a-comprehensive-procedure-to-evaluate-vitro-performance-putative

A Comprehensive Procedure to Evaluate the <em>In Vitro</em> Performance of the Putative Hemangioblastoma Neovascularization Using the Spheroid Sprouting Assay

The inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene plays a crucial role in the development of hemangioblastomas (HBs) within the human ...

Fudan University

This study aimed at an analysis of expression of epidermal-type and brain-type fatty acid-binding proteins (E-FABP and B-FABP, also called FABP5 and FABP7, respectively) in adult hippocampus and their potential value as neuroprotective factors after ischemic brain damage in monkey model. The immunostaining and Western blotting results show that FABP5 was mainly expressed in neurons, whereas FABP7 was primarily expressed in astrocytes and progenitors of the subgranular zone (SGZ). Interestingly, FABP5 expression in neurons increased in cornu Ammonis 1 (CA1) and remains stable within dentate gyrus (DG) after ischemia; FABP7 expression increased within both CA1 and SGZ. This indicates a potential role for FABP5 and FABP7 in intracellular fatty acid transport within different neural cells. The change in FABP5-7 expression within CA1 and DG of the adult postischemic hippocampus was compatible with previous findings of downregulation in CA1 neurons and upregulation in SGZ progenitor cells after ischemia. Altogether, the present data suggest that polyunsaturated fatty acids, such as docosahexaenoic acid, may act via FABP5 or 7 to regulate adult postischemic hippocampal neuronal antiapoptosis or neurogenesis in primates.

Cellular localization of epidermal-type and brain-type fatty acid-binding proteins in adult hippocampus and their response to cerebral ischemia.

G-protein coupled receptor 40 (GPR40), which is expressed ubiquitously in the human brain and pancreas, is a member of the large family of seven-transmembrane receptors and can be activated by polyunsaturated fatty acid (PUFA), in particular docosahexaenoic acid (DHA). Recent studies have shown that the DHA/GPR40 signaling pathway may be closely related with adult neurogenesis in the hippocampus. Here, reconstructing pEGFP-N1 vector-expressing GPR40 gene in cultured rat neural stem cells, we demonstrated that DHA-induced neuronal differentiation, neurite growth and branching of adult rat stem cells is mediated at least in part through GPR40 and it remains effective even at low concentrations of DHA. Furthermore, we also revealed that DHA/GPR40 induced the PLC/IP3 signaling pathway and therefore modulated intracellular Ca(2+) mobilization independent of extracellular Ca(2+) concentration. This may be involved in neuronal differentiation and neurite growth in rat neural stem cells transfected with GPR40 gene. These data provide a new sight in the future utilization of neural stem cells transplantation.

DHA promotes the neuronal differentiation of rat neural stem cells transfected with GPR40 gene.

The cytological origin of central nervous system hemangioblastoma (HB) remains unclear and controversial, largely owing to a lack of in-depth characterization of tumorigenic cells and their progeny tracking. We have now detected a cell subpopulation by stage-specific embryonic antigen-1 expression, which were defined as tumor-initiating cells (TICs) in both sporadic and familial HBs. These TICs subpopulations had universal neural stem cell characteristics. Nevertheless, the freshly sorted TICs endowed with potential of multi-progeny derivatives, including HB components and non-HB ingredients, depended on environmental induction in vitro. Importantly, the freshly harvested TICs formed malignant tumors by injection into conventional mice model, while did redevelop the characteristic HB-like structures within a special mice model with HB-microenvironment, indicating HB niche dependency for the TICs derivative specification. Taken together, the data of the present study suggested that HBs might derive from neoplastic transformation of neural stem cells/progenitors in the specific niche.

Hemangioblastomas might derive from neoplastic transformation of neural stem cells/progenitors in the specific niche.

The cytological origin of hemangioblastomas (HBs) is controversial possibly owing to limitation in the framework of normal vascular development. Our previous study reported that SSEA1 (stage-specific embryonic antigen-1) cells had the potential of HB-like structure formation in vitro cellular models. Here, we characterized primary proliferating tumor-initiating cells (TICs) and their neoplasmtic transformation. Neural stem cell marker SSEA1 and its lineage-related genes were demonstrated; no embryonic and mesenchymal stem cell markers were detected whereas their lineage-related genes in part were activated. Immunohistochemistry showed that the proliferating marker was preferentially expressed in SSEA1 cells. There was significant difference in the percentage of SSEA1 cells (SSEA1+/Ki67+ cells) between inherited and sporadic HBs although the tumor proliferative index (Ki67+ cells/ all cells) did not reach statistical significance between the two groups. Further, corresponding to the morphological changes of nucleolus in number and size, these highly proliferating SSEA1 cells demonstrated coexpression of either D2-40 or the mesodermal marker Scl (stem cell leukemia), brachyury, and Flk-1 (vascular endothelial growth factor-2), respectively, indicative of the neoplasmtic transformation into the stromal or vascular cells. The present data suggest that HBs might derive from neoplastic transformation of neural stem cells/progenitors. Such findings also provide new insights into the biology of HBs and the definition of TICs in situ, as well as the mechanisms of tumor neovascularization.

Identification of tumorigenic cells and implication of their aberrant differentiation in human hemangioblastomas.

Brainstem hemangioblastomas (HBs) are considered one of the most challenging lesions in surgical procedures. We present our institutional experience with 116 patients over a period of 20 years in the treatment of HBs.

Neurosurgical Management of Brainstem Hemangioblastomas: A Single-Institution Experience with 116 Patients.

Genetic imprinting suggested by maternal DNA methylation in CNS hemangioblastoma with clinical phenotypes of VHL disease.

The initiation and formation of haemangioblastoma (HB) neovascularisation remain unknown, with concomitant controversy on its cytological origin. We detected HB-derived specific haematopoietic progenitors identified by surface expression of CD41 and CD45, which are similar to human embryonic vasculogenesis. CD41/CD45 cells expressed mesodermal markers, including SCL, Flk1 and c-kit. CD41 also seemed to appear before CD45 on haematopoietic progenitors. In vitro analysis showed that the CD41(+)/CD45 subpopulation gave rise to occasional primitive erythroid activity and endothelial marker expression. Meanwhile, kinetic investigation of the CD41(+)/CD45(+) subpopulation showed that some molecules, including SCL, Flk1 and c-kit, were involved in vascular formation. The CD45(+)/c-kit(+) population that lacked primitive haematopoiesis came from CD41(+) cells. Acquisition of CD45 expression by the haematopoietic progenitors was associated with advanced differentiation towards the vascular cell lineage. Taken together, the present data suggested that CD41 and CD45 expression marked the onset of HB neovascularisation and the stepwise development of the angioformative period. Our findings provide new insights into the mechanisms of HB neovascularisation and the underlying therapeutic targets of anti-vascular treatment.

CD41 and CD45 expression marks the angioformative initiation of neovascularisation in human haemangioblastoma.

Traumatic brain injury (TBI) is a leading cause of death and disability. Previous studies have investigated the association of apolipoprotein E (APOE) ε4 with functional outcome after TBI and reported inconsistent results.The purpose of this study was to perform a systematic literature search and conduct meta-analyses to examine whether APOE ε4 is associated with poorer functional outcome in patients with TBI.We performed a systematic literature search in PubMed, Cochrane Library, Embase, Google Scholar, and HuGE.The eligibility criteria of this study included the following: Patients had TBI; the studies reported APOE genotype data or provided odds ratios (ORs) and the corresponding 95% confidence intervals (CIs); the functional outcome was assessed using the Glasgow Outcome Scale (GOS) or the Glasgow Outcome Scale Extended (GOSE); and patients were followed for at least 3 months after TBI.In all meta-analyses, we used random-effects models to calculate the odds ratio as a measure of association. We examined the association of APOE ε4 with functional outcome at different time points after TBI.A total of 12 studies met the eligibility criteria and were included in the meta-analyses. We did not find a significant association between APOE ε4 and functional outcome at 6 (P = 0.23), 12 (P = 0.44), and 24 months (P = 0.85) after TBI. However, APOE ε4 was associated with an increased risk of unfavorable long-term (≥6 months) functional outcome after TBI (OR = 1.36, 95% CI: 1.07-1.74, P = 0.01).Limitations of this study include The sample size was limited; the initial severity of TBI varied within and across studies; we could not control for potential confounding factors, such as age at injury and sex; a meta-analysis of the genotype dosage effect was not feasible; and we could not examine the association with specific factors such as neurobehavioral or specific cognitive functions.Our meta-analysis indicates APOE ε4 is associated with the long-term functional outcome of patients with TBI. Future studies that control for confounding factors, with large sample sizes and more homogeneous initial TBI severity levels, are needed to validate the findings from this study.

The Association Between Apolipoprotein E and Functional Outcome After Traumatic Brain Injury: A Meta-Analysis.

Posttraumatic stress disorder (PTSD) is a complex mental disorder and can severely interfere with the normal life of the affected people. Previous studies have examined the association of PTSD with genetic variants in multiple dopaminergic genes with inconsistent results. To perform a systematic literature search and conduct meta-analysis to examine whether genetic variants in the dopaminergic system is associated with PTSD. Data Sources: PubMed, Cochrane Library, Embase, Google Scholar, and HuGE. Study eligibility criteria and participants: The studies included subjects who had been screened for the presence of PTSD; the studies provided data for genetic variants of genes involved in the dopaminergic system; the outcomes of interest included diagnosis status of PTSD; and the studies were case-control studies. Study appraisal and synthesis methods: Odds ratio was used as a measure of association. We used random-effects model in all the meta-analyses. Between-study heterogeneity was assessed using I², and publication bias was evaluated using Egger test. Findings from meta-analyses were confirmed using random-effects meta-analyses under the framework of generalized linear model (GLM). A total of 19 studies met the eligibility criteria and were included in our analyses. We found that rs1800497 in DRD2 was significantly associated with PTSD (OR = 1.96, 95% CI: 1.15-3.33; P = 0.014). The 3'-UTR variable number tandem repeat (VNTR) in SLC6A3 also showed significant association with PTSD (OR = 1.62, 95% CI: 1.12-2.35; P = 0.010), but there was no association of rs4680 in COMT with PTSD (P = 0.595). Sample size is limited for some studies; type and severity of traumatic events varied across studies; we could not control for potential confounding factors, such as age at traumatic events and gender; and we could not examine gene-environment interaction due to lack of data. We found that rs1800497 in DRD2 and the VNTR in SLC6A3 showed significant association with PTSD. Future studies controlling for confounding factors, with large sample sizes and more homogeneous traumatic exposure, are needed to validate the findings from this study.

The Association Between Genetic Variants in the Dopaminergic System and Posttraumatic Stress Disorder: A Meta-Analysis.

Multiple sclerosis (MS) is the most frequent nontraumatic disabling neurological disease among young adults. Previous studies have examined the association of rs703842 in CYP27B1 with MS susceptibility, with inconsistent results reported.The objective of this study is to conduct a systematic literature search and perform meta-analyses to examine whether rs703842 is associated with MS risk.We searched potential literature in PubMed, Cochrane Library, Embase, Google Scholar, Web of Science, and HuGE by using the following inclusion criteria: studies were on human subjects; the studies were case-control studies; studies included subjects who had MS and those who did not have MS; and the studies provided genotype data for rs703842 for subjects who had and did not have MS, or provided odds ratios (ORs) and the 95% confidence intervals (CIs) for assessing the association of rs703842 with MS, or provided sufficient data for the calculation of OR and the 95% CI. We used random-effects models to calculate the OR as a measure of association. We used I to assess between-study heterogeneity, and a funnel plot and Egger test to assess publication bias.Seven studies published since 2008 met the eligibility criteria and were included in the meta-analyses. We found that the C allele was significantly associated with reduced MS susceptibility (OR = 0.88, 95% CI: 0.80-0.89; P < 0.0001). We also found significant association of rs703842 with MS risk using a dominant and a recessive model (both P < 0.0002). Our results remain unchanged if our meta-analysis was limited to studies that included only Caucasian participants (OR = 0.85, 95% CI: 0.80-0.90; P < 0.0001).Our study has several limitations: The sample size is limited; We were unable to control for some important confounding factors as data for individual participant were not available; and Most of the included studies focus on MS risk in Caucasian. As a result, we could not perform meta-analysis for assessing the relationship in other ethnic groups.In summary, we found that the genetic variant rs703842 in CYP27B1 is associated with MS risk in Caucasians. More studies with larger sample size that control for important confounding factors are needed to validate the findings from this study.

The Association Between Genetic Polymorphism rs703842 in CYP27B1 and Multiple Sclerosis: A Meta-Analysis.

The von Hippel-Lindau (VHL) tumor suppressor gene plays a prominent role in the development of hemangioblastomas (HBs) within specific regions of the human' central nervous system (CNS). Alterations in VHL gene are rarely observed in the more common features of human VHL-related tumors in animal models, and VHL heterozygous knockout (VHL+/-) mice do not develop HBs. We tested whether VHL heterozygous knockout mice exhibited genetic predisposition to the development of HBs and conferred a selective advantage involving growth of blood vessels to its carrier. No differences were observed between wild-type and VHL+/- mice in development ad reproduction. The heterozygous VHL+/- mice did not develop higher genetic susceptibility to CNS-HBs over their lifetime. Furthermore, this recessive VHL gene heterozygosity is relatively stable. Interestingly, we found these heterozygous VHL+/- mice gained an advantage conferring to angiogenic ability in a particular environment, compared with wild-type mice. The heterozygous VHL+/- mice obviously enhanced hypoxia inducible factor-1 (HIF)-dependent and Twist1 angiogenic mechanism in response to acute cerebral ischemia, resulting in decreased cerebral tissue damage and neuroprotective response through neovascularization. Our findings provide evidence of partial loss function of VHL as a novel precise therapeutic target in acute cerebral ischemia.

Neuroprotective effects respond to cerebral ischemia without susceptibility to HB-tumorigenesis in VHL heterozygous knockout mice.

Inactivation of the VHL tumour suppressor gene is a highly frequent genetic event in the carcinogenesis of central nervous system-(CNS) hemangioblastomas (HBs). The patterning of the similar embryonic vasculogenesis is an increasing concern in HB-neovascularization, and the classic vascular endothelial growth factor (VEGF)-mediated angiogenesis driven by VHL loss-of-function from human endothelium have been questioned. With this regard, we identify a distinct, VHL silencing-driven mechanism in which human vascular endothelial cells by means of increasing cell proliferation and decreasing cell apoptosis, is concomitant with facilitating accumulation of Twist1 protein in vascular endothelial cells in vitro. Importantly, this molecular mechanism is also pinpointed in CNS-HBs, and associated with the process of HB-neovascularization. In contrast with recent studies of HB-neovascularization, these modified cells did not endow with the typical features of vasculogenesis, indicating that this is a common angiogenesis implementing the formation of the vascular network. Taken together, these findings suggest that vasculogenesis and angiogenesis may constitute complementary mechanisms for HB-neovascularization, and could provide a rational recognition of single anti-angiogenic intervention including targeting to the Twist1 signalling for HBs.

Endothelial cells by inactivation of VHL gene direct angiogenesis, not vasculogenesis via Twist1 accumulation associated with hemangioblastoma neovascularization.

Hemangioblastomas (HBs) are uncommon tumors characterized by the presence of inactivating alterations in the von Hippel-Lindau (VHL) gene in inherited cases and by infrequent somatic mutation in sporadic entities. We performed whole exome sequencing on 11 HB patients to further elucidate the genetics of HBs. A total of 270 somatic variations in 219 genes, of which there were 86 mutations in 67 genes, were found in sporadic HBs, and 184 mutations were found in 154 genes in familial HBs. C: G>T: A and T: A>C: G mutations are relatively common in most HB patients. Genes harboring the most significant mutations include PCDH9, KLHL12, DCAF4L1, and VHL in sporadic HBs, and ZNF814, DLG2, RIMS1, PNN, and MUC7 in familial HBs. The frequency of CNV varied considerably within sporadic HBs but was relatively similar within familial HBs. Five genes, including OTOGL, PLCB4, SCEL, THSD4, and WWOX, have CNVs in the six patients with sporadic HBs, and three genes, including ABCA6, CWC27, and LAMA2, have CNVs in the five patients with familial HBs. We found new genetic mutations and CNVs that might be involved in HBs; these findings highlight the complexity of the tumorigenesis of HBs and pinpoint potential therapeutic targets for the treatment of HBs.

Article	Year
Cellular localization of epidermal-type and brain-type fatty acid-binding proteins in adult hippocampus and their response to cerebral ischemia. Hippocampus\| PubMed ID: 19623607	2010
DHA promotes the neuronal differentiation of rat neural stem cells transfected with GPR40 gene. Brain research\| PubMed ID: 20211608	2010
Hemangioblastomas might derive from neoplastic transformation of neural stem cells/progenitors in the specific niche. Carcinogenesis\| PubMed ID: 20974685	2011
Identification of tumorigenic cells and implication of their aberrant differentiation in human hemangioblastomas. Cancer biology & therapy\| PubMed ID: 21811099	2011
Neurosurgical Management of Brainstem Hemangioblastomas: A Single-Institution Experience with 116 Patients. World neurosurgery\| PubMed ID: 26026629	2015
Genetic imprinting suggested by maternal DNA methylation in CNS hemangioblastoma with clinical phenotypes of VHL disease. Journal of neuro-oncology\| PubMed ID: 26093619	2015
CD41 and CD45 expression marks the angioformative initiation of neovascularisation in human haemangioblastoma. Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine\| PubMed ID: 26468019	2016
The Association Between Apolipoprotein E and Functional Outcome After Traumatic Brain Injury: A Meta-Analysis. Medicine\| PubMed ID: 26579811	2015
The Association Between Genetic Variants in the Dopaminergic System and Posttraumatic Stress Disorder: A Meta-Analysis. Medicine\| PubMed ID: 26986136	2016
The Association Between Genetic Polymorphism rs703842 in CYP27B1 and Multiple Sclerosis: A Meta-Analysis. Medicine\| PubMed ID: 27175669	2016
Neuroprotective effects respond to cerebral ischemia without susceptibility to HB-tumorigenesis in VHL heterozygous knockout mice. Molecular carcinogenesis\| PubMed ID: 28574654	2017
Endothelial cells by inactivation of VHL gene direct angiogenesis, not vasculogenesis via Twist1 accumulation associated with hemangioblastoma neovascularization. Scientific reports\| PubMed ID: 28710479	2017
Whole exome sequencing identified genetic variations in Chinese hemangioblastoma patients. American journal of medical genetics. Part A\| PubMed ID: 28742274	2017
In Reply to the Letter to the Editor "Circumventricular Organ Origin of Hemangioblastoama; Hypothesis for Pathogenesis of Disease". World neurosurgery\| PubMed ID: 29179427	2017

DeXuan Ma

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