Skip to main content
Top
Published in: Journal of Neuroinflammation 1/2022

Open Access 01-12-2022 | Research

Effect of rottlerin on astrocyte phenotype polarization after trimethyltin insult in the dentate gyrus of mice

Authors: Yeonggwang Hwang, Hyoung-Chun Kim, Eun-Joo Shin

Published in: Journal of Neuroinflammation | Issue 1/2022

Login to get access

Abstract

Background

It has been demonstrated that reactive astrocytes can be polarized into pro-inflammatory A1 phenotype or anti-inflammatory A2 phenotype under neurotoxic and neurodegenerative conditions. Microglia have been suggested to play a critical role in astrocyte phenotype polarization by releasing pro- and anti-inflammatory mediators. In this study, we examined whether trimethyltin (TMT) insult can induce astrocyte polarization in the dentate gyrus of mice, and whether protein kinase Cδ (PKCδ) plays a role in TMT-induced astrocyte phenotype polarization.

Methods

Male C57BL/6 N mice received TMT (2.6 mg/kg, i.p.), and temporal changes in the mRNA expression of A1 and A2 phenotype markers were evaluated in the hippocampus. In addition, temporal and spatial changes in the protein expression of C3, S100A10, Iba-1, and p-PKCδ were examined in the dentate gyrus. Rottlerin (5 mg/kg, i.p. × 5 at 12-h intervals) was administered 3–5 days after TMT treatment, and the expression of A1 and A2 transcripts, p-PKCδ, Iba-1, C3, S100A10, and C1q was evaluated 6 days after TMT treatment.

Results

TMT treatment significantly increased the mRNA expression of A1 and A2 phenotype markers, and the increased expression of A1 markers remained longer than that of A2 markers. The immunoreactivity of the representative A1 phenotype marker, C3 and A2 phenotype marker, S100A10 peaked 6 days after TMT insult in the dentate gyrus. While C3 was expressed evenly throughout the dentate gyrus, S100A10 was highly expressed in the hilus and inner molecular layer. In addition, TMT insult induced microglial p-PKCδ expression. Treatment with rottlerin, a PKCδ inhibitor, decreased Iba-1 and C3 expression, but did not affect S100A10 expression, suggesting that PKCδ inhibition attenuates microglial activation and A1 astrocyte phenotype polarization. Consistently, rottlerin significantly reduced the expression of C1q and tumor necrosis factor-α (TNFα), which has been suggested to be released by activated microglia and induce A1 astrocyte polarization.

Conclusion

We demonstrated the temporal and spatial profiles of astrocyte polarization after TMT insult in the dentate gyrus of mice. Taken together, our results suggest that PKCδ plays a role in inducing A1 astrocyte polarization by promoting microglial activation and consequently increasing the expression of pro-inflammatory mediators after TMT insult.
Appendix
Available only for authorised users
Literature
23.
24.
go back to reference Eun SY, Kim EH, Kang KS, Kim HJ, Jo SA, Kim SJ, et al. Cell type-specific upregulation of myristoylated alanine-rich C kinase substrate and protein kinase C-alpha, -beta I, -beta II, and -delta in microglia following kainic acid-induced seizures. Exp Mol Med. 2006;38(3):310–9. https://doi.org/10.1038/emm.2006.37.CrossRefPubMed Eun SY, Kim EH, Kang KS, Kim HJ, Jo SA, Kim SJ, et al. Cell type-specific upregulation of myristoylated alanine-rich C kinase substrate and protein kinase C-alpha, -beta I, -beta II, and -delta in microglia following kainic acid-induced seizures. Exp Mol Med. 2006;38(3):310–9. https://​doi.​org/​10.​1038/​emm.​2006.​37.CrossRefPubMed
27.
go back to reference Kreyberg S, Torvik A, Bjorneboe A, Wiik-Larsen W, Jacobsen D. Trimethyltin poisoning: report of a case with postmortem examination. Clin Neuropathol. 1992;11(5):256–9.PubMed Kreyberg S, Torvik A, Bjorneboe A, Wiik-Larsen W, Jacobsen D. Trimethyltin poisoning: report of a case with postmortem examination. Clin Neuropathol. 1992;11(5):256–9.PubMed
29.
go back to reference Brown AW, Aldridge WN, Street BW, Verschoyle RD. The behavioral and neuropathologic sequelae of intoxication by trimethyltin compounds in the rat. Am J Pathol. 1979;97(1):59–82.PubMedPubMedCentral Brown AW, Aldridge WN, Street BW, Verschoyle RD. The behavioral and neuropathologic sequelae of intoxication by trimethyltin compounds in the rat. Am J Pathol. 1979;97(1):59–82.PubMedPubMedCentral
30.
go back to reference Dyer RS, Walsh TJ, Wonderlin WF, Bercegeay M. The trimethyltin syndrome in rats. Neurobehav Toxicol Teratol. 1982;4(2):127–33.PubMed Dyer RS, Walsh TJ, Wonderlin WF, Bercegeay M. The trimethyltin syndrome in rats. Neurobehav Toxicol Teratol. 1982;4(2):127–33.PubMed
32.
go back to reference Segal M. Behavioral and physiological effects of trimethyltin in the rat hippocampus. Neurotoxicology. 1988;9(3):481–9.PubMed Segal M. Behavioral and physiological effects of trimethyltin in the rat hippocampus. Neurotoxicology. 1988;9(3):481–9.PubMed
35.
go back to reference Chang LW, Wenger GR, McMillan DE, Dyer RS. Species and strain comparison of acute neurotoxic effects of trimethyltin in mice and rats. Neurobehav Toxicol Teratol. 1983;5(3):337–50.PubMed Chang LW, Wenger GR, McMillan DE, Dyer RS. Species and strain comparison of acute neurotoxic effects of trimethyltin in mice and rats. Neurobehav Toxicol Teratol. 1983;5(3):337–50.PubMed
93.
Metadata
Title
Effect of rottlerin on astrocyte phenotype polarization after trimethyltin insult in the dentate gyrus of mice
Authors
Yeonggwang Hwang
Hyoung-Chun Kim
Eun-Joo Shin
Publication date
01-12-2022
Publisher
BioMed Central
Published in
Journal of Neuroinflammation / Issue 1/2022
Electronic ISSN: 1742-2094
DOI
https://doi.org/10.1186/s12974-022-02507-w

Other articles of this Issue 1/2022

Journal of Neuroinflammation 1/2022 Go to the issue