Upregulation of Cdh1 signaling in the hippocampus attenuates brain damage after transient global cerebral ischemia in rats

Effect of Berberine against Cognitive Deficits in Rat Model of Thioacetamide-Induced Liver Cirrhosis and Hepatic Encephalopathy (Behavioral, Biochemical, Molecular and Histological Evaluations)

BACKGROUND

Liver cirrhosis (LC) is one of the chronic liver diseases with high disability and mortality accompanying hepatic encephalopathy (HE) followed by cognitive dysfunctions. In this work, the effect of berberine (Ber) on spatial cognition was studied in a rat model of LC induced by thioacetamide (TAA).

MATERIALS AND METHODS

Male Wistar rats (200-250 g) were divided into six groups: (1) control; (2) TAA, 200 mg/kg/day, i.p.; (3-5) TAA + Ber; received Ber (10, 30, and 60 mg/kg, i.p., daily after last TAA injection); (6) Dizocilpine (MK-801) + TAA, received MK-801 (2 mg/kg/day, i.p.) 30 m before TAA injection. The spatial memory, BBB permeability, brain edema, liver enzymes, urea, serum and brain total bilirubin, oxidative stress and cytokine markers in the hippocampus were measured. Furthermore, a histological examination of the hippocampus was carried out.

RESULTS

The BBB permeability, brain edema, liver enzymes, urea, total bilirubin levels in serum and hippocampal MDA and TNF-α increased significantly after TAA injection (p < 0.001); the spatial memory was impaired (p < 0.001), and hippocampal IL-10 decreased (p < 0.001). Ber reversed all the above parameters significantly (p < 0.05, p < 0.01 and p < 0.001). MK-801 prevented the development of LC via TAA (p < 0.001).

CONCLUSION

Results showed that Ber improves spatial learning and memory in TAA-induced LC by improving the BBB function, oxidative stress and neuroinflammation. Ber might be a promising therapeutic agent for cognitive improvement in LC.

Therapeutic effects of growth hormone in a rat model of total sleep deprivation: Evaluating behavioral, hormonal, biochemical and electrophysiological parameters

OBJECTIVE

Total sleep deprivation (TSD) causes several harmful changes in the brain, including memory impairment, increased stress and depression levels, as well as reduced antioxidant activity. Growth hormone (GH) has been shown to boost antioxidant levels while improving memory and depression. The present study was conducted to explain the possible effects of exogenous GH against behavioral and biochemical disorders caused by TSD and the possible mechanisms involved.

MAIN METHODS

To induce TSD, rats were housed in homemade special cages equipped with stainless steel wire conductors to induce general and inconsistent TSD. They received a mild repetitive electric shock to their paws every 10 min for 21 days. GH (1 ml/kg, sc) was administered to rats during induction of TSD for 21 days. Memory retrieval, anxiety, depression-like behaviors, pain behaviors, antioxidant activity, hippocampal level of BDNF, and simultaneously brain electrical activity were measured at scheduled times after TSD.

KEY FINDINGS

The results showed that GH treatment improved memory (p < 0.001) in the PAT test of rats exposed to TSD. These beneficial effects were associated with lowering the level of anxiety and depression-like behavior (p < 0.001), rising the pain threshold (p < 0.01), increasing the activity of antioxidants (p < 0.01), hippocampal BDNF (p < 0.001), and regular brain electrical activity.

SIGNIFICANCE

Our findings show that GH plays a key role in modulating memory, anxiety and depression behaviors, as well as reducing oxidative stress and improve hippocampal single-unit activity in the brain during TSD.

HN1 Is Enriched in the S-Phase, Phosphorylated in Mitosis, and Contributes to Cyclin B1 Degradation in Prostate Cancer Cells

HN1 has previously been shown as overexpressed in various cancers. In Prostate cancer, it regulates AR signaling and centrosome-related functions. Previously, in two different studies, HN1 expression has been observed as inversely correlated with Cyclin B1. However, HN1 interacting partners and the role of HN1 interactions in cell cycle pathways have not been completely elucidated. Therefore, we used Prostate cancer cell lines again and utilized both transient and stable inducible overexpression systems to delineate the role of HN1 in the cell cycle. HN1 characterization was performed using treatments of kinase inhibitors, western blotting, flow cytometry, immunofluorescence, cellular fractionation, and immunoprecipitation approaches. Our findings suggest that HN1 overexpression before mitosis (post-G2), using both transient and stable expression systems, leads to S-phase accumulation and causes early mitotic exit after post-G2 overexpression. Mechanistically, HN1 interacted with Cyclin B1 and increased its degradation via ubiquitination through stabilized Cdh1, which is a co-factor of the APC/C complex. Stably HN1-expressing cells exhibited a reduced Cdt1 loading onto chromatin, demonstrating an exit from a G1 to S phenotype. We found HN1 and Cdh1 interaction as a new regulator of the Cyclin B1/CDK1 axis in mitotic regulation which can be explored further to dissect the roles of HN1 in the cell cycle.

Ferroptosis related genes participate in the pathogenesis of spinal cord injury via HIF-1 signaling pathway

BACKGROUND

Spinal cord injury (SCI) is a crushing disease without a effective and specific therapeutic strategy. Therefore, it is crucial to uncover underlying mechanism in order to identify potential treatments for SCI. Current studies show ferroptosis might pay important role in SCI.

METHODS

In this study, we aimed to identify the key ferroptosis-related genes providing therapeutic targets for SCI. GSE45006, GSE19890 and GSE156999 from Gene Expression Omnibus (GEO) database were analyzed.

RESULTS

A total of 61 ferroptosis-related DEGs were identified, followed by bioinformatics enrichment analyses and PPI network construction. Ten key ferroptosis-related genes were identified by Cytoscape (Cytohubba), most of which were enriched in the HIF-1 signaling pathway. Then we constructed a clip SCI rat model and qPCR was performed to assess the expressions of five genes enriched in HIF-1 signaling pathway (Stat3, Tlr4, Hmox1, Hif1a and Cybb). Finally, a ceRNA network, Stat3, Tlr4, Hmox1/miR127, miR383, miR485/rno-Mut_0003, rno-Pwwp2a_0002 was constructed and expression of mentioned molecules were validated by chip data.

CONCLUSIONS

Five hub genes from HIF-1 signaling pathway were identified and might play a central role in SCI, which indicated that ferroptosis was correlated with HIF-1 signaling pathway. These results can provide a new insight into molecular mechanisms and identify potential therapeutic targets for SCI.

Long-term exercise training down-regulates m6A RNA demethylase FTO expression in the hippocampus and hypothalamus: an effective intervention for epigenetic modification

Background

Exercise boosts the health of some brain parts, such as the hippocampus and hypothalamus. Several studies show that long-term exercise improves spatial learning and memory, enhances hypothalamic leptin sensitivity, and regulates energy balance. However, the effect of exercise on the hippocampus and hypothalamus is not fully understood. The study aimed to find epigenetic modifications or changes in gene expression of the hippocampus and hypothalamus due to exercise.

Methods

Male C57BL/6 mice were randomly divided into sedentary and exercise groups. All mice in the exercise group were subjected to treadmill exercise 5 days per week for 1 h each day. After the 12-week exercise intervention, the hippocampus and hypothalamus tissue were used for RNA-sequencing or molecular biology experiments.

Results

In both groups, numerous differentially expressed genes of the hippocampus (up-regulated: 53, down-regulated: 49) and hypothalamus (up-regulated: 24, down-regulated: 40) were observed. In the exercise group, increased level of N6-methyladenosine (m⁶A) was observed in the hippocampus and hypothalamus (p < 0.05). Furthermore, the fat mass and obesity-associated gene (FTO) of the hippocampus and hypothalamus were down-regulated in the exercise group (p < 0.001). In addition, the Fto co-expression genes of the mouse brain were studied and analyzed using database to determine the potential roles of exercise-downregulated FTO in the brain.

Conclusion

The findings demonstrate that long-term exercise might elevates the levels of m⁶A-tagged transcripts in the hippocampus and hypothalamus via down-regulation of FTO. Hence, exercise might be an effective intervention for epigenetic modification.

Neuroprotective Effects of Rhodiola Sacra on Transient Global Cerebral Ischemia Through Activating AMPK/Nrf2 Pathway in Rats

Aims: Rhodiola sacra is a widely used pharmaceutical component with multiple functions, including anti-oxidation and anti-inflammation. However, the exact mechanisms involved in neuroprotection against transient global cerebral ischemia (tGCI) remain to be elucidated. Herein, we aim at closing the gap in understanding on whether rhodiola sacra reduces neuronal death in hippocampal CA1 and at demonstrating how rhodiola sacra offers neuroprotection after tGCI. Results: The results show that rhodiola sacra (2.4 g/kg/d by feeding) pretreatment or/and postreatment significantly alleviated neuronal injury, inhibited glial activation, and improved cognitive function in male rats subjected to tGCI. The neuroprotection of prophylaxis with rhodiola sacra is equivalent to that of therapeutics. The binding mode of adenosine monophosphate-activated protein kinase (AMPK) α2-subunit with rhodiola sacra was predicted by molecular docking. Further, rhodiola sacra upregulates phosphorylated AMPK and promotes nuclear translocation of nuclear factor erythroid 2 related factor 2 (Nrf2). In addition, rhodiola sacra increases heme oxygenase-1 (HO-1) expression and activity and reduces malondialdehyde (MDA) content in CA1 after tGCI. However, the neuroprotection of rhodiola sacra is abolished by Nrf2 knockdown with small interfering RNA (siRNA) after tGCI. Similarly, the inhibition of AMPK with Compound C or siRNA against AMPK α2 aggravates neuronal death after tGCI through decreasing nuclear Nrf2 and the expression and activity of HO-1, and by increasing the release of MDA. Innovation and Conclusion: For the first time, this study demonstrates that as a prophylactic or therapeutic agent rhodiola sacra prevents oxidant stress, protects neurons, and improves cognitive function through activating the AMPK/Nrf2 pathway in tGCI rats. Antioxid. Redox Signal. 36, 567-591.

Inhibition of miR-448-3p Attenuates Cerebral Ischemic Injury by Upregulating Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2)

BACKGROUND

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator responsible for oxidative stress in brain injury. This study aimed to investigate the potential mechanism of miR-448-3p and Nrf2 in cerebral ischemia/reperfusion (I/R) injury.

METHODS

In vitro and in vivo cerebral I/R injury models were constructed, and Nrf2 expression levels were detected by qRT-PCR and Western blot. The potential miRNAs for Nrf2 were predicted by bioinformatic analysis. The binding interaction between miR-448-3p and Nrf2 was determined by luciferase reporter assay. The effects of miR-448-3p on neurological deficit, infarct volume, and brain water content in mice were tested. The effects of miR-448-3p on oxidative stress indicators (SOD activity, MDA content, and ROS production) were detected by commercial assay kits. The levels of HO-1 and cleaved caspase-3 were evaluated by Western blot. Cell viability was evaluated by MTT assay, and cell apoptosis was evaluated by TUNEL staining and flow cytometry.

RESULTS

Nrf2 was significantly downregulated and miR-448-3p was upregulated in cerebral I/R injury both in vivo and in vitro. MiR-448-3p downregulation efficiently attenuated brain injury and reduced oxidative stress and apoptosis. MiR-448-3p was identified to act as ceRNA of Nrf2 and negatively regulated Nrf2 expression, which was consistent with the animal studies. In addition, Nrf2 silencing obviously attenuated the neuroprotective effects of miR-448-3p inhibitor in vitro.

CONCLUSION

MiR-448-3p participated in the regulation of cerebral I/R injury via inhibiting Nrf2.

Down-regulating microRNA-20a regulates CDH1 to protect against cerebral ischemia/reperfusion injury in rats

Studies have extensively focused on the involvement of microRNAs (miRNAs) in cerebral ischemia/reperfusion (I/R) injury but not much on the specific role of miR-20a. Hence, this study is purposed to decipher whether miR-20a could regulate cadherin 1 (CDH1) to affect cerebral I/R injury in rats. Rat transient middle cerebral artery occlusion model (MCAO) was established. Rats were injected with lentiviral solution containing miR-20a inhibitor, or overexpressed CDH1 or combined depleted miR-20a and CDH1 to explore their roles in cerebral I/R injury. Oxidative stress-related factors, miR-20a, CDH1, nuclear factor-kappaB (NF-κB) and Nestin expression in brain tissues were detected by RT-qPCR and western blot assay. The target relation between miR-20a and CDH1 was predicted by online website and further confirmed by luciferase activity assay. In rats with cerebral I/R injury, increased miR-20a and decreased CDH1 were found in brain tissues. Reduction of miR-20a or elevation of CDH1 attenuated behavior function in MCAO rats. Inhibiting miR-20a or restoring CDH1 restrained oxidative stress, attenuated pathological damage of neurons, promoted neuron survival, and down-regulated NF-κB and Nestin expression in brain tissues of MCAO rats. CDH1 was determined to a target gene of miR-20a. This study elucidates that down-regulating miR-20a elevates CDH1 to protect neurons from cerebral I/R injury, which paves a new way for treatment of cerebral I/R injury.

Neuroprotective Effects of Celastrol on Transient Global Cerebral Ischemia Rats via Regulating HMGB1/NF-κB Signaling Pathway

Cerebral ischemia is a major cause of brain dysfunction, neuroinflammation and oxidative stress have been implicated in the pathophysiological process of cerebral ischemia/reperfusion injury. Celastrol is a potent inhibitor of inflammation and oxidative stress that has little toxicity. The present study was designed to evaluate whether celastrol has neuroprotective effects through anti-inflammatory and antioxidant actions, and to elucidate the possible involved mechanisms in transient global cerebral ischemia reperfusion (tGCI/R) rats. Celastrol (1, 2, or 4 mg/kg) was administrated intraperitoneally immediately after reperfusion and the effect of celastrol on reverting spatial learning and memory impairment was determined by Morris water maze (MWM) task. Inflammatory response and oxidative stress, hippocampal neuronal damage and glial activation, and HMGB1/NF-κB signaling pathway proteins were also examined. Our results indicated that celastrol dose-dependently reduced hippocampal and serum concentration of pro-inflammatory markers (TNF-α, IL-1β, and IL-6) and oxidative stress marker (MDA), whereas the anti-inflammatory marker IL-10 and antioxidant markers (GSH, SOD, and CAT) were increased significantly in celastrol treated tGCI/R rats. Celastrol alleviated apoptotic neuronal death, inhibited reactive glial activation and proliferation and improved ischemia-induced neurological deficits. Simultaneously, we found that mechanisms responsible for the neuroprotective effect of celastrol could be attributed to its anti-inflammatory and antioxidant actions via inhibiting HMGB1/NF-κB signaling pathway. These findings provide a proof of concept for the further validation that celastrol may be a superior candidate for the treatment of severe cerebral ischemic patients in clinical practice in the future.

Toll-like receptor 4 deficiency ameliorates β2-microglobulin induced age-related cognition decline due to neuroinflammation in mice

Toll-like receptor 4 (TLR4) is a crucial receptor in neuroinflammation and apoptotic neuronal death, and increasing evidences indicated that β2-microglobulin (B2M) is thought to be a major contributor to age-related cognitive decline. In present study, we designed to investigate the effects of TLR4 on B2M-induced age-related cognitive decline. Wild-type (WT) C57BL/6, TLR4 knockout (TLR4 -KO) mice and hippocampal neurons from the two type mice were respectively divided into two groups: (1) Veh group; (2) B2M-treated group. The behavioral responses of mice were measured using Morris Water Maze. Hippocampal neurogenesis and neuronal damage, inflammatory response, apoptosis, synaptic proteins and neurotrophic factors, and TLR4/MyD88/NF-κB signaling pathway proteins were examined using molecular biological or histopathological methods. The results showed that WT mice received B2M in the DG exhibited age-related cognitive declines, increased TLR4 mRNA expression and high levels of interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α) and apoptotic neuronal death in the hippocampus, which were partially attenuated in TLR4-KO mice. Moreover, in absence of TLR4, B2M treatment improved hippocampus neurogenesis and increased synaptic related proteins. Our cell experiments further demonstrated that deletion of TLR4 could significantly increase synaptic related protein, decrease neuroinflammatory fators, inhibited apoptotic neuronal death, and regulated MyD88/NF-κB signal pathway after B2M treatment. In summary, our results support the TLR4 contributes to B2M-induced age-related cognitive decline due to neuroinflammation and apoptosis through TLR4/MyD88/NF-κB signaling pathway via a modulation of hippocampal neurogenesis and synaptic function. This may provide an important neuroprotective mechanism for improving age-related cognitive decline.

Protective effects of Chrysin against memory impairment, cerebral hyperemia and oxidative stress after cerebral hypoperfusion and reperfusion in rats

Stroke is devastating and a leading cause of morbidity and mortality worldwide. Cerebral ischemia-reperfusion and its subsequent reactive hyperemia lead to neuronal damage in the hippocampus and cognitive decline. Chrysin (5, 7-dihydroxyflavone) is a well-known member of the flavonoid family with antioxidant and neuroprotective effects. Therefore, in the present study, the aim was to investigate whether chrysin will be able to recover the brain function caused by ischemia-reperfusion (I/R) in rats. Adult male Wistar rats (250-300 g) were randomly divided into five groups: and submitted to cerebral I/R or a sham surgery after three-weeks of pretreatment with chrysin (CH; 10, 30 and 100 mg/kg; P.O.) and/or normal saline containing %5 DMSO. Subsequently, sensorimotor scores, cognition, local cerebral blood flow, extracellular single unit, and histological parameters were evaluated following I/R. Hippocampus was used to evaluate biomarkers including: oxidative stress parameters and prostaglandin E2 (PGE2) using ELISA kits. Data showed that pretreatment with chrysin significantly improved sensorimotor signs, passive avoidance memory, and attenuated reactive hyperemia, and increased the average number of spikes/bin (p < 0.001). Furthermore, chrysin pre-treatment significantly decreased the levels of MDA, NO, and PGE2 (p < 0. 001), while increased the levels of GPX and the number of surviving cells in the hippocampal CA1 region (p < 0.01, p < 0.001; respectively). This study demonstrates that chrysin may have beneficial effects in the treatment of cognitive impairment and help recover the brain dysfunction induced by I/R.

Exposure to ambient dusty particulate matter impairs spatial memory and hippocampal LTP by increasing brain inflammation and oxidative stress in rats

OBJECTIVES

Exposure of healthy subjects to ambient airborne dusty particulate matter (PM) causes brain dysfunction. This study aimed to investigate the effect of sub-chronic inhalation of ambient PM in a designed special chamber to create factual dust storm (DS) conditions on spatial cognition, hippocampal long-term potentiation (LTP), inflammatory cytokines, and oxidative stress in the brain tissue.

METHODS

Adult male Wistar rats (250-300 g) were randomly divided into four groups: Sham (clean air, the concentration of dusty PM was <150 μg/m³), DS1 (200-500 μg/m³), DS2 (500-2000 μg/m³) and DS3 (2000-8000 μg/m³). Experimental rats were exposed to clean air or different sizes and concentrations of dust PM storm for four consecutive weeks (exposure was during 1-4, 8-11, 15-16 and 20-23 days, 30 min, twice daily) in a real-ambient dust exposure chamber. Subsequently, cognitive performance, hippocampal LTP, blood-brain barrier (BBB) permeability and brain edema of the animals evaluated. As well as, inflammatory cytokines and oxidative stress indexes in the brain tissue measured using ELISA assays.

RESULTS

Exposing to dust PM impaired spatial memory (p < 0.001), hippocampal LTP (p < 0.001). These disturbances were in line with the severe damage to respiratory system followed by disruption of BBB integrity (p < 0.001), increased brain edema (p < 0.001), inflammatory cytokines (p < 0.001) excretion and oxidative stress (p < 0.001) in brain tissue.

CONCLUSIONS

Our study showed that exposure to ambient dust PM increased brain edema and BBB permeability, induced memory impairment and hippocampal LTP deficiency by increasing the inflammatory responses and oxidative stress in the brain of the rats.

Calcitriol alleviates global cerebral ischemia-induced cognitive impairment by reducing apoptosis regulated by VDR/ERK signaling pathway in rat hippocampus

BACKGROUND

Vitamin D (VD) has important neuroprotective functions in the central nervous system. However, further exploration is still needed in the neuroprotective effects of VD monomer therapy on global cerebral ischemia (GCI) and its potential molecular mechanism.

OBJECTIVE

To investigate whether calcitriol, a biologically active metabolite of VD, could alleviate cognitive impairment induced by GCI via reducing cell apoptosis and activating the extracellular signal-regulated kinase (ERK) signaling pathway.

METHODS

A total of 145 adult male Sprague Dawley rats were randomly divided into five groups: Sham group (n = 45), GCI group (n = 45), calcitriol treatment group (GCI + calcitriol, n = 45), PD98059 treatment group (n = 5) and vehicle group (n = 5). Morris water maze test was used for evaluating spatial learning and memory functions. Neurological Severity Score and wet-dry weight method were applied to detect neurological deficits and brain water content, respectively. Hematoxylin and eosin staining, transmission electron microscopy, and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end-labeling staining were performed for evaluating the changes of hippocampal CA1 neurons. Immunocytochemistry, immunofluorescence chemistry, and western blot analysis were performed for evaluating the changes of related proteins.

RESULTS

Calcitriol significantly ameliorated the spatial learning and memory impairments, improved neurological function, attenuated brain edema, and improved the morphological defects in the CA1 area of the hippocampus. Besides, calcitriol reduced GCI-induced cell apoptosis and reversed the up-regulation of pro-apoptotic proteins (Caspase-3 and Bax) and the down-regulation of anti-apoptotic protein (Bcl-2). Furthermore, calcitriol also increased the expression of VD receptors (VDR) and activated the ERK signaling pathway. Moreover, the p-ERK1/2 inhibitor PD98059 reversed the effect of calcitriol on the expression of apoptosis-related proteins.

CONCLUSIONS

Calcitriol may have a protective effect against GCI-induced cognitive impairments via inhibition of apoptotic cascade by activating the VDR/ERK signaling pathway.

Electroacupuncture Alleviates Ischemic Brain Injury by Inhibiting the miR-223/NLRP3 Pathway

Background

Electroacupuncture (EA) has been commonly used to treat stroke in China. However, the underlying mechanism remains largely unknown. The present study investigated the neuroprotective effects of EA in middle cerebral artery occlusion (MCAO) rats and elucidated the possible anti-inflammatory mechanisms.

Material/Methods

In this study, modified neurological severity scoring (mNSS) was used to assess neurological deficits, and TTC staining and brain water content were measured to evaluate the degree of brain damage. HE staining, Nissl staining, and TUNEL staining were employed to evaluate apoptotic neuronal death. Molecular biological methods were used to measure the levels of miR-233, NLRP3, caspase-1, IL-1β, and IL-18 in the peri-infarct cortex.

Results

Our results showed that EA treatment significantly decreased the neurological deficit score and infarct volume of MCAO rats. The level of miR-223 was increased, while the levels of NLRP3, caspase-1, IL-1β, and IL-18 were decreased in the peri-infarct cortex of EA-treated MCAO rats. However, the neuroprotective effect of EA was partially blocked by antagomir-223.

Conclusions

These data suggest that EA treatment can alleviate neuroinflammation by inhibiting the miR-223/NLRP3 pathway, thus playing a neuroprotective role in MCAO in rats.

Cdh1 overexpression improves emotion and cognitive-related behaviors via regulating hippocampal neuroplasticity in global cerebral ischemia rats

Post-stroke survivors exhibited cognitive deficits and performed emotional impairment. However, the effect of global cerebral ischemia on standard behavioral measures of emotionality and underlying mechanism remain largely unknown. Our previous work identified that down-regulation of Cdh1 contributed to ischemic neuronal death in rat, thus we hypothesized that Cdh1 exerts a role in emotionality after cerebral ischemia, and we investigated the effect of Cdh1 overexpression on neurogenic behaviors and possible mechanisms in transient global cerebral ischemia reperfusion (tGCI/R) rats. A series of behavioral tests were used to evaluate emotion and cognitive related behaviors, and molecular biological techniques were employed to investigate hippocampal neuroplasticity. The results showed that tGCI/R rats displayed anxiety- and depression-like behaviors and a certain degree of cognitive impairment, and these abnormal behaviors accompanied with a loss of hippocampal synapses and dendritic spines, disruption of dendrite arborization and decline in the level of GAP-43, synaptophysin, synapsin and PSD-95. However, Cdh1 overexpression improved negative emotionality, ameliorated cognitive deficits, rescued hippocampal synapses loss, prevented dendritic network disorganization, and increased the level of synaptic-associated proteins after tGCI/R. Taken together, these findings suggest that Cdh1 overexpression exerts a neuroprotective effect by regulating hippocampal neuroplasticity thus improving negative emotionality and cognitive deficits after tGCI/R.

APC-Cdh1 Regulates Neuronal Apoptosis Through Modulating Glycolysis and Pentose-Phosphate Pathway After Oxygen-Glucose Deprivation and Reperfusion

Anaphase-promoting complex (APC) with its coactivator Cdh1 is required to maintain the postmitotic state of neurons via degradation of Cyclin B1, which aims to prevent aberrant cell cycle entry that causes neuronal apoptosis. Interestingly, evidence is accumulating that apart from the cell cycle, APC-Cdh1 also involves in neuronal metabolism via modulating the glycolysis promoting enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3). Here, we showed that under oxygen-glucose deprivation and reperfusion (OGD/R), APC-Cdh1 was decreased in primary cortical neurons. Likewise, the neurons exhibited enhanced glycolysis when oxygen supply was reestablished during reperfusion, which was termed as the "neuronal Warburg effect." In particular, the reperfused neurons showed elevated PFKFB3 expression in addition to a reduction in glucose 6-phosphate dehydrogenase (G6PD). Such changes directed neuronal glucose metabolism from pentose-phosphate pathway (PPP) to aerobic glycolysis compared to the normal neurons, resulting in increased ROS production and apoptosis during reperfusion. Pretreatment of neurons with Cdh1 expressing lentivirus before OGD could reverse this metabolic shift and attenuated ROS-induced apoptosis. However, the metabolism regulation and neuroprotection by Cdh1 under OGD/R condition could be blocked when co-transfecting neurons with Ken box-mut-PFKFB3 (which is APC-Cdh1 insensitive). Based on these data, we suggest that the Warburg effect may contribute to apoptotic mechanisms in neurons under OGD/R insult, and targeting Cdh1 may be a potential therapeutic strategy as both glucose metabolic regulator and apoptosis suppressor of neurons in brain injuries.