Details

Autor(en) / Beteiligte

• Wang, Guohua
• Shi, Yejie
• Jiang, Xiaoyan
• Leak, Rehana K.
• Hu, Xiaoming
• Wu, Yun
• Pu, Hongjian
• Li, Wei-Wei
• Tang, Bo
• Wang, Yun
• Gao, Yanqin
• Zheng, Ping
• Bennett, Michael V. L.
• Chen, Jun

Titel

HDAC inhibition prevents white matter injury by modulating microglia/macrophage polarization through the GSK3β/PTEN/Akt axis

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2015-03, Vol.112 (9), p.2853-2858

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2015

Quelle

Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals

Beschreibungen/Notizen

• Severe traumatic brain injury (TBI) elicits destruction of both gray and white matter, which is exacerbated by secondary proinflammatory responses. Although white matter injury (WMI) is strongly correlated with poor neurological status, the maintenance of white matter integrity is poorly understood, and no current therapies protect both gray and white matter. One candidate approach that may fulfill this role is inhibition of class I/II histone deacetylases (HDACs). Here we demonstrate that the HDAC inhibitor Scriptaid protects white matter up to 35 d after TBI, as shown by reductions in abnormally dephosphorylated neurofilament protein, increases in myelin basic protein, anatomic preservation of myelinated axons, and improved nerve conduction. Furthermore, Scriptaid shifted microglia/macrophage polarization toward the protective M2 phenotype and mitigated inflammation. In primary cocultures of microglia and oligodendrocytes, Scriptaid increased expression of microglial glycogen synthase kinase 3 beta (GSK3β), which phosphorylated and inactivated phosphatase and tensin homologue (PTEN), thereby enhancing phosphatidylinositide 3-kinases (PI3K)/Akt signaling and polarizing microglia toward M2. The increase in GSK3β in microglia and their phenotypic switch to M2 was associated with increased preservation of neighboring oligodendrocytes. These findings are consistent with recent findings that microglial phenotypic switching modulates white matter repair and axonal remyelination and highlight a previously unexplored role for HDAC activity in this process. Furthermore, the functions of GSK3β may be more subtle than previously thought, in that GSK3β can modulate microglial functions via the PTEN/PI3K/Akt signaling pathway and preserve white matter homeostasis. Thus, inhibition of HDACs in microglia is a potential future therapy in TBI and other neurological conditions with white matter destruction. Significance Moderate or severe traumatic brain injury (TBI) damages white matter, thereby contributing to long-term neurological deficits. Currently, there are no satisfactory therapies to mitigate this white matter injury (WMI). Here we show that inhibition of histone deacetylases (HDACs) exerts robust structural and functional protection of white matter in a murine model of TBI/WMI by polarizing microglia/macrophages toward the beneficial M2 phenotype. HDAC inhibition shifted microglia/macrophage phenotype by up-regulating glycogen synthase kinase 3 beta (GSK3β), which inactivated phosphatase and tensin homologue (PTEN) through phosphorylation, thereby promoting PI3K/Akt signaling. The GSK3β-dependent M2 phenotype exerted potent anti-inflammatory effects that protected myelin-forming oligodendrocytes and diminished WMI. These results reveal a previously unexplored role for GSK3β/PTEN/PI3K signaling in the regulation of microglia/macrophages and demonstrate the promise of HDAC inhibition in the treatment of TBI/WMI.