Cellular Distribution of C-C Motif Chemokine Ligand 2 Like Immunoreactivities in Frontal Cortex and Corpus Callosum of Normal and Lipopolysaccharide Treated Animal

Background: C-C motif chemokine ligand 2 (CCL2) is reported to be involved in the pathogenesis of various neurological and/or psychiatric diseases. Tissue or cellular expression of CCL2, in normal or pathological condition, may play an essential role in recruiting of monocytes or macrophages into the targeted organs, and be involved in a certain pathogenic mechanism. However, only a few studies focused on tissue and cellular distribution of the CCL2 peptide in the brain’s grey and white matters (GM, WM), and the changes of the GM and WM cellular CCL2 level in septic or endotoxic encephalopathy was not explored. Hence, the CCL2 cellular distribution in the front brain cortex and the corpus callosum (CC) WM was investigated in the present work by using immunofluorescent staining. Results: 1) Normally, CCL2 like immunoreactivity (CCL2-ir) in the CC is significantly higher than the cortex, especially when the measurement includes ependymal layer attached to the CC. 2) Structures surrounding the vasculatures contribute major CCL2-ir positive profiles in both GM and WM, but significantly more in the CC WM, in which they are bilaterally distributed and predominantly located in the lateral CC between the cingulate cortex and the lateral ventricles. 3) Following systemic lipopolysaccharide (LPS), the number of neuron-like CCL2-ir positive cells are increased significantly in the cortex, but not in the CC. 4) More CCL2-ir positive elements are accumulated inside microvasculature like structures in the CC WM, compared to those found in the cortex following systemic LPS. 5) Few macrophage/microglia marker-Iba-1 labeled structures exhibit CCL2-ir in normal cortex and CC, but the co-localization is significantly increased following systemic LPS. 6) Following saline or LPS injection, CCL2-ir and GFAP or Iba-1 double labeled structures are observed within the ependymal layer between the lateral ventricles and the CC. No accumulation of neutrophils was detected.Conclusion: there exist differences in the cellular distribution of the CCL2 peptide in the front brain cortex GM and the subcortical WM - the CC, in both the physiological condition and experimental endotoxemia. Which might cause different pathological change in the GM and WM.

Supratotal Resection of Periventricular Glioblastomas and Pathomorphological Rationale for Extensive Removal of Subventricular Zone

The aim of the research was to reveal the pathomorphological patterns of periventricular glioblastoma (PVG) dissemination and assess the rationale for extended surgical removal of subventricular zone (SVZ) as a step towards supratotal resection.A total of 54 patients (16 females and 38 males, mean age 48.9 ± 13.4 years, range 22–69) with PVG were prospectively included in the study. Standard preoperative evaluation included an MRI using 3D T1 with Gd-enhancement, T2, and T2-FLAIR series. The neuronavigation system was used to identify the SVZ and to remove of ventricular wall, additionally to image-guided total tumor resection. The pathomorphological assessment of PVG features with the description of the SVZ and changes in perifocal brain matter was performed by two pathologists.The median Karnofsky Performance Scale (KPS) score raised from 67.8 to 81.9 in the postoperative period. The overall median survival was 13.0 ± 2.7 months. The low postoperative KPS score (p = 0.05) and basal ganglia invasion (p = 0.008) significantly decreased survival rates.Microscopically, the typical multilayer structure of SVZ was disrupted. The invasive spread of tumor cells in thesubventricular space was identified. The ependymal layer had prominent dystrophic alterations of cells and destruction of intracellular connections. The hyperplastic reaction on neoplastic process was typical for adjacent ependyma.The pathomorphological identification of periventricular glioblastoma invasion in the subependymal space supports the supratotal tumor resection with removal of adjacent SVZ as a potential source for relapse.

RBP-J Deficiency Promoted The Proliferation and Differentiation of CD133-Positive Ependymal Cells In Vitro and In Vivo Studies

Although the ependymal cells were reported to have the characteristics of neural stem cells (NSCs), the properties of CD133-ependymal cells have not been uncovered, in particular, it is largely unknown about the effect of Notch signaling pathway on the neurogenesis of CD133-positive ependymal cells. By using the transgenic mouse and primarily cultured ependymal cells, we found that the immunoreactivity for prominin-1/CD133 was exclusively localized in the subventricular zone (SVZ) and ependymal layer of ventricles, moreover, most CD133-positive ependymal cells were co-labeled with Nestin. In addition, RBP-J, a key nuclear effector of Notch signaling pathway, was highly active in CD133-positive ependymal cells. Our results demonstrated that CD133-positive ependymal cells can differentiate into the immature and mature neurons, in particular, the number of CD133-positive ependymal cells differentiating into the immature and mature neurons was significantly increased following the deficiency or interference of RBP-J in vivo or in vitro. By using real-time qPCR and Western blot, we found that RBP-J and Hes1 were down-regulated while Notch1 was up-regulated in the expression levels of mRNAs and proteins following the deficiency or interference of RBP-J in vivo or in vitro. These results demonstrated RBP-J deficiency promoted the proliferation and differentiation of CD133-positive ependymal cells. Therefore, we speculated that RBP-J could maintain CD133-positive ependymal cells in the characteristics of NSCs possibly by regulating Notch1/RBP-J/Hes1 pathway.

Interstitial and cerebrospinal fluid exchanging process revealed by phase alternate labeling with null recovery MRI

Purpose: To develop Phase Alternate LAbeling with Null recovery (PALAN) MRI methods for the quantification of interstitial to cerebrospinal fluid flow (ICF) and cerebrospinal to interstitial fluid flow (CIF) in the brain. Method: In both T1-PALAN and apparent diffusion coefficient (ADC)-PALAN MRI methods, the cerebrospinal fluid (CSF) signal was nulled, while the residual interstitial fluid (ISF) was labeled by alternating the phase of pulses. ICF was extracted from the difference between the recovery curves of CSF with and without labeling. Similarly, CIF was measured by the T2-PALAN MRI method by labeling CSF, which took advance of the significant T2 difference between CSF and parenchyma. Results: Both T1-PALAN and ADC-PALAN observed a rapid occurrence of ICF at 67±56 ms and 13±2 ms interstitial fluid transit times, respectively. ICF signal peaked at 1.5 s for both methods. ICF was 1153±270 ml/100ml/min with T1-PALAN in the third and lateral ventricles, which was higher than 891±60 ml/100ml/min obtained by ADC-PALAN. The results of the T2-PALAN suggested the ISF exchanging from ependymal layer to the parenchyma was extremely slow. Conclusion: The PALAN methods are suitable tools to study ISF and CSF flow kinetics in the brain.

Kidins220 deficiency causes ventriculomegaly via SNX27-retromer-dependent AQP4 degradation

Several psychiatric, neurologic and neurodegenerative disorders present increased brain ventricles volume, being hydrocephalus the disease with the major manifestation of ventriculomegaly caused by the accumulation of high amounts of cerebrospinal fluid (CSF). The molecules and pathomechanisms underlying cerebral ventricular enlargement are widely unknown. Kinase D interacting substrate of 220 kDa (KIDINS220) gene has been recently associated with schizophrenia and with a novel syndrome characterized by spastic paraplegia, intellectual disability, nystagmus and obesity (SINO syndrome), diseases frequently occurring with ventriculomegaly. Here we show that Kidins220, a transmembrane protein effector of various key neuronal signalling pathways, is a critical regulator of CSF homeostasis. We observe that both KIDINS220 and the water channel aquaporin-4 (AQP4) are markedly downregulated at the ventricular ependymal lining of idiopathic normal pressure hydrocephalus (iNPH) patients. We also find that Kidins220 deficient mice develop ventriculomegaly accompanied by water dyshomeostasis and loss of AQP4 in the brain ventricular ependymal layer and astrocytes. Kidins220 is a known cargo of the SNX27-retromer, a complex that redirects endocytosed plasma membrane proteins (cargos) back to the cell surface, thus avoiding their targeting to lysosomes for degradation. Mechanistically, we show that AQP4 is a novel cargo of the SNX27-retromer and that Kidins220 deficiency promotes a striking and unexpected downregulation of the SNX27-retromer that results in AQP4 lysosomal degradation. Accordingly, SNX27 silencing decreases AQP4 levels in wild-type astrocytes whereas SNX27 overexpression restores AQP4 content in Kidins220 deficient astrocytes. Together our data suggest that the KIDINS220-SNX27-retromer-AQP4 pathway is involved in human ventriculomegaly and open novel therapeutic perspectives.

Transcriptome Response and Spatial Pattern of Gene Expression in the Primate Subventricular Zone Neurogenic Niche After Cerebral Ischemia

The main stem cell niche for neurogenesis in the adult mammalian brain is the subventricular zone (SVZ) that extends along the cerebral lateral ventricles. We aimed at characterizing the initial molecular responses of the macaque monkey SVZ to transient, global cerebral ischemia. We microdissected tissue lining the anterior horn of the lateral ventricle (SVZa) from 7 day post-ischemic and sham-operated monkeys. Transcriptomics shows that in ischemic SVZa, 541 genes were upregulated and 488 genes were down-regulated. The transcription data encompassing the upregulated genes revealed a profile typical for quiescent stem cells and astrocytes. In the primate brain the SVZ is morphologically subdivided in distinct and separate ependymal and subependymal regions. The subependymal contains predominantly neural stem cells (NSC) and differentiated progenitors. To determine in which SVZa region ischemia had evoked transcriptional upregulation, sections through control and ischemic SVZa were analyzed by high-throughput in situ hybridization for a total of 150 upregulated genes shown in the www.monkey-niche.org image database. The majority of the differentially expressed genes mapped to the subependymal layers on the striatal or callosal aspect of the SVZa. Moreover, a substantial number of upregulated genes was expressed in the ependymal layer, implicating a contribution of the ependyma to stem cell biology. The transcriptome analysis yielded several novel gene markers for primate SVZa including the apelin receptor that is strongly expressed in the primate SVZa niche upon ischemic insult.

Membrane Structures Between Craniopharyngioma and the Third Ventricle Floor Based on the QST Classification and Its Significance: A Pathological Study

The aim of this study was to clarify the relationship between craniopharyngiomas (CP) and the third ventricle floor by analyzing the membranes between them. Eight fetal specimens were first examined by hematoxylin and eosin and immunofluorescence staining to determine optimal markers for identifying membrane structures in the sellar region. Then, 17 CP with third ventricle floor involvement that had been removed by total en bloc resection through a transsphenoidal approach were examined. We found that the dura mater, arachnoid membrane, and pia mater could be seen to separate type Q tumors from the third ventricle floor. The arachnoid membrane and pia mater could be seen between type S tumors and the third ventricle floor. Pia mater could be seen between type T tumors and the third ventricle floor; however, at the origin point of the tumor, pia mater could be loosened or replaced by the tumor. Although some type T tumors compressed the third ventricle, the ependymal layer remained intact. Based on these embryonic and pathological data, we suggest that CP are nonneuroepithelial, epi-pia mater, and epi-third ventricle tumors.

Gbx1 and Gbx2 Are Essential for Normal Patterning and Development of Interneurons and Motor Neurons in the Embryonic Spinal Cord

The molecular mechanisms regulating neurogenesis involve the control of gene expression by transcription factors. Gbx1 and Gbx2, two members of the Gbx family of homeodomain-containing transcription factors, are known for their essential roles in central nervous system development. The expression domains of mouse Gbx1 and Gbx2 include regions of the forebrain, anterior hindbrain, and spinal cord. In the spinal cord, Gbx1 and Gbx2 are expressed in PAX2+ interneurons of the dorsal horn and ventral motor neuron progenitors. Based on their shared domains of expression and instances of overlap, we investigated the functional relationship between Gbx family members in the developing spinal cord using Gbx1−/−, Gbx2−/−, and Gbx1−/−/Gbx2−/− embryos. In situ hybridization analyses of embryonic spinal cords show upregulation of Gbx2 expression in Gbx1−/− embryos and upregulation of Gbx1 expression in Gbx2−/− embryos. Additionally, our data demonstrate that Gbx genes regulate development of a subset of PAX2+ dorsal inhibitory interneurons. While we observe no difference in overall proliferative status of the developing ependymal layer, expansion of proliferative cells into the anatomically defined mantle zone occurs in Gbx mutants. Lastly, our data shows a marked increase in apoptotic cell death in the ventral spinal cord of Gbx mutants during mid-embryonic stages. While our studies reveal that both members of the Gbx gene family are involved in development of subsets of PAX2+ dorsal interneurons and survival of ventral motor neurons, Gbx1 and Gbx2 are not sufficient to genetically compensate for the loss of one another. Thus, our studies provide novel insight to the relationship harbored between Gbx1 and Gbx2 in spinal cord development.