AdipoR1 mRNA Research Articles

Trophoblast-specific overexpression of adiponectin receptor 2 causes fetal growth restriction in pregnant mice.

Maternal obesity in pregnancy is strongly associated with complications such as fetal overgrowth and infants of obese mothers have an increased risk to develop obesity, diabetes, and cardiovascular disease later in life. However, the underlying mechanisms are not well established. Circulating levels of adiponectin are low in obese pregnant women and maternal circulating adiponectin is negatively associated with birth weight. We have reported that normalizing maternal adiponectin in obese pregnant mice prevents placental dysfunction, fetal overgrowth, and programming of offspring cardio-metabolic disease. However, the mechanistic link between maternal adiponectin, placental function, and fetal growth remains to be established. We hypothesized that trophoblast-specific overexpression of the adiponectin receptor 2 (Adipor2) in healthy pregnant mice inhibits placental mTORC1 signaling and nutrient transport, resulting in fetal growth restriction. Using lentiviral transduction of blastocysts with a mammalian gene expression lentiviral vector for up-regulation of Adipor2 (Adipor2-OX), we achieved a ~ 3-fold increase in placenta Adipor2 mRNA levels and a 2-fold increase of the ADIPOR2 protein in the trophoblast plasma membrane. Placenta-specific Adipor2-OX increased placental peroxisome proliferator-activated receptor-α phosphorylation, ceramide synthase expression and ceramide concentrations. Furthermore, Adipor2-OX inhibited placental mTORC1 signaling and reduced invivo placental transport of glucose and amino acids. Lastly, Adipor2-OX reduced fetal weight by 11%. These data provide mechanistic evidence that placental Adipor2 signaling directly affects fetal growth. We propose that low circulating adiponectin in maternal obesity causes fetal overgrowth and programs the offspring for cardio-metabolic disease mediated by a direct effect on placental function.

Globular adiponectin, acting via AdipoR1, regulates food intake of Siberian sturgeon (Acipenser baerii) in a mTOR dependent manner

Adiponectin (AdipoQ) is a hormone that regulates food intake and energy homeostasis in mammals. The globular adiponectin (gAd) has been reported involved in the regulation of appetite, but the regulatory role and mechanism in fish remains unelucidated. Using Siberian sturgeon as a model of Chondrostei, the recombinant gAd protein of Siberian sturgeon (SsgAd) was produced by Escherichia coli expression system and verified using western blotting. Intraperitoneal injection of recombinant SsgAd protein at 100 ng/g BW suppressed food intake 1 h after administration. Peripheral injection of SsgAd protein caused the upregulation of anorexigenic pyy expression in the valvula intestine, but did not affect cck expression in the valvula intestine and orexigenic ghrelin expression in the stomach. The SsgAd administration significantly increased the hypothalamic expressions of pomc and decreased npy, agrp, and cart expression. In addition, SsgAd recombinant protein promoted adipor1, ampkα2, akt, and mtor mRNA expressions within the hypothalamus, whereas inhibited ampkβ1, ampkβ2 and ampkγ2 mRNA expression, suggesting AMPK and mTOR signaling pathways might be related to SsgAd protein-mediated anorexia activity. Furthermore, the injection of an mTOR antagonist (rapamycin) reversed the reduced food intake and npy, agrp, and cart expression due to the peripheral injection of SsgAd, as well as the increased pomc expression induced by SsgAd, which were not observed after AMPK antagonist (dorsomorphin) treatment. In summary, the current study, for the first time, suggest that the anorexigenic function of SsgAd might bind with AdipoR1 and activate the mTOR signal pathway to affect the expression of hypothalamic appetite factors in Siberian sturgeon. This study provides new insight into the molecular mechanism of AdipoQ in feeding regulation in fish, and a basis for further exploration on physiological function of AdipoQ.

Maternal brown rice diet alleviates adverse effects of maternal obesity on offspring metabolism via enhancing DNA demethylation of AdipoR2

The prevalence of maternal obesity is increasing at an alarming rate, with maternal insufficient circulating adiponectin being identified as a crucial link to offspring metabolic disorders. Nutritional interventions during pregnancy have shown promise in mitigating the negative impacts of maternal obesity on offspring health. It is recommended that pregnant women with chronic metabolic diseases increase their consumption of whole grains such as brown rice. However, the specific mechanism through which brown rice consumption by obese pregnant women improves metabolic homeostasis in their offspring remains unclear. Here, we investigated the effects of a brown rice diet during pregnancy on the metabolic homeostasis of offspring exposed to maternal obesity. We found that the systemic energy metabolism homeostasis and the risk of obesity induced by high-fat diet (HFD) in the offspring of obese mothers were altered by the maternal brown rice diet during pregnancy, including reducing systemic and hepatic lipid levels, improving insulin resistance, and protecting hepatic steatosis. Mechanistically, the maternal brown rice diet induced DNA methylation reprogramming in the livers of offspring mice, resulting in enhanced demethylation of the adiponectin receptor AdipoR2 and increased transcription of AdipoR2 mRNA. Adiponectin binding to AdipoR2, regulated hepatic lipid metabolism through AMPKα and PPARα-mediated pathways, effectively ameliorating metabolic disorders in offspring of obese mothers. Our study provides novel insights into combating obesity risk and lays the groundwork for further exploration of the physiological benefits of whole grain brown rice.

Exploring the Impact of Nitric Oxide and Epidermal Growth Factor Receptor on Vascular Remodeling Induced by Mechanical Stretch

Hypertension is a key risk factor in many cardiovascular diseases like heart failure, kidney failure and vascular hypertrophy. Mechanical stretch/hypertension, promotes vascular smooth muscle cells remodeling by inducing leptin expression and other hypertrophic proteins like ERK1/2, AKT, and cofilin. Also the Epidermal growth factor receptor (EGFR) transactivation has shown to mediate vascular remodeling by enhancing VSMC hypertrophy, migration, and proliferation. Nitric oxide (NO) has been shown to be a critical factor for many cellular physiological function, it has the ability to induce VSMC relaxation leading to reduce hypertension. Moreover NO has received extensive attention as an anti- hypertrophic agent. Several Studies have shown that nitric oxide does not only promote vasodilation but it also inhibits VSMC proliferation. The major aim of this study was to investigate the inhibitory effect of NO and the effect of blocking the EGFR in mechanical stretch induced vascular remodeling. Methods: Rat portal veins (RPVs) were isolated and pretreated with/without NO donor (SNAP) or EGFR kinase blocker (AG1478) and then stretched to study their effects on mechanical stretch induced leptin synthesis and VSMC remolding. Western blot analysis was done to detect protein expression for leptin, adiponectin, eNOS p-ERK1/2 and p-AKT. Immunocytochemistry was performed on rat aortic vascular smooth muscle (RASMC) to detect GATA-4 nuclear translocation. Moreover, we used laser confocal microscopy on frozen RPV sections to detect the level of ROS formation and leptin. Finally, we performed qPCR for adiponectin, adipoR1 and adipoR2 mRNA. Results: In this study we showed the effect of mechanical stretch at different time points (1hour and 24 hours). Mechanical stretch-induced leptin expression was mediated by ERK1/2, AKT activations and ROS formation. These effects were associated with eNOS and adiponectin downregulation. Mechanical stretch had no effect on the expression of adiponectin receptors (adipoR1 and adipoR2). RASMCs pretreated with 3.1 nmol/L for 3 hours had induced GATA-4 nuclear translocation. Pre-incubation the RPV with SNAP significantly decreased mechanical stretch induced leptin expression, ERK1/2 and AKT phosphorylation. Moreover, SNAP significantly inhibited the adiponectin downregulation by mechanical stretch. Leptin-induced GATA-4 nuclear translocation was inhibited by SNAP. The involvement of EGFR transactivation in mechanical stretch-induced leptin expression was investigated using AG1478. Pretreatment of RPVs with AG1478 had no effect on mechanical stretch-induced early leptin expression (1 hour) while it inhibited mechanical stretch-induced late leptin expression (24 hours), ROS formation, and adiponectin and eNOS downregulation. However, treatment with AG1478 showed no effect on leptin-induced GATA-4 nuclear translocation. Conclusion: This study showed that NO has a direct inhibitory effect on mechanical stretch-induced AKT and ERK1/2 pathways and inhibits ROS formation that leads to vascular remodeling. On the other hand, EGFR transactivation was able to mediate mechanical stretch-induced vascular hypertrophy via ROS formation and leptin production, thus making EGFR and NO a promising therapeutic target for hypertension induced hypertrophy. This work was funded by Qatar University grants award UREP27-050-3-020 from Qatar National Research Fund (a member of Qatar Foundation) to AZ. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Osteocalcin activates lipophagy via the ADPN-AMPK/PPARα-mTOR signaling pathway in chicken embryonic hepatocyte

Fatty liver hemorrhage syndrome (FLHS) is the leading cause of noninfectious mortality in caged layers worldwide. Osteocalcin (OCN) is a protein secreted by osteoblasts, and its undercarboxylated form (ucOCN) acts as a multifunctional hormone that protects laying hens from FLHS. Lipophagy is a form of selective autophagy that breaks down lipid droplets (LDs) through lysosomes, and defective lipophagy is associated with FLHS. The aim of this study was to investigate the effects of ucOCN on the lipophagy of chicken embryonic hepatocytes and associated the function of the adiponectin (ADPN) signaling pathway. In this study, chicken embryonic hepatocytes were divided into 5 groups: control (CONT), fat emulsion (FE, 10% FE, v/v), FE with ucOCN at 1 ng/mL (FE-LOCN), 3 ng/mL (FE-MOCN), and 9 ng/mL (FE-HOCN). In addition, 4 μM AdipoRon, an adiponectin receptor agonist, was used to investigate the function of ADPN. The results showed that compared with CONT group, FE promoted the levels of phosphorylation of mammalian target of rapamycin (p-mTOR) (P < 0.05) and decreased the mRNA expression of ADNP receptors (AdipoR1 and AdipoR2). Compared with FE group, 3 and 9 ng/mL ucOCN inhibited the levels of autophagy adaptor p62 and p-mTOR (P < 0.05), increased the ratios of LC3-II/LC3-I (P < 0.05) and phosphorylated adenosine 5'-monophosphate-activated protein kinase (p-AMPK)/AMPK (P < 0.05), as well as the levels of peroxisome proliferator-activated receptor α (PPAR-α) and ADPN (P < 0.05). In addition, ucOCN at the tested concentrations increased the colocalization of LC3 and LDs in fatty hepatocytes. Administrated 4 μM AdipoRon activated AdipoR1 and AidpoR2 mRNA expression (P < 0.05), decreased the concentrations of triglyceride (P < 0.05), without effects on cell viability (P > 0.05). AdipoRon also increased the LC3-II/LC3-I ratio (P < 0.05) and the levels of p-AMPK/AMPK and PPAR-α (P < 0.05). In conclusion, the results reveal that ucOCN regulates lipid metabolism by activating lipophagy via the ADPN-AMPK/PPARα-mTOR signaling pathway in chicken embryonic hepatocytes. The results may provide new insights for controlling FLHS in laying hens.

Activation of POMC neurons to adiponectin participating in EA-mediated improvement of high-fat diet IR mice.

Insulin resistance (IR) is one of the common pathological manifestations of metabolic-related diseases, and the prevalence of relevant diseases is high. Acupuncture is beneficial to IR patients, but the central mechanism underlying this treatment remains unclear. This study provides mechanistic insights into how electroacupuncture (EA) improves IR through the response of Pro-opiomelanocortin (POMC) neurons to adiponectin (Adipo). Glucose tolerance tests (GTT), Insulin tolerance tests (ITT) and fasting blood glucose (FBG) were detected by glucometer. Serum insulin, Adipo and skeletal muscle adiponectin receptor 1 (AdipoR1) protein levels were examined by ELISA. Homeostasis model assessment estimated insulin resistance (HOMA-IR) was calculated using the following formula: HOMA-IR = fasting insulin (FINS) (mU/L) × FBG (mmol/L)/22.5. The expression levels of AdipoR1 and Adipo mRNA in skeletal muscle were detected by real-time PCR quantification. The co-marking of c-Fos/AdipoR1 and POMC neurons were investigated using immunofluorescence. Spontaneous excitatory postsynaptic currents (sEPSCs) of POMC neurons and the response of POMC neurons to Adipo were detected via electrophysiology. EA significantly ameliorated HFD-induced impairment of GTT, ITT, FBG, and HOMA-IR which was correlated with recovery of the expression level of AdipoR1 and Adipo in skeletal muscle. The improved response of POMC neurons to Adipo in the hypothalamus may be a key factor in correcting abnormal glucose tolerance and improving IR. This study demonstrates that EA can ameliorate HFD-induced impaired glucose tolerance through improved response of POMC neurons to Adipo in the hypothalamus, providing insight into the central mechanism of improving IR through EA.

Metabolic memory determines oviductal gene expression of underfed ewes during early gestation

Our aim was to investigate the oviduct environment by studying oviduct gene expression after undernutrition in day-5 pregnant ewes with different initial (i) BCS, and its association with the number of embryos recovered. Thirty-six ewes were divided into 2 groups with different iBCS: iBCS ≥2.75 (n = 19; high, H) and iBCS ≤2.25 (n = 17; low, L), and were randomly assigned to two nutritional treatments for 20 days: 1.5 (control, C) or 0.5 (underfed, U) times the daily maintenance requirements. Thus, the final four groups were: high-iBCS control (HC, n = 9), high-iBCS underfed (HU, n = 10), low-iBCS control (LC, n = 9) and low-iBCS underfed (LU, n = 8). Samples of oviduct were collected and the expression of target genes was quantified using real-time PCR. While high-iBCS control ewes presented more ADIPOR1 mRNA than the high-iBCS underfed group (P < 0.05) and low-iBCS control ewes (P = 0.01), high-iBCS underfed group presented higher ADIPOR2 gene expression than low-iBCS underfed ewes (P < 0.01) evidencing a differential oviductal gene expression for these receptors. In high-iBCS ewes, control animals presented higher IGFBP2 gene expression than underfed ewes (P < 0.05), associated these results with a poor oviductal environment. High-iBCS underfed ewes presented higher IGFBP4 gene expression than high-iBCS control ewes (P < 0.05). Stepwise regression models, using various combinations of data on metabolic and reproductive hormones, and oviduct gene expression as independent variables, identified a set of variables that accounted for 75% of the variation in the number of embryos recovered. In conclusion, the oviductal gene expression depends on body reserves and nutritional treatment, and the effect is gene-specific.

Abstract 15261: Adipor2 Sirna-Mediated Knockdown Predominantly Polarizes Towards a M1 Phenotype in THP-1 Macrophages

Introduction: Monocyte-derived macrophages (Mϕs) are the major innate immune cells in plaques, where they assume a more pro-inflammatory (M1) or anti-inflammatory (M2) Mϕ phenotype. Notably, M1 Mϕs are more abundant in unstable plaques, while M2 in stable plaques. Adiponectin receptor 1 (AdipoR1) and AdipoR2 are highly expressed in the monocyte/Mϕ lineage and largely mediate immune responses. Herein, we investigated the specific contribution of AdipoR1 and AdipoR2 on polarization towards a M1 or M2 Mϕ phenotype. Methods: siRNA-mediated knockdown of AdipoR1 and/or AdipoR2 was performed in THP-1 monocyte-derived Mϕs, and collected to perform, 1) qRT-PCR analyses on AdipoR1 and AdipoR2, and 2) flow cytometry analyses on M1 Mϕ markers: CD86, CD80, MHC-II, and M2 Mϕ markers: CD206, CD163. Results: For qRT-PCR analyses, siRNA-mediated knockdown of single AdipoR1 and AdipoR2 significantly decreased the mRNA levels of their respective receptor (p&lt;0.01, p&lt;0.0001), while the opposing receptor was unaffected. Double knockdown resulted in a significant decrease in both AdipoR1 and AdipoR2 mRNA levels (p&lt;0.001, p&lt;0.0001). For flow cytometry analyses, single AdipoR1 and double AdipoR1/R2 siRNA led to a significant decrease in ΔMFI (mean fluorescence intensity) of MHC-II (p&lt;0.01), while a significant increase was observed in single AdipoR2 siRNA (p&lt;0.01). Intracellular siRNA-mediated knockdown of AdipoR1 and/or AdipoR2 did not result in a significant loss of their cell surface expression, as confirmed via dot plots analyses. Lastly, single AdipoR1 and double AdipoR1/R2 siRNA exhibited decreased % MHC-II/CD86-positive cells (p&lt;0.01, p&lt;0.001), while single AdipoR2 siRNA increased % MHC-II/CD86-positive cells (p&lt;0.05). Conclusions: Despite intracellular siRNA-mediated knockdown of AdipoR1 and/or AdipoR2, their cell surface expression remains intact. Furthermore, single AdipoR2 siRNA was associated with an increase in M1 Mϕ population (MHC-II/CD86), which is in line with our previous evidence showing decreased AdipoR2 signalling in unstable plaques. Thus, downregulation of AdipoR2 may play a role in polarization predominantly towards a M1 phenotype in THP-1 Mϕs and hence could be mechanistically relevant in the development of unstable plaques.

Adiponectin and adiponectin receptors in common carp (Cyprinus carpio): Tissue distribution and their expressions in response to high-carbohydrate and high-lipid diets

In order to investigate the roles of adiponectin in glucose and lipid metabolism in common carp, the tissue distribution of adiponectin and its receptor genes in common carp were firstly detected in this study, and then the effects of high-carbohydrate (45%) and high-lipid (11%) diets on their expressions were studied in the feeding trial. The results showed that adipoqa and adipoqb mRNA levels were highest in the red muscle, followed by the heart and white muscle. Adiponectin receptor genes were widely expressed in all tested tissues. Two subtypes of adiponectin receptor 1 genes (adipor1a and adipor1b) were expressed at the highest level in the brain, while adipor2 mRNA was highly expressed in the heart and red muscle. The high-carbohydrate diet significantly up-regulated adipoqa and adipoqb mRNA level in the heart of common carp, while the high-lipid diet significantly promoted adipoqa mRNA expression in the red muscle and heart, compared to the control diet. For adiponectin receptor gene expression, a high-carbohydrate diet up-regulated adipor2 mRNA level in the hepatopancreas, while a high-lipid diet significantly promoted adipor1a, adipor1b and adipor2 mRNA expression in the red muscle and hepatopancreas. The results showed that both high-carbohydrate and high-lipid diets could induce adiponectin genes expression in common carp, and AdipoRs expression was more likely to be increased by the high-lipid diet than the high-carbohydrate diet. This study suggested that adiponectin and its receptors were involved in the metabolic regulation of fish under high dietary carbohydrate and lipid levels.

Celecoxib-mediated attenuation of non-alcoholic steatohepatitis is potentially relevant to redistributing the expression of adiponectin receptors in rats

Pharmacological inhibition of cyclooxygenase-2 (COX-2) activity ameliorated the severity of non-alcoholic steatohepatitis (NASH) rats. It is not completely understood that the role of COX-2 inhibitor celecoxib on adiponectin receptors (Adipo-R1/R2) expression in different tissues in NASH rats. Sprague-Dawley male NASH rats induced by a high-fat diet (HFD) were administrated with or without celecoxib for 8 weeks. Biochemical parameters of liver function, glucose, and lipid metabolism, and the levels of adiponectin, tumor necrosis factor-alpha (TNF-α), prostaglandin E2 (PGE2) in the serum or liver were collected according to the standard protocols. The mRNA and protein levels of Adipo-R1, Adipo-R2, and COX-2 in the liver, muscle, and visceral fat were performed by quantitative real-time polymerase chain reaction (q-PCR) and Western blot analysis, respectively. The results showed that celecoxib ameliorated the various clinical indicators and pathological characteristics in the NASH rats, including body weight, liver function, liver index, and redox activities in serum and hepatic samples. The serum concentrations of adiponectin and TNF-α and PGE2 were negatively correlated. As expected, these ameliorative effects of celecoxib were associated with the gene and protein levels up-regulation of Adipo-R1, Adipo-R2 in the liver and visceral fat tissues, and seeming to be compensatory down-regulation expression in muscle tissues (P <0.05). Additionally, COX-2 protein expression was negatively correlated with serum adiponectin levels, protein expression of adiponectin receptors from the liver and visceral fat, conversely, positively correlated with those from the muscle. Our current study demonstrate that celecoxib might effectively alleviate NASH rats in a unique manner closely relevant to redistributing the expression of adiponectin receptors in the liver, visceral fat, and muscle. However, the precise molecular mechanism needs further study.

Identification of miRNAs involved in liver injury induced by chronic exposure to cadmium

To elaborate the molecular mechanism underlying the hepatotoxicity induced by chronic exposure to cadmium (Cd), a mouse model with hepatocyte-specific deletion of Ppp2r1a (encoding protein phosphatase 2 A Aα subunit, PP2A Aα) gene was used to investigate the effect of cadmium exposure on liver injury. The wild type littermates (WT) and PP2A Aα-/- mice (KO) were treated with cadmium chloride (CdCl2) at concentrations of 0 mg/L, 10 mg/L, 100 mg/L in drinking water for 3, 6 and 9 months (KO mice only for 9 months), respectively. The pathological findings were characterized by progressive inflammation, steatosis, and liver fibrosis upon treatment of CdCl2 in a dose-response and time-dependent manner. Notably, PP2A Aα depletion leads to a more profound liver injury induced by CdCl2 treatment. The transcriptome analysis in livers of KO mice revealed 20 differentially expressed microRNAs (miRNAs) appeared in both 3- and 9-month. Particularly, the alterations of miR-34a-5p, miR-345-5p, and miR-30e-5p expressions were implicated in the development of liver disease and correlated with the degree of liver injury induced by cadmium treatment. Further analysis indicated that miR-34a-5p, miR-345-5p, and miR-30e-5p might be involved in CdCl2-induced liver injury, in part by dysregulation of lipid metabolism and inflammation. The in vitro studies showed that miR-34a-5p was involved in regulation of CdCl2-induced cytotoxicity through directly targeted adiponectin receptor 2 (AdipoR2) mRNA. Taken together, we identified that specific miRNAs were implicated in hepatotoxicity induced by chronic exposure to CdCl2. These findings also provide new insight into the role of PP2A in regulation of miRNAs-mediated liver injury.

Estradiol overcomes adiponectin-resistance in diabetic mice by regulating skeletal muscle adiponectin receptor 1 expression

Adiponectin and insulin resistance creates a vicious cycle that exacerbates type 2 diabetes. Earlier, we observed that female leptin receptor-deficient BLKS mice (BKS-db/db) were more sensitive to an adiponectin mimetic GTDF than males, which led us to explore if E2 plays a crucial role in modulation of adiponectin-sensitivity. Male but not female BKS-db/db mice were resistant to metabolic effects of globular adiponectin treatment. Male BKS-db/db displayed reduced skeletal muscle AdipoR1 protein expression, which was consequent to elevated polypyrimidine tract binding protein 1 (PTB) and miR-221. E2 treatment in male BKS-db/db, and ovariectomized BALB/c mice rescued AdipoR1 protein expression via downregulation of PTB and miR-221, and also directly increased AdipoR1 mRNA by its classical nuclear receptors. Estrogen receptor regulation via dietary or pharmacological interventions may improve adiponectin resistance and consequently ameliorate insulin resistance in type 2 diabetes.

Cardiac miRNAs were involved in the regulation of pathophysiological mechanisms underlying HF in pediatric patients after ventricular assist device implantation

Abstract Background VAD use in heart failure (HF) children have undergone rapid progress in the last three decades through pump technological innovation and improvement of perioperative care. Studies in HF adults showed that VAD put native heart at rest and lead to molecular changes in cardiac muscle, including at microRNA (miRNA) level. However, little is known on changes induced by VAD implant in cardiac miRNA expression and their putative targets in HF children. Purpose The aims of this study were to evaluate: 1) modification of miRNA expression in cardiac muscle from HF children after VAD support; 2) the putative targets of selected miRNAs by in silico analysis; 2) the role of the identify miRNAs on putative targets by in vitro study. Methods Cardiac biopsies were collected from HF children at the moment of VAD implant [n=8; 20 (7.5–64.5) months, 2 males; 19 (15.75–32.25) LVEF%] and at the time of heart transplant after VAD support [n=5; 32 (5–204) months; 4 males; 13.5 (10–18) LVEF%]. Cardiac miRNA expression was evaluated by NGS. The potential miRNA targets were identified by bioinformatics analyses and their cardiac expression by real-time PCR was evaluated. HL-1 cell line was used for testing the regulatory role of selected miRNA on predicted targets by miRNA mimic transfection study. Results At NGS, 465 miRNA were found on average in each sample and the cardiac expression levels of miR19a-3p, miR-1246 and miR-199b-5p decreased in HF children after VAD support compared to pre-implant (Fig. 1A-B). In silico analysis showed that more than 5000 potential gene targets regulated by miR-19a-3p, miR-1246 and miR-199b-5p. Among them, adiponectin receptors (AdipoR1, AdipoR2, T-CAD) were identified as common targets for 3 miRNAs. Real-time PCR data showed that levels of all adiponectin receptors increased significantly whilst the expression of 3 miRNAs decreased after VAD support (Fig. 1C). Moreover, AdipoR2 and T-CAD were inversely related to miRNA levels (Fig. 1D). In vitro studies confirmed the regulatory role of miR-1246 and miR-199b-5p on AdipoR2 (Fig. 1E-F), whilst only miR-199b-5p reduced the expression of T-CAD (Fig. 1G). Finally, AdipoR1 expression levels are not modified compared to control by miRNAs mimic transfection (data not shown). Conclusion In HF children the use of VAD could modify the expression of several miRNAs potentially involved in the regulation of several pathophysiological mechanisms underlying HF. Specifically, the reductions of miR-1246, mir-19a-3p, miR-199b-5p were associated with an increase of the adiponectin receptors AdipoR2 and T-CAD mRNA, suggesting the existence of a miRNAs related fine tuning of the adiponectin system at cardiac tissue level by VAD implant, able to favour the protective effect of adiponectin in HF cardiac muscle. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): FP7-ICT-2009 Project, Grant Agreement 24863 Figure 1

Spinal Cord Injury Reduces Serum Levels of Fibroblast Growth Factor-21 and Impairs Its Signaling Pathways in Liver and Adipose Tissue in Mice.

Spinal cord injury (SCI) results in dysregulation of carbohydrate and lipid metabolism; the underlying cellular and physiological mechanisms remain unclear. Fibroblast growth factor 21 (FGF21) is a circulating protein primarily secreted by the liver that lowers blood glucose levels, corrects abnormal lipid profiles, and mitigates non-alcoholic fatty liver disease. FGF21 acts via activating FGF receptor 1 and ß-klotho in adipose tissue and stimulating release of adiponectin from adipose tissue which in turn signals in the liver and skeletal muscle. We examined FGF21/adiponectin signaling after spinal cord transection in mice fed a high fat diet (HFD) or a standard mouse chow. Tissues were collected at 84 days after spinal cord transection or a sham SCI surgery. SCI reduced serum FGF21 levels and hepatic FGF21 expression, as well as β-klotho and FGF receptor-1 (FGFR1) mRNA expression in adipose tissue. SCI also reduced serum levels and adipose tissue mRNA expression of adiponectin and leptin, two major adipokines. In addition, SCI suppressed hepatic type 2 adiponectin receptor (AdipoR2) mRNA expression and PPARα activation in the liver. Post-SCI mice fed a HFD had further suppression of serum FGF21 levels and hepatic FGF21 expression. Elevated serum free fatty acid (FFA) levels after HFD feeding were observed in post-SCI mice but not in sham-mice, suggesting defective FFA uptake after SCI. Moreover, after SCI several genes that are implicated in insulin’s action had reduced expression in tissues of interest. These findings suggest that downregulated FGF21/adiponectin signaling and impaired responsiveness of adipose tissues to FGF21 may, at least in part, contribute to the overall picture of metabolic dysfunction after SCI.

ADIPOR1 deficiency-induced suppression of retinal ELOVL2 and docosahexaenoic acid levels during photoreceptor degeneration and visual loss

Lipid metabolism-related gene mutations can cause retinitis pigmentosa, a currently untreatable blinding disease resulting from progressive neurodegeneration of the retina. Here, we demonstrated the influence of adiponectin receptor 1 (ADIPOR1) deficiency in retinal neurodegeneration using Adipor1 knockout (KO) mice. Adipor1 mRNA was observed to be expressed in photoreceptors, predominately within the photoreceptor inner segment (PIS), and increased after birth during the development of the photoreceptor outer segments (POSs) where photons are received by the visual pigment, rhodopsin. At 3 weeks of age, visual function impairment, specifically photoreceptor dysfunction, as recorded by electroretinography (ERG), was evident in homozygous, but not heterozygous, Adipor1 KO mice. However, although photoreceptor loss was evident at 3 weeks of age and progressed until 10 weeks, the level of visual dysfunction was already substantial by 3 weeks, after which it was retained until 10 weeks of age. The rhodopsin mRNA levels had already decreased at 3 weeks, suggesting that reduced rhodopsin may have contributed to early visual loss. Moreover, inflammation and oxidative stress were induced in homozygous KO retinas. Prior to observation of photoreceptor loss via optical microscopy, electron microscopy revealed that POSs were present; however, they were misaligned and their lipid composition, including docosahexaenoic acid (DHA), which is critical in forming POSs, was impaired in the retina. Importantly, the expression of Elovl2, an elongase of very long chain fatty acids expressed in the PIS, was significantly reduced, and lipogenic genes, which are induced under conditions of reduced endogenous DHA synthesis, were increased in homozygous KO mice. The causal relationship between ADIPOR1 deficiency and Elovl2 repression, together with upregulation of lipogenic genes, was confirmed in vitro. Therefore, ADIPOR1 in the retina appears to be indispensable for ELOVL2 induction, which is likely required to supply sufficient DHA for appropriate photoreceptor function and survival.

Mechanism of Huo-Xue-Qu-Yu Formula in Treating Nonalcoholic Hepatic Steatosis by Regulating Lipid Metabolism and Oxidative Stress in Rats.

Huo-Xue-Qu-Yu formula (HXQYF) is a prescription consisting of Ginkgo biloba leaf and Paeonia lactiflora Pall. for treating hyperlipidemia and NAFLD in China. Here, we investigated the hepatic and renal function, oxidative stress and lipid metabolism, and potential mechanisms of HXQYF on nonalcoholic fatty liver disease (NAFLD) rat models. NAFLD rat models were induced with high-fat diet (HFD) and 10% fructose water for 18 weeks and orally administered with or without HXQYF simultaneously. The results showed that HXQYF (22.5, 45, 90 mg/kg) significantly improved blood lipid levels via reducing serum TC, TG, LDL-C, and APOB values and elevating HDL-C and APOA1 levels in NAFLD rats. The higher levels of ALT, AST, CR, and BUN in serum induced by HFD were reduced by HXQYF. HE staining showed that HXQYF (90 mg/kg) reduced the accumulation of fat droplets and alleviated inflammatory response in liver cells. Three doses of HXQYF exhibited notable antioxidant effects by elevating SOD, GSH, and CAT activities and decreasing MDA and OH-1 levels in the liver. Furthermore, abnormal lipid metabolism caused by HFD was alleviated by HXQYF, which was associated with the upregulation of PPAR-α, AdipoR2, and CPT1 mRNAs as well as the downregulation of CYP2E1 and SREBP-1c mRNAs in liver tissue. In conclusion, our work verified that HXQYF could reduce the degree of hepatic steatosis, suppress oxidative stress, and attenuate lipid metabolism, thus preventing NAFLD.

The effect of adiponectin and its receptors in placental development of diabetic rats

Placenta development is an essential process for normal fetal growth and development, and healthy pregnancy maintenance. Inadequate placental development may cause clinical complications like diabetes, intrauterine growth retardation and preeclampsia. Due to limited data about placental expression of adiponectin, which has anti-diabetic effects, we studied the relationship between adiponectin and placental development in streptozotocin (STZ)-induced diabetic and normal rats. We also investigated Adiponectin receptors and the downstream adiponectin molecules like peroxisome proliferator-activated receptor (PPAR) α, PPARγ, retinoic acid receptor (RXR)α in the development of the diabetic placenta to explain the effects of Adiponectin in detail. Diabetic rat placentas were found to be heavier than control placentas at the 18th and 20th gestational days, while diabetic embryos were lighter than control group at the 14th, 18th and 20th days of gestation. Adiponectin protein level decreased in diabetic placenta towards term. Moreover, maternal serum adiponectin levels were found to be significantly decreased in diabetic group. Adiponectin receptor 1 (AdipoR1) mRNA expression levels were similar between groups, while Adiponectin receptor 2 (AdipoR2) mRNA expression was significantly decreased at the 14th, 18th and 20th days of gestation in diabetic placentas. Additionally, the mRNA and protein expression of PPARα, PPARγ, and RXRα were found to be decreased in diabetic placentas. These observations show that diabetes and pregnancy is associated with adiponectin levels. In conclusion, our data reveals that adiponectin plays a role in improvement of placental development in diabetic conditions, in the investigated animal species.

A novel c.-652C>T mutation in UCHL1 gene is associated with the growth performance in Yangzhou goose

As a member of the ubiquitin-dependent proteasome degradation pathway, Ubiquitin carboxyl-terminal hydrolase-L1 (UCHL1) plays a key role in post-translational modification and protein degradation, and it is extensive and important for the regulation of various biological functions of the organism. However, its function remains unclear in goose growth performance. In this study, the full-length genomic DNA and coding region of UCHL1 gene was firstly cloned and characterized in Yangzhou goose. Tissue expression profile revealed that UCHL1 was exclusively expressed in brain and gonads. A novel single nucleotide polymorphisms c.-652C>T which is significantly related to 64-d body weight of Yangzhou goose was found in UCHL1 promoter region by comparative sequencing. Correlation analysis in a population of 405 geese showed that TT genotype individuals had higher body weight than CC individuals in male, but not in female geese. Dual-luciferase reporter assay indicated that the single nucleotide polymorphisms c.-652C>T is located at the core promoter region of UCHL1, and the promoter transcription activity was significantly increased (P < 0.01) when allele C changed to T. Geese with TT genotype had higher mRNA level of UCHL1 in brain tissue than those of CC genotype (P < 0.01). Compared with CC individuals, neuropeptide Y and AdipoR1 mRNA level was significantly higher in TT individuals (P < 0.05), while FAS mRNA level was lower in the TT individuals (P < 0.05). In summary, we identify a novel mutation in the promoter of UCHL1 gene, which can alter transcriptional activity of UCHL1 gene, and affect the growth performance of male goose.

Leucine regulates porcine muscle fiber type transformation via adiponectin signaling pathway

Leucine can promote slow-twitch muscle fibers formation, and this effect may be mediated by AMPK signaling pathway. In addition, adiponectin (AdipoQ) plays an important role in regulation of muscle fiber type transformation. AdipoQ is located in the upstream of AMPK and its secretion can be regulated by leucine. Therefore, the aim of this study was to explore whether leucine affects muscle fiber type transformation through AdipoQ signaling pathway. Our data showed that 4 mM leucine significantly increased protein expression levels of slow MyHC, Myoglobin, Troponin I-SS, AdipoQ, AdipoR1, phospho-AMPK (p-AMPK) and PGC-1α and mRNA expression levels of AMPKα2, PGC-1α, AdipoQ and AdipoR1, and significantly decreased fast MyHC protein expression. In addition, 4 mM leucine significantly increased the SDH activity while significantly decreased the LDH activity. However, knockdown of AdipoR1 expression by AdipoR1-siRNA abolished leucine-induced upregulation of protein expressions of slow MyHC, AdipoR1, p-AMPK, PGC-1α and NRF1, mRNA expressions of MyHC I, MyHC IIa, AdipoR1, AMPKα2 and PGC-1α, ATP5G, TFAM and NRF1, and mtDNA level, as well as downregulation of protein expression of fast MyHC and mRNA expression of MyHC IIb. Together, our data revealed that leucine promotes muscle fiber type transformation from fast-twitch to slow-twitch through AdipoQ signaling pathway.

Gonadal Cycle-Dependent Expression of Genes Encoding Peptide-, Growth Factor-, and Orphan G-Protein-Coupled Receptors in Gonadotropin- Releasing Hormone Neurons of Mice.

Rising serum estradiol triggers the surge release of gonadotropin-releasing hormone (GnRH) at late proestrus leading to ovulation. We hypothesized that proestrus evokes alterations in peptidergic signaling onto GnRH neurons inducing a differential expression of neuropeptide-, growth factor-, and orphan G-protein-coupled receptor (GPCR) genes. Thus, we analyzed the transcriptome of GnRH neurons collected from intact, proestrous and metestrous GnRH-green fluorescent protein (GnRH-GFP) transgenic mice using Affymetrix microarray technique. Proestrus resulted in a differential expression of genes coding for peptide/neuropeptide receptors including Adipor1, Prokr1, Ednrb, Rtn4r, Nmbr, Acvr2b, Sctr, Npr3, Nmur1, Mc3r, Cckbr, and Amhr2. In this gene cluster, Adipor1 mRNA expression was upregulated and the others were downregulated. Expression of growth factor receptors and their related proteins was also altered showing upregulation of Fgfr1, Igf1r, Grb2, Grb10, and Ngfrap1 and downregulation of Egfr and Tgfbr2 genes. Gpr107, an orphan GPCR, was upregulated during proestrus, while others were significantly downregulated (Gpr1, Gpr87, Gpr18, Gpr62, Gpr125, Gpr183, Gpr4, and Gpr88). Further affected receptors included vomeronasal receptors (Vmn1r172, Vmn2r-ps54, and Vmn1r148) and platelet-activating factor receptor (Ptafr), all with marked downregulation. Patch-clamp recordings from mouse GnRH-GFP neurons carried out at metestrus confirmed that the differentially expressed IGF-1, secretin, and GPR107 receptors were operational, as their activation by specific ligands evoked an increase in the frequency of miniature postsynaptic currents (mPSCs). These findings show the contribution of certain novel peptides, growth factors, and ligands of orphan GPCRs to regulation of GnRH neurons and their preparation for the surge release.