Related Experiment Video
Updated: Nov 6, 2025
Software-Assisted Quantitative Measurement of Osteoarthritic Subchondral Bone Thickness
Published on: March 18, 2022
Adenosine A2A receptor null chondrocyte transcriptome resembles that of human osteoarthritic chondrocytes
Cristina M Castro1, Carmen Corciulo2,3, Benjamin Friedman4
1Department of Medicine, Beth Israel Deaconess Medical Center (BIDMC), Boston, MA, USA.
Abstract:
Adenosine signaling plays a critical role in the maintenance of articular cartilage and may serve as a novel therapeutic for osteoarthritis (OA), a highly prevalent and morbid disease without effective therapeutics in the current market. Mice lacking adenosine A2A receptors (A2AR) develop spontaneous OA by 16 weeks of age, a finding relevant to human OA since loss of adenosine signaling due to diminished adenosine production (NT5E deficiency) also leads to development of OA in mice and humans. To better understand the mechanism by which A2AR and adenosine generation protect from OA development, we examined differential gene expression in neonatal chondrocytes from WT and A2AR null mice. Analysis of differentially expressed genes was analyzed by KEGG pathway analysis, and oPOSSUM and the flatiron database were used to identify transcription factor binding enrichment, and tissue-specific network analyses and patterns were compared to gene expression patterns in chondrocytes from patients with OA. There was a differential expression of 2211 genes (padj<0.05). Pathway enrichment analysis revealed that pro-inflammatory changes, increased metalloprotease, reduced matrix organization, and homeostasis are upregulated in A2AR null chondrocytes. Moreover, stress responses, including autophagy and HIF-1 signaling, seem to be important drivers of OA and bear marked resemblance to the human OA transcriptome. Although A2AR null mice are born with grossly intact articular cartilage, we identify here the molecular foundations for early-onset OA in these mice, further establishing their role as models for human disease and the potential use of adenosine as a treatment for human disease.
Insights
Adenosine signaling, particularly via adenosine A2A receptors (A2AR), is crucial for protecting articular cartilage. Loss of A2AR function in mice leads to osteoarthritis (OA) development, highlighting adenosine
Area of Science:
- Biochemistry
- Molecular Biology
- Rheumatology
Background:
- Adenosine signaling is vital for articular cartilage health and presents a potential therapeutic target for osteoarthritis (OA).
- Current OA treatments are limited, necessitating research into novel therapeutic strategies.
- Genetic deficiencies in adenosine production or signaling, such as loss of adenosine A2A receptors (A2AR), are linked to OA development in mice and humans.
Purpose of the Study:
- To elucidate the molecular mechanisms underlying joint protection by A2AR and adenosine generation.
- To investigate the role of A2AR signaling in the early pathogenesis of osteoarthritis.
- To compare gene expression patterns in A2AR-deficient mice with human OA to identify conserved disease pathways.
Main Methods:
- Differential gene expression analysis was performed on neonatal chondrocytes from wild-type (WT) and A2AR-null mice.
- KEGG pathway analysis identified enriched biological pathways.
- Transcription factor binding enrichment was assessed using oPOSSUM and the flatiron database.
- Network analyses compared mouse gene expression patterns to those from human OA chondrocytes.
Main Results:
- A total of 2211 differentially expressed genes were identified in A2AR-null chondrocytes (padj<0.05).
- Pathway analysis revealed upregulation of pro-inflammatory mediators, increased matrix-degrading metalloproteases, and reduced matrix organization and homeostasis in A2AR-null chondrocytes.
- Stress responses, including autophagy and HIF-1 signaling, were identified as key drivers of OA pathogenesis, mirroring patterns in human OA.
Conclusions:
- A2AR signaling is essential for maintaining articular cartilage homeostasis and preventing OA development.
- A2AR-null mice exhibit molecular changes indicative of early OA, validating their use as a model for human disease.
- These findings support the therapeutic potential of targeting adenosine signaling for OA treatment.
Related Concept Videos
01:31Adrenergic Receptors: ɑ Subtype
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase...
02:36RNA Polymerase II Accessory Proteins