A novel regulation of PD-1 ligands on mesenchymal stromal cells through MMP-mediated proteolytic cleavage

• Published in: Oncoimmunology Vol. 5; no. 3; p. e1091146
• Main Authors: Dezutter-Dambuyant, Colette, Durand, Isabelle, Alberti, Laurent, Bendriss-Vermare, Nathalie, Valladeau-Guilemond, Jenny, Duc, Adeline, Magron, Audrey, Morel, Anne-Pierre, Sisirak, Vanja, Rodriguez, Céline, Cox, David, Olive, Daniel, Caux, Christophe
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 03.03.2016
• Subjects: Apoptosis; fibroblasts; immunosuppression; Life Sciences; MMP-13; Original Research; PD-L1; PD-L2; PD1; fibroblasts; MMP-13; PD-L1; PD-L2; immunosuppression; PD1; Apoptosis; Extra-Cellular Matrix; PS; Mesenchymal Stem Cell; PFA; p-AminoPhenyl-Mercuric Acetate; Programmed Death-Ligand 2; MDC; sPD-L1; ddPCR; recombinant human; ADAM; Gy; natural killer; Programmed Death-Ligand 1; SA-b-gal; IFNg; infant Foreskin Fibroblasts; InterLeukin-10; PhosphatidylSerine; InterLeukin-1 a; Mo-DC; PhytoHemAglutinin; IL-1a; APMA; PBS; Gray; interferon gamma; TGFb; CLSPA; Mean Fluorescence Intensity; BM-MSC; myeloid Dendritic Cell; ParaFormAldehyde; soluble PD-L1 form; IL-10; MMP; 30 Gray-irradiated infant Foreskin Fibroblast; InterLeukin-6 Receptor; 30-Gray irradiation Apoptosis; droplet digital PCR; rh; FCS; senescence-associated b-galactosidase; Dendritic Cell; Monocyte-derived dendritic cell; NK; PD-1; Foetal Calf Serum; FF; InterLeukin-17 A; Transforming Growth Factor b; PHA; g-FF; Bone Marrow-derived Mesenchymal Stem Cell; A Disintegrin And Metalloproteinase; EGFR; MFI; Antigen-Presenting Cell; Epidermal Growth Factor Receptor; MSC; IL-6R; monoclonal Antibody; IL-17A; CFSE; Proliferation Index; ECM; mAb; Programmed cell Death protein-1; Tumor Necrosis Factor a; TNFa; APC; CarboxyFluorescein Succinimidyl Ester; Phosphate-Buffered Saline; PI; g-irradiation; Chromatographically purified collagenase; Matrix MetalloProteinase; DC
• ISSN: 2162-4011; 2162-402X; 2162-402X
• DOI: 10.1080/2162402X.2015.1091146

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 + 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 + 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.