Involvement of cell surface TG2 in the aggregation of K562 cells triggered by gluten

G. Feriotto, R. Calza, C.M. Bergamini, M. Griffin, Z. Wang, S. Beninati, V. Ferretti, E. Marzola, R. Guerrini, A. Pagnoni, A. Cavazzini, F. Casciano, C. Mischiati

Research output: Contribution to journalArticle

Abstract

Gluten-induced aggregation of K562 cells represents an in vitro model reproducing the early steps occurring in the small bowel of celiac patients exposed to gliadin. Despite the clear involvement of TG2 in the activation of the antigen-presenting cells, it is not yet clear in which compartment it occurs. Herein we study the calcium-dependent aggregation of these cells, using either cell-permeable or cell-impermeable TG2 inhibitors. Gluten induces efficient aggregation when calcium is absent in the extracellular environment, while TG2 inhibitors do not restore the full aggregating potential of gluten in the presence of calcium. These findings suggest that TG2 activity is not essential in the cellular aggregation mechanism. We demonstrate that gluten contacts the cells and provokes their aggregation through a mechanism involving the A-gliadin peptide 31-43. This peptide also activates the cell surface associated extracellular TG2 in the absence of calcium. Using a bioinformatics approach, we identify the possible docking sites of this peptide on the open and closed TG2 structures. Peptide docks with the closed TG2 structure near to the GTP/GDP site, by establishing molecular interactions with the same amino acids involved in stabilization of GTP binding. We suggest that it may occur through the displacement of GTP, switching the TG2 structure from the closed to the active open conformation. Furthermore, docking analysis shows peptide binding with the β-sandwich domain of the closed TG2 structure, suggesting that this region could be responsible for the different aggregating effects of gluten shown in the presence or absence of calcium. We deduce from these data a possible mechanism of action by which gluten makes contact with the cell surface, which could have possible implications in the celiac disease onset.

LanguageEnglish
JournalAmino Acids
VolumeIn press
Early online date3 Oct 2016
DOIs
Publication statusE-pub ahead of print - 3 Oct 2016

Fingerprint

K562 Cells
Glutens
Agglomeration
Calcium
Guanosine Triphosphate
Peptides
Gliadin
Cell Aggregation
Docks
Molecular interactions
Celiac Disease
Antigen-Presenting Cells
Bioinformatics
Computational Biology
Abdomen
Conformations
Stabilization
Chemical activation
Amino Acids

Bibliographical note

The final publication is available at Springer via http://dx.doi.org/10.1007/s00726-016-2339-4

Keywords

  • agglutination
  • gluten
  • K562 cells
  • TG2
  • TG2-inhibitors

Cite this

Feriotto, G. ; Calza, R. ; Bergamini, C.M. ; Griffin, M. ; Wang, Z. ; Beninati, S. ; Ferretti, V. ; Marzola, E. ; Guerrini, R. ; Pagnoni, A. ; Cavazzini, A. ; Casciano, F. ; Mischiati, C. / Involvement of cell surface TG2 in the aggregation of K562 cells triggered by gluten. In: Amino Acids. 2016 ; Vol. In press.
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Feriotto, G, Calza, R, Bergamini, CM, Griffin, M, Wang, Z, Beninati, S, Ferretti, V, Marzola, E, Guerrini, R, Pagnoni, A, Cavazzini, A, Casciano, F & Mischiati, C 2016, 'Involvement of cell surface TG2 in the aggregation of K562 cells triggered by gluten' Amino Acids, vol. In press. https://doi.org/10.1007/s00726-016-2339-4

Involvement of cell surface TG2 in the aggregation of K562 cells triggered by gluten. / Feriotto, G.; Calza, R.; Bergamini, C.M.; Griffin, M.; Wang, Z.; Beninati, S.; Ferretti, V.; Marzola, E.; Guerrini, R.; Pagnoni, A.; Cavazzini, A.; Casciano, F.; Mischiati, C.

In: Amino Acids, Vol. In press, 03.10.2016.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Involvement of cell surface TG2 in the aggregation of K562 cells triggered by gluten

AU - Feriotto, G.

AU - Calza, R.

AU - Bergamini, C.M.

AU - Griffin, M.

AU - Wang, Z.

AU - Beninati, S.

AU - Ferretti, V.

AU - Marzola, E.

AU - Guerrini, R.

AU - Pagnoni, A.

AU - Cavazzini, A.

AU - Casciano, F.

AU - Mischiati, C.

N1 - The final publication is available at Springer via http://dx.doi.org/10.1007/s00726-016-2339-4

PY - 2016/10/3

Y1 - 2016/10/3

N2 - Gluten-induced aggregation of K562 cells represents an in vitro model reproducing the early steps occurring in the small bowel of celiac patients exposed to gliadin. Despite the clear involvement of TG2 in the activation of the antigen-presenting cells, it is not yet clear in which compartment it occurs. Herein we study the calcium-dependent aggregation of these cells, using either cell-permeable or cell-impermeable TG2 inhibitors. Gluten induces efficient aggregation when calcium is absent in the extracellular environment, while TG2 inhibitors do not restore the full aggregating potential of gluten in the presence of calcium. These findings suggest that TG2 activity is not essential in the cellular aggregation mechanism. We demonstrate that gluten contacts the cells and provokes their aggregation through a mechanism involving the A-gliadin peptide 31-43. This peptide also activates the cell surface associated extracellular TG2 in the absence of calcium. Using a bioinformatics approach, we identify the possible docking sites of this peptide on the open and closed TG2 structures. Peptide docks with the closed TG2 structure near to the GTP/GDP site, by establishing molecular interactions with the same amino acids involved in stabilization of GTP binding. We suggest that it may occur through the displacement of GTP, switching the TG2 structure from the closed to the active open conformation. Furthermore, docking analysis shows peptide binding with the β-sandwich domain of the closed TG2 structure, suggesting that this region could be responsible for the different aggregating effects of gluten shown in the presence or absence of calcium. We deduce from these data a possible mechanism of action by which gluten makes contact with the cell surface, which could have possible implications in the celiac disease onset.

AB - Gluten-induced aggregation of K562 cells represents an in vitro model reproducing the early steps occurring in the small bowel of celiac patients exposed to gliadin. Despite the clear involvement of TG2 in the activation of the antigen-presenting cells, it is not yet clear in which compartment it occurs. Herein we study the calcium-dependent aggregation of these cells, using either cell-permeable or cell-impermeable TG2 inhibitors. Gluten induces efficient aggregation when calcium is absent in the extracellular environment, while TG2 inhibitors do not restore the full aggregating potential of gluten in the presence of calcium. These findings suggest that TG2 activity is not essential in the cellular aggregation mechanism. We demonstrate that gluten contacts the cells and provokes their aggregation through a mechanism involving the A-gliadin peptide 31-43. This peptide also activates the cell surface associated extracellular TG2 in the absence of calcium. Using a bioinformatics approach, we identify the possible docking sites of this peptide on the open and closed TG2 structures. Peptide docks with the closed TG2 structure near to the GTP/GDP site, by establishing molecular interactions with the same amino acids involved in stabilization of GTP binding. We suggest that it may occur through the displacement of GTP, switching the TG2 structure from the closed to the active open conformation. Furthermore, docking analysis shows peptide binding with the β-sandwich domain of the closed TG2 structure, suggesting that this region could be responsible for the different aggregating effects of gluten shown in the presence or absence of calcium. We deduce from these data a possible mechanism of action by which gluten makes contact with the cell surface, which could have possible implications in the celiac disease onset.

KW - agglutination

KW - gluten

KW - K562 cells

KW - TG2

KW - TG2-inhibitors

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DO - 10.1007/s00726-016-2339-4

M3 - Article

VL - In press

JO - Amino Acids

T2 - Amino Acids

JF - Amino Acids

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