The adipose tissues play crucial roles in regulation of lipid metabolism and overall energy balance. Whilst the white adipose tissue (WAT) sequesters excessive lipids, the brown adipose tissue (BAT) promotes energy expenditure through its ability to breakdown fat and drive thermogenesis. Aging associates with perturbations in lipid metabolism and energy imbalance that lead to the development of the metabolic syndrome. Key features of white adipose aging include decreased lipid storage and impaired lipolysis that promote fat redistribution into visceral compartments. Recent findings indicate the presence of myogenic factor 5-positive (Myf5+) progenitor-derived brown adipocyte-like cells in WAT. Our published studies have shown that this BAT-like remodeling of WAT increases energy expenditure and promotes insulin sensitivity. However, whether aging affects remodeling of WAT into a BAT-like phenotype is largely unclear. Our preliminary studies indicate a key role of autophagy in differentiation of myogenic factor 5-positive (Myf5+) progenitors into BAT, and that loss of autophagy in these progenitors remarkably suppresses BAT-like remodeling of WAT. Autophagy activity decreases with age in diverse cells, and consequently, we propose to examine whether changes in autophagy with age modify remodeling of WAT into BAT-like through effects on Myf5+ progenitors and on immune cells known to modulate tissue remodeling. The main goal of the study is to understand the contribution of autophagy to whole body lipid homeostasis and energy balance by regulating adipose remodeling in young and old organisms. We will: 1) examine whether changes with age in adipocyte lipid metabolism modify the adipose immune cells and autophagy in Myf5+ progenitors;2) determine the effect of age-related changes in autophagy in adipocytes and Myf5+ progenitors on adipose remodeling;3) explore the possible beneficial effect on whole body lipohomeostasis and energy balance of anti-aging interventions (using scheduled feeding as a novel approach, and mTOR inhibition) shared with P1, P2 and P3 of this PP, and determine if their effect is by activation of autophagy and adipose remodeling. Relevance: The metabolic syndrome affects greater than 44% of the U.S. population aged more than 50 years. Understanding the mechanisms contributing to perturbed lipid metabolism should be instrumental in developing new therapeutic strategies against the metabolic syndrome of aging. .

Public Health Relevance

The metabolic syndrome is a major health issue that affects greater than 44% of the U.S. population aged more than 50 years. In this application, we will determine whether autophagy decreases in adipocytes and adipose progenitors with age and dietary stress. We will examine how cross talk between autophagy pathways in adipocytes and adipose progenitors promotes brown adipose tissue-like remodeling of white fat, and determine the role of adipose-resident macrophages in this remodeling. We will explore the beneficial effect of anti-aging interventions on adipose remodeling and lipohomeostasis. These studies could lead to development of new therapeutic strategies against the metabolic syndrome of aging.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Program Projects (P01)
Project #
2P01AG031782-06A1
Application #
8739820
Study Section
Special Emphasis Panel (ZAG1)
Project Start
Project End
Budget Start
2014-09-15
Budget End
2015-04-30
Support Year
6
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Type
DUNS #
City
Bronx
State
NY
Country
United States
Zip Code
10461
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