Human milk derived peptide AOPDM1 attenuates obesity by restricting adipogenic differentiation through MAPK signalling.

BACKGROUND: Emerging evidence revealed peptides within breast milk may be an abundant source of potential candidates for metabolism regulation. Our previous work identified numerous peptides existed in breast milk, but its function has not been validated. Thus, our study aims to screen for novel peptides that have the potential to antagonize obesity and diabetes. METHODS: A function screen was designed to identify the candidate peptide and then the peptide effect was validated by assessing lipid storage. Afterwards, the in vivo study was performed in two obese models: high-fat diet (HFD)-induced obese mice and obese ob/ob mice. For mechanism study, a RNA-seq analysis was conducted to explore the pathway that account for the biological function of peptide. RESULTS: By performing a small scale screening, a peptide (AVPVQALLLNQ) termed AOPDM1 (anti-obesity peptide derived from breast milk 1) was identified to reduce lipid storage in adipocytes. Further study showed AOPDM1 suppressed adipocyte differentiation by sustaining ERK activity at later stage of differentiation which down-regulated PPARγ expression. In vivo, AOPDM1 effectively reduced fat mass and improved glucose metabolism in high-fat diet (HFD)-induced obese mice and obese ob/ob mice. CONCLUSIONS: We identified a novel peptide AOPDM1 derived from breast milk could restrict adipocyte differentiation and ameliorate obesity through regulating MAPK pathway. GENERAL SIGNIFICANCE: Our findings may provide a potential candidate for the discovery of therapeutic drugs for obesity and type 2 diabetes.

Flavonoid-alkylphospholipid conjugates elicit dual inhibition of cancer cell growth and lipid accumulation.

Cancer development is often associated with lipid metabolic reprogramming, including aberrant lipid accumulation. We create novel paradigms endowed with dual functions of anticancer activity and inhibition of lipid accumulation by conjugating the natural product quercetin and synthetic alkylphospholipid drugs, and harnessing the biomedical effects of both. These conjugates offer fresh perspectives in the search for anticancer candidates.

Rational Design of Hybrid Peptides: A Novel Drug Design Approach.

Peptides play crucial roles in various physiological and pathological processes. Consequently, the investigation of peptide-based drugs is a highlight in the research and development of new drugs. However, natural peptides are not always ideal choices for clinical application due to their limited number and sometimes cytotoxicity to normal cells. Aiming to gain stronger or specific or novel biological effects and overcome the disadvantages of natural peptides, artificial hybrid peptides have been designed by combining the sequence of two or more different peptides with varied biological functions. Compared to natural peptides, hybrid peptides have shown better therapeutic potentials against bacteria, tumors, and metabolic diseases. In this review, design strategies, structure features and recent development of hybrid peptides are summarized; future directions for the research and development of hybrid peptide drugs are also discussed.

Novel Tetrahydroquinazolinamines as Selective Histamine 3 Receptor Antagonists for the Treatment of Obesity.

The histamine 3 receptor (H3R) is a presynaptic receptor, which modulates several neurotransmitters including histamine and various essential physiological processes, such as feeding, arousal, cognition, and pain. The H3R is considered as a drug target for the treatment of several central nervous system disorders. We have synthesized and identified a novel series of 4-aryl-6-methyl-5,6,7,8-tetrahydroquinazolinamines that act as selective H3R antagonists. Among all the synthesized compounds, in vitro and docking studies suggested that the 4-methoxy-phenyl-substituted tetrahydroquinazolinamine compound 4c has potent and selective H3R antagonist activity (IC50 < 0.04 µM). Compound 4c did not exhibit any activity on the hERG ion channel and pan-assay interference compounds liability. Pharmacokinetic studies showed that 4c crosses the blood brain barrier, and in vivo studies demonstrated that 4c induces anorexia and weight loss in obese, but not in lean mice. These data reveal the therapeutic potential of 4c as an anti-obesity candidate drug via antagonizing the H3R.

Are peptide conjugates the golden therapy against obesity?

Obesity is a worldwide pandemic, which can be fatal for the most extremely affected individuals. Lifestyle interventions such as diet and exercise are largely ineffective and current anti-obesity medications offer little in the way of significant or sustained weight loss. Bariatric surgery is effective, but largely restricted to only a small subset of extremely obese patients. While the hormonal factors mediating sustained weight loss and remission of diabetes by bariatric surgery remain elusive, a new class of polypharmacological drugs shows potential to shrink the gap in efficacy between a surgery and pharmacology. In essence, this new class of drugs combines the beneficial effects of several independent hormones into a single entity, thereby combining their metabolic efficacy to improve systems metabolism. Such unimolecular drugs include single molecules with agonism at the receptors for glucagon, glucagon-like peptide 1 and the glucose-dependent insulinotropic polypeptide. In preclinical studies, these specially tailored multiagonists outperform both their mono-agonist components and current best in class anti-obesity medications. While clinical trials and vigorous safety analyses are ongoing, these drugs are poised to have a transformative effect in anti-obesity therapy and might hopefully lead the way to a new era in weight-loss pharmacology.

The Synthetic and Biological Attributes of Pyrazole Derivatives: A Review.

Pyrazole nucleus is a unique structural scaffold which acts as an interesting template for combinatorial as well as medicinal chemistry. This review presents a detailed overview on the synthesis, QSAR and pharmacological applications of pyrazole. In addition, it covers most recent reports on structural modifications on pyrazole illustrating vital structural activity relationship.

Inhibition of Adipogenesis by Thiourea Derivatives.

BACKGROUND: Obesity is one of the major health problems with inherent risk of type 2 diabetes, hypertension, CVDs, etc. Adipogenesis is a major contributor in the process of obesity. Inhibition of adipocytes differentiation is one of the key approaches to treat obesity. OBJECTIVE: To discover the new inhibitors of adipogenesis as the treatment for obesity. METHOD: We describe here, the synthesis, and anti-adipogenic activity of thiourea derivatives 1-14. These derivatives were synthesized by the reactions of phenyl and pentafluorophenyl isothiocyanate with different aromatic amines. Pure compounds 1-14 were evaluated for their in vitro antiadipogenesis activity employing 3T3-L1 cells lines. RESULTS: Compounds 1-3, 5-9, and 11-14 significantly inhibited the pre-adipocyte differentiation into adipocytes, which was measured by staining the cells, and through morphological examination. Compound 10 (1-(4"-Chlorophenyl)-3-(pentafluorophenyl)-thiourea) showed a potent inhibition of adipocyte differentiation with IC50 = 740.00 ± 2.36 nM, which was more potent than the standards, epigallocatechin gallate (IC50 = 16.73 ± 1.34 µM), and curcumin (IC50 = 18.62 ± 0.74 µM). All other compounds showed a moderate to weak anti-adipogenesis activity. Compounds 1- 14 were also evaluated for their cytotoxicity. Compounds 3, 10, and 14 showed some toxicity to the cancer cell lines, while compounds 2, 3, 10, 12, and 14 showed a moderate to weak cytotoxicity against the normal cell lines. CONCLUSION: All the compounds reported in this paper are known, except compound 11. They have been identified as new inhibitors of Adipogenesis. Adipogenesis is the process of adipocytes differentiation from pre-adipocytes. This extensively studied model of cell diff differentiation. Further synthetic modifications, and optimization of anti-adipogenic activity may lead to the development of anti-obesity agents.

Pharmacological Inhibition of Monoacylglycerol O-Acyltransferase 2 Improves Hyperlipidemia, Obesity, and Diabetes by Change in Intestinal Fat Utilization.

Monoacylglycerol O-acyltransferase 2 (MGAT2) catalyzes the synthesis of diacylglycerol (DG), a triacylglycerol precursor and potential peripheral target for novel anti-obesity therapeutics. High-throughput screening identified lead compounds with MGAT2 inhibitory activity. Through structural modification, a potent, selective, and orally bioavailable MGAT2 inhibitor, compound A (compA), was discovered. CompA dose-dependently inhibited postprandial increases in plasma triglyceride (TG) levels. Metabolic flux analysis revealed that compA inhibited triglyceride/diacylglycerol resynthesis in the small intestine and increased free fatty acid and acyl-carnitine with shorter acyl chains than originally labelled fatty acid. CompA decreased high-fat diet (HFD) intake in C57BL/6J mice. MGAT2-null mice showed a similar phenotype as compA-treated mice and compA did not suppress a food intake in MGAT2 KO mice, indicating that the anorectic effects were dependent on MGAT2 inhibition. Chronic administration of compA significantly prevented body weight gain and fat accumulation in mice fed HFD. MGAT2 inhibition by CompA under severe diabetes ameliorated hyperglycemia and fatty liver in HFD-streptozotocin (STZ)-treated mice. Homeostatic model assessments (HOMA-IR) revealed that compA treatment significantly improved insulin sensitivity. The proximal half of the small intestine displayed weight gain following compA treatment. A similar phenomenon has been observed in Roux-en-Y gastric bypass-treated animals and some studies have reported that this intestinal remodeling is essential to the anti-diabetic effects of bariatric surgery. These results clearly demonstrated that MGAT2 inhibition improved dyslipidemia, obesity, and diabetes, suggesting that compA is an effective therapeutic for obesity-related metabolic disorders.

Synthesis and evaluation of anticancer and antiobesity activity of 1-ethoxy carbonyl-3,5-bis (3'-indolyl methylene)-4-pyperidone analogs.

A series of eleven novel bisindole derivatives were synthesized and screened for anticancer and antiobesity potentials in in vitro mode. The reaction of 1-ethoxy carbonyl 4-pyperidone 1a with indole-3-carboxaldehyde 1b in presence of catalytic amount of piperidine gave 2 which was N-alkylated with different benzyl halides in the presence of potassium carbonate to afford compounds 3a-3k in quantitative yields. Among the compounds tested for anticancer activity against different human cancer cell lines, 3f significantly inhibited HepG2 cell line (IC50 7.33 µM) when compared with standard doxorubicin (IC50 10.15 µM). Compounds 3e (IC50 2.75 µM), 3f (IC50 4.21 µM) and 3i (IC50 15.98 µM) showed better activity than the standard curcumin (IC50 23.54 µM) against A549 cell line. Also, among the synthesized compounds, 3g (IC50 14.89 µM), 3c (IC50 56.41 µM) and 3i (IC50 30.88 µM) have potentially inhibited enzyme lipase when compared to standard Orlistat (IC50 62.25 µM). In in silico docking assays, piperidones 3e, 3f, 3i, 3c and 3a showed higher binding affinity towards anti-cancer target of A549 (3e: -11.1, 3f: -10.3, 3c: -11.3, 3i: -11.2 kcal/mol), HepG2 (3f: -10.5 kcal/mol), HeLa (3d: -10.0 kcal/mol) and SKOV3 (3f: -8.4 kcal/mol) cell lines better than standard drug doxorubicin. Docking to lipase protein for compounds 3i, 3g and 3c showed scores of -11.1, -10.7 and -10.5 kcal/mol when compared to that of standard drug Orlistat with -6.9 kcal/mol.

Synthesis and Biological Evaluation of Novel Bouchardatine Derivatives as Potential Adipogenesis/Lipogenesis Inhibitors for Antiobesity Treatment.

Our recent study has shown that the natural product bouchardatine (1) can reduce the triglyceride (TG) content in 3T3-L1 adipocytes (EC50 ≈ 25 µM). Here, we synthesized two series of compounds by introducing amine side chains at the 5 or 8 position of 1 and evaluated the lipid-lowering activity of derivatives. It was found that some of the compounds had significant lipid-lowering effects, and the most active compound 3d showed better activity (EC50 = 0.017 µM) than 2 (EC50 = 0.086 µM), a compound reported by us. Further, the mechanism studies revealed that 3d blocked TG accumulation via activation of the LKB1-AMPK signaling pathway, efficiently down-regulating the expression of key regulators of adipogenesis/lipogenesis. Cell uptake assay and confocal imaging of 3d in cells indicated that compound 3d had favorable cell permeability. Our results suggest that 3d may be a promising agent for the treatment of obesity and related metabolic disorders.

Mitochondrial ADP/ATP exchange inhibition: a novel off-target mechanism underlying ibipinabant-induced myotoxicity.

Cannabinoid receptor 1 (CB1R) antagonists appear to be promising drugs for the treatment of obesity, however, serious side effects have hampered their clinical application. Rimonabant, the first in class CB1R antagonist, was withdrawn from the market because of psychiatric side effects. This has led to the search for more peripherally restricted CB1R antagonists, one of which is ibipinabant. However, this 3,4-diarylpyrazoline derivative showed muscle toxicity in a pre-clinical dog study with mitochondrial dysfunction. Here, we studied the molecular mechanism by which ibipinabant induces mitochondrial toxicity. We observed a strong cytotoxic potency of ibipinabant in C2C12 myoblasts. Functional characterization of mitochondria revealed increased cellular reactive oxygen species generation and a decreased ATP production capacity, without effects on the catalytic activities of mitochondrial enzyme complexes I-V or the complex specific-driven oxygen consumption. Using in silico off-target prediction modelling, combined with in vitro validation in isolated mitochondria and mitoplasts, we identified adenine nucleotide translocase (ANT)-dependent mitochondrial ADP/ATP exchange as a novel molecular mechanism underlying ibipinabant-induced toxicity. Minor structural modification of ibipinabant could abolish ANT inhibition leading to a decreased cytotoxic potency, as observed with the ibipinabant derivative CB23. Our results will be instrumental in the development of new types of safer CB1R antagonists.

Casitas B-Lineage Lymphoma RING Domain Inhibitors Protect Mice against High-Fat Diet-Induced Obesity and Insulin Resistance.

The casitas b-lineage lymphoma (c-Cbl) is an important adaptor protein with an intrinsic E3 ubiquitin ligase activity that interacts with E2 proteins such as UbCH7. c-Cbl plays a vital role in regulating receptor tyrosine kinase signaling. c-Cbl involves in whole-body energy homeostasis, which makes it a potential target for the treatment of type 2 diabetes and obesity. In the present study, we have designed two parental peptides and 55 modified peptides based on the structure of UbCH7 loop L1 and L2. Thirteen of the modified peptides showed increased inhibitory activity in a fluorescence polarization-based assay. In the in vivo proof of study principle, mice treated with peptides 10, 34, 49 and 51 were protected against high-fat diet-induced obesity and insulin resistant. These inhibitors may potentially lead to new therapeutic alternatives for obesity and type 2 diabetes.

Design, synthesis and evaluation of MCH receptor 1 antagonists--Part III: Discovery of pre-clinical development candidate BI 186908.

Although overweight and obesity are highly prevalent conditions, options to treat them are still very limited. As part of our search for safe and effective MCH-R1 antagonists for the treatment of obesity, two series of pyridones and pyridazinones were evaluated. Optimization was aimed at improving DMPK properties by increasing metabolic stability and improving the safety profile by reducing inhibition of the hERG channel and reducing the potential to induce phospholipidosis. Steric shielding of a labile keto moiety with an ortho-methyl group and fine-tuning of the polarity in several parts of the molecule resulted in BI 186908 (11 g), a potent and selective MCH-R1 antagonist with favorable DMPK and CMC properties. Chronic administration of BI 186908 resulted in significant body weight reduction comparable to sibutramine in a 4 week diet-induced obesity model in rats. Based on its favorable safety profile, BI 186908 was advanced to pre-clinical development.

Design, synthesis and evaluation of MCH receptor 1 antagonists--Part II: Optimization of pyridazines toward reduced phospholipidosis and hERG inhibition.

Despite recent success there remains a high therapeutic need for the development of drugs targeting diseases associated with the metabolic syndrome. As part of our search for safe and effective MCH-R1 antagonists for the treatment of obesity, a series of 3,6-disubstituted pyridazines was evaluated. During optimization several issues of the initial lead structures had to be resolved, such as selectivity over related GPCRs, inhibition of the hERG channel as well as the potential to induce phospholipidosis. Utilizing property-based design, we could demonstrate that all parameters can significantly be improved by consequently increasing the polarity of the compounds. By this strategy, we succeeded in identifying potent and orally available MCH-R1 antagonists with good selectivity over M1 and 5-HT2A and an improved safety profile with respect to hERG inhibition and phospholipidosis.

Inhibitory effects of hydroxylated cinnamoyl esters on lipid absorption and accumulation.

Obesity is a risk factor associated with several lifestyle-related diseases, for example, diabetes, high blood pressure, hyperlipidemia and cancer. Caffeic acid 2-phenylethyl ester (CAPE, 1), a naturally-occurring compound found in various plants and propolis, which exhibits anti-inflammatory, immunomodulatory and cytotoxic activities and inhibits 3T3-L1 differentiation to adipocytes. As part of our efforts to moderate lifestyle-related diseases, we synthesized analogs of 1 and studied their effects on pancreatic lipase activities, lipid absorption, and 3T3-L1 differentiation. We found that catechols 1-4 show inhibitory activities against pancreatic lipase in a dose-dependent manner in vitro. Compounds 1-3 proved to be more potent inhibitors of pancreatic lipase than 5, 6, 8, and 9, which have one hydroxyl group, respectively. Compound 7 has three aromatic hydroxyl groups and restrains greater lipase inhibitory activity than the other compounds. In addition, 7 and 3 significantly suppress a rise in blood triglyceride (TG) levels in mice given corn oil orally. Furthermore, 2 and 3 are more potent at preventing 3T3-L1 differentiation (lipid accumulation) than 1, while 7 is more potent than 3, 8, and 9 in these assays. Compounds 2, 3, and 7 inhibit lipid absorption and accumulation, with new compound 7 being the most potent. These results indicate that 7 may have potential benefits as a health agent with anti-obesity properties.

Position and length of fatty acids strongly affect receptor selectivity pattern of human pancreatic polypeptide analogues.

Pancreatic polypeptide (PP) is a satiety-inducing gut hormone targeting predominantly the Y4 receptor within the neuropeptide Y multiligand/multireceptor family. Palmitoylated PP-based ligands have already been reported to exert prolonged satiety-inducing effects in animal models. Here, we suggest that other lipidation sites and different fatty acid chain lengths may affect receptor selectivity and metabolic stability. Activity tests revealed significantly enhanced potency of long fatty acid conjugates on all four Y receptors with a preference of position 22 over 30 at Y1 , Y2 and Y5 receptors. Improved Y receptor selectivity was observed for two short fatty acid analogues. Moreover, [K(30)(E-Prop)]hPP2-36 (15) displayed enhanced stability in blood plasma and liver homogenates. Thus, short chain lipidation of hPP at key residue 30 is a promising approach for anti-obesity therapy because of maintained selectivity and a sixfold increased plasma half-life.

Antiobesity, antioxidant and cytotoxicity activities of newly synthesized chalcone derivatives and their metal complexes.

Four sets of rationally designed chalcones were prepared for evaluation of their antiobesity, antioxidant and cytotoxicity activities. These sets include nine oleoyl chalcones as mimics of oleoyl estrone, three monohydroxy chalcones (chalcone ligands), Schiff base-derived chalcones and four copper as well as zinc complexes. Oleoyl chalcones 4d, 4e and particularly 6a as an isosteric isomer of oleoyl estrone, were as active as Orlistat on weight loss and related metabolic parameters using male SD rats in vivo. Chalcone ligands 10a-c and Schiff base-derived chalcones 11 and 14a,b were weakly antioxidants, while, the copper and zinc complexes 15a-d were good antioxidants with zinc chelates 15b,d being more active than their copper analogues 15a,cin vitro. Compounds 10c and 14a showed good cytotoxicity activities as Doxorubicin against PC3 cancer cell line in vitro, while, the copper complex 15c showed promising activity with IC50 value of 5.95 µM. The estimated IC50 value for Doxorubicin was 8.7 µM. Chalcones 14a,b are bifunctional probes for potential investigations in cancer diagnosis and radiotherapy by complexation with Gd(3+) or metal radioisotopes followed by posttranslation of Shiga toxin B-subunits that target globotriosyl ceramide expressing cancer cells.

Translational issues in targeting brown adipose tissue thermogenesis for human obesity management.

The recent advancements in unraveling novel mechanisms that control the induction, (trans)differentiation, proliferation, and thermogenic activity and capacity of brown adipose tissue (BAT), together with the application of imaging techniques for human BAT visualization, have generated optimism that these advances will provide novel strategies for targeting BAT thermogenesis, leading to efficacious and safe obesity therapies. This paper first provides an overview of landmark events of the past few decades that have been driving the search for pharmaceutical and nutraceutical compounds that would increase BAT thermogenesis for obesity management. It then addresses issues about what could be expected from an ideal thermogenic antiobesity approach, in particular to what extent daily energy expenditure will need to increase in order to achieve long-term weight loss currently achievable only through bariatric surgery, and whether the human body will have enough thermogenic capacity to reach this target weight loss by future therapies focused on BAT.

Synthesis and carbonic anhydrase inhibitory properties of sulfamides structurally related to dopamine.

A series of novel sulfamides incorporating the dopamine scaffold were synthesized. Reaction of amines and tert-butyl-alcohol/benzyl alcohol in the presence of chlorosulfonyl isocyanate (CSI) afforded sulfamoyl carbamates, which were converted to the title compounds by treatment with trifluoroacetic acid or by palladium-catalyzed hydrogenolysis. Inhibition of six α-carbonic anhydrases (CAs, EC 4.2.1.1), that is, CA I, CA II, CA VA, CA IX, CA XII and CA XIV, and two ß-CAs from Candida glabrata (CgCA) and Mycobacterium tuberculosis (Rv3588) with these sulfamides was investigated. All CA isozymes were inhibited in the low micromolar to nanomolar range by the dopamine sulfamide analogues. K(i)s were in the range of 0.061-1.822 µM for CA I, 1.47-2.94 nM for CA II, 2.25-3.34 µM for CA VA, 0.041-0.37 µM for CA IX, 0.021-1.52 µM for CA XII, 0.007-0.219 µM for CA XIV, 0.35-5.31 µM for CgCA and 0.465-4.29 µM for Rv3588. The synthesized sulfamides may lead to inhibitors targeting medicinally relevant CA isoforms with potential applications as antiepileptic, antiobesity antitumor agents or anti-infective.

Fibroblast growth factor 21 mediates specific glucagon actions.

Glucagon, an essential regulator of glucose homeostasis, also modulates lipid metabolism and promotes weight loss, as reflected by the wasting observed in glucagonoma patients. Recently, coagonist peptides that include glucagon agonism have emerged as promising therapeutic candidates for the treatment of obesity and diabetes. We developed a novel stable and soluble glucagon receptor (GcgR) agonist, which allowed for in vivo dissection of glucagon action. As expected, chronic GcgR agonism in mice resulted in hyperglycemia and lower body fat and plasma cholesterol. Notably, GcgR activation also raised hepatic expression and circulating levels of fibroblast growth factor 21 (FGF21). This effect was retained in isolated primary hepatocytes from wild-type (WT) mice, but not GcgR knockout mice. We confirmed this link in healthy human volunteers, where injection of natural glucagon increased plasma FGF21 within hours. Functional relevance was evidenced in mice with genetic deletion of FGF21, where GcgR activation failed to induce the body weight loss and lipid metabolism changes observed in WT mice. Taken together, these data reveal for the first time that glucagon controls glucose, energy, and lipid metabolism at least in part via FGF21-dependent pathways.