Bone Research Laboratory, School of Physiology, Faculty of Health Sciences, Medical School, University of the Witwatersrand, Parktown, Johannesburg 2193 South Africa.
Department of Internal Medicine, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, South Africa.
Biomaterials. 2014 Mar;35(9):2773-88. doi: 10.1016/j.biomaterials.2013.12.062. Epub 2014 Jan 15.
Implantation of recombinant human transforming growth factor-β3 (hTGF-β3) with coral-derived calcium carbonate-based macroporous bioreactors with limited conversion to hydroxyapatite (7% HA/CC) in the rectus abdominis muscle of the non-human primate Chacma baboon Papio ursinus induces endochondral bone formation. The exact mechanisms by which hTGF-β3 signalling induces bone in heterotopic sites of P. ursinus are not known. Coral-derived 7% HA/CC bioreactors with and without 125 μg hTGF-β3 were implanted in triplicate in the rectus abdominis muscle of 6 adult baboons. 7% HA/CC bioreactors either with or without hTGF-β3 were loaded with 125 μg of recombinant human Noggin (hNoggin), a bone morphogenetic proteins (BMPs) antagonist. Tissues on day 15, 60 and 90 were analysed by histomorphometry and quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Down-regulation of BMP-2 characterized 7% HA/CC constructs preloaded with 125 μg hNoggin with Noggin down-regulated on day 60 and 90 together with lack of TGF-β3 expression. Down-regulation of BMP-2 correlated with minimal bone formation by induction. hTGF-β3/hNoggin pre-treated bioreactors up-regulated BMP-2 but only on day 90 together with a significant down-regulation of Noggin on day 60 and 90, correlating with the induction of bone formation, albeit limited, on day 90 at the periphery of the macroporous bioreactors only. hTGF-β3 treated bioreactors significantly down-regulated BMP-2 on day 15 whilst up-regulating BMP-2 on day 60 and 90, together with down-regulation of Noggin on day 60 and 90 correlating with the prominent induction of bone formation. hTGF-β3 significantly up-regulated RUNX-2 and Osteocalcin expression on day 15 controlling the differentiation of progenitor stem cells into the osteoblastic lineage. The induction of bone as initiated by hTGF-β3 in the rectus abdominis muscle of P. ursinus is via the BMPs pathway with hTGF-β3 controlling the induction of bone formation by regulating the expression of BMPs via Noggin expression. These results unequivocally demonstrate that hTGF-β3 elicits bone induction by up-regulation of endogenous BMP-2 and is blocked by hNoggin.
在中非狒狒巴氏亚种（Papio ursinus）的腹直肌中植入重组人转化生长因子-β3（hTGF-β3）与珊瑚衍生的碳酸钙基大孔生物反应器（7%HA/CC），可将其有限转化为羟基磷灰石（7%HA/CC），可诱导软骨内成骨。hTGF-β3 信号诱导 P. ursinus 异位骨形成的确切机制尚不清楚。在 6 只成年狒狒的腹直肌中，分别植入了 3 组含有和不含有 125μg hTGF-β3 的珊瑚衍生的 7%HA/CC 生物反应器。7%HA/CC 生物反应器要么含有，要么不含有 125μg 的重组人 Noggin（hNoggin），这是一种骨形态发生蛋白（BMPs）拮抗剂。在第 15、60 和 90 天，通过组织形态计量学和定量逆转录聚合酶链反应（qRT-PCR）分析组织。预先加载了 125μg hNoggin 的 7%HA/CC 构建体下调了 BMP-2 的表达，Noggin 在第 60 和 90 天下调，同时缺乏 TGF-β3 的表达。BMP-2 的下调与诱导的最小骨形成有关。hTGF-β3/hNoggin 预处理的生物反应器上调了 BMP-2，但仅在第 90 天上调，同时在第 60 和 90 天下调了 Noggin，这与第 90 天仅在大孔生物反应器外围诱导骨形成有关，尽管有限。hTGF-β3 处理的生物反应器在第 15 天显著下调了 BMP-2，而在第 60 和 90 天上调了 BMP-2，同时在第 60 和 90 天下调了 Noggin，这与诱导的骨形成有关。hTGF-β3 在第 15 天显著上调了 RUNX-2 和骨钙素的表达，控制祖细胞向成骨细胞系的分化。hTGF-β3 在 P. ursinus 的腹直肌中诱导的骨形成是通过 BMPs 途径进行的，hTGF-β3 通过 Noggin 的表达来调节 BMPs 的表达来控制骨形成的诱导。这些结果明确表明，hTGF-β3 通过上调内源性 BMP-2 引发骨诱导，并被 hNoggin 阻断。
