# Biomechanics of Cartilage: Roles of Decorin in ECM Assembly and Degradation

> **NIH NIH R01** · DREXEL UNIVERSITY · 2024 · $326,990

## Abstract

PROJECT SUMMARY
 The development of novel cartilage regeneration and osteoarthritis (OA) treatments is limited by our
incomplete understanding of how certain molecular activities in cartilage extracellular matrix (ECM) are linked
to its matrix assembly and biomechanical functions. This project will study the activities of decorin, a small
leucine rich proteoglycan (SLRP), which appears to be critical for the assembly and stability of the aggrecan
network, a major constituent of cartilage ECM. The overall objective is to determine the roles of decorin in
regulating the assembly of the aggrecan network in healthy and degenerative cartilage. Our central hypothesis
is that decorin acts as a “physical linker” to regulate the assembly of the aggrecan network in cartilage ECM,
and this role enables the establishment of the normal biomechanical function of cartilage during joint
development, and delays cartilage degeneration in OA by increasing the retention of fragmented aggrecan.
 We will elucidate the roles of decorin in normal cartilage ECM assembly (Aim 1) and in OA-associated
cartilage degradation (Aim 2), respectively. In Aim 1, we will first determine whether decorin is essential for the
proper biomechanical function of normal cartilage during post-natal growth. Next, we will determine whether
decorin increases the retention of aggrecan in the forming neo-matrix of chondrocytes under dynamic loading,
and if decorin also regulates chondrocyte anabolic response to growth factors. In Aim 2, we will first determine
whether decorin slows down cartilage degradation and OA progression using two murine OA models, including
naturally occurring OA in aged mice and injury-induced post-traumatic OA in the destabilization of the medial
meniscus (DMM) model. Next, we will determine if decorin increases the retention of aggrecan fragments in
degenerative cartilage, and if decorin also directly impacts chondrocyte catabolism in response to inflammatory
factors. A number of innovative approaches will be utilized. Using cartilage-specific decorin inducible knockout
mice, we will delineate decorin activities during normal cartilage homeostasis and those during the progression
of OA. Applying atomic force microscopy (AFM)-nanomechanical tests, we will quantify the mechanical
changes of cartilage as a result of decorin deficiency. By combining these approaches, we will elucidate the
roles of decorin in regulating the structure and function of normal cartilage, and the degradation of cartilage
during OA onset and progression. Successful completion of this study will establish a new structure-mechanics
principle of decorin-mediated aggrecan network assembly in the cartilage ECM. This will direct our future
studies to improve cartilage regeneration and to slow down OA progression by modulating the activity and
availability of native decorin, as well as the design and delivery of decorin-biomimetic synthetic molecules.

## Key facts

- **NIH application ID:** 10756102
- **Project number:** 5R01AR074490-05
- **Recipient organization:** DREXEL UNIVERSITY
- **Principal Investigator:** Lin Han
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $326,990
- **Award type:** 5
- **Project period:** 2019-08-01 → 2025-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10756102

## Citation

> US National Institutes of Health, RePORTER application 10756102, Biomechanics of Cartilage: Roles of Decorin in ECM Assembly and Degradation (5R01AR074490-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10756102. Licensed CC0.

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