UV irradiation activates JNK and increases alphaI(I) collagen gene expression in rat hepatic stellate cells

Hepatic stellate cells (HSCs) become activated into myofibroblast-like cells during the early stages of hepatic injury associated with fibrogenesis. The subsequent dysregulation of alphaI(I) collagen gene expression is a central pathogenetic step during the development of cirrhosis. Our recent study in rat HSCs (Davis, B. H., Chen, A., and Beno, D. (1996) J. Biol. Chem. 271, 11039-11042) found that ERK1,2 activation might be required for maximal alphaI(I) collagen gene expression. However, the role of the parallel JNK cascade in regulating alphaI(I) collagen gene expression was unknown. In this study, we initially found that UV irradiation of HSCs activated JNK but not ERK1,2. Furthermore, UV irradiation increased endogenous alpha I(I) collagen mRNA abundance and stimulated alpha I(I) collagen gene transcription in HSCs. The effect of the activation of JNK and Jun on alpha I(I) collagen gene expression was further evaluated via transfection of chloramphenicol acetyltransferase reporter plasmids with various sizes of truncated 5' upstream promoter sequence (UPS) of the alphaI(I) collagen gene. This revealed that dominant negative transcription factor JUN suppressed alpha I(I) collagen gene transcription in HSCs maintained in media with 20% serum and constitutively activated JUN increased alphaI(I) collagen gene transcription in HSCs cultured in media with 0.4% serum. UV activated JNK utilized a distal GC box in the 5'-UPS of the collagen gene to regulate gene transcription. This observation was confirmed by site-directed mutagenesis. In co-transfection experiments, the col-chloramphenicol acetyltransferase reporter with a mutagenized GC box was not suppressed by dn-JUN and was not stimulated by activated JUN or by UV irradiation. Southwestern blotting analyses and gel shift assays with basic transcription element-binding protein antiserum suggested that the GC box was bound by basic transcription element-binding protein, a recently described DNA-binding protein. In conclusion, the current study combined with our previous report suggests that ERK1,2 and JNK cascades regulate alphaI(I) collagen expression in HSCs through different regions of the 5'-UPS of the gene. The distal GC box in the 5'-UPS of the alphaI(I) collagen gene may play a central role in receiving extracellular signals through the JNK pathway.

Detection of fetal red cells in fetomaternal hemorrhage using a fetal hemoglobin monoclonal antibody by flow cytometry

BACKGROUND

The laboratory determination of the level of fetal cells in maternal circulation remains an important support in the obstetrical management of women with suspected uterine trauma and in the proper dose administration of anti-D for prevention of Rh hemolytic disease of the newborn. Limitations in the sensitivity and precision of the widely used manual Kleihauer-Betke test have prompted an increased utilization of flow cytometric methods for fetal cell detection in maternal blood samples.

STUDY DESIGN AND METHODS

Murine monoclonal antibodies directed against fetal hemoglobin (HbF) were developed, conjugated to fluorescein isothiocyanate, and used in a multiparametric flow cytometric assay developed for the quantitation of fetal red cells. A rapid intracellular staining method using brief glutaraldehyde fixation and Triton X-100 permeabilization prior to monoclonal antibody incubation was developed, along with optimization of the flow cytometric analysis protocol for the analysis of 50,000 cells. The performance of the assay was assessed for linearity and precision and correlated with the Kleihauer-Betke acid elution method.

RESULTS

The anti-HbF flow cytometric method showed good correlation with the Kleihauer-Betke method (r2 = 0.86) and superior precision with a CV < 15 percent for blood samples with > 0.1 percent fetal cells. Analysis of 150 blood samples from nonpregnant adults, including individuals with elevated HbF due to hemoglobinopathies and hereditary persistence of HbF, gave a mean value of 0.02 percent fetal cells, and all results were less than 0.1 percent.

CONCLUSIONS

The anti-HbF flow cytometric method for detection of fetal cells offers a simple, reliable, and more precise alternative to the Kleihauer-Betke manual technique for the assessment of fetomaternal hemorrhage. The method has additional potential applications for the study of HbF levels or frequency of adult red cells with low levels of HbF (F cells) in individuals with hemoglobinopathies.

E-box-binding repressor is down-regulated in hepatic stellate cells during up-regulation of mannose 6-phosphate/insulin-like growth factor-II receptor expression in early hepatic fibrogenesis

Hepatic stellate cells become activated during the early stages of hepatic injury associated with fibrogenesis. The mannose 6-phosphate/insulin-like growth factor-II receptor (M6P/IGFIIR) plays an important role in early fibrogenesis by participating in the activation of latent transforming growth factor-beta, a potent inducer of the matrix proteins in activated stellate cells that define the fibrotic phenotype. In this study we examined hepatic stellate cell regulation of M6P/IGFIIR expression and found that M6P/IGFIIR mRNA transcript levels increased in stellate cells from rats exposed to carbon tetrachloride (CCl4), a potent fibrogenic stimulant. Two E-boxes residing in the proximal promoter of M6P/IGFIIR were found to each bind a novel 75-kDa transcription factor (P75) in quiescent stellate cells of normal livers. This E-box binding was down-regulated as an early response in stellate cells exposed to CCl4, coinciding with increased M6P/IGFIIR transcript levels. Mutagenized E-boxes in M6P/IGFIIR promoter-chloramphenicol acetyltransferase (CAT) reporter constructs produced a substantial increase in reporter expression when compared with the corresponding native promoter-CAT construct when transfected in culture-activated stellate cells, suggesting P75's role as a repressor. The results indicate P75's participation in the regulation of M6P/IGFIIR transcription in hepatic stellate cells during fibrogenesis.

Decreased PKC-alpha expression increases cellular proliferation, decreases differentiation, and enhances the transformed phenotype of CaCo-2 cells

Previous studies have shown that PKC-alpha protein expression is decreased in sporadic human colon cancers, as well as in colonic tumors of rats induced by chemical carcinogens. To elucidate the potential role of PKC-alpha on several phenotypic characteristics of colon cancer cells, we have transfected cDNAs for PKC-alpha in sense or antisense orientations into CaCo-2 cells, a human colonic adenocarcinoma cell line. Transfected clones were isolated that demonstrated approximately 3-fold increases (sense transfectants) and approximately 95% decreases (antisense transfectants) in PKC-alpha expression with no significant alterations in other PKC isoforms. Transfection of CaCo-2 cells with PKC-alpha in the antisense orientation resulted in enhanced proliferation and decreased differentiation, as well as in a more aggressive transformed phenotype compared with empty vector-transfected control cells. In contrast, cells transfected with PKC-alpha cDNA in the sense orientation demonstrated decreased proliferation, enhanced differentiation, and an attenuated tumor phenotype compared with these control cells. These data show that alterations in the expression of PKC-alpha induce changes in the proliferation, differentiation, and tumorigenicity of CaCo-2 cells. Furthermore, these findings indicate that loss of PKC-alpha expression in sporadic human and chemically induced colonic cancers may confer a relative growth advantage during colonic malignant transformation.

Glucose deprivation-induced cytotoxicity and alterations in mitogen-activated protein kinase activation are mediated by oxidative stress in multidrug-resistant human breast carcinoma cells

We previously observed that glucose deprivation induces cell death in multidrug-resistant human breast carcinoma cells (MCF-7/ADR). As a follow up we wished to test the hypothesis that metabolic oxidative stress was the causative process or at least the link between causative processes behind the cytotoxicity. In the studies described here, we demonstrate that mitogen-activated protein kinase (MAPK) was activated within 3 min of being in glucose-free medium and remained activated for 3 h. Glucose deprivation for 2-4 h also caused oxidative stress as evidenced by a 3-fold greater steady state concentration of oxidized glutathione and a 3-fold increase in pro-oxidant production. Glucose and glutamate treatment rapidly suppressed MAPK activation and rescued cells from cytotoxicity. Glutamate and the peroxide scavenger, pyruvate, rescued the cells from cell killing as well as suppressed pro-oxidant production. In addition the thiol antioxidant, N-acetyl-L-cysteine, rescued cells from glucose deprivation-induced cytotoxicity and suppressed MAPK activation. These results suggest that glucose deprivation-induced cytotoxicity and alterations in MAPK signal transduction are mediated by oxidative stress in MCF-7/ADR. These results also support the speculation that a common mechanism of glucose deprivation-induced cytotoxicity in mammalian cells may involve metabolic oxidative stress.

Gamma radiation induces CD69 expression on lymphocytes

Gamma radiation activates protooncogenes that are involved in early signal transduction, e.g., Raf-1. Most studies of effects of gamma radiation on lymphocytes deal with regulation of gene expression. However, early surface receptor expression in response to radiation has not been reported. We studied the effect of radiation on lymphocyte CD69 expression and BrdU uptake in the absence or presence of phytohemagglutinin (PHA). Radiation induces CD69 expression on T and B cells in a dose- and time-dependent manner. Four hours after a dose of 906 cGy, approximately 90% of B and 12% of T cells express CD69. CD69 expression diminishes after 6 h and requires de novo protein synthesis and protein phosphorylation. Radiation alone does not stimulate cell proliferation, as measured by BrdU incorporation, at any radiation dose tested. Furthermore, radiation enhances PHA induced CD69 expression at 2 h, but inhibits BrdU incorporation at day 3 in a dose-dependent fashion. CD69 functions as a marker for response to radiation, but unlike antigen or mitogen, radiation-induced CD69 expression does not lead to proliferation.

Increased phagocyte Fc gammaRI expression and improved Fc gamma-receptor-mediated phagocytosis after in vivo recombinant human interferon-gamma treatment of normal human subjects

Recombinant human interferon-gamma (rhIFN-gamma) decreases the frequency of serious infections in patients with chronic granulomatous disease (CGD) through an unknown mechanism. To test the hypothesis that it exerts a beneficial effect by enhancing clearance of microbes from the bloodstream and tissues, normal human subjects were treated in vivo with rhIFN-gamma. Phagocyte opsonic receptor expression, serum opsonin levels, and phagocytosis of bacteria were then measured. A 4.7-fold increase in neutrophil expression of the high-affinity Fc gamma-receptor (Fc gammaRI) was observed that peaked 48 hours after the initiation of rhIFN-gamma treatment (P < .05). Monocyte expression of Fc gammaRI, Fc gammaRII, Fc gammaRIII, CD11a, CD11b, CD18, and HLA-DR also significantly increased with peak expression at 48 hours. Phagocytosis by neutrophils of killed Staphylococcus aureus opsonized with heat-inactivated pooled human serum significantly improved after rhIFN-gamma treatment (P < .05) and correlated with Fc gammaRI expression by neutrophils (r = .8, P < .001). This increase in ingestion could be inhibited by anti-Fc gammaRI monoclonal antibodies. Levels of the serum opsonin lipopolysaccharide-binding protein also significantly increased after in vivo rhIFN-gamma (P < .05). These results suggest that the protective effect of rhIFN-gamma in patients with CGD may involve improved microbial clearance. Moreover, improved phagocyte trafficking may occur secondary to increased expression of monocyte beta2-integrins. Because these IFN-gamma-related improvements in host defense were seen in normal hosts, rhIFN-gamma may have broader applications in the treatment of various disorders of immunity in addition to its demonstrated efficacy in CGD.

Flow cytometric HLA-B27 typing using CD3 gating and molecules of equivalent soluble fluorochrome (MESF) quantitation

The determination of HLA-B27 (B27) status is important in the diagnosis of ankylosing spondylitis, Reiter's disease, and other arthropathies. Flow cytometric (FCM) typing of B27 is a relatively new method which allows for rapid turnaround time and low cost. However, different leukocyte populations may manifest significant variation in staining intensity with B27 antibodies. Therefore, gating utilizing only light scatter properties of cells may lead to high readings in some B27-negative samples. Fluorescence gating on CD3+ cells were postulated as a means to eliminate these anomalies. Furthermore, quantitative FCM measurements, as afforded through use of molecules of equivalent soluble fluorochrome (MESF) units, can minimize day-to-day and instrument-to-instrument variabilities in fluorescence measurements. We compared CD3 gating to light scatter gating and MESF analysis on 123 specimens in a 4-month period and found: 1) CD3 gating gave the lowest nonspecific B27 antibody binding among B27-negative subjects; 2) there was no significant difference in MESF values between CD3 gating and light scatter gating of B27-positive samples; 3) there was a wide range of B27 antibody binding fluorescence intensities among B27-positive subjects; 4) identification of patients with low B27 expression may require the use of CD3 gating in order to avoid costly confirmation testing; 5) fluorescent standard beads are stable for routine use in a clinical flow cytometry laboratory.

Suppression of stellate cell type I collagen gene expression involves AP-2 transmodulation of nuclear factor-1-dependent gene transcription

The regulation of collagen gene expression was studied in culture-activated rat hepatic stellate cells, the fibrogenic effector cell involved in hepatic fibrogenesis. Treatment of cells with a 5-lipoxygenase-specific inhibitor caused a reduction in alphaI(I) collagen mRNA transcript abundance, which suggested that leukotriene production was involved in maintaining the activated cell's high level of collagen mRNA production. The underlying mechanism involved a decrease in collagen gene transcription. Suppression of gene transcription was localized to an nuclear factor-1 (NF-1) binding domain in the proximal promoter and an AP-2 binding domain adjacent to it. Gel retardation assays demonstrated that an increase in AP-2 binding adjacent to the NF-1 site was likely to be the transmodulator responsible for the suppression of the NF-1-dependent gene expression. The data suggest that post-translational alterations in AP-2 activity are responsible for this unappreciated mechanism of regulating the collagen gene.

Bile acid stimulation of early growth response gene and mitogen-activated protein kinase is protein kinase C-dependent

Hepatic stellate cells are exposed to elevated bile acid levels during hepatic injury and fibrogenesis. Upon activation, the stellate cell becomes a major effector cell during the development of hepatic fibrosis and cirrhosis. Bile acids may function as costimulatory signalling molecules. This hypothesis was tested in vitro using rat-derived hepatic stellate cells. Bile acids were studied at concentrations that occur during cirrhosis in vivo. Conjugated and unconjugated bile acids rapidly induced egr and fos gene expression as well as cytoplasmic mitogen-activated protein kinase (MAPK) activation. Protein kinase C was required for both egr induction and MAPK activation. These studies imply that bile acids could contribute to the perpetuation of hepatic fibrosis by helping to keep the stellate cell in an activated state.

Hepatic fibrogenesis

Hepatic fibrogenesis may be the end result of chronic alcohol abuse, viral or parasitic infection, heavy metal overload, bile duct obstruction, or autoimmune disease. The sinusoidal hepatic stellate cell (or Ito cell or lipocyte) is the major effector cell that proliferates during fibrogenesis and produces abnormal amounts of extracellular matrix proteins as well as matrix-degrading enzymes. This article summarizes the known matrix proteins and the putative regulatory cytokines, cytoplasmic kinases, and transcription factors involved in this process.

Raf and mitogen-activated protein kinase regulate stellate cell collagen gene expression

Hepatic stellate cells become activated into myofibroblast-like cells during the early stages of hepatic injury associated with fibrogenesis. The subsequent dysregulation of hepatic stellate cell collagen gene expression is a central pathogenetic step during the development of cirrhosis. The cytoplasmic Raf and mitogen-activated protein (MAPK) kinases were found to differentially regulate alpha I(I) collagen gene expression in activated stellate cells. This suggests an unappreciated branch point exists between Raf and MAPK. A MAPK-stimulatory signal was mapped to the most proximal NF-1 and Sp-1 binding domains of the 5'-untranslated region of the collagen gene. A Raf-inhibitory signal was mapped to a further upstream binding domain involving a novel 60-kDa DNA-binding protein (p60). The cell-specific expression and induction of p60 in stellate cells during the early stages of hepatic fibrogenesis in vivo suggest a central role for this pathway during liver injury and stellate cell activation.

Adaptation to eccentric exercise: effect on CD64 and CD11b/CD18 expression

The primary purpose of the study was to examine circulating neutrophils and monocytes and their plasma membrane expression of CD64, CD11b, and CD18 after two bouts (B1 and B2) of eccentric exercise. Subjects (n = 10) performed 25 forced-lengthened contractions of the forearm flexors on two occasions separated by 3 wk. Blood samples were obtained before exercise and at 1.5, 6, 12, 24, 48, 72, and 96 h of recovery. CD64, CD11b, and CD18 expression was determined via direct immunofluorescence and used as an indicator of neutrophil and monocyte activation. Creatine kinase activity (B1 = 1,390, B2 = 108 U/l), myoglobin (B1 = 163, B2 = 41, ng/dl), and muscle soreness and tenderness were higher (P < 0.01) after B1 compared with B2. Neutrophils at 6, 12, and 96 h were higher (P < 0.05) for B1 vs. B2. CD11b expression on neutrophils was 2.7-fold higher at 72 h for B1 vs. B2. CD64 expression on neutrophils at 72 and 96 h was 1.4- and 1.9-fold higher, respectively, for B1 vs. B2. At 72 and 96 h, CD18 and CD64 expression on monocytes was 1.3-fold higher for B1 vs. B2. The observed changes were not significantly correlated with changes in creatine kinase activity or myoglobin. In conclusion, the adaptation to eccentric arm exercise was associated with a reduction in circulating neutrophils and a lower state of neutrophil and monocyte activation.

Flow cytometric reticulocyte maturity index: a useful laboratory parameter of erythropoietic activity in anemia

Flow cytometric reticulocyte analysis is superior to manual reticulocyte counting with respect to precision and sensitivity. Furthermore, because the fluorescence intensity of reticulocytes is directly proportional to the erythrocyte RNA content, flow cytometric analysis using thiazole orange gives a quantitative reticulocyte maturity index (RMI). Previous studies have demonstrated that the RMI parameter is the earliest indicator of bone marrow engraftment following transplantation. In the present study, we analyzed the correlation of the RMI to standard red cell parameters, reticulocyte percentage, and absolute reticulocyte count in 413 anemic patients. The correlation of RMI to serum erythropoietin (Epo) and serum transferrin receptor (TfR) was analyzed in a subset of anemic blood samples. We found weak correlations between the RMI and hemoglobin (r2 = 0.041), hematocrit (r2 = 0.038), reticulocyte percentage (r2 = 0.078), and absolute reticulocyte count (r2 = 0.087). Stronger correlations were observed between the RMI and Epo (r2 = 0.181) and the TfR (r2 = 0.191). The results indicate that the RMI represents a cost-effective measurement of erythropoietic activity and provides an additional parameter to classify anemic patients into categories of high and low erythropoietic activity, especially in hypoproductive anemias.

Lipoxygenase inhibitors block PDGF-induced mitogenesis: a MAPK-independent mechanism that blocks fos and egr

Hepatic Ito cells proliferate during liver injury and fibrogenesis. Platelet-derived growth factor (PDGF)-induced [3H]thymidine incorporation was studied as Ito cells express the PDGF receptor after injury and activation. Pretreatment with either the nonspecific lipoxygenase inhibitor (nordihydroguaiaretic acid) or specific inhibitors of 5-lipoxygenase (SC-41661 and ICI-230487) inhibited PDGF-induced mitogenesis. Ito cells predominantly produce the leukotriene (LT) C4 >> LTB4. The PDGF-induced signal transduction cascade was studied to determine the potential mechanism of action of the lipoxygenase inhibitors. It was found that PDGF receptor abundance and receptor activation were not altered by lipoxygenase inhibition, suggesting that a postreceptor mechanism was involved. The two-key cytoplasmic serine-threonine kinases Raf and MAPK (mitogen-activated protein kinase), which are induced by PDGF and transmit the signal to the nucleus, were also not altered. Because Raf and MAPK can independently induce nuclear signaling, this suggests that the mechanism of action lies parallel or distal to these secondary messengers. Lipoxygenase inhibition did result in the suppression of PDGF-induced fos and egr expression. Collectively, this work suggests that lipoxygenase inhibition leads to the suppression of mitogenesis in part by disrupting the nuclear signaling that is required for protooncogene transcription at a step distal or parallel to MAPK activation.

Exercise-induced muscle damage: effect on circulating leukocyte and lymphocyte subsets

The purpose of this study was to determine the effect of downhill and level running on circulating leukocyte and lymphocyte subsets and T lymphocyte activation. Using a random cross-over design, 10 runners completed two trials of 60 min of level running (0% grade; LR) and downhill running (-10% grade; DHR) at 70% of level VO2max. Blood samples were obtained preexercise and immediately postexercise (POST) and at 1.5, 12, 24, and 48 h of recovery. Creatine kinase activity peaked at 12 h of recovery from DHR and was not significantly altered following LR. The number of total T, CD16+, CD3+CD56+ cells were significantly higher POST DHR compared with LR. Leukocyte and neutrophil counts were significantly higher at 1.5 and 12 h of recovery from DHR compared with LR. The number of activated CD8+ cells (CD25+ CD8+) was significantly higher at 12 h of DHR compared to LR. Total T cells were significantly reduced at various time points during the 48 h of recovery from LR and DHR. In summary, DHR relative to LR resulted in a greater mobilization of lymphocytes (post), neutrophils (1.5-12 h of recovery) and activation of CD8+ cells at 12 h of recovery. In addition, reductions in circulating T lymphocyte subsets occurred following both conditions.

Protein kinase C and mitogen-activated protein kinase are required for 1,25-dihydroxyvitamin D3-stimulated Egr induction

Recent studies have demonstrated that 1,25-dihydroxyvitamin D3 (D3) can activate Raf kinase and induce Egr expression in cultured rat hepatic Ito cells (Lissoos, T. W., Beno, D. W. A., and Davis, B. H. (1993) J. Biol. Chem. 268, 25132-25138). Since Raf is an upstream activator of mitogen-activated protein kinase (MAPK), the current study evaluated the ability of D3 to activate MAPK. D3-activated MAPK and induced its cytoplasmic to perinuclear translocation in Ito cells. MAPK activation was found to be protein kinase C-dependent, which was analogous to previous studies of D3 and Raf activation. To further explore the D3 cascade, a series of transient transfections were performed using dominant negative raf and MAPK mutant plasmids which effectively block Ras-induced Raf and MAPK activity, respectively. D3 induced a marked increase in the expression of a chloramphenicol acetyltransferase reporter gene linked to the Egr promoter (egr-CAT). When the dominant negative Raf plasmid was co-transfected, there was no significant reduction in egr-CAT. In contrast, when the dominant negative MAPK plasmid was co-transfected, egr-CAT induction was completely abolished. These results suggest that 1) D3 stimulates MAPK via a protein kinase C-dependent pathway, 2) D3-induced Egr expression can occur via a pathway independent of Ras-induced Raf, and 3) D3 absolutely requires MAPK activity for Egr expression.

Flow cytometric reticulocyte analysis. Multiinstitutional interlaboratory correlation study

Reticulocyte analysis by flow cytometry offers precision and sensitivity greater than those of conventional morphologic methods and permits derivation of a reticulocyte maturity index. However, interlaboratory variability has not yet been reported. The authors analyzed 310 samples at eight sites using 11 instruments over a 4-month period to examine intermethod and interlaboratory variabilities. Stains included thiazole orange, ethidium bromide, and auramine O. Instruments included models by Coulter, Becton Dickinson, TOA Medical Electronics, and Ortho Diagnostics. The coefficient of variation (CV) among all sites and methods on these samples varied as a function of the reticulocyte percentage, ranging from a mean CV of 69% for samples with < .5% reticulocytes to 24.1% for those with > 2.5% reticulocytes. The best performance was observed with the TOA R-1000 dedicated reticulocyte analyzers, with a mean CV of 18.4% for samples with < .5% reticulocytes and 4.6% for samples with > 2.5% reticulocytes. The reticulocyte maturity index showed comparable intersite precision, with a mean CV of 16% for samples with > 2.5% reticulocytes with multipurpose flow cytometers and a mean CV of 7.3% with the TOA R-1000 instruments. Interclass correlations among all sites ranged from .79 to .99 for the reticulocyte counts and .41 to .88 for the reticulocyte maturity index. The authors conclude that flow cytometric reticulocyte analysis is more precise than manual reticulocyte analysis. With greater automation of this methodology, further interlaboratory standardization of reticulocyte counts and the reticulocyte maturity index can be achieved.

Automated reticulocyte analysis. Clinical practice and associated new parameters

Automated reticulocyte analysis, through continued instrument, software, and reagent developments, provides improved precision for the reticulocyte count. This rapid and simple testing assists in providing a cost effective and sensitive approach to the diagnosis and therapeutic monitoring of the anemic patient. As laboratory and clinical hematologist become familiar with the benefits and expanding clinical applications of this technology, the use of reticulocyte analysis will increase.

Prostaglandin E suppression of platelet-derived-growth-factor-induced Ito cell mitogenesis occurs independent of raf perinuclear translocation and nuclear proto-oncogene expression

Ito cell mitogenesis occurs during liver injury and fibrogenesis in vivo coincident with the de novo expression of Ito cell PDGF beta receptor messenger RNA. PDGF-induced mitogenesis was studied in cultured rat hepatic Ito cells which resemble the myofibroblast associated with liver injury. Pretreatment with prostaglandin E markedly suppressed the PDGF response in a dose-dependent fashion. The PDGF-induced cascade was studied with or without PGE to determine the level of regulation which induced the observed suppression. PGE caused no apparent diminution in the abundance of the surface PDGF beta receptor nor its subsequent activation and tyrosine phosphorylation following PDGF stimulation. The cytoplasmic 'secondary messengers' mitogen-activated protein kinase pp42-44 and raf kinase, appeared to be comparably induced and therefore unaffected by PGE. Raf perinuclear translocation was also intact and comparable degrees of nuclear egr, fos, and jun expression occurred. Since other studies have suggested that many of these features of the PDGF cascade may be causally and sequentially linked, the data collectively suggests that the dominant PGE mitogenic suppressive effect resides at a raf-MAP parallel pathway or at a nuclear level distal to the induction of these early growth response genes.

1,25-Dihydroxyvitamin D3 activates Raf kinase and Raf perinuclear translocation via a protein kinase C-dependent pathway

1,25-Dihydroxyvitamin D3's (D3) potential mitogenic mechanism of action was pursued in cultured rat hepatic Ito cells, a fibrogenic effector cell which proliferates in vivo during liver injury and fibrogenesis. D3 stimulated Ito cell DNA synthesis and potentiated platelet-derived growth factor-induced mitogenesis. D3's enhancement of [3H]thymidine incorporation was associated with nuclear Egr expression. Recent studies have causally linked the activated proto-oncogene c-Raf with downstream Egr induction. The serine-threonine kinase Raf protein is phosphorylation-activated by a large array of agonists including plasma membrane and cytoplasmic tyrosine kinases but has not previously been associated with the steroid superfamily of mediators. To consider potential prenuclear acute pathways of D3-induced stimulation, the activation of Raf was examined following D3 exposure. D3 induced Raf activation as assessed via (a) enhanced Raf phosphorylation following in vivo 32P labeling, (b) enhanced kinase function utilizing exogenous histone 1 protein as substrate, and (c) the shift in Raf physical localization changing from a diffuse cytoplasmic distribution to a perinuclear domain. A similar activation of Raf kinase was found in 3T3 cells exposed to D3 with enhanced histone phosphorylation detectable within 1 min following stimulation. The proximal cascade leading to Raf kinase activation may involve a protein kinase activity was severely attenuated by stimulated kinase activity was severely attenuated by previous phorbol ester treatment for 20 h or staurosporine pretreatment.

Gamma-linolenic acid suppression of hepatic Ito cell mitogenesis: post-PDGF receptor prostaglandin-independent mechanism

Ito cell mitogenesis occurs during liver injury and fibrogenesis in vivo. Platelet-derived-growth factor (PDGF)-induced mitogenesis was studied in cultured rat hepatic Ito cells, which resemble the myofibroblast associated with liver injury. Pretreatment with gamma-linolenic acid (GLA), an essential fatty acid prostanoid precursor, markedly suppressed the PDGF response in a dose-dependent reversible fashion. Prostaglandins E1 and E2 were found to be the predominant prostanoids formed by cultured Ito cells. GLA depressed endogenous PG production, suggesting that the antimitogenic effect was independent of GLA conversion to a prostanoid metabolite. The PDGF-induced cascade was studied with and without GLA to determine the level of regulation that induced the observed suppression. GLA caused no apparent diminution in the abundance of the surface PDGF-beta receptor nor its subsequent activation and tyrosine phosphorylation after PDGF stimulation. Raf kinase activation and Raf perinuclear translocation were also intact despite the presence of GLA. PDGF induction of nuclear Egr and Fos also occurred with or without GLA. Activation of the serine threonine kinase c-Raf has previously been found to be sufficient to activate egr and fos and to induce mitogenesis. Therefore, the GLA suppressive effect is likely to be operative at a parallel non-Raf pathway or distal to Raf-induced early gene expression.

Retinoic acid suppresses the response to platelet-derived growth factor in human hepatic Ito-cell-like myofibroblasts: a post-receptor mechanism independent of raf/fos/jun/egr activation

Activated Ito-cell-like myofibroblasts proliferate in vivo during human liver injury and subsequent fibrogenesis. To examine the associated regulatory mechanisms, human liver myofibroblasts were characterized after culture purification from mixed liver-cell isolates obtained from perfused normal human livers. The cells resembled rat Ito-cell-derived myofibroblasts expressing desmin and alpha-smooth-muscle actin filaments as well as the interstitial collagens type I and III. [3H]Thymidine incorporation was inducible with platelet-derived growth factor (PDGF) and was suppressible with retinoic acid (RAc) in a concentration-dependent fashion. RAc suppression did not alter PDGF alpha- or beta-receptor abundance or activation. In addition, RAc functioned via a pathway distal or independent of cytoplasmic raf activation (i.e. phosphorylation, kinase function and perinuclear translocation) and nuclear fos, jun and egr expression, as these steps were similarly unaffected by RAc treatment. Since normal Ito cells contain abundant amounts of vitamin A which is lost during activation, these data suggest that retinoids could contribute to the maintenance of the quiescent non-proliferative state by suppressing mitogenesis at a post-cytokine receptor step distal from or independent of fos/jun/egr [e.g. via changes in activator protein-1 (AP-1) binding].

Posttranslational inhibition of Ito cell type I collagen production by triiodothyronine

Increased Ito cell collagen production occurs during in vivo liver fibrogenesis. Regulation of the overproduction of collagen was studied in cultured rat hepatic Ito cells, which resemble the myofibroblast associated with liver fibrosis. Previous studies suggest that the steroid hormones, retinoic acid, and glucocorticoids may have antifibrogenic properties in vitro and in vivo when used at pharmacological doses. Their potential roles at physiological levels are not well understood. The current study examined the potential regulation of the overproduction of type I collagen in cultured rat hepatic Ito cells by another steroid hormone, 3,5,3'-triiodo-L-thyronine (T3). T3 induced a 3.4-fold reduction in type I collagen production. The effect was dose dependent and was maximal with physiological levels of T3 (10(-9) M). The effect of T3 was independent of any suppression in total protein synthesis. The mechanism of the suppressive effect of T3 on collagen production was explored and was found to be at a posttranslational level. This study suggests that the inhibitory effects of T3 on type I collagen production are likely caused by enhanced intracellular turnover of type I collagen.

Administration of prostaglandin E1 analog reduces rat hepatic and Ito cell collagen gene expression and collagen accumulation after bile duct ligation injury

Recent studies suggest that prostaglandin E may have the ability to suppress cytokine responsiveness. We examined the effects of prostaglandin E administration on several parameters of acute and chronic liver injury induced by bile duct ligation. Enisoprost, a prostaglandin E1 analog, was found to suppress early hepatic and Ito cell type I collagen gene expression without diminishing the induction of the fibrogenic cytokine transforming growth factor-beta. Overall liver inflammation and cell proliferation were not altered, suggesting that prostaglandin E acts distal to the initial injurious event(s). During later phases, drug administration reduced total collagen accumulation and type I collagen periductular infiltration associated with early nodule formation.

Flow cytometric reticulocyte analysis and the reticulocyte maturity index

Reticulocyte analysis has evolved to one of the accepted and routinely practiced clinical applications of flow cytometry technology. Similar to CD4 measurements, FCM technology has contributed to documented improvements in reticulocyte counting precision over previous microscope-based techniques. The ability to FCM instruments to quantitate fluorescence intensity has been utilized to derive a parameter of reticulocyte maturity, which we have termed the reticulocyte maturity index. The FCM-derived RMI parameter offers an additional perspective to assess the erythropoietic response in anemic patients over reticulocyte counting alone and provides further insight into the differential diagnosis of anemia. Clinical utility of the RMI has been reported in monitoring expensive, new-technology therapies, such as bone marrow transplantation and erythropoietin therapy. FCM reticulocyte analysis is still not fully mature, but is in a state of continued evolution. Needs exist for (i) improved software for data analysis, (ii) newer automation techniques to improve interlaboratory correlations, and (iii) further validation and refinement of the reticulocyte maturity index parameter.

Proposal for standardization of flow cytometric reticulocyte maturity index (RMI) measurements

Flow cytometric (FCM) reticulocyte analysis is more accurate, sensitive, and reproducible relative to previously employed manual microscopic methods in clinical laboratory hematology. FCM reticulocyte analysis using RNA binding fluorochromes additionally allows for the quantification of fluorescence intensity or population distribution of the reticulocyte RNA content. Viewed from the perspective of erythroid maturation, quantification of the fluorescence intensity distribution provides a reticulocyte maturation index (RMI). We performed a systematic study of 18 different methods to express thiazole orange stained reticulocyte fluorescence intensity, compared to standard mean fluorescence intensity quantification, using 185 anemic and non-anemic human blood samples. The method best correlating with the mean fluorescence intensity RMI on 2 different FCM instruments (R2 = 0.93 and 0.86) was a ratio of the highly fluorescent reticulocytes, defined using a normal adult population, and the total number of reticulocytes (HFR%). In contrast to mean fluorescence intensity measurements, a HFR% RMI parameter can provide similar units of expression (0.01-1.00) with good correlation between different FCM instruments (R2 = 0.76). We conclude the HFR% method of RMI expression provides a superior means of interlaboratory standardization and clinical comprehension of this useful diagnostic parameter in clinical laboratory hematology.

Roles of the Tn21 merT, merP, and merC gene products in mercury resistance and mercury binding

The mercury resistance (mer) operon of the gram-negative transposon Tn21 encodes not only a mercuric reductase and regulatory genes but also two inner membrane proteins (MerT and MerC) and a periplasmic protein (MerP). Although the merT, merP, and merC genes have been implicated in Hg(II) transport, the individual roles of these genes have not been established. We created in vitro precise deletion and frameshift mutations that eliminated each of the genes singly and in combination. Our results show that both merT and merP are required for Hg(II) binding but that merC is not. Both merT and merP are required for full expression of Hg(II) resistance, but loss of merP is less deleterious than loss of merT. Furthermore, mutations eliminating both merT and merP decrease resistance more than the single mutations do. In contrast, mutating merC had no effect on Hg(II) resistance. Both the merT and merP mutations increase the threshold Hg(II) concentration for induction of merA-lacZ transcriptional fusions and cause an increase in the maximal expression level. In contrast, the merC mutation had little effect on the threshold inducing concentration of Hg(II) but decreased the level of expression. Our results show that merT and merP alone are sufficient to specify a mercury transport system. The role of merC remains obscure.

Pathogenesis of hepatic fibrosis and the role of cytokines

No definitive therapy exists for the treatment of hepatic fibrosis and cirrhosis. Recent evidence suggests that hepatic lipocytes (Ito cells, fat storage cells, or stellate cells of the liver) are responsible for much of the collagen hypersecretion and nodule formation that occurs during hepatic fibrosis and cirrhosis. This review describes the cellular mechanisms of hepatic fibrogenesis emphasizing new experimental data about cytokines or growth factors to suggest potential avenues of future therapeutic design.

Retinoic acid and transforming growth factor beta differentially inhibit platelet-derived-growth-factor-induced Ito-cell activation

Sinusoidal Ito cells (stellate or fat-storing cells) undergo excessive cellular proliferation before the establishment and progression of hepatic fibrosis and cirrhosis. Retinoic acid and transforming growth factor beta (TGF beta) both inhibit Ito-cell [3H]thymidine incorporation in serum-containing media. Serum-induced mitogenicity was dependent on platelet-derived growth factor (PDGF). Additionally, pre-treatment of Ito cells with retinoic acid and TGF beta blocked PDGF-induced cell proliferation. TGF beta, but not retinoic acid, diminished PDGF-receptor and smooth-muscle alpha-actin abundance.

Isodicentric chromosome 18q as sole abnormality in a histologically normal bone marrow from a patient with diffuse large-cell non-Hodgkin's lymphoma

Cytogenetic analysis was performed on the histologically and immunophenotypically normal bone marrow (BM) of a 33-year-old woman with non-Hodgkin's lymphoma (NHL) before BM harvest. Unstimulated 24- and 48-hour cultures produced only normal metaphases. A pokeweed mitogen (PWM)-stimulated 48-hour culture, however, showed a clonal isodicentric chromosome 18q as the sole abnormality, suggesting a role for this approach in detection of submicroscopic BM involvement by B-cell NHL.

Flow cytometric DNA content analysis in neuroendocrine carcinoma of the lung. Correlation with survival and histologic subtype

The DNA content of 53 primary and locally metastatic pulmonary neuroendocrine carcinomas was retrospectively determined by flow cytometric analysis of nuclei released from paraffin-embedded tissues and compared with histologic subtypes and clinical survival. Forty-one percent (9 of 22) of tumors classified as well-differentiated neuroendocrine carcinoma (WDNC) were aneuploid. In contrast, 85% (17 of 20) of small cell neuroendocrine carcinoma (SCNC), and 73% (8 of 11) of intermediate cell neuroendocrine carcinoma (ICNC) were aneuploid. DNA content was not a significant independent predictor of patient survival within each histologic subtype (P greater than 0.05 for all subtypes). Yet, when all cases were examined as a single group, diploid cases showed better clinical survival than cases with DNA aneuploidy (P less than 0.02). However, the survival advantage for diploid DNA content did not quite achieve statistical significance when only cases of limited stage disease were analyzed (0.10 greater than P greater than 0.05). Histologic subtype was also a prognostic indicator, with WDNC cases showing a significantly longer survival than either SCNC (P less than 0.05) or ICNC (P less than 0.02), for those cases with limited-stage disease. These results indicate information on clinical staging and the histologic subtype are important parameters to compare with DNA content analysis in determining independent prognostic factors in neuroendocrine or small cell carcinoma of the lung.

A morphological and phenotypic analysis of Walker 256 cells

A detailed morphological analysis of Walker 256 cells sensitive and resistant to cis-diamminedichloroplatinum(II) has been performed. Two cell populations are identified by electron microscopy of differing differentiation corresponding structurally to cells reported in experimentally induced metastases. Phenotyping of the cells using a number of monoclonal antibodies by immunocytochemistry and flow cytometry showed the absence of epithelial cell markers: however, the cells stained intensely for markers for germ and/or hematopoietic cells. Further studies utilizing monoclonal antibodies to lymphoid, myeloid, and monocytoid cells showed the cells to be monocytoid in origin. No evidence of cell heterogeneity was evident from the phenotypic experiments (a biphasic pattern was not observed). Enzyme histochemistry showed strong focal acid phosphatase activity suggestive of cells of hematopoietic origin. Thus the concept that these cells reflect an epithelial cell of origin is not substantiated by phenotyping with two methodologies.

Neutrophil activation through high-affinity Fc gamma receptor using a monomeric antibody with unique properties

The high-affinity, type I Ig Fc receptor (Fc gamma RI) for human IgG1, human IgG3, murine IgG2a, and murine IgG3 is highly expressed on monocytes, neutrophils (PMN) in certain disease states, and phagocytes treated with interferon-gamma (IFN-gamma). We studied the activation of the human PMN oxidative burst and stimulated fluid pinocytosis induced by three monoclonal antibodies (MoAbs) directed against Fc gamma RI (CD64) to study the role of this receptor in Fc-mediated cellular activation. All three MoAbs were capable of triggering PMN activation from IFN-gamma-treated PMN when cross-linked with goat antimurine Ig reagents. However, MoAb 197 alone demonstrated a concentration-dependent activation of the oxidative burst without the use of a second cross-linking antibody. The oxidative burst and stimulated fluid pinocytosis responses induced by monomeric MoAb 197 could be elicited only after the IFN-gamma induction of approximately 8,000 Fc gamma RI receptor equivalents and did not occur in freshly isolated or control-cultured PMN. Competitive blocking of Fc binding of MoAb 197 by human IgG or purified Fc fragments inhibited cellular activation. We believe the ability of MoAb 197 to activate these oxidative burst and fluid pinocytic responses was because of its murine IgG2a subclass, which allowed it to function as a trivalent anti-Fc gamma RI antibody binding through the combination of its two FAB regions and the Fc domain. This study demonstrates that the cross-linking of CD64 can activate PMN oxidative and endocytic responses and supports a role for Fc gamma RI in the human neutrophil inflammatory response.

Retinoic acid modulates rat Ito cell proliferation, collagen, and transforming growth factor beta production

Recent studies suggest that vitamin A plays an inhibitory role with respect to "activation" of the hepatic Ito cell, a likely effector of hepatic fibrogenesis. Ito cell "activation" during fibrogenesis is characterized by a decrease in intracellular vitamin A and an increase in cellular proliferation and collagen production. To explore the hypothesis that retinoids have the capacity to diminish Ito cell activation, cultured Ito cells were exposed to retinoic acid and its effects assessed on three key features: cell proliferation, collagen protein production and mRNA abundance, and transforming growth factor beta protein production. Retinoic acid was 100-1,000X more potent than retinol with respect to inhibition of Ito cell proliferation. Interstitial collagen and transforming growth factor beta production were also reduced by 10(-6) M retinoic acid. The relative abundance of type I collagen mRNA however, was not significantly altered. By contrast, retinoic acid administration to rats caused a marked reduction in the abundance of type I collagen mRNA in both total hepatic and purified Ito cell RNA. The relative abundance of rat hepatic fibronectin or apolipoprotein E mRNA was not significantly altered. These studies demonstrate that retinoic acid can differentially modulate several key features of hepatic fibrogenesis in vitro and in vivo.

Autologous bone marrow transplantation for acute myeloid leukemia using monoclonal antibody-purged bone marrow

We report our experience from a clinical trial of autologous bone marrow transplantation (ABMT) in the treatment of 30 patients with acute myeloid leukemia (AML) using monoclonal antibody (MoAb) and complement-treated bone marrow. All patients were in complete remission (CR) at the time of transplant: 6 patients were in first CR, 18 in second CR, and 6 in third CR. The median age of all patients was 42 years (range 11 to 57 years). For marrow ablation, 28 patients were treated with cyclophosphamide and total body irradiation. One patient was treated with busulfan and cyclophosphamide and one was treated with busulfan and VP-16. Each patient was then transfused with autologous bone marrow that had been harvested previously and treated with two MoAbs, PM-81 and AML-2-23, and rabbit complement. Median time to recovery of neutrophils (500/microL) was 30 days, and platelets (20,000/microL) was 45 days. Median time for initial erythrocyte engraftment, assessed by a flow cytometric reticulocyte assay, was 13 days. Median overall and relapse-free survival of first CR patients was at least 17.4 months post-ABMT and the 2- and 3-year actuarial overall and relapse-free survival was 67% (+/- 19%). Median survival for the 24 patients in second or third CR was 6.8 months post-ABMT and 9.3 months since CR; however, six patients survived disease-free from 16 to 61 months post-ABMT. For the second and third CR group it was observed that six patients (5 of the 6 survivors) showed "inversions," when their post-ABMT remission lasted longer than any previous one. Actuarial 2- and 3-year disease-free and overall survival of patients in second and third CR was 25% (+/- 9%) and 18% (+/- 9%), and 29% (+/- 9%) and 23% (+/- 9%), respectively. ABMT avoids the problems of graft-versus-host disease and of finding suitable donors for allogeneic marrow transplantation.

A rapid redistribution of the transferrin receptor to the cell surface of HL-60 cells and K562 cells upon treatment with dimethyl sulfoxide due to slowing of endocytosis

Treatment of two human leukemia cell lines with 1.25% dimethyl sulfoxide at 37 degrees C results in a rapid increase in the number of transferrin receptors on the cell surface detected by fluorescein-labeled anti-transferrin receptor antibodies. Both HL-60 cells, a human myeloid cell line, and K562 cells, a human erythroid-myeloid cell line, showed a 25-65% increase in cell surface transferrin binding in parallel experiments. Scatchard plot analysis of the data indicates that the number of receptors increases while the affinity of transferrin for the receptor remains the same. This rapid increase in the number of receptors at the cell surface appears to be due to a slowing of endocytosis rather than an increase in externalization of the receptor.

Clinical flow cytometric reticulocyte analysis

The flow cytometric (FCM) analysis of reticulocytes in a clinical laboratory can be accomplished using acridine orange (AO), thiazole orange (TO), auramine O, thioflavin T, pyronin Y, dimethyl-oxacarbocyanine or transferrin receptor assays. AO and TO are vital stains, show good correlation with microscopic reticulocyte determinations and, when compared to each other, give an excellent correlation. The coefficient of variation is below 5% and batch analysis on blood samples stored for 96 h further reduces manpower needs. Finally we have used the mean fluorescent intensity of TO as a reticulocyte maturity index (RMI). In bone marrow transplant patients, the RMI has been the earliest indicator of marrow engraphment. Using the RMI we have been able to define three patterns of engraphment: early, delayed and failed. Although a variety of standards will be required, the clinical FCM reticulocyte analysis promises to be the preferred and accepted method in the clinical laboratory.

Utility of flow cytometric reticulocyte quantification as a predictor of engraftment in autologous bone marrow transplantation

Flow cytometric reticulocyte quantification with thiazole orange (TO) was used to study erythropoiesis in 20 patients following autologous bone marrow transplantation for the treatment of acute myelogenous leukemia. Flow cytometric reticulocyte analysis provided not only the reticulocyte percentage and absolute reticulocyte count but a quantitative reticulocyte maturity index (RMI) proportional to the amount of RNA in the reticulocytes. The RMI values, but not the reticulocyte percentage or absolute counts, correlated temporally with the rise in the absolute neutrophil counts in the posttransplantation period. In the majority of patients (12/20), the RMI value was the earliest indicator of bone marrow engraftment. The findings of this study demonstrate an important clinical utility of TO reticulocyte analysis by flow cytometry and indicate the diagnostic importance of the RMI measurement in the evaluation of erythropoietic activity in bone marrow transplant patients.

Flow cytometric reticulocyte quantification using thiazole orange provides clinically useful reticulocyte maturity index

Flow cytometric reticulocyte quantification with thiazole orange has been reported to be of potential utility in a clinical hematology laboratory. We have instituted this technique into routine clinical testing for 18 months and we describe this experience. Flow cytometric analysis provided not only reproducible, cost-effective reticulocyte quantification, but a quantitative reticulocyte maturity index proportional to the amount of RNA in the reticulocytes. The reticulocyte maturity index measurement represents an independent parameter of erythropoiesis, which provided clinically valuable information regarding bone marrow engraftment in patients following autologous bone marrow transplantation. The findings of this study demonstrate the clinical utility of thiazole orange reticulocyte analysis and indicate the diagnostic importance of the reticulocyte maturity index measurement in the evaluation of erythropoietic activity.

Continuous infusion of complement by an automated cell processor enhances cytotoxicity of monoclonal antibody sensitized leukemia cells

We report the use of the Haemonetics cell processor for monoclonal antibody (MoAb) and complement (C')-mediated lysis of leukemia cells. Using the HL-60 promyelocytic leukemia cell line, we can achieve a six-log depletion of HL-60 colony-forming cells in cell mixtures containing 1% HL-60 cells and 99% normal peripheral blood or bone marrow leukocytes at 10(7)/ml after a single 60-min treatment with an anti-myeloid MoAb, PM-81, plus C'. In this procedure, we continuously infuse a solution of fresh C' while removing medium containing spent C'. We have utilized this procedure to purge remission bone marrow from patients with acute myelogenous leukemia in preparation for autologous bone marrow transplantation. There were no adverse effects to normal progenitor cells of the granulocyte, monocyte and erythrocyte lineages as measured in colony-forming assays. Other potential benefits of using the cell processor method of cytotoxicity include reduction in treatment time and the amounts of costly reagents.