Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca<sup>2+</sup>-activated Cl<sup>-</sup> Channels

Leïla Staali; Didier André Colin

doi:doi:10.11648/j.ijmb.20200503.16

| Peer-Reviewed

Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca²⁺-activated Cl^- Channels

Leïla Staali, Didier André Colin

Published in International Journal of Microbiology and Biotechnology (Volume 5, Issue 3)

Received: 1 June 2020 Accepted: 15 June 2020 Published: 29 June 2020

Views: Downloads:

Download PDF

Share This Article

Twitter
Linked In
Facebook

Abstract

The bi-component leukotoxins; γ-hemolysin and Panton and Valentin Leukocidin (PVL) from Staphylococcus aureus induce two independent cellular events 1) the formation of trans-membrane pores not permeable to chloride (Cl^-) ions and 2) the activation of at least, two modes of chloride fluxes (efflux/influx), including pre-existing Ca²⁺-activated Cl^- channels (CaCC) in human polymorphonuclear neutrophils (PMNs). This was investigated by using spectrofluorometry techniques and the chloride-sensitive quencher fluorescent indicator, MQAE (N-(6-methoxyquinolyl) acetoacethyl ester). The ethidium bromide was used as an indicator for the trans-membrane pores formation by staphylococcal leukotoxins. In the absence of extracellular Ca²⁺, HlgA/HlgB, HlgC/HlgB and LukS-PV/LukF-PV leukotoxins from S. aureus induced a massive efflux of chloride (Cl^-) ions. Interestingly, in the presence of extracellular Ca²⁺, the HlgA/HlgB γ-hemolysin provoked a biphasic response of Cl^- movements (efflux/influx). Conversely to HlgA/HlgB and LukS-PV/LukF-PV, HlgC/HlgB leukotoxins did not induce any Cl^- movement under this condition (e.g. in the presence of extracellular Ca²⁺). The potent Cl^- channel inhibitor, DIDS, did inhibit significantly the Cl^- fluxes caused by all pairs of staphylococcal leukotoxins tested in both conditions. In the present study, we found that the inhibitory effect of flufenamic acid, known as a Cl^- channel inhibitor, was restricted only to the Ca²⁺-dependent Cl^- influx triggered only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins. These findings might suggest that, Cl^- fluxes in human neutrophils did involve at least, two different types of Cl^- pathways, depending on the absence or presence of extracellular Ca²⁺. Both Cl^- channels blockers, DIDS and flufenamic acid did not alter the pores formation by staphylococcal leukotoxins. Furthermore, under conditions when the membrane pores formation was blocked by divalent ions (Ca²⁺ and/or Zn²⁺), Cl^- ions movements were still observed. Taken together, our results strongly provide an evidence that: i) trans-membrane pores formed by staphylococcal leukotoxins: HlgA/HlgB, HlgC/HlgB (γ-hemolysin) and LukS-PV/LukF-PV (PVL) do not drive Cl^- ions fluxes ii) at least, two different types of Cl^- ions pathways are activated, depending on the absence or presence of extracellular Ca²⁺, including Ca²⁺-activated Cl^- channels (CaCC) and, iii) Ca²⁺-activated Cl^- channels are mediated only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins.

Published in	International Journal of Microbiology and Biotechnology (Volume 5, Issue 3)
DOI	10.11648/j.ijmb.20200503.16
Page(s)	110-119
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Pore-forming Toxin, S. aureus, Leukotoxin, Cl ^- channels, γ-hemolysin, Panton-Valentin Leukocidin, Neutrophils, Spectrofluorometry

References

[1]	Prévost G, Cribier B, Couppié P, Petiau P, Supersac G, Finck-Barbancon V, Monteil H, Piémont Y (1995) Panton-Valentine leucocidin and gamma-hemolysin from Staphylococcus aureus ATCC49775 are encoded by distinct loci and have different biological activities. Infect. Immun. 63: 4121-4129.
[2]	Finck-Barbancon V, Prévost G, Piémont Y (1991) Improved purification of leukocidin from Staphylococcus aureus and toxin distribution among hospital strains. Res. Microbiol. 142: 75-85.
[3]	Cribier B, Prévost G, Couppié P, Finck-Barbancon V, Grosshans E, Piémont Y (1992) Staphylococcus aureus leukocidin: a new virulence factor in cutaneous infections? An epidemiological and experimental study. Dermatology 185: 175-180.
[4]	Couppié P, Cribier B, Prévost G, Grosshans E, Piemont Y (1994) Leukocidin from Staphylococcus aureus and cutaneous infections: an epidemiological study. Arch. Dermatol. (130): 1208-1209.
[5]	Colin DA, Mazurier I, Sire S, Finck-Barbançon V (1994) Interaction of the two components of leukocicin from Staphylococcus aureus with human polymorphonuclear leukocyte membranes: sequenctiel binding and subsequent activation. Infect. Immun. 62: 3184-3188.
[6]	Guaduchon V, Werner S, Prévost G, Monteil H, Colin DA (2001) Flow cytometry determination of Panton-Valentin leukocidin S component binding. Infect. Immun. 69: 2390-2395.
[7]	Staali L, Monteil H, Colin DA (1998) The pore-forming leukotoxins from Staphylococcus aureus open Ca²⁺ channels in human polymorphonuclear neutrophils. J. Membr. Biol. 162: 209-216.
[8]	Finck-Barbançon V, Duportail G, Meunier O, Colin DA (1993) Pore formation by a two-component leukocidin from Staphylococcus aureus within the membrane of human polymorphonuclear leukocytes. Biochim. Biophys. Acta. 1128: 275-282.
[9]	Ferreras M, Hoper F, Dalla Serra M, Colin DA, Prévost G, Menestrina G (1998) The interaction of Staphylococcus aureus bi-component γ-hemolysin and leucocidins with cells and lipid membranes. Biochim. Biophys. Acta 1414: 108-126.
[10]	Pedelacq JD, Maveyraud L, Prevost G, Baba-Moussa L, Gonzalez A, Courcelle E, Shepard W, Monteil H, Samama JP, Mourey L (1999) The structure of Staphylococcus aureus leucocidin component (LukF-PV) reveals the fold of the water-soluble species of a family of transmembrane pore-forming toxins. Structure 7: 277-287.
[11]	Staali L, Monteil H, Colin DA (1998) Action mechanism of staphylococcal bi-component leucotoxins. Toxicon 36 (12): 1746.
[12]	Staali L, Colin DA (2020) The pore-forming leukotoxins from S. aureus involve Ca²⁺-activated Ca²⁺ channels and other types of Ca²⁺ channels in Ca²⁺ entry into neutrophils. International Journal of Microbiology and Biotechnology. 5 (2): 55-68.
[13]	Colin DA, Monteil H (2003) Control of the oxidative burst of human neutrophils by staphylococcal leukotoxins. Infection and Immunity. 71 (7): 3724-3729.
[14]	Krause KH, Welsh MJ (1990) Voltage-dependent and Ca²⁺-activated ion channels in human neutrophils. J. Clin. Invest. 85: 491-498.
[15]	Schumann L, Gardner P, Raffin TA (1993) Recombinant human tumor necrosis factor α induces calcium oscillation and calcium-activated chloride current inn human neutrophils. J. Biol. Chem. 268: 2134-2140.
[16]	Schumann MA, Raffin TA (1994) Activation of voltage-dependent chloride current in human neutrophils by phorbol 12-myristate 13-acetate and formyl-methionyl-leucyl-phenylalanine. The role of protein kinase. J. Biol. Chem. 269: 2389-2398.
[17]	Simchowitz L, Textor J, Cragoe EJ (1993) Cell volume regulation in human neutrophils: 2-(aminoethyl) phenols as Cl^- channel inhibitors. Am. J. Physiol. 265: C143-155.
[18]	Gallin EK (1991) Ion channels in leukocytes. Physiol. Rev. 3: 775-811.
[19]	Koncz C, Daugirdas J (1994) Use of MQAE for measurement of intracellular [Cl^-] in cultured aortic smouth muscle cells. Am. J. Physiol. 267: H2114-2123.
[20]	Ikeuchi Y, Kogiso H, Hosogi S, Tanaka S, Shimmamoto C, Inui T, Nakahari T, Marunaka Y (2018) Measurement of [Cl^-] unaffected by the cell volume change using MQAE-based two-photon microscopy in airway ciliary cells of mice. The Journal of Physiological Sciences 68: 191-199.
[21]	Shimizu Y, Daniels RH, Elmore MA, Finnen MJ, Hill ME, Lackie JM (1993) Agonist-stimuated Cl- efflux from human neutrophils: a common phenomenon during neutrophil activation. Biochem. Pharmacol. 45: 1743-1751.
[22]	Menegazzi R, Busetto S, Dri P, Cramer R, Patriarca P (1996) Chloride ion efflux regulates adherence, spreading, and respiratory burst of neutrophils stimulated by tumor necrosis factor-α (TNF) on biologic surfaces J. Cell Biol. 135: 511-522.
[23]	Geddes CD, Apperson K, Karolin J, Birch DJ (2001) Chloride-sensitive fluorescent indicators. Anal. Biochem. 293 (1): 60-66.
[24]	West MR, Molloy CR (1996) A microplate assay measuring chloride ion channel activity. Anal. Biochem. 241: 51-58.
[25]	Phipps DJ, Branch DR, Schlichter LC (1996) Chloride channel blockers inhibits T lymphocytes activation and signaling. Cell Signal 8: 141-149.
[26]	Greenwood I, Large W (1995) Comparison of the effects of fenamates on Ca²⁺-activated chloride and potassium currents in rabbit portal vein smouth muscle cells. Br. J. Pharmacol. 116: 2939-2948.
[27]	Busetto S, Trevisan E, Decleva E, Dri P, Meneqazzi R (2007) Chloride movements in human neutrophils during phagocytosis: characterization and relationship to granule release. The journal of Immunology 179: 4110-4124.
[28]	Menegazzi R, Busetto S, Decleva E, Cramer R, Dri P, Patriarca P (1999) Triggering of chloride ion efflux from human neutrophils as a novel function of leukocyte β2 intergrins: relationship with spreading and activation of the respiratory burst. J. immunol. 162: 423-434.
[29]	Engblom AC, Akerman KE (1993) Determination of the intracellular free chloride concentration in rat brain synaptoneurosomes using a chloride-sensitive fluorescent indicator. Biochem. Biophys. Acta 1153 (2): 262-266.
[30]	Kanno T, Takishima T (1990) Chloride and potassium channel in U937 human monocytes. J. Membr. Biol. 116: 149-161.
[31]	Simchowitz L (1986) Chloride movements in human neutrophils: diffusion, exchange and active transport. J. Gen. Phys. 88: 167.
[32]	Simchowitz L (1990) Special topic: ion movements in leukocytes. Annu. Rev. Physiol. 52: 363-364.
[33]	Simchowitz L, Bibb JA (1990) Functional analysis of the modes of anion transport in neutrophils and HL-60 cells. Annu. Rev. Physiol. 52: 381-397.
[34]	Di Fulvio M, Aguilar-Bryan L (2019) Chloride transporters and channels in β-cell physiology: revisiting a 40-year-old model. Biochemical Society Transactions 47: 1843-1855.
[35]	Chao AC, Dix JA, Sellers MC, Verkman AS (1999) Fluorescence measurement of chloride transport in monolayer cultured cells. Biophys. J. 56: 1071-1081.
[36]	Kankaanranta H, Moilanen E (1995) Flufenamic and tolfenamic acids inhibit calcium influx in human polymorphonuclear leukocytes. Mol. Pharmacol. 47: 1006-1013.
[37]	Eberhardson M, Patterson S, Grapengiesser E (2000) Microfluorometric analysis of Cl^- permeability ad its relation to oxcillatory Ca²⁺ signaling in glucose-stimulated pancreatic β-cells. Cellular Signalling 12 (11-12): 781-786.
[38]	Andersson C, Roomans GM (2002) Determination of chloride efflux by X-ray microanalysis versus MQAE-fluorescence. Microsc. Res. Tech. 59 (6): 531-532.

Cite This Article

Plain Text BibTeX RIS

APA Style

Leïla Staali, Didier André Colin. (2020). Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels. International Journal of Microbiology and Biotechnology, 5(3), 110-119. https://doi.org/10.11648/j.ijmb.20200503.16

Copy | Download

ACS Style

Leïla Staali; Didier André Colin. Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels. Int. J. Microbiol. Biotechnol. 2020, 5(3), 110-119. doi: 10.11648/j.ijmb.20200503.16

Copy | Download

AMA Style

Leïla Staali, Didier André Colin. Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels. Int J Microbiol Biotechnol. 2020;5(3):110-119. doi: 10.11648/j.ijmb.20200503.16

Copy | Download

@article{10.11648/j.ijmb.20200503.16,
  author = {Leïla Staali and Didier André Colin},
  title = {Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels},
  journal = {International Journal of Microbiology and Biotechnology},
  volume = {5},
  number = {3},
  pages = {110-119},
  doi = {10.11648/j.ijmb.20200503.16},
  url = {https://doi.org/10.11648/j.ijmb.20200503.16},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmb.20200503.16},
  abstract = {The bi-component leukotoxins; γ-hemolysin and Panton and Valentin Leukocidin (PVL) from Staphylococcus aureus induce two independent cellular events 1) the formation of trans-membrane pores not permeable to chloride (Cl-) ions and 2) the activation of at least, two modes of chloride fluxes (efflux/influx), including pre-existing Ca2+-activated Cl- channels (CaCC) in human polymorphonuclear neutrophils (PMNs). This was investigated by using spectrofluorometry techniques and the chloride-sensitive quencher fluorescent indicator, MQAE (N-(6-methoxyquinolyl) acetoacethyl ester). The ethidium bromide was used as an indicator for the trans-membrane pores formation by staphylococcal leukotoxins. In the absence of extracellular Ca2+, HlgA/HlgB, HlgC/HlgB and LukS-PV/LukF-PV leukotoxins from S. aureus induced a massive efflux of chloride (Cl-) ions. Interestingly, in the presence of extracellular Ca2+, the HlgA/HlgB γ-hemolysin provoked a biphasic response of Cl- movements (efflux/influx). Conversely to HlgA/HlgB and LukS-PV/LukF-PV, HlgC/HlgB leukotoxins did not induce any Cl- movement under this condition (e.g. in the presence of extracellular Ca2+). The potent Cl- channel inhibitor, DIDS, did inhibit significantly the Cl- fluxes caused by all pairs of staphylococcal leukotoxins tested in both conditions. In the present study, we found that the inhibitory effect of flufenamic acid, known as a Cl- channel inhibitor, was restricted only to the Ca2+-dependent Cl- influx triggered only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins. These findings might suggest that, Cl- fluxes in human neutrophils did involve at least, two different types of Cl- pathways, depending on the absence or presence of extracellular Ca2+. Both Cl- channels blockers, DIDS and flufenamic acid did not alter the pores formation by staphylococcal leukotoxins. Furthermore, under conditions when the membrane pores formation was blocked by divalent ions (Ca2+ and/or Zn2+), Cl- ions movements were still observed. Taken together, our results strongly provide an evidence that: i) trans-membrane pores formed by staphylococcal leukotoxins: HlgA/HlgB, HlgC/HlgB (γ-hemolysin) and LukS-PV/LukF-PV (PVL) do not drive Cl- ions fluxes ii) at least, two different types of Cl- ions pathways are activated, depending on the absence or presence of extracellular Ca2+, including Ca2+-activated Cl- channels (CaCC) and, iii) Ca2+-activated Cl- channels are mediated only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins.},
 year = {2020}
}

Copy | Download

TY  - JOUR
T1  - Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels
AU  - Leïla Staali
AU  - Didier André Colin
Y1  - 2020/06/29
PY  - 2020
N1  - https://doi.org/10.11648/j.ijmb.20200503.16
DO  - 10.11648/j.ijmb.20200503.16
T2  - International Journal of Microbiology and Biotechnology
JF  - International Journal of Microbiology and Biotechnology
JO  - International Journal of Microbiology and Biotechnology
SP  - 110
EP  - 119
PB  - Science Publishing Group
SN  - 2578-9686
UR  - https://doi.org/10.11648/j.ijmb.20200503.16
AB  - The bi-component leukotoxins; γ-hemolysin and Panton and Valentin Leukocidin (PVL) from Staphylococcus aureus induce two independent cellular events 1) the formation of trans-membrane pores not permeable to chloride (Cl-) ions and 2) the activation of at least, two modes of chloride fluxes (efflux/influx), including pre-existing Ca2+-activated Cl- channels (CaCC) in human polymorphonuclear neutrophils (PMNs). This was investigated by using spectrofluorometry techniques and the chloride-sensitive quencher fluorescent indicator, MQAE (N-(6-methoxyquinolyl) acetoacethyl ester). The ethidium bromide was used as an indicator for the trans-membrane pores formation by staphylococcal leukotoxins. In the absence of extracellular Ca2+, HlgA/HlgB, HlgC/HlgB and LukS-PV/LukF-PV leukotoxins from S. aureus induced a massive efflux of chloride (Cl-) ions. Interestingly, in the presence of extracellular Ca2+, the HlgA/HlgB γ-hemolysin provoked a biphasic response of Cl- movements (efflux/influx). Conversely to HlgA/HlgB and LukS-PV/LukF-PV, HlgC/HlgB leukotoxins did not induce any Cl- movement under this condition (e.g. in the presence of extracellular Ca2+). The potent Cl- channel inhibitor, DIDS, did inhibit significantly the Cl- fluxes caused by all pairs of staphylococcal leukotoxins tested in both conditions. In the present study, we found that the inhibitory effect of flufenamic acid, known as a Cl- channel inhibitor, was restricted only to the Ca2+-dependent Cl- influx triggered only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins. These findings might suggest that, Cl- fluxes in human neutrophils did involve at least, two different types of Cl- pathways, depending on the absence or presence of extracellular Ca2+. Both Cl- channels blockers, DIDS and flufenamic acid did not alter the pores formation by staphylococcal leukotoxins. Furthermore, under conditions when the membrane pores formation was blocked by divalent ions (Ca2+ and/or Zn2+), Cl- ions movements were still observed. Taken together, our results strongly provide an evidence that: i) trans-membrane pores formed by staphylococcal leukotoxins: HlgA/HlgB, HlgC/HlgB (γ-hemolysin) and LukS-PV/LukF-PV (PVL) do not drive Cl- ions fluxes ii) at least, two different types of Cl- ions pathways are activated, depending on the absence or presence of extracellular Ca2+, including Ca2+-activated Cl- channels (CaCC) and, iii) Ca2+-activated Cl- channels are mediated only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins.
VL  - 5
IS  - 3
ER  -

Copy | Download

Author Information

Leïla Staali
Didier André Colin

Bacteriology Institute of Medical Faculty, Louis Pasteur University, Strasbourg, France

Download PDF

Sections

Plain Text BibTeX RIS

APA Style

Leïla Staali, Didier André Colin. (2020). Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels. International Journal of Microbiology and Biotechnology, 5(3), 110-119. https://doi.org/10.11648/j.ijmb.20200503.16

Copy | Download

ACS Style

Leïla Staali; Didier André Colin. Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels. Int. J. Microbiol. Biotechnol. 2020, 5(3), 110-119. doi: 10.11648/j.ijmb.20200503.16

Copy | Download

AMA Style

Leïla Staali, Didier André Colin. Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels. Int J Microbiol Biotechnol. 2020;5(3):110-119. doi: 10.11648/j.ijmb.20200503.16

Copy | Download

@article{10.11648/j.ijmb.20200503.16,
  author = {Leïla Staali and Didier André Colin},
  title = {Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels},
  journal = {International Journal of Microbiology and Biotechnology},
  volume = {5},
  number = {3},
  pages = {110-119},
  doi = {10.11648/j.ijmb.20200503.16},
  url = {https://doi.org/10.11648/j.ijmb.20200503.16},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmb.20200503.16},
  abstract = {The bi-component leukotoxins; γ-hemolysin and Panton and Valentin Leukocidin (PVL) from Staphylococcus aureus induce two independent cellular events 1) the formation of trans-membrane pores not permeable to chloride (Cl-) ions and 2) the activation of at least, two modes of chloride fluxes (efflux/influx), including pre-existing Ca2+-activated Cl- channels (CaCC) in human polymorphonuclear neutrophils (PMNs). This was investigated by using spectrofluorometry techniques and the chloride-sensitive quencher fluorescent indicator, MQAE (N-(6-methoxyquinolyl) acetoacethyl ester). The ethidium bromide was used as an indicator for the trans-membrane pores formation by staphylococcal leukotoxins. In the absence of extracellular Ca2+, HlgA/HlgB, HlgC/HlgB and LukS-PV/LukF-PV leukotoxins from S. aureus induced a massive efflux of chloride (Cl-) ions. Interestingly, in the presence of extracellular Ca2+, the HlgA/HlgB γ-hemolysin provoked a biphasic response of Cl- movements (efflux/influx). Conversely to HlgA/HlgB and LukS-PV/LukF-PV, HlgC/HlgB leukotoxins did not induce any Cl- movement under this condition (e.g. in the presence of extracellular Ca2+). The potent Cl- channel inhibitor, DIDS, did inhibit significantly the Cl- fluxes caused by all pairs of staphylococcal leukotoxins tested in both conditions. In the present study, we found that the inhibitory effect of flufenamic acid, known as a Cl- channel inhibitor, was restricted only to the Ca2+-dependent Cl- influx triggered only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins. These findings might suggest that, Cl- fluxes in human neutrophils did involve at least, two different types of Cl- pathways, depending on the absence or presence of extracellular Ca2+. Both Cl- channels blockers, DIDS and flufenamic acid did not alter the pores formation by staphylococcal leukotoxins. Furthermore, under conditions when the membrane pores formation was blocked by divalent ions (Ca2+ and/or Zn2+), Cl- ions movements were still observed. Taken together, our results strongly provide an evidence that: i) trans-membrane pores formed by staphylococcal leukotoxins: HlgA/HlgB, HlgC/HlgB (γ-hemolysin) and LukS-PV/LukF-PV (PVL) do not drive Cl- ions fluxes ii) at least, two different types of Cl- ions pathways are activated, depending on the absence or presence of extracellular Ca2+, including Ca2+-activated Cl- channels (CaCC) and, iii) Ca2+-activated Cl- channels are mediated only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins.},
 year = {2020}
}

Copy | Download

TY  - JOUR
T1  - Bi-component Staphylococcal Leukotoxins Induce Chloride Ions Fluxes in Human Neutrophils: Opening of Ca2+-activated Cl- Channels
AU  - Leïla Staali
AU  - Didier André Colin
Y1  - 2020/06/29
PY  - 2020
N1  - https://doi.org/10.11648/j.ijmb.20200503.16
DO  - 10.11648/j.ijmb.20200503.16
T2  - International Journal of Microbiology and Biotechnology
JF  - International Journal of Microbiology and Biotechnology
JO  - International Journal of Microbiology and Biotechnology
SP  - 110
EP  - 119
PB  - Science Publishing Group
SN  - 2578-9686
UR  - https://doi.org/10.11648/j.ijmb.20200503.16
AB  - The bi-component leukotoxins; γ-hemolysin and Panton and Valentin Leukocidin (PVL) from Staphylococcus aureus induce two independent cellular events 1) the formation of trans-membrane pores not permeable to chloride (Cl-) ions and 2) the activation of at least, two modes of chloride fluxes (efflux/influx), including pre-existing Ca2+-activated Cl- channels (CaCC) in human polymorphonuclear neutrophils (PMNs). This was investigated by using spectrofluorometry techniques and the chloride-sensitive quencher fluorescent indicator, MQAE (N-(6-methoxyquinolyl) acetoacethyl ester). The ethidium bromide was used as an indicator for the trans-membrane pores formation by staphylococcal leukotoxins. In the absence of extracellular Ca2+, HlgA/HlgB, HlgC/HlgB and LukS-PV/LukF-PV leukotoxins from S. aureus induced a massive efflux of chloride (Cl-) ions. Interestingly, in the presence of extracellular Ca2+, the HlgA/HlgB γ-hemolysin provoked a biphasic response of Cl- movements (efflux/influx). Conversely to HlgA/HlgB and LukS-PV/LukF-PV, HlgC/HlgB leukotoxins did not induce any Cl- movement under this condition (e.g. in the presence of extracellular Ca2+). The potent Cl- channel inhibitor, DIDS, did inhibit significantly the Cl- fluxes caused by all pairs of staphylococcal leukotoxins tested in both conditions. In the present study, we found that the inhibitory effect of flufenamic acid, known as a Cl- channel inhibitor, was restricted only to the Ca2+-dependent Cl- influx triggered only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins. These findings might suggest that, Cl- fluxes in human neutrophils did involve at least, two different types of Cl- pathways, depending on the absence or presence of extracellular Ca2+. Both Cl- channels blockers, DIDS and flufenamic acid did not alter the pores formation by staphylococcal leukotoxins. Furthermore, under conditions when the membrane pores formation was blocked by divalent ions (Ca2+ and/or Zn2+), Cl- ions movements were still observed. Taken together, our results strongly provide an evidence that: i) trans-membrane pores formed by staphylococcal leukotoxins: HlgA/HlgB, HlgC/HlgB (γ-hemolysin) and LukS-PV/LukF-PV (PVL) do not drive Cl- ions fluxes ii) at least, two different types of Cl- ions pathways are activated, depending on the absence or presence of extracellular Ca2+, including Ca2+-activated Cl- channels (CaCC) and, iii) Ca2+-activated Cl- channels are mediated only by HlgA/HlgB and LukS-PV/LukF-PV leukotoxins.
VL  - 5
IS  - 3
ER  -

Copy | Download