# Cellular Determinants of Adipocyte Phenotype and Function

> **NIH NIH R56** · UNIVERSITY OF CHICAGO · 2021 · $164,000

## Abstract

PROJECT SUMMARY
 Brown and beige adipocytes play key roles in mediating adaptive thermogenesis and controlling energy
metabolism. In response to cold exposure, beige adipocytes develop within subcutaneous white adipose tissue
(sWAT), and together with brown adipose tissue (BAT), contribute to the thermogenic response. As a result,
there is intense interest in elucidating the mechanism by which cold induces “beiging” or further “browning” of
adipocytes, and identifying putative downstream targets that mediate thermogenesis and energy expenditure
as a therapeutic strategy for addressing metabolic diseases such as obesity and diabetes. In preliminary
studies, we found that exposure of mice to cold (4oC) induces the rapid activation of ROCK2; increases beiging
of sWAT; and upregulates the thermogenic gene program consisting of Pgc-1, Ucp1, and Prdm16. Mutant
mice lacking Rock2 in adipocytes (adipo-Rock2–/– mice) failed to develop cold-induced beiging of sWAT;
exhibited reduced thermogenic activity; and have cold intolerance. Interestingly, we also found that BAT of
adipo-Rock2–/– mice have less mitochondria content. The mechanism may be due, in part, to decreased
mitochondrial biogenesis through the loss of ROCK2-induced myocyte enhancer factor (MEF)-2A
phosphorylation and activation. The overall aim of this proposal, therefore, is to determine how adipocyte
Rock2 could regulate energy metabolism and obesity through the induction of beiging and thermogenesis.
 Specific aim 1 will test the hypothesis that adipocyte Rock2 mediates thermogenesis through the
induction of beiging and the thermogenic gene program in sWAT. Single-cell transcriptome and proteome
analyses will be performed on adipocytes from sWAT to help delineate Rock2-mediated signaling pathways
that could regulate cold-induced beiging and thermogenesis.
 Specific aim 2 will test the hypothesis that Rock2 mediates BAT thermogenesis through MEF2A-
dependent mitochondrial biogenesis. Using reconstituted Mef2a–/– mouse embryonic fibroblasts (MEFs) or BA,
we will determine the role of MEF2A in Pgc-1 gene transcription. We will also perform ATAC/ChIP/RNA-seq
to assess for potential enrichment of phosphorylated MEF2A-binding regions in promoters of genes that are
involved in mitochondrial biogenesis.
 Specific aim 3 will test the hypothesis that adipocyte Rock2-Mef2a pathway is critical for energy
metabolism and diet-induced obesity (DIO). We will profile metabolic changes in adipo-Rock2–/– (loss-of-
function) and adipo-caRock (gain-of-function) mice on high fat diet (HFD). We will also generate mice with
mutations in Rock2-dependent phosphorylation sites on MEF2A using CRISPR-Cas9 gene editing or Cre/loxP
technology. These Mef2a mutant mice, if viable, will be studied to determine their response to cold and HFD
with regards to beiging, mitochondrial biogenesis, and thermogenesis.

## Key facts

- **NIH application ID:** 10410997
- **Project number:** 1R56DK129644-01
- **Recipient organization:** UNIVERSITY OF CHICAGO
- **Principal Investigator:** JAMES Kuang-Jan LIAO
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $164,000
- **Award type:** 1
- **Project period:** 2021-08-19 → 2023-08-18

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10410997

## Citation

> US National Institutes of Health, RePORTER application 10410997, Cellular Determinants of Adipocyte Phenotype and Function (1R56DK129644-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10410997. Licensed CC0.

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