Establishment of continuous multiple sclerosis brain cultures after transformation with PML-SV40 virus.

PML-SV40 virus was used to transform cells from explants and monolayer subcultures of human brain derived from biopsies or autopsies of MS cases, as well as from 1 case of Jakob-Creutzfeldt disease (JC), 1 case of amyotrophic lateral sclerosis (ALS) and several cases without CNS disease. The success of transformation depended on the growth condition of the culture at the time of infection but at present at least 14 cell lines, 10 derived from MS, 2 from JC, 1 from ALS and 1 from a normal non-CNS patient are maintained in continuous culture.     

Human brain in tissue culture. I. Acquisition, initial processing, and establishment of brain cell cultures.

This paper details the in vitro techniques used to establish cells in culture from the brains of 40 patients, most of whom had chronic neurologic disease. The clinical and pathologic features of these patients are given. The success in establihsing cell lines was dependent upon the origin of tissue (biopsy vs. autopsy), the site of removal from the brain, and various environmental and technical manipulations in vitro.     

Human brain in tissue culture

Summary Glial fibrillary acidic protein (GFAP) was present in cell cultures derived from human fetal brain tissue as determined by indirect immunofluorescence (IF) and immunoperoxidase (IP) staining using rabbit anti-human GFAP antisera. The IF and IP techniques were comparable in localizing the cytoplasmic distribution and the frequent perinuclear concentration of GFAP in brain cells. The horseradish peroxidase technique was more sensitive and a 1:20–1:40 dilution of anti-GFAP serum could be applied in the initial step of the peroxidase staining as compared to a 1:10 dilution of anti-GFAP serum for IF staining. Sequential studies of subcultivated human fetal brain cell lines by these techniques indicated that some brain cell lines become GFAP-negative rapidly, whereas other cell lines remain GFAP-posifive for no less than ten subcultivations in vitro. GFA protein was never present in any PMLSV₄₀-transformed human brain cells.This study was supported, in part, by Public Health Service Research grants NS-11036, NS-10648, NS-05572, and NS-09779 from the National Institute of Neurological Diseases and Stroke and by a grant from the National Multiple Sclerosis Society     

Human brain in tissue culture. IV. Morphological characteristics.

The morphology of cells from normal and diseased brains and PML-SV40 transformed brain cells grown on glass cover slips in cultures is described. Seven types of cells are identifiable, four of which are probably of mesenchymal origin whereas the remaining three are neurologlial. A classification on the basis of the morphologic features is presented.     

Human brain in tissue culture. II. Studies of long-term cultures.

This paper describes the techniques used to maintain and reconstitute from storage adult human brain cells in culture. Growth characteristics, cell morphology, lifespan, and karyotypic analysis of cell lines derived from patients with multiple sclerosis (MS), non-MS neurologic diseases, and normal brains are compared.     

Generation of human myogenic cell lines by the transformation of primary culture with origin-defective SV40 DNA

The gene transfection technique was applied to establish clonal human skeletal muscle cell lines. DNA of a replication origin-defective mutant of SV40 was transfected into a primary culture of human skeletal muscle by the DNA-calcium phosphate co-precipitation method, and myoblast-derived cells were selected from among the transformed cells and cloned. The myogenic clonal cells exhibited an enhanced growth rate and an unlimited life span, which indicated that a stable supply of a large quantity of cultured human myogenic cells without contaminating fibroblasts was possible. In addition, despite the transformation, the transformed clones retained a certain differentiation ability, that is, they could form multinucleated cells or express a muscle-specific isomer of creatine kinase. These characteristics of transformed myogenic cells should be of great value in studies on the molecular pathologies of various myopathies.     

Lipid synthesis by rat brain microvessel endothelial cells in tissue culture

Lipid synthesis and its regulation by serum lipoproteins at the microvascular blood-brain barrier were studied using primary cultures of microvascular endothelial cells from rat brain. These cells are capable of synthesizing all their lipids (neutral lipids, phospholipids, glycolipids) from the water-soluble compounds, glucose, acetate, acetoacetate and beta-hydroxybutyrate. The ketone bodies, especially acetoacetate, are the preferred substrates for lipid synthesis. The incorporation patterns of acetate, acetoacetate and beta-hydroxybutyrate are very similar, indicating that these precursors contribute to lipid synthesis via the same metabolic route. However, the metabolic pathway is different for glucose, which is preferentially incorporated into phospholipids. The existence of an inverse relationship between lipid synthesis and the serum lipoprotein concentration suggests that cultured cerebral endothelial cells are capable of taking up lipids, principally cholesterol, contained in the serum lipoproteins. Cellular lipids would thus be supplied both by intracellular lipid synthesis and by serum lipoproteins. The difference between cholesterol synthesis rates in cultured cerebral endothelial cells and in isolated brain microvessel cells could be partly explained by the fact that the lipoprotein concentration is much lower in the culture medium than in rat serum.     

Desmosterol in human and experimental brain tumors in tissue culture.

Desmosterol, a possible chemical indicator of brain tumors, was detected in cells of neurogenic, nitrosourea-induced rat tumors (neurinomas and gliomas, C6 cell line) and in human astrocytomas grown in lipid-poor media. A further increase in the amount of cell desmosterol was obtained when triparanol was added to media containing delipidized serum. Cholesterol was replaced almost completely by desmosterol in tumor cells grown in media containing nontoxic levels of 20,25-diazacholesterol. Desmosterol did not accumulate when these inhibitors of desmosterol-reductase were added to culture media containing cholesterol and other lipids (whole fetal calf serum). The results demonstrate that tumors of the nervous system grown in tissue culture are capable of sterol synthesis, and indicate that a central mechanism of cholesterol synthesis is operative in these cells, which may be related to the availability of exogenous cholesterol. It is concluded that these findings are relevant to clinical studies on the use of cholesterol inhibitors as tools for the detection of brain tumor activity.     

Human immunodeficiency virus infection in microglia: correlation between cells infected in the brain and cells cultured from infectious brain tissue.

In acquired immunodeficiency syndrome, the lesions of the central nervous system in association with the human immunodeficiency virus are thought to be related to an infection of microglia, although no studies are available in which cultured and physiological characteristics of microglia cells infected in vivo have been examined. In this report, we used brain tissue from a child dying of human immunodeficiency virus infection and show that microglia cells were the main cell population being infected. Moreover, isolated macrophage-like cells from fresh brain material revealed a close resemblance to peripheral blood macrophages in their content of surface and intracellular antigens. No virus particles or viral antigens were produced by these cells during the first week of cultivation. Productive infection was readily apparent, however, by day 30. This finding illustrates the slow nature of the virus life cycle in these cells and the minimal cytopathology that accompanied the infection.     

SV-40 virus-induced neoplastic transformation of hamster brain cells in vitro. Studies with scanning and transmission electron microscopy

Neoplastic transformation of one-day-old hamster brain cells was produced by infection with SV-40 virus and verified by phase contrast microscopy, growth in semisolid media, and intracranial tumor production after inoculation of the cells into other one-day-old hamsters. Transformed cells were studied by transmission and scanning electron microscopy. The numerous alterations in cell surface structure and in nuclear and cytoplasmic organization suggest a marked increase in cell metabolism and in the rate of mitosis and cell division. Cilia with a nine-to-zero pattern of microtubule doublets were present in cells with intermediate size filaments which stained for glial fibrillary acidic protein. The findings indicate that infection of one-day-old hamster brain cells in culture by SV-40 virus results in their transformation to a neoplastic state and the transformed cells are differentiating neoplastic astrocytes.     

Development of antioxidant enzymes in rat brain and in reaggregation culture of fetal brain cells.

The development of antioxidant enzymes in rat brain and reaggregation cultures of fetal brain cells was studied from embryonic day 15 to postnatal day 45. Both in vivo and in culture, the copper-zinc superoxide dismutase activity first increased and then decreased with age, whereas the manganese superoxide dismutase activity increased throughout the period. Catalase showed a maximum activity at day 5 after birth, thereafter decreasing to adult level around day 30, both in vivo and in culture. The glutathione peroxidase activity increased from the first week after birth and reached adult level at day 45. In culture, the activity of this enzyme was slightly lower. The good correlation between the development of the antioxidant enzymes in vivo and in culture suggests that reaggregation cultures might be a valuable system for studying defense mechanisms against free radicals in the brain.     

Hyperosmotic arabinose solutions open the tight junctions between brain capillary endothelial cells in tissue culture

Noradrenergic, serotoninergic and peptidergic nerves have been demonstrated in perivascular plexuses of vasa nervorum of sympathetic, parasympathetic and somatic nerve trunks. 5-Hydroxytryptamine-, vasoactive intestinal polypeptide- and substance P-containing fibers were found by immunohistochemistry to variable extents in whole mounts of the epineurium of sciatic, vagus and paravertebral sympathetic chains of rabbits. Innervation increased with age. This suggests an hitherto unsuspected role for these vasoactive substances in normal blood flow to nerves and in the genesis of experimental and human neuropathies.     

Fluorescent labeling of dissociated fetal cells for tissue culture.

The ability to pre-label cells used in transplantation experiments would have the potential benefits of identification of cell type and associated processes and the analysis of graft migration in the host. We have used an in vitro tissue culture system as a model to test several fluorescent dyes for this application. Fetal rat hippocampal tissue (E17-E18) was dissociated and incubated in the presence of carboxyfluorescein ester (CFSE), rhodamine-B dextran amine (RBD), DiI, or rhodamine-labeled latex microspheres. Cells were cultured in defined medium for up to 1 month. Cells labeled with CFSE were initially bright but faded over several days. RBD labeled the soma of cells, but fluorescence intensity was lost over a period of a few weeks. Cells labeled with DiI possessed brilliant staining of neuronal processes for weeks. Latex microspheres brightly labeled the soma but not the processes of neurons; fluorescent debris and sterility were problems with this label. We conclude that CFSE and DiI have significant potential usefulness in vitro as markers of cell viability and process formation with mammalian fetal CNS cells, whereas RBD is much less permanent. Latex microspheres may be suitable for pre-labeling of cells for transplantation if purification and sterility can be enhanced over present preparations.     

Morphological, immunocytochemical and biological characteristics of experimental rabbit brain tumors in tissue culture.

Brain tumors were induced in 3-month-old rabbits of either sex by repeated intravenous injections of N-methyl-N-nitrosourea. Twelve brain tumors (6 pleomorphic gliomas, 5 grade 2--3 astrocytomas, 1 grade 2--3 oligodendroglioma) were established in culture and, with the exception of 2 neoplasms, were propagated in vitro as permanent cell lines. The glial nature of all cell lines was ascertained at several passage levels by testing the cells for the production of S-100 and GFA. It could be shown that most cells of all lines fluoresced positively for the S-100 protein, albeit differences in intensity of fluorescence were clearly noted between cells of the same culture and between different cultures. In general, astrocytoma cell lines had the strongest fluorescence. Pleomorphic glioma cells but especially astrocytoma cells reacted positively also for the GFA protein. Surprisingly enough, isolated cells of the oligodendroglioma line also showed evidence of GFA production. Exposure of cultures of rabbit glioma cells to db-cAMP for 8--10 hr resulted in inhibition of cell proliferation and stimulation of process formation. Furthermore, positive fluorescence for the S-100 and GFA proteins was more intense in cells treated with db-cAMP than in untreated cells. The latter observation may indicate that production and/or accumulation of glial proteins also was enhanced during the stationary phase of cell cultures.     

Human microglial cells: characterization in cerebral tissue and in primary culture, and study of their susceptibility to HIV-1 infection.

Neuropathological studies have shown that human immunodeficiency virus type 1-infected cells within the brain express several markers characteristic of macrophages and could either be microglial cells, or monocytes invading the CNS, or both. To better define the target cells of human immunodeficiency virus type 1 within the brain, we have studied human microglial cells, both in vivo and in vitro, and compared them to monocytes for their antigenic markers and their susceptibility to human immunodeficiency virus type 1 infection. Brain-derived macrophages were isolated from primary cortical and spinal cord cultures obtained from 8 to 12-week-old human embryos. The isolated cells presented esterase activity, phagocyted zymosan particles, expressed several (Fc receptors, and CD68/Ki-M7 and CD11b/CR3 receptors) of the macrophagic antigenic markers, and appeared to be resident microglial cells from human embryonic brain. Conversely, brain-derived macrophages did not express antigens CD4, CD14, or CD68/Ki-M6, which are easily detected on freshly isolated monocytes. Using these antigenic differences between isolated microglial cells and monocytes, we have observed that two populations of macrophages could be individualized. In the normal adult brain, microglial cells were numerous in both the gray and the white matter. The infrequent cells sharing antigens with monocytes were found almost exclusively around vessels. In 8 to 12-week-old human embryos, microglial cells were found in both the parenchyma and the germinative layer. Cells sharing antigens with monocytes were only found at the top of and inside the germinative layer. In brain tissue from patients with human immunodeficiency virus type 1 encephalitis, cells sharing antigens with monocytes are abundant not only around the vessels but also in the parenchyma. In double-labeling experiments, human immunodeficiency virus type 1-infected cells showed monocyte antigens. Finally, microglial cells also differ from monocytes in their in vitro susceptibility to human immunodeficiency virus type 1 infection; after stimulation by r-TNF alpha or GmCSF, monocytes but not microglial cells can replicate human immunodeficiency virus type 1. This in vitro difference in human immunodeficiency virus type 1 susceptibility between monocytes and microglial cells together with the presence of monocytic antigens within the brain tissue of human immunodeficiency virus type 1-infected patients suggest that human immunodeficiency virus type 1-infected cells within the brain are either monocytes that have crossed the blood-brain barrier and spread through the tissue or perivascular microglial cells that, after phagocyting infected blood lymphocytes, subsequently contain viral antigen and migrate to brain tissue.     

Morphological diversity of ependymal cells in tissue culture

Ependymal cells were visualized in primary cultures of cerebral cortex from rat using an immunohistochemical staining technique. Five different morphological subtypes of cuboidal ependyma were recognized: 1) round, 2) triangular, 3) columnar, 4) cone- and spindle-shaped, and 5) large pleomorphic cells. These cells varied in size and almost all possessed cilia. Two distinct forms of tanycyte ependyma were detected based on the presence of cilia. These features reflect a significant level of development of the ependymal cells in culture and may correspond to functional diversity within this group.