Project description:Although the cannabinoid CB1 receptor has been implicated in atherosclerosis, its cellspecific effects in this disease are not well understood. Here, we report that male mice with myeloid-specific Cnr1 deficiency on atherogenic background developed smaller lesions and necrotic cores than controls, while only minor genotype differences were observed in females. Male Cnr1 deficient mice showed reduced arterial monocyte recruitment and macrophage proliferation with less inflammatory phenotype. The sexspecific differences in proliferation were dependent on estrogen receptor (ER)α estradiol signaling. Kinase activity profiling revealed a CB1-dependent regulation of p53 and cyclin-dependent kinases. Transcriptomic profiling further unveiled chromatin modifications, mRNA processing and mitochondrial respiration among the key processes affected by CB1 signaling, which was supported by metabolic flux assays. Chronic administration of the peripherally-restricted CB1 antagonist JD5037 inhibited plaque progression and macrophage proliferation, but only in male mice. Finally, CNR1 expression was detectable in human carotid endarterectomy plaques and inversely correlated with proliferation, oxidative metabolism and inflammatory markers, hinting to a possible implication of CB1-dependent regulation in human pathophysiology. In conclusion, impaired macrophage CB1 signaling is atheroprotective by limiting their arterial recruitment, proliferation and inflammatory reprogramming. The importance of macrophage CB1 signaling seems to be more pronounced in male mice.
Project description:The cannabinoid 1 receptor (CB1) regulates insulin sensitivity and glucose metabolism in peripheral tissues. CB1 is expressed on pancreatic beta (β)-cells where its functions have not been fully described. We generated a β-cell-specific CB1-knockout (β-CB1-/-) mouse to study the long-term consequences of CB1 ablation on β-cell function in adult mice. β-CB1-/- mice had increased basal- and stimulated-insulin secretion and intra-islet cAMP levels, resulting in primary hyperinsulinemia, as well as increased β-cell viability, proliferation, and islet area. Hyperinsulinemia led to insulin resistance, which was aggravated by a high fat/high glucose diet and weight gain, although β-cells maintained their insulin secretory capacity in response to glucose. Strikingly, islets from β-CB1-/- mice were protected from diet-induced inflammation. Mechanistically we show that this is a consequence of curtailment of oxidative stress and reduced activation of Nlrp3 inflammasome in β-cells. Our data demonstrate CB1 to be a negative regulator of β-cells and a mediator of islet inflammation under conditions of metabolic stress.
Project description:Triple-negative breast cancer (TNBC) is a subtype of breast cancer (BC) characterized by deletion of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (Her-2). It accounts for 10.0% to 20.8% of all pathological types of BC, has specific biological behavior and clinicopathological features, and has a worse prognosis than other types. TNBC usually has a high mortality and recurrence rate, and a poor prognosis after surgery, radiation, chemotherapy, and endocrine therapy. There are no conventional and effective treatments to control its progression. Therefore, we designed and developed a derivative based on Abemaciclib, named LA-CB1. To investigate the influence of LA-CB1 on biological function of TNBC. We use the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT) to detect the viability of breast cancer cells. Evaluation of drug effects on cell migration and invasion by Transwell assays. Cell clone formation assay detects cell proliferation ability after drug addition. Subsequently, we determined the clinical significance and functional role of LA-CB1 through chick embryo experiments. Then, transcriptome sequencing technology (RNA-Seq) and bioinformatics methods were used to study the main pathway of LA-CB1 action on MDA-MB-231 cells. Western Blot assay verified the effect of LA-CB1 on the expression of CDK4/6-CyclinD1-Rb-E2F pathway protein. The compound LA-CB1 can inhibit the proliferation, colony formation, migration and invasion of TNBC cells. Effect of compound LA-CB1 on apoptosis and cell cycle detected by flow cytometry. The expression levels of CDK4, CDK6, CyclinD1, E2F1 and p-Rb proteins were positively correlated with LA-CB1 concentration. In summary, LA-CB1 showed a good anti-tumor cell proliferation effect, showing potential anti-TNBC drug candidate properties. This study provides new ideas and possibilities for TNBC treatment.
Project description:Inhibition of cannabinoid receptor 1 (CB1) has shown efficacy in reducing body weight and improving metabolic parameters, with the effects correlating with target engagement in the brain. Recently, the peripheral effects of inhibiting the CB1 receptor has been appreciated through studies in diet-induced obese and liver-specific CB1 KO mice. In this report, we systematically investigated gene expression changes in peripheral tissues of DIO mice treated with the CB1 inverse agonist AM251. CB1 receptor inhibition led to down-regulation of genes within the de novo fatty acid and cholesterol synthetic pathways, including SREBP-1 and -2, and their downstream targets in both liver and adipose tissue. In addition, genes involved in fatty acid Beta-oxidation were up-regulated with AM251 treatment, probably through the activation of PPARalpha. In adipose tissue, CB1 receptor inhibition led to the down-regulation of genes in the TNFalpha signal transduction pathway and possibly to the activation of PPARgamma, both of which would result in improved insulin sensitivity.
Project description:Long-lasting forms of postsynaptic plasticity commonly involve protein synthesis-dependent structural changes of dendritic spines. However, the relationship between protein synthesis and presynaptic structural plasticity remains unclear. Here, we investigated structural changes in cannabinoid-receptor 1 (CB1)-mediated long-term depression of inhibitory transmission (iLTD), a form of presynaptic plasticity that requires protein synthesis and involves a long-lasting reduction in GABA release. We found that CB1-iLTD in acute rat hippocampal slices was associated with protein synthesis-dependent presynaptic structural changes. Using proteomics, we determined that CB1 activation in hippocampal neurons resulted in increased ribosomal proteins and initiation factors, but decreased levels of proteins involved in regulation of the actin cytoskeleton, such as Arp2/3, and presynaptic release. Moreover, while CB1-iLTD increased ubiquitin/proteasome activity, ubiquitination but not proteasomal degradation was critical for structural and functional presynaptic CB1-iLTD. Thus, CB1-iLTD relies on both protein synthesis and ubiquitination to elicit structural changes that underlie long-term reduction of GABA release.
Project description:Peripherally restricted cannabinoid CB1 receptor antagonists without central side effects hold promise for treating metabolic disorders including diabetes and obesity. In atherosclerosis, the specific effects of peripheral CB1 signaling in vascular endothelial cells (ECs) remain incompletely understood.We performed en face in situ hybridization of Cnr1 in murine aortas, revealing a significantly increased expression of the CB1 encoding gene in ECs within atheroprone compared to atheroresistant regions. In vitro, CNR1 was upregulated by oscillatory shear stress in human aortic endothelial cells (HAoECs). Endothelial CB1 deficiency (Cnr1EC-KO) in female mice on atherogenic background resulted in pronounced endothelial phenotypic changes, with reduced vascular inflammation and permeability. This translated into attenuated plaque development with reduced lipid content as well as reduced white and brown adipose tissue mass and liver steatosis. Ex vivo imaging of carotid arteries via two-photon microscopy revealed less DIL-LDL uptake in Cnr1EC-KO. This was accompanied by a significant reduction of aortic endothelial caveolin-1 (CAV1) expression, a key structural protein involved in lipid transcytosis in female Cnr1EC-KO mice. In vitro, pharmacological blocking with CB1 antagonist AM281 reproduced the inhibition of CAV1 expression and LDL uptake in response to atheroprone shear stress in human aortic endothelial cells (HAoECs), which was dependent on cAMP-mediated PKA activation. Conversely, the CB1 agonist ACEA increased DIL-LDL uptake and CAV1 expression in HAoECs. Finally, treatment of atherosclerotic mice with the peripheral CB1 antagonist JD-5037 reduced plaque progression, CAV1 and endothelial adhesion molecule expression in female mice. These results confirm an essential role of endothelial CB1 to the pathogenesis of atherosclerosis.
Project description:Inhibition of cannabinoid receptor 1 (CB1) has shown efficacy in reducing body weight and improving metabolic parameters, with the effects correlating with target engagement in the brain. Recently, the peripheral effects of inhibiting the CB1 receptor has been appreciated through studies in diet-induced obese and liver-specific CB1 KO mice. In this report, we systematically investigated gene expression changes in peripheral tissues of DIO mice treated with the CB1 inverse agonist AM251. CB1 receptor inhibition led to down-regulation of genes within the de novo fatty acid and cholesterol synthetic pathways, including SREBP-1 and -2, and their downstream targets in both liver and adipose tissue. In addition, genes involved in fatty acid Beta-oxidation were up-regulated with AM251 treatment, probably through the activation of PPARalpha. In adipose tissue, CB1 receptor inhibition led to the down-regulation of genes in the TNFalpha signal transduction pathway and possibly to the activation of PPARgamma, both of which would result in improved insulin sensitivity. CB1-/- mice were obtained from A. Zimmer (University of Bonn) (Zimmer et al., 1999) and back-crossed onto C57BL/6J genetic background for ten generations by A. Zimmer before homozygous CB1-/- mice were re-derived at Taconic Farms (German Town, NY) onto the C57BL/6N genetic background. Male CB1-/- mice and control littermates (n=5-7 in each group) at 2 months of age were fed with regular chow (Teklad 7012, 13 % kcal from fat, 3.41 kcal/g, Harlan Laboratories, Indianapolis, IN, USA) or high fat diet (S3282, 59.4% kcal from fat; 24.5% kcal from carbohydrate; 16.2% kcal from protein; 5.29 kcal/g, Bio-Serv, Frenchtown, NJ, USA) for 14 weeks, and were individually caged 1 week before drug treatment. Vehicle (0.5% methylcellulose) or AM251 (10 mg/kg, Sigma, St Louis, MO, USA) were dosed by oral gavage at 5:00 PM daily for 2 days. Body weight was measured at 5:00 PM on day 1 and 2, and at 10:00 AM on day 3 before tissue collection. Food was measured at 5:00 PM on day 1 and at 10:00 AM on day 3 before tissue collection. Food intake is calculated as the difference in food weight at the start minus at the end of the study. Mice were euthanized by CO2 asphyxiation at 10:00 AM following the second dose.