Sanford Burnham Prebys Medical Discovery Institute at Lake Nona

Orlando, FL, United States

Sanford Burnham Prebys Medical Discovery Institute at Lake Nona

Orlando, FL, United States
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Brown J.D.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Karimian Azari E.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Ayala J.E.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona
Physiology and Behavior | Year: 2017

Obesity is a pandemic, gateway disease that has thrived in modern, sedentary, high calorie-eating societies. Left unchecked, obesity and obesity-related diseases will continue to plague future generations with heavy burdens on economies, healthcare systems, and the quality of life of billions. There is a significant need to elucidate basic physiological mechanisms and therapies that address this global health care crisis. Oleoylethanolamide (OEA) is an endocannabinoid-like lipid that induces hypophagia and reduces fat mass in rodents. For over a decade, PPAR-α has been the most widely accepted mediator of the hypophagic action of OEA via signaling to homeostatic brain centers. Recent evidence suggests that OEA may also reduce food intake via effects on dopamine and endocannabinoid signaling within hedonic brain centers. Limited study of OEA supplementation in humans has provided some encouraging insight into OEA-based weight loss therapy, but more thorough, controlled investigations are needed. As a potential link between homeostatic and hedonic regulation of food intake, OEA is a prime starting point for the development of more effective obesity therapies. © 2017.

Collins S.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Van Hook A.M.,Science Signaling
Science Signaling | Year: 2017

This Podcast features a conversation with Shelia Collins, senior author of a Research Article that appears in the 25 July 2017 issue of Science Signaling, about how cardiac natriuretic peptides (NPs) exert their beneficial effects on whole-body metabolism. NPs control blood pressure by acting on the kidneys, but they also affect metabolism by stimulating adipose tissue and skeletal muscle to become more metabolically active. Obese individuals have less of these peptides circulating in their blood, suggesting a connection between NP signaling and obesity. NPs stimulate intracellular signaling by binding to and activating the receptors NPRA and NPRB. A third receptor, the NP clearance receptor (NPRC), antagonizes signaling through NPRA and NPRB by binding to and stimulating the internalization and degradation of NPs. To determine whether the beneficial metabolic effects of NPs were due to the action of these peptides in adipose tissue or in skeletal muscle, Wu et al. knocked out NPRC specifically in these tissues in mice. Although mice lacking NPRC in skeletal muscle responded similarly to a high-fat diet as wild-type mice, mice lacking NPRC in adipose tissue were resistant to many of the detrimental metabolic effects of a high-fat diet. These findings suggest that stimulating NP signaling or inhibiting NPRC in adipose tissue may be a potential strategy for treating metabolic disease.

Vega R.B.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Konhilas J.P.,University of Arizona | Kelly D.P.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Leinwand L.A.,University of Colorado at Boulder
Cell Metabolism | Year: 2017

Exercise elicits coordinated multi-organ responses including skeletal muscle, vasculature, heart, and lung. In the short term, the output of the heart increases to meet the demand of strenuous exercise. Long-term exercise instigates remodeling of the heart including growth and adaptive molecular and cellular re-programming. Signaling pathways such as the insulin-like growth factor 1/PI3K/Akt pathway mediate many of these responses. Exercise-induced, or physiologic, cardiac growth contrasts with growth elicited by pathological stimuli such as hypertension. Comparing the molecular and cellular underpinnings of physiologic and pathologic cardiac growth has unveiled phenotype-specific signaling pathways and transcriptional regulatory programs. Studies suggest that exercise pathways likely antagonize pathological pathways, and exercise training is often recommended for patients with chronic stable heart failure or following myocardial infarction. Herein, we summarize the current understanding of the structural and functional cardiac responses to exercise as well as signaling pathways and downstream effector molecules responsible for these adaptations. © 2017

Maurya S.K.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Periasamy M.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona
Pharmacological Research | Year: 2015

Obesity is increasing at an alarming rate, both in adults and adolescents, across the globe due to increased consumption of caloric rich diet. Obesity and its associated complications appear to be major contributing factors not only to diabetes/heart disease but also to cancer, and neurological diseases causing a huge burden on the health care system. To date, there are no effective treatments to reduce weight gain, other than caloric restriction and exercise which are often difficult to enforce. There are very few drugs available for treating obesity and those that are available only reduce obesity by ∼10%. Identifying mechanisms to increase energy expenditure, on top of the increase elicited by exercise, would be more beneficial to control weight gain. The purpose of this review is to highlight the role of sarcolipin (SLN), a regulator of SERCA pump, in muscle thermogenesis and metabolism. We will further discuss if enhancing SLN activity could be an effective mechanism to increase energy expenditure and control weight gain. We will also discuss the merits of adaptive thermogenesis in muscle and brown fat as potential mechanisms to increase energy expenditure during caloric overload. That said, there is still a great need for further research into the mechanism of diet induced thermogenesis and its relevance to overall metabolism and obesity. © 2015 Elsevier Ltd.

PubMed | Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, University of Florida and The Interdisciplinary Center
Type: | Journal: Molecular plant pathology | Year: 2016

DEFORMED ROOT AND LEAVES1 (DRL1) is an Arabidopsis homologue of the yeast TOXIN TARGET4 (TOT4)/KILLER TOXIN-INSENSITIVE12 (KTI12) protein that is physically associated with the RNA polymerase II interacting protein complex named Elongator. Mutations in DRL1 and Elongator lead to similar morphological and molecular phenotypes, suggesting that DRL1 and Elongator may functionally overlap in Arabidopsis. We have previously shown that Elongator plays an important role in both salicylic acid (SA)- and jasmonic acid (JA)/ethylene (ET)-mediated defense responses. Here, we tested whether DRL1 also plays a similar role as Elongator in plant immune responses. Our results show that, although DRL1 partially contributes to SA-caused cytotoxicity, it does not play a significant role in SA-mediated expression of PATHOGENESIS-RELATED genes and resistance to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola ES4326. In constrast, DRL1 is required for JA/ET- and the necrotrophic fungal pathogen Botrytis cinerea-induced defense gene expression and for resistance to B. cinerea and Alternaria brassicicola. Furthermore, unlike the TOT4/KTI12 gene, which when overexpressed in yeast confers zymocin resistance, a phenotype of the tot4/kti12 mutant, overexpression of DRL1 does not change B. cinerea-induced defense gene expression and resistance to this pathogen. Finally, DRL1 contains an N-terminal P-loop and a C-terminal calmodulin (CaM)-binding domain and is a CaM-binding protein. We demonstrate that both the P-loop and the CaM-binding domain are essential for DRL1s function in B. cinerea-induced expression of PDF1.2 and ORA59 and in resistance to B. cinerea, suggestting that DRL1s function in plant immunity may be regulated by ATP/GTP and CaM binding. This article is protected by copyright. All rights reserved.

PubMed | Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, University of Tampere, University of Jyväskylä and Kuopio University Hospital
Type: Journal Article | Journal: Investigative ophthalmology & visual science | Year: 2016

The role of R-Ras in retinal angiogenesis and vascular permeability was evaluated in an oxygen-induced retinopathy (OIR) model using R-Ras knockout (KO) mice and in human diabetic neovascular membranes.Mice deficient for R-Ras and their wild-type (WT) littermates were subjected to 75% oxygen from postnatal day 7 (P7) to P12 and then returned to room air. At P17 retinal vascularization was examined from whole mounts, and retinal vascular permeability was studied using Miles assay. Real-time RT-PCR, Western blotting, and immunohistochemistry were used to assess the expression of R-Ras in retina during development or in the OIR model. The degree of pericyte coverage and vascular endothelial (VE)-cadherin expression on WT and R-Ras KO retinal blood vessels was quantified using confocal microscopy. The correlation of R-Ras with vascular endothelial growth factor receptor 2 (VEGFR2) and human serum albumin on human proliferative diabetic retinopathy membranes was assessed using immunohistochemistry.In retina, R-Ras expression was mostly restricted to the vasculature. Retinal vessels in the R-Ras KO mice were significantly more permeable than WT controls in the OIR model. A significant reduction in the direct physical contact between pericytes and blood vessel endothelium as well as reduced VE-cadherin immunostaining was found in R-Ras-deficient mice. In human proliferative diabetic retinopathy neovascular membranes, R-Ras expression negatively correlated with increased vascular leakage and expression of VEGFR2, a marker of blood vessel immaturity.Our results suggest that R-Ras has a role in controlling retinal vessel maturation and stabilization in ischemic retinopathy and provides a potential target for pharmacologic manipulation to treat diabetic retinopathy.

PubMed | Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, University of Toronto and Mt Sinai Hospital
Type: Journal Article | Journal: Cell metabolism | Year: 2016

Pharmacological inhibition of the dipeptidyl peptidase-4 (DPP4) enzyme potentiates incretin action and is widely used to treat type 2 diabetes. Nevertheless, the precise cells and tissues critical for incretin degradation and glucose homeostasis remain unknown. Here, we use mouse genetics and pharmacologic DPP4 inhibition to identify DPP4

Sandor K.,Debrecen University | Daniel B.,Debrecen University | Daniel B.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Kiss B.,Debrecen University | And 2 more authors.
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms | Year: 2016

Transglutaminase 2 (TGM2) is a ubiquitously expressed multifunctional protein, which participates in various biological processes including thymocyte apoptosis. As a result, the transcriptional regulation of the gene is complex and must depend on the cell type. Previous studies from our laboratory have shown that in dying thymocytes the expression of Tgm2 is induced by external signals derived from engulfing macrophages, such as retinoids, transforming growth factor (TGF)-β and adenosine, the latter triggering the adenylate cyclase signaling pathway. The existence of TGF-β and retinoid responsive elements in the promoter region of Tgm2 has already been reported, but the intergenic regulatory elements participating in the regulation of Tgm2 have not yet been identified. Here we used publicly available results from DNase I hypersensitivity analysis followed by deep sequencing and chromatin immunoprecipitation followed by deep sequencing against CCCTC-binding factor (CTCF), H3K4me3, H3K4me1 and H3K27ac to map a putative regulatory element set for Tgm2 in thymocytes. By measuring eRNA expressions of these putative enhancers in retinoid, rTGF-β or dibutiryl cAMP-exposed thymocytes we determined which of them are functional. By applying ChIP-qPCR against SMAD4, retinoic acid receptor, retinoid X receptor, cAMP response element binding protein, P300 and H3K27ac under the same conditions, we identified two enhancers of Tgm2, which seem to act as integrators of the TGF-β, retinoid and adenylate cyclase signaling pathways in dying thymocytes. Our study describes a novel strategy to identify and characterize the signal-specific functional enhancer set of a gene by integrating genome-wide datasets and measuring the production of enhancer specific RNA molecules. © 2016 Elsevier B.V..

PubMed | Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Sanford Burnham Institute for Medical Research and Debrecen University
Type: | Journal: Journal of visualized experiments : JoVE | Year: 2016

Embryonic development is a multistep process involving activation and repression of many genes. Enhancer elements in the genome are known to contribute to tissue and cell-type specific regulation of gene expression during the cellular differentiation. Thus, their identification and further investigation is important in order to understand how cell fate is determined. Integration of gene expression data (e.g., microarray or RNA-seq) and results of chromatin immunoprecipitation (ChIP)-based genome-wide studies (ChIP-seq) allows large-scale identification of these regulatory regions. However, functional validation of cell-type specific enhancers requires further in vitro and in vivo experimental procedures. Here we describe how active enhancers can be identified and validated experimentally. This protocol provides a step-by-step workflow that includes: 1) identification of regulatory regions by ChIP-seq data analysis, 2) cloning and experimental validation of putative regulatory potential of the identified genomic sequences in a reporter assay, and 3) determination of enhancer activity in vivo by measuring enhancer RNA transcript level. The presented protocol is detailed enough to help anyone to set up this workflow in the lab. Importantly, the protocol can be easily adapted to and used in any cellular model system.

Sawada J.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Li F.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona | Komatsu M.,Sanford Burnham Prebys Medical Discovery Institute at Lake Nona
Journal of Vascular Research | Year: 2016

R-Ras is a Ras family small GTPase that is highly expressed in mature functional blood vessels in normal tissues. It inhibits pathological angiogenesis and promotes vessel maturation and stabilization. Previous studies suggest that R-Ras affects cellular signaling in endothelial cells, pericytes and smooth-muscle cells to regulate vessel formation and remodeling in adult tissues. R-Ras suppresses VEGF-induced endothelial permeability and vessel sprouting while promoting normalization of pathologically developing vessels in mice. It attenuates VEGF receptor-2 (VEGFR2) activation by inhibiting internalization of the receptor upon VEGF ligand binding, leading to significant reduction of VEGFR2 autophosphorylation. Here, we show that R-Ras strongly suppresses the VEGF-dependent activation of stress-activated protein kinase-2/p38 mitogen-activated protein kinase (SAPK2/p38MAPK) and the phosphorylation of downstream heat-shock protein 27 (HSP27), a regulator of actin cytoskeleton organization, in endothelial cells. The suppression of p38MAPK activation and HSP27 phosphorylation by R-Ras concurred with altered actin cytoskeleton architecture, reduced membrane protrusion and inhibition of endothelial cell migration toward VEGF. Silencing of endogenous R-Ras by RNA interference increased membrane protrusion and cell migration stimulated by VEGF, and these effects were offset by p38MAPK inhibitor SB203580. These results suggest that R-Ras regulates angiogenic activities of endothelial cells in part via inhibition of the p38MAPK-HSP27 axis of VEGF signaling. © 2016 The Author(s) Published by S. Karger AG, Basel.

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