Gene Regulatory Network of Human GM-CSF-Secreting T Helper Cells

Translating the biology of β common receptor-engaging cytokines into clinical medicine

The family of cytokines that comprises IL-3, IL-5, and GM-CSF was discovered over 30 years ago, and their biological activities and resulting impact in clinical medicine has continued to expand ever since. Originally identified as bone marrow growth factors capable of acting on hemopoietic progenitor cells to induce their proliferation and differentiation into mature blood cells, these cytokines are also recognized as key mediators of inflammation and the pathobiology of diverse immunologic diseases. This increased understanding of the functional repertoire of IL-3, IL-5, and GM-CSF has led to an explosion of interest in modulating their functions for clinical management. Key to the successful clinical translation of this knowledge is the recognition that these cytokines act by engaging distinct dimeric receptors and that they share a common signaling subunit called β-common or βc. The structural determination of how IL-3, IL-5, and GM-CSF interact with their receptors and linking this to their differential biological functions on effector cells has unveiled new paradigms of cell signaling. This knowledge has paved the way for novel mAbs and other molecules as selective or pan inhibitors for use in different clinical settings.

Granulocyte-macrophage colony-stimulating factor suppresses induction of type I interferon in infants with severe pneumonia

BACKGROUND

The underlying mechanisms for infantile bronchopneumonia development remain unknown.

METHODS

Peripheral blood mononuclear cell (PBMCs) and serum derived from severe and mild infantile bronchopneumonia were obtained, and the expression of various molecules was detected with enzyme-linked immunosorbent assay and quantitative PCR. Such molecules were also detected in granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced bone marrow-derived NFκB2^-/- dendritic cells (DCs) or NIK SMI1 (NF-κB-inducing kinase inhibitor) administrated DCs.

RESULTS

The relative mRNA expression levels of type I interferons (IFNs) (IFN-α4, IFN-β), Th17 cell-associated markers (interleukin-17A, retinoic-acid-receptor-related orphan nuclear receptor gamma, and GM-CSF), and non-canonical NF-κB member (NFκB2) were significantly up-regulated in PBMCs and DCs derived from infantile bronchopneumonia compared with healthy controls. However, compared with Th17 cell-associated markers and non-canonical NF-κB molecules, the expression of IFN-α4 and IFN-β was significantly inhibited in severe infantile bronchopneumonia compared with mild infantile bronchopneumonia. The relative protein expression of the above molecules also showed a similar expression pattern in the PBMCs or serum. NF-κB2 knockout or NIK SMI1 administration could reverse the diminished expression of IFN-β in GM-CSF-induced bone marrow-derived DCs.

CONCLUSIONS

GM-CSF-dependent non-canonical NF-κB pathway-mediated inhibition of type I IFNs production in DCs contributes to the development of severe bronchopneumonia in infant.

IMPACT

Granulocyte-macrophage colony-stimulating factor-dependent non-canonical NF-κB pathway-mediated inhibition of type I IFNs production in dendritic cells is critical for the development of infantile bronchopneumonia. Our findings reveal a possible mechanism underlying the development of severe infantile bronchopneumonia. The results could provide therapeutic molecular target for the treatment of such disease.