HS-P Cells Research Articles

FGF2 and ET1 promote human fetal striatal neuroblasts survival in hypoxic conditions

Fetal striatal transplantation emerged as a new strategy to promote reparative responses in Huntington’s disease (HD) patients1. Mechanisms that support neuroblasts survival and replenishment of damaged cells within the HD brain in hypoxia remain to be elucidated. This study investigated how human fetal striatal neuroblasts (HSP cells) respond to hypoxia, using the hypoxia-mimetic agent cobalt chloride (CoCl2)2. We analyzed CoCl2 effect on hypoxia-related proteins, such as HIF-1α and VEGF, and on a neuroprotective factor, such as Seladin-1. Moreover, we evaluated FGF2 (50 ng/ml) and ET1 (100 nM) proliferative/survival effects in HSP cells in normoxic and hypoxic conditions. These growth factors could be important mediators under pathological conditions for striatal neuroblasts function and response to hypoxia. Dose-response experiments with increasing concentration of CoCl2 (50-750 um) showed an increase of HSP cell proliferation at 24-48h, with maximal effects observed at 400 um, while cell survival was impaired at 72h. Hypoxia increased protein expressions of HIF-1α and VEGF, whereas decreased Seladin-1 levels. FGF2 and ET1 significantly stimulated HSP cells proliferation both in normoxic and hypoxic condition, counteracting the apoptotic CoCl2 effect at 72h. FGF2 and ET1 neuroprotective effect was abolished by the selective inhibition of their receptors (FGFR1, ETA and ETB). In particular, ET1 stimulated HSP cells survival through ETA receptor in normoxic condition and through ETB receptor during hypoxia. Our results support the idea that FGF2 and ET1 promote neurogenesis and survival of HSP cells, through receptor-mediated mechanisms, when grafted into the hypoxic HD brain.

Differential Effects of Trypanosoma brucei gambiense and Trypanosoma brucei brucei on Rat Macrophages

Mammalian immune responses to Trypanosoma brucei infection are important to control of the disease. In rats infected with T. brucei gambiense (Wellcome strain; WS) or T. brucei brucei (interleukin-tat 1.4 strain [ILS]), a marked increase in the number of macrophages in the spleen can be observed. However, the functional repercussions related to this expansion are not known. To help uncover the functional significance of macrophages in the context of trypanosome infection, we determined the mRNA levels of genes associated with an increase in macrophage number or macrophage function in WS- and ILS-infected rats and in cultured cells. Specifically, we assayed mRNA levels for macrophage colony stimulating factor (M-CSF), granulocyte macrophage colony stimulating factor (GM-CSF), and macrophage migration inhibitory factor (MIF). Upregulation of GM-CSF and MIF mRNA levels was robust in comparison with changes in M-CSF levels in ILS-infected rats. By contrast, upregulation of M-CSF was more robust in WS-infected rats. The phagocytic activity in macrophages harvested from ILS-infected rat spleens, but not WS-infected spleens, was higher than that in macrophages from uninfected rats. These results suggest that macrophages of WS-infected rats change to an immunosuppressive type. However, when WS or ILS is cocultured with spleen macrophages or HS-P cells, a cell line of rat macrophage origin, M-CSF is upregulated relative to GM-CSF and MIF in both cell types. Anemia occurs in ILS-, but not WS-infected, rats. Treatment of spleen macrophages or HS-P cells cocultured with ILS with cobalt chloride, which mimics the effects of anemia-induced hypoxia, led to downregulation of M-CSF mRNA levels, upregulation of GM-CSF and MIF, and an increase in phagocytic activity. However, the effect of cobalt chloride on spleen macrophages and HS-P cells cocultured with WS was restricted. These results suggest that anemia-induced hypoxia in ILS-infected rats stimulates the immune system and activates macrophages.

Inhibition of Interleukin-12 Production by Trypanosoma brucei in Rat Macrophages

The immune response of a host infected with Trypanosoma brucei is modulated by trypomastigotes. We examined the changes in cytokine production in T. brucei gambiense (Wellcome strain; WS) infected rats and the influence on production of interleukin (IL)-12 by macrophages. The blood concentration of interferon-gamma, tumor necrosis factor-alpha, and IL-10 increased beginning the second day after infection. However, an increase in IL-12p40 was not observed until 4 days after infection. When spleen macrophages and Kupffer cells harvested from uninfected rats and HS-P cells (a rat macrophagelike cell line) were cocultured with WS, IL-12p40 production did not change. When HS-P cells were cultured with WS, transport of nuclear factor-kappaB into the nucleus increased. Levels of macrophage colony-stimulating factor (M-CSF) and granulocyte macrophage colony-stimulating factor mRNA in the spleens and livers of WS-infected rats were high in comparison with uninfected rats, suggesting that the WS promotes macrophage proliferation. The level of IL-12p40 mRNA in HS-P cells cocultured with WS increased in response to transfection with a small interfering RNA against M-CSF or addition of anti-M-CSF antibody. These results suggest that the WS inhibits IL-12p40 mRNA production by promoting production of macrophage colony-stimulating factor by macrophages.

Effects of Lipopolysaccharide on a Macrophage-like Cell Line (HS-P) from a Rat Histiocytic Sarcoma

Lipopolysaccharide (LPS) is a major modulator of macrophage functions. To characterize a newly established rat histiocytic sarcoma-derived cell line (HS-P), immunophenotypic changes and cellular growth responses of HS-P cells exposed to LPS were investigated and compared with those of MT-9 cells isolated from a rat malignant fibrous histiocytoma. MT-9 cells have somewhat histiocytic features, because occasional cells react to rat macrophage-specific antibodies. Addition of LPS to cultured HS-P cells increased the numbers of cells immunopositive to ED1 (rat macrophage-specific antibody) and ED2 (rat histiocyte-specific antibody) and stimulated the phagocytosis of latex beads, whereas LPS-treated MT-9 cells did not show such immunophenotypic changes. LPS-treated HS-P cells showed enhanced immunoÍlabelling of α-smooth muscle actin, suggesting a possible modulation of macrophages towards myofibroblastic cells. To evaluate cellular growth after the addition of LPS or fetal bovine serum, DNA synthesis was examined by measuring tritiated thymidine incorporation, and the mRNA expression of c- jun and c- myc (immediate early genes in the cell cycle) was examined by Northern blot analysis. In HS-P cells, the addition of serum greatly increased DNA synthesis and induced high expression of c- jun and c- myc; in contrast, LPS markedly depressed DNA synthesis and reduced the expression of c- jun and c- myc. HS-P cells were more sensitive than MT-9 cells to the growth-promoting effect of serum and the growth-inhibiting effect of LPS. The study demonstrated that HS-P cells are highly LPS-responsive, indicating that they would be useful for studies of macrophage functions.

Macrophage-like Cell Line (HS-P) from a Rat Histiocytic Sarcoma

With future exploration of macrophage properties in mind, we established a novel cell line (HS-P) from a transplantable histiocytic sarcoma, derived originally from a tumour in an aged F344 rat. HS-P was subjected to 70 serial passages, in which the mean doubling time was 15·7 h. The cells, which were round, oval or polygonal in shape, were arranged in a compact sheet. They reacted to varying degrees for lysosomal enzymes (acid phosphatase and non-specific esterase) and with the following antibodies: ED1/ED2 (rat macrophage/histiocyte-specific), OX6 (rat MHC class II-specific), lysozyme antibody and α1-antichymotrypsin antibody. Electron microscopically, HS-P cells showed lysosomes and prominent cell projections. These findings indicated that the cultured cells were macrophage-like. Syngeneic rats inoculated subcutaneously or intraperitoneally with HS-P cells invariably developed sarcomatous tumours consisting of monomorphic mononuclear cells, which exhibited cytochemical properties similar to those of cultured HS-P cells. Bioassay and reverse transcription-polymerase chain reaction methods revealed that tumour necrosis factor-α increased on addition of lipopolysaccharide (LPS), indicating that HS-P cells remained LPS-responsive. HS-P cells may prove to be a useful tool for in-vitro studies of macrophage function.

A new antioxidant compound H-290/51 attenuates heat shock protein (HSP 72 kD) response, edema and cell injury following acute heat exposure. An experimental study using light and electron microscopy in the rat

Rats exposed to 4 h heat stress at 38°C exhibited upregulation of heat shock protein (HSP 72 kD) expression in several brain regions associated with brain edema and cell injury. Pretreatment with a new anti-oxidant compound H-290/51 (50 mg/kg, per os, 30 min before stress) significantly attenuated HSP expression, brain edema and cell injury. These results suggest that oxidative stress associated with brain edema plays important roles in HSP expression, not reported earlier.

Expression of a unique plastid-localized heat-shock protein is genetically linked to acquired thermotolerance in wheat

We have used a combination of molecular and classical genetic approaches to delineate the relationship between a specific HSP member and cell viability under heat stress. Using recombinant inbred lines (RILs) of wheat, derived from a cross of the thermotolerant cultivar ‘Mustang’ and the thermosusceptible cultivar ‘Sturdy,’ we have identified a unique HSP and a differentially expressed cDNA sequence, both related to the plastid-localized HSP26 gene family, that are closely associated with acquired thermotolerance in wheat. An isoform of HSP26 was synthesized under heat stress in all examined thermotolerant RILs and ‘Mustang’, and was absent in all examined thermosusceptible RILs and ‘Sturdy.’ Using a modified differential-display method, we have also identified a gene-specific cDNA sequence that is similar to other known members of the wheat HSP26 gene family and is selectively expressed in ‘Mustang’ and most of the examined thermotolerant RILs, but not expressed in ‘Sturdy’ and all the thermosusceptible RILs. These results suggest a genetic linkage between the acquired thermotolerance trait and the differential expression of a unique member of the HSP26 gene family.