Myelinated fibers of the mouse spinal cord after a 30-day space flight

© 2016, Pleiades Publishing, Ltd.Myelinated fibers and myelin-forming cells in the spinal cord at the L3–L5 level were studied in C57BL/6N mice that had spent 30 days in space. Signs of destruction of myelin in different areas of white matter, reduction of the thickness of myelin sheath and axon diameter, decreased number of myelin-forming cells were detected in “flight” mice. The stay of mice in space during 30 days had a negative impact on the structure of myelinated fibers and caused reduced expression of the markers myelin-forming cells. These findings can complement the pathogenetic picture of the development of hypogravity motor syndrome

Electrophysiological Heterogeneity of Fast-Spiking Interneurons: Chandelier versus Basket Cells

In the prefrontal cortex, parvalbumin-positive inhibitory neurons play a prominent role in the neural circuitry that subserves working memory, and alterations in these neurons contribute to the pathophysiology of schizophrenia. Two morphologically distinct classes of parvalbumin neurons that target the perisomatic region of pyramidal neurons, chandelier cells (ChCs) and basket cells (BCs), are generally thought to have the same "fast-spiking" phenotype, which is characterized by a short action potential and high frequency firing without adaptation. However, findings from studies in different species suggest that certain electrophysiological membrane properties might differ between these two cell classes. In this study, we assessed the physiological heterogeneity of fast-spiking interneurons as a function of two factors: species (macaque monkey vs. rat) and morphology (chandelier vs. basket). We showed previously that electrophysiological membrane properties of BCs differ between these two species. Here, for the first time, we report differences in ChCs membrane properties between monkey and rat. We also found that a number of membrane properties differentiate ChCs from BCs. Some of these differences were species-independent (e.g., fast and medium afterhyperpolarization, firing frequency, and depolarizing sag), whereas the differences in the first spike latency between ChCs and BCs were species-specific. Our findings indicate that different combinations of electrophysiological membrane properties distinguish ChCs from BCs in rodents and primates. Such electrophysiological differences between ChCs and BCs likely contribute to their distinctive roles in cortical circuitry in each species. © 2013 Povysheva et al

Neuroprotective action of new pyrimidine derivatives on rat spinal cord injury

Effects of the systemic administration of xymedon and its derivatives-L-ascorbate and para-aminobenzoate 1,2-dihydro-4,6-dimethyl-l-(2-hydroxyethyl) pyrimid-2-one (compounds 29D and 34D, respectively) - have been studied on a contusion model (Th8 level) of spinal cord injury in rats. Experiments showed the impact of treatment on recovery of motor function, spinal cord tissue safety, population and phenotypic characteristics of astrocytes in the zones of gray and white matter. Xymedon produced a stimulating effect on recovery of the locomotor function. In this respect, compounds 29D and 34D were more effective than xymedon, although no significant differences between the action of compounds 29D and 34D was observed. Each of the three investigated pyrimidine derivatives significantly reduced the total area of pathologic cavities in spinal cord. In this respect, compounds 29D and 34D were also more effective than xymedon. Compound 29D exhibited a more pronounced effect in the dorsal root entry zone (DREZ), while compound 34D more significantly supported preservation of tissue in the ventral horns (VHs). Within 60 days after administration of compounds of 29D and 34D, the number of GFAP+ astrocytes in gray matter zones decreased as compared to the group treated with xymedon, and the expression of this marker protein of intermediate filaments decreased. In the white matter, the number of GFAP+ cells increased under the influence of compound 29D and decreased under the action of compound 34D. Differences between the effects of compounds 29D and 34D (on the background of their equal influence on recovery of the locomotor function) may be indicative of different cellular and molecular mechanisms of action, in agreement with data on their action on tissue safety

The Role of Parvalbumin-positive Interneurons in Auditory Steady-State Response Deficits in Schizophrenia

© The Author(s) 2019. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Despite an increasing body of evidence demonstrating subcellular alterations in parvalbumin-positive (PV+) interneurons in schizophrenia, their functional consequences remain elusive. Since PV+ interneurons are involved in the generation of fast cortical rhythms, these changes have been hypothesized to contribute to well-established alterations of beta and gamma range oscillations in patients suffering from schizophrenia. However, the precise role of these alterations and the role of different subtypes of PV+ interneurons is still unclear. Here we used a computational model of auditory steady-state response (ASSR) deficits in schizophrenia. We investigated the differential effects of decelerated synaptic dynamics, caused by subcellular alterations at two subtypes of PV+ interneurons: basket cells and chandelier cells. Our simulations suggest that subcellular alterations at basket cell synapses rather than chandelier cell synapses are the main contributor to these deficits. Particularly, basket cells might serve as target for innovative therapeutic interventions aiming at reversing the oscillatory deficits.Peer reviewe

Characterization of spinal cord glial cells in a model of hindlimb unloading in mice

© 2014 IBRO. Exposure to microgravity has been shown to result in damaging alterations to skeletal muscle, bones, and inner organs. In this study, we investigated the effects of microgravity by using a hindlimb unloading model (HUM) in mice. The characteristics of the lumbar spinal cords of HUM mice 30. days after hindlimb unloading were examined. Morphometric analysis showed reductions of the total area, gray matter, and white matter by 17%, 20%, and 12%, respectively. Myelinated fibers in the white matter showed prominent myelin destruction. Analysis of the number of glial fibrillary acidic protein (GFAP+)/S100 calcium-binding protein B (S100B-), GFAP+/S100B+, and GFAP-/S100B+ astrocytes in the ventral horn (VH), central channel area (CC), dorsal root entry zone (DREZ), main corticospinal tract (CST), and ventral funiculi (VF) showed that the number of GFAP+/S100B- astrocytes was increased in the DREZ and CST of HUM mice. Additionally, GFAP+/S100B+ cell numbers were significantly decreased in the VH and CST but did not differ in the CC or DREZ of HUM mice, as compared with the control. The numbers of GFAP-/S100B+ cells were significantly reduced only in the VH of HUM mice. Moreover, the number of ionized calcium-binding adaptor molecule 1 (Iba1+) microglia cells was significantly increased in the CC and DREZ of HUM mice. In control mice, homeobox protein HoxB8 (HoxB8+) cells were found only in the CC; in contrast, HoxB8+ cells were observed in all studied areas in HUM mice, with the greatest number found in the CC. Genome-wide transcriptome analysis of the lumbar spinal cords of HUM mice showed decreased expression of genes encoding myelin, extracellular matrix, cytoskeleton, and cell adhesion proteins. Real-time polymerase chain reaction (PCR) confirmed reductions in the expression of mpz, pmp2, pmp22, and prx genes, which are involved in myelination, as well as decreases in the levels of genes encoding extracellular matrix molecules, including glycoproteins (matrix gla protein (MGP), osteoglycin (OGN), microfibrillar associated protein 5 (MFAP), and collagen, type IV, alpha 1 (COL4A)), proteoglycans (perlecan (heparan sulfate proteoglycan) (HSPG)), and metalloproteinases (lysyl oxidase (LOX)). Thus, our results showed that hindlimb unloading caused decreases in gray and white matter areas, changes in gene expression, alterations in myelination, and phenotypic modifications in glial cells in the lumbar spinal cords of mice

Spinal cord molecular and cellular changes induced by adenoviral vector- and cell-mediated triple gene therapy after severe contusion

© 2017 Izmailov, Povysheva, Bashirov, Sokolov, Fadeev, Garifulin, Naroditsky, Logunov, Salafutdinov, Chelyshev, Islamov and Lavrov. The gene therapy has been successful in treatment of spinal cord injury (SCI) in several animal models, although it still remains unavailable for clinical practice. Surprisingly, regardless the fact that multiple reports showed motor recovery with gene therapy, little is known about molecular and cellular changes in the post-traumatic spinal cord following viral vector- or cell-mediated gene therapy. In this study we evaluated the therapeutic efficacy and changes in spinal cord after treatment with the genes encoding vascular endothelial growth factor (VEGF), glial cell-derived neurotrophic factor (GDNF), angiogenin (ANG), and neuronal cell adhesion molecule (NCAM) applied using both approaches. Therapeutic genes were used for viral vector- and cell-mediated gene therapy in two combinations: (1) VEGF+GDNF+NCAM and (2) VEGF+ANG+NCAM. For direct gene therapy adenoviral vectors based on serotype 5 (Ad5) were injected intrathecally and for cell-mediated gene delivery human umbilical cord blood mononuclear cells (UCB-MC) were simultaneously transduced with three Ad5 vectors and injected intrathecally 4 h after the SCI. The efficacy of both treatments was confirmed by improvement in behavioral (BBB) test. Molecular and cellular changes following post-traumatic recovery were evaluated with immunofluorescent staining using antibodies against the functional markers of motorneurons (Hsp27, synaptophysin, PSD95), astrocytes (GFAP, vimentin), oligodendrocytes (Olig2, NG2, Cx47) and microglial cells (Iba1). Our results suggest that both approaches with intrathecal delivery of therapeutic genes may support functional recovery of post-traumatic spinal cord via lowering the stress (down regulation of Hsp25) and enhancing the synaptic plasticity (up regulation of PSD95 and synaptophysin), supporting oligodendrocyte proliferation (up regulation of NG2) and myelination (up regulation of Olig2 and Cx47), modulating astrogliosis by reducing number of astrocytes (down regulation of GFAP and vimetin) and microglial cells (down regulation of Iba1)

Pyrimidine Derivative Ameliorates Spinal Cord Injury via Anti-apoptotic, Anti-inflammatory, and Antioxidant Effects and by Regulating Rho GTPases

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. One of the most important strategies for the treatment of spinal cord injury is searching for new and effective pharmacological neuroprotectors and regeneration stimulators. The derivatives of pyrimidine are universal stimulators of the regeneration of various tissues as they support the recovery of nervous structures. The protective effect of the cocrystal of 1,2-dihydro-4,6-dimethyl-1-(2-hydroxyethyl)-pyrimidinone-2 with para-aminobenzoic acid (compound conjugate III, CCIII) was explored on a rat model with a contusion spinal cord injury. Injection of CCIII significantly reduced the expression of tumor necrosis factor α (TNF-α), inhibited the synthesis of myeloperoxidase (MPO), matrix metalloproteinase 9 (MPP9), cyclooxygenase-2 (COX2), and macrophage marker CD68, and increased the level of superoxide dismutase 1 (SOD1). Additionally, the expression of caspase-7 markers in the damaged tissue decreased under the action of CCIII. Treatment with the CCIII maintained a population of Olig2-positive myelin-forming cells at 30 days post-injury. The detected therapeutic effect is comparable with that of riluzole

Upregulation of proteoglycans in the perilesion perimeter in ventral horns after spinal cord injury

© 2019 Elsevier B.V. Spinal cord injury (SCI) results in pronounced focal tissue damage with subsequent formation of a glial scar that blocks axon regeneration and regrowth. Cellular changes and the composition of the extracellular matrix in regions distal from the injured area remain poorly characterized. In the present study, in the spinal cord distal to the damaged area (perilesion perimeter) there were minimal gross histological changes, but there were pronounced alterations in the extracellular proteoglycans even at 30 days after SCI. These abnormalities coincided with the appearance of reactive astrocytes and a reduction in main astrocytic glutamate transporter 1. Proteoglycan levels exhibited different kinetics and changes after SCI in areas near neuronal cell bodies and in areas distal from them. The results of the study suggest that SCI induces widespread changes in the spinal cord that may be responsible for neuronal dysfunction far from the damaged area and further aggravation of the SCI

Pyrimidine Derivative Ameliorates Spinal Cord Injury via Anti-apoptotic, Anti-inflammatory, and Antioxidant Effects and by Regulating Rho GTPases

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. One of the most important strategies for the treatment of spinal cord injury is searching for new and effective pharmacological neuroprotectors and regeneration stimulators. The derivatives of pyrimidine are universal stimulators of the regeneration of various tissues as they support the recovery of nervous structures. The protective effect of the cocrystal of 1,2-dihydro-4,6-dimethyl-1-(2-hydroxyethyl)-pyrimidinone-2 with para-aminobenzoic acid (compound conjugate III, CCIII) was explored on a rat model with a contusion spinal cord injury. Injection of CCIII significantly reduced the expression of tumor necrosis factor α (TNF-α), inhibited the synthesis of myeloperoxidase (MPO), matrix metalloproteinase 9 (MPP9), cyclooxygenase-2 (COX2), and macrophage marker CD68, and increased the level of superoxide dismutase 1 (SOD1). Additionally, the expression of caspase-7 markers in the damaged tissue decreased under the action of CCIII. Treatment with the CCIII maintained a population of Olig2-positive myelin-forming cells at 30 days post-injury. The detected therapeutic effect is comparable with that of riluzole

Myelinated fibers of the mouse spinal cord after a 30-day space flight

© 2016, Pleiades Publishing, Ltd.Myelinated fibers and myelin-forming cells in the spinal cord at the L3–L5 level were studied in C57BL/6N mice that had spent 30 days in space. Signs of destruction of myelin in different areas of white matter, reduction of the thickness of myelin sheath and axon diameter, decreased number of myelin-forming cells were detected in “flight” mice. The stay of mice in space during 30 days had a negative impact on the structure of myelinated fibers and caused reduced expression of the markers myelin-forming cells. These findings can complement the pathogenetic picture of the development of hypogravity motor syndrome