Investigational PPAR-gamma agonists for the treatment of Type 2 diabetes

Prospective de novo drug design with deep interactome learning

De novo drug design aims to generate molecules from scratch that possess specific chemical and pharmacological properties. We present a computational approach utilizing interactome-based deep learning for ligand- and structure-based generation of drug-like molecules. This method capitalizes on the unique strengths of both graph neural networks and chemical language models, offering an alternative to the need for application-specific reinforcement, transfer, or few-shot learning. It enables the "zero-shot" construction of compound libraries tailored to possess specific bioactivity, synthesizability, and structural novelty. In order to proactively evaluate the deep interactome learning framework for protein structure-based drug design, potential new ligands targeting the binding site of the human peroxisome proliferator-activated receptor (PPAR) subtype gamma are generated. The top-ranking designs are chemically synthesized and computationally, biophysically, and biochemically characterized. Potent PPAR partial agonists are identified, demonstrating favorable activity and the desired selectivity profiles for both nuclear receptors and off-target interactions. Crystal structure determination of the ligand-receptor complex confirms the anticipated binding mode. This successful outcome positively advocates interactome-based de novo design for application in bioorganic and medicinal chemistry, enabling the creation of innovative bioactive molecules.

Scintillation Proximity Assay (SPA)-Based Radioligand Binding for PPARα, PPARγ, and PPARδ Receptors

Peroxisome proliferator-activated receptors (PPARs) have been exploited as drug targets for combating multiple diseases. Several activators with different selectivity for the PPAR α, γ, and δ subtypes have been introduced into the market or have reached advanced clinical trials. Binding assays are of utmost importance for the discovery and profiling of such PPAR ligands. Binding assays are often based on radioligands, in particular, tritiated molecules are applied. We developed synthetic procedures for tritiating various PPAR agonists and applied these radioligands for setting up a scintillation proximity assay (SPA) for PPAR α, γ, and δ. These SPAs allow to assess the binding affinities of PPAR α, γ, and δ ligands, along with their respective subtype selectivity profiles. Therefore, SPA is an important tool for hit discovery and lead optimization campaigns aimed at identifying next-generation PPAR ligands.

Further evidence for the involvement of the PPARγ system on alcohol intake and sensitivity in rodents

RATIONALE

Peroxisome Proliferator Activator receptors (PPARs) are intracellular receptors that function as transcription factors, which regulate specific metabolic and inflammatory processes. PPARs are broadly distributed in the body and are also expressed in the central nervous system, especially in areas involved in addiction-related behavioral responses. Recent studies support a role of PPARs in alcoholism and pioglitazone: a PPARγ agonist used for treatment of type 2 diabetes showed efficacy in reducing alcohol drinking, stress-induced relapse, and alcohol withdrawal syndrome in rats.

OBJECTIVES AND METHODS

In the current work, we tested the pharmacological effects of pioglitazone on binge-like alcohol consumption using an intermittent two-bottle choice paradigm in Wistar rats and on the "drinking in the dark" (DID) model in mice with selective deletion of PPARγ in neurons.

RESULTS

Our data show that repeated administration of pioglitazone (10, 30 mg/kg) reduces high voluntary alcohol consumption in Wistar rats. Pre-treatment with the selective PPARγ antagonist GW9662 (5 mg/kg) completely prevented the effect of pioglitazone, demonstrating that its action is specifically mediated by activation of PPARγ. In line with this result, repeated administration of pioglitazone (30 mg/kg) attenuated binge alcohol consumption in PPARγ^(+/+) mice. Whereas in PPARγ^(-/-) mice, which exhibit reduced alcohol consumption, pioglitazone had no effect. Of note, PPARγ^(-/-) mice exhibited lower patterns of alcohol drinking without showing difference in sucrose (control) intake. Interestingly, PPARγ^(-/-) mice displayed a higher sensitivity to the sedative and ataxic effect of alcohol compared with their wild-type counterpart.

CONCLUSIONS

Collectively, these data suggest that PPARγ agonists, and specifically pioglitazone, could be potential therapeutics for the treatment of binge alcohol drinking.

Administration of Fenofibrate Markedly Elevates Fabp3 in Rat Liver and Plasma and Confounds Its Use as a Preclinical Biomarker of Cardiac and Muscle Toxicity

Proteins involved in lipid homeostasis are often regulated through the nuclear peroxisome proliferator-activated receptors (PPAR). PPARα is the target for the fibrate-class of drugs. Fenofibrate has been approved for its lipid-lowering effects in patients with hypercholesterolemia and hypertriglyceridemia. We were interested in understanding the expression of the energy transporters in energy-utilizing tissues like liver, heart, muscle, and adipose tissues in rat with the hypothesis that the change in transporter expression would align with the known lipid-lowering effects of PPARα agonists like fenofibrate. We found that several fatty-acid transporter proteins had significantly altered levels following 8 days of fenofibrate dosing. The mRNA levels of the highly abundant Fatp2 and Fatp5 in rat liver increased approximately twofold and decreased fourfold, respectively. Several fatty-acid-binding proteins and acyl-CoA-binding proteins had a significant increase in mRNA abundance but not the major liver fatty-acid-binding protein, Fabp1. Of particular interest was the increased liver expression of Fabp3 also known as heart-fatty acid binding protein (H-FABP or FABP3). FABP3 has been proposed as a circulating clinical biomarker for cardiomyopathy and muscle toxicity, as well as a preclinical marker for PPARα-induced muscle toxicity. Here, we show that fenofibrate induces liver mRNA levels of Fabp3 ~5000-fold resulting in an approximately 50-fold increase in FABP3 protein levels in the whole liver. This increased liver expression complicates the interpretation and potential use of FABP3 as a specific biomarker for PPARα-induced muscle toxicities.

Metabolic and hepatic effects of liraglutide, obeticholic acid and elafibranor in diet-induced obese mouse models of biopsy-confirmed nonalcoholic steatohepatitis

AIM

To evaluate the pharmacodynamics of compounds in clinical development for nonalcoholic steatohepatitis (NASH) in obese mouse models of biopsy-confirmed NASH.

METHODS

Male wild-type C57BL/6J mice (DIO-NASH) and Lep^ob/ob (ob/ob-NASH) mice were fed a diet high in trans-fat (40%), fructose (20%) and cholesterol (2%) for 30 and 21 wk, respectively. Prior to treatment, all mice underwent liver biopsy for confirmation and stratification of liver steatosis and fibrosis, using the nonalcoholic fatty liver disease activity score (NAS) and fibrosis staging system. The mice were kept on the diet and received vehicle, liraglutide (0.2 mg/kg, SC, BID), obeticholic acid (OCA, 30 mg/kg PO, QD), or elafibranor (30 mg/kg PO, QD) for eight weeks. Within-subject comparisons were performed on changes in steatosis, inflammation, ballooning degeneration, and fibrosis scores. In addition, compound effects were evaluated by quantitative liver histology, including percent fractional area of liver fat, galectin-3, and collagen 1a1.

RESULTS

Liraglutide and elafibranor, but not OCA, reduced body weight in both models. Liraglutide improved steatosis scores in DIO-NASH mice only. Elafibranor and OCA reduced histopathological scores of hepatic steatosis and inflammation in both models, but only elafibranor reduced fibrosis severity. Liraglutide and OCA reduced total liver fat, collagen 1a1, and galectin-3 content, driven by significant reductions in liver weight. The individual drug effects on NASH histological endpoints were supported by global gene expression (RNA sequencing) and liver lipid biochemistry.

CONCLUSION

DIO-NASH and ob/ob-NASH mouse models show distinct treatment effects of liraglutide, OCA, and elafibranor, being in general agreement with corresponding findings in clinical trials for NASH. The present data therefore further supports the clinical translatability and utility of DIO-NASH and ob/ob-NASH mouse models of NASH for probing the therapeutic efficacy of compounds in preclinical drug development for NASH.

Effects of Flavonoids and Triterpene Analogues from Leaves of Eleutherococcus sieboldianus (Makino) Koidz. 'Himeukogi' in 3T3-L1 Preadipocytes

Eleutherococcus sieboldianus (Makino) Koidz. is a local product from the area in and around Yonezawa City in Yamagata Prefecture, Japan. It has been used as a medicinal plant for a long time. We isolated and identified four types of flavonoid glycosides [astragalin (1), isoquercetin (2), rhamnocitrin 3-O-glucoside (3), and nicotiflorin (4)], a triterpene [methyl hederagenin (5)], and three types of triterpene glycosides [δ-hederin (6), echinocystic acid 3-O-arabinoside (7), and cauloside B (8)] from the methanol extract of E. sieboldianus, which regulates lipid accumulation in 3T3-L1 preadipocytes. Among the compounds isolated, 2 and 8 up- and down-regulated lipid accumulation and insulin induced adipocyte differentiation in 3T3-L1 preadipocytes. Compound 2 induced up-regulation of lipid accumulation and decreased adipocyte size, while 8 down-regulated lipid accumulations without decreasing cell size. Additionally, 2 increased adipogenic proteins [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and fatty-acid-binding protein 4 (FABP4)]. In contrast, 8 decreased the levels of all adipogenic proteins and glucose transporter type 4 (GLUT4), but increased adiponectin.

Peroxisome proliferator-activated receptor gamma signaling in human sperm physiology

Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of the PPARs, which are transcription factors of the steroid receptor superfamily. PPARγ acts as an important molecule for regulating energy homeostasis, modulates the hypothalamic-pituitary-gonadal (HPG) axis, and is reciprocally regulated by HPG. In the human, PPARγ protein is highly expressed in ejaculated spermatozoa, implying a possible role of PPARγ signaling in regulating sperm energy dissipation. PPARγ protein is also expressed in Sertoli cells and germ cells (spermatocytes). Its activation can be induced during capacitation and the acrosome reaction. This mini-review will focus on how PPARγ signaling may affect fertility and sperm quality and the potential reversibility of these adverse effects.

Unlock the Thermogenic Potential of Adipose Tissue: Pharmacological Modulation and Implications for Treatment of Diabetes and Obesity

Brown adipose tissue (BAT) is considered an interesting target organ for the treatment of metabolic disease due to its high metabolic capacity. Non-shivering thermogenesis, once activated, can lead to enhanced partitioning and oxidation of fuels in adipose tissues, and reduce the burden of glucose and lipids on other metabolic organs such as liver, pancreas, and skeletal muscle. Sustained long-term activation of BAT may also lead to meaningful bodyweight loss. In this review, we discuss three different drug classes [the thiazolidinedione (TZD) class of PPARγ agonists, β3-adrenergic receptor agonists, and fibroblast growth factor 21 (FGF21) analogs] that have been proposed to regulate BAT and beige recruitment or activation, or both, and which have been tested in both rodent and human. The learnings from these classes suggest that restoration of functional BAT and beige mass as well as improved activation might be required to fully realize the metabolic potential of these tissues. Whether this can be achieved without the undesired cardiovascular side effects exhibited by the TZD PPARγ agonists and β3-adrenergic receptor agonists remains to be resolved.

Nuclear receptors and their selective pharmacologic modulators

Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.

Vitamin D: an overview of its role in skeletal muscle physiology in children and adolescents

Many children may have insufficient serum concentrations of vitamin D, which could prevent optimal muscle development and function. Vitamin D deficiency in animal models results in negative effects on muscle fiber structure and calcium/phosphorus handling, suggesting an integral role of vitamin D in skeletal muscle function. While there is a dearth of data in humans, the available evidence demonstrates a positive association between vitamin D status and muscle function. This review focuses on the important role of vitamin D in muscle function in children and adolescents who live in North American regions where exposure to ultraviolet B radiation is limited and who are thus at increased risk for vitamin D insufficiency. The effects of vitamin D on muscle cell proliferation and differentiation, muscle fiber structure, and calcium and phosphorus handling are discussed. Moreover, the roles of vitamin D and the vitamin D receptor and their genomic and nongenomic actions in muscle function are explored in depth. Future research should aim to establish a vitamin D status consistent with optimal musculoskeletal development and function in young children.

Peroxisome proliferator-activated receptor (PPAR α/γ) agonists as a potential target to reduce cardiovascular risk in diabetes

The disappointing results of glucose lowering studies have highlighted the ongoing need to develop new therapeutic strategies to reduce cardiovascular risk in patients with type 2 diabetes. The presence of a range of metabolic abnormalities in diabetic patients presents a number of potential targets for therapeutic intervention. While modulation of peroxisome proliferator activated receptors (PPARs) represents an attractive approach, the results of studies of pharmacological agonists have been variable. The findings of these studies and rationale for development of dual PPAR-α/γ agonists will be reviewed.

Selective Modulators of PPAR-gamma Activity: Molecular Aspects Related to Obesity and Side-Effects

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a key regulator of lipid metabolism and energy balance implicated in the development of insulin resistance and obesity. The identification of putative natural and synthetic ligands and activators of PPAR-gamma has helped to unravel the molecular basis of its function, including molecular details regarding ligand binding, conformational changes of the receptor, and cofactor binding, leading to the emergence of the concept of selective PPAR-gamma modulators (SPPARgammaMs). SPPARgammaMs bind in distinct manners to the ligand-binding pocket of PPAR-gamma, leading to alternative receptor conformations, differential cofactor recruitment/displacement, differential gene expression, and ultimately differential biological responses. Based on this concept, new and improved antidiabetic agents for the treatment of diabetes are in development. This review summarizes the current knowledge on the mechanism of action and biological effects of recently characterized SPPARgammaMs, including metaglidasen/halofenate, PA-082, and the angiotensin receptor antagonists, recently characterized as a new class of SPPARgammaMs.

Cevoglitazar, a novel peroxisome proliferator-activated receptor-alpha/gamma dual agonist, potently reduces food intake and body weight in obese mice and cynomolgus monkeys

Cevoglitazar is a dual agonist for the peroxisome proliferator-activated receptor (PPAR)-alpha and -gamma subtypes. Dual activation of PPARalpha and -gamma is a therapeutic approach in development for the treatment of type 2 diabetes mellitus and diabetic dyslipidemia. In this report, we show that, in addition to improving insulin sensitivity and lipid metabolism like other dual PPAR agonists, cevoglitazar also elicits beneficial effects on energy homeostasis in two animal models of obesity. In leptin-deficient ob/ob mice, administration of cevoglitazar at 0.5, 1, or 2 mg/kg for 18 d led to acute and sustained, dose-dependent reduction of food intake and body weight. Furthermore, plasma levels of glucose and insulin were normalized after 7 d of cevoglitazar treatment at 0.5 mg/kg. Plasma levels of free fatty acids and triglycerides were dose-dependently reduced. In obese and insulin-resistant cynomolgus monkeys, treatment with cevoglitazar at 50 and 500 mug/kg for 4 wk lowered food intake and body weight in a dose-dependent manner. In these animals, cevoglitazar also reduced fasting plasma insulin and, at the highest dose, reduced hemoglobin A1c levels by 0.4%. These preclinical results demonstrate that cevoglitazar holds promise for the treatment of diabetes and obesity-related disorders because of its unique beneficial effect on energy balance in addition to improving glycemic and metabolic control.

Synthesis and biological activities of novel indole derivatives as potent and selective PPARgamma modulators

Starting from the structure of Telmisartan, a new series of potent and selective PPARgamma modulators was identified. The synthesis, in vitro and in vivo evaluation of the most potent compounds are reported and the X-ray structure of compound 7b bound to the PPARgamma ligand binding domain is described.

Synthesis and evaluation of novel alpha-heteroaryl-phenylpropanoic acid derivatives as PPARalpha/gamma dual agonists

The synthesis of a new series of phenylpropanoic acid derivatives incorporating an heteroaryl group at the alpha-position and their evaluation for binding and activation of PPARalpha and PPARgamma are presented in this report. Among the new compounds, (S)-3-{4-[3-(5-methyl-2-phenyl-oxazol-4-yl)-propyl]-phenyl}-2-1,2,3-triazol-2-yl-propionic acid (17j), was identified as a potent human PPARalpha/gamma dual agonist (EC(50)=0.013 and 0.061 microM, respectively) with demonstrated oral bioavailability in rat and dog. 17j was shown to decrease insulin levels, plasma glucose, and triglycerides in the ZDF female rat model. In the human apolipoprotein A-1/CETP transgenic mouse model 17j produced increases in hApoA1 and HDL-C and decreases in plasma triglycerides. The increased potency for binding and activation of both PPAR subtypes observed with 17j when compared to previous analogs in this series was explained based on results derived from crystallographic and modeling studies.

New target genes for the peroxisome proliferator-activated receptor-γ (PPARγ) antitumour activity: Perspectives from the insulin receptor

The insulin receptor (IR) plays a crucial role in mediating the metabolic and proliferative functions triggered by the peptide hormone insulin. There is considerable evidence that abnormalities in both IR expression and function may account for malignant transformation and tumour progression in some human neoplasias, including breast cancer. PPARγ is a ligand-activated, nuclear hormone receptor implicated in many pleiotropic biological functions related to cell survival and proliferation. In the last decade, PPARγ agonists—besides their known action and clinical use as insulin sensitizers—have proved to display a wide range of antineoplastic effects in cells and tissues expressing PPARγ, leading to intensive preclinical research in oncology. PPARγ and activators affect tumours by different mechanisms, involving cell proliferation and differentiation, apoptosis, antiinflammatory, and antiangiogenic effects. We recently provided evidence that PPARγ and agonists inhibit IR by non canonical, DNA-independent mechanisms affecting IR gene transcription. We conclude that IR may be considered a new PPARγ “target” gene, supporting a potential use of PPARγ agonists as antiproliferative agents in selected neoplastic tissues that overexpress the IR.

Cell based in vitro and ex vivo models in metabolic disease drug discovery: nice to have or critical path?

BACKGROUND

The use of cellular models as tools in drug discovery is almost universal. However, in disease areas such as metabolic diseases, are they relevant to the process and do they add value?

OBJECTIVE

In this article, we explore the variety of cellular models now used in drug discovery in metabolic diseases as revealed by publication. We have tried to make some connections between drug phenotypes in these models with clinical parallels. We also ask the question as to whether such models add value in the drug discovery process. This overview is not about recombinant cell systems used in target-based screening; rather, we focus on in vitro, including ex vivo, models as physiological systems in drug discovery in obesity and diabetes.

CONCLUSION

In terms of building target confidence, in vitro models are often the only mechanistic link to human systems early in a projects life. Many of the current targets in metabolic diseases in the early discovery phase are not yet clinically supported, let alone validated. In this respect, therefore, in vitro models warrant a place in the critical path in early discovery. In terms of any predictive role for decision-making today, this is much more difficult and is more likely pushed to a supporting role as part of a wider package. However, there is a rapid rate of advancement in this field and future developments hold much promise.

Lack of the serum and glucocorticoid-inducible kinase SGK1 attenuates the volume retention after treatment with the PPARgamma agonist pioglitazone

PPARgamma-agonists enhance insulin sensitivity and improve glucose utilization in diabetic patients. Adverse effects of PPARgamma-agonists include volume retention and edema formation. Recent observations pointed to the ability of PPARgamma agonists to enhance transcription of the serum and glucocorticoid-inducible kinase SGK1, a kinase that is genomically upregulated by mineralocorticoids and stimulates various renal channels and transporters including the renal epithelial Na+ channel ENaC. SGK1 has been proposed to mediate the volume retention after treatment with PPARgamma agonists. To test this hypothesis, food containing the PPARgamma agonist pioglitazone (0.02%, i.e., approximately 25 mg/kg bw/day) was administered to gene-targeted mice lacking SGK1 (sgk1-/-, n=12) and their wild-type littermates (sgk1+/+), n=12). According to in situ hybridization, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence, treatment with pioglitazone significantly increased renal SGK1 mRNA and protein expression in sgk1+/+ mice. The treatment increased body weight significantly in both, sgk1+/+ mice (+2.2+/-0.3 g) and sgk-/- mice (+1.3+/-0.2 g), and decreased hematocrit significantly in sgk1+/+ mice (-6.5+/-1.0%) and sgk1-/- mice (-3.1+/-0.6%). Both effects were significantly (p<0.05) more pronounced in sgk1+/+ mice. According to Evans Blue distribution, pioglitazone increased plasma volume only in sgk1+/+ mice (from 50.9+/-3.9 to 63.7+/-2.5 microl/g bw) but not in sgk-/- mice (from 46.8+/-3.8 to 48.3+/-5.2 microl/g bw). Pioglitazone decreased aldosterone plasma levels and blood pressure and increased leptin plasma levels in both genotypes. We conclude that SGK1 contributes to but does not fully account for the volume retention during treatment with the PPARgamma agonist pioglitazone.

Fat-specific protein 27, a novel lipid droplet protein that enhances triglyceride storage

Fat-specific protein (FSP)27/Cidec is most highly expressed in white and brown adipose tissues and increases in abundance by over 50-fold during adipogenesis. However, its function in adipocytes has remained elusive since its discovery over 15 years ago. Here we demonstrate that FSP27/Cidec localizes to lipid droplets in cultured adipocytes and functions to promote lipid accumulation. Ectopically expressed FSP27-GFP surrounds lipid droplets in 3T3-L1 adipocytes and colocalizes with the known lipid droplet protein perilipin. Immunostaining of endogenous FSP27 in 3T3-L1 adipocytes also confirmed its presence on lipid droplets. FSP27-GFP expression also markedly increases lipid droplet size and enhances accumulation of total neutral lipids in 3T3-L1 preadipocytes as well as other cell types such as COS cells. Conversely, RNA interference-based FSP27/Cidec depletion in mature adipocytes significantly stimulates lipolysis and reduces the size of lipid droplets. These data reveal FSP27/Cidec as a novel adipocyte lipid droplet protein that negatively regulates lipolysis and promotes triglyceride accumulation.

Association between cancer prevalence and use of thiazolidinediones: results from the Vermont Diabetes Information System

BACKGROUND

Peroxisome proliferator-activated receptors (PPARs) have emerged as important drug targets for diabetes. Drugs that activate PPARgamma, such as the thiazolidinediones (TZDs), are widely used for treatment of Type 2 diabetes mellitus. PPARgamma signaling could also play an anti-neoplastic role in several in vitro models, although conflicting results are reported from in vivo models. The effects of TZDs on cancer risk in humans needs to be resolved as these drugs are prescribed for long periods of time in patients with diabetes.

METHODS

A total of 1003 subjects in community practice settings were interviewed at home at the time of enrolment into the Vermont Diabetes Information System, a clinical decision support program. Patients self-reported their personal and clinical characteristics, including any history of malignancy. Laboratory data were obtained directly from the clinical laboratory and current medications were obtained by direct observation of medication containers. We performed a cross-sectional analysis of the interviewed subjects to assess a possible association between cancer diagnosis and the use of TZDs.

RESULTS

In a multivariate logistic regression model, a diagnosis of cancer was significantly associated with TZD use, even after correcting for potential confounders including other oral anti-diabetic agents (sulfonylureas and biguanides), age, glycosylated hemoglobin A1C, body mass index, cigarette smoking, high comorbidity, and number of prescription medications (odds ratio = 1.59, P = 0.04). This association was particularly strong among patients using rosiglitazone (OR = 1.89, P = 0.02), and among women (OR = 2.07, P = 0.01).

CONCLUSION

These data suggest an association between TZD use and cancer in patients with diabetes. Further studies are required to determine if this association is causal.

Evolution of Peroxisome Proliferator-Activated Receptor Agonists

OBJECTIVE:

To discuss the evolution of peroxisome proliferator-activated receptor (PPAR) agonists from single site to multiple subtype or partial agonists for the treatment of type 2 diabetes, dyslipidemia, obesity, and the metabolic syndrome.

DATA SOURCES:

Information was obtained from MEDLINE (1966-March 2007) using search terms peroxisome proliferator-activated receptor agonist, PPAR dual agonist, PPAR α/γ agonist, PPAR pan agonist, partial PPAR, and the specific compound names. Other sources included pharmaceutical companies, the Internet, and the American Diabetes Association 64th-66th Scientific Sessions abstract books.

STUDY SELECTION AND DATA EXTRACTION:

Animal data, abstracts, clinical trials, and review articles were reviewed and summarized.

DATA SYNTHESIS:

PPAR α, γ, and δ receptors play an important role in lipid metabolism, regulation of adipocyte proliferation and differentiation, and insulin sensitivity. The PPAR dual agonists were developed to combine the triglyceride lowering and high-density lipoprotein cholesterol elevation from the PPAR-α agonists (fibrates) with the insulin sensitivity improvement from the PPAR-γ agonists (thiazolidinediones). Although the dual agonists reduced hemoglobin A1C(A1C) and improved the lipid profile, adverse effects led to discontinued development. Currently, PPAR-γ agonists (GW501516 in Phase I trials), partial PPAR-γ agonists (metaglidasen in Phase II and III trials), and pan agonists (α, γ, δ netoglitazone in Phase II and III trials) with improved cell and tissue selectivity are undergoing investigation to address multiple aspects of the metabolic syndrome with a single medication. By decreasing both A1C and triglycerides, metaglidasen did improve multiple aspects of the metabolic syndrome with fewer adverse effects than compared with placebo. Metaglidasen is now being compared with pioglitazone.

CONCLUSIONS:

Influencing the various PPARs results in improved glucose, lipid, and weight management, with effects dependent on full or partial agonist activity at single or multiple receptors. Although the dual PPAR compounds have been associated with unacceptable toxicities, new PPAR agonist medications continue to be developed and investigated to discover a safe drug with benefits in multiple disease states.

Indanylacetic acids as PPAR-delta activator insulin sensitizers

A series of indane acetic acid derivatives were prepared which show a spectrum of activity as insulin sensitizers and PPAR-alpha and PPAR-delta ligands. In vivo data are presented for insulin sensitizers with selectivity for PPAR-delta over PPAR-alpha.

Design and synthesis of oxime ethers of α-acyl-β-phenylpropanoic acids as PPAR dual agonists

Oxime ethers of alpha-acyl-beta-phenylpropanoic acids were prepared to apply as PPARalpha and gamma dual agonists. Among them, compound 11l proved to exhibit potent in vitro activities with EC(50) of 19 and 13nM in PPARalpha and gamma, respectively. It showed better glucose lowering effects than rosiglitazone 1 and ameliorated the lipid profile like plasma triglyceride in db/db mice model.