Developmental expression and differentiation-related neuron-specific splicing of metastasis suppressor 1 (Mtss1) in normal and transformed cerebellar cells

Background: Mtss1 encodes an actin-binding protein, dysregulated in a variety of tumors, that interacts with sonic hedgehog/Gli signaling in epidermal cells. Given the prime importance of this pathway for cerebellar development and tumorigenesis, we assessed expression of Mtss1 in the developing murine cerebellum and human medulloblastoma specimens. Results: During development, Mtss1 is transiently expressed in granule cells, from the time point they cease to proliferate to their synaptic integration. It is also expressed by granule cell precursor-derived medulloblastomas. In the adult CNS, Mtss1 is found exclusively in cerebellar Purkinje cells. Neuronal differentiation is accompanied by a switch in Mtss1 splicing. Whereas immature granule cells express a Mtss1 variant observed also in peripheral tissues and comprising exon 12, this exon is replaced by a CNS-specific exon, 12a, in more mature granule cells and in adult Purkinje cells. Bioinformatic analysis of Mtss1 suggests that differential exon usage may affect interaction with Fyn and Src, two tyrosine kinases previously recognized as critical for cerebellar cell migration and histogenesis. Further, this approach led to the identification of two evolutionary conserved nuclear localization sequences. These overlap with the actin filament binding site of Mtss1, and one also harbors a potential PKA and PKC phosphorylation site. Conclusion: Both the pattern of expression and splicing of Mtss1 is developmentally regulated in the murine cerebellum. These findings are discussed with a view on the potential role of Mtss1 for cytoskeletal dynamics in developing and mature cerebellar neurons

Canalis cruropopliteus - the overlooked canal of Wenzel Gruber.

It is widely known that the popliteal fossa and the lower leg are connected by a canal, containing the neuro-vascular bundle to the posterior leg region, containing the tibial nerve and the posterior tibial artery and veins.The existence of this canal has not been duly recognized in literature, even though it has been named by Wenzel Gruber in 1871, and its contents, walls, entrance, and exits have been extensively described by him in 1878. In the present paper, we would like to pay a homage to the work of this prominent anatomist, which retains its significance for contemporary surgical practice. The cruropoplital canal, canalis cruropopliteus, as named by him, and having been assigned a multitude of terms in practice, deserves to regain its eponymous name - Gruber's canal. The history, and the anatomy with its clinical implications are discussed herein. We hereby recommend that the original name of this canal be included in anatomical textbooks and specialized literature

Roscovitine, an experimental CDK5 inhibitor, causes delayed suppression of microglial, but not astroglial recruitment around intracerebral dopaminergic grafts.

Inhibitors of cell cycle proteins are known to reduce glial activation and to be neuroprotective in a number of settings. In the context of intracerebral grafting, glial activation is documented to correlate with graft rejection. However, the effects of modification of glial reactivity following grafting in the CNS are poorly understood. Moreover, it is not completely clear if the glial cells themselves trigger the rejection process, or are they secondarily activated. The present study investigated the effect of microglial inhibition by the cyclin-dependant kinase 5 (CDK5) inhibitor roscovitine following intracerebral transplantation in the rodent model of Parkinson's disease. Single cell suspension of rat E14 ventral mesencephalic tissue was transplanted to the dopamine-depleted striatum of unilaterally 6-hydroxydopamine (6-OHDA) lesioned male Sprague-Dawley rats. Experimental animals received injections of roscovitine (20 mg/kg) or a vehicle solution three times following the procedure. Immunohistochemistry was carried out on Day 7 and Day 28 to quantitatively describe the glial reaction adjacent to grafts. The data confirm that systemic roscovitine treatment significantly reduced microglial recruitment adjacent to the grafts on Day 28, without exhibiting significant effects on astroglia. However, this was not found to correlate with elevated numbers of neurons in the grafts. Moreover, microglial reaction surrounding grafts was less pronounced compared to control animals, subjected to the mechanical influence only, even without roscovitine treatment. Our results are the first to show the effect of cell cycle inhibition in the context of neuronal transplantation. The findings suggest that microglial activation around intracerebral grafts can be modified pharmacologically. However, the results do not confirm direct neuroprotective effects of cell cycle inhibition after intracerebral transplantation. Reducing microglial recruitment around grafts could be beneficial by reducing inflammation-related degenerative processes. Sparing astrocytes in the same time provides transplanted cells with essential trophics and support. We consider microglial inhibition to be a possible approach for reducing later graft-related complications

Astrogliosis has Different Dynamics after Cell Transplantation and Mechanical Impact in the Rodent Model of Parkinson‘s Disease

Background: Transplantation of fetal mesencephalic tissue is a well-established concept for functional reinnervation of the dopamine-depleted rat striatum. However, there is no extensive description of the glial response of the host brain following this procedure. Aims: The present study aimed to quantitatively and qualitatively analyse astrogliosis surrounding intrastriatal grafts and compare it to the reaction to mechanical injury with the transplantation instrument only. Study Design: Animal experimentation. Methods: The standard 6-hydroxydopamine-induced unilateral model of Parkinson’s disease was used. The experimental animals received transplantation of a single-cell suspension of E14 ventral mesencephalic tissue. Control animals (sham-transplanted) were subjected to injury by the transplantation cannula, without injection of a cell suspension. Histological analyses were carried out 7 and 28 days following the procedure by immunohistochemistry assays for tyrosine hydroxylase and glial fibrillary acidic protein. To evaluate astrogliosis, the cell density and immunopositive area were measured in distinct zones within and surrounding the grafts or the cannula tract. Results: Statistical analysis revealed that astrogliosis in the grafted striatum increased from day 7 to day 28, as shown by a significant change in both cell density and the immunopositive area. The cell density increased from 816.7±370.6 to 1403±272.1 cells/mm2 (p<0.0001) аnd from 523±245.9 to 1164±304.8 cells/mm2 (p<0.0001) in the two zones in the graft core, and from 1151±218.6 to 1485±210.6 cells/mm2 (p<0.05) for the zone in the striatum immediately adjacent to the graft. The glial fibrillary acidic protein-expressing area increased from 0.3109±0.1843 to 0.7949±0.1910 (p<0.0001) and from 0.1449±0.1240 to 0.702±0.2558 (p<0.0001) for the same zones in the graft core, and from 0.5277±0.1502 to 0.6969±0.1223 (p<0.0001) for the same area adjacent to the graft zone. However, astrogliosis caused by mechanical impact only (control) did not display such dynamics. This finding suggests an influence of the grafted cells on the host’s glia, possibly through cross-talk between astrocytes and transplanted neurons. Conclusion: This bidirectional relationship is affected by multiple factors beyond the mechanical trauma. Elucidation of these factors might help achieve better functional outcomes after intracerebral transplantation

Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells-6

<p><b>Copyright information:</b></p><p>Taken from "Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells"</p><p>http://www.biomedcentral.com/1471-213X/7/111</p><p>BMC Developmental Biology 2007;7():111-111.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2194783.</p><p></p>deep cerebellar mass is relatively devoid of signal, as is the external granule cell layer. The latter can be readily recognized as a dense band at the surface in panel B, which shows counterstaining with Hoechst 33342. : At p3 (C), p5 (D) and p8 (E, F), staining can be unambiguously attributed to cells in the inner part of the external granule cell layer, granule cells in the inner granule cell layer, and Purkinje neurons, which show an increasingly strong signal in the perikaryon. Note that the outer part of the EGL and the (prospective) white matter are devoid of signal. : Between postnatal day 15 (G, H) and 21 (I), granule cells in the (internal) granule cell layer cease to express Mtss1. : Adult. Staining is limited to Purkinje cell perikarya. All sections were obtained from the central vermis, except the one shown in panel I, which originates from the lateral vermis, and are cut in the sagittal plane. Anterior is to the left. Bar (in A, J) = 125 μm for panels D, E and insert in C; 250 μm for panels A, B, C, F, H and I; 500 μm for panels G and K; and 1 mm for panel J

Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells-5

<p><b>Copyright information:</b></p><p>Taken from "Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells"</p><p>http://www.biomedcentral.com/1471-213X/7/111</p><p>BMC Developmental Biology 2007;7():111-111.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2194783.</p><p></p>ructures were compared using the Vector Alignment Search Tool (VAST), and visualized with Cn3D 4.1. Alignment is color-coded (red, high), except for the region containing the nuclear localization signal, which is marked yellow to facilitate orientation. : The putative nuclear localization signals (NLS; red, basic amino acids) in the IMD are marked on the chain of the IMD domain pointing to the left, whereas the putative export signal is marked white on the chain pointing to the right. Potential target sites for phosphokinases within/close to the NLS are marked green, whereas the remaining amino acids in the NLS are marked blue (see Fig 5B for sequence details). Panel B was generated using the SwissPDB viewer

Schematic view of the organization of the murine Mtss1 gene based on Ensemble entry ENSMUSG00000022353

<p><b>Copyright information:</b></p><p>Taken from "Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells"</p><p>http://www.biomedcentral.com/1471-213X/7/111</p><p>BMC Developmental Biology 2007;7():111-111.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2194783.</p><p></p> The 5' and 3' UTRs (dark boxes) are not drawn to scale, nor are the intronic regions. Comparison of the murine gene with that of the rat (ENSRNOG00000009001; transcript ENSRNOT00000023505) further suggests that the region labeled here as exon 15 may contain an additional, 108 bp long intron (I, marked in light gray) which would result in the division of exon 15 into two exons of 354 and 239 bps, respectively. Also, the length of exon 14 may either encompass 163 (ENSMUST00000080371) or 208 bp (ENSMUST00000036782). The 45 bps in question are located C-terminal and alternatively form part of the intron separating exons 14 and 15. Regions covered by the in situ hybridization probes used are labeled by horizontal lines A and B. Arrows mark positions of primers used (black arrows, forward primers; open arrows, reverse primers). Schematic view of the derived protein. The N-terminal IMD domain and the C-terminal WH2 domain are shown as gray boxes. The localization of the putative nuclear import (I) and export (E) motives are indicated as black and white boxes, respectively. Expression of Mtss1 splice variants in the early postnatal and adult murine cerebellum. Use of primers located in exons 7 and 13 (primers 2, 5; panel C) reveals the existence of 4 splice variants (the band representing exon combination 11/12/12a/13 reproduces only very weakly here) in the developing and adult cerebellum, as does the use of primers located in exons 11 and 13 (primers 4, 5; panel D). Note that the relative intensity in particular of the band representing splice variants comprising exons 11/12/13 and 11/12a/13 varies during development. The band labeled gapdh is a loading control. Numbers indicate days postnatal; Ad, adult. The arrow indicates a spurious amplificate from an unrelated sequence: This was verified by sequencing, as were the products labeled as bands 11/12/12a/13, 11/12/13, 11/12a/13 and 11/13

Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells-3

<p><b>Copyright information:</b></p><p>Taken from "Developmental expression and differentiation-related neuron-specific splicing of (Mtss1) in normal and transformed cerebellar cells"</p><p>http://www.biomedcentral.com/1471-213X/7/111</p><p>BMC Developmental Biology 2007;7():111-111.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2194783.</p><p></p>oblastoma samples D86, D978, D82, D1401, and D1062; lanes H1, H2: fetal human cerebellar samples R1626 and R1628. Lane C is a negative control. The band indicative of the splice variant containing exons 11/12a/12/13 is hardly visible in this reproduction. : In DAOY (D) and D-283Med medulloblastoma cell lines, bands representing the splice variants 11/12/13 and 11/13 predominate. Note absence of the band indicative of the splice variant 11/12a/13, which should comigrate with the prominent band of sample 10 shown for comparison. Lane C is a negative control