Basic fibroblast growth factor-2 and interleukin-1 beta regulate S100 beta expression in cultured astrocytes

Prior research has shown that basic fibroblast growth factor and interleukin-1 beta regulate other trophic factors and stimulate reactive gliosis in vivo. S100 beta is a glial-specific putative neurotrophic factor and is considered a marker of reactive astrocytes. However, the mechanisms by which these factors influence S100 beta expression remain unclear. No prior work had resolved whether changes in S100 beta mRNA levels are due to transcriptional regulation or post-transcriptional processes. Additionally, it was unknown whether these changes in gene expression lead to corresponding changes in protein levels. This uncertainty drove the need to investigate the effects of basic fibroblast growth factor-2 and interleukin-1 beta on S100 beta gene expression. The study aimed to clarify whether these factors influence S100 beta at the transcriptional level. Understanding this could help explain how astrocytes respond to these signaling molecules. The research sought to bridge the gap between gene expression and protein output in cultured astrocytes.

The study aimed to test whether basic fibroblast growth factor-2 and interleukin-1 beta influence S100 beta gene expression in cultured astrocytes. The researchers wanted to determine if these factors regulate S100 beta at the transcriptional level. They also sought to assess whether changes in mRNA levels correspond to changes in protein levels. The hypothesis was that these factors alter S100 beta gene expression through transcriptional mechanisms. The study focused on rat astrocytes to model in vivo conditions. The researchers used an RNase protection assay to measure mRNA levels. They also measured nuclear primary transcripts to evaluate transcriptional changes. The goal was to clarify the relationship between gene expression and protein output in this context.

The researchers used cultured rat astrocytes to study the effects of basic fibroblast growth factor-2 and interleukin-1 beta. They applied short- and long-term treatments to assess temporal changes in S100 beta expression. An RNase protection assay was used to quantify S100 beta messenger RNA levels. Nuclear primary transcripts were measured to evaluate transcriptional activity. Enzyme-linked immunosorbent assay was used to assess intracellular S100 beta protein levels. The study compared the effects of both factors on mRNA and protein expression. Temporal changes in mRNA were analyzed in relation to transcriptional changes. The researchers evaluated whether transcriptional changes preceded mRNA alterations.

Short-term treatment with basic fibroblast growth factor-2 caused a transient decrease in S100 beta mRNA. Longer-term treatment led to an increase in S100 beta mRNA levels. In contrast, interleukin-1 beta suppressed S100 beta mRNA in both short- and long-term treatments. Changes in nuclear primary transcript levels preceded changes in mRNA for basic fibroblast growth factor-2. This suggests that transcriptional regulation explains mRNA changes in this case. Enzyme-linked immunosorbent assay showed that protein levels did not always reflect mRNA changes. Basic fibroblast growth factor-2 and interleukin-1 beta both influenced S100 beta gene expression. The regulation appeared to occur at the transcriptional level for basic fibroblast growth factor-2.

The study shows that basic fibroblast growth factor-2 and interleukin-1 beta influence S100 beta gene expression in astrocytes. For basic fibroblast growth factor-2, changes in transcription precede changes in mRNA. This suggests that transcriptional regulation explains the observed mRNA changes. However, protein levels do not always mirror mRNA changes. The researchers propose that basic fibroblast growth factor-2 may amplify its trophic effects by regulating another trophic factor. The study supports the idea that S100 beta expression is regulated at the transcriptional level. The findings suggest that transcriptional and post-transcriptional mechanisms may act independently. The results highlight the complexity of gene expression in astrocytes under these conditions.