# Non-canonical role of GRK2 in mediating cardiac function

> **NIH NIH R56** · DREXEL UNIVERSITY · 2021 · $630,044

## Abstract

Project Summary
Heart failure (HF) is common in patients with metabolic syndromes, most notably diabetes. In these patients,
glucose resistance and/or imbalanced peptide hormone signaling impairs glucose utilization by the heart. As the
diabetic heart increasingly resists glucose uptake, it increasingly relies on fatty acids for energy production.
However, the latter can promote lipotoxicity, prompting the heart to further rely on other more limiting substrates.
Like a car running out of fuel, the ability of the heart to utilize these metabolic substrates plays a vital role in
cardiac contraction and function, particularly during cardiac injury. This phenomenon becomes particularly
evident in diabetic patients, yet mechanisms detailing how islet dysfunction crosstalk and impact cardiac
signaling pathways remain poorly understood. Cardiac G-protein coupled Receptor Kinase-2 (GRK2) is a known
regulator of cardiac contraction and its upregulation in myocardial tissue is linked to the development of HF. In
addition to its canonical role in GPCR regulation, non-canonical GRK2 regulates metabolism that may contribute
to HF. Recent studies have reported that diabetic patients have increased GRK2 levels in the heart, but
interestingly, GRK2 levels in diabetic pancreata is decreased. As GRK2 can alter the metabolism of cardiac cells,
loss of GRK2 in pancreatic cells may disrupt metabolic processes that are important for insulin and glucagon
secretion. Since the pancreas is the sole source of insulin and glucagon, and little is known about GRK2
signaling in the pancreas, this proposal seeks to understand how GRK2 regulates metabolic signaling pathways
and hormone secretion from the pancreas, and by extension, cardiac substrate utilization and metabolism. To
answer these questions, this proposal integrates biochemical and functional techniques with three novel genetic
mouse models of GRK2, including inducible GRK2 knockout models that specifically target α or β cells in the
pancreas. This proposal hypothesizes that GRK2 regulates several metabolic signals from the pancreas to the
heart that intimately link cardiac metabolism and contractile function. Due to the specialized nature of islets, the
proposal also hypothesizes that pancreatic GRK2 signaling differs substantially from known functions of cardiac
GRK2 signaling. Specifically, this proposal will: (i) examine whether GRK2 downregulation in the pancreas alters
cardiac function and metabolism; and (ii) determine how GRK2 participates in islet function. Cardiac functional
analysis will be performed by echocardiography and pressure-volume loops. In vitro studies in adult
cardiomyocytes and primary islets will be used to delineate GRK2 mechanism of action in these cells. Glucose
dynamics and islet function will also be studied in our mouse models using glucose and insulin assays that
include tolerance tests, islet perifusions, glucose telemetry, and hyperinsulinemic/hyperglycemic clamps.
Overall, this work...

## Key facts

- **NIH application ID:** 10122065
- **Project number:** 1R56HL149887-01A1
- **Recipient organization:** DREXEL UNIVERSITY
- **Principal Investigator:** Priscila Sato
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $630,044
- **Award type:** 1
- **Project period:** 2021-09-21 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10122065

## Citation

> US National Institutes of Health, RePORTER application 10122065, Non-canonical role of GRK2 in mediating cardiac function (1R56HL149887-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10122065. Licensed CC0.

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