PiRNA hsa_piR_019914 Promoted Chondrocyte Anabolic Metabolism By Inhibiting LDHA-Dependent ROS Production.

Objectives: Osteoarthritis (OA) is the most common joint disease. The occurrence and progression of OA are regulated by epigenetics. A large number of studies have shown the important regulatory role of noncoding RNAs in joint diseases. As the largest class of noncoding small RNAs, the importance of piRNAs in many diseases, especially cancer, has been increasingly recognized. However, few studies have explored the role of piRNAs in OA. Our study showed that hsa_piR_019914 decreased significantly in OA. This study aimed to demonstrate the role of hsa_piR_019914 as a potential biological target of OA in chondrocytes.

Design: The GEO database and bioinformatics analysis were used for a series of screenings, and the OA model using human articular chondrocytes (C28/I2 cells), SW1353 cells under inflammatory factor stimulation was used to determine that hsa_piR_019914 was significantly downregulated in OA. Overexpression or inhibition of hsa_piR_019914 in C28/I2 cells was achieved by transfecting mimics or inhibitors. The effect of hsa_piR_019914 on the biological function of chondrocytes was verified by qPCR, flow cytometry, and colony formation assays in vitro. The target gene of hsa_piR_019914, lactate dehydrogenase A (LDHA), was screened by small RNA sequencing and quantitative polymerase chain reaction (qPCR), LDHA was knocked out in C28/I2 cells by the transfection of siRNA LDHA, and the relationship between hsa_piR_019914, LDHA, and reactive oxygen species (ROS) production was verified by flow cytometry.

Results: The piRNA hsa-piR-019914 was significantly downregulated in osteoarthritis (OA). Hsa-piR-019914 reduced inflammation-mediated chondrocyte apoptosis and maintained cell proliferation and clone formation in vitro. Hsa-piR-019914 reduced the production of LDHA-dependent ROS through targeted regulation of LDHA expression, maintained chondrocyte-specific gene expression of ACAN and COL2, and inhibited the gene expression of MMP3 and MMP13.

Conclusions: Collectively, this study showed that hsa_piR_019914 was negatively correlated with the expression of LDHA, which mediates ROS production. Under the stimulation of inflammatory factors, overexpression of hsa_piR_019914 had a protective effect on chondrocytes in vitro, and the absence of hsa_piR_019914 exacerbated the negative effect of inflammation on chondrocytes. Studies on piRNAs provide new therapeutic interventions for OA.