mRNA Expression Of Adiponectin Receptors Research Articles

Changes in adiponectin system after ventricular assist device in pediatric heart failure

Ventricular assist device (VAD) implant represents a therapeutic option for pediatric patients with end-stage heart failure (HF). Heart unloading by VAD can modify several molecular pathways underlying cardiac function in HF. Among them, the potential role of microRNA (miRNAs) in response to VAD implant is emerging. This study was aimed at investigating in HF pediatric patients the effect of VAD-modified miRNAs on the adiponectin (ADPN) system, known to exert cardioprotective actions. ADPN was measured in plasma samples obtained from HF children, before and 1month after VAD implant, and from healthy control children. miRNA profile and molecules belonging to ADPN system were determined in cardiac biopsies collected at the time of VAD implantation (pre-VAD) and at the moment of heart transplant (post-VAD). An in vitro study using HL-1 cell line was performed to verify the regulatory role of the VAD-modified miRNA on the ADPN system. VAD implant did not affect circulating and cardiac levels of ADPN, but increased the cardiac mRNA expression of ADPN receptors, including AdipoR1, AdipoR2, and T-cad. AdipoR2 and T-cad were inversely related to the VAD-modified miRNA levels. The in vitro study confirmed the regulatory role of miR-1246 and miR-199b-5p on AdipoR2, and of miR-199b-5p on T-cad. These data suggest that VAD treatment could regulate the expression of the cardioprotective ADPN system by epigenetic mediators, suggesting that miRNAs have a potential role as therapeutic targets to improve cardiac function in HF pediatric patients.

Sexual dimorphic metabolic and cognitive responses of C57BL/6 mice to Fisetin or Dasatinib and quercetin cocktail oral treatment

Senolytic treatment in aged mice clears senescent cell burden leading to functional improvements. However, less is known regarding the effects of these compounds when administered prior to significant senescent cell accumulation. From 4–13 months of age, C57BL/6 male and female mice received monthly oral dosing of either 100 mg/kg Fisetin or a 5 mg/kg Dasatinib (D) plus 50 mg/kg Quercetin (Q) cocktail. During treatment, several aspects of healthy aging were assayed including glucose metabolism using an insulin and glucose tolerance test, cognitive performance using Morris water maze and novel object recognition, and energy metabolism using indirect calorimetry. Afterwards, mice were euthanized for plasma, tissue specific markers of senescence-associated secretory phenotype (SASP), and white adipose tissue accumulation (WAT). Sexually dimorphic treatment effects were observed. Fisetin treated male mice had reduced SASP, enhanced glucose and energy metabolism, improved cognitive performance, and increased mRNA expression of adiponectin receptor 1 and glucose transporter 4. D + Q treatment had minimal effects in male C57BL/6 mice, but was detrimental to females causing increased SASP expression along with accumulation of WAT depots. Reduced energy metabolism and cognitive performance were also noted. Fisetin treatment had no effect in female C57BL/6 mice potentially due to a slower rate of biological aging. In summary, the senolytic treatment in young adulthood, has beneficial, negligible, or detrimental effects in C57BL/6 mice dependent upon sex and treatment. These observations should serve as a note of caution in this rapidly evolving and expanding field of investigation.Graphical Male and female C57BL/6 mice were treated with once monthly oral doses of either Dasatinib (D) + Quercetin (Q) or Fisetin from 4–13 months of age. Males treated with Fisetin had reduced SASP markers (blue spheres) as well as improved metabolism (red flame) and cognition. Females treated with D + Q had increased adiposity and SASP markers (red spheres) along with decreased metabolism (blue flame) and cognitive performance. No effects were observed in females treated with Fisetin or males treated with D + Q.

Adiponectin Reduces Lipid Content in Chicken Myoblasts by Activating AMPK Signaling Pathway.

Studies in mammals have shown that adiponectin is secreted mainly by adipocytes, and it plays a crucial role in glucose and lipid metabolism in muscles. Clarifying the cross-talk role of adiponectin between adipose tissue and skeletal muscle tissue is very important for internal homeostasis. The glucose and lipid metabolism of chicken is different from that of mammals, and the role of adiponectin in chickens is unclear. Therefore, it is of great significance to study the effect and mechanism of adiponectin on lipid metabolism in chickens. In the present study, the regulating effect of adiponectin on lipid metabolism in chicken myoblasts was explored by adding a certain concentration of exogenous recombinant adiponectin. Results showed that adiponectin reduced intracellular lipid content, increasing the mRNA expression of adiponectin receptor and cellular uptake of glucose and fatty acids. In addition, adiponectin activated the 5′ adenosine monophosphate activated protein kinase (AMPK) signaling pathway. The above results suggested that adiponectin reduced intracellular lipid content, mainly by binding to adiponectin receptor, activating AMPK pathway, increasing cellular uptake of glucose and fatty acids and promoting lipid oxidation.

Effect of Light-Dark Cycle Misalignment on the Hypothalamic-Pituitary-Gonadal Axis, Testicular Oxidative Stress, and Expression of Clock Genes in Adult Male Rats.

This study investigated the influence of circadian misalignment on the male reproductive system. Adult Sprague-Dawley male rats were exposed to prolonged light (20 h light : 4 h dark) or prolonged darkness (4 h light : 20 h dark) for 12 consecutive weeks. The somatic index of seminal vesicles and prostates increased due to prolonged light exposure. Sperm count and motility were enhanced solely by prolonged light exposure, whereas the percentage of sperm abnormalities was reduced by both prolonged light and darkness. The serum levels of reproductive hormones (follicle-stimulating hormone, luteinizing hormone, testosterone, and prolactin) were elevated, and the estradiol level was reduced by long-term light and dark exposure. Testicular total antioxidant capacity and antioxidant enzyme activities were improved, and lipid peroxidation was inhibited following chronic exposure to light or dark. Chronic light exposure increased, but chronic darkness decreased, testicular nitric oxide production. The mRNA expression of the hypothalamic and testicular clock genes including PER1-2, CRY1-2, BMAL1, CLOCK, and Rev-Erbα was altered by circadian disruption. Prolonged light exposure decreased the levels of thyroid hormones and suppressed the mRNA expression of adiponectin receptors 1 and 2. The immunohistochemical expression of proliferating cell nuclear antigen was decreased only by chronic darkness. The present study thus provides new insights into the physiological changes associated with long-term exposure to light or darkness, in which the expression levels of various clock gene mRNAs are modulated, reproductive hormones are increased, and the antioxidant enzyme system is ameliorated as mechanisms of adaptation to chronic circadian disruption.

Changes in circulating levels and cardiac expression of adiponectin system in children with heart failure after Ventricular Assist Device support

Abstract Background Ventricular Assist Device (VAD) is increasingly used as bridge to transplantation for the treatment adult and pediatric patients with end-stage Heart Failure (HF). Unloading of heart by VAD can lead to significant molecular, structural and functional changes of cardiac muscle in HF adult patients, including an improvement of the inflammatory process. Adiponectin (ADN), an anti-inflammatory adipokine, exerts anti-hypertrophic, anti-fibrotic and anti-apoptotic effects after binding to AdipoR1, AdipoR2 and T-CAD receptors. There is an apparently paradoxical increase of ADN levels in HF adult patients, probably due ADN resistance. VAD treatment leads to an increased cardiac expression of ADN receptors in HF adults. However, little is known about the role of ADN in HF children and the effects of VAD support on ADN system in these patients. Purpose The aims of this study were to evaluate: 1) the circulating ADN levels from HF children and a control group of healthy children; 2) the effects of VAD treatment both on circulating levels of ADN and on the cardiac expression of ADN system in pediatric patients with HF. Methods Circulating levels of ADN were measured in plasma samples collected from 8 HF children [age:57±33 (mean±SD) months; 2 males; 14.2±13.5 weight; 29±8 LVEF%] before and at 4 hrs, 1, 3, 7, 14 and 30 days after VAD implant. The ADN levels of paediatric patients at baseline were compared with a group of 107 [58±7 months; 67 males] healthy children. Expression levels of AdipoR1, AdipoR2, T-CAD were determined by real-time PCR in cardiac biopsies collected from HF children at the time of VAD implant (Pre-VAD) and at the time of heart transplantation (Post-VAD). Results Circulating levels of ADN were significantly higher in HF compared to healthy children (Figure 1A). In HF children, plasma ADN decreased significantly in early post-operative time-course (up to 3 days Post-VAD implant) and returned to pre-operative levels in 1 month (Figure 1B). In cardiac biopsies, mRNA expression of AdipoR1, AdipoR2, T-CAD increased significantly after VAD treatment compared to Pre-VAD (Figure 2A–C). Conclusion In pediatric patients, high circulating levels of ADN were associated with presence of HF and were modified by VAD implant, but remained significantly abnormal. On the other hand, an increased cardiac mRNA expression of ADN receptors was observed after VAD. These results could suggest the existence of a fine tuning of the ADN system at cardiac tissue level, able to mitigate plasma abnormality and favour the cardio-protective effect of ADN. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): SensorART-A Remote Controlled Sensorized ARTificial Heart Enabling Patients Empowerment and New Therapy Approaches

The protective effect of recombinant globular adiponectin on testis by modulating autophagy, endoplasmic reticulum stress and oxidative stress in streptozotocin-induced diabetic mice

This study was to investigate whether recombinant globular adiponectin produced its protective effect on the testis of diabetic mice by modulating autophagy, endoplasmic reticulum stress and oxidative stress. Male mice were randomly divided into control, diabetic, diabetic treated with low and high dose of adiponectin. Mice were killed at the termination after 4 weeks and 8 weeks of adiponectin treatment. Serum levels of glucose, lipids, testosterone, insulin, LH and FSH were measured. The protein expression of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), Caspase12, Beclin1, microtubule-associated protein light chain 3 (LC3) and p62 was determined by western blotting. The mRNA expression of adiponectin receptor 1 (AdipoR1), p22phox, p47phox, nuclear factor erythroid2-related factor 2 (Nrf2), NAD(P)H-quinone oxidoreductase 1(NQO1), heme oxygenase-1 (HO-1) and superoxide dismutase (SOD) were determined by real-time fluorescence quantitative PCR. The testicular weight, the sperm number and motility, and the serum levels of testosterone and insulin were significantly decreased in diabetic mice (P < 0.05). The expression of Beclin1, LC3, Nrf2, NQO1, HO-1, SOD and AdipoR1 were significantly decreased (P < 0.05), while the expression of GRP78, CHOP, Caspase12, p62, p22phox and p47phox were notably increased in the testes of diabetic mice (P < 0.05). Adiponectin treatment significantly reversed the above-mentioned changes in the testes of diabetic mice, some of which were dose- and time-dependent (P < 0.05). These data suggested that recombinant globular adiponectin may produce the protective effect on the testes of diabetic mice by inducing autophagy and inhibiting ER stress and oxidative stress.

Ghrelin antagonist regulates metabolic hormone receptorsin the hypothalamus of ewes

Abstract This study evaluates the effects of ghrelin antagonist on mRNA abundance for metabolic hormone receptors in feed-restricted ewes. Ewes were randomly assigned to one of three treatments; Control (CO): feed above maintenance energy intake requirements and daily subcutaneous saline infusion; Feed restriction (FR): feed restricted and daily subcutaneous saline infusion; Ghrelin antagonist (GA): feed restricted and daily subcutaneous of 7.5 μg/kg of d -Lys3-GHRP-6. Blood was sampled on days 1, 4, 9, and 13, relative to the start of the experiment, to quantify plasma glucose, NEFA and ghrelin concentrations. At day 13, the hypothalamus was collected to evaluate relative mRNA expression. The CO ewes had lesser plasma NEFA concentration compared with FR and GA ewes. There was a treatment by time interaction for plasma glucose concentration, all treatment started with similar plasma glucose concentration, but at day 13 CO ewes had a greater plasma concentration than FR and GA. Relative mRNA expression for glucagon receptor in GA ewes tended to be lesser compared with CO and FR treated ewes. There were no differences in insulin receptor mRNA relative expression between the groups. Ghrelin receptor mRNA relative expression tended to be greater in the GA compared with the CO treated ewes. There was no effect of GA on leptin receptors. However, there was a tendency toward greater relative expression of leptin receptor mRNA in the FR compared with the CO ewes. Relative expression of adiponectin receptor mRNA was lesser in the GA compared with CO and FR ewes. Cortisol receptor relative mRNA expression was greater in the FR compared with the CO ewes. Restricting dietary intake of ewes change mRNA relative expression of cortisol and leptin receptors in the hypothalamus of ewes. These variations are countered with ghrelin antagonist. Ghrelin antagonist modifies the mRNA relative expression of ghrelin, glucagon and adiponectin receptors. These results suggest that ghrelin could regulates metabolic hormone activity by modifying the relative expression of their receptors mRNA.

Adiponectin deficiency has no effect in murine autoimmune myocarditis

BackgroundAdiponectin is a hormone that together with its receptors modulates a number of metabolic processes including gluconeogenesis and lipid catabolism. It belongs to the C1QTNF (complement C1q tumor necrosis factor-related protein) family, which has a variety of members with high amino acid sequence homology and overlapping functions. Concentration of adiponectin in blood is inversely correlated with body fat percentage and cardiac risk factors like blood pressure and CRP (C-reactive protein) level. Studies have identified the existence of a cardiac adiponectin system. However, little is known about the role of this system in the pathogenesis of autoimmune myocarditis. Thus, we have studied the involvement of adiponectin in the development of this autoimmune disorder in a mouse model of experimental autoimmune myocarditis (EAM). MethodsAdiponectin knockout (ko) and wild type (wt) mice were immunized with cardiac troponin I (cTnI) to induce an EAM. To determine the severity of myocardial damage, inflammation and fibrosis were scored after HE and Afog staining and high sensitivity troponin T (hsTnT) level was measured. To detect if changes in specific inflammatory cell numbers could be observed between the genotypes, we performed immunohistochemical staining to detect T lymphocytes, B lymphocytes and macrophages. The level of the humoral immune response was determined through the measurement of cTnI-specific serum IgG autoantibodies. Relative mRNA expression of different cytokines, C1QTNF family members and adiponectin receptors in the heart tissue was analyzed with qPCR. ResultsAnimals immunized with cTnI developed autoimmune myocarditis with a significant deterioration of cardiac parameters compared to the corresponding control group. The adiponectin ko group immunized with cTnI showed a tendency towards increased inflammation, fibrosis, heart-to-body-weight ratio, infiltration pattern of T lymphocytes, B lymphocytes and macrophages, hsTnT concentration, humoral immune response and mRNA expression of interleukin 6 in the heart tissue and decreased weight gain compared to the wt group immunized with cTnI. However, the difference to the wt group treated with cTnI was not significant. The analysis of cardiac mRNA expression of adiponectin receptors and four C1QTNF family members, most suitable for fulfilling the functions of adiponectin in adiponectin ko mice, did not show any significant differences between adiponectin ko and wt group at all. ConclusionOur study reveals that the absence of adiponectin did not lead to a significantly increased impairment of cardiac function and was also unlikely to be compensated by its receptors or other C1QTNF family members in the murine model of EAM. Here, other synergistic or redundant effects might play a role and must be investigated in further studies to understand the role and function of adiponectin in autoimmune myocarditis.

LGA-newborn from patients with pregestational obesity present reduced adiponectin-mediated vascular relaxation and endothelial dysfunction in fetoplacental arteries.

Maternal obesity is associated with large-for-gestational-age (LGA) neonates and programming of obesity-related cardiovascular disease in the offspring, however, the mechanisms that lead to the later are unclear. Presently, interpretations of NO-dependent changes in vascular function in LGA newborn from obese mothers are conflicting. Adiponectin improves endothelial function by increasing eNOS activity and NO production. We propose that LGAs from obese mothers present a diminished vascular response to adiponectin; thus, affecting eNOS and AMPK activation. Chorionic arteries, umbilical cord and primary cultures of umbilical artery endothelial cells (HUAEC) were collected at term (>38 weeks) from uncomplicated singleton pregnancies of LGA and adequate-for-gestational (AGA) newborn. Vascular reactivity of chorionic plate arteries was assessed by wire myography. mRNA expression of adiponectin receptors 1 (AdipoR1) and AdipoR2 in HUAEC was determined by qPCR. Protein expression of AdipoR1, AdipoR2, AMPK, phospho-AMPKαThr172 , eNOS, and phospho-eNOSSer1177 after stimulation with AdipoRon was determined by Western Blot. Maximal adiponectin-induced chorionic artery relaxation in LGAs was diminished compared to control. In vitro studies showed no differences in expression of AdipoRs, total AMPK and, eNOS activation between groups; however, higher expression of total eNOS and AMPK activation in HUAEC of LGA relative to AGAs were observed. LGA HUAEC showed diminished NO production and eNOS activity compared to AGA in response to AdipoRon but no changes in AMPK activation. Placental endothelium of LGAs shows a diminished vascular response to adiponectin. Moreover, eNOS activation and adiponectin-dependent NO production is lower in HUAEC of LGA from obese mothers, indicating they present dysfuncional placental-endothelial responses.

10-Hydroxy-2-decenoic acid, a natural product, improves hyperglycemia and insulin resistance in obese/diabetic KK-Ay mice, but does not prevent obesity.

10-Hydroxy-2-decenoic acid (10H2DA) is a fatty acid found in royal jelly (RJ). In healthy mice, it activates 5’-AMP-activated protein kinase (AMPK) and increases glucose transporter 4 (GLUT4) translocation. Therefore, we examined whether 10H2DA has a potential therapeutic effect against type 2 diabetes in obese/diabetic KK-Ay mice. 10H2DA (3 mg/kg body weight) was administered to female KK-Ay mice for 4 weeks by oral gavage. Phenotypes for body weight, plasma glucose by oral glucose tolerance test and insulin levels were measured. mRNA and protein levels were determined using qRT-PCR and Western blot analyses, respectively. Long-term administration of 10H2DA significantly improved hyperglycemia and insulin resistance in KK-Ay mice, but did not prevent obesity. 10H2DA increased the expression of phosphorylated AMPK (pAMPK) protein in skeletal muscles; however, this expression did not correlate with increased GLUT4 translocation. Furthermore, 10H2DA neither enhanced the expression of adiponectin receptor mRNA nor activated the insulin signaling cascade, such as GSK-3β phosphorylation, in the liver. We found that 10H2DA-treated mice had a significant increase in the expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (Pgc-1α) mRNA in skeletal muscles compared with non-treated group (P=0.0024). These findings suggest that 10H2DA is involved in the improvement of type 2 diabetes, at least in part via activation of Pgc-1α expression, but does not prevent obesity.

Beneficial effects of n-3 polyunsaturated fatty acids on adiponectin levels and AdipoR gene expression in patients with type 2 diabetes mellitus: a randomized, placebo-controlled, double-blind clinical trial.

IntroductionThere is evidence that n-3 polyunsaturated fatty acids (n-3 PUFAs) exert beneficial effects to improve type 2 diabetes mellitus (T2DM), but its complications remain poorly understood. Hypoadiponectinemia is one of the important mechanisms responsible for T2DM which necessitates developing novel therapeutic strategies. We aimed to determine the effect of n-3 PUFA supplementation on circulating adiponectin and mRNA expression of adiponectin receptors (AdipoR1, AdipoR2) and Sirt-1 in T2DM patients.Material and methodsA randomized, double-blind, placebo-controlled trial of 10-week follow-up of n-3 PUFAs (2.7 g/day) vs. placebo in T2DM patients (n = 88) was conducted. In detail, T2DM patients (n = 44) were treated with n-3 PUFAs and the remainder received placebo. Anthropometric and metabolic characteristics were assessed in all participants. Circulating level of adiponectin and mRNA expression of AdipoR1, AdipoR2 and Sirt-1 were measured in peripheral blood mononuclear cells (PBMC) using real-time polymerase chain reaction before and after the intervention.ResultsIt was found that n-3 PUFAs increased AdipoR1 gene expression (fold change = 1.321 in n-3 PUFAs vs. 1.037 in placebo) and AdipoR2 mRNA (fold change = 1.338 in n-3 PUFAs vs. 1.034 in placebo). No significant changes were observed for Sirt-1 expression. The serum level of adiponectin significantly (p = 0.035) increased in n-3 PUFAs (5.09 to 5.58 μg/ml) but remained unchanged in the placebo group.ConclusionsDaily supplementation with n-3 PUFAs (2.7 g) was effective to significantly improve gene expression of AdipoR1 and AdipoR2 and the serum level of adiponectin in T2DM patients. Therefore, n-3 PUFAs might emerge as an adjuvant for current antidiabetic therapies. However, confirmatory long-term studies are required.

Effects of Exercise on Adiponectin Receptors mRNA Expression During Insulin Resistant Formation of Rats

Effects of Exercise on Adiponectin Receptors mRNA Expression During Insulin Resistant Formation of Rats

Expression of adiponectin receptors 1 and 2 in the ovary and concentration of plasma adiponectin during the oestrous cycle of the pig

The aim of this study was to compare the expression levels of adiponectin receptor 1 and adiponectin receptor 2 mRNAs and proteins in porcine ovaries during four stages (days 2 to 3, 10 to 12, 14 to 16, 17 to 19) of the oestrous cycle and to measure adiponectin plasma concentrations during the same phases of the cycle. Higher mRNA expression of adiponectin receptor 1 was detected in porcine granulosa cells than in corpora lutea and theca cells (P < 0.01). In contrast, higher gene expression of adiponectin receptor 2 occurred in newly developed and mature corpora lutea (P < 0.01). The adiponectin receptor 1 protein content was the highest in corpora lutea isolated on days 2 to 3 of the cycle and was the lowest in theca interna cells (P < 0.01). The profile of adiponectin receptor 2 protein was similar to that of adiponectin receptor 1. Adiponectin plasma concentrations were significantly higher throughout the luteal phase than in the follicular phase (P < 0.01). In conclusion, the presence of adiponectin receptor 1 and adiponectin receptor 2 mRNAs and proteins in the porcine ovary suggests that adiponectin may directly affect ovarian functions through its own specific receptors. The expression of both receptors and adiponectin plasma concentration were dependent on hormonal status related to the stage of the cycle.

AdipoR1/APPL1 potentiates the protective effects of globular adiponectin on angiotensin II-induced cardiac hypertrophy and fibrosis in neonatal rat atrial myocytes and fibroblasts.

Atrial hypertrophy and fibrosis are essential pathological features of atrial fibrillation. Recently, adiponectin has become a protein of interest due to its beneficial effects on cardiovascular diseases. However, the molecular mechanism of atrial structural remodeling and signaling pathways evoked by adiponectin remain unclear. In the present study, we investigated the cardioprotective effect of globular adiponectin (gAcrp) on angiotensin II-induced atrial hypertrophy and fibrosis in neonatal Sprague-Dawley rat. To further investigate the molecular mechanisms underlying the preventive effect of gAcrp, transfection of cells with siRNA was used to suppress the mRNA expression of adiponectin receptor 1 (AdipoR1) and its downstream adaptor protein APPL1. Non-silencing-Cy-3 labelled siRNA was used to determine transfection efficiency using fluorescence microscopy. The expression of atrial natriuretic peptide and procollagen type1 α-1, hypertrophy marker and fibrosis one, respectively, was detected by real-time PCR. Furthermore, the expression of adenosine monophosphate-activated protein kinase (AMPK), phosphatidylinositol 3-kinase (PI3K) and Akt was detected by western blotting. In addition, nuclear p65 translocation activity was analyzed by EMSA supershift assay. Our results showed that AdipoR1 and the adaptor protein APPL1 mediated the protective effects of gAcrp. In addition, the function of adiponectin and phosphorylation of AMPK were prominently diminished by inhibition of PI3K. Furthermore, nuclear factor-κB (NF-κB) transcription was diminished by the specific inhibition of AMPK. Taken together, AMPK pivotally interacts with NF-κB and PI3K, mediating the cardioprotective effect of adiponectin, and may serve as a therapeutic target for preventing atrial hypertrophy and fibrosis. Our present study suggests that gAcrp could ameliorate AngII-induced cardiac hypertrophy and fibrosis in rat atrial cells, which is mediated by the activation of AMPK signaling pathways. APPL1 and AdipoR1 are the key factors involved in the downstream of gAcrp approach.

Down-regulation of adiponectin receptors in osteoarthritic chondrocytes.

The objective of this study was to investigate the expression of adiponectin receptors (AdipoR1, R2, and T-cadherin) in both normal subjects and patients with knee osteoarthritis (OA). We used immunofluorescence to assess expression of adiponectin receptors in the chondrocytes of normal subjects (n = 3) and OA patients (n = 3). We also studied mRNA expression of adiponectin receptors in both groups by real-time polymerase chain reaction (real-time PCR). Finally, we utilized Western blotting to confirm the presence of adiponectin receptors. As compared with osteoarthritic chondrocytes, normal chondrocytes showed stronger immunoreactivity for AdipoR1, AdipoR2, and T-cadherin. The expression levels of both AdipoR1 and AdipoR2 mRNA were significantly lower in the osteoarthritic chondrocytes compared with those in the normal chondrocytes, 19 ± 2 and 36 ± 3 % of normal chondrocytes, respectively (P < 0.001). T-cadherin mRNA expression levels of the osteoarthritic chondrocytes were also lower than those in the normal chondrocytes, but not statistical significant (P = 0.072). The expression levels of AdipoR1 and AdipoR2 protein were significantly higher in the normal chondrocytes compared with those in the osteoarthritic chondrocytes (P < 0.001, P < 0.01, respectively). T-cadherin protein expression level of the normal chondrocytes was also higher than those in the osteoarthritic chondrocytes, but the difference is not statistical significant (P = 0.114). Expression of adiponectin receptors protein in normal and osteoarthritic chondrocytes is consistent with its mRNA expression levels. In conclusion, we report for the first time down-regulation of adiponectin receptors (AdipoR1, R2, and T-cadherin) in osteoarthritic chondrocytes. Decreased adiponectin receptors in OA may reduce the tissue sensitivity to adiponectin, thus lost the protection from adiponectin in the progression of OA.

Up-Regulation of Adiponectin Expression in Antigravitational Soleus Muscle in Response to Unloading Followed by Reloading, and Functional Overloading in Mice

The purpose of this study was to investigate the expression level of adiponectin and its related molecules in hypertrophied and atrophied skeletal muscle in mice. The expression was also evaluated in C2C12 myoblasts and myotubes. Both mRNA and protein expression of adiponectin, mRNA expression of adiponectin receptor (AdipoR) 1 and AdipoR2, and protein expression of adaptor protein containing pleckstrin homology domain, phosphotyrosine binding domain, and leucine zipper motif 1 (APPL1) were observed in C2C12 myoblasts. The expression levels of these molecules in myotubes were higher than those in myoblasts. The expression of adiponectin-related molecules in soleus muscle was observed at mRNA (adiponectin, AdipoR1, AdipoR2) and protein (adiponectin, APPL1) levels. The protein expression levels of adiponectin and APPL1 were up-regulated by 3 weeks of functional overloading. Down-regulation of AdipoR1 mRNA, but not AdipoR2 mRNA, was observed in atrophied soleus muscle. The expression of adiponectin protein, AdipoR1 mRNA, and APPL1 protein was up-regulated during regrowth of unloading-associated atrophied soleus muscle. Mechanical loading, which could increase skeletal muscle mass, might be a useful stimulus for the up-regulations of adiponectin and its related molecules in skeletal muscle.

Clinical immunology Comparison of phenotype, chondrogenic and osteogenic potential of rheumatoid mesenchymal stem cells derived from articular and subcutaneous adipose tissue - the role of adipocytokines

A study was carried out to compare the phenotype, chondrogenic and osteogenic potential of adipose mesenchymal stem cells (ASCs) derived from articular adipose tissue (AAT) and subcutaneous adipose tissue (ScAT) of rheumatoid arthritis (RA) patients. We also aimed to evaluate the role of leptin (LEP), low molecular weight adiponectin isoform (LMW), high molecular weight adiponectin isoform (HMW) and tumor necrosis factor (TNF) in ASCs differentiation. AAT and ScAT were obtained from RA patients undergoing total knee joint replacement surgery. ASCs were isolated and expanded in vitro. Cells phenotype was assesed by flow cytometry; leptin and adiponectin receptors mRNA expression by RT-PCR. Differentiation was performed in chondrogenic and osteogenic medium with or without LEP, LMW, HMW and TNF. After differentiation, expression of mRNA for Sox9, aggrecan (Agr), collagen 2a (Col2a) for chondrogenesis, and BMP-2, Runx-2 and osteopontin (OPN) for osteogenesis was evaluated by RT-PCR. Dickkopf-1 (DKK-1) and osteoprotegerin (OPG) proteins concentrations were measured in supernatants from osteogenic cultures using ELISA. AAT and ScAT-ASCs have the same CD105+CD90+CD73+CD45–CD34+/–CD19–CD14– phenotype. AAT-ASCs seem to be more susceptible to chondrogenesis and osteogenesis in vitro. Adipocytokines do not exert strong effect on ASCs differentiation, however HMW slightly increased expression of chondrogenesis markers mRNA in AATASCs. TNF diminished expression of all chondrogenesis markers and OPN, but enhanced expression of BMP-2 and Runx-2 mRNA.

Arterial Stiffness Is Associated With Increased Monocyte Expression of Adiponectin Receptor mRNA and Protein in Patients With Coronary Artery Disease

Arterial stiffness and carotid intima-media thickness (IMT) constitute validated cardiovascular prognostic markers. Adiponectin and its receptors 1 (AdipoR1) and 2 (AdipoR2) are involved in coronary artery disease (CAD). We investigated whether AdipoR1 and R2 mRNA and protein expression are associated with arterial stiffness, IMT and extent of coronary atherosclerosis. We studied 71 patients (61 men, 10 women) with angiographically proven CAD. We measured: (i) monocyte expression of AdipoR1 and AdipoR2 mRNA (quantitative real-time PCR) and protein expression (flow cytometry) (iii) adiponectin, metalloproteinase-9 (MMP-9) and C-reactive protein (CRP) blood levels, (iv) carotid-femoral artery pulse wave velocity (PWV) and carotid IMT. Patients with multi-vessel CAD had higher AdipoR1 and AdipoR2 mRNA than those with single-vessel (P < 0.05). PWV was associated with AdipoR1 mRNA (r = 0.474), AdipoR1 protein (r = 0.228), AdipoR2 mRNA (r = 0.716), AdipoR2-protein (r = 0.261), adiponectin (r = 0.236), and MMP-9 (r = 0.350) (P < 0.05, for all correlations). After adjustment for age, sex, waist-hip ratio, and mean blood pressure both AdipoR1 and AdipoR2 mRNA remained independent determinants of PWV (R(2) = 0.35 and R(2) = 0.57, P < 0.05). IMT was also associated with AdipoR2 mRNA, AdipoR2 protein, and MMP-9 (P < 0.05). Increased expression of ADR2 mRNA significantly related to MMP-9 (r = 0.210), and CRP (r = 0.531) (P < 0.05). Increased mRNA and protein expression of adiponectin receptors is related with increased aortic stiffness, coronary and peripheral atherosclerosis in patients with CAD. The interrelation of AdipoR2 with inflammatory markers, PWV and IMT suggests a compensatory increase of these receptors to counteract the excess inflammatory and atherogenic process in CAD. Thus, adiponectin receptors may provide a potential therapeutic target of agents activating their beneficial action.American Journal of Hypertension 2012; doi:10.1038/ajh.2012.42.

Effect of rosiglitazone on the expression of cardiac adiponectin receptors and NADPH oxidase in type 2 diabetic rats

This study investigated the effect of rosiglitazone on the expression of cardiac adiponectin receptors and NADPH oxidase in type 2 diabetic rats. Thirty-six male Wistar rats were randomly divided into control (C, n=10), diabetic (D, n=13) and diabetic treated with rosiglitazone (DT, n=13). Type 2 diabetes was induced by high-fat and high-sugar diet and intraperitoneal injection of a low dose of streptozotocin (STZ). Eleven rats in diabetic untreated group and twelve rats in diabetic treated group were successfully induced to be diabetes. After induction of diabetes, rosiglitazone (3mg/kg/day) was administrated to diabetic treated rats by gavage for 12weeks. Twelve weeks later, the heart function was detected. Plasma and myocardial adiponectin levels were detected by enzyme linked immunosorbent assay (ELISA). The cardiac mRNA expression of adiponectin receptors 1 and 2, and monocyte chemoattractant protein-1 (MCP-1) was assayed by reverse transcript-polymerase chain reaction (RT-PCR). The cardiac mRNA expression of p22phox and NOX4 was assayed by real-time fluorescence quantitative PCR. The cardiac protein expression of phosphor-AMPK-α (Thr172) and glucose transporter 4 (GLUT4) was determined by Western blotting. The protein expression of adiponectin receptors 1 and 2, and connective tissue growth factor (CTGF)were determined by immunohistochemistrial staining. The ratio of heart weight to body weight was significantly increased in diabetic rats compared to control. Heart function, plasma and myocardial adiponectin levels, the protein and mRNA expression of myocardial adiponectin receptors 1 and 2, myocardial phosphorylation of AMPK-α (Thr172) and the protein expression of myocardial GLUT4 were significantly decreased in diabetic rats compared to control (P<0.05). The expression of myocardial p22phox, Nox4, MCP-1 and CTGF was significantly increased in diabetic rats compared to control (P<0.05). Rosiglitazone treatment significantly attenuated the increased ratio of heart weight to body weight, and the increased expression of myocardial p22phox, Nox4, MCP-1 and CTGF in diabetic rats (P<0.05). Heart function, plasma and myocardial adiponectin levels, the expression of myocardial adiponectin receptors 1 and 2 and GLUT4, and myocardial phosphorylation of AMPK-α (Thr172) were significantly decreased in diabetic treated with rosiglitazone compared to diabetic untreated (P<0.05). These results suggest that the protective effects of rosiglitazone on diabetic rat hearts may be attributable to the increased myocardial adiponectin and its receptors and the decreased myocardial NADPH oxidase.

Effect of telmisartan on the expression of cardiac adiponectin and its receptor 1 in type 2 diabetic rats

This study investigated the effect of telmisartan on the expression of cardiac adiponectin and its receptor 1 in type 2 diabetic rats. Thirty-six male Wistar rats were randomly divided into control (C, n = 10) and diabetic (n = 26) groups. Type 2 diabetes was induced by high-fat and high-sugar diet and intraperitoneal injection of a low dose of streptozotocin (STZ). After induction of diabetes, diabetic rats were again randomly divided into diabetic (D, n = 10) and diabetic treated (DT, n = 10) groups. Telmisartan (5 mg/kg/day) was administrated to diabetic treated rats by gavage for 12 weeks. Twelve weeks later, the heart function was investigated. Plasma and myocardial adiponectin levels were detected by enzyme-linked immunosorbent assay (ELISA). The cardiac mRNA expression of adiponectin receptor 1 (adipiR1) was assayed by reverse transcript-polymerase chain reaction (RT-PCR). The cardiac protein expression of adipiR1, AMP-activated protein kinase (AMPK)-α, phospho-AMPK-α (Thr172) and glucose transporter 4(GLUT4) was determined by Western blotting. The ratio of heart weight to body weight was significantly increased in diabetic rats compared with control. The decreased levels of plasma and myocardial adiponectin and the decreased protein and mRNA expression of myocardial adipoR1 led to the decreased myocardial phosphorylation of AMPK-α (Thr172) and the decreased protein expression of myocardial GLUT4 in diabetic rats. Consequently, the heart function was decreased in diabetic rats. Telmisartan treatment significantly attenuated the increased ratio of heart weight to body weight in diabetic rats. The levels of plasma and myocardial adiponectin and the expression of myocardial adipoR1 in diabetic rats were upregulated by telmisartan. Subsequently, the levels of myocardial phospho-AMPK-α (Thr172) and the expression of myocardial GLUT4 in diabetic rats were increased by telmisartan. Consequently, the heart function was improved in diabetic rats treated with telmisartan. These results suggest that the levels of myocardial adiponectin and its receptor 1 are decreased in type 2 diabetic rats. Telmisartan treatment up-regulates the levels of myocardial adiponectin and its receptor 1, resulting in the increase in myocardial phospho-AMPK-α (Thr172) and GLUT4 expression, which may contribute to the improvement of heart function and the decrease in cardiac hypertrophy in diabetic rats.