Two Novel Endopeptidases Released into the Medium during Mating of Gametes of Chlamydomonas reinhardtii

During the mating reaction between mt⁺ and mt^- gametes of Chlamydomonasreinhardtii, two novel endopeptidases, each of which was ableto digest the B chain of insulin, were released into the culturemedium, together with a gamete lytic enzyme (GLE) which is responsiblefor digestion of the gametic cell walls. Both endopeptidasesand GLE were copurified from the mating medium by column chromatographyon DEAE-cellulose and concanavalin A. Gel filtration separatedthe peptidases, which were unable to digest gametic cell walls,into two fractions, endopeptidase-1 and endopeptidase-2. Theseenzymes were also separated from GLE, which was unable to digestthe B chain of insulin. Endopeptidase-1, with a molecular massof about 200 kDa, cleaved the B chain of insulin at the Ala¹⁴-Leu¹⁵peptide bond, and this activity was inhibited by EDTA. Endopeptidase-2,with a molecular mass of about 110 kDa, digested the peptideat the Leu¹⁵-Tyr¹⁶ peptide bond and was sensitive to iodoacetateand chymostatin. When the cell walls of gametes of either mating-typewere digested prior to mating with exogenously added GLE, thetwo endopeptidases were released into the medium, a result thatsuggests that they are stored, like GLE, outside the plasmalemma. (Received March 25, 1994; Accepted June 13, 1994)     

Design, synthesis and structure-affinity relationships of aryloxyanilide derivatives as novel peripheral benzodiazepine receptor ligands

Since the peripheral benzodiazepine receptor (PBR) has been primarily found as a high-affinity binding site for diazepam in rat kidney, numerous studies of it have been performed. However, the physiological role and functions of PBR have not been fully elucidated. Currently, we presented the pharmacological profile of two high and selective PBR ligands, N-(2,5-dimethoxybenzyl)-N-(4-fluoro-2-phenoxyphenyl)acetamide (7-096, DAA1106) (PBR: IC(50)=0.28 nM) and N-(4-chloro-2-phenoxyphenyl)-N-(2-isopropoxybenzyl)acetamide (7-099, DAA1097) (PBR: IC(50)=0.92 nM). The compounds are aryloxyanilide derivatives, and identified with known PBR ligands such as benzodiazepine (1, Ro5-4864), isoquinoline (2, PK11195), imidazopyridine (3, Alpidem), and indole (5, FGIN-1-27) derivatives. The aryloxyanilide derivatives, which have been derived by opening the diazepine ring of 1, are a novel class as PBR ligands and have exhibited high and selective affinity for peripheral benzodiazepine receptors (PBRs). These novel derivatives would be useful for exploring the functions of PBR. In this paper, the design, synthesis and structure-affinity relationships of aryloxyanilide derivatives are described.     

Liposomal lactoferrin induced significant increase of the interferon-alpha (IFN-alpha) producibility in healthy volunteers

Interferon-alpha (IFN-alpha) producibility has been widely accepted as one of the important markers to evaluate the immune status. In this study, preliminary clinical tests were carried out to confirm the immunomodulatory activity of liposomal lactoferrin including IFN-alpha producibility and NK activity. In a primary open trial, the liposomal lactoferrin was administered to five healthy males for one week and various immunological indices were evaluated. Furthermore, ten healthy males were administered 319 mg per day of liposomal or non-liposomal lactoferrin for four weeks, and immune status was monitored at 0, 1 and 4 weeks after the intake as well as three weeks after stopping it. In this double-blinded comparative study, the IFN-alpha producibility was significantly increased only in the liposomal lactoferrin group during administration and decreased 3 weeks after stopping it, while the IFN-alpha producibility was unchanged in the non-liposomal lactoferrin group. Although the biological mechanism of IFN-alpha producibility enforced by liposomal lactoferrin has not been wholly understood, it is suggested to be a novel active constituent having preventive and therapeutic effects on inflammatory diseases, cancer and infectious diseases such as chronic hepatitis C.     

IL-12 gene therapy is an effective therapeutic strategy for hepatocellular carcinoma in immunosuppressed mice

Immunosuppressive therapy for organ transplantation is essential for controlling rejection. When liver transplantation is performed as a therapy for hepatocellular carcinoma (HCC), recurrent HCC is one of the most fatal complications. In this study, we show that intratumoral murine IL-12 (mIL-12) gene therapy has the potential to be an effective treatment for malignancies under immunosuppression. C3H mice (H-2(k)), injected with FK506 (3 mg/kg) i.p., were s.c. implanted with 2.5 x 10(6) MH134 cells (H-2(k)) and we treated the established HCC with electroporation-mediated gene therapy using mIL-12 plasmid DNA. Intratumoral gene transfer of mIL-12 elevated intratumoral mIL-12, IFN-gamma, and IFN-gamma-inducible protein-10, significantly reduced the number of microvessels and inhibited the growth of HCC, compared with HCC-transferred control pCAGGS plasmid. The inhibition of tumor growth in immunosuppressed mice was comparable with that of mIL-12 gene therapy in immunocompetent mice. Intratumoral mIL-12 gene therapy enhanced lymphocytic infiltration into the tumor and elicited the MH134-specific CTL response even under FK506. The dose of FK506 was sufficient to prevent the rejection of distant allogenic skin grafts (BALB/c mice, H-2(d)) and tumors, B7-p815 (H-2(d)) used as transplants, during mIL-12 gene therapy against MH134. Ab-mediated depletion studies suggested that the inhibition of tumor growth, neovascularization, and spontaneous lung metastasis by mIL-12 was dependent almost entirely on NK cells and partially on T cells. These results suggest that intratumoral mIL-12 gene therapy is a potent effective strategy not only to treat recurrences of HCC in liver transplantation, but also to treat solid malignant tumors in immunosuppressed patients with transplanted organ.     

Ku86 variant expression and function in multiple myeloma cells is associated with increased sensitivity to DNA damage

Ku is a heterodimer of Ku70 and Ku86 that binds to double-stranded DNA breaks (DSBs), activates the catalytic subunit (DNA-PKcs) when DNA is bound, and is essential in DSB repair and V(D)J recombination. Given that abnormalities in Ig gene rearrangement and DNA damage repair are hallmarks of multiple myeloma (MM) cells, we have characterized Ku expression and function in human MM cells. Tumor cells (CD38(+)CD45RA(-)) from 12 of 14 (86%) patients preferentially express a 69-kDa variant of Ku86 (Ku86v). Immunoblotting of whole cell extracts (WCE) from MM patients shows reactivity with Abs targeting Ku86 N terminus (S10B1) but no reactivity with Abs targeting Ku86 C terminus (111), suggesting that Ku86v has a truncated C terminus. EMSA confirmed a truncated C terminus in Ku86v and further demonstrated that Ku86v in MM cells had decreased Ku-DNA end binding activity. Ku86 forms complexes with DNA-PKcs and activates kinase activity, but Ku86v neither binds DNA-PKcs nor activates kinase activity. Furthermore, MM cells with Ku86v have increased sensitivity to irradiation, mitomycin C, and bleomycin compared with patient MM cells or normal bone marrow donor cells with Ku86. Therefore, this study suggests that Ku86v in MM cells may account for decreased DNA repair and increased sensitivity to radiation and chemotherapeutic agents, whereas Ku86 in MM cells confers resistance to DNA damaging agents. Coupled with a recent report that Ku86 activity correlates with resistance to radiation and chemotherapy, these results have implications for the potential role of Ku86 as a novel therapeutic target.     

Determination of Pseudomonas aeruginosa by Biochemical Test Methods

A new test method was devised for microbial gluconate oxidation, using an ammonium molybdate reagent. One loopful (about 2 mg wet wt.) of the test organism, grown on a nutrient agar plate for 18 hr, is transferred into 1 ml of the test liquid medium consisting of (NH₄)₂SO₄ 0.5 mg, potassium gluconate 10 mg, NaCl 5 mg, KH₂PO₄ 2 mg, MgSO₄·7H₂O 0.1 mg, and 1 ml of distilled water, incubated at 37 C for 6 hr without shaking, and then mixed with 3 ml of 1% aqueous solution of ammonium molybdate and 0.2 ml of glacial acetic acid. The mixture is heated in boiling water for 5 min, followed by abrupt cooling with running water. A deep blue colour appears in a positive result. A total of 39 strains of Pseudomonas aeruginosa showed positive results by this method, whereas Aeromonas, Vibrio, Proteus group, Klebsiella, Citrobacter and Enterobacter A group were all negative. Though some strains of Enterobacter B group showed a weak blue colour, it could be easily differentiated from the deep blue colour of Pseudomonas. Longer incubation of test microbes in the test medium, and longer heating of the reaction mixture gave unsatisfactory results.     

The power of proteasome inhibition in multiple myeloma

ABSTRACT

Introduction: Proteasome inhibitors (PIs) are therapeutic backbones of multiple myeloma treatment, with PI-based therapies being standards of care throughout the treatment algorithm. Proteasome inhibition affects multiple critical signaling pathways in myeloma cells and interacts synergistically with mechanisms of action of other conventional and novel agents, resulting in substantial anti-myeloma activity and at least additive effects.

Areas covered: This review summarizes the biologic effects of proteasome inhibition in myeloma and provides an overview of the importance of proteasome inhibition to the current treatment algorithm. It reviews key clinical data on three PIs, specifically bortezomib, carfilzomib, and ixazomib; assesses ongoing phase 3 trials with these agents; and looks ahead to the increasingly broad role of both approved PIs and PIs under investigation in the frontline and relapsed settings.

Expert commentary: Progress to date with PIs in multiple myeloma has been impressive, but there remain unmet needs and challenges, as well as increasing opportunities to optimize the use of these agents. Understanding discrepancies between PIs in terms of efficacy and safety profile is a key goal of ongoing research, along with proteomics-based efforts to identify potential biomarkers of sensitivity and resistance, thereby enabling increasingly personalized treatment approaches in the future.     

Short-term synaptic plasticity in the dentate gyrus of monkeys

The hippocampus plays an important role in learning and memory. Synaptic plasticity in the hippocampus, short-term and long-term, is postulated to be a neural substrate of memory trace. Paired-pulse stimulation is a standard technique for evaluating a form of short-term synaptic plasticity in rodents. However, evidence is lacking for paired-pulse responses in the primate hippocampus. In the present study, we recorded paired-pulse responses in the dentate gyrus of monkeys while stimulating to the medial part of the perforant path at several inter-pulse intervals (IPIs) using low and high stimulus intensities. When the stimulus intensity was low, the first pulse produced early strong depression (at IPIs of 10-30 ms) and late slight depression (at IPIs of 100-1000 ms) of field excitatory postsynaptic potentials (fEPSPs) generated by the second pulse, interposing no depression IPIs (50-70 ms). When the stimulus intensity was high, fEPSPs generated by the second pulse were depressed by the first pulse at all IPIs except for the longest one (2000 ms). Population spikes (PSs) generated by the second pulse were completely blocked or strongly depressed at shorter IPIs (10-100 or 200 ms, respectively), while no depression or slight facilitation occurred at longer IPIs (500-2000 ms). Administration of diazepam slightly increased fEPSPs, while it decreased PSs produced by the first pulse. It also enhanced the facilitation of PSs produced by the second stimulation at longer IPIs. The present results, in comparison with previous studies using rodents, indicate that paired-pulse responses of fEPSPs in the monkey are basically similar to those of rodents, although paired-pulse responses of PSs in the monkey are more delayed than those in rodents and have a different sensitivity to diazepam.