A rat model for retinitis pigmentosa with rapid retinal degeneration enables drug evaluation in vivo

Background

Although retinitis pigmentosa (RP) is most frequently studied in mouse models, rats, rabbits, and pigs are also used as animal models of RP. However, no studies have reported postnatal photoreceptor cell loss before complete development in these models. Here, we generated a transgenic rat strain, named the P347L rat, in which proline at position 347 in the rhodopsin protein was replaced with leucine.

Results

A pathological analysis of photoreceptor cells in the P347L rat model was performed, and drugs with potential use as therapeutic agents against RP were investigated. The data clearly showed rapid degeneration and elimination of the outer nuclear layer even before the photoreceptor cells were fully established in P347L rats. To test the usefulness of the P347L rat in the search for new therapeutic agents against RP, the effects of rapamycin on RP were investigated in this rat strain. The findings suggest that rapamycin promotes autophagy and autophagosomal uptake of the rhodopsin that has accumulated abnormally in the cytoplasm, thereby alleviating stress and delaying photoreceptor cell death.

Conclusions

In this RP model, the time to onset of retinal degeneration was less than that of previously reported RP models with other rhodopsin mutations, enabling quicker in vivo evaluation of drug efficacy. Administration of rapamycin delayed the photoreceptor cell degeneration by approximately 1 day.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12575-021-00150-y.

Selective overexpression of cytoglobin in stellate cells attenuates thioacetamide-induced liver fibrosis in mice

Cytoglobin (CYGB), discovered in hepatic stellate cells (HSCs), is known to possess a radical scavenger function, but its pathophysiological roles remain unclear. Here, for the first time, we generated a new transgenic (TG) mouse line in which both Cygb and mCherry reporter gene expression were under the control of the native Cygb gene promoter. We demonstrated that the expression of Cygb-mCherry was related to endogenous Cygb in adult tissues by tracing mCherry fluorescence together with DNA, mRNA, and protein analyses. Administration of a single dose (50 mg/kg) of thioacetamide (TAA) in Cygb-TG mice resulted in lower levels of alanine transaminase and oxidative stress than those in WT mice. After 10 weeks of TAA administration, Cygb-TG livers exhibited reduced neutrophil accumulation, cytokine expression and fibrosis but high levels of quiescent HSCs. Primary HSCs isolated from Cygb-TG mice (HSCCygb-TG) exhibited significantly decreased mRNA levels of α-smooth muscle actin (αSMA), collagen 1α1, and transforming growth factor β-3 after 4 days in culture relative to WT cells. HSCsCygb-TG were resistant to H2O2-induced αSMA expression. Thus, cell-specific overexpression of Cygb attenuates HSC activation and protects mice against TAA-induced liver fibrosis presumably by maintaining HSC quiescence. Cygb is a potential new target for antifibrotic approaches.

Anti-drug Antibodies Against a Novel Humanized Anti-CD20 Antibody Impair Its Therapeutic Effect on Primary Biliary Cholangitis in Human CD20- and FcγR-Expressing Mice

There is considerable interest in expanding B cell-targeted therapies in human autoimmune diseases. However, clinical trials in human primary biliary cholangitis (PBC) using a chimeric antibody against human CD20 (hCD20) have showed limited efficacy. Two potential explanations for these disappointing results are the appearance of anti-drug antibodies (ADAs) and the high frequency of patients with moderate PBC or patients who had failed ursodeoxycholic acid treatment. Here, we studied a novel humanized IgG1 antibody against hCD20 and explored its efficacy in early stage PBC using a well-defined murine model. We developed a unique murine model consisting of dnTGF-βRII mice expressing hCD20 and human Fcγ receptors (hFcγRs). Beginning at 4–6 weeks of age, equivalent to stage I/II human PBC, female mice were given weekly injections of an anti-hCD20 antibody (TKM-011) or vehicle control, and monitored for liver histology as well as a broad panel of immunological readouts. After 16 weeks' treatment, we observed a significant reduction in portal inflammation, a decrease in liver-infiltrating mononuclear cells as well as a reduction in liver CD8⁺ T cells. Importantly, direct correlations between numbers of liver non-B cells and B cells (r = 0.7426, p = 0.0006) and between numbers of liver memory CD8⁺ T cells and B cells (r = 0.6423, p = 0.0054) were apparent. Accompanying these changes was a dramatic reduction in anti-mitochondrial antibodies (AMAs), interleukin (IL)-12p40 and IL-5, and elevated levels of the anti-inflammatory chemokine CXCL1/KC. In mice that developed ADAs, clinical improvements were less pronounced. Sustained treatment with B cell-targeted therapies may broadly inhibit effector pathways in PBC, but may need to be administered early in the natural history of PBC.

Generation of Novel Chimeric Mice with Humanized Livers by Using Hemizygous cDNA-uPA/SCID Mice

We have used homozygous albumin enhancer/promoter-driven urokinase-type plasminogen activator/severe combined immunodeficient (uPA/SCID) mice as hosts for chimeric mice with humanized livers. However, uPA/SCID mice show four disadvantages: the human hepatocytes (h-heps) replacement index in mouse liver is decreased due to deletion of uPA transgene by homologous recombination, kidney disorders are likely to develop, body size is small, and hemizygotes cannot be used as hosts as more frequent homologous recombination than homozygotes. To solve these disadvantages, we have established a novel host strain that has a transgene containing albumin promoter/enhancer and urokinase-type plasminogen activator cDNA and has a SCID background (cDNA-uPA/SCID). We applied the embryonic stem cell technique to simultaneously generate a number of transgenic lines, and found the line with the most appropriate levels of uPA expression—not detrimental but with a sufficiently damaged liver. We transplanted h-heps into homozygous and hemizygous cDNA-uPA/SCID mice via the spleen, and monitored their human albumin (h-alb) levels and body weight. Blood h-alb levels and body weight gradually increased in the hemizygous cDNA-uPA/SCID mice and were maintained until they were approximately 30 weeks old. By contrast, blood h-alb levels and body weight in uPA/SCID chimeric mice decreased from 16 weeks of age onwards. A similar decrease in body weight was observed in the homozygous cDNA-uPA/SCID genotype, but h-alb levels were maintained until they were approximately 30 weeks old. Microarray analyses revealed identical h-heps gene expression profiles in homozygous and hemizygous cDNA-uPA/SCID mice were identical to that observed in the uPA/SCID mice. Furthermore, like uPA/SCID chimeric mice, homozygous and hemizygous cDNA-uPA/SCID chimeric mice were successfully infected with hepatitis B virus and C virus. These results indicate that hemizygous cDNA-uPA/SCID mice may be novel and useful hosts for producing chimeric mice for use in future long-term studies, including hepatitis virus infection analysis or drug toxicity studies.

Activating transcription factor 6α is required for the vasopressin neuron system to maintain water balance under dehydration in male mice

Activating transcription factor 6α (ATF6α) is a sensor of endoplasmic reticulum (ER) stress and increases the expression of ER chaperones and molecules related to the ER-associated degradation of unfolded/misfolded proteins. In this study, we used ATF6α knockout (ATF6α(-/-)) mice to clarify the role of ATF6α in the arginine vasopressin (AVP) neuron system. Although urine volumes were not different between ATF6α(-/-) and wild-type (ATF6α(+/+)) mice with access to water ad libitum, they were increased in ATF6α(-/-) mice compared with those in ATF6α(+/+) mice under intermittent water deprivation (WD) and accompanied by less urine AVP in ATF6α(-/-) mice. The mRNA expression of immunoglobulin heavy chain binding protein, an ER chaperone, was significantly increased in the supraoptic nucleus in ATF6α(+/+) but not ATF6α(-/-) mice after WD. Electron microscopic analyses demonstrated that the ER lumen of AVP neurons was more dilated in ATF6α(-/-) mice than in ATF6α(+/+) mice after WD. ATF6α(-/-) mice that were mated with mice possessing a mutation causing familial neurohypophysial diabetes insipidus (FNDI), which is characterized by progressive polyuria and AVP neuronal loss due to the accumulation of mutant AVP precursor in the ER, manifested increased urine volume under intermittent WD. The aggregate formation in the ER of AVP neurons was further impaired in FNDI/ATF6α(-/-) mice compared with that in FNDI mice, and AVP neuronal loss was accelerated in FNDI/ATF6α(-/-) mice under WD. These data suggest that ATF6α is required for the AVP neuron system to maintain water balance under dehydration.

Spatial and temporal expression of RA70/Scap2 in the developing neural tube

Src kinase-associated phosphoprotein 2 (Ra70/scap2), which was originally isolated as a retinoic acid (RA)-induced gene, associates with molecules that modulate integrin-survival signals. Although RA is essential for vertebrate organogenesis in the posterior region, little is known about the biological role of RA70/Scap2 during development. In the present study, we demonstrate that Ra70/scap2 mRNA is temporally expressed during the RA-induced neuronal differentiation of P19 embryonic carcinoma cells. Homozygous knockout mice in which the Ra70/scap2 gene was replaced with LacZ exhibited embryonic lethality, while heterozygous mice displayed preferential expression of LacZ in posterior neural tissues, including the neural tube and hindbrain during development (E7.5-11.5), but not the forebrain. Ra70/scap2 was expressed in the ependymal layer and ventricular zone in the neural tube, where neuroepithelial cells and neuroblasts with proliferation capacity are localized, respectively. Thus, RA70/Scap2 may be necessary for RA-induced neuronal differentiation from the posterior neuroectoderm.

326 GENERATION OF A DOUBLE-TRANSGENIC PIG WITH PANCREAS-SPECIFIC GREEN AND LIVER-SPECIFIC RED FLUORESCENCE

Transgenic (Tg) pigs with organ/tissue-specific fluorescence expression provide invaluable research tools for many types of studies, such as organogenesis analysis, in vitro tissue generation from pluripotent cells, and progenitor/stem cell transplantation therapy. We aimed to develop a Tg pig characterised by pancreas- and liver-specific fluorescence expression. A 8.4 kb transgene construct expressing Venus (green fluorescence) under the control of the mouse Pdx1 (pancreatic duodenal homeobox-1) promoter and a BAC-derived construct (170 kb) consisting of the whole-length porcine albumin (Alb) promoter and humanized Kusabira-Orange (huKO, red fluorescence) was introduced into porcine in vitro-matured oocytes using the intracytoplasmic sperm injection (ICSI)-mediated gene transfer method. Injected embryos were transferred to the oviducts of oestrus-synchronized recipients after culture for 1 to 3 days. The transfer of 370 Pdx1-Venus embryos into 4 recipients produce 22 (5.9%) fetuses/piglets, and 9 (40.9%) Tg pigs exhibited pancreas-specific Venus expression. Two (1 male and 1 female) founder Pdx1-Venus-Tg pigs were mated with wild-type (WT) pigs and produced 32 offspring in 3 litters, of which 16 (50.0%) were transgenic. Pancreas-specific Venus expression was inherited in these Tg offspring. The transfer of 523 Alb-huKO embryos into 4 recipients resulted in 19 (3.6%) piglets including a Tg female, which showed liver-specific huKO fluorescent expression. Expression of huKO was detected by RT-PCR exclusively in liver, but not in 7 other organs/tissues examined, including heart, lung, stomach, small intestine, spleen, kidney and skin. This founder Tg female produced a total of 12 non-Tg and 5 Tg offspring (in 2 litters) after mating with a WT boar. Liver-specific huKO expression was inherited in these Tg offspring. Furthermore, the mating of a female Pdx1-Venus pig with an Alb-huKO boar yielded 7 non-Tg and 10 Tg pigs. Four of these Tg pigs carrying both of the transgenes exhibited both pancreas-specific Venus and liver-specific huKO expression in single individuals. Double-Tg pigs with pancreas-specific green fluorescence and liver-specific red fluorescence grew normally, and tests of their reproduction ability are currently underway. These data demonstrate that transgene introduction by ICSI-mediated gene transfer into in vitro-matured oocytes is a feasible option for generating pigs expressing fluorescent proteins in a tissue-specific manner.

Essential role of gastric gland mucin in preventing gastric cancer in mice

Gastric gland mucin secreted from the lower portion of the gastric mucosa contains unique O-linked oligosaccharides (O-glycans) having terminal α1,4-linked N-acetylglucosamine residues (αGlcNAc). Previously, we identified human α1,4-N-acetylglucosaminyltransferase (α4GnT), which is responsible for the O-glycan biosynthesis and characterized αGlcNAc function in suppressing Helicobacter pylori in vitro. In the present study, we engineered A4gnt(-/-) mice to better understand its role in vivo. A4gnt(-/-) mice showed complete lack of αGlcNAc expression in gastric gland mucin. Surprisingly, all the mutant mice developed gastric adenocarcinoma through a hyperplasia-dysplasia-carcinoma sequence in the absence of H. pylori infection. Microarray and quantitative RT-PCR analysis revealed upregulation of genes encoding inflammatory chemokine ligands, proinflammatory cytokines, and growth factors, such as Ccl2, Il-11, and Hgf in the gastric mucosa of A4gnt(-/-) mice. Further supporting an important role for this O-glycan in cancer progression, we also observed significantly reduced αGlcNAc in human gastric adenocarcinoma and adenoma. Our results demonstrate that the absence of αGlcNAc triggers gastric tumorigenesis through inflammation-associated pathways in vivo. Thus, αGlcNAc-terminated gastric mucin plays dual roles in preventing gastric cancer by inhibiting H. pylori infection and also suppressing tumor-promoting inflammation.

Poly(A) tail length of neurohypophysial hormones is shortened under endoplasmic reticulum stress

Familial neurohypophysial diabetes insipidus (FNDI) is caused by mutations in the gene locus of arginine vasopressin (AVP), an antidiuretic hormone. Although the carriers are normal at birth, polyuria and polydipsia appear several months or years later. Previously, we made mice possessing a mutation causing FNDI and reported that the mice manifested progressive polyuria as do the patients with FNDI. Here, we report that decreases in AVP mRNA expression in the supraoptic nucleus were accompanied by shortening of the AVP mRNA poly(A) tail length in the FNDI mice, a case in which aggregates accumulated in the endoplasmic reticulum (ER) of the hypothalamic AVP neurons. Expression levels of AVP heteronuclear RNA in the supraoptic nucleus, a sensitive indicator for gene transcription, were not significantly different between FNDI and wild-type mice. Incubation of hypothalamic explants of wild-type mice with ER stressors (thapsigargin and tunicamycin) caused shortening of the poly(A) tail length of AVP and oxytocin mRNA, accompanied by decreases in their expression. On the other hand, an ER stress-reducing molecule (tauroursodeoxycholate) increased the poly(A) tail length as well as the expression levels of AVP and oxytocin mRNA. These data reveal a novel mechanism by which ER stress decreases poly(A) tail length of neurohypophysial hormones, probably to reduce the load of unfolded proteins.

The creation of transgenic pigs expressing human proteins using BAC-derived, full-length genes and intracytoplasmic sperm injection-mediated gene transfer

In most transgenic (Tg) animals created to date, a transgene consisting of the minimum promoter region linked to a cDNA has been used. However, transgenes on small plasmids are susceptible to the position effect, increasing the difficulty of controlling transgene expression. In this study, we attempted to create Tg pigs by intracytoplasmic sperm injection-mediated gene transfer (ICSI-MGT) using two large genomic transgenes derived from a bacterial artificial chromosome (BAC) containing the full genomic region encoding two human proteins, type I collagen and albumin. The production efficiencies (Tg piglets/live offspring) of type I collagen and albumin Tg pigs were 11.8% (6/51) and 18.2% (2/11), respectively. In all of the Tg pigs examined by real-time PCR analysis, tissue-specific expression of the transgene was confirmed (type I collagen: skin, tendon, vessels, genitalia; albumin: liver). The production of human proteins derived from BAC transgenes was also confirmed. Fluorescence in situ hybridization analysis indicated that the BAC transgenes transferred into porcine oocytes by ICSI-MGT were integrated into single or multiple sites on the host chromosomes. These data demonstrate that Tg pigs expressing human proteins in a tissue-specific manner can be created using a BAC transgenic construct and the ICSI-MGT method.

Activation of vasopressin neurons leads to phenotype progression in a mouse model for familial neurohypophysial diabetes insipidus

Familial neurohypophysial diabetes insipidus (FNDI) is a rare disease that is inherited in an autosomal dominant manner. In a previous study, we made a mouse model for FNDI, which showed progressive polyuria accompanied by inclusion bodies in the arginine vasopressin (AVP) neurons formed by aggregates in the endoplasmic reticulum. The present study was conducted to determine whether the activities of AVP neurons are related to the phenotype progression in the FNDI model. In the first experiment, female heterozygous mice were administered either desmopressin (dDAVP) or a vehicle (control) subcutaneously with osmotic minipumps for 30 days. The dDAVP treatment significantly decreased the urine volume, AVP mRNA expression, and inclusion bodies in the AVP neurons. Urine volume in the dDAVP group remained significantly less than the control for 14 days even after the minipumps were removed. In the second experiment, the males were fed either a 0.2% Na or 2.0% Na diet for 6 mo. Urine AVP excretion was significantly increased in the 2.0% Na group compared with the 0.2% Na group for the first 2 mo but gradually decreased thereafter. Throughout the experiments, urine volume increased progressively in the 2.0% Na group but not in the 0.2% Na group. Immunohistochemical analyses revealed that inclusion bodies in the AVP cells had significantly increased in the 2.0% Na compared with the 0.2% Na group. These data demonstrated that activation of AVP neurons could accelerate the aggregate formation as well as the progression of the polyuria in the FNDI model mice.

Polysome trafficking of transcripts and microRNAs in regenerating liver after partial hepatectomy

Liver regeneration after 70% partial hepatectomy (PH) in rats induces >95% of hepatocytes to undergo two rounds of semisynchronous cell replication. Gene expression is controlled primarily by posttranscriptional processing, including changes in mRNA stability. However, the translational activity of a specific mRNA can also be modulated after PH, resulting in significant uncoupling of protein and transcript levels relative to quiescent liver for many genes including c-myc and p53. Although the precise mechanism by which this uncoupling occurs is unknown, the polysomal association of mRNA and microRNA (miRNA) can significantly modulate rate of decay as well as translational activity. Thus we characterized the association of c-myc and p53 mRNAs and miRNAs in free and cytoskeleton- and membrane-bound polysome populations 3, 6, and 24 h after PH. The transcripts for c-myc and p53 were differentially distributed in the three discrete polysome populations, and this was dramatically modulated during liver regeneration. Nascent polysome-associated p53 and c-myc proteins were also differentially expressed in the free and cytoskeleton- and membrane-bound polysomes and significantly uncoupled from transcript levels relative to nonresected liver. At least 85 miRNAs were associated with the three polysome populations, and their abundance and distribution changed significantly during liver regeneration. These data suggest that posttranscriptional control of c-myc and p53 protein expression is associated with the translocation of transcripts between the different polyribosomes. The alteration of expression for the same transcript in different polysome populations may, in part, be due to the action of miRNAs.

Progressive polyuria without vasopressin neuron loss in a mouse model for familial neurohypophysial diabetes insipidus

Familial neurohypophysial diabetes insipidus (FNDI), an autosomal dominant disorder, is mostly caused by mutations in the gene of neurophysin II (NPII), the carrier protein of arginine vasopressin (AVP). Previous studies suggest that loss of AVP neurons might be the cause of polyuria in FNDI. Here we analyzed knockin mice expressing mutant NPII that causes FNDI in humans. The heterozygous mice manifested progressive polyuria as do patients with FNDI. Immunohistochemical analyses revealed that inclusion bodies that were not immunostained with antibodies for mutant NPII, normal NPII, or AVP were present in the AVP cells in the supraoptic nucleus (SON), and that the size of inclusion bodies gradually increased in parallel with the increases in urine volume. Electron microscopic analyses showed that aggregates existed in the endoplasmic reticulum (ER) as well as in the nucleus of AVP neurons in 1-mo-old heterozygous mice. At 12 mo, dilated ER filled with aggregates occupied the cytoplasm of AVP cells, while few aggregates were found in the nucleus. Analyses with in situ hybridization revealed that expression of AVP mRNA was significantly decreased in the SON in the heterozygous mice compared with that in wild-type mice. Counting cells expressing AVP mRNA in the SON indicated that polyuria had progressed substantially in the absence of neuronal loss. These data suggest that cell death is not the primary cause of polyuria in FNDI, and that the aggregates accumulated in the ER might be involved in the dysfunction of AVP neurons that lead to the progressive polyuria.

The endoplasmic reticulum stress-inducible protein Niban regulates eIF2alpha and S6K1/4E-BP1 phosphorylation

The Niban/NIBAN gene is specifically expressed in hereditary renal carcinomas of model animals and in human malignancies, including renal cancers. Although the expression profiles of Niban/NIBAN suggest that it plays an important role in carcinogenesis, no functional information has yet been reported. In this study, we found that the levels of Niban/NIBAN mRNA and protein were induced by treatment with tunicamycin, an inducer of endoplasmic reticulum (ER) stress. To elucidate Niban's in vivo function, we generated a Niban knockout mouse. Niban(-/-) mouse showed no obvious phenotype. Unexpectedly, we found that eukaryotic translational initiation factor (eIF) 2alpha phosphorylation, which is up-regulated during ER stress, was increased in Niban(-/-) cells relative to wild-type control cells. In addition, decreased phosphorylation of p70 ribosomal S6 subunit kinase (S6K) 1 and eukaryotic initiation factor 4E-binding protein (4E-BP) 1 was also detected in Niban(-/-) cells. Similar effects were observed following transfection of NIBAN-specific interfering RNAs in HeLa cells. Thus, Niban positively affects protein translation machineries. Additionally, suppression of NIBAN expression in HeLa cells promoted apoptosis. Together these results suggest that Niban is involved in the ER stress response, and that Niban can modulate cell death signaling by regulating translation.

Development of polyclonal antibodies specific to ATP-binding cassette transporters human ABCG4 and mouse Abcg4: site-specific expression of mouse Abcg4 in brain

In our recent study on seeking new mouse ATP-binding cassette (ABC) transporters of the G subfamily, we succeeded in cloning mouse Abcg4 from a cDNA library of mouse brain, and we characterized the tissue-specific expression and chromosomal localization of the mouse Abcg4 gene. To further characterize the physiological function of mouse Abcg4 protein and to compare its function with that of ABCG2, in the present study, we developed polyclonal antibodies against mouse Abcg4 and established the Abcg4-expression system. To raise antibodies, we selected three different epitope peptides that correspond to the amino acid residues of 46-60, 465-479, and 600-613 in mouse Abcg4 protein. The antibody raised against the epitope encoding the amino acids 46-60 was found to be specific to mouse Abcg4, exhibiting a band with molecular weight of 63,000 on immunoblotting, whereas this band was dose-dependently diminished by adding the corresponding epitope peptide into the immunoblot medium. Use of the antibody for immunoblot detection in mouse normal tissues revealed that the Abcg4 protein is expressed in brain, spleen, and testis. Immunohistochemical studies showed that mouse Abcg4 is site-specifically expressed in the cerebral cortex and medulla of mouse brain. These results suggest that mouse Abcg4 plays a certain physiological role in the brain. It is of importance to note that the sequence of amino acids 46-60 is completely identical between mouse Abcg4 and human ABCG4. Thus, this antibody is applicable to the detection of human ABCG4 as well as mouse Abcg4.

A deleted form of human hepatocyte growth factor stimulates hepatic lipogenesis and lipoprotein synthesis in rats

Here we report the effect of the recombinant human deleted form of hepatocyte growth factor (dHGF) on lipid metabolism in rats. In primary cultured rat hepatocytes, dHGF accelerated incorporation of [(14)C]acetate into cellular lipids in a concentration-dependent manner. dHGF also increased the gene expression and enzyme activity of glucose-6-phosphate dehydrogenase, a rate-limiting enzyme of the pentose phosphate pathway, in hepatocytes. These results suggest that dHGF stimulates hepatocyte lipogenesis through upregulation of the pentose pathway and NADPH formation. Injection of dHGF into normal rats induced elevation of the serum triglyceride, phospholipid and cholesterol levels dose-dependently and in the same time course as the liver growth. dHGF injections stimulated the [(14)C]acetate incorporation into the liver lipids, but not into the adipose tissue nor the small intestine. Serum very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels were elevated by dHGF injections. [(14)C]Leucine incorporation into VLDL and LDL was also increased by dHGF injections. In rats with alcohol-induced fatty livers, dHGF treatment markedly diminished the accumulated liver triglyceride, while elevating serum lipid concentrations. The present results indicate that dHGF stimulates exclusively hepatic lipogenesis and increases serum lipoprotein levels in rats.

Tri-iodothyronine and a deleted form of hepatocyte growth factor act synergistically to enhance liver proliferation and enable in vivo retroviral gene transfer via the peripheral venous system

Retroviral vectors integrate into the target cell genome in a stable manner and therefore offer the potential for permanent correction of the genetic diseases that affect the liver. These vectors, however, usually require cell division to occur in order to allow provirus entry into the nucleus. We have explored clinically acceptable methods to improve the efficiency of retroviral gene transfer to the liver, which avoid the need for liver damage. Tri-iodothyronine (T3) and recombinant hepatocyte growth factor have previously been used to induce hepatocyte proliferation in rat livers and allow in vivo retroviral gene transfer. We investigated the combined effects of these growth factors, with their differing mechanisms of action, on hepatocyte proliferation in vivo and assessed their effectiveness in priming cells for retroviral gene transfer. During the phase of hepatocyte proliferation retrovirus was administered via either the portal or tail vein. Acting synergistically, T3 and a truncated form of recombinant hepatocyte growth factor (dHGF) induced 30% of hepatocytes in normal rat liver to enter DNA synthesis at 24 h. This increased proliferation enabled the liver to be transduced in vivo by retroviral vectors via either the portal or peripheral venous system, achieving transduction efficiencies of 6.9 +/- 1.6% and 4.3 +/- 0.4% respectively. Thus, the liver can be simply and conveniently transduced in vivo with integrating vectors, introduced via the peripheral venous system during a wave of growth factor-induced proliferation, pointing the way to clinically applicable gene transfer techniques.

Sequence analysis of RNA-2 of different isolates of broad bean wilt virus confirms the existence of two distinct species

The complete nucleotide sequence of RNA-2 from a Japanese isolate IP of broad bean wilt virus (BBWV) was determined. The sequence encodes a single large polyprotein, which contains a putative movement protein and two coat proteins (CPs). The 3'-terminal sequences of RNA-2 were also determined for three other Japanese isolates and two ATCC isolates (PV132 and PV176) of BBWV. The CPs of the four Japanese isolates share 86.8-98.0% amino acid sequences homology with one another and 88.3-96.5% with those reported for the isolate PV131 (BBWV-2). However, they have only 57.9-66.2% homology with those of PV132 and PV176 (BBWV-1).

Effects of the deleted form of hepatocyte growth factor on serum hyaluronate levels in rats with liver cirrhosis

Effects of the deleted form of hepatocyte growth factor (dHGF) on serum hyaluronate levels, an index for liver cirrhosis, were studied in rats. The levels of serum hyaluronate increased in rats with dimethylnitrosamine- or carbontetrachloride-induced cirrhotic liver with prolongation of prothrombin time, which indicates disorder of liver function. Daily intravenous injection of dHGF reduced the elevated serum hyaluronate levels with improvement of the prolonged prothrombin time. These results suggest that the amelioration of hepatic function disorder by dHGF leads to a reduction of the increased serum hyaluronate levels.

Preventive effects of the deleted form of hepatocyte growth factor against various liver injuries

The effects of a naturally occurring deleted form of hepatocyte growth factor (HGF) on hepatic disorder were studied in various models of hepatic failure. The pretreatment of rats and mice with the deleted form of HGF prevented the liver injuries and coagulopathy induced by endotoxin, dimethylnitrosamine and acetaminophen and reduced the mortality due to hepatic dysfunction induced by these hepatotoxins. The concurrent administration of the deleted form of HGF also prevented the liver injury and hepatic fibrosis in mice treated with alpha-naphthylisothiocyanate and in rats treated with dimethylnitrosamine. Moreover, the deleted form of HGF normalized the results of the bromosulphalein-clearance test and ameliorated jaundice in rats with periportal cholangiolitic hepatopathy induced by alpha-naphthylisothiocyanate. The deleted form of HGF also reversed the coagulopathy in rats with hepatic disorder induced by dimethylnitrosamine or by 70% resection of cirrhotic liver (induced by carbon tetrachloride). In Long Evans cinnamon rats receiving vehicle, 20 out of 21 animals died within 4 days after the onset of jaundice. After infusion of the deleted form of HGF for 4 days, 7 out of 20 Long-Evans cinnamon rats survived. These results indicate that the deleted form of HGF could have therapeutic potency in patients with severe hepatic failure.

Deleted form of hepatocyte growth factor (dHGF) increases the number of platelets in rats with liver cirrhosis

The effect of the deleted form of hepatocyte growth factor (dHGF) on thrombopoiesis was studied in rats. When normal rats were injected with dHGF (0.5 mg/kg i.v. twice a day), the number of platelets increased to about 1.5-fold the initial level. In addition, the treatment with dHGF (0.5 mg/kg i.v. twice daily) significantly increased the number of platelets in rats with liver cirrhosis induced by carbon tetrachloride and phenobarbital. When dHGF was given to rats at a dose of 0.05 or 0.5 mg/kg from the beginning of the induction of dimethylnitrosamine liver cirrhosis to day 28, dHGF dose-dependently ameliorated thrombocytopenia and completely prevented it at a dose of 0.5 mg/kg. These results indicate that dHGF may be applicable to the treatment of thrombocytopenia associated with liver cirrhosis.

Identification of casoxin C, an ileum-contracting peptide derived from bovine kappa-casein, as an agonist for C3a receptors

Casoxin C (Tyr-Ile-Pro-Ile-Gln-Tyr-Val-Leu-Ser-Arg) is a bioactive peptide that was isolated from a tryptic digest of bovine kappa-casein as an anti-opioid peptide in longitudinal strips of guinea pig ileum. Casoxin C also evokes contraction of the ileal strips, and we found that this process was biphasic with rapid and slow components. The contractile profile was very similar to that of human complement C3a(70-77), which is the COOH-terminal octapeptide of C3a and has, although less potent, qualitatively the same biological activities as C3a. Casoxin C also has homology with C3a(70-77). The rapid contraction was mediated by histamine release and the slow contraction was mediated by a prostaglandin E2-like substance, judging from the effects of various pharmacological inhibitors and antagonists on the ileal contraction. Casoxin C had affinity for C3a receptors (IC50 = 40 microM) in the radioreceptor assay. In addition, casoxin C showed phagocyte-stimulating activities. Casoxin C is therefore the first milk-derived peptide identified, that acts through complement C3a receptors.

Antifibrogenic effect of a deletion variant of hepatocyte growth factor on liver fibrosis in rats

Hepatic fibrosis, which may lead to cirrhosis, is associated with most chronic liver diseases. Current therapies for hepatic fibrosis are, however, generally ineffective. In this report we assessed the efficacy of the treatment of hepatic fibrosis with a naturally occurring deletion variant of hepatocyte growth factor (dHGF). The administration of dHGF increased liver weight and suppressed the increase of hepatic collagen content in rats treated with dimethylnitrosamine (DMN) to induce hepatic fibrosis. Furthermore, dHGF exerted its mitogenic and antifibrogenic activities even after the liver fibrosis had been established with DMN. Northern blot analysis showed that dHGF suppressed the increase of messenger RNA (mRNA) levels of procollagen alpha 2(I), alpha l(III), alpha 1(IV), transforming growth factor beta 1 (TGF-beta1), desmin (a marker of hepatic lipocytes), and alpha-smooth muscle (sm)-actin (a marker of activated hepatic lipocytes). In addition to suppressing the elevated TGF-beta1, mRNA level in hepatic fibrosis, dHGF had a potent ability to decrease TGF-beta1 mRNA level even in a normal liver. Immunohistochemical analysis revealed that desmin-positive cells and alpha-sm-actin-positive cells were increased in the hepatic fibrosis, whereas neither cells were seen in livers of DMN-treated rats given dHGF. We conclude that dHGF prevents and improves the DMN-induced hepatic fibrosis in rats by reducing mRNA levels of procollagens and TGF-beta1, by inhibiting an activation of hepatic lipocytes, and by stimulating liver regeneration. dHGF may be useful for and applicable to the treatment of fibrosis in chronic liver diseases.

Amelioration of disordered hepatic protein synthesis by the deleted form of hepatocyte growth factor in models of liver failure in rats

Because the liver plays an important role in protein synthesis and cholesterol metabolism and reductions in these functions are observed in almost all hepatic disorders, the effects of the deleted form of hepatocyte growth factor (dHGF) on disordered hepatic protein synthesis were studied in various liver-injured rat models using Wistar male rats. In the 70% hepatectomized rats, plasma clotting time was prolonged and the serum level of total protein and the liver protein content were decreased. The treatment of the animals with dHGF (100-500 micrograms kg-1, i.v., twice daily) ameliorated these parameters at 48 or 72 h. The administration of carbon tetrachloride or D-galactosamine to hepatectomized rats induced a marked prolongation of plasma clotting time and hypoproteinaemia. In the animals treated with dHGF (500 micrograms kg-1, i.v., twice daily) these parameters were rapidly reversed compared with those of control groups. In a hepatocellular necrosis model induced by dimethylnitrosamine, the plasma clotting time was extremely prolonged, and liver protein content, serum total protein, albumin, HDL-cholesterol (as an index of lipoprotein) and plasma lecithin-cholesterol acyltransferase activity severely reduced. In this severely injured model, dHGF (5-500 micrograms kg-1, i.v., twice daily for 28 days) dose-dependently prevented the loss of liver protein content and improved the disordered plasma coagulability and serum protein levels. These results suggest that dHGF is useful for ameliorating the disorders in hepatic functions such as protein synthesis.

[Clinical usefulness of GnRH agonist therapy for premenopausal women with uterine leiomyoma]

The purpose of this study was to evaluate the tumor volume reducing effect and the frequency with which menopause is induced in premenopausal women with leiomyoma uteri treated with GnRHa buserelin, 900 micrograms/day for 24 weeks. Twenty-six women, whose average age was 49.7 +/- 2.1 years (Mean +/- SD), were enrolled in this study. Uterine and myoma volume were measured by computed tomography (CT) and transvaginal sonography, respectively. Mean uterine and myoma volume had decreased by 33.7% and 39.9%, respectively at 24 weeks of GnRHa therapy. Nine patients were brought to menopause following the treatment. This rate (34.6%) is significantly higher than that of the age matched control group (11.8%), at eighteen months' observation without GnRHa treatment. We conclude that GnRHa treatment for premenopausal women with uterine leiomyoma causes not only temporary ovarian suppression but also has a strong tendency to induce menopause.

Mixed mesodermal tumor of the ovary: immunohistochemical study with histogenetic consideration

The clinical, histological and immunohistochemical features of three cases of ovarian mixed mesodermal tumor (MMT) were examined. The epithelial component was serous papillary cystadenocarcinoma in case 1 and 3, and endometrioid adenocarcinoma in case 2. In case 1, undifferentiated adenocarcinoma was also seen. The mesenchymal component was fibrosarcomatous and chondrosarcomatous in case 1 and 2. In case 3, only fibrosarcomatous area was seen. No endometriosis was observed. Immunohistochemically, the epithelial component showed positivity for epithelial membrane antigen in all three cases. S-100 protein was positive in two cases with chondrosarcomatous differentiation. The fibrosarcomatous area showed positivity for vimentin in all three cases. However desmin, myosin and myoglobin were negative. The antibodies thought to be epithelial or mesenchymal markers unexpectedly reacted positively in some cells; for example, EMA was positive in fibrosarcomatous and chondrosarcomatous cells. Therefore, it was speculated that because the undifferentiated tumor cells had a biphasic character, MMT might originate from immature multipotential cells of surface epithelium and subcapsular connective tissue of the ovary.

[MHC class I antigen expression by molar trophoblast]

It is an issue for debate why molar tissues are not rejected by an immunologically potent host, since all genes in complete moles and 2/3 genes in partial moles are considered to be paternally derived. Molar trophoblasts are in direct contact with host cells, and therefore HLA expression by these cells may hold the key to the elucidation of the immunological reaction between molar tissues and the host. It has been reported that villous trophoblasts are negative and extravillous trophoblasts are positive for HLA-A, B,C, but the expressed HLA-A,B,C molecule has been noted to lack their polymorphic determinants. We analyzed the reactivity of two monoclonal antibodies to a monomorphic determinant of HLA-A,B,C (W6/32 and Cappel anti-HLA-A,B,C) with molar trophoblasts, using three uteri containing complete moles and two containing partial moles. The reactivity was examined by an indirect immunoperoxidase method. The staining patterns were almost identical in complete moles and partial moles. Villous trophoblasts showed a negative reaction with both antibodies. On the other hand, extravillous trophoblasts exhibited intense staining for W6/32 and negative staining for Cappel anti-HLA-A,B,C, which may suggest that the expression of a constant region as well as a variant region of HLA-A,B,C molecule is incomplete.

[Cytomorphological reappraisal of choriocarcinoma cells--a proposal of a four cell pattern]

It is generally accepted that choriocarcinoma is composed of two cell types: syncytiotrophoblast (ST)-like cells and cytotrophoblast (CT)-like cells. In normal and molar pregnancy, there is another population of trophoblast in the cell column, the decidua and so forth. They are designated intermediate trophoblast (IT) and multinuclear IT. It remains to be clarified whether IT-like cells and multinuclear IT-like cells are observed in choriocarcinoma. In the present study, choriocarcinoma cells were reappraised cytomorphologically in three cases of uterine choriocarcinoma and additional three cases of metastatic choriocarcinoma. The results were as follows: 1. Choriocarcinoma cells could be classified into four cell types: ST-like cells, CT-like cells, IT-like cells and multinuclear IT-like cells. 2. IT-like cells predominated in metastatic lesions as compared with primary lesions. It seemed that choriocarcinoma shows both differentiations which take place in villous and extravillous trophoblasts of normal and molar pregnancy. IT-like cells were found to infiltrate into vessel walls, which, together with the predominance of IT-like cells in metastatic lesions, suggests that IT-like cells contribute greatly to the hematogenous metastasis in choriocarcinoma. The presence of ST-like cells, CT-like cells and multinuclear IT-like cells in metastatic lesions may indicate a germinative nature of IT-like cells.

Amino acid neurotransmitters in iron-induced epileptic foci of rats

Injection of iron salts into the rodent cortex has been shown to cause chronic or recurrent seizures. Amino acid levels in the cerebral cortex were examined 1, 3, 6, 9, 24, 48 hours and 4 weeks after an injection of ferric chloride solution to the left sensory motor cortex of rats. Aspartate level decreased 9 and 24 hours after the injections with ferric chloride. No significant change was observed in glutamate level, though glutamine level decreased 3 and 48 hours after the injection. GABA level decreased 6 hours after the injection. On the contrary, alanine and glycine levels increased 1 and 24 hours, and 24 hours after the injection, respectively. These results suggest that these amino acid neurotransmitters are involved in the acute seizure mechanism and in the process of chronic focus formation in the iron-induced epilepsy of rats.

Esophagocardioplasty with gastric patch in the treatment of achalasia

Result of operative treatment in 196 cases of achalasia was reviewed. The procedures employed include cardiolysis, Heller's extramucosal myotomy, Wendel's cardioplasty, Heyrovsky's esophagocardiostomy, with and without pyloroplasty, cardiac resection and esophagocardioplasty with gastric patch. Follow-up study on 166 cases revealed that the result was classified as good in 99 cases or 59.6 per cent and improved in 46 cases or 27.7 per cent. Overall satisfactory result was obtained in 87.3 per cent. When the result was broken down to groups following three classifications, i.e. according to X-ray, endoscopic and manometric findings, the interesting correlation emerged. Heller's myotomy and esophagocardioplasty with gastric patch gave best results in early stage of achalasia, while in later stage the latter procedure seems to be the operation of choice.

Relationships between Chemical Structures of Crosslink Sites and Physical Properties of Vulcanized Rubbers. Part V. Analysis of Chemical Structures of Combined Sulfur in Crosslink Sites for Various EPDM Vulcanizates

Various EPDM vulcanizates with different chemical structures of crosslink sites, such as C—C, C—R—C and C—Sz—C linkage, were obtained by using a variety of curing agents. C—Sz—C linkage was separated into polysulfide linkage and monosulfide linkage by using the LiAlH4 method which was confirmed beforehand with model compounds. The relationships between the chemical structure of combined sulfur in the crosslink sites and the type of curing agents used were clarified. For example, the mole ratios of polysulfide linkage to all the combined sulfurs in the vulcanizates by using DCP—S8, TMTD, S8—TMTD and S8-zinc dimethyldithiocarbamate curing system were respectively 0.35, 0.25, 0.53 and 0.82 at 160° C for 45 minutes. But in DCP—S8 curing system considerable C—C linkages seemed to be formed in addition to the C—Sz—C linkage.

Relationships between Chemical Structures of Crosslink Sites and Physical Properties of Vulcanized Rubbers. Part VI. Oxidative Degradation of EPDM Vulcanizates

Relationship between the chemical structures of crosslinks and the degree of oxidative degradation of EPDM vulcanizates was studied by stress relaxation and oxygen absorption measurements. It was found that the vulcanizates having C—Sx—C crosslink showed slower stress relaxation than the vulcanizate having other crosslink structures, i.e., C—S—C, C—C, and C—R—C. It was thought that C—Sx—C bond would reduce the scission of the network in oxidative degradation, since some polysulfide compounds had the same effect of protecting scission as antioxidant. The similar results were obtained in oxygen absorption measurements. In the case of heat aging, the vulcanizate having C—Sx—C linkage increased in crosslinks during aging and the rate of crosslinking was equal to the rate of scission of the network in the early stages, but the vulcanizates having other types of crosslinks did not show such behavior.