A novel peripheral cannabinoid 1 receptor antagonist, AJ5012, improves metabolic outcomes and suppresses adipose tissue inflammation in obese mice.

The overactivity of cannabinoid 1 receptor (CB1R) is associated with obesity and type 2 diabetes. First-generation CB1R antagonists, such as rimonabant, offered therapeutic advantages for the control of obesity and related metabolic abnormalities, but their therapeutic potential was limited by undesirable neuropsychiatric side effects. Here, we evaluated AJ5012 as a novel potent peripheral CB1R antagonist and, using this antagonist, investigated the role of peripheral CB1R on adipose tissue inflammation in obese mouse models. AJ5012 had a high degree of CB1R and cannabinoid 2 receptor selectivity but a low brain:plasma concentration ratio without eliciting centrally mediated neurobehavioral effects. In diet-induced obese (DIO) mice, AJ5012 did not reduce food intake but did induce a significant weight loss, likely owing to an increased energy expenditure. It was as effective as rimonabant for the improvement of hormonal or metabolic abnormalities, glycemic control, and insulin sensitivity. The treatment of DIO and leptin receptor-deficient mice with AJ5012 also exhibited effects comparable to rimonabant for the prevention of macrophage infiltration, activation of the nucleotide-binding domain and leucine-rich repeat protein 3 inflammasome, and production of proinflammatory cytokines, which resulted in the suppression of adipose tissue inflammation. In addition to macrophage, activation of CB1R in 3T3-L1 adipocytes induced the expression of proinflammatory genes, which was fully inhibited by AJ5012. Our findings identified AJ5012 as a novel peripheral CB1R antagonist and suggest that peripheral CB1R blockade might break the links between insulin resistance and adipose tissue inflammation.-Han, J. H., Shin, H., Park, J.-Y., Rho, J. G., Son, D. H., Kim, K. W., Seong, J. K., Yoon, S.-H., Kim, W. A novel peripheral cannabinoid 1 receptor antagonist, AJ5012, improves metabolic outcomes and suppresses adipose tissue inflammation in obese mice.

A Novel Peptide, Nicotinyl⁻Isoleucine⁻Valine⁻Histidine (NA⁻IVH), Promotes Antioxidant Gene Expression and Wound Healing in HaCaT Cells.

Nicotinamide (NA), a water-soluble vitamin B3, has been shown to exert cellular-protective effects against reactive oxygen species (ROS). In order to improve the cellular-protective effects of NA, we synthesized a novel compound, nicotinyl⁻isoleucine⁻valine⁻histidine (NA⁻IVH), by combining NA with jellyfish peptides' IVH. In the present study, we examined the cellular-protective effects of the novel synthetic nicotinyl-peptide, NA⁻IVH. We found that NA⁻IVH enhances the radical scavenging activity with a robust increase of the nuclear factor (erythroid-derived 2)-like factor (Nrf2) expression in human HaCaT keratinocytes. In addition, NA⁻IVH protected the cells from hydrogen peroxide (H2O2)-induced cell death. Interestingly, NA⁻IVH exhibited an improved wound-healing effect in a high glucose condition, possibly through the regulation of reactive oxygen species (ROS). Collectively, our results imply that a novel nicotinyl-peptide, NA⁻IVH, has a wound-healing effect in a hyperglycemic condition, possibly by modulating excessive ROS.

Gallic Acid Promotes Wound Healing in Normal and Hyperglucidic Conditions.

Skin is the outermost layer of the human body that is constantly exposed to environmental stressors, such as UV radiation and toxic chemicals, and is susceptible to mechanical wounding and injury. The ability of the skin to repair injuries is paramount for survival and it is disrupted in a spectrum of disorders leading to skin pathologies. Diabetic patients often suffer from chronic, impaired wound healing, which facilitate bacterial infections and necessitate amputation. Here, we studied the effects of gallic acid (GA, 3,4,5-trihydroxybenzoic acid; a plant-derived polyphenolic compound) on would healing in normal and hyperglucidic conditions, to mimic diabetes, in human keratinocytes and fibroblasts. Our study reveals that GA is a potential antioxidant that directly upregulates the expression of antioxidant genes. In addition, GA accelerated cell migration of keratinocytes and fibroblasts in both normal and hyperglucidic conditions. Further, GA treatment activated factors known to be hallmarks of wound healing, such as focal adhesion kinases (FAK), c-Jun N-terminal kinases (JNK), and extracellular signal-regulated kinases (Erk), underpinning the beneficial role of GA in wound repair. Therefore, our results demonstrate that GA might be a viable wound healing agent and a potential intervention to treat wounds resulting from metabolic complications.

FoxO1 regulates leptin-induced mood behavior by targeting tyrosine hydroxylase.

PURPOSE: While leptin has been associated with various psycho-physiological functions, the molecular network in leptin-mediated mood regulation remains elusive. METHODS: Anxiolytic behaviors and tyrosine hydroxylase (TH) levels were examined after leptin administration. Functional roles of STAT3 and FoxO1 in regulation of TH expression were investigated using in vivo and in vitro systems. A series of animal behavioral tests using dopaminergic neuron-specific FoxO1 KO (FoxO1 KODAT) were performed and investigated the roles of FoxO1 in regulation of mood behaviors. RESULTS: Here, we show that administration of leptin induces anxiolytic-like phenotype through the activation of signal transducer and activator of transcription 3 (STAT3) and the inhibition of forkhead box protein O1 (FoxO1) in dopaminergic (DA) neurons of the midbrain. Specifically, STAT3 and FoxO1 directly bind to and exert opposing effects on tyrosine hydroxylase (TH) expression, where STAT3 acts as an enhancer and FoxO1 acts as a prominent repressor. Accordingly, suppression of the prominent suppressor FoxO1 by leptin strongly increased TH expression. Furthermore, our previous results showed that specific deletion of FoxO1 in DA neurons (FoxO1 KODAT) led to a profound elevation of TH activity and dopamine contents. Finally, FoxO1 KODAT mice exhibited enhanced leptin sensitivity as well as displayed reduced anxiety- and depression-like behaviors. CONCLUSIONS: This work establishes a novel molecular mechanism of mood behavior regulation by leptin and suggests FoxO1 suppression by leptin might be a key for leptin-induced behavioral manifestation in DA neurons.