Strawberry notch homolog 2 is a novel nuclear IL-6 primary response gene in glial cells — ASN Events
  1. Schedule
  2. Poster Session 2
  3. Strawberry notch homolog 2 is a novel nuclear IL-6 primary response gene in glial cells

Strawberry notch homolog 2 is a novel nuclear IL-6 primary response gene in glial cells (#334)

Taylor E Syme 1 , Magdalena Grill 1 , Stefan Rose-John 2 , Iain L Campbell 1
  1. School of Molecular Bioscience & Bosch Institute, University of Sydney, Sydney, NSW, Australia
  2. Department of Biochemistry, University of Kiel, Kiel, Germany

Aims: An investigation of potential transcriptional mechanisms underlying interleukin (IL)-6 actions identified a novel putative murine transcriptional regulator called strawberry notch homolog 2 (Sbno2) as a prominent IL-6 target gene. We hypothesise that Sbno2 is a key regulator of IL-6 and other gp130 family cytokine actions in the CNS and other tissues. The aim of this study was to better define the hyper-IL-6-induced regulation of Sbno2 in astrocytes and microglia, as well as to examine its localisation using lentiviral transduction.

Methods: Murine primary cultured astrocytes and the C8-B4 microglial cell line were treated with 25 ng/mL hyper-IL-6 and 10 µg/mL cycloheximide, and astrocytes were treated with 25 ng/mL hyper-IL-6 and 10 µg/mL actinomycin D. To determine SBNO2 localisation, lentiviral vectors were produced to deliver an HA epitope-tagged Sbno2 gene and a bicistronic fluorescent marker into the NIH-3T3 murine fibroblast cell line. Fluorescence immunocytochemistry was performed using an antibody against the HA epitope to visualise the transgenic SBNO2.

Results: Treatment with the protein synthesis inhibitor cycloheximide alone had little to no effect, but superinduced Sbno2 expression over 8-fold upon hyper-IL-6 treatment in both cell types. Previous results showed that hyper-IL-6-induced Sbno2 expression lasts for at least 12 h in astrocytes. Inhibition of transcription by actinomycin D revealed Sbno2 mRNA has a half-life of 51 min in these cells. In NIH-3T3 fibroblasts the transgenic SBNO2 was found to localise exclusively to the nucleus but not the nucleoli.

Conclusions: (1) Sbno2 is a primary response gene to hyper-IL-6 and is able to be regulated by hyper-IL-6 in the absence of additional protein synthesis, (2) its mRNA levels are tightly regulated, and (3) transgenic SBNO2 localises exclusively to the nucleus consistent with a role as a transcriptional regulator.