Mechanical Memory Induction by Microgrooved Hydrogels Enables Stem Cell-Driven Cartilage Repair.

Area of Science:

• Biomaterials Science
• Stem Cell Biology
• Tissue Engineering

Background:

• Cellular mechanical memory influences stem cell fate and behavior.
• The physical microenvironment plays a crucial role in stem cell differentiation, particularly during cartilage repair.
• Understanding how mechanical cues direct stem cell behavior is vital for regenerative medicine.

Purpose of the Study:

• To develop a micropattern-based method to induce mechanical memory in human synovial-derived stem cells (hSSCs).
• To investigate the optimal microgroove parameters and mechanical dosing duration for promoting chondrogenesis.
• To evaluate the efficacy of mechanically conditioned hSSCs in a mouse model of cartilage defect.

Main Methods:

• Fabrication of gelatin hydrogels with microgrooved patterns (20-200 μm) using photolithography.
• Mechanical dosing of hSSCs on patterned substrates for 3–6 days to establish mechanical memory.
• Analysis of gene and protein expression, RNA sequencing, and in vivo cartilage repair assessment in a mouse model.

Main Results:

• 50 μm groove size was optimal for promoting chondrogenesis, with longer dosing (6 days) further enhancing the effect.
• Mechanical dosing increased the expression of key chondrogenic genes (TGF-β3, Sox9, ACAN).
• Mechanically dosed hSSCs showed significantly improved cartilage repair in a mouse model, linked to cytoskeletal reconfiguration and TGF-β pathway activation.

Conclusions:

• Microgroove-patterned hydrogels can induce chondrogenic mechanical memory in hSSCs.
• This mechanical memory enhances the cartilage repair potential of hSSCs via TGF-β pathway activation.
• The developed approach presents a promising strategy for tissue engineering and regenerative medicine applications in cartilage repair.