Regulation of carbon metabolism in staphylococci: The impact of catabolite control protein A and related factors on pathogenicity of Staphylococcus aureus and Staphylococcus epidermidis
Zusammenfassung der Projektergebnisse
Pathogenic bacteria often link virulence factor synthesis with central carbon metabolism. This SPP project aimed at identifying regulatory factors in the clinically important staphylococcal species Staphylococcus aureus and Staphylococcus epidermidis that contribute to the regulation of their virulons in response to central carbon metabolites. Our studies revealed that S. aureus produces at least four regulatory elements to modulate virulence factor synthesis in response to metabolic stimuli, namely the catabolite control protein A (CcpA), catabolite control protein E (CcpE), histidine-containing phosphocarrier protein HPr, and ribose phosphate isomerase regulator c (RpiRc). CcpA, a member of the GalR-LacI repressor family that responds to glycolytic intermediates, was found to alter the transcription of major virulence factors such as -hemolysin, protein A, and toxic shock syndrome toxin, to affect biofilm formation, and to contribute to virulence of S. aureus in glucose-rich environments. CcpA activity itself was found being fine-tuned in S. aureus by serine/threonine protein kinase Stk1, which inhibits the DNA binding activity of CcpA by phosphorylating threonine 18 and 33, respectively, and by HPr, which, if phosphorylated at serine 46, strongly enhances the binding capacity of CcpA towards its DNA target sequences, the catabolite responsive elements. By inactivating the HPr encoding gene ptsH in S. aureus, we could show furthermore that this small phosphocarrier protein is also able to affect central metabolism and virulence in this pathogen independent of its influence on CcpA regulation. Inactivation of ccpA in S. epidermidis revealed that this carbon catabolite-responsive transcription factor is also important for biofilm formation and central carbon metabolism of this notorious implant-associated infection causing pathogen under in vitro conditions. However, CcpA was found to be dispensable for biofilm formation of S. epidermidis in a murine catheter/biofilm infection model, suggesting that biofilm formation of this bacterial species is not regulated by the availability of carbohydrates in vivo. A bioinformatic search for additional carbon catabolite-responsive regulators in S. aureus allowed us to identify CcpE, a LysR-type regulator with homology to the transcription factor CcpC of Bacillus subtilis. Inactivation of ccpE in S. aureus revealed that this regulatory molecule positively affects TCA cycle activity, and modulates the expression of virulence factors and pathogenicity of this pathogen. Specifically, CcpE was found to directly augment the transcription of the aconitase-encoding gene citB and to suppress the transcription of the -hemolysin-encoding gene hla, while transcription of the psma and cap operons were found to be indirectly controlled by this regulator. In line with the transcriptional data, we observed a decrease in capsule formation in the ccpE mutant, while S. aureus cells lacking CcpE produced higher bacterial loads in mice in two different infection models, suggesting that CcpE serves as attenuator of infectivity in S. aureus. A negative effect on virulence of S. aureus was also observed for RpiRc, a putative ribose-responsive regulator that belongs to the RpiR family of transcriptional regulators. Inactivation of rpiRc in S. aureus markedly increased mortality and the bacterial burden of the mutant in mice, and strongly affected capsule formation, hemolytic activity, and protein A expression. By constructing a series of S. aureus double mutants lacking rpiRc and either one of the global regulator-encoding genes agr, sarA, or sigB, we could demonstrate that RpiRc affects the synthesis of virulence determinants in concert with B, SarA, and the bacterial metabolic status to attenuate virulence.
Projektbezogene Publikationen (Auswahl)
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Effect of a glucose impulse on the CcpA regulon in Staphylococcus aureus.
BMC Microbiology, Vol. 9. 2009, Article number: 95.
Seidl K., Müller S., François P., Kriebitzsch C., Schrenzel J., Engelmann S., Bischoff M., Berger-Bächi B.
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CcpA coordinates central metabolism and biofilm formation in Staphylococcus epidermidis. Microbiology, Vol. 157. 2011, Issue 12, pp. 3458–3468.
Sadykov M.R., Hartmann T., Mattes T.A., Hiatt M., Jann N.J., Zhu Y., Ledala N., Landmann R., Herrmann M., Rohde H., Bischoff M., Somerville G.A.
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A novel mode of regulation of the Staphylococcus aureus catabolite control protein A (CcpA) mediated by Stk1 protein phosphorylation. Journal of Biological Chemistry, Vol. 287. 2012, Issue 52, pp. 43607-43619.
Leiba J., Hartmann T., Cluzel M.E., Cohen-Gonsaud M., Delolme F., Bischoff M., Molle V.
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Catabolite control protein E (CcpE) is a LysR-type transcriptional regulator of tricarboxylic acid cycle activity in Staphylococcus aureus. Journal of Biological Chemistry, Vol. 288. 2013, Issue 50, pp. 36116-36128.
Hartmann T., Zhang B., Baronian G., Schulthess B., Homerova D., Grubmüller S., Kutzner E., Gaupp R., Bertram R., Powers R., Eisenreich W., Kormanec J., Herrmann M., Molle V., Somerville G.A., Bischoff M.
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The catabolite control protein E (CcpE) affects virulence determinant production and pathogenesis of Staphylococcus aureus. Journal of Biological Chemistry (JBC) , Vol. 289. 2014, Issue 43, pp. 29701-29711.
Hartmann T., Baronian G., Nippe N., Voss M., Schulthess B., Wolz C., Eisenbeis J., Schmidt-Hohagen K., Gaupp R., Sunderkötter C., Beisswenger C., Bals R., Somerville G.A., Herrmann M., Molle V., Bischoff M.
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Staphylococcus aureus metabolic adaptations during the transition from a daptomycin susceptibility phenotype to a daptomycin nonsusceptibility phenotype. Antimicrobial Agents and Chemotherapy, Vol. 59. 2015, No. 7, pp. 4226-4238.
Gaupp R., Lei S., Reed J.M., Peisker H., Boyle-Vavra S., Bayer A.S., Bischoff M., Herrmann M., Daum R.S., Powers R., Somerville G.A.
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Peptidoglycan Recycling in Gram-Positive Bacteria Is Crucial for Survival in Stationary Phase. mBio, Vol. 7. 2016, No. 5: e00923-16.
Borisova M., Gaupp R., Duckworth A., Schneider A., Dalügge D., Mühleck M., Deubel D., Unsleber S., Yu W., Muth G., Bischoff M., Götz F., Mayer C.
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CcpA Affects Infectivity of Staphylococcus aureus in a Hyperglycemic Environment. Frontiers in Cellular and Infection Microbiology, Sec. Clinical Microbiology, Vol. 7. 2017: 172.
Bischoff M., Wonnenberg B., Nippe N., Nyffenegger-Jann N.J., Voss M., Beisswenger C., Sunderkötter C., Molle V., Dinh Q.T., Lammert F., Bals R., Herrmann M., Somerville G.A., Tschernig T., Gaupp R.
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ClpC affects the intracellular survival capacity of Staphylococcus aureus in non-professional phagocytic cells. Scientific Reports, Vol. 9. 2019, Article number: 16267.
Gunaratnam G., Tuchscherr L., Elhawy M.I., Bertram R., Eisenbeis J., Spengler C., Tschernig T., Löffler B., Somerville G.A., Jacobs K., Herrmann M., Bischoff M.
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Impact of the Histidine-Containing Phosphocarrier Protein HPr on Carbon Metabolism and Virulence in Staphylococcus aureus. Microorganisms, Vol. 9.2021, Issue 3, 466.
Pätzold L, Brausch AC, Bielefeld EL, Zimmer L, Somerville GA, Bischoff M, Gaupp R.
