Identification of novel genes that promote persister formation by repressing transcription and cell division in Pseudomonas aeruginosa

2019 ◽  
Vol 74 (9) ◽  
pp. 2575-2587 ◽  
Author(s):  
Yuqing Long ◽  
Weixin Fu ◽  
Shouyi Li ◽  
Huan Ren ◽  
Mei Li ◽  
...  

AbstractObjectivesBacterial persisters are a small subpopulation of cells that are highly tolerant of antibiotics and contribute to chronic and recalcitrant infections. Global gene expression in Pseudomonas aeruginosa persister cells and genes contributing to persister formation remain largely unknown. The objective of this study was to examine the gene expression profiles of the persister cells and those that regained growth in fresh medium, as well as to identify novel genes related to persister formation.MethodsP. aeruginosa persister cells and those that regrew in fresh medium were collected and subjected to RNA sequencing analysis. Genes up-regulated in the persister cells were overexpressed to evaluate their roles in persister formation. The functions of the persister-contributing genes were assessed with pulse–chase assay, affinity chromatography, fluorescence and electron microscopy, as well as a light-scattering assay.ResultsAn operon containing PA2282–PA2287 was up-regulated in the persister cells and down-regulated in the regrowing cells. PA2285 and PA2287 play key roles in persister formation. PA2285 and PA2287 were found to bind to RpoC and FtsZ, which are involved in transcription and cell division, respectively. Pulse–chase assays demonstrated inhibitory effects of PA2285 and PA2287 on the overall transcription. Meanwhile, light-scattering and microscopy assays demonstrated that PA2285 and PA2287 interfere with cell division by inhibiting FtsZ aggregation. PA2285 and PA2287 are conserved in pseudomonads and their homologous genes in Pseudomonas putida contribute to persister formation.ConclusionsPA2285 and PA2287 are novel bifunctional proteins that contribute to persister formation in P. aeruginosa.

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Shuin Park ◽  
Sara Ranjbarvaziri ◽  
Fides Lay ◽  
Peng Zhao ◽  
Aldons J Lusis ◽  
...  

Fibroblasts are a heterogeneous population of cells that function within the injury response mechanisms across various tissues. Despite their importance in pathophysiology, the effects of different genetic backgrounds on fibroblast contribution to the development of disease has yet to be addressed. It has previously been shown that mice in the Hybrid Mouse Diversity Panel, which consists of 110 inbred mouse strains, display a spectrum in severity of cardiac fibrosis in response to chronic treatment of isoproterenol (ISO). Here, we characterized cardiac fibroblasts (CFbs) from three different mouse strains (C57BL/6J, C3H/HeJ, and KK/HIJ) which exhibited varying degrees of fibrosis after ISO treatment. The select strains of mice underwent sham or ISO treatment via intraperitoneally-implanted osmotic pumps for 21 days. Masson’s Trichrome staining showed significant differences in fibrosis in response to ISO, with KK/HIJ mice demonstrating the highest levels, C3H/HeJ exhibiting milder levels, and C57BL/6J demonstrating little to no fibrosis. When CFbs were isolated and cultured from each strain, the cells demonstrated similar traits at the basal level but responded to ISO stimuli in a strain-specific manner. Likewise, CFbs demonstrated differential behavior and gene expression in vivo in response to ISO. ISO treatment caused CFbs to proliferate similarly across all strains, however, immunofluorescence staining showed differential levels of CFb activation. Additionally, RNA-sequencing analysis revealed unique gene expression profiles of all three strains upon ISO treatment. Our study depicts the phenotypic heterogeneity of CFbs across different strains of mice and our results suggest that ISO-induced cardiac fibrosis is a complex process that is independent of fibroblast proliferation and is mainly driven by the activation/inhibition of genes involved in pro-fibrotic pathways.


Apmis ◽  
2011 ◽  
Vol 119 (4-5) ◽  
pp. 263-274 ◽  
Author(s):  
BAOLERI LEE ◽  
CHARLOTTE K. SCHJERLING ◽  
NIKOLAI KIRKBY ◽  
NADINE HOFFMANN ◽  
REHANNAH BORUP ◽  
...  

2008 ◽  
Vol 74 (18) ◽  
pp. 5784-5791 ◽  
Author(s):  
Tiffany L. Weir ◽  
Valerie J. Stull ◽  
Dayakar Badri ◽  
Lily A. Trunck ◽  
Herbert P. Schweizer ◽  
...  

ABSTRACT Although Pseudomonas aeruginosa is an opportunistic pathogen that does not often naturally infect alternate hosts, such as plants, the plant-P. aeruginosa model has become a widely recognized system for identifying new virulence determinants and studying the pathogenesis of the organism. Here, we examine how both host factors and P. aeruginosa PAO1 gene expression are affected in planta after infiltration into incompatible and compatible cultivars of tobacco (Nicotiana tabacum L.). N. tabacum has a resistance gene (N) against tobacco mosaic virus, and although resistance to PAO1 infection is correlated with the presence of a dominant N gene, our data suggest that it is not a factor in resistance against PAO1. We did observe that the resistant tobacco cultivar had higher basal levels of salicylic acid and a stronger salicylic acid response upon infiltration of PAO1. Salicylic acid acts as a signal to activate defense responses in plants, limiting the spread of the pathogen and preventing access to nutrients. It has also been shown to have direct virulence-modulating effects on P. aeruginosa. We also examined host effects on the pathogen by analyzing global gene expression profiles of bacteria removed from the intracellular fluid of the two plant hosts. We discovered that the availability of micronutrients, particularly sulfate and phosphates, is important for in planta pathogenesis and that the amounts of these nutrients made available to the bacteria may in turn have an effect on virulence gene expression. Indeed, there are several reports suggesting that P. aeruginosa virulence is influenced in mammalian hosts by the availability of micronutrients, such as iron and nitrogen, and by levels of O2.


2004 ◽  
Vol 72 (9) ◽  
pp. 5433-5438 ◽  
Author(s):  
Anders Frisk ◽  
Jill R. Schurr ◽  
Guoshun Wang ◽  
Donna C. Bertucci ◽  
Luis Marrero ◽  
...  

ABSTRACT The transcriptional profile of Pseudomonas aeruginosa after interactions with primary normal human airway epithelial cells was determined using Affymetrix GeneChip technology. Gene expression profiles indicated that various genes involved in phosphate acquisition and iron scavenging were differentially regulated.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Masahiro Asakawa ◽  
Michiko Itoh ◽  
Takayoshi Suganami ◽  
Takeru Sakai ◽  
Sayaka Kanai ◽  
...  

AbstractNon-alcoholic steatohepatitis (NASH), characterized by chronic inflammation and fibrosis, is predicted to be the leading cause of cirrhosis and hepatocellular carcinoma (HCC) in the next decade. Although recent evidence suggests the importance of fibrosis as the strongest determinant of HCC development, the molecular mechanisms underlying NASH-induced carcinogenesis still remain unclear. Here we performed RNA sequencing analysis to compare gene expression profiles of activated fibroblasts prepared from two distinct liver fibrosis models: carbon tetrachloride–induced fibrosis as a model without obesity and HCC and genetically obese melanocortin 4 receptor–deficient (MC4R-KO) mice fed Western diet, which develop steatosis, NASH, and eventually HCC. Our data showed that activated fibroblasts exhibited distinct gene expression patterns in each etiology, and that the ‘pathways in cancer’ were selectively upregulated in the activated fibroblasts from MC4R-KO mice. The most upregulated gene in these pathways was fibroblast growth factor 9 (FGF9), which was induced by metabolic stress such as palmitate. FGF9 exerted anti-apoptotic and pro-migratory effects in fibroblasts and hepatoma cells in vitro and accelerated tumor growth in a subcutaneous xenograft model. This study reveals upregulation of cancer-associated gene expression in activated fibroblasts in NASH, which would contribute to the progression from NASH to HCC.


2020 ◽  
Author(s):  
Surabhi Sonam ◽  
Sushant Bangru ◽  
Kimberly J. Perry ◽  
Auinash Kalsotra ◽  
Jonathan J. Henry

ABSTRACTCorneal Epithelial Stem Cells (CESCs) and their proliferative progeny, the Transit Amplifying Cells (TACs), are responsible for homeostasis and maintaining corneal transparency. Owing to our limited knowledge of cell fates and gene activity within the cornea, the search for unique markers to identify and isolate these cells remains crucial for ocular surface reconstruction. We performed single-cell RNA sequencing of corneal epithelial cells from stage 49-51 Xenopus larvae. We identified five main clusters with distinct molecular signatures, which represent apical, basal and keratocyte cell types as well as two discrete proliferative cell types in the bi-layered epithelium. Our data reveal several novel genes expressed in corneal cells and spatiotemporal changes in gene expression during corneal differentiation. Through gene regulatory network analysis, we identified key developmental gene regulons, which guide these different cell states. Our study offers a detailed atlas of single-cell transcriptomes in the frog corneal epithelium. In future, this work will be useful to elucidate the function of novel genes in corneal homeostasis, wound healing and cornea regeneration, which includes lens regeneration in Xenopus.SUMMARY STATEMENTThis study identifies cell types and transcriptional heterogeneity in the corneal epithelium that regulate its differentiation, and facilitates the search for corneal stem cell markers.


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