Genes localized at Salmonella pathogenicity island-1 (SPI-1) are involved in Salmonella enterica invasion of host non-professional phagocytes. Interestingly, in macrophages, SPI-1-encoded proteins, in addition to invasion, induce cell death via activation of caspase-1 which also cleaves proIL-1β and proIL-18, precursors of 2 proinflammatory cytokines. In this study we were therefore interested in whether SPI-1-encoded type III secretion system (T3SS) may influence proinflammatory response of macrophages. To test this hypothesis, we infected primary porcine alveolar macrophages with wild-type S. Typhimurium and S. Enteritidis and their isogenic SPI-1 deletion mutants. ΔSPI1 mutants of both serovars invaded approx. 5 times less efficiently than the wild-type strains and despite this, macrophages responded to the infection with ΔSPI1 mutants by increased expression of proinflammatory cytokines IL-1β, IL-8, TNFα, IL-23α and GM-CSF. Identical macrophage responses to that induced by the ΔSPI1 mutants were also observed to the infection with sipB but not the sipA mutant. The hilA mutant exhibited an intermediate phenotype between the ΔSPI1 mutant and the wild-type S. Enteritidis. Our results showed that the SPI-1-encoded T3SS is required not only for cell invasion but in macrophages also for the suppression of early proinflammatory cytokine expression.

Veterinary Research Institute Brno Czech Republic

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Cirillo DM, Valdivia RH, Monack DM, Falkow S. Macrophage-dependent induction of the Salmonella pathogenicity island 2 type III secretion system and its role in intracellular survival. Mol Microbiol. 1998;30:175–188. doi: 10.1046/j.1365-2958.1998.01048.x. PubMed DOI

Murray RA, Lee CA. Invasion genes are not required for Salmonella enterica serovar typhimurium to breach the intestinal epithelium: evidence that salmonella pathogenicity island 1 has alternative functions during infection. Infect Immun. 2000;68:5050–5055. doi: 10.1128/IAI.68.9.5050-5055.2000. PubMed DOI PMC

Boyen F, Pasmans F, Van Immerseel F, Morgan E, Adriaensen C, Hernalsteens JP, Decostere A, Ducatelle R, Haesebrouck F. Salmonella Typhimurium SPI-1 genes promote intestinal but not tonsillar colonization in pigs. Microbes Infect. 2006;8:2899–2907. doi: 10.1016/j.micinf.2006.09.008. PubMed DOI

Karasova D, Sebkova A, Havlickova H, Sisak F, Volf J, Faldyna M, Ondrackova P, Kummer V, Rychlik I. Influence of 5 major Salmonella pathogenicity islands on NK cell depletion in mice infected with Salmonella enterica serovar Enteritidis. BMC Microbiol. 2010;10:75. doi: 10.1186/1471-2180-10-75. PubMed DOI PMC

Rychlik I, Karasova D, Sebkova A, Volf J, Sisak F, Havlickova H, Kummer V, Imre A, Szmolka A, Nagy B. Virulence potential of five major pathogenicity islands (SPI-1 to SPI-5) of Salmonella enterica serovar Enteritidis for chickens. BMC Microbiol. 2009;9:268. doi: 10.1186/1471-2180-9-268. PubMed DOI PMC

Hersh D, Monack DM, Smith MR, Ghori N, Falkow S, Zychlinsky A. The Salmonella invasin SipB induces macrophage apoptosis by binding to caspase-1. Proc Natl Acad Sci USA. 1999;96:2396–2401. doi: 10.1073/pnas.96.5.2396. PubMed DOI PMC

Lundberg U, Vinatzer U, Berdnik D, von Gabain A, Baccarini M. Growth phase-regulated induction of Salmonella-induced macrophage apoptosis correlates with transient expression of SPI-1 genes. J Bacteriol. 1999;181:3433–3437. PubMed PMC

Monack DM, Navarre WW, Falkow S. Salmonella-induced macrophage death: the role of caspase-1 in death and inflammation. Microbes Infect. 2001;3:1201–1212. doi: 10.1016/S1286-4579(01)01480-0. PubMed DOI

Monack DM, Hersh D, Ghori N, Bouley D, Zychlinsky A, Falkow S. Salmonella exploits caspase-1 to colonize Peyer's patches in a murine typhoid model. J Exp Med. 2000;192:249–258. doi: 10.1084/jem.192.2.249. PubMed DOI PMC

Methner U, Barrow PA, Gregorova D, Rychlik I. Intestinal colonisation-inhibition and virulence of Salmonella phoP, rpoS and ompC deletion mutants in chickens. Vet Microbiol. 2004;98:37–43. doi: 10.1016/j.vetmic.2003.10.019. PubMed DOI

Karasova D, Sebkova A, Vrbas V, Havlickova H, Sisak F, Rychlik I. Comparative analysis of Salmonella enterica serovar Enteritidis mutants with a vaccine potential. Vaccine. 2009;27:5265–5270. doi: 10.1016/j.vaccine.2009.06.060. PubMed DOI

Zelnickova P, Matiasovic J, Pavlova B, Kudlackova H, Kovaru F, Faldyna M. Quantitative nitric oxide production by rat, bovine and porcine macrophages. Nitric Oxide. 2008;19:36–41. doi: 10.1016/j.niox.2008.04.001. PubMed DOI

Volf J, Boyen F, Faldyna M, Pavlova B, Navratilova J, Rychlik I. Cytokine response of porcine cell lines to Salmonella enterica serovar typhimurium and its hilA and ssrA mutants. Zoonoses Public Health. 2007;54:286–293. doi: 10.1111/j.1863-2378.2007.01064.x. PubMed DOI

von der HK, Kandler MA, Fink L, Schoof E, Dotsch J, Brandenstein O, Bohle RM, Rascher W. High frequency oscillatory ventilation suppresses inflammatory response in lung tissue and microdissected alveolar macrophages in surfactant depleted piglets. Pediatr Res. 2004;55:339–346. doi: 10.1203/01.PDR.0000106802.55721.8A. PubMed DOI

Boyen F, Pasmans F, Donne E, Van Immerseel F, Adriaensen C, Hernalsteens JP, Ducatelle R, Haesebrouck F. Role of SPI-1 in the interactions of Salmonella Typhimurium with porcine macrophages. Vet Microbiol. 2006;113:35–44. doi: 10.1016/j.vetmic.2005.10.018. PubMed DOI

Kaniga K, Trollinger D, Galan JE. Identification of two targets of the type III protein secretion system encoded by the inv and spa loci of Salmonella typhimurium that have homology to the Shigella IpaD and IpaA proteins. J Bacteriol. 1995;177:7078–7085. PubMed PMC

Monack DM, Raupach B, Hromockyj AE, Falkow S. Salmonella typhimurium invasion induces apoptosis in infected macrophages. Proc Natl Acad Sci USA. 1996;93:9833–9838. doi: 10.1073/pnas.93.18.9833. PubMed DOI PMC

Forsberg M, Blomgran R, Lerm M, Sarndahl E, Sebti SM, Hamilton A, Stendahl O, Zheng L. Differential effects of invasion by and phagocytosis of Salmonella typhimurium on apoptosis in human macrophages: potential role of Rho-GTPases and Akt. J Leukoc Biol. 2003;74:620–629. doi: 10.1189/jlb.1202586. PubMed DOI

Santos RL, Tsolis RM, Baumler AJ, Smith R III, Adams LG. Salmonella enterica serovar typhimurium induces cell death in bovine monocyte-derived macrophages by early sipB-dependent and delayed sipB-independent mechanisms. Infect Immun. 2001;69:2293–2301. doi: 10.1128/IAI.69.4.2293-2301.2001. PubMed DOI PMC

Santos RL, Tsolis RM, Zhang S, Ficht TA, Baumler AJ, Adams LG. Salmonella-induced cell death is not required for enteritis in calves. Infect Immun. 2001;69:4610–4617. doi: 10.1128/IAI.69.7.4610-4617.2001. PubMed DOI PMC

Drecktrah D, Knodler LA, Galbraith K, Steele-Mortimer O. The Salmonella SPI1 effector SopB stimulates nitric oxide production long after invasion. Cell Microbiol. 2005;7:105–113. doi: 10.1111/j.1462-5822.2004.00436.x. PubMed DOI

Giacomodonato MN, Uzzau S, Bacciu D, Caccuri R, Sarnacki SH, Rubino S, Cerquetti MC. SipA, SopA, SopB, SopD and SopE2 effector proteins of Salmonella enterica serovar Typhimurium are synthesized at late stages of infection in mice. Microbiology. 2007;153:1221–1228. doi: 10.1099/mic.0.2006/002758-0. PubMed DOI

Gong H, Su J, Bai Y, Miao L, Kim K, Yang Y, Liu F, Lu S. Characterization of the expression of Salmonella Type III secretion system factor PrgI, SipA, SipB, SopE2, SpaO, and SptP in cultures and in mice. BMC Microbiol. 2009;9:73. doi: 10.1186/1471-2180-9-73. PubMed DOI PMC

Obregon C, Dreher D, Kok M, Cochand L, Kiama GS, Nicod LP. Human alveolar macrophages infected by virulent bacteria expressing SipB are a major source of active interleukin-18. Infect Immun. 2003;71:4382–4388. doi: 10.1128/IAI.71.8.4382-4388.2003. PubMed DOI PMC

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