title: The NAMPT promoter is regulated by mechanical stress, signal transducer and activator of transcription 5, and acute respiratory distress syndrome-associated genetic variants.
abstract: 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 -2,428 to -2,128 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 (-948G/T) and rs7789066 (-2,422A/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.
authors.affiliation: 1 Department of Medicine and.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Sun
authors.forename: Venkateswaran Ramamoorthi
authors.initials: VR
authors.lastname: Elangovan
authors.forename: Brandon
authors.initials: B
authors.lastname: Mapes
authors.forename: Sara M
authors.initials: SM
authors.lastname: Camp
authors.forename: Saad
authors.initials: S
authors.lastname: Sammani
authors.forename: Laleh
authors.initials: L
authors.lastname: Saadat
authors.forename: Ermelinda
authors.initials: E
authors.lastname: Ceco
authors.forename: Shwu-Fan
authors.initials: SF
authors.lastname: Ma
authors.forename: Carlos
authors.initials: C
authors.lastname: Flores
authors.forename: Matthew S
authors.initials: MS
authors.lastname: MacDougall
authors.forename: Hector
authors.initials: H
authors.lastname: Quijada
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Kempf
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.forename: Eddie T
authors.initials: ET
authors.lastname: Chiang
authors.forename: Joe G N
authors.initials: JG
authors.lastname: Garcia
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D055371:Acute Lung Injury / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics* / Q000502:physiology; D019175:DNA Methylation / Q000502:physiology; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D044127:Epigenesis, Genetic / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology; D014644:Genetic Variation / Q000235:genetics; D006801:Humans; D008297:Male; D008810:Mice, Inbred C57BL; D054409:Nicotinamide Phosphoribosyltransferase / Q000235:genetics* / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology; D011651:Pulmonary Artery / Q000166:cytology; D034741:RNA, Small Interfering / Q000235:genetics; D012121:Respiration, Artificial / Q000009:adverse effects; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000235:genetics* / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D013314:Stress, Mechanical; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D020121:5' Untranslated Regions; D016207:Cytokines; D034741:RNA, Small Interfering; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; C494093:Stat5a protein, mouse; D025521:Tumor Suppressor Proteins; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human; C495867:nicotinamide phosphoribosyltransferase, mouse
keywords: B cell colony-enhancing factor; acute respiratory distress syndrome; cyclic stretch; nicotinamide phosphoribosyltransferase; signal transducer and activator of transcription 5