The NAMPT Promoter Is Regulated by Mechanical Stress, Signal Transducer and Activator of Transcription 5, and Acute Respiratory Distress Syndrome-Associated Genetic Variants
The NAMPT Promoter Is Regulated by Mechanical Stress, Signal Transducer and Activator of Transcription 5, and Acute Respiratory Distress Syndrome-Associated Genetic Variants
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DOI：
10.1165/rcmb.2014-0117oc
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发表时间：
2014-11-01
影响因子：
6.4
通讯作者：
Garcia, Joe G. N.
中科院分区：
文献类型：
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作者：
Sun, Xiaoguang;Elangovan, Venkateswaran Ramamoorthi;Garcia, Joe G. N.
烟酰胺磷酸核糖基转移酶（NAMPT）转录的增加与呼吸机诱导的炎性肺损伤（VILI）在机制上相关，NAMPT生物利用度降低可减轻VILI的严重程度。NAMPT启动子调控过度机械应力的分子机制仍然知之甚少。本研究的目的是确定特定的转录因子，急性呼吸窘迫综合征（ARDS）相关的单核苷酸多态性（SNPs），和启动子去甲基化NAMPT转录调节的贡献，在机械应力。在体内NAMPT蛋白表达水平进行了检查，小鼠暴露于高潮气量机械通气。体外NAMPT表达水平在暴露于5或18%循环拉伸（CS）的人肺动脉内皮细胞中进行了检查，NAMPT启动子活性使用具有一系列嵌套缺失的NAMPT启动子荧光素酶报告基因构建体进行评估。体外NAMPT转录调控的进一步特点是测量荧光素酶活性，DNA去甲基化，染色质免疫沉淀。VILI攻击的小鼠表现出显着增加NAMPT表达支气管肺泡灌洗白细胞和肺内皮细胞。在NAMPT启动子中从22，428至22，128 bp鉴定出机械应力诱导区（MSIR）。该MSIR调节NAMPT启动子活性、mRNA表达以及信号转导子和转录激活子5（STAT 5）结合，其显著增加18% CS。此外，NAMPT启动子活性增加的药理学启动子去甲基化和抑制STAT5沉默。ARDS相关的NAMPT启动子SNP rs59744560（2948G/T）和rs7789066（22，422A/G）均以STAT5依赖性方式显著升高NAMPT启动子活性。我们的研究结果表明，NAMPT是一个关键的新的ARDS治疗靶点和候选基因与遗传/表观遗传转录调控响应过度的机械应力。
Increased nicotinamide phosphoribosyltransferase (NAMPT) transcription is mechanistically linked to ventilator-induced inflammatory lung injury (VILI), with VILI severity attenuated by reduced NAMPT bioavailability. The molecular mechanisms of NAMPT promoter regulation in response to excessive mechanical stress remain poorly understood. The objective of this study was to define the contribution of specific transcription factors, acute respiratory distress syndrome (ARDS)-associated single nucleotide polymorphisms (SNPs), and promoter demethylation to NAMPT transcriptional regulation in response to mechanical stress. In vivo NAMPT protein expression levels were examined in mice exposed to high tidal volume mechanical ventilation. In vitro NAMPT expression levels were examined in human pulmonary artery endothelial cells exposed to 5 or 18% cyclic stretch (CS), with NAMPT promoter activity assessed using NAMPT promoter luciferase reporter constructs with a series of nested deletions. In vitro NAMPT transcriptional regulation was further characterized by measuring luciferase activity, DNA demethylation, and chromatin immunoprecipitation. VILI-challenged mice exhibited significantly increased NAMPT expression in bronchoalveolar lavage leukocytes and in lung endothelium. A mechanical stress-inducible region (MSIR) was identified in the NAMPT promoter from 22,428 to 22,128 bp. This MSIR regulates NAMPT promoter activity, mRNA expression, and signal transducer and activator of transcription 5 (STAT5) binding, which is significantly increased by 18% CS. In addition, NAMPT promoter activity was increased by pharmacologic promoter demethylation and inhibited by STAT5 silencing. ARDS-associated NAMPT promoter SNPs rs59744560 (2948G/T) and rs7789066 (22,422A/G) each significantly elevated NAMPT promoter activity in response to 18% CS in a STAT5-dependent manner. Our results show that NAMPT is a key novel ARDS therapeutic target and candidate gene with genetic/epigenetic transcriptional regulation in response to excessive mechanical stress.