# Molecular Mechanisms of Chondrocyte Hypertrophy Mediated by Physical Cues and Therapeutic Strategies in Osteoarthritis

## TL;DR

This paper reviews how physical cues influence chondrocyte hypertrophy in osteoarthritis and explores therapeutic strategies to target this process.

## Contribution

It provides an integrated mechanobiological framework linking physical cues to chondrocyte behavior and disease-modifying treatment opportunities.

## Key findings

- Chondrocyte hypertrophy is driven by mechanical cues and is a key event in cartilage degeneration.
- ECM properties like stiffness and viscoelasticity influence hypertrophy in a zone- and stage-dependent manner.
- Mechanosensitive pathways and structures transduce biophysical signals into intracellular responses.

## Abstract

Osteoarthritis (OA) is a multifactorial degenerative joint disease in which aberrant mechanical cues act in concert with metabolic dysregulation and chronic low-grade inflammation, with chondrocyte hypertrophy representing a key pathological event driving cartilage degeneration. Alterations in extracellular matrix (ECM) properties—including mechanical loading, stiffness and viscoelasticity, topological organization, and surface chemistry—regulate hypertrophic differentiation and matrix degradation in a zone-, stage-, and scale-dependent manner. Microscale measurements often reveal localized stiffening in superficial zones during early OA, whereas bulk tissue testing can show softening or heterogeneous changes in deeper zones or advanced stages, highlighting the context-dependent nature of ECM mechanics. These biophysical signals are sensed by integrin-based adhesion complexes, primary cilia, mechanosensitive ion channels (TRP/Piezo), and the actin cytoskeleton–nucleus continuum, and are transduced into intracellular pathways with zone- and stage-specific effects, governing chondrocyte fate under physiological and osteoarthritic conditions. Mechanism-based anti-hypertrophic strategies include biomimetic scaffold design for focal defects, dynamic mechanical stimulation targeting early OA, and multimodal approaches integrating mechanical cues with biochemical factors, gene modulation, drug delivery, or cell-based therapies. Collectively, this review provides an integrated mechanobiological framework for understanding cartilage degeneration and highlights emerging opportunities for disease-modifying interventions targeting chondrocyte hypertrophy.