TNF-α mediates p38 MAP kinase activation and negatively regulates bone formation at the injured growth plate in rats

被引:106
作者
Zhou, Fiona H.
Foster, Bruce K.
Zhou, Xin-Fu
Cowin, Allison J.
Xian, Cory J.
机构
[1] Womens & Childrens Hosp, Dept Orthopaed Surg, Adelaide, SA 5006, Australia
[2] Univ Adelaide, Womens & Childrens Hosp, Dept Pediat, Adelaide, SA 5006, Australia
[3] Flinders Univ S Australia, Dept Human Physiol, Adelaide, SA 5001, Australia
[4] Child Hlth Res Inst, Adelaide, SA 5006, Australia
关键词
TNF-alpha; p38 mitogen-activated protein kinase; growth plate injury; inflammatory response; bone bridge formation; osteoblast differentiation; cbfa1;
D O I
10.1359/JBMR.060410
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Introduction: TNF-alpha inhibits expression of osteoblast differentiation factor cbfa1 and osteoblast differentiation in vitro and yet TNF-a signaling is essential for bone fracture healing. Roles of TNF-a. in the bony repair of injured growth plate cartilage are unknown. Materials and Methods: Roles of TNF-alpha in the activation of p38 mitogen activated protein (MAP) kinase and the subsequent bony repair of the injured growth plate were examined in young rats receiving the TNF-a inhibitor ENBREL or saline control. Activation of p38 was determined by Western blot analysis and immunohistochemistry. Inflammatory cell counts on day 1, measurements of repair tissue proportions, and counting of proliferative mesenchymal cells on day 8 at growth plate injury site were carried out (n = 6). Expression of inflammatory cytokines TNF-alpha and IL-1 beta, fibrogenic growth factor (FGF)-2, cbfa1, and bone protein osteocalcin at the injured growth plate was assessed by quantitative RT-PCR. Effects of TNF-alpha signaling on proliferation, migration, and apoptosis of rat bone marrow mesenchymal cells (rBMMCs) and the regulatory roles of p38 in these processes were examined using recombinant rat TNF-alpha, ENBREL, and the p38 inhibitor SB239063 in cultured primary rBMMCs. Results: p38 activation was induced in the injured growth plate during the initial inflammatory response, and activated p38 was immunolocalized in inflammatory cells at the injury site and in the adjacent growth plate. In addition, activation of p38 was blocked in rats treated with TNF-alpha antagonist, suggesting a role of TNF-alpha in p38 activation. Whereas TNF-alpha inhibition did not alter inflammatory infiltrate and expression of TNF-alpha and IL-1 beta at the injured growth plate on day 1, it reduced mesenchymal infiltrate and cell proliferation and FGF-2 expression on day 8. Consistently, TNF-alpha increased proliferation and migration of rBMMCs in vitro, whereas p38 inhibition reduced rBMMC proliferation and migration. At the injured growth plate on day 8, TNF-alpha inhibition increased expression of cbfa1 and osteocalcin and increased trabecular bone formation at the injury site. There was a significant inverse correlation between TNF-alpha and cbfa1 expression levels, suggesting a negative relationship between TNF-alpha and cbfa1 in this in vivo model. Conclusions: These observations suggest that TNF-alpha activates p38 MAP kinase during the inflammatory response at the injured growth plate, and TNF-alpha-p38 signaling seems to be required for marrow mesenchymal cell proliferation and migration at the growth plate injury site and in cell culture. Furthermore, TNF signaling has an inhibitory effect on bone formation at the injured growth plate by suppressing bone cell differentiation and bone matrix synthesis at the injury site.
引用
收藏
页码:1075 / 1088
页数:14
相关论文
共 51 条
[1]   Tumor necrosis factor-α inhibits pre-osteoblast differentiation through its type-1 receptor [J].
Abbas, S ;
Zhang, YH ;
Clohisy, JC ;
Abu-Amer, Y .
CYTOKINE, 2003, 22 (1-2) :33-41
[2]   Induction of apoptosis in chondrocytes by tumor necrosis factor-alpha [J].
Aizawa, T ;
Kon, T ;
Einhorn, TA ;
Gerstenfeld, LC .
JOURNAL OF ORTHOPAEDIC RESEARCH, 2001, 19 (05) :785-796
[3]  
[Anonymous], 2006, FRACTURES CHILDREN, P21
[4]  
ARASAPAM G, 2006, IN PRESS J CELL BIOC
[5]   Differential effects of SB 242235, a selective p38 mitogen-activated protein kinase inhibitor, on IL-1 treated bovine and human cartilage/chondrocyte cultures [J].
Badger, AM ;
Roshak, AK ;
Cook, MN ;
Newman-Tarr, TM ;
Swift, BA ;
Carlson, K ;
Connor, JR ;
Lee, JC ;
Gowen, M ;
Lark, MW ;
Kumar, S .
OSTEOARTHRITIS AND CARTILAGE, 2000, 8 (06) :434-443
[6]  
Bakin AV, 2002, J CELL SCI, V115, P3193
[7]  
Barone FC, 2001, J PHARMACOL EXP THER, V296, P312
[8]   STIMULATION OF BONE-RESORPTION AND INHIBITION OF BONE-FORMATION INVITRO BY HUMAN-TUMOR NECROSIS FACTORS [J].
BERTOLINI, DR ;
NEDWIN, GE ;
BRINGMAN, TS ;
SMITH, DD ;
MUNDY, GR .
NATURE, 1986, 319 (6053) :516-518
[9]   One day exposure to FGF-2 was sufficient for the regenerative repair of full-thickness defects of articular cartilage in rabbits [J].
Chuma, H ;
Mizuta, H ;
Kudo, S ;
Takagi, K ;
Hiraki, Y .
OSTEOARTHRITIS AND CARTILAGE, 2004, 12 (10) :834-842
[10]   HOW MAP KINASES ARE REGULATED [J].
COBB, MH ;
GOLDSMITH, EJ .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1995, 270 (25) :14843-14846