Inhibition of fibrocyte differentiation by serum amyloid P

Wound healing and the dysregulated events leading to fibrosis both involve the proliferation and differentiation of fibroblasts and the deposition of extracellular matrix. Whether these fibroblasts are locally derived or from a circulating precursor population is unclear. Fibrocytes are a distinct population of fibroblast-like cells derived from peripheral blood monocytes that enter sites of tissue injury to promote angiogenesis and wound healing. We have found that CD14(+) peripheral blood monocytes cultured in the absence of serum or plasma differentiate into fibrocytes within 72 h. We purified the factor in serum and plasma that prevents the rapid appearance of fibrocytes, and identified it as serum amyloid P (SAP). Purified SAP inhibits fibrocyte differentiation at levels similar to those found in plasma, while depleting SAP reduces the ability of plasma to inhibit fibrocyte differentiation. Compared with sera from healthy individuals and patients with rheumatoid arthritis, sera from patients with scleroderma and mixed connective tissue disease, two systemic fibrotic diseases, were less able to inhibit fibrocyte differentiation in vitro and had correspondingly lower serum levels of SAP. These results suggest that low levels of SAP may thus augment pathological processes leading to fibrosis. These data also suggest mechanisms to inhibit fibrosis in chronic inflammatory conditions, or conversely to promote wound healing.     

Effect of horse serum on neural cell differentiation in tissue culture

The effects of various concentrations of horse serum on dissociated mouse glial precursor cells in colony cultures were evaluated. High concentrations (20% or more) favored cell attachment but inhibited cell proliferation and differentiation, whereas lower concentrations (5% to 10%) favored cell proliferation and differentiation. In fetal bovine serum the cells did not attach to culture surfaces to the same degree nor did they achieve the same level of differentiation as in corresponding concentrations of horse serum.     

Effect of horse serum on neural cell differentiation in tissue culture

Summary The effects of various concentrations of horse serum on dissociated mouse glial precursor cells in colony cultures were evaluated. High concentrations (20% or more) favored cell attachment but inhibited cell proliferation and differentiation, whereas lower concentrations (5% to 10%) favored cell proliferation and differentiation. In fetal bovine serum the cells did not attach to culture surfaces to the same degree nor did they achieve the same level of differentiation as in corresponding concentrations of horse serum. Portions of this work were presented at the 29th Annual Meeting of the Tissue Culture Association, Denver, Colorado, June 10–14, 1978 (1). This investigation was supported by Grants MA and MT 4235 from the Medical Research Council of Canada.     

Effect of Echinacea augustifolia extract on cell viability and differentiation in mammary epithelial cells

Echinacea spp. are popularly used as an herbal medicine or food supplement for enhancing the immune system and activating biological property in different tissues. In this study we show the biological effect of Echinacea augustifolia extract on cell viability and cell differentiation in mammary epithelial cell lines. These effects have been observed in two different cell line derived from mouse (HC11) and bovine (BME-UV). Echinacea extract enhanced cell liability from 100 to 1000 ng/ml in association with growth factors, epidermal growth factor (EGF) or insulin, but also without EGF (p<0.05) up to 37% vs. control. This effect may be modulated by MAPK and Akt activation that Echinacea extract treatment increased and/or by a reduction of caspase 3 activity, showed a dose–response decrease after Echinacea treatment. Finally Echinacea extract was able to increase (p<0.05) at 100 ng/ml β-casein expression in association with PRL (5 μg/ml). These data demonstrate that Echinacea angustifolia extract can stimulate mammary epithelial cell physiology and may be considered a candidate to support mammary gland activity during a mammogenetic and lactogenetic state.     

Effect of oxytocin on neuroblastoma cell viability and growth

Oxytocin, released in response to different physiological stimuli, could play a key role in reducing stress reaction. It was suggested that it has protective effect against inflammation and consequences of oxidative stress. Mechanisms how oxytocin effects mediated in the brain tissue are unclear. In this study, oxytocin effect on cell growth and neuronal viability was examined. Human neuroblastoma (SH-SY5Y and SK-N-SH) and glioblastoma (U87MG) cells were exposed to different concentrations of oxytocin for 12-96 h. Potential protective effect of oxytocin treatment was investigated after exposing cells to oxidative stress using hydrogen peroxide (50 mM, 2 h) or 6-hydroxydopamine (25 μM, 24 h). Cell proliferation was measured by cell counting and cell viability was examined by MTT assay. Protein expression of selected neurotrophic factors was measured as an additional parameter. Oxytocin (1 μM) significantly increased cell number in all three cell types. Viability of SH-SY5Y cells was increased in the presence of oxytocin without significant effect of dose (0.01-1 μM). Cell death induced by hydrogen peroxide was not prevented by incubation with oxytocin. Oxytocin pretreatment blunted neurotoxin 6-OHDA reduction of cell viability in SH-SY5Y cells. Oxytocin (1 μM, 12 h) elevated amount of total proteins without increasing levels of brain-derived neurotrophic factor and neurotrophic growth factor. In conclusion, oxytocin increases growth and viability of neuroblastoma and glioblastoma cells without activation of neurotrophic factors. Oxytocin does not have protective effect in oxidative stress; however, it might be important for neuroprotection to dopaminergic neurons. Its proliferative effect might be important in native cell life, euplastic processes, and tumor progression.     

Alternating current electric field effects on neural stem cell viability and differentiation

Methods utilizing stem cells hold tremendous promise for tissue engineering applications; however, many issues must be worked out before these therapies can be routinely applied. Utilization of external cues for preimplantation expansion and differentiation offers a potentially viable approach to the use of stem cells in tissue engineering. The studies reported here focus on the response of murine neural stem cells encapsulated in alginate hydrogel beads to alternating current electric fields. Cell viability and differentiation was studied as a function of electric field magnitude and frequency. We applied fields of frequency (0.1–10) Hz, and found a marked peak in neural stem cell viability under oscillatory electric fields with a frequency of 1 Hz. We also found an enhanced propensity for astrocyte differentiation over neuronal differentiation in the 1 Hz cultures, as compared to the other field frequencies we studied. Published 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Effect of trisodium citrate treatment on hybridoma cell viability

Trisodium citrate has been widely used to dissolve calcium alginate beads in order to estimate cell concentration in the beads. To obtain an accurate measurement of viable cell concentration in calcium alginate beads, the effect of trisodium citrate solutions on hybridoma cell viability was studied with regard to stage of growth and trisodium citrate concentration. The cells in the decline phase of growth were more sensitive to 30 minutes of trisodium citrate treatment than the cells in the exponential phase of growth. The cell viability did not decrease rapidly during citrate treatment regardless of cell growth phase and trisodium citrate concentration in the range of 1–1.5%. By using the commercially available sodium alginate, Keltone LV, dissolution time can be kept short enough (below 5 minutes) to keep the effect of trisodium citrate negligible to cell viability.     

Effect of lycopene on cell viability and cell cycle progression in human cancer cell lines

ABSTRACT: BACKGROUND: Lycopene, a major carotenoid component of tomato, has a potential anticancer activity in many types of cancer. Epidemiological and clinical trials rarely provide evidence for mechanisms of the compound's action, and studies on its effect on cancer of different cell origins are now being done. The aim of the present study was to determine the effect of lycopene on cell cycle and cell viability in eight human cancer cell lines. METHODS: Human cell lines were treated with lycopene (1-5 uM) for 48 and 96 h. Cell viability was monitored using the method of MTT. The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick labeling (TUNEL) and by DAPI. RESULTS: Our data showed a significant decrease in the number of viable cells in three cancer cells lines (HT-29, T84 and MCF-7) after 48 h treatment with lycopene, and changes in the fraction of cells retained in different cell cycle phases. Lycopene promoted also cell cycle arrest followed by decreased cell viability in majority of cell lines after 96 h, as compared to controls. Furthermore, an increase in apoptosis was observed in four cell lines (T-84, HT-29, MCF-7 and DU145) when cells were treated with lycopene. CONCLUSIONS: Our findings show the capacity of lycopene to inhibit cell proliferation, arrest cell cycle in different phases and increase apoptosis, mainly in breast, colon and prostate lines after 96 h. These observations suggest that lycopene may alter cell cycle regulatory proteins depending on the type of cancer and the dose of lycopene administration. Taken together, these data indicated that the antiproliferative effect of lycopene was cellular type, time and dose-dependent. KEY WORDS: lycopene, cancer, bioactive compounds, cell cycle.     

Effect of maternal serum on viability and function of early human placental explants

Summary Fetal bovine serum (FBS) is frequently used to supplement chemically defined media such as Ham’s F10 when studying placental explant cultures. However in vitro production of hormones is usually declining by the 2nd or 3rd day and is short-lived (7 to 10 days). In this study we explored the use of human maternal serum (HMS) from early gestation as the medium supplement to Ham’s F10. Early placental hormone production was compared using two concentrations of FBS and HMS. On Day 3 of incubation, progesterone production in 10% HMS was 12-fold increased over that in 10% FBS, estradiol production was increased 10-fold, and βhCG production more than 3-fold. When the serum concentrations were increased to 40%, the results in all cases were similar to those at 10%. Preliminary characterization studies revealed that the stimulatory activity of HMS is heat-labile, neither extractable into organic solvent (diethyl ether) nor dialyzable, suggesting that it is protein in nature. In a long-term incubation, compared with FBS (7 days), HMS permitted survival of culture up to 30 days, judged both histologically and biochemically. We conclude that HMS provides substance(s), probably protein in nature, not present in FBS or non-pregnant human serum, which are important for human placental viability and function in vivo.     

Effect of calcium chloride treatment on hybridoma cell viability and growth

In order to minimize hybridoma cell damage during calcium alginate entrapment, the effect of calcium chloride treatment on hybridoma cell viability and growth was studied in terms of calcium chloride concentration and treatment time. The cell viability as measured by trypan blue exclusion did not decrease rapidly during the first hour of calcium chloride treatment regardless of calcium chloride concentrations used (1.3 and 1.5%). However, 1.3% calcium chloride solution appeared to be more detrimental to the cells than 1.5% calcium chloride solution. The cells in 1.3% calcium chloride solution lost their viability faster than the cells in 1.5% calcium chloride solution. In addition, when the cells treated with calcium chloride were inoculated into spinner flasks containing IMDM with 10% fetal calf serum, the cells treated with 1.3% calcium chloride solution showed a longer lag phase than the cells treated with 1.5% calcium chloride solution.     

Effect of elastin peptides on cell proliferation]

Elastin peptides were shown to act on a cell membrane receptor coupled to a G-protein, phospholipase C, and its activation increases IP3 and DAG and opens receptor-dependent Ca(++)-channels. As some growth factors also produce similar modifications in intracellular Ca++, we wanted to explore the effect of elastin peptides on cell proliferation using 3H-thymidine incorporation and cell counting. The concentration of peptides needed for the stimulation of cell proliferation varied between large limits (1 microgram/ml to 10 mg/ml) according to the origin of the cells and the nature of the peptides. The proliferation of CCL 39 chinese hamster lung fibroblasts was enhanced in a dose-dependent fashion in the concentration range of 3 to 10 mg/ml. The proliferation of human skin fibroblasts was enhanced in the concentration range of 0.5 to 3.3 mg/ml and inhibited at higher concentrations. This effect depended little on the average molecular weight (MW) of the peptide preparation, high MW peptides (average 75 kDa) and lower MW peptides (average MW 10 kDa) were both efficient approximately to the same extent. It appears probable that only a small fraction of these peptides possesses this growth promoting property; other sequences might have the opposite effect. The conformation of the peptides may also play an important role. Human sera contain circulating elastin peptides in the concentration range of 1.0 to 10 micrograms/ml, increasing in obstructive arteriopathies and in some hyperlipidemias. It appears therefore that the above findings may have physiopathological significance in the regulation of cell proliferation in normal and pathological conditions.     

Evaluation of human MSCs cell cycle, viability and differentiation in micromass culture

Mesenchymal stem cells (MSCs) have the potential to differentiate into distinct mesenchymal tissue cells. They are easy to expand while maintaining their undifferentiated state, which suggests that these cells could be an attractive cell source for tissue engineering of cartilage. In vitro high density micromass culture has been widely used for chondrogenesis induction. Our objective was to investigate human MSCs cell cycle, viability and differentiation in these conditions. Therefore, to induce human MSCs chondrogenesis, micromasses were cultured in the presence of transforming growth factor-beta1 in serum free medium for 21 days. Cell cycle, cell viability and cell phenotype were analyzed by flow cytometry. From day 0 to 7, the G0/G1 phase increased, whereas the S phase decreased gradually, but cell cycle phases (S, G0/G1 and G2/M) did not significantly change after day 7. Less than 10% of cells were apoptotic, but no necrosis was observed, even at day 21. We observed a decrease in CD90 and CD105 expression, from day 0 to 21. In conclusion, our results demonstrate a good viability of human MSCs in micromass culture during the whole period of culture. Moreover, micromass culture allowed human MSCs to be synchronized at the G0/G1 phase, while their phenotype suggested some degree of differentiation.     

Glucagon-like peptides: regulators of cell proliferation,differentiation, and apoptosis

Peptide hormones are secreted from endocrine cells and neurons and exert their actions through activation of G protein-coupled receptors to regulate a diverse number of physiological systems including control of energy homeostasis, gastrointestinal motility, neuroendocrine circuits, and hormone secretion. The glucagon-like peptides, GLP-1 and GLP-2 are prototype peptide hormones released from gut endocrine cells in response to nutrient ingestion that regulate not only energy absorption and disposal, but also cell proliferation and survival. GLP-1 expands islet mass by stimulating pancreatic beta-cell proliferation and induction of islet neogenesis. GLP-1 also promotes cell differentiation, from exocrine cells or immature islet progenitors, toward a more differentiated beta-cell phenotype. GLP-2 stimulates cell proliferation in the gastrointestinal mucosa, leading to expansion of the normal mucosal epithelium, or attenuation of intestinal injury in experimental models of intestinal disease. Both GLP-1 and GLP-2 exert antiapoptotic actions in vivo, resulting in preservation of beta-cell mass and gut epithelium, respectively. Furthermore, GLP-1 and GLP-2 promote direct resistance to apoptosis in cells expressing GLP-1 or GLP-2 receptors. Moreover, an increasing number of structurally related peptide hormones and neuropeptides exert cytoprotective effects through G protein-coupled receptor activation in diverse cell types. Hence, peptide hormones, as exemplified by GLP-1 and GLP-2, may prove to be useful adjunctive tools for enhancement of cell differentiation, tissue regeneration, and cytoprotection for the treatment of human disease.     

Foetal calf serum and dexamethasone effects on Vero cell growth and differentiation

Vero cells were cultured without foetal calf serum (FCS), with 10% FCS, 10% FCS plus dexamethasone (DEX) or 20% FCS for 48, 120 or 240 h. The cells were analysed by a growth curve, cytochemical and immunocytochemical (anti-cellular fibronectin or anti-collagen IV) methods. In 48 h Vero cells produced fibronectin and collagen IV. All samples showed basophilic cytoplasm indicating high protein synthesis. The growth of metachromatic multicellular masses was induced by DEX. The Vero cells produced collagen IV with 10 and 20% FCS, and also cells which did not have this activity (without FCS or with 10% FCS + DEX). The multicellular masses induced by DEX were rich in fibronectin. DEX induced differentiation and the expression of collagen IV and fibronectin in Vero cells. This work was carried out to evaluate the possible therapeutic effects of glucocorticoids as inducers of cell differentiation.     

Small acidic peptides and peptidomimetic molecules: cell growth and differentiation.

Small phosphorylated chromatin peptides exert a homeostatic regulation on gene expression which causes a strong inhibition of RNA synthesis and growth of neoplastic and fast-growing cells and a remarkable activation of metabolic pathways slowed down in ageing. By biochemical and mass spectrometry analysis, some molecular models of these peptides have been designed and synthesised. Recent studies show that it is possible to find peptidomimetic structures, such as citric acid, able to reproduce the antiproliferative effect. The mechanism of action has been investigated and partially clarified.     

Recombinant expression of goat milk serum amyloid A: preliminary studies of the protein and derived peptides on macrophage phagocytosis

Serum Amyloid A3 (SAA3) protein is a member of a complex group of acute phase and constitutive proteins which have been related to several immune functions. Bovine milk SAA3 (M-SAA3) has been described to have a unique N-terminal TFLK motif responsible for up regulating mucin expression in the intestine lumen and therefore a protective gastrointestinal role. cDNA sequences encoding the protein goat M-SAA3 were successfully cloned from milk, mammary gland tissue and liver, expressed despite observed toxicity and purified as a soluble protein. Sequence analyses of the milk and liver derived forms revealed a non mammary-restricted common N-terminal TFLR motif, unlike that described for bovine M-SAA3. Serum derived forms of SAA have been described to opsonize Gram-negative bacteria facilitating their phagocytosis by circulating macrophages or intestinal epithelial cells. However, no reports about a possible opsonic mechanism of the SAA3 isoforms have been described. Recombinant protein but not peptides encompassing the TFLR region increased blood and milk macrophage interaction and uptake of bacteria reported as number of bacteria per 100 macrophages and percentage of macrophages containing one or more bacteria. gMSAA3-derived peptides did not show any effect on phagocytosis. This would indicate that the TFLK-like region responsible for the up-regulation of mucins in the intestine is not the functional part of g-MSAA3 in promoting macrophage phagocytosis.     

Effect of age on T cell differentiation.

A brief overview of the area of T cell aging is presented by first discussing the age-related changes in T cell activities, and then by focusing attention on the possible mechanisms that may be responsible for the decline. Present evidence indicates that thymic involution precedes and therefore may be responsible for the age-dependent decline in the ability of the immune system to generate functional T cells. At this time, it appears that the primary effect of thymic involution is on a T cell differentiation pathway affecting the more mature T cells first with time, and then the less mature T cells. Thus, the thymus may be the aging clock for the immune system. Further studies should be centered around processes regulating growth and atrophy of the thymus.