Effect of the presence of cholesterol in the interfacial microenvironment on the modulation of the alkaline phosphatase activity during in vitro mineralization
Effect of the presence of cholesterol in the interfacial microenvironment on the modulation of the alkaline phosphatase activity during in vitro mineralization
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DOI：
10.1016/j.colsurfb.2017.04.051
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发表时间：
2017-07-01
影响因子：
5.8
通讯作者：
Ciancaglini, P.
中科院分区：
文献类型：
--
作者：
Favarin, B. Z.;Andrade, M. A. R.;Ciancaglini, P.
骨架的矿化始于细胞源性基质囊泡（MVs）；然后，矿物质传播到细胞外胶原基质。组织非特异性碱性磷酸酶（TNAP）降解无机焦磷酸盐（PPi），这是一种有效的矿化抑制剂，并从ATP中提供P-i（磷酸盐）来启动矿化。与质膜相比，mv富含胆固醇（Chol）（约32%）和TNAP，但Chol如何影响TNAP活性尚不清楚。我们在双棕榈酰磷脂酰胆碱（DPPC）或二油基磷脂酰胆碱（DOPC）与胆碱或其衍生物胆甾酮（Achol）和麦角甾醇（Ergo）的脂质体中重组了TNAP。脂质体中DPPC和36%的甾醇增加了TNAP对ATP的催化活性。Chol的存在也使矿物质的繁殖增加了3.4倍。DOPC蛋白脂质体中TNAP对ATP的催化效率比DPPC蛋白脂质体低4倍。与DPPC蛋白脂质体相比，DOPC蛋白脂质体也增加了2.8倍的生物矿化。在由DOPC和36% Chol组成的蛋白脂质体中，TNAP更有效地催化ATP的水解。同样的行为也出现在Achol和Ergo身上。脂质组织和甾醇结构影响表面张力（γ）、单分子层中TNAP的磷酸水解活性和双分子层中TNAP的催化效率。Lot相（Achol）的膜比Lo相（Chol和Ergo）的膜提供了更好的动力学参数。综上所述，在矿化过程中，蛋白脂质体的物理性质和脂质的横向组织对TNAP活性介导的矿物繁殖的控制至关重要。(C) 2017 Elsevier B.V.版权所有
Mineralization of the skeleton starts within cell-derived matrix vesicles (MVs); then, minerals propagate to the extracellular collagenous matrix. Tissue-nonspecific alkaline phosphatase (TNAP) degrades inorganic pyrophosphate (PPi), a potent inhibitor of mineralization, and contributes P-i (Phosphate) from ATP to initiate mineralization. Compared to the plasma membrane, MVs are rich in Cholesterol (Chol) (similar to 32%) and TNAP, but how Chol influences TNAP activity remains unclear. We have reconstituted TNAP in liposomes of dipalmitoylphosphatidylcholine (DPPC) or dioleoylphosphatidylcholine (DOPC) combined with Chol or its derivatives Cholestenone (Achol) and Ergosterol (Ergo). DPPC plus 36% sterols in liposome increased the catalytic activity of TNAP toward ATP. The presence of Chol also increased the propagation of minerals by 3.4-fold. The catalytic efficiency of TNAP toward ATP was fourfold lower in DOPC proteoliposomes as compared to DPPC proteoliposomes. DOPC proteoliposomes also increased biomineralization by 2.8-fold as compared to DPPC proteoliposomes. TNAP catalyzed the hydrolysis of ATP more efficiently in the case of the proteoliposome consisting of DOPC with 36% Chol. The same behavior emerged with Achol and Ergo. The organization of the lipid and the structure of the sterol influenced the surface tension (gamma), the TNAP phosphohydrolytic activity in the monolayer, and the TNAP catalytic efficiency in the bilayers. Membranes in the Lot phase (Achol) provided better kinetic parameters as compared to membranes in the Lo phase (Chol and Ergo). In conclusion, the physical properties and the lateral organization of lipids in proteoliposomes are crucial to control mineral propagation mediated by TNAP activity during mineralization. (C) 2017 Elsevier B.V. All rights reserved.