Unfractionated Heparin Promotes Osteoclast Formation in Vitro by Inhibiting Osteoprotegerin Activity.
Heparin has been proven to enhance bone resorption and induce bone loss. Since osteoclasts play a pivotal role in bone resorption, the effect of heparin on osteoclastogenesis needs to be clarified. Since osteocytes are the key modulator during osteoclastogenesis, we evaluated heparin's effect on osteoclastogenesis in vitro by co-culturing an osteocyte cell line (MLO-Y4) and pre-osteoclasts (RAW264.7). In this co-culture system, heparin enhanced osteoclastogenesis and osteoclastic bone resorption while having no influence on the production of RANKL (receptor activator of NFκB ligand), M-CSF (macrophage colony-stimulating factor), and OPG (osteoprotegerin), which are three main regulatory factors derived from osteocytes. According to previous studies, heparin could bind specifically to OPG and inhibit its activity, so we hypothesized that this might be a possible mechanism of heparin activity. To test this hypothesis, osteoclastogenesis was induced using recombinant RANKL or MLO-Y4 supernatant. We found that heparin has no effect on RANKL-induced osteoclastogenesis (contains no OPG). However, after incubation with OPG, the capacity of MLO-Y4 supernatant for supporting osteoclast formation was increased. This effect disappeared after OPG was neutralized and reappeared after OPG was replenished. These results strongly suggest that heparin promotes osteocyte-modulated osteoclastogenesis in vitro, at least partially, through inhibiting OPG activity.
Renal Division, Peking University First Hospital, No. 8 Xishiku Street, Xi Cheng District, Beijing 100034, China. libinghanice@bjmu.edu.cn.|Peking University Institute of Nephrology, Beijing 100034, China. libinghanice@bjmu.edu.cn.|Key Laboratory of Renal Disease, Ministry of Health, Beijing 100034, China. libinghanice@bjmu.edu.cn.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China. libinghanice@bjmu.edu.cn.
Binghan
B
Li
Department of Cardiology, Peking University First Hospital, No. 8 Xishiku Street, Xi Cheng District, Beijing 100034, China. ludan39@foxmail.com.
Dan
D
Lu
Renal Division, Peking University First Hospital, No. 8 Xishiku Street, Xi Cheng District, Beijing 100034, China. chenyuqing112@hotmail.com.|Peking University Institute of Nephrology, Beijing 100034, China. chenyuqing112@hotmail.com.|Key Laboratory of Renal Disease, Ministry of Health, Beijing 100034, China. chenyuqing112@hotmail.com.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China. chenyuqing112@hotmail.com.
Yuqing
Y
Chen
Renal Division, Peking University First Hospital, No. 8 Xishiku Street, Xi Cheng District, Beijing 100034, China. mhzhao@bjmu.edu.cn.|Peking University Institute of Nephrology, Beijing 100034, China. mhzhao@bjmu.edu.cn.|Key Laboratory of Renal Disease, Ministry of Health, Beijing 100034, China. mhzhao@bjmu.edu.cn.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China. mhzhao@bjmu.edu.cn.
Minghui
M
Zhao
Renal Division, Peking University First Hospital, No. 8 Xishiku Street, Xi Cheng District, Beijing 100034, China. zuoli@bjmu.edu.cn.|Peking University Institute of Nephrology, Beijing 100034, China. zuoli@bjmu.edu.cn.|Key Laboratory of Renal Disease, Ministry of Health, Beijing 100034, China. zuoli@bjmu.edu.cn.|Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China. zuoli@bjmu.edu.cn.
Li
L
Zuo
D000818:Animals; D002460:Cell Line; D018920:Coculture Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D005343:Fibrinolytic Agents / Q000494:pharmacology; D006493:Heparin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D016173:Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000378:metabolism; D051379:Mice; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D053244:Osteoprotegerin / Q000032:analysis / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D053245:RANK Ligand / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D000067996:RAW 264.7 Cells; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000494:pharmacology
D005343:Fibrinolytic Agents; D053244:Osteoprotegerin; D053245:RANK Ligand; D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor; D006493:Heparin
osteoclast; osteoclastogenesis; osteocyte; osteoprotegerin (OPG); unfractionated heparin