cAMP response element‐binding (CREB) recruitment following a specific CpG demethylation leads to the elevated expression of the matrix metalloproteinase 13 in human articular chondrocytes and osteoarthritis

Abstract

Osteoarthritis is a degenerative joint disease characterized by a progressive and irreversible loss of the articular cartilage, due in main part to the cleavage of type II collagen within the matrix by the enzyme matrix metalloproteinase (MMP)13. Here, we examined the methylation status of MMP13 promoter and report the demethylation of specific CpG dinucleotides within its promoter in osteoarthritic compared to normal cartilage, which correlates with increased MMP13 expression. Of the promoter CpG sites examined, the -104 CpG was consistently demethylated following treatment of human articular chondrocytes with 10 μM DNA-methyltransferase inhibitor 5-aza-2'-deoxycytidine, again correlating with increased MMP13 expression. Methylation of the -104 CpG site resulted in reduced promoter activity in the chondrosarcoma cell line SW1353 as shown by CpG-free luciferase reporter. Using electrophoretic mobility shift assays, we identified CREB as the regulating factor able to only bind to the MMP13 promoter when the -104 CpG is demethylated, and confirmed this binding by chromatin immunoprecipitation. Finally, we demonstrated that CREB induces MMP13 expression only following treatment of SW1353 with 0.5 μM Ca(2+) ionophore A23187. In summary, the -104 CpG is demethylated in osteoarthritic cartilage, correlating with the elevated MMP13 expression and cartilage destruction, providing a highly novel link between epigenetic status and arthritic disease.

cAMP-response Element-binding Protein (CREB) and NF-κB Transcription Factors Are Activated during Prolonged Hypoxia and Cooperatively Regulate the Induction of Matrix Metalloproteinase MMP1

“…NF-B is reported to also induce several MMPs upon cytokine activation, including MMP9, MMP13, and MT1-MMP (10,32,33). Similarly, CREB induces MMP2, MMP9, and MMP13 (34,35). Therefore, synchronized activation of CREB and NF-B during prolonged hypoxia might control the timing of metastasis, which is mediated by the orchestration of MMP1 and other MMPs (9).…”

The role of Alk-1 and Alk-5 in the mechanosensing of chondrocytes

“…The epigenetic state of the Sox9 promoter has been described to change during the process of OA [21]. In the same way, promoters for several metalloproteinases have been described as less methylated in OA-derived samples [22][23][24]. However, other studies have yielded results that could not demonstrate significant gene methylation in the aggrecan promoter of aged and OA chondrocytes [25].…”

The first international workshop on the epigenetics of osteoarthritis

“…Alterations in DNA methylation patterns have been observed in OA chondrocytes, particularly a loss of DNA methylation at the promoters and the concurrent "unsilencing" of various OA-associated genes including MMP3, 9, and 13, ADAMTS4, IL-1β, and iNOS (14,33,34). Recently, Professor Bhutani's team reported a remarkable dysregulation of 5hmC homeostasis in patients with OA, with increases in global 5hmC levels observed in OA chondrocytes when compared to normal chondrocytes (35).…”