Trypanosoma cruzi Infection of Cultured Adipocytes Results in an Inflammatory Phenotype

Infection with Trypanosoma cruzi, the etiologic agent of Chagas disease is accompanied by an intense inflammatory reaction. Our laboratory group has identified adipose tissue as one of the major sites of inflammation during disease progression. Because adipose tissue is composed of many cell types, we were interested in investigating whether the adipocyte per se was a source of inflammatory mediators in this infection. Cultured adipocytes were infected with the Tulahuen strain of T. cruzi for 48–96 h. Immunoblot and quantitative PCR (qPCR) analyses demonstrated an increase in the expression of proinflammatory cytokines and chemokines, including interleukin (IL)‐1β, interferon‐γ, tumor necrosis factor‐α, CCL2, CCL5, and CXCL10 as well as an increase in the expression of Toll‐like receptors‐2 and 9 and activation of the notch pathway. Interestingly, caveolin‐1 expression was reduced while cyclin D1 and extracellular signal‐regulated kinase (ERK) expression was increased. The expression of PI3kinase and the activation of AKT (phosphorylated AKT) were increased suggesting that infection may induce components of the insulin/IGF‐1 receptor cascade. There was an infection‐associated decrease in adiponectin and peroxisome proliferator‐activated receptor‐γ (PPAR‐γ). These data provide a mechanism for the increase in the inflammatory phenotype that occurs in T. cruzi‐infected adipocytes. Overall, these data implicate the adipocyte as an important target of T. cruzi, and one which contributes significantly to the inflammatory response observed in Chagas disease.     

The inflammatory microenvironment in colorectal neoplasia

Colorectal cancer (CRC) is a major cause of mortality and morbidity worldwide. Inflammatory activity within the stroma of invasive colorectal tumours is known to be a key predictor of disease activity with type, density and location of immune cells impacting on patient prognosis. To date, there has been no report of inflammatory phenotype within pre-malignant human colonic adenomas. Assessing the stromal microenvironment and particularly, inflammatory activity within colorectal neoplastic lesions is central to understanding early colorectal carcinogenesis. Inflammatory cell infiltrate was assessed by immunohistochemistry in paired colonic adenoma and adjacent normal colonic mucosa samples, and adenomas exhibiting increasing degrees of epithelial cell dysplasia. Macrophage phenotype was assessed using double stain immunohistochemistry incorporating expression of an intracellular enzyme of function. A targeted array of inflammatory cytokine and receptor genes, validated by RT-PCR, was used to assess inflammatory gene expression. Inflammatory cell infiltrates are a key feature of sporadic adenomatous colonic polyps with increased macrophage, neutrophil and T cell (specifically helper and activated subsets) infiltration in adenomatous colonic polyps, that increases in association with characteristics of high malignant potential, namely, increasing degree of cell dysplasia and adenoma size. Macrophages within adenomas express iNOS, suggestive of a pro-inflammatory phenotype. Several inflammatory cytokine genes (CXCL1, CXCL2, CXCL3, CCL20, IL8, CCL23, CCL19, CCL21, CCL5) are dysregulated in adenomas. This study has provided evidence of increased inflammation within pre-malignant colonic adenomas. This may allow potential mechanistic pathways in the initiation and promotion of early colorectal carcinogenesis to be identified.     

Improved insulin sensitivity and adiponectin level after exercise training in obese Korean youth

Objective: The objective of this study was to investigate the association among adiposity, insulin resistance, and inflammatory markers [high‐sensitivity C‐reactive protein (hs‐CRP), interleukin (IL)‐6, and tumor necrosis factor (TNF)‐α] and adiponectin and to study the effects of exercise training on adiposity, insulin resistance, and inflammatory markers among obese male Korean adolescents. Research Methods and Procedures: Twenty‐six obese and 14 lean age‐matched male adolescents were studied. We divided the obese subjects into two groups: obese exercise group (N = 14) and obese control group (N = 12). The obese exercise group underwent 6 weeks of jump rope exercise training (40 min/d, 5 d/wk). Adiposity, insulin resistance, lipid profile, hs‐CRP, IL‐6, TNF‐α, and adiponectin were measured before and after the completion of exercise training. Results: The current study demonstrated higher insulin resistance, total cholesterol, LDL‐C levels, triglyceride, and inflammatory markers and lower adiponectin and HDL‐C in obese Korean male adolescents. Six weeks of increased physical activity improved body composition, insulin sensitivity, and adiponectin levels in obese Korean male adolescents without changes in TNF‐α, IL‐6, and hs‐CRP. Discussion: Obese Korean male adolescents showed reduced adiponectin levels and increased inflammatory cytokines. Six weeks of jump rope exercise improved triglyceride and insulin sensitivity and increased adiponectin levels.     

Insulin, leptin, and adiponectin receptors in colon: regulation relative to differing body adiposity independent of diet and in response to dimethylhydrazine

Obesity has recently become a focus of research to elucidate diet and lifestyle factors as important risk factors for colon cancer. Altered levels of insulin, leptin, and adiponectin have been identified as potential candidates increasing colon cancer risk within the prevailing obesogenic environment. There has been considerable research to characterize signaling via these hormones in the brain, liver, and adipose tissue; however, very little is known of their emerging role in peripheral signaling, particularly in epithelial tissues. This study profiles insulin, leptin, and adipokine receptors in the rat colon, revealing novel microanatomical location of these receptors and thereby supporting a potential role in regulating colonic tissue. Potential involvement of insulin, leptin, and adiponectin receptors in increased risk of colon cancer was investigated using Sprague-Dawley rats, either resistant or susceptible to diet-induced obesity. Regulation of insulin, leptin, and adiponectin receptors as a consequence of differing levels of adiposity was assessed regionally in the colon in response to treatment with the chemical carcinogen 1,2-dimethylhydrazine (DMH). However, significantly increased fat mass, increased levels of plasma insulin, leptin, and triglycerides, previously associated with an increased risk of colon cancer, were not associated with promotion of precancerous lesions in the experimental rats or deregulation of insulin, leptin, or adiponectin receptors. These findings do not support a direct link between the deregulation of insulin and adipokine levels observed in obese rats and an increased risk of colon carcinogenesis.     

Borrelia burgdorferi BbHtrA degrades host ECM proteins and stimulates release of inflammatory cytokines in vitro

The Lyme disease spirochaete, Borrelia burgdorferi, causes damage to diverse host tissues and induces inflammation but the mechanisms of injury are poorly understood. We recently reported that a surface‐exposed B. burgdorferi protease, which is expressed during human disease and is conserved within the major Lyme disease spirochaete species, degrades the extracellular matrix proteoglycan, aggrecan. Here we demonstrate that BbHtrA also degrades fibronectin and numerous proteoglycans found in skin, joints and neural tissues. BbHtrA degradation of fibronectin released known pro‐inflammatory fibronectin fragments FnIII_13–14 and Fnf‐29, which may amplify the inflammatory processes triggered by the presence of the bacteria. When this hypothesis was tested directly by exposing chondrocytes to BbHtrA in vitro, inflammatory cytokines (sICAM‐1 and IL‐6) and chemokines (CXCL1, CCL1, CCL2 and CCL5) that are hallmarks of Lyme disease were induced. These results provide the first evidence that, by utilizing BbHtrA, B. burgdorferi may actively participate in its dissemination and in the tissue damage and inflammation observed in Lyme disease.     

Defining a pro‐inflammatory neutrophil phenotype in response to schistosome eggs

Neutrophils contribute to the pathological processes of a number of inflammatory disorders, including rheumatoid arthritis, sepsis and cystic fibrosis. Neutrophils also play prominent roles in schistosomiasis japonica liver fibrosis, being central mediators of inflammation following granuloma formation. In this study, we investigated the interaction between Schistosoma japonicum eggs and neutrophils, and the effect of eggs on the inflammatory phenotype of neutrophils. Our results showed significant upregulated expression of pro‐inflammatory cytokines (IL‐1α, IL‐1β and IL‐8) and chemokines (CCL3, CCL4 and CXCL2) in neutrophils after 4 h in vitro stimulation with S. japonicum eggs. Furthermore, mitochondrial DNA was released by stimulated neutrophils, and induced the production of matrix metalloproteinase 9 (MMP‐9), a protease involved in inflammation and associated tissue destruction. We also found that intact live eggs and isolated soluble egg antigen (SEA) triggered the release of neutrophil extracellular traps (NETs), but, unlike those reported in bacterial or fungal infection, NETs did not kill schistosome eggs in vitro. Together these show that S. japonicum eggs can induce the inflammatory phenotype of neutrophils, and further our understanding of the host–parasite interplay that takes place within the in vivo microenvironment of schistosome‐induced granuloma. These findings represent novel findings in a metazoan parasite, and confirm characteristics of NETs that have until now, only been observed in response to protozoan pathogens.     

Cytokines and their association with insulin resistance in obese pregnant women with different levels of physical activity

BackgroundCytokines contribute to insulin resistance in pregnancy, but the role of distinct cytokines is not fully understood.ObjectivesTo study whether cytokines produced by tissues other than skeletal muscle are associated with glucose and insulin metabolism activity in overweight and obese women and to study whether these associations can be modified by physical activity.MethodsA longitudinal study with 44 overweight and obese pregnant women was conducted. Changes in cytokines levels (IFN-γ, IP-10, IL1-α, MIP1-α, adiponectin and leptin) and ICAM1 from early (15 wk) to late (32 wk) pregnancy were determined. Physical activity was measured objectively with accelerometers. In linear regression models, the associations between (changes in) cytokine levels and fasting glucose, fasting insulin and HOMA-IR were studied.ResultsBoth IFN-γ and IP-10 levels increased from early to late pregnancy, and adiponectin levels decreased. IFN-γ and IP-10 were positively associated with fasting glucose, whereas IL-1α, ICAM1 and adiponectin were inversely associated with insulin and insulin resistance. The association of IL-1α with insulin and insulin resistance was only found in women with low levels of physical activity.ConclusionsIFN-γ, IP-10, IL1-α, ICAM1, and adiponectin may play a role in glucose and insulin metabolism in pregnancy. The relationship of IL-1α with insulin and insulin resistance might be moderated by levels of physical activity. Further studies are required to confirm the role of these cytokines in glucose and insulin metabolism in obese pregnant women.     

Resistin,Adiponectin, Ghrelin,Leptin, and Proinflammatory Cytokines: Relationships in Obesity

Objective: To evaluate interactions among leptin, adiponectin, resistin, ghrelin, and proinflammatory cytokines [tumor necrosis factor receptors (TNFRs), interleukin‐6 (IL‐6)] in nonmorbid and morbid obesity. Research Methods and Procedures: We measured these hormones by immunoenzyme or radiometric assays in 117 nonmorbid and 57 morbidly obese patients, and in a subgroup of 34 morbidly obese patients before and 6 months after gastric bypass surgery. Insulin resistance by homeostasis model assessment, lipid profile, and anthropometrical measurements were also performed in all patients. Results: Average plasma lipids in morbidly obese patients were elevated. IL‐6, leptin, adiponectin, and resistin were increased and ghrelin was decreased in morbidly obese compared with nonmorbidly obese subjects. After adjusting for age, gender, and BMI in nonmorbidly obese, adiponectin was positively associated with HDLc and gender and negatively with weight (β = ?0.38, p < 0.001). Leptin and resistin correlated positively with soluble tumor necrosis factor receptor (sTNFR) 1 (β = 0.24, p = 0.01 and β = 0.28, p = 0.007). In the morbidly obese patients, resistin and ghrelin were positively associated with sTNFR2 (β = 0.39, p = 0.008 and β = 0.39, p = 0.01). In the surgically treated morbidly obese group, body weight decreased significantly and was best predicted by resistin concentrations before surgery (β = 0.45, p = 0.024). Plasma lipids, insulin resistance, leptin, sTNFR1, and IL‐6 decreased and adiponectin and ghrelin increased significantly. Insulin resistance improved after weight loss and correlated with high adiponectin levels. Discussion: TNFα receptors were involved in the regulatory endocrine system of body adiposity independently of leptin and resistin axis in nonmorbidly obese patients. Our results suggest coordinated roles of adiponectin, resistin, and ghrelin in the modulation of the obesity proinflammatory environment and that resistin levels before surgery treatment are predictive of the extent of weight loss after bypass surgery.     

Adipokines,Ghrelin and Obesity‐Associated Insulin Resistance in Nondiabetic Patients with Acute Coronary Syndrome

Altered glucose metabolism negatively modulates outcome in acute coronary syndromes (ACS). Insulin resistance is commonly associated with increasing BMI in the general population and these associations may involve obesity‐related changes in circulating ghrelin and adipokines. We aimed at investigating interactions between BMI, insulin resistance and ACS and their associations with plasma ghrelin and adipokine concentrations. Homeostasis model assessment of insulin resistance (HOMA_IR)‐insulin resistance index, plasma adiponectin, leptin, total (T‐Ghrelin), acylated (Acyl‐Ghrelin), and desacylated ghrelin (Desacyl‐Ghrelin) were measured in 60 nondiabetic ACS patients and 44 subjects without ACS matched for age, sex, and BMI. Compared with non‐ACS, ACS patients had similar HOMA_IR and plasma adipokines, but lower T‐ and Desacyl‐Ghrelin and higher Acyl‐Ghrelin. Obesity (BMI > 30) was associated with higher HOMA_IR, lower adiponectin, and higher leptin (P < 0.05) similarly in ACS and non‐ACS subjects. In ACS (n = 60) HOMA_IR remained associated negatively with adiponectin and positively with leptin independently of BMI and c‐reactive protein (CRP) (P < 0.05). On the other hand, low T‐ and Desacyl‐Ghrelin with high Acyl‐Ghrelin characterized both obese and non‐obese ACS patients and were not associated with HOMA_IR. In conclusion, in ACS patients, obesity and obesity‐related changes in plasma leptin and adiponectin are associated with and likely contribute to negatively modulate insulin resistance. ACS per se does not however enhance the negative impact of obesity on insulin sensitivity. High acylated and low desacylated ghrelin characterize ACS patients independently of obesity, but are not associated with insulin sensitivity.     

Lifestyle variables, non-traditional cardiovascular risk factors, and the metabolic syndrome in an Aboriginal Canadian population

Objective : To examine lifestyle factors associated with metabolic syndrome (MetS) and to explore the relationships between MetS and non‐traditional cardiovascular disease risk factors [adiponectin, leptin, C‐reactive protein (CRP), interleukin‐6 (IL‐6), and serum amyloid A (SAA)] in an isolated Aboriginal Canadian community. Research Methods and Procedures : Data were obtained from 360 non‐diabetic adults participating in a population‐based study of Aboriginal Canadians. Fasting samples were drawn for glucose, insulin, lipids, adiponectin, leptin, CRP, IL‐6, and SAA. Percentage body fat was measured using bioelectrical impedance analysis. Past year physical activity and fitness level were assessed. MetS was diagnosed according to the criteria of the National Cholesterol Education Program, the World Health Organization, and the International Diabetes Federation. Results : The results showed that older age, higher percentage body fat, and lower fitness levels were associated with increased odds of MetS regardless of MetS definition and subject gender. Past year physical activity was independently related with the World Health Organization‐MetS in male subjects. Subjects with MetS had significantly higher leptin, CRP, IL‐6, and SAA levels and lower adiponectin levels; however, only adiponectin remained significantly low after adjustment for age and percentage body fat. Discussion : The study showed that higher percentage body fat and lower physical activity and fitness were associated with a higher prevalence of MetS in this Aboriginal community and that hypoadiponectinemia was independently associated with MetS.     

Effect of Lifestyle Modification on Adipokine Levels in Obese Subjects with Insulin Resistance

Objective: To study the effect of weight loss in response to a lifestyle modification program on the circulating levels of adipose tissue derived cytokines (adipokines) in obese individuals with insulin resistance. Research Methods and Procedures: Twenty‐four insulin‐resistant obese subjects with varying degrees of glucose tolerance completed a 6‐month program consisting of combined hypocaloric diet and moderate physical activity. Adipokines [leptin, adiponectin, resistin, tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6)] and highly sensitive C‐reactive protein were measured before and after the intervention. Insulin sensitivity index was evaluated by the frequently sampled intravenous glucose tolerance test. Results: Participants had a 6.9 ± 0.1 kg average weight loss, with a significant improvement in sensitivity index and reduction in plasma leptin (27.8 ± 3 vs. 23.6 ± 3 ng/mL, p = 0.01) and IL‐6 (2.75 ± 1.51 vs. 2.3 ± 0.91 pg/mL, p = 0.012). TNF‐α levels tended to decrease (2.3 ± 0.2 vs. 1.9 ± 0.1 pg/mL, p = 0.059). Adiponectin increased significantly only among diabetic subjects. The reductions in leptin were correlated with the decreases in BMI (r = 0.464, p < 0.05) and with changes in highly sensitive C‐reactive protein (r = 0.466, p < 0.05). Discussion: Weight reduction in obese individuals with insulin resistance was associated with a significant decrease in leptin and IL‐6 and a tendency toward a decrease in circulating TNF‐α, whereas adiponectin was increased only in diabetic subjects. Further studies are needed to elucidate the relationship between changes of adipokines and the health benefits of weight loss.     

Adipokines,inflammation, insulin resistance,and carotid atherosclerosis in patients with rheumatoid arthritis

Introduction

Cardiovascular (CV) morbidity and mortality are increased in patients with rheumatoid arthritis (RA). Inflammation is thought to be an important factor in accelerated atherosclerosis in RA, whereas insulin resistance is a known risk factor for atherosclerosis in RA. We hypothesised that adipokines could be a link between inflammation, insulin resistance, and atherosclerosis in RA.

Methods

The common carotid artery (CCA) intima-media thickness (IMT), CCA resistive index (RI), and carotid plaques were measured by ultrasonography in 192 patients with RA. Insulin resistance was assessed by the homeostasis model assessment for insulin resistance (HOMA-IR). Serum adiponectin, leptin, resistin, tumor necrosis factor-α, and interleukin (IL)-6 concentrations were determined.

Results

The CCA RI was associated with CCA IMT and the estimated total plaque volume after adjustment for conventional CV risk factors. Among adipokines, resistin and IL-6 were correlated with inflammatory parameters. Leptin and leptin:adiponectin (L:A) ratio were correlated with metabolic risk factors, including HOMA-IR. And L:A ratio was related to the CCA RI after adjustment for conventional and nonconventional CV risk factors, including HOMA-IR, erythrocyte sedimentation rate and C-reactive protein.

Conclusion

L:A ratio was associated with HOMA-IR and carotid RI. L:A ratio might be an independent factor for predicting cardiovascular risk in patients with RA.     

Corticotrophin-Releasing Factor (CRF) and the Urocortins Are Potent Regulators of the Inflammatory Phenotype of Human and Mouse White Adipocytes and the Differentiation of Mouse 3T3L1 Pre-Adipocytes

Chronic activation of innate immunity takes place in obesity and initiated by the hypertrophic adipocytes which obtain a pro-inflammatory phenotype. The corticotrophin-releasing factor (CRF) family of neuropeptides and their receptors (CRF₁ and CRF₂) affect stress response and innate immunity. Adipose tissue expresses a complete CRF system. The aim of this study was to examine the role of CRF neuropeptides in the immune phenotype of adipocytes assessed by their expression of the toll-like receptor-4 (TLR4), the production of inflammatory cytokines IL-6, TNF-α and IL-1β, chemokines IL-8, monocyte attractant protein-1 (MCP-1) and of the adipokines adiponectin, resistin and leptin. Our data are as follows: (a) CRF, UCN2 and UCN3 are expressed in human white adipocytes as well as CRFR_1a, CRFR_2a and CRFR_2b but not CRFR_2c. 3T3L1 pre-adipocytes and differentiated adipocytes expressed both CRF₁ and CRF₂ receptors and UCN3, while UCN2 was detected only in differentiated adipocytes. CRF₂ was up-regulated in mouse mature adipocytes. (b) CRF₁ agonists suppressed media- and LPS-induced pre-adipocyte differentiation while CRF₂ receptor agonists had no effect. (c) In mouse pre-adipocytes, CRF₂ agonists suppressed TLR4 expression and the production of IL-6, CXCL1 and adiponectin while CRF₁ agonists had no effect. (d) In mature mouse adipocytes LPS induced IL-6 and CXCL1 production and suppressed leptin. (e) In human visceral adipocytes LPS induced IL-6, TNF-α, IL-8, MCP-1 and leptin production and suppressed adiponectin and resistin. (f) In mouse mature adipocytes CRF₁ and CRF₂ agonists suppressed basal and LPS-induced production of inflammatory cytokines, TLR4 expression and adiponectin production, while in human visceral adipocytes CRF and UCN1 suppressed basal and LPS-induced IL-6, TNF-α, IL-8 and MCP-1 production. In conclusion, the effects of the activation of CRF₁ and CRF₂ may be significant in ameliorating the pro-inflammatory activity of adipocytes in obesity.     

Effect of the Interleukin‐6 (−174) G/C Promoter Polymorphism on Adiponectin and Insulin Sensitivity

We investigated the relation among the interleukin (IL)‐6 (?174) G/C promoter polymorphism, adipose tissue gene expression of IL6, circulating adiponectin, and systemic insulin sensitivity. Eighty‐five Swedish male subjects who had participated in our previous prediabetic phenotype characterization study were genotyped for the IL6 (?174) G/C polymorphism. Subcutaneous adipose tissue gene expression of IL6 and adiponectin was measured in 44 subjects. The IL6 (?174) G allele carriers had higher fasting plasma insulin levels (C/C, 7.8 ± 1.1; G/C, 9.0 ± 0.6; G/G, 10.5 ± 1.0 mU/L) and higher homeostasis model assessment for insulin resistance (C/C, 1.6 ± 0.2; G/C, 1.9 ± 0.1; G/G, 2.2 ± 0.2) compared with subjects with the C/C genotype. The circulating adiponectin levels were lower in the G allele carriers (C/C, 7.93 ± 0.45; G/C, 7.05 ± 0.44; G/G, 7.02 ± 0.46 μg/mL), whereas the IL‐6 levels did not differ among the three genotypes. Adipose tissue IL6 gene expression was significantly higher in the G allele carriers compared with the subjects homozygous for the C allele (C/C, 0.29 ± 0.15; G/C, 0.84 ± 0.29; G/G, 0.62 ± 0.35). Our results suggest that IL6 (?174) G/C polymorphism is associated with insulin resistance and increased adipose tissue IL6 gene expression, which can impair adiponectin production.     

Effect of Pregnancy on Anti-HEV Antibody Titres,Plasma Cytokines and the Corresponding Gene Expression Levels in the PBMCs of Patients Presenting with Self-Recovering Clinical and Subclinical Hepatitis E

High mortality in pregnant women (PR) is a characteristic of hepatitis E in developing countries. To understand the pathogenesis of HEV infection in self-limiting disease during pregnancy, we compared clinical (PR-patients) and subclinical-HEV-infections in pregnant women in the first (SC-PR-1) and later (2nd and 3rd, SC-PR-2+3) trimesters with the respective healthy controls and acute non-PR patients. The SC-PR-2+3 exhibited lower ALT, bilirubin levels, anti-HEV-IgM/IgG titres than the acute-PR/non-PR-patients (p<0.05–0.0001). IFNγ/IL4ratios indicated Th2/Th1 bias in non-PR and PR-patients respectively. Raised levels of 10/20 plasma cytokines in the non-PR-patients reflect predominant inflammatory response, unaltered- IFNγ/reduced-IFNα responses and a robust chemokine secretion. On contrary, the acute-PR-patients exhibited drastic reduction in majority of the cytokines relative to in the non-PR-patients. Importantly, diminished or unaltered response was noted in the acute-PR-group when compared to the corresponding controls. The only exception was sIL2RA, increasing in both patient categories. Of the 14 genes evaluated, the expression of IFNγ/IL10/IL1A/IL7/CCL2/CCL3/CXCL8/CXCL10 was higher in the non-PR patients. Of these, the expression of IFNγ/IL10/IL1A/CCL2/CCL3/CXCL8 and, additionally, IL2/IL6/TNF genes was higher in the clinical-PRs. Almost identical pattern was noted in the control-PR-2+3 category indicating no influence of HEV infection. Comparison of patient-categories identified significant elevation of IFNγ(P<0.001), CCL2(p<0.01), CXCL8(P<0.05), IL1B(p<0.05) and IL10(P<0.0001) and decrease in CXCL10(<0.05) in the PR-patients. The results suggest antibody-dependent disease severity and impaired immune response in the PR patients. Higher expression of cytokine-genes in the PBMCs did not correlate with the plasma-cytokine levels in the PR-patients.     

Leptin up-regulates pro-inflammatory cytokines in discrete cells within mouse colon

Dysregulation of leptin associated with obesity is implicated in obesity-related colon cancer, but mechanisms are elusive. Increased adiposity and elevated plasma leptin are associated with perturbed metabolism in colon and leptin receptors are expressed on colon epithelium. We hypothesise that obesity increases the sensitivity of the colon to cancer by disrupting leptin-regulated gene targets within colon tissues. PCR arrays were used to firstly identify leptin responsive genes and secondly to identify responses to leptin challenge in wild-type mice, or those lacking leptin (ob/ob). Leptin-regulated genes were localised in the colon using in situ hybridisation. IL6, IL1β and CXCL1 were up-regulated by leptin and localised to discrete cells in gut epithelium, lamina propria, muscularis and at the peritoneal serosal surface. Leptin regulates pro-inflammatory genes such as IL6, IL1β and CXCL1, and might increase the risk of colon cancer among obese individuals.     

Interleukin 21 Controls mRNA and MicroRNA Expression in CD40-Activated Chronic Lymphocytic Leukemia Cells

Several factors support CLL cell survival in the microenvironment. Under different experimental conditions, IL21 can either induce apoptosis or promote CLL cell survival. To investigate mechanisms involved in the effects of IL21, we studied the ability of IL21 to modulate gene and miRNA expressions in CD40-activated CLL cells. IL21 was a major regulator of chemokine production in CLL cells and it modulated the expression of genes involved in cell movement, metabolism, survival and apoptosis. In particular, IL21 down-regulated the expression of the chemokine genes CCL4, CCL3, CCL3L1, CCL17, and CCL2, while it up-regulated the Th1-related CXCL9 and CXCL10. In addition, IL21 down-regulated the expression of genes encoding signaling molecules, such as CD40, DDR1 and PIK3CD. IL21 modulated a similar set of genes in CLL and normal B-cells (e.g. chemokine genes), whereas other genes, including MYC, TNF, E2F1, EGR2 and GAS-6, were regulated only in CLL cells. An integrated analysis of the miRNome and gene expression indicated that several miRNAs were under IL21 control and these could, in turn, influence the expression of potential target genes. We focused on hsa-miR-663b predicted to down-regulate several relevant genes. Transfection of hsa-miR-663b or its specific antagonist showed that this miRNA regulated CCL17, DDR1, PIK3CD and CD40 gene expression. Our data indicated that IL21 modulates the expression of genes mediating the crosstalk between CLL cells and their microenvironment and miRNAs may take part in this process.