Adipose stem cells' niche in obesity

NIH RePORTER · VA · I01 · · view on reporter.nih.gov ↗

Abstract

Obesity continues to escalate as a significant public health problem and as the leading preventable cause of death. Stark data from COVID19 pandemic shows obesity is an independent risk factor of severity with 33% mortality rate. Obesity per se is not fatal but is the major health risk factor promoting severe diseases including cardiovascular diseases, type 2 diabetes mellitus, and certain cancers. 42% of adult population in US is obese (CDC NCHS report 2020). Healthcare costs related to obesity account for greater than 10% of total US medical expenditures and has risen to $254 billion per year (1). Alarmingly 78% of the Veteran population is obese, a notably higher percent compared to civilian population(2). Adipose tissue is an important endocrine regulator of energy homeostasis and metabolism. During adipogenesis, the adipose stem cells (ASC) differentiate into adipocytes and replenish the body’s need for new adipocytes. Normal adiposity is exaggerated in obesity and is accompanied by adipocyte hyperplasia and hypertrophy. Previously this lab demonstrated that obesity changes the human adipose stem cells’ niche such that it promotes a microenvironment conducive to developing obesity-associated comorbidities. A significant finding was that the expression of long noncoding RNAs (lncRNAs) differed in the obese ASC compared to lean subjects which contributed to the aberrant metabolic processes, insulin resistance and chronic low-grade inflammation observed in obesity. Using an unbiased transcriptomic screening, this lab identified lncRNA GAS5 as an important regulatory gene that is depleted in human obese adipose tissue, ASC and mature adipocytes compared to lean. Prior research has demonstrated that GAS5 regulates insulin receptor and glucocorticoid receptor mediated pathways. However, the importance and impact of low GAS5 levels on the metabolic pathways in obese adipocytes has not yet been thoroughly investigated. Hence, it is hypothesized that low levels of GAS5 substantially contributes to the manifestation of comorbidities associated with obesity. Towards the overarching goal to determine if GAS5 supports healthy adipocytes, the proposal will evaluate the underlying mechanisms and role of GAS5 in human obese ASC and adipocytes using a multi-disciplinary approach including pre-clinical, physiological, cellular and biochemical experiments. Specific Aim 1: Determine the role of GAS5 in ASC and adipocytes: It is hypothesized that manipulating GAS5 levels will affect the metabolic health of ASC and adipocytes. GAS5 siRNA or over-expression plasmid will be used to evaluate the genetic and metabolic parameters pertaining to adipocyte health and function. Specific Aim 2: Elucidate molecular mechanisms regulated by GAS5 in obese adipocytes: GAS5 levels are low in ASC and adipose tissue in obesity. A small molecule that stabilizes GAS5 has been recently developed. It is hypothesized that stabilizing GAS5 levels could alleviate the metabolic stress an...

Key facts

NIH application ID
10363226
Project number
2I01BX003836-05A2
Recipient
JAMES A. HALEY VA MEDICAL CENTER
Principal Investigator
Niketa A. Patel
Activity code
I01
Funding institute
VA
Fiscal year
2022
Award amount
Award type
2
Project period
2017-04-01 → 2025-12-31