Mechanistic studies on the effects of nicotinamide on megakaryocytic polyploidization and the roles of NAD+ levels and SIRT inhibition.
Mechanistic studies on the effects of nicotinamide on megakaryocytic polyploidization and the roles of NAD+ levels and SIRT inhibition.
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DOI：
10.1016/j.exphem.2009.08.004
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发表时间：
2009-11
影响因子：
2.6
通讯作者：
Miller, William M.
中科院分区：
文献类型：
--
作者：
Giammona, Lisa M.;Panuganti, Swapna;Kemper, Jan M.;Apostolidis, Pani A.;Lindsey, Stephan;Papoutsakis, Eleftherios T.;Miller, William M.
巨核细胞(MKS)经历内丝分裂并成为多倍体。MK倍体与血小板生成相关。我们先前的研究表明，烟酰胺(NIC)能显著增加人外周血(MPB)CD34+细胞培养中的Mk倍体。本研究旨在探讨NIC效应的共性，NIC对MK超微结构的影响，以及倍性增加的可能机制。用电子显微镜观察Mk的超微结构，用流式细胞仪检测不同巨核细胞条件下NIC对MPB CD34+细胞Mk分化和倍性的影响。对NIC和其他NAD+前体细胞的MK倍体和NAD(H)含量进行评估。我们测试了SIRT1和SIRT2组蛋白/蛋白去乙酰基酶的其他抑制剂，并在NIC治疗后，评估了SIRT1/2靶标乙酰化的变化。NIC在不同培养条件下均可增加Mk的倍性，但不改变Mk的超微结构。6.25 mm网卡使NAD+级别增加了5倍。喹啉酸对NAD+的增加与1 mM Nic相似，但倍性增加幅度要小得多。NIC或SIRT1/2抑制剂Cambinol可使Mk倍体增加，而SIRT2抑制剂AGK2可适度增加Mk倍体。NIC处理的细胞中SIRT1/2的抑制表现为核小体和P53乙酰化的增加。P53与NIC的乙酰化程度越高，P53与其共同DNA结合序列的结合程度就越高。NIC在不改变Mk形态的情况下，在广泛的条件下极大地增加了Mk倍性。抑制SIRT1和/或SIRT2是NIC影响MK成熟的主要原因。
Megakaryocytic cells (Mks) undergo endomitosis and become polyploid. Mk ploidy correlates with platelet production. We previously showed that nicotinamide (NIC) greatly increases Mk ploidy in cultures of human mobilized peripheral blood (mPB) CD34+ cells. This study aims to examine the generality of NIC effects, NIC’s impact on Mk ultrastructure, and potential mechanisms for the increased ploidy. We used electron microscopy to examine Mk ultrastructure and flow cytometry to evaluate NIC effects on Mk differentiation and ploidy in mPB CD34+ cell cultures under diverse megakaryopoietic conditions. Mk ploidy and NAD(H) content were evaluated for NIC and other NAD+ precursors. We tested additional inhibitors of the SIRT1 and SIRT2 histone/protein deacetylases and, after treatment with NIC, evaluated changes in the acetylation of SIRT1/2 targets. NIC increased ploidy under diverse culture conditions and did not alter Mk ultrastructure. 6.25 mM NIC increased NAD+ levels 5-fold. Quinolinic acid increased NAD+ similar to that for 1 mM NIC, but yielded a much smaller ploidy increase. Similar increases in Mk ploidy were obtained using NIC or the SIRT1/2 inhibitor cambinol, while the SIRT2 inhibitor AGK2 moderately increased ploidy. SIRT1/2 inhibition in cells treated with NIC was evidenced by increased acetylation of nucleosomes and p53. Greater p53 acetylation with NIC was associated with increased binding of p53 to its consensus DNA binding sequence. NIC greatly increases Mk ploidy under a wide range of conditions without altering Mk morphology. Inhibition of SIRT1 and/or SIRT2 is primarily responsible for NIC effects on Mk maturation.
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影响因子：
2.6
作者：
Fuhrken, Peter G.;Chen, Chi;Papoutsakis, Eleftherios T.
通讯作者：
Papoutsakis, Eleftherios T.
影响因子：
45.3
作者：
Elting, LS;Rubenstein, EB;Benjamin, RS
通讯作者：
Benjamin, RS
影响因子：
16
作者：
Avalos, JL;Bever, KM;Wolberger, C
通讯作者：
Wolberger, C
影响因子：
2.9
作者：
BERNOFSKY, C;SWAN, M
通讯作者：
SWAN, M
DOI：
10.1073/pnas.261574398
发表时间：
2001-12-18
影响因子：
11.1
作者：
Bedalov, A;Gatbonton, T;Simon, JA
通讯作者：
Simon, JA