A novel regulation of PD-1 ligands on mesenchymal stromal cells through MMP-mediated proteolytic cleavage
Résumé
Whether fibroblasts regulate immune response is a crucial issue in the modulation of inflammatory responses. Herein, we demonstrate that foreskin fibroblasts (FFs) potently inhibit CD3 C T cell proliferation through a mechanism involving early apoptosis of activated T cells. Using blocking antibodies, we demonstrate that the inhibition of T cell proliferation occurs through cell-to-cell interactions implicating PD-1 receptor expressed on T cells and its ligands, PD-L1 and PD-L2, on fibroblasts. Dual PD-1 ligand neutralization is required to abrogate (i) binding of the PD-1-Fc fusion protein, (ii) early apoptosis of T cells, and (iii) inhibition of T cell proliferation. Of utmost importance, we provide the first evidence that PD-1 ligand expression is regulated through proteolytic cleavage by endogenous matrix metalloproteinases (MMPs) without transcriptional alteration during culture-time. Using (i) different purified enzymatic activities, (ii) MMP-specific inhibitors, and (iii) recombinant human MMP-9 and MMP-13, we demonstrated that in contrast to CD80/CD86, PD-L1 was selectively cleaved by MMP-13, while PD-L2 was sensitive to broader MMP activities. Their cleavage by exogenous MMP-9 and MMP-13 with loss of PD-1 binding domain resulted in the reversion of apoptotic signals on mitogen-activated CD3 C T cells. We suggest that MMP-dependent cleavage of PD-1 ligands on fibroblasts may limit their immunosuppressive capacity and thus contribute to the exacerbation of inflammation in tissues. In contrast, carcinoma-associated fibroblasts appear PD-1 ligand-depleted through MMP activity that may impair physical deletion of exhausted defective memory T cells through apoptosis and facilitate their regulatory functions. These observations should be considered when using the powerful PD-1/PD-L1 blocking immunotherapies.
Mots clés
Epidermal Growth Factor Receptor
FCS
Foetal Calf Serum
FF
infant Foreskin Fibroblasts
Gy
Gray
IFNg
interferon gamma
IL-10
InterLeukin-10
IL-17A
InterLeukin-17 A
IL-1a
InterLeukin-1 a
IL-6R
InterLeukin-6 Receptor
mAb
monoclonal Antibody
MDC
myeloid Dendritic Cell
MFI
Mean Fluorescence Intensity
MMP
Matrix MetalloProteinase
Mo-DC
Monocyte-derived dendritic cell
MSC
Mesenchymal Stem Cell
NK
natural killer
PBS
Phosphate-Buffered Saline
PD-1
Programmed cell Death protein-1
PD-L1
Programmed Death-Ligand 1
PD-L2
Programmed Death-Ligand 2
PFA
ParaFormAldehyde
PHA
PhytoHemAglutinin
PI
Proliferation Index
PS
PhosphatidylSerine
rh
recombinant human
SA-b-gal
senescence-associated b-galactosidase
sPD-L1
soluble PD-L1 form
TGFb
Transforming Growth Factor b
TNFa
Tumor Necrosis Factor a
g-FF
30 Gray-irradiated infant Foreskin Fibroblast
g-irradiation
30-Gray irradiation Apoptosis
fibroblasts
immunosuppression
MMP-13
PD1
ADAM
A Disintegrin And Metalloproteinase
APC
Antigen-Presenting Cell
APMA
p-AminoPhenyl-Mercuric Acetate
BM-MSC
Bone Marrow-derived Mesenchymal Stem Cell
CFSE
CarboxyFluorescein Succinimidyl Ester
CLSPA
Chromatographically purified collagenase
DC
Dendritic Cell
ddPCR
droplet digital PCR
ECM
Extra-Cellular Matrix
EGFR
Domaines
Sciences du Vivant [q-bio]
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