Role of lncRNA XIST/miR-146a Axis in Matrix Degradation and Apoptosis of Osteoarthritic Chondrocytes Through Regulation of MMP-13 and BCL2.

in Biology by Sara Cheleschi, Nicola Mondanelli, Iole Seccafico, Roberta Corsaro, Elena Moretti, Giulia Collodel, Antonella Fioravanti

TLDR

  • The study found that XIST plays a role in osteoarthritis by regulating cell viability, apoptosis, and matrix degradation, and that the XIST/miR-146a axis is a potential therapeutic target.

Abstract

Growing evidence demonstrates the critical roles of long non-coding RNAs (lncRNAs) in osteoarthritis (OA) pathogenesis. The lncRNA XIST is one of the most commonly studied; however, its function remains unclear. This study aimed to research the molecular mechanism of XIST in human OA chondrocytes. Cells were transfected with small interfering RNA against XIST or with a microRNA (miR)-146a inhibitor in the presence of interleukin (IL)-1β. Viability was detected using MTT; apoptosis using cytometry; and XIST, miR-146a, B-cell lymphoma (BCL)2, and metalloproteinase (MMP)-13 expression using real-time PCR. The analysis of p50 and p65 nuclear factor (NF)-κB was conducted using PCR and immunofluorescence. Our findings showed that XIST was highly expressed in OA chondrocytes when compared to T/C-28a2 lines. Furthermore, XIST silencing significantly promoted survival and limited apoptosis, with a concomitant over expression of BCL2, reduction in MMP-13 mRNA, and NF-κB activation after IL-1β stimulus. Conversely, miR-146a was significantly down-regulated in OA cells, while its levels were increased following XIST silencing; moreover, miR-146a inhibition induced opposite results to those caused by XIST. Finally, the down-regulation of XIST was correlated to the over-expression of miR-146a, with a consequent modulation of BCL2, MMP-13, and NF-κB. This study suggests an influence of the XIST/miR-146a axis on the viability, apoptosis, and matrix degradation occurring in OA.

Overview

  • The study aimed to investigate the molecular mechanism of XIST in human OA chondrocytes, a type of cell that plays a crucial role in osteoarthritis.
  • The researchers used a combination of techniques, including real-time PCR, PCR, and immunofluorescence, to examine the expression of XIST, miR-146a, BCL2, and MMP-13 in human OA chondrocytes.
  • The study sought to identify the potential connections between XIST, miR-146a, and key molecules involved in osteoarthritis, such as BCL2, MMP-13, and NF-κB.

Comparative Analysis & Findings

  • The researchers found that XIST was highly expressed in OA chondrocytes compared to T/C-28a2 lines, indicating a potential role in osteoarthritis.
  • XIST silencing significantly promoted survival and limited apoptosis, with a concomitant overexpression of BCL2, reduction in MMP-13 mRNA, and NF-κB activation after IL-1β stimulus.
  • Conversely, miR-146a was significantly down-regulated in OA cells, while its levels were increased following XIST silencing; the down-regulation of XIST was correlated to the over-expression of miR-146a.

Implications and Future Directions

  • The study suggests that the XIST/miR-146a axis plays a crucial role in the pathogenesis of osteoarthritis, particularly in terms of cell viability, apoptosis, and matrix degradation.
  • Future studies could explore the potential therapeutic applications of modulating the XIST/miR-146a axis in osteoarthritis, such as developing novel treatments that target this axis.
  • The study's findings also highlight the need for further research into the molecular mechanisms underlying XIST's role in osteoarthritis, which could lead to a better understanding of the disease and the development of more effective treatments.
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