carbocyanines and Demyelinating-Diseases

The helix-loop-helix transcription factor Olig2 is essential for lineage determination of oligodendrocytes. Differentiation of stem cells into oligodendrocytes and transplanting them is a novel strategy for the repair of different demyelination diseases. Dental pulp stem cells (DPSCs) are of great interest in regenerative medicine due to their potential for repairing damaged tissues. In this study, DPSCs were isolated from human third molars and transfected with the human Olig2 gene as a differentiation inducer for the oligodendrogenic pathway. Following the differentiation procedure, the expression of Sox2, NG2, PDGFRα, Nestin, MBP, Olig2, Oct4, glial fibrillary acidic protein and A2B5 as stage-specific markers was studied by real-time RT-qPCR, immunocytochemistry and Western blot analysis. The cells were transplanted into a mouse model of local sciatic damage by lysolecithin as a model for demyelination. Oligodendrocyte progenitor cells (OPCs) actively remyelinated and recovered the lysolecithin-induced damages in the sciatic nerve as revealed by treadmill exercise, the von Frey filament test and hind paw withdrawal in response to a thermal stimulus. Recovery of behavioral reflexes occurred 2-6 weeks after OPC transplantation. The results demonstrate that the expression of Olig2 in DPSCs reduces the expression of stem cell markers and induces the development of oligodendrocyte progenitors as revealed by the emergence of oligodendrocyte markers. DPSCs could be programmed into oligodendrocyte progenitors and considered as a simple and valuable source for the cell therapy of neurodegenerative diseases.

Topics: Adult; Animals; Basic Helix-Loop-Helix Transcription Factors; Blotting, Western; Carbocyanines; Cell Differentiation; Cell Lineage; Cell Separation; Cell Shape; Demyelinating Diseases; Dental Pulp; Disease Models, Animal; Humans; Immunohistochemistry; Lysophosphatidylcholines; Mice; Nerve Tissue Proteins; Oligodendrocyte Transcription Factor 2; Oligodendroglia; Real-Time Polymerase Chain Reaction; RNA, Messenger; Sciatic Nerve; Stem Cell Transplantation; Stem Cells; Touch; Young Adult

Myelination is one of the fundamental biological processes in the development of vertebrate nervous system. Disturbance of myelination is found to be associated with progression in many neurological diseases such as multiple sclerosis. Tremendous efforts have been made to develop novel therapeutic agents that prevent demyelination and/or promote remyelination. These efforts need to be accompanied by the development of imaging tools that permit direct quantification of myelination in vivo. In this work, we describe a novel near-infrared fluorescence imaging technique that is capable of direct quantification of myelination in vivo. This technique is developed based on a near-infrared fluorescent probe, 3,3'-diethylthiatricarbocyanine iodide (DBT) that readily enters the brain and specifically binds to myelinated fibers. In vivo imaging studies were first conducted in two animal models of hypermyelination and hypomyelination followed by longitudinal studies in the cuprizone-induced demyelination/remyelination mouse model. Quantitative analysis suggests that DBT is a sensitive and specific imaging probe of myelination, which complements other current myelin-imaging modalities and is of low cost.

Topics: Analysis of Variance; Animals; Benzothiazoles; Carbocyanines; Corpus Callosum; Cuprizone; Demyelinating Diseases; Disease Models, Animal; Longitudinal Studies; Mice; Mice, Inbred C57BL; Mice, Neurologic Mutants; Mice, Transgenic; Myelin Basic Protein; Myelin Proteolipid Protein; Myelin Sheath; Permeability; Protein Binding; Proto-Oncogene Proteins c-akt; Spectroscopy, Near-Infrared; Time Factors

In multiple sclerosis, the central nervous system is lesioned through invasion of plaque-forming inflammatory cells, primarily contributing to immune attack of myelin and oligodendrocytes. In this report we address the possible activation and differentiation of central nervous system stem cells following such immunological insults in a well-characterized rat model of multiple sclerosis characterised by spinal cord pathology. Dye-labeled central nervous system stem cells, residing within the ependymal layer of the central canal responded to the multiple sclerosis-like conditions by proliferation, while some of the migrating stem cell-derived cells expressed markers typical for oligodendrocytes (04) and astrocytes (glial fibrillary acidic protein, GFAP) in the demyelinated area. Our results indicate that regenerative stem cell activation following immunoactivity is different from that after trauma, exemplified by the slower time course of stem cell proliferation and migration of progeny, in addition to the ability of the stem cell-derived cells to express oligodendrocyte markers. Finally, deleterious effects of macrophages on the stem cell population were evident and may contribute to the depletion of the stem cell population in neuroinflammatory disorders.

Topics: Animals; Bromodeoxyuridine; Carbocyanines; Cell Count; Demyelinating Diseases; Disease Models, Animal; Ectodysplasins; Encephalomyelitis, Autoimmune, Experimental; Ependyma; Female; Fluorescent Dyes; Freund's Adjuvant; Glial Fibrillary Acidic Protein; Indoles; Macrophages; Membrane Proteins; Microscopy, Confocal; Myelin Proteins; Myelin Sheath; Myelin-Associated Glycoprotein; Myelin-Oligodendrocyte Glycoprotein; O Antigens; Rats; Rats, Inbred Strains; Spinal Cord; Stem Cells; Time Factors

In the present paper, Dil-labeled myelin-forming cells were traced after their transplantation at a distance from a lysolecithin induced lesion in the adult wild-type and shiverer mouse spinal cord. Optical and ultrastructural observations indicate that after their transplantation, Dil-labeled Schwann cells and oligodendrocyte progenitors were found at the level of the graft as well as at the level of the lesion thus confirming that myelin-forming cells were able to migrate in the adult lesioned CNS (Gout et al., Neurosci Lett 87:195-199, 1988). Between the graft and the lesion, labeled Schwann cells and oligodendrocyte progenitors were absent in the gray matter, but were found as previously described, in specific locations (Baron-Van Evercooren et al., J Neurosci Res 35:428-438, 1993; Vignais et al., J Dev Neurosci 11:603-612, 1993). Both cell types were found along blood vessel walls and more precisely in the Virchow-Robin perivascular spaces. They were identified in the meninges among meningeal cells, collagen fibers, or occasionally in direct contact with the basement membrane forming the glia limitans. In addition to these findings, three major observations were made. In the ependymal region, myelin-forming cells were localized between or at the basal pole of ependymocytes. While Dil-labeled oligodendrocyte progenitors were noted to migrate along the outer surface of myelin sheats in CNS wild-type and shiverer white matter, Schwann cells were excluded from this structure in the wild-type mouse spinal cord. Moreover, in the shiverer mouse, migrating Schwann cells did not seem to interact directly with myelin sheats nor with mature oligodendrocytes. Finally, both cell types were seen to invade extensively the spinal peripheral roots. Our ultrastructural observations clearly suggest that multiple cell-cell and cell-substrate interactions rule the migration of myelin-forming cells in the adult CNS infering that multiple mechanisms are involved in this process.

Topics: Animals; Carbocyanines; Cell Movement; Cell Transplantation; Cells, Cultured; Demyelinating Diseases; Lysophosphatidylcholines; Mice; Mice, Inbred Strains; Myelin Sheath; Oligodendroglia; Rats; Schwann Cells; Spinal Cord; Stem Cell Transplantation; Stem Cells