Inhibition of HDAC3 and ATXN3 by miR-25 prevents neuronal loss and ameliorates neurological recovery in cerebral stroke experimental rats

Environmental enrichment promotes functional recovery from stroke via enhancing neuroplasticity through the action of -HB

Stroke is a leading cause of adult disability worldwide, unfortunately, no drugs are clinically available to promote functional recovery after stroke. Although animal environmental enrichment is a recognized paradigm for promoting stroke repair, elusive mechanisms hinder its clinical translation. Here, we show that β-hydroxybutyrate (β-HB) level in the peri-infarct cortex is upregulated after environmental enrichment (EE) exposure. Importantly, exogenous supplementation of β-HB promotes functional recovery to a similar extent as EE exposure. Moreover, the beneficial effects of EE on stroke recovery, including functional recovery, neuroplasticity-related proteins upregulation, and structural and functional plasticity enhancement, are abolished by β-HB transporter inhibitor, AR-C155858. Intriguingly, supplementation with (R)-3-hydroxybutyl (R)-β-HB, a ketone ester (KE), substantially increases β-HB level and lessens motor functional impairments. Together, our findings indicate that β-HB is a critical substrate for EE-mediated stroke recovery and supplementation with β-HB monoester drinks may serve as a novel strategy to translate EE from bench to bedside.

Upregulation of HDAC3 mediates behavioral impairment in the bile duct ligation model of hepatic encephalopathy

Hepatic encephalopathy (HE), an outcome of chronic liver disease is characterized by behavioral impairments. The present study investigated the role of HDAC-mediated transcriptional regulation causing behavioral impairments in the bile duct ligation (BDL) model of HE. Post-BDL surgery in rats, dynamic alterations in liver function tests, liver morphology were observed. In BDL rats, histological staining in brain demonstrated reduced neuronal viability and warped neuronal architecture. Additionally, BDL animals showed impaired spatial learning, memory, and increased anxiety in the open field, Barnes maze, and Y maze tests. Further, the Golgi cox staining revealed a significantly altered spine density and spine clustering patterns of granular neuron in dentate gyrus of BDL rats. Concordantly, a significant downregulation of memory encoding genes was also observed in BDL rats that may account for aberrant behavior. Molecular analysis of modifiers, such as HDAC, showed significant changes in the expression of HDAC3 and HDAC6 in both the cortex and hippocampus of BDL rats. Upregulation of HDAC3 promoted its localization on the promoter of genes like c-Fos, NPAS4, Arc, and others, likely causing their decreased expression. Our findings suggest that increased HDAC3 activity downregulates key synaptic plasticity and memory-related genes, potentially driving neurobehavioral changes in BDL rats.

Predictors of delayed encephalopathy after acute carbon monoxide poisoning: a literature review

Delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) is one of the severe complications that can occur after acute carbon monoxide poisoning (ACOP). The pathogenesis of DEACMP is complex, featuring a delitescence onset and poor prognosis. As a result, many scholars are concentrating on identifying predictors of DEACMP and evaluating their effects, including clinical characteristics, laboratory indicators, neuroelectrophysiology, imaging examination, and genetic susceptibility. However, current identified predictors lack consensus and their clinical application is limited. Therefore, we need to explore new predictors. Exosomes, the smallest extracellular vesicles (EVs) with nano-size, participate in both the physiological and pathological processes of the brain, and the changes in their content can provide valuable information for clinical diagnosis and evaluation of neurodegenerative diseases, suggesting that they may serve as a potential biomarker. However, the practicability of exosomes as biomarkers of DEACMP remains unclear. In the present review, we first introduced the pathogenesis of DEACMP and the currently identified predictors. Then, we also discussed the possibility of exosomes as the biomarkers of DEACMP, aiming to stimulate more attention and discussion on this topic, thereby providing meaningful insights for future research.

Cell-Free Nucleic Acids for Early Diagnosis of Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Rapid identification of acute ischemic stroke (AIS) is challenging in both pre-hospital and hospital settings. We aimed to identify the most promising cell-free nucleic acids (cfNAs) as diagnostic biomarkers for IS within 72 h from symptom onset. We searched PubMed, Web of Science, EMBASE, and Cochrane Library for published articles that evaluated blood cfNAs in the early diagnosis of AIS until 10 May 2023. The diagnostic performances of individual cfNAs were pooled by random-effects meta-analysis based on the fold change of biomarkers' level between AIS and non-AIS patients. Of 2955 records, 66 articles reporting 143 different cfNAs met the inclusion criteria. The median sample size was 110, and 21.4% of the studies performed validation. Among selected high-quality studies, miR-106b-5p, miR-124, miR-155, lncRNA H19, and cfDNA showed good diagnostic performance. Data from four studies on cfDNA involving 355 AIS patients and 97 controls were pooled in the meta-analysis, which showed a significant fold change between AIS and controls (pooled ratio 1.48, 95% confidence interval 1.23-1.79, p < 0.001). This review highlights that cfDNA, miR-106b-5p, miR-124, miR-155, and lncRNA H19 are the most promising biomarkers for AIS diagnosis, and further research is needed for verification.

Treadmill exercise improves cerebral ischemia injury by regulating microglia polarization via downregulation of MMP12

BACKGROUD

Exercise training is the main strategy for stroke rehabilitation, and it has shown that shifting microglia toward M2 phenotype is beneficial for the recovery of neurological function after stroke. The mechanisms governing exercise training and inflammatory response after cerebral ischemia remain largely unexplored. Herein, the aim of this study was to investigate the role of exercise training in immune response after cerebral ischemia.

METHODS

The transient middle cerebral artery occlusion (MCAO) rat model and primary microglia under oxygen-glucose deprivation/reoxygenation (OGD/R) conditions were used to mimic the ischemic stroke in vivo and in vitro respectively. Treadmill exercise with gradually increased intensity was initiated the second day after MCAO for a maximum of 14 days. The beam balance test, forelimb placement test, cornering test, modified adhesive removal test were used to assess the behavioral recovery. The right peri-infarct cortex was taken from 3 rats per group for RNA sequencing (RNA-seq) analysis. Real-time PCR, western blot, immunofluorescence, and phagocytosis assay was performed after MCAO and/or OGD/R.

RESULTS

Treadmill exercise could significantly improve behavioral outcomes and reduce the infarct volumes. In addition, treadmill exercise switched microglia polarization toward M2 phenotype (Iba+/CD206+) in the peri-infarct cortex, and significantly increased the levels of anti-inflammatory factors (TGF-β, IL10, Arg-1, CD206) and decreased a pool of pro-inflammatory factors (IL-1β, IL-6, TNF-α, iNOS, CD68) in the peri-infarct areas. RNA-seq analysis and further studies demonstrated that exercise training could significantly reduce the expression of MMP12. Through further immunofluorescence co-labeling analysis, we found that treadmill exercise predominantly reduced the expression of MMP-12 in microglia but not in neuron after MCAO. In primary microglia after OGD/R, MMP12 inhibition switched microglia polarization toward to M2 phenotype, increased the expression of M2 markers, and enhanced its phagocytic capacities.

CONCLUSIONS

Our data demonstrate that treadmill exercise could improve the inflammatory microenvironment in the brain after ischemic stroke, which may be caused by inhibition of MMP12 expression. MMP12 suppression in primary microglia could remodel microglia immune functions. In summary, this study may provide novel insights into the immune mechanism of exercise training for stroke and suggests potential targets for therapeutic approaches.

Pterostilbene improves neurological dysfunction and neuroinflammation after ischaemic stroke via HDAC3/Nrf1-mediated microglial activation

BACKGROUND

Stroke is a type of acute brain damage that can lead to a series of serious public health challenges. Demonstrating the molecular mechanism of stroke-related neural cell degeneration could help identify a more efficient treatment for stroke patients. Further elucidation of factors that regulate microglia and nuclear factor (erythroid-derived 2)-like 1 (Nrf1) may lead to a promising strategy for treating neuroinflammation after ischaemic stroke. In this study, we investigated the possible role of pterostilbene (PTS) in Nrf1 regulation in cell and animal models of ischaemia stroke.

METHODS

We administered PTS, ITSA1 (an HDAC activator) and RGFP966 (a selective HDAC3 inhibitor) in a mouse model of middle cerebral artery occlusion-reperfusion (MCAO/R) and a model of microglial oxygen‒glucose deprivation/reperfusion (OGD/R). The brain infarct size, neuroinflammation and microglial availability were also determined. Dual-luciferase reporter, Nrf1 protein stability and co-immunoprecipitation assays were conducted to analyse histone deacetylase 3 (HDAC3)/Nrf1-regulated Nrf1 in an OGD/R-induced microglial injury model.

RESULTS

We found that PTS decreased HDAC3 expression and activity, increased Nrf1 acetylation in the cell nucleus and inhibited the interaction of Nrf1 with p65 and p65 accumulation, which reduced infarct volume and neuroinflammation (iNOS/Arg1, TNF-α and IL-1β levels) after ischaemic stroke. Furthermore, the CSF1R inhibitor PLX5622 induced elimination of microglia and attenuated the therapeutic effect of PTS following MCAO/R. In the OGD/R model, PTS relieved OGD/R-induced microglial injury and TNF-α and IL-1β release, which were dependent on Nrf1 acetylation through the upregulation of HDAC3/Nrf1 signalling in microglia. However, the K105R or/and K139R mutants of Nrf1 counteracted the impact of PTS in the OGD/R-induced microglial injury model, which indicates that PTS treatment might be a promising strategy for ischaemia stroke therapy.

CONCLUSION

The HDAC3/Nrf1 pathway regulates the stability and function of Nrf1 in microglial activation and neuroinflammation, which may depend on the acetylation of the lysine 105 and 139 residues in Nrf1. This mechanism was first identified as a potential regulatory mechanism of PTS-based neuroprotection in our research, which may provide new insight into further translational applications of natural products such as PTS.

Ketone bodies promote stroke recovery via GAT-1-dependent cortical network remodeling

Stroke is a leading cause of adult disability worldwide, and better drugs are needed to promote functional recovery after stroke. Growing evidence suggests the critical role of network excitability during the repair phase for stroke recovery. Here, we show that β-hydroxybutyrate (β-HB), an essential ketone body (KB) component, is positively correlated with improved outcomes in patients with stroke and promotes functional recovery in rodents with stroke during the repair phase. These beneficial effects of β-HB depend on HDAC2/HDAC3-GABA transporter 1 (GAT-1) signaling-mediated enhancement of excitability and phasic GABA inhibition in the peri-infarct cortex and structural and functional plasticity in the ipsilateral cortex, the contralateral cortex, and the corticospinal tract. Together with available clinical approaches to elevate KB levels, our results offer a clinically translatable means to promote stroke recovery. Furthermore, GAT-1 can serve as a pharmacological target for developing drugs to promote functional recovery after stroke.

The SIK1/CRTC2/CREB1 and TWIST1/PI3K/Akt/GSK3β signaling pathways mediated by microRNA-25-3p are altered in the schizophrenic rat brain

Schizophrenia is a group of severe mental disorders. MiR-25-3p was shown to be involved in various neuropsychiatric diseases and can regulate SIK1 and TWIST1. The CRTC2/CREB1 and PI3K/Akt/GSK3β signaling pathways are downstream pathways of SIK1 and TWIST1, respectively. This study investigated whether miR-25-3p-mediated SIK1/CRTC2/CREB1 and TWIST1/PI3K/Akt/GSK3β signaling pathways are present in an animal model relevant to schizophrenia. A schizophrenic rat model was established by using sub-chronic MK-801 administration. An RNA-seq test was performed to examine the differentially expressed genes (DEGs) in the rat prefrontal cortex (PFC). The mRNA levels of miR-25-3p, SIK1, and TWIST in the PFC and caudate putamen (CPu) were assessed by qRT-PCR. Phosphorylation of the SIK1/CRTC2/CREB1 and TWIST1/PI3K/Akt/GSK3β pathways in the two brain regions was examined by Western blots. The RNA-seq data revealed down-regulated miR-25-3p expression and up-regulated SIK1 and TWIST1 mRNA expression induced by MK-801. Additionally, SIK1 and TWIST1 were shown to be possible downstream responders of miR-25-3p in previous studies. qRT-PCR confirmed the changes of miR-25-3p, SIK1, and TWIST1 induced by MK-801 in both brain regions, which, however, was reversed by risperidone. Furthermore, the phosphorylation of the SIK1/CRTC2/CREB1 pathway was repressed by MK-801, whereas the phosphorylation of the TWIST1/PI3K/Akt/GSK3β pathway was increased by MK-801 in either of the two brain regions. Moreover, the altered phosphorylation of these two signaling pathways induced by MK-801 can be restored by risperidone. In conclusion, this study suggests that altered SIK1/CRTC2/CREB1 and TWIST1/PI3K/Akt/GSK3β signaling pathways mediated by miR-25-3p is very likely to be associated with schizophrenia, revealing potential targets for the treatment and clinical diagnosis of schizophrenia.

H2S-mediated inhibition of RhoA/ROCK pathway and noncoding RNAs in ischemic stroke

Ischemic stroke is one of major causes of disability. In the pathological process of ischemic stroke, the up-regulation of Ras homolog gene family, member A (RhoA) and its downstream effector, Ras homolog gene family (Rho)-associated coiled coil-containing kinase (ROCK), contribute to the neuroinflammation, blood-brain barrier (BBB) dysfunction, neuronal apoptosis, axon growth inhibition and astrogliosis. Accumulating evidences have revealed that hydrogen sulphide (H₂S) could reduce brain injury in animal model of ischemic stroke via inhibiting the RhoA/ROCK pathway. Recently, noncoding RNAs (ncRNAs) such as circular RNAs (circRNAs), long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have attracted much attention because of their essential role in adjusting gene expression both in physiological and pathological conditions. Numerous studies have uncovered the role of RhoA/ROCK pathway and ncRNAs in ischemic stroke. In this review, we focused on the role of H₂S, RhoA/ROCK pathway and ncRNAs in ischemic stroke and aimed to reveal new strategies for preventing and treating this devastating disease.

Histone Deacetylase 3 Inhibition Decreases Cerebral Edema and Protects the Blood–Brain Barrier After Stroke

We have previously shown that selective inhibition of histone deacetylase 3 (HDAC3) decreases infarct volume and improves long-term functional outcomes after stroke. In this study, we examined the effects of HDAC3 inhibition on cerebral edema and blood–brain barrier (BBB) leakage and explored its underlying mechanisms. Adult male Wistar rats were subjected to 2-h middle cerebral artery occlusion (MCAO) and randomly treated i.p. with either vehicle or a selective HDAC3 inhibitor (RGFP966) at 2 and 24 h after stroke. Modified neurological severity scores (mNSS) were calculated at 2 h, 1 day, and 3 days. H&E, Evans blue dye (EBD) assay, and fluorescein isothiocyanate (FITC)-dextran were employed to assess cerebral edema and BBB leakage. Western blot for matrix metalloproteinase-9 (MMP9), MMP-9 zymography, and immunostaining for HDAC3, GFAP, Iba-1, albumin, aquaporin-4, claudin-5, ZO-1, and NF-kB were performed. Early RGFP966 administration decreased cerebral edema (p = 0.002) and BBB leakage, as measured by EBD assay, FITC-dextran, and albumin extravasation (p < 0.01). RGFP966 significantly increased tight junction proteins (claudin-5 and ZO-1) in the peri-infarct area. RGFP966 also significantly decreased HDAC3 in GFAP + astrocytes, which correlated with better mNSS (r = 0.67, p = 0.03) and decreased cerebral edema (r = 0.64, p = 0.04). RGFP966 decreased aquaporin-4 in GFAP + astrocytes (p = 0.002), as well as, the inflammatory markers Iba-1, NF-kB, and MMP9 in the ischemic brain (p < 0.05). Early HDAC3 inhibition decreases cerebral edema and BBB leakage. BBB protection by RGFP966 is mediated in part by the upregulation of tight junction proteins, downregulation of aquaporin-4 and HDAC3 in astrocytes, and decreased neuroinflammation.

Efficacy of Fuyuan Xingshen Decoction Combined with Butylphthalide Sodium Chloride Injection in the Treatment of Acute Cerebral Infarction and Its Effect on Hemodynamics

Objective. This study aims to determine the curative effect of Fuyuan Xingshen Decoction combined with butylphthalide sodium chloride injection in acute cerebral infarction (ACI) treatment and its effect on hemodynamics. Methods. In our hospital, a total of 84 ACI patients from May 2020 to February 2022 were randomly divided into two groups: observation and control (n = 42 each). Fuyuan Xingshen Decoction in combination with butylphthalide sodium chloride injection was provided to the observation group, while the control group received butylphthalide sodium chloride injection alone. Both groups’ clinical efficacy was observed. Before and after treatment, the neurological function of the two groups was evaluated using the National Institutes of Health Stroke Scale (NIHSS), while the daily living ability of both groups was determined using the Barthel index rating scale. Both groups were investigated for their cognitive function, before and after treatment, by using the Mini-Cog scale and Montreal Cognitive Assessment (MoCA) scale. The pulsatility index (PI), peak velocity (Vp), and mean velocity (Vm) of intracranial arteries were measured by transcranial Doppler ultrasonography before and after treatment. The levels of ubiquitin carboxy-terminal hydrolase-1 (UCH-L1), Fibulin-5, and visinin-like protein-1 (VILIP-1) in serum and the expression levels of miR-34c, miR-25, and miR-182 in peripheral blood of the two groups were compared. Both groups were observed for the incidence of adverse reactions. Results. Compared with the control (71.43%), the observation group exhibited a significantly higher effective rate of around 90.48%. In the observation group, the improvement in NIHSS, Barthel index, Mini-cog, and MoCA scores; hemodynamic indexes including Vp, PI, and Vm; serum UCH-L1, Fibulin-5, and VILIP-1 levels; and the miR-34c, miR-25, and miR-182 expression levels in peripheral blood was better than the control group, with significant difference (all $P<0.05$ ). The incidence of adverse reactions between the groups demonstrated no significant differences ( $P>0.05$ ). Conclusions. Fuyuan Xingshen Decoction combined with butylphthalide sodium chloride injection can effectively improve patients’ daily living ability, neurological function, cognitive function, and cerebral hemodynamics in the treatment of ACI, with good effect and safety.