and stroke volume index (50.1 ± 7.4 vs. 38.1 ± 9.8 ml/m(2), p < 0.01) than controls. There were significantly fewer complications in the intervention than control group (28 vs. 12, p = 0.02). The length of hospital and ICU stay did not differ between groups. There was no difference in the levels of inflammatory cytokines between groups. CONCLUSIONS: Despite being associated with fewer complications and improved hemodynamics, there was no difference in the inflammatory response of patients treated with GDT. This suggests that the clinical benefit of GDT occurs in spite of a similar inflammatory burden. Further work needs to be performed to delineate the mechanism of benefit of GDT. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01681251 . Registered 18 May 2011.

Patients with pancreatic adenocarcinoma exhibit elevated levels of myeloid-derived suppressor cells upon progression of disease.

Elevated levels of myeloid-derived suppressor cells (MDSCs) induced by tumor-derived factors are associated with inhibition of immune responses in patients with gastrointestinal malignancies. We hypothesized that pro-MDSC cytokines and levels of MDSC in the peripheral blood would be elevated in pancreatic adenocarcinoma patients with progressive disease. Peripheral blood mononuclear cells (PBMCs) were isolated from 16 pancreatic cancer patients undergoing chemotherapy and phenotyped for MDSC using a five antigen panel (CD33, HLA-DR, CD11b, CD14, CD15). Patients with stable disease had significantly lower MDSC levels in the peripheral blood than those with progressive disease (1.41 ± 1.12 vs. 5.14 ± 4.58 %, p = 0.013, Wilcoxon test). A cutoff of 2.5 % MDSC identified patients with progressive disease. Patients with ECOG performance status ≥2 had a weaker association with increased levels of MDSC. Plasma was obtained from 15 chemonaive patients, 13 patients undergoing chemotherapy and 9 normal donors. Increases in the levels of pro-MDSC cytokines were observed for pancreatic cancer patients versus controls, and the pro-MDSC cytokine IL-6 was increased in those patients undergoing chemotherapy. This study suggests that MDSC in peripheral blood may be a predictive biomarker of chemotherapy failure in pancreatic cancer patients.

Contrasting effects of cold acclimation versus obesogenic diets on chemerin gene expression in brown and brite adipose tissues.

Based on results from a signal sequence trap, we investigated chemerin gene expression in brown adipose tissue. Male NMRI mice were exposed to 30, 22 or 4 °C for 3 weeks, or were fed control (chow) diet, cafeteria diet or high-fat diet at thermoneutrality for the same time. In brown adipose tissue, cold acclimation strongly diminished chemerin gene expression, whereas obesogenic diets augmented expression. Qualitatively, changes in expression were paralleled in brite/beige adipose tissues (e.g. inguinal), whereas white adipose tissue (epididymal) and muscle did not react to these cues. Changes in tissue expression were not directly paralleled by alterations in plasma levels. Both these intact animal studies and brown adipocyte cell culture studies indicated that the gene expression regulation was not congruent with a sympathetic/adrenergic control. The data are discussed in relation to suggested endocrine, paracrine and autocrine effects of chemerin.

Decreased level of sRAGE in the cerebrospinal fluid of multiple sclerosis patients at clinical onset.

OBJECTIVES: Receptor for advanced glycation end products (RAGE) ligands/RAGE interactions have been proposed to have a pathogenic role in neuroinflammatory disorders. Our study aimed to assess changes in high-mobility group box (HMGB)1 and its receptor RAGE in peripheral blood (PBL) and cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) at the disease onset compared with control subjects. METHODS: PBL and CSF were collected from control subjects (n = 30) and MS patients (n = 27) at clinical onset. Soluble RAGE (sRAGE), HMGB1, S100 calcium-binding protein A12 (S100A12), interleukin (IL)-1ß and tumor necrosis factor (TNF)-α were measured in the CSF and plasma by enzyme-linked immunosorbent assay. Gene expression in PBL mononuclear cells (PBMCs) was detected by quantitative PCR for RAGE, HMGB1, S100A12 and several proinflammatory/immunoregulatory cytokines. RESULTS: We found a significantly lower expression of IL-10 (p = 0.031) in the PBMCs of MS patients. The level of sRAGE in the CSF of MS patients was lower (p = 0.021), with the ability to discriminate between MS patients and control subjects. Moreover, PBMC gene expression for HMGB1 and S100A12 positively correlated with IL-6. CONCLUSIONS: Our study confirmed that the cytokine network is disturbed in PBL and CSF at MS clinical onset. The deregulated HMGB1/RAGE axis found in our study may present an early pathogenic event in MS, proposing sRAGE as a possible novel therapeutic strategy for MS treatment.

A blood-based biomarker panel to detect acute stroke.

BACKGROUND: The aim of this study was to develop an adjunctive, peripheral biomarker test to differentiate ischemic strokes, intracranial hemorrhages (ICHs), and stroke mimics in the acute setting. METHODS: Serum samples were collected from 167 patients who presented with an acute neurologic deficit within 24 hours of symptom onset. Patients were adjudicated to ischemic stroke, ICH, and mimic pathology groups based on clinical and radiographic findings. Samples were tested for levels of 262 potential markers. A multivariate Cox proportional hazards regression model of 5 biomarkers was built by stepwise selection and validated by bootstrapping. Its discriminative capacity was quantified by C index and net reclassification improvement (NRI). RESULTS: The final model consisted of eotaxin, epidermal growth factor receptor, S100A12, metalloproteinase inhibitor-4, and prolactin. It demonstrated a discriminative capacity for ischemic stroke versus mimic (C = .92), ischemic stroke and ICH versus mimic (C = .93), and ischemic stroke versus ICH (C = .82). The inclusion of biomarkers to a model consisting of age, race, and gender resulted in an NRI of 161% when detecting ischemic stroke versus mimic (P < .0001), an improvement of 171% when detecting ischemic strokes plus ICH versus mimic (P < .0001), and an improvement of 56% when detecting ischemic strokes versus ICH (P = .1419). CONCLUSIONS: These results suggest that information obtained from a 5-biomarker panel may add valuable information in the early evaluation and management of patients with stroke-like symptoms.

Inhibition of keratinocyte proliferation by phospholipid-conjugates of a TLR7 ligand in a Myc-induced hyperplastic actinic keratosis model in the absence of systemic side effects.

BACKGROUND: The Toll-like receptor 7 (TLR7) activator imiquimod (IMQ) is safe and effective in treating actinic keratosis; however, an intermittent treatment regimen is necessary because of excessive local reactions. OBJECTIVES: To evaluate in vitro potency, pharmacodynamics/pharmacokinetics, toxicity and efficacy in vivo of the newly developed TLR7 ligand-phospholipid conjugate, TMX-202, in a gel formulation. MATERIAL AND METHODS: The effects of TMX-202 were assessed both in vitro on a murine macrophage cell line and in primary bone marrow-derived dendritic cells and in vivo on mice (C57BL/6-wild type, Myd88(-/-) and Tlr7(-/-)). RESULTS: TMX-202 was more potent than IMQ in vitro using murine and human cells. In contrast, in vivo it showed less systemic pro-inflammatory activity and better safety than IMQ. Moreover, the TMX-202 gel formulation exhibited at least comparable efficacy to Aldara in a mouse model for skin proliferative diseases. CONCLUSION: TMX-202 is safe and efficacious without causing excessive adverse effects, suggesting that it may be an alternative to Aldara for the treatment of proliferative skin conditions.

Stress-induced effects, which inhibit host defenses, alter leukocyte trafficking.

Acute cold restraint stress (ACRS) has been reported to suppress host defenses against Listeria monocytogenes, and this suppression was mediated by beta1-adrenoceptors (ß1-ARs). Although ACRS appears to inhibit mainly early innate immune defenses, interference with leukocyte chemotaxis and the involvement of ß1-AR (or ß2-AR) signaling had not been assessed. Thus, the link between sympathetic nerve stimulation, release of neurotransmitters, and changes in blood leukocyte profiles, including oxidative changes, following ACRS was evaluated. The numbers of leukocyte subsets in the blood were differentially affected by ß1-ARs and ß2-ARs following ACRS; CD3(+) (CD4 and CD8) T-cells were shown to be decreased following ACRS, and the T cell lymphopenia was mediated mainly through a ß2-AR mechanism, while the decrease in CD19(+) B-cells was influenced through both ß1- and ß2-ARs, as assessed by pharmacological and genetic manipulations. In contrast to the ACRS-induced loss of circulating lymphocytes, the number of circulating neutrophils was increased (i.e., neutrophilia), and this neutrophilia was mediated through ß1-ARs. The increase in circulating neutrophils was not due to an increase in serum chemokines promoting neutrophil emigration from the bone marrow; rather it was due to neutrophil release from the bone marrow through activation of a ß1-AR pathway. There was no loss of glutathione in any of the leukocyte subsets suggesting that there was minimal oxidative stress; however, there was early production of nitric oxide and generation of some protein radicals. Premature egress of neutrophils from bone marrow is suggested to be due to norepinephrine induction of nitric oxide, which affects the early release of neutrophils from bone marrow and lessens host defenses.

Adipocyte chemerin release is induced by insulin without being translated to higher levels in vivo.

BACKGROUND: Chemerin is an adipokine that regulates insulin sensitivity and insulin secretion. Prolonged hyperinsulinaemia is associated with higher systemic chemerin, and insulin induces adipose tissue chemerin release. These findings led us to hypothesize that systemic chemerin may be associated with post-prandial glucose metabolism and/or may even be induced after oral glucose load. Therefore, the effect of insulin on adipocyte chemerin levels and systemic chemerin in mice was analysed. Further, systemic levels of chemerin after oral glucose load in nondiabetic individuals were studied. DESIGN AND METHODS: Chemerin levels were determined in adipocytes after short-term and long-term treatment with insulin. Effects of acute hyperinsulinaemia were studied in mice. Chemerin was measured during oral glucose tolerance test in 66 healthy, nondiabetic individuals stratified for established body mass index categories. RESULTS: Insulin induces chemerin release from adipocytes within 24 h, while cellular levels are not affected. Short-term hyperinsulinaemia also upregulates adipocyte chemerin in vitro but has no effect on adipose tissue and chemerin serum levels of mice. Systemic chemerin is higher in overweight/obese than normal-weight controls and positively correlates with total cholesterol. Chemerin is not associated with markers of insulin sensitivity like fasting glucose or insulin. Fasting chemerin levels are similar to concentrations measured 1 and 2 h after oral glucose uptake in overweight and obese donors. CONCLUSIONS: Post-prandial hyperinsulinaemia does not contribute to higher chemerin levels in nondiabetic individuals.

Expression, regulation, and function of atypical chemerin receptor CCRL2 on endothelial cells.

Chemokine (CC motif) receptor-like 2 (CCRL2) binds leukocyte chemoattractant chemerin and can regulate local levels of the attractant, but does not itself support cell migration. In this study, we show that CCRL2 and VCAM-1 are upregulated on cultured human and mouse vascular endothelial cells (EC) and cell lines by proinflammatory stimuli. CCRL2 induction is dependent on NF-κB and JAK/STAT signaling pathways, and activated endothelial cells specifically bind chemerin. In vivo, CCRL2 is constitutively expressed at high levels by lung endothelial cells and at lower levels by liver endothelium; and liver but not lung EC respond to systemic LPS injection by further upregulation of the receptor. Plasma levels of total chemerin are elevated in CCRL2(-/-) mice and are significantly enhanced after systemic LPS treatment in CCRL2(-/-) mice compared with wild-type mice. Following acute LPS-induced pulmonary inflammation in vivo, chemokine-like receptor 1 (CMKLR1)(+) NK cell recruitment to the airways is significantly impaired in CCRL2(-/-) mice compared with wild-type mice. In vitro, chemerin binding to CCRL2 on endothelial cells triggers robust adhesion of CMKLR1(+) lymphoid cells through an α(4)ß(1) integrin/VCAM-1-dependent mechanism. In conclusion, CCRL2 is expressed by EC in a tissue- and activation-dependent fashion, regulates circulating chemerin levels and its bioactivity, and enhances chemerin- and CMKLR1-dependent lymphocyte/EC adhesion in vitro and recruitment to inflamed airways in vivo. Its expression and/or induction on EC by proinflammatory stimuli provide a novel and specific mechanism for the local enrichment of chemerin at inflammatory sites, regulating the recruitment of CMKLR1(+) cells.

INCB38579, a novel and potent histamine H4 receptor small molecule antagonist with anti-inflammatory pain and anti-pruritic functions.

The histamine H4 receptor mediates several histamine-induced cellular functions of leukocytes, including cell migration and cytokine production. Recent studies suggest that histamine signaling through the histamine H4 receptor can also have anti-pruritic and anti-nociceptive functions. 1-(7-(2-amino-6-(4-methylpiperazin-1-yl) pyrimidin-4-yl)-3, 4-dihdroisoquinolin-2(1H)-yl)-2-cyclopentylethanone (INCB38579) is a novel small molecule antagonist of the human and rodent histamine H4 receptors with at least 80-fold selectivity over the human histamine H1, H2 and H3 receptors, and has good pharmacokinetic properties in rats and mice. The compound is potent in inhibiting histamine binding to and signaling through the recombinant human, mouse and rat histamine H4 receptors and blocks the histamine-induced migration of human and mouse dendritic cells, as well as the cell shape change and migration of human eosinophils. INCB38579 and histamine may have separate but overlapping binding sites on the human histamine H4 receptor. This novel inhibitor is efficacious when evaluated in two previously established in vivo models for histamine H4 receptor activity (histamine-induced itch in mice and carrageenan-induced acute inflammatory pain in rats). When examined in formalin-induced pain models, INCB38579 significantly reduces the sustained inflammatory pain experienced by rats and mice. A good correlation between the protein binding adjusted potency from in vitro studies and its analgesic effect in vivo was observed. These results suggest that INCB38579 can serve as a useful tool for pharmacologic characterization of the histamine H4 receptor and further support the hypothesis that targeting the histamine H4 receptor may provide new therapeutic agents for various chronic inflammatory diseases, including inflammatory pain.

Regulation of chemerin chemoattractant and antibacterial activity by human cysteine cathepsins.

Chemerin, a ligand for the G-protein coupled receptor chemokine-like receptor 1, requires C-terminal proteolytic processing to unleash its chemoattractant activity. Proteolytically processed chemerin selectively attracts specific subsets of immunoregulatory APCs, including chemokine-like receptor 1-positive immature plasmacytoid dendritic cells (pDC). Chemerin is predicted to belong to the structural cathelicidin/cystatin family of proteins composed of antibacterial polypeptide cathelicidins and inhibitors of cysteine proteinases (cystatins). We therefore hypothesized that chemerin may interact directly with cysteine proteases, and that it might also function as an antibacterial agent. In this article, we show that chemerin does not inhibit human cysteine proteases, but rather is a new substrate for cathepsin (cat) K and L. cat K- and L-cleaved chemerin triggered robust migration of human blood-derived pDC ex vivo. Furthermore, cat K- and L-truncated chemerin also displayed antibacterial activity against Enterobacteriaceae. Cathepsins may therefore contribute to host defense by activating chemerin to directly inhibit bacterial growth and to recruit pDC to sites of infection.

Role of ribosomal protein S19-like plasma protein in blood coagulum resorption.

Western blot analyses and monocyte chemoattraction analyses of guinea pig plasma and serum indicated the presence of a plasma protein indistinguishable from ribosomal protein S19 and the cross-linked dimerization of it gaining monocyte chemotactic capacity in association with blood coagulation as in the case of human. When coagula preformed in vitro were intraperitoneally inserted into guinea pigs, they were rapidly covered by macrophages within 24h concomitant with an intra-coagulum macrophage infiltration. Differences were observed between the surface macrophages and the penetrating macrophages in ultrastructural, histochemical and immunohistochemical analyses. The inserted coagula were resorbed by day 7. When either anti-RP S19 antibodies or Gln137Asn-RP S19, a competitive inhibitor against RP S19, was premixed into the inserted coagulum, the attachment and penetration by macrophages decreased and the coagulum resorption retarded. These results indicate the role of the plasma RP S19-like molecule in coagulum resorption via macrophage recruitment.

Serum chemerin levels vary with time of day and are modified by obesity and tumor necrosis factor-{alpha}.

Chemerin is an adipokine with important regulatory roles in adipogenesis. In humans, serum total chemerin (i.e. prochemerin plus chemerin) levels are positively associated with body mass index and metabolic syndrome. However, the mechanisms that increase serum chemerin concentration are unknown. We hypothesized that chronic low-grade inflammation that occurs in obesity promotes chemerin production by adipocytes. Consistent with this, TNFalpha treatment of 3T3-L1 adipocytes increased bioactive chemerin levels in the cell media as detected using a CMKLR1 cell-based bioassay. This effect was blocked by the protein synthesis inhibitor cycloheximide and protein secretion inhibitor brefeldin A, indicating that TNFalpha may enhance prochemerin synthesis and secretion from adipocytes. In vivo, TNFalpha produced a time-dependent increase in serum total chemerin and bioactive chemerin. Bioactive chemerin was produced by primary mouse adipocytes and hepatocytes. Only primary adipocyte-derived chemerin was responsive to TNFalpha regulation implicating adipocytes as a potential source of elevated serum chemerin after TNFalpha exposure in vivo. In lean mice, serum total chemerin levels oscillated with peak levels occurring during daytime and trough levels at night. Comparatively, leptin- and leptin receptor-deficient obese mice, which have elevated adipose tissue expression of TNFalpha, displayed elevated serum total chemerin levels with an enhanced oscillatory pattern. In summary, our novel results identified TNFalpha as a positive regulator of adipocyte-derived chemerin. We corroborate the finding of elevated chemerin in obese humans by identifying elevated serum levels of total chemerin in two obese mouse models with a corresponding alteration in the rhythmic pattern of serum chemerin levels.

Chemerin exacerbates glucose intolerance in mouse models of obesity and diabetes.

Obesity, characterized by an excess of adipose tissue, is an established risk factor for cardiovascular disease and type 2 diabetes. Different mechanisms linking obesity with these comorbidities have been postulated but remain poorly understood. Adipose tissue secretes a number of hormone-like compounds, termed adipokines, that are important for the maintenance of normal glucose metabolism. Alterations in the secretion of adipokines with obesity are believed to contribute to the undesirable changes in glucose metabolism that ultimately result in the development of type 2 diabetes. In the present study, we have shown that serum levels of the novel adipokine chemerin are significantly elevated in mouse models of obesity/diabetes. The expression of chemerin and its receptors, chemokine-like receptor 1, chemokine (C-C motif) receptor-like 2, and G protein-coupled receptor 1 are altered in white adipose, skeletal muscle, and liver tissue of obese/diabetic mice. Administration of exogenous chemerin exacerbates glucose intolerance, lowers serum insulin levels, and decreases tissue glucose uptake in obese/diabetic but not normoglycemic mice. Collectively, these data indicate that chemerin influences glucose homeostasis and may contribute to the metabolic derangements characteristic of obesity and type 2 diabetes.