Developmental changes in multispecific organic anion transporter 1 expression in the rat kidney

BACKGROUND

The cDNA of the multispecific organic anion transporter 1 (OAT1) responsible for the tubular secretion of organic anions was recently isolated. In the current study, we investigated the developmental changes in OAT1 expression in the rat kidney.

METHODS

Ontogenic expression of rat OAT1 was investigated by Northern blot, in situ hybridization, Western blot, and immunohistochemical analysis. In addition, para-aminohippurate (PAH) accumulation was measured using fetal, neonatal, and adult rat kidney slices.

RESULTS

In Northern blot analysis, OAT1 was detected as early as on embryonic day 18 in the fetal kidney. The expression level of OAT1 mRNA increased remarkably just after birth (postnatal day 0). In situ hybridization revealed OAT1 expression on embryonic day 19. In both the fetal and neonatal kidneys, OAT1 mRNA was localized in a relatively deep region in the cortex. Western blot analysis detected OAT1 protein on embryonic day 20, and the expression level increased after birth. Immunohistochemical analysis did not reveal OAT1 staining in the fetal kidneys. A faint signal of OAT1 protein was detected on postnatal day 0; thereafter, the expression level increased. In the functional study using kidney slices, low but definite probenecid-sensitive PAH accumulation was noted in fetal rat kidney on embryonic day 20. After birth, probenecid-sensitive PAH uptake was increased.

CONCLUSIONS

The present study consistently demonstrates the remarkable increase of OAT1 expression after birth, and the immature excretory capacity of the proximal tubules of the neonatal kidney can be attributed, at least in part, to the low expression level of OAT1.

The effect of granulocyte colony-stimulating factor administration in healthy donors before bone marrow harvesting

To investigate whether granulocyte colony-stimulating factor (G-CSF) administration to donors before harvest may lighten the burden imposed on them and accelerate the bone marrow (BM) recovery, we administered 2 microgram/kg/d of G-CSF for five consecutive days before the marrow harvest. All of the donors tolerated the G-CSF administration well without severe adverse events. After 5 d of G-CSF treatment, CD34+ cells and granulocyte-macrophage colony-forming units (GM-CFU) in the donors' BM exceeded baseline values by 4.2-fold (range 0.71-316) and 1.6-fold (0.28-118) respectively. The concentration of total nucleated cells (x 107/ml) in the graft increased from 1.61 (0.95-3.23) to 2.44 (1.27-4.01). Although we collected 1020 ml of BM and obtained 1.50 x 1010 nucleated cells from unprimed donors, 940 ml of BM were sufficient to obtain 2.14 x 1010 nucleated cells from primed donors. However, G-CSF-primed BM did not shorten the time to tri-lineage engraftment and the duration of hospitalization compared with unprimed BM, although primed BM contained more CD34+ cells than baseline values. We consider that the advantages of BM priming are not the acceleration of BM recovery but rather the reduction of blood loss during BM harvesting.

Effects of tetrahydrobiopterin on endothelial dysfunction in rats with ischemic acute renal failure

The role of nitric oxide (NO) in ischemic renal injury is still controversial. NO release was measured in rat kidneys subjected to ischemia and reperfusion to determine whether (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4), a cofactor of NO synthase (NOS), reduces ischemic injury. Twenty-four hours after bilateral renal arterial clamp for 45 min, acetylcholine-induced vasorelaxation and NO release were reduced and renal excretory function was impaired in Wistar rats. Administration of BH4 (20 mg/kg, by mouth) before clamping resulted in a marked improvement of those parameters (10(-8) M acetylcholine, delta renal perfusion pressure: sham-operated control -45 +/- 5, ischemia -30 +/- 2, ischemia + BH4 -43 +/- 4%; delta NO: control +30 +/- 6, ischemia + 10 +/- 2, ischemia + BH4 +23 +/- 4 fmol/min per g kidney; serum creatinine: control 23 +/- 2, ischemia 150 +/- 27, ischemia + BH4 48 +/- 6 microM; mean +/- SEM). Most of renal NOS activity was calcium-dependent, and its activity decreased in the ischemic kidney. However, it was restored by BH4 (control 5.0 +/- 0.9, ischemia 2.2 +/- 0.4, ischemia + BH4 4.3 +/- 1.2 pmol/min per mg protein). Immunoblot after low-temperature sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the dimeric form of endothelial NOS decreased in the ischemic kidney and that it was restored by BH4. These results suggest that the decreased activity of endothelium-derived NO may worsen the ischemic tissue injury, in which depletion of BH4 may be involved.

Identification of a melanoma antigen, PRAME, as a BCR/ABL-inducible gene

In order to elucidate molecular events in BCR/ABL-induced transformation, we adopted a polymerase chain reaction (PCR)-based technique of differential display and compared mRNA expression in human factor-dependent cells, TF-1, with that in factor-independent cells, ID-1, which were established from TF-1 cells by transfection of BCR/ABL. Cloning and sequencing of a gene which was upregulated in ID-1 cells revealed that the gene was identical to a melanoma antigen, PRAME. Our present study demonstrated that PRAME was markedly expressed in primary leukemic cells with chronic myeloid leukemia (CML) in blastic crisis and Philadelphia (Ph)+-acute lymphoblastic leukemia (ALL), in which BCR/ABL played an important role as a pathogenic gene. Moreover, comparison of PRAME expression among CD34+ cells with CML in blastic, accelerated, and chronic phases revealed a higher expression in CML in advanced phases. Thus PRAME was considered to be a good candidate for a marker of Ph+-leukemic blast cells as well as a new target antigen of leukemic blast cells that cytotoxic T cells can recognize.

Biological activity of human granulocyte colony stimulating factor with a modified C-terminus

Granulocyte colony-stimulating factor (G-CSF) undergoes receptor-mediated internalization into target cells which are normally restricted to neutrophilic granulocytes and their committed progenitor cells, suggesting that it may be applicable as a myeloid cell-targeting vehicle. To test this notion, we constructed a cDNA encoding a human G-CSF/murine stem cell factor (mSCF) chimeric molecule in a mammalian expression vector and transfected NIH3T3 cells with this plasmid. The resulting chimeric cytokine consisted of the entire G-CSF sequences fused to Lys148 of mSCF. It can be released from the surface membrane of NIH3T3 transformants through proteolytic cleavage at Ala164 of mSCF. The culture media conditioned by a number of stable transformants, which were confirmed by an enzyme-linked immunosorbent assay (ELISA) to secrete an hG-CSF derivative, were examined for their ability to stimulate CFU-G-derived colony formation as well as the proliferation of G-CSF-dependent NFS-60 cells. The results indicated that this C-terminus modified version of hG-CSF is as potent as recombinant hG-CSF in both assays.

Role of organic anion transporter 1 (OAT1) in cephaloridine (CER)-induced nephrotoxicity

Role of organic anion transporter 1 (OAT1) in cephaloridine (CER)-induced nephrotoxicity.

BACKGROUND

Cephaloridine (CER) has been used to elucidate the mechanisms of cephalosporin antibiotic-induced nephrotoxicity. Organic anion transporters have been thought to mediate CER uptake by the proximal tubule. The purpose of this study was to elucidate the possible involvement of organic anion transporter 1 (OAT1) in CER-induced nephrotoxicity.

METHODS

A mouse terminal proximal straight tubule (S3) cell line stably expressing rat OAT1 (S3 rOAT1) was established and used in this study. The cellular uptake of [14C]-para-aminohippuric acid (PAH), a prototype organic anion, and that of [14C]-CER were measured. The effects of CER on the viability of the cells and the amount of lipid peroxidation were estimated.

RESULTS

S3 rOAT1 expressed a functional organic anion transporter in the cytoplasmic membrane, and exhibited CER uptake activity. CER treatment resulted in a more significant decrease in the viability and a more significant increase in the amount of lipid peroxidation in S3 rOAT1 than in S3 cells transfected with an expression vector lacking the rOAT1 insert. Probenecid, an inhibitor of organic anion transport, and probucol, an antioxidant, significantly suppressed the decrease in viability and increase in the amount of lipid peroxidation in S3 rOAT1 treated with CER. The effects of various cephalosporin antibiotics on the uptake of [14C]PAH were correlated significantly with the effects of these drugs on cell viability.

CONCLUSIONS

These results suggest that rOAT1 is, at least in part, responsible for the cellular uptake of CER and therefore CER-induced nephrotoxicity.

Regulation by 1alpha,25-dihydroxyvitamin D(3) of expression of stanniocalcin messages in the rat kidney and ovary

Regulation by vitamin D(3) of expression of the genes for stanniocalcins 1 and 2 (STC-1 and STC-2) was studied and their levels were shown to be oppositely regulated in the kidney and to remain unaffected in the ovary. Female rats were treated with calcitriol, the active form of vitamin D(3), and alterations in the levels of STC-1 and STC-2 mRNA were determined by Northern blot analysis in the kidney and ovary where the STC-1-expressing cells have previously been identified by in situ hybridization histochemistry. In the kidney, calcitriol treatment increased the STC-1 mRNA levels more than 3-fold, but decreased the STC-2 message to trace levels. In the ovary, however, both STC-1 and STC-2 mRNA levels were not significantly affected by the calcitriol treatment. These results support the hypotheses that (1) STC-1 and STC-2 have opposite effects on calcium and phosphate homeostasis, namely anti-hypercalcemic and anti-hypocalcemic actions, respectively, and (2) the mammalian stanniocalcin system acquired, in addition to the role in the systemic mineral metabolism, a role in the reproduction system that operates independently of the systemic condition.

Effects of amlodipine on nitric oxide synthase mRNA expression and coronary microcirculation in prolonged nitric oxide blockade-induced hypertensive rats

We evaluated the effects of long-term treatment with amlodipine, a calcium antagonist, on nitric oxide synthase (NOS) activity and NOS messenger RNA (mRNA) expression in the left ventricle (LV) and its relation to coronary reserve, and microvascular remodeling in Nomega-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats. Seventeen male Sprague-Dawley rats were given L-NAME (60 mg/kg/day) in drinking water for 6 weeks to induce hypertension, and then treated with amlodipine (L-NAME + A, 5 mg/kg/day, n = 9), or a vehicle (L-NAME + V, n = 8) for 4 weeks. Age-matched rats (C, n = 8) served as the control group. An increased blood pressure in L-NAME + V was significantly decreased in L-NAME + A. Nitrite production and endothelial cell (e) NOS mRNA in the LV were significantly decreased in L-NAME + V compared with C, and were significantly increased in L-NAME + A compared with C and L-NAME + V. L-NAME + V had a significantly decreased coronary reserve and capillary density, and a significantly increased type I collagen mRNA expression, wall-to-lumen ratio, perivascular fibrosis, myocardial fibrosis, and myocyte cross-sectional area. These parameters in the microvasculature were significantly improved by amlodipine. We concluded that NOS activity and eNOS mRNA were significantly increased by amlodipine in the LV of L-NAME-induced hypertensive rats, and that these increase NOS activity and eNOS mRNA expression may play a role in the amelioration of coronary reserve and microvascular remodeling.

Nitric oxide synthase in the JGA of the SHR: expression and role in tubuloglomerular feedback

The spontaneously hypertensive rat (SHR) has an enhanced tubuloglomerular feedback (TGF) and a diminished buffering by juxtaglomerular apparatus (JGA)-derived NO. We examined the hypothesis that these effects are due to decreases in nitric oxide synthase (NOS) expression or limited availability of L-arginine or tetrahydrobiopterin (BH(4)). SHR had significantly (P < 0.05) greater mRNA abundance (by RT-PCR) or protein (by Western analysis) for neuronal NOS (nNOS, or type I) and endothelial cell NOS (ecNOS, or type III) in renal cortex or isolated glomeruli, respectively. There was prominent expression of ecNOS in glomerular endothelium and nNOS in macula densa. Maximal TGF responses, assessed from changes in proximal stop-flow pressure during orthograde loop of Henle (LH) perfusion, were greater in SHR [Wistar-Kyoto (WKY), 8.1 +/- 0.3 (n = 46) vs. SHR, 10.3 +/- 0.3 mmHg (n = 57); P < 0.001]. Unlike WKY, TGF responses of SHR were unresponsive to microperfusion of the nNOS inhibitor, 7-nitroindazole (7-NI, 10(-4) M) [WKY, 9.5 +/- 0.5 to 13.2 +/- 0.7 (n = 13, P < 0.001) vs. SHR, 11.8 +/- 0.7 to 12.5 +/- 0.6 mmHg (n = 19, not significant)], or to L-arginine (10(-3) M) [WKY, 7.7 +/- 0.8 to 6.3 +/- 0.4 (n = 10, P < 0.05) vs. SHR, 10.4 +/- 0.7 to 10.6 +/- 0.7 mmHg (n = 10, not significant)]. Neither BH(4) (10(-4) M) nor sepiapterin (10(-4) M), its stable precursor, modified TGF responses in WKY or in SHR, nor did they restore a response to microperfusion of 7-NI in SHR. In conclusion, there is a diminished role for NO from nNOS in blunting of TGF in SHR which cannot be ascribed to limited NOS expression or availability of substrate or BH(4).

The common marmoset as a target preclinical primate model for cytokine and gene therapy studies

Nonhuman primate models are useful to evaluate the safety and efficacy of new therapeutic modalities, including gene therapy, before the inititation of clinical trials in humans. With the aim of establishing safe and effective approaches to therapeutic gene transfer, we have been focusing on a small New World monkey, the common marmoset, as a target preclinical model. This animal is relatively inexpensive and easy to breed in limited space. First, we characterized marmoset blood and bone marrow progenitor cells (BMPCs) and showed that human cytokines were effective to maintain and stimulate in culture. We then examined their susceptibility to transduction by retroviral vectors. In a mixed culture system containing both marmoset stromal cells and retroviral producer cells, the transduction efficiency into BMPCs and peripheral blood progenitor cells (PBPCs) was 12% to 24%. A series of marmosets then underwent transplantation with autologous PBPCs transduced with a retroviral vector carrying the multidrug resistance 1 gene (MDR1) and were followed for the persistence of these cells in vivo. Proviral DNA was detectable by polymerase chain reaction (PCR) in peripheral blood granulocytes and lymphocytes in the recipients of gene transduced progenitors up to 400 days posttransplantation. To examine the function of the MDR1 gene in vivo, recipient maromsets were challenged with docetaxel, an MDR effluxed drug, yet the overall level of gene transfer attained in vivo (<1% in peripheral blood granulocytes) was not sufficient to prevent the neutropenia induced by docetaxel treatment. Using this model, we safely and easily performed a series of in vivo studies in our small animal center. Our results show that this small nonhuman primate, the common marmoset, is a useful model for the evaluation of gene transfer methods targeting hematopoietic stem cells.

Distribution of postsynaptic density proteins in rat kidney: relationship to neuronal nitric oxide synthase

BACKGROUND

Neuronal nitric oxide synthase (nNOS) is expressed in skeletal muscle beneath the sarcolemma associated with dystrophin complex. In brain, nNOS is anchored to synaptic membranes by specific postsynaptic density proteins (PSD)-95 and PSD-93. We have investigated the cellular and subcellular localization of these PSD proteins in the kidney and their relationship to nNOS and the cell membrane.

METHODS

Kidneys from male Sprague-Dawley rats were processed for light and electron microscopic immunohistochemistry with polyclonal antibodies against PSD and nNOS proteins.

RESULTS

Western blot analysis of rat kidney revealed a specific band for PSD-93 at the molecular weight of 103 kDa. Immunostaining for PSD-93 was located in the thick ascending limb of the loop of Henle, macula densa cells, distal convoluted tubules, cortical collecting ducts, outer and inner medullary collecting duct, glomerular epithelium, and Bowman's capsule. A pre-embedding electron microscopic immunoperoxidase procedure localized PSD-93 to the basolateral membrane of these tubular cells. Using different sized immunogold particles, a portion of nNOS in the macula densa colocalized with PSD-93 adjacent to cytoplasmic vesicles and the basolateral membrane. In contrast, PSD-95 protein was detected only weakly in the cortex by Western blot. Immunostaining for PSD-95 was located only faintly in the apical membrane of the thick ascending limb, macula densa, distal convoluted tubule and cortical collecting duct cells.

CONCLUSION

PSD-93 is the predominant PSD expressed in the rat kidney. It is located primarily in the basolateral membranes of distal nephron and colocalizes with a pool of nNOS in cytoplasmic vesicles and basolateral membranes of macula densa cells.

Effects of hypertension, diabetes mellitus, and hypercholesterolemia on endothelin type B receptor-mediated nitric oxide release from rat kidney

BACKGROUND

Although endothelin-1 is a potent vasoconstrictor peptide, stimulation of endothelin type B receptor (ETBR) causes bidirectional changes in vascular tone, ie, vasodilation and vasoconstriction. Roles of ETBR in pathological conditions are largely unknown.

METHODS AND RESULTS

We studied the effect of BQ-3020, a highly selective ETBR agonist, on renal vascular resistance and nitric oxide (NO) release in the isolated, perfused kidney of rats with hypertension, diabetes mellitus, and hypercholesterolemia. Immunohistochemistry of endothelial NO synthase and ETBR was also examined. Infusion of BQ-3020 at concentrations of </=10(-10) mol/L reduced renal perfusion pressure in Dahl salt-resistant (R) rats but increased renal perfusion pressure in Dahl salt-sensitive (S) rats (10(-10) mol/L: -10.3+/-0. 6% versus 11.2+/-1.5%, R versus S; P<0.01). BQ-3020 caused a dose-dependent release of NO in both R and S rats, although the level of NO release in S rats was lower, as detected by chemiluminescence (10(-10) mol/L: 10.7+/-0.7 versus 3.1+/-0.4 fmol/min per gram of kidney, R versus S; P<0.01). Similar effects of BQ-3020 were observed in streptozotocin-induced diabetic rats and diet-induced hypercholesterolemic rats. Expression of endothelial NO synthase decreased in S rats but not in diabetic or hypercholesterolemic rats. In contrast, expression of ETBR in the endothelium was decreased in all 3 disease models compared with that in the vascular smooth muscle cell.

CONCLUSIONS

These results suggest that impaired NO release in response to stimulation of ETBR is due, at least in part, to a decrease in endothelial ETBR and may play a role in vascular dysfunction usually associated with arteriosclerosis-related diseases.

Immunohistochemical localization of multispecific renal organic anion transporter 1 in rat kidney

Renal proximal convoluted tubules have an important role, i.e., to excrete organic anions, including numerous drugs and endogenous substances. Recently, multispecific organic anion transporter 1 (OAT1) was isolated from rat kidney. In this study, the cellular and subcellular localization of OAT1 in rat kidney was investigated. Kidneys from normal rats were perfused and fixed with periodate-lysine-paraformaldehyde solution and were then processed for immunohistochemical analysis using the labeled streptavidin-biotin method, preembedding horseradish peroxidase method, and immunogold method. Light microscopic examination revealed immunostaining for OAT1 in the middle portion of the proximal tubule (S2 segment), but not in the initial portion of the proximal convoluted tubule, next to the glomerulus. Nephron segments other than the S2 segment and the renal vasculature were not stained with antibody to OAT1. Electron-microscopic observation using a preembedding method revealed that OAT1 was exclusively expressed in the basolateral membrane of S2 segments of proximal tubules. The immunogold method showed no labeling for OAT1 in the cytoplasmic vesicles, suggesting that OAT1 may not move together with organic anions into the cells. These results are consistent with previous physiologic data showing that organic anions, including para-aminohippurate, are taken up by the basolateral Na+-independent organic anion/dicarboxylate exchanger and excreted at S2 segments. In conclusion, OAT1 was localized to the basolateral membrane of S2 segments of proximal tubules in rat kidneys.

Fusion of ETV6 to neurotrophin-3 receptor TRKC in acute myeloid leukemia with t(12;15)(p13;q25)

Chromosome translocations involving band 12p13 are known to be involved in a variety of hematologic malignancies, some of them resulting in rearrangement of the ETV6/TEL gene. Applying the fluorescence in situ hybridization (FISH) method, we found a cryptic translocation t(12;15)(p13;q25) in an adult acute myeloid leukemia (AML) patient. Hybridization with cosmid probes showed that the ETV6 gene was rearranged in this translocation. A patient-specific cDNA library was screened with ETV6 cDNA, and a novel fusion transcript was identified between the ETV6 and TRKC/NTRK3 gene located on 15q25. TRKC is a receptor tyrosine kinase that is activated by neurotrophin-3 (NT-3). It is known to be expressed broadly in neural tissues but not in hematologic cells, so far. ETV6-TRKC chimeric transcript encoded the pointed (PNT) domain of the ETV6 gene that fused to the protein-tyrosine kinase (PTK) domain of the TRKC gene. Two types of fusion transcript were determined, one that included the entire PTK domain of TRKC and the other in which the 3'-terminal 462 bp of TRKC was truncated within the PTK domain. Western blot analysis showed the expression of both chimeric proteins of 52 and 38 kD in size. Our results suggest that chimeric PTK expressed in the leukemic cells may contribute to cellular transformation by abnormally activating TRK signaling pathways. Moreover, this is the first report on truncated neurotrophin receptors associated in leukemia.

CD4/CD8 double-positive adult T cell leukemia with preceding cytomegaloviral gastroenterocolitis

We present a rare case of adult T cell leukemia (ATL) in which leukemic T cells simultaneously expressed CD4 and CD8 surface antigens and refractory cytomegalovirus (CMV)-induced gastroenterocolitis preceded its clinical onset. A 40-year-old male was admitted to our hospital with abdominal pain and bloody stool. Biopsy specimens of the gastric and rectal mucosa indicated CMV-induced gastroenterocolitis. The patient also proved to be seropositive for human T lymphotropic virus type I (HTLV-I). While being administered gancyclovir for CMV infection, he presented hepatomegaly and systemic lymphadenopathy. Monoclonal expansion of lymphoid cells integrated with HTLV-I genome was observed. He underwent a LSG15 regimen and hepatomegaly and lymphadenopathy improved markedly. Gastroenterocolitis also improved, but the symptoms did not disappear completely. CMV-induced diseases are prevalent among immunosuppressed patients. Although there was no evidence that this patient had ATL on admission, it is likely that he was severely immunodeficient. CMV can easily infect damaged mucosa. ATL cells often infiltrate gastrointestinal mucosa and may have triggered CMV gastroenterocolitis in this case.

Significant expression of G-CSF-induced gene-1 (GIG-1) protein in myeloid cells and NK cells

The granulocyte colony-stimulating factor (G-CSF)-induced gene, GIG-1, was originally cloned from G-CSF-stimulated bone marrow mononuclear cells obtained from a patient with chronic myelogenous leukemia (CML). We have characterized the GIG-1 gene and its protein product. Expression of GIG-1 mRNA was elevated by treatment with G-CSF in normal bone marrow mononuclear cells, as well as in some cases of blast cells obtained from patients with acute myelogenous leukemia (AML) and CML. Western blot analysis with anti-GIG-1 peptide antiserum showed the molecular mass of GIG-1 product was about 17 kDa. Immunostaining of the hematopoietic cells demonstrated that GIG-1 product was mainly localized to the cytoplasm of both myeloid and natural killer (NK) cells. These results suggested that GIG-1 protein is an integral component that is accumulated during the differentiation of myeloid cells toward the stage of mature neutrophils. Expression of GIG-1 gene in mature neutrophils was tightly regulated and reactivation of GIG-1 gene by G-CSF in mature neutrophils may represent a compensation process for the protein lost through the activation of these cells, thus implying an important role for this protein in host defense mechanisms.

IL-2/LAK therapy for refractory acute monoblastic leukemia relapsing after unrelated allogeneic bone marrow transplantation

Leukemia relapse is a major cause of treatment failure after allogeneic bone marrow transplantation. We administered recombinant interleukin-2 (rIL-2) to a patient who relapsed after unrelated allogeneic bone marrow transplantation (uBMT). While the number of peripheral blood monoblastic leukemia cells increased after administration of rIL-2, the patient achieved durable remission for 5 months after low-dose chemotherapy followed by adoptive transfer of engrafted graft-derived lymphokine-activated killer (LAK) cells. Following the disappearance of the blast cells, however, both cutaneous and liver GVHD were exacerbated. Administration of rIL-2 and adoptive transfer of graft-derived LAK cells are considered to be possible choices for the treatment of acute leukemia relapsing after uBMT when donor leukocyte transfusion is not available.

Vaccine effect of granulocyte-macrophage colony-stimulating factor or CD80 gene-transduced murine hematopoietic tumor cells and their cooperative enhancement of antitumor immunity

To develop immunogene therapy targeting minimal residual hematopoietic tumor cells in patients, we transduced murine GM-CSF or CD80 gene into murine WEHI 3B myelomonocytic leukemia and EL-4 thymic lymphoma cells using retroviral vectors and evaluated their effects on inducing antitumor responses in syngeneic host mice. Subcutaneously injected GM-CSF- and CD80 gene-transduced WEHI 3B (GMCSF/WEHI/3.2 or CD80/WEHI/1.8, respectively) cells lost their original tumorigenicity in immunocompetent syngeneic mice. Results from tumor inoculation experiments using athymic nude mice suggested that the rejection of GMCSF/WEHI/3.2 in immunocompetent mice depended fully on T cells and that of CD80/WEHI 1.8 depended partly on T cells and partly on NK cells. In both WEHI 3B and EL-4 models, irradiated GM-CSF gene-transduced cells provided strong immuno-protection against wild-type cells, but irradiated CD80 gene-transduced cells did not. A remarkably high cooperative effect was obtained when irradiated GMCSF/EL-4 and CD80/EL-4 were inoculated together. These results suggested that the tumor vaccine effect is efficiently enhanced by GM-CSF gene transduction and CD80 gene transduction induces some protective antitumor immunity in co-operation with GM-CSF gene transduction.

Relevance of periglomerular myofibroblasts in progression of human glomerulonephritis

To clarify the pathological and clinical significance of periglomerular alpha-smooth muscle actin (alpha-SMA)-positive cells, we examined 51 needle-biopsy specimens from patients with human glomerulonephritis. Immunoelectron microscopy confirmed these cells were myofibroblasts showing characteristic features with abundant alpha-SMA-positive thin myofilaments. Nonsclerotic glomeruli with periglomerular myofibroblasts were larger in the Bowman's capsular planar area than nonsclerotic glomeruli without periglomerular myofibroblasts (24.7 +/- 6.0 x 10(3) microm2 v 19.9 +/- 8.5 x 10(3) microm2; P < 0.01). We studied the correlation between the clinical prognosis and the extent of periglomerular myofibroblasts in 24 patients with IgA nephropathy. Patients were divided into two groups; those with plasma creatinine levels within normal range at biopsy and significantly elevated at follow-up were designated group 1 (poor prognosis), and patients with plasma creatinine levels within normal range at biopsy and not significantly elevated at follow-up were designated group 2 (fair prognosis). In the kidneys of group 1 patients, periglomerular alpha-SMA was expressed more intensively than it was in the kidneys of group 2 patients (alpha-SMA expression score, 1.0 +/- 0.48 v 0.52 +/- 0.54; P < 0.05). These findings indicate that periglomerular myofibroblasts appeared surrounding the nonsclerotic hypertrophic glomeruli, which may lead finally to glomerulosclerosis. This report suggests that interaction between the glomerular cells and the periglomerular myofibroblasts may have a role in the progression of glomerular diseases.

Thrombopoietin induces tyrosine phosphorylation of a common beta subunit of GM-CSF receptor and its association with Stat5 in TF-1/TPO cells

TF-1/TPO cells are derived from an erythroleukemia cell line, TF-1, and are absolutely dependent on either TPO or granulocyte-macrophage colony-stimulating factor (GM-CSF)/interleukin-3 (IL3) for their continuous growth and survival. To gain insight into the molecular basis of hemopoietic activities shared by TPO and GM-CSF/IL3 in TF-1/TPO cells, we studied the cross-talk between signal transduction pathways elicited by these cytokines. Stimulation of TF-1/TPO cells with TPO resulted in tyrosine phosphorylation of the TPO receptor (c-Mpl) as well as the common beta subunit (beta c) of GM-CSF/IL3 receptor complex. GM-CSF, however, induced tyrosine phosphorylation of beta c but not c-Mpl. TPO-induced tyrosine phosphorylation of beta c was time- and dose-dependent. We next examined whether or not TPO-induced tyrosine phosphorylation of beta c led to recruitment of SH2-containing molecules such as Stat5 and Shc. While GM-CSF caused association of Stat5 and Shc with beta c, TPO caused association of Stat5, but not Shc, with beta c, suggesting that TPO and GM-CSF may not induce phosphorylation of the same sets of tyrosine residues in beta c. These results suggest that activation of c-Mpl affects the signaling pathway of GM-CSF/IL3 but not vice versa.

Establishment of novel cell lines derived from two patients with chronic myelogenous leukemia in blast crisis; IMS-BC1 and IMS-BC2 which exhibit markedly different sensitivity to apoptosis

We established two novel cell lines, designated as IMS-BC1 and IMS-BC2, from two patients with chronic myelogenous leukemia in blast crisis. The two cell lines were positive for CD13 and CD33 and negative for CD34 and HLA-DR by surface marker analysis. IMS-BC1 had four Philadelphia (Ph1) chromosomes and a breakpoint within the 3'-portion of M-bcr, and IMS-BC2 had five Ph1 chromosomes and two breakpoints within the 3'- and 5'-portions of M-bcr. Both cell lines' growth activities were moderately suppressed by IFN-alpha. The proliferation of IMS-BC2 was inhibited by IFN-gamma and apoptosis was induced within 72 h, while IMS-BC1 was resistant to IFN-gamma. Fibronectin inhibited the proliferation of the two cell lines at higher than 10 micrograms/ml, but only IMS-BC2 showed apoptosis. Transforming growth factor-beta inhibited the proliferation of IMS-BC2 resulting in apoptosis, while it inhibited that of IMS-BC1 moderately but failed to induce apoptosis. All-trans retinoic acid (ATRA) inhibited the proliferation of IMS-BC2 at very low concentration (10(-17) mol/l) and induced apoptosis at doses higher than 10(-9) mol/l within 72 h without terminal differentiation, while IMS-BC1 was completely resistant to ATRA. The two cell lines showed different responses to growth inhibitory cytokines and factors. These cell lines should prove useful in the analysis of mechanisms of apoptosis induced by growth inhibitory cytokines and factors.