Colette N. Miller

Phytochemicals as novel agents for the induction of browning in white adipose tissue

Obesity and its associated metabolic syndrome continue to be a health epidemic in westernized societies and is catching up in the developing world. Despite such increases, little headway has been made to reverse adverse weight gain in the global population. Few medical options exist for the treatment of obesity which points to the necessity for exploration of anti-obesity therapies including pharmaceutical and nutraceutical compounds. Defects in brown adipose tissue, a major energy dissipating organ, has been identified in the obese and is hypothesized to contribute to the overall metabolic deficit observed in obesity. Not surprisingly, considerable attention has been placed on the discovery of methods to activate brown adipose tissue. A variety of plant-derived, natural compounds have shown promise to regulate brown adipose tissue activity and enhance the lipolytic and catabolic potential of white adipose tissue. Through activation of the sympathetic nervous system, thyroid hormone signaling, and transcriptional regulation of metabolism, natural compounds such as capsaicin and resveratrol may provide a relatively safe and effective option to upregulate energy expenditure. Through utilizing the energy dissipating potential of such nutraceutical compounds, the possibility exists to provide a therapeutic solution to correct the energy imbalance that underlines obesity.

Isoproterenol Increases Uncoupling, Glycolysis, and Markers of Beiging in Mature 3T3-L1 Adipocytes.

Beta-adrenergic activation stimulates uncoupling protein 1 (UCP1), enhancing metabolic rate. In vitro, most work has studied brown adipocytes, however, few have investigated more established adipocyte lines such as the murine 3T3-L1 line. To assess the effect of beta-adrenergic activation, mature 3T3-L1s were treated for 6 or 48 hours with or without isoproterenol (10 and 100 μM) following standard differentiation supplemented with thyroid hormone (T3; 1 nM). The highest dose of isoproterenol increased lipid content following 48 hours of treatment. This concentration enhanced UCP1 mRNA and protein expression. The increase in UCP1 following 48 hours of isoproterenol increased oxygen consumption rate. Further, coupling efficiency of the electron transport chain was disturbed and an enhancement of glycolytic rate was measured alongside this, indicating an attempt to meet the energy demands of the cell. Lastly, markers of beige adipocytes (protein content of CD137 and gene transcript of CITED1) were also found to be upregulated at 48 hours of isoproterenol treatment. This data indicates that mature 3T3-L1 adipocytes are responsive to isoproterenol and induce UCP1 expression and activity. Further, this finding provides a model for further pharmaceutical and nutraceutical investigation of UCP1 in 3T3-L1s.

Estrogens, inflammation and obesity: an overview

Emerging research has suggested that inflammatory stress may play a role in the development of obesity. Both the leptin and insulin receptor are sensitive to intracellular inflammatory signaling that can be stimulated through toll-like receptor 4 activation by saturated fat. Pharmacological intervention within this cascade often protects animals from becoming obese, thus highlighting inflammatory pathways as a possible site of study in the prevention of pathologic weight gain. It has been well established in animal models that females display a marked reduction in the susceptibility to weight gain on high-fat diets compared to males. In addition, it has been widely accepted that females are partially protected from inflammatory-related diseases. At the molecular level, this reduction in disease susceptibility has been suggested to be due to the anti-inflammatory properties of 17 β-estradiol. Through direct free radical scavenging, transcriptional regulation, and protein interactions, chronic exposure to estradiol can reduce systemic inflammatory stress. As the knowledge base continues to grow on the etiology of obesity, further research is needed on the precise molecular pathways that can be inhibited by estradiol. Understanding of such pathways may provide a basis for the future use of estrogen and its related compounds (daidzein, genistein, resveratrol) to prevent weight gain in peri- and post-menopausal females.

A dietary phytochemical blend prevents liver damage associated with adipose tissue mobilization in ovariectomized rats

Menopausal reduction in estrogen causes increased adipose accumulation, leading many to turn to dietary supplements to prevent and treat such changes. Enhanced adipose mobilization stimulated by some supplements can increase the risk of non‐alcoholic fatty liver disease (NAFLD). Cytoprotective and anti‐obesity compounds may prevent the lipotoxicity associated with mobilization.

Acute exposure to high-fat diets increases hepatic expression of genes related to cell repair and remodeling in female rats

High-fat diets (HFD) promote the development of both obesity and fatty liver disease through the up-regulation of hepatic lipogenesis. Insulin resistance, a hallmark of both conditions, causes dysfunctional fuel partitioning and increases in lipogenesis. Recent work has demonstrated that systemic insulin resistance occurs in as little as the first 72 hours of an HFD, suggesting the potential for hepatic disruption with HFD at this time point. The current study sought to determine differences in expression of lipogenic genes between sexes in 3-month-old male and female Long-Evans rats after 72 hours of a 40% HFD or a 17% fat (chow) diet. Owing to the response of estrogen on hepatic signaling, we hypothesized that a sexual dimorphic response would occur in the expression of lipogenic enzymes, inflammatory cytokines, apoptotic, and cell repair and remodeling genes. Both sexes consumed more energy when fed an HFD compared with their low fat-fed controls. However, only the males fed the HFD had a significant increase in body fat. Regardless of sex, HFD caused down-regulation of lipogenic and inflammatory genes. Interestingly, females fed an HFD had up-regulated expression of apoptotic and cell repair-related genes compared with the males. This may suggest that females are more responsive to the acute hepatic injury effects caused by HFDs. In summary, neither male nor female rats displayed disrupted hepatic metabolic pathways after 72 hours of the HFD treatment. In addition, female rats appear to have protection from increases in fat deposition, possibly due to increased caloric expenditure; male rats fed an HFD were less active, as demonstrated by distance traveled in their home cage.

Adrenergic and glucocorticoid receptor antagonists reduce ozone-induced lung injury and inflammation

&NA; Recent studies showed that the circulating stress hormones, epinephrine and corticosterone/cortisol, are involved in mediating ozone‐induced pulmonary effects through the activation of the sympathetic‐adrenal‐medullary (SAM) and hypothalamus‐pituitary‐adrenal (HPA) axes. Hence, we examined the role of adrenergic and glucocorticoid receptor inhibition in ozone‐induced pulmonary injury and inflammation. Male 12‐week old Wistar‐Kyoto rats were pretreated daily for 7 days with propranolol (PROP; a non‐selective &bgr; adrenergic receptor [AR] antagonist, 10 mg/kg, i.p.), mifepristone (MIFE; a glucocorticoid receptor [GR] antagonist, 30 mg/kg, s.c.), both drugs (PROP + MIFE), or respective vehicles, and then exposed to air or ozone (0.8 ppm), 4 h/d for 1 or 2 consecutive days while continuing drug treatment. Ozone exposure alone led to increased peak expiratory flow rates and enhanced pause (Penh); with greater increases by day 2. Receptors blockade minimally affected ventilation in either air‐ or ozone‐exposed rats. Ozone exposure alone was also associated with marked increases in pulmonary vascular leakage, macrophage activation, neutrophilic inflammation and lymphopenia. Notably, PROP, MIFE and PROP + MIFE pretreatments significantly reduced ozone‐induced pulmonary vascular leakage; whereas PROP or PROP + MIFE reduced neutrophilic inflammation. PROP also reduced ozone‐induced increases in bronchoalveolar lavage fluid (BALF) IL‐6 and TNF‐&agr; proteins and/or lung Il6 and Tnf&agr; mRNA. MIFE and PROP + MIFE pretreatments reduced ozone‐induced increases in BALF N‐acetyl glucosaminidase activity, and lymphopenia. We conclude that stress hormones released after ozone exposure modulate pulmonary injury and inflammatory effects through AR and GR in a receptor‐specific manner. Individuals with pulmonary diseases receiving AR and GR‐related therapy might experience changed sensitivity to air pollution. HighlightsBlocking beta adrenergic and/or glucocorticoid receptors inhibit ozone‐induced lung protein leakage.Blocking beta adrenergic but not glucocorticoid receptors inhibit ozone‐induced lung neutrophilia.Blocking beta adrenergic receptors inhibit ozone‐induced lung cytokine expression.Blocking glucocorticoid but not beta adrenergic receptors inhibit ozone‐induced lung lymphopenia.Pulmonary ozone effects are modulated by beta adrenergic and glucocorticoid receptors.

The Mediation of Hepatic Lipogenesis Through Estrogens

Estrogens have been shown to protect against various diseases and disastrous metabolic consequences of poor diets. Although a large body of research demonstrates estrogens ability to control food intake, adipogenesis, and oxidative stress, research regarding the effects of estrogens on hepatic lipogenesis, steatosis, and non-alcoholic fatty liver disease is only now accumulating. Estrogen deficiency in both human and rodent models directly results in the upregulation of hepatic lipogenic signaling - in both serum and hepatic triglyceride content - which leads to the development of fatty liver. In all models, estrogen replacement completely reverses these outcomes. Similar to the endogenous estrogen hormone, plant-derived phytoestrogens also appear to have beneficial effects related to prevention of hepatic lipogenic signaling and steatosis in rodent models. Additionally, such compounds can completely overcome the hepatic consequences that result from estrogen deficiency. While published research strongly supports that estrogens, both endogenous and exogenous, can protect against hepatic lipogenic signaling that can contribute to the development of non-alcoholic fatty liver diseases and adverse weight gain, little research exists on elucidating the mechanism behind this protection. Various pathways have been suggested, including manipulation of both leptin and signal transducer and activator of transcription 3 (STAT3) signaling. However, the discovery of x-box protein 1 elicits the identification of another potential pathway through which estrogen may be working. While the supportive work is strong, further research is needed to determine the mechanism behind the protection by estrogens from hepatic lipogenesis and associated diseases.

Acute inhalation of ozone induces DNA methylation of apelin in lungs of Long-Evans rats

Abstract Apelin has cardiopulmonary protective properties that promote vasodilation and maintenance of the endothelial barrier. While reductions in apelin have been identified as a contributor to various lung diseases, including pulmonary edema, its role in the effect of air pollutants has not been examined. Thus, in the current study, we sought to investigate if apelin is a downstream target of inhaled ozone and if such change in expression is related to altered DNA methylation in the lung. Male, Long-Evans rats were exposed to filtered air or 1.0 ppm ozone for 4 h. Ventilation changes were assessed using whole-body plethysmography immediately following exposure, and markers of pulmonary edema and inflammation were assessed in the bronchoaveolar lavage (BAL) fluid. The enzymatic regulators of DNA methylation were measured in the lung, along with methylation and hydroxymethylation of the apelin promoter. Data showed that ozone exposure was associated with increased enhanced pause and protein leakage in the BAL fluid. Ozone exposure reduced DNA cytosine-5-methyltransferase (DNMT) activity and Dnmt3a/b gene expression. Exposure-induced upregulation of proliferating cell nuclear antigen, indicative of DNA damage, repair, and maintenance methylation. Increased methylation and reduced hydroxymethylation were measured on the apelin promoter. These epigenetic modifications accompanied ozone-induced reduction of apelin expression and development of pulmonary edema. In conclusion, epigenetic regulation, specifically increased methylation of the apelin promoter downstream of DNA damage, may lead to reductions in protective signaling of the apelinergic system, contributing to the pulmonary edema observed following the exposure to oxidant air pollution.

UCP1 in sebaceous glands corresponds with increased antioxidant potential and not brown adipose tissue function

needed stem cell transplantation. Consequently, our data cannot provide sufficient proof of CSC presence in CL according to the markers used, but it cannot be ruled out as well. In particular, the fact that part of the CTCL biopsies were taken after therapy potentially masks possible CSC presence prior to therapy. Still, our data suggest CSC presence in LC and systemic lymphoma. Therefore, these markers might become a valuable tool to distinguish CL and skin infiltrates of primary systemic lymphoma or leukaemia both in blood and skin. To identify CSC in CL, a promising future research avenue includes genomic and transcriptomic analyses because aberrations here can induce stem cell properties to lymphocytes (S3). In addition, functional studies could be valuable in proving the selfrenewing character of CSC in CL and to develop and test specific CSC-directed therapies. Acknowledgements J.P.N. and C.D.K. designed the study. J.P.N., T.G. and S.S. performed experiments. J.P. N., T.G., S.S. and M.F. analysed the data. J.P.N. and C.D.K. wrote the manuscript. The authors like to thank Anneliese Pfisterer, Sayran Arif-Said, Inge R€ ohmer and Karin Hartmann for excellent technical support in performing immunohistochemistry and FACS analysis as well as Dieter Krahl for providing leukaemia cutis samples. Conflict of interests J.P.N. received travel and congress participation funding by TEVA company as well as consulting fees by TEVA and Biogen Idec companies. M.F. received travel and congress participation funding by TEVA company. C.D.K. received travel support for scientific conferences and lecture fees for scientific presentations from TEVA/Cephalon Pharma GmbH and Therakos, Johnson & Johnson Medical GmbH. He is a member of the TEVA Cutaneous Lymphoma Advisory Board. Supporting Information