# Targeting GPR68 as a novel modulator of osteoarthritis

> **NIH NIH R03** · EMORY UNIVERSITY · 2022 · $128,200

## Abstract

Clinical premise: Osteoarthritis (OA), the most common form of joint disorder, is a debilitating joint disease
involving progressive cartilage degeneration, with no disease modifying therapy available. Thus, efforts to
elucidate new molecular target and mechanism that can be utilized to prevent and/or treat the OA are of utmost
importance. Recently, an orphan GPCR protein-the GPR68 has been identified and characterized in
musculoskeletal tissues including bone and intervertebral disc, however its role in cartilage and OA is not known.
Our preliminary analyses demonstrate that GPR68 was robustly expressed in cartilage derived from human OA
patient and experimental model of OA in mice, indicating its role in OA pathogenesis. Using IDG/Pharos
database, we identified `Inflammatory Process' a major GO term (Gene Ontology) associated with GPR68. In
this project, we propose to establish the functional role of GPR68 in inflammatory signaling in osteoarthritic
chondrocytes and ascertain its significance in OA pathogenesis.
Scientific premise: We provide compelling preliminary evidence of the following: 1. GPR68 was robustly
expressed in human and mice cartilage and its expression was significantly higher in OA cartilage compared to
healthy cartilage; 2. GPR68 mRNA and protein levels was higher in high-grade OA cartilage as compared to
low-grade OA cartilage; 3. Mechanical stimulation of primary human chondrocytes resulted in increased
expression of GPR68; 4. Gpr68 expression was significantly higher in mice cartilage of surgically induced OA
(DMM surgery) as compared to sham control; 5. IL1β stimulation of OA chondrocytes resulted in significantly
increased expression of GPR68; 6. Knockdown of GPR68 in OA chondrocytes alleviated IL-1β induced
expression of inflammatory genes.
Hypothesis: GPR68 mediates inflammatory and catabolic effects leading to OA progression and thus
suppression of GPR68 attenuates the inflammation and matrix degeneration in OA joints.
Specific objectives: To verify this hypothesis, we will establish the functional role of GPR68 in inflammatory
and catabolic pathways in human OA chondrocytes (Aim1). We will then define the role of Gpr68 in cartilage
degradation in surgically induced osteoarthritis in vivo (Aim 2).
Impact: Identifying the pathophysiological role of GPR68 in the regulation of chondrocyte inflammatory and
catabolic activity will lead to the potential development of novel therapeutic strategies to treat OA, thus laying
the foundation for future clinical study to establish a novel effective OA modifying drug.

## Key facts

- **NIH application ID:** 10452259
- **Project number:** 1R03TR003669-01A1
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** Mohd Nazir Khan
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $128,200
- **Award type:** 1
- **Project period:** 2022-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10452259

## Citation

> US National Institutes of Health, RePORTER application 10452259, Targeting GPR68 as a novel modulator of osteoarthritis (1R03TR003669-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10452259. Licensed CC0.

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