Parathyroid Hormone Activation of Matrix Metalloproteinase-13 Transcription Requires the Histone Acetyltransferase Activity of p300 and PCAF and p300-dependent Acetylation of PCAF

Abstract

Parathyroid hormone (PTH) regulates the transcription of many genes involved in bone remodeling in osteoblasts. One of these genes is matrix metalloproteinase-13 (MMP-13), which is involved in bone remodeling and early stages of endochondral bone formation. We have previously shown that Mmp-13 gene expression is highly induced by PTH treatment in osteoblastic UMR 106-01 cells, as well as primary osteoblasts. Here, we show that p300/CBP-associated factor (PCAF), in addition to p300 and Runx2, is required for PTH activation of Mmp-13 transcription. PCAF was increasingly recruited to the MMP-13 proximal promoter region after PTH treatment, and this was associated with an increase in RNA polymerase II recruitment and histone acetylation. In addition, PTH treatment increased the acetylation of PCAF, a process that required p300. Knockdown of PCAF, p300, or Runx2 by siRNA decreased Mmp-13 mRNA expression after PTH treatment in both UMR 106-01 cells and primary osteoblasts. We found that there is a mutual dependence between p300 and PCAF to be recruited to the Mmp-13 promoter after PTH treatment. In promoter-reporter assays, p300 and PCAF had an additive effect on PTH stimulation of MMP-13 promoter activity, and this required their histone acetyltransferase activity. Our findings demonstrate that PCAF acts downstream of PTH signaling as a transcriptional coactivator that is required for PTH stimulation of MMP-13 transcription. PCAF cooperates with p300 and Runx2 to mediate PTH activation of MMP-13 transcription. PTH2 is a peptide hormone that plays a central role in regulating serum ion concentrations. Secreted from the parathyroid glands in response to low serum calcium levels, PTH has two primary sites of action, bone and kidney. In bone, PTH stimulates the release of calcium and phosphate ions from the bone mineral matrix, leading to bone degradation such that PTH is classically known as a catabolic agent in bone remodeling.However, when administered intermittently, PTH has an anabolic effect that leads to increased bone mass. Binding of PTH to its receptor, PTH1R, on the surface of osteoblasts leads to the activation of many different signaling pathways, including protein kinase A (PKA)-and protein kinase C (PKC)-dependent pathways, as well as calcium ion channels (reviewed in Ref. 1). This eventually leads to a significant change in gene expression in osteoblasts (2). Microarray analyses from our laboratory demonstrated that the catabolic effect of PTH on bone predominantly occurs through PKA-dependent signaling (3).MMP-13 is a collagenase that is expressed in chondrocytes, osteoblasts, and osteocytes. It plays an essential role in early stages of endochondral bone formation, and its expression is increased in pathological conditions such as osteoarthritis, rheumatoid arthritis, and tumor metastasis (4 -6). Mmp-13 gene expression is highly stimulated by PTH in osteoblastic UMR 106-01 cells (7), as well as in vivo (8). The relevance of MMP-13 and PTH has been demonstrated in vivo by the decreased expression of MMP-...

Sirtuin 1 Is a Negative Regulator of Parathyroid Hormone Stimulation of Matrix Metalloproteinase 13 Expression in Osteoblastic Cells

“…Under basal conditions, gene transcription of Mmp13 is repressed by the presence of HDAC4, which binds to Runx2 at the runt domain binding site (15). PTH treatment causes HDAC4 to dissociate from Runx2 on the Mmp13 promoter, and Runx2 then recruits the histone acetyltransferases, p300 and PCAF (13,14). Newly synthesized c-Fos/c-Jun subsequently bind to the AP-1 site and interact with CBP and with proteins bound to Runx2, allowing maximal transcription of Mmp13 (58).…”

“…In response to PTH, Mmp13 gene transcription was significantly attenuated by mutation of AP-1 binding sites (12). We have previously shown that PTH stimulation of MMP13 expression is regulated by histone acetylases p300, p300/CBPassociated factor (PCAF), and histone deacetylase 4 (HDAC4) (13)(14)(15).…”

Lung Tumor-associated Osteoblast-derived Bone Morphogenetic Protein-2 Increased Epithelial-to-Mesenchymal Transition of Cancer by Runx2/Snail Signaling Pathway

“…Runx2 complex, together with co-regulatory factors SMADs and other co-activator and co-repressor proteins, regulate target gene transcription (36). p300, a histone acetyltransferase, has been reported to interact with Runx2 and to subsequently regulate the expression of osteocalcin and MMP-13 (37,38). In addition, p300 also acts as a stabilizer of Runx2 via acetylation (39).…”

Chromatin modifiers and histone modifications in bone formation, regeneration, and therapeutic intervention for bone-related disease

“…Transgenic overexpression of Wdr5 using a 2.3-kb α (1)I-collagen promoter induced accelerated osteoblast and chondrocyte differentiation resulting in substantially increased endochondral bone growth suggesting [63]. Several other acetyltransferases have been implicated in epigenetic regulation of bone formation, osteoblast-related gene expression or deregulated in osteoarthritis including PCAF (KAT2B) [60, 64], MOZ/MORF (KAT6A/KAT6B) [65, 66], and the circadian-rhythm specific acetyltransferase: Clock (KAT13D) [67]. …”