Role of endogenous adrenomedullin in the regulation of vascular tone and ischemic renal injury: studies on transgenic/knockout mice of adrenomedullin gene

Adrenomedullin (AM) is a potent depressor peptide whose vascular action is suggested to involve nitric oxide (NO) release. To explore the role of endogenous AM in vascular and renal function, we examined the effects of acetylcholine (ACh), AM, and AM receptor antagonists AM(22-52) and CGRP(8-37) on the renal perfusion pressure (RPP) of kidneys isolated from AM transgenic (TG)/heterozygote knockout (KO) mice and wild-type littermates (WT). Furthermore, we evaluated the renal function and histology 24 hours after bilateral renal artery clamp for 45 minutes in TG, KO, and WT mice. Baseline RPP was significantly lower in TG than in KO and WT mice (KO 93.4+/-4.6, WT 85.8+/-4.2, TG 72.4+/-2.4 mm Hg [mean+/-SE], P<0.01). ACh and AM caused a dose-related reduction in RPP, but the degree of vasodilatation was smaller in TG than that in KO and WT (%DeltaRPP 10(-7) mol/L ACh: KO -48.1+/-3.9%, WT -57.5+/-5.6%, TG -22.8+/-4.8%, P<0.01), whereas N(G)-nitro-L-arginine methyl ester (L-NAME) caused greater vasoconstriction in TG (%DeltaRPP 10(-4) mol/L: KO 33.1+/-3.3%, WT 55.5+/-7.2%, TG 152.6+/-21.2%, P<0.01). Both AM antagonists increased RPP in TG to a greater extent compared with KO and WT mice (%DeltaRPP 10(-6) mol/L CGRP(8-37): KO 12.8+/-2.6%, WT 19.4+/-3.6%, TG 41.8+/-8.7%, P<0.01). In mice with ischemic kidneys, serum levels of urea nitrogen and renal damage scores showed smaller values in TG and greater values in KO mice (urea nitrogen: KO 104+/-5>WT 98+/-15>TG 38+/-7 mg/dL, P<0.05 each). Renal NO synthase activity was also greater in TG mice. However, the differences in serum urea nitrogen and renal damage scores among the 3 groups of mice were not observed in mice pretreated with L-NAME. In conclusion, AM antagonists increased renal vascular tone in WT as well as in TG, suggesting that endogenous AM plays a role in the physiological regulation of the vascular tone. AM is likely to protect renal tissues from ischemia/reperfusion injury through its NO releasing activity.

Hematopoietic stem cells differentiate into vascular cells that participate in the pathogenesis of atherosclerosis

Excessive accumulation of smooth-muscle cells (SMCs) has a key role in the pathogenesis of vascular diseases. It has been assumed that SMCs derived from the outer medial layer migrate, proliferate and synthesize extracellular matrix components on the luminal side of the vessel. Although much effort has been devoted to targeting migration and proliferation of medial SMCs, there is no effective therapy that prevents occlusive vascular remodeling. We show here that in models of post-angioplasty restenosis, graft vasculopathy and hyperlipidemia-induced atherosclerosis, bone-marrow cells give rise to most of the SMCs that contribute to arterial remodeling. Notably, purified hematopoietic stem cells differentiate into SMCs in vitro and in vivo. Our findings indicate that somatic stem cells contribute to pathological remodeling of remote organs, and may provide the basis for the development of new therapeutic strategies for vascular diseases through targeting mobilization, homing, differentiation and proliferation of bone marrow-derived vascular progenitor cells.

Angiotensin II enhances glomerular expression of a nonmuscle myosin heavy chain, SMemb, with extracellular matrix accumulation

BACKGROUND/AIMS

We previously showed that the mesangial expression of nonmuscle-type myosin heavy chain, SMemb, was related to glomerular sclerosis. Although angiotensin II (AII) is known to promote the glomerular accumulation of extracellular matrix and sclerosis, the effect of AII on the mesangial expression of SMemb is unknown. Thus, we investigated the effect of AII on the mesangial expression of SMemb and synthesis of fibronectin.

METHODS

We continuously administered AII to Sprague-Dawley rats with subcutaneous osmotic minipumps for 14 days. Control animals received normal saline instead. The effects of oral administration of an AII type 1 (AT1) receptor antagonist, candesartan cilexetil, and a vasodilator, hydralazine, were also examined.

RESULTS

Semiquantitative immunohistochemical evaluation and Western blot analysis showed that AII significantly enhanced glomerular expression of SMemb (0.87 +/- 0.33 vs. 0.40 +/- 0.19 for immunohistochemical grading, p < 0.05; 2.55 +/- 0.88 vs. 1.16 +/- 0.75 for Western blot analysis, p < 0.05). Glomerular fibronectin was also increased in AII-administered rats (301.7 +/- 206.8 ng/5 microg protein vs. 95.8 +/- 81.3 ng/5 microg protein, p < 0.05). Candesartan cilexetil attenuated these effects. On the other hand, hydralazine did not change the glomerular expression of SMemb enhanced by AII administration.

CONCLUSION

All induced a phenotypic alteration in mesangial cells, enhanced the mesangial expression of SMemb and stimulated the fibronectin synthesis. These results suggest that the mesangial expression of SMemb is related to glomerular matrix accumulation and that AII mediates both mesangial processes via AT1 receptors.

Involvement of rat organic anion transporter 3 (rOAT3) in cephaloridine-induced nephrotoxicity: in comparison with rOAT1

This study was performed to elucidate the possible involvement of organic anion transporter 3 (OAT3) in cephaloridine (CER)-induced nephrotoxicity and compare the substrate specificity between rOAT3 and rat OAT1 (rOAT1) for various cephalosporin antibiotics, using proximal tubule cells stably expressing rOAT3 (S2 rOAT3) and rOAT1 (S2 rOAT1). S2 rOAT3 exhibited a CER uptake and a higher susceptibility to CER cytotoxicity than did mock, which was recovered by probenecid. Various cephalosporin antibiotics significantly inhibited both estrone sulfate uptake in S2 rOAT3 and para-aminohippuric acid uptake in S2 rOAT1. The Ki values of CER, cefoperazone, cephalothin and cefazolin for rOAT3- and rOAT1-mediated organic anion transport ranged from 0.048 to 1.14 mM and from 0.48 to 1.32 mM, respectively. These results suggest that rOAT3, at least in part, mediates CER uptake and CER-induced nephrotoxicity as rOAT1. There was some difference of affinity between rOAT3 and rOAT1 for cephalosporin antibiotics.

Distribution of stanniocalcin 1 in rat kidney and its regulation by vitamin D3

Stanniocalcin is a glycoprotein hormone first described in fish as a hypocalcemic factor, and recently its mammalian counterpart has been identified. Localization of stanniocalcin 1 and its regulation of expression were determined in control and 1alpha,25-dihydroxyvitamin D3-treated rats. Immunoreactivity for stanniocalcin 1 was detected in the loop of Henle, macula densa cells, distal convoluted tubule (DCT), and cortical collecting duct (CCD), and also faintly in the medullary collecting ducts. Pre-embedding electron-microscopic immunocytochemistry revealed stanniocalcin 1 in the apical membrane of cells of loop of Henle, DCT, and principal cells of CCD. The expression of stanniocalcin 1 was increased by elevated plasma calcium via 1alpha,25-dihydroxyvitamin D3 treatment. In conclusion, stanniocalcin 1 was expressed in the apical membrane of distal nephron segments and enhanced by vitamin D3.

Transient hematopoietic stem cell rescue using umbilical cord blood for a lethally irradiated nuclear accident victim

We performed stem cell rescue and allogeneic skin transplantation on a lethally neutron-irradiated nuclear accident victim. HLA-DRB1 mismatched unrelated umbilical cord blood cells (2.08 x 10(7)/kg recipient body weight) were transplanted to an 8-10 Gy equivalent neutron-irradiated patient because of a lack of a suitable bone marrow or peripheral blood donor. Pre-transplant conditioning consisted of anti-thymocyte gamma-globulin alone, and GVHD prophylaxis was a combination of cyclosporine (CYA) and methylprednisolone (mPSL). Granulocyte colony-stimulating factor (G-CSF), erythropoietin (EPO), and thrombopoietin (TPO) were concurrently administered after transplantation. The absolute neutrophil count reached 0.5 x 10(9)/l on day 15, the reticulocyte count rose above 1% on day 23, and the platelet count was over 50 x 10(9)/l on day 27, respectively. Cytogenetic studies of blood and marrow showed donor/recipient mixed chimerism. Rapid autologous hematopoietic recovery was recognized after withdrawal of CYA and mPSL. Repeated pathological examinations of the skin revealed no evidence of acute GVHD. Eighty-two days after the irradiation, skin transplantation was performed to treat radiation burns. Almost 90% of the transplanted skin engrafted. Immunological examination after autologous hematopoietic recovery revealed an almost normal T cell count. However, immune functions were severely impaired. The patient died from infectious complication 210 days after the accident.

Oxidative stress and nitric oxide synthase in rat diabetic nephropathy: effects of ACEI and ARB

BACKGROUND

Angiotensin II (Ang II) can up-regulate nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase, whose product superoxide anion (O2-) can interact with nitric oxide (NO) to form peroxynitrite (ONOO-). We tested the hypothesis that Ang II subtype 1 (AT1) receptor activation enhances oxidative stress and nitrotyrosine deposition in the kidneys of rats with diabetes mellitus (DM).

METHODS

After two weeks of streptozotocin-induced DM, rats received either no treatment, an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin receptor blocker (ARB) for two weeks. At four weeks, renal expression of the p47phox component of NAD(P)H oxidase, endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS), and nitrotyrosine were evaluated by Western blot and immunohistochemistry and related to plasma lipid peroxidation products (LPO), hydrogen peroxide production in the kidney and 24-hour protein excretion.

RESULTS

Immunoreactive expression of p47phox and eNOS were increased in DM with an increase in plasma LPO, renal hydrogen peroxide production and nitrotyrosine deposition. Expression of nNOS was unaltered. Treatment with either ACEI or ARB prevented all these findings and also prevented significant microalbuminuria. The treatments did not affect the elevated blood sugar, nor did DM or its treatment affect the blood pressure or the creatinine clearance.

CONCLUSION

Early proteinuric diabetic nephropathy increases renal expression of the p47phox component of NAD(P)H oxidase and eNOS with increased indices of systemic and renal oxidative/nitrosative stress. An ACEI or an ARB prevents these changes and prevents the development of proteinuria, independent of blood pressure or blood sugar. This finding indicates a pathogenic role for AT1 receptors in the development of oxidative damage in the kidneys during early DM.

[Interferon-alpha therapy]

Interferon-alpha (IFN alpha) with or without Ara-C is a choice of therapy for patients with CML who cannot receive allogeneic stem cell transplantation and gives those better prognosis than a conventional chemotherapy, although it has a variety of adverse effects. Especially, in a certain population(about 20%) of CML patients, IFN alpha can induce complete cytogenetic response in spite of persistant minimal residual disease. The basis of IFN alpha activity against CML is still unknown, but the contribution of immune-mediated mechanism is expected.

Tissue-specific induction of E-selectin in glomeruli is augmented following diabetes mellitus

We recently demonstrated that induction of adhesion molecules is tissue, cell type, and blood vessel size specific. We examined here whether the glomeruli, a peculiar vascular system, express adhesion molecules in a specific manner in the murine kidney. In addition, since serum levels of soluble adhesion molecules have been reported to be elevated in diabetic patients, we examined the influence of diabetes mellitus on the induction of adhesion molecules in the kidney. Analysis of E-selectin mRNA expression by in situ hybridization indicated that it was selectively induced in glomeruli by intravenous administration of interleukin-1beta, while ICAM-1 mRNA expression was seen diffusely in endothelium lining the small arteries and capillaries or in glomeruli, and VCAM-1 mRNA expression was most prominent in endothelial cells of larger blood vessels. Induction of E-selectin mRNA expression in glomeruli by proinflammatory stimuli was augmented in streptozotocin-induced diabetic mice as compared with control mice, while ICAM-1 or VCAM-1 mRNA induction was only slightly influenced. Furthermore, immunohistochemical analysis showed that selective expression of E-selectin in glomeruli was augmented predominantly in epithelial cells, depending on the duration of diabetes mellitus, in KK-Ay mice. These findings suggest that glomerulus-specific expression of E-selectin is related to the development of diabetic nephropathy.

Characterization of ochratoxin A transport by human organic anion transporters

The purpose of this study was to investigate the characteristics of ochratoxin A (OTA) transport by multispecific human organic anion transporters (hOAT1 and hOAT3, respectively) using the second segment of proximal tubule (S2) cells from mice stably expressing hOAT1 and hOAT3 (S2 hOAT1 and S2 hOAT3). S2 hOAT1 and S2 hOAT3 exhibited a time- and dose-dependent, and a saturable increase in uptake of [3H]-OTA, with apparent Km values of 0.42 microM (hOAT1) and 0.75 microM (hOAT3). These OTA uptakes were inhibited by several substrates for the OATs. Para-aminohippuric acid (PAH), probenecid, piroxicam, octanoate and citrinin inhibited [3H]-OTA uptake by hOAT1 and hOAT3 in a competitive manner (Ki = 4.29-3080 microM), with the following order of potency: probenecid > octanoate > PAH > piroxicam > citrinin for hOAT1; probenecid > piroxicam > octanoate> citrinin > PAH for hOAT3. These results indicate that hOAT1, as well as hOAT3, mediates a high-affinity transport of OTA on the basolateral side of the proximal tubule, but hOAT1- and hOAT3-mediated OTA transport are differently influenced by the substrates for the OATs. These pharmacological characteristics of hOAT1 and hOAT3 may be significantly related with the events in the development of OTA-induced nephrotoxicity in the human kidney.

Reduced albumin reabsorption in the proximal tubule of early-stage diabetic rats

The aim of this study is to investigate the role of the proximal tubule in microalbuminuria in the early stage of diabetic nephropathy. Diabetes was induced in male Sprague-Dawley rats by an injection of streptozotocin (50 mg/kg, i.v.). After 2 weeks, albumin delivery in the proximal tubule was measured using micropuncture and the endocytosis process of FITC-labeled albumin was evaluated with immunoelectron microscopy. Albumin was significantly reabsorbed in the proximal convoluted tubule (PCT) of controls (0.39+/-0.05 ng/min at early PCT to 0.17+/-0.08 at late PCT, P<0.05), whereas albumin reabsorption was inhibited in diabetic rats (0.27+/-0.05 to 0.21+/-0.08). Immunogold study revealed that FITC-albumin was significantly less reabsorbed in endosomes and lysosomes of S1 segments in diabetic rats than in controls (endosome: 1.20+/-0.10 vs 2.16+/-0.15 microm-1, P<0.0001; lysosome: 0.26+/-0.03 vs 0.83+/-0.07, P<0.0001). The expression of megalin, an endocytosis receptor, was decreased at the apical membrane of PCT in diabetic rats. The lipid peroxidation production in the proximal tubule was significantly increased in diabetic rats. In conclusion, albuminuria in early-stage diabetic rats can be partly explained by a decreased albumin endocytosis with reduced megalin expression and with increased lipid peroxidation in the proximal tubule.

Unrelated cord blood transplantation for adult patients with myelodysplastic syndrome-related secondary acute myeloid leukaemia

Seven adult patients with myelodysplastic syndrome (MDS)-related secondary acute myeloid leukaemia (AML) were treated with total body irradiation (TBI), cytosine arabinoside (Ara-C) and cyclophosphamide (CY), followed by unrelated human leucocyte antigen (HLA)-mismatched cord blood transplantation (CBT). Granulocyte colony-stimulating factor (G-CSF) was infused continuously from 12 h before until the end of Ara-C therapy to enhance the antileukaemia effect of Ara-C. Five patients are alive and free of disease at 7-31 months after transplantation. These preliminary results suggest that adult MDS-related secondary AML patients without suitable related or unrelated bone marrow donors should be considered as candidates for CBT.

Severe autoimmune thrombocytopenia after allogeneic bone marrow transplantation for aplastic anemia

Autoimmune thrombocytopenia (AITP) after bone marrow transplantation (BMT) was suggested to occur by immune dysregulation mainly in association with graft-versus-host disease (GVHD). Here we present a patient who developed severe AITP after BMT. A 40-year-old woman with severe aplastic anemia received a BMT from a partially HLA-matched brother. Despite myeloid and erythroid engraftments, platelet recovery was delayed. All bone marrow cells were 46,XY and were derived from the donor. Grade I acute GVHD involving skin developed from day 34 posttransplantation, but promptly responded to prednisolone in addition to a prophylactic dose of tacrolimus. With the tapering of prednisolone, thrombocytopenia progressed without substantial changes in the white blood cell count, hemoglobin concentration, or reticulocyte count. On day 188, the patient developed chronic GVHD involving skin and liver, which promptly responded to the readministration of prednisolone and increased tacrolimus. However, the patient's platelet count decreased to 9 x 10(9) cells/L on day 222. The platelet-associated immunoglobulin G (PAIgG) values were elevated. Bone marrow examination showed hypercellularity with plentiful megakaryocytes. The number of colony-forming units-megakaryocyte was within the normal range. The elevated PAIgG values and a correlation between thrombocytopenia and the intensity of the immunosuppressive agents strongly suggested a causative role of the autoimmune mechanisms for thrombocytopenia in this patient.

Haematopoietic progenitor cells from the common marmoset as targets of gene transduction by retroviral and adenoviral vectors

To establish a new non-human primate model for human cytokine and gene therapy, we characterized lymphocytes and haematopoietic progenitor cells of the small New World monkey, the common marmoset. We first assessed the reactions of marmoset bone marrow (BM) and peripheral blood (PB) cells to mouse anti-human monoclonal antibodies (mAbs) for the purpose of isolating marmoset lymphocytes and haematopoietic progenitor cells. Both cell fractions stained with CD4 and CD8 mAbs were identified as lymphocytes by cell proliferation assay and morphological examination. Myeloid-specific mAbs such as CD14 and CD33 did not react with marmoset BM and PB cells. No available CD34 and c-kit mAbs could be used to purify the marmoset haematopoietic progenitor cells. Furthermore, we studied the in vitro transduction of the bacterial beta-galactosidase (LacZ) gene into CFU-GM derived from marmoset BM using retroviral and adenoviral vectors. The transduction efficiency was increased by using a mixed culture system consisting of marmoset BM stromal cells and retroviral producer cells. It was also possible to transduce LacZ gene into marmoset haematopoietic progenitor cells with adenoviral vectors as well as retroviral vectors. The percentage of adenovirally transduced LacZ-positive clusters was 15% at day 4 (multiplicity of infection=200), but only 1-2% at day 14. The differential use of viral vector systems is to be recommended in targeting different diseases. Our results suggested that marmoset BM progenitor cells were available to examine the transduction efficiency of various viral vectors in vitro.

Tubulointerstitial nephritis associated with acute intermittent porphyria

Progressive renal impairment associated with acute intermittent porphyria is not well recognized and the mechanism of renal damage remains unclear. We report a case of a 51-year-old female with acute intermittent porphyria and long-term follow-up who developed proteinuria and renal insufficiency. Her biopsy showed marked tubulointerstitial damage with mitochondrial abnormalities. Urinary excretion of lipid peroxidation was increased compared to healthy controls. The porphyrin precursors may increase lipid peroxidation products and damage mitochondria leading to tubulointerstitial nephritis.

Renal expression of constitutive NOS and DDAH: separate effects of salt intake and angiotensin

BACKGROUND

Nitric oxide (NO) is generated from NO synthase (NOS) isoforms. These enzymes can be inhibited by asymmetric dimethylarginine, which is inactivated by N(G)-N(G)-dimethylarginine dimethylaminohydrolase (DDAH). The neuroneal (nNOS) type I and endothelial (eNOS) type III constitutive NOS isoforms are expressed predominantly in the macula densa and microvascular endothelium of the renal cortex, respectively. DDAH is expressed at sites of NOS expression. Since NO may coordinate the renal responses to angiotensin II (Ang II) and changes in salt intake, we tested the hypothesis that salt intake regulates the expression of nNOS, eNOS and DDAH by Ang II acting on type 1 (AT(1)) receptors.

METHODS

Groups (N = 6) of rats were adapted to low-salt (LS) or high-salt (HS) intakes for 10 days. Other groups of LS and HS rats received the AT(1) receptor antagonist losartan for six days (to test the effects of salt independent of AT(1) receptors). A further group of HS rats received an infusion of Ang II for six days (to test the effect of Ang II independent of salt intake).

RESULTS

Compared with HS rats, there was a significant (P < 0.05) increase in LS rats of nNOS protein in kidney and immunohistochemical expression in the macula densa, and of eNOS protein expression and immunohistochemical expression in the microvascular endothelium, and of DDAH protein expression. Losartan prevented these effects of salt on the expression of eNOS or DDAH, both of which were also increased by Ang II infusions in HS rats. In contrast, losartan did not prevent the effects of salt on nNOS expression, which was unresponsive to Ang II infusion. The generation of NO(2)(-) released by slices of renal cortex, in the presence of saturating concentrations of L-arginine, was increased by LS, compared to HS, independent of losartan and by Ang II during HS.

CONCLUSION

The expressions of eNOS in cortical microvascular endothelium and DDAH in kidney are enhanced by Ang II acting on AT(1) receptors. The expression of nNOS in the macula densa is enhanced by salt restriction independent of Ang II or AT(1) receptors.

Localization of inward rectifier potassium channel Kir7.1 in the basolateral membrane of distal nephron and collecting duct

Inward rectifier potassium channels (Kir) play an important role in the K(+) secretion from the kidney. Recently, a new subfamily of Kir, Kir7.1, has been cloned and shown to be present in the kidney as well as in the brain, choroid plexus, thyroid, and intestine. Its cellular and subcellular localization was examined along the renal tubule. Western blot from the kidney cortex showed a single band for Kir7.1 at 52 kD, which was also observed in microdissected segments from the thick ascending limb of Henle, distal convoluted tubule (DCT), connecting tubule, and cortical and medullary collecting ducts. Kir7.1 immunoreactivity was detected predominantly in the DCT, connecting tubule, and cortical collecting duct, with lesser expression in the thick ascending limb of Henle and in the medullary collecting duct. Kir7.1 was detected by electron microscopic immunocytochemistry on the basolateral membrane of the DCT and the principal cells of cortical collecting duct, but neither type A nor type B intercalated cells were stained. The message levels and immunoreactivity were decreased under low-K diet and reversed by low-K diet supplemented with 4% KCl. By the double-labeling immunogold method, both Kir7.1 and Na(+), K(+)-ATPase were independently located on the basolateral membrane. In conclusion, the novel Kir7.1 potassium channel is located predominantly in the basolateral membrane of the distal nephron and collecting duct where it could function together with Na(+), K(+)-ATPase and contribute to cell ion homeostasis and tubular K(+) secretion.

Mesangial expression of a nonmuscle myosin heavy chain, SMemb, is associated with glomerular sclerosis and renal prognosis in IgA nephropathy

To characterize the phenotypic alteration in mesangial cells in human glomerulonephritis, we investigated the expression of nonmuscle-type myosin heavy chain, SMemb, and alpha-smooth muscle actin (alpha-SM actin) in IgA nephropathy. The expression of SMemb and alpha-SM actin was examined by immunohistochemistry in biopsy specimens from 45 patients with IgA nephropathy. We examined a total of 489 glomeruli representing all patients enrolled, and found that mesangial expression of SMemb and alpha-SM actin was associated with mesangial proliferation. Only mesangial expression of SMemb showed a significant relationship with mesangial matrix accumulation. Semiquantitative evaluation using composite expression scores showed that the expression of SMemb was elevated in the patients with poor renal prognosis. The expression of alpha-SM actin showed no significant relationship with renal prognosis. These results suggest that mesangial expression of SMemb is an important factor in the progression of IgA nephropathy, and that SMemb and alpha-SM actin are associated with the activation of mesangial cells by different mechanisms.

Progress reports on immune gene therapy for stage IV renal cell cancer using lethally irradiated granulocyte-macrophage colony-stimulating factor-transduced autologous renal cancer cells

There is no effective treatment for patients with stage IV renal cell cancer (RCC), although the introduction of new therapy is imminent. Cancer gene therapy is currently considered to be one of the most promising therapeutic modalities in the field of cancer treatment. Based on the results of animal studies, vaccination using autologous granulocyte-macrophage colony-stimulating factor-transduced renal cancer cells appears promising. Before initiating a clinical study using an ex vivo gene-transduced autologous cell vaccine-based immunogene therapy for RCC in Japan, in 1992 we initially planned a Japanese version of a clinical protocol in collaboration with a US group. In 1993, the original protocol was refined. We performed five preclinical qualification studies using RCC nephrectomy specimens from patients in 1997, and the results showed that preparation of RCC cells for autologous vaccines at the Clinical Cell Technology Facility, Research Hospital of the Institute of Medical Science, University of Tokyo, was feasible. Subsequently in August 1998, the Ministry of Health and Welfare and the Ministry of Education, Science, Culture, and Sport approved our clinical protocol. We have recruited two patients with stage IV RCC to our study so far. Here we report the background to the initiation of cancer gene therapy in Japan.

MHC (major histocompatibility complex)-DRB genes and polymorphisms in common marmoset

A New World monkey, the common marmoset (Callithrix jacchus), will be used as a preclinical animal model to study the feasibility of cell and gene therapy targeting immunological and hematological disorders. For elucidating the immunogenetic background of common marmoset to further studies, in the present study, polymorphisms of MHC-DRB genes in this species were examined. Twenty-one Caja-DRB exon 2 alleles, including seven new ones, were detected by means of subcloning and the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) methods followed by nucleotide sequencing. Based on the alignment of these allele sequences, we designed two pairs of specific primers and established a PCR-SSCP method for DNA-based histocompatibility typing of the common marmoset. According to the family segregation data and phylogenetic analyses, we presumed that Caja-DRB alleles could be classified into five different loci. Southern blotting analysis also supported the existence of multiple DRB loci. The patterns of nucleotide substitutions suggests that positive selection operates in the antigen-recognition sites of Caja-DRB genes.

Hyperfunction of neutrophils in a patient with BCR/ABL negative chronic myeloid leukemia: a case report with in vitro studies

BACKGROUND

Among patients diagnosed with chronic myeloid leukemia (CML), a small percentage lack a BCR/ABL fusion gene, a landmark of CML. Their clinical features are distinct from patients with BCR/ABL positive CML, although to the authors' knowledge the pathogenesis to date has been unknown.

METHODS

A 50-year-old female patient with BCR/ABL negative CML and multiple complications of Graves disease, Sweet syndrome, and a fatal pulmonary alveolar proteinosis (PAP) is described in the current study. To show a clonal origin of her myeloid cells, hypoxanthine phosphoribosyltransferase (HPRT) assay was applied. Because the patient developed a progressive and fatal neutrophilia, a screening of cell functions in neutrophilic lineage, including in vitro colony assay of her bone marrow cells and production of superoxide and interleukin-8 (IL-8) by blood neutrophils was performed.

RESULTS

Southern blot analysis based on the polymorphism of the HPRT gene was compatible with monoclonality of her neutrophils. The patient had an increased amount of bone marrow granulocyte-macrophage progenitor cells, which formed colonies in response to a very low dose (0.1 ng/mL) of granulocyte-colony stimulating factor. In vitro production of superoxide and IL-8, which is an inducer of positive chemotaxis of neutrophils, by her peripheral neutrophils was markedly augmented. Her bronchoalveolar lavage fluid also contained a significant amount of IL-8 as well as an unusual infiltration of neutrophils.

CONCLUSIONS

In the patient in the current study, hyperfunction of the neutrophils might have contributed to the onset of PAP as well as Sweet syndrome and to the pathogenesis of BCR/ABL negative CML.

Refractory facial cellulitis following cosmetic rhinoplasty after cord-blood stem cell transplantation

We report a case of a 38-year-old female patient who developed facial cellulitis after cord-blood stem cell transplantation (CBT). The cellulitis was refractory to treatment with antibiotics and antifungal agents. Because facial cellulitis is rare after transplantation, its mechanism could not be determined exactly. On day 40 after CBT, a nurse with expertise in cosmetic surgery attended our rounds and correctly assumed that the patient had received cosmetic rhinoplasty. Although conventional x-rays of the head were normal, a computed tomographic (CT) scan of the brain disclosed the presence of a foreign body over the nasal dorsum. As a result, the patient's symptoms were diagnosed as facial cellulitis associated with foreign material that had been implanted at the time of cosmetic surgery. At a pretransplantation interview, the patient did not mention her history of rhinoplasty. Even after she was shown the head CT scans that revealed the presence of nasal implants, she denied that she had received rhinoplasty before CBT. Unless we realize that patients may have received cosmetic surgery before transplantation, it is difficult to make a diagnosis of infection associated with foreign implants. To our knowledge this is the first report after transplantation of infection associated with cosmetic surgery. Such infections should be included on the list of complications after bone marrow transplantation.

TCR-Vbeta repertoire analysis with RT-PCR was useful for the early detection of pulmonary relapsed T-cell lymphoma after autologous peripheral blood stem cell transplantation

Pulmonary recurrence of malignant lymphoma is a rare event after stem cell transplantation. We report here a 45-year-old male who was successfully diagnosed with relapsed pulmonary T-cell lymphoma using an RT-PCR method. Clonal expansion of T cells expressing identical TCR V-D-J junction size (Vbeta5-Jbeta1.5) was demonstrated in lymphocyte groups obtained from both bronchoalveolar lavage fluid at relapse, and paraffin embedded lymph node samples resected when he was first diagnosed with angioimmunoblastic T-cell lymphoma. This method provided evidence to diagnose relapsed pulmonary angioimmunoblastic T-cell lymphoma in its early phase.

Roles of NO and oxygen radicals in tubuloglomerular feedback in SHR

The spontaneously hypertensive rat (SHR) has enhanced tubuloglomerular feedback (TGF) responses and diminished buffering by juxtaglomerular apparatus (JGA)-derived nitric oxide (NO) despite enhanced expression of NO synthase (NOS) isoforms in the JGA. We tested the hypothesis that the enhanced TGF response is due to inactivation of NO by oxygen radicals (O(-)(2)). SHR had significantly (P<0.05) greater expression of the peroxynitrate reaction product, nitrotyrosine, in renal cortex. A membrane-permeant, metal-independent superoxide dismutase mimetic, tempol, was used to test the functional role of O(-)(2). Maximum TGF responses, assessed from changes in proximal stop-flow pressure (P(SF)) during orthograde loop of Henle (LH) perfusion of artificial tubular fluid (ATF), were enhanced in SHR [Wistar-Kyoto rat (WKY) 8.8+/-0.4 (n = 30 nephrons) vs. SHR 10.8+/-0.4 mm Hg (n = 39 nephrons), P<0.001]. TGF responses of SHR were unresponsive to microperfusion of 7-nitroindazole (7-NI, 10(-4) M), which is an inhibitor of neuronal NOS (nNOS) [WKY 8.3+/-0.3 to 10.8+/-0.4 (n = 8, P<0.001) vs. SHR 10.0+/-0.7 to 10.5+/-0.8 mm Hg (n = 8; not significant)]. Microperfusion of tempol (10(-4) M) into the efferent arteriole (EA) supplying the peritubular capillaries (PTC) blunted TGF. The response to tempol was significantly (P< 0.05) greater in SHR [DeltaTGF in WKY 19+/-6% (n = 10) vs. SHR 32+/-3% (n = 10)]. Microperfusion of the NO donor compound S-nitroso-N-acetyl-penicillamine (SNAP, 10(-7)-10(-4) M) via the LH blunted TGF, but the sensitivity of the response was impaired significantly (P<0.05) in SHR nephrons. PTC perfusion of tempol (10(-4) M) normalized the response to loop perfusion of both SNAP and 7-NI in SHR nephron to levels in WKY (during tempol, DeltaP(SF) with 7-NI in WKY 8.9+/-0.6 to 11.4+/-0.8; n = 12 vs. SHR 9.5+/-0.5 to 12.5+/-0.4 mm Hg; n = 16). In conclusion, TGF responses are enhanced in SHR, in part due to a diminished role for NO from nNOS in blunting TGF due to enhanced O(-)(2) formation. O(-)(2) in the JGA enhances TGF responses by inactivation of locally generated NO.

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.