Ipsilateral BDNF mRNA expression in the motor cortex positively correlates with motor function of the affected forelimb after intracerebral hemorrhage

Expression profile of circular RNAs in blood samples of Northern Chinese males with intracerebral hemorrhage shows downregulation of hsa-circ-0090829

Circular RNAs (circRNAs) are involved in several neurological disorders; however, the mechanisms underlying their involvement remain to be clarified. We attempted to explore the expression profiles of circRNAs and their potential functions and mechanisms in the pathogenesis of intracerebral hemorrhage (ICH) in Northern Chinese males. The microarray results showed that 50 circRNAs were significantly upregulated, while 194 circRNAs were significantly downregulated in ICH patients compared with healthy controls (p < 0.05). After bioinformatics analysis, a circRNA-microRNA-messenger RNA network and a protein-protein interaction network were constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the neurotrophin signaling pathway, long-term potentiation, and the mitogen-activated protein kinase pathway are potentially implicated in ICH pathophysiology. The quantitative real-time polymerase chain reaction results revealed that hsa-circ-0090829 was significantly downregulated in ICH. The receiver operating characteristic curve analysis showed that the area under the curve of hsa-circ-0090829 between ICH and healthy controls was 0.807. Furthermore, the dual-luciferase assay showed that hsa-circ-0090829 sponged miR-526b-5p. This study reports the altered expression of circRNAs and identifies the potential functions of these circRNAs in ICH. Our results may facilitate further mechanistic research on circRNAs in ICH and provide probable novel diagnostic biomarkers and therapeutic targets for ICH.

Potential effect of physical exercise on the downregulation of BDNF mRNA expression in rat hippocampus following intracerebral hemorrhage

OBJECTIVES

Physical exercise is known to induce expression of the neuroprotective brain derived neurotrophic factor (BDNF) in the hippocampus. This study examined the effects of physical exercise on hippocampal BDNF expression and the potential benefits for preventing remote secondary hippocampal damage and neurological impairment following intracerebral hemorrhage (ICH).

MATERIALS AND METHODS

Wistar rats were randomly assigned to sham-operated, ICH, and ICH followed by exercise (ICH/Ex) groups. The two ICH groups were injected with type IV collagenase into the left basal ganglia, while sham animals were injected with equal-volume saline. The ICH/Ex group rats ran on a treadmill at 11 m/min for 30 min/day from day 3 to 16 post-ICH. All animals were examined for neurological function on day 2 pretreatment and from day 3 to 15 posttreatment, for spontaneous motor activity in the open field on day 15, and for cognitive ability using the object location test on day 16. Animals were then euthanized and bilateral hippocampi collected for gene expression analyses.

RESULTS

Experimental ICH induced neurological deficits that were not reversed by exercise. In contrast, ICH did not alter spontaneous activity or object location ability. Expression of BDNF mRNA of the ICH group was significantly downregulated in the ipsilateral hippocampus compared to the SHAM group, but this downregulation was not shown in the ICH/Ex group. The ICH/Ex group showed the downregulation of caspase-3 mRNA expression in the contralateral hippocampus compared to the SHAM group, while neither ICH nor exercise influenced toll-like receptor 4 mRNA expression.

CONCLUSIONS

ICH induced the secondary BDNF downregulation in the hippocampus remote from the lesion, whereas physical exercise might partially mitigate the downregulation.

Pharmacological inhibition of histone deacetylases ameliorates cognitive impairment after intracerebral hemorrhage with epigenetic alteration in the hippocampus

OBJECTIVES

Post-stroke cognitive impairment (PSCI) interferes with neurorehabilitation in patients with stroke. Epigenetic regulation of the hippocampus has been targeted to ameliorate cognitive function. In particular, the acetylation level of histones is modulated by exercise, a potent therapy for patients with stroke.

MATERIALS AND METHODS

We examined the effects of exercise and pharmacological inhibition of histone deacetylase (HDAC) using sodium butyrate (NaB) on cognitive function and epigenetic factors in the hippocampus after intracerebral hemorrhage (ICH) to seek beneficial neuronal conditioning against PSCI. Forty rats were randomly assigned to five groups: sham, control, NaB, exercise, and NaB plus exercise groups (n=8 in each group). Except for those in the sham group, all rats underwent stereotaxic ICH surgery with a microinjection of collagenase solution. Intraperitoneal administration of NaB (300 mg/kg) and treadmill exercise (11 m/min for 30 min) were conducted for approximately 4 weeks starting 3 days post-surgery.

RESULTS

ICH reduced cognitive function, as detected by the object location test, accompanied by enhanced activity of HDACs. Although exercise did not modulate HDAC activity or cognitive function, repetitive NaB administration increased HDAC activity and ameliorated cognitive impairment induced by ICH.

CONCLUSIONS

This study suggests that pharmacological treatment with an HDAC inhibitor could potentially present an enriched epigenetic platform in the hippocampus and ameliorate PSCI for neurorehabilitation following ICH.

Epigenetic modifications in the motor cortex caused by exercise or pharmacological inhibition of histone deacetylases (HDACs) after intracerebral hemorrhage (ICH)

Epigenetic regulation is expected to provide an enriched platform for neurorehabilitation of post-stroke patients. Acetylation of specific lysine residues in histones is a potent epigenetic target essential for transcriptional regulation. Exercise modulates histone acetylation and gene expression in neuroplasticity in the brain. This study sought to examine the effect of epigenetic treatment using a histone deacetylase (HDAC) inhibitor, sodium butyrate (NaB), and exercise on epigenetic markers in the bilateral motor cortex after intracerebral hemorrhage (ICH) to identify a more enriched neuronal condition for neurorehabilitation. Forty-one male Wistar rats were randomly divided into five groups: sham (n = 8), control (n = 9), NaB, exercise (n = 8), and NaB and exercise (n = 8). Intraperitoneal administration of an HDAC inhibitor (300 mg/kg NaB) and treadmill exercise (11 m/min for 30 min) was conducted five days a week for approximately-four weeks. ICH specifically decreased the acetylation level of histone H4 in the ipsilateral cortex, and HDAC inhibition with NaB increased the acetylation level of histone H4 over the sham level, accompanied by an improvement in motor function as assessed by the cylinder test. Exercise increased the acetylation levels of histones (H3 and H4) in the bilateral cortex. Synergistic effects of exercise and NaB were not observed during histone acetylation. Pharmacological treatment with a HDAC inhibitor and exercise can provide an enriched epigenetic platform for neurorehabilitation in an individual manner.

Temporal dynamics of brain BDNF expression following a single bout of exercise: A bioluminescence imaging study

Physical exercise increases brain-derived neurotrophic factor (BDNF) expression in the brain. However, the absence of non-invasive and repetitive monitoring of BDNF expression in the brains of living animals has limited the understanding of how BDNF expression changes after exercise. This study aimed to elucidate the temporal dynamics of BDNF expression in the brain after a single bout of exercise, using in vivo bioluminescence imaging. This study included Bdnf-Luc mice with a firefly Luciferase gene inserted at the translation start site of the mouse Bdnf gene. BDNF expression was evaluated based on the luminescence signal of the luciferase substrate administered to mice. Bioluminescence imaging was performed at 0, 1, 3, 6, 12, and 24 h after treadmill exercise (15 m/min for 1 h). Compared to the sedentary condition of each mouse, the luminescence signal increased by approximately 60 % between 1 and 3 h after exercise. The luminescence signal remained slightly increased by approximately 20 % even 6-24 h after exercise. This study is the first to demonstrate exercise-enhanced BDNF expression in the brains of living animals. These results provide evidence that a single bout of exercise transiently increases BDNF expression in the brain within a limited time window.

Swimming Training Mitigates Neurological Impairment of Intracerebral Haemorrhage in Mice via the Serine-Threonine Kinase/Glycogen Synthase Kinase 3β Signalling Pathway

Swimming training (ST) can mitigate functional disorders in neurological diseases, but the effect and mechanism of ST in improving the neurological function of intracerebral haemorrhage (ICH) have not been reported. Our study aimed to explore the protective effect of early ST on ICH mice and its relationship with the serine-threonine kinase (Akt)/glycogen synthase kinase 3β (GSK3β) pathway. Our findings showed that the ICH model mice had poor behavioural manifestations in the Y maze test and open field test compared to the ST group and sham group. The modified neurological severity score was increased in the ICH mice, and 7 days of ST intervention significantly attenuated the neurological deficits. The ratios of myo-inositol/creatine, lactate/creatine and glutamate/creatine were decreased, and the ratios of N-acetylaspartate/creatine and choline/creatine were increased in the ICH mice with ST intervention. ST intervention decreased the expression of Iba1 and GFAP. Seven days of ST significantly increased the expression of p-Akt/Akt compared to that in the ICH mice. Furthermore, the Akt kinase inhibitor GSK690693 exacerbated neurological impairment, increased the expression of Iba1, GFAP and Bax/Bcl-2, and reversed the anti-apoptotic effects and anti-glia activation of ST, which was associated with the inhibition of p-Akt/Akt and p-GSK3β/GSK3β expression. These results indicated that the protective role of ST in ICH was mediated via the Akt/GSK3β pathway. In conclusion, ST displayed neuroprotection by inhibiting apoptosis and glial activation in ICH mice by activating the Akt/GSK3β signalling pathway.

Combined treatment with exercise and α5GABAAR inhibitor promotes motor function recovery after intracerebral hemorrhage

The present study aimed to examine the synergistic effects of exercise and pharmacological inhibition of the α5 subunit-containing gamma-aminobutyric acid (GABA)_A receptors (α5GABA_AR) on motor function recovery after intracerebral hemorrhage (ICH). Wistar rats were divided into five groups (n = 8 per group): SHAM, ICH, ICH + exercise (ICH + EX), ICH + L-655,708 (ICH + L6), and ICH + L-655,708 and exercise (ICH + L6EX) groups. ICH was induced by microinjection of a collagenase solution. The ICH + EX and ICH + L6EX groups exercised on a treadmill (12 m/min for 30 min/day). L-655,708 (0.5 mg/kg), a negative allosteric modulator of α5GABA_AR, was administered intraperitoneally to the ICH + L6 and ICH + L6EX groups. Each intervention was initiated 1 week after the ICH surgery and was performed for 3 weeks, followed by tissue collection, including the motor cortex and spinal cord. At 4 weeks after ICH, significant motor recovery was found in the ICH + L6EX group compared to the ICH group. L-655,708 administration increased brain-derived neurotrophic factor (BDNF) expression in the cortex. Regarding neuroplastic changes in the spinal cord, rats in the ICH + L6EX group showed a significant increase in several neuroplastic markers: 1) BDNF, 2) growth-associated protein 43 as an axonal sprouting marker, 3) synaptophysin as a synaptic marker, and 4) Nogo-A as an axonal growth inhibitor. This study is the first to demonstrate that combined treatment with exercise and α5GABA_AR inhibitor effectively promoted motor function recovery after ICH. Regarding the underlying mechanism of post-ICH recovery with the combined treatment, the present study highlights the importance of both growth and inhibitory modification of axonal sprouting in the spinal cord.