Tissue-nonspecific alkaline phosphatase is an anti-inflammatory nucleotidase
Tissue-nonspecific alkaline phosphatase is an anti-inflammatory nucleotidase
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DOI：
10.1016/j.bone.2020.115262
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发表时间：
2020-04-01
期刊：
影响因子：
4.1
通讯作者：
Magne, D.
中科院分区：
文献类型：
--
作者：
Bessueille, L.;Briolay, A.;Magne, D.
组织非特异性碱性磷酸酶（TNAP）通过其水解矿化抑制剂无机焦磷酸盐（PPi）的能力而对骨骼矿化是必需的，无机焦磷酸盐（PPi）主要通过外核苷酸焦磷酸酶磷酸二酯酶1（NPP 1）从细胞外ATP产生。由于患有TNAP缺乏症的儿童除了佝偻病之外还会发生骨干骺端自身炎症，因此我们假设TNAP也发挥抗炎作用，这依赖于促炎腺苷核苷酸水解为抗炎腺苷。我们在7日龄Alpl（+/-）小鼠（编码TNAP）的骨干骺端、矿化肥大软骨细胞和成骨细胞以及非矿化间充质干细胞（MSC）和中性粒细胞中探索了这一假设，这些细胞表达TNAP并存在于干骺端中，或可以在干骺端中招募。与Alpl（+/+）小鼠相比，7日龄Alpl（+/-）小鼠的骨干骺端具有显著增加的IL-1 β和IL-6水平以及降低的抗炎性IL-10细胞因子水平。在骨干骺端，小鼠肥大软骨细胞和成骨细胞，Alpl mRNA水平远高于那些的腺苷核苷酸酶Npp 1，Cd 39和Cd 73。在肥大软骨细胞中，用25 μ M MIS-0038949抑制TNAP可降低AMP和ATP的水解。然而，TNAP抑制并没有显着调节ATP和腺苷相关的影响，在这些细胞。我们观察到肥大软骨细胞中的部分TNAP蛋白从细胞膜被发送到基质囊泡，这可能解释了为什么TNAP参与ATP的水解，但没有显著调节其自分泌促炎作用。在MSC中，TNAP不参与ATP水解，也不参与炎症介质的分泌。相反，在中性粒细胞中，MLS-0038949的TNAP抑制显著加剧了ATP相关的活化和IL-1 β的分泌，并延长了细胞存活期。总的来说，这些结果表明，TNAP是一种在肥大软骨细胞和中性粒细胞的核苷酸酶，这种核苷酸酶的功能是与自分泌作用的炎症只在中性粒细胞。
Tissue-nonspecific alkaline phosphatase (TNAP) is necessary for skeletal mineralization by its ability to hydrolyze the mineralization inhibitor inorganic pyrophosphate (PPi), which is mainly generated from extra cellular ATP by ectonucleotide pyrophosphatase phosphodiesterase 1 (NPP1). Since children with TNAP deficiency develop bone metaphyseal auto-inflammations in addition to rickets, we hypothesized that TNAP also exerts anti-inflammatory effects relying on the hydrolysis of pro-inflammatory adenosine nucleotides into the anti-inflammatory adenosine. We explored this hypothesis in bone metaphyses of 7-day-old Alpl(+/-) mice (encoding TNAP), in mineralizing hypertrophic chondrocytes and osteoblasts, and non-mineralizing mesenchymal stem cells (MSCs) and neutrophils, which express TNAP and are present, or can be recruited in the metaphysis. Bone metaphyses of 7-day-old Alpl(+/-) mice had significantly increased levels of Il-1 beta and Il-6 and decreased levels of the anti-inflammatory Il-10 cytokine as compared with Alpl(+/+) mice. In bone metaphyses, murine hypertrophic chondrocytes and osteoblasts, Alpl mRNA levels were much higher than those of the adenosine nucleotidases Npp1, Cd39 and Cd73. In hypertrophic chondrocytes, inhibition of TNAP with 25 mu M of MIS-0038949 decreased the hydrolysis of AMP and ATP. However, TNAP inhibition did not significantly modulate ATP- and adenosine-associated effects in these cells. We observed that part of TNAP proteins in hypertrophic chondrocytes was sent from the cell membrane to matrix vesicles, which may explain why TNAP participated in the hydrolysis of ATP but did not significantly modulate its autocrine pro-inflammatory effects. In MSCs, TNAP did not participate in ATP hydrolysis nor in secretion of inflammatory mediators. In contrast, in neutrophils, TNAP inhibition with MLS-0038949 significantly exacerbated ATP-associated activation and secretion of IL-1 beta, and extended cell survival. Collectively, these results demonstrate that TNAP is a nucleotidase in both hypertrophic chondrocytes and neutrophils, and that this nucleotidase function is associated with autocrine effects on inflammation only in neutrophils.