Neural precursor cell–secreted TGF-β2 redirects inflammatory monocyte-derived cells in CNS autoimmunity
Donatella De Feo, … , Melanie Greter, Gianvito Martino
Donatella De Feo, … , Melanie Greter, Gianvito Martino
Published September 25, 2017
Citation Information: J Clin Invest. 2017;127(11):3937-3953. https://doi.org/10.1172/JCI92387.
View: Text | PDF
Research Article Autoimmunity

Neural precursor cell–secreted TGF-β2 redirects inflammatory monocyte-derived cells in CNS autoimmunity

Abstract

In multiple sclerosis, the pathological interaction between autoreactive Th cells and mononuclear phagocytes in the CNS drives initiation and maintenance of chronic neuroinflammation. Here, we found that intrathecal transplantation of neural stem/precursor cells (NPCs) in mice with experimental autoimmune encephalomyelitis (EAE) impairs the accumulation of inflammatory monocyte-derived cells (MCs) in the CNS, leading to improved clinical outcome. Secretion of IL-23, IL-1, and TNF-α, the cytokines required for terminal differentiation of Th cells, decreased in the CNS of NPC-treated mice, consequently inhibiting the induction of GM-CSF–producing pathogenic Th cells. In vivo and in vitro transcriptome analyses showed that NPC-secreted factors inhibit MC differentiation and activation, favoring the switch toward an antiinflammatory phenotype. Tgfb2–/– NPCs transplanted into EAE mice were ineffective in impairing MC accumulation within the CNS and failed to drive clinical improvement. Moreover, intrathecal delivery of TGF-β2 during the effector phase of EAE ameliorated disease severity. Taken together, these observations identify TGF-β2 as the crucial mediator of NPC immunomodulation. This study provides evidence that intrathecally transplanted NPCs interfere with the CNS-restricted inflammation of EAE by reprogramming infiltrating MCs into antiinflammatory myeloid cells via secretion of TGF-β2.

Authors

Donatella De Feo, Arianna Merlini, Elena Brambilla, Linda Ottoboni, Cecilia Laterza, Ramesh Menon, Sundararajan Srinivasan, Cinthia Farina, Jose Manuel Garcia Manteiga, Erica Butti, Marco Bacigaluppi, Giancarlo Comi, Melanie Greter, Gianvito Martino

×

Figure 10

NPCs inhibit BMDC maturation in vitro via TGF-β2.

Options: View larger image (or click on image) Download as PowerPoint
NPCs inhibit BMDC maturation in vitro via TGF-β2. (A) Color-coded expres...
(A) Color-coded expression heatmap of selected TGF-β family growth factors and TGF-β activating enzymes in NPCs (left) and of their relative receptors on mDC (CD40L-stimulated BMDCs; right). Data are represented as ΔCt over Gapdh (note that a higher ΔCt denotes a lower expression level). (B) ELISA for TGF-β2 performed on NCM from NPCs cultured in DC medium for 2, 6, 24, and 48 hours. (C) Quantification by ELISA of IL23p19 secreted in the supernatant of mDC cultured either in control medium (black bar) or in the presence of recombinant TGF-β2 at increasing concentrations (gray bars). (D and E) Quantification by ELISA of IL23p19 secreted by mDC cultured either in NCM alone (white bar) or in the presence of the TGFBRI tyrosine kinase inhibitor SB431542 (gray bars) (D) or with the TGFBRII inhibitor ITD1 (gray bar) (E). (F) Quantification by ELISA of the IL23p19 secreted by mDC from control littermates CD11c-Cre+Tgfbr2WT/WT (white bar) and CD11c-Cre–Tgfbr2fl/fl (gray bar) versus CD11c-Cre+Tgfbr2fl/fl (gray striped bar) mDC lacking TGFBRII in CD11c+ cells. Data in D-F are fold induction (FI) relative to mDC matured in control medium subjected to the same treatment. (G) Expression of Tgfb2 mRNA in WT (Tgfb2+/+), Tgfb2+/–, and Tgfb2–/– eNPCs cultured for 48 hours in DCM relative to WT NPCs. (H) TGF-β2 protein quantification by ELISA secreted by Tgfb2+/+, Tgfb2+/–, and Tgfb2–/– eNPCs cultured for 48 hours in DC medium. (I) IL23p19 production (measured by ELISA) by mDC cultured in NCM from Tgfb2+/+ (white bar) and Tgfb2–/– (gray bar) eNPCs. Data are FI relative to mDC matured in control medium. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001, 1-way ANOVA with Bonferroni’s post-test (C, D, F, H, and I); *P ≤ 0.05, **P ≤ 0.01, ****P ≤ 0.0001, unpaired t test (E, G). Data are mean ± SEM and are representative of at least 2 independent experiments.