Limits...
Neuroprotection by the histone deacetylase inhibitor trichostatin A in a model of lipopolysaccharide-sensitised neonatal hypoxic-ischaemic brain injury.

Fleiss B, Nilsson MK, Blomgren K, Mallard C - J Neuroinflammation (2012)

Bottom Line: Also only in females, TSA reduced grey matter and white matter injury at 5 days post-LPS/HI.Treatment altered animal behaviour in the open field and improved learning in the fear-conditioning test in females compared with LPS/HI-only females at 25 days post-HI.TSA did not impair oligodendrocyte maturation, which increases the possible clinical relevance of this strategy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Perinatal Center, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Box 432, Gothenburg, 405 30, Sweden. bobbi.fleiss@inserm.fr

ABSTRACT

Background: Perinatal brain injury is complex and often associated with both inflammation and hypoxia-ischaemia (HI). In adult inflammatory brain injury models, therapies to increase acetylation are efficacious in reducing inflammation and cerebral injury. Our aim in the present study was to examine the neuropathological and functional effects of the histone deacetylase inhibitor (HDACi) trichostatin A (TSA) in a model of neonatal lipopolysaccharide (LPS)-sensitised HI. We hypothesised that, by decreasing inflammation, TSA would improve injury and behavioural outcome. Furthermore, TSA's effects on oligodendrocyte development, which is acetylation-dependent, were investigated.

Methods: On postnatal day 8 (P8), male and female mice were exposed to LPS together with or without TSA. On P9 (14 hours after LPS), mice were exposed to HI (50 minutes at 10% O2). Neuropathology was assessed at 24 hours, 5 days and 27 days post-LPS/HI via immunohistochemistry and/or Western blot analysis for markers of grey matter (microtubule-associated protein 2), white matter (myelin basic protein) and cell death (activated caspase-3). Effects of TSA on LPS or LPS/HI-induced inflammation (cytokines and microglia number) were assessed by Luminex assay and immunohistochemistry. Expression of acetylation-dependent oligodendrocyte maturational corepressors was assessed with quantitative PCR 6 hours after LPS and at 24 hours and 27 days post-LPS/HI. Animal behaviour was monitored with the open-field and trace fear-conditioning paradigms at 25 days post-LPS/HI to identify functional implications of changes in neuropathology associated with TSA treatment.

Results: TSA induced increased Ac-H4 in females only after LPS exposure. Also only in females, TSA reduced grey matter and white matter injury at 5 days post-LPS/HI. Treatment altered animal behaviour in the open field and improved learning in the fear-conditioning test in females compared with LPS/HI-only females at 25 days post-HI. None of the inflammatory mechanisms assessed that are known to mediate neuroprotection by HDACi in adults correlated with improved outcome in TSA-treated neonatal females. Oligodendrocyte maturation was not different between the LPS-only and LPS + TSA-treated mice before or after exposure to HI.

Conclusions: Hyperacetylation with TSA is neuroprotective in the female neonatal mouse following LPS/HI and correlates with improved learning long-term. TSA appears to exert neuroprotection via mechanisms unique to the neonate. Deciphering the effects of age, sex and inflammatory sensitisation in the cerebral response to HDACi is key to furthering the potential of hyperacetylation as a viable neuroprotectant. TSA did not impair oligodendrocyte maturation, which increases the possible clinical relevance of this strategy.

Show MeSH

Related in: MedlinePlus

Trichostatin A (TSA) persistently increases histone acetylation at 24 hours after injury. (A) Western blots of acetylated histone-4(Ac-H4), acetylated histone-3 (Ac-H3, molecular weight 17 kDa) and reference protein H2B in female lipopolysaccharide-sensitised hypoxiaischaemia (LPS/HI) mice (red bars) and LPS + TSA/HI mice (green bars) 24 hours after injury. (B) and (C) Mean normalised acetylation data are shown for Ac-H4 (B) and Ac-H3 (C) (all n = 7). Data are means ± SEM. *P<0.05 treatment effect by one-way ANOVA, #P<0.05 by post hoc t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3420244&req=5

Figure 3: Trichostatin A (TSA) persistently increases histone acetylation at 24 hours after injury. (A) Western blots of acetylated histone-4(Ac-H4), acetylated histone-3 (Ac-H3, molecular weight 17 kDa) and reference protein H2B in female lipopolysaccharide-sensitised hypoxiaischaemia (LPS/HI) mice (red bars) and LPS + TSA/HI mice (green bars) 24 hours after injury. (B) and (C) Mean normalised acetylation data are shown for Ac-H4 (B) and Ac-H3 (C) (all n = 7). Data are means ± SEM. *P<0.05 treatment effect by one-way ANOVA, #P<0.05 by post hoc t-test.

Mentions: Using Western blot analysis, we demonstrated that TSA dose-dependently increased H4 acetylation in the brain at 14 hours after LPS exposure (Figure 2) (P < 0.001 by one-way ANOVA), as previously reported [32]. We also monitored indices of pup health, that is, pup weight gain, rectal temperature and the presence of righting reflex. TSA dose-dependently decreased weight gain and rectal temperature (P < 0.05 by one-way ANOVA) (Figures 3A and 3B). Also, pups in the 10-mg group displayed a loss of righting reflex (data not shown), but there was no significant difference in mortality up to 14 hours after treatment ( Additional file 3: Table S2).


Neuroprotection by the histone deacetylase inhibitor trichostatin A in a model of lipopolysaccharide-sensitised neonatal hypoxic-ischaemic brain injury.

Fleiss B, Nilsson MK, Blomgren K, Mallard C - J Neuroinflammation (2012)

Trichostatin A (TSA) persistently increases histone acetylation at 24 hours after injury. (A) Western blots of acetylated histone-4(Ac-H4), acetylated histone-3 (Ac-H3, molecular weight 17 kDa) and reference protein H2B in female lipopolysaccharide-sensitised hypoxiaischaemia (LPS/HI) mice (red bars) and LPS + TSA/HI mice (green bars) 24 hours after injury. (B) and (C) Mean normalised acetylation data are shown for Ac-H4 (B) and Ac-H3 (C) (all n = 7). Data are means ± SEM. *P<0.05 treatment effect by one-way ANOVA, #P<0.05 by post hoc t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3420244&req=5

Figure 3: Trichostatin A (TSA) persistently increases histone acetylation at 24 hours after injury. (A) Western blots of acetylated histone-4(Ac-H4), acetylated histone-3 (Ac-H3, molecular weight 17 kDa) and reference protein H2B in female lipopolysaccharide-sensitised hypoxiaischaemia (LPS/HI) mice (red bars) and LPS + TSA/HI mice (green bars) 24 hours after injury. (B) and (C) Mean normalised acetylation data are shown for Ac-H4 (B) and Ac-H3 (C) (all n = 7). Data are means ± SEM. *P<0.05 treatment effect by one-way ANOVA, #P<0.05 by post hoc t-test.
Mentions: Using Western blot analysis, we demonstrated that TSA dose-dependently increased H4 acetylation in the brain at 14 hours after LPS exposure (Figure 2) (P < 0.001 by one-way ANOVA), as previously reported [32]. We also monitored indices of pup health, that is, pup weight gain, rectal temperature and the presence of righting reflex. TSA dose-dependently decreased weight gain and rectal temperature (P < 0.05 by one-way ANOVA) (Figures 3A and 3B). Also, pups in the 10-mg group displayed a loss of righting reflex (data not shown), but there was no significant difference in mortality up to 14 hours after treatment ( Additional file 3: Table S2).

Bottom Line: Also only in females, TSA reduced grey matter and white matter injury at 5 days post-LPS/HI.Treatment altered animal behaviour in the open field and improved learning in the fear-conditioning test in females compared with LPS/HI-only females at 25 days post-HI.TSA did not impair oligodendrocyte maturation, which increases the possible clinical relevance of this strategy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Perinatal Center, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Box 432, Gothenburg, 405 30, Sweden. bobbi.fleiss@inserm.fr

ABSTRACT

Background: Perinatal brain injury is complex and often associated with both inflammation and hypoxia-ischaemia (HI). In adult inflammatory brain injury models, therapies to increase acetylation are efficacious in reducing inflammation and cerebral injury. Our aim in the present study was to examine the neuropathological and functional effects of the histone deacetylase inhibitor (HDACi) trichostatin A (TSA) in a model of neonatal lipopolysaccharide (LPS)-sensitised HI. We hypothesised that, by decreasing inflammation, TSA would improve injury and behavioural outcome. Furthermore, TSA's effects on oligodendrocyte development, which is acetylation-dependent, were investigated.

Methods: On postnatal day 8 (P8), male and female mice were exposed to LPS together with or without TSA. On P9 (14 hours after LPS), mice were exposed to HI (50 minutes at 10% O2). Neuropathology was assessed at 24 hours, 5 days and 27 days post-LPS/HI via immunohistochemistry and/or Western blot analysis for markers of grey matter (microtubule-associated protein 2), white matter (myelin basic protein) and cell death (activated caspase-3). Effects of TSA on LPS or LPS/HI-induced inflammation (cytokines and microglia number) were assessed by Luminex assay and immunohistochemistry. Expression of acetylation-dependent oligodendrocyte maturational corepressors was assessed with quantitative PCR 6 hours after LPS and at 24 hours and 27 days post-LPS/HI. Animal behaviour was monitored with the open-field and trace fear-conditioning paradigms at 25 days post-LPS/HI to identify functional implications of changes in neuropathology associated with TSA treatment.

Results: TSA induced increased Ac-H4 in females only after LPS exposure. Also only in females, TSA reduced grey matter and white matter injury at 5 days post-LPS/HI. Treatment altered animal behaviour in the open field and improved learning in the fear-conditioning test in females compared with LPS/HI-only females at 25 days post-HI. None of the inflammatory mechanisms assessed that are known to mediate neuroprotection by HDACi in adults correlated with improved outcome in TSA-treated neonatal females. Oligodendrocyte maturation was not different between the LPS-only and LPS + TSA-treated mice before or after exposure to HI.

Conclusions: Hyperacetylation with TSA is neuroprotective in the female neonatal mouse following LPS/HI and correlates with improved learning long-term. TSA appears to exert neuroprotection via mechanisms unique to the neonate. Deciphering the effects of age, sex and inflammatory sensitisation in the cerebral response to HDACi is key to furthering the potential of hyperacetylation as a viable neuroprotectant. TSA did not impair oligodendrocyte maturation, which increases the possible clinical relevance of this strategy.

Show MeSH
Related in: MedlinePlus