PEGylated AdipoRon Analogs Improve Glucose Homeostasis and Lipid Metabolism in Mice under Insulinopenic and High Fat Diet Conditions
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ABSTRACT: Since the first report of AdipoRon as an orally active adiponectin receptor (AdipoR1/2) agonist, several studies have investigated its protective, metabolic and anti-cancer effects in the liver, kidney, heart, central nervous system and ovaries. Despite that, the effects of AdipoRon on pancreatic -cell function are yet to be addressed. Furthermore, the various AdipoRon actions reported to date have only been assessed at a rather high oral dosage without attempts to enhance its affinity and/or bioavailability. To examine how structural modifications can affect AdipoRon-induced multifaceted actions, we describe a series of AdipoRon analogs that contain amphiphilic ethylene glycol chains. Among these, we propose AdipoRonPEG5 as a more potent derivative of AdipoRon in exerting pleiotropic actions in mice under insulinopenic and high fat diet (HFD) conditions. While both AdipoRon and AdipoRonPEG5 substantially attenuate palmitate-induced lipotoxicity in INS-1 cells in a dose-dependent manner, only AdipoRonPEG5 treatment is accompanied by a marked expression of genes involved in maintaining the functional state of β-cells along with a significant reduction in ceramides. Similarly, AdipoRonPEG5 can induce a substantial reduction of pancreatic, hepatic and serum ceramide species, with a concomitant increase in the corresponding sphingoid bases, and improves insulin sensitivity of mice under HFD feeding conditions. Furthermore, hyperglycemia in STZ-induced insulinopenic adiponectin null mice is also attenuated upon AdipoRonPEG5 treatment. Our results suggest that AdipoRonPEG5 is more effective in reducing lipotoxicity in the pancreas and liver of HFD-fed mice than AdipoRon at 5 mg/Kg dosage and is consistent with adiponectin cytoprotective effect of β-cells. Additionally, these results indicate that the beneficial effects AdipoRonPEG5 can be partially attributed to improved pharmacokinetics compared to AdipoRon, thus providing the opportunity for further derivatization to achieve improved affinity and tissue-specific targeting.
Project description:Although innate immunity is critical for antifungal host defense against the human opportunistic fungal pathogen Aspergillus fumigatus, potentially damaging inflammation must be controlled. Adiponectin (APN) is an anti-inflammatory adipokine, and we observed 100% mortality and increased fungal burden and inflammation in neutropenic mice with invasive aspergillosis (IA) that lack APN or the APN receptors AdipoR1 or AdipoR2. Alveolar macrophages (AMs), early immune sentinels that detect and respond to lung infection, express both receptors, and APN-/- AMs exhibited an inflammatory/M1 phenotype that was associated with decreased fungal killing and decreased activation of LC3-associated phagocytosis (LAP). Furthermore, AM treatment with the AdipoR agonist AdipoRon partially rescued deficient killing in APN-/- AMs that was dependent on both receptors. Our study identifies a novel role for APN in LC3-mediated killing of A.fumigatus.
Project description:Cells and organisms require proper membrane composition to function and develop. Phospholipids are the major component of membranes and are primarily acquired through the diet. Given great variability in diet composition, cells must be able to deploy mechanisms that correct deviations from optimal membrane composition and properties. Here, using unbiased lipidomics and proteomics, we found that the embryonic lethality in mice lacking the fluidity regulators Adiponectin Receptors 1 and 2 (AdipoR1/2) is associated with aberrant high saturation of the membrane phospholipids. Using mouse embryonic fibroblasts (MEFs) derived from AdipoR1/2-KO embryos, human cell lines and the model organism C. elegans we found that, mechanistically, AdipoR1/2-derived sphingosine 1-phosphate (S1P) signals in parallel through S1PR3-SREBP1 and PPARγ to sustain the expression of the fatty acid desaturase SCD and maintain membrane properties. Thus, our work identifies an evolutionary conserved pathway by which cells and organism maintain membrane homeostasis and adapt to a variable environment.
Project description:Mutations in the adiponectin receptor 1 gene (AdipoR1) lead to retinitis pigmentosa and are associated with age-related macular degeneration (AMD). This study explores the effects of AdipoR1 gene deficiency in mice, revealing a striking decline in ω3 polyunsaturated fatty acids (PUFA), an increase in ω6 FAs, and elevated ceramides in the retina. The AdipoR1 deficiency impairs peroxisome proliferator-activated receptor α (PPARα) signaling, which is crucial for FA metabolism, particularly affecting proteins associated with FA transport and oxidation in the retina and retinal pigmented epithelium (RPE). Our lipidomic and proteomic analyses indicate changes that could affect membrane composition and viscosity through altered ω3 PUFA transport and synthesis, suggesting a potential influence of AdipoR1 on these properties. Furthermore, we noted a reduction in the Bardet-Biedl syndrome (BBS) proteins, which are crucial for forming and maintaining photoreceptor outer segments that are PUFA-enriched ciliary structures. Diminution in BBS-proteins content combined with our electron microscopic observations raises the possibility that AdipoR1 deficiency might impair ciliary function. Treatment with inhibitors of ceramide synthesis led to substantial elevation of ω3 LC-PUFAs, alleviating photoreceptor degeneration and improving retinal function. These results serve as the proof of concept for a ceramide-targeted strategy to treat retinopathies linked to PUFA deficiency, including AMD.
Project description:Adiponectin is a hormone secreted primarily by white adipose tissue. Recent studies have shown that adiponectin and its receptors (AdipoR1 and AdipoR2) are expressed in different reproductive tissues, including the ovary and uterus. This newly discovered endocrine system plays an important role in the regulation of reproductive processes. The aim of this study was to explore the influence of adiponectin on global gene expression in the porcine endometrium during early gestation, on days 15 to 16 of pregnancy (implantation period).
Project description:Obesity is associated with impairments of wound healing and tissue regeneration. Angiogenesis, the formation of new blood capillaries, plays a key role in organ regeneration and repair. Inhibition of lung angiogenesis impairs regenerative lung growth after unilateral pneumonectomy (PNX). However, the effects of obesity on post-PNX lung vascular and alveolar morphogenesis remain unclear. In this report, we have demonstrated that regenerative lung growth and angiogenic factor VEGFA expression induced by PNX are inhibited in Lepob/ob obese mice compared to Lepob/- mice. The levels of adiponectin, one of the adipokines that exhibits pro-angiogenic and vascular protective properties, increase in endothelial cells (ECs) isolated from remaining mouse lungs after unilateral PNX, while these effects are attenuated in Lepob/ob obese mice. Post-PNX lung growth, vascular and alveolar morphogenesis, and VEGFA levels in the lungs are inhibited in adiponectin knockout mice. Adiponectin agonist, AdipoRon stimulates post-PNX lung growth and vascular and alveolar morphogenesis in Lepob/ob obese mice. These findings suggest that obesity impairs lung vascular and alveolar regeneration and adiponectin may be one of the key molecules to improve lung regeneration in obese people.
Project description:The burden of senescent hepatocytes correlates with MASLD severity but mechanisms driving senescence, and how it exacerbates MASLD are poorly understood. Hepatocytes become senescent when Smoothened (Smo) is deleted to disrupt Hedgehog signaling. We aimed to determine if the secretomes of Smo-deficient hepatocytes perpetuate senescence to drive MASLD progression. RNA seq analysis confirmed that hepatocyte populations of MASLD livers are depleted of Smo(+) cells and enriched with senescent cells. When fed CDA-HFD, Smo(-) mice had lower antioxidant markers and developed worse DNA damage, senescence, MASH and liver fibrosis than Smo(+) mice. Sera and hepatocyte-conditioned medium from Smo(-) mice were depleted of thymidine phosphorylase (TP), a protein that maintains mitochondrial fitness. Treating Smo(-) hepatocytes with TP reduced senescence and lipotoxicity; inhibiting TP in Smo(+) hepatocytes had the opposite effects and exacerbated hepatocyte senescence, MASH, and fibrosis in CDA-HFD-fed mice.Therefore, we found that inhibiting Hedgehog signaling in hepatocytes promotes MASLD by suppressing hepatocyte production of proteins that prevent lipotoxicity and senescence.
Project description:To identify the mechanism underlying AdipoR1-mediated beneficial effect of exercise, we used RNA-Seq analysis to study the transcriptomic profiles of mice after 4-month wheel running exercise. Differential expression analysis was performed by comparing exercised mice to control mice, and exercised mice subjected to AdipoR1 shRNA versus exercised mice.
Project description:The ectopic deposition of fat is thought to lead to lipotoxicity and has been associated with mitochondrial dysfunction and diabetic cardiomyopathy. We have measured mitochondrial respiratory capacities in the hearts of ob/ob and wild-type mice on either a regular chow (RCD) or high-fat (HFD) diet across four age groups to investigate the impact of diet and age on mitochondrial function alongside a comprehensive strategy for metabolic profiling of the tissue. Myocardial mitochondrial dysfunction was only evident in ob/ob mice on RCD at 14 months, but it was detectable at 3 months on the HFD. Liquid chromatography–mass spectrometry (LC–MS) was used to study the profiles of acylcarnitines and the accumulation of triglycerides, but neither class of lipid was associated with mitochondrial dysfunction. However, a targeted LC–MS/MS analysis of markers of oxidative stress demonstrated increases in GSSG/GSH and 8-oxoguanine, in addition to the accumulation of diacylglycerols, which are lipid species linked to lipotoxicity. Our results demonstrate that myocardial mitochondria in ob/ob mice on RCD maintained a similar respiratory capacity to that of wild type until a late stage in aging. However, on a HFD, unlike wild-type mice, ob/ob mice failed to increase mitochondrial respiration, which may be associated with a complex I defect following increased oxidative damage.
2015-11-17 | MTBLS173 | MetaboLights
Project description:Transcriptome analysis of adiponectin receptor stimulated by AdipoRon in prostate cancer cells
Project description:Abstract Background In obesity, adipose tissue undergoes a remodeling process characterized by increased adipocyte size (hypertrophia) and number (hyperplasia). The individual ability to tip the balance toward the hyperplastic growth, with recruitment of new fat cells through adipogenesis, seems to be critical for a healthy adipose tissue expansion, as opposed to the development of inflammation and detrimental metabolic consequences. However, the molecular mechanisms underlying this fine-tuned regulation are far from being understood. Methods We analyzed by mass spectrometry-based proteomics visceral white adipose tissue (vWAT) samples collected from C57BL6 mice fed with a HFD for 8 weeks. A subset of these mice, called low responders (LowR HFD), showed a low susceptibility to the onset of adipose tissue inflammation, as opposed to their HFD counterpart. We identified the discriminants between LowR HFD and HFD vWAT samples and explored their function in Adipose Derived human Mesenchymal Stem Cells (AD-hMSCs) differentiated to adipocytes. Results We quantified 6051 proteins. Among the candidates that most differentiate LowR HFD from HFD vWAT, we found proteins involved in adipocyte function, including adiponectin and hormone sensitive lipase, suggesting that adipocyte differentiation is enhanced in LowR HFD, as compared to HFD. The chromatin modifier SET and MYND Domain Containing 3 (SMYD3), whose function in adipose tissue was totally unknown, was another top-scored hit. SMYD3 expression was significantly higher in LowR HFD vWAT, as confirmed by western blot analysis. In vitro, we found that SMYD3 mRNA and protein levels decrease rapidly along the differentiation process of AD-hMSCs. Moreover, SMYD3 knock-down at the beginning of adipocyte differentiation resulted in reduced cell proliferation and, at longer term, reduced lipid accumulation in adipocytes. Conclusions Our study describes for the first time the role of SMYD3 as a regulator of adipocyte proliferation during the early steps of adipogenesis.