LRRC15 Silencing Reprograms Costal Chondrocytes with Enhanced Anti-Hypertrophic Capacity for Functional Cartilage...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Cell Biology

Background:

• Costal chondrocytes (CCs) show potential for cartilage tissue engineering but tend to undergo hypertrophic differentiation.
• Leucine-rich repeat-containing protein 15 (LRRC15) is identified as a key regulator of this hypertrophic pathway in CCs.

Purpose of the Study:

• To investigate the role of LRRC15 in CC hypertrophic differentiation.
• To develop an enhanced cell-based therapy for cartilage regeneration using LRRC15-silenced CCs and an injectable hydrogel system.

Main Methods:

• RNA sequencing to identify LRRC15 as a regulator.
• Silencing LRRC15 in CCs (shLRRC15@CCs) and evaluating their chondrogenic potential in vitro and in vivo.
• Encapsulating shLRRC15@CCs in a thermosensitive poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PLEL) hydrogel for injectable delivery.
• Transcriptome profiling to elucidate the mechanism of LRRC15 knockdown.

Main Results:

• LRRC15 silencing suppressed hypertrophic markers and enhanced matrix synthesis in CCs.
• shLRRC15@CCs maintained chondrogenic phenotype under inflammation and promoted cartilage regeneration in a rat model.
• The injectable PLEL hydrogel facilitated minimally invasive delivery and sustained cell retention.
• LRRC15 knockdown was shown to attenuate AP-1 transcriptional activity by downregulating FOS expression.

Conclusions:

• LRRC15 is a critical suppressor of hypertrophic differentiation in CCs.
• The combination of LRRC15-silenced CCs within an injectable hydrogel (PLEL@shLRRC15-CCs) offers a synergistic therapy for cartilage repair.
• This approach provides intrinsic anti-hypertrophic properties and enables minimally invasive delivery for enhanced cartilage regeneration.