Wikipedia

Pertussis toxin

Pertussis toxin(PT) is a protein-basedAB5-typeexotoxinproduced by thebacteriumBordetella pertussis,[2]which causeswhooping cough.PT is involved in the colonization of therespiratory tractand the establishment of infection.[3]Research suggests PT may have a therapeutic role in treating a number of common human ailments, including hypertension,[4]viral infection,[5]and autoimmunity.[6][7][8]

Pertussis toxin, subunit 1
The crystal structure of pertussis toxin,[1]
Identifiers
SymbolPertussis_S1
PfamPF02917
InterProIPR003898
SCOP21bcp/SCOPe/SUPFAM
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary
Pertussis toxin, subunit 2 and 3
Identifiers
SymbolPertussis_S2S3
PfamPF02918
InterProIPR003899
SCOP21bcp/SCOPe/SUPFAM
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary
Pertussis toxin, subunit 4
Identifiers
SymbolPertus-S4-tox
PfamPF09275
InterProIPR015355
SCOP21prt/SCOPe/SUPFAM
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary
Pertussis toxin, subunit 5
Identifiers
SymbolPertus-S5-tox
PfamPF09276
InterProIPR015356
SCOP21prt/SCOPe/SUPFAM
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary

History

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PT clearly plays a central role in thepathogenesisofpertussisalthough this was discovered only in the early 1980s. The appearance of pertussis is quite recent, compared with other epidemic infectious diseases. The earliest mention of pertussis, or whooping cough, is of an outbreak in Paris in 1414. This was published in Moulton's The Mirror of Health, in 1640. Another epidemic of pertussis took place in Paris in 1578 and was described by a contemporary observer,Guillaume de Baillou.Pertussis was well known throughout Europe by the middle of the 18th century. Jules Bordet and Octave Gengou described in 1900 the finding of a new “ovoid bacillus” in the sputum of a 6-month-old infant with whooping cough. They were also the first to cultivateBordetella pertussisat thePasteur Institutein Brussels in 1906.[9]

One difference between the different species ofBordetellais thatB. pertussisproduces PT and the other species do not.Bordetella parapertussisshows the most similarity toB. pertussisand was therefore used for research determining the role of PT in causing the typical symptoms of whooping cough. Rat studies showed the development of paroxysmal coughing, a characteristic for whooping cough, occurred in rats infected withB. pertussis.Rats infected withB. parapertussisor a PT-deficient mutant ofB. pertussisdid not show this symptom; neither of these two strains produced PT.[10]

Structure

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A large group of bacterialexotoxinsare referred to as "A/B toxins", in essence because they are formed from two subunits.[11]The "A" subunit possesses enzyme activity, and is transferred to the host cell following a conformational change in the membrane-bound transport "B" subunit.[11]Pertussis toxin is an exotoxin with six subunits (namedS1throughS5—each complex contains two copies ofS4).[12][13]The subunits are arranged inA-Bstructure: theAcomponent isenzymatically activeand is formed from the S1 subunit, while theBcomponent is thereceptor-binding portion and is made up of subunits S2–S5.[13]The subunits are encoded byptxgenes encoded on a large PToperonthat also includes additional genes that encode Ptl proteins. Together, these proteins form the PT secretion complex.[14]

Mechanism of pathogenesis

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PT is released fromB. pertussisin an inactive form. Following PT binding to acell membrane receptor,it is taken up in anendosome,after which it undergoes retrograde transport to thetrans-Golgi networkandendoplasmic reticulum.[15]At some point during this transport, the A subunit (or protomer) becomes activated, perhaps through the action ofglutathioneandATP.[12][16]PT catalyzes theADP-ribosylationof theαisubunitsof theheterotrimeric G protein.This prevents the G proteins from interacting withG protein-coupled receptorson thecell membrane,thus interfering with intracellular communication.[17]The Gi subunits remain locked in their GDP-bound, inactive state, thus unable to inhibit adenylate cyclase activity, leading to increased cellular concentrations of cAMP.

Increased intracellular cAMP affects normal biological signaling. The toxin causes several systemic effects, among which is an increased release ofinsulin,causinghypoglycemia.Whether the effects of pertussis toxin are responsible for the paroxysmal cough remains unknown.[18]

As a result of this unique mechanism, PT has also become widely used as a biochemical tool to ADP-ribosylate GTP-binding proteins in the study of signal transduction.[1]It has also become an essential component of new acellular vaccines.[1]

Effects on the immune system

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PT has been shown to affect the innate immune response. It inhibits the early recruitment ofneutrophilsandmacrophages,and interferes with earlychemokineproduction and neutrophilchemotaxis.[19]Chemokines are signalling molecules produced by infected cells and attract neutrophils and macrophages. Neutrophil chemotaxis is thought to be disrupted by inhibiting G-protein-coupled chemokine receptors by the ADP-ribosylation of Giproteins.[20]

Due to the disrupted signalling pathways, synthesis of chemokines will be affected. This will prevent the infected cell from producing them and thereby inhibiting recruitment of neutrophils. Under normal circumstances, alveolar macrophages and other lung cells produce a variety of chemokines. PT has been found to inhibit the early transcription of keratinocyte-derived chemokine, macrophage inflammatory protein 2 andLPS-induced CXC chemokine.[20]Eventually, PT causeslymphocytosis,one of the systemic manifestations of whooping cough.[21]

PT, a decisive virulence determinant ofB. pertussis,is able to cross the blood–brain barrier by increasing its permeability.[22]As a result, PT can cause severe neurological complications; however, recently it has been found that the medicinal usage ofPertussistoxin can promote the development of regulatory T cells and prevent central nervous system autoimmune disease, such as multiple sclerosis.[23]

Metabolism

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PT is known to dissociate into two parts in the endoplasmic reticulum (ER): the enzymatically active A subunit (S1) and the cell-binding B subunit. The two subunits are separated by proteolic cleavage. The B subunit will undergo ubiquitin-dependent degradation by the 26Sproteasome.However, the A subunit lackslysineresidues, which are essential forubiquitin-dependent degradation. Therefore, PT subunit A will not be metabolized like most other proteins.[24]

PT is heat-stable and protease-resistant, but once the A and B are separated, these properties change. The B subunit will stay heat-stable at temperatures up to 60 °C, but it is susceptible to protein degradation. PT subunit A, on the other hand, is less susceptible to ubiquitin-dependent degradation, but is unstable at temperature of 37 °C. This facilitates unfolding of the protein in the ER and tricks the cell into transporting the A subunit to the cytosol, where normally unfolded proteins will be marked for degradation. So, the unfolded conformation will stimulate theERAD-mediated translocation of PT A into the cytosol. Once in the cytosol, it can bind to NAD and form a stable, folded protein again. Being thermally unstable is also the Achilles heel of PT subunit A. As always, there is an equilibrium between the folded and unfolded states. When the protein is unfolded, it is susceptible to degradation by the 20S proteasome, which can degrade only unfolded proteins.[24]

PT and vaccines

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Since the introduction of pertussis vaccines in the 1940s and 1950s, different genetic changes have been described surrounding the pertussis toxin.

Emergence ofptxP3

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ptxPis the pertussis toxin's promoter gene. There is a well documented emergence and global spread ofptxP3strains evolving from and replacing the nativeptxP1strains,[25]associated with an increased production of the toxin, and thus an increased virulence.[26]Such spread has been documented in multiple countries, and sometimes but not always linked to the resurgence of pertussis in the end of the 20th century. Countries with a documented spread ofptxP3include Australia,[26][27]Denmark,[28]Finland,[29]Iran,[30]Italy,[31]Japan,[32]the Netherlands,[33]and Sweden.[34]

See also

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References

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  1. ^abcStein PE, Boodhoo A, Armstrong GD, Cockle SA, Klein MH, Read RJ (January 1994)."The crystal structure of pertussis toxin".Structure.2(1): 45–57.doi:10.1016/S0969-2126(00)00007-1.PMID8075982.
  2. ^Ryan KJ, Ray CG, eds. (2004).Sherris Medical Microbiology(4th ed.). McGraw Hill.ISBN0-8385-8529-9.
  3. ^Carbonetti NH, Artamonova GV, Mays RM, Worthington ZE (November 2003)."Pertussis Toxin Plays an Early Role in Respiratory Tract Colonization by Bordetella pertussis".Infect. Immun.71(11): 6358–66.doi:10.1128/IAI.71.11.6358-6366.2003.PMC219603.PMID14573656.
  4. ^Kost C, Herzer W, Li P, Jackson E (1999). "Pertussis toxin-sensitive G-proteins and regulation of blood pressure in the spontaneously hypertensive rat".Clin Exp Pharmacol Physiol.26(5–6): 449–55.doi:10.1046/j.1440-1681.1999.03058.x.PMID10386237.S2CID12902466.
  5. ^Alfano M, Pushkarsky T, Poli G, Bukrinsky M (2000)."The B-Oligomer of Pertussis Toxin Inhibits Human Immunodeficiency Virus Type 1 Replication at Multiple Stages".J Virol.74(18): 8767–70.doi:10.1128/JVI.74.18.8767-8770.2000.PMC116391.PMID10954581.
  6. ^Bagley K, Abdelwahab S, Tuskan R, Fouts T, Lewis G (2002). "Pertussis toxin and the adenylate cyclase toxin from Bordetella pertussis activate human monocyte-derived dendritic cells and dominantly inhibit cytokine production through a cAMP-dependent pathway".J Leukoc Biol.72(5): 962–9.doi:10.1189/jlb.72.5.962.PMID12429718.S2CID16457655.
  7. ^Locht C, Keith JM (1986)."Pertussis toxin gene: nucleotide sequence and genetic organization".Science.232(4755): 1258–1264.Bibcode:1986Sci...232.1258L.doi:10.1126/science.3704651.PMID3704651.
  8. ^Rappuoli R, Nicosia A, Perugini M, Franzini C, Casagli MC, Borri MG, Antoni G, Almoni M, Neri P, Ratti G (1986)."Cloning and sequencing of the pertussis toxin genes: operon structure and gene duplication".Proc. Natl. Acad. Sci. U.S.A.83(13): 4631–4635.Bibcode:1986PNAS...83.4631N.doi:10.1073/pnas.83.13.4631.PMC323795.PMID2873570.
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  12. ^abKaslow HR, Burns DL (June 1992)."Pertussis toxin and target eukaryotic cells: binding, entry, and activation".FASEB J.6(9): 2684–90.doi:10.1096/fasebj.6.9.1612292.PMID1612292.S2CID20607696.
  13. ^abLocht C, Antoine R (1995). "A proposed mechanism of ADP-ribosylation catalyzed by the pertussis toxin S1 subunit".Biochimie.77(5): 333–40.doi:10.1016/0300-9084(96)88143-0.PMID8527486.
  14. ^Weiss A, Johnson F, Burns D (1993)."Molecular characterization of an operon required for pertussis toxin secretion".Proc Natl Acad Sci U S A.90(7): 2970–4.Bibcode:1993PNAS...90.2970W.doi:10.1073/pnas.90.7.2970.PMC46218.PMID8464913.
  15. ^Plaut RD, Carbonetti NH (May 2008)."Retrograde transport of pertussis toxin in the mammalian cell".Cell. Microbiol.10(5): 1130–9.doi:10.1111/j.1462-5822.2007.01115.x.PMID18201245.S2CID22900943.
  16. ^Finger H, von Koenig CH (1996)."Bordetella".In Barron S, et al. (eds.).Barron's Medical Microbiology(4th ed.). Univ of Texas Medical Branch.ISBN0-9631172-1-1.PMID21413270.
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  19. ^Bestebroer J, De Haas CJ, Van Strijp JA (2010)."How microorganisms avoid phagocyte attraction".FEMS Microbiology Reviews.34(3): 395–414.doi:10.1111/j.1574-6976.2009.00202.x.PMID20059549.
  20. ^abAndreasen, C. & Carbonetti, N.H. (2008)."Pertussis Toxin Inhibits Early Chemokine Production To Delay Neutrophil Recruitment in Response to Bordetella pertussis Respiratory Tract Infection in Mice".Infection and Immunity.76(11): 5139–5148.doi:10.1128/IAI.00895-08.PMC2573337.PMID18765723.
  21. ^Cherry, J.D.; Baraff, LJ; Hewlett, E (1989)."The past, present, and future of pertussis. The role of adults in epidemiology and future control".Western Journal of Medicine.150(3): 319–328.PMC1026455.PMID2660414.
  22. ^Kügler S, Böcker K, Heusipp G, Greune L, Kim KS, Schmidt MA (March 2007). "Pertussis toxin transiently affects barrier integrity, organelle organization and transmigration of monocytes in a human brain microvascular endothelial cell barrier model".Cell. Microbiol.9(3): 619–32.doi:10.1111/j.1462-5822.2006.00813.x.PMID17002784.S2CID6747379.
  23. ^Weber MS, Benkhoucha M, Lehmann-Horn K, et al. (2010). Unutmaz D (ed.)."Repetitive Pertussis Toxin Promotes Development of Regulatory T Cells and Prevents Central Nervous System Autoimmune Disease".PLOS ONE.5(12): e16009.Bibcode:2010PLoSO...516009W.doi:10.1371/journal.pone.0016009.PMC3012729.PMID21209857.
  24. ^abPande AH, Moe D, Jamnadas M, Tatulian SA, Teter K (2006)."The Pertussis Toxin S1 Subunit Is a Thermally Unstable Protein Susceptible to Degradation by the 20S Proteasome".Biochemistry.45(46): 13734–40.doi:10.1021/bi061175+.PMC2518456.PMID17105192.
  25. ^Lam, Connie; Octavia, Sophie; Bahrame, Zahra; Sintchenko, Vitali; Gilbert, Gwendolyn L.; Lan, Ruiting (March 2012)."Selection and emergence of pertussis toxin promoter ptxP3 allele in the evolution of Bordetella pertussis".Infection, Genetics and Evolution.12(2): 492–495.Bibcode:2012InfGE..12..492L.doi:10.1016/j.meegid.2012.01.001.PMID22293463.
  26. ^abMooi, Frits R.; van Loo, Inge H.M.; van Gent, Marjolein; He, Qiushui; Bart, Marieke J.; Heuvelman, Kees J.; de Greeff, Sabine C.; Diavatopoulos, Dimitri; Teunis, Peter; Nagelkerke, Nico; Mertsola, Jussi (2009)."Bordetella pertussis Strains with Increased Toxin Production Associated with Pertussis Resurgence".Emerging Infectious Diseases.15(8): 1206–1213.doi:10.3201/eid1508.081511.ISSN1080-6040.PMC2815961.PMID19751581.S2CID18101684.
  27. ^Lam, Connie; Octavia, Sophie; Ricafort, Lawrence; Sintchenko, Vitali; Gilbert, Gwendolyn L.; Wood, Nicholas; McIntyre, Peter; Marshall, Helen; Guiso, Nicole; Keil, Anthony D.; Lawrence, Andrew (April 2014)."Rapid Increase in Pertactin-deficient Bordetella pertussis Isolates, Australia".Emerging Infectious Diseases.20(4): 626–633.doi:10.3201/eid2004.131478.ISSN1080-6040.PMC3966384.PMID24655754.
  28. ^Petersen, Randi Føns; Dalby, Tine; Dragsted, Ditte Marie; Mooi, Frits; Lambertsen, Lotte (May 2012)."Temporal Trends in Bordetella pertussis Populations, Denmark, 1949–2010".Emerging Infectious Diseases.18(5): 767–774.doi:10.3201/eid1805.110812.ISSN1080-6040.PMC3358084.PMID22515990.
  29. ^Kallonen, T.; Mertsola, J.; Mooi, F.R.; He, Q. (October 2012)."Rapid detection of the recently emerged Bordetella pertussis strains with the ptxP3 pertussis toxin promoter allele by real-time PCR".Clinical Microbiology and Infection.18(10): E377–E379.doi:10.1111/j.1469-0691.2012.04000.x.PMID22909320.
  30. ^Safarchi, Azadeh; Saedi, Samaneh; Octavia, Sophie; Sedaghatpour, Mehdi; Bolourchi, Negin; Tay, Chin Yen; Lamichhane, Binit; Shahcheraghi, Fereshteh; Lan, Ruiting (September 2021)."Evolutionary genomics of recent clinical Bordetella pertussis isolates from Iran: wide circulation of multiple ptxP3 lineages and report of the first ptxP3 filamentous hemagglutinin-negative B. pertussis".Infection, Genetics and Evolution.93:104970.Bibcode:2021InfGE..9304970S.doi:10.1016/j.meegid.2021.104970.PMID34171476.
  31. ^Loconsole, Daniela; De Robertis, Anna Lisa; Morea, Anna; Metallo, Angela; Lopalco, Pier Luigi; Chironna, Maria (May 2018)."Resurgence of Pertussis and Emergence of the Ptxp3 Toxin Promoter Allele in South Italy".Pediatric Infectious Disease Journal.37(5): e126–e131.doi:10.1097/INF.0000000000001804.ISSN0891-3668.PMID28945679.S2CID205692275.
  32. ^Zomer, Aldert; Otsuka, Nao; Hiramatsu, Yukihiro; Kamachi, Kazunari; Nishimura, Naoko; Ozaki, Takao; Poolman, Jan; Geurtsen, Jeroen (2018-05-01)."Bordetella pertussis population dynamics and phylogeny in Japan after adoption of acellular pertussis vaccines".Microbial Genomics.4(5).doi:10.1099/mgen.0.000180.ISSN2057-5858.PMC5994715.PMID29771235.
  33. ^van Gent, Marjolein; Bart, Marieke J.; van der Heide, Han G. J.; Heuvelman, Kees J.; Mooi, Frits R. (2012-09-28). Hozbor, Daniela Flavia (ed.)."Small Mutations in Bordetella pertussis Are Associated with Selective Sweeps".PLOS ONE.7(9): e46407.Bibcode:2012PLoSO...746407V.doi:10.1371/journal.pone.0046407.ISSN1932-6203.PMC3460923.PMID23029513.
  34. ^Advani, Abdolreza; Gustafsson, Lennart; Åhrén, Christina; Mooi, Frits R.; Hallander, Hans O (April 2011)."Appearance of Fim3 and ptxP3-Bordetella pertussis strains, in two regions of Sweden with different vaccination programs".Vaccine.29(18): 3438–3442.doi:10.1016/j.vaccine.2011.02.070.PMID21396900.
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