Developmental dynamics mimicking inversely engineered pericellular matrix for articular cartilage regeneration.

The mechanical mismatch of scaffold matrix-mesenchymal stem cells (MSCs) has been a longstanding issue in the clinical application of MSC-based therapy for articular cartilage (AC) regeneration. Existing tissue-engineered scaffolds underestimate the importance of the natural chondrocyte pericellular matrix (PCM). Here, we reveal the temporal and spatial characteristics of collagen distribution around the chondrocytes. Next, we demonstrate a rationally designed layer-by-layer single-cell encapsulation system which can mimic PCM mechanical responses and enhance MSC chondrogenesis via reestablished the mechanical coupling of PCM-like primitive matrix and chondrocytes. This successfully simulates the temporal and spatial characteristics of collagen secretion. Through investigation of the micromechanical environment of the cells and full-atom simulation analysis of TRPV4, we determine the specific mechanisms by which cellular mechanical forces near the cell are converted into biological signals. The TRPV4-YAP/TAZ-PI3K-Akt signaling pathway is involved in MSC cartilage formation through a joint analysis of the mRNA sequencing and spatial transcriptome results. In a rat model of articular cartilage defects, our inversely engineered pericellular matrix-encapsulated MSC-loaded scaffolds show regenerative performance that are superior to those of scaffolds loaded with only MSCs. These results demonstrate the feasibility of using a PCM-mimicking system to improve MSC chondrogenesis and the efficacy of AC repair.