TEFM drives cartilage degeneration in osteoarthritis via the ROS-AKT/NF-κB signaling axis

Objective To explore the role and underlying mechanism of mitochondrial transcription elongation factor TEFM in osteoarthritis (OA) cartilage degeneration. Methods Bioinformatics analysis based on the GSE114007 human knee cartilage dataset and two-sample Mendelian randomization (MR) analysis were performed to evaluate the association between TEFM and knee OA. Human cartilage specimens were collected to verify TEFM expression patterns. Lentivirus-mediated TEFM knockdown was performed in ATDC5 chondrocytes, and an in vitro inflammatory injury model was established by interleukin-1β (IL-1β) stimulation. The effects of TEFM on chondrocyte function were determined by RT-qPCR, Western blotting, toluidine blue staining, and immunofluorescence staining. Transcriptome sequencing (RNA-seq), reactive oxygen species (ROS) scavenging, specific pathway inhibition, and H 2 O 2 rescue assays were employed to elucidate TEFM-mediated signaling cascades. For in vivo validation, a destabilization of the medial meniscus (DMM)-induced OA mouse model was established, and adeno-associated virus serotype 9 carrying sh-TEFM (AAV9-sh-TEFM) was administered via intra-articular injection. Pathological changes in cartilage and subchondral bone were assessed by micro-CT and histological staining. Results TEFM expression was significantly upregulated in OA cartilage, and MR analysis supported a potential causal association with knee OA risk. In vitro experiments demonstrated that TEFM knockdown ameliorated chondrocyte dysfunction, attenuated mitochondrial oxidative stress, and suppressed AKT/NF-κB pathway activation. Mechanistically, NAC treatment and H 2 O 2 rescue assays verified that ROS serve as a critical upstream mediator linking TEFM to AKT/NF-κB signaling, and specific inhibitor assays further confirmed the functional necessity of the AKT/NF-κB cascade in TEFM-mediated chondrocyte injury. In vivo studies revealed that intra-articular TEFM silencing alleviated cartilage degeneration and subchondral bone pathological damage in OA mice, accompanied by inhibition of the AKT/NF-κB pathway. Conclusion TEFM facilitates OA cartilage degeneration via the ROS-AKT/NF-κB axis, which provides a novel therapeutic target for OA.