Topoisomerase II expression in normal haemopoietic cells and chronic lymphocytic leukaemia: drug sensitivity or resistance?

Chronic lymphocytic leukaemia (CLL) is a progressive disease, commonly treated in its early stage with alkylating agents. A multi-agent regimen which includes anthracyclines is used to treat advanced disease. Despite chemotherapy, the disease remains incurable. There is now considerable evidence to suggest that anthracyclines exert their effect via the nuclear enzyme topoisomerase II and that alterations in amount or activity of this enzyme may mediate drug resistance. We have investigated topoisomerase II mRNA expression in 34 CLL patients and in haemopoietic cells from 10 normal donors. Expression was found to be low but detectable in all patients and normals. Such low levels may contribute to the toxicity of alkylating agents, but could severely limit the effect of anthracyclines.

Human cytomegalovirus (HCMV) late-mRNA detection in peripheral blood of AIDS patients: diagnostic value for HCMV disease compared with those of viral culture and HCMV DNA detection

A reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect a human cytomegalovirus (HCMV) late mRNA in peripheral blood leukocytes (PBL) of 102 human immunodeficiency virus-infected individuals. The clinical value of this new technique for the diagnosis of acute HCMV disease was evaluated in comparison with viral culture and direct amplification of viral DNA (PCR). The sensitivity of the RT-PCR was slightly lower than that of the two other methods, but its specificity was 94%, compared to 55 and 32% for culture and PCR, respectively. Transcription of this late mRNA is linked to viral replication, and its detection in PBL confirms that these cells can support a complete viral cycle. The relationship between complete replicative cycles and HCMV disease makes RT-PCR a useful clinical tool.

Poly (adenosine diphosphate-ribose) synthesis in the anterior pituitary of the female rat throughout the estrous cycle: study of possible relation to cell proliferation and prolactin gene expression

To investigate whether cell proliferation and PRL gene expression in female rat pituitary during estrous cycle were mediated by the poly (ADP)-ribosylation of chromatin proteins, anterior pituitaries at different estrous cycle were obtained from female Wistar rats, and poly (ADP-ribose) synthesis, DNA synthesis, PRL and GH messenger RNAs and PRL content in the pituitary, and serum concentrations of PRL and estradiol were analyzed. From diestrus to proestrus, poly (ADP-ribose) synthesis, the contents of PRL messenger RNA and PRL in the pituitary increased significantly, and decreased at estrus. However, DNA synthesis and serum concentration of PRL showed a significant increase from proestrus to estrus. Serum estradiol concentration increased from diestrus to proestrus. No significant change was observed in the pituitary GH messenger RNA content during estrous cycle. The increase of PRL messenger RNA from diestrus to proestrus was abolished completely by the administration of nicotinamide, an inhibitor of poly (ADP-ribose) synthesis, to rats at diestrus. These results indicate that poly (ADP)-ribosylation of chromatin proteins may play some role in cell proliferation and transcription of PRL gene during rat estrous cycle.

Immunoactivation enhances the concentration of luteinizing hormone-releasing hormone peptide and its gene expression in human peripheral T-lymphocytes

An immunomodulatory role for LHRH was suggested when we reported the presence of immunoactive and bioactive LHRH and its mRNA in rat splenic and thymic lymphocytes. In this paper we report that human peripheral T-cells as well as its subsets CD4+ and CD8+ contained immunoactive and bioactive LHRH. Furthermore, analysis of phytohemagglutinin (PHA)-activated T-cell lysates for LHRH by RIA demonstrated that the mean concentration of LHRH in PHA-activated T-cells increased from 45 +/- 4.5 to 64 +/- 7 pg/10(6) cells after 24 h of culture and from 47 +/- 3.6 to 117 +/- 11.8 pg/10(6) cells (P < 0.01) after 48 h. While the LHRH concentration in PHA-activated cells increased over the last 24 h of culture h from 64 +/- 7 to 117 +/- 11.8 pg/10(6) cells (P < 0.001), there was no change in mean concentration of LHRH in T-cells kept in medium alone. In a preliminary study we found that fresh T-cells contain 20 +/- 1.4 pg pro-LHRH/10(6) cells, and PHA stimulation increased the pro-LHRH content similar to the increase in LHRH. As with unfractionated T-cells, a significant PHA-induced time-dependent enhancement of intracellular LHRH was noted in CD4+ and CD8+ T-cells. RNA extracted from lymphocytes was subjected to reverse transcription-polymerase chain reaction analysis using LHRH and histone-3.3, primers, the latter as an internal control. The polymerase chain reaction-generated data demonstrated that the relative amount of LHRH mRNA in cultured, but non-PHA-stimulated (resting), cells diminished dramatically between 5-24 h, but recovered by 48 h of culture. The relative amount of LHRH mRNA in PHA-stimulated cells revealed a markedly different pattern. LHRH message expression in PHA-activated cells increased slightly at 5 h of culture and was maximally stimulated by 24 h, but declined by 48 h of culture. The PHA activation-induced time-dependent enhancement of intracellular accumulation of LHRH peptide at 5 and 24 h was accompanied by increased LHRH message. However, the increased concentration of LHRH peptide at 48 h coincided with decreased LHRH message expression. The data from total protein synthesis in PHA-activated cells showed a progressive increase in protein synthesis, a pattern entirely similar to the changes in the cell content of LHRH.(ABSTRACT TRUNCATED AT 400 WORDS)

Molecular diversity of calpastatin in human erythroid cells

According to differences in mobility on SDS-polyacrylamide gel electrophoresis, calpastatins (inhibitor proteins of the calcium-dependent proteinase calpain) are classified into the tissue type (100-120 kDa) and the erythrocyte type (70 kDa), which lacks the amino-terminal domains (domains L and 1). We investigated the molecular diversity of calpastatin in human hematopoietic cells by Western-blot analysis and by the reverse-transcription-polymerase-chain reaction method. While the mononuclear and polymorphonuclear cells in peripheral blood showed the tissue type (110 and 114 kDa), a cell line of erythroid cells (JK-1) showed both the tissue type (110 kDa) and the erythrocyte type (70 kDa) at approximately equal ratios. When the lysate of JK-1 cells was incubated in the presence of ATP, the 110-kDa form was degraded much faster than the 70-kDa form. In human erythrocytes, the 110-kDa form was identified as the tissue type by an antibody recognizing domain L, and this form was also present in addition to the predominant 70-kDA form. JK-1 cells, as well as nucleated cells in peripheral blood, contained calpastatin mRNA with exon-3-deleted. Glioblastoma and fibroblast cell lines expressed the nondeleted calpastatin mRNA in addition to the deletion type, and they showed bands corresponding to 117 kDa as well as 110 and 114 kDa. The 117-kDa band was detectable by an anti-exon 3 peptide antibody. These results suggest that diversity among the tissue type calpastatins is caused by both alternative splicing and post-translational processing whereas the apparent conversion from the tissue type to the erythrocyte type is caused by proteolytic processing.

Complete variable region deletion in a mu heavy chain disease protein (ROUL). Correlation with light chain secretion

In a patient affected with chronic lymphocytic leukemia with lymphocyte surface mu and kappa determinants and vacuolated bone marrow plasma cells, the serum contained polymers of a truncated mu chain and normal-sized kappa chains. These light chains were present as monomers and covalent dimers in studies performed under dissociating conditions, but they were linked by non-covalent bridges to a portion of the serum short mu chains. The patient's urine contained a kappa type Bence-Jones protein. Study of a messenger RNA and complementary DNA from blood cells showed the abnormal mu chain to lack the entire variable region, likely due to a direct splicing of the leader peptide exon onto the CH1 exon. The production of light chains, a rare event in heavy chain diseases, appears to correlate with the occurrence of a heavy chain deletion restricted to the variable domain, likely because the non-covalently linked light chains allow these unusual heavy chains to be secreted.

Amyloid precursor protein mRNA levels in the mononuclear blood cells of Alzheimer's and Down's patients

Amyloid precursor protein (APP) is expressed by many non-neural tissues and it is possible that over-expression of the APP gene in non-neural tissue is responsible for the deposition of amyloid beta-protein in the brain and elsewhere. One possible source of beta-protein is circulating mononuclear blood cells which have previously been shown to express APP. To test this hypothesis, RNA was isolated from the mononuclear blood cells of patients suffering from Alzheimer's disease (n = 27), Down's syndrome (n = 13), senile dementia non-Alzheimer type (n = 14) and from normal individuals (n = 48). The relative abundance of mRNA coding for different splicing variants of the amyloid precursor protein (APP) mRNA was measured using multiprobe oligonucleotide solution hybridisation (MOSH). There was no significant difference in APP mRNA levels between any of the groups. This indicates that Alzheimer's disease is not characterised by an increase in production of APP in circulating mononuclear blood cells.

Thyroid hormone status correlates inversely with expression of the growth hormone receptor gene in rats immediately after birth

To investigate the role of thyroid hormone in the expression of the gene encoding the growth hormone receptor (GHR) and growth hormone binding protein (GHBP), fetal rats were made hypothyroid through the administration of the goitrogen methimazole to the mother. Euthyroidism was maintained in the mother by concurrent administration of L-thyroxine, which crosses the placenta poorly. Methimazole and L-thyroxine were continued in the mothers until weaning. After birth, groups of methimazole-treated or control pups were sacrificed immediately and at one, two, three, four, five, or six weeks after birth. In each group, weight was recorded, blood was obtained for measurement of T4, thyroid stimulating hormone (TSH), and growth hormone (GH), and liver tissue was obtained for quantitation of GHR and GHBP mRNA. The methimazole-treated pups were demonstrated to be hypothyroid, with markedly higher TSH and lower T4 concentrations, until weaning occurred between weeks three and four, after which they transiently became hyperthyroid at week five (T4 = 17 +/- 5 micrograms/dL vs. 6 +/- 0.5 micrograms/dL for controls) but returned to an euthyroid state at week six. In control pups the relative abundance of GHR and GHBP mRNA increased abruptly in week one, and increased three to four fold over the ensuing six weeks. Immediately after birth, the hypothyroid pups expressed significantly more GHR and GHBP mRNA than did the controls (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the Fc receptor for IgG (Fc gamma RII/CDw32) by human circulating T and B lymphocytes

Tissue-specific isoforms of the human FcR for IgG Fc gamma RII (CDw32) have previously been described by using mAb. These mAb were shown to exhibit different patterns of reactivity with lymphocytes. Among human PBL, Fc gamma RII has been detected on B cells but not T cells when assessed by flow cytometry and microscopy with the use of mAb KB61 and 41H16. Although KB61 and 41H16 were found to react with B cells, the mAb IV.3, CIKM5, and 2E1 did not react with any PBL subset. In this study, we show that KB61 and 41H16 react strongly with the majority (93-96%) of B cells (CD20+), and weakly with a proportion (18-42%) of T cells (CD3+), including 10 to 14% of CD4+ and 27 to 69% of CD8+ cells. In addition, mRNA for Fc gamma RII was detected in purified CD3+CD8high+ lymphocytes by polymerase chain reaction. KB61 and 41H16 also reacted with a majority of CD3-CD16/CD56+ cells, and CD3-CD20- cells. These findings indicate that a subset of T cells and non-T/non-B cells express Fc gamma RII, and are of interest in the light of previous studies which postulate that human Fc gamma R+ cells and Fc gamma RII+ murine T cells suppress the B cell immune response.

Detection of human interferon-alpha-encoding gene expression

We have devised a sensitive method based on the polymerase chain reaction (PCR) to detect expression of human interferon-alpha-encoding genes (IFN-A) in general, and specifically, expression of the IFN-A2 or IFN-A4 genes. The utility of the PCR approach was assessed by analysis of cloned IFN-A genes, as well as genomic DNA and mRNA isolated from peripheral blood mononuclear cells. We demonstrate the specific amplification of sequences encoding IFN subtypes IFN-alpha-2 and IFN-alpha-4 from as little as 0.1 pg of IFN-A mRNA. The PCR technique has potential clinical application for the detection of IFN-A expression and, thus, identification of the IFN-alpha subtypes produced, particularly in small biopsy samples or otherwise, where only low numbers of cells are available.

Molecular analysis of glycophorin C deficiency in human erythrocytes

Human erythrocyte glycophorin C plays a functionally important role in maintaining erythrocyte shape and regulating membrane mechanical stability. We report here the characterization of the glycophorins C and D deficiency in erythrocytes of the Leach phenotype. Glycophorin C gene is encoded by 4 exons. Amplification of reticulocyte cDNA from Leach phenotype and normal individuals generated a 140-bp fragment when using primers spanning exons 1 and 2. However, no polymerase chain reaction (PCR) products were detected in the Leach phenotype using primers flanking either exons 1 and 3 or exons 1 and 4, suggesting that the 3' end of the mRNA was missing or altered. Exon 4 also appeared to be missing from Leach genomic DNA, based on both Southern hybridization and PCR. These results indicate that an absence of glycophorin C and glycophorin D in erythrocytes from these Leach phenotype individuals is a consequence of a deletion or marked alteration of exon 3 and exon 4 of their glycophorin C gene. Surprisingly, the mutant gene encodes an mRNA stable enough to be detected in circulating reticulocytes. Although this mRNA could encode an N-terminal fragment of glycophorin C, these protein isoform(s) would not be expressed in the membrane because they lack the transmembrane and cytoplasmic domains.

A novel form of cytochrome P-450 family 4 in human polymorphonuclear leukocytes. cDNA cloning and expression of leukotriene B4 omega-hydroxylase

Isolation of cDNA clones for human leukotriene B4 (LTB4) omega-hydroxylase clearly demonstrates that the hydroxylase is a member of the cytochrome P-450 (CYP) superfamily. cDNA clones isolated from a human leukocyte cDNA library with CYP4A4 cDNA as a probe encode a protein of 520 amino acids with a molecular weight of 59,805. The deduced amino acid sequence contains an invariant cysteine in the conserved heme-binding domain near the C terminus, characteristic of the P-450 superfamily. The microsomes from yeast cells transfected with an expression vector pAAH5 carrying isolated cDNA catalyzed the omega-hydroxylation of LTB4 with a Km value of 0.71 microM, and its activity was significantly inhibited by carbon monoxide and by antisera against CYP4A4, consistent with the properties previously reported with LTB4 omega-hydroxylase in human polymorphonuclear leukocytes. The amino acid sequence of LTB4 omega-hydroxylase (P-450LTB omega) shows 31-44% similarity to those of CYP4A, CYP4B, and CYP4C, whereas less than 25% similarity was observed with any of the other P-450 families. According to the systematic classification of the P-450 superfamily, P-450LTB omega is classified into the CYP4 family but does not belong to any of the known CYP4 subfamilies. This P-450 composes a new subfamily of CYP4. RNA blot analysis indicated that mRNA hybridized to the cDNA was expressed in the polymorphonuclear leukocytes as well as leukocytes from four individuals. Isolation of the cDNA opens the way to investigate the physiological role and to regulation of the omega-hydroxylase in the inflammation process.

Distinct fetal Ank-1 and Ank-2 related proteins and mRNAs in normal and nb/nb mice

Mice homozygous for the mutation normoblastosis (gene symbol nb on chromosome 8) are deficient in erythroid ankyrin (ANK-1) and have a severe hemolytic anemia throughout life. Characteristic of the disease is a dramatic decrease in the level of expression of the Ank-1 gene (chromosome 8). The other major ankyrin transcript, brain ankyrin (Ank-2 on chromosome 3) is expressed at normal levels in nb/nb mice. Surprisingly, nb/nb fetuses have normal erythrocyte counts despite the decreased levels of Ank-1 transcripts. We previously hypothesized that fetal-specific ankyrin-related proteins could exist in nb/nb fetuses to account for the lack of detrimental effects of ANK-1 deficiency. In the present report, Western and Northern blot analyses were performed on hematopoietic cells isolated from nb/nb and +/+ fetuses. An ANK-1-related protein (165 Kd) in fetal reticulocytes persisted in adult nb/nb but not in +/+ reticulocytes. An Ank-1-related transcript of 5.5 kb was found in fetal reticulocytes. This transcript appeared to be upregulated in nb/nb but not in +/+ adult reticulocytes. A fetal-specific ANK-2-related protein (155 Kd) was present in nb/nb and in +/+ fetal reticulocytes. Ank-2-related fetal liver mRNAs were present during the time the liver was actively generating erythrocytes. Neither the Ank-2-related transcripts nor the 155-Kd ANK-2-related protein were found in +/+ or mutant adult reticulocytes. The data indicate that (1) unique ankyrin-related proteins and mRNAs present in fetal erythrocytes may stabilize the ankyrin-deficient nb/nb erythrocytes and (2) adult nb/nb mice may upregulate fetal gene transcripts to compensate for the ANK-1 deficiency.

Glanzmann's thrombasthenia caused by homozygosity for a splice defect that leads to deletion of the first coding exon of the glycoprotein IIIa mRNA

Glanzmann's thrombasthenia (GT) is the result of the absence or of an altered and dysfunctional expression on the platelet membrane of the fibrinogen receptor (glycoprotein [GP] IIb/IIIa complex). Various molecular genetic mechanisms have been found to be responsible for this inherited disease. In a patient with a severe type of GT, we have found a splice variant in the GP IIIa gene that leads to premature chain termination. Immunoprecipitation experiments, using monoclonal antibodies specific for GP IIb/IIIa, showed that GP IIb/IIIa was not detectable on the platelet membrane. Amplification of reversely transcribed platelet GP IIIa mRNA by the polymerase chain reaction and subsequent sequence analysis showed a 86-bp deletion, which corresponds to exon i of the GP IIIa gene. This deletion results in a shift of the reading frame leading to eight altered amino acids followed by a premature termination codon. Analysis of the corresponding genomic DNA fragments showed three mutations in the exon i-intron i boundary region of the GP IIIa gene. One of these mutations is a G-->T transition that eliminates the GT splice donor site in the wild type. This base pair change creates a restriction site for the enzyme Mse I. Allele-specific restriction enzyme analysis (ASRA) with Mse I of amplified genomic DNA of the parents and the proposita showed that both parents (who are first cousins) are heterozygous, whereas the proposita is homozygous for the G-->T substitution.

The effect of thyroidectomy on growth hormone regulation in the ovine fetus

To test the hypothesis that growth hormone gene messenger RNA abundance in the fetus is subject to the same effects of thyroid hormone previously demonstrated in other situations, we evaluated the effect of thyroidectomy on pituitary GH mRNA content at three gestational ages in the ovine fetus. One of each twin pair of fetal lambs underwent thyroidectomy at 90, 100 or 110 days gestation. Fetal pituitaries were collected 25-30 days later. Plasma GH and IGF-I were measured as well as pituitary GH mRNA content. Serum growth hormone in the thyroidectomy group was less than in the control twins (129.8 vs 187.6 micrograms/l, P = 0.0. GH mRNA was likewise decreased in pituitaries of thyroidectomy fetuses compared to controls (1.01 vs 1.80 units, P = 0.0006). Serum IGF-I and body weight were similar in the thyroidectomy and control twins. We conclude that the ovine fetus in the final trimester of gestation exhibits effects of thyroid hormone on serum GH and mRNA abundance similar to those seen in postnatal animals.

Presence of the entire coding region of GP IV mRNA in Nak(a)-negative platelets

It has been reported that Nak(a)-negative platelets lack GP IV. To examine the GP IV genetic defects in Nak(a)-negative platelets, we studied four unrelated Nak(a)-negative subjects by amplifying their GP IV cDNA, which were synthesized from platelet mRNA using the reverse transcriptase/polymerase chain reaction (RT/PCR). We detected the entire coding region of GP IV mRNA in the platelets of all four subjects. Restriction enzyme analysis of the amplified GP IV cDNA showed fully predictable cutting sites. These results suggest that no gross deletion or insertion had occurred in the GP IV mRNA of Nak(a)-negative platelets.

Tolerance to endotoxin-induced expression of the interleukin-1 beta gene in blood neutrophils of humans with the sepsis syndrome

The induction of genes of host cells stimulated by microbial products such as endotoxin and the tolerance of cells to endotoxin excitation play critical roles in the pathogenesis of microbial-induced acute disseminated inflammation with multiorgan failure (the sepsis syndrome). One gene that is induced in phagocytic cells by endotoxin and that appears to play an essential role in the pathogenesis of the sepsis syndrome is IL-1 beta. We report here that blood neutrophils (PMN) of patients with the sepsis syndrome (sepsis PMN) are consistently tolerant to endotoxin-induced expression of the IL-1 beta gene, as determined by decreased synthesis of the IL-1 beta protein and reductions in IL-1 beta mRNA. This down-regulation of the IL-1 beta gene in sepsis PMN occurs concomitant with an upregulation in the constitutive expression of the type 2 IL-1 receptor (IL-1R2). These phenotypic changes do not persist in PMN of patients recovering from the sepsis syndrome. Tolerance has stimulus and response specificity since sepsis PMN tolerant to endotoxin can respond normally to Staphylococcus aureus stimulation of IL-1 beta production and they normally secrete elastase. Uninfected patients with severe trauma or shock from causes are not tolerant to endotoxin and tolerance is not limited to patients infected with Gram-negative bacteria. The mechanism responsible for tolerance involves pretranslational events and is not due to loss of the CD14 surface protein, a receptor required for endotoxin induction of IL-1 beta in PMN. The physiological significance of the tolerance to endotoxin and increased expression of IL-1R2 on sepsis PMN is unknown, but may represent an attempt by the host to protect itself from the deleterious effects of disseminated inflammation.

Factors related to the recurrent hyperfunction of autografts after total parathyroidectomy in patients with severe secondary hyperparathyroidism

Total parathyroidectomy with autotransplantation has been widely accepted as the appropriate treatment for patients with hyperparathyroidism due to chronic renal failure on long term hemodialysis. However, recurrence has been an enigma and therefore, the factors involved in the recurrence of hyperparathyroidism were studied in 128 patients followed for more than 2 years after surgical treatment. The preoperative serum parathyroid hormone (PTH) concentrations correlated with the total weights of the parathyroid glands. When the original autotransplanted glands were divided into two groups, being diffuse and nodular, the rate of recurrent hyperparathyroidism due to graft hyperfunction was significantly higher in the patients who received nodular glands (24%) than in those who received diffuse glands (8.4%) (P < 0.05). To investigate whether PTH synthetic activity is different in diffuse and nodular glands, the amount of PTH mRNA was studied by in situ hybridization. There was no significant difference in the amount of PTH mRNA in the cells from either diffuse or nodular glands. These data suggest that the recurrence of hyperparathyroidism is not due to enhanced PTH synthetic activity of autotransplant grafts but to the abnormal growth rate of the transplanted gland.

Angiotensin I-converting enzyme in human circulating mononuclear cells: genetic polymorphism of expression in T-lymphocytes

The expression of angiotensin-I converting enzyme (ACE; EC 3.4.15.1) in human circulating mononuclear cells was studied. T-lymphocytes contained the highest level of enzyme, approx. 28 times more per cell than monocytes. No activity was detected in B-lymphocytes. ACE was present mainly in the microsomal fraction, where it was found to be the major membrane-bound bradykinin-inactivating enzyme. An mRNA for ACE was detected and characterized after reverse transcription and amplification by PCR in T-lymphocytes and several T-cell leukaemia cell lines. We have previously observed that the interindividual variability in the levels of ACE in plasma is, in part, genetically determined and influenced by an insertion/deletion polymorphism of the ACE gene. To investigate the mechanisms involved in the regulation of ACE biosynthesis, the ACE levels of T-lymphocytes from 35 healthy subjects having different ACE genotypes were studied. These levels varied widely between individuals but were highly reproducible and influenced by the polymorphism of the ACE gene. T-lymphocyte levels of ACE were significantly higher in subjects who were homozygote for the deletion than in the other subjects. These results show that ACE is expressed in T-lymphocytes and indicate that the level of ACE expression in cells synthesizing the enzyme is genetically determined.

Decreased messenger RNA of arachidonate 12-lipoxygenase in platelets of patients with myeloproliferative disorders

On the basis of the previous work by Okuma and Uchino [Blood 54, 1258-1271, 1979], three patients with myeloproliferative disorders were investigated with a special reference to arachidonate 12-lipoxygenase in their platelets. The cytosol of the patients' platelets showed a markedly reduced activity of arachidonic acid oxygenation to 12-hydroperoxy acid. A peroxidase-linked immunoassay for the 12-lipoxygenase demonstrated only 7-12% of the normal level of the enzyme protein in the cytosol fraction of platelets. Furthermore, 12-lipoxygenase mRNA level was determined quantitatively by a reverse transcriptase-polymerase chain reaction with an internal standard cRNA which was synthesized by in vitro transcription of human platelet 12-lipoxygenase cDNA with a 105-bp deletion. The 12-lipoxygenase mRNA content was 4.7 +/- 2.0 (mean +/- S.D.) ng/10(11) platelets in 13 normal subjects. In contrast, the mRNA content was as low as 0.15, 0.11 and 0.10 ng/10(11) platelets in the three patients. Taken together, the 12-lipoxygenase deficiency in these patients was attributable to the decreased 12-lipoxygenase mRNA level and thus the impaired synthesis of the enzyme protein in their platelets.

Effect of granulocyte-macrophage colony-stimulating factor and interleukin-3 on interleukin-8 production by human neutrophils and monocytes

Interleukin-8 (IL-8) is a major neutrophil chemoattractant and functional stimulant that is induced by IL-1, tumor necrosis factor alpha (TNF alpha), and lipopolysaccharide (LPS). We report that recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF) and rhIL-3 are also potent inducers of IL-8 messenger RNA (mRNA) accumulation and protein secretion by normal peripheral blood monocytes. Neutrophils produce IL-8 in response to GM-CSF but not to IL-3. In contrast, recombinant human granulocyte-CSF (rhG-CSF), at concentrations as high as 100 ng/mL, does not induce IL-8 in either cell type. rhGM-CSF also induces IL-8 mRNA expression and IL-8 protein in the promonocytic cell line, U-937, whereas rhG-CSF does not. IL-8 secretion by monocytes was stimulated within 2 hours after incubation with rhGM-CSF or rhIL-3. Stimulation of neutrophils with rhGM-CSF resulted in an increase in cell-associated IL-8 at 4 hours. At 24 hours, cell-associated IL-8 levels declined, whereas secreted IL-8 levels increased. In contrast, virtually all IL-8 induced in monocytes appeared as secreted protein. Neither rhGM-CSF nor rhIL-3 induced detectable secretion of IL-1, TNF alpha, or IL-6 protein by monocytes. rhGM-CSF, and to a lesser degree rhIL-3, potently stimulated IL-8 secretion in cultures of heparinized whole blood, whereas rhG-CSF had no significant effect on IL-8 secretion. Induction of IL-8 by GM-CSF may be physiologically important in enhancing the acute inflammatory response.

Identification of tissue kallikrein messenger RNA in human neutrophils

Expression of tissue kallikrein in human neutrophils has been suggested by previous studies using enzymatic and immunochemical techniques. Secretion of this potent biological factor by neutrophils would be of marked significance in the inflammatory process. The present study utilized the polymerase chain reaction following reverse transcriptase generation of total neutrophils cDNA to demonstrate the presence of tissue kallikrein mRNA in the human neutrophils. In addition, use of sequence-specific primers demonstrated the presence of mRNA for the hGK-1 gene, but not for the hPK gene product or the gene for prostate-specific antigen. These results confirm that tissue kallikrein is present in neutrophils and may be secreted as part of the inflammatory process.

Assessment of G-CSF and GM-CSF mRNA expression in peripheral blood mononuclear cells from patients with severe congenital neutropenia and in human myeloid leukemic cell lines

Patients with severe congenital neutropenia (SCN), also called Kostmann syndrome, are unable to generate sufficient peripheral blood granulocytes owing to an arrest of myeloid differentiation at the level of promyelocytes. Similarly, myeloid leukemic cells show a maturation arrest at different stages of myeloid maturation coupled with uncontrolled proliferation. Among other cells, defective production of or defective response to granulocyte/macrophage colony-stimulating factor (GM-CSF) or granulocyte CSF (G-CSF) might be involved in the pathophysiology of these disorders of hematopoiesis. Reverse transcription of messenger RNA and subsequent specific amplification by the polymerase chain reaction (RT-PCR) served as a sensitive technique to detect G-CSF and GM-CSF gene expression. We have tested two alternative assays for the specific quantitation of transcript levels for G-CSF. Applying one assay we could demonstrate that: 1) peripheral blood monocytes from 5 patients with SCN are able to express G-CSF and GM-CSF messenger RNA, suggesting that defective production of these factors is not responsible for the neutropenia in this condition; 2) messenger RNA levels from 5 SCN patients were on average higher than the levels determined for three healthy volunteers; 3) 7 of 9 of the examined myeloid cell lines express GM-CSF and all of them G-CSF mRNA. These results show that quantitative PCR techniques can be used as simple tools to elucidate aspects of the pathophysiology of hematologic disorders concerning the production of CSFs.

Adherence in combination with lipopolysaccharide, tumor necrosis factor or interleukin-1 beta potentiates the induction of monocyte-derived interleukin-8

In this study we demonstrate that adherence of peripheral blood mononuclear cells (PBMC) to either plastic or extracellular matrix, such as collagen type I or fibronectin, is a significant stimulus for the induction of both interleukin-8 (IL-8) mRNA and antigen. In addition, adherence of PBMC in the presence of lipopolysaccharide, interleukin-1-beta, or tumor necrosis factor-alpha greatly enhances transcription/translation of IL-8 from these leukocytes. Our findings demonstrate that PBMC adherent to either plastic or physiological surfaces in combination with an inflammatory agonist is both a potent and efficacious signal for the expression and production of the neutrophil chemotactic/activating cytokine, IL-8.

The "b" mutated gene in heterozygous Belgrade anemic rat

The Belgrade b/b rat has an autosomal recessive mutation which in homozygous state induces severe anemia. So far, this mutation has been considered a recessive one and the heterozygous animals (+/b) as phenotypically normal. In this study, we showed that at the hematologic level, the heterozygous animals acquire some of the anemic characteristics as well. Namely, the young +/b animal displays reticulocytosis of 3.1 +/- 1.0%, identical to b/b rat, compared with 0.8 +/- 0.4% in young normal animals. This conclusion was further supported by examination of beta-globin expression. The level of beta-globin mRNA in anemic and heterozygous reticulocytes is decreased, as estimated by dot blot hybridization, to 25% and 50% of normal level, respectively. Although inapparent phenotypically, b mutated allele disturbs early erythropoiesis and markedly decreases globin mRNA level in the heterozygous rat.

Erythrophagocytosis increases the expression of erythroid potentiating activity mRNA in human monocyte-macrophages

The aim of the present study was to evaluate whether the erythropoietic response to hemolysis can be mediated by other regulatory peptides in addition to erythropoietin. For this purpose, we have investigated the influence of erythrophagocytosis by human monocytes and macrophages on the mRNA expression of several growth factor genes, including interleukin-3 (IL-3), granulocyte/macrophage colony-stimulating factor (GM-CSF) and erythroid potentiating activity (EPA), which are supposed to influence erythropoiesis. Immunologically mediated erythrophagocytosis increased the expression of EPA mRNA (2 to 3 times). Such increase appeared to be specifically associated with phagocytosis of erythrocytes, since phagocytosis of yeast microorganisms or antibody-coated latex particles had no effect on EPA gene expression. Yeast, however, powerfully stimulated the expression of GM-CSF, granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6) mRNAs which, with the exception of G-CSF, were not influenced by erythrophagocytosis. Erythropoietin and IL-3 mRNAs were never detected in cultured monocytes, either in control or in treated samples. Our findings may suggest that phagocytosis of erythrocytes by monocytes/macrophages increases the expression, and possibly the production, of EPA. This could in turn potentiate the erythropoietic response to extravascular hemolysis by increasing the number of cells responsive to erythropoietin. Thus, EPA might be a mediator of an end-product positive feedback on the rate of red cell production.

Pro- and anti-inflammatory cytokines in primary systemic vasculitis

The expression of cytokines that are potentially involved in the pathogenesis of vasculitis was studied in patients with primary systemic vasculitis (PSV). In extension of earlier reports, we detected an overexpression of transforming growth factor beta (TGF beta), interleukin 6 (IL6), and interleukin 8 (IL8), indicating that the whole cytokine cascade is activated to a significant extent in PSV.

Modulation of macrophage Fc gamma receptors by rGM-CSF

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor being used increasingly to support white blood cell counts in hematologic disorders. Since the survival of IgG-sensitized cells following blood transfusions and the clearance of immune complexes are important in these disorders, we investigated the effect of GM-CSF on the Fc gamma receptors largely responsible for this immune clearance. Human monocytes were cultured in buffer or 100 U/mL of recombinant GM-CSF (rGM-CSF) for 48 hours. Flow cytometry was used to evaluate changes in the expression of the three Fc gamma receptors. Fc gamma RII was the only Fc gamma receptor significantly increased by rGM-CSF. This increase in Fc gamma RII surface protein was correlated with an increase in macrophage binding of erythrocytes sensitized with IgG. In addition, an increase in monocyte binding of IgG-sensitized RBCs was observed in RBCs sensitized with murine IgG2b antibody, which preferentially binds to Fc gamma RII. rGM-CSF also increased the monocyte Fc gamma RII-dependent low-affinity binding site for trimeric IgG. Furthermore, rGM-CSF was observed to increase the expression of monocyte Fc gamma RII mRNA, including that for Fc gamma RIIA. Thus, these studies demonstrate that GM-CSF increases monocyte Fc gamma RII expression and function and suggests that a similar process may be present in vivo. This effect may be either beneficial (increased clearance of immune complexes) and/or detrimental (increased transfusion requirements) in select patients.

Molecular profile of human immunodeficiency virus type 1 infection in symptomless patients and in patients with AIDS

Recent molecular evidence indicates that active human immunodeficiency virus type 1 (HIV-1) infection is detectable in both symptomless and symptomatic infected patients. For this main reason, it has been pointed out that precise quantitative analysis of viral activity in vivo is necessary, firstly, for the pathogenetic investigation of the steps relevant to infection progression and, secondly, for better clinical management of HIV-1-infected patients. In this study, the presence of HIV-1 genomic RNA in plasma samples, specific HIV-1 transcripts in peripheral blood mononuclear cells, and proviral DNA sequences were assayed for 33 HIV-1-infected patients (including symptomless and symptomatic subjects) by using a competitive polymerase chain reaction method that allows quantitation of the RNA/DNA target sequences. The quantitative results obtained confirm that transcription of HIV-1 structural genes and complete viral replication occur in all the HIV-1-infected patients independently of the clinical stage. However, although sharp individual differences were detected, a high degree of correlation of the molecular parameters studied with both disease progression and a decrease in the number of CD4+ T lymphocytes was documented. Interestingly, despite the increasing viremia level associated with infection progression, the mean transcriptional activity of individual infected cells was found to be only moderately greater in AIDS patients than in asymptomatic infected subjects. In addition, it was noted that quantitation of HIV-1 genomic RNA in plasma samples and quantitation of specific HIV-1 transcripts in peripheral blood mononuclear cells appear to be more reliable and sensitive markers of viral activity than quantitative analysis of proviral HIV-1 sequences in peripheral lymphocytes.

Eosinophil IgE receptor and CD23

In the present review, eosinophil Fc epsilon RII was compared to CD23, a differentiation marker of B cells. Biochemical analysis revealed that molecules of similar molecular weight were immunoprecipitated from eosinophils and B cells by an anti-CD23 monoclonal antibody (mAb) or by BB10, and anti-eosinophil Fc epsilon RII. By flow cytometry, a correlation was found between the binding of anti-CD23 mAb and myeloma IgE. However, a low expression of different epitopes of CD23 was observed in various hypereosinophilic patients. Northern blot analysis of eosinophil RNA with the cDNA probe of CD23 revealed a weak message in only 3 of the 6 patients expressing membrane CD23. The inhibition by anti-CD23 mAbs of IgE-mediated cytotoxicity and IgE binding to eosinophils clearly indicated the participation of CD23 or a related molecule in IgE-dependent eosinophil functions. However, the differential effects of anti-CD23 mAbs on eosinophils and B cells suggest major differences in the characteristics of the molecule expressed by eosinophils and by B cells.

Prevalent skipping of an individual exon accounts for shortened protein 4.1 Presles

An asymptomatic shortened variant of protein 4.1 (-8.5 Kd) was first recognized in the red blood cells and designated protein 4.1 Presles. We show here that the missing segment belongs to the 22/24 Kd domain. Protein 4.1 cDNA from reticulocytes was amplified, mapped, and sequenced. The truncation appeared to result from the prevalent skipping of an individual and alternatively spliced exon, also called motif II, whereas this motif is preferentially retained under normal conditions. The same phenomenon was observed in lympho-blastoid cells. Sequencing over 80 bp of intronic sequences 5' and 3' of motif II failed to reveal any change. A new alternative splice site was incidently found 81 nucleotide downstream of motif II in both normal and truncated 4.1 mRNA.

Subpopulations of normal peripheral blood and bone marrow cells express a functional multidrug resistant phenotype

The multidrug-resistance gene, MDR1 is expressed in many normal tissues, but little is known about its expression in normal hematopoietic cells. Using the monoclonal antibody C219 and flow cytometric analysis, P-glycoprotein (P-gp) was found to be expressed in all peripheral blood (PB) subpopulations (CD4, CD8, CD14, CD19, CD56) except granulocytes. To specifically determine MDR1 gene expression, these PB subpopulations were isolated by fluorescence-activated cell sorting (FACS) and analyzed for MDR1 mRNA by polymerase chain reaction (PCR). All subsets were positive by PCR, but only minimal MDR1 mRNA was detected in monocytes and granulocytes. Significant efflux of Rhodamine-123 (Rh-123), a measure of P-gp function, was detected in CD4+, CD8+, CD14+, CD19+, and CD56+ cells but not in granulocytes. Next, PCR-analysis was performed on FACS-sorted bone marrow (BM) cells to assess MDR1 expression in different maturational stages. Precursors (CD34+), early and late myeloid cells (CD33+/CD34+, CD33+/CD34-) as well as lymphocytes of the B-cell lineage (CD19+/CD10+, CD19+/CD10-) expressed the MDR1 gene. BM monocytic cells (CD33++/CD34-) were negative, and a very weak signal was detected in erythroid cells (glycophorin A+). Significant Rh-123 efflux was found in CD34+, CD10+, CD33+, and CD33++ BM cells, but not in glycophorin A+ cells. We conclude that PB and BM lymphocytes, PB monocytes, BM progenitors, and immature myeloid cells, but not late BM monocytes, erythroid cells, and PB granulocytes, express MDR1 mRNA and a functional P-gp. These results have to be taken into account when MDR1 expression is determined in tumor samples containing normal blood cells.

Ser-752-->Pro mutation in the cytoplasmic domain of integrin beta 3 subunit and defective activation of platelet integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) in a variant of Glanzmann thrombasthenia

Integrins are membrane receptors which mediate cell-cell or cell-matrix adhesion. Integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) acts as a fibrinogen receptor of platelets and mediates platelet aggregation. Platelet activation is required for alpha IIb beta 3 to shift from noncompetent to competent for binding soluble fibrinogen. The steps involved in this transition are poorly understood. We have studied a variant of Glanzmann thrombasthenia, a congenital bleeding disorder characterized by absence of platelet aggregation and fibrinogen binding. The patient's platelets did not bind fibrinogen after platelet activation by ADP or thrombin, though his platelets contained alpha IIb beta 3. However, isolated alpha IIb beta 3 was able to bind to an Arg-Gly-Asp-Ser affinity column, and binding of soluble fibrinogen to the patient's platelets could be triggered by modulators of alpha IIb beta 3 conformation such as the Arg-Gly-Asp-Ser peptide and alpha-chymotrypsin. These data suggested that a functional Arg-Gly-Asp binding site was present within alpha IIb beta 3 and that the patient's defect was not secondary to a blockade of alpha IIb beta 3 in a noncompetent conformational state. This was evocative of a defect in the coupling between platelet activation and alpha IIb beta 3 up-regulation. We therefore sequenced the cytoplasmic domain of beta 3, following polymerase chain reaction (PCR) on platelet RNA, and found a T-->C mutation at nucleotide 2259, corresponding to a Ser-752-->Pro substitution. This mutation is likely to be responsible for the uncoupling of alpha IIb beta 3 from cellular activation because (i) it is not a polymorphism, (ii) it is the only mutation in the entire alpha IIb beta 3 sequence, and (iii) genetic analysis of the family showed that absence of the Pro-752 beta 3 allele was associated with the normal phenotype. Our data thus identify the C-terminal portion of the cytoplasmic domain of beta 3 as an intrinsic element in the coupling between alpha IIb beta 3 and platelet activation.

Decreased low-density lipoprotein receptor function and mRNA levels in lymphocytes from uremic patients

The mechanisms by which renal failure causes hyperlipoproteinemia remain unclear. To investigate the potential role of the low-density lipoprotein (LDL) receptor in lipoprotein metabolism in uremia we measured LDL receptor function in peripheral blood mononuclear cells (PBMC) from uremic patients and control subjects using a functional assay in which proliferation of lectin-stimulated PBMC in the presence of lovastatin was dependent upon internalization of exogenous cholesterol via a functional LDL receptor. The amount of LDL required to reverse 50% of lovastatin-induced inhibition of proliferation in PBMC from uremic patients was significantly greater (3.6 +/- 1.8 micrograms/ml, N = 33, P < 0.05) than controls, (1.99 +/- 0.6 micrograms/ml, N = 37). Abnormal LDL receptor function in four uremic patients normalized following renal transplantation. To investigate the molecular basis for LDL receptor dysfunction, we directly quantitated LDL receptor messenger RNA (mRNA) in PBMC from uremic patients and control subjects using a ribonuclease protection assay. LDL receptor mRNA expression in uremic patients was 0.42 +/- 0.08 (N = 10), significantly lower (P < 0.015) than in normal subjects, 0.71 +/- 0.08 (N = 14). These data suggest that an acquired defect in LDL receptor function in PBMC from uremic patients exists which may be due to decreased LDL receptor expression. These abnormalities, if present in other tissues, could contribute to the aberrant lipoprotein metabolism which is a consistent feature of uremia.

Detection of properdin mRNA in human peripheral blood monocytes and spleen

Properdin serves a critical role in the alternative pathway of complement by stabilizing the C3bBb complex. Early studies to determine the properdin sequence relied on amino acid sequencing of enzymatically cleaved properdin and only yielded partial sequence data. Recently Nolan et al. reported a properdin mRNA sequence obtained from the U937 myelomonocytic cell line. We sought to detect properdin mRNA in two normal human tissues and to compare those sequences with that obtained from the U937 cell line. Cytoplasmic RNA harvested from human spleen and peripheral blood monocytes served as a template for first strand synthesis. The cDNA was then used as a template for polymerase chain reaction. A properdin message was detected in both spleen and peripheral blood monocytes but not in peripheral blood neutrophils. The sequence was nearly identical to that obtained from the U937 cell line. These experiments demonstrate that peripheral blood may be used as a ready source for properdin mRNA and will faster studies to define the defect in properdin-deficient patients.

Mutations in severe, type III von Willebrand's disease in the Dutch population: candidate missense and nonsense mutations associated with reduced levels of von Willebrand factor messenger RNA

The von Willebrand factor (vWF) genes of nine unrelated, severe, type III von Willebrand's disease (vWD) patients (six of Dutch origin) and four unrelated Dutch type I vWD patients were screened for mutations in exons that contain CGA codons (Arg), which are liable to mutation to TGA stop codons. The nine exons of the vWF gene (3, 8, 9, 10, 28, 31, 32, 43 and 45) that contain all the CGA codons (11 in total) of the vWF cDNA were amplified by the polymerase chain reaction and screened for mutations by single-strand conformation polymorphism analysis, restriction enzyme - and/or nucleotide sequence analysis. Three of the severe vWD patients were found to be heterozygous for a nonsense mutation: CGA Arg 2535-->TGA Stop. Three other severe vWD patients were homozygous for a single nucleotide substitution, AAC Asn 2546-->TAC Tyr. The transcription of these mutated alleles was tested by cDNA dependent amplification of platelet RNA. The level of transcription product was strongly reduced for either mutant allele.

Expression of 92-kDa type IV collagenase mRNA by eosinophils associated with basal cell carcinoma

Metalloproteinases are thought to be important for tumor invasion and metastasis. We used in situ hybridization with 35S-labeled cRNA probes to localize sites of expression for 92-kDa type IV collagenase mRNA in sections of nodular basal cell carcinoma. Positive signal for 92-kDa type IV collagenase mRNA was detected in eosinophilic granulocytes within inflammatory infiltrates surrounding the tumor nodules. Eosinophils, however, were not adjacent to tumor cells, suggesting that metalloenzyme production by these granulocytes in this disease may be targeted more to stromal components than to remodeling or destruction of the basement lamina. The identity of the eosinophils was confirmed by cell morphology and specific histochemical staining. No resident or other migratory cells were positive for enzyme mRNA in these samples. Signal specificity for in situ hybridization was shown by a duplication of the results with complementary oligomeric probes and by a lack of signal in sections hybridized with a sense RNA probe or nonspecific oligomer. No signal for 92-kDa type IV collagenase mRNA was detected in circulating eosinophils or in eosinophils associated with Hodgkin's lymphoma. These data suggest that eosinophils migrate into the dermis and express type IV collagenase in response to basal cell carcinoma and that this process may have a role in tumor growth.

Splice site mutations are a common cause of X-linked chronic granulomatous disease

Chronic granulomatous disease (CGD) is characterized by the absence of a respiratory burst in activated phagocytes. Defects in at least four different genes lead to CGD. Patients with the X-linked form of CGD have mutations in the gene for the beta-subunit of cytochrome b558 (gp91-phox). We studied the molecular defect in four patients with X-linked CGD. In a fifth family, we studied the mother of a patient with X-linked CGD who had died before our investigations. Gp91-phox messenger RNA (mRNA) was reverse transcribed into cDNA and the coding region was amplified by polymerase chain reaction into three fragments. Sequence analysis showed the absence of the exon 7, 5, 3, and 2 sequences in patients 1, 2, 3, and 4, respectively. In carrier 5, we found both normal cDNA and cDNA that lacked 57 3'-nucleotides of exon 6. We analyzed the splice sites of the flanking introns of the missing exons. In patients 1, 2, and 3, we found single nucleotide substitutions within the first five positions of the down-stream 5' donor splice sites. In patient 4, a similar substitution was found at position -1 of the 3' acceptor splice site of intron 1. In carrier 5, no mutation was found in the exon 6-intron 6 boundary sequence. Instead, a single substitution was observed in exon 6 (C----A at nucleotide 633) that created a new donor splice site. Apparently, mRNA splicing occurs preferentially at this newly created splice site. We conclude that the absence of the exon sequences in the gp91-phox mRNA of these patients is due to splicing errors. Of 30 European X-linked CGD patients studied by us so far, five appear to be caused by mutations that affect correct mRNA splicing. Thus, such mutations appear to be a common cause of X-linked CGD.

A soluble form of the glycolipid-anchored receptor for urokinase-type plasminogen activator is secreted from peripheral blood leukocytes from patients with paroxysmal nocturnal hemoglobinuria

The cellular urokinase-type plasminogen-activator (uPA) receptor (uPAR) is a glycolipid-anchored membrane protein thought to be involved in pericellular proteolysis during cell migration and tumor invasion. In the present study, we have identified and characterized two soluble forms of uPAR which have retained their ligand-binding capability. One variant was generated in vitro by treatment of intact normal cells with either a phosphatidylinositol-specific phospholipase C (PLC) or endoproteinase Asp-N. The other soluble uPAR variant was secreted in vivo from peripheral blood leukocytes affected by the stem-cell disorder paroxysmal nocturnal hemoglobinuria (PNH), and was found in the plasma from these PNH patients as well as in the conditioned medium from cultured PNH leukocytes. Under normal conditions, we find no evidence for any shedding or secretion of a soluble uPA-binding counterpart to human uPAR in plasma. Unlike normal leukocytes, the PNH-affected cells do not express uPAR on the cell surface, although they do contain apparently normal levels of uPAR-specific mRNA. The secreted uPAR derived from PNH cells has a mobility in SDS/PAGE that is slightly higher than that of uPAR solubilized by PtdIns-specific PLC or detergent, but resembles that of a truncated, recombinant uPAR variant, which has its C-terminus close to the proposed glycolipid-attachment site, suggesting that the secreted protein has been proteolytically processed for glycolipid attachment. The presence in plasma from PNH patients of such a secreted, hydrophilic form of uPAR lends support to the hypothesis that the lesion underlying the PNH disorder resides either in glycolipid biosynthesis or in the function of an as-yet-unidentified transamidating enzyme assumed to cleave and assemble the truncated uPAR with the preformed glycolipid moiety.

Alpha-1 antitrypsin response of stimulated alveolar macrophages

Alpha-1 antitrypsin messenger RNA (A1AT mRNA) was determined in alveolar macrophages and in peripheral blood monocytes of healthy individuals using a sensitive RNase protection assay. Determinations were made of bacterial lipopolysaccharide (LPS) stimulated and unstimulated cells. We found that the amount of A1AT mRNA increased 7.3 and 14 times after 4 h of incubation with LPS for monocytes and macrophages, respectively (relative to total RNA). The increase was 12.3 and 14.8 times, respectively, when expressed as increase per cell. In both cell types there was wide interindividual variation in LPS response: 2-36 and 5-12 times for monocytes and macrophages, respectively. The possible significance of A1AT production of monocytes and macrophages may be the local control of granulocytic proteases such as elastase and cathepsin G.

Hepatic fibrosis in rats produced by carbon tetrachloride and dimethylnitrosamine: observations suggesting immunoassays of serum for the 7S fragment of type IV collagen are a more sensitive index of liver damage than immunoassays for the NH2-terminal propeptide of type III procollagen

Liver fibrosis was induced in rats both with carbon tetrachloride and dimethylnitrosamine. Assays were performed on steady-state levels of messenger RNAs in the liver for several collagens and basement membrane components. The results indicated marked increases in the steady-state levels of messenger RNA for type I collagen, type III collagen, type IV collagen and the B2 component of laminin. In the same animals, immunoassays were performed for serum levels of the N-terminal propeptide of type III procollagen and the 7S fragment of type IV collagen. The results demonstrated an increase in the serum levels of 7S fragment that occurred early and closely paralleled the increase in the steady-state levels of messenger RNA for the alpha 1(IV) chain of type IV collagen. In contrast, no significant increase was seen in the serum levels of the N-propeptide of type III procollagen. The results suggest that immunoassays for 7S fragment of type IV collagen in serum are a more sensitive index for liver cell damage and fibrosis than assays for the N-propeptide of type III procollagen. The results suggest that greater attention should be paid to assays of 7S fragments in assessing hepatic fibrosis in man.

Molecular basis for Glanzmann's thrombasthenia (GT) in a compound heterozygote with glycoprotein IIb gene: a proposal for the classification of GT based on the biosynthetic pathway of glycoprotein IIb-IIIa complex

The genetic basis for Glanzmann's thrombasthenia (GT) was elucidated on a compound heterozygote with glycoprotein (GP)IIb gene: an opal mutation at the end of exon 17 (CGA----TGA) results in only a trace amount of GPIIb mRNA, and a splicing mutation at the acceptor site of exon 26 (CAG----GAG) causes an in-frame, exon skipping process from exon 25 to 27. This aberrant transcript encodes a single-chain polypeptide characterized by a 42-amino acid deletion, which includes the proteolytic cleavage site(s) and a unique, proline-rich region at the location corresponding to the carboxyl-terminal of the normal GPIIb alpha-chain. These characteristics are shared by a previously reported defective GPIIb molecule, which is neither assembled with GPIIIa nor transported to the cellular surface. Despite its normal transcription level, expression of the present defective GPIIb molecule was significantly decreased (approximately 6% of the control level). Because the precursor GPIIb molecule is assembled with GPIIIa in the endoplasmic reticulum (ER) and its processing, as well as stability, is dependent on the GPIIIa subunit, the defective GPIIb molecule may be rapidly degraded by the intrinsic quality control system of the ER due to its inability to form a stable heterodimer complex as a consequence of its misfolded structure. Although we did not confirm that the GPIIIa genes of this individual were normal, GPIIIa may be secondarily decreased (approximately 11% of control), because a large part of it could not be complexed, making it vulnerable to proteolysis. To elucidate the molecular basis for GT, we propose here a classification of GT based on the biosynthetic pathway of the GPIIb-IIIa complex.

Prolonged elevation of interleukin-8 and interleukin-6 concentrations in plasma and of leukocyte interleukin-8 mRNA levels during septicemic and localized Pseudomonas pseudomallei infection

Patients suffering from serious bacterial infection present to the hospital after early inflammatory events, such as release of tumor necrosis factor (TNF), have been initiated. The role of other cytokines, such as interleukin-8 (IL-8), a neutrophil chemoattractant and activator, in the pathophysiology of human sepsis is not well characterized, and there are only limited data on IL-6. We studied serial concentrations of TNF, IL-6 (involved in the acute-phase response), and IL-8 in plasma and leukocyte levels of mRNA for these cytokines in patients with localized and septicemic Pseudomonas pseudomallei infection on admission to the hospital and during a prolonged recovery phase (up to 30 days). Of 18 patients, 8 had detectable plasma IL-8 and all had raised plasma IL-6 concentrations. In patients who died median initial concentration of IL-8 (167 pg/ml; range, 97 to 362 pg/ml) and IL-6 (4,800 pg/ml; range, 60 to 9,245 pg/ml) in plasma were higher than those in survivors (P less than 0.008 and P = 0.007, respectively). Septic patients who survived and patients with localized disease had similar cytokine levels. Plasma IL-8 and IL-6 concentrations were elevated throughout the inpatient period of recovery. Circulating leukocytes contained mRNA for IL-8 but not for IL-6 and TNF, and they may secrete IL-8. An elevated plasma IL-6 concentration (greater than 1,000 pg/ml) had 75% mortality) was the best predictor of mortality in P. pseudomallei sepsis. Fifty percent of patients with detectable plasma IL-8 concentrations died. In contrast, plasma TNF bioactivity did not relate to outcome; 75% of patients who did never had detectable plasma TNF activity.

Three distinct candidate point mutations of the von Willebrand factor gene in four patients with type IIA von Willebrand disease

Type IIA von Willebrand disease (vWD) is the most common type II vWD and is characterized by the selective loss of large and intermediate sized multimers. One explanation for this disorder has been postulated to be a qualitative defect in von Willebrand factor (vWF) which results in increased susceptibility to proteolysis at the bond between residues Tyr842 and Met843. Four missense mutations that may cause type IIA vWD have recently been identified near the cleavage site. We analyzed the molecular basis for type IIA vWD in six patients. A 512 bp DNA sequence spanning the proteolytic cleavage site was targeted for PCR amplification and sequencing. We exploited a difference in restriction sites between the vWF gene and the pseudogene and have designed allele-specific oligomer used with PCR to distinguish these two genes. Three candidate missense mutations; Ser743 (TCG)----Leu (TTG), Leu799 (CTG)----Pro (CCG), and Arg834 (CGG)----Trp (TGG) were identified in 4 out of 6 patients. The amino acid substitution at Arg834 has been reported previously, but the other substitutions at Ser743 and Leu799 are novel candidate mutations locating 99 and 43 amino acids to the N-terminal side of the cleavage site, respectively. Our results indicate that amino acid substitutions located relatively distant from the cleavage site may also be involved in type IIA vWD.

Serum T-kininogen levels increase two to four months before death

We have reported an accumulation of T-kininogen mRNA in the liver of aging Sprague-Dawley rats. T-kininogen is a cysteine proteinase inhibitor. Since a disruption of the intracellular protein degradation machinery is known to occur during senescence, we wished to further define the role of this protein in the aging process. As a first step, we have measured T-kininogen levels both in serum and within the liver. We have found that serum protein levels are indeed augmented during senescence, although not as dramatically as the mRNA (2.5-fold versus 8.3-fold). Immunocytochemistry, as well as Western blot analysis suggests that this is due to the presence of T-kininogen within hepatic cells in aged rats. Life-long dietary restriction, a known age-prolonging treatment, decreases the overexpression of the protein in 24-month-old rats. Later, diet-restricted animals still show an increased expression from the gene, the effect being delayed but not abolished by dietary manipulation. Interestingly, a longitudinal study indicated the existence of a positive correlation between the time of increase of serum T-kininogen and the time of death of the animal. Serum T-kininogen was found to increase 2.5-4 months before death.

Decreased expression of eosinophil peroxidase and major basic protein messenger RNAs during eosinophil maturation

We evaluated the levels of mRNAs encoding cationic proteins in peripheral blood eosinophils (PBE) purified from patients with eosinophilia and in eosinophils differentiated from cord blood cells (CBC) by culture with recombinant human interleukin-3 (rhIL-3), rhGM-CSF, and rhIL-5. Messenger RNAs encoding eosinophil peroxidase (EPO), major basic protein (MBP), eosinophil-derived neurotoxin (EDN), and eosinophil cationic protein (ECP) were detected by Northern blot hybridization with the respective specific oligonucleotide probes. In mature PBE, MBP mRNA appeared to be absent, whereas EPO mRNA was barely detectable in only 5 of the 19 patients. In contrast, EDN and ECP mRNAs were observed in the PBE of all patients. In CE, EPO, and MBP, mRNAs were abundant in immature eosinophils and their amounts decreased after differentiation toward eosinophils. ECP and EDN mRNAs followed the same patterns, but mRNAs were less abundant at all timepoints studied. Study of mRNA t1/2 during the time course of differentiation indicated that changes in the stability of the different mRNAs were not responsible for the variations observed in the steady-state levels. Together, these results suggest that regulation of expression differs among EPO, MBP, EDN, and ECP mRNAs during the time course of eosinophil differentiation.

T cell receptor V beta variable gene family expression in human peripheral blood lymphocytes at the mRNA and membrane protein level

A polymerase chain reaction (PCR) was developed, using combinations of an oligonucleotide primer for a T cell receptor V beta gene family and one for the constant C beta gene segments, to assess the expression of each of 20 V beta gene families in RNA after reverse transcription into cDNA. The detection was done after agarose gel electrophoresis of PCR products and ethidium bromide staining. The positive identification of the PCR products was done by hybridization with a J beta oligonucleotide probe. For T cell lines, a signal was observed in the V beta 8 combination for Jurkat cells, V beta 5a in HSB cells, V beta 2 and V beta 12a in Molt-3 cells and V beta 2, V beta 5a and V beta 12a in Molt-4 cells. Using mixtures of RNA from different cell lines, the sensitivity of the method was in the range of 0.1-0.5%. In peripheral blood mononuclear cells from four donors, taken at three different occasions, all V beta families were detectable. The intensity of the PCR product varied between various V beta gene families. Flow cytometric analysis of blood mononuclear cells from the same donors with a restricted series of V beta gene family-specific antibodies also revealed the presence of all families. The approach to assess V beta gene family expression in heterogeneous populations opens the possibility to study T cell receptor variable gene expression in relation to physiology and pathologic processes.

Dried blood spot on filter paper as a source of mRNA

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