Article

NELL-1 binds to APR3 affecting human osteoblast proliferation and differentiation

Zhejiang California International NanoSystems Institute, Zhejiang University, Hangzhou, PR China.
FEBS letters (Impact Factor: 3.34). 06/2011; 585(15):2410-8. DOI: 10.1016/j.febslet.2011.06.024
Source: PubMed

ABSTRACT Nel-like protein 1 (NELL-1) is an osteoinductive molecule associated with premature calvarial suture closure. Here we identified apoptosis related protein 3 (APR3), a membrane protein known as a proliferation suppressor, as a binding protein of NELL-1 by biopanning. NELL-1 and APR3 colocalized on the nuclear envelope of human osteoblasts. NELL-1 significantly inhibited proliferation of osteoblasts co-transfected with APR3 through further down-regulation of Cyclin D1. The co-expression of NELL-1 and APR3 enhanced Ocn and Bsp expression and mineralization. RNAi of APR3 significantly reduced the differentiation effect of NELL-1. These findings suggest that the effects of NELL-1 on osteoblastic differentiation and proliferation are partly through binding to APR3.

0 Followers
 · 
127 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Osteoporosis is a skeletal disorder attributable to an imbalance in osteoblast and osteoclast activity. NELL-1, a secretory protein that promotes osteogenesis while suppressing osteoclastic activity, holds potential as an osteoporosis therapy. Recently, we demonstrated that PEGylation of NELL-1 significantly improves its thermostability while preserving its bioactivity in vitro. However, the effect of PEGylation on the pharmacokinetics and osteogenic potential of NELL-1 in vivo have yet to be investigated. The present study demonstrated that PEGylation of NELL-1 significantly increases the elimination half-life time of the protein from 5.5 h to 15.5 h while distributing more than 2-3 times the amount of protein to bone tissues (femur, tibia, vertebrae, calvaria) in vivo when compared to naked NELL-1. In addition, microCT and DXA analyses demonstrated that systemic NELL-PEG therapy administered every 4 or 7 days significantly increases not only femoral and lumbar BMD and percent bone volume, but also new bone formation throughout the overall skeleton after four weeks of treatment. Furthermore, immunohistochemistry revealed increased osteocalcin expression, while TRAP staining showed reduced osteoclast numbers in NELL-PEG groups. Our findings suggest that the PEGylation technique presents a viable and promising approach to further develop NELL-1 into an effective systemic therapeutic for the treatment of osteoporosis. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Biomaterials 07/2015; 57. DOI:10.1016/j.biomaterials.2015.03.063 · 8.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The apoptosis-related protein 3 (APR3) gene was first cloned from HL-60 cells treated with all-trans-retinoic acid and was thought to be related to tumor cell apoptosis or differentiation. In this study, we sought to investigate its expression profile in cervical squamous cell carcinoma (SCC) and preneoplastic lesions to determine whether APR3 is involved in the malignant progression of SCC. The purified partial recombinant APR3 proteins were used to immunize rabbits for raising antibodies, and the specificity of the polyclonal anti-APR3 antibody was determined by enzyme-linked immunosorbent assay and Western blot. Sections were assessed for APR3 expression by immunohistochemistry in archived tissues from human normal cervix samples (n = 20), cervical intraepithelial neoplasia (n = 19), and invasive SCC (n = 52). Specific cytoplasmic immunostaining was evaluated for overall intensity and uniformity to derive a combined histoscore. The results of enzyme-linked immunosorbent assay and Western blot indicated that anti-APR3 antibody can serve as a good tool for research. The immunohistochemical analysis demonstrated an increased expression of APR3 in SCC relative to normal cervix epithelium and cervical intraepithelial neoplasia (P < .05). Strikingly, APR3 expression level was significantly higher in nonkeratinizing SCCs compared with keratinizing SCCs (P < .05) and higher in carcinomas with lymph node metastasis compared with cases without lymph node metastasis (P < .05). This study demonstrates that APR3 expression is increased significantly with malignant progression of human cervical SCC, and thus, it may serve as a potential biomarker to predict prognosis of cervical SCC.
    Human pathology 10/2012; 44(3). DOI:10.1016/j.humpath.2012.05.028 · 2.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Canine osteosarcoma is clinically nearly identical to the human disease, but is common and highly heritable, making genetic dissection feasible. Through genome-wide association analyses in three breeds (greyhounds, Rottweilers, and Irish wolfhounds), we identify 33 inherited risk loci explaining 55% to 85% of phenotype variance in each breed. The greyhound locus exhibiting the strongest association, located 150 kilobases upstream of the genes CDKN2A/B, is also the most rearranged locus in canine osteosarcoma tumors. The top germline candidate variant is found at a >90% frequency in Rottweilers and Irish wolfhounds, and alters an evolutionarily constrained element that we show has strong enhancer activity in human osteosarcoma cells. In all three breeds, osteosarcoma-associated loci and regions of reduced heterozygosity are enriched for genes in pathways connected to bone differentiation and growth. Several pathways, including one of genes regulated by miR124, are also enriched for somatic copy-number changes in tumors. Mapping a complex cancer in multiple dog breeds reveals a polygenic spectrum of germline risk factors pointing to specific pathways as drivers of disease.
    Genome biology 12/2013; 14(12):R132. DOI:10.1186/gb-2013-14-12-r132 · 10.47 Impact Factor