Dynamics of intracellular bacterial replication at the single cell level

Hélaine, Sophie; Thompson, Jessica A.; Watson, Kathryn G.; Mei, Linfeng; Boyle, Cliona; Holden, David W.

doi:10.1073/pnas.1000041107

Cited by 268 publications

(354 citation statements)

References 31 publications

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“…Another study showed that persistent bacteria are sequestered within macrophages in systemic tissues, where they do not replicate and seem to be in a dormant-like state. This supports the idea of macrophages as a reservoir for persistent bacteria (Helaine et al, 2010). Another study published recently, showed that S. Typhimurium preferentially associates with anti-inflammatory/M2 macrophages at later stages of infection in mice (Eisele et al, 2013).…”

Section: Persistence In Immune Cellssupporting

confidence: 62%

Molecular Mechanisms Used by Salmonella to Evade the Immune System

Bernal-Bayard¹,

Ramos‐Morales²

2018

Current Issues in Molecular Biology

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Section: Persistence In Immune Cellssupporting

confidence: 62%

Molecular Mechanisms Used by Salmonella to Evade the Immune System

Bernal-Bayard¹,

Ramos‐Morales²

2018

Current Issues in Molecular Biology

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“…Heterogeneity of intracellular bacterial population has already been reported for Salmonella. 35,51 Indeed, upon entry into macrophages, some Salmonella do not replicate and enter a dormant-like state. It is speculated that these living nonreplicating bacteria could represent a reservoir of persistent bacteria.…”

Section: Discussionmentioning

confidence: 99%

“…THP-1 monocytes were differentiated into macrophages by treatment with 20 ng/ml phorbol myristate acetate (PMA) for 18 h. Primary bone marrow-derived macrophages (BMDMs) were obtained from wild-type and TLR-4 knockout BALB/c mice, extracted from tibia and femur, and grown as previously described. 35 …”

Section: Cell Culturementioning

confidence: 99%

Intracellular colon cancer-associated Escherichia coli promote protumoral activities of human macrophages by inducing sustained COX-2 expression

Raisch

Rolhion

Dubois

et al. 2015

Laboratory Investigation

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Intestinal dysbiosis has been reported in patients with colorectal cancer, and there is a high prevalence of Escherichia coli belonging to B2 phylogroup and producing a genotoxin, termed colibactin. Macrophages are one of the predominant tumor-infiltrating immune cells supporting key processes in tumor progression by producing protumoral factors such as cyclooxygenase-2 (COX-2). Here, we investigated whether B2 E. coli colonizing colon tumors could influence protumoral activities of macrophages. In contrast to commensal or nonpathogenic E. coli strains that were efficiently and rapidly degraded by macrophages at 24 h after infection, colon cancer-associated E. coli were able to resist killing by human THP-1 macrophages, to replicate intracellularly, and to persist inside host cells until at least 72 h after infection. Significant increases in COX-2 expression were observed in macrophages infected with colon cancer E. coli compared with macrophages infected with commensal and nonpathogenic E. coli strains or uninfected cells at 72 h after infection. Induction of COX-2 expression required live bacteria and was not due to colibactin production, as similar COX-2 levels were observed in macrophages infected with the wild-type colon cancer-associated E. coli 11G5 strain or a clbQ mutant unable to produce colibactin. Treatment of macrophages with ofloxacin, an antibiotic with intracellular tropism, efficiently decreased the number of intracellular bacteria and suppressed bacteria-induced COX-2 expression. This study provides new insights into the understanding of how tumor-infiltrating bacteria could influence cancer progression through their interaction with immune cells. Manipulation of microbes associated with tumors could have a deep influence on the secretion of protumoral molecules by infiltrating macrophages. Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies worldwide, making it the fourth most common cause of cancer deaths throughout the world. 1 CRC is a heterogeneous disease, including at least three major forms: hereditary, sporadic, and colitis-associated CRC. A large body of evidence indicates that genetic mutations, epigenetic changes, chronic inflammation, diet, and lifestyle deeply affect CRC onset. 2,3 In addition to these factors, gut microbiota dysbiosis has been reported in CRC patients. [4][5][6][7][8][9] Recent pyrosequencing analysis of CRC-associated bacterial microbiota has revealed dysbiosis with, in particular, overrepresentation of Fusobacterium and Bacteroides. [10][11][12][13][14] In addition, our group and others have shown that colonic adenomas, carcinomas, and the mucosa of CRC patients are abnormally colonized by Escherichia coli belonging to the B2 phylogroup, with a high prevalence of E. coli producing a genotoxin, termed colibactin, encoded by the pks genomic island. [15][16][17][18][19][20] It has been recently demonstrated that cells that survive infection with colibactin-producing E. coli display hallmarks of cellular senescence accompanied with productio...

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“…From an ecological point of view, the quantitative study of nongrowing bacteria is highly relevant: ecosystems such as soil, sea water, and biofilms are dominated by nongrowing bacteria. Nongrowing bacteria have been recently linked to persistent infections, which represent a growing health issue (5-7), therefore an understanding of the physiology of these bacteria, both in vitro and in vivo (8) should have important clinical implications.…”

mentioning

confidence: 99%

Direct observation of single stationary-phase bacteria reveals a surprisingly long period of constant protein production activity

Gefen

Fridman

Ronin

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

186

155

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Exponentially growing bacteria are rarely found in the wild, as microorganisms tend to spend most of their lifetime at stationary phase. Despite this general prevalence of stationary-phase bacteria, they are as yet poorly characterized. Our goal was to quantitatively study this phase by direct observation of single bacteria as they enter into stationary phase and by monitoring their activity over several days during growth arrest. For this purpose, we devised an experimental procedure for starving single Escherichia coli bacteria in microfluidic devices and measured their activity by monitoring the production rate of fluorescent proteins. When amino acids were the sole carbon source, the production rate decreased by an order of magnitude upon entry into stationary phase. We found that, even while growth-arrested, bacteria continued to produce proteins at a surprisingly constant rate over several days. Our identification of this newly observed period of constant activity in nongrowing cells, designated as constant activity stationary phase, makes possible the conduction of assays that require constant protein expression over time, and are therefore difficult to perform under exponential growth conditions. Moreover, we show that exogenous protein expression bears no fitness cost on the regrowth of the population when starvation ends. Further characterization of constant activity stationary phase-a phase where nongrowing bacteria can be quantitatively studied over several days in a reproducible manner-should contribute to a better understanding of this ubiquitous but overlooked physiological state of bacteria in nature.bacterial metabolism | constant activity stationary phase | CASP I n his thesis, Jacques Monod (1) pioneered the precise and quantitative analysis of bacterial cultures. He focused on mathematically defining and measuring the growth rate of exponentially growing bacterial populations. In parallel to Leo Szilard and coworker (2), he developed the chemostat (3), which allows the maintenance of constant growth conditions in bacterial cultures over time. These conceptual and experimental tools laid the foundation for quantitative studies of growing bacteria, which could be compared and reproduced. In contrast to these advances in the characterization of growing bacteria, the stationary phase, which is the prevalent state of bacteria in nature, is far from being characterized in a similarly satisfactory manner (4). From an ecological point of view, the quantitative study of nongrowing bacteria is highly relevant: ecosystems such as soil, sea water, and biofilms are dominated by nongrowing bacteria. Nongrowing bacteria have been recently linked to persistent infections, which represent a growing health issue (5-7), therefore an understanding of the physiology of these bacteria, both in vitro and in vivo (8) should have important clinical implications.Typically, stationary phase is attained when a culture exhausts nutrients and its OD remains constant. Starved microorganisms need to respond to a wide range ...

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Dynamics of intracellular bacterial replication at the single cell level

Cited by 268 publications

References 31 publications

Molecular Mechanisms Used by Salmonella to Evade the Immune System

Molecular Mechanisms Used by Salmonella to Evade the Immune System

Intracellular colon cancer-associated Escherichia coli promote protumoral activities of human macrophages by inducing sustained COX-2 expression

Direct observation of single stationary-phase bacteria reveals a surprisingly long period of constant protein production activity

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