Chemerin mRNA Research Articles

The expression of chemerin and the influence of sitagliptin on its expression in non-alcoholic fatty liver disease rats complicated with prediabetes

Objective: To study the role of chemerin in the development and progression of non-alcoholic fatty liver disease (NAFLD) rats complicated with prediabetes and explore the effect of sitagliptin on the expression of chemerin. Methods: The model of NAFLD and prediabetic rats was established. The rats were then randomly divided into normal group, model group and intervention group. Sitagliptin intervention was performed for 8 weeks after 8 weeks's feeding with high-fat diet. After that, the level of blood glucose, insulin and chemerin was measured. Cytological changes of liver, omentum and epididymal adipose tissue were observed by HE staining. The distribution of chemerin in the tissues was observed by immunohistochemistry. The mRNA and protein expression of chemerin and chemokine-like receptor 1 (chemR23) in liver and adipose tissue were detected by RT-PCR and Western blotting. Results: After 8 weeks of sitagliptin treatment, compared with the normal group(n=8), serum chemerin in the model group (n=6) increased[(35.19±3.86) ng/L vs (29.90±2.17) ng/L, P=0.046)]. Serum chemerin in the intervention group (n=6) was lower than that of the normal group[(23.20±1.89) ng/L vs (29.90±2.17) ng/L, P=0.013)]. Compared with the normal group, the mRNA and protein expression of chemerin in the liver and omentum adipose tissue of the model group increased (P<0.05). The expression amount of the omental adipose tissue was more than that of the liver(P<0.05). The mRNA expression of chemR23 both in liver and omental adipose tissue increased (P<0.05), and the expression amount of the liver was more than that of omental adipose tissue. The levels of fasting blood glucose[(5.72 ±1.36)mmol/L vs(3.77±0.77)mmol/L, P=0.002], total cholesterol[(1.53±0.09)mmol/L vs (1.23±0.17)mmol/L, P=0.032], aspartate aminotransferase[(319.8±104.4)U/L vs (195.0±25.0) U/L, P=0.016]in the model group were significantly higher than those in the normal group. The differences between the intervention group and the normal group was not significant. But the level of fasting blood glucose[(4.33±0.39)mmol/L vs (5.72±1.36)mmol/L, P=0.019], total cholesterol[(1.23±0.17)mmol/L vs (1.53±0.09)mmol/L, P=0.047]and aspartate aminotransferase[(198.4±22.8)U/L vs (319.8±104.4)U/L, P=0.014)]of the intervention group was significantly lower than those of the model group. Conclusions: Increasing expression of serum chemerin is consistent with hepatic steatosis, suggesting that chemerin can serve as a serological warning indicator for NAFLD complicated with pre-diabetes. Sitagliptin affects the mRNA and protein expression of chemerin and its receptor chemR23 in steatosis liver. This may provide a research direction for the pathophysiology and treatment of NAFLD.

Whole-Body but Not Hepatic Knockdown of Chemerin by Antisense Oligonucleotide Decreases Blood Pressure in Rats.

Chemerin is an inflammatory adipokine positively associated with hypertension and obesity. The majority of chemerin derives from the liver and adipose tissue, however, their individual contributions to blood pressure are unknown. We began studying chemerin in the normal rat using antisense oligonucleotides (ASO) with whole-body activity (Gen 2.5 chemerin ASO) or liver-restricted activity (GalNAc chemerin ASO). We hypothesized that in normotensive male Sprague-Dawley rats, circulating chemerin is predominately liver-derived and regulates blood pressure. A dosing study of the Gen 2.5 chemerin ASO (with a scrambled control ASO) supported 25 mg/kg as the appropriate dose. GalNAc chemerin ASO was also assessed and used at 10 mg/kg. Radiotelemetry monitored mean arterial pressure (MAP) for a 1-week baseline and weekly subcutaneous ASO injections for 4 weeks. Two days after the final injection, animals were euthanized for tissue reverse transcription-polymerase chain reaction and chemerin Western analysis. Gen 2.5 chemerin ASO treatments reduced chemerin mRNA and protein in liver, retroperitoneal fat (RP), and mesenteric perivascular adipose tissue (mPVAT), as well as reducing protein in plasma. GalNAc chemerin ASO treatments reduced chemerin mRNA and protein in liver and chemerin protein in plasma but had no effect on expression in RP fat or mPVAT. Gen 2.5 chemerin ASO treatment reduced MAP compared with control ASO but was unchanged in animals receiving the GalNAc chemerin ASO. Although circulating chemerin is liver-derived, it does not play a major role in blood pressure regulation. Local effects of chemerin from fat may explain this discrepancy and support chemerin's association with hypertension and obesity.

Circulating adipokines and mRNA expression in adipose tissue and the placenta in women with gestational diabetes mellitus

Maternal adipose tissue and the placenta secrete various molecules commonly called adipokines such as chemerin, omentin-1, visfatin, adiponectin, and leptin that are important players in the pathogenesis of insulin resistance. Gestational diabetes mellitus (GDM) is defined as a state of glucose intolerance characterized by β-cell dysfunction and insulin resistance. To examine whether circulating adipokines and their mRNA expression in the adipose tissue and the placenta are altered in GDM pregnancy, we compared 15 GDM women [obese (BMI > 30) and non-obese (BMI < 30)] to 23 NGT (normal glucose tolerance) women [obese and non-obese], at the time of the Cesarean section. Circulating chemerin and leptin were higher (p = 0.009 and p = 0.005, respectively) and circulating omentin-1, visfatin, as well as the adiponectin/leptin ratio were lower (p = 0.039, p = 0.007 and p = 0.011, respectively) in GDM-obese compared to NGT-non-obese women. Chemerin and leptin correlated positively with BMI and HOMA-IR and omentin-1 correlated negatively with BMI. Serum TNF-α was significantly elevated in all obese compared to non-obese pregnant women and correlated positively with BMI. Adiponectin levels were reduced -although not significantly- in GDM- and NGT-obese women compared to their non-obese counterparts. Resistin, RPB4 and IL-6 levels did not differ significantly between groups. Chemerin mRNA expression in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) was significantly higher compared to placenta in all women (6-to 24-times, p < 0.05). Chemerin-VAT mRNA expression in GDM-obese tended to be significantly higher compared to NGT-non-obese women (3-times, p = 0.005). Omentin-1 mRNA expression was significantly higher in VAT compared to SAT (50- to 100-times, p < 0.01) and its expression in placenta was negligible in all women. Although, leptin was expressed significantly higher in SAT compared to VAT and the placenta in all women (5- to 46-times, p < 0.05), only its mRNA expression in VAT of obese (GDM and NGT) differed significantly when compared to NGT-non-obese women (3-times higher, p < 0.02). Visfatin mRNA expression was comparable in all tissues. In conclusion, chemerin and leptin are elevated and omentin-1 and visfatin levels are decreased in GDM women complicated by obesity. This finding together with the positive association of chemerin and leptin with markers of insulin resistance, suggests that these adipokines and more especially chemerin and leptin accompanied by their adipose tissue expression could contribute to the increased insulin resistance and low grade inflammation that characterizes GDM-obese women.

Alleviation of Diet-Induced Fat Accumulation by a Small Molecule CMKLR1 Antagonist in Mice

Objective: Non-alcoholic Fatty Liver Disease (NAFLD) is believed to be correlated with chemerin and its receptor, Chemokine-like Receptor 1 (CMKLR1). We analyse the role of CMKLR1 in NAFLD by using a novel small molecule CMKLR1 antagonist-NETA (2-naphthoyl ethyl trimethyl ammonium) in vitro and in vivo. Methods: We assessed the effects of -NETA on a mouse model of high-fat-diet-induced fat accumulation in liver and adipose tissue and an analogous cell model established by culturing Hepa 1-6 and 3T3-L1 cells. Results: We found that chemerin and CMKLR1 mRNA were significantly increased in the livers and fat tissue of the mice fed the high fat diet relative to those in mice fed the normal diet. α-NETA administration suppressed serum TC, TG, AST and ALT levels and hepatic TG content as well as inhibited lipid metabolism-associated factors in the livers and fat of high fat diet mice. Furthermore, in the cell model, α-NETA suppressed oleic acid induction of Hepa 1-6 cell steatosis, 3T3-L1 adipogenesis and the expression of mRNAs for related lipid metabolism-associated factors. Conclusions: Chemerin/CMKLR1 signaling plays an important role in the progression of NAFLD.

Effects of Aldosterone on Chemerin Expression And Secretion in 3T3-L1 Adipocytes.

Aldosterone plays a pivotal role in the pathogenesis of metabolic syndrome and cardiovascular disease; however, the underlying mechanisms have not been clarified. Chemerin has been characterized as an adipokine with crucial roles in obesity-associated disorders and cardiovascular homeostasis. The aim of the present study was to investigate the direct effects of aldosterone on chemerin expression and secretion in 3T3-L1 adipocytes and to identify the potential signalling pathways involved. Chemerin mRNA levels were measured using real-time PCR, whereas the levels of secreted chemerin in the culture media were determined using ELISA. Treatment with aldosterone induced time- and dose-dependent increases of chemerin gene expression and protein secretion, and effect that was mediated through the mineralocorticoid receptor. Signalling studies suggested that the NF-κB pathway is involved in aldosterone-induced chemerin expression. Taken together, our data demonstrate a direct interaction between aldosterone and chemerin in adipocytes, which may be an underlying mechanism linking aldosterone-associated metabolic abnormalities and cardiovascular disease.

Abstract P102: Liver Acquitted, Fat Indicted: Hepatic Chemerin Knockdown Does Not Reduce Blood Pressure While Whole-body Knockdown Does

Chemerin is an inflammatory adipokine positively associated with hypertension and obesity with the majority of chemerin thought to derive from the liver and adipose tissue. The contributions of liver-derived chemerin to plasma chemerin levels and blood pressure regulation are unknown. We compared whole-body vs liver chemerin inhibition using antisense oligonucleotides (ASO) with liver-restricted activity (GalNAc) or liver and fat activity (Gen 2.5). We hypothesized that in normotensive male SD rats, circulating chemerin is predominately liver-derived and regulates blood pressure. A scrambled ASO control and phosphate-buffered saline (PBS) were used as controls and radiotelemetry was used to monitor blood pressure. Baseline mean arterial blood pressure (MAP) was recorded for one week, beginning 5 days after surgery to establish a baseline. ASOs were given weekly by subcutaneous injections for four weeks. Two days after the final injection, animals were sacrificed for tissue RT-PCR and plasma chemerin measurements using Western analysis. Gen 2.5 chemerin ASO treatments (compared to PBS control) reduced chemerin mRNA in liver, retroperitoneal fat, and mesenteric perivascular adipose tissue (mPVAT) by 99.5% ± 0.1%, 95.2% ± 0.3%, and 69% ± 2%, respectively, and plasma chemerin was reduced to undetectable levels. GalNAc chemerin ASO treatments (compared to PBS control) reduced chemerin mRNA in liver by 97.9% but had no effect on chemerin expression in retroperitoneal fat and mPVAT; plasma chemerin was reduced by 90% ± 5%. Gen 2.5 chemerin ASO treatment reduced MAP, which reached a nadir of 7 ± 2.1 mmHg 48 – 72 hours after each dose compared to the scrambled ASO controls. By contrast, MAP was unchanged in animals receiving the GalNAc chemerin ASO. Thus, although most circulating chemerin is liver-derived, plasma chemerin does not play a role in blood pressure regulation. This study suggests that while chemerin is still generally associated with increased blood pressure, circulating chemerin levels cannot directly predict this effect. In addition, local effects of chemerin from fat may explain this discrepancy and support chemerin’s association with both hypertension and obesity.

Effects of aerobic exercise and dieting on chemerin and its receptor CMKLR1 in the livers of type 2 diabetic rats

To investigate the effects of aerobic exercise and dieting on chemerin and its receptor chemokine like receptor-1 (CMKLR1) in the livers of type 2 diabetes mellitus (DM) rats and its possible roles on the improvements of blood glucose and lipid metabolism. Fifty male SD rats were randomly divided into control group (Con, n=6) fed with normal diet and DM model group (n=44) fed with high fat diet. After 8-week feeding, DM model rats were intraperitoneal injected streptozocin (STZ) at the dose of 30 mg/kg body weight to establish DM rats. The successfully established diabetes rats were randomly divided into 4 groups (n=6):diabetes control group (DM), diabetes exercise group (EDM), diabetes dieting group by feeding normal diet (NDM) and diabetes exercise plus dieting group (ENDM). During the following 4 weeks, exercise rats participated in moderate intensity aerobic exercise on a treadmill with a progressing increasing load for 4 weeks. Fasting blood glucose (FBG) was determined by Roche glucometer. Serum levels of triglyceride (TG), total cholesterol (TC) and low-density lipoprotein (LDL)) were detected by using full automatic biochemical analyzer. The mRNA and protein expressions of chemerin and CMKLR1 in the livers were detected by real time PCR and Western blot, respectively. Accompanied with the increased serum levels of TC, TG, LDL and FBG in DM rats, the mRNA and protein levels of chemerinand CMKLR1 in the livers of DM rats were significant up-regulated. The serum levels of TC, TG, LDL and FBG were reduced in EDM, NDM and ENDM rats compared with those of DM rats, meanwhile,decreased protein levels of chemerin were found in the livers of EDM, NDM and ENDM rats with most significant in ENDM rats while increased protein levels of CMKLR1 in the livers of NDM and ENDM rats. Four weeks of aerobic exercise with or without dieting decreased chemerin and increased CMKLR1 in the livers of DM rats at the protein levels, which might be attributed to the improvement of blood glucose and lipid metabolism of DM rats.

Hepatic chemerin mRNA in morbidly obese patients with nonalcoholic fatty liver disease.

The aim of this study was to investigate hepatic chemerin mRNA, serum chemerin concentration, and immunohistochemical staining for chemerin and and chemokine receptor-like 1 (CMKLR1) in hepatic tissue in 56 morbidly obese women with nonalcoholic fatty liver disease (NAFLD) and to search for a relationship with metabolic and histopathological features. Chemerin mRNA was assessed by quantitative real-time PCR, chemerin, and CMKLR1 immunohistochemical expression with specific antibodies, while serum chemerin concentration was assessed with commercially available enzyme-linked immunosorbent assays. Serum chemerin concentration reached 874.1 ±234.6 ng/ml. There was no difference in serum chemerin levels between patients with BMI < 40 kg/m2 and ≥ 40 kg/m2. Serum chemerin concentration tended to be higher in patients with hepatocyte ballooning, greater extent of steatosis, and definite nonalcoholic steatohepatitis (NASH). Liver chemerin mRNA was observed in all included patients and was markedly, but insignificantly, higher in those with BMI ≥ 40 kg/m2, hepatocyte ballooning, greater extent of steatosis, and definite NASH. Hepatic chemerin mRNA might be a predictor of hepatic steatosis, hepatocyte ballooning, and NAFLD activity score (NAS) but seemed not to be a primary driver regulating liver necroinflammatory activity and fibrosis. The lack of association between serum chemerin and hepatic chemerin mRNA may suggest that adipose tissue but not the liver is the main source of chemerin in morbidly obese women.

Hepatic chemerin mRNA expression is reduced in human nonalcoholic steatohepatitis.

Chemerin is associated with insulin resistance and is expressed in the liver. Nonalcoholic fatty liver disease (NAFLD) is related to impaired insulin sensitivity, but studies evaluating hepatic and serum chemerin in NAFLD resulted in discordant data. Chemerin mRNA was determined in the liver tissue obtained from 33 controls and 76 NAFLD patients. Chemerin serum levels were measured in a different cohort of patients with ultrasound-diagnosed NAFLD and the respective controls. Hepatic stellate cells and hepatocytes were exposed to selected metabolites and nuclear receptor agonists to study the regulation of chemerin. Effect of recombinant chemerin on hepatocyte released proteins was analysed. Hepatic chemerin expression was not related to BMI, gender, type 2 diabetes and hypertension. Chemerin mRNA did not correlate with steatosis and was negatively associated with inflammation, fibrosis and nonalcoholic steatohepatitis (NASH) score. Patients with NASH had lower chemerin mRNA compared to those with borderline NASH and controls. Factors with a role in NASH mostly did not regulate chemerin in the liver cells. Of note, liver X receptor agonist reduced chemerin protein. Serum chemerin was not changed in NAFLD. Levels positively correlated with age, waist-to-hip ratio, systolic blood pressure, serum FGF21 and lipocalin 2, and negatively with transferrin saturation. Chemerin induced FGF21 in supernatants of primary human hepatocytes. Hepcidin, a major regulator of iron homoeostasis and lipocalin 2, were not regulated by chemerin. Chemerin mRNA is reduced in the liver of NASH patients, and liver X receptor seems to have a role herein.

Plasmacytoid dendritic cells as a key player in the initiation phase of alopecia areata-induced C3H/HeJ mouse

Recently, the pathomechanism of alopecia areata (AA) has been thought to be a tissue-specific autoimmune disease. So far, interferon (IFN)-γ has been regarded as the most important key cytokine that may induce the collapse of HF immune privilege, apotosis and the upregulation of CXCL 10 in C3H/HeJ AA mouse. In this study, we focus on the role of type I IFN, IFN-α, in the initiation of AA. We previously reported seven cases of AA, including both new onset and recurrent AA, following swine flu viral infection. In this study, we generate AA-induced C3H/HeJ mouse by intra-dermal injection of activated lymphonode cells with IL-2, IL-7 and IL-15. Immunohistochemical staining revealed that IFN-α producing plasmacytoid dendritic cells (pDCs) densely distributed around HFs in not only lesion skin but also non-lesional skin obtained from AA induced-C3H/HeJ mice. Flowcytometric analysis showed the increased frequency of pDCs in skin-infiltrated cells of non-lesional skin from C3H/HeJ mice with AA. Real-time PCR also showed higher expression of IFN-α2, IFN-α4 and chemerin mRNA in C3H/HeJ mouse with AA. In vitro study, IFN-α inhibited the hair elongation of cultured murine vibrissae in Willium's E medium by Philpott's model. In addition, H-2k and CXCL10 expression were upregulated in cultured murine vibrissae by IFN-α. Imiquimod (IMQ) is the potent inducer of IFN-α via TLR7/9 on pDCs. IMQ applied C3H/HeJ mouse showed retardation of hair cycle stage compared to control mouse with infiltration of SiglecH + pDCs with IFN-α expression by immunohistochemical staining. Finally, we succeeded the induction of AA only by intra-dermal injection of pDCs in C3H/HeJ mouse. In conclusion, pDCs may play an important role for the initiation of AA by over expression of IFN-α via pDCs.

Association of Chemerin and Vascular Endothelial Growth Factor (VEGF) with Diabetic Nephropathy.

BackgroundDiabetic nephropathy (DN) is a common complication of diabetes, caused by diabetic microvascular lesions. The pathogenesis of DN is complicated, involving genetics, physics, chemistry, and environmental factors. Chemerin is a fat cell factor that participates in regulating inflammation. Vascular endothelial growth factor (VEGF) promotes vascular endothelial cell proliferation, differentiation, and angiogenesis. The relationship role of Chemerin and VEGF in DN is not fully understood.Material/MethodsSD rats were randomly divided into 2 groups: the control group and the DN group. Streptozotocin was used to construct the DN model. Serum creatinine (Scr), blood urea nitrogen (BUN), and urine microalbumin (UAlb) were detected. Real-time PCR and Western blot were used to test Chemerin and VEGF mRNA and protein expression in kidney tissue. ELISA was performed to test TGF-β1, TNF-α, and INF-γ levels. The correlation of Chemerin and VEGF with renal function and inflammatory factors was analyzed.ResultsDN group rats showed obviously increased Scr and BUN levels, and elevated TGF-β1, TNF-α, and INF-γ secretion (P<0.05). Compared with controls, Chemerin and VEGF were clearly overexpressed in the DN group (P<0.05). Chemerin and VEGF expression were positively correlated with inflammatory factors and renal function.ConclusionsChemerin and VEGF play important roles in DN by regulating inflammatory factors and renal function. They may be treated as indicators of DN.

Effects of alpha-lipoic acid on chemerin secretion in 3T3-L1 and human adipocytes

Chemerin is a novel adipokine associated with obesity and insulin resistance. α-Lipoic acid (α-LA) has shown beneficial properties on diabetes and obesity. The aim of this study was to examine the effects of α-LA on chemerin production in adipocytes in absence or presence of TNF-α, insulin and AICAR. The potential signaling pathways involved in α-LA effects on chemerin were also analyzed. α-LA actions on chemerin were tested in differentiated 3T3-L1 adipocytes and in some cases in human subcutaneous and omental adipocytes. Chemerin mRNA levels were measured by RT-PCR and the amount of chemerin secreted to culture media was determined by ELISA. α-LA induced a concentration-dependent inhibition on both chemerin secretion and mRNA levels in 3T3-L1 adipocytes. The AMPK activator AICAR and the PI3K inhibitor LY294002 dramatically abrogated both chemerin secretion and gene expression, and further potentiated the inhibitory effect of α-LA on chemerin secretion. Insulin was able to partially reverse the inhibitory action of α-LA on chemerin secretion. α-LA also reduced basal chemerin secretion in both subcutaneous and omental adipocytes from overweight/obese subjects. Moreover, α-LA was able to abolish the stimulatory effects of the pro-inflammatory cytokine TNF-α on chemerin secretion. Our data demonstrated the ability of α-LA to inhibit chemerin production, an adipokine associated to obesity and metabolic syndrome, suggesting that the reduction of chemerin could contribute to the antiobesity/antidiabetic properties described for α-LA.

Circulating serum chemerin levels are elevated in lipodystrophy.

Lipodystrophy (LD) is characterized by loss of adipose tissue, dysregulation of adipokines and severe metabolic complications. Regulation of the insulin resistance-inducing and proinflammatory adipokine chemerin has not been assessed in LD. Therefore, we determined chemerin serum levels in LD, chemerin mRNA expression in insulin-sensitive tissues of LD mice, as well as the impact of metreleptin treatment on circulating chemerin in LD patients. Serum chemerin, as well as clinical and biochemical parameters of glucose metabolism, lipid metabolism, and inflammation, was measured in 37 LD patients and 37 age-, gender- and body mass index-matched controls. Furthermore, chemerin mRNA expression was determined in LD mice and controls. Moreover, circulating chemerin was assessed at five different time points in 10 LD patients treated with metreleptin over 1year. Median serum chemerin levels were significantly higher in 37 subjects with LD (234·3μg/l) as compared to controls (204·0μg/l) (P=0·002). Multiple linear regression analysis showed that circulating chemerin was independently and positively associated with glycosylated haemoglobin A1c (HbA1c) and C-reactive protein (CRP). Chemerin mRNA expression was significantly increased 2·5-fold in visceral adipose tissue (VAT) and 5·3-fold in brown adipose tissue (BAT) of LD mice as compared to controls (P<0·01). Circulating chemerin was not significantly altered by metreleptin treatment. Circulating levels of the adipokine chemerin are elevated in LD, as well as independently and positively associated with HbA1c and CRP. Increased chemerin might originate from VAT and BAT.

Chemerin Expression in the Peritoneal Fluid, Serum, and Ovarian Endometrioma of Women with Endometriosis.

Inflammation is an essential process in the pathogenesis of endometriosis. Serum and peritoneal fluid (PF) samples were collected from women with endometriosis (n = 31) and women without endometriosis (n = 48). Chemerin, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) levels in serum and PF samples were determined with a specific enzyme-linked immunosorbent assay. Eutopic endometrial tissue from controls and ovarian endometriotic cysts were obtained during surgery. Expression of chemerin and chemerin receptors in ectopic and eutopic endometrial tissues was measured on real-time reverse transcriptase-polymerase chain reaction. Protein expression was examined with Western blot and densitometric analysis. Chemerin concentrations were higher in PF from women with endometriosis than that in that from controls. PF chemerin concentrations were significantly correlated with both TNF-α and IL-6 levels in PF. The mRNA and protein of chemerin and its receptor were significantly increased in the ovarian endometrioma tissue compared with eutopic endometrium of controls. These findings suggest that chemerin plays a role in endometriosis-related pelvic inflammation.

High serum chemerin level in CKD patients is related to kidney function, but not to its adipose tissue overproduction

Chemerin is an adipokine modulating inflammatory response and affecting glucose and lipid metabolism. These disturbances are common in CKD. The aim of the study was: (a) to evaluate circulating chemerin level at different stages of CKD; (b) to measure subcutaneous adipose tissue chemerin gene expression; (c) to estimate the efficiency of renal replacement therapy in serum chemerin removal. 187 patients were included into the study: a) 58 patients with CKD; (b) 29 patients on hemodialysis; (c) 20 patients after kidney transplantation. 80 subjects constituted control group. Serum chemerin concentration was estimated by ELISA. The adipose tissue chemerin mRNA level was measured by RT-qPCR. The mean serum chemerin concentration in CKD patients was 70% higher than in the control group (122.9 ± 33.7 vs. 72.6 ± 20.7 ng/mL; p < 0.001) and it negatively correlated with eGFR (r = −0.71, p < 0.001). The equally high plasma chemerin level was found in HD patients and a HD session decreased it markedly (115.7 ± 17.6 vs. 101.5 ± 16.4 ng/mL; p < 0.001). Only successful kidney transplantation allowed it to get down to the values noted in controls (74.8 ± 16.0 vs. 72.6 ± 20.7 ng/mL; n.s.). The level of subcutaneous adipose tissue chemerin mRNA in CKD patients was not different than in patients of the control group. The study demonstrates that elevated serum chemerin concentration in CKD patients: (a) is related to kidney function, but not to increased chemerin production by subcutaneous adipose tissue, and (b) it can be efficiently corrected by hemodialysis treatment and normalized by kidney transplantation.

The Adipokine Chemerin Induces Apoptosis in Cardiomyocytes

Background: The adipokine chemerin has been associated with cardiovascular disease. We investigated the effects of chemerin on viability and intracellular signalling in murine cardiomyocytes, and the effects of insulin and TNF-α on cardiomyocyte chemerin production. Methods: Hoechst dye vital staining and cell cycle analysis were used to analyse the viability of murine cardiac cells in culture. Western blot was used to explore the phosphorylation of AKT and caspase-9 activity in neonatal rat cardiomyocytes and HL-1 cells. Finally, RT-qPCR, ELISA and western blot were performed to examine chemerin and CMKLR1 expression after insulin and TNF-α treatment in cardiac cells. Results: Chemerin treatment increased apoptosis, reduced phosphorylation of AKT at Thr308 and increased caspase-9 activity in murine cardiomyocytes. Insulin treatment lowered chemerin and CMKLR1 mRNA and protein levels, and the amount of chemerin in the cell media, while TNF-α treatment increased chemerin mRNA and protein levels but decreased expression of the CMKLR1 gene. Conclusion: Chemerin induces apoptosis, reduces AKT phosphorylation and increases the cleavage of caspase-9 in murine cardiomyocytes. The expression of chemerin is regulated by important metabolic (insulin) and inflammatory (TNF-α) mediators at cardiac level. Our results suggest that chemerin could play a role in the physiopathology of cardiac diseases.

Protective effect of liraglutide against ER stress in the liver of high-fat diet-induced insulin-resistant rats.

The purpose of this study was to investigate whether the glucagon-like peptide-1 (GLP-1) analog liraglutide can alleviate endoplasmic reticulum (ER) stress and insulin resistance (IR) in the liver of high-fat diet-induced insulin-resistant rats. Eighty-five male Sprague-Dawley rats were fed with normal chow or a high-fat diet for 12 weeks. The IR was evaluated using the hyperinsulinemic-euglycemic clamp technique. The rats in the HF group were further divided into four groups and were treated with or without liraglutide by subcutaneous injection. Body weight (BW), fasting blood glucose (FBG), fasting insulin (FINS), and insulin sensitivity were measured. The expression of ER stress marker GRP78 and its signaling mediators, such as IRE1α, PERK, and ATF6, in the liver were examined. The ultrastructure of the ER in the liver was examined by transmission electron microscopy. The expression levels of chemerin in the liver and the serum were also measured. After 4 weeks of liraglutide treatment, the BW, FBG, and FINS levels were significantly reduced, and the insulin sensitivity was increased compared with the HF only rats. Liraglutide reduced the expression of GRP78 and chemerin in liver tissue at both the mRNA and protein levels. Interestingly, the chemerin mRNA was closely correlated with the level of GRP78 mRNA, while the level of chemerin in serum was also associated with the FINS level. As a representative GLP-1 analog, liraglutide can suppress ER stress and reduce chemerin expression in the liver of rats exposed to a high-fat diet.

Chemerin expression in Chinese pregnant women with and without gestational diabetes mellitus

ObjectivesThe aim of this study was to determine the effect of obesity, gestational diabetes mellitus (GDM) on circulating chemerin concentrations and chemerin gene expression of adipotissue in pregnancy women. Material and methodsTotally 42 normal glucose tolerant (NGT) women and 48 women with GDM were included in this study. Their clinical features and biochemical parameters were analyzed. The NGT and GDM women were subgrouped by prepregnancy BMI as normal-weight group, overweight group, and obese group, respectively. Serum chemerin and tumor necrosis factor α (TNF-α) of these individuals were determined by ELISA methods, and subcutaneous adipose tissues’ mRNA expressions of chemerin and CMKLR1 (encoding the receptor of chemerin) were analyzed by real-time PCR. ResultsSerum chemerin in obese-NGT group and normal-weight-GDM group was significantly higher than that of normal-weight-NGT group. Chemerin and CMKLR1 mRNA expression of subcutaneous adipose tissue was lower in the obese-NGT group than normal-weight-NGT group. There was no significant difference of CMKLR1 mRNA expression between normal-weight-NGT and normal-weight-GDM group. Serum chemerin significantly and positively correlated with triglycerides (TG) and homeostasis model assessment of insulin resistance (HOMA-IR) assessed both by uni- and multivariate. ConclusionsGestational obesity, GDM may contribute to the elevating serum chemerin. Serum chemerin in pregnancy was associated with insulin resistance and triglycerides. Chemerin gene may play a role both in obese and GDM patients. CMKLR1 might exert its action only in obese individuals, not in GDM patients before delivery.

Abstract 564: Reduction of Blood Pressure with Antisense Oligodeoxynucleotides Against Chemerin

Chemerin promotes dendritic cells and macrophage migration to sites of inflammation. The liver and adipose tissues are sources of chemerin. There is a direct relationship of BMI, plasma chemerin concentration and blood pressure. Chemerin causes arterial contraction that is amplified in tissues with endothelial dysfunction. We hypothesized that if chemerin supported hypertension through such mechanisms, removal of chemerin should decrease blood pressure. Ten antisense oligodeoxynucleotides (ASOs) were developed against the retinoic acid receptor responder protein 2 (RARRES2, chemerin gene). ASO642647 was chosen as a lead based on excellent tolerance and minimal changes in a standard clinical panel. The model chosen was the deoxycorticosterone acetate (DOCA) salt hypertensive rat as this model shows profound endothelial dysfunction. Rats were uninephrectomized, given DOCA (s.c., 150 mg/kg) and placed on 1.0% NaCl + 0.2 % KCl. One week later, radiotelemeters were implanted for measurement of systolic, diastolic, mean arterial blood pressure and heart rate. ASOs (control nonsense or chemerin) were injected ip weekly over 3.5 weeks (25 mg/kg week 1 and 2; 12.5 mg/kg week 3 and 4) when DOCA-salt hypertension was stable (week 3.5). A group of DOCA-salt rats also received injections of PBS (ASO vehicle). Two days after the 4th injection, tissues were dissected for measurement of chemerin mRNA and blood taken for measures of catecholamines. ASO Chemerin reduced mean arterial blood pressure vs ASO control and PBS group within the first week, and remained reduced by ~17+/- 2 mm Hg at the time of sacrifice. Target organ mass (liver, heart and kidneys) was not different between ASO control and ASO chemerin group. HPLC revealed that circulating norepinephrine (NE) and dopamine (DA) were reduced 50% in the ASO chemerin vs control or PBS group. Real time RT-PCR validated knockdown of chemerin in ASO chemerin treated animals, with reductions as follows (vs ASO control, +/-3%): Liver (94%), epididymal fat (90%), retroperitoneal fat (90% ) and mesenteric perivascular adipose tissue (85%). These experiments provide powerful support for chemerin playing a role in blood pressure elevation.

Chemerin plays a protective role by regulating human umbilical vein endothelial cell-induced nitric oxide signaling in preeclampsia.

The aim of this study was to determine chemerin levels in preeclampsia and to assess the effects of this anti-inflammatory factor on endothelial nitric oxide synthase (eNOS), nuclear factor (NF)-κB, and vascular cell adhesion molecule (VCAM) expression in human umbilical vein endothelial cells (HUVECs). Serum chemerin and eNOS levels were measured by enzyme-linked immunosorbent assays, while chemerin mRNA and protein levels were measured by fluorescent quantitative polymerase chain reaction and Western blotting, respectively. Nitric oxide (NO) concentrations were determined with a colorimetric method. Akt and eNOS phosphorylation were assessed by Western blotting. We also tested the effects of the phosphoinositide 3-kinase inhibitor LY294002 and the eNOS inhibitor L-NAME. NF-κB p65 and VCAM-1 phosphorylation were assessed by Western blotting to investigate the role of chemerin in tumor necrosis factor (TNF)-α-induced HUVEC injury. Serum chemerin levels were increased in preeclampsia, while eNOS was decreased. Chemerin mRNA and protein were both increased in placentae from patients with preeclampsia. Furthermore, chemerin serum level positively correlated with blood pressure, body mass index, and serum insulin and was negatively correlated with serum eNOS. Chemerin dose-dependently increased NO concentrations in supernatants. Chemerin can increase eNOS and Akt levels in HUVECs, and these results could be partly blocked by LY294002 and L-NAME. Chemerin significantly decreased TNF-α-induced NF-κB and VCAM-1 in HUVECs, and these changes were partly inhibited by LY294002 and L-NAME. Chemerin may play a protective role by regulating NO signaling. Future studies should assess the role of chemerin in preeclampsia and other vascular diseases.