Upregulation of NKG2D ligands impairs hematopoietic stem cell function in Fanconi anemia
José A. Casado, … , Paula Rio, Juan A. Bueren
José A. Casado, … , Paula Rio, Juan A. Bueren
Published June 7, 2022
Citation Information: J Clin Invest. 2022;132(15):e142842. https://doi.org/10.1172/JCI142842.
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Research Article Immunology

Upregulation of NKG2D ligands impairs hematopoietic stem cell function in Fanconi anemia

Abstract

Fanconi anemia (FA) is the most prevalent inherited bone marrow failure (BMF) syndrome. Nevertheless, the pathophysiological mechanisms of BMF in FA have not been fully elucidated. Since FA cells are defective in DNA repair, we hypothesized that FA hematopoietic stem and progenitor cells (HSPCs) might express DNA damage–associated stress molecules such as natural killer group 2 member D ligands (NKG2D-Ls). These ligands could then interact with the activating NKG2D receptor expressed in cytotoxic NK or CD8+ T cells, which may result in progressive HSPC depletion. Our results indeed demonstrated upregulated levels of NKG2D-Ls in cultured FA fibroblasts and T cells, and these levels were further exacerbated by mitomycin C or formaldehyde. Notably, a high proportion of BM CD34+ HSPCs from patients with FA also expressed increased levels of NKG2D-Ls, which correlated inversely with the percentage of CD34+ cells in BM. Remarkably, the reduced clonogenic potential characteristic of FA HSPCs was improved by blocking NKG2D–NKG2D-L interactions. Moreover, the in vivo blockage of these interactions in a BMF FA mouse model ameliorated the anemia in these animals. Our study demonstrates the involvement of NKG2D–NKG2D-L interactions in FA HSPC functionality, suggesting an unexpected role of the immune system in the progressive BMF that is characteristic of FA.

Authors

José A. Casado, Antonio Valeri, Rebeca Sanchez-Domínguez, Paula Vela, Andrea López, Susana Navarro, Omaira Alberquilla, Helmut Hanenberg, Roser Pujol, José-Carlos Segovia, Jordi Minguillón, Jordi Surrallés, Cristina Díaz de Heredia, Julián Sevilla, Paula Rio, Juan A. Bueren

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Figure 2

Comparative analysis of NKG2D-L levels in uncorrected and gene-corrected T cells from patients with FA-A and HDs.

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Comparative analysis of NKG2D-L levels in uncorrected and gene-corrected...
(A) Comparative analysis of NKG2D-Ls in in vitro–cultured T cells from HDs (n = 9) and patients with FA-A (n = 6). Mononuclear PB cells from HDs and patients with FA-A were stimulated with anti-CD3 and anti-CD28 mAbs for 4 days and analyzed for NKG2D-L expression. The figure shows the ratio of the MFI after staining with NKG2D-L antibodies with respect to the basal fluorescence level. (B) Fold increase of NKG2D-L levels in MMC-treated (33 nM or 100 nM) versus untreated T cells from HDs (n = 12, 33 nM and n = 10, 100 nM) and patients with FA-A (n = 8, 33 nM and n = 6, 100 nM). NKG2D-L MFI ratios between MMC-treated and untreated cells are shown. (C) Analysis of MMC-induced (33 nM) expression of NKG2D-L in uncorrected (+FANCG) and corrected (+FANCA) T cells from 3 patients with FA-A. Flow cytometric histograms show representative NKG2D-L analyses in HD and FA-A T cells transduced with the FANCA or FANCG vector. Data in A–C represent the mean ± SEM. In A and B, differences between HD and FA cells were assessed by unpaired t test. In C, differences between corrected and uncorrected samples were evaluated using a paired t test.