ErbB4 protects against neuronal apoptosis via activation of YAP/PIK3CB signaling pathway in a rat model of subarachnoid hemorrhage

The case for neuregulin-1 as a clinical treatment for stroke

Ischemic stroke is the leading cause of serious long-term disability and the 5th leading cause of death in the United States. Revascularization of the occluded cerebral artery, either by thrombolysis or endovascular thrombectomy, is the only effective, clinically-approved stroke therapy. Several potentially neuroprotective agents, including glutamate antagonists, anti-inflammatory compounds and free radical scavenging agents were shown to be effective neuroprotectants in preclinical animal models of brain ischemia. However, these compounds did not demonstrate efficacy in clinical trials with human patients following stroke. Proposed reasons for the translational failure include an insufficient understanding on the cellular and molecular pathophysiology of ischemic stroke, lack of alignment between preclinical and clinical studies and inappropriate design of clinical trials based on the preclinical findings. Therefore, novel neuroprotective treatments must be developed based on a clearer understanding of the complex spatiotemporal mechanisms of ischemic stroke and with proper clinical trial design based on the preclinical findings from specific animal models of stroke. We and others have demonstrated the clinical potential for neuregulin-1 (NRG-1) in preclinical stroke studies. NRG-1 significantly reduced ischemia-induced neuronal death, neuroinflammation and oxidative stress in rodent stroke models with a therapeutic window of >13 h. Clinically, NRG-1 was shown to be safe in human patients and improved cardiac function in multisite phase II studies for heart failure. This review summarizes previous stroke clinical candidates and provides evidence that NRG-1 represents a novel, safe, neuroprotective strategy that has potential therapeutic value in treating individuals after acute ischemic stroke.

Ruscogenin ameliorates dasatinib-induced intestinal barrier dysfunction via ErbB4/YAP and ROCK/MLC pathways

Dasatinib is effective in the treatment of chronic and acute myeloid leukemia, which could cause the side effect of gastrointestinal bleeding by overdose or longtime use. Ruscogenin (RUS) from the traditional Chinese medicine Ophiopogon japonicas could protect endothelial microvascular barrier function. In this study, the therapeutic effect and underlying mechanisms of RUS were investigated on intestinal barrier dysfunction induced by dasatinib. Male C57BL/6 J mice were given three doses of dasatinib (70, 140, 210 mg/kg, ig) and RUS (3, 10, 30 μg/kg, ip) to explore the effect of dasatinib on intestinal barrier and the intervention of RUS. It was proved that dasatinib could reduce intestinal blood flow, inhibit phosphorylation of EGFR family member v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4 (ErbB4)/YES-associated protein (YAP) and activation of Rho-associated coiled coil-containing protein kinase (ROCK)/phosphorylation of (myosin light chain) MLC. RUS could significantly increase intestinal blood flow, improve intestinal injury, reduce Evans blue leakage and serum content of FITC-dextran 4 kDa, and increase the expression of connexin (ZO-1, Occludin and VE-cadherin). Meanwhile, the in vitro effect of RUS (0.01, 0.1, 1 μM) on the dysfunction of the endothelial barrier was observed in dasatinib (150 nM)-pretreated HUVECs. The results showed that RUS suppressed dasatinib-induced the leakage of Evans blue, and degradation of F-actin and connexin. Furthermore, RUS could significantly increase the phosphorylation of ErbB4 at Tyr1284 site and YAP at Ser397 site, and inhibit ROCK expression and phosphorylation of MLC at Ser19 site in vivo and in vitro. In conclusion, the present research proved that RUS could suppress the side effects of dasatinib-induced intestinal barrier dysfunction by regulating ErbB4/YAP and ROCK/MLC pathways.

The mechanism and relevant mediators associated with neuronal apoptosis and potential therapeutic targets in subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a dominant cause of death and disability worldwide. A sharp increase in intracranial pressure after SAH leads to a reduction in cerebral perfusion and insufficient blood supply for neurons, which subsequently promotes a series of pathophysiological responses leading to neuronal death. Many previous experimental studies have reported that excitotoxicity, mitochondrial death pathways, the release of free radicals, protein misfolding, apoptosis, necrosis, autophagy, and inflammation are involved solely or in combination in this disorder. Among them, irreversible neuronal apoptosis plays a key role in both short- and long-term prognoses after SAH. Neuronal apoptosis occurs through multiple pathways including extrinsic, mitochondrial, endoplasmic reticulum, p53 and oxidative stress. Meanwhile, a large number of blood contents enter the subarachnoid space after SAH, and the secondary metabolites, including oxygenated hemoglobin and heme, further aggravate the destruction of the blood-brain barrier and vasogenic and cytotoxic brain edema, causing early brain injury and delayed cerebral ischemia, and ultimately increasing neuronal apoptosis. Even there is no clear and effective therapeutic strategy for SAH thus far, but by understanding apoptosis, we might excavate new ideas and approaches, as targeting the upstream and downstream molecules of apoptosis-related pathways shows promise in the treatment of SAH. In this review, we summarize the existing evidence on molecules and related drugs or molecules involved in the apoptotic pathway after SAH, which provides a possible target or new strategy for the treatment of SAH.

Inhibition of Prostaglandin E2 Receptor EP3 Attenuates Oxidative Stress and Neuronal Apoptosis Partially by Modulating p38MAPK/FOXO3/Mul1/Mfn2 Pathway after Subarachnoid Hemorrhage in Rats

Oxidative stress and neuronal apoptosis contribute to pathological processes of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Previous studies demonstrated that the inhibition of prostaglandin E2 receptor EP3 suppressed oxidative stress and apoptotic effects after Alzheimer's disease and intracerebral hemorrhage. This study is aimed at investigating the antioxidative stress and antiapoptotic effect of EP3 inhibition and the underlying mechanisms in a rat mode of SAH. A total of 263 Sprague-Dawley male rats were used. SAH was induced by endovascular perforation. Selective EP3 antagonist L798106 was administered intranasally at 1 h, 25 h, and 49 h after SAH induction. EP3 knockout CRISPR and FOXO3 activation CRISPR were administered intracerebroventricularly at 48 h prior to SAH, while selective EP3 agonist sulprostone was administered at 1 h prior to SAH. SAH grade, neurological deficits, western blots, immunofluorescence staining, Fluoro-Jade C staining, TUNEL staining, 8-OHdG staining, and Nissl staining were conducted after SAH. The expression of endogenous PGES2 increased and peaked at 12 h while the expression of EP1, EP2, EP3, EP4, and Mul1 increased and peaked at 24 h in the ipsilateral brain after SAH. EP3 was expressed mainly in neurons. The inhibition of EP3 with L798106 or EP3 KO CRISPR ameliorated the neurological impairments, brain tissue oxidative stress, and neuronal apoptosis after SAH. To examine potential downstream mediators of EP3, we examined the effect of the increased expression of activated FOXO3 following the administration of FOXO3 activation CRISPR. Mechanism studies demonstrated that L798106 treatment significantly decreased the expression of EP3, p-p38, p-FOXO3, Mul1, 4-HNE, Bax, and cleaved caspase-3 but upregulated the expression of Mfn2 and Bcl-2 in SAH rats. EP3 agonist sulprostone or FOXO3 activation CRISPR abolished the neuroprotective effects of L798106 and its regulation on expression of p38MAPK/FOXO3/Mul1/Mfn2 in the ipsilateral brain after SAH. In conclusion, the inhibition of EP3 by L798106 attenuated oxidative stress and neuronal apoptosis partly through p38MAPK/FOXO3/Mul1/Mfn2 pathway post-SAH in rats. EP3 may serve as a potential therapeutic target for SAH patients.

ErbB4 in the brain: Focus on high grade glioma

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases (RTKs) consists of EGFR, ErbB2, ErbB3, and ErbB4. These receptors play key roles in cell proliferation, angiogenesis, cell migration, and in some cases, tumor promotion. ErbB4 is a unique member of the EGFR family, implicated not only in pro-tumorigenic mechanisms, such as cell proliferation and migration, but also in anti-tumorigenic activities, including cell differentiation and apoptosis. ErbB4 is differentially expressed in a wide variety of tissues, and interestingly, as different isoforms that result in vastly different signalling outcomes. Most studies have either ignored the presence of these isoforms or used overexpression models that may mask the true function of ErbB4. ErbB4 is widely expressed throughout the body with significant expression in skeletal tissue, mammary glands, heart, and brain. Knockout models have demonstrated embryonic lethality due to disrupted heart and brain development. Despite high expression in the brain and a critical role in brain development, remarkably little is known about the potential signalling activity of ErbB4 in brain cancer.This review focuses on the unique biology of ErbB4 in the brain, and in particular, highlights brain cancer research findings. We end the review with a focus on high grade gliomas, primarily glioblastoma, a disease that has been shown to involve EGFR and its mutant forms. The role of the different ErbB4 isotypes in high grade gliomas is still unclear and future research will hopefully shed some light on this question.

The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments

The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.

Circular RNA circ_0001162 promotes cell proliferation and invasion of glioma via the miR-936/ERBB4 axis

The biological modulatory roles of many circular RNAs (circRNAs) have been validated in glioma. The current study was designed to research the functional mechanism of circ_0001162 in glioma progression. The quantitative real-time polymerase chain reaction (qRT-PCR) was used for assaying the levels of circ_0001162 and microRNA-936 (miR-936). Cell proliferation and colony formation abilities were evaluated via 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) and colony formation assay, respectively. Transwell assay was applied to assess cell migration and invasion. The impact of circ_0001162 on glioma growth in vivo was performed using xenograft tumor assay. The target binding was affirmed via the dual-luciferase reporter and RNA pull-down assays. All protein expression levels were examined via Western blot. Circ_0001162 was an overexpressed circRNA in glioma. Circ_0001162 promoted glioma cell proliferation, colony formation, migration and invasion in vitro. Tumorigenesis of glioma in vivo was also enhanced by circ_0001162. Circ_0001162 could directly target miR-936 and the biological function of circ_0001162 in glioma was related to the inhibition of miR-936. ErbB2 receptor tyrosine kinase 4 (ERBB4) was a direct target of miR-936. Additionally, miR-936 inhibited the glioma development via targeting ERBB4. The miR-936/ERBB4 axis was responsible for the oncogenic role of circ_0001162 in glioma. The effects of circ_0001162 on glioma cells were also associated with the positive regulation of ERBB4. These results indicated that circ_0001162 contributed to the glioma progression via regulating the miR-936/ERBB4 axis, which laid a foundation for the pathomechanism and molecular treatment of glioma.

T0901317, an Agonist of Liver X Receptors, Attenuates Neuronal Apoptosis in Early Brain Injury after Subarachnoid Hemorrhage in Rats via Liver X Receptors/Interferon Regulatory Factor/P53 Upregulated Modulator of Apoptosis/Dynamin-1-Like Protein Pathway

Methods

Subarachnoid hemorrhage (SAH) models of Sprague-Dawley rats were established with perforation method. T0901317 was injected intraperitoneally 1-hour post-SAH. GSK2033, an inhibitor of LXRs, and interferon regulatory factor (IRF-1) CRISPR activation were injected intracerebroventricularly to evaluate potential signaling pathway. The severity of SAH, neurobehavior test in both short- and long-term and apoptosis was measured with Western blot and immunofluorescence staining.

Results

Expression of LXR-α and IRF-1 increased and peaked at 24 h post-SAH, while LXR-β remained unaffected in SAH+vehicle group compared with Sham group. Post-SAH T0901317 treatment attenuated neuronal impairments in both short- and long-term and decreased neuronal apoptosis, the expression of IRF-1, P53 upregulated modulator of apoptosis (PUMA), dynamin-1-like protein (Drp1), Bcl-2-associated X protein (Bax) and cleaved caspase-3, and increasing B-cell lymphoma 2 (Bcl-2) at 24 h from modeling. GSK2033 inhibited LXRs and reversed T0901317's neuroprotective effects. IRF-1 CRISPR activation upregulated the expression of IRF-1 and abolished the treatment effects of T0901317.

Conclusion

T0901317 attenuated neuronal apoptosis via LXRs/IRF-1/PUMA/Drp1 pathway in SAH rats.

Transcriptional co-activators YAP/TAZ: Potential therapeutic targets for metastatic breast cancer

Breast cancer is the most commonly diagnosed cancer among women. Although routine and targeted therapies have improved the survival rate, there are still considerable challenges in the treatment of breast cancer. Metastasis is the leading cause of death in patients diagnosed with breast cancer. Yes-associated protein (YAP) and/or PDZ binding motif (TAZ) are usually abnormally activated in breast cancer leading to a variety of effects on tumour promotion, such as epithelial-mesenchymal transition, cancer stem cell production and drug-resistance. The abnormal activation of YAP/TAZ can affect metastasis-related processes and promote cancer progression and metastasis by interacting with some metastasis-related factors and pathways. In this article, we summarise the evidence that YAP/TAZ regulates breast cancer metastasis, its post-translational modification mechanisms, and the latest advances in the treatment of YAP/TAZ-related breast cancer metastasis, besides providing a new strategy of YAP/TAZ-based treatment of human breast cancer.

Ascorbic acid promotes the reproductive function of porcine immature Sertoli cells through transcriptome reprogramming

Vitamin C (ascorbic acid, AA) can regulate antioxidation and affect many cellular processes. However, the effect of AA on the reproduction of male animals remains less explored. Here, we showed that by supplementing exogenous AA to porcine immature Sertoli cells (iSCs), AA could promote the proliferation, suppress apoptosis, and decrease the global nucleic acid methylation (5 mC and m⁶A) levels of iSCs. After we profiled mRNA and long non-coding RNA (lncRNA) expression by transcriptome sequencing on iSCs (treated by 250 μM AA for 36 h), 1232 mRNAs and 937 lncRNAs were identified to be differentially expressed (DE). Gene enrichment analysis found multiple significantly enriched biological pathways, including oxidoreductase activity, cell proliferation and apoptosis, regulation of hormone level, regulation of catalytic activity, developmental process, ATP metabolism and reproductive process. Specifically, for the reproductive process, 49 up- and 36 down-regulated DE mRNAs (including highly expressed genes, such as Tfcp2l1, Hmgcs1, Mmp7, Fndc3a, and Zfp36l1) are involved. Moreover, AA supplementation could promote the secretion of anti-müllerian hormone, inhibin B and lactate, and enhance the activity of lactate dehydrogenase as well. Taken together, AA could promote the reproductive function of pig iSCs, potentially through reprogramming the global transcriptome, and elevating hormone secretion and metabolite production.

•

AA could promote the proliferation, suppress apoptosis, and decrease the global nucleic acid mthylation levels of iSCs.

•

AA treatment changed mRNA and lncRNA profiles of iSCs.

•

AA treatment significantly disturbed the expression of mRNAs (such as Tfcp2l1, Hmgcs1, Mmp7, Fndc3a, and Zfp36l1) involved in reproductive process.

•

AA supplement could promote the secretion of anti-mullerian hormone, inhibin B and lactate, and the activity of lactate dehydrogenase as well.

The Effects of YAP and Its Related Mechanisms in Central Nervous System Diseases

Yes-associated protein (YAP) is a key effector downstream of the Hippo signaling pathway and plays an important role in the development of the physiology and pathology of the central nervous system (CNS), especially regulating cell proliferation, differentiation, migration, and apoptosis. However, the roles and underlying mechanisms of YAP in CNS diseases are still puzzling. Here, this review will systematically and comprehensively summarize the biological feature, pathological role, and underlying mechanisms of YAP in normal and pathologic CNS, which aims to provide insights into the potential molecular targets and new therapeutic strategies for CNS diseases.

Erbb4 Is Required for Cerebellar Developmentand Malignant Phenotype of Medulloblastoma

Medulloblastoma is the most common and malignant pediatric brain tumor in childhood. It originates from dysregulation of cerebellar development, due to an excessive proliferation of cerebellar granule neuron precursor cells (CGNPs). The underlying molecular mechanisms, except for the role of SHH and WNT pathways, remain largely unknown. ERBB4 is a tyrosine kinase receptor whose activity in cancer is tissue dependent. In this study, we characterized the role of ERBB4 during cerebellum development and medulloblastoma progression paying particular interests to its role in CGNPs and medulloblastoma stem cells (MBSCs). Our results show that ERBB4 is expressed in the CGNPs during cerebellum development where it plays a critical role in migration, apoptosis and differentiation. Similarly, it is enriched in the population of MBSCs, where also controls those critical processes, as well as self-renewal and tumor initiation for medulloblastoma progression. These results are translated to clinical samples where high levels of ERBB4 correlate with poor outcome in Group 4 and all medulloblastomas groups. Transcriptomic analysis identified critical processes and pathways altered in cells with knock-down of ERBB4. These results highlight the impact and underlying mechanisms of ERBB4 in critical processes during cerebellum development and medulloblastoma.

Activation of Melanocortin 1 Receptor Attenuates Early Brain Injury in a Rat Model of Subarachnoid Hemorrhage viathe Suppression of Neuroinflammation through AMPK/TBK1/NF-κB Pathway in Rats

Neuroinflammation plays a vital role in early brain injury (EBI) following subarachnoid hemorrhage (SAH). The hypothesis of this study was that activation of melanocortin 1 receptor (MC1R) with BMS-470539 attenuates EBI by suppression of neuroinflammation after SAH. We utilized BMS-470539, MSG-606, and MRT-68601 to verify the neuroprotective effects of MC1R. We evaluated brain water content, short-term and long-term neurobehavior after SAH. Western blotting and immunofluorescence staining were utilized to assess the changes of protein levels. The results of western blotting suggested that the expressions of MC1R, phosphorylated-adenosine monophosphate-activated protein kinase (p-AMPK), and phosphorylated-TANK binding kinase 1 (p-TBK1) were increased and reached their peak points at 24 h following SAH. Moreover, BMS-470539 treatment notably attenuated neurological deficits caused by SAH, and also notably improved long-term spatial learning and memory abilities after SAH. The underlying mechanisms of the neuroprotection of BMS-470539 involved the suppression of microglia activation, promotion of CD206+ microglia transformation and reduction of neutrophil infiltration by increasing the levels of p-AMPK and p-TBK1 while decreasing the levels of NF-κB, IL-1β, and TNFα. The neuroprotective effects of BMS-470539 were significantly abolished by MSG-606 and MRT-68601. The activation of MC1R with BMS-470539 notably attenuates EBI after SAH by suppression of microglial activation and neutrophil infiltration via the AMPK/TBK1/NF-κB signaling pathway.

Activation of TGR5 with INT-777 attenuates oxidative stress and neuronal apoptosis via cAMP/PKCε/ALDH2 pathway after subarachnoid hemorrhage in rats

BACKGROUND

Oxidative stress and neuronal apoptosis play important roles in the pathogenesis of early brain injury (EBI) after subarachnoid hemorrhage (SAH). The activation of TGR5, a novel membrane-bound bile acid receptor, possesses anti-oxidative stress and anti-apoptotic effects in hepatobiliary disease and kidney disease. The present study aimed to explore the neuroprotective effect of TGR5 activation against EBI after SAH and the potential underlying mechanisms.

METHODS

The endovascular perforation model of SAH was performed on 199 Sprague Dawley rats to investigate the beneficial effects of TGR5 activation after SAH. INT-777, a specific synthetic TGR5 agonist, was administered intranasally at 1 h after SAH induction. TGR5 CRISPR and ALDH2 CRISPR were administered intracerebroventricularly at 48 h before SAH to illuminate potential mechanisms. The SAH grade, short-term and long-term neurobehavioral tests, TUNEL staining, Fluoro-Jade C staining, Nissl staining, immunofluorescence staining, and western blots were performed at 24 h after SAH.

RESULTS

The expressions of endogenous TGR5 and ALDH2 gradually increased and peaked at 24 h after SAH. TGR5 was expressed primarily in neurons, as well as in astrocytes and microglia. The activation of TGR5 with INT-777 significantly improved the short-term and long-term neurological deficits, accompanied by reduced the oxidative stress and neuronal apoptosis at 24 h after SAH. Moreover, INT-777 treatment significantly increased the expressions of TGR5, cAMP, phosphorylated PKCε, ALDH2, HO-1, and Bcl-2, while downregulated the expressions of 4-HNE, Bax, and Cleaved Caspase-3. TGR5 CRISPR and ALDH2 CRISPR abolished the neuroprotective effects of TGR5 activation after SAH.

CONCLUSIONS

In summary, the activation of TGR5 with INT-777 attenuated oxidative stress and neuronal apoptosis via the cAMP/PKCε/ALDH2 signaling pathway after SAH in rats. Furthermore, TGR5 may serve as a novel therapeutic target to ameliorate EBI after SAH.

Neuroprotection by Exogenous and Endogenous Neuregulin-1 in Mouse Models of Focal Ischemic Stroke

Identifying novel neuroprotectants that can halt or reverse the neurological effects of stroke is of interest to both clinicians and scientists. We and others previously showed the pre-clinical neuroprotective efficacy of neuregulin-1 (NRG-1) in rats following focal brain ischemia. In this study, we examined neuroprotection by exogenous and endogenous NRG-1 using a mouse model of ischemic stroke. C57BL6 mice were subjected to middle cerebral artery occlusion (MCAO) followed by reperfusion. NRG-1 or vehicle was infused intra-arterially (i.a.) or intravenously (i.v.) after MCAO and before the onset of reperfusion. NRG-1 treatment (16 μg/kg; i.a.) reduced cerebral cortical infarct volume by 72% in mice when delivered post-ischemia. NRG-1 also inhibited neuronal injury as measured by Fluoro Jade B labeling and rescued NeuN immunoreactivity in neurons. Neuroprotection by NRG-1 was also observed in mice when administered i.v. (100 μg/kg) in both male and female mice. We investigated whether endogenous NRG-1 was neuroprotective using male and female heterozygous NRG-1 knockout mice (NRG-1+/-) compared with wild-type mice (WT) littermates. NRG-1+/- and WT mice were subjected to MCAO for 45 min, and infarct size was measured 24 h following MCAO. NRG-1+/- mice displayed a sixfold increase in cortical infarct size compared with WT mice. These results demonstrate that NRG-1 treatment mitigates neuronal damage following cerebral ischemia. We further showed that reduced endogenous NRG-1 results in exacerbated neuronal injury in vivo. These findings suggest that NRG-1 represents a promising therapy to treat stroke in human patients.

Sodium/Hydrogen Exchanger 1 Participates in Early Brain Injury after Subarachnoid Hemorrhage both in vivo and in vitro via Promoting Neuronal Apoptosis

Sodium/hydrogen exchanger 1 (NHE1) plays an essential role in maintaining intracellular pH (pHi) homeostasis in the central nervous system (CNS) under physiological conditions, and it is also associated with neuronal death and intracellular Na⁺ and Ca²⁺ overload induced by cerebral ischemia. However, its roles and underlying mechanisms in early brain injury (EBI) induced by subarachnoid hemorrhage (SAH) have not been fully explored. In this research, a SAH model in adult male rat was established through injecting autologous arterial blood into prechiasmatic cistern. Meanwhile, primary cultured cortical neurons of rat treated with 5 μM oxygen hemoglobin (OxyHb) for 24 h were applied to mimic SAH in vitro. We find that the protein levels of NHE1 are significantly increased in brain tissues of rats after SAH. Downregulation of NHE1 by HOE642 (a specific chemical inhibitor of NHE1) and genetic-knockdown can effectively alleviate behavioral and cognitive dysfunction, brain edema, blood-brain barrier (BBB) injury, inflammatory reactions, oxidative stress, neurondegeneration, and neuronal apoptosis, all of which are involved in EBI following SAH. However, upregulation of NHE1 by genetic-overexpression can produce opposite effects. Additionally, inhibiting NHE1 significantly attenuates OxyHb-induced neuronal apoptosis in vitro and reduces interaction of NHE1 and CHP1 both in vivo and in vitro. Collectively, we can conclude that NHE1 participates in EBI induced by SAH through mediating inflammation, oxidative stress, behavioral and cognitive dysfunction, BBB injury, brain edema, and promoting neuronal degeneration and apoptosis.

Genome-wide identification of the interactions between key genes and pathways provide new insights into the toxicity of bisphenol F and S during early development in zebrafish

Bisphenol F (BPF) and bisphenol S (BPS) have been widely used as alternatives to bisphenol A (BPA). With their increasing use, BPF and BPS have also been released into the environment; thus, their potential risks to aquatic organisms and humans are drawing attention. The objective of this study was to identify the interactions between key pathways and hub genes in zebrafish following BPF and BPS exposure, and to evaluate the potential risks to human health. We identified three key pathways using KEGG over-representation test and Gene Set Enrichment Analysis (GSEA): 'Necroptosis,' 'Adipocytokine signaling pathway,' and 'C-type lectin receptor signaling pathway.' Moreover, three hub genes (mst1ra, prkcdb, and pik3cb) and detailed interactions among the pathways were examined by the analyses of PPI network, subcellular location, and shortest-pathway. Surprisingly, all three pathways were strongly associated with a potential risk of cancer, as reported previously. In addition, the results of KOBAS shown in 'Pathways in Cancer' and 'Cancers' belong to the top 10 terms in pathway enrichment analyses using genes related to BPF or BPS in human, as was found using GenCLiP. Moreover, the Kaplan-Meier survival analysis was performed using homologenes (MST1R, PIK3CB and PRKCD) of hub genes in human to evaluate whether exposure to bisphenols may adversely affect breast cancer. Taken together, these studies demonstrate the potential carcinogenicity of BPF and BPS. To our knowledge, this is the first study on three overlapping key pathways and three hub genes to investigate BPF and BPS exposure-related mechanisms and subsequent interactions in zebrafish.

ErbB4 Preserves Blood-Brain Barrier Integrity via the YAP/PIK3CB Pathway After Subarachnoid Hemorrhage in Rats

Studies have suggested that blood-brain barrier (BBB) disruption contributes to the pathogenesis of early brain injury after subarachnoid haemorrhage (SAH). Activation of the receptor tyrosine kinase ErbB4 can cause intramembrane proteolysis and release a soluble intracellular domain (ICD) that modulates transcription in the nucleus. This study was carried out to investigate the potential roles of ErbB4 in preserving BBB integrity after experimental SAH, as well as the underlying mechanisms of its protective effects. Endovascular perforation was used to prepare a rat SAH model. The SAH grade, neurological score, brain edema and BBB permeability were evaluated after surgery. Immunohistochemistry was used to determine the localization of ErbB4 and yes-associated protein (YAP). ErbB4 activator Nrg1 isoform β1 (Nrg1β1), Specific ErbB4 siRNA, YAP siRNA and PIK3CB specific inhibitor TGX 221 were used to manipulate the proposed pathway. The expression levels of ErbB4 ICD and YAP were markly increased after SAH. Double immunohistochemistry labeling showed that ErbB4 and YAP were expressed in endothelial cells and neurons. Activation of ErbB4 by Nrg1β1 (dosage 150 ng/kg) treatment promoted the neurobehavioral deficit, alleviated the brain water content and reduced albumin leakage 24 and 72 h after SAH. ErbB4 activation significantly promoted YAP and PIK3CB activity and increased the expression of tight junction proteins Occludin and Claudin-5. Depletion of ErbB4 aggravated neurological impairment and BBB disruption after SAH. The beneficial effects of ErbB4 activation were abolished by YAP small-interfering RNA and specific PIK3CB inhibitor. Activation of ErbB4 improved neurological performance after SAH through the YAP/PIK3CB signaling pathway, this neuroprotective effects may associated with BBB maintenance.

Propofol Protects Hippocampal Neurons from Hypoxia-Reoxygenation Injury by Decreasing Calcineurin-Induced Calcium Overload and Activating YAP Signaling

Objectives

Propofol is a popular anesthetic drug that is neuroprotective. However, the mechanisms of propofol for hippocampal neuroprotection remain elusive. This study is aimed at investigating the neuroprotective effect and mechanism of propofol in hippocampal neurons exposed to ischemia-reperfusion (I/R) injury.

Methods

Hypoxia-reoxygenated (H/R) HT-22 cells were used to mimic I/R injury of the hippocampus in vitro. An MTT assay was used to determine cell viability. Cell apoptosis was detected by a TUNEL assay and a flow cytometry cell apoptosis assay. Expression levels of proteins were measured by Western blotting. Intracellular calcium was assessed by Fura-2/AM staining. Flow cytometry was used to determine the mitochondrial membrane potential (MMP). Coimmunoprecipitation was used to evaluate the stability of the FKBP-RyR complex. Calcineurin enzymatic activity was measured with a colorimetric method. YAP nuclear translocation was tested by immunofluorescence staining.

Results

H/R induced HT-22 cell viability depression, and apoptosis was reversed by propofol treatment. Propofol could alleviate H/R-induced intracellular calcium accumulation and MMP loss by inhibiting calcineurin activity and FKBP12.6-RyR disassociation in a concentration-dependent manner. In addition, YAP expression was crucial for propofol to protect HT-22 cell apoptosis from H/R injury. Propofol could activate YAP through dephosphorylation. Activated YAP stimulated the transcription of the Bcl2 gene, which promotes cellular survival. Our data also demonstrated that propofol activated YAP through the RhoA-Lats1 pathway without large G proteins or MST involvement. In addition, we showed that there was no interaction between calcineurin signaling and YAP activation in HT-22 cells.

Conclusions

Propofol protected hippocampal neurons from I/R injury through two independent signaling pathways, including the calcineurin/FKBP12.6-RyR/calcium overload pathway and the RhoA/Lats1/YAP/Bcl-2 pathway.

VEGF Signaling in Neurological Disorders

Vascular endothelial growth factor (VEGF) is a potent growth factor playing diverse roles in vasculogenesis and angiogenesis. In the brain, VEGF mediates angiogenesis, neural migration and neuroprotection. As a permeability factor, excessive VEGF disrupts intracellular barriers, increases leakage of the choroid plexus endothelia, evokes edema, and activates the inflammatory pathway. Recently, we discovered that a heparin binding epidermal growth factor like growth factor (HB-EGF)—a class of EGF receptor (EGFR) family ligands—contributes to the development of hydrocephalus with subarachnoid hemorrhage through activation of VEGF signaling. The objective of this review is to entail a recent update on causes of death due to neurological disorders involving cerebrovascular and age-related neurological conditions and to understand the mechanism by which angiogenesis-dependent pathological events can be treated with VEGF antagonisms. The Global Burden of Disease study indicates that cancer and cardiovascular disease including ischemic and hemorrhagic stroke are two leading causes of death worldwide. The literature suggests that VEGF signaling in ischemic brains highlights the importance of concentration, timing, and alternate route of modulating VEGF signaling pathway. Molecular targets distinguishing two distinct pathways of VEGF signaling may provide novel therapies for the treatment of neurological disorders and for maintaining lower mortality due to these conditions.