Effects and Mechanism of Action of Neonatal Versus Adult Astrocytes on Neural Stem Cell Proliferation After Traumatic Brain Injury.

Due to the limited capacity of brain tissue to self-regenerate after traumatic brain injury (TBI), the mobilization of endogenous neural stem cells (NSCs) is a popular research topic. In the clinic, the neurogenic abilities of adults versus neonates vary greatly, which is likely related to functional differences in NSCs. Recent studies have demonstrated that the molecules secreted from astrocytes play important roles in NSC fate determination. In this study, conditioned media (CM) derived from neonatal or adult rat astrocytes, which were unstimulated or stimulated by lipopolysaccharide (LPS), were prepared to treat NSCs. Our results revealed that neonatal rat astrocytes can significantly promote the proliferation of NSCs, compared with adult rat astrocytes, regardless of whether or not they were stimulated by LPS. Furthermore, we used mass spectrometry to detect the constituents of the CM from each group. We analyzed and screened for a protein, Tenascin-C (TNC), which was highly expressed in the neonatal group but poorly expressed in the adult group. We found that TNC can bind to the NSC surface epidermal growth factor receptor and promote proliferation through the PI3K-AKT pathway in vitro. Additionally, we confirmed in vivo that TNC can promote damage repair in a rat model of TBI, through enhancing the proliferation of endogenous NSCs. We believe that these findings provide a mechanistic understanding of why neonates show better neuroregenerative abilities than adults. This also provides a potential future therapeutic target, TNC, for injury repair after TBI. Stem Cells 2019;37:1344-1356.

The Role of Smurf1 in Neuronal Necroptosis after Lipopolysaccharide-Induced Neuroinflammation.

The role of inflammation in neurological disorders such as Alzheimer's disease and Parkinson's disease is gradually recognized and leads to an urgent challenge. Smad ubiquitination regulatory factor 1 (Smurf1), one member of the HECT family, is up-regulated by proinflammatory cytokines and associated with apoptosis in acute spinal cord injury. However, the function of Smurf1 through promoting neuronal necroptosis is still limited in the central nervous system (CNS). Hence, we developed a neuroinflammatory model in adult rats following lipopolysaccharide (LPS) lateral ventral injection to elaborate whether Smurf1 is involved in necroptosis in CNS injury. The up-regulation of Smurf1 detected in the rat brain cortex was similar to the necroptotic marker RIP1 expression in a time-dependent manner after LPS-induced neuroinflammation. Meanwhile, Smurf1 knockdown with siRNA inhibited neuronal necroptosis following LPS-stimulated rat pheochromocytomal PC12 cells. Thus, it was indicated that LPS-induced necroptosis could be promoted by Smurf1. In short, these studies suggest that Smurf1 might promote neuronal necroptosis after LPS-induced neuroinflammation, which might act as a novel and potential molecular target for the treatment of neuroinflammation associated diseases.

Up-regulation of FOS-like antigen 1 contributes to neuronal apoptosis in the cortex of rat following traumatic brain injury.

Neuronal apoptosis is an important process of secondary brain injury which is induced by neurochemical signaling cascades after traumatic brain injury (TBI). Present study was designed to investigate whether FOS-like antigen 1 (Fra-1) is involved in the neuronal apoptosis. Western blot analysis and immunohistochemistry in a rat TBI model revealed a significant increase in the expression of Fra-1 in the ipsilateral brain cortex, which was in parallel with increase in the expression of active caspase-3. With immunofluorescence double-labeling, Fra-1 was colocalized with active caspase-3 and with NeuN, a neuronal marker. In an in vitro cell injury model, H2O2 exposure induced cell apoptosis and reduced cell viability and at the same time, a similar increased expression of active caspase-3, p53 and Fra-1 was found in PC12 cells. Down-regulation of Fra-1 through transfection with Fra-1 siRNA remarkably elevated cell viability, reduced the expression of active caspase-3 and p53, and decreased apoptosis of PC12 cells after H2O2 exposure. Taken together, present findings suggest that Fra-1 may be involved in the induction of neuronal apoptosis through up-regulating p53 signaling pathway and that this action may contribute to the secondary neuropathological process after TBI.

The O-GlcNAc Modification of CDK5 Involved in Neuronal Apoptosis Following In Vitro Intracerebral Hemorrhage.

Contrary to cell cycle-associated cyclin-dependent kinases, CDK5 is best known for its regulation of signaling processes in regulating mammalian CNS development. Studies of CDK5 have focused on its phosphorylation, although the diversity of CDK5 functions in the brain suggests additional forms of regulation. Here we expanded on the functional roles of CDK5 glycosylation in neurons. We showed that CDK5 was dynamically modified with O-GlcNAc in response to neuronal activity and that glycosylation represses CDK5-dependent apoptosis by impairing its association with p53 pathway. Blocking glycosylation of CDK5 alters cellular function and increases neuronal apoptosis in the cell model of the ICH. Our findings demonstrated a new role for O-glycosylation in neuronal apoptosis and provided a mechanistic understanding of how glycosylation contributes to critical neuronal functions. Moreover, we identified a previously unknown mechanism for the regulation of activity-dependent gene expression, neural development, and apoptosis.

Exposure of the Cavernous Sinus via the Endoscopic Transorbital and Endoscopic Endonasal Approaches: A Comparative Study.

OBJECTIVE: To compare the endoscopic transorbital approach (ETOA) and endoscopic endonasal approach (EEA) in terms of cavernous sinus (CS) exposure. METHODS: Four cadaveric heads (8 sides) were dissected. The CS was accessed using the EEA and ETOA. Stereotactic measurements of the length of the main structures exposed, angles of attack, depths of surgical corridor, and areas of exposure were obtained and compared between the approaches. An illustrative case is also presented. RESULTS: The endoscopic transorbital approach (ETOA) exposed the lateral and superior compartments of the CS without obstruction by the internal carotid artery (ICA). The EEA exposed all compartments after mobilizing the ICA. Both approaches enabled similar exposure of the cranial nerves. The depth of surgical corridor was significantly shorter with the ETOA (P < 0.01). The areas of lateral compartment exposure were similar. As the number of instruments placed into the surgical channel increased, the available angles of attack with the ETOA became smaller and were smaller than those of the EEA. In the clinical case presented, the tumor was successfully removed without complications. CONCLUSIONS: The ETOA has the advantages of a sterile surgical channel, short operation time, little patient trauma, short surgical corridor, large exposure area, and interdural pathway; moreover, it allows dissection through the interdural space without entering the neurovascular compartment of the CS. Although the space for manipulation of instruments is limited, the ETOA is suitable for treating selected tumors in the superior and lateral compartments of the CS.

Beta2 adrenergic receptor-mediated abnormal myelopoiesis drives neuroinflammation in aged patients with traumatic brain injury.

Aged patients often suffer poorer neurological recovery than younger patients after traumatic brain injury (TBI), but the mechanisms underlying this difference remain unclear. Here, we demonstrate abnormal myelopoiesis characterized by increased neutrophil and classical monocyte output but impaired nonclassical patrolling monocyte population in aged patients with TBI as well as in an aged murine TBI model. Retrograde and anterograde nerve tracing indicated that increased adrenergic input through the central amygdaloid nucleus-bone marrow axis drives abnormal myelopoiesis after TBI in a ß2-adrenergic receptor-dependent manner, which is notably enhanced in aged mice after injury. Selective blockade of ß2-adrenergic receptors rebalances abnormal myelopoiesis and improves the outcomes of aged mice after TBI. We therefore demonstrate that increased ß2-adrenergic input-driven abnormal myelopoiesis exacerbates post-TBI neuroinflammation in the aged, representing a mechanism underlying the poorer recovery of aged patients and that blockade of ß2-adrenergic receptor is a potential approach to promote neurological recovery after TBI.

Endoscopy during neurotomy of the nervus intermedius for nervus intermedius neuralgia: a case report.

Nervus intermedius neuralgia (NIN) is a rare craniofacial neuralgia with features of paroxysmal pain in the deep ear. Because of sensory nerves overlap in the ear, the diagnosis of NIN is often difficult and not definitive. Here, we present the case of a 70-year-old woman who had deep-ear pain for more than 4 years and was diagnosed with trigeminal neuralgia and treated with carbamazepine without relief in another hospital. Magnetic resonance tomographic angiography revealed no neurovascular conflict with the trigeminal nerve, whereas the anterior inferior cerebellar artery (AICA) was close to the VII/VIII complex. We performed left-sided suboccipital retrosigmoid craniotomy. Surgical exploration under endoscopy clearly showed that the nervus intermedius was compressed by the AICA from behind. The ear pain was completely relieved immediately after nervus intermedius sectioning. The intraoperative findings and postoperative results confirmed that the compression of the nervus intermedius by the AICA caused the otalgia. A patient's specific pain, combined with preoperative imaging examination, is useful in the diagnosis of NIN. Neuroendoscopy has the advantages of enabling a clear field of view and close observation, thus aiding in the identification and accurate cutting of the nervus intermedius during the operation.

Novel Insights into MSK1 Phosphorylation by MRKß in Intracerebral Hemorrhage-Induced Neuronal Apoptosis.

Neuronal apoptosis is regarded as one of the most important pathophysiological changes of intracerebral hemorrhagic (ICH) stroke-a major public health problem that leads to high mortality rates and functional dependency. Mitogen-and stress-activated kinase (MSK) 1 is implicated in various biological functions in different cell types, including proliferation, tumorigenesis and responses to stress. Our previous study showed that MSK1 phosphorylation (p-MSK1) is related to the regulation of LPS-induced astrocytic inflammation, and possibly acts as a negative regulator of inflammation. In this study, we identified a specific interaction between MSK1 and MRKß (MLK-related kinase)-a member of the MAPK pathway-during neuronal apoptosis. In an ICH rat model, western blotting and immunohistochemical analysis revealed that both MRKß and phosphorylation of MSK1 (p-MSK1 Ser376) were significantly upregulated in cells surrounding the hematoma. Triple-immunofluorescent labeling demonstrated the co-localization of MRKß and p-MSK1 in neurons, but not astrocytes. Furthermore, MRKß was partially transported into the nucleus, and interacted with p-MSK1 in hemin-treated neurons. Immunoprecipitation showed that MRKß and p-MSK1 exhibited an enhanced interaction during the pathophysiology process. Utilizing small interfering RNAs to knockdown MRKß or MSK1, we verified that MSK1 Ser376 is a phosphorylation site targeted by MRKß. We also observed that the phosphorylation of NF-κB p65 at Ser276 was mediated by the MRKß-p-MSK1 complex. Furthermore, it was found that the neuronal apoptosis marker, active caspase-3, was co-localized with MRKß and p-MSK1. In addition, flow cytometry analysis revealed that knockdown of MRKß or MSK1 specifically resulted in increased neuronal apoptosis, which suggested that the MRKß-p-MSK1 complex might exert a neuroprotective function against ICH-induced neuronal apoptosis. Taken together, our data suggest that MRKß translocated into the nucleus and phosphorylated MSK1 to protect neurons via phosphorylation of p65-a subunit of nuclear factor κB.

Neuroendoscopic Resection of Trigeminal Schwannoma in the Pterygopalatine/Infratemporal Fossa via the Transnasal Perpendicular Plate Palatine Bone or Transnasal Maxillary Sinus Approach.

BACKGROUND: Both the pterygopalatine fossa (PPF) and the infratemporal fossa (ITF) lie outside the midline of the skull base. Lesions in the PPF or ITF include trigeminal schwannoma (trigeminal schwannoma, TS), which originates from the second or third branch of the trigeminal nerve (maxillary nerve or mandibular nerve). Due to their typically deep anatomic location, lesions in the PPF or ITF can be difficult to treat using traditional surgical approaches. In recent years, because of their advantages, which include the fact that they allow the problem to be observed close up, neuroendoscopic techniques are increasingly being applied in skull base surgery, especially in treatment of lesions around the midline of the base of the skull. This study aims to 1) evaluate the neuroendoscopic treatment of lesions in PPF or ITF via the transnasal palate bone perpendicular plate or transnasal maxillary sinus approach and 2) analyze the clinical significance of this approach. METHODS: We retrospectively analyzed 3 cases of PPF TSs and 1 case of ITF TS treated between January 2015 and May 2017. All of the cases underwent neuroendoscopic resection of TSs located in the PPF via the nasal perpendicular plate palatine bone (or nasal maxillary sinus) approach. RESULTS: Two cases of PPF TSs were characterized by a thin palate bone perpendicular plate due to oppressed absorption of the tumor. Therefore the endoscopic transnasal palate bone perpendicular plate approach was employed. Additionally, 1 case of PPF TSs and 1 case of ITF TS were resected via the transnasal maxillary sinus approach. All 4 patients received total resection under endoscopy and recovered well after their respective operations without cerebrospinal fluid leakage, although 1 patient experienced postoperative dry eye symptoms and 1 other patient showed no improvement in facial numbness before and after the operation. CONCLUSIONS: Neuroendoscopic surgery performed via the transnasal perpendicular plate palatine bone or transnasal maxillary sinus approach has its own unique advantages in removing TSs in PPF and in ITF: Notably, the tumor can be exposed and dealt with under direct vision, which prevents damage to important structures, such as the internal carotid and maxillary nerves, while at the same time helping to achieve total removal of TSs. Furthermore, by adopting this approach versus traditional skull base surgery, postoperative trauma can be reduced significantly, which should be advocated for in this time of minimal invasive surgery.

Laparoscopic-Assisted Resection for Retroperitoneal Dumbbell-Shaped Lumbar Spinal Schwannomas: Operative Technique and Surgical Results.

BACKGROUND: Retroperitoneal dumbbell lumbar spinal schwannomas (RDLSSs) classified as the Eden type 4 are composed of small intervertebral foramen components and large paravertebral components extending into the retroperitoneal cavity. The surgical management of RDLSSs s remains a great challenge for all neurosurgeons because of the features of tumor. OBJECTIVE: To present our experience in the laparoscopic resection of RDLSSs and to evaluate endoscopy surgery by an anterior approach for the treatment of RDLSSs. METHODS: We performed a retrospective review of 3 patients with RDLSSs who underwent laparoscopic surgery by an anterior approach between June 2013 and July 2014. Patient demographics, operative reports, and pre- and postoperative images were reviewed. RESULTS: All tumors were removed completely with retroperitoneal laparoscopy by the anterior approach. There were no major morbidities related to the surgical procedure in this series, and all patients recovered from surgery. The preoperative symptoms either improved or resolved in 2 patients, whereas they remained unchanged in 1 patient. Postoperative follow-up ranged from 12 to 24 months, and none of the patients showed signs of tumor recurrence or spinal deformity. CONCLUSIONS: The operative plan should be tailored to the features of the RDLSS. Retroperitoneal laparoscopy surgery by the anterior approach can produce safe and effective resection of RDLSSs with minimal postoperative complications. This procedure may be preferred for RDLSSs mainly located in the retroperitoneum without spinal canal extension.

The Expression of NP847 and Sox2 after TBI and Its Influence on NSCs.

The proliferation and differentiation of neural stem cells (NSCs) is important for neural regeneration after cerebral injury. Here, for the first time, we show that phosphorylated (p)-ser847-nNOS (NP847), rather than nNOS, may play a major role in NSC proliferation after traumatic brain injury (TBI). Western blot results demonstrated that the expression of NP847 and Sox2 in the hippocampus is up-regulated after TBI, and they both peak 3 days after brain injury. In addition, an immunofluorescence experiment indicated that NP847 and Sox2 partly co-localize in the nuclei of NSCs after TBI. Further immunoprecipitation experiments found that NP847 and Sox2 can directly interact with each other in NSCs. Moreover, in an OGD model of NSCs, NP847 expression is decreased, which is followed by the down-regulation of Sox2. Interestingly, in this study, we did not observe changes in the expression of nNOS in the OGD model. Further research data suggest that the NP847-Sox2 complex may play a major role in NSCs through the Shh/Gli signaling pathway in a CaMKII-dependent manner after brain injury.

Phosphorylation of mitogen- and stress-activated protein kinase-1 in astrocytic inflammation: a possible role in inhibiting production of inflammatory cytokines.

PURPOSE: It is generally accepted that inflammation has a role in the progression of many central nervous system (CNS) diseases, although the mechanisms through which this occurs remain unclear. Among mitogen-activated protein kinase (MAPK) targets, mitogen- and stress-activated protein kinase (MSK1) has been thought to be involved in the pathology of inflammatory gene expression. In this study, the roles of MSK1 activation in neuroinflammation were investigated. METHODS: The bacterial lipopolysaccharide (LPS)-induced brain injury model was performed on Sprague-Dawley rats. The dynamic expression changes and the cellular location of p-MSK1 in the brain cortex were detected by Western blot and immunofluorescence staining. The synthesis of inflammatory cytokines in astrocytes was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Phosphorylated MSK1 (p-MSK1 Thr-581) was induced significantly after intracerebral injection of LPS into the lateral ventricles of the rat brain. Specific upregulation of p-MSK1 in astrocytes was also observed in inflamed cerebral cortex. At 1 day after LPS stimulation, iNOS, TNFα expression, and the astrocyte marker glial fibrillary acidic protein (GFAP) were increased significantly. Also, in vitro studies indicated that the upregulation of p-MSK1 (Thr-581) may be involved in the subsequent astrocyte inflammatory process, following LPS challenge. Using an enzyme-linked immunosorbent assay (ELISA), it was confirmed that treatment with LPS in primary astrocytes stimulated the synthesis of inflammatory cytokines, through MAPKs signaling pathways. In cultured primary astrocytes, both knock-down of total MSK1 by small interfering RNAs (siRNA) or specific mutation of Thr-581 resulted in higher production of certain cytokines, such as TNFα and IL-6. CONCLUSIONS: Collectively, these results suggest that MSK1 phosphorylation is associated with the regulation of LPS-induced brain injury and possibly acts as a negative regulator of inflammation.

The expression patterns of Septin-9 after traumatic brain injury in rat brain.

Septins are a novel group of GTPases, which are first identified in yeast and more recently found in a wide range of animal cells. Septin-9, a novel septin family member, is expressed ubiquitously and involved in an increasing number of signaling cascades. However, information regarding its distribution and possible function in the central nervous system (CNS) is limited. In this study, western blot analysis and immunohistochemistry showed a significant upregulation of Septin-9 in the ipsilateral peritrauma cortex compared with the sham group. Immunofluorescent labeling indicated that Septin-9 was localized strikingly in the cytoplasm of neurons, but not astrocytes and oligodendrocytes. The co-localization of Septin-9 and active caspase-3 was also examined in the ipsilateral cortex. In addition, the expression patterns of active caspase-3 were parallel with that of Septin-9. Quantitative real-time RT-PCR also was used to detect Seption-9 mRNA level. Based on our data, we speculated that traumatic brain injury may be a stimulus to induce the Septin-9 expression, and Septin-9 might play an important role in the pathophysiology process in the CNS after traumatic brain injury. Taken together, this is the first description of Septin-9 expression changes during the central nervous system lesion and repair, but further studies are needed to understand the cell signaling pathway which can direct the exact role of Septin-9 following traumatic brain injury.

OCT4 is epigenetically regulated by DNA hypomethylation of promoter and exon in primary gliomas.

Glioma is the leading cause of tumor-related mortality in the central nervous system. There is increasing evidence that the self-renewal capacity of cancer cells is critical for the initiation, growth and recurrence of tumors. OCT4 is a transcription factor that plays a key role in regulating the self-renewal ability of embryonic stem cells. DNA methylation is involved in the regulation of OCT4 expression during the development and differentiation of embryonic stem cells and neural stem cells. In the present study, we reported that OCT4 was highly expressed in primary gliomas and its expression levels increased in parallel with pathological grades. BSP analysis showed that the methylation levels of OCT4 gene promoter and exon were significantly reduced in comparison with the normal group and were negatively correlated with OCT4 gene expression in primary gliomas. In vitro, OCT4 gene expression was upregulated following treatment by a demethylation reagent in glioma cell lines. Our findings suggest that OCT4 is epigenetically regulated by DNA hypomethylation in primary gliomas, which may provide evidence for the role of DNA methylation in tumor and may present a new direction for developing more powerful strategies to treat glioma in the clinic.

SCY1-like 1 binding protein 1 (SCYL1-bp1) interacts with p53-induced RING H2 protein (Pirh2) after traumatic brain injury in rats.

Traumatic brain injury (TBI) triggers a complex series of neurochemical and signaling changes that lead to neuronal dysfunction and overreactive astrocytes. In the current study, we showed that interactions between SCYL1-bp1 and Pirh2 are involved in central nervous system (CNS) injury and repair. Western blot and immunohistochemical analysis of an acute traumatic brain injury model in adult rats revealed significantly increased levels of SCYL1-bp1 and Pirh2 in the ipsilateral brain cortex, compared to contralateral cerebral cortex. Immunofluorescence double-labeling analyses further revealed that SCYL1-bp1 is mainly co-expressed with NeuN. Terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling staining data supported the involvement of SCYL1-bp1 and Pirh2 in neuronal apoptosis after brain injury. We additionally examined the expression profiles of active caspase-3, which were altered in correlation with the levels of SCYL1-bp1 and Pirh2. Notably, both SCYL1-bp1 and Pirh2 were colocalized with active caspase-3, and all three proteins participated in neuronal apoptosis. Immunoprecipitation experiments further revealed interactions of these proteins with each other in the pathophysiology process. To our knowledge, this is the first study to report interactions between SCYL1-bp1 and Pirh2 in traumatic brain. Our data collectively indicate that SCYL1-bp1 and Pirh2 play important roles in CNS pathophysiology after TBI.

Clinical significance and prognostic value of PAX3 expression in human glioma.

The paired box 3 (PAX3), a crucial transcription factor, is normally expressed during embryonic development and is absent in normal adult human tissues. Deregulated expression of PAX3 has been observed in tumors like rhabdomyosarcoma and melanomas. To assess deregulated PAX3 expression in patients with gliomas, these samples from 57 glioma patients (13 grade I, 16 grade II, 14 grade III, and 14 grade IV tumors) and 10 normal brain specimens acquired from 10 patients undergoing surgery for epilepsy as control were obtained. PAX3 expression was measured by RT-PCR, Western blot, and immunohistochemistry. Survival analyses were performed using the Kaplan-Meier method. Association between PAX3 expression, clinicopathological characteristics, and patients' survival were analyzed by using SPSS 17.0. We found that the expression of PAX3 was upregulated in high-grade glioma tissues compared with that in low-grade and normal brain tissues, and increased with ascending tumor World Health Organization (WHO) grades (P = 0.001). The increased PAX3 expression in gliomas was significantly associated with higher WHO grade (P = 0.021) and poorer disease-specific survival of patients (P = 0.001). Our results suggested that PAX3 might be an intrinsic regulator of progression in glioma cells and it might serve as a prognostic factor for this dismal disease.

BDNF blended chitosan scaffolds for human umbilical cord MSC transplants in traumatic brain injury therapy.

This study tested the cytotoxicity of a BDNF blended chitosan scaffold with human umbilical cord mesenchymal stem cells (hUC-MSCs), and the in vitro effect of BDNF blended chitosan scaffolds on neural stem cell differentiation with the aim of contributing alternative methods in tissue engineering for the treatment of traumatic brain injury (TBI). The chitosan scaffold based on immobilization of BDNF by genipin (GP) as a crosslinking agent referred to hereafter as a CGB scaffold was prepared by freezing-drying technique. hUC-MSCs were co-cultured with the CGB scaffold. Fluorescent nuclear staining (Hoechst 33342) was employed to determine the attachment of the hUC-MSCs to CGB scaffolds on the 1st, 3rd, 7th and 10th day of co-culture. The viability of hUC-MSCs adhered to the CGB scaffold was determined by digesting with 0.25% trypsin and evaluating with the cell counting kit-8 (CCK-8). Prior to this, the diameter and porosity of CGB scaffolds were measured. The amount of BDNF released from CGB over a 30 day period was determined by ELISA. Finally, we investigated whether the released BDNF can induce NSC to differentiate into neurons. There were no significant differences in diameter and porosity of individual CGB scaffolds (P > 0.05). There were on average more cells on the CGB scaffold on the first day than on any other day sampled (P < 0.05). The CGB scaffolds released BDNF in a uniform profile, whereas the CB scaffolds only released BDNF during the first 3 days. BDNF released from CGB scaffold promoted neuronal differentiation of NSCs and led to significant differences in differentiation rate and average neuron perimeter compared with the control group. The results of this study demonstrate that CGB scaffolds are biocompatible with hUC-MSCs and that granular CGB scaffolds covered with hUC-MSCs are expected to generate new advances for future treatment of traumatic brain injury.