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Naive human induced pluripotent stem cells (iPSCs) can be generated by reprogramming somatic cells with Sendai virus (SeV) vectors. However, only dermal fibroblasts have been successfully reprogrammed this way, and the process requires culture on feeder cells. Moreover, SeV vectors are highly persistent and inhibit subsequent differentiation of iPSCs. Here, we report a modified SeV vector system to generate transgene-free naive human iPSCs with superior differentiation potential. The modified method can be applied not only to fibroblasts but also to other somatic cell types. SeV vectors disappear quickly at early passages, and this approach enables the generation of naive iPSCs in a feeder-free culture. The naive iPSCs generated by this method show better differentiation to trilineage and extra-embryonic trophectoderm than those derived by conventional methods. This method can expand the application of iPSCs to research on early human development and regenerative medicine., 優れた多分化能を持つヒトのナイーブ型iPS細胞を迅速に作製する方法を発明. 京都大学プレスリリース. 2022-10-18., A novel method for generating naive human iPS cells with significantly higher differentiation potency. 京都大学プレスリリース. 2022-11-15.

Lysophospholipids (LPLs) are small bioactive lipid molecules characterized by a single carbon chain and a polar head group. LPLs have recently shown to be involved in many physiological and pathological processes such as nervous system regulation. In our previous studies, a porcine liver decomposition product (PLDP) has been identified as a substance that improves cognitive function at old ages. This PLDP is a rich source of LPLs, including lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE). This study was designed to evaluate the anti-inflammatory effect of these LPLs on lipopolysaccharide (LPS)-stimulated SIM-A9 microglial cells in terms of cytokine expression and oxidative stress and to investigate the potential mechanisms underlying these effects. SIM-A9 cells were pretreated with LPLs prior to LPS stimulation, and the anti-inflammatory potential of the LPLs in LPS-induced SIM-A9 cells was examined. Pretreatment with LPLs significantly inhibited the LPS-induced expression of IL-6 in SIM-A9 cells. Furthermore, oxidative-related protein, NADPH oxidase 2 (Nox2) levels were markedly increased in the LPS-treated cells, and pretreatment with LPC and LPE significantly reduced to basal levels. In addition, LPS-induced ROS production was eliminated in apocynin-treated cells, indicating that ROS production was dependent on Nox2. Our findings revealed that pretreatment with LPC and LPE decreased LPS-stimulated ROS production. These results indicated that LPC and LPE exerted significant protective effects against LPS-induced inflammation and oxidative stress in SIM-A9 cell.

Background. We report the first-in-human safety and immunogenicity assessment of a prototype intranasally administered, replication-competent Sendai virus (SeV)–vectored, human immunodeficiency virus type 1 (HIV-1) vaccine. Methods. Sixty-five HIV-1–uninfected adults in Kenya, Rwanda, and the United Kingdom were assigned to receive 1 of 4 prime-boost regimens (administered at 0 and 4 months, respectively; ratio of vaccine to placebo recipients, 12:4): priming with a lower-dose SeV-Gag given intranasally, followed by boosting with an adenovirus 35–vectored vaccine encoding HIV-1 Gag, reverse transcriptase, integrase, and Nef (Ad35-GRIN) given intramuscularly (SLA); priming with a higher-dose SeV-Gag given intranasally, followed by boosting with Ad35-GRIN given intramuscularly (SHA); priming with Ad35-GRIN given intramuscularly, followed by boosting with a higher-dose SeV-Gag given intranasally (ASH); and priming and boosting with a higher-dose SeV-Gag given intranasally (SHSH). Results. All vaccine regimens were well tolerated. Gag-specific IFN-γ enzyme-linked immunospot–determined response rates and geometric mean responses were higher (96% and 248 spot-forming units, respectively) in groups primed with SeV-Gag and boosted with Ad35-GRIN (SLA and SHA) than those after a single dose of Ad35-GRIN (56% and 54 spot-forming units, respectively) or SeV-Gag (55% and 59 spot-forming units, respectively); responses persisted for ≥8 months after completion of the prime-boost regimen. Functional CD8+ T-cell responses with greater breadth, magnitude, and frequency in a viral inhibition assay were also seen in the SLA and SHA groups after Ad35-GRIN boost, compared with those who received either vaccine alone. SeV-Gag did not boost T-cell counts in the ASH group. In contrast, the highest Gag-specific antibody titers were seen in the ASH group. Mucosal antibody responses were sporadic. Conclusions. SeV-Gag primed functional, durable HIV-specific T-cell responses and boosted antibody responses. The prime-boost sequence appears to determine which arm of the immune response is stimulated. Clinical Trials Registration. {"type":"clinical-trial","attrs":{"text":"NCT01705990","term_id":"NCT01705990"}}NCT01705990.

Cytotoxic T lymphocyte (CTL) responses play a central role in viral suppression in human immunodeficiency virus (HIV) infections. Prophylactic vaccination resulting in effective CTL responses after viral exposure would contribute to HIV control. It is important to know how CTL memory induction by vaccination affects postexposure CTL responses. We previously showed vaccine-based control of a simian immunodeficiency virus (SIV) challenge in a group of Burmese rhesus macaques sharing a major histocompatibility complex class I haplotype. Gag 206-216 and Gag 241-249 epitope-specific CTL responses were responsible for this control. In the present study, we show the impact of individual epitope-specific CTL induction by prophylactic vaccination on postexposure CTL responses. In the acute phase after SIV challenge, dominant Gag 206-216 -specific CTL responses with delayed, naive-derived Gag 241-249 -specific CTL induction were observed in Gag 206-216 epitope-vaccinated animals with prophylactic induction of single Gag 206-216 epitope-specific CTL memory, and vice versa in Gag 241-249 epitope-vaccinated animals with single Gag 241-249 epitope-specific CTL induction. Animals with Gag 206-216 -specific CTL induction by vaccination selected for a Gag 206-216 -specific CTL escape mutation by week 5 and showed significantly less decline of plasma viral loads from week 3 to week 5 than in Gag 241-249 epitope-vaccinated animals without escape mutations. Our results present evidence indicating significant influence of prophylactic vaccination on postexposure CTL immunodominance and cooperation of vaccine antigen-specific and non-vaccine antigen-specific CTL responses, which affects virus control. These findings provide great insights into antigen design for CTL-inducing AIDS vaccines.

MazF is an Escherichia coli toxin that is highly conserved among the prokaryotes and plays an important role in growth regulation. When MazF is induced, protein synthesis is effectively inhibited. However, the mechanism of MazF action has been controversial. Here we unequivocally demonstrate that MazF is an endoribonuclease that specifically cleaves mRNAs at ACA sequences. We then demonstrate its enzymatic specificity using short RNA substrates. MazF cleaves RNA at the 5'-end of ACA sequences, yielding a 2',3'-cyclic phosphate at one side and a free 5'-OH group at the other. Using DNA-RNA chimeric substrates containing XACA, the 2'-OH group of residue X was found absolutely essential for MazF cleavage, whereas all the other residues may be deoxyriboses. Therefore, MazF exhibits exquisite site specificity and has utility as an RNA-restriction enzyme for RNA structural studies or as an mRNA interferase to regulate cell growth in prokaryotic and eukaryotic cells.

Gag p19 protein (MA) of the transformation-defective Rous sarcoma virus mutant, tdPH2010, has a point mutation at nucleotide 376 (G to A) that results in an amino-acid change at residue 126 of p19 (Glu to Lys). This single amino-acid change is the cause of the aberrantly fast migration of this protein on SDS-polyacrylamide gels. To study the biological significance of the mutation, we introduced this mutation into a transformation-defective derivative of the molecularly cloned Rous sarcoma virus, SRA2, and examined its effect on virus replication. The virus possessing the mutation in its gag p19 gene had 50% slower replication as measured by the amount of reverse transcriptase as well as gag p27 protein (CA) in the culture media. Glu at position 126 appears to be important for efficient production of Rous sarcoma virus in vitro.

HIV-1 RNA dimerization involves at least two key regions, one located upstream from the splice donor (SD) site, and the other located downstream from the SD site. To determine the precise location and the mechanism of action of the downstream region, we constructed a model system using a synthetic HIV-1 RNA fragment (HXB2, 455-1146), which dimerized at relatively low salt concentrations (100 mM KCl, 1 mM MgCl2). We tested in this system antisense DNAs that are complementary to both the upstream and downstream regions of HIV-1 RNA for their possible inhibitory effects on dimerization. Antisense DNAs complementary to nucleotides 773-789 located downstream from the SD site effectively inhibited dimerization of HIV-1 RNA. These inhibitory antisense DNAs hybridized with the dimer form of HIV-1 RNA, and dissociated the dimer into monomers. However, antisense DNAs complementary to the region upstream from the SD site did not hybridize with the dimer, although they inhibited RNA dimerization and also dissociated the preformed dimer.

The molecular basis of the cytopathic effects (CPE) of the transformation-defective avian retrovirus mutant, tdPH2010, was studied. tdPH2010 is a subgroup A virus isolated from the Schmidt-Ruppin (NY) subgroup A strain (SRA(NY)). Subgroup A avian retroviruses are generally considered noncytopathic. Integrated tdPH2010 was molecularly cloned from infected quail cells. A noncytopathic, transformation-defective control strain, BSU, was created by deleting the src gene from the molecularly cloned wild type SRA(NY) virus. Chimeras between tdPH2010 and BSU were constructed and viruses were recovered from transfected chick embryo fibroblasts. Growth curves of cells infected with chimeric viruses indicated that the long terminal repeat (LTR) of tdPH2010 converts BSU to a cytopathic virus. Nucleotide sequencing revealed two point mutations unique to tdPH2010 in the U3 region of LTR at positions –126 and –23 from the transcription start site. Both mutations were located inside or near the promoter/enhancer elements of U3. The mutation at –126 (G to T) converted one of the very well-conserved pentanucleotide repeat (PRE) motifs from GGTGG to GGTGT. The other at –23 (G to A) is located next to the TATA box. The G at this position is conserved in all other known avian retrovirus promoters.

Halogenated gomisin J (a derivative of lignan compound), represented by the bromine derivative 1506 [(6R, 7S, S-biar)-4,9-dibromo-3,10-dihydroxy-1,2,11,12-tetramethoxy-6, 7-dimethyl-5,6,7,8- tetrahydrodibenzo[a,c]cyclo-octene], was found to be a potent inhibitor of the cytopathic effects of human immunodeficiency virus type 1 (HIV-1) on MT-4 human T cells (50% effective dose, 0.1 to 0.5 microM). Gomisin J derivatives were active in preventing p24 production from acutely HIV-1-infected H9 cells. The selective indices (toxic dose/effective dose) of these compounds were as high as > 300 in some systems. 1506 was active against 3'-azido-3'-deoxythymidine-resistant HIV-1 and acted synergistically with AZT and 2',3'-ddC. 1506 inhibited HIV-1 reverse transcriptase (RT) in vitro but not HIV-1 protease. From the time-of-addition experiment, 1506 was found to inhibit the early phase of the HIV life cycle. A 1506-resistant HIV mutant was selected and shown to possess a mutation within the RT-coding region (at position 188 [Tyr to Leu]). The mutant RT expressed in Escherichia coli was resistant to 1506 in the in vitro RT assay. Some of the HIV strains resistant to other nonnucleoside HIV-1 RT inhibitors were also resistant to 1506. Comparison of various gomisin J derivatives with gomisin J showed that iodine, bromine, and chlorine in the fourth and ninth positions increased RT inhibitory activity as well as cytoprotective activity.

Induction of durable cellular immune responses by vaccination is an important strategy for the control of persistent pathogen infection. Viral vectors are promising vaccine tools for eliciting antigen-specific T-cell responses. Repeated vaccination may contribute to durable memory T-cell induction, but anti-vector antibodies could be an obstacle to its efficacy. We previously developed a Sendai virus (SeV) vector vaccine and showed the potential of this vector for efficient T-cell induction in macaques. Here, we examined whether repeated SeV vector vaccination with short intervals can enhance antigen-specific CD8(+) T-cell responses. Four rhesus macaques possessing the MHC-I haplotype 90-120-Ia were immunized three times with intervals of three weeks. For the vaccination, we used replication-defective F-deleted SeV vectors inducing CD8(+) T-cell responses specific for simian immunodeficiency virus Gag(206-216) and Gag(241-249), which are dominant epitopes restricted by 90-120-Ia-derived MHC-I molecules. All four animals showed higher Gag(206-216)-specific and Gag(241-249)-specific CD8(+) T-cell responses after the third vaccination than those after the first vaccination, indicating enhancement of antigen-specific CD8(+) T-cell responses by the second/third SeV vector vaccination even with short intervals. These results suggest that repeated SeV vector vaccination can contribute to induction of efficient and durable T-cell responses.

In the present study, a direct selective thrombin inhibitor, argatroban, and an indirect non-selective inhibitor, heparin, were examined for the inhibitory effect on factor Xa-induced platelet aggregation. Platelet aggregation was induced by thrombin or factor Xa+prothrombin in the presence of Ca++ using rabbit gelfiltered platelets. IC50 of argatroban on factor Xa-induced aggregation was 5–7 times higher than that on thrombin-induced aggregation, while IC50 of heparin in the presence of antithrombin III on factor Xa-induced aggregation was 90–200 times higher than that on thrombin-induced aggregation. This finding suggests that argatroban inhibits thrombin generating on the platelet surface more efficiently than heparin, and this may be one of the reasons for the higher efficacy of argatroban in arterial thrombosis as compared with heparin.

Newly prepared phosphatidylethanolamine (PE) conjugates of glycosaminoglycans can be immobilized to solid phase through hydrophobic interaction. Primary rat hepatocytes were cultured on type I collagen or laminin substrates containing heparin-PE and assayed for DNA synthesis initiated by hepatocyte growth factor (HGF). Hepatocytes responded to HGF that had been added to culture media by active DNA synthesis and pronounced cell spreading, regardless of the presence of heparin-PE on the substrates. The preincubation with HGF, but not with epidermal growth factor, of the substrates containing heparin-PE significantly enhanced DNA synthesis and cell spreading in the absence of these mitogens in culture media. The enhancements were abolished by omitting heparin-PE or washing the HGF-treated substrates with 1 M NaCl, suggesting the immobilization of HGF to substrates through heparin. These phenomena were more evident with laminin substrates than with type I collagen substrates. Chondroitin sulfate-PE only partly substituted for heparin-PE, but Matrigel gave results similar to those of the substrates containing heparin-PE. Both type I collagen and laminin substrates containing heparin-PE bound higher amounts of HGF than the respective control substrates, whereas neither of the substrates containing chondroitin sulfate-PE did. However, the increase in HGF binding to the substrates was not as evident as the increase in DNA synthesis, suggesting that the latter is not simply due to the former but due to a concerted action of the immobilized HGF and heparin. Taken together, these results suggest that HGF can be trapped in extracellular matrix, probably through heparan sulfate in vivo, thereby acting as a mitogen for hepatocytes in cooperation with heparan sulfate.

Viral vectors are promising vaccine tools for eliciting potent cellular immune responses. Pre-existing anti-vector antibodies, however, can be an obstacle to their clinical use in humans. We previously developed a Sendai virus (SeV) vector vaccine and showed the potential of this vector for efficient CD8 + T-cell induction in macaques. Here, we investigated the immunogenicity of SeV vector vaccination in the presence of anti-SeV antibodies. We compared antigen-specific CD8 + T-cell responses after intranasal or intramuscular immunization with a lower dose (one-tenth of that in our previous studies) of SeV vector expressing simian immunodeficiency virus Gag antigen (SeV-Gag) between naive and pre-SeV-infected cynomolgus macaques. Intranasal SeV-Gag immunization efficiently elicited Gag-specific CD8 + T-cell responses not only in naive but also in pre-SeV-infected animals. In contrast, intramuscular SeV-Gag immunization induced Gag-specific CD8 + T-cell responses efficiently in naive but not in pre-SeV-infected animals. These results indicate that both intranasal and intramuscular SeV administrations are equivalently immunogenic in the absence of anti-SeV antibodies, whereas intranasal SeV vaccination is more immunogenic than intramuscular in the presence of anti-SeV antibodies. It is inferred from a recent report investigating the prevalence of anti-SeV antibodies in humans that SeV-specific neutralizing titers in more than 70% of people are no more than those at the SeV-Gag vaccination in pre-SeV-infected macaques in the present study. Taken together, this study implies the potential of intranasal SeV vector vaccination to induce CD8 + T-cell responses even in humans, suggesting a rationale for proceeding to a vaccine clinical trial using this vector.

Cytotoxic T lymphocyte (CTL) responses are crucial for the control of human and simian immunodeficiency virus (HIV and SIV) replication. A promising AIDS vaccine strategy is to induce CTL memory resulting in more effective CTL responses post-viral exposure compared to those in natural HIV infections. We previously developed a CTL-inducing vaccine and showed SIV control in some vaccinated rhesus macaques. These vaccine-based SIV controllers elicited vaccine antigen-specific CTL responses dominantly in the acute phase post-challenge. Here, we examined CTL responses post-challenge in those vaccinated animals that failed to control SIV replication. Unvaccinated rhesus macaques possessing the major histocompatibility complex class I haplotype 90-088-Ij dominantly elicited SIV non-Gag antigen-specific CTL responses after SIV challenge, while those induced with Gag-specific CTL memory by prophylactic vaccination failed to control SIV replication with dominant Gag-specific CTL responses in the acute phase, indicating dominant induction of vaccine antigen-specific CTL responses post-challenge even in non-controllers. Further analysis suggested that prophylactic vaccination results in dominant induction of vaccine antigen-specific CTL responses post-viral exposure but delays SIV non-vaccine antigen-specific CTL responses. These results imply a significant influence of prophylactic vaccination on CTL immunodominance post-viral exposure, providing insights into antigen design in development of a CTL-inducing AIDS vaccine.

We investigated the effect of a new antiplatelet agent, MCI-9042 «±)-2-(dimethyl­ amino )-1-[[ o-(m-methoxyphenethyl)phenoxy ]methyl]ethyl hydrogen succinate) on the deformability of red blood cells (RBC deformability). In the ftltration tests with whole blood and washed red blood cell suspension through Nuclepore ftlter, MCI9042 improved filterabilities. Furthermore, MCI-9042 inhibited shear stress­ induced hemolysis in turbulent flow. These results in the three assessment systems on RBC deform ability indicate that MCI-9042 exhibits an improving effect on the deform ability of red blood cells and the efficacy of MCI-9042 is more potent than that of pentoxifylline. From the studies on the mode of action of MCI-9042 on RBC deform ability, we found that this compound reduced the membrane microvis­ cosity of red blood cells. It is therefore considered that MCI-9042 directly affects the membrane of red blood cells reducing their membrane microviscosity and con­ sequently improves RBC deform ability.

SummaryThe antithrombotic effect of MCI-9042, (±)-2-(dimethylamino)-1-[[o-(m-methoxyphenethyl)phenoxy] methyl] ethyl hydrogen succinate hydrochloride was investigated in three different experimental thrombosis models in animals. Simultaneous injection of serotonin and collagen into the tail vein in mice induced acute pulmonary thromboembolic death. MCI-9042 reduced the mortality in a dose dependent manner and its ED50 value was 1.9 mg/kg po. Ticlopidine (TCP) which is a positive reference compound as an antithrombotic drug reduced the mortality at doses of 10 mg/kg po and above. Cyproheptadine (CPH) and ketanserin (KTS) which are S2-serotonergic antagonists were also effective on the reduction of mortality. In mesenteric arterial thrombosis induced by electric stimulation in mice, MCI-9042 prolonged the occlusion time resulted from platelet thrombus formation (PD50: 23 mg/kg po). CPH and KTS prolonged the occlusion time as potent as MCI-9042, but TCP prolonged the occlusion time only at the high doses of 100 mg/kg po and above. In experimental arterial thrombosis which generated in implanted polyethylene tubing, MCI-9042 reduced the incidence of thrombus formation in the tubing and its ED50 value was 18 mg/kg po. TCP was also effective in this model with an ED50 of 170 mg/kg po. The present results lead to the consideration that serotonin plays a more important role in thrombus formation than that conjectured formerly, and suggest that MCI-9042 becomes a new kind of antithrombotic drug with S2-serotonergic receptor antagonism.

A series of [2-[(omega-aminoalkoxy)phenyl]ethyl]benzene derivatives were synthesized and evaluated for their ability to inhibit collagen-induced platelet aggregation in vitro and to protect experimental thrombosis in mice. The results showed that the compounds were in vitro inhibitors of collagen-induced platelet aggregation. Most of them were also effective in the mouse antithrombotic assay. The compounds were found to be potent antagonists to S2 serotonergic receptor, and good correlation (r = 0.85) between their S2 serotonergic receptor antagonism and their potency as platelet antiaggregatory drugs was observed. Among the compounds studied, mono[2-(dimethylamino)-1-[[2-[2-(3- methoxyphenyl)ethyl]phenoxy]methyl]ethyl] succinate hydrochloride (12b, MCI-9042) was selected for further pharmacological and toxicological evaluation.

CT-colonography (CT-C), a new diagnostic imaging technique for cancer of the large intestine--which is increasing rapidly owing to westernized eating habits--has advanced from the developmental stage to the stage of practical application, thanks to progress in MSCT and workstation development. Therefore, based on the results of CT-C application using 16 lines of MSCT to a screening test, we reviewed the usefulness of CT-C in our clinic. We supplemented defective depiction, and found that change of position was effective for virtual image exclusion. We consider that CT-C can support diagnosis if the target of screening tests is a polypoid lesion of more than 6 mm. In addition, it is expected that the number of examinations performed during office visits will increase because of the decreased invasiveness of the procedure, its lack of pain, and its ability to provide early lesion detection.

As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.

Anti-HIV-1 activity of tetrahydronaphthalene (THN) derivatives of lignan compounds was studied. THN derivatives prevented cell death caused by HIV-1 infection in MT-4 cells. They also inhibited giant cell formation by HIV-1 in Sup-T1 cells, and p24 production in HIV-1-infected H9 cells. The 50% effective concentration (ED50) of the most active compound, 1737 [5,6,7-trimethoxy-4-(3,4,5-trimethoxyphenyl)-1,3,3a,4,9,9a-hexahydron aphtho[2,3-c]thiophene], for inhibition of the cytopathic effects of HIV-1 infection ranged from 0.15 to 0.8 microM. The 50% cytotoxic concentration (CC50) of compound 1737 measured by the viability of MT-4 cells was 58 microM, indicating a selective index (CC50/ED50) of 70-400. Substitution of the phenyl ring with other structures markedly decreased cytotoxicity but did not affect the antiviral activity of the compounds. This resulted in compounds with a high selective index. One such compound was 1738 [7-methoxy5,6-methylenedioxy-4-(4-benzyloxy-3-methoxyphenyl)1,3,3a ,4,9,9a-hexahydronaphtho[2,3-c]thiophene], with a selective index higher than 770. The time-of-addition experiment indicated that these compounds acted at or near the reverse transcription step of the HIV-1 life cycle. THN derivatives inhibited HIV-1 reverse transcriptase (RT) in vitro at a concentration of 1 microM. Resistant viruses selected in the presence of THN derivatives showed some degree of cross-resistance to other nonnucleoside RT inhibitors, but not to the nucleoside RT inhibitor, AZT. THN derivatives failed to inhibit replication of pyridinone- and nevirapine-resistant HIV strains. However, compound 1737 inhibited replication of a TIBO-resistant strain more effectively than the wild-type HIV-1. Consistent with this result, compound 1737 also inhibited TIBO-resistant RT more effectively than the wild-type RT in vitro. These results suggested that THN derivatives interact with RT in a manner similar to but slightly different from that of other nonnucleoside HIV-1 RT inhibitors.

Several major histocompatibility complex class I (MHC-I) alleles are associated with lower viral loads and slower disease progression in human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections. Immune-correlates analyses in these MHC-I-related HIV/SIV controllers would lead to elucidation of the mechanism for viral control. Viral control associated with some protective MHC-I alleles is attributed to CD8+ T-cell responses targeting Gag epitopes. We have been trying to know the mechanism of SIV control in multiple groups of Burmese rhesus macaques sharing MHC-I genotypes at the haplotype level. Here, we found a protective MHC-I haplotype, 90-010-Id (D), which is not associated with dominant Gag-specific CD8+ T-cell responses. Viral loads in five D+ animals became significantly lower than those in our previous cohorts after 6 months. Most D+ animals showed predominant Nef-specific but not Gag-specific CD8+ T-cell responses after SIV challenge. Further analyses suggested two Nef-epitope-specific CD8+ T-cell responses exerting strong suppressive pressure on SIV replication. Another set of five D+ animals that received a prophylactic vaccine using a Gag-expressing Sendai virus vector showed significantly reduced viral loads compared to unvaccinated D+ animals at 3 months, suggesting rapid SIV control by Gag-specific CD8+ T-cell responses in addition to Nef-specific ones. These results present a pattern of SIV control with involvement of non-Gag antigen-specific CD8+ T-cell responses.

The nucleotide sequence of the gene for the envelope protein gp85 (SU) of the Schmidt-Ruppin subgroup A (NY) strain of Rous sarcoma virus [SRA(NY)] was determined, and the deduced amino acid sequence was compared with those of other avian sarcoma-leukosis viruses. Among the five host-range determinant sequences (vr1, vr2, hr1, hr2, and vr3), the host-range determinant sequence hr2 of SRA(NY) showed a significant deviation from the hr2 sequences of other subgroup A viruses, namely, RAV-1 and SRA(SF). A phylogenetic analysis of the amino acid sequence of this region indicated that this intra-subgroup diversity was as great as or even greater than the inter-subgroup diversity found among other subgroups of ASLV. Within the hr2 region, we found a short hypervariable segment that differs in length and sequence from hr2 of other subgroup-A viruses. The difference in the hr2 amino acid sequence between SRA(NY) and SRA(SF) is reflected in the predicted protein secondary structure of this region.

Hepatocyte growth factor (HGF) is a mitogen for hepatocytes, having high affinity for heparin. In this study, we examined the function of cell surface heparin-like molecules in HGF/receptor interaction and HGF-induced mitogenic activity using hepatocytes. Binding studies using 125I-HGF showed that more than 85% of bound HGF was released from the cell surface by washing with heparin. This procedure also released HGF from the c-Met protein, which is a component of the high-affinity receptor. In addition, heparitinase digestion of hepatocytes reduced the HGF bound to c-Met protein. Furthermore, excess heparin added during the binding of 125I-HGF to hepatocytes, significantly diminished HGF bound to c-Met protein. Moreover, when DNA synthesis of hepatocytes was repressed and retarded by excess HGF, exogenous heparin restored it. These results suggest that HGF is bound to c-Met protein and that its mitogenic activity is regulated by heparin-like molecules on hepatocytes.

The effect of hepatocyte growth factor/scatter factor (HGF/SF) on the proliferation of human skin fibroblasts was examined. At concentrations above 1.0 ng/ml, both native and recombinant human HGF/SF stimulated the DNA synthesis determined by [3H]thymidine incorporation, which was completely inhibited by an anti-human HGF/SF monoclonal antibody. The maximal DNA synthesis in the treated cells was nearly twice that in untreated cells. HGF/SF also caused an increase in the labelling index, DNA content and cell number. The effect of HGF/SF was more than additive to the maximal effect of insulin and epidermal growth factor, other mitogens for the fibroblasts. These results indicate that human skin fibroblasts are sensitive to the mitogenic action of HGF/SF.

Hepatocyte growth factor (HGF) is a heterodimeric protein consisting of a heavy chain and a light chain held by a disulfide bond. These chains are produced by endoproteolytic processing from a single chain precursor. In this study, we examined whether the processing is a prerequisite for the mitogenic activity of HGF on hepatocytes in primary culture. Single chain HGF was proteolytically converted to the heterodimeric form during incubation with hepatocytes and was as mitogenic as the heterodimeric form. When the conversion was inhibited by serine-protease inhibitors, the mitogenic activity of single chain HGF was markedly reduced. Furthermore, a mutant resistant to the proteolytic processing, which was prepared by in vitro mutagenesis, completely lost the mitogenic activity. From these results, we concluded that the single chain form of HGF is endoproteolytically processed by a serine-protease and that this processing is a prerequisite for the mitogenic activity of HGF.

We re-examined the generally accepted concept that replication of Rous sarcoma virus (RSV) requires host DNA synthesis. We used terminally differentiated chicken myotubes as the host because chromosomal DNA replication is completely abolished by the natural differentiation process. Southern blot analysis detected unintegrated viral DNA in both the nucleus and cytoplasm of infected myotubes. This indicated that reverse transcription of the infecting viral RNA and transport of the newly synthesized viral DNA into the nucleus proceeded normally in myotubes. However, restriction enzyme digestion of high M(r) DNA prepared from infected myotubes produced none of the fragments specific for RSV, indicating that the viral DNA had failed to integrate into the myotube chromosomal DNA. In these infected myotubes, viral RNA was detected by in situ hybridization. Northern blot analysis showed the presence of all three RSV mRNAs (38S, 28S and 21S). The amount of these viral RNAs in infected myotubes was comparable with that found in infected fibroblasts. We conclude that host DNA synthesis is required for RSV integration, but, in contrast to the generally accepted concept, viral DNA integration is not an absolute requirement for transcription of the RSV genome.

To evaluate the role of protein phosphorylation reactions in signal transduction of human hepatocyte growth factor (hHGF), now known to be the same protein as the scatter factor and tumor cytotoxic factor, we examined the effects of various inhibitors of protein kinases on the mitogenic activity of hHGF on rat hepatocytes in primary culture. Genistein, a specific inhibitor of tyrosine kinase, dose-dependently inhibited the effect of hHGF in stimulating DNA synthesis of hepatocytes. By contrast, 1-(5-isoquinolinesulfonyl)-2- methylpiperazine (H7), a specific inhibitor of protein kinase C, potentiated the stimulatory effect of hHGF on DNA synthesis of hepatocytes. H7 was effective at over 2 micrograms/ml and potentiated the effect of hHGF over 2-fold at 20 micrograms/ml. On the other hand, an inhibitor of Ca++/calmodulin-dependent protein kinase inhibited both the basal and hHGF-stimulated DNA synthesis in the cells, whereas an inhibitor of cyclic nucleotide-dependent protein kinases had little effect on the action of hHGF. These results suggest that tyrosine phosphorylation is required for stimulation of hepatocyte DNA synthesis by hHGF and that the action of hHGF is negatively regulated by protein kinase C activation.

SummaryMCI–9042, (±)–1–[2–[2–(3–methoxyphenyl)ethyl]phenoxy]–3–(dimethylamino)–2–propyl hydrogen succinate hydrochloride inhibited platelet aggregation induced by collagen and secondary aggregation by ADP or epinephrine at 10−6 M level in platelets of various species. The antiplatelet effect of MCI–9042 was potentiated in aggregation induced by a combination of serotonin with collagen. IC50 value of human platelet aggregation by the serotonin plus collagen was 1.0 × 10−7 M. MCI–9042 inhibited serotonin release accompanied with collagen-induced platelet aggregation, while it did not affect serotonin uptake into platelet. MCI–9042 also potently inhibited the S2-serotonergic receptor-mediated contraction of rat caudal artery by serotonin in a competitive manner with a Ki value of 1.79 × 10–8 M, while Si receptor- or adrenergic receptor-mediated vasoconstriction was inhibited more weakly. Platelet adhesiveness, c-AMP level in platelets and the conversion of arachidonic acid to thromboxane A2 were not influenced by MCI–9042. These results suggest that MCI–9042 is a selective S2-serotonergic receptor antagonist, exhibiting the inhibition of S2-serotonergic potentiated platelet aggregation and the suppression of blood vessel constriction mediated by S2-serotonergic receptor.

Four stereoisomers of 4-methyl-1-[N 2 -(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl)-L-arginyl]-2-piperidinecarboxylic acid were synthesized and examined for the inhibitory effect on thrombin. The inhibitory potency varied largely with the stereo-configuration of the 4-methyl-2-piperidinecarboxylic acid portion. The (2R, 4R)-isomer was the most potent inhibitor with a Ki of 0.019 μM, while the (2R, 4S) and (2S, 4R)-isomers showed the values of Ki 0.24 and 1.9 μM, respectively. The least potent inhibitor, (2S, 4S)-isomer, showed a Ki of 280 μM which is approximately 15,000 times that of (2R, 4R)-isomer.

The potency of thrombin inhibition by 4-methyl-1-[N2-[(3-methyl-1,2,3,4-tetrahydro-8-quinolinyl)-sulfony l]- L-arginyl]-2-piperidinecarboxylic acid (MQPA) depended on the stereoconformation of the 2-piperidinecarboxylic acid moiety. Ki values for bovine alpha-thrombin were 0.019 microM with (2R,4R)-MQPA, 0.24 microM with (2R,4S)-MQPA, 1.9 microM with (2S,4R)-MQPA, and 280 microM with (2S,4S)-MQPA. (2R,4R)-MQPA of the four stereoisomers of MQPA was also the most potent inhibitor for other trypsin-like serine proteases with Ki values of 5.0 microM for trypsin, 210 microM for factor Xa, 800 microM for plasmin, and 1500 microM for plasma kallikrein. Examination of the potency of thrombin inhibition by arginine derivatives related to MQPA in structure suggested the presence of a specific binding site for the carboxamide portion (C-terminal side). The relative inhibitory potency of the four stereoisomers of MQPA for trypsin was nearly identical with that for thrombin, suggesting that the specific binding site for the carboxamide portion is present in both enzymes. Modification of thrombin by phosphopyridoxylation or the presence of heparin did not significantly alter the binding of MQPA.

The general pharmacological action of TRQ was investigated, and the following results were obtained: With regard to its influence on the central nervous system, TRQ moderately potentiated the actions of hexobarbital (sleeping time) and methamphetamine (stereotyped behavior) at doses above 100 mg/kg, p.o. TRQ, however, had little influence on behavioral changes, EEG and motor function. TRQ only had slight influence on the respiratory and cardiovascular system at doses ranging from 0.1 to 3 mg/kg, i.v. Significant decrease in SBP and increases of HR, FAF and respiratory rate were observed after high doses (10-30 mg/kg, i.v.) of TRQ. TRQ also had little influence on contractility and pacemaker in isolated hearts, but moderately increased the coronary flow. The inhibitory effect of TRQ on the isolated smooth muscle was observed at high concentration and was non-specific. Furthermore, TRQ exhibited little influence on the autonomic nervous system. Among the effects of TRQ on the gastrointestinal system, it was shown that TRQ moderately increased the outflow of bile after doses above 1 mg/kg, i.v. TRQ also showed no remarkable actions on other aspects of the gastrointestinal system and blood coagulation system. Considering the present results, it may be suggested that there should be no serious problems in the application of TRQ as a hepatoprotective agent.

To evaluate the thrombin-inhibitors (OM-inhibitors) synthetized by the authors, their actions in vitro and in vivo have been investigated. Results obtained are summarized as follows: 1. (i) The inhibitory action of the OM-inhibitor (OM-205) is highly selective to thrombin when compared with trypsin, plasmin or reptilase. 2. (ii) The mode of inhibition of the OM-inhibitor (OM-46) to thrombin is competitive in the hydrolysis of Nα-benzoyl-DL-arginine p-nitroanilide. 3. (iii) The decreasing effects of thrombin infusion in rabbits on plasma fibrinogen content and platelets in number are remarkably blocked by the presence of the OM-inhibitor (OM-189) in the blood, which suggests that the OM-inhibitors, very effective in vitro, possess the anti-thrombin activity also in vivo.

MCI-2016 showed little influence on coagulation (APTT) and fibrinolysis (plasma clot lysis activated by urokinase) at doses (concentrations) as high as 300 mg/kg, p.o. or 8.6 X 10(-4) M. Hemolytic action of MCI-2016 was only observed at the concentrations above 2 mM. The drug also showed no influence on blood glucose level (30-300 mg/kg, p.o.). Effects of MCI-2016 on hemorheological properties were studied either in vitro or ex vivo. Above the doses (concentrations) of 100 mg/kg, p.o. and 10 microM, MCI-2016 suppressed the mechanical hemolysis and accelerated the membrane filtration rate. These effects of MCI-2016 were superior to those of cinepazide, Ca-hopantenate, meclofenoxate and pentoxyfylline. MCI-2016 also inhibited platelet aggregation induced by collagen with the IC 50 of 35 to 60 microM (rabbit and human platelets). Secondary aggregations of ADP and epinephrine were also inhibited by MCI-2016. As for reference drugs, bencyclane showed inhibitory patterns similar to MCI-2016. Other drugs examined exhibited little effect. In summary, it may be suggested that MCI-2016 exhibits beneficial influences in the clinical fields of cerebrovascular diseases.

We have studied the relationship between immortalization of SV40-transformed human embryonic fibroblasts and their SV40 integration sites. From several independently transformed cell pools, we have isolated clones which do not harbor unintegrated SV40 DNA. We have analysed whole-cell DNA from these clones, using the Southern blot method. Our results suggest that no specific integration sites in the cellular genome exist which are a prerequisite for the immortalization process. Although some integration sites were found to be predominant in pre-crisis clones, they could not be detected in the post-crisis clones. This suggests that none of these predominating sites is selected for during the crisis period.

Hepatocyte growth factor (HGF) promotes proliferation of cultured hepatocytes by its interaction with cell surface receptors. In this paper, we examined the metabolic fate of HGF using hepatocytes. Kinetic analysis using [125I]HGF showed that 40% of surface-bound HGF was rapidly internalized in hepatocytes within 30 min at 37 degrees C. Under these conditions, the amount of HGF-bound c-Met, the high-affinity receptor, decreased from the cell surface. Furthermore, the internalized HGF was degraded and released from the cells. These results indicate that cell surface-bound HGF is internalized and degraded by the receptors, including c-Met, on hepatocytes.

Our studies of synthetic thrombin inhibitors of arginine derivatives yielded very recently No. 805 (MCI-9038 or MD-805) having a specific stereostructure of 4-methyl-2- piperidinecarboxylic acid at its carboxamide portion which showed an extremely potent and selective inhibition of thrombin with a Ki of 0.019 μM.The effect of No. 805 on an experimental DIC was studied. An experimental DIC in rabbits was generated by a constant i.v. infusion of 0.1 M lactic acid and crude bovine placental tissue thromboplastin. A rapid decrease in platelet number and a gradual decrease in fibrinogen content in plasma were observed over the experiment period of 5 hrs. The i.v. infusion of No. 805 suppressed the decrease in platelet number and fibrinogen content dose- dependently from 1.0 to 31.6 μg/kg/min and the suppression of ca. 50% was attained at a dose of 3.16 μg/kg/min showing a plasma level as low as ca. 0.3 μM, while heparin given at a dose of 100 or 1,000 u/kg i.v. (x2) did not show a notable suppression of the platelet number decrease but a significant suppression of the fibrinogen content decrease. Thus, No. 805 was shown to be effective on the experimental DIC at lower plasma level, exhibiting more dominant effects on platelets than heparin. This result was carefully compared with those on other animal thrombosis.

Human fibroblasts (IMR90 and WI38) have a finite life span and provide a model system for studying cellular aging. In contrast to normal fibroblasts, SV40 transformed fibroblasts do not exhibit aging phenomena. We have examined the population doubling time, protein concentration, arginyl-tRNA transferase activity, and arginyl-tRNA transferase-directed modification of chromosomal proteins in nontransformed and SV40 virus transformed cells. From these studies it was found that the population doubling time and cellular protein content increase as the cells enter phase III, whereas the activity of arginyl-tRNA transferase and the ability of chromosomal proteins to accept arginine at the NH 2 -terminal end diminished progressively during cellular senescence. Furthermore, the above-mentioned parameters, which are associated with cellular aging in nontransformed cells, remained fixed at the time when the cells were exposed to SV40 viruses. In other words, the relative age of the culture determines the point at which fixation of age-associated parameters occurs. The transformed cells are then refractory to any subsequent aging phenomena.

The effect of a temperature shift from low (36 degrees C) to high (40 degrees C) temperature on human fibroblasts (IMR90) at various population doubling levels and IMR90 cells transformed by SV40 virus infection at a population doubling level of 30 (SV40/IMR90) was examined. Both IMR90 and SV40/IMR90 cells showed a decrease in cell saturation density at confluency, whereas an increase in population doubling time and protein content was noted when the cells were shifted up to 40 degrees C from 36 degrees C. The modification of IMR90 chromosomal proteins by arginyl-tRNA transferase was increased by the temperature shift, whereas NH2-terminal arginylation of SV40/IMR90 chromatin was not altered. Similarly, no appreciable change in 2-deoxyglucose uptake was noted with SV40/IMR90 cells at either temperature, although 2-deoxyglucose uptake by IMR90 cells was increased by the temperature shift. Additionally, the rate of 2-deoxyglucose uptake showed no difference between IMR90 and SV40/IMR90 cells. The above results support previous findings that environmental alterations, such as temperature shift can cause acceleration of cellular senescence. These findings also imply that cellular senescence remains fixed when viral transformation occurs and is rendered refractory to further age-associated alterations.