Expression of extracellular matrix degrading enzymes during migration of xenografted brain cells.

Proteolytic enzymes, postulated to create an avenue for cell migration by digestion of host extracellular matrix molecules, have been implicated in neoplastic glial cell migration. A similar process is likely to occur in the developing brain. Fetal rabbit brain fragments transplanted into the striatum of the neonatal Shiverer mouse give rise to cells which migrate from the graft site and differentiate into astrocytes and oligodendrocytes. Proteinase expression by transplanted brain cells was studied using immunohistochemistry and in situ hybridization. Immature donor cells expressed the mRNAs for matrix metalloproteinases (MMP) 1 (collagenase) and 3 (stromelysin). Northern blot analysis of rabbit brain showed that MMP-1 in particular is expressed in the immature rabbit cerebrum and down-regulated during maturation. Immature donor cells exhibited immunoreactivity for urokinase plasminogen activator. However, immunoreactivity was also present in maturing neurons. Donor and host astroglia in the vicinity of grafts were immunoreactive for MMP-2 and tissue-type plasminogen activator. This expression may represent a reactive phenomenon, not specifically related to cell migration, by mature astrocytes. Based upon our findings, MMP-1 appears to be a candidate for involvement in migration of immature brain cells in the cerebrum.

Fine structure of astroglial integration into host brain following xenografting.

Previous investigations showed that fragments of fetal rabbit brain transplanted into striatum of neonatal shiverer mouse give rise to cells that migrate through host tissue and differentiate into astroglia and oligodendroglia within 2 weeks. We studied the integration of transplanted astroglia at the ultrastructural level using pre-embedding labeling with a monoclonal antibody which recognizes an epitope associated with rabbit but not mouse glial fibrillary acidic protein. The morphology of early migrating donor cells does not distinguish them from cells arising in host germinal matrix. Once the cells complete their migration they integrate into host brain in a structurally normal manner. Transplanted astroglia form perivascular foot plates with host capillaries. They also send extensive processes into the neuropil where intimate contacts with neurons and synaptic structures are formed. Oligodendroglia send processes to nearby axons where they form normal-appearing myelin. During the rejection process, which may begin at 4 weeks, donor astroglia show evidence of reaction with increased intermediate filament content. Donor cells are attacked by leukocytes, including eosinophils, and subsequently degenerate. We conclude that cross-species transplantation of glial cells can result in entirely normal structural integration into host brain.

Localization of proteinase expression in the developing rabbit brain.

In developing rabbit brain we studied expression of metalloproteinases (MMP) 1 and 3 by in situ hybridization and MMP2 and tissue and urokinase-type plasminogen activators (tPA and uPA) by immunohistochemistry. All are detected in developing cell populations. Mature olfactory bulb neurons express MMP1 and MMP3. uPA is expressed by glial cells during myelination and by mature cortical neurons. MMP2 is expressed by mature subpial and perivascular astrocytes.

[The glial fibrillary acidic protein]. / La protéine gliofibrillaire acide.

Since it was discovered, twenty years ago, the glial fibrillary acidic protein has been the subject of more than 500 publications. The huge interest it has raised up is probably due partly to its abundance in the central nervous system and also, above all, to its cellular specificity which makes it the universally recognized marker of astrocytes. It has been used by biologists as a tool to follow the normal or pathological glia cell differentiation in animal models and human pathology, particularly in the fields of neuropathology and neuro-oncology.

Implantation of rabbit embryo brain fragments into newborn mice: integration and survival of xenogeneic astrocytes.

Brain fragments containing embryonic rabbit glia were implanted into the brains of newborn mice. The hosts developed an astroglial reaction around the transplants and along the needle tracks. Transplant-derived astrocytes were identified in the operated brain by their expression of rabbit GFAP. During the first few days post-implantation (PI) glial cells were exchanged between the transplant and the host. Less than 3 to 5 days PI, the transplant was extensively invaded by host astrocytes. Xenogeneic astroglial cells were first detected 10 days PI in the immediate proximity of the transplant. At 2 to 11 weeks, they could be detected either close to or at distance from the point of implantation. Most often, transplant-derived astrocytes presented a morphology similar to that of neighboring host astrocytes. Xenogeneic glial cells were found to participate in various types of astroglial features: sub-pial, pericapillary, fibrous, and protoplasmic. This morphological integration suggests that they are physiologically integrated, at least to a certain degree, in the host tissue. In spite of their integration into the host, xenogeneic astrocytes disappear after 3 months without signs of an inflammatory reaction.

Survival of astroglial cell lineage from adult brain transplant.

We previously described a transplantation model which enables the selective identification of rabbit astroglial cells in sections of mouse brain tissue. In the present paper, we report that cells of the astroglial lineage from an adult transplant are able to survive after implantation into the brain of an immature host. Surviving xenogenic cells are found outside the graft, forming colonies in the host brain parenchyma. However, after 3 months, transplant-derived astrocytes are no longer detected.

Immunocytochemical study of S-100 protein in human pituitary adenomas.

The S-100 protein was localized by immunocytochemistry in 70 pituitary tumors including 30 prolactin, 16 growth hormone, two corticotropin and 22 non-functioning adenomas. Positive immunostaining was observed in only one case (prolactin adenoma). It is concluded that in functioning and non-functioning pituitary tumors there is no particular involvement of S-100 protein-containing cells, at least under the conditions of this study.

Oligodendroglial expression and deposition of four major myelin constituents in the myelin sheath during development. An in vivo study.

We have studied the sequence of expression in the oligodendrocyte of four myelin constituents: galactosylceramide (GalC), myelin basic protein (MBP), proteolipid protein (PLP) and Wolfgram protein (W1). These investigations were performed on freshly dissociated cell preparations from mouse olfactory bulb and cerebellum before and during early myelinogenesis. Our data showed that the first myelin antigen to be detected in the oligodendrocyte was GalC, followed 24 h later by W1 and after a 5-day time lag (relative to GalC) by MBP. Expression of PLP occurred shortly after that of MBP. This sequence of events was identical in the cerebellum and in the olfactory bulb, but it commenced earlier in the cerebellum (E18) than in the olfactory bulb (P2). Deposition of these components in the nascent myelin sheaths was studied on tissue sections. These histological preparations showed that the temporal order of deposition of the myelin constituents did not correlate with their order of expression in the oligodendrocyte. As judged both by the intensity of the labeling and the number of positive fibers, W1 and MBP were the first antigens to be deposited, followed by PLP and finally by GalC. Furthermore, this deposition process was initiated immediately after completion of expression of these antigens in the oligodendrocyte.

Interspecies identification of astrocytes after intracerebral transplantation.

Species-specificity of the Tp-GFAP 1 (glial fibrillary acidic protein) monoclonal antibodies raised against calf GFAP was established by means of immunochemical techniques. Since it was shown to combine with rabbit GFAP but not with mouse GFAP it allows the characterization of a new experimental model potentially useful in the study of the fate of implanted astrocytes after intracerebral graft of CNS fragments. Preliminary observations indicate that embryonic and newborn rabbit astrocytes are able to survive, express GFAP and migrate when implanted into newborn mouse brain.

Functional maturation of the oligodendrocytes and myelin basic protein expression in the olfactory bulb of the mouse.

The timing of myelin basic protein (MBP) expression and myelin component synthesis by the oligodendrocytes of the olfactory bulb was investigated in the mouse. Immunostaining with an anti-MBP immunoserum and a radioimmunoassay determination of MBP allowed to study the timing of MBP deposition during the development in this structure. Immunostaining of dissociated cells with anti-MBP and anti-galactosylceramide (anti-GC) was used to determine the state of development when these markers become expressed by olfactory bulb oligodendrocytes. Investigations using dissociated cells showed that GC-positive oligodendrocytes are already detected 3 days after birth in the olfactory bulb of the mouse and MBP is expressed 4 days later. Myelinated fibers were not visible on cryostat sections of olfactory bulb before 8 days postnatal. This work has been initiated by observations on the timing of myelination of olfactory bulb oligodendrocytes in transplantation experiments.

Evidence that mouse astrocytes may be derived from the radial glia. An immunohistochemical study of the cerebellum in the normal and reeler mouse.

Astrocytic cells of unusual aspect can be detected in the cerebellum of normal mice during the first 4 weeks of life. They are visualized with anti-GFAP (glial fibrillary acidic protein), anti-S100 and anti-vimentin immune sera. Their perikaryons, located in the white matter or in the granular layer, extend long processes which are inserted onto the pial surface. These cells may be transitional forms between the radial glial cells and some of the differentiated astroglial elements. These unusual astrocytes are more numerous and heavily stained in the reeler mutant than in the normal mouse and it is suggested that our observations signify some degree of glial immaturity in the cerebellum of the mutant.

GFA and S 100 protein levels as an index for malignancy in human gliomas and neurinomas.

Human glia-specific proteins S 100 and GFA were quantitated by use of a rocket immunoelectrophoresis technique with monospecific antisera. No relation was found between the S 100 protein content of an astrocytoma and its degree of neoplasia. However, the lower the GFA protein content of the astrocytoma, the more malignant it was. Similarly, the more malignant a neurinoma was, the lower was its S 100 protein content. Therefore, the levels of these proteins might be used as indexes of neoplastic dedifferentiation.

Circulating immune complexes in multiple sclerosis. Relation to clinical and biological parameters.

Circulating immune complexes were looked for on 38 clinically definite MS (multiple sclerosis) patients compared to 35 other neurological patients and 26 healthy subjects. 29% of the MS sera and 8.6% of the other neurological sera were positive, whereas none of the control sera were positive. These differences are significant. Clinical status was analysed as regards the age at onset, the duration and course of the disease, the disability of the patients and the treatment they received. CSF (cerebrospinal fluid) parameters studied were pleocytosis, concentration of total protein, electrophoresis. The results suggest that IC (immune complex) are more frequent during the first 10 years of the MS disease, in patients with blood-brain barrier damage and in patients without oligoclonal IgG.

Determination of glial fibrillary acidic protein (GFAP) in human brain tumors.

Brain tumors have been tested for their glial fibrillary acidic protein (GFAP) content by means of the rocket electrophoresis technique. Meningiomas and neurinomas were low in GFAP. Metastases had a low level of GFAP except when contaminated with surrounding tissue. Non-nervous tumors such as myeloma, myeloplaxoma and adenocarcinoma gave negative results. More detailed correlations with histological observations have been looked for in glial tumors. Low levels of GFAP were always associated with signs of malignancy such as mitoses and giant or atypical cells, whereas high levels of GFAP were correlated with the presence of well-preserved astrocytes.

Quantitative studies of the brain specific antigens GFA, 14-3-2, synaptin C1, D1, D2, D3 and D5 in jimpy mouse.

Seven antigens specific to the nervous tissue were measured in both Jimpy and control mice. The D5 and the GFA protein, both components of the glia, are strongly increased in the mutant while the neuronal components 14-3-2, synaptin C1, D1, D2 and D3 are unchanged.