Author
David E. Moller
Other affiliations: Dana Corporation, Eli Lilly and Company, Mount Sinai St. Luke's and Mount Sinai Roosevelt ...read more
Bio: David E. Moller is an academic researcher from Merck & Co.. The author has contributed to research in topics: Insulin & Insulin receptor. The author has an hindex of 77, co-authored 157 publications receiving 28007 citations. Previous affiliations of David E. Moller include Dana Corporation & Eli Lilly and Company.
Papers published on a yearly basis
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TL;DR: It is reported that metformin activates AMPK in hepatocytes; as a result, acetyl-CoA carboxylase (ACC) activity is reduced, fatty acid oxidation is induced, and expression of lipogenic enzymes is suppressed.
Abstract: Metformin is a widely used drug for treatment of type 2 diabetes with no defined cellular mechanism of action. Its glucose-lowering effect results from decreased hepatic glucose production and increased glucose utilization. Metformin's beneficial effects on circulating lipids have been linked to reduced fatty liver. AMP-activated protein kinase (AMPK) is a major cellular regulator of lipid and glucose metabolism. Here we report that metformin activates AMPK in hepatocytes; as a result, acetyl-CoA carboxylase (ACC) activity is reduced, fatty acid oxidation is induced, and expression of lipogenic enzymes is suppressed. Activation of AMPK by metformin or an adenosine analogue suppresses expression of SREBP-1, a key lipogenic transcription factor. In metformin-treated rats, hepatic expression of SREBP-1 (and other lipogenic) mRNAs and protein is reduced; activity of the AMPK target, ACC, is also reduced. Using a novel AMPK inhibitor, we find that AMPK activation is required for metformin's inhibitory effect on glucose production by hepatocytes. In isolated rat skeletal muscles, metformin stimulates glucose uptake coincident with AMPK activation. Activation of AMPK provides a unified explanation for the pleiotropic beneficial effects of this drug; these results also suggest that alternative means of modulating AMPK should be useful for the treatment of metabolic disorders.
5,146 citations
TL;DR: The current state of knowledge regarding the molecular mechanisms of PPAR action and the involvement of the PPARs in the etiology and treatment of several chronic diseases is presented.
Abstract: ▪ Abstract The peroxisome proliferator-activated receptors (PPARs) are a group of three nuclear receptor isoforms, PPARγ, PPARα, and PPARδ, encoded by different genes. PPARs are ligand-regulated transcription factors that control gene expression by binding to specific response elements (PPREs) within promoters. PPARs bind as heterodimers with a retinoid X receptor and, upon binding agonist, interact with cofactors such that the rate of transcription initiation is increased. The PPARs play a critical physiological role as lipid sensors and regulators of lipid metabolism. Fatty acids and eicosanoids have been identified as natural ligands for the PPARs. More potent synthetic PPAR ligands, including the fibrates and thiazolidinediones, have proven effective in the treatment of dyslipidemia and diabetes. Use of such ligands has allowed researchers to unveil many potential roles for the PPARs in pathological states including atherosclerosis, inflammation, cancer, infertility, and demyelination. Here, we presen...
2,421 citations
TL;DR: Emerging knowledge of key pathogenic mechanisms, such as the impairment of glucose-stimulated insulin secretion and the role of 'lipotoxicity' as a probable cause of hepatic and muscle resistance to insulin's effects on glucose metabolism, has led to a host of new molecular drug targets.
Abstract: An insidious increase in features of the 'metabolic syndrome' - obesity, insulin resistance and dyslipidaemia -- has conspired to produce a worldwide epidemic of type 2 insulin-resistant diabetes mellitus. Most current therapies for this disease were developed in the absence of defined molecular targets or an understanding of disease pathogenesis. Emerging knowledge of key pathogenic mechanisms, such as the impairment of glucose-stimulated insulin secretion and the role of 'lipotoxicity' as a probable cause of hepatic and muscle resistance to insulin's effects on glucose metabolism, has led to a host of new molecular drug targets. Several have been validated through genetic engineering in mice or the preliminary use of lead compounds and therapeutic agents in animals and humans.
1,008 citations
TL;DR: It is reported that systemic administration of FGF21 for 2 wk in diet-induced obese and ob/ob mice lowered their mean body weight by 20% predominantly via a reduction in adiposity.
Abstract: Fibroblast growth factor 21 (FGF21) is a metabolic regulator that provides efficient and durable glycemic and lipid control in various animal models. However, its potential to treat obesity, a major health concern affecting over 30% of the population, has not been fully explored. Here we report that systemic administration of FGF21 for 2 wk in diet-induced obese and ob/ob mice lowered their mean body weight by 20% predominantlyviaareductioninadiposity.Althoughnodecrease in total caloric intake or effect on physical activity was observed,FGF21-treatedanimalsexhibitedincreasedenergyexpenditure, fat utilization, and lipid excretion, reduced hepatosteatosis, and ameliorated glycemia. Transcriptional and blood cytokine profiling studies revealed effects consistent with the ability of FGF21 to ameliorate insulin and leptin resistance, enhance fat oxidation and suppress de novo lipogenesis in liver aswellastoactivatefutilecyclinginadipose.Overall,thesedata suggestthatFGF21exhibitsthetherapeuticcharacteristicsnecessary for an effective treatment of obesity and fatty liver disease and provides novel insights into the metabolic determinants of these activities. (Endocrinology 149: 6018–6027, 2008)
919 citations
TL;DR: The findings suggest that the metabolic effects of metformin in subjects with type 2 diabetes may be mediated by the activation of AMPK alpha2, which is implicated in the stimulation of glucose uptake into skeletal muscle and the inhibition of liver gluconeogenesis.
Abstract: Metformin is an effective hypoglycemic drug that lowers blood glucose concentrations by decreasing hepatic glucose production and increasing glucose disposal in skeletal muscle; however, the molecular site of metformin action is not well understood. AMP-activated protein kinase (AMPK) activity increases in response to depletion of cellular energy stores, and this enzyme has been implicated in the stimulation of glucose uptake into skeletal muscle and the inhibition of liver gluconeogenesis. We recently reported that AMPK is activated by metformin in cultured rat hepatocytes, mediating the inhibitory effects of the drug on hepatic glucose production. In the present study, we evaluated whether therapeutic doses of metformin increase AMPK activity in vivo in subjects with type 2 diabetes. Metformin treatment for 10 weeks significantly increased AMPK alpha2 activity in the skeletal muscle, and this was associated with increased phosphorylation of AMPK on Thr172 and decreased acetyl-CoA carboxylase-2 activity. The increase in AMPK alpha2 activity was likely due to a change in muscle energy status because ATP and phosphocreatine concentrations were lower after metformin treatment. Metformin-induced increases in AMPK activity were associated with higher rates of glucose disposal and muscle glycogen concentrations. These findings suggest that the metabolic effects of metformin in subjects with type 2 diabetes may be mediated by the activation of AMPK alpha2.
803 citations
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TL;DR: This integrating paradigm provides a new conceptual framework for future research and drug discovery in diabetes-specific microvascular disease and seems to reflect a single hyperglycaemia-induced process of overproduction of superoxide by the mitochondrial electron-transport chain.
Abstract: Diabetes-specific microvascular disease is a leading cause of blindness, renal failure and nerve damage, and diabetes-accelerated atherosclerosis leads to increased risk of myocardial infarction, stroke and limb amputation. Four main molecular mechanisms have been implicated in glucose-mediated vascular damage. All seem to reflect a single hyperglycaemia-induced process of overproduction of superoxide by the mitochondrial electron-transport chain. This integrating paradigm provides a new conceptual framework for future research and drug discovery.
8,289 citations
TL;DR: Since the 1990 NIH-sponsored conference on polycystic ovary syndrome, it has become appreciated that the syndrome encompasses a broader spectrum of signs and symptoms of ovarian dysfunction than those defined by the original diagnostic criteria.
8,217 citations
TL;DR: Dysfunction of the immune response and metabolic regulation interface can be viewed as a central homeostatic mechanism, dysfunction of which can lead to a cluster of chronic metabolic disorders, particularly obesity, type 2 diabetes and cardiovascular disease.
Abstract: Metabolic and immune systems are among the most fundamental requirements for survival. Many metabolic and immune response pathways or nutrient- and pathogen-sensing systems have been evolutionarily conserved throughout species. As a result, immune response and metabolic regulation are highly integrated and the proper function of each is dependent on the other. This interface can be viewed as a central homeostatic mechanism, dysfunction of which can lead to a cluster of chronic metabolic disorders, particularly obesity, type 2 diabetes and cardiovascular disease. Collectively, these diseases constitute the greatest current threat to global human health and welfare.
7,536 citations
TL;DR: A role for TNF-alpha in obesity and particularly in the insulin resistance and diabetes that often accompany obesity is indicated.
Abstract: Tumor necrosis factor-alpha (TNF-alpha) has been shown to have certain catabolic effects on fat cells and whole animals. An induction of TNF-alpha messenger RNA expression was observed in adipose tissue from four different rodent models of obesity and diabetes. TNF-alpha protein was also elevated locally and systemically. Neutralization of TNF-alpha in obese fa/fa rats caused a significant increase in the peripheral uptake of glucose in response to insulin. These results indicate a role for TNF-alpha in obesity and particularly in the insulin resistance and diabetes that often accompany obesity.
7,347 citations
TL;DR: It is proposed that obesity-related insulin resistance is, at least in part, a chronic inflammatory disease initiated in adipose tissue, and that macrophage-related inflammatory activities may contribute to the pathogenesis of obesity-induced insulin resistance.
Abstract: Insulin resistance arises from the inability of insulin to act normally in regulating nutrient metabolism in peripheral tissues Increasing evidence from human population studies and animal research has established correlative as well as causative links between chronic inflammation and insulin resistance However, the underlying molecular pathways are largely unknown In this report, we show that many inflammation and macrophage-specific genes are dramatically upregulated in white adipose tissue (WAT) in mouse models of genetic and high-fat diet-induced obesity (DIO) The upregulation is progressively increased in WAT of mice with DIO and precedes a dramatic increase in circulating-insulin level Upon treatment with rosiglitazone, an insulin-sensitizing drug, these macrophage-originated genes are downregulated Histologically, there is evidence of significant infiltration of macrophages, but not neutrophils and lymphocytes, into WAT of obese mice, with signs of adipocyte lipolysis and formation of multinucleate giant cells These data suggest that macrophages in WAT play an active role in morbid obesity and that macrophage-related inflammatory activities may contribute to the pathogenesis of obesity-induced insulin resistance We propose that obesity-related insulin resistance is, at least in part, a chronic inflammatory disease initiated in adipose tissue
6,165 citations