Post on 25-Dec-2014
description
Presented by: Cheryl Gregory
Linh Pho
Kari E. Wong, Frances L. Szeto, Wenshuo Zhang, Honggang Ye, Juan Kong, Zhongyi Zhang, Xiao Jian Sun, and Yan Chun Li
22 January 2009
� Introduction
� Materials & Methods
� Results� Results◦ Graphs & Diagrams
� Conclusion
� Further Research
� What is the definition of obesity?◦ The Excess of Body Fat
� What is the prevalence of obesity in the United States?◦ In 2008, the obesity prevalence increased to 30%
� What are the associated health � What are the associated health problems?◦ Gangreen◦ Type II Diabetes ◦ Cancer◦ Cardiovascular Disease◦ Hypertension
http://science.kukuchew.com/wp-content/uploads/2009/02/obesity_surgery.jpg
ØEnergy Metabolism: the use of fuels to create energy to be used for work.
ØVitamin DVitamin DVitamin DVitamin D----Receptor (VDR) knockout mice used to show Receptor (VDR) knockout mice used to show Receptor (VDR) knockout mice used to show Receptor (VDR) knockout mice used to show Vitamin D, 1alpha,25Vitamin D, 1alpha,25Vitamin D, 1alpha,25Vitamin D, 1alpha,25----dihydroxyvitamin Ddihydroxyvitamin Ddihydroxyvitamin Ddihydroxyvitamin D----3, involvement in 3, involvement in 3, involvement in 3, involvement in energy metabolism energy metabolism energy metabolism energy metabolism
ØVDR-null mice had decreased adiposity and lower plasma lipid levels
ØVDR-null mice had increased Uncoupling Protein expressionØUCPs separate the process of oxidative phosphorylation from ATP production
ØOverall, VDR knockout mice had higher energy expenditure
� Animal Treatment◦ Created Vitamin D Receptor (VDR) knockout mice◦ Placed the mice on two diets: High Fat & High Calcium� High Fat (HF)
� Mice were place on HCa for 4 months, then switch to HF dietMice were weighed and monitored weekly� Mice were weighed and monitored weekly
� End, animals were killed: plasma and adipose tissue were harvested
� High Calcium (HCa)� To normalize the plasma calcium level� Used as a control
� Assessed Plasma Parameters Using Test Kits◦ Used to determine levels of:� Triglycerides� Cholesterol� Adipokine� Adipokine� Thyroid Stimulating Hormone
� Observed the Histology ◦ Cultured White Adipose Tissue (WAT)� Storage depot of the body� Stores excess energy in triglyceride form� Releases signals indicating the body’s energy state
◦ Cultured Brown Adipose Tissue (BAT)� Regulates thermogenesis� Expresses uncoupling protein
� Separate oxidative phosphorylation from ATP production
◦ Adipose tissues were:� Processed and Stained
� Assayed Fatty Acid B-oxidation◦ Isolated white adipose tissue from male mice ◦ Measure the B-oxidation using tritiated palmitate
� Analyzed Northern Blot of total RNA� Analyzed Northern Blot of total RNA◦ Show the total cellular RNA extraction
� Performed RT-PCR◦ Strands of DNA extracted from the mice◦ To analyze protein and hormone mRNA levels
Weight DifferenceWeight DifferenceWeight DifferenceWeight Difference
•VDR (-/-) mice weighed sig. less than WT on both high-Ca++ and high-fat diet
•Gender difference: Male mice more protected against weight gain
MALE FEMALE
•VDR-null mice had a decrease in adiposity•Lower # of adipocytes•Smaller size
ADIPOSE DIFFERENCE
•VDR-null mice on the high-fat diet had smaller adipocytes & less BAT
•The BAT accumulated fewer lipids & had better cell morphology
C. White Adipose Tissue
& had better cell morphology
•VDR-null had less adipose tiss. in all fat depots
•More dramatic difference between males
D. Brown Adipose Tissue
MALE MICE ONLY
Fatty acid synthase higher in VDR-null mice on HCa diet but diff. not as big on HF diet
ENZYME LEVELS
diff. not as big on HF diet
Malonyl-CoA Dehydrogenase and Stearoyl CoA-Desaturase-1 were not significantly different
LPL lower in mutant mice on HF diet
PPAR-gamma higher in mutant mice on HCa diet
Fatty Acid Synthase
Lipoprotein Lipase
PPAR - Gamma
ADIPOKINE LEVELS
Leptin: lower in VDR-null mice on HCa diet and much lower in HF diet
Adiponectin: On the HF diet, mRNA expression was reduced in WT mice
Resistin: no difference between mice on HCa or HFResistin: no difference between mice on HCa or HF
PLASMA LIPID LEVELS
Female: No difference in plasma triglycerides, cholesterol, free-fatty acids on both diets
Male: VDR-null mice had lower triglycerides and cholesterol
Triglyceride
Male: VDR-null mice had lower triglycerides and cholesterol on both diets
Top Image: hubpages.com/hub/Triglycerides-can-kill
Bottom Image: www.3dchem.com/molecules.asp?ID=92
(NOT DUE TO: food intake, increased physical activity, decreased intestinal absorption, or increased thyroid stimulating hormone levels)
Cholesterol
B-Oxidation
•Carnitine palmitolytransferase II (CPTII) protein is responsible for transporting fatty acids into the mitochondrial matrix
• CPTII expression higher in the WAT of VDR-null miceCPTII mRNA increased too
•Increased rate of B-oxidation in adipocytes helps explain increased level of lipids in VDR-null mice
•Suggests more fatty acids are oxidized, which leads to higher basal energy expenditure
ØUCP expression in BAT was increased in VDR-null mice, the difference was higher when mice where on the HF diet
ØThe expression of the B-adrenergic receptor 3 was unchanged B/c AdrB3 is known to directly regulate UCPsSuggests Vit D directly regulates UCPs
ØDouble Check: treated VDR-null and WT mice with 1,25(OH)2D3As expected, found no effect on VDR-null cells
UNCOUPLING PROTEINS
As expected, found no effect on VDR-null cells
ØVDR transcript was missing in VDR-null mice à Vit D directly targets fat
High Calcium Diet High Fat Diet
� VDR-Knockout Phenotype:◦ Lower fat mass & lower plasma lipid levels
� Vit D-Receptor is involved in Energy Metabolism◦ VDR-null mice had higher energy expenditure as ◦ VDR-null mice had higher energy expenditure as shown by the indirect calorimetric measurement
� Possible Mechanism for this involvement:◦ Vit D directly downregulates UCP expression in BAT
� This Alteration of E Metabolism explains:◦ The lower adiposity and lower plasma lipid profile
� Studies should look at VDR in other body tissues to further understand its role in total body energy metabolism.
� Also, look at the difference btwn in vivo and in vitro
� By better understanding total body energy metabolism, we may be one step closer to helping understand and treat obesity.
� May eventually, lead to a way to alter energy metabolism
hubpages.com/hub/Triglycerides-can-kill
http://science.kukuchew.com/wp-content/uploads/2009/02/obesity_surgery.jpg
http://ajpendo.physiology.org/cgi/content/full/296/4/E820
http://www.cdc.gov/obesity/data/trends.html
Wong, Kari. E. “Involvement of the vitamin D receptor in energy metabolism: regulation of uncoupling proteins.” Division of Biological Sciences. Dept.
of Medicine Metabolism and Nutrition. Chicago, Illinois. 22 Jan. 2009
www.3dchem.com/molecules.asp?ID=92
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