The Cost of Virulence: Retarded Growth of Typhimurium Cells Expressing Type III Secretion System 1
Virulence factors generally enhance a pathogen's fitness and thereby foster transmission. However, most studies of pathogen fitness have been performed by averaging the phenotypes over large populations. Here, we have analyzed the fitness costs of virulence factor expression by Salmonella enterica subspecies I serovar Typhimurium in simple culture experiments. The type III secretion system ttss-1, a cardinal virulence factor for eliciting Salmonella diarrhea, is expressed by just a fraction of the S. Typhimurium population, yielding a mixture of cells that either express ttss-1 (TTSS-1+ phenotype) or not (TTSS-1− phenotype). Here, we studied in vitro the TTSS-1+ phenotype at the single cell level using fluorescent protein reporters. The regulator hilA controlled the fraction of TTSS-1+ individuals and their ttss-1 expression level. Strikingly, cells of the TTSS-1+ phenotype grew slower than cells of the TTSS-1− phenotype. The growth retardation was at least partially attributable to the expression of TTSS-1 effector and/or translocon proteins. In spite of this growth penalty, the TTSS-1+ subpopulation increased from <10% to approx. 60% during the late logarithmic growth phase of an LB batch culture. This was attributable to an increasing initiation rate of ttss-1 expression, in response to environmental cues accumulating during this growth phase, as shown by experimental data and mathematical modeling. Finally, hilA and hilD mutants, which form only fast-growing TTSS-1− cells, outcompeted wild type S. Typhimurium in mixed cultures. Our data demonstrated that virulence factor expression imposes a growth penalty in a non-host environment. This raises important questions about compensating mechanisms during host infection which ensure successful propagation of the genotype.
Vyšlo v časopise:
The Cost of Virulence: Retarded Growth of Typhimurium Cells Expressing Type III Secretion System 1. PLoS Pathog 7(7): e32767. doi:10.1371/journal.ppat.1002143
Kategorie:
Research Article
prolekare.web.journal.doi_sk:
https://doi.org/10.1371/journal.ppat.1002143
Souhrn
Virulence factors generally enhance a pathogen's fitness and thereby foster transmission. However, most studies of pathogen fitness have been performed by averaging the phenotypes over large populations. Here, we have analyzed the fitness costs of virulence factor expression by Salmonella enterica subspecies I serovar Typhimurium in simple culture experiments. The type III secretion system ttss-1, a cardinal virulence factor for eliciting Salmonella diarrhea, is expressed by just a fraction of the S. Typhimurium population, yielding a mixture of cells that either express ttss-1 (TTSS-1+ phenotype) or not (TTSS-1− phenotype). Here, we studied in vitro the TTSS-1+ phenotype at the single cell level using fluorescent protein reporters. The regulator hilA controlled the fraction of TTSS-1+ individuals and their ttss-1 expression level. Strikingly, cells of the TTSS-1+ phenotype grew slower than cells of the TTSS-1− phenotype. The growth retardation was at least partially attributable to the expression of TTSS-1 effector and/or translocon proteins. In spite of this growth penalty, the TTSS-1+ subpopulation increased from <10% to approx. 60% during the late logarithmic growth phase of an LB batch culture. This was attributable to an increasing initiation rate of ttss-1 expression, in response to environmental cues accumulating during this growth phase, as shown by experimental data and mathematical modeling. Finally, hilA and hilD mutants, which form only fast-growing TTSS-1− cells, outcompeted wild type S. Typhimurium in mixed cultures. Our data demonstrated that virulence factor expression imposes a growth penalty in a non-host environment. This raises important questions about compensating mechanisms during host infection which ensure successful propagation of the genotype.
Zdroje
1. HautefortIProencaMJHintonJC 2003 Single-copy green fluorescent protein gene fusions allow accurate measurement of Salmonella gene expression in vitro and during infection of mammalian cells. Appl Environ Microbiol 69 7480 7491
2. SchlumbergerMCMullerAJEhrbarKWinnenBDussI 2005 Real-time imaging of type III secretion: Salmonella SipA injection into host cells. Proc Natl Acad Sci U S A 102 12548 12553
3. WinnenBSchlumbergerMCSturmASchupbachKSiebenmannS 2008 Hierarchical effector protein transport by the Salmonella Typhimurium SPI-1 type III secretion system. PLoS ONE 3 e2178
4. AckermannMStecherBFreedNESonghetPHardtWD 2008 Self-destructive cooperation mediated by phenotypic noise. Nature 454 987 990
5. SainiSEllermeierJRSlauchJMRaoCV 2010 The role of coupled positive feedback in the expression of the SPI1 type three secretion system in Salmonella. PLoS Pathog 6 e1001025
6. SmitsWKKuipersOPVeeningJW 2006 Phenotypic variation in bacteria: the role of feedback regulation. Nat Rev Microbiol 4 259 271
7. LimSYunJYoonHParkCKimB 2007 Mlc regulation of Salmonella pathogenicity island I gene expression via hilE repression. Nucleic Acids Res 35 1822 1832
8. ElowitzMBLevineAJSiggiaEDSwainPS 2002 Stochastic gene expression in a single cell. Science 297 1183 1186
9. RosenfeldNYoungJWAlonUSwainPSElowitzMB 2005 Gene regulation at the single-cell level. Science 307 1962 1965
10. RajAvan OudenaardenA 2008 Nature, nurture, or chance: stochastic gene expression and its consequences. Cell 135 216 226
11. RaserJMO'SheaEK 2005 Noise in gene expression: origins, consequences, and control. Science 309 2010 2013
12. KussellEKishonyRBalabanNQLeiblerS 2005 Bacterial persistence: a model of survival in changing environments. Genetics 169 1807 1814
13. SchlumbergerMCHardtWD 2006 Salmonella type III secretion effectors: pulling the host cell's strings. Curr Opin Microbiol 9 46 54
14. WatsonPRGalyovEEPaulinSMJonesPWWallisTS 1998 Mutation of invH, but not stn, reduces Salmonella-induced enteritis in cattle. Infect Immun 66 1432 1438
15. TsolisRMAdamsLGFichtTABaumlerAJ 1999 Contribution of Salmonella typhimurium virulence factors to diarrheal disease in calves. Infect Immun 67 4879 4885
16. BarthelMHapfelmeierSQuintanilla-MartinezLKremerMRohdeM 2003 Pretreatment of mice with streptomycin provides a Salmonella enterica serovar Typhimurium colitis model that allows analysis of both pathogen and host. Infect Immun 71 2839 2858
17. WallisTSGalyovEE 2000 Molecular basis of Salmonella-induced enteritis. Mol Microbiol 36 997 1005
18. HapfelmeierSHardtWD 2005 A mouse model for S. typhimurium-induced enterocolitis. Trends Microbiol 13 497 503
19. SantosRLRaffatelluMBevinsCLAdamsLGTukelC 2009 Life in the inflamed intestine, Salmonella style. Trends Microbiol 17 498 506
20. SchechterLMDamrauerSMLeeCA 1999 Two AraC/XylS family members can independently counteract the effect of repressing sequences upstream of the hilA promoter. Mol Microbiol 32 629 642
21. BajajVHwangCLeeCA 1995 hilA is a novel ompR/toxR family member that activates the expression of Salmonella typhimurium invasion genes. Mol Microbiol 18 715 727
22. EllermeierJRSlauchJM 2007 Adaptation to the host environment: regulation of the SPI1 type III secretion system in Salmonella enterica serovar Typhimurium. Curr Opin Microbiol 10 24 29
23. StecherBRobbianiRWalkerAWWestendorfAMBarthelM 2007 Salmonella enterica serovar typhimurium exploits inflammation to compete with the intestinal microbiota. PLoS Biol 5 2177 2189
24. RaffatelluMGeorgeMDAkiyamaYHornsbyMJNuccioSP 2009 Lipocalin-2 resistance confers an advantage to Salmonella enterica serotype Typhimurium for growth and survival in the inflamed intestine. Cell Host Microbe 5 476 486
25. LuppCRobertsonMLWickhamMESekirovIChampionOL 2007 Host-mediated inflammation disrupts the intestinal microbiota and promotes the overgrowth of Enterobacteriaceae. Cell Host Microbe 2 204
26. StecherBBarthelMSchlumbergerMCHaberliLRabschW 2008 Motility allows S. Typhimurium to benefit from the mucosal defence. Cell Microbiol 10 1166 1180
27. StecherBHardtWD 2008 The role of microbiota in infectious disease. Trends Microbiol 16 107 114
28. LawleyTDBouleyDMHoyYEGerkeCRelmanDA 2008 Host transmission of Salmonella enterica serovar Typhimurium is controlled by virulence factors and indigenous intestinal microbiota. Infect Immun 76 403 416
29. WinterSEKeestraAMTsolisRMBaumlerAJ 2010 The blessings and curses of intestinal inflammation. Cell Host Microbe 8 36 43
30. YuJXiaoJRenXLaoKXieXS 2006 Probing gene expression in live cells, one protein molecule at a time. Science 311 1600 1603
31. WendlandMBumannD 2002 Optimization of GFP levels for analyzing Salmonella gene expression during an infection. FEBS Lett 521 105 108
32. TemmeKSalisHTullman-ErcekDLevskayaAHongSH 2008 Induction and relaxation dynamics of the regulatory network controlling the type III secretion system encoded within Salmonella pathogenicity island 1. J Mol Biol 377 47 61
33. Bailly-BechetMBeneckeAHardtWDLanzaVSturmA 2010 An externally modulated, noise-driven switch for the regulation of SPI1 in Salmonella enterica serovar Typhimurium. J Math Biol [Epub ahead of print]
34. BrunoJCJrFreitagNE 2010 Constitutive activation of PrfA tilts the balance of Listeria monocytogenes fitness towards life within the host versus environmental survival. PLoS One 5 e15138
35. TeplitskiMGoodierRIAhmerBM 2006 Catabolite repression of the SirA regulatory cascade in Salmonella enterica. Int J Med Microbiol 296 449 466
36. EllermeierJRSlauchJM 2008 Fur regulates expression of the Salmonella pathogenicity island 1 type III secretion system through HilD. J Bacteriol 190 476 486
37. NavarreWWPorwollikSWangYMcClellandMRosenH 2006 Selective silencing of foreign DNA with low GC content by the H-NS protein in Salmonella. Science 313 236 238
38. OlekhnovichINKadnerRJ 2007 Role of nucleoid-associated proteins Hha and H-NS in expression of Salmonella enterica activators HilD, HilC, and RtsA required for cell invasion. J Bacteriol 189 6882 6890
39. RietschAMekalanosJJ 2006 Metabolic regulation of type III secretion gene expression in Pseudomonas aeruginosa. Mol Microbiol 59 807 820
40. BrubakerRRSurgallaMJ 1964 The Effect of Ca++ and Mg++ on Lysis, Growth, and Production of Virulence Antigens by Pasteurella Pestis. J Infect Dis 114 13 25
41. HiguchiKKupferbergLLSmithJL 1959 Studies on the nutrition and physiology of Pasteurella pestis. III. Effects of calcium ions on the growth of virulent and avirulent strains of Pasteurella pestis. J Bacteriol 77 317 321
42. WileyDJRosqvistRSchesserK 2007 Induction of the Yersinia type 3 secretion system as an all-or-none phenomenon. J Mol Biol 373 27 37
43. MarteynBWestNPBrowningDFColeJAShawJG 2010 Modulation of Shigella virulence in response to available oxygen in vivo. Nature 465 355 358
44. SchiemannDAShopeSR 1991 Anaerobic growth of Salmonella typhimurium results in increased uptake by Henle 407 epithelial and mouse peritoneal cells in vitro and repression of a major outer membrane protein. Infect Immun 59 437 440
45. LostrohCPLeeCA 2001 The Salmonella pathogenicity island-1 type III secretion system. Microbes Infect 3 1281 1291
46. HuangYSuyemotoMGarnerCDCicconiKMAltierC 2008 Formate acts as a diffusible signal to induce Salmonella invasion. J Bacteriol 190 4233 4241
47. LeeCAFalkowS 1990 The ability of Salmonella to enter mammalian cells is affected by bacterial growth state. Proc Natl Acad Sci U S A 87 4304 4308
48. ErnstRKDombroskiDMMerrickJM 1990 Anaerobiosis, type 1 fimbriae, and growth phase are factors that affect invasion of HEp-2 cells by Salmonella typhimurium. Infect Immun 58 2014 2016
49. LeeCAJonesBDFalkowS 1992 Identification of a Salmonella typhimurium invasion locus by selection for hyperinvasive mutants. Proc Natl Acad Sci U S A 89 1847 1851
50. LawhonSDMaurerRSuyemotoMAltierC 2002 Intestinal short-chain fatty acids alter Salmonella typhimurium invasion gene expression and virulence through BarA/SirA. Mol Microbiol 46 1451 1464
51. GalanJECurtissR3rd 1990 Expression of Salmonella typhimurium genes required for invasion is regulated by changes in DNA supercoiling. Infect Immun 58 1879 1885
52. HuQCoburnBDengWLiYShiX 2008 Salmonella enterica serovar Senftenberg human clinical isolates lacking SPI-1. J Clin Microbiol 46 1330 1336
53. RahnKDe GrandisSAClarkeRCMcEwenSAGalanJE 1992 Amplification of an invA gene sequence of Salmonella typhimurium by polymerase chain reaction as a specific method of detection of Salmonella. Mol Cell Probes 6 271 279
54. DatsenkoKAWannerBL 2000 One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc Natl Acad Sci U S A 97 6640 6645
55. HoffmannCGalleMDillingSKappeliRMullerAJ 2010 In macrophages, caspase-1 activation by SopE and the type III secretion system-1 of S. typhimurium can proceed in the absence of flagellin. PLoS One 5 e12477
56. EhrbarKHapfelmeierSStecherBHardtWD 2004 InvB is required for type III-dependent secretion of SopA in Salmonella enterica serovar Typhimurium. J Bacteriol 186 1215 1219
57. EhrbarKFriebelAMillerSIHardtWD 2003 Role of the Salmonella pathogenicity island 1 (SPI-1) protein InvB in type III secretion of SopE and SopE2, two Salmonella effector proteins encoded outside of SPI-1. J Bacteriol 185 6950 6967
58. Team RDC 2009 R: A language and environment for statistical computing. R Foundation for Statistical Computing
59. EllermeierCDEllermeierJRSlauchJM 2005 HilD, HilC and RtsA constitute a feed forward loop that controls expression of the SPI1 type three secretion system regulator hilA in Salmonella enterica serovar Typhimurium. Mol Microbiol 57 691 705
60. SchechterLMJainSAkbarSLeeCA 2003 The small nucleoid-binding proteins H-NS, HU, and Fis affect hilA expression in Salmonella enterica serovar Typhimurium. Infect Immun 71 5432 5435
61. HumphreysSRowleyGStevensonAAnjumMFWoodwardMJ 2004 Role of the two-component regulator CpxAR in the virulence of Salmonella enterica serotype Typhimurium. Infect Immun 72 4654 4661
62. AltierCSuyemotoMLawhonSD 2000 Regulation of Salmonella enterica serovar typhimurium invasion genes by csrA. Infect Immun 68 6790 6797
63. IlgKEndtKMisselwitzBStecherBAebiM 2009 O-antigen-negative Salmonella enterica serovar Typhimurium is attenuated in intestinal colonization but elicits colitis in streptomycin-treated mice. Infect Immun 77 2568 2575
64. BonifieldHRHughesKT 2003 Flagellar phase variation in Salmonella enterica is mediated by a posttranscriptional control mechanism. J Bacteriol 185 3567 3574
65. FreedNESilanderOKStecherBBohmAHardtWD 2008 A simple screen to identify promoters conferring high levels of phenotypic noise. PLoS Genet 4 e1000307
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Hygiena a epidemiológia Infekčné lekárstvo LaboratóriumČlánok vyšiel v časopise
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