TY - JOUR
T1 - CNS-specific immunity at the choroid plexus shifts toward destructive Th2 inflammation in brain aging
AU - Baruch, Kuti
AU - Ron-Harel, Noga
AU - Gal, Hilah
AU - Deczkowska, Aleksandra
AU - Shifrut, Eric
AU - Ndifon, Wilfred
AU - Mirlas-Neisberg, Nataly
AU - Cardon, Michal
AU - Vaknin, Ilan
AU - Cahalon, Liora
AU - Berkutzki, Tamara
AU - Mattson, Mark P.
AU - Gomez-Pinilla, Fernando
AU - Friedman, Nir
AU - Schwartz, Michal
PY - 2013/2/5
Y1 - 2013/2/5
N2 - The adaptive arm of the immune system has been suggested as an important factor in brain function. However, given the fact that interactions of neurons or glial cells with T lymphocytes rarely occur within the healthy CNS parenchyma, the underlying mechanism is still a mystery. Here we found that at the interface between the brain and blood circulation, the epithelial layers of the choroid plexus (CP) are constitutively populated with CD4+ effector memory cells with a T-cell receptor repertoire specific to CNS antigens. With age, whereas CNS specificity in this compartment was largely maintained, the cytokine balance shifted in favor of the T helper type 2 (Th2) response; the Th2-derived cytokine IL-4 was elevated in the CP of old mice, relative to IFN-γ, which decreased. We found this local cytokine shift to critically affect the CP epithelium, triggering it to produce the chemokine CCL11 shown to be associated with cognitive dysfunction. Partial restoration of cognitive ability in aged mice, by lymphopenia-induced homeostasis-driven proliferation of memory T cells, was correlated with restoration of the IL-4:IFN-γ ratio at the CP and modulated the expression of plasticity-related genes at the hippocampus. Our data indicate that the cytokine milieu at the CP epithelium is affected by peripheral immunosenescence, with detrimental consequences to the aged brain. Amenable to immunomodulation, this interface is a unique target for arresting age-related cognitive decline.
AB - The adaptive arm of the immune system has been suggested as an important factor in brain function. However, given the fact that interactions of neurons or glial cells with T lymphocytes rarely occur within the healthy CNS parenchyma, the underlying mechanism is still a mystery. Here we found that at the interface between the brain and blood circulation, the epithelial layers of the choroid plexus (CP) are constitutively populated with CD4+ effector memory cells with a T-cell receptor repertoire specific to CNS antigens. With age, whereas CNS specificity in this compartment was largely maintained, the cytokine balance shifted in favor of the T helper type 2 (Th2) response; the Th2-derived cytokine IL-4 was elevated in the CP of old mice, relative to IFN-γ, which decreased. We found this local cytokine shift to critically affect the CP epithelium, triggering it to produce the chemokine CCL11 shown to be associated with cognitive dysfunction. Partial restoration of cognitive ability in aged mice, by lymphopenia-induced homeostasis-driven proliferation of memory T cells, was correlated with restoration of the IL-4:IFN-γ ratio at the CP and modulated the expression of plasticity-related genes at the hippocampus. Our data indicate that the cytokine milieu at the CP epithelium is affected by peripheral immunosenescence, with detrimental consequences to the aged brain. Amenable to immunomodulation, this interface is a unique target for arresting age-related cognitive decline.
KW - Blood-cerebrospinal fluid barrier
KW - Brain senescence
KW - Neuroinflammation
UR - http://www.scopus.com/inward/record.url?scp=84873475219&partnerID=8YFLogxK
U2 - 10.1073/pnas.1211270110
DO - 10.1073/pnas.1211270110
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C2 - 23335631
AN - SCOPUS:84873475219
SN - 0027-8424
VL - 110
SP - 2264
EP - 2269
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 6
ER -