Retrograde interferon‐gamma signaling induces major histocompatibility class I expression in human‐induced pluripotent stem cell‐derived neurons
BDS Clarkson, MS Patel… - Annals of Clinical …, 2018 - Wiley Online Library
BDS Clarkson, MS Patel, RG LaFrance‐Corey, CL Howe
Annals of Clinical and Translational Neurology, 2018•Wiley Online LibraryObjective Injury‐associated axon‐intrinsic signals are thought to underlie pathogenesis and
progression in many neuroinflammatory and neurodegenerative diseases, including
multiple sclerosis (MS). Retrograde interferon gamma (IFN γ) signals are known to induce
expression of major histocompatibility class I (MHC I) genes in murine axons, thereby
increasing the susceptibility of these axons to attack by antigen‐specific CD 8+ T cells. We
sought to determine whether the same is true in human neurons. Methods A novel …
progression in many neuroinflammatory and neurodegenerative diseases, including
multiple sclerosis (MS). Retrograde interferon gamma (IFN γ) signals are known to induce
expression of major histocompatibility class I (MHC I) genes in murine axons, thereby
increasing the susceptibility of these axons to attack by antigen‐specific CD 8+ T cells. We
sought to determine whether the same is true in human neurons. Methods A novel …
Objective
Injury‐associated axon‐intrinsic signals are thought to underlie pathogenesis and progression in many neuroinflammatory and neurodegenerative diseases, including multiple sclerosis (MS). Retrograde interferon gamma (IFNγ) signals are known to induce expression of major histocompatibility class I (MHC I) genes in murine axons, thereby increasing the susceptibility of these axons to attack by antigen‐specific CD8+ T cells. We sought to determine whether the same is true in human neurons.
Methods
A novel microisolation chamber design was used to physically isolate and manipulate axons from human skin fibroblast‐derived induced pluripotent stem cell (iPSC)‐derived neuron‐enriched neural aggregates. Fluorescent retrobeads were used to assess the fraction of neurons with projections to the distal chamber. Axons were treated with IFNγ for 72 h and expression of MHC class I and antigen presentation genes were evaluated by RT‐PCR and immunofluorescence.
Results
Human iPSC‐derived neural stem cells maintained as 3D aggregate cultures in the cell body chamber of polymer microisolation chambers extended dense axonal projections into the fluidically isolated distal chamber. Treatment of these axons with IFNγ resulted in upregulation of MHC class I and antigen processing genes in the neuron cell bodies. IFNγ‐induced MHC class I molecules were also anterogradely transported into the distal axon.
Interpretation
These results provide conclusive evidence that human axons are competent to express MHC class I molecules, suggesting that inflammatory factors enriched in demyelinated lesions may render axons vulnerable to attack by autoreactive CD8+ T cells in patients with MS. Future work will be aimed at identifying pathogenic anti‐axonal T cells in these patients.
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