Machine learning-guided chondrocyte membrane-camouflaged lipid nanoparticles for intra-articular SOX9 mRNA therapy of...

Osteoarthritis (OA) progression involves cartilage matrix loss and persistent inflammation. This study developed a machine learning-guided and chondrocyte membrane-camouflaged lipid nanoparticle carrying messenger RNA (CM-LNP@mRNA) platform for intra-articular SOX9 delivery. Random forest analysis identified the nitrogen-to-phosphorus and SM-102 ratios as primary determinants with feature importance values of 0.57 and 0.32 respectively. Following ML-guided formulation selection and experimental membrane-coating optimization, the final CM-LNP@mRNA formulation showed an encapsulation efficiency of 95.50% and a particle size of 133.70 nm. Compared with the conventional reference formulation prepared under the same final coating condition, encapsulation efficiency increased from 89.20% to 95.50% and particle size decreased from 145.40 nm to 133.70 nm. Membrane coating shifted the zeta potential from -25.57 mV to -35.07 mV. This transition provided biophysical evidence of successful surface modification. In interleukin-1β-stimulated chondrocytes, CM-LNP@mRNA increased the relative expression of Col2a1 and Acan from 0.20 to 0.33 and from 0.50 to 0.73, respectively, while reducing the relative expression of Mmp3 and Adamts5 from 10.50 to 7.80 and from 4.00 to 2.50, respectively. These alterations indicated a shift toward a matrix-preserving transcriptional state. Downstream matrix metalloproteinase 3 and prostaglandin E2 concentrations decreased from 37.10 ng/mL to 18.50 ng/mL and from 113.70 pg/mL to 76.50 pg/mL by day 7. This reduction demonstrated effective suppression of catabolic and inflammatory activity. In OA rats, CM-LNP@mRNA reduced the osteophyte volume from 4.00 mm³ to 2.00 mm³ and prolonged the thermal response latency from 7.50 s to 11.80 s. These improvements linked cellular metabolic regulation to functional joint recovery. These findings establish a strategy integrating formulation optimization with biomimetic membrane coating to modulate the OA microenvironment.