Molecular cloning and functional expression of mouse cDNAs encoding the membrane receptor and the soluble receptor for D-factor/LIF.
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Biomedical subjects
Publications and source records attributed to M Tomida.
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Differentiation-stimulating factor (D-factor)/leukemia inhibitory factor can induce the differentiation of mouse myeloid leukemia M1 cells and also stimulate proliferation of the interleukin-3 (IL-3)-dependent cell line, DA-1a. To determine whether D-factor can induce the differentiation of leukemia cells other than M1 cells, WEHI-3B D+ mouse myelomonocytic leukemia cells were transfected with a plasmid containing mouse D-factor receptor cDNA. Expression of D-factor receptor in transfected cells was determined by binding of [125]D-factor and analyzed by Scatchard's method. The transfected cells had high-affinity D-factor receptors with a dissociation constant of 100 to 200 pmol/L and binding sites per cell varied from 67 to 1,500 among several clones. The cells expressing a high level of D-factor receptor were induced to differentiate by D-factor; about 60% of the cells exhibited the ability to reduce nitroblue tetrazolium and expression of the differentiation antigen Mac-1 (CD11b) on the cell surface increased. The effect of cytokines, which induce the differentiation of M1 cells, on the transfected WEHI-3B cells was examined. The sensitivity to oncostatin M was identical to that against D-factor in the cells of each clone. Expression of D-factor receptor in WEHI-3B cells promoted sensitivity to IL-6 and granulocyte colony-stimulating factor (G-CSF). Induction of differentiation of the cells accompanied the suppression of proliferation. Treatment of the cells with D-factor for longer than 5 days resulted in 50% inhibition of growth. These results indicate that the stimulating effect of D-factor on the differentiation of malignant myeloid cells is not unique to M1 cells.
We have examined molecular properties of inhibitor-complexed human and bovine band 3, an anion transport protein of erythrocyte membrane, in order to demonstrate the structural characteristics of the inhibitor binding region. Band 3 modified with DIDS (4,4'-diisothiocyano-2,2'-stilbenedisulfonate), a potent anion transport inhibitor, generated a positive circular dichroic band at a wavelength of 345 nm, corresponding to a DIDS chromophore. The dichroic spectra of human band 3-DIDS complex and its bovine counterpart differed markedly in their ellipticity. Under the conditions that H2DIDS (the dihydro-derivative of DIDS) cross-linked two chymotryptic fragments of human band 3, the reagent failed to cross-link the equivalent bovine fragments. The inhibitory effect of PLP (pyridoxal 5'-phosphate), a substrate and affinity label, on phosphate influx into red blood cells was more pronounced for human band 3 than for bovine band 3. The residue Lys-562 of human band 3 was found to be modified with PLP, while the corresponding residue of bovine band 3 was devoid of reactivity with PLP.
The recombinant soluble mouse D-factor/LIF receptor (sD-factor-R) was expressed in COS-7 cells. Scatchard analysis of the bindings of mouse 125I-D-factor and human 125I-D-factor to the sD-factor-R indicated dissociation constants (Kd) of 12 and 0.267 nM, respectively, which were comparable to those of the binding protein in mouse serum. The apparent molecular masses of the sD-factor-R and human D-factor observed by gel filtration chromatography were 150 and 50 kDa, respectively. The size of the sD-factor-R.human D-factor complex was approximately 200 kDa, indicating that D-factor forms a 1:1 complex with the sD-factor-R. The sD-factor-R inhibited the induction of differentiation of mouse myeloid leukemic M1 cells by mouse D-factor by blocking the binding of this factor to the cells.
Three cDNAs for mouse differentiation-stimulating factor (D-factor)/leukemia inhibitory factor (LIF) receptor were isolated from a cDNA library prepared from the liver of a pregnant mouse. A probe for screening was prepared by the RT-PCR method using human cDNA sequences as primers. The mouse D-factor receptor cDNA encoded 1,092 amino acids, which had a marked homology with the human counterpart and consisted of signal sequence, extracellular, transmembrane, and cytoplasmic domains. The WSXWS motif found in members of the cytokine receptor family was also present in the extracellular domain of the mouse D-factor receptor. A second form of cDNA that had a 501 bp insertion was isolated. The insertion introduced a stop codon so that the mRNA encoded the soluble receptor lacking transmembrane and intracellular domains. Because the insertion contained polyadenylation signals, two different sizes of mRNA encoding the soluble receptor were produced, depending on whether or not it utilized these signals. Transcripts utilizing these signals were 2.6-3 kb in size, and were very abundantly expressed in the liver. Transcripts that did not use these signals were longer than 5 kb and of similar size to the mRNA for the cellular receptor.
A 35-year-female developed tetraparesis following a period of back pain, urinary retension and paraparesis. She was admitted to our hospital on September 22, 1990. Neurological examination revealed tetraparesis with a sensory level at C3. Deep tendon reflexes were hyperactive in all four extremities with bilateral Hoffmann and Babinski reflexes. Spinal MR imaging demonstrated cavity formation within the cervical cord, extending from C2 to C6 without any anomalies at the craniocervical junction including Chiari malformation. The cavity was not enhanced with Gd-DTPA. Cerebrospinal fluid (CSF) examination revealed no abnormality. Although a syringo-subarachnoid shunt was performed on October 18, 1990, her symptoms did not improve. On December 17, 1990, she developed optic neuritis in the right eye and her paraparesis deteriorated. Delayed metrizamide CT scans showed another syrinx from Th3 to Th9. Repeated CSF contained 37 cells/mm3, protein 88 mg% and sugar 49 mg%. CSF oligoclonal bands were present and the CSF myelin basic protein was 6.6 ng/ml (normal < 4). A pulse therapy of steroid improved her vision and paraparesis. However, she developed paraparesis again on October 29, 1991. A brain T2-weighted MR image demonstrated multiple periventricular high signal intensity spots. Her paraparesis improved again with steroid. MR images in September, 1992 revealed a cord atrophy and disappearance of the cavity. Based on these clinical courses and radiological findings, a definite diagnosis of multiple sclerosis (MS) was made. We think MS may have caused the syringomyelia.
We examined the distribution of mRNAs for differentiation-stimulating factor (D-factor)/leukemia inhibitory factor (LIF) receptor in various mouse tissues by Northern blotting. A mouse cDNA fragment encoding the D-factor receptor was prepared by the RT-PCR method using human cDNA sequences as primers. The smallest mRNA (3 kb) was present in the liver, but not detectable in other tissues examined. Larger mRNAs (5 and 10 kb) were present in the placenta and the M1 cells, and also detectable in the liver, kidney, heart, lung, brain and embryos. Expression of 3 kb mRNA in the liver increased during pregnancy, being 20 times the initial level on day 15. D-factor receptor cDNAs were isolated from a cDNA library prepared from the liver of a pregnant mouse. Most of the cDNA clones encoded a soluble receptor. A cDNA probe specific for the cellular receptor did not hybridize with 3 kb mRNA in the liver. These results suggest that 3 kb mRNA encodes a soluble D-factor receptor and that the liver is the primary site of synthesis of this soluble receptor.
Differentiation-stimulating factor (D-factor)/leukemia inhibitory factor (LIF) is known to have multiple biological activities besides induction of differentiation of mouse myeloid leukemia M1 cells. Little is known about how its activities are regulated in vivo, but it has been suggested to play a regulatory role in the mechanisms involved in development of mice. In this study, we found that a single class of D-factor-binding substance is present in normal mouse serum and that it increases transiently in the late stage of pregnancy. It inhibits the induction of differentiation of mouse myeloid leukemic M1 cells by D-factor by blocking the binding of this factor to the cells. It is a heat-labile protein with an apparent molecular weight of 130,000-150,000. The binding of 125I-D-factor to the substance is specific since it was inhibited by excess unlabeled D-factor, but not by interleukin 6 or interferon gamma. The dissociation constant of the binding substance for mouse D-factor in normal mouse serum is 6.6-9.4 nM. In the late stage of pregnancy, the amount of the D-factor-binding substance in the serum apparently increases about 30-fold. These results suggest that the D-factor-binding substance regulates the activity of D-factor during embryonic development of mice.
Leukemia inhibitory factor/differentiation-stimulating factor (LIF/D-factor), expression of its mRNA, and possible roles in bone metabolism were studied in murine primary and clonal osteoblast-like cells. Local bone-resorbing factors such as IL-1, TNF alpha, and LPS strongly induced expression of LIF/D-factor mRNA in both clonal MC3T3-E1 cells and primary osteoblast-like cells. Neither parathyroid hormone nor 1 alpha,25-dihydroxyvitamin D3 stimulated expression of LIF/D-factor mRNA. LIF/D-factor per se did not stimulate expression of its own mRNA. Appreciable amounts of LIF/D-factor were detected in synovial fluids from rheumatoid arthritis (RA) patients but not in those with osteoarthritis (OA). Simultaneous treatment with LIF/D-factor, IL-1, and IL-6 at the concentrations found in synovial fluids from RA patients greatly enhanced bone resorption, though these cytokines did not stimulate bone resorption when separately applied. This suggests that LIF/D-factor produced by osteoblasts is in concert with other bone-resorbing cytokines such as IL-1 and IL-6 involved in the bone resorption seen in the joints of RA patients. LIF/D-factor specifically bound to MC3T3-E1 cells with an apparent dissociation constant of 161 pM and 1,100 binding sites/cell. LIF/D-factor dose-dependently suppressed incorporation of [3H]thymidine into MC3T3-E1 cells. In addition, it potentiated the alkaline phosphatase activity induced by retinoic acid, though LIF/D-factor alone had no effect on enzyme activity. These results suggest that LIF/D-factor is involved in not only osteoclastic bone resorption but also osteoblast differentiation in conjugation with other osteotropic factors.
Mouse myeloid leukemic M1 cells can be induced to differentiate into macrophages by differentiation-stimulating factor (D-factor)/leukemia inhibitory factor (LIF). We examined the effect of D-factor on the survival times of syngeneic mice implanted with two different clones (T-22 and R-4) of M1 cells. D-factor induced differentiation and suppressed DNA synthesis of sensitive T-22 cells but not resistant R-4 cells in vitro. For in vivo experiments, we used recombinant mouse D-factor (rmD-factor) produced in mammalian cells, which is glycosylated and is more stable in vitro and in vivo than unglycosylated rmD-factor produced in Escherichia coli. Treatment with rmD-factor prolonged the survival times of mice implanted with T-22 cells but not R-4 cells.
We studied the effects of D-factor on the growth of leukemic blast progenitors from 15 patients with acute myeloblastic leukemia and two leukemia cell lines in methylcellulose and suspension cultures. When stimulated by granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor or interleukin-3, leukemic blast progenitors undergo terminal division with limited differentiation in methylcellulose culture, forming blast colonies. Leukemic blast progenitors can renew themselves. The self-renewal can be detected as secondary colony formation after replating primary blast colonies in fresh methylcellulose media and by the growth of clonogenic cells in suspension culture. D-Factor suppressed primary and secondary colony formation in methylcellulose culture. Furthermore, D-factor suppressed clonogenic cell recovery in suspension culture. The suppression by D-factor of the growth of leukemic blast progenitors was not significantly dependent upon the colony-stimulating factors used as growth-stimulating factors. High concentration of G-CSF did not overcome the suppressive effect of D-factor. The results indicate that D-factor is effective in suppressing not only terminal division but also self-renewal of leukemic blast progenitors.
Differentiation-stimulating factor (D-factor)/leukemia inhibitory factor (LIF) is a cytokine inducing differentiation of mouse myeloid leukemic M1 cells. IL-6, oncostatin M (OSM) and G-CSF also induce differentiation of M1 cells. These four cytokines are suggested to be members of a single cytokine family. The LIF receptor is structurally related to the gp130 signal-transducing component of the IL-6 receptor and to the G-CSF receptor. The high-affinity receptors for LIF, OSM and IL-6 share the common subunit, gp130. This provides an explanation for the functional redundancy of those cytokines.
Differentiation-stimulating factor (D factor)/leukemia inhibitory factor (LIF) and IL-6 are reported to be cytokines having multifaced functions including the induction of differentiation in mouse myeloid leukemia M1 cells. We here report that both D factor/LIF and IL-6 inhibit the differentiation of mouse teratocarcinoma F9 cells induced by retinoic acid alone or combined with dibutyryl cAMP. From the microscopic observation as well as Northern blot analysis using cDNA probes encoding several marker proteins for differentiation of F9 cells, we concluded that D factor/LIF and IL-6 are functionally closely related in the induction of differentiation in M1 cells and in the inhibition of F9 differentiation.
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Differentiation-stimulating factor (D-factor)/leukemia inhibitory factor is a cytokine inducing differentiation of mouse myeloid leukemic M1-T22 cells. The effect of recombinant human D-factor on growth and differentiation of pig kidney LLC-PK1 cells was examined. LLC-PK1 cells did not concentrate alpha-methylglucoside during their early growth in culture but developed the capacity to concentrate this hexose as they reached confluence and their growth rate decreased. Purified D-factor caused dose-dependent inhibition of the development of this concentrative capacity. It did not affect the growth rate of the cells, but inhibited the formation of multicellular domes in confluent cultures. LLC-PK1 cells were found to have high-affinity binding sites (831 per cell) for D-factor with a dissociation constant of 197 pM.
We have purified and characterized several protein factors that regulate the growth and differentiation of mouse myeloid leukaemia M1 cells. The differentiation factor (D-factor) from conditioned medium (CM) of Ehrlich ascites tumour cells is a glycoprotein of Mr 40,000-50,000. Its amino acid sequence was found to be almost identical to that of leukaemia inhibitory factor (LIF) from Krebs II ascites cells. The differentiation inhibitory factor (I-factor) from the CM of variant M1 cell clones which were resistant to several differentiation inducers is a basic protein of apparent Mr 68,000. The growth inhibitory factor (GI-factor) that specifically inhibits the partially differentiated and still growing monocytic leukaemia M1 cells was isolated from the CM of a clone of M1 cells resistant to the differentiation inducers. This GI-factor is a basic protein with an Mr of 25,000. Regulation by these protein factors together with other known cytokines of growth and differentiation of M1 cells is reported.
We have studied the production of interleukin 6 (IL-6) and its relation to the macrophage differentiation in murine myeloid leukemia cells (M1). As has been reported, differentiation-inducing factor (D-factor), 1 alpha, 25-dihydroxyvitamin D3 [1 alpha, 25(OH)2D3], and recombinant IL-6 similarly induced differentiation of M1 cells into macrophages. The three compounds also induced mRNA expression of IL-6 in M1 cells. M1 cells treated with D-factor or 1 alpha, 25(OH)2D3 produced biologically active IL-6, but the amounts of IL-6 secreted into culture media did not appear to be enough to induce differentiation of M1 cells. Furthermore, simultaneous addition of anti-IL-6 antibody did not suppress the differentiation of M1 cells induced by D-factor or 1 alpha, 25(OH)2D3. These results show that IL-6 production is an essential property associated with the macrophage differentiation of M1 cells, but it may not be responsible for the D-factor- and 1 alpha, 25(OH)2D3-induced differentiation.