scholarly journals Interleukin-19 alleviates experimental autoimmune encephalomyelitis by attenuating antigen-presenting cell activation

2020 ◽  
Author(s):  
Hiroshi Horiuchi ◽  
Bijay Parajuli ◽  
Hiroyasu Komiya ◽  
Yuki Ogawa ◽  
Jin Shijie ◽  
...  

AbstractInterleukin-19 (IL-19) acts as an anti-inflammatory cytokine in various inflammatory diseases. Multiple sclerosis (MS) is a major neuroinflammatory disease in the central nervous system, but it remains uncertain how IL-19 contributes to MS pathogenesis. Here, we demonstrate that IL-19 deficiency aggravates experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by promoting IL-17–producing helper T cell (Th17 cell) infiltration into the central nervous system. In addition, IL-19–deficient splenic macrophages expressed elevated levels of major histocompatibility complex class II, co-stimulatory molecules, and Th17 cell differentiation–associated cytokines such as IL-1β, IL-6, IL-23, TGF-β1, and TNF-α. These observations indicated that IL-19 plays a critical role in suppression of MS pathogenesis by inhibiting macrophage antigen presentation, Th17 cell expansion, and subsequent inflammatory responses. Furthermore, treatment with IL-19 significantly abrogated EAE. Our data suggest that IL-19 could provide significant therapeutic benefits in patients with MS.

2021 ◽  
Vol 12 ◽  
Author(s):  
Hiroshi Horiuchi ◽  
Bijay Parajuli ◽  
Hiroyasu Komiya ◽  
Yuki Ogawa ◽  
Shijie Jin ◽  
...  

Interleukin-19 (IL-19) acts as a negative-feedback regulator to limit proinflammatory response of macrophages and microglia in autocrine/paracrine manners in various inflammatory diseases. Multiple sclerosis (MS) is a major neuroinflammatory disease in the central nervous system (CNS), but it remains uncertain how IL-19 contributes to MS pathogenesis. Here, we demonstrate that IL-19 deficiency aggravates experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by promoting IL-17-producing helper T cell (Th17 cell) infiltration into the CNS. In addition, IL-19-deficient splenic macrophages expressed elevated levels of major histocompatibility complex (MHC) class II, co-stimulatory molecules, and Th17 cell differentiation-associated cytokines such as IL-1β, IL-6, IL-23, TGF-β1, and TNF-α. These observations indicated that IL-19 plays a critical role in suppression of MS pathogenesis by inhibiting macrophage antigen presentation, Th17 cell expansion, and subsequent inflammatory responses. Furthermore, treatment with IL-19 significantly abrogated EAE. Our data suggest that IL-19 could provide significant therapeutic benefits in patients with MS.


2021 ◽  
Author(s):  
William E. Barclay ◽  
M. Elizabeth Deerhake ◽  
Makoto Inoue ◽  
Toshiaki Nonaka ◽  
Kengo Nozaki ◽  
...  

ABSTRACTInflammasomes are a class of innate immune signaling platforms that activate in response to an array of cellular damage and pathogens. Inflammasomes promote inflammation under many circumstances to enhance immunity against pathogens and inflammatory responses through their effector cytokines, IL-1β and IL-18. Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are such autoimmune conditions influenced by inflammasomes. Despite work investigating inflammasomes during EAE, little remains known concerning the role of inflammasomes in the central nervous system (CNS) during the disease. Here we use multiple genetically modified mouse models to monitor activated inflammasomes in situ based on ASC oligomerization in the spinal cord. Using inflammasome reporter mice, we found heightened inflammasome activation in astrocytes after the disease peak. In contrast, microglia and CNS-infiltrated myeloid cells had few activated inflammasomes in the CNS during EAE. Astrocyte inflammasome activation was dependent on AIM2, but low IL-1β expression and no significant signs of cell death were found in astrocytes during EAE. Thus, the AIM2 inflammasome activation in astrocytes may have a distinct role from traditional inflammasome-mediated inflammation.SIGNIFICANCE STATEMENTInflammasome activation in the peripheral immune system is pathogenic in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). However, inflammasome activity in the central nervous system (CNS) is largely unexplored. Here, we used genetically modified mice to determine inflammasome activation in the CNS during EAE. Our data indicated heightened AIM2 inflammasome activation in astrocytes after the disease peak. Unexpectedly, neither CNS-infiltrated myeloid cells nor microglia were the primary cells with activated inflammasomes in SC during EAE. Despite AIM2 inflammasome activation, astrocytes did not undergo apparent cell death and produced little of the proinflammatory cytokine, IL-1β, during EAE. This study showed that CNS inflammasome activation occurs during EAE without associating with IL-1β-mediated inflammation.


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