RRC ID 48530
著者 Okino N, Ito M.
タイトル Molecular mechanism for sphingosine-induced Pseudomonas ceramidase expression through the transcriptional regulator SphR.
ジャーナル Sci Rep
Abstract Pseudomonas aeruginosa, an opportunistic, but serious multidrug-resistant pathogen, secretes a ceramidase capable of cleaving the N-acyl linkage of ceramide to generate fatty acids and sphingosine. We previously reported that the secretion of P. aeruginosa ceramidase was induced by host-derived sphingolipids, through which phospholipase C-induced hemolysis was significantly enhanced. We herein investigated the gene(s) regulating sphingolipid-induced ceramidase expression and identified SphR, which encodes a putative AraC family transcriptional regulator. Disruption of the sphR gene in P. aeruginosa markedly decreased the sphingomyelin-induced secretion of ceramidase, reduced hemolytic activity, and resulted in the loss of sphingomyelin-induced ceramidase expression. A microarray analysis confirmed that sphingomyelin significantly induced ceramidase expression in P. aeruginosa. Furthermore, an electrophoretic mobility shift assay revealed that SphR specifically bound free sphingoid bases such as sphingosine, dihydrosphingosine, and phytosphingosine, but not sphingomyelin or ceramide. A β-galactosidase-assisted promoter assay showed that sphingosine activated ceramidase expression through SphR at a concentration of 100 nM. Collectively, these results demonstrated that sphingosine induces the secretion of ceramidase by promoting the mRNA expression of ceramidase through SphR, thereby enhancing hemolytic phospholipase C-induced cytotoxicity. These results facilitate understanding of the physiological role of bacterial ceramidase in host cells.
巻・号 6
ページ 38797
公開日 2016-12-12
DOI 10.1038/srep38797
PII srep38797
PMID 27941831
PMC PMC5150637
MeSH Bacterial Proteins / biosynthesis* Bacterial Proteins / genetics Base Sequence Ceramidases / biosynthesis* Ceramidases / genetics Ceramides / pharmacology Gene Deletion Gene Expression Regulation, Bacterial* / drug effects Genes, Bacterial Genes, araC Hemolysis Multigene Family Promoter Regions, Genetic Protein Array Analysis Pseudomonas aeruginosa / enzymology Pseudomonas aeruginosa / genetics* Pseudomonas aeruginosa / growth & development RNA, Bacterial / biosynthesis RNA, Bacterial / genetics RNA, Messenger / biosynthesis RNA, Messenger / genetics Recombinant Fusion Proteins / metabolism Sequence Alignment Sequence Homology, Nucleic Acid Sphingomyelins / metabolism Sphingosine / metabolism Sphingosine / pharmacology Substrate Specificity Transcription Factors / deficiency Transcription Factors / genetics Transcription Factors / physiology* Transcription, Genetic* / drug effects
IF 3.998
引用数 5
WOS 分野 BIOCHEMISTRY & MOLECULAR BIOLOGY
リソース情報
一般微生物 JCM 14847