Impact of a Demyelination-Inducing CNS Virus on Expression of Demyelination Genes in Type 2 Lymphoid Cells (ILC2s)

We recently reported the role of innate lymphoid cells type 2 (ILC2s) in CNS demyelination using an HSV-IL-2 model of CNS demyelination. Here we studied how ILC2s respond to HSV-IL-2 at the cellular level using cytokine and gene expression profiling. ILC2s infected with HSV-IL-2 expressed higher levels of GM-CSF, IL-5, IL-6, IL-13, IP-10, MIP-2, and RANTES, which include proinflammatory cytokines, than did those infected with parental control virus. In contrast, TH2 cytokines IL-4 and IL-9, which are typically expressed by ILC2s, were not induced upon HSV-IL-2 infection. RNA-Seq analysis of HSV-IL-2 infected ILC2s showed significant upregulation of over 350 genes and downregulation of 157 genes compared with parental virus-infected ILC2s. GO term analysis indicated that genes related to “mitosis” and “inflammatory response” were among the upregulated genes, suggesting that HSV-IL-2 infection drives the excessive proliferation and atypical inflammatory response of ILC2s. This change in ILC2 activation state could underlie the pathology of demyelinating diseases. IMPORTANCE Innate lymphocytes have plasticity and can change functionality; innate lymphoid cells type 2 (ILC2s) can convert to ILC1 or ILC3 cells, or change their activation state to produce IL-17 or IL-10 depending on environmental cues. In this study, we investigated the gene and cytokine profile of ILC2s, which play a major role in HSV-IL-2-induced CNS demyelination. ILC2s infected with HSV-IL-2 displayed a massive remodeling of cellular state. Additionally, ILC2s infected with HSV-IL-2 differed from those infected with parental HSV in cellular and viral gene expression profiles and in cytokine/chemokine induction, and displayed enhanced activation and proinflammatory responses. These changes in ILC2 activation state could underlie the pathology of demyelinating diseases. These results also highlight the possible importance of pathogens as environmental cues to modify innate lymphocyte functionalities.

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Group 2 Innate Lymphoid Cells: Central Players in a Recurring Theme of Repair and Regeneration

International Journal of Molecular Sciences ◽

10.3390/ijms21041350 ◽

2020 ◽

Vol 21 (4) ◽

pp. 1350 ◽

Cited By ~ 3

Author(s):

Melina Messing ◽

Sia Cecilia Jan-Abu ◽

Kelly McNagny

Keyword(s):

T Regulatory Cells ◽

Inflammatory Responses ◽

Expression Profiles ◽

Innate Lymphoid Cells ◽

Lymphoid Cells ◽

Helminth Infections ◽

Neonatal Immunity ◽

Group 2 ◽

Transcription Factor Expression

Innate lymphoid cells (ILCs) are recently discovered innate counterparts to the well-established T helper cell subsets and are most abundant at barrier surfaces, where they participate in tissue homeostasis and inflammatory responses against invading pathogens. Group 2 innate lymphoid cells (ILC2s) share cytokine and transcription factor expression profiles with type-2 helper T cells and are primarily associated with immune responses against allergens and helminth infections. Emerging data, however, suggests that ILC2s are also key regulators in other inflammatory settings; both in a beneficial context, such as the establishment of neonatal immunity, tissue repair, and homeostasis, and in the context of pathological tissue damage and disease, such as fibrosis development. This review focuses on the interactions of ILC2s with stromal cells, eosinophils, macrophages, and T regulatory cells that are common to the different settings in which type-2 immunity has been explored. We further discuss how an understanding of these interactions can reveal new avenues of therapeutic tissue regeneration, where the role of ILC2s is yet to be fully established.

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