Article Text
Abstract
Objectives We recently identified microRNA-181a-5p (miR-181a-5p) as a critical mediator involved in the destruction of lumbar facet joint (FJ) cartilage. In this study, we tested if locked nucleic acid (LNA) miR-181a-5p antisense oligonucleotides (ASO) could be used as a therapeutic to limit articular cartilage degeneration.
Methods We used a variety of experimental models consisting of both human samples and animal models of FJ and knee osteoarthritis (OA) to test the effects of LNA-miR-181a-5p ASO on articular cartilage degeneration. Histopathological analysis including immunohistochemistry and in situ hybridisation were used to detect key OA catabolic markers and microRNA, respectively. Apoptotic/cell death markers were evaluated by flow cytometry. qPCR and immunoblotting were applied to quantify gene and protein expression.
Results miR-181a-5p expression was increased in human FJ OA and knee OA cartilage as well as injury-induced FJ OA (rat) and trauma-induced knee OA (mouse) cartilage compared with control cartilage, correlating with classical OA catabolic markers in human, rat and mouse cartilage. We demonstrated that LNA-miR-181a-5p ASO in rat and mouse chondrocytes reduced the expression of cartilage catabolic and chondrocyte apoptotic/cell death markers in vitro. Treatment of OA-induced rat FJ or mouse knee joints with intra-articular injections of in vivo grade LNA-miR-181a-5p ASO attenuated cartilage destruction, and the expression of catabolic, hypertrophic, apoptotic/cell death and type II collagen breakdown markers. Finally, treatment of LNA-miR-181a-5p ASO in cultures of human knee OA chondrocytes (in vitro) and cartilage explants (ex vivo) further demonstrated its cartilage protective effects.
Conclusions Our data demonstrate, for the first time, that LNA-miR-181a-5p ASO exhibit cartilage-protective effects in FJ and knee OA.
- osteoarthritis
- treatment
- chondrocytes
- microRNA
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Footnotes
Handling editor Josef S Smolen
Contributors AN was involved in the conception and design of the study, acquisition of data, analysis and interpretation of data, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript. YRR was involved in the design of the study, performed spine surgery in patients with LSS or LDH, provided tissues, performed MRI rading, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript. SN and AS performed animal surgeries to induce osteoarthritis models, inject miRNA antisense oligonucleotide into rat facet joint and mouse knee joints, tissue dissections along with AN, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript. FZ was involved to perform flow cytometry along with AN, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript. ER was involved to perform histology for making sections and safranin O staining, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript. SAA, RK, NH, AVP, NNM, RG and JSR were involved in the interpretation of data, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript. MK was involved in the conception and design of the study, interpretation of data, drafting the article, revising it critically for important intellectual content and approved final version of the manuscript.
Funding This study was supported by grants to MK from the Krembil Foundation, the Canadian Institute of Health Research (FRN: 156299) and Campaign to Cure Arthritis via the Toronto General and Western Foundation, University Health Network, Toronto. AN and SAA are recipients of postdoctoral fellowship funding from the Krembil Research Institute (University Health Network).
Competing interests A US provisional patent application (62/299,305, filed 24 February 2016) and a PCT international patent application (PCT/CA2017/000019, filed 31 January 2017) have been filed in respect of therapeutic and diagnostic uses of miRNA-181a-5p.
Patient consent Obtained.
Ethics approval Human facet and knee cartilage were obtained under the institutional approval.
Provenance and peer review Not commissioned; externally peer reviewed.