Genetic modification of miR-34a enhances efficacy of transplanted human dental pulp stem cells after ischemic stroke.

Human dental pulp stem cells (hDPSCs) promote recovery after ischemic stroke; however, the therapeutic efficacy is limited by the poor survival of transplanted cells. For in vitro experiments in the present study, we used oxygen-glucose deprivation/reoxygenation in hDPSCs to mimic cell damage induced by ischemia/reperfusion. We found that miRNA-34a-5p (miR-34a) was elevated under oxygen-glucose deprivation/reoxygenation conditions in hDPSCs. Inhibition of miR-34a facilitated the proliferation and antioxidant capacity and reduced the apoptosis of hDPSCs. Moreover, dual-luciferase reporter gene assay showed WNT1 and SIRT1 as the targets of miR-34a. In miR-34a knockdown cell lines, WNT1 suppression reduced cell proliferation, and SIRT1 suppression decreased the antioxidant capacity. Together, these results indicated that miR-34a regulates cell proliferation and antioxidant stress via targeting WNT1 and SIRT1, respectively. For in vivo experiments, we injected genetically modified hDPSCs (anti34a-hDPSCs) into the brains of mice. We found that anti34a-hDPSCs significantly inhibited apoptosis, reduced cerebral edema and cerebral infarct volume, and improved motor function in mice. This study provides new insights into the molecular mechanism of the cell proliferation and antioxidant capacity of hDPSCs, and suggests a potential gene that can be targeted to improve the survival rate and efficacy of transplanted hDPSCs in brain after ischemic stroke.

The eIF4A Inhibitor Silvestrol Blocks the Growth of Human Glioblastoma Cells by Inhibiting AKT/mTOR and ERK1/2 Signaling Pathway.

The most frequently identified central nervous system tumor in adults is glioblastoma multiforme (GBM). GBM prognosis remains poor despite multimodal treatment, i.e., surgery and radiation therapy with concurrent temozolomide-based chemotherapy. Silvestrol, an eIF4A inhibitor, has been demonstrated to be able to kill tumor cells in previous studies. In this study, it was found that silvestrol considerably attenuated the proliferative potential of U251 and U87 glioma cells and reduced expression of cyclin D1. In addition, silvestrol reduced the level of ERK1/2 and decreased the levels of AKT phosphorylation. Unfortunately, the effect of silvestrol in inhibiting GBM cells was greatly reduced with hypoxia, and the downregulation in AKT/mTOR and ERK1/2 were also rescued with an upregulation of HIF1α, which warranted further research. Taken together, silvestrol exerted antitumor effects in GBM cells by inhibiting the AKT/mTOR and ERK1/2 signaling cascades.

Dental pulp stem cell transplantation facilitates neuronal neuroprotection following cerebral ischemic stroke.

OBJECTIVES: This study aimed to identify and evaluate the intracranial transplantation of dental pulp stem cells (DPSCs) as a possible ischemic stroke therapy that mitigates neuronal death/apoptosis. MATERIALS AND METHODS: DPSCs were isolated from the impacted third molars of healthy volunteers and then intracranially injected at 24 h post-ischemic stroke to Sprague Dawley rats that had been subjected to 2 h of middle cerebral artery occlusion. Neurological functional deficits were assessed using the modified neurological severity score (mNSS), and cerebral edema was quantified using brain water content. Neuronal death/apoptosis was indicated by TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, NeuN immunofluorescence and immunohistochemistry, and Western blot analysis of the protein expression of anti-apoptotic indicator of Bcl-2 and apoptotic indicators of Bax and caspase 3. RESULTS: DPSC transplantation could ameliorate neurological dysfunction and brain edema, reduce infarct volume, decrease the percentage of TUNEL-positive nuclei, increase the number and percentage of NeuN-positive cells in ischemic penumbra, increase the ratio of Bcl-2 and Bax and down-regulate the production of caspase 3 in the cortical infarct zone. CONCLUSIONS: DPSC therapy via intracranial injection exerted remarkably neuroprotection mainly by inhibiting neuronal death/apoptosis.

Andrographolide Attenuates Blood-Brain Barrier Disruption, Neuronal Apoptosis, and Oxidative Stress Through Activation of Nrf2/HO-1 Signaling Pathway in Subarachnoid Hemorrhage.

Andrographolide (Andro), a diterpene of the labdane family extracted from the Asian plant Andrographis paniculata, is neuroprotective against stroke and Alzheimer's disease. However, whether Andro protected the brain against subarachnoid hemorrhage (SAH) was still unknown. Thus, we explored whether Andro attenuated blood-brain barrier (BBB) disruption and neuronal apoptosis and inhibited oxidative stress to protect the brain against SAH both in vitro and in vivo and detected underlying mechanisms of Andro's neuroprotective effects in the present study. Oxyhemoglobin (OxyHb)-treated neuronal PC12 cells were used as an in vitro model. An in vivo model was established using Sprague-Dawley rats. Moreover, we used an inhibitor of heme oxygenase-1 (HO-1) (ZnPPIX) in vitro and in vivo experiments to evaluate whether the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) cascade acted as one protective molecular mechanism of Andro against SAH. Our results revealed that, in vitro, Andro increased cell viability, inhibited apoptosis, and activated Nrf2/HO-1 cascade of neuronal PC12 cells treated with OxyHb. In vivo, Andro attenuated the neurological dysfunction, neuronal apoptosis, BBB disruption, brain edema, and oxidative stress and activated the Nrf2/HO-1 pathway. ZnPPIX reversed the effects of Andro in vitro and in vivo. Our research suggested that Andro alleviated BBB disruption, neuronal apoptosis, and oxidative stress in SAH, possibly via the Nrf2/HO-1 signaling pathway.

Classification and Characteristics of Mesenchymal Stem Cells and Its Potential Therapeutic Mechanisms and Applications against Ischemic Stroke.

Ischemic stroke is a serious cerebral disease that often induces death and long-term disability. As a currently available therapy for recanalization after ischemic stroke, thrombolysis, including intravenous thrombolysis and endovascular therapy, still cannot be applicable to all patients due to the narrow time window. Mesenchymal stem cell (MSC) transplantation therapy, which can trigger neuronal regeneration and repair, has been considered as a significant advance in treatment of ischemic stroke. MSC transplantation therapy has exhibited its potential to improve the neurological function in ischemic stroke. Our review describes the current progress and future perspective of MSC transplantation therapy in ischemic stroke treatment, including cell types, transplantation approaches, therapeutic mechanisms, and preliminary clinical trials of MSC transplantation, for providing us an update role of MSC transplantation in ischemic stroke treatment.

The neuroprotective effects of Insulin-Like Growth Factor 1 via the Hippo/YAP signaling pathway are mediated by the PI3K/AKT cascade following cerebral ischemia/reperfusion injury.

Insulin-like growth factor 1 (IGF-1) has neuroprotective actions, including vasodilatory, anti-inflammatory, and antithrombotic effects, following ischemic stroke. However, the molecular mechanisms underlying the neuroprotective effects of IGF-1 following ischemic stroke remain unknown. Therefore, in the present study, we investigated whether IGF-1 exerted its neuroprotective effects by regulating the Hippo/YAP signaling pathway, potentially via activation of the PI3K/AKT cascade, following ischemic stroke. In the in vitro study, we exposed cultured PC12 and SH-5YSY cells, and cortical primary neurons, to oxygen-glucose deprivation. Cell viability was measured using CCK-8 assay. In the in vivo study, Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Neurological function was assessed using a modified neurologic scoring system and the modified neurological severity score (mNSS) test, brain edema was detected by brain water content measurement, infarct volume was measured using triphenyltetrazolium chloride staining, and neuronal death and apoptosis were evaluated by TUNEL/NeuN double staining, HE and Nissl staining, and immunohistochemistry staining for NeuN. Finally, western blot analysis was used to measure the level of IGF-1 in vivo and levels of YAP/TAZ, PI3K and phosphorylated AKT (p-AKT) both in vitro and in vivo. IGF-1 induced activation of YAP/TAZ, which resulted in improved cell viability in vitro, and reduced neurological deficits, brain water content, neuronal death and apoptosis, and cerebral infarct volume in vivo. Notably, the neuroprotective effects of IGF-1 were blocked by an inhibitor of the PI3K/AKT cascade, LY294002. LY294002 treatment not only downregulated PI3K and p-AKT, but YAP/TAZ as well, leading to aggravation of neurological dysfunction and worsening of brain damage. Our findings indicate that the neuroprotective effects of IGF-1 are, at least in part mediated by upregulation of YAP/TAZ via activation of the PI3K/AKT cascade following cerebral ischemic stroke.

Characteristics and operation outcomes of neuro-oncology patients after COVID-19 pandemic - A case series.

BACKGROUND: COVID-19 has been spreading worldwide at hitherto unknown speed, and the treatment of neuro-oncology patients without COVID-19 has been greatly affected. METHODS: To compare the medical records and surgical results of surgical patients before and after the pandemic. We collected a total of 80 patients form April 2020 to May 2020 after pandemic and from April 2019 to May 2019 before pandemic. The patient's demographics, past medical history, comorbidities, imaging, pathology, laboratory teat, and Karnofsky Performance Score (KPS) were analyzed. RESULTS: The most common presenting symptom was intracranial hypertension and neurological deficit. Hypertension and diabetes were the most common comorbid diseases. The pre-operation KPS were 83.21 ± 15.60, 80 ± 14.77, 78.57 ± 12.83 and 74.14 ± 12.72, respectively. The post-operation KPS were 94.64 ± 8.65, 95.45 ± 6.56, 91.43 ± 10.82 and 84.21 ± 22.55, respectively. The tumor volume was larger and the midline shift distance was greater after the pandemic than before. For pathological grade, meningiomas were mostly grade I, while gliomas were mainly grade III and IV. CONCLUSION: Although affected by the COVID-19 pandemic, patients with glioma should be operated as soon as possible to obtain better surgical results, however, for patients with meningiomas, their operation can be postponed slightly when the patients are tolerable.

Tetramethylpyrazine attenuates blood-brain barrier disruption in ischemia/reperfusion injury through the JAK/STAT signaling pathway.

Tetramethylpyrazine (TMP) has been studied in depth and is widely used in the treatment of many kinds of diseases in China. However, whether it has neuroprotective effects on cerebral ischemia remains unclear. An ischemia/reperfusion (I/R) injury animal model was established via middle cerebral artery occlusion in this study. We set several different groups in which the rats were performed in different ways to explore the effects of TMP on blood-brainbarrier (BBB) disruption and determine whether TMP relieved BBB disruption through blocking the JAK/STAT signaling pathway. Our results showed that TMP could reduce the neurological functional loss, decrease the brain edema and BBB permeability, as well as increase the expression of tight junction proteins via inhibiting the activation of JAK/STAT signaling pathway. Overall, we demonstrated that TMP promoted neurological recovery after I/R injury via restoring the integrity and function of BBB.

Quantitative iTRAQ-based proteomic analysis of piperine protected cerebral ischemia/reperfusion injury in rat brain.

Piperine is the key bioactive factor in black pepper, and has been reported to alleviate cerebral ischemic injury. However, the mechanisms underlying its neuroprotective effects following cerebral ischemia remain unclear. In this study, rats were administered vehicle (dimethyl sulfoxide) or piperine, 20 mg/kg, daily for 14 days before focal cerebral artery occlusion. After occlusion for 2 h followed by reperfusion for 24 h. Histological examinations were used to assess whether piperine has a neuroprotective effect in the rat model of cerebral ischemia/reperfusion injury. The levels of proteins in the ischemic penumbra were evaluated by isobaric tags for relative and absolute quantitation-based proteomics. A total of 3687 proteins were identified, including 23 proteins that were highly significantly differentially expressed between the control and piperine groups. The proteomic findings were verified by immunofluorescence and western blot analysis. Interestingly, piperine administration downregulated a number of critical factors in the complement and coagulation cascades, including complement component 3, fibrinogen gamma chain, alpha-2-macroglobulin, and serpin family A member 1. Collectively, our findings suggest that the neuroprotective effects of piperine following cerebral ischemia/reperfusion injury are related to the regulation of the complement and coagulation cascades.

Hippo/YAP signaling pathway mitigates blood-brain barrier disruption after cerebral ischemia/reperfusion injury.

Ischemia/reperfusion (I/R) injuries commonly lead to breakdown of the blood-brain barrier (BBB). Restoration of the BBB can relieve neurologic damage caused by I/R injuries. The Hippo/YAP signaling pathway mediates cell proliferation, regulated cell death, and differentiation in various organisms and has been shown to participate in the restoration of the heart after I/R. In this study, we investigated whether the Hippo/YAP pathway plays a role in I/R injury in brain, especially in regard to I/R-induced BBB breakdown. The results of our study indicate that I/R injury led to an overall decrease in activity of the core proteins, YAP and TAZ, over a 24-h period. The most dramatic change was observed 1.5 h after reperfusion. In rats that underwent 1.5 h of reperfusion, intraperitoneal injection of YAP agonist dexamethasone activated YAP and TAZ and led to improved neurologic function, smaller brain infarct sizes, increased levels of tight junction proteins, decreased BBB permeability, decreased cerebral edema, and less apoptosis. Our results suggest that YAP exerts neuroprotective effects on the damaged brain that are likely related to restoration of the BBB.

Tissue Plasminogen Activator Causes Brain Microvascular Endothelial Cell Injury After Oxygen Glucose Deprivation by Inhibiting Sonic Hedgehog Signaling.

The thrombolytic activity of tissue plasminogen activator (tPA) has undisputed benefits. However, the documented neurotoxicity of tPA raises important issues. Currently, common treatments for stroke might not be optimum if exogenous tPA can pass through the blood-brain barrier and enter the brain, thus adding to the deleterious effects of tPA within the cerebral parenchyma. Here, we determined whether tPA could damage brain microvascular endothelial cells (BMECs) during cerebral ischemia. We showed that treatment of BMECs with tPA decreased trans-endothelial electrical resistance and cell proliferation, and blocked the cell cycle at the G0-G1 phase. In addition, the Sonic hedgehog (Shh) signaling pathway was involved in tPA-induced BMECs dysfunction. However, tPA-enhanced oxygen glucose deprivation-induced BMECs dysfunction was eliminated by Shh administration and the effects could be reversed by Shh inhibitors. Taken together, these results demonstrate that tPA administration might result in damage to the endothelial barrier owing to blocked Shh signaling pathway.

Rapamycin induces autophagy to alleviate acute kidney injury following cerebral ischemia and reperfusion via the mTORC1/ATG13/ULK1 signaling pathway.

Acute kidney injury (AKI) is a clinically common and severe complication of ischemia­reperfusion (I/R), associated with high morbidity and mortality rates, and prolonged hospitalization. Rapamycin is a type of macrolide, primarily used for anti­rejection therapy following organ transplantation and the treatment of autoimmune diseases. Rapamycin has been identified to exert a protective effect against AKI induced by renal I/R as an autophagy inducer. However, whether rapamycin preconditioning may relieve AKI following cerebral I/R (CIR) remains to be fully elucidated. The purpose of the present study was to investigate the effects of CIR on the renal system of rats and the role of rapamycin in AKI following CIR. In the present study, a CIR model was established in Sprague­Dawley rats via a 90­min period of middle cerebral artery occlusion and 24 h reperfusion, and pretreatment with an intraperitoneal injection of rapamycin (dosage: 1 mg/kg; 0.5 h) prior to CIR. The levels of serum creatinine and blood urea nitrogen (BUN), and the expression of inflammation­, apoptosis­ and autophagy­associated markers were subsequently measured. In addition to certain histopathological alterations to the kidney, it was identified that CIR significantly increased the levels of serum creatinine, BUN, tumor necrosis factor­α and interleukin­1ß, and significantly induced apoptosis and autophagy. It was observed that rapamycin induced autophagy through the mammalian target of rapamycin complex 1/autophagy­related 13/unc­51 like autophagy activating kinase 1 signaling pathway, and that rapamycin pre­treatment significantly improved renal function and alleviated renal tissue inflammation and cell apoptosis in rats following CIR. In conclusion, the results suggested that rapamycin may alleviate AKI following CIR via the induction of autophagy.