The inflammatory transcriptome of reactive murine astrocytes and implications for their innate immune function

Abstract

Upon injury, astrocytes assume an activated state associated with the release of inflammatory mediators. To model this, we stimulated murine primary astrocytes with a complete inflammatory cytokine mix consisting of TNF-a, IL-1b and IFN-c. We analysed the transcriptional response of 480 genes at 4 and 16 h after stimulation on a chip designed to give a representative overview over the inflammation-relevant part of the transcriptome of macrophage-like cells. The list of the 182 genes found to be significantly regulated in astrocytes revealed an intriguing co-ordinate regulation of genes linked to the biological processes of antiviral/antimicrobial defence, antigen presentation and facilitation of leucocyte invasion. The latter group was characterized by very high up-regulations of chemokine genes. We also identified regulations of a thymidylate kinase and an interferon-regulated protein with a tetratricopeptide motive, both up to now only known from macrophages. The transcriptional regulations were confirmed on the protein level by a proteomic analysis. These findings taken together suggest that activated astrocytes in brain behave similarly in many respects to inflamed macrophages in the periphery.

Switching from astrocytic neuroprotection to neurodegeneration by cytokine stimulation

“…To model an inflammatory situation, as it occurs during brain damage and neurodegenerative disease, we used a cytokine mix (TNF-α and IL-1β) known to be produced in neuroinflammatory situations (mainly by microglia) and known to activate astrocytic cells, including IMA (Falsig et al 2006;Henn et al 2011;Kuegler et al 2012;Schildknecht et al 2012). This CM had no effect on the viability and neurite structure of LUHMES monocultures (Fig.…”

Adverse Outcome Pathway on binding of agonists to ionotropic glutamate receptors in adult brain leading to excitotoxicity that mediates neuronal cell death, contributing to learning and memory impairment

“…The M2 state is triggered by IL-4 and IL-13 (Maresz et al, 2008;Perego et al, 2011;Ponomarev et al, 2007) and induces the expression of mannose receptor 1 (MRC1), arginase1 (Arg 1) and Ym1/2; it is involved in repair processes. The activation of astrocytes by microglia-derived cytokines or TLR agonists resembles the microglial M1 state (Falsig, 2006).…”

Proteomic strategies in multiple sclerosis and its animal models

“…Four of these proteins were associated with the actin cytoskeleton. In a second study, Falsig et al [129] analyzed both protein and transcript levels of mouse astrocytes exposed to a mixture of inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), and interferon-γ (IFN-γ). The abundance of proteins in controls versus activated astrocytes was assessed by silver staining of 2-D gels and by labeling of lysates obtained from controls and activated astocytes with two different isotopes.…”

“…About 28% of proteins were represented on the gels by multiple spots indicating PTM. Three additional investigations used proteomic approaches to identify proteins which are modulated in activated astrocytes, in vitro [127][128][129]. In one of the studies [127], rat astrocytes were exposed to endothelin-1, a stimulus implicated in CNS injury and stroke.…”

“…A number of studies have used proteomic approaches to create a databank of proteins expressed in astrocytes [125,126] or delineate their differential regulation upon activation of cells [127][128][129].…”