PTH1 receptor is involved in mediating cellular response to long-chain polyunsaturated fatty acids.
PTH1 receptor is involved in mediating cellular response to long-chain polyunsaturated fatty acids.
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DOI：
10.1371/journal.pone.0052583
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Chachisvilis M
中科院分区：
文献类型：
--
作者：
Candelario J;Tavakoli H;Chachisvilis M
长链多不饱和脂肪酸（LCPUFA）影响骨骼健康的分子途径仍然难以捉摸。已知LCPUFA和甲状旁腺激素1型受体（PTH 1 R）都参与骨代谢，但两者之间的任何直接联系尚未建立。在这里，我们报告，LCPUFA能够直接，PTH 1 R依赖性激活细胞外配体调节激酶（ERK）。从广泛的脂肪酸研究，不同的链长，饱和度，和双键的位置，二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）引起最高的ERK磷酸化。此外，EPA以超激动方式增强甲状旁腺激素（PTH（1-34））的作用。EPA或DHA依赖性ERK磷酸化被PTH 1 R拮抗剂和PTH 1 R敲低抑制。抑制PTH 1 R下游信号分子蛋白激酶A（PKA）和C（PKC），减少EPA和DHA依赖性ERK磷酸化，表明脂肪酸主要激活G蛋白途径，而不是β-抑制蛋白途径。使用皮秒时间分辨荧光显微镜和基因工程PTH 1 R传感器（PTH-CC），我们检测到对EPA的构象反应类似于由PTH（1-34）引起的反应。PTH 1 R拮抗剂阻断EPA诱导的PTH-CC构象反应。利用荧光各向异性技术进行的竞争结合研究表明，EPA和DHA竞争性地结合并改变PTH 1受体对PTH（1-34）的亲和力，导致超激动反应。最后，我们发现，EPA刺激蛋白激酶B（Akt）磷酸化的PTH 1 R依赖的方式，并影响成骨细胞的生存途径，通过抑制糖皮质激素诱导的细胞死亡。我们的研究结果首次证明，LCPUFAs，EPA和DHA，可以激活PTH 1 R受体在纳摩尔浓度，从而提供了一个假定的分子机制的脂肪酸在骨骼中的作用。
The molecular pathways by which long chain polyunsaturated fatty acids (LCPUFA) influence skeletal health remain elusive. Both LCPUFA and parathyroid hormone type 1 receptor (PTH1R) are known to be involved in bone metabolism while any direct link between the two is yet to be established. Here we report that LCPUFA are capable of direct, PTH1R dependent activation of extracellular ligand-regulated kinases (ERK). From a wide range of fatty acids studied, varying in chain length, saturation, and position of double bonds, eicosapentaenoic (EPA) and docosahexaenoic fatty acids (DHA) caused the highest ERK phosphorylation. Moreover, EPA potentiated the effect of parathyroid hormone (PTH(1–34)) in a superagonistic manner. EPA or DHA dependent ERK phosphorylation was inhibited by the PTH1R antagonist and by knockdown of PTH1R. Inhibition of PTH1R downstream signaling molecules, protein kinases A (PKA) and C (PKC), reduced EPA and DHA dependent ERK phosphorylation indicating that fatty acids predominantly activate G-protein pathway and not the β-arrestin pathway. Using picosecond time-resolved fluorescence microscopy and a genetically engineered PTH1R sensor (PTH-CC), we detected conformational responses to EPA similar to those caused by PTH(1–34). PTH1R antagonist blocked the EPA induced conformational response of the PTH-CC. Competitive binding studies using fluorescence anisotropy technique showed that EPA and DHA competitively bind to and alter the affinity of PTH1 receptor to PTH(1–34) leading to a superagonistic response. Finally, we showed that EPA stimulates protein kinase B (Akt) phosphorylation in a PTH1R-dependent manner and affects the osteoblast survival pathway, by inhibiting glucocorticoid-induced cell death. Our findings demonstrate for the first time that LCPUFAs, EPA and DHA, can activate PTH1R receptor at nanomolar concentrations and consequently provide a putative molecular mechanism for the action of fatty acids in bone.